JP6585259B1 - Airlaid nonwoven fabric and production method thereof - Google Patents

Abstract

An air-laid nonwoven fabric having an uneven shape that improves filtration performance. An airlaid nonwoven fabric includes a plurality of valley surfaces (3) and raised surfaces (4) alternately provided adjacent to each other on one main surface (7a) of a sheet body (7), and valley surfaces (3 ) And a concave portion (1) that constitutes the seat body (7), and a convex portion (2) that has a raised surface (4) and that constitutes the seat body (7) integrally with the concave portion (1). The raised surface (4) includes an inclined surface (4a) formed between the center of the raised surface (4) and the valley surface (3), and short fibers constituting the sheet body (7) are inclined surfaces (4a). And protruding hair fibers (5) protruding outward. Thereby, filtration of an inclined surface is accelerated | stimulated and uniform filtration is implement | achieved in the whole uneven | corrugated shaped surface. [Selection] Figure 2

Description

  The present invention includes (1) sanitary products, disposable diapers, other absorbent articles, (2) interpersonal wipers, objective wipers, (3) drip absorbent sheets (fresh food rugs), and (4) highly breathable packaging materials. , Buffer material, (5) adsorbent sheet for gas adsorption, volatilizer used for fragrance, (6) filter, draining bag, tea pack, coffee filter, (7) lye removal sheet The present invention relates to an air-laid nonwoven fabric having the following: In particular, it relates to an airlaid nonwoven fabric for gas or liquid filters and a method for producing the same.

  An absorbent article that absorbs liquid discharged from the human body generally includes a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body between the top sheet and the back sheet. Absorbent articles are represented by disposable paper diapers and sanitary napkins, and can absorb and retain as much urine, menstrual blood, orimono as possible from human bodies as quickly as possible without side leakage, and are required to have thin and light performance.

  In order to satisfy this performance, it is indispensable to quickly improve the liquid conveyance and the diffusibility in the process in which the liquid discharged from the wearer passes through the top sheet and is absorbed and held in the absorbent layer. In a general absorbent article, the discharged material is repeatedly dropped or introduced into substantially the same part of the top sheet. For this reason, absorption concentrates on the fixed part of an absorption layer, and absorption is easy to be saturated. Moreover, since the dropped liquid has substantially the same aspect ratio, it saturates in the lateral direction before diffusing in the entire longitudinal direction. Even when only a part of the absorbent layer is used, it is easy to leak sideways from the top sheet. As a result, unless the absorbent layer is thickened and widened, the amount of absorption cannot be ensured.

  In order to avoid a certain concentration of absorption, Patent Document 1 proposes a liquid diffusion sheet having a plurality of linear (stripe) high-density regions by applying hot-pressure embossing to an airlaid nonwoven fabric composed of heat-bonding fibers and pulp. To do. The liquid diffusion sheet can improve rapid liquid permeation and diffusibility, and the vertical stripes prevent side leakage at the longitudinal edges. However, due to local densification, the sheet is hard and soft to the touch.

  In Patent Document 2, a pattern is imparted to a mat-forming wheel that forms a fiber web, and the formed web of web is cut to form a fiber web separator, which is used for an absorbent article such as a sanitary napkin. However, this fiber web has a very thin cutting site or a void, has a low strength and is difficult to handle.

  Patent Document 3 proposes a method of forming a fibrous web used for an absorbent article by an airlaid method or the like using a fluid-permeable woven fabric with a concavo-convex pattern. Although this fiber web is provided with a concavo-convex pattern on both sides, there is no description of quality characteristics and effects. And since the fiber web of patent document 3 has an unevenness | corrugation in both surfaces and an unevenness | corrugation exists also in the opposite surface on the side which contacts skin, the liquid transfer to an absorption layer is slow.

  In patent document 4, when manufacturing an airlaid nonwoven fabric, a projection of a synthetic resin is provided on a fiber collection net, and a short fiber is laminated thereon. An airlaid nonwoven fabric having the following is obtained. However, the convex part of the air laid nonwoven fabric does not have a top part, and inevitably has a flat convex part upper surface and a concave inclined surface. Since the flat convex upper surface has a relatively large area, a contact portion with the human skin is large and uncomfortable, and menstrual blood held on the nonwoven fabric sheet directly touches the human body. Patent Document 4 contemplates the possibility of using an absorbent material, a drip absorber, and a wiper, but there is no description of filter material applications such as oil mist removal.

  On the other hand, when manufacturing a nonwoven fabric sheet, the diameter, type, and fiber length of short fibers can be freely selected according to the application, and a nonwoven fabric sheet having a specific sheet thickness, density, and porosity can be manufactured. Nonwoven fabric sheets are used as filter materials because they are excellent in flexibility and processability, do not denature, are inexpensive, lightweight, have good transport efficiency, are non-toxic and highly safe. For example, as a gas filter, for air purifiers that trap airborne substances and clean indoor air, filters for air conditioners, filters for air conditioning equipment that removes fine dust in aseptic spaces such as clean rooms, dust masks Filter, dust collecting or vacuum cleaner filter for trapping dust, household kitchen, kitchen, filter for ventilation fan that captures oil mist that is atomized and flies in the air.

  Patent Document 5 is a nonwoven fabric of a multilayer fiber structure, the surface is embossed by thermocompression bonding to form a recess, the upper opening is larger than the bottom, and the angle between the tangent line that contacts the side surface of the recess and the bottom is A filter media that is 140-170 ° is disclosed. The concave portion is formed by thermocompression bonding of a spunbonded nonwoven fabric with an embossing roll provided with a large number of frustoconical convex portions. Has an inclined surface.

  The partial cross-sectional shape of the filter medium 60 of Patent Document 5 is shown in FIG. The filter medium 60 includes a concave portion 51 having a large number of concave surfaces 53 on one main surface and a convex portion 52 having a large number of convex surfaces 54 adjacent to the concave surface 53, and the convex surface 54 has an inclined surface 54a. However, the filter medium 60 formed by thermocompression bonding has a high fiber density as a whole, and in particular, the fiber density of the recesses 51 is extremely higher than the protrusions 52 due to embossing. Moreover, the temperature of the surface of the filter medium directly hit by the heating roll is higher than that inside, the melting rate of the surface fibers is large, and the clogging rate of the surface gap is high. For this reason, as shown in FIG. 15, the trapped material 59 easily accumulates on the surface through which the fluid is flowed, and the pressure loss rises early.

  Further, the filter medium 60 has a smooth compressed surface and no fiber protrusion or fuzz, so that the fluid flows 58a without resistance on the inclined surface 54a, and the amount of filtration on the concave surface 53 is larger than the amount of filtration on the inclined surface 54a. As shown in FIG. 15, a large amount of collected material 59 accumulates at the bottom of the concave surface 53 as shown in FIG. In addition, floating substances such as dust, dust, and hair in the fluid to be processed are not easily caught. Furthermore, the compression-formed filter medium 60 contains high-density fibers, so it is difficult to manually cut to a size suitable for the application. A ruler is applied to the filter medium 60 and cutting with a scissors, a cutter, or the like is required. .

  Moreover, a nonwoven fabric sheet is used also for liquid filters, such as filtration apparatuses, such as a drink, liquid food, a seasoning, purified water, sewage, and industrial waste water, a household water purifier, and a tea pack, for example. Patent Document 6 shows an embossed nonwoven coffee drip filter. By using an embossing roll having irregularities on the surface, the embossed portions are formed in a substantially uniform manner throughout the nonwoven fabric, thereby imparting strength to the nonwoven fabric. However, since the filter surface is compressed by embossing as in the cited document 5, clogging is likely to occur and the pressure rises early. In particular, a large amount of collected matter is accumulated on the bottom surface of the recess having a planar shape.

  An airlaid nonwoven fabric is known as a nonwoven fabric having a high surface porosity without being subjected to pressure embossing. In the airlaid nonwoven fabric, heat-adhesive fibers are laminated on a wire by gravity or suction force, and heated to form a sheet. Patent Document 7 shows an air filter in which an airlaid nonwoven fabric layer is disposed on one side of a base nonwoven fabric in which a plurality of holes are provided on the entire plane. However, in Patent Document 7, the filtration area is small because the filtration surface has no irregularities and is flat. In addition, when the filter is ignited, if there is no unevenness, the fire spread rate is fast, and the fire spread cannot be stopped or delayed due to the structure, which is not preferable for use in a ventilation fan such as a kitchen.

  Patent Document 8 discloses a patterned airlaid nonwoven fiber web comprising a plurality of non-hollow protrusions extending from the main surface of the nonwoven fiber web and a plurality of substantially flat land regions formed between adjacent protrusions. Indicates. That is, the air-laid nonwoven fabric web 70 shown in the cross-sectional shape of FIG. 16 has a three-dimensional shape including a convex portion 62 as a protruding portion and a concave portion 61 as a land region. However, when the fluid is allowed to flow in the direction of arrow 68 in a direction substantially perpendicular to the sheet surface of the air laid nonwoven fiber web 70, the fluid is introduced into the web 70 from the concave surface 63 at the entrance of the concave portion 61 where the thickness of the nonwoven fabric fiber is small and resistance is low. On the vertical surface 64a provided substantially parallel to the flow 68a, the amount of filtration is extremely small. In this structure in which almost no filtration is performed from the vertical surface 64a, efficient filtration using the entire surface cannot be performed efficiently, and filtration using the entire volume of the web 70 cannot be performed, and the advantage of the three-dimensional shape is not utilized. That is, the vertical surface 64a and the inside thereof hardly function as a filtration channel. Further, the filtration concentrates on the concave surface (bottom surface) 63 and local clogging occurs due to the collected matter 69. Further, as shown in FIG. 16, the collected matter 69 passes through the concave portion 61 having a thin filtration thickness from the concave surface 63. There is a risk of spilling 69a from the web 70. Further, in the web 70 of FIG. 16, the flow 68 cannot be uniformly dispersed or distributed on the convex surface 64 having a large area and a flat shape, and in this structure having no top, the collected matter is concentrated on the convex surface 64. There is also a risk of lamination.

  In addition, even when the non-woven fabric of Patent Document 4 having no top part and having a flat convex upper surface is used for the filter material, the fluid cannot be uniformly distributed throughout the entire surface. It is considered that the amount of fluid introduced into the inside is significantly reduced after the deposit is concentrated on the upper surface of the convex part. Usually, when the collected matter is accumulated on the filter surface and clogged, the filter is replaced. However, there is no conventional technique for removing the collected material from the surface and reusing it without replacement. Further, in a filter having irregularities, since the filtration volume of the convex portion is large and the resistance is large compared to the thin concave portion, a filter that makes the filtration volume as uniform as possible is desired. Furthermore, when a material to be treated contains a wide variety of shapes, sizes, masses, and properties, it cannot be treated with a single layer nonwoven fabric filter.

JP 2003-235894 A JP 2003-38567 A JP 2002-30561 A Japanese Patent No. 5024833 JP 2011-88349 A JP 2017-225589 A JP 2014-121893 A JP 2013-538297 A

  An object of this invention is to provide the airlaid nonwoven fabric which has the uneven | corrugated solid shape which improves filtration performance, and its manufacturing method. Moreover, it aims at providing the airlaid nonwoven fabric which can improve the shape of a convex part and the surface state of a convex surface, and can maintain the outstanding filtration performance, and its manufacturing method. An object of the present invention is to provide an airlaid nonwoven fabric for gas or liquid that can prevent clogging by collected matter and can perform uniform treatment over the entire filtration surface and the entire volume of the filter medium and maintain the filtration amount for a long period of time, and a method for producing the same. To do. An object of the present invention is to provide an airlaid nonwoven fabric that stops or delays the spread of fire due to ignition and a method for producing the same. An object of the present invention is to provide an airlaid nonwoven fabric capable of effectively removing oil mist and a method for producing the airlaid nonwoven fabric. An object of the present invention is to provide an airlaid nonwoven fabric capable of treating a fluid to be treated containing a wide variety of substances and a method for producing the same.

  The present invention is an air laid nonwoven fabric having irregularities, where the contact area of the individual protrusions to the human body is small, has high liquid permeability, enables more efficient treatment of the drained liquid from the human body, and It has a three-dimensional pattern used for sanitary products, sanitary napkins, disposable diapers and other absorbent articles, which improves the comfort to the skin by improving the reversal of drainage and reducing the contact area to the skin An object of the present invention is to provide an airlaid nonwoven fabric and a method for producing the same. Interpersonal wipers, objective wipers, drip-absorbing sheets, highly permeable packaging materials, cushioning materials, adsorbent sheets, fragrances, etc., air filters, draining bags, tea packs, coffee filters, lye removal sheets It is an object of the present invention to provide an airlaid nonwoven fabric having a three-dimensional pattern and a method for producing the same.

  The air-laid nonwoven fabric of the present invention is a sheet body (7) containing short fibers formed from heat-adhesive fibers, and a large number of alternately provided adjacent to each other on one main surface (7a) of the sheet body (7). The valley surface (3) and the raised surface (4), the concave portion (1) having the valley surface (3) and constituting the seat body (7), and the raised surface (4) and the concave portion (1). And a convex portion (2) constituting the sheet body (7), and the fiber density ratio of the concave portion (1) to the convex portion (2) is 1: 0.8 to 1.2. The raised surface (4) includes an inclined surface (4a) formed between the center of the raised surface (4) and the valley surface (3), and short fibers constituting the sheet body (7) are inclined surfaces (4a). And the protruding surface (4a) has a linear cross section or a convex arc shape, and the approximate center of each raised surface (4) is the seat body (7 ) With the highest top (4b) in the vertical direction from one main surface (7a), the top (4b) of each raised surface (4) is a cusp-shaped or curved top, and the cusp-shaped top ( 4b) has apexes on which the inclined surface (4a) is concentrated, and the top (4b) of the curved surface has a smaller surface area than the inclined surface (4a).

  Compared to a smooth conventional nonwoven fabric sheet having no inclined hairs, the air-laid nonwoven fabric of the present invention has an inclined surface (tapered surface) (4a) to a protruding fiber (5). Protruding irregularly, when the fluid (8) flows along the inclined surface (4a), the fluffy fiber (5) fluffing on the inclined surface (4a) becomes a resistor, and the fluid (8) flows. Partially disturbed. Thereby, a part (8a) of the fluid (8) enters the inside of the sheet body (7) from the inclined surface (4a) along the protruding fibers (5). At the same time, the fluid (8) is filtered by the inclined surfaces (4a) and the short fibers inside the sheet body (7), and the solid component in the fluid (8) can be captured. The remaining portion (8b) of the fluid (8) that does not enter the sheet body (7) further flows along the inclined surface (4a) and partially collides with the protruding fiber (5) of the inclined surface (4a). From the inclined surface (4a), the sheet body (7) enters and is filtered, and the remainder of the fluid (8) continues to flow along the inclined surface (4a) at a reduced flow rate. By repeating the flow along the inclined surface (4a), the remaining part of the fluid (8) reaches the valley surface (3) with a reduced flow rate. Thus, in the present invention, unlike the conventional case, there is no vertical surface where the filtration flow rate of the fluid (8) is remarkably small, and the fluid (8) easily enters the seat body (7) from the inclined surface (4b). The entire inclined surface (4a) of the raised surface (4) can be used for filtration. For this reason, clogging in which clogs concentrate only on the valley surface (3) due to partial filtration at the bottom of the valley surface (3) or valley surface (3) is prevented, and the filtration flow rate is maintained, Stable filtration performance can be exhibited for a long time. The slanted surface (4a) is not compressed, and the hairs, threads, dust, dust, cotton, fibers, etc. in the fluid (8) are easily collected and captured by the fluffy fibers (5) on the fuzzy surface. The fiber density ratio between the concave portion (1) and the convex portion (2) is 1: 0.8 to 1.2 and is substantially equal. Due to the uncompressed recess (1), the porosity of the recess (1) and the protrusion (2) is substantially equal, and the flow is concentrated on the recess (1) with a small filtration volume and the valley surface (3) at the inlet. Therefore, the fluid (8) can flow uniformly throughout the sheet body (7) without clogging. In addition, when using an airlaid nonwoven fabric that is bent into a pleated shape, an additional separating material is not interposed between the opposing surfaces of the opposing nonwoven fabric, and the valley surface (3) and the raised surface of one main surface (7a) (4) has the effect of preventing adhesion between the nonwoven fabrics.

  In the embodiment of the airlaid nonwoven fabric of the present invention, the inclined surface (4a) forms a filtration surface by a plurality of protruding fibers (5) and gaps (15) between the plurality of protruding fibers (5), and the protruding There are more hair fibers (5) than the first hair fibers (5a) and the first hair fibers (5a) which are inclined toward the valley surface (3) with respect to the perpendicular (V) of the inclined surface (4a). And a second protruding fiber (5b) inclined toward the center side of the raised surface (4) with respect to the perpendicular (V) of the inclined surface (4a). The second bristle fiber (5b) constitutes a resistor of the fluid (8) that flows on the inclined surface (4a), and guides the fluid (8) from the gap (15) into the seat body (7).

  At the time of manufacturing the air laid nonwoven fabric, suction force is applied from the other main surface (7b) side of the sheet body (7) to the one main surface (7a) side. The ratio of the heat-bonding fibers that fluff in the direction of the main surface (7a) is large. For this reason, the number of the second bristle fibers (5b) projecting in the center direction of the raised surface (4) is the same as that of the first bristle fibers (5a) projecting from the inclined surface (4a) in the valley surface (3) direction. )is more than. As an alternative, it is also possible to design both with an equal number or a smaller number of second fluff fibers (5b). For this reason, the fluid (8) flowing on the inclined surface (4a) from the center of the raised surface (4) collides with the second protruding fiber (5b) and flows by the second protruding fiber (5b). It is partially blocked and guided from the gap (15) into the sheet body (7) along the second protruding fiber (5b). In this case, since there are a large number of second bristle fibers (5b) functioning as resistors on the inclined surface (4a), filtration on the inclined surface (4a) is promoted. On the other hand, the first bristle fiber (5a) is inclined and raised in the downstream direction of the flow, so that the fluid (8) colliding with the first bristle fiber (5a) becomes the first bristle fiber (5a). Most of the fluid does not enter the gap (15) and continues to flow along the inclined surface (4a).

  In the air-laid nonwoven fabric of the present invention, the vertical cross-sectional shape of the inclined surface (4a) is linear or convex arc shape.

The vertical cross-sectional shape of the inclined surface (4b) is a linear or convex arc shape (arc) between the center of the raised surface (4) and the valley surface (3). The filtration of the fluid (8) that progresses uniformly and gradually on the inclined surface (4b), and it is difficult for the collected matter to concentrate and accumulate on a part of the inclined surface (4b).
On the other hand, when the inclined surface is formed in a concave arc shape, the filtration concentrates and the collected matter concentrates and accumulates near the bottom surface of the concave arc shape, and the filtration rate is remarkably reduced near the vertical plane substantially parallel to the fluid flow direction. To do. For this reason, if the inclined surface is a concave arc, the filtration performance cannot be fully exhibited.

  The air-laid nonwoven fabric of the present invention has a top (4b) that is the highest in the vertical direction from one main surface (7a) of the sheet body (7) at the approximate center of each raised surface (4), and the top (4b) The apex of the apex or curved surface, the apex of the apex (4b) has an apex on which the inclined surface (4a) is concentrated, and the apex of the curved shape (4b) has a smaller surface area than the inclined surface (4a). Have

  The flow (8) is separated substantially uniformly by the top (4b) provided at the approximate center of the raised surface (4), and the filtration surface is formed by the non-vertical inclined surface (4a). On the other hand, in the prior art shown in FIG. 16, the vertical surface 64a is not a filtration surface but a dead area. Further, the uniform separation of the fluid (8) enables volume filtration of the entire sheet body (7) inside the inclined surface (4a). Furthermore, since the surface of the top part of the curved surface shape and the planar shape is smaller than that of the inclined surface (4a), a large amount of collected matter is not accumulated only on the top part (4b). On the other hand, in the conventional technique (FIG. 16) in which the area of the upper surface (top) 64 having a planar shape is larger than that of the valley surface, a large amount of collected matter is accumulated on the upper surface 64 of the protrusion.

  In the embodiment of the airlaid nonwoven fabric of the present invention, when the straight path (9) is provided with a number of valley faces (3) connected to one main surface (7a) of the sheet body (7), the straight path (9) is The fiber density of the recess (1) which has an open end (9a) at least at one end and constitutes the straight path (9) is 0.02 to 0.2.

  Since the straight path (9) in which a large number of valley surfaces (3) are connected is formed, the nonwoven fabric is easy to cut. That is, in the present invention, due to the integral synergistic effect of the thin straight path (9) functioning as the cut portion and the plurality of convex portions (1) that guide the cut and run along the straight path (9), Releasing the air-laid nonwoven fabric (10) back and forth along the straight path (9) from the open end (9a), for example, by hand, depending on the application and dimensions, without using a separate perforation Can be cut smoothly into a desired dimension.

  It is preferable when used as a home exhaust fan filter. Also, when the collected matter is deposited on the valley surface (3), the collected material accumulated on the valley surface (3) along the straight path (9), by water flow or using a scraper Objects can be scraped and washed, and can be easily removed from the open end (9a) of the straight path (9). For this reason, the air laid nonwoven fabric can be used for a long time and can be reused.

  If the fiber density of the recess (1) is less than 0.02, the tear strength and tensile strength are weak, and there is a risk of tearing before use. Moreover, the filtration volume is too small, and there is a possibility that the collected matter comes off. When the fiber density exceeds 0.2, it is difficult to cut manually. In addition, since the conventional thermal bond (air-through) nonwoven fabric (Comparative Example 1c) to be described later has long and longitudinally oriented fibers, it is not easy to cut by hand other than the longitudinal direction regardless of the fiber density.

  In the embodiment of the air-laid nonwoven fabric of the present invention, the sheet body (7) contains 30 to 100% by weight of short fibers formed from heat-adhesive fibers having a single yarn fineness of 0.2 to 60 dtex and a fiber length of 2 to 15 mm. Single layer.

  In the embodiment of the air-laid nonwoven fabric of the present invention, the sheet body (7) includes a part or all of the raised surface (4) and forms one main surface (7a) of the sheet body (7). A first layer (11) and a second layer (12) laminated on the joining surface (11a) of the first layer (11) opposite to one main surface (7a) of the sheet body (7) And at least. Either one of the first layer (11) and the second layer (12) is made of 30 to 100 short fibers formed from heat-adhesive fibers having a single yarn fineness of 1.5 to 60 dtex and a fiber length of 2 to 15 mm. Includes weight percent. Either one of the first layer (11) and the second layer (12) is composed of 30 to 100 short fibers formed from heat-adhesive fibers having a single yarn fineness of 0.2 to 60 dtex and a fiber length of 2 to 15 mm. Includes weight percent.

The method for producing an airlaid nonwoven fabric according to the present invention comprises a step of dispersing defibrated thermal adhesive fibers in an air stream and releasing them from an ejection device, and the released thermal adhesive fibers having air permeability and a large number of nets. A step of depositing a single layer or two or more layers of the fiber collection net (27) having the concave portion (22) and the net convex portion (21) while applying a suction force, and the deposited heat-adhesive fiber is heated and melted. And forming a sheet body (7) containing short fibers heat-sealed with each other. The sheet body (7) includes a concave portion (1) and a convex portion (2) having shapes corresponding to the net convex portion (21) and the net concave portion (22), respectively, and the concave portion (1) and the convex portion (2). The fiber density ratio is 1: 0.8 to 1.2, and the raised surface (4) of the convex portion (2) is an inclination formed between the center of the raised surface (4) and the valley surface (3). The surface (4a) and the short fibers constituting the sheet body (7) have protruding hair fibers (5) protruding outward from the inclined surface (4a), and the vertical cross-sectional shape of the inclined surface (4a) is a straight line Each of the raised surfaces (4) is provided with an apex (4b) that is the highest in the vertical direction from one main surface (7a) of the seat body (7), and each raised surface (4). The apex (4b) is a apex of a pointed shape or a curved shape, the apex (4b) of the apex shape has an apex on which the inclined surface (4a) is concentrated, and the apex (4b) of the curved shape is an inclined surface (4a) has a smaller surface area.

  Since the surface is formed by the airlaid method without applying pressure, the fiber density of the concave portion (1) and the convex portion (2) is substantially constant, the surface is hardly clogged, and uniform filtration is performed over the entire volume of the nonwoven fabric. it can.

  In the embodiment of the method for producing an air laid nonwoven fabric of the present invention, the step of depositing the heat-adhesive fiber while applying a suction force causes a stronger suction force to be applied to the net recess (22) compared to the net protrusion (21). Process, first raised fiber (5a) inclined to the trough (3) side with respect to the perpendicular (V) of the inclined surface (4a), and raised surface (4) with respect to the perpendicular (V) of the inclined surface (4a) ) Forming a second protruding fiber (5b) inclined toward the center side. The step of applying a strong suction force to the net recess (22) includes the step of forming the second protruding hair fibers (5b) on the inclined surface (4a) more than the first protruding hair fibers (5a).

  Since a strong suction force is applied to the net recess (22), the inclined surface (4a) and the top (4b) of the airlaid nonwoven fabric corresponding to the net recess (22) are more prominent than the valley surface (3) of the recess (1). Many hair fibers (5) are fluffy.

  Since a suction force that flows from the main surface (27a) side of the fiber collection net (27) to the other surface (27b) side is applied, a raised surface (4) with respect to the perpendicular (V) of the inclined surface (4a) is deposited. ) There are a large number of second bristle fibers (5b) that incline and protrude toward the center side as compared with the first bristle fibers (5a) that incline toward the valley surface (3). Filtration on the inclined surface (4a) and three-dimensional filtration inside the convex portion (2) are promoted by the second bristle fiber (5b) acting on the fluid with high resistance.

  The air-laid nonwoven fabric of the present invention has irregularities on the surface, and the fibers protrude from the inclined surface of the convex portion. Therefore, the filtration of the inclined surface is promoted, and uniform filtration is realized over the entire uneven surface. Further, in the present invention, since the surface is not compressed, trapped substances do not concentrate on the surface, and the entire volume of the nonwoven fabric can be used for three-dimensional filtration. Therefore, high-performance filtration can be realized without requiring long-term replacement.

  Since there are a large number of convex surfaces on one side, the contact area with the skin is small, so the stimulation to the skin is small, the wet feeling due to the liquid discharged from the human body is small, and the stuffiness is small. Moreover, since there are many minute spaces between the skin and the nonwoven fabric, the feeling of high humidity and stuffiness brought about by the discharged liquid is improved and the comfort is high. On the other hand, since the surface on the side opposite to the surface having the convex portion is flat, the transfer of the liquid to the absorption layer is smooth.

  Further, when applied to various interpersonal wipers and objective wipers, the scraping property of dust and dirt is improved by the unevenness, and when applied to the drip absorbing sheet, the wetback is reduced and the freshness maintaining effect is enhanced. Moreover, if it applies to an adsorbent sheet, since the surface area is large, the gas adsorption effect is enhanced. Furthermore, if it is applied to an lye removal sheet, the effect of capturing lye is enhanced due to the large surface area. In addition, it is also effective for volatile substances such as fragrances, various air-permeable packaging materials, cushioning materials, air filters, draining bags, tea packs, and coffee filters.

The top view which shows the air laid nonwoven fabric by embodiment of this invention Sectional drawing which shows the airlaid nonwoven fabric by embodiment of this invention The expanded sectional view which shows the inclined surface of the air laid nonwoven fabric of this invention Enlarged sectional view showing the inclined surface of airlaid nonwoven fabric Sectional drawing which shows the shape of the inclined surface of the airlaid nonwoven fabric of this invention The enlarged photograph which shows the shape of the inclined surface of the air laid nonwoven fabric of this invention The expanded sectional view which shows the shape of the vertex of the air laid nonwoven fabric of this invention FIG. 2 is a plan view showing an airlaid nonwoven fabric according to various embodiments of the present invention. Sectional drawing which shows the air laid nonwoven fabric (multilayer structure) by other embodiment of this invention Sectional drawing which shows the air laid nonwoven fabric by the modification of this invention Schematic cross-sectional view showing a state where fluid flows in the air laid nonwoven fabric of the present invention Sectional drawing which shows the fiber collection net which manufactures the airlaid nonwoven fabric of this invention Cross-sectional view showing a state where an airlaid nonwoven fabric is deposited on a fiber collection net Schematic sectional view showing a conventional nonwoven fabric filter Schematic cross-sectional view showing the state of fluid flowing through a conventional nonwoven fabric filter Schematic cross-sectional view showing the state of fluid flow in a conventional airlaid nonwoven fabric

  Embodiments of an airlaid nonwoven fabric and a method for producing the same according to the present invention will be described below with reference to FIGS.

  The air-laid nonwoven fabric (10) according to the present invention shown in FIGS. 1 and 2 includes a sheet body (7) including short fibers formed from heat-adhesive fibers, and one main surface (7a) of the sheet body (7). A plurality of valley surfaces (concave surfaces) (3) and raised surfaces (convex surfaces) (4) provided alternately and adjacent to each other, and a recess (1) having a valley surface (3) and constituting the sheet body (7) And a convex part (2) having a raised surface (4) and constituting the sheet body (7) integrally with the concave part (1).

  Thermal adhesive fibers are heat-melted and bonded to each other. The nonwoven fabric itself is fixed in a network structure by interfiber bonding by melting, for example, polyolefins, polyolefins grafted with unsaturated carboxylic acids, polyesters , Polyvinyl alcohol and the like. A core-sheath type or eccentric side-by-side type composite fiber is suitable as the polyolefin-based heat-bonding fiber. Examples of the polyolefin constituting the sheath or the fiber outer peripheral portion include polyethylene and polypropylene. As the polymer constituting the core component or the fiber inner layer portion, a polymer having a melting point higher than that of the sheath and not changing at the heat bonding treatment temperature is preferable. The combination of the composite fibers is, for example, polyethylene / polypropylene, polyethylene / polyester, polypropylene / polyester, etc., but may be modified as long as the effects of the present invention are not impaired. Furthermore, a fibrillar fiber may be used. For example, it is SWP of Mitsui Chemicals.

  The fiber density ratio of the concave portion (1) and the convex portion (2) constituting the sheet body (7) of the air laid nonwoven fabric (10) is 1: 0.8 to 1.2. Since the present invention is a nonwoven fabric formed by the airlaid method, the concave portion (1) is not particularly compressed, and both values are substantially equal. The fiber density ratio is preferably 1: 0.82 to 1.17. A boundary between the concave portion (1) and the convex portion (2) is shown by a broken line in FIG. The boundary can be measured by the diameter, major axis, or diagonal dimension of the net recess (22) of the fiber collection net (27) for manufacturing the airlaid nonwoven fabric described later.

  As shown in FIG. 2, the raised surface (4) of the convex portion (2) includes an inclined surface (4a) formed between the center of the raised surface (4) and the valley surface (3), and the seat body (7). The short fibers constituting the surface have protruding hairs (5) that protrude outward from the inclined surface (4a) and fluff. Since the surface area of the raised surface (4) is larger than that of the valley surface (3), a large amount of filtration proceeds on the inclined surface (4a) which is the surface of the raised surface (4). In the conceptual cross-sectional view of the air-laid nonwoven fabric (10) in FIG. 2, the fuzzy fibers (5) are described in a straight line for the sake of simplicity, but actually, curved fuzzy fibers (5) are also included. The same applies to the other drawings.

  As shown in FIGS. 3 and 4, the inclined surface (4a) of the raised surface (4) constitutes a filtration surface by a plurality of hair fibers (5) and gaps (15) between the plurality of hair fibers (5). To do. The number of protruding fibers (5) is greater than the number of first protruding fibers (5a) and the first protruding fibers (5a) inclined to the valley surface (3) with respect to the perpendicular (V) of the inclined surface (4a). A second protruding fiber (5b) which exists and is inclined to the center side of the raised surface (4) with respect to the perpendicular (V) of the inclined surface (4a). The second bristle fiber (5b) constitutes a resistor of the fluid (8) flowing through the inclined surface (4a), and guides the fluid (8) from the gap (15) to the inside of the sheet body (7) (8a ). In the inclined surface (4a) of the air laid nonwoven fabric (10) of the present invention having a large number of second fluff fibers (5b) shown in FIG. 3, a large amount of fluid (8) is guided into the seat body (7) (8a). Therefore, three-dimensional filtration including the entire sheet body (7) can be realized. On the other hand, in the inclined surface (4a ′) containing a large amount of the first protruding fibers (5a) shown in FIG. 4 different from the present invention, the amount of the fluid (8) introduced into the seat body (7) is small (8a ), Because of the large amount of fluid that continues to flow on the inclined surface (4a) (8b), the filtration concentrates on the valley surface (3).

  The vertical cross-sectional shape of the inclined surface (4a) can be formed in a linear shape shown in FIG. 5 (a) or a convex arc shape shown in FIG. 5 (b). In FIG. 5, the description of the protruding fiber (5) is omitted to clearly show the shape. 6 (a) and 6 (b) are enlarged photographs corresponding to the left side of the inclined surface (4a) in FIGS. 5 (a) and 5 (b), respectively. 6 (a) and 6 (b), linear and convex arc-shaped inclined surfaces (4a) and protruding hair fibers (5) protruding from the inclined surfaces (4a) can be confirmed. FIG. 7 shows an embodiment of the top portion (4b) provided at the approximate center of each raised surface (4) of each convex portion (2), and FIGS. 6 (a), (b) and (c) are respectively shown in FIG. The apex of the pointed shape, curved surface shape, and planar shape is shown. The top portion (4b) is provided at the highest position in the vertical direction from one main surface (7a) of the seat body (7).

  The three-dimensional shape of each convex portion (2) is formed into a polygonal pyramid shape, a conical shape, a spherical shape, an elliptic spherical shape, or a trapezoid shape by the inclined surface (4a) and the top portion (4b) of the raised surface (4). The planar shape of each convex part (2) includes a circle (FIG. 8 (a)), an ellipse (FIG. 8 (b)), and a hexagon (FIG. 8 (c)) in addition to the rhombus illustrated in FIG. It is formed into a polygon. In the case of a circle, the diameter is a dimension, in the case of an ellipse, the dimension of a minor axis or a major axis, and in the case of a polygon, the dimension of a diagonal is 1 to 20 mm, preferably 2 to 15 mm. The height from the other main surface (7b) to the top (4b) of the sheet body (7) is 0.5 to 12 mm, preferably 1 to 10 mm. If the diameter (or short diameter or diameter) of the convex portion is less than 1 mm, the effect obtained by the convex portion is small, and if it exceeds 20 mm, the sheet strength is lowered and is not practical. If the height of the convex portion is less than 0.5 mm, the effect obtained by the convex portion is small, and if it exceeds 12 mm, for example, the thickness of the collection net (27) described later becomes too thick and the nonwoven fabric sheet is crushed or damaged. Etc. are likely to occur, resulting in production problems. The height to the top part (4b) can be easily changed by changing the size of the convex part (21) and the concave part (22) of the air-collecting net (27) described later, and changing the heat treatment conditions of the fiber web, for example. Can be adjusted.

  In the nonwoven fabric of the present invention, a zone where a large number of convex portions (2) are present may not exist on the entire surface of the sheet body (7). For example, a zone in which a large number of convex portions (2) are present and a zone that does not exist may coexist in alternating stripes such as vertical, horizontal, and diagonal, or a zone in which a large number of convex portions (2) are present. The pattern may be circular, square, or the like. Further, within the scope of the present invention, the convex portion (2) may not have a fixed shape, and may represent a character, a wave pattern, a stripe pattern, a lattice pattern, or some pattern or logo.

  The apex (4b) having a pointed shape shown in FIG. 7 (a) has an apex on which the inclined surface (4a) is concentrated. Both the curved top (4b) and the planar top (4b) have a smaller surface area than the inclined surface (4a). In the present invention, the surface area of the top surface (4b) of the curved surface and the planar shape is smaller than that of the inclined surface (4a). Unlike the conventional technique, a large amount of collected material is not accumulated only on the top (4b).

  The ratio of the surface area between the valley surface (3) and the raised surface (4) is 1: 1.5-10. Preferably it is 1: 2-8. If it is less than 1: 1.5, it is difficult to obtain the performance characteristics obtained by the convex portion (2). If it exceeds 1:10, the convex portion (2) is high and the nonwoven fabric sheet is likely to be crushed or damaged. Not right. In order to make the ratio of the surface areas within the above range, for example, the structure design of the collection net (27) described later may be optimized. For example, in the case of the convex portion (2), the surface area is a substantial three-dimensional surface area of the raised surface (4) of the convex portion (2), and is not a two-dimensional projected area. The surface area of the recess (1) is the same.

  In the nonwoven fabric sheet of the present invention, the projected area ratio of the valley surface (2) of the concave portion (1) and the raised surface (4) of the convex portion (2) is 1: 0.2 to 4.0, preferably 1: 0. .4 to 3.0. When the projected area ratio is smaller than 1: 0.2, the convex portion (2) is small and the effect of the present invention is hardly exhibited. When the ratio of the projected areas is greater than 1: 4.0, the convex portion (2) is large, so that the sheet strength of the concave portion (1) is lowered, which is not practical. In order to set the projected area ratio within this range, for example, the structure design of the collection net (27) described later may be optimized. The projected area is the ratio of the concave portion to the convex portion as a plane when the nonwoven fabric is viewed from above. That is, in FIG. 1, the projected area of the valley surface (3) of the recess (1) is the area around the rhombus, and the projected area of the raised surface (4) of the protrusion (2) is the area of the rhombus.

  As shown in FIGS. 1 and 8, the air-laid nonwoven fabric (10) can include a straight path (9) in which a number of valley surfaces (3) are connected to one main surface (7a) of the sheet body (7). The straight path (9) has an open end (9a) at least at one end. The fiber density of the recessed part (1) which comprises a straight path (9) is 0.02-0.2, Preferably it is 0.03-0.18. The sheet body (7) is a single layer containing 30 to 100% by weight of short fibers formed from heat-adhesive fibers having a single yarn fineness of 0.2 to 60 dtex and a fiber length of 2 to 15 mm.

  Although the thickness of the fiber can be selected depending on the application, the preferred fineness is 0.2 dtex to 60 dtex, more preferably 0.8 dtex to 35 dtex, but the appropriate range varies depending on the application. Here, if the single yarn fineness exceeds 60 dtex, the air-laid nonwoven fabric sheet obtained is hard and unsatisfactory, the skin is greatly stimulated, and is difficult to process manually. On the other hand, if it is less than 0.2 dtex, the productivity of the nonwoven fabric is lacking and it is not practical.

  When the heat-adhesive fiber is thin, the number of constituent fibers is large, so there are few dropped fibers, and when applied to an absorbent article, the texture and the touch are soft. If it is thick, the gap between the fibers is large and the nonwoven fabric is bulky, and the air permeability is improved, so that the humidity in the vicinity of the skin is suppressed and the feeling of stuffiness is reduced. In addition, when the short fiber to be used is applied to an interpersonal wiper and an objective wiper, the fineness can be set according to the object, and the interfacial wiper is 0.2 to 5 dtex. For the objective wiper, the fineness varies depending on the application, for example, 0.2 to 5 dtex for furniture and 10 to 60 dtex for sink. Examples of interpersonal wipers include disposable towels, cosmetic wet sheets, and cosmetic puffs. Examples of objective wipers include flooring wipers and hand wipers.

  The length of the heat-adhesive fiber is preferably 2 to 15 mm. If the fibers are short, the spreadability is improved, and a more uniform nonwoven fabric is likely to be obtained. However, if the fibers are less than 2 mm, the fibers are close to a powder, making it difficult to form a network structure by bonding between fibers, and the strength as a nonwoven fabric is reduced. It is not preferable because it lacks properties. On the other hand, if the length is longer than 15 mm, the strength of the nonwoven fabric increases, but the fibers tend to become entangled during the pneumatic transportation of the fibers during the production of the nonwoven fabric, and this is not preferable because it increases the fiber mass defects. In particular, in the airlaid method, the fiber length is short, and it is preferable that the thickness is 3 to 8 mm because the unevenness is sufficiently formed in the lamination to the air permeable sheet having the unevenness.

  The nonwoven fabric sheet of the present invention includes, in addition to the above heat-adhesive fibers, regenerated fibers such as rayon, semi-synthetic fibers such as acetate, synthetic fibers such as polyester, polypropylene, polyamide, and vinylon, fibrillar fibers such as SWP, Other fibers such as natural fibers such as pulp, cotton and hemp may be included. In this case, the ratio of the heat-adhesive fiber in the nonwoven fabric sheet is preferably 30 to 100% by weight, more preferably 70 to 100% by weight. When the amount is less than 30% by weight, there is a high possibility that the above-mentioned other fibers may fall off, and the wet strength may be lowered, which causes a practical problem. In addition, when the strength is required and it is not necessary to include other hydrophilic fibers, for example, the proportion of the heat-adhesive fibers in the nonwoven fabric sheet is preferably 100% by weight.

  As shown in FIG. 9 (a), the sheet body (7) includes a first layer (11) including part or all of the raised surface (4) and forming one main surface (7a) of the sheet body (7). And a second layer (12) laminated on the joining surface (11a) of the first layer (11) on the opposite side of the one main surface (7a) of the sheet body (7) An airlaid nonwoven fabric (20) having a structure may be formed. The first layer (11) contains 30 to 100% by weight of short fibers formed from heat-bondable fibers having a single yarn fineness of 1.5 to 60 dtex, preferably 1.7 to 35 dtex and a fiber length of 2 to 15 mm. The second layer (12) contains 30 to 100% by weight of short fibers formed from heat-bondable fibers having a single yarn fineness of 0.2 to 60 dtex, preferably 0.2 to 35 dtex and a fiber length of 2 to 15 mm. The first layer (11) and the second layer (12) may be formed in the opposite direction (that is, Example 11 with respect to Example 10 described later). In the airlaid nonwoven fabric (20) having a two-layer structure, the fiber density ratio between the concave portion (1) and the convex portion (2) is 1: 0.8 to 1.2, preferably 1: 0.88 to 1.19. The fiber density of the recess (1) is 0.02 to 0.2, preferably 0.03 to 0.11. As shown in FIG. 9B, an airlaid nonwoven fabric (30) may be formed in a three-layer structure by further stacking a third layer (13) on the second layer (12). It may be formed by laminating more than the layers.

  In the embodiment, the other main surface (7b) of the sheet main body (7) is a flat airlaid nonwoven fabric (10), but the other main surface (7b) of the sheet main body (7) is a convex portion ( A recessed portion (6a) (FIG. 10 (a)) or a protrusion (6b) (FIG. 10 (a)) may be provided on the opposite side of the raised surface (4) of 2). When the depression (6a) is formed on the other main surface (7b) on the back side of the raised surface (4), the thickness of the protrusion (2) that maximizes the filtration volume is reduced, thereby reducing the protrusion (2). The flow of the fluid is promoted, and filtration with a uniform flow velocity is realized in the entire convex portion (2) and concave portion (1). Further, when the depressed portion (6a) or the protruding portion (6b) is provided on the other main surface (7b) of the sheet body (7), when the air laid nonwoven fabric is folded and used in a pleated shape, it is caused by adhesion between the facing surfaces. The filtration function can be prevented from being stopped and the filtration performance can be maintained for a long time. In addition to a single layer, a depression (6a) or a protrusion (6b) may be formed on the other main surface of the sheet body (7) having a multilayer structure.

An embodiment of a method for producing an airlaid nonwoven fabric according to the present invention will be described below.
In the method for producing an air-laid nonwoven fabric having a three-dimensional pattern of the present invention, a fiber collection net having a large number of convex portions and concave portions and having air permeability is used. Alternatively, a fiber collecting net having a two-layer structure in which an air permeable sheet having a large number of recesses or openings is laminated on a metal or plastic net can be used. By depositing heat-adhesive fibers in the concave portions of the fiber collection net, a sheet-shaped airlaid nonwoven fabric having a three-dimensional pattern of irregularities is produced. The method of joining the net of the two-layered collection net and the air permeable sheet is possible by stitching, bonding with an adhesive, and heat sealing by heat, but reuse of the fiber collection net for bonding by adhesive and heat sealing. In addition, in the case of the adhesive, at least one of the net and the air permeable sheet is limited to a material having thermal adhesiveness, and therefore joining by sewing is desirable.

  In the present invention, a predetermined amount of defibrated heat-adhesive fiber having a single yarn fineness of 0.2 to 60 dtex and a fiber length of 2 to 15 mm and other fibers as necessary are uniformly dispersed in an air stream. Air is sucked from the lower part of the fiber collection net while being discharged from the fine holes of the ejection device and is deposited on the fiber collection net having a large number of recesses installed in the lower part or on the fiber collection net having a two-layer structure. If necessary, after repeating this operation a plurality of times, heat treatment is performed at a temperature 15 to 40 ° C. higher than the melting point of the adhesive component of the heat-adhesive fiber, and a sheet-like pattern having a three-dimensional pattern in which a large number of irregularities are formed. Airlaid nonwoven fabric is manufactured.

  In the manufacturing method of the nonwoven fabric by the thermal bond method, the spunlace method, and the chemical bond method, since the fiber with a long fiber length of 38-64 mm is generally used, formation of unevenness | corrugation is not enough. In the spunbond method and the melt blow method, since the fibers are continuously spun, the formation of irregularities is not sufficient. That is, in the lamination of nonwoven fabrics having a short fiber length and unevenness, an airlaid method that sufficiently forms unevenness is optimal.

  The air-laid nonwoven fabric of the present invention is composed of heat-adhesive fibers and other fibers as required. That is, in addition to 100% by weight of heat-adhesive fibers, one or more airlaid nonwoven fabrics comprising, for example, heat-adhesive fibers + pulp fibers, heat-adhesive fibers + polyester fibers, or heat-adhesive fibers + pulp fibers + chemical binders. May be. Since heat-adhesive fibers generally have low hydrophilicity, other fibers are preferably hydrophilic fibers, and include pulp fibers and rayon fibers. In particular, it is preferable that the surface having the concave portion is mainly composed of heat-adhesive fibers in view of the strength of the nonwoven fabric. When it is necessary to develop water absorption on the surface of the convex portion, hydrophilic non-thermal adhesive fibers such as pulp fibers can be mixed. However, the composition and fiber thickness can be appropriately set depending on the application. Here, “main component” means that the heat-adhesive fiber is 70% by weight or more, preferably 85% by weight or more, and may contain other fibers and pulp of 30% by weight or less.

The manufacturing method of the airlaid nonwoven fabric by this invention is demonstrated with FIG.12 and FIG.13.
While uniformly dispersing the air-bonded fiber of a predetermined amount in the air flow as a main component, it is discharged from the pores of a jetting device (not shown), and a large number of net convex portions (21) and net concave portions (22) are formed. It is dropped onto the fiber collection net (27) having a single layer structure or two or more layers, and the heat-adhesive fibers are sucked in the direction of the other surface (27b) (arrow 26) of the fiber collection net (27). Is deposited on the fiber collection net (27). If necessary, this operation is repeated a plurality of times to laminate the fiber web, whereby the airlaid nonwoven fabric (20, 30) having the two-layer or three-layer structure is obtained.

  When the heat-adhesive fiber is deposited on the fiber collection net (27) while applying the suction force (26) shown in FIG. 12, as shown in FIG. 3, the concave portion (1 ) Of the first protruded fibers (5a) inclined toward the valley surface (3) and the second protruded fibers (5b) inclined toward the center of the raised surface (4). At this time, since the suction force (26) flowing in the direction of the arrow in FIG. 12 is applied from the main surface (27a) side to the other surface (27b) side of the fiber collection net (27), the first protruding fiber ( A number of second fluff fibers (5b) are formed on the inclined surface (4a) rather than 5a).

  As shown in the cross-sectional view of FIG. 12, the thickness of the fiber collection net (27) is smaller than the net convex part (21) because the net concave part (22) is thinner, so the net convex part (21) has a suction force (26c). In comparison, a strong suction force (26a, 26b) is applied to the net recess (22) having a smaller resistance. Therefore, compared to the concave portion (1) of the air laid nonwoven fabric (10) corresponding to the net convex portion (21), the inclined surface of the convex portion (2) of the air laid nonwoven fabric (10) corresponding to the net concave portion (22) ( In 4a) and the top part (4b), there are many protruding fibers (5) in which short fibers protrude randomly from the surface (FIG. 13).

  Next, heat treatment is performed at a temperature at which the deposited heat-adhesive fiber sufficiently exhibits its bonding effect, that is, a temperature 15 to 40 ° C. higher than the melting point of the adhesive component of the heat-adhesive fiber. As a result, the heat-adhesive fibers are heated and melted to form the sheet main body (7) including the short fibers having a network structure fixed by heat-sealing with each other. That is, the sheet body (7) includes a concave portion (1) and a convex portion (2) having shapes corresponding to the net convex portion (21) and the net concave portion (22), respectively, and the concave portion (1) and the convex portion (2). The fiber density ratio is 1: 0.8 to 1.2. The inclined surface (4a) formed between the center of the raised surface (4) and the valley surface (3), and the short fibers constituting the sheet body (7) protrude outward from the inclined surface (4a). The airlaid nonwoven fabric (10) of the present invention having the fiber (5) on the raised surface (4) of the convex portion (2) is obtained.

  The size of the many net recesses (22) or openings of the fiber collection net (27) corresponds to the nonwoven fabric sheet having a three-dimensional pattern to be obtained. In the case of a shape, the minor axis or the major axis is used. In the case of a polygon, the diagonal is 1 to 20 mm, preferably 2 to 15 mm. The depth of the net recess (22) or opening is about 0.5 to 12 mm (corresponding to the height of the protrusion (2)). Here, “many” means a large number of net recesses (22) or openings corresponding to the unevenness of the air-laid nonwoven fabric sheet to be obtained, and cannot be quantitatively defined. Considering the strength and durability of the fiber collection net (27), a fiber collection net having a structure of two or more layers may be used.

  The air permeable sheet placed on the net is preferably a knitted fabric with easy design of recesses or openings. For example, flat knitted, flat knitted deformed tissue, rib knitted, rib knitted deformed tissue, double knitted, double knitted deformed tissue, pearl Weft knitted fabrics such as knitted fabrics and pearl knitted fabrics, warp knitted fabrics such as tricot knitted fabrics, russell knitted fabrics, and miranese knitted fabrics can be used. In addition, as long as it has a recessed part or opening, a woven fabric, a net | network, and a nonwoven fabric may be sufficient.

In addition, when using a chemical binder resin in the manufacturing method of the airlaid nonwoven fabric of this invention, a hot-melt-adhesive, a latex adhesive, and an emulsion type | system | group adhesive on a deposited web for every web formation (or the whole deposited web). What is necessary is just to spray or apply | coat chemical binder resin, such as an agent and a resin powder adhesive agent. The components of the chemical binder resin include polyolefin, polyvinyl acetate, polyacrylate ester, synthetic rubber, polyurethane, epoxy resin, and thermosetting resin. The amount of the chemical binder resin used is usually ² to 100 g / m ² , preferably 4 to 50 g / m ² in terms of solid content, and is determined within a range that does not cause bonding of heat-bonding fibers or pulp fibers or peeling of each layer. It is done.

  The air-laid nonwoven fabric of the present invention can be provided with functional processing such as deodorant, antibacterial agent, fragrance, moisturizer, colorant, hydrophilic agent, water repellent. The processing method is a method of mixing fibers previously imparted with a function, mixing a powdery agent, or spraying or impregnating a liquid agent. The nonwoven fabric produced by the airlaid method can three-dimensionally orient the fibers at random in the flow direction, width direction and thickness direction of the nonwoven fabric. Since these are thermally bonded, delamination does not occur. Moreover, since the non-woven fabric manufactured by the airlaid method has good uniformity, there is little variation in performance.

The airlaid nonwoven fabric sheet of the present invention is mainly composed of heat-adhesive fibers and has a total basis weight of 16 to 800 g / m ² , preferably 20 to 300 g / m ² . If it is less than 16 g / m ² , the strength of the nonwoven fabric is lowered, and practical problems such as manufacturing processability and merchandise handling tend to occur. When it exceeds 800 g / m ² , the sheet is cured, and the absorbent article has a poor touch and causes a practical problem.

  The air-laid nonwoven fabric sheet having a three-dimensional pattern of the present invention has a large number of uneven portions, the ratio of the fiber density of the recessed portions to the protruding portions is 1: 0.8 to 1.2, and the weight ratio of the recessed portions to the projected portions. Is 1: 1.2-20, and the ratio of the surface area of the concave portion to the convex portion is 1: 1.5-10. When the airlaid nonwoven fabric sheet of the present invention is used as a top sheet of an absorbent article, the surface of the convex portion has a small contact area with the skin, so that the skin is less irritating and the wet feeling caused by the discharged liquid is small. The feeling is reduced. On the other hand, the surface of the recess has a smooth transition of the liquid to the absorption layer. In addition, if applied to various interpersonal wipers and objective wipers, the unevenness of dust and dirt is improved by unevenness, and if applied to a drip absorbent sheet, wetback is reduced, so the freshness maintenance effect of fresh fish and meat is increased, In addition, it is also effective for various air-permeable packaging materials, cushioning materials, adsorbent sheets, volatile substances such as fragrances, air filters, draining bags, tea packs, coffee filters, lye removal sheets, and the like.

  Since the fiber density of the concave and convex portions is approximately uniform, the density ratio is 1: 0.8 to 1.2, preferably 1: 0.9 to 1.1. In order to make this range, when the air laid sheet is formed, the spinning air amount and the air suction amount under the net may be appropriately optimized.

  Since the airlaid nonwoven fabric sheet of the present invention has a substantially uniform fiber density as a whole, the basis weight corresponding to the concave portion is consequently smaller than that of the convex portion. As a result, the basis weight ratio between the concave and convex portions is 1: 1.2 to 20, preferably 1: 1.5 to 10. In order to be within this numerical range, it is achieved by adjusting, for example, the thickness of the fiber collection net and the overall sheet weight corresponding to the convex portion. Note that the basis weights of the concave and convex portions are each measured by punching with a small punch. If the ratio is less than 1: 1.2, it is difficult to obtain the performance characteristics obtained by the recesses. If the ratio exceeds 1:20, the recesses become high, and the nonwoven fabric sheet tends to be crushed or damaged, which is not practical.

An embodiment in which a gas containing oil mist is passed through the air-laid nonwoven fabric (10) of the present invention will be described below.
The gas flow (8) shown in FIG. 11 due to suction, blowing, etc., is evenly dispersed and flows along the inclined surface (4a) when it collides with the top (4b) of the projection (2). The inclined surface (4a) has a number of protruding fibers (5), and in particular, is inclined toward the top (4b) side of the raised surface (4) with respect to the perpendicular (V) (FIG. 3) of the inclined surface (4a). Since the second protruding fiber (5b) is included in a large amount, the protruding fiber (5) becomes a viscous oil mist resistor and suppresses the gas flow (8). At this time, a part of the gas is introduced into the convex part (2) while separating the oil mist through the gap (15) of the inclined surface (4a) (8a). The other part of the gas continues to flow along the inclined surface (4a) (8b), and the oily mist is filtered off by the protruding fibers (5) on the inclined surface (4a) from the gap (15) to the convex part (2 ) (8a '). The remaining gas further flows on the inclined surface (4a) (8b ′), part of the inclined surface (4a) into the convex portion (2), and the other remaining becomes a small amount of gas flow to form the concave portion (1 ) Is reached (8b ″).

  As described above, since the convex part (2) has the top part (4b), the air flow (8) is not concentrated on one pole, but is uniformly distributed over the entire inclined surface (4a) as a collected matter. The entire surface can be filtered without accumulating part of the oil mist. The top portion (4b) can obtain this effect even if it has the curved surface shape of FIG. 11 (FIG. 7B) or the apex shape having the apex (FIG. 7A). In addition, the inclined surface (4a) is not a smooth surface but protrudes from the protruding fibers (5), and in particular includes many second protruding fibers (5b) inclined toward the top (4b). It becomes a body and it is easy to collect oil mist. In the inclined surface (4a), continuous filtration is continued, and gas is continuously introduced from the inclined surface (4a) into the convex portion (2) (8a, 8a ′, 8a ″), so that the convex portion (2) and Three-dimensional filtration is possible using the entire volume of the sheet main body (3), that is, as shown in Fig. 11, the oil component (19) can be uniformly captured by the entire convex portion (2). When the gas reaches the valley surface (3), the amount and speed of the gas are extremely reduced (8b "), and the concentration of filtration on the valley surface (3) of the recess (1) can be suppressed.

  Although FIG. 11 shows an embodiment in which a gas is passed through the airlaid nonwoven fabric (10) of the present invention, not only a gas but also a liquid can be treated in the same manner, and similar effects can be obtained.

[Example A]
Examples of air-laid nonwoven fabric (10, 20) according to the present invention will be described in comparison with comparative examples.

[1] Production of air-laid nonwoven fabric (10) (single layer) of the present invention (Examples 1 to 8)
<Example 1>
A heat-adhesive fiber (heat) having a fineness of 1.7 dtex and a fiber length of 3 mm having a polyethylene sheath and a polyethylene terephthalate core (PE / PET) on a resin fiber collecting net (27) having a net recess (22). Adhesive core-sheath type composite fiber (made by Teijin Ltd., product name TJ04V4) is deposited, heated at 147 ° C, and the fibers are heat-sealed, and the concave portion (1) and the convex portion (2) are one of the main An airlaid nonwoven fabric (10) having a surface (7a) was produced (Example 1). In Example 1, the fiber density ratio of the concave portion (1) to the convex portion (2) was 1: 0.97 and the surface area ratio was 1.65, the concave portion (1) fiber density was 0.033, the basis weight was 80 g / m ² , FIG. 6 is a sheet having a thickness of 1.8 mm, an elliptical convex portion (2) having a major axis of 3 mm, a minor axis of 2.5 mm, and a height of 0.9 mm, and an inclined surface (4a) and a protruding fiber (5). An airlaid nonwoven fabric (10) equivalent to (b). The thickness was measured with a digital thickness measuring instrument FS-60DS (measurement terminal 50 mmφ, measurement load 3 g / cm ² ) manufactured by Daiei Kagaku Seisakusho Co., Ltd. `` Weight '' is the basis weight including the concave portion (1) and the convex portion (2), `` Thickness '' is the thickness of the entire sheet, `` Height '' is from the concave portion (1) trough (3) to the convex portion (2) top ( Each represents the height up to 4b), and so on.

<Example 2>
An airlaid nonwoven fabric (10) was produced by the same method and heat-bonding fiber as in Example 1 (Example 2). Example 2 has a fiber density ratio of 1.03 and a surface area ratio of 1: 1.57 between the concave portion (1) and the convex portion (2), a concave portion (1) fiber density of 0.062, a basis weight of 80 g / m ² , FIG. 6A shows a sheet having a thickness of 2.4 mm, a rhombus convex portion (2) having a major axis of 15 mm, a minor axis of 7 mm, and a height of 2 mm, and an inclined surface (4a) and protruding fiber (5). Equivalent airlaid nonwoven fabric (10).

<Example 3>
Except using heat-adhesive fiber (product name: TJ04B5, manufactured by Teijin Ltd.) with a fineness of 1.7 dtex and a fiber length of 5 mm having a sheath of isophthalic acid copolymer polyester and a core of polyethylene terephthalate (low melting point PET / PET) An airlaid nonwoven fabric (10) was produced in the same manner as in Example 1 (Example 3). Example 3 has a fiber density ratio of the concave portion (1) to the convex portion (2) of 1: 1.05 and a surface area ratio of 1: 1.51, a concave portion (1) of a fiber density of 0.123, a basis weight of 80 g / m ² , An airlaid nonwoven fabric (10 mm) having a rhombus convex part (2) having a major axis of 15 mm, a minor axis of 7 mm, and a height of 1.7 mm, and having an inclined surface (4a) and protruding fiber (5). ).

<Example 4>
Example 1 except that a heat-adhesive fiber having a fineness of 0.2 dt having a polyethylene sheath and a polypropylene core (PE / PP) and a fiber length of 3 mm (product name Airimo QCE-K, manufactured by Ube Eximo Co., Ltd.) was used. An airlaid nonwoven fabric (10) was produced by the method described in Example 4 (Example 4). Example 4 has a fiber density ratio of the concave portion (1) to the convex portion (2) of 1: 1.04 and a surface area ratio of 1: 3.94, a concave portion (1) of a fiber density of 0.183, a basis weight of 80 g / m ² , An airlaid nonwoven fabric (1.1 mm thick) having an elliptical convex part (2) having a major axis of 5 mm, a minor axis of 3 mm, and a height of 0.8 mm, and an inclined surface (4a) and fluffy fibers (5). 10).

<Example 5>
An airlaid nonwoven fabric (by the same method as in Example 1) except that a heat-adhesive fiber (ES fiber visions, product name ESC090) having a fineness of 35 dt and a fiber length of 5 mm having a polyethylene sheath and a polypropylene core (PE / PP) was used. 10) was produced (Example 5). In Example 5, the fiber density ratio of the concave portion (1) to the convex portion (2) is 1: 0.82 and the surface area ratio is 1: 9.36, the concave portion (1) is the fiber density of 0.026, the basis weight is 80 g / m ² , Airlaid nonwoven fabric (10) which is a sheet having a thickness of 3 mm, an elliptical convex part (2) having a major axis of 5 mm, a minor axis of 3 mm and a height of 1.9 mm, and having an inclined surface (4a) and fluffy fibers (5) It is.

<Examples 6g to 6k>
Use Example 1 the same method and the heat-adhesive fibers having a basis weight each ^{16.0g / m 2, 17.6g / m} 2, 19.2g / m 2, 20.8g / m 2 and 22.4g Airlaid nonwoven fabric (10) was produced so as to be / m ² (Examples 6g, 6h, 6i, 6j, and 6k). Example 6g has a fiber density ratio of the concave portion (1) to the convex portion (2) of 1: 1.17 and a surface area ratio of 1.165, a concave portion (1) of a fiber density of 0.032, a basis weight of 16 g / m ² , Airlaid nonwoven fabric (sheet with 1mm thickness, major axis 3mm, minor axis 2.5mm, height 0.9mm) and an inclined surface (4a) and fluffed fiber (5) 10).

<Example 7>
Using the same method and heat-adhesive fiber as in Example 1, an airlaid nonwoven fabric (10) was produced so as to have a basis weight of 800 g / m ² (Example 7). Example 7 is a sheet having a fiber density ratio of 1: 1 and a surface area ratio of 1: 1.87 between the concave portion (1) and the convex portion (2), a concave portion (1) fiber density of 0.102, and a thickness of 12 mm. An airlaid nonwoven fabric (10) having an elliptical convex part (2) of 15 mm, a minor axis of 7 mm, and a height of 3 mm, and having an inclined surface (4a) and fluffy fibers (5).

<Example 8>
In the same manner as in Example 1 except that a mixed fiber of 35% by weight of the heat-adhesive fiber used in Example 1 and 65% by weight of pulverized pulp (product name NF405, manufactured by International Paper Japan Co., Ltd.) was used. An airlaid nonwoven fabric (10) was produced (Example 8). In Example 8, the fiber density ratio of the concave portion (1) to the convex portion (2) is 1: 0.99 and the surface area ratio is 1.184, the concave portion (1) is a fiber density of 0.032, a basis weight is 80 g / m ² , Airlaid nonwoven fabric (sheet with 1.9mm thickness, long diameter 3mm, short diameter 2.5mm, height 1mm oval convex part (2) and inclined surface (4a) and fluffy fiber (5)) 10).

[2] Production of nonwoven fabric (single layer) (Comparative Examples 1 to 8)
<Comparative Example 1a>
A heat-adhesive fiber of Example 1 is deposited on a resin-made fiber collection net having no net recess, heated at 147 ° C. and thermally fused between the fibers, and a flat (flat) airlaid nonwoven fabric is obtained. Produced (Comparative Example 1a). Comparative Example 1a has a basis weight of 80 g / m ² and a thickness of 1.3 mm.

<Comparative Example 1b>
The planar air-laid nonwoven fabric of Comparative Example 1a was embossed by combining an embossing roll and an elastic roll to produce an uneven nonwoven fabric (Comparative Example 1b). Comparative Example 1b is a sheet having a fiber density ratio of 1: 4 between the concave and convex portions, a concave (1) fiber density of 0.405, a basis weight of 80 g / m ² , a thickness of 0.9 mm, a major axis of 15 mm, a minor axis of 7 mm, It is a nonwoven fabric having a rectangular convex part with a height of 0.7 mm.

<Comparative Example 1c>
A heat-adhesive fiber having a fineness of 1.7 dtex having a polyethylene sheath and a polyethylene terephthalate core (PE / PET) and a fiber length of 44 mm (made by Teijin Ltd.) The card web on which the product name TJ04CE) was deposited was heated with hot air to produce a flat (flat) thermal bond (air-through) nonwoven fabric (Comparative Example 1c). Comparative Example 1c has a basis weight of 80 g / m ² and a thickness of 1 mm.

<Comparative Example 1d>
An uneven airlaid nonwoven fabric was produced using the heat-adhesive fiber of Example 1 by the method described in Patent Document 4 of the prior art (Comparative Example 1d). Comparative Example 1d is a sheet having a fiber density ratio of 1.05 and a surface area ratio of 1.165 between the concave and convex portions, a concave fiber density of 0.038, a basis weight of 80 g / m ² , and a thickness of 1.7 mm. An airlaid nonwoven fabric having an elliptical convex portion having a major axis of 3 mm, a minor axis of 2.5 mm, and a height of 0.9 mm, and the convex portion having a flat upper surface and a concave inclined surface.

<Comparative example 2>
The air-laid nonwoven fabric (10) of Example 2 was pressed for 1 minute at 135 ° C. and 40 g / cm ² with a flat autopress machine (product number HP-125FA, HASHIMA) to produce a hot-pressed nonwoven fabric (Comparative Example 2). Comparative Example 2 is a sheet having a surface area ratio of the concave portion to the convex portion of 1: 1.32, a concave portion fiber density of 0.246, a basis weight of 80 g / m ² , a thickness of 0.5 mm, a major axis of 15 mm, a minor axis of 7 mm, and a height. It is a nonwoven fabric having an elliptical convex part of 0.25 mm.

<Comparative Example 3>
A flat airlaid nonwoven fabric (10) was produced in the same manner as in Comparative Example 1a except that the heat-adhesive fiber of Example 3 was used (Comparative Example 3). Comparative Example 3 has a basis weight of 80 g / m ² and a thickness of 1.4 mm.

<Comparative example 4>
An airlaid nonwoven fabric was produced in the same manner as in Example 1 except that a heat-adhesive fiber having a polyethylene sheath and a polypropylene core (PE / PP) having a fineness of 0.1 dt and a fiber length of 3 mm was used (Comparative Example 4). . Comparative Example 4 is a sheet having a fiber density ratio of 1.07 and a surface area ratio of 1: 2.64 between the concave and convex portions, a concave fiber density of 0.31, a basis weight of 80 g / m ² , and a thickness of 0.7 mm. It is an airlaid nonwoven fabric having an elliptical convex part having a major axis of 5 mm, a minor axis of 3 mm, and a height of 0.5 mm, and an inclined surface and protruding fibers.

<Comparative Example 5>
An airlaid nonwoven fabric was prepared in the same manner as in Example 1 except that a heat-adhesive fiber (ES fiber visions, product name ES) having a fineness of 72 dt and a fiber length of 5 mm having a polyethylene sheath and a polypropylene core (PE / PP) was used. Manufactured (Comparative Example 5). Comparative Example 5 is a sheet having a fiber density ratio of 1: 0.79 between the concave and convex portions and a surface area ratio of 1: 8.38, a concave portion (1) fiber density of 0.025, a basis weight of 80 g / m ² , and a thickness of 2.8 mm. It is an airlaid nonwoven fabric having an elliptical convex part having a major axis of 5 mm, a minor axis of 3 mm, and a height of 1.7 mm, and having an inclined surface and protruding fibers.

<Comparative Examples 6a to 6f>
Using the same method and heat-adhesive fiber as in Example 1, the basis weights were 6.4 g / m ² , 8.0 g / m ² , 9.6 g / m ² , 11.2 g / m ² and 12.8 g, respectively. Airlaid nonwoven fabrics were manufactured so as to be / m ² and 14.4 g / m ² (Comparative Examples 6a, 6b, 6c, 6d, 6e and 6f). Comparative Example 6f is a sheet having a fiber density ratio of 1: 1.23 and a surface area ratio of 1.1.65, a concave fiber density of 0.029, a basis weight of 14.4 g / m ² , and a thickness of 1 mm between the concave and convex portions. This airlaid nonwoven fabric has an elliptical convex portion having a major axis of 3 mm, a minor axis of 2.5 mm, and a height of 0.9 mm, and also has an inclined surface and protruding fibers.

<Comparative Example 7>
Using the same method and heat-adhesive fiber as in Example 1, an airlaid nonwoven fabric was produced so that the basis weight was 900 g / m ² (Comparative Example 7). Comparative example 7 is a sheet having a fiber density ratio of 1: 1 and a surface area ratio of 1: 1.87, a fiber density of recess of 0.108, a thickness of 13 mm, and a major axis of 15 mm, a minor axis of 7 mm, and a height of 3 mm. It is an airlaid nonwoven fabric which has an elliptical convex part, and has an inclined surface and a protruding fiber.

<Comparative Example 8>
An airlaid nonwoven fabric was produced in the same manner as in Example 1 except that a mixed fiber of 25% by weight of the heat-adhesive fiber of Example 1 and 75% by weight of the pulverized pulp of Example 8 was used (Comparative Example 8). Comparative Example 8 is a sheet having a fiber density ratio of the concave portion and the convex portion of 1: 1.01 and a surface area ratio of 1: 2.02, a concave portion fiber density of 0.031, a basis weight of 80 g / m ² , a thickness of 2 mm, and a major axis of 3 mm. An airlaid nonwoven fabric having an elliptical convex part with a minor axis of 2.5 mm and a height of 1.1 mm and an inclined surface.

[3] Production of air-laid nonwoven fabric (20) (two layers) of the present invention (Examples 9 to 11)
<Example 9a>
After the heat-adhesive fibers were deposited by the same method as in Example 1, the heat-adhesive fibers of Example 4 were further laminated and heated at 147 ° C. to heat-seal between the fibers. A two-layer airlaid nonwoven fabric (20) having part (2) on one main surface (7a) was produced (Example 9a). In Example 9a, the weight ratio of the first layer (11) to the second layer (12) is 62.5: 37.5, and the fiber density ratio of the concave portion (1) to the convex portion (2) is 1: 0. .88 and surface area ratio 1: 1.65, concave portion (1) fiber density 0.114, basis weight 80 g / m ² , thickness 1.2 mm, major axis 3 mm, minor axis 2.5 mm, height 0.9 mm An airlaid nonwoven fabric (20) having an elliptical convex portion (2) and an inclined surface (4a) and a protruding fiber (5).

<Example 9b>
An airlaid nonwoven fabric (10) was produced by the same method and heat-bonding fiber as in Example 9a (Example 9b). In Example 9b, the weight ratio of the first layer (11) to the second layer (12) is 62.5: 37.5, and the fiber density ratio of the concave portion (1) to the convex portion (2) is 1: 0. .97 and surface area ratio of 1: 1.5, concave portion (1) Fiber density 0.085, basis weight 80 g / m ² , thickness 2.1 mm sheet, major axis 15 mm, minor axis 7 mm, height 1.3 mm An air-laid nonwoven fabric (20) having a convex portion (2) and having an inclined surface (4a) and protruding fibers (5).

<Example 10>
A heat-adhesive fiber having a fineness of 11 dtex having a polyethylene sheath and a polypropylene core (PE / PP) and a fiber length of 5 mm (Oyama Chemical Co., Ltd.) on a resin fiber collecting net (27) having a net recess (22). ), Product name S / S 006-1) was deposited, and the heat-adhesive fibers of Example 1 were further laminated and heated at 147 ° C. to heat-seal between the fibers. A two-layer airlaid nonwoven fabric (20) having 2) on one main surface (7a) was produced (Example 10). In Example 10, the weight ratio of the first layer (11) and the second layer (12) is 62.5: 37.5, and the fiber density ratio of the concave portion (1) and the convex portion (2) is 1: 0. .95 and surface area ratio 1: 3.31, concave portion (1) fiber density 0.03, basis weight 80 g / m ² , thickness 2.7 mm sheet, major axis 3 mm, minor axis 2.5 mm, height 1.8 mm An airlaid nonwoven fabric (20) having an elliptical convex portion (2) and an inclined surface (4a) and a protruding fiber (5).

<Example 11>
After the heat-adhesive fibers were deposited by the same method as in Example 1, the heat-adhesive fibers used in the first layer (11) of Example 10 were further laminated and heated at 147 ° C. to heat the fibers. A two-layer airlaid nonwoven fabric (20) having a concave portion (1) and a convex portion (2) on one main surface (7a) was produced by fusing (Example 11). In Example 11, the weight ratio of the first layer (11) to the second layer (12) is 62.5: 37.5, and the fiber density ratio of the concave portion (1) to the convex portion (2) is 1: 1. .19 and surface area ratio of 1.165, concave portion (1) fiber density 0.027, basis weight 80 g / m ² , thickness 1.8 mm, major axis 3 mm, minor axis 2.5 mm, height 0.9 mm An airlaid nonwoven fabric (20) having an elliptical convex portion (2) and an inclined surface (4a) and a protruding fiber (5).

[4] Manufacture of airlaid nonwoven fabric (two layers) (Comparative Example 9)
After the heat-adhesive fibers were deposited by the same method as in Comparative Example 1a, the heat-adhesive fibers of Example 4 were further laminated, heated at 147 ° C., and the fibers were heat-sealed to form a flat (flat) shape. A two-layer airlaid nonwoven fabric was produced (Comparative Example 9). In Comparative Example 9, the weight ratio of the first layer to the second layer was 62.5: 37.5, the basis weight was 80 g / m ² , and the thickness was 0.9 mm.

[5] Test method About the Example and the comparative example, it tested by the following method.
[5-1] Air permeability test Using AP-360SM manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd., the air permeability was measured according to the Japanese Industrial Standard L1096A method (Fragile method). That is, after each test piece of about 200 mm × 200 mm taken from the example and the comparative example is attached to one end of a cylinder of a Frazier type tester, a suction fan and an inclination type barometer indicate a pressure of 125 Pa by an adjusting resistor. Adjust the air hole and measure the pressure indicated by the vertical barometer at that time. From the measured pressure and the type of air hole used, the amount of air passing through the test piece (cm ³ / cm ² · s) was obtained from the conversion table attached to the testing machine.

[5-2] Holding capacity test Using DFT-3T1N manufactured by Tokyo Directec Co., Ltd., gas was passed through the sheets of Examples and Comparative Examples, and the weight of the captured dust was measured and held when the pressure loss reached 150 Pa. Volume (mg). As the dust, JIS test powder (JIS Z 8901, 11 types, Kanto Loam baked product) was used.

[5-3] Dust retention amount test Each sample of Examples and Comparative Examples is punched into a circle having a diameter of 13 cm, and 11 types of JIS test powders are provided on the surface having a convex portion or the surface having no convex portion having a fluff. After 3 g was adhered and leveled, the amount of powder retained was measured after 1 minute with a 10 mm pitch wire mesh with the powder adhesion surface down.

[5-4] Oil retention test The sheets of Examples and Comparative Examples having a size of 5 cm × 5 cm were immersed in oil for 1 minute, drained with a horizontal wire mesh for 1 minute, and then the oil retention weight of the sheet was measured.

[5-5] Mist collection test Put 1 kg of unused salad oil in a pan, enclose the top and four sides of the IH cooking heater and pan with an aluminum frame, and place it horizontally on the top of an aluminum frame 70 cm higher than the pan. Each sheet of the example of 25 cm × 40 cm and the comparative example is attached, and the upper 20 cm × 20 cm opening is exhausted with a ventilation fan, and heated with an IH cooking heater with an output of 1400 W for 6 hours at 180 ° C. The amount of mist was measured and converted per 1 m ² to obtain the amount of collected mist.

[5-6] Combustion test Based on the 45 ° micro burner method (A-1 method) of the Japanese Industrial Standard fiber product flammability test method (JIS L-1091), the degree of the spread of combustion in the examples and comparative examples (Combustion length and combustion area), residual flame and residual time were measured, and the combustibility category was calculated from the measured values. Here, “burning area” is the total area of the portion destroyed by combustion or pyrolysis under the prescribed test conditions, “burning length” is the maximum length of the portion destroyed by combustion or pyrolysis, “ “Afterflame time + residual time” represents the time from the end of heating until the red heat of the test piece stops.

[5-7] Tensile strength test For the examples and comparative examples, the tensile strength was measured with a force tester (A & D product number MCT-2150) at a sample width of 50 mm, a chuck interval of 100 mm, and a tensile speed of 300 m / min. It was measured.

[6] Test results and discussion The compositions and test results of the examples and comparative examples are shown in Tables 1 to 4 and discussed below. The fineness unit “t” shown in the “Fiber composition” column of the table means “dtex”.

[6-1] Air permeability From Tables 1, 2, and 4, Examples 1, ² , 5, 6 g, 10 and 11 according to the present invention show excellent air permeability of 170 cc / cm ² / sec or more, and air filters It is suitable for. On the other hand, Comparative Example 4 with a low fineness (0.1 dtex), Comparative Example 7 with a high basis weight (900 g / m ² ), and Comparative Example 9 with a flat two-layer structure have low air permeability values of 35 cc / cm ² / sec or less. Is not suitable for filters.

[6-2] Retention Capacity From Table 1, Examples 1 and 2 showed an excellent retention capacity value of 588 mg or more, and Comparative Example 1b showed a low retention capacity value of 140 mg. That is, in Comparative Example 1b of hot embossing, as described in the prior art (FIG. 15), the flow concentrates in the concave portion, but since it is heated and compressed, clogging occurs early and it is not suitable for a filter. On the other hand, since the airlaid nonwoven fabric (10) of the present invention is not compressed on the surface, the airlaid nonwoven fabric (10) is filtered using the entire surface and the entire volume.

[6-3] Dust retention amount From Tables 1, 2 and 4, Examples 8, 9a and 9b show particularly excellent dust retention values of 1.23 g / sheet or more. 7 and 11 also showed a good dust holding value of 0.61 g / sheet or more. In the present invention, since the surface is fluffy and the protruding surface (4a) has many protruding fibers (5) protruding on the inclined surface (4a), it is easy to capture and hold dust. Comparative Examples 1a, 3 and 9 for flat, Comparative Examples 1b and 2 for hot embossing and pressing, Comparative Example 1d having a flat convex upper surface and a concave inclined surface, low fineness (0.1 dtex) and high fineness (72 dtex) Comparative Examples 4 and 5 and Comparative Example 6f with a low basis weight (14.4 g / m ² ) showed a low dust holding value of 0.39 g / sheet or less.

[6-4] Oil retention amount From Tables 1, 2 and 4, Example 7 having a large basis weight of 800 g / m ² and Example 10 using a fiber having a fineness of 11 dtex for the first layer (11), A particularly excellent oil retention value of 2154 g / m ² or more was exhibited. Examples 1, 2, 3, 5, 8, 9b and 11 also showed good oil retention values of 1016 g / m ² or more. In the said Example, since a considerable amount of oil can be hold | maintained, it is preferable as a filter for ventilation fans which capture | acquires an oil absorber or oil mist. Comparative Examples 1b, 2, 4 and 6f show a low oil retention value of 488 g / m ² or less, and when used in a filter for a ventilation fan, there is no oil retaining power, so even if it is retained, oil will be released early. There is a risk of falling and is not suitable for ventilation fans.

[6-5] Mist collection amount From Tables 1, 2 and 4, Examples 1, 2, 3, 8, 9a and 9b show excellent mist collection values of 0.11 g / sheet or more, Preferred as a ventilation fan filter. In Comparative Example 1b of hot embossing and Comparative Example 2 of hot press, the surface and the inside are compressed at the time of manufacture, so that oil cannot be sufficiently introduced and absorbed from the surface of the nonwoven fabric and cannot be retained. The following values of low mist collection were shown.

[6-6] Combustion performance From Tables 1 and 2, in Examples 1, 2, 3 and 6g, the combustion length is 7.6 cm or less, the combustion area is 10.9 cm ² or less, and the combustion classification is 3 The numerical values of the combustion performance are shown. This is expected to have a small carbonization distance and carbonization area because the number of fibers in the recess (1) is small. Comparative Example 1b for hot embossing and Comparative Example 2 for hot press showed numerical values with low combustion performance, both with a combustion length of 26.5 cm or more, a combustion area of 46 m ² or more, and a combustion classification of 1. This is probably because the fibers are dense and the distance between the fibers is short.

[6-7] Tensile strength Hereinafter, the tensile strength will be considered in the machine direction (MD) of the nonwoven fabric in a dry (DRY) state. From Table 3, Examples 6g-6k showed the value of the outstanding tensile strength of 1.05 kgf / 50mm or more, and Example 6a-6f showed the value of the low tensile strength of 0.58 kgf / 50mm or less. For this reason, the lower limit value of the basis weight of the air-laid nonwoven fabric having high tensile strength is considered to be 16.0 g / m ² (Example 6g). From Tables 1, 2 and 4, Example 7 shows a particularly excellent tensile strength value of 50 kgf / 50 mm or more, and Examples 1-4, 9a and 9b show good tensile strength values of 8.9 kgf / 50 mm or more. showed that. Comparative Examples 5, 6f and 8 exhibited low tensile strength values of 0.9 kgf / 50 mm or less. Comparative Example 8 is also unsuitable for a filter because of the short fibers and pulp falling off.

[7] Conclusion From the above test results and discussion, Examples 1 and 2 are for all test items [6-1] to [6-7], and Example 3 is for all test items except for air permeability. It was found to be an excellent value and very high performance filter material. Examples 7, 8, 9a, 9b and 11 also showed excellent values in 3 out of all 5 items tested, and thus proved to be high performance filter materials. The above examples are considered to be universally usable as filtering materials for all uses. Since Example 4 has high tensile strength and thin fibers, it is suitable for a business use filter (for air conditioners such as clean rooms, dust masks, dust collectors or vacuum cleaners). Examples 5 and 10 have air permeability and Because the oil retention is high, it is suitable for ventilation fan filters in factories that use a lot of oil. Example 6g has high air permeability and exhibits excellent combustion performance, so it is suitable for ventilation fan filters in kitchens and kitchens that use fire. Furthermore, since Examples 6g to 6k have higher tensile strength than Comparative Examples 6a to 6f, it was found that they are suitable for commercial filters under high pressure or high water pressure conditions. As described above, all the embodiments 1 of the present invention, in which the inclined surface (4a) of the convex portion (2) is provided with the protruding fiber (5), particularly the first protruding fiber (5), and the apex (4b). ~ 11 were found to have excellent filtration properties. According to the examples, preferred ranges of the physical properties of the air-laid nonwoven fabric of the present invention are shown below.

  About the range of the fiber density ratio of a recessed part (1) and a convex part (2), the airlaid nonwoven fabric (10) of a single layer from Table 1 and Table 2 is 1: 0.82 (Example 5)-1: 1.17. (Example 6g) is preferable. From Table 4, the air-laid nonwoven fabric (20) having a two-layer structure is preferably 1: 0.88 (Example 9a) to 1: 1.19 (Example 11). Therefore, it was found that the air-laid nonwoven fabrics (10, 20) having a single layer and a double structure have substantially the same fiber density ratio. Regarding the fiber density range of the recess (1), from Table 1 and Table 2, the single-layer air-laid nonwoven fabric (10) is preferably 0.026 (Example 5) to 0.183 (Example 4). The air-laid nonwoven fabric (20) having a structure is preferably 0.027 (Example 11) to 0.114 (Example 9a). In all the embodiments of the present invention having a low density of 0.2 or less, a straight path (9) connecting a large number of valley surfaces (3) and a large number of protrusions (2) arranged in parallel to the straight path (9) The airlaid nonwoven fabric (10, 20) can be torn and cut easily and cleanly by hand.

Regarding the range of fineness, from Table 1 and Table 2, the air-laid nonwoven fabric (10) having a single layer is preferably 0.2 dtex (Example 4) to 35 dtex (Example 5), and from Table 4, the air-laid nonwoven fabric (20) having a two-layer structure. Is preferably 0.2 dtex (Examples 9a and 9b) to 11 dtex (Examples 10 and 11). Regarding the range of the thermoplastic fiber content, from Tables 1 and 2, the single-layer air-laid nonwoven fabric (10) is preferably 35% by weight (Example 8) to 100% by weight (all examples other than Example 8). Furthermore, about the shape of a convex part (2), the airlaid nonwoven fabric (10,20) from Table 1, Table 2, and Table 4 is an ellipse (Example 1, 4, 5, 6g-6k, 8, 9a, 10 and 11). And rhombuses (Examples 2, 3, 7 and 9b) are preferred.
[Example B]

Hereinafter, the evaluation of the objective wiper and the evaluation of the adsorptive sheet were performed as follows.
<Evaluation of dry objective wiper>
As a dry objective wiper, a floor wiping test was conducted based on the following flooring wiper test method. The test method cut | disconnected the nonwoven fabric sheet of the following Example and the comparative example into 200 mm x 300 mm, and was set as the flooring wiper. It is spread separately on the same type of cleaning tool, and then 4 kinds of JIS test powder, 7 kinds of JIS test powder, cotton linters, and 10 pieces spread on the floor. Each hair was wiped and cleaned, and the weight of each substance (the number in the hair) before and after the cleaning tool was reciprocated twice was measured, and the reduction rate was measured. Each test was performed three times, and the average value was calculated. The physical properties of the nonwoven sheet are shown in Table 5.

<Evaluation of adsorbent sheet (ammonia deodorization rate)>
As an adsorbent sheet, an ammonia gas adsorption test was performed based on the following test method. First, airlaid nonwoven fabric sheets were produced as the following examples and comparative examples. Next, 30 μl of 9% aqueous ammonia solution was dropped into a 20 L Tedlar® bag, which was then sealed and allowed to stand for 24 hours to vaporize ammonia. Residual ammonia in the gas collected from the initial ammonia concentration and the 65 mm × 160 mm × 2 sheets of each of the Example and Comparative Example in a 3 L Tedlar® bag and left for 24 hours at room temperature The concentration was measured using a gas detector tube. The deodorization rate was calculated | required from the following formula | equation. Each test was performed three times, and the average value was calculated.
Deodorization rate = {1− (residual ammonia concentration) / (initial ammonia concentration)} × 100 (%)
Various physical properties of the nonwoven sheet are shown in Table 6.

<Evaluation of lye removal sheet (evaluation of lye capture amount)>
Moreover, it tested based on the following test method as an lye extract sheet. Put 500cc of water, 20g of tallow (beef) and 180g of red beef into an aluminum pan with a diameter of 20cm and a depth of 8.5cm. Cutting and placing two types of Example and Comparative Example at the same time. This state was set as the first time, and after cooking for 10 minutes, the cooking sheet was taken out, air-dried, and the amount of ash solids was measured and then calculated by the following equation (1). Next, as the second time, the lye removal sheet is replaced, and after the simmering for 10 minutes, the cooking sheet is taken out and air-dried to measure the amount of lye solids, and then the following formula (1) Calculated by Here, the lye capture amount W (g / m ² ) was calculated from the following equation.
W = (W2-W1) (1)
here,
W1: Weight of lye removal sheet before use (g)
W2: Weight of air dried lye removal sheet after use (g)
The physical properties of the nonwoven sheet are shown in Table 7.

Example B1 (Evaluation of absorbent article)
3-4 (however, for the sake of convenience, the convex part is spherical), a collection net made of polyethylene terephthalate (PET) is placed on a commercially available tricot knitted fabric (see FIG. 1 (however, for convenience, the opening is Sphere), the opening is elliptical, the major axis is 3.0 mm, the minor axis is 2.5 mm, the openings are arranged in a staggered pattern, and the number is 6.60 / cm ² ). A net that was laminated and integrated was used. On top of this, 70% by weight of heat-adhesive conjugate fiber made of sheath PE (polyethylene) / core PET (manufactured by Teijin Ltd., product name TJ04V4, 1.7 dtex × 3 mm), pulverized pulp (manufactured by Weyerhaeuser, product name NB-) 405) is mixed at a ratio of 30% by weight and heated at 147 ° C. in a heat oven at 45 ° C. to produce 45 g / m ^2. An air laid nonwoven fabric sheet having a three-dimensional pattern on one side and having a height of 1.1 mm was obtained. As a result of actually measuring the obtained sheet, