JP5082292B2 - Adsorbent sheet - Google Patents

Description

  The present invention relates to a filter medium for air purification having a dust removing function and a deodorizing function.

In recent years, in the fields of automobiles, household filters, and the like, there has been a rapid increase in the demand for higher functionality and diversification of filter media, and many studies have been made on air purification filter media having both a dust removal function and a deodorization function. And as these air purification filter media, a method of forming a sheet using a particulate or fibrous adsorbent and an adhesive is often employed. For example, a mixture of a granular adsorbent and a granular adhesive between substrates is used. An adsorptive filter medium formed by spraying and heat-bonding this is disclosed (for example, see Patent Document 1). Such adsorptive filter media can provide an adsorbent sheet that is low in cost and excellent in air permeability. However, since the adhesion between the adsorbent layer and the base material layer is weak, peeling easily occurs, and when external force is applied by pleating or the like, or the filter is increased. When exposed to air flow, there were practical problems such as a large dropout of the adsorbent. In order to solve such a problem, for example, an adsorbent sheet in which an adsorbent layer and a substrate are bonded using an adhesive sheet is disclosed (for example, see Patent Document 2). However, such an adsorbent sheet has a problem that the adhesive sheet impairs the air permeability and increases the air resistance, and further, the adhering surface tends to clog the dust or impedes the adsorbing performance.
Japanese Patent Laid-Open No. 11-5058 JP 2002-273123 A

The present invention has been made against the background of the above-described prior art, has sufficient adhesion between the base material layer and the adsorbing layer, has excellent pleatability, has low ventilation resistance, and high deodorization performance. An attempt is made to provide an adsorbent sheet.

As a result of intensive studies to solve the above problems, the present inventors have finally completed the present invention. That is, the present invention is (1) an adsorbent sheet containing an adsorbent and a thermoplastic resin between base material layers, wherein at least one surface of the base material layer is a nonwoven fabric subjected to needle punching and / or hydroentanglement processing. (2) The non-woven fabric according to (1) or (2) is an electret non-woven fabric, wherein the non-woven fabric according to (2) (1) is a non-woven fabric that does not contain a binder component. The adsorbent sheet according to any one of 1) to (3).

The adsorbent sheet according to the present invention has an advantage that it can provide an adsorbent sheet having strong adhesion between the base material layer and the adsorbing layer, and having low ventilation resistance and good deodorization performance.

Hereinafter, the present invention will be described in detail.
The adsorbent sheet of the present invention is an adsorbent sheet containing an adsorbent and a thermoplastic resin between base material layers, and at least one surface of the base material layer is a nonwoven fabric on which needle punch processing and / or hydroentanglement processing is performed. Preferably there is. As far as the inventors of the present application are aware, nonwoven fabrics that have been subjected to needle punching and hydroentanglement have many fuzz and low surface smoothness, so they have not been used in adsorbent sheets used for filters and the like. However, the present inventors have found a unique effect that the adhesive used as the entire sheet can be drastically reduced, particularly when used for a sheet containing an adsorbent and a thermoplastic resin between the base material layers. That is, in the conventional base material sheet, processing such as using an adhesive sheet to increase the adhesive strength to withstand practical use or increasing the heat press load on the entire adsorbent sheet has been performed. Adverse effects such as resistance and reduced deodorization performance were caused. On the other hand, the nonwoven fabric subjected to the needle punch processing and / or hydroentanglement processing of the present invention generates fluff, but the fluff enters the adsorption layer and becomes an anchor, and adhesion in the adsorption layer used for fixing the adsorbent The agent also exhibits the function of adhering the adsorbing layer and the base material layer, and it is possible to dramatically reduce the adhesive used as the entire sheet, thereby obtaining an adsorbent sheet that is flexible and has low ventilation resistance.

  In addition, although the base nonwoven fabric used for the adsorptive sheet of this invention is made into the nonwoven fabric by the hydroentanglement method and the needle punch manufacturing method, you may implement after these processing is made into the nonwoven fabric by another method. For example, the entanglement method described above may be performed after a long-fiber nonwoven fabric is formed by heating or pressure bonding. Such a base nonwoven fabric has a large number of fiber ends, and the fiber ends penetrate deeply into the adsorbent layer, thereby strengthening the bonding between the adsorption layer and the base material layer.

