Nonwoven fabric laminate and filter

Abstract

The present invention provides a nonwoven fabric laminate having excellent pleat setting properties and high rigidity.　A nonwoven fabric laminate according to the present invention has a laminate structure in which at least two types of nonwoven fabric are laminated, granules having an aspect ratio of not less than 3 are sandwiched between layers of the nonwoven fabric, and substrate layers are bonded together via a binder.

Description

Nonwoven fabric laminate and filter

[0001] The present invention relates to a nonwoven fabric laminate and a filter using the same.

[0002] In recent years, in the filters for air conditioning, air conditioners, automobiles, etc., the demand for high performance and low cost of filter material has been increasing, and many studies have been made on filter material that can achieve both dust removal performance and deodorization performance (for example, see Patent Documents 1 to 3). As further performance improvement, the demand for low pressure loss of pleated filters has also been increasing.

[0003] JP-A-11-5058, JP-A-3-98642, JP-A-2001-218824

[0004] The filters currently used in air purifiers, vacuum cleaners, etc. have low rigidity and poor pleat setting properties, which leads to increased airflow resistance of the filter during high winds, making it difficult to further reduce energy consumption.

[0005] In view of the above problems, an object of the present invention is to provide a nonwoven fabric laminate having good pleat setting properties.

[0006] As a result of extensive investigations, the present inventors have found that the above problems can be solved by the following means, and have arrived at the present invention.

[0007] 1. A nonwoven fabric laminate in which a plurality of nonwoven fabrics are laminated, characterized in that particulate matter having an aspect ratio of 3 or more is bonded between at least one of the nonwoven fabric layers with a binder, and the nonwoven fabric laminate has a stiffness of 500 to 1500 mg. 2. The basis weight of the particulate matter is 1.5 to 150 g / m ２ 2. The nonwoven fabric laminate according to claim 1, wherein the particulate matter has an average particle size of 50 to 800 μm. 3. The nonwoven fabric laminate according to claim 1 or 2, wherein the particulate matter has an average particle size of 50 to 800 μm. 4. The nonwoven fabric laminate according to any one of claims 1 to 3, wherein the binder has an average particle size before melting equal to or greater than the average particle size of the particulate matter. 5. A filter using the nonwoven fabric laminate according to any one of claims 1 to 4.

[0008] The filter medium of the present invention has high rigidity and good pleat setting properties, and therefore, a filter using the filter medium of the present invention has low airflow resistance at high airflow rates.

[0009] The present invention will be described in detail below. The nonwoven fabric laminate of the present invention comprises a plurality of nonwoven fabrics laminated together, and particulate matter having an aspect ratio of 3 or more is bonded between at least one of the nonwoven fabric layers with a binder.

[0010] In this specification, the aspect ratio refers to the ratio of the major axis to the minor axis. The aspect ratio can be determined, for example, by observing the granular material with a scanning electron microscope (SEM). For example, it can be calculated by averaging the ratio of the maximum diameter to the minimum diameter of 50 randomly selected granular materials. A larger aspect ratio indicates a flatter shape. The granular material used in this embodiment has an aspect ratio of 3 or more. The aspect ratio of the granular material is preferably 3.5 or more, more preferably 4 or more. If the aspect ratio is less than 3, the rigidity of the nonwoven fabric laminate is insufficient, and when the nonwoven fabric laminate is used in a filter, the setability during pleating is poor. An aspect ratio of 3 or more can improve the rigidity of the nonwoven fabric laminate and improve the setability during pleating when the nonwoven fabric laminate is used in a filter. The aspect ratio of the granular material may be, for example, 12 or less.

[0011] The nonwoven fabric laminate preferably has a rigidity of 500 to 1500 mg. The rigidity of the nonwoven fabric laminate is more preferably 550 mg or more, even more preferably 600 mg or more, particularly preferably 800 mg or more, and is more preferably 1400 mg or less, and even more preferably 1300 mg or less. Within this range, when the nonwoven fabric laminate is used in a filter, the pleat setting ability is improved. The rigidity of the nonwoven fabric laminate can be obtained by measuring the bending resistance in the machine direction (MD direction) of the manufacturing machine for the nonwoven fabric laminate in accordance with JIS L-1096 Method A (Gurley method).

