WO2020203480A1

WO2020203480A1 - Filter material for air filter

Info

Publication number: WO2020203480A1
Application number: PCT/JP2020/013091
Authority: WO
Inventors: 史洋佐藤; 松岡　昌伸; 健一保坂
Original assignee: 三菱製紙株式会社
Priority date: 2019-03-29
Filing date: 2020-03-24
Publication date: 2020-10-08
Also published as: CN113660991A; JP6824476B1; JPWO2020203480A1

Abstract

A filter material for an air filter, wherein two or more layers of nonwoven fabric are bonded by fusing, a plurality of design elements that are formed by the shapes of fused sections become a group to form a design showing a repeating pattern, the average area of one design element is 1-4.2mm², the minimum distance between neighboring design elements is 10mm or less, and the value of the fused section obstruction rate (percentage) divided by the average area of one design element is 0.8-1.2%/mm², said fused section obstruction rate corresponding to the ratio of the total area of the design elements included in the repeating pattern to the area of the repeating pattern formed by the design elements.

Description

Filter material for air filter

The present invention relates to a filter medium for an air filter used in an air conditioner or the like. Hereinafter, "filter material for air filter" may be abbreviated as "filter material".

In recent years, due to changes in the living environment and growing health consciousness, air conditioners such as air conditioners, air purifiers, humidifiers, and dehumidifiers are widely used in all living spaces such as houses, offices, factories, and automobiles. In these air conditioners, various air filters are often used to obtain purified air. These air conditioners and air filters are required to be highly functional and multifunctional year by year.

The air filter is required to have a dust collecting function and a deodorizing function. In addition to these, a function of removing a specific harmful gas, an antibacterial function, an antiviral function, an antiallergen function and the like are required. An air filter that realizes each function independently can be used, and if necessary, multiple types of air filters can be combined to make it multifunctional and installed in air conditioning equipment. However, since it is often difficult to take a large space for mounting the air filter, there is a demand for a multifunctional air filter by combining a plurality of functions into one air filter.

There are various types of air filters, but filter media for air filters made of non-woven fabric are widely used, and various non-woven fabrics are selected and used according to the application and performance. In order to improve the performance and performance, various non-woven fabrics are combined and further combined with different materials to form a filter medium. As a method of combination, a method of laminating a plurality of non-woven fabrics and materials and adhering them to each other is often used.

There is a method of using various adhesives as a method of laminating and laminating non-woven fabrics to form a laminated non-woven fabric, but adhesives may be disliked in applications where the odor or outgas generated from the adhesives is a problem. As another method, there is a method of bonding by fusion, which is preferable because no odor or outgas is generated because no adhesive is used. Examples of the fusion method include thermal fusion and ultrasonic fusion.

In the case of bonding by fusion, the fused part of the non-woven fabric is blocked and has no air permeability, and the performance as a filter medium is lost. Therefore, the smaller the area of the fused portion is, the smaller the pressure loss is, which is preferable as a filter medium. On the other hand, if the area of the fused portion is small, the adhesive strength of the fused portion is weakened. In addition, if the area of the non-fused portion is large, floating occurs between the layers of the laminated non-woven fabric, and when the filter medium is cut by post-processing, the non-woven fabric is turned over in the non-fused portion, causing a leak. This is a problem because it leads to defective air filters. Therefore, it is a problem to obtain an excellent filter medium which has low pressure loss, sufficient adhesive strength of the fused portion, and can suppress the occurrence of air filter defects due to floating and curling of the laminated non-woven fabric. It was.

In Patent Document 1, a heat-fused cellulose fiber containing hydroxymethylzantate is produced from viscose, a web is formed while the heat-fused cellulose fiber is extracted under a wet condition, and the embossing roller is used to form the web. A regenerated cellulose non-woven fabric sheet formed by heat-sealing the webs to each other while pressing the web to form an embossed web, and a pattern transferred to the embossed web when the embossing roller presses the web. It is composed of a combination of a linear first groove portion and a linear second groove portion, and the end portion of the second groove portion is arranged at a perpendicular position near an intermediate position in the length direction of the first groove portion, and further. By arranging the ends of the first groove in a right angle at a position perpendicular to the intermediate position in the length direction of the second groove, the first groove and the second groove are alternately and continuously connected to the embossed web. A recycled cellulose non-woven fabric sheet is disclosed, which is characterized by being arranged on the entire surface. Further, when the non-fused portion is regarded as the background and the embossed portion (fused portion) is regarded as the handle, in Patent Document 1, the fused portion such as a rectangle is adjacent to the fused portion on the grid points of the square lattice. A pattern is presented in which the orientation is changed by 90 °. However, when the pattern of Patent Document 1 is applied to a filter medium in which a non-woven fabric is laminated, if the lattice is small, the blockage rate is high and the pressure loss is high, and conversely, if the lattice is large, the laminated non-woven fabric stops floating. Was likely to occur, and improvement was needed.

Further, Patent Document 2 discloses an exterior nonwoven fabric used for an absorbent article such as a disposable diaper, and the exterior nonwoven fabric has a plurality of fused portions, and the plurality of fused portions are present. , A pattern that is repeatedly arranged with regularity so as to touch a virtual circle is disclosed. However, a non-fused portion corresponding to the diameter of the virtual circle is generated, and when the handle of the absorbent article is applied to the filter medium on which the non-woven fabric is laminated, the laminated non-woven fabric is liable to float or turn over, and improvement is required.

Utility Model Registration No. 3180626 International Publication No. 2018/123638 Pamphlet

An object of the present invention is to provide a filter medium for an air filter, which has a low pressure loss, a sufficient adhesive strength of a fused portion, and can suppress the occurrence of floating and curling of a laminated non-woven fabric.
Other issues and advantages of the present invention will become apparent from the following description.

The problem according to the present invention can be solved by the following means.

<1>
A filter medium for an air filter made of a laminated non-woven fabric in which two or more layers of non-woven fabric are bonded, and a plurality of pattern elements formed in the shape of the fused portion by fusing the above-mentioned bonding are formed as a set. The pattern is formed to show a repeating pattern, the area of one pattern element is 1 to 4.2 mm ² on average, the shortest distance between adjacent pattern elements is 10 mm or less, and the pattern element is formed. The value obtained by dividing the blockage rate (percentage) of the fused portion corresponding to the ratio of the total area of the pattern elements included in the repeating pattern to the area of the repeating pattern by the average value of the area of one pattern element is 0.8 to A filter medium for an air filter characterized by being 1.2% / mm ² .
<2>
The pattern of the repeating pattern formed by the pattern element is such that the invisible equilateral triangle ABC having a side of 20 to 24 mm coincides with the midpoint of each side of the equilateral triangle ABC and each vertex of the equilateral triangle ABC adjacent to each side. As described above, in the invisible repeating pattern arranged so as not to overlap each other in the same direction, the long side is 2 to 3 mm and the short side is on the straight line connecting the center of gravity G of the equilateral triangle ABC and the respective vertices A, B, and C. A rectangular handle element having a side of 0.5 to 1 mm is formed by being present so that the straight line and the long side of the rectangle are parallel to each other and the midpoint of the straight line and the center of gravity of the rectangle coincide with each other. The filter medium for an air filter according to <1>.
<3>
The air filter filter medium according to <2>, wherein the straight line connecting the centers of gravity G of two adjacent equilateral triangles ABC forms a minimum angle of 5 to 25 ° with respect to the flow direction of the filter medium processing.
<4>
The laminated non-woven fabric is a laminated non-woven fabric in which a charged non-woven fabric and a protective non-woven fabric are bonded together, and an adsorbent is sealed between the non-woven fabric for a support and the bonded non-woven fabric by a thermoplastic adhesive <1> to <3. > The filter medium for the air filter described in any one of.
<5>
The filter medium for an air filter according to any one of <1> to <3>, wherein the laminated non-woven fabric is a laminated non-woven fabric in which a non-woven fabric for a support and a charged non-woven fabric are bonded.
<6>
The filter medium for an air filter according to <5>, wherein the non-woven fabric for a support carries an adsorbent.
<7>
The air filter according to any one of <1> to <3>, wherein the laminated non-woven fabric is a laminated non-woven fabric in which a charged non-woven fabric, a protective non-woven fabric, and a non-woven fabric for a support are bonded, and the protective non-woven fabric is arranged on the side in contact with the outside air. Filter medium for.

According to the filter medium for an air filter of the present invention, the pressure loss is low, the adhesive strength of the fused portion is sufficient, and the occurrence of floating and curling of the laminated non-woven fabric can be suppressed.

A state in which the midpoint of each side of the invisible equilateral triangle ABC and the vertices of the equilateral triangle ABC adjacent to each side are aligned so as not to overlap each other (invisible repeating pattern). The figure shown. The figure which showed the arrangement of a pattern element.

The filter medium for an air filter of the present invention is a filter medium for an air filter made of a laminated non-woven fabric in which two or more layers of non-woven fabrics are bonded, and the above-mentioned bonding is performed by fusion, and a handle formed in the shape of a fused portion. A plurality of elements form a pattern showing a repeating pattern, and the area of one pattern element is 1 to 4.2 mm ² on average, and the shortest distance between adjacent pattern elements is 10 mm or less. The value obtained by dividing the blockage rate (percentage) of the fused portion corresponding to the ratio of the total area of the pattern elements to the total area of the laminated non-woven fabric by the average value of the area of one pattern element is 0.8 to 1. It is characterized by being 2% / mm ² .

The number of laminated non-woven fabrics constituting the filter medium may be at least two layers, and is not particularly limited. However, if the number of laminated layers is too large, the pressure loss may increase and the ventilation as the filter medium may not be ensured. It is preferably 6 layers or less.

Conventionally, various adhesives are sprayed and hot melt powder is sprayed as an adhesive as a bonding method in which two or more layers of non-woven fabrics are laminated and bonded, but these methods are bonded. The generation of odor and outgas from the agent can be a problem.

In the present invention, fusion is used as the bonding method. Examples of the fusion include thermal fusion and ultrasonic fusion. The bonding method by fusion is preferable because it does not use an adhesive and does not generate odor or outgas. On the other hand, the fused portion is completely closed and has no air permeability, and its performance as a filter medium is lost. Therefore, it is preferable that the area of the fused portion is as small as possible because the pressure loss is small. On the other hand, if the area of the fused portion is small, the adhesive strength of the fused portion is weakened. In addition, if the area of the non-fused portion is large, floating may occur between the layers of the laminated non-woven fabric, or turning may occur when the filter medium is cut by post-processing, resulting in leakage and other defects of the air filter. .. Therefore, it is necessary to devise the ratio of the area of the fused portion and the non-fused portion, and the shape, size, and arrangement of the fused portion.

Each fused portion is regarded as a "pattern element" constituting the "pattern", and the non-fused portion is regarded as a "background", which will be specifically described below. The "pattern" is formed by forming a set of a plurality of pattern elements to form a repeating pattern. In one of the repeating patterns consisting of a plurality of pattern elements and a background, the ratio of the total area of the plurality of pattern elements to the total area of the repeating pattern is the proportion of the area of the repeating pattern formed by the pattern elements. It corresponds to the ratio of the total area of the pattern elements included in the repeating pattern, and in the present invention, this ratio is referred to as "occlusion rate of the fused portion" or simply "occlusion rate". When one pattern element belongs to a plurality of adjacent patterns in common, it is considered that the pattern element belongs to a plurality of adjacent patterns at an equal ratio.
The blockage rate is preferably less than 4.0% from the viewpoint of reducing pressure loss. Further, from the viewpoint of ensuring the adhesive strength, the blockage rate is preferably 0.8% or more.

The pattern is composed of one or more "pattern elements", and the pattern elements are surrounded by a non-fused portion. The average value of the area of one pattern element constituting the pattern composed of a plurality of pattern elements is 1 to 4.2 mm ² . If the average value of the area of one handle element is less than 1 mm ² , the adhesive strength of the fused portion is insufficient, and it cannot be used because it is peeled off when used for post-processing of a filter medium or an air filter. On the other hand, in the case of more than 4.2 mm ² , the pressure loss becomes high due to the high occlusion rate. The maximum value of the shortest distance between adjacent handle elements is 10 mm or less. If it exceeds 10 mm, the laminated non-woven fabric in the non-fused portion may be lifted or turned up when the filter medium is cut in the post-processing, resulting in defects such as leaks in the air filter. Further, the minimum value of the shortest distance between adjacent handle elements is preferably 7.5 mm or more. If it is less than 7.5 mm, the pressure loss may increase.

Further, the value obtained by dividing the blockage rate by the average value of the area of one handle element is 0.8 to 1.2% / mm ² . This value indicates the density of pattern elements. If this value is less than 0.8% / mm ² , the pattern becomes rough, so the spacing between the pattern elements becomes large, and the laminated non-woven fabric in the non-fused part floats up or turns over when the filter medium is cut in post-processing. As a result, defects such as leaks occur in the air filter. On the other hand, when this value exceeds 1.2% / mm ² , the handle becomes dense and the pressure loss becomes high.

The shape of the pattern element is not particularly limited, and a plurality of types of shapes may exist. The aspect ratio is large, and an elongated shape is generally preferable from the viewpoint of adhesive strength. Taking a rectangle as an example, the short side is preferably 0.5 to 1 mm, and the long side is preferably 2 to 3 mm. However, if the short side is too small, sufficient adhesive strength may not be obtained.

There are no particular restrictions on the arrangement of pattern elements. If the handle is rough, the pressure loss will be low, but on the contrary, the distance between the handle elements will be large, and the air filter will be liable to be defective. If the handle is dense, the opposite is true. As a preferable specific example of the arrangement of the pattern elements that achieves both low pressure loss and as small a distance as possible, the orientation of invisible equilateral triangles ABC having a side of 20 to 24 mm should be oriented so as not to overlap each other. In an invisible repeating pattern that is aligned and arranged so that the midpoint of each side of the equilateral triangle ABC and the vertices of adjacent equilateral triangles coincide with each other, the center of gravity G of the equilateral triangle ABC and the vertices A and B , C has a rectangular handle element having a long side of 2 to 3 mm and a short side of 0.5 to 1 mm, and the line and the long side of the rectangle are parallel to each other and the midpoint of the line. An example of a filter medium in which a handle element is present so that the centers of gravity of the rectangles coincide with each other can be illustrated. This is an example, and is not limited to this. Note that FIG. 1 shows a state in which the midpoints of the sides of the invisible equilateral triangle ABC and the vertices of the equilateral triangles adjacent to each side are aligned so as not to overlap each other. It is a figure shown. This can be said to be an invisible repeating pattern.

Filter material processing such as non-woven fabric bonding processing by fusion and post-processing of filter material is often performed roll-to-roll with an emphasis on productivity. When the patterns form a repeating pattern, the pattern elements are arranged along the flow direction of the filter media processing. In the post-processing of the filter medium, the filter medium is often slit along the flow direction or cut in the direction orthogonal to the flow direction (width direction). At this time, when the slit wire or the cut wire passes only through the unfused portion of the filter medium, the strip-shaped non-woven fabric may be turned over, which may cause a defect of the air filter. In order to reduce the turning of the strip-shaped non-woven fabric, the handle can be made dense, the distance between the handle elements can be reduced, and the handle element can be increased. However, in either method, when the pressure loss increases. There is. When the minimum angle formed by the flow direction of the filter media processing and the line obtained by connecting the centers of gravity G of the adjacent invisible equilateral triangles ABC is 5 to 25 °, the entire pattern is maintained while maintaining the arrangement of the pattern elements. By tilting from the flow direction, it is possible to obtain an extremely excellent filter medium that can suppress the turning of the strip-shaped non-woven fabric and further suppress the occurrence of defects.

The optimum minimum angle for tilting the entire handle with respect to the flow direction of filter media processing differs depending on the handle. The invisible equilateral triangles ABC having a side of 20 to 24 mm, which are exemplified in the present invention, are arranged so as not to overlap each other, and the midpoints of the sides of the equilateral triangle ABC and the adjacent equilateral triangles are arranged. In an invisible repeating pattern arranged so that the vertices match, the long side is 2 to 3 mm and the short side is 0.5 to 1 mm on the line connecting the center of gravity G of the equilateral triangle ABC and each of the vertices A, B, and C. In a filter medium in which a rectangular pattern element exists, the line and the long side of the rectangle are parallel, and the pattern element exists so that the midpoint of the line and the center of gravity of the rectangle coincide with each other, the filter medium is processed. The minimum angle formed by the flow direction and the line obtained by connecting the centers of gravity G of adjacent invisible equilateral triangles ABC is preferably 5 to 25 °, more preferably 10 to 20 °.

Examples of the non-woven fibers include polyamide fibers, polyester fibers, polyalkylene paraoxybenzoate fibers, polyurethane fibers, polyvinyl alcohol fibers, polyvinylidene chloride fibers, polyvinyl chloride fibers, polyacrylonitrile fibers, and polyolefin fibers. Synthetic fibers such as fibers and phenolic fibers; Inorganic fibers such as glass fibers, metal fibers, alumina fibers, carbon fibers and activated carbon fibers; wood pulp, bamboo pulp, hemp pulp, kenaf pulp, straw pulp, bagas pulp, cotton linter pulp, Natural fibers such as cotton, wool and silk; recycled cellulose fibers such as recycled pulp of used paper and rayon; recycled fibers made from proteins such as collagen, polysaccharides such as alginic acid, chitin, chitosan and starch can be mentioned. In addition, fibers in which functions such as hydrophilicity and flame retardancy are imparted to these fibers can be mentioned. These fibers may be used alone or in combination of two or more. However, since the nonwoven fabric according to the present invention is bonded by fusion, it is preferable that at least one layer of the nonwoven fabric contains fibers made of a thermoplastic resin.

The method for manufacturing the non-woven fabric is not particularly limited, and the web is manufactured by a dry method, a wet papermaking method, a melt blow method, a spunbond method, a flash spinning method, an airlaid method, etc., depending on the purpose and application, and the strength of the web is exhibited. A non-woven fabric can be produced by appropriately combining the methods of making the fabric. As a method for expressing the strength of the web, a physical method such as a water flow confounding method, a needle punch method, a stitch bond method; a thermal bonding method such as a thermal bond method; an adhesive method such as a chemical bond method or a resin bond method is used. Method; etc.

The basis weight of the non-woven fabric is not particularly limited, but is preferably 5 to 300 g / m ² . If it exceeds 300 g / m ² , the pressure loss becomes high, and ventilation as a filter medium may not be ensured. Further, if it is less than 5 g / m ² , it may not be usable due to insufficient strength required for bonding.

If necessary, antibacterial, antifungal, antiviral, antiallergen, insect repellent, insecticidal, deodorant, fragrance, temperature sensitivity, heat retention, heat storage, heat storage, heat generation, heat absorption, waterproof, water resistant, water repellent, hydrophobic, hydrophilic , Dehumidification, humidity control, moisture absorption, oil repellency, parent oil, oil absorption, evaporation or sustained release of water, volatile chemicals, etc. may be added to the non-woven fabric.

Hereinafter, specific examples of a filter medium for an air filter containing a laminated non-woven fabric in which two or more layers of non-woven fabric are bonded by fusion will be given, but the present invention is not limited to these specific examples.

<Filter material A>
The filter medium A is a laminated non-woven fabric in which a charged non-woven fabric and a protective non-woven fabric are bonded together, and an air filter in which an adsorbent is sealed between the non-woven fabric for a support and the bonded non-woven fabric by a thermoplastic adhesive. It is a filter medium for use.

Examples of the fibers of the non-woven fabric for the support in the filter medium A include the fibers of the non-woven fabric described above. The average single fiber diameter of the fibers contained in the non-woven fabric for the support in the filter medium A is not particularly limited, but is preferably 6 to 25 μm, more preferably 8 to 20 μm, and more preferably 10 to 18 μm. More preferred. When the average single fiber diameter is less than 6 μm, the voids between the fibers may become narrow and the pressure loss may increase. On the other hand, when the average single fiber diameter exceeds 25 μm, the gaps between the fibers of the non-woven fabric for the support become large, and the adsorbent to be sealed may fall off.

The average single fiber diameter in the present invention is calculated by the following procedure. (1) Take a surface photograph of 500 to 1000 times with a microscope, and measure the width of 10 fibers from each sample, for a total of 100 fibers. (2) The average single fiber diameter is calculated from the average value of the measured 100 fibers.

The basis weight of the non-woven fabric for the support in the filter medium A is not particularly limited, but is preferably 10 to 300 g / m ² , more preferably 30 to 150 g / m ² , and 40 to 100 g / m ² . Is even more preferable. If the basis weight is less than 10 g / m ² , the strength and rigidity of the filter medium may be insufficient. On the other hand, if the basis weight exceeds 300 g / m ² , the pressure loss may become too high.

Examples of the method for producing the non-woven fabric for the support and the protective non-woven fabric in the filter medium A include the same method as the method for producing the non-woven fabric described above. The above-mentioned various functions may be added to the support non-woven fabric and the protective non-woven fabric in the filter medium A, if necessary.

As the charged non-woven fabric in the filter medium A, for example, an electret-processed spunbonded non-woven fabric, an electret-processed melt-blown non-woven fabric, or the like is used. An electret-processed melt-blown non-woven fabric is preferable because it can obtain high dust collecting performance. As the resin used for the fiber of the charged non-woven fabric, a resin having a high electric resistance is preferable, and a polyolefin resin such as polypropylene and polyethylene; an aromatic polyester resin such as polyethylene terephthalate; a synthetic polymer material such as a polycarbonate resin; Can be mentioned. Polypropylene, which has a low melting point and is easy to produce a melt-blown non-woven fabric, is more preferable. In addition, various additives may be added to the resin used for the charged non-woven fabric in order to enhance and improve the chargeability, weather resistance, thermal stability, mechanical properties, coloring, surface properties, or other properties. it can. In particular, since electret processing is performed, it is preferable to include an electret additive for the purpose of enhancing the chargeability. The electret additive preferably contains at least one electret additive selected from the group consisting of hindered amine compounds and triazine compounds.

The average single fiber diameter of the fibers contained in the charged non-woven fabric in the filter medium A is not particularly limited, but is preferably 0.1 to 8 μm, more preferably 0.5 to 6 μm, and 1 to 4 μm. Is even more preferable. When the average single fiber diameter is less than 0.1 μm, the voids between the fibers may become narrow and the pressure loss may increase. On the other hand, when the average single fiber diameter exceeds 8 μm, the gaps between the fibers of the charged non-woven fabric become large, and the dust collection performance may deteriorate.

The basis weight of the charged nonwoven fabric in the filter medium A is not particularly limited, but is preferably 5 to 60 g / m ² , more preferably 10 to 50 g / m ² , and preferably 15 to 40 g / m ^2. More preferred. If the basis weight is less than 5 g / m ² , the dust collection performance may deteriorate. On the other hand, if the basis weight exceeds 60 g / m ² , the pressure loss may become too high.

The thickness of the charged nonwoven fabric in the filter medium A is not particularly limited, but is preferably 0.05 to 1.0 mm, more preferably 0.1 to 0.6 mm, and further preferably 0.15 to 0.5 mm. Is. If the thickness of the charged non-woven fabric is less than 0.05 mm, the dust collection performance may be inferior. On the other hand, if it exceeds 1.0 mm, it becomes difficult to perform pleating, and the height of the pleats may be uneven.

Examples of the fibers of the protective non-woven fabric in the filter medium A include the fibers of the non-woven fabric described above. The average single fiber diameter of the fibers contained in the protective nonwoven fabric in the filter medium A is not particularly limited, but is preferably 6 to 20 μm, more preferably 8 to 16 μm, and even more preferably 10 to 15 μm. .. When the average single fiber diameter is less than 6 μm, the voids between the fibers may become narrow and the pressure loss may increase. On the other hand, when the average single fiber diameter exceeds 20 μm, the bonding points between the fibers of the protective nonwoven fabric are reduced, the strength of the protective nonwoven fabric itself is lowered, and the bonding process may not be possible.

The basis weight of the protective nonwoven fabric in the filter medium A is not particularly limited, but is preferably 5 to 60 g / m ² , more preferably 8 to 40 g / m ² , and preferably 10 to 30 g / m ^2. More preferred. If the basis weight is less than 5 g / m ² , it may not be possible to bond the protective non-woven fabric neatly due to insufficient strength of the protective non-woven fabric itself. On the other hand, if the basis weight exceeds 60 g / m ² , the pressure loss may become too high.

The adsorbent in the filter medium A is mainly used for the purpose of removing a bad odor. Specifically, adsorbents such as activated charcoal, impregnated activated charcoal, natural and synthetic zeolite, sepiolite, active alumina, activated white clay, ion exchange resin, iron ascorbic acid, iron phthalocyanine derivative; low temperature such as manganese oxide and perovskite type catalyst Oxidation catalyst; Photocatalyst such as titanium oxide and zinc oxide; Plant extract components such as catechin, tannin and flavonoid; Iron compounds such as iron oxide; Zinc oxide, magnesium oxide, silica, silica-zinc oxide complex, silica-alumina oxidation Examples thereof include zinc oxide, manganese dioxide, composite phyllosilicate, cyclodextrin, a mixture of ascorbic acid and divalent iron salt, a mixture of vitamin B group and phosphate, and the like. The shape of these adsorbents is not particularly limited, but it is preferably in the form of particles, and the specific surface area is preferably 50 to 2000 m ² / g. For example, in the case of activated carbon, it is determined by calculating the dust removal performance and the number of durable days specified in JEM 1467-1995. A plurality of these adsorbents may be used in combination as needed, or a hybrid adsorbent in which these adsorbents are combined may be used.

The amount of the adsorbent sealed in the filter medium A is not particularly limited, but is preferably 30 to 500 g / m ² , more preferably 50 to 400 g / m ² , and 100 to 300 g / m ^2. Is more preferable. If the encapsulation amount is less than 30 g / m ² , sufficient deodorizing performance may not be obtained. On the other hand, if it exceeds 500 g / m ² , the pressure loss may become too high.

The thermoplastic adhesive in the filter medium A is mainly composed of a thermoplastic resin, and the thermoplastic resin includes an ethylene vinyl acetate copolymer or a modified product thereof, an ethylene acrylate copolymer, an ionomer, a polyamide, a polyester, a polyethylene, and the like. Examples thereof include resins such as polypropylene and polyurethane.

The softening point or melting point of the thermoplastic adhesive is not particularly limited, but may be appropriately selected in consideration of the post-processing conditions of the filter medium, the operating environment temperature, the non-woven fabric for the support, the non-woven fabric for bonding, the heat resistance of the adsorbent, and the like. good.

The shape of the adsorbent or the thermoplastic adhesive in the filter medium A is preferably powdery, granular, whisker-like or short fibrous, and the distribution of the adsorbent in the filter medium can be made uniform.

When the adsorbent or the thermoplastic adhesive in the filter medium A is powdery or granular, the particle size is preferably 10 to 100 mesh, more preferably 15 to 90 mesh, and 20 to 80 mesh. It is more preferable to have. If the particle size is less than 10 mesh, problems such as cracking of the adsorbent during pressurization and non-uniform adhesion between the support non-woven fabric and the bonded non-woven fabric may occur, while the particle size of 100 mesh is used. If it exceeds the limit, problems such as detachment from the eyes of the filter medium may occur.

The mass ratio (S / T) of the adsorbent (S) and the thermoplastic adhesive (T) in the filter medium A is preferably 0.3 to 4, more preferably 0.4 to 2.8. It is more preferably 0.6 to 2.5. If the mass ratio (S / T) is smaller than 0.3, the thermoplastic adhesive covers the surface of the adsorbent, so that the deodorizing performance is significantly lowered and the air permeability of the filter medium may be impaired. On the other hand, if the mass ratio (S / T) is larger than 4, the adhesive strength may be insufficient, and the non-woven fabric for the support and the laminated non-woven fabric may be easily peeled off or the adsorbent may be peeled off.

In the filter medium A, the filter medium is made by spraying an adsorbent and a thermoplastic adhesive on a non-woven fabric for a support, superimposing a laminated non-woven fabric on the non-woven fabric, and heating to develop the adhesiveness of the thermoplastic adhesive. It is made into a non-woven fabric. It is preferable that the charged non-woven fabric side of the laminated non-woven fabric is in contact with the adsorbent. When the adsorbent and the thermoplastic adhesive are sprayed on the non-woven fabric for the support, both may be sprayed individually, but if there is no particular effect on the deodorizing property, a premixed mixture may be sprayed. preferable. Examples of the spraying method include spraying by free fall from the lower part of the hopper, spraying by blowing air dispersed in the air, spray coating and die coating in which the water system is dispersed.

In the filter medium A, the heating in the adsorbent encapsulation step is not particularly limited, but is basically classified into two methods. That is, one is a method in which a thermoplastic adhesive, preferably an adsorbent and a thermoplastic adhesive, is sprayed on a non-woven fabric for a support and then heated. The other is a method in which an adsorbent and a thermoplastic adhesive are sprayed on the non-woven fabric for the support, the laminated non-woven fabric is laminated, and then heated. In the present invention, either heating method may be used as desired, or both heating methods may be used in combination.

In the filter medium A, the integration of the non-woven fabric for the support and the laminated non-woven fabric after being overlapped can be achieved by pressurizing, and for example, a method of passing between the pressurized rolls can be adopted. The degree of pressurization may be appropriately set in consideration of the adhesive strength, the crushing of the adsorbent, the influence on the air permeability, and the like.

<Filter material B>
The filter medium B is a filter medium for an air filter in which the laminated non-woven fabric is a laminated non-woven fabric in which a non-woven fabric for a support and a charged non-woven fabric are bonded together.

In the filter medium B, the basis weight of the non-woven fabric for the support is preferably 20 to 120 g / m ² , more preferably 30 to 100 g / m ² , and even more preferably 40 to 80 g / m ² . If the basis weight is less than 20 g / m ² , the strength and rigidity of the filter medium will be insufficient, and the filter medium may be deformed when pleated. On the other hand, if the basis weight exceeds 120 g / m ² , the pressure loss may become too high.

The bonding method between the fibers of the non-woven fabric for the support in the filter medium B is preferably a chemical bond method or a thermal bond method. In the needle punching method and the spunlacing method, fibers are three-dimensionally entangled using a needle or a water stream to develop strength, which is relatively flexible and inferior in rigidity. Therefore, when pleated, the amount of ventilation is increased. If it increases, the filter medium may be deformed.

Examples of the fibers of the non-woven fabric for the support in the filter medium B include the same fibers as the fibers of the non-woven fabric described above. The average single fiber diameter of the fibers contained in the non-woven fabric for the support is not particularly limited, but is preferably 6 to 25 μm, more preferably 8 to 20 μm, and further preferably 10 to 18 μm. When the average single fiber diameter is less than 6 μm, the voids between the fibers may become narrow and the pressure loss may increase. On the other hand, when the average single fiber diameter exceeds 25 μm, the gaps between the fibers of the non-woven fabric for the support become large, and the rigidity may be inferior.

The above-mentioned various functions may be added to the non-woven fabric for the support in the filter medium B, if necessary.

Examples of the charged nonwoven fabric in the filter medium B include the charged nonwoven fabric in the filter medium A described above.

<Filter material C>
The filter medium C is a laminated non-woven fabric in which a laminated non-woven fabric is bonded to a non-woven fabric for a support and a charged non-woven fabric, and is a filter medium for an air filter in which the non-woven fabric for a support carries an adsorbent.

Examples of the fibers of the non-woven fabric for the support in the filter medium C include the fibers of the non-woven fabric described above. The average single fiber diameter of the fibers contained in the non-woven fabric for the support in the filter medium C is not particularly limited, but is preferably 6 to 25 μm, more preferably 8 to 20 μm, and more preferably 10 to 18 μm. More preferred. When the average single fiber diameter is less than 6 μm, the voids between the fibers may become narrow and the pressure loss may increase. On the other hand, when the average single fiber diameter exceeds 25 μm, the gaps between the fibers of the non-woven fabric for the support become large, and the rigidity may be inferior.

Examples of the method for producing the non-woven fabric for the support in the filter medium C include the same method as the above-mentioned method for producing the non-woven fabric.

The basis weight of the non-woven fabric for the support in the filter medium C is preferably 25 to 130 g / m ² , more preferably 30 to 100 g / m ² , and even more preferably 40 to 80 g / m ² . If the basis weight is less than 25 g / m ² , the strength and rigidity of the filter medium may be insufficient. If the basis weight exceeds 130 g / m ² , the pressure loss may become too high.

The thickness of the non-woven fabric for the support in the filter medium C is preferably 0.2 to 1.4 mm, more preferably 0.3 to 1.2 mm, and further preferably 0.4 to 1.0 mm. .. If the thickness of the non-woven fabric for the support is less than 0.2 mm, it becomes difficult to perform pleating, and the air filter may be deformed when the pleated air filter is used at a high wind speed. On the other hand, if it exceeds 1.4 mm, it becomes difficult to perform pleating, and the height of the pleats may be uneven.

As the adsorbent in the filter medium C, aldehydes such as formaldehyde and acetaldehyde; amines such as ammonia and trimethylamine; lower fatty acids such as acetic acid and isovaleric acid; mercaptans such as methyl mercaptan; SO ₂ , NO ₂ ; toluene, Examples thereof include adsorbents that adsorb malodorous gas components such as aromatic hydrocarbons such as xylene. For example, iron-based compounds such as activated charcoal, natural zeolite, synthetic zeolite, activated alumina, activated clay, sepiolite, iron oxide, zinc oxide, magnesium oxide, aluminum silicate, silica, silica-zinc oxide complex, silica-alumina-oxidation. Examples include zinc composites and composite phyllosilicates. In addition, a mixture thereof and the like can be mentioned. It is more preferable that the particles of these adsorbents are modified with a compound capable of chemically adsorbing the target gas.

For example, in an aldehyde adsorbent in which the target gas is an aldehyde, examples of the compound capable of chemically adsorbing the aldehyde that modifies the particles of the adsorbent include an amino compound, a saturated cyclic secondary amine compound (for example, morpholin), an azole compound, and an aroma. Group amino acid acidic salts (for example, o-, m-, p-aminobenzoic acid, o-, m-, p-aminosalicylic acid, etc.), imidazole and / or derivatives thereof, acid hydrazide compounds, polyamine compounds, aminoguanidine salt compounds, etc. Can be mentioned.

The adsorbent preferably has an integrated volume percentage D ₅₀ of 1 to 100 μm, more preferably 3 to 60 μm, and even more preferably 5 to 50 μm. When the cumulative volume percentage D ₅₀ of the adsorbent is less than 1 μm or more than 100 μm, the adsorbent may fall off more often and the deodorizing performance may deteriorate. The adsorbent having a suitable integrated volume percentage D ₅₀ can be obtained, for example, by classifying the pulverized adsorbent with a sieve. In the present invention, the integrated volume percentage D ₅₀ is an integrated value in the particle size distribution of the adsorbent measured using a laser diffraction / scattering particle size distribution measuring device (trade name MT30002 manufactured by Microtrac Bell Co., Ltd.). Is a particle size of 50%.

Regarding the content of the adsorbent in the present invention, in order to obtain a filter medium that is easier to pleate, the content is preferably 4 to 40 g / m ² , more preferably 5 to 25 g / m ² , and 10 to 15 g / m ^2. It is more preferably m ² .

The method for supporting the adsorbent on the non-woven fabric for the support is not particularly limited as long as the adsorbent can be supported on the non-woven fabric for the support as uniformly as possible. An example is a method in which a dispersion liquid is applied as a coating liquid to a non-woven fabric for a support by coating, spray coating, or the like, and the solvent or dispersion medium is removed by a method such as drying to support the dispersion.

When the non-woven fabric for the support carries the adsorbent, an amount of binder that does not interfere with the effect of the adsorbent can be used. Examples of the water-soluble binder include polyvinyl alcohol and starch. Examples of the water-dispersible binder include poly (meth) acrylic acid esters, polyvinyl acetate, polyvinyl chloride, styrene-acrylic resin, vinyl chloride-acrylic resin, silicone resin, styrene-butadiene resin and the like. Be done. The water-dispersible binder may be in the form of an emulsion. Binders are not limited to these.

The binder content is not particularly limited, but in order to prevent the adsorbent from falling off, it is preferable that the binder content is 10% by mass or more based on the solid content mass with respect to the adsorbent. Further, in order to obtain higher adsorption performance, it is preferably 50% by mass or less.

Examples of the charged non-woven fabric in the filter medium C include the charged non-woven fabric in the filter medium A described above.

<Filter material D>
The filter medium D is a laminated non-woven fabric in which a charged non-woven fabric, a protective non-woven fabric, and a non-woven fabric for a support are bonded to each other, and the protective non-woven fabric is arranged on the side in contact with the outside air.

The specific structure of the filter medium D is a three-layer structure of a protective non-woven fabric / a charged non-woven fabric / a non-woven fabric for a support, or a four-layer structure of a protective non-woven fabric / a charged non-woven fabric / a protective non-woven fabric / a non-woven fabric for a support. The "side in contact with the outside air" means the surface side (upstream side) where air flows in or the surface side (downstream side) where air flows out in the filter medium for an air filter. The filter medium D is a filter medium that can be repeatedly used by washing with water, that is, has excellent resistance to repeated washing with water.

Examples of the charged non-woven fabric in the filter medium D include the charged non-woven fabric in the filter material A described above.

The protective non-woven fabric in the filter medium D is preferably composed of polyolefin fibers. Polyolefin-based resins that are raw materials for polyolefin-based fibers include propylene homopolymers, propylene and various α-olefin copolymers; polyethylene-based resins include ethylene homopolymers, and ethylene and various α-olefin copolymers. For example, coalescence. Polypropylene resin is particularly preferably used because of its spinnability and strength characteristics. Further, the protective non-woven fabric can be supported with a water-repellent agent such as a water-repellent silicone resin or a fluororesin in order to further enhance and improve the resistance to repeated washing with water. The protective nonwoven fabric in the filter medium D may be provided with the above-mentioned various functions, if necessary.

The average single fiber diameter of the fibers contained in the protective non-woven fabric in the filter medium D is preferably 5 to 30 μm, more preferably 8 to 20 μm, and further preferably 10 to 17 μm. If the average single fiber diameter exceeds 30 μm, the voids between the fibers of the protective non-woven fabric become large, and the resistance to repeated washing with water may be inferior. On the other hand, if the average single fiber diameter is less than 5 μm, the voids between the fibers may become narrow and the pressure loss may increase.

The basis weight of the protective nonwoven fabric in the filter medium D is preferably 5 to 50 g / m ² , more preferably 8 to 40 g / m ² , and even more preferably 10 to 20 g / m ² . If the basis weight exceeds 50 g / m ² , the pressure loss may increase, while if the basis weight is less than 5 g / m ² , the resistance to repeated washing with water may be inferior.

The thickness of the protective nonwoven fabric in the filter medium D is not particularly limited, but is preferably 0.05 to 1.0 mm, more preferably 0.1 to 0.6 mm, still more preferably 0.15 to 0.5 mm. Is. If the thickness of the protective non-woven fabric is less than 0.05 mm, the resistance to repeated washing with water may be inferior. On the other hand, if it exceeds 1.0 mm, it becomes difficult to perform pleating, and the height of the pleats may be uneven.

Examples of the non-woven fabric for the support in the filter medium D include the non-woven fabric for the support in the filter medium C described above.

The filter medium for an air filter of the present invention may be used as a single plate, but may also be used in a shape that has been subjected to wavy processing such as a mountain valley-shaped folding process or a corrugated cardboard process, which is generally called pleating. Further, it may be used as a roll filter processed into a winding shape.

The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to the Examples. In addition, Examples 6 to 10, 15 to 20, 29 to 30, 38 to 40, 44 to 50 and Comparative Examples 5 to 10, 15 to 20, 25 to 30, 35 to 40, 45 to 50 are missing numbers.

≪Evaluation method≫
[Evaluation method of pressure loss 1]
The obtained filter medium was cut so as to have a ventilation size of 300 × 300 mm. This cut filter medium was installed in a test wind tunnel where air could be introduced at a constant wind speed so that there would be no leakage from the periphery of the filter medium and no slack would occur. The pressure loss was measured by measuring the differential pressure between the upstream side and the downstream side of the filter medium with a manometer under the condition of a wind speed of 0.10 m / s.

⊚ (Excellent): The pressure loss is less than 60 Pa.
◯ (Good): The pressure loss is 60 Pa or more and less than 70 Pa.
X (Poor): The pressure loss is 70 Pa or more.

[Evaluation method of pressure loss 2]
The obtained filter medium was cut so as to have a ventilation size of 300 × 300 mm. This cut filter medium was installed in a test wind tunnel where air could be introduced at a constant wind speed so that there would be no leakage from the periphery of the filter medium and no slack would occur. The pressure loss was measured by measuring the differential pressure between the upstream side and the downstream side of the filter medium with a manometer under the condition of a wind speed of 0.5 m / s. From the measured values, it was judged as follows.

◯ (Excellent): The pressure loss is less than 50 Pa.
Δ (Good): The pressure loss is 50 Pa or more and less than 70 Pa.
X (Poor): The pressure loss is 70 Pa or more.

[Evaluation method of adhesive strength]
The obtained filter medium was pleated as a post-processing using a reciprocating pleating machine. The filter medium after pleating was confirmed, and the presence or absence of peeling of the fused portion was confirmed, and the determination was made as follows.

◯ (Good): There is no peeling and there is sufficient adhesive strength.
× (Poor): There is peeling, and the adhesive strength is insufficient.

[Post-workability evaluation method]
In the above-mentioned pleating process, pleating was performed while slitting the width to 186 mm, the pleated ridge height was set to 28 mm, and 41 folds were used as one air filter to cut the filter medium. While holding the pleated filter medium so that the folds are even and fit in a rectangular body of 186 x 200 x 28 mm, apply a hot melt adhesive of ethylene vinyl acetate resin so as to close all the slit end faces of the filter medium. A strip-shaped, 1 mm-thick, 200 g / m ² polyester spunbonded non-woven fabric having a width of 30 mm and a length of 250 mm, which was applied to a thickness of about 2 mm, was attached to fix the pleated filter medium. The excess spunbonded non-woven fabric was cut so that the outer shape of the air filter was a rectangular parallelepiped of 200 × 200 × 30 mm to obtain an air filter. 100 air filters were prepared. Check the manufactured air filter, and if the filtered material that has been pasted is lifted or turned over, or if the height of the folds of the air filter is uneven, it is considered as "defective", and the defective rate of the air filter is calculated and described below. The post-workability was determined as described above.

◯ (Excellent): The defective rate is 1% or less.
Δ (Good): The defective rate is more than 1% and 5% or less.
× (Poor): The defective rate is more than 5%.

[Evaluation method of dust collection efficiency]
The obtained filter medium was cut so as to have a ventilation size of 300 × 300 mm. This cut filter medium was installed in a test wind tunnel where air could be introduced at a constant wind speed so that there would be no leakage from the periphery of the filter medium and no slack would occur. The number of atmospheric dust particles with a particle size of 0.3 to 0.5 μm on the upstream and downstream sides of the filter medium is measured with a particle counter under the condition of a wind speed of 0.5 m / s, and collected from the measurement results on the upstream and downstream sides. The dust efficiency (%) was calculated. From the calculated value, it was judged as follows.

◯ (Excellent): The dust collection efficiency is 99.97% or more.
Δ (Good): The dust collection efficiency is 99.00% or more and less than 99.97%.
X (Poor): The dust collection efficiency is less than 99.00%.

[Evaluation method of deodorizing performance (aldehyde)]
The obtained filter medium was cut to a size of 100 mm × 100 mm and allowed to stand in a 100 liter closed container. Then, 30 minutes after injecting 10 ppm of acetaldehyde into the container, the acetaldehyde concentration (ppm) in the container was measured by gas chromatography. The gas removal rate (%) was calculated from the initial concentration of acetaldehyde and the measured value. From the calculated value, it was judged as follows.

⊚ (Excellent): The gas removal rate is 80 to 100%.
◯ (Good): The gas removal rate is 50% or more and less than 80%.
Δ (Average): The gas removal rate is 20% or more and less than 50%.
X (Poor): The gas removal rate is less than 20%.

[Evaluation method of deodorizing performance (sulfur dioxide)]
The obtained filter medium was cut so as to have a ventilation size of 300 × 300 mm, and a sample was prepared separately. An air purifier (Daikin ACEF3DS) equipped with the sample was installed in a 1 m ³ stainless steel box, and all genuine filters other than the sample were removed. Odor gas (sulfur dioxide) was injected so that the initial concentration in the box was about 8.0 ppm, and then the air purifier was operated in turbo mode to measure the concentration (ppm) in the box after 60 minutes. .. The gas removal rate (%) was calculated from the initial concentration of odorous gas and the measured value. From the calculated value, it was judged as follows.

◯ (Excellent): The gas removal rate is 70% or more.
Δ (Good): The gas removal rate is 30% or more and less than 70%.
X (Poor): The gas removal rate is less than 30%.

[Evaluation method of repeated washing resistance]
The four sides of the filter medium cut to a size of 300 × 300 mm were heat-welded and sealed using a heat sealer machine. Then, after soaking in water for 20 minutes, it is exposed to running water for 1 minute, and then dried at 90 ° C. for 1 hour, which is regarded as one cycle. For each cycle, the dust collection efficiency was measured by the method described above, the test was repeated until the dust collection efficiency became less than 90%, and the result was judged based on the following evaluation criteria.

◯ (Excellent): The number of cycles is 60 or more.
Δ (Good): The number of cycles is 40 or more and less than 60.
X (Poor): The number of cycles is less than 40 times.

Example 1
And basis weight of 70 g / ^{m 2} polyester spun bond nonwoven fabric, a polypropylene meltblown having a basis weight of 25 g / ^{m 2} was permanently charged working, it is 0.3 ~ 0.5 [mu] m counting collection efficiency at 5.3 cm / sec under , 99.97% or more of the non-woven fabric was used to prepare a filter medium made of a laminated non-woven fabric bonded by ultrasonic heat fusion. At this time, a filter medium was obtained in which the handle, which is the fused portion, formed a repeating pattern, and the handle elements constituting the handle were arranged as follows.

[Explanation of Arrangement of Pattern Elements of Example 1]
In the ultrasonic heat fusion process, the invisible equilateral triangles ABC are aligned so that they do not overlap each other, and the midpoints of each side of the equilateral triangle ABC are arranged so that the vertices of adjacent equilateral triangles coincide with each other. (Fig. 1). There are different rectangular pattern elements on the three lines connecting the center of gravity G of the equilateral triangle ABC and the vertices A, B, and C, and each line and the length of each rectangle existing on the line. The sides are parallel, and each pattern element is such that the midpoint of the line in which it resides coincides with the center of gravity of the rectangle (FIG. 2). The length of one side of the invisible equilateral triangle ABC is 22 mm, the long side of the rectangle is 2 mm, and the short side is 0.5 mm.

Example 2, Comparative Example 1
Example 2 is the same as Example 1 except that the length of one side of the invisible equilateral triangle ABC is 20 mm, and Example 1 except that the length of one side of the invisible equilateral triangle ABC is 25 mm. The same filter medium of Comparative Example 1 as above was obtained.

Example 3, Comparative Example 2
It is the same as Example 2 except that the size of the handle element is 1 mm × 3 mm, and it is the same as Example 2 except that the size of the handle element is 0.5 mm × 1 mm. A filter medium of Comparative Example 2 was obtained.

Example 4
The filter medium of Example 4 was obtained in the same manner as in Example 1 except that the size of the handle element was 1.2 mm × 3.5 mm and the length of one side of the invisible equilateral triangle ABC was 24 mm.

Comparative Example 3
A filter medium of Comparative Example 3 was obtained, which was the same as that of Example 3 except that the length of one side of the invisible equilateral triangle ABC was 19 mm.

Comparative Example 4
A filter medium of Comparative Example 4 which was the same as that of Example 4 except that the size of the handle element was 1.2 mm × 4 mm was obtained.

Example 5
Example 1 except that the minimum angle formed by the flow direction of the filter medium and the line obtained by connecting the centers of gravity G of the adjacent invisible equilateral triangles ABC when the filter medium is bonded is set to 19 °. The same filter medium as in Example 5 was obtained.

Table 1 shows the evaluation results of the filter media of Examples 1 to 5 and Comparative Examples 1 to 4.

From the comparison of the evaluation results between Examples 1 to 5 and Comparative Examples 1 to 4, a laminated non-woven fabric in which two or more layers of non-woven fabric are bonded by fusion is contained, and the pattern formed by the fused portion forms a repeating pattern. The average value of the area of one pattern element constituting the handle is 1 to 4.2 mm ² , the maximum value of the shortest distance between adjacent handle elements is 10 mm or less, and the blockage rate of the fused portion is set to one handle element. It can be seen that the filter medium having a value divided by the average value of the area of 0.8 to 1.2% / mm ² has an excellent balance between pressure loss and adhesive strength, and is excellent in post-workability.

From the comparison between Example 2 and Comparative Example 2, it can be seen that when the average value of the area of one handle element is less than 1 mm ² , the fused portion is peeled off by the pleating process and the adhesive strength is inferior.

From the comparison of the evaluation results of Example 4 and Comparative Example 4, it can be seen that when the average value of the area of one handle element exceeds 4.2 mm ² , the fused portion is large and the pressure loss is high.

From the comparison of the evaluation results between Example 4 and Comparative Example 1, when the value obtained by dividing the blockage rate by the average value of the area of one handle element is less than 0.8% / mm ² , the patterns are sparse and the adjacent patterns are adjacent to each other. The maximum value of the shortest distance between the elements became more than 10 mm, and in the post-processing, the filter medium was lifted and turned over, and the defect rate was high.

From the comparison of the evaluation results between Example 3 and Comparative Example 3, when the value obtained by dividing the blockage rate by the average value of the area of one handle element is more than 1.2% / mm ² , the handle becomes dense and the pressure loss occurs. It turns out that it will be higher.

From the comparison of the evaluation results of Example 1 and Example 5, it can be seen that tilting the handle suppresses the floating and curling of the laminated non-woven fabric, improves the post-workability, and is more preferable.

<Filter material A>
[Manufacturing of bonded non-woven fabric: bonding of charged non-woven fabric and protective non-woven fabric]
(Ultrasonic bonded non-woven fabric 1)
Permanently charged 15 g / m ² polypropylene spunbonded non-woven fabric (protective non-woven fabric) and 25 g / m ² polypropylene melt-blown non-woven fabric, 0.3-0.5 μm counting method collection under 5.3 cm / sec conditions. Using a non-woven fabric (charged non-woven fabric) having an efficiency of 99.97% or more, laminating processing was performed by ultrasonic fusion to prepare an ultrasonic laminated non-woven fabric 1.

In the ultrasonic bonding process, the invisible equilateral triangles ABC are arranged so that they do not overlap each other, and the midpoints of each side of the equilateral triangle ABC and the vertices of adjacent equilateral triangles coincide with each other. (Fig. 1), a rectangular pattern element exists on the line connecting the center of gravity G of the equilateral triangle ABC and the vertices A, B, and C, and the line and the long side of the rectangle are parallel to each other. Moreover, the pattern elements were arranged so that the midpoint of the line and the center of gravity of the rectangle coincided with each other (FIG. 2). The length of one side of the invisible equilateral triangle ABC is 22 mm, the long side of the rectangle is 2 mm, and the short side is 0.5 mm.

(Ultrasonic bonded non-woven fabric 2)
An ultrasonic laminated non-woven fabric 2 which is the same as the ultrasonic bonded nonwoven fabric 1 except that the length of one side of the invisible equilateral triangle ABC is 20 mm was obtained.

(Ultrasonic bonded non-woven fabric 3)
An ultrasonic laminated non-woven fabric 3 which is the same as the ultrasonic bonded nonwoven fabric 1 except that the length of one side of the invisible equilateral triangle ABC is 25 mm was obtained.

(Ultrasonic bonded non-woven fabric 4)
An ultrasonic bonded non-woven fabric 4 which is the same as the ultrasonic bonded non-woven fabric 2 except that the size of the handle element is 1 mm × 3 mm was obtained.

..
(Ultrasonic bonded non-woven fabric 5)
An ultrasonic bonded non-woven fabric 5 which is the same as the ultrasonic bonded non-woven fabric 2 except that the size of the handle element is 0.5 mm × 1 mm was obtained.

(Ultrasonic bonded non-woven fabric 6)
The ultrasonic bonded non-woven fabric 6 which is the same as the ultrasonic bonded non-woven fabric 1 except that the size of the handle element is 1.2 mm × 3.5 mm and the length of one side of the invisible equilateral triangle ABC is 24 mm. Obtained.

(Ultrasonic bonded non-woven fabric 7)
An ultrasonic laminated non-woven fabric 7 which is the same as the ultrasonic bonded nonwoven fabric 4 except that the length of one side of the invisible equilateral triangle ABC is 19 mm was obtained.

(Ultrasonic bonded non-woven fabric 8)
An ultrasonic bonded non-woven fabric 8 which is the same as the ultrasonic bonded non-woven fabric 6 except that the size of the handle element is 1.2 mm × 4 mm was obtained.

Example 11
100 parts by mass of aldehyde adsorbent (granular activated charcoal impregnated with 4-amino-1,2,4-triazole and ferric chloride) on a non-woven fabric for a support (60 g / m ² polyester spunbonded non-woven fabric) 300 g / m ² of a mixed powder mixed with 50 parts by mass of a thermoplastic adhesive (ethylene vinyl acetate copolymer powder having a softening point of 100 ° C.) was sprayed, and an infrared heater having a surface temperature of 150 ° C. was sprayed from the spraying side. Then, after the thermoplastic adhesive has been plasticized, the heating is stopped, and the non-woven fabric for the support is immediately laminated so that the charged non-woven fabric side of the ultrasonically bonded non-woven fabric 1 is in contact with the adsorbent spraying side. The filter medium of Example 11 was obtained by sandwiching it between the rotating rolls of the book, applying pressure, and integrating by adhesion.

Example 12
The filter medium of Example 12 was obtained by the same method as in Example 11 except that the ultrasonic-bonded nonwoven fabric 1 used in Example 11 was replaced with the ultrasonic-bonded nonwoven fabric 2.

Example 13
The filter medium of Example 13 was obtained by the same method as in Example 11 except that the ultrasonic-bonded nonwoven fabric 1 used in Example 11 was replaced with the ultrasonic-bonded nonwoven fabric 4.

Example 14
The filter medium of Example 14 was obtained by the same method as in Example 11 except that the ultrasonic-bonded nonwoven fabric 1 used in Example 11 was replaced with the ultrasonic-bonded nonwoven fabric 6.

Comparative Example 11
The filter medium of Comparative Example 11 was obtained by the same method as in Example 11 except that the ultrasonic-bonded nonwoven fabric 1 used in Example 11 was replaced with the ultrasonic-bonded nonwoven fabric 3.

Comparative Example 12
The filter medium of Comparative Example 12 was obtained by the same method as in Example 11 except that the ultrasonic-bonded nonwoven fabric 1 used in Example 11 was replaced with the ultrasonic-bonded nonwoven fabric 5.

Comparative Example 13
The filter medium of Comparative Example 13 was obtained by the same method as in Example 11 except that the ultrasonic-bonded nonwoven fabric 1 used in Example 11 was replaced with the ultrasonic-bonded nonwoven fabric 7.

Comparative Example 14
The filter medium of Comparative Example 14 was obtained by the same method as in Example 11 except that the ultrasonic-bonded nonwoven fabric 1 used in Example 11 was replaced with the ultrasonic-bonded nonwoven fabric 8.

Table 2 shows the evaluation results of Examples 11 to 14 and Comparative Examples 11 to 14.

From the comparison of the evaluation results between Examples 11 to 14 and Comparative Examples 11 to 14, a laminated non-woven fabric in which two or more layers of non-woven fabric are bonded by fusion is contained, and the pattern formed by the fused portion forms a repeating pattern. The average value of the area of one pattern element constituting the handle is 1 to 4.2 mm ² , the maximum value of the shortest distance between adjacent handle elements is 10 mm or less, and the blockage rate of the fused portion is set to one handle element. A filter medium having a value divided by the average value of the area of 0.8 to 1.2% / mm ² has an excellent balance between pressure loss and adhesive strength, as well as excellent dust collection efficiency and deodorizing performance, and a low defect rate. It turns out that.

From the comparison between Example 12 and Comparative Example 12, it can be seen that when the average value of the area of one handle element is less than 1 mm ² , the fused portion is peeled off by the pleating process and the adhesive strength is inferior.

From the comparison of the evaluation results of Example 14 and Comparative Example 14, it can be seen that when the average value of the area of one handle element exceeds 4.2 mm ² , the fused portion is large and the pressure loss is high.

From the comparison of the evaluation results between Example 14 and Comparative Example 11, when the value obtained by dividing the blockage rate by the average value of the area of one handle element is less than 0.8% / mm ² , the patterns are sparse and the adjacent patterns are adjacent to each other. It can be seen that the maximum value of the shortest distance between the elements is more than 10 mm, the filter medium is lifted or turned over in the post-processing, and the defect rate is high.

From the comparison of the evaluation results between Example 13 and Comparative Example 13, when the value obtained by dividing the blockage rate by the average value of the area of one handle element is more than 1.2% / mm ² , the handle becomes dense and the pressure loss occurs. It turns out that it will be higher.

<Filter material B>
Example 21
Non-woven fabric for support (chemical bond non-woven fabric composed of polyester fiber and acrylic resin with a grain of 50 g / m ² ) and polypropylene melt-blow non-woven fabric with a grain of 30 g / m ² are permanently charged and processed under the condition of 5.3 cm / sec. 0.3-0.5 μm counting method Using a charged non-woven fabric with a collection efficiency of 99.97% or more, laminating processing (ultrasonic laminating processing) by ultrasonic fusion is performed to obtain a laminated non-woven fabric. An air filter filter medium of Example 21 was obtained.

Example 22
The filter medium of Example 22 was obtained in the same manner as in Example 21 except that the length of one side of the invisible equilateral triangle ABC was 20 mm.

Comparative Example 21
The air filter filter medium of Comparative Example 21 was obtained in the same manner as in Example 21 except that the length of one side of the invisible equilateral triangle ABC was 25 mm.

Comparative Example 22
The filter medium of Comparative Example 22 was obtained in the same manner as in Example 22 except that the size of the handle element was 0.5 mm × 1 mm.

Example 23
The filter medium of Example 23 was obtained in the same manner as in Example 21 except that the size of the handle element was 1.2 mm × 3.5 mm and the length of one side of the invisible equilateral triangle ABC was 24 mm.

Comparative Example 23
The filter medium of Comparative Example 23 was obtained in the same manner as in Example 21 except that the size of the handle element was 1 mm × 3 mm and the length of one side of the invisible equilateral triangle ABC was 19 mm.

Comparative Example 24
The filter medium of Comparative Example 24 was obtained in the same manner as in Example 23 except that the size of the handle element was 1.2 mm × 4 mm.

Example 24
The filter medium of Example 24 was obtained in the same manner as in Example 21 except that the non-woven fabric for the support was a chemical-bonded nonwoven fabric composed of a polyester fiber having a basis weight of 20 g / m ² and an acrylic resin.

Example 25
The filter medium of Example 25 was obtained in the same manner as in Example 21 except that the non-woven fabric for the support was a chemical-bonded nonwoven fabric composed of polyester fiber and acrylic resin having a basis weight of 120 g / m ² .

Example 26
The filter medium of Example 26 was obtained in the same manner as in Example 21 except that the non-woven fabric for the support was a thermal bond nonwoven fabric composed of polyester fibers having a basis weight of 50 g / m ² and polyester binder fibers.

Example 27
A polypropylene melt-blown non-woven fabric with a texture of 5 g / m ² is permanently charged, and the collection efficiency is 99.97% or more by the 0.3-0.5 μm counting method under the condition of 5.3 cm / sec. Same as in Example 21 except that it is a non-woven fabric.

Example 28
The charged non-woven fabric is a polypropylene melt-blown non-woven fabric with a grain size of 60 g / m ² and is permanently charged. The charging efficiency is 99.97% or more by the 0.3-0.5 μm counting method under the condition of 5.3 cm / sec. The filter medium of Example 28 was obtained in the same manner as in Example 21 except that it was a non-woven fabric.

The evaluation results of Examples 21 to 28 and Comparative Examples 21 to 24 are shown in Tables 3 and 4.

From the comparison of the evaluation results between Examples 21 to 28 and Comparative Examples 21 to 24, a laminated non-woven fabric in which two or more layers of non-woven fabric are bonded by fusion is contained, and the pattern formed by the fused portion forms a repeating pattern. The average value of the area of one pattern element constituting the handle is 1 to 4.2 mm ² , the maximum value of the shortest distance between adjacent handle elements is 10 mm or less, and the blockage rate of the fused portion is set to one handle element. A filter medium having a value divided by the average value of the area of 0.8 to 1.2% / mm ² is a filter medium having an excellent balance between pressure loss and adhesive strength, excellent dust collection efficiency, and a low defect rate. I understand.

From the comparison of the evaluation results between Example 21 and Comparative Example 21, when the value obtained by dividing the blockage rate by the average value of the area of one handle element is less than 0.8% / mm ² , the patterns are sparse and the adjacent patterns are adjacent to each other. It can be seen that the maximum value of the shortest distance between the elements is more than 10 mm, the filter medium is lifted or turned over in the post-processing, and the defect rate is high.

From the comparison between Example 22 and Comparative Example 22, it can be seen that when the average value of the area of one handle element is less than 1 mm ² , the fused portion is peeled off by the pleating process and the adhesive strength is inferior.

From the comparison of the evaluation results between Example 22 and Comparative Example 23, when the value obtained by dividing the blockage rate by the average value of the area of one handle element is more than 1.2% / mm ² , the handle becomes dense and the pressure loss occurs. It turns out that it will be higher.

From the comparison of the evaluation results of Example 23 and Comparative Example 24, it can be seen that when the average value of the area of one handle element exceeds 4.2 mm ² , the fused portion is large and the pressure loss is high.

Example 31
A chemical bond non-woven fabric having a grain size of 50 g / m ² composed of polyester fiber and acrylic resin was used as the non-woven fabric for the support, and an aldehyde adsorbent (aluminum silicate modified with an amino compound, average particles) was used for the non-woven fabric for the support. For supports with a diameter of 5 μm) impregnated with a content of 10 g / m ² and a styrene-acrylic resin emulsion binder with a content of 4 g / m ² and dried at 120 ° C. to carry an aldehyde adsorbent. A non-woven fabric was produced. Next, the non-woven fabric for the support and the melt-blown non-woven fabric made of polypropylene of 30 g / m ² were permanently charged, and the collection efficiency of 0.3 to 0.5 μm counting method under the condition of 5.3 cm / sec was 99.97%. Using the above-mentioned charged non-woven fabric, laminating processing was performed by ultrasonic fusion to obtain the filter medium of Example 31.

In the bonding process by ultrasonic fusion, the invisible equilateral triangles ABC are arranged so that they do not overlap with each other, and the midpoint of each side of the equilateral triangle ABC and the vertices of the adjacent equilateral triangles are aligned. Arranged so as to match (FIG. 1), a rectangular pattern element exists on a line connecting the center of gravity G of the equilateral triangle ABC and each of the vertices A, B, and C, and the line and the long side of the rectangle are parallel to each other. And the pattern elements were arranged so that the midpoint of the line and the center of gravity of the rectangle coincided with each other (FIG. 2). The length of one side of the invisible equilateral triangle ABC is 22 mm, the long side of the rectangle is 2 mm, and the short side is 0.5 mm.

Example 32
The filter medium of Example 32 was obtained in the same manner as in Example 31 except that the length of one side of the invisible equilateral triangle ABC was 20 mm.

Comparative Example 31
The filter medium of Comparative Example 31 was obtained in the same manner as in Example 31 except that the length of one side of the invisible equilateral triangle ABC was 25 mm.

Comparative Example 32
The filter medium of Comparative Example 32 was obtained in the same manner as in Example 32 except that the size of the handle element was 0.5 mm × 1 mm.

Example 33
The filter medium of Example 33 was obtained in the same manner as in Example 31 except that the size of the handle element was 1.2 mm × 3.5 mm and the length of one side of the invisible equilateral triangle ABC was 24 mm.

Comparative Example 33
The filter medium of Comparative Example 33 was obtained in the same manner as in Example 31 except that the size of the handle element was 1 mm × 3 mm and the length of one side of the invisible equilateral triangle ABC was 19 mm.

Comparative Example 34
The filter medium of Comparative Example 34 was obtained in the same manner as in Example 33 except that the size of the handle element was 1.2 mm × 4 mm.

Example 34
The filter medium of Example 34 was obtained in the same manner as in Example 31 except that the nonwoven fabric for the support was a chemical-bonded nonwoven fabric having a basis weight of 25 g / m ² composed of polyester fiber and acrylic resin.

Example 35
The filter medium of Example 35 was obtained in the same manner as in Example 31 except that the non-woven fabric for the support was a 130 g / m ² chemical-bonded nonwoven fabric composed of polyester fiber and acrylic resin.

Example 36
The filter medium of Example 36 was obtained in the same manner as in Example 31 except that the average particle size of the aldehyde adsorbent was 1 μm.

Example 37
The filter medium of Example 37 was obtained in the same manner as in Example 31 except that the average particle size of the aldehyde adsorbent was 50 μm.

The evaluation results of Examples 31 to 37 and Comparative Examples 31 to 34 are shown in Tables 5 and 6.

From the comparison of the evaluation results between Examples 31 to 37 and Comparative Examples 31 to 34, a laminated non-woven fabric in which two or more layers of non-woven fabric are bonded by fusion is contained, and the pattern formed by the fused portion forms a repeating pattern. The average value of the area of one pattern element constituting the handle is 1 to 4.2 mm ² , the maximum value of the shortest distance between adjacent handle elements is 10 mm or less, and the blockage rate of the fused portion is set to one handle element. A filter medium having a value divided by the average value of the area of 0.8 to 1.2% / mm ² has an excellent balance between pressure loss and adhesive strength, as well as excellent dust collection efficiency and deodorizing performance, and a low defect rate. It turns out that.

From the comparison between Example 32 and Comparative Example 32, it can be seen that when the average value of the area of one handle element is less than 1 mm ² , peeling of the fused portion occurs in the post-processing and the adhesive strength is inferior.

From the comparison of the evaluation results of Example 33 and Comparative Example 34, it can be seen that when the average value of the area of one handle element exceeds 4.2 mm ² , the fused portion is large and the pressure loss is high.

From the comparison of the evaluation results between Example 33 and Comparative Example 31, when the value obtained by dividing the blockage rate by the average value of the area of one handle element is less than 0.8% / mm ² , the patterns are sparse and the adjacent patterns are adjacent to each other. It can be seen that the maximum value of the shortest distance between the elements is more than 10 mm, the filter medium is lifted or turned over in the post-processing, and the defect rate is high.

From the comparison of the evaluation results between Example 32 and Comparative Example 33, when the value obtained by dividing the blockage rate by the average value of the area of one handle element is more than 1.2% / mm ² , the handle becomes dense and the pressure loss occurs. It turns out that it will be higher.

Example 41
A chemical bond non-woven fabric having a grain size of 50 g / m ² composed of polyester fiber and acrylic resin is used as the non-woven fabric for the support, and the non-woven fabric for the support contains powdered activated carbon (adsorbent, coconut shell) having a content of 12 g / m ^2. activated carbon, the accumulated volume percentage D ₅₀ a 30 [mu] m), styrene content of 4g / m ² - acrylic resin emulsion binder was impregnated coated, and dried at 120 ° C., to produce a support-body nonwoven fabric carrying an adsorbent ..

Next, the non-woven fabric for the support and the melt-blown non-woven fabric made of polypropylene of 30 g / m ² were permanently charged, and the collection efficiency of 0.3 to 0.5 μm counting method under the condition of 5.3 cm / sec was 99.97% or more. The filter medium of Example 41 was obtained by laminating by ultrasonic fusion using the charged non-woven fabric.

Example 42
The filter medium of Example 42 was obtained in the same manner as in Example 41 except that the length of one side of the invisible equilateral triangle ABC was 20 mm.

Comparative Example 41
The filter medium of Comparative Example 41 was obtained in the same manner as in Example 41 except that the length of one side of the invisible equilateral triangle ABC was 25 mm.

Comparative Example 42
The filter medium of Comparative Example 42 was obtained in the same manner as in Example 42 except that the size of the handle element was 0.5 mm × 1 mm.

Example 43
The filter medium of Example 43 was obtained in the same manner as in Example 41 except that the size of the handle element was 1.2 mm × 3.5 mm and the length of one side of the invisible equilateral triangle ABC was 24 mm.

Comparative Example 43
The filter medium of Comparative Example 43 was obtained in the same manner as in Example 41 except that the size of the handle element was 1 mm × 3 mm and the length of one side of the invisible equilateral triangle ABC was 19 mm.

Comparative Example 44
The filter medium of Comparative Example 44 was obtained in the same manner as in Example 43 except that the size of the handle element was 1.2 mm × 4 mm.

Table 7 shows the evaluation results of Examples 41 to 43 and Comparative Examples 41 to 44.

From the comparison of the evaluation results between Examples 41 to 43 and Comparative Examples 41 to 44, a laminated non-woven fabric in which two or more layers of non-woven fabric are bonded by fusion is contained, and the pattern formed by the fused portion forms a repeating pattern. The average value of the area of one pattern element constituting the handle is 1 to 4.2 mm ² , the maximum value of the shortest distance between adjacent handle elements is 10 mm or less, and the blockage rate of the fused portion is set to one handle element. A filter medium having a value divided by the average area value of 0.8 to 1.2% / mm ² has an excellent balance between pressure loss and adhesive strength, as well as excellent dust collection performance and deodorization performance, and a low defect rate. It turns out that.

From the comparison between Example 42 and Comparative Example 42, it can be seen that when the average value of the area of one handle element is less than 1 mm ² , the fused portion is peeled off by the pleating process and the adhesive strength is inferior.

From the comparison of the evaluation results of Example 43 and Comparative Example 44, it can be seen that when the average value of the area of one handle element exceeds 4.2 mm ² , the fused portion is large and the pressure loss is high.

From the comparison of the evaluation results between Example 43 and Comparative Example 41, when the value obtained by dividing the blockage rate by the average value of the area of one handle element is less than 0.8% / mm ² , the patterns are sparse and the adjacent patterns are adjacent to each other. It can be seen that the maximum value of the shortest distance between the elements is more than 10 mm, the filter medium is lifted and turned over, the defect rate is high, and the post-workability is inferior.

From the comparison of the evaluation results between Example 42 and Comparative Example 43, when the value obtained by dividing the blockage rate by the average value of the area of one handle element is more than 1.2% / mm ² , the handle becomes dense and the pressure loss occurs. It turns out that it will be higher.

<Filter material D>
Example 51
As a charged non-woven fabric, a 30 g / m ² polypropylene melt-blown non-woven fabric is permanently charged, and the dust collection efficiency of 0.3 to 0.5 μm under the condition of 5.3 cm / sec is 99.97% or more. Was used.

As the protective non-woven fabric, a 15 g / m ² polypropylene spunbonded non-woven fabric was used.

As the non-woven fabric for the support, a chemical-bonded non-woven fabric having a basis weight of 50 g / m ² composed of polyester fiber and acrylic resin was used.

After laminating so as to form a three-layer structure of a protective non-woven fabric, a charged non-woven fabric, and a non-woven fabric for a support, a laminating process was performed by ultrasonic fusion to obtain a filter medium of Example 51.

Example 52
The filter medium of Example 52 was obtained in the same manner as in Example 51 except that the length of one side of the invisible equilateral triangle ABC was 20 mm.

Comparative Example 51
A filter medium of Comparative Example 51 was obtained in the same manner as in Example 51 except that the length of one side of the invisible equilateral triangle ABC was 25 mm.

Comparative Example 52
The filter medium of Comparative Example 52 was obtained in the same manner as in Example 52 except that the size of the handle element was 0.5 mm × 1 mm.

Example 53
The filter medium of Example 53 was obtained in the same manner as in Example 51 except that the size of the handle element was 1.2 mm × 3.5 mm and the length of one side of the invisible equilateral triangle ABC was 24 mm.

Comparative Example 53
The filter medium of Comparative Example 53 was obtained in the same manner as in Example 51 except that the size of the handle element was 1 mm × 3 mm and the length of one side of the invisible equilateral triangle ABC was 19 mm.

Comparative Example 54
The filter medium of Comparative Example 54 was obtained in the same manner as in Example 53 except that the size of the handle element was 1.2 mm × 4 mm.

Table 8 shows the evaluation results of Examples 51 to 53 and Comparative Examples 51 to 54.

From the comparison of the evaluation results between Examples 51 to 53 and Comparative Examples 51 to 54, a laminated non-woven fabric in which two or more layers of non-woven fabric are bonded by fusion is contained, and the pattern formed by the fused portion forms a repeating pattern. The average value of the area of one pattern element constituting the handle is 1 to 4.2 mm ² , the maximum value of the shortest distance between adjacent handle elements is 10 mm or less, and the blockage rate of the fused portion is set to one handle element. The filter medium for air filters whose value divided by the average value of the area is 0.8 to 1.2% / mm ² has low pressure loss, sufficient adhesive strength at the fused portion, and suppresses the occurrence of floating and curling. It can be seen that the filter medium is excellent in dust collection performance, does not easily deteriorate in dust collection performance after repeated washing with water, and has excellent post-workability.

From the comparison between Example 52 and Comparative Example 52, it can be seen that when the average value of the area of one handle element is less than 1 mm ² , peeling of the fused portion occurs and the adhesive strength is inferior.

From the comparison of the evaluation results of Example 53 and Comparative Example 54, it can be seen that when the average value of the area of one handle element exceeds 4.2 mm ² , the fused portion is large and the pressure loss is high.

From the comparison of the evaluation results between Example 53 and Comparative Example 51, when the value obtained by dividing the blockage rate by the average value of the area of one handle element is less than 0.8% / mm ² , the patterns are sparse and the adjacent patterns are adjacent to each other. It can be seen that the maximum value of the shortest distance between the elements is more than 10 mm, the filter medium is lifted and turned over, the defect rate is high, and the post-workability is inferior.

From the comparison of the evaluation results between Example 52 and Comparative Example 53, when the value obtained by dividing the blockage rate by the average value of the area of one handle element is more than 1.2% / mm ² , the handle becomes dense and the pressure loss occurs. It turns out that it will be higher.

The present invention is used as a filter medium for an air filter used in air conditioning equipment and the like.

Claims

A filter medium for an air filter made of a laminated non-woven fabric in which two or more layers of non-woven fabric are bonded, and a plurality of pattern elements formed in the shape of the fused portion by fusing the above-mentioned bonding are formed as a set. The pattern is formed to show a repeating pattern, the area of one pattern element is 1 to 4.2 mm 2 on average, the shortest distance between adjacent pattern elements is 10 mm or less, and the pattern element is formed. The value obtained by dividing the blockage rate (percentage) of the fused portion corresponding to the ratio of the total area of the pattern elements included in the repeating pattern to the area of the repeating pattern by the average value of the area of one pattern element is 0.8 to A filter medium for an air filter characterized by being 1.2% / mm 2 .
The pattern of the repeating pattern formed by the pattern element is such that the invisible equilateral triangle ABC having a side of 20 to 24 mm coincides with the midpoint of each side of the equilateral triangle ABC and each vertex of the equilateral triangle ABC adjacent to each side. As described above, in the invisible repeating pattern arranged so as not to overlap each other in the same direction, the long side is 2 to 3 mm and the short side is on the straight line connecting the center of gravity G of the equilateral triangle ABC and the respective vertices A, B, and C. A rectangular handle element having a side of 0.5 to 1 mm is formed by being present so that the straight line and the long side of the rectangle are parallel to each other and the midpoint of the straight line and the center of gravity of the rectangle coincide with each other. The filter medium for an air filter according to claim 1.
The air filter filter medium according to claim 2, wherein a straight line connecting the centers of gravity G of two adjacent equilateral triangles ABC forms a minimum angle of 5 to 25 ° with respect to the flow direction of the filter medium processing.
Claims 1 to 3 that the laminated non-woven fabric is a laminated non-woven fabric in which a charged non-woven fabric and a protective non-woven fabric are bonded, and an adsorbent is sealed between the support non-woven fabric and the bonded non-woven fabric by a thermoplastic adhesive. The filter medium for the air filter described in any of the above.
The filter medium for an air filter according to any one of claims 1 to 3, wherein the laminated non-woven fabric is a laminated non-woven fabric in which a non-woven fabric for a support and a charged non-woven fabric are bonded together.
The filter medium for an air filter according to claim 5, wherein the non-woven fabric for the support carries an adsorbent.
The filter medium for an air filter according to any one of claims 1 to 3, wherein the laminated non-woven fabric is a laminated non-woven fabric in which a charged non-woven fabric, a protective non-woven fabric, and a non-woven fabric for a support are bonded, and the protective non-woven fabric is arranged on the side in contact with the outside air. ..