  The base nonwoven fabric of the present invention preferably has a fiber diameter of 3 to 100 μm. This is because, within such a range, the role of holding the adsorbing layer and the base material layer can be sufficiently achieved while maintaining flexibility. More preferably, it is 5-80 micrometers, More preferably, it is 10-60 micrometers.

  The base nonwoven fabric of the present invention preferably has a fiber length of 20 to 200 mm. This is because within this range, an appropriate number of fiber ends are present while maintaining the strength of the substrate. More preferably, they are 30 mm-150 mm, More preferably, they are 40 mm-100 mm.

  The filling density of the base nonwoven fabric constituting the base layer of the present invention is preferably 0.15 g / cc or less. This is because, after spraying the mixed granular material of granular adsorbent and thermoplastic powder resin, which will be described later, on this base nonwoven fabric, it is better to lower the packing density of the base nonwoven fabric to some extent when trying to obtain an adsorptive sheet by hot pressing This is because low ventilation resistance can be realized, adhesion can be improved, and an integrated structure can be achieved. More preferably, it is 0.10 g / cc or less.

The base nonwoven fabric of the present invention preferably has a thickness of 0.1 mm to 1.0 mm. If it is 0.1 mm or less, there is a concern that the granular adsorbent may come off or fall off when considering the spot weight, and if it is 1.0 mm or more, the entire sheet is too thick. The resistance increases, and as a result, the pressure loss in the entire unit becomes too high, which causes a practical problem. The basis weight is preferably 5 to 100 g / m ² . If it is less than 5 g / m ² , the powdery adsorbent and the thermoplastic powder resin are more likely to come off, resulting in a practical problem. If it is 100 g / m ² or more, the sheet thickness is increased, so that the structural resistance in the case of a pleated unit is increased, which is a practical problem.

  The fiber material constituting the base nonwoven fabric of the present invention is not particularly specified, such as polyolefin, rayon, polyester, polyamide, polyurethane, acrylic, polyvinyl alcohol, polycarbonate, etc. Of course, it may be a mixed fiber. In addition, a charged non-woven fabric, so-called electret sheet, which can increase the effect of removing submicron particles such as tobacco smoke particles, carbon particles, and sea salt particles can also be used as a substrate. This is because by using the electret sheet as a base material, it is possible to prevent dust and the like from entering the adsorption layer and block pores in the adsorption layer, thereby extending the filter life.

  Further, it is preferable that the adhesion between the fibers does not include a binder component that is given by fusion of the fiber components themselves or generally by post-processing. These resin components not only impair the low ventilation resistance, but even if they are integrated by heat treatment with a granular adsorbent and a thermoplastic powder resin mixture, the adhesion between fibers becomes strong, resulting in granular adsorption. The adhesiveness between the agent layer and the base non-woven fabric tends to be apparently reduced, and delamination or the like is liable to occur, resulting in a quality problem. That is, when some external force is applied to the adsorbent sheet by pleating or the like, if the fibers constituting the base material layer are firmly joined with an adhesive, the adhesive layer and the base material layer are broken at the joining point. On the other hand, if the base material layer is formed only by needle punching and / or hydroentanglement, the deformation slips between fibers in the base material layer during deformation to absorb the deformation. This is because destruction can be prevented. In order to avoid such a problem, even if a binder having a low melting point component or a low glass transition temperature is used, the adhesion force is improved, but at the same time, the surface coverage of the granular adsorbent is increased, so that the adsorption characteristics are reduced. Disadvantages arise. In any case, it is preferable that the adhesion between the fibers in the base material layer is not so strong.

  The base material layer used in the adsorbent sheet of the present invention is preferably made of a material having a melting point or decomposition temperature higher than the melting point of the thermoplastic resin constituting the adsorbing layer. This is because if the melting point or decomposition temperature of the material constituting the base material layer is higher than the melting point of the thermoplastic resin, the above-described problems are hardly caused when the adsorption layer is heat-bonded. Specifically, it is preferably 10 ° C. or higher and higher than the melting point of the thermoplastic resin, more preferably 20 ° C. or higher, and further preferably 30 ° C. or higher. The upper limit is not particularly problematic, but even if it exceeds 200 ° C., the effect is not changed, and the cost performance is generally lowered.

The fiber orientation of the substrate nonwoven fabric of the present invention may be random, cloth or parallel. Moreover, when performing a needle punch process, it is preferable that the number of penetrations is 5-120 pieces / cm < ² >. This is because, within this range, the bonding between the adsorption layer and the base material layer is strengthened while preventing the particulate adhesive from partially entering the base material layer and increasing the pressure loss. More preferably, it is 10-100 pieces / cm < ² >, More preferably, it is 15-80 pieces / cm < ² >.

The adhesive used in the present invention is preferably a thermoplastic powder resin. This is because the powder resin can be uniformly dispersed in the fluff portion of the adsorbent and the base nonwoven fabric.

  Examples of the thermoplastic powder resin include polyolefin-based, polyamide-based, polyurethane-based, polyester-based, ethylene-acrylic copolymer, polyacrylate, polyarene, polyacrylic, polydiene, ethylene-vinyl acetate, PVC, PS, and the like.

  The average size of the thermoplastic powder resin is preferably 1 to 40 μm. More preferably, it is 5-30 micrometers. More preferably, 95% by weight or more is contained in the range of 1 to 40 μm. If the particle size is within this range, the thermoplastic resin can reduce blocking of the surface pores of the granular adsorbent, while at the time of mixing with the adsorbent, the van der Waals force or electrostatic force to the granular adsorbent. This is because the preliminary adhesion is effectively performed and can be uniformly dispersed, and the partial peeling between the adsorbent layer and the base material layer can be effectively prevented.

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

  The melting point of the thermoplastic powder resin is preferably 80 ° C. or higher in consideration of the environmental temperature in the room of a moving vehicle or the like. More preferably, it is 100 ° C. or higher.

  The fluidity at the time of melting of the thermoplastic powder resin is preferably 1 to 80 g / 10 min in terms of the MI value described in JIS K 7210. More preferably, it is 3-30 g / 10min. Within such a range, the adsorption layer and the base material layer can be firmly bonded while preventing the surface of the adsorbent from being blocked.

  The amount of the thermoplastic powder resin used is preferably 1 to 40% by weight based on the particulate adsorbent. More preferably, it is 5 to 30% by weight. This is because, within such a range, an adsorption sheet excellent in adhesive strength with the base material layer, ventilation resistance, and deodorizing performance can be obtained.

  Examples of the method for adjusting the particle size of the thermoplastic powder resin include mechanical pulverization, freeze pulverization, and chemical adjustment. Moreover, although it can finally screen and obtain a fixed particle size, if it is a method which can ensure a fixed particle size, it will not specifically limit.

  As a structural unit, it is a mixed granular material of a base nonwoven fabric, a granular adsorbent and a thermoplastic powder resin, but in order to further improve the handleability, the exposed side of the granular adsorbent, that is, the facing surface of the base nonwoven fabric A base material layer having good air permeability (hereinafter referred to as an air permeable sheet) can be laminated. Since the breathable sheet has a thermoplastic powder resin adhering to the surface of the granular adsorbent, the thermoplastic powder resin can be effectively used and bonded. The breathable sheet can be the same as the base nonwoven fabric, but when using the adsorbent sheet as an air purification filter unit such as a pleated or wavy shape, the thinner the sheet thickness, the smaller the fold pitch. It is preferable to use a thin breathable sheet because it can be reduced, the adsorbent sheet area can be increased, the airflow resistance can be reduced, and the deodorizing performance can be improved. The overall thickness is preferably 0.3 to 2.5 mm.

  The average particle diameter of the adsorbent used in the adsorbent sheet of the present invention is an average of 60 to 800 μm in terms of JIS standard sieve (JIS Z8801) in consideration of air permeability, adsorbent dropout, sheet processability and the like. It is preferable that the thickness is 100 to 600 μm. When the average particle size is less than 60 μm, the airflow resistance becomes too large to obtain a certain high adsorption capacity, and at the same time, the sheet filling density tends to be high, which causes an early increase in airflow resistance when supplying dust. Also become. If the average particle diameter exceeds 800 μm, it will be easy to drop off, the initial adsorption performance in one pass will be extremely low, and it will be folded when it is used as a filter unit for air purification such as a pleated shape and a wave shape, and Workability at the time of corrugated processing deteriorates. In addition, said granular powder granular adsorbent can be obtained by carrying out predetermined particle size adjustment using a normal classifier.

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

  The amount of toluene adsorbed when measured in accordance with JIS K1474 of the granular adsorbent used in the adsorbent sheet of the present invention is preferably 20% by weight or more. This is because high adsorption performance is required for nonpolar gaseous and liquid substances such as malodorous gases.

The adsorbent used in the adsorbent sheet of the present invention may be used after chemical treatment for the purpose of improving the adsorption performance of polar substances and aldehydes.

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

  The adsorptive sheet of the present invention may be configured to include components having incidental functions such as antibacterial agents, antifungal agents, antiviral agents, and flame retardants. These components may be kneaded into fibers, non-woven fabrics, or woven fabrics, or may be attached and supported by post-processing. For example, by including a flame retardant, FMVSS. It is possible to manufacture an adsorbent sheet that meets the standards for retarding flame retardancy defined in 302 and UL flame retardant standards.

  The component having the incidental function may be attached or supported on the particulate adsorbent or the like. However, in this case, care must be taken not to impair the original adsorption function of the granular adsorbent. Moreover, it is possible to enhance the deodorizing function by adding a function having adsorption performance to fibers such as non-woven fabric and breathable sheet, for example, by attaching an acid or alkali chemical or using ion exchange fibers. is there.

  The basic manufacturing method of the adsorptive sheet will be described. First, the granular adsorbent and the thermoplastic powder resin are weighed to a predetermined weight, placed in a shaker (stirrer), and stirred at a rotational speed of 30 rpm for about 10 minutes. The moisture content at this time is preferably within 15% of the weight of the mixture. At this point, the thermoplastic powder resin is a mixture temporarily bonded to the surface of the granular adsorbent. Next, this mixed granular material is sprayed on a base nonwoven fabric, and a hot press process is implemented. The sheet surface temperature during hot pressing is preferably about 3 to 30 ° C, preferably 5 to 20 ° C higher than the melting point of the thermoplastic powder resin. Under the present circumstances, if an air permeable sheet is further laminated | stacked, the adsorptive sheet excellent in the handleability will be obtained.

  In addition, if pre-heated and pre-bonded with infrared rays or the like before heat treatment, mixed powder particles that tend to occur at the time of pressing will not be generated, and an adsorbent sheet with better dispersibility is produced. it can. The heat treatment using infrared rays does not cause an air current and the like, can be heated in a state where the mixed powder particles are allowed to stand, and scattering of the mixed powder particles can be prevented.

  In order to produce a sheet by finally hot pressing, a hot press method between rolls or a flat bed laminating method in which the upper and lower parts are sandwiched between flat heat belt conveyors can be used. The latter is more preferable for producing a more uniform thickness and adhesion. In addition, the combination of the base nonwoven fabric described in this patent and the characteristics of the above production method can suppress excessive binding between the particulate adsorbents, and at the same time has practically sufficient adhesive strength with the base nonwoven fabric. Can be obtained.

  Of course, a plurality of the structural units described above can be overlapped. Details of the formulation are given in the examples.

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

  The pleat peak apex distance of the filter unit of the present invention is preferably 2 to 30 mm. If it is 2 mm or less, the ridges are too close together and there is a lot of dead space, making it impossible to use the sheet efficiently. On the other hand, if it is 30 mm or more, the sheet development area becomes small, so that it is impossible to obtain a removal effect corresponding to the filter thickness.

In the filter unit of the present invention, any surface may be used on the upstream side, but it is preferable to use a bulky sheet surface upstream because the dust holding amount is increased.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the following examples are not intended to limit the present invention, and any design changes in accordance with the gist of the preceding and following descriptions are all within the technical scope of the present invention. Is included.

  In addition, the numerical value in an Example is the value measured by the following methods.

(1) Thickness Value when a pressure of 7 gf / cm ² is applied

(2) ASHRAE dust retention (measured under the conditions of a linear speed of 30 cm / s and a supply concentration of 0.5 g / m ³ )
Substitution characteristic of clogging degree against dust. When the initial ventilation resistance is increased by 150 Pa, the lifetime is determined, and the amount of dust deposited on the filter medium at that time is measured with a balance. The sample size was measured at 15 cm × 15 cm. In this example, the load test was conducted with the base sheet (powder adsorbent spraying side) upstream.

(3) Ventilation resistance is a value under a linear speed of 30 cm / s. Measurement was performed on a sample cut to 70φ.

(4) Deodorizing performance Using toluene gas, the upstream and downstream concentrations of the filter were measured with a gas-tech detector tube at a linear speed of 16 cm / s, and the value obtained by subtracting the downstream gas concentration from the upstream gas concentration was measured upstream. It was expressed as a percentage of the value divided by the gas concentration on the side. Measurement was carried out on a sample cut to 6cm x 6cm. In this patent, the upstream concentration was 80 ppm, and the removal rate data one minute after the start of measurement was described in the examples.

(5) Peel strength Measure the average peel strength of the substrate sheet and the granular adsorbent layer. The test piece is 50 mm wide and 200 mm long, with a tensile speed of 100 mm / min.

  Hereinafter, the embodiment will be described in detail.

Sheet A: Polypropylene fiber with a melting point of 163 ° C. of 2.2 dtex × 51 mm is carded to produce a web, and then formed into a sheet by the water punch method to produce a spunlace nonwoven fabric having a basis weight of 35 g / m ² , a thickness of 0.5 mm, and a ventilation resistance of 6 Pa. did. Thereafter, the sheet was charged by a corona charging method.

Sheet B: A web with a fineness of polypropylene fiber 5d having a melting point of 165 ° C. and a basis weight of 50 g / m ² is prepared by a spunbond method, and then a needle punch is applied to form a sheet having a thickness of 0.7 mm and a ventilation resistance of 4 Pa while entwining the fibers. Manufactured. Thereafter, the sheet was charged by a corona charging method.

Sheet C: A sheet in which a polypropylene fiber having a 2.2 dtex × 51 mm and a melting point of 163 ° C. and a polyester fiber having a melting point of 1.7 dtex × 44 mm and a melting point of 260 ° C. are mixed at a weight ratio of 1: 1. A charged nonwoven fabric having a basis weight of 25 g / m ² was produced.

Sheet D: A polypropylene film having a melting point of 163 ° C. was charged by corona charging. After splitting this film, it is applied to a card to produce a web, and further processed integrally with a spunbond nonwoven fabric made of polypropylene with a weight per unit of 15 g / m ² with a needle punch to produce a charged nonwoven fabric with a total basis weight of 40 g / m ² and a ventilation resistance of 4 Pa. did.

Sheet E: Polyester core / sheath fiber 4.4 dtex × 51 mm, 15% by weight (core melting point 265 ° C., sheath melting point 150 ° C.), polyester core / sheath fiber 22 dtex × 51 mm, 70% by weight (core melting point 265 ° C., sheath) (Melting point 190 ° C.) and non-core sheath fiber 17 dtex × 51 mm, 15% by weight (melting point 265 ° C.) fiber was mixed with a card and then made into a web, and then pressed to give a basis weight of 65 g / m ² and a thickness of 0.3 mm. A nonwoven fabric having a ventilation resistance of 4.0 Pa was prepared by a thermal bond method.

Sheet F: A non-woven fabric having a polyester long fiber nonwoven fabric of 2.2 dtex having a melting point of 265 ° C., a basis weight of 20 g / m ² , a thickness of 0.18 mm, and a ventilation resistance of 5 Pa was produced by a spunbond method (Toyobo Ecule 6201A).

Sheet G: sheet F an acrylic emulsion binder (glass transition point 0 ℃) 10g / m ² coated on basis weight 30 g / m ^2, to prepare a thickness 0.20 mm, airflow resistance 7Pa nonwoven.

( Reference Example 1 ) 1 kg of coal-based granular activated carbon having an average particle size of 300 μm and a toluene adsorption capacity measured by JIS K 1474 method of 47% by weight as a thermoplastic powder resin, flow beads EA209 (ethylene-acrylic acid) 0.1 kg by weight of copolymer, average particle size 10 μm, MI 9 g / 10 min, melting point 105 ° C.) was weighed and mixed for about 10 minutes. The mixed powder is spread on the sheet A so as to be 220 g / m ² , and the sheet E is overlapped from above and sandwiched between Teflon (registered trademark) / glass belts. It was set to 9 mm and a pressure of 10 N / cm ² , and hot pressing was performed at 120 ° C. for 30 seconds. Thereafter, it was cooled to obtain a desired adsorbent sheet.

( Reference Example 2 ) A granular activated carbon / thermoplastic powder resin mixture is prepared by the same material and method as in Reference Example 1 , and this mixed powder is spread on the sheet B so as to be 220 g / m ^2. E was overlapped from above and hot pressing and cooling were performed in the same manner as in Reference Example 1 to obtain a desired adsorbent sheet.

(Example 1 ) A granular activated carbon / thermoplastic powder resin mixture is prepared by the same material and method as in Reference Example 1 , and this mixed powder is spread on sheet C to 220 g / m ² , and further a sheet. E was overlapped from above and hot pressing and cooling were performed in the same manner as in Reference Example 1 to obtain a desired adsorbent sheet.

(Comparative Example 1) A granular activated carbon / thermoplastic powder resin mixture was prepared by the same material and method as in Example 1, and this mixed powder was dispersed on the sheet F so as to be 220 g / m ^2. E was superposed from above and hot pressing and cooling were performed in the same manner as in Example 1 to obtain a desired adsorbent sheet.

(Comparative Example 2) A granular activated carbon / thermoplastic powder resin mixture was prepared by the same material and method as in Example 1, and this mixed powder was dispersed on the sheet G so as to be 220 g / m ^2. E was superposed from above and hot pressing and cooling were performed in the same manner as in Example 1 to obtain a desired adsorbent sheet.
Table 1 summarizes the main data.

( Reference Example 3 ) A granular activated carbon / thermoplastic powder resin mixture is produced by the same material and method as in Reference Example 1 , and this mixed powder is spread on sheet D to 220 g / m ² , and further the sheet. E was overlapped from above and hot pressing and cooling were performed in the same manner as in Reference Example 1 to obtain a desired adsorbent sheet.

  As described above, the adsorptive sheet of the present invention has sufficient low pressure loss, high deodorization performance, and high dust holding capacity by selecting the particulate adsorbent, the thermoplastic powder resin, and the nonwoven fabric used for the base material. It can be realized while maintaining adhesiveness, and contributes greatly to the industry.

Schematic diagram of the adsorbent sheet of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Adsorbent sheet 2 Base material sheet 3 Granular adsorbent 4 Breathable sheet

Claims (4)

An adsorbent sheet comprising an adsorbent and a thermoplastic resin between base material layers, wherein at least one surface of the base material layer is a short fiber nonwoven fabric subjected to needle punching. The adsorption sheet according to claim 1 whose fiber length of the fiber used for said short fiber nonwoven fabric is 20-200 mm. Absorptive sheet of the short-fiber nonwoven fabric Ru nonwoven der contains no binder component according to claim 1 or 2 wherein. The adsorption sheet according to any one of claims 1 to 3 short-fiber nonwoven fabric Ru electret nonwoven der.