[0012] The nonwoven fabric used in the nonwoven fabric laminate of the present invention is a fiber structure containing fibers such as polyolefin fibers, polyester fibers, polyamide fibers, and polyurethane fibers.

[0013] The material of the fibers of the nonwoven fabric used in the nonwoven fabric laminate of the present invention is not particularly limited, and materials such as polyolefin resins, polyester resins, cellulose resins, polyamide resins, polyurethane resins, acrylic resins, polyvinyl alcohol resins, and polycarbonate resins can be used.

[0014] In the nonwoven fabric laminate of the present invention, the average fiber diameter of the fibers constituting the nonwoven fabric (upstream layer) on the upstream side during air purification is preferably 1 to 100 μm, more preferably 5 to 50 μm. Because the upstream layer is the inflow surface of the air to be treated, if the average fiber diameter of the constituent fibers is less than 1 μm, the gaps between the fibers will also be narrow, causing dust in the air to accumulate on the nonwoven fabric and a sudden increase in airflow resistance. If the average fiber diameter of the constituent fibers is greater than 100 μm, particulate matter will fly out or fall off, especially during pleating.

[0015] The color tone of the fibers that make up the nonwoven fabric on the upstream side is preferably a light color that allows good visibility of dust in the air, and white or fluorescent colors are more preferable. If the color is dark, it will be difficult to detect the accumulation of dust components such as exhaust gas and dust in the air, and there is a risk that the filter will not be replaced even if a large amount of dust has accumulated and become clogged.

[0016] On the other hand, in the nonwoven fabric laminate of the present invention, the average fiber diameter of the fibers constituting the downstream nonwoven fabric (downstream layer) during air purification is not particularly limited, but is preferably 10 to 30 μm in consideration of the shedding of particulate matter. If the average fiber diameter of the constituent fibers is less than 10 μm, the airflow resistance will be high, and if it is more than 30 μm, particulate matter will fall off.

[0017] The packing density of the nonwoven fabric used in the nonwoven fabric laminate of the present invention is preferably 0.05 g / cc or more. If the packing density is lower than 0.05 g / cc, heat setting during pleating is ineffective, making it difficult to maintain the pleated shape. A packing density of 0.15 g / cc or more is more preferred.

[0018] The nonwoven fabric used in the nonwoven fabric laminate of the present invention preferably has a thickness of 0.1 to 3.0 mm. If the thickness is less than 0.1 mm, there is a risk of activated carbon falling off, taking into account the unevenness of the area weight. If the thickness is more than 3.0 mm, the thickness of the entire filter material is too large, and when it is made into a pleated unit, the structural resistance becomes large, resulting in the airflow resistance of the entire unit becoming too high, which is problematic in practical use.

[0019] The nonwoven fabric used in the nonwoven fabric laminate of the present invention has a basis weight of 15 to 100 g / m ２ It is preferable that the density is 20 to 80 g / m ２ More preferably, the basis weight is 15 g / m ２ If the weight is less than 100 g / m, the granular material and thermoplastic resin will be removed. ２ If the thickness exceeds 100%, the sheet thickness becomes large, and the structural resistance when made into a pleated unit becomes large.

[0020] The material of the nonwoven fabric used in the nonwoven fabric laminate of the present invention is not particularly limited, and materials such as polyolefin resins, polyester resins, cellulose resins, polyamide resins, polyurethane resins, acrylic resins, polyvinyl alcohol resins, polycarbonate resins, etc. Among these, it is preferable to use core-sheath type composite fibers in which a low-melting point component is used as the sheath component and a high-melting point component is used as the core component, because the sheath component melts during the heating process to form a sheet, as described below, and the bonding strength with the activated carbon is increased.

[0021] It is also possible to use electrically charged nonwoven fabrics, so-called electret sheets, which can enhance the removal effect of submicron particles such as tobacco smoke particles, carbon particles, and sea salt particles.The use of electret sheets prevents dust and other particles from penetrating between the layers of the nonwoven fabric and clogging the pores of particulate matter, thereby extending the life of the filter.

[0022] The fiber orientation of the nonwoven fabric used in the nonwoven fabric laminate of the present invention is not particularly limited, and the nonwoven fabric may be, for example, random, cross, or parallel.

[0023] The nonwoven fabric used in the nonwoven fabric laminate of the present invention can be produced by any method, but it is particularly preferable that the upstream nonwoven fabric (upstream layer) has high rigidity and high uniformity. If the rigidity is low or the uniformity of the nonwoven fabric is poor, the pleat setting ability will be poor and the air resistance in the filter shape will be high. For nonwoven fabrics with high rigidity and uniformity, wet papermaking is most preferable.

[0024] The particulate material used in the nonwoven fabric laminate of the present invention may be inorganic materials such as activated carbon, silica gel, zeolite, and sepaolite, as well as expanded graphite, flame retardants, and organic porous materials such as styrene-divinylbenzene crosslinked materials. Activated carbon and silica gel are particularly preferred because of their extremely large specific surface area. Expanded graphite is also preferred from the standpoint of flame retardancy.

[0025] When activated carbon is used as the granular material, coconut shell-based, wood-based, coal-based, pitch-based, and other activated carbons are suitable. The greater the number of inlet pores, or so-called macropores, that can be seen by observing the surface, the better. When the number of macropores is large, even if the binder covers the surface of the activated carbon during the production of a mixed powder or granular material consisting of activated carbon and a granular binder, gas desorption from the inside of the pores during hot pressing can open up the pores capable of adsorption. Furthermore, a somewhat rough activated carbon surface reduces the fluidity of the molten binder resin, thereby preventing a decrease in adsorption performance.

[0026] In the nonwoven fabric laminate of the present invention, the particulate material may be subjected to a chemical treatment in order to improve the adsorption performance of polar substances and aldehydes. When the substances to be adsorbed are aldehyde gases, nitrogen compounds such as NOx, sulfur compounds such as SOx, or acidic polar substances such as acetic acid, examples of chemicals used in the chemical treatment include amine-based chemicals such as ethanolamine, polyethyleneimine, aniline, p-anisidine, sulfanilic acid, tetrahydro-1,4-oxazine, and hydrazide compounds. Tetrahydro-1,4-oxazine is a preferred amine-based chemical. It is relatively easy to obtain and dissolves easily in water, making it easy to apply. Other suitable chemicals include sodium hydroxide, potassium hydroxide, guanidine carbonate, guanidine phosphate, aminoguanidine sulfate, 5.5-dimethylhydantoin, benzoguanamine, 2.2-iminodiethanol, 2.2.2-nitrotriethanol, ethanolamine hydrochloride, 2-aminoethanol, 2.2-iminodiethanol hydrochloride, p-aminobenzoic acid, sodium sulfanilate, L-arginine, methylamine hydrochloride, semicarbazide hydrochloride, hydrazine, hydroquinone, hydroxylamine sulfate, permanganate, potassium carbonate, and potassium bicarbonate. When the adsorption target is a basic polar substance such as ammonia, methylamine, trimethylamine, or pyridine, suitable chemicals include phosphoric acid, citric acid, malic acid, ascorbic acid, and tartaric acid. Granules treated with these chemicals may be used alone or in combination with untreated granules.

[0027] The chemical treatment can be carried out, for example, by supporting or impregnating the chemical on the granular material. In addition to directly treating the granular material with the chemical, it is also possible to impregnate the nonwoven fabric laminate near its surface using a conventional coating method, or to impregnate the entire nonwoven fabric laminate with the chemical. In this case, it is also possible to prepare an aqueous solution of the chemical containing a thickener such as sodium alginate or polyethylene oxide, and then carry out the supporting or impregnation using this solution. This method is effective for supporting or impregnating chemicals that have low solubility in water, and is also effective in preventing the chemicals from falling off.

[0028] The granular material used in the nonwoven fabric laminate of the present invention has a basis weight of 1.5 to 150 g / m ２ The weight of the granular material is preferably 2 g / m ２ More preferably, 2.5 g / m or more ２ More preferably, 120 g / m ２ More preferably, 100 g / m or less ２ More preferably, the weight per unit area is 2 g / m or less. ２ If the nonwoven fabric laminate is used in a filter, the strength is weak and pleat setting is poor. ２ If the basis weight is higher than this, the thickness of the nonwoven fabric laminate increases significantly, the pleat setting property deteriorates, and the airflow resistance increases.

[0029] The average particle size of the granular material used in the nonwoven fabric laminate of the present invention is preferably 50 to 800 μm. The average particle size of the granular material is more preferably 100 μm or more, even more preferably 200 μm or more, and more preferably 700 μm or less, and even more preferably 600 μm or less. If the average particle size is less than 50 μm, the rigidity of the filter material will be reduced and pleat setting will be poor. On the other hand, if the average particle size is greater than 800 μm, the thickness will be increased, pleat setting will be poor, and the airflow resistance in the filter shape will also increase. The average particle size of the granular material can be the mass average diameter based on JIS K 1474 Activated Carbon Test Method.

[0030] The nonwoven fabric laminate of the present invention has a laminate structure in which at least two nonwoven fabrics are laminated together and particulate matter is bonded between at least one of the layers with a binder.

[0031] The binder used in the nonwoven fabric laminate of the present invention is preferably made of a thermoplastic resin, and examples of such thermoplastic resins include polyolefin resins, polyamide resins, polyester resins, and ethylene-acrylic copolymer resins. There are no particular limitations on the binder components, but polyolefin resins and polyester resins are preferred because they provide strong adhesion at the interface between the base layer and the binder, resulting in high peel strength.

[0032] When a thermoplastic resin is used as a binder in the nonwoven fabric laminate of the present invention, the thermoplastic resin is preferably in powder (granular) form with an average particle size of 100 to 800 μm. If the granular thermoplastic resin (granular binder) is less than 100 μm, adhesive forces due to van der Waals forces or electrostatic forces act between the granular material such as the adsorbent and the thermoplastic resin, preventing the thermoplastic resin from actively contacting the base layer, and insufficient peel strength is obtained. On the other hand, if it exceeds 800 μm, the thickness of the nonwoven fabric laminate increases, increasing the structural resistance when used as a filter, which is undesirable from a practical standpoint. Note that the above average particle size is the weight-average particle size.

[0033] The thermoplastic resin used as a binder in the nonwoven fabric laminate of the present invention is preferably in powder (granular) form, and its average particle size before heat-melting is preferably equal to or greater than the average particle size of the granules. If the average particle size is smaller than the granules, such as the adsorbent, the adhesion between the base layers will be weaker, the interlayer peel strength will decrease, and pleat setting will be poor. The average particle size of the thermoplastic resin used as a binder before heat-melting is preferably at least 1.05 times the average particle size of the granules, more preferably at least 1.10 times, and even more preferably at least 1.50 times. Having the average particle size of the thermoplastic resin used as a binder before heat-melting larger than the average particle size of the granules within the above range can improve the interlayer peel strength. The average particle size of the thermoplastic resin used as a binder before heat-melting is preferably no more than 2.20 times the average particle size of the granules, more preferably no more than 2.10 times, and even more preferably no more than 2.0 times. When the average particle size of the thermoplastic resin used as the binder before heating and melting is 2.20 times or less larger than the average particle size of the granules, the balance between the adhesive strength between layers and the air resistance is improved.

[0034] The granular binder used in the nonwoven fabric laminate of the present invention is preferably used in an amount of 10 to 80% by weight, more preferably 20 to 70% by weight, based on the granular material, because within this range, a filter medium having excellent adhesion to the base layer, pressure loss, and deodorizing performance can be obtained.

[0035] The nonwoven fabric laminate of the present invention may be constructed by including components with additional functions, such as antibacterial agents, antifungal agents, antiviral agents, and flame retardants. These components may be kneaded into the fibers or nonwoven fabric that form the substrate layer, or may be attached or supported by post-processing. For example, by including a flame retardant in the filter medium, it is possible to produce a nonwoven fabric laminate that meets the flame retardancy standards specified in FMVSS.302 and the UL flame retardancy standard.

[0036] The nonwoven fabric laminate of the present invention can be used as a filter. This filter may be combined with other components, such as a nonwoven fabric, a substrate, or a frame material. A filter using the nonwoven fabric laminate of this embodiment also falls within the scope of the present invention.

[0037] This application claims the benefit of priority based on Japanese Patent Application No. 2024-057438, filed on March 29, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-057438, filed on March 29, 2024, are incorporated herein by reference.

[0038] The present invention will be described in more detail below with reference to examples. The properties shown in the following examples and comparative examples were measured by the following methods. It should be noted that the present invention is not limited to those described in the examples.

[0039] (Pressure Loss) The nonwoven fabric laminate was placed in a duct, and air was passed through it so that the air filtration rate was 50 cm / sec. The static pressure difference between the upstream and downstream sides of the filter medium was read with a differential pressure gauge to measure the pressure loss (Pa).

[0040] (Peel Strength) The average peel strength between the upstream layer and the downstream layer was measured using a test piece having a width of 50 mm and a length of 200 mm, and the test was carried out at a tensile strength of 100 mm / min.

[0041] (Rigidity) The bending resistance in the machine direction was measured in accordance with JIS L-1096 Method A (Gurley method).

[0042] (Average particle size) The mass average particle size based on JIS K 1474 activated carbon testing method was taken as the average particle size.

[0043] (Aspect Ratio) The particle was evaluated by observing it with a scanning electron microscope (SEM). The aspect ratio was calculated by averaging the ratio of the maximum diameter to the minimum diameter of 50 randomly selected particles.

[0044] (Pleat settability) When the spread of a pleat block having a width of 180 mm and 30 ridges was 150% or more of the value calculated from product thickness x number of ridges (30) x 2, the pleat settability was judged to be poor (×), and when it was less than 150%, the pleat settability was judged to be good (◯).

[0045] Example 1 A wet-laid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon with an aspect ratio of 3 and an average particle size of 300 μm and an EVA-based resin (average particle size 350 μm, MI 75 g / 10 min, melting point 96° C.) as a thermoplastic powder resin were weighed out in a ratio of 1:1. This mixture was stirred and mixed for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), and then the mixed powder was applied to the upstream layer in a total amount of 200 g / m. ２ On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２ The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then heat-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate of Example 1.

[0046] [Example 2] A wetlaid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon and silica gel, each with an aspect ratio of 5 and an average particle size of 300 μm, and an EVA-based resin (average particle size 350 μm, MI 75 g / 10 min, melting point 96°C) as a thermoplastic powder resin, were weighed out in a ratio of 1:1:1. This mixture was stirred and mixed for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), and then the mixed powder was applied to the upstream layer in a total amount of 200 g / m. ２ On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then heat-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate of Example 2.

[0047] [Example 3] A wetlaid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon and silica gel, each with an aspect ratio of 10 and an average particle size of 300 μm, and an EVA-based resin (average particle size 350 μm, MI 75 g / 10 min, melting point 96°C) as a thermoplastic powder resin, were weighed out in a ratio of 1:1:1. This mixture was stirred and mixed for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), and then the mixed powder was applied to the upstream layer in a total amount of 200 g / m. ２ On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２ The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then heat-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate of Example 3.

[0048] Example 4 A wet-laid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon and silica gel, each having an aspect ratio of 4 and an average particle size of 300 μm, expanded graphite, and an EVA-based resin (average particle size 350 μm, MI 75 g / 10 min, melting point 96° C.) as a thermoplastic powder resin were weighed out in a ratio of 1:1:0.5:1. After stirring and mixing for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), the mixed powder was applied to the upstream layer in a total amount of 4 g / m. ２ On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２ The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then heat-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate of Example 4.

[0049] Example 5 A wet-laid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon and silica gel, each having an aspect ratio of 4 and an average particle size of 300 μm, expanded graphite, and an EVA-based resin (average particle size 350 μm, MI 75 g / 10 min, melting point 96° C.) as a thermoplastic powder resin were weighed out in a ratio of 33:33:2.5:33, respectively. After stirring and mixing for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), the mixed powder was applied to the upstream layer in a total amount of 4 g / m. ２ On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２ The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then heat-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate of Example 5.

[0050] Example 6 A wetlaid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon and silica gel, each with an aspect ratio of 2 and an average particle size of 300 μm, expanded graphite with an aspect ratio of 4, and an EVA-based thermoplastic powder resin (average particle size 350 μm, MI 75 g / 10 min, melting point 96° C.), were weighed out in a ratio of 33:33:2.5:33, respectively. After stirring and mixing for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), the mixed powder was applied to the upstream layer in a total amount of 100 g / m. ２ On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２ The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then heat-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate of Example 6.

[0051] Example 7 A wetlaid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon and silica gel, each with an aspect ratio of 4 and an average particle size of 300 μm, expanded graphite with an aspect ratio of 4, and an EVA-based resin (average particle size of 350 μm, MI 75 g / 10 min, melting point 96° C.) as a thermoplastic powder resin were weighed out in a ratio of 33:33:2.5:33, respectively. This mixture was stirred and mixed for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), and then the mixed powder was applied to the upstream layer in a total amount of 150 g / m. ２ On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２ The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then heat-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate of Example 7.

[0052] Example 8 A wetlaid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon and silica gel, each with an aspect ratio of 4 and an average particle size of 50 μm, expanded graphite with an aspect ratio of 4, and EVA resin (average particle size 100 μm, MI 75 g / 10 min, melting point 96° C.) as a thermoplastic powder resin were weighed out in a ratio of 33:33:2.5:33, respectively. After stirring and mixing for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), the mixed powder was added to the upstream layer in a total amount of 100 g / m. ２ On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２ The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then hot-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate of Example 8.

[0053] Example 9 A wetlaid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon and silica gel, each with an aspect ratio of 4 and an average particle size of 800 μm, expanded graphite with an aspect ratio of 4, and an EVA-based thermoplastic powder resin (average particle size of 850 μm, MI 75 g / 10 min, melting point 96° C.), were weighed out in a ratio of 33:33:2.5:33, respectively. This mixture was stirred and mixed for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), and then the mixed powder was applied to the upstream layer in a total amount of 100 g / m. ２ On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２ The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then hot-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate of Example 9.

[0054] Comparative Example 1 A wet-laid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon with an aspect ratio of 2 and an average particle size of 300 μm and an EVA-based resin (average particle size 350 μm, MI 75 g / 10 min, melting point 96° C.) as a thermoplastic powder resin were weighed out in a ratio of 1:1. This mixture was stirred and mixed for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), and then the mixed powder was applied to the upstream layer in a total amount of 100 g / m. ２ On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２ The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then heat-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate of Comparative Example 1.

[0055] [Comparative Example 2] A wet-laid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon with an aspect ratio of 4 and an average particle size of 300 μm and an EVA-based resin (average particle size 350 μm, MI 75 g / 10 min, melting point 96°C) as a thermoplastic powder resin were weighed out in a ratio of 1:1. This was mixed and stirred for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), and the mixed powder was then added to the upstream layer in a total amount of 1 g / m. ２On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２ The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then heat-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate for Comparative Example 2.

[0056] Comparative Example 3: A wet-laid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon with an aspect ratio of 4 and an average particle size of 300 μm and an EVA-based resin (average particle size 350 μm, MI 75 g / 10 min, melting point 96° C.) as a thermoplastic powder resin were weighed out in a ratio of 1:1. This mixture was stirred and mixed for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), and then the mixed powder was applied to the upstream layer in a total amount of 160 g / m. ２ On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２ The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then heat-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate of Comparative Example 3.

[0057] Comparative Example 4 A wet-laid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon with an aspect ratio of 4 and an average particle size of 45 μm and an EVA-based resin (average particle size 100 μm, MI 75 g / 10 min, melting point 96° C.) as a thermoplastic powder resin were weighed out in a ratio of 1:1. This mixture was stirred and mixed for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), and then the mixed powder was applied to the upstream layer in a total amount of 100 g / m. ２ On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２ The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then heat-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate of Comparative Example 4.

[0058] Comparative Example 5 A wet-laid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon with an aspect ratio of 4 and an average particle size of 850 μm and an EVA-based resin (average particle size of 900 μm, MI 75 g / 10 min, melting point 96° C.) as a thermoplastic powder resin were weighed out in a ratio of 1:1. This mixture was stirred and mixed for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), and the mixed powder was applied to the upstream layer in a total amount of 100 g / m. ２ On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２ The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then heat-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate of Comparative Example 5.

[0059] Comparative Example 6 A wet-laid nonwoven fabric was used as the upstream layer. Coconut shell activated carbon with an aspect ratio of 4 and an average particle size of 300 μm and an EVA-based resin (average particle size 250 μm, MI 75 g / 10 min, melting point 96° C.) as a thermoplastic powder resin were weighed out in a ratio of 1:1. This mixture was stirred and mixed for 15 minutes in a hoop shaker (manufactured by Kyomachi Industrial Vehicles Co., Ltd.), and then the mixed powder was applied to the upstream layer in a total amount of 100 g / m. ２ On top of that, a polyester spunbond nonwoven fabric (average 20 μm, basis weight 20 g / m) was placed. ２ The resulting laminate was sandwiched between Teflon (registered trademark) / glass belts, and then heat-pressed at 130°C for 30 seconds with a belt gap of 0.5 mm and a pressure of 100 kPa. The resulting laminate was then cooled to obtain a nonwoven fabric laminate of Comparative Example 6.

[0060] The results of Examples 1 to 9 are shown in Table 1, and the results of Comparative Examples 1 to 6 are shown in Table 2.

[0061]

[0062]

[0063] From Tables 1 and 2, it can be seen that granular materials with an aspect ratio of 3 or more are sandwiched between nonwoven fabric layers, the base material layers are bonded together via a binder, and the basis weight of the granular materials is 2 to 150 g / m ２When the average particle size is 50 to 800 μm and the particle size of the binder before melting is equal to or greater than the average particle size of the granular material, the pleat setting property is improved.

[0064] The nonwoven fabric laminate of the present invention exhibits excellent pleat setting properties and is highly useful industrially, for example, in a wide range of applications, including automobiles, air purifiers, air conditioners, copiers, printers, multi-function office automation equipment, and toilet deodorizers, making it a significant contribution to industry.

Claims

1. A nonwoven fabric laminate in which multiple nonwoven fabrics are layered, characterized in that particulate matter with an aspect ratio of 3 or more is bonded between at least one of the nonwoven fabric layers with a binder, and the nonwoven fabric laminate has a stiffness of 500 to 1500 mg.

2. The basis weight of the granular material is 1.5 to 150 g / m ２ 2. The nonwoven fabric laminate according to claim 1, wherein 3. The nonwoven fabric laminate according to claim 1, wherein the average particle size of the particulate material is 50 to 800 μm.

4. The nonwoven fabric laminate according to claim 1, wherein the average particle size of the binder before melting is equal to or greater than the average particle size of the particulate material.

5. A filter using the nonwoven fabric laminate according to any one of claims 1 to 4.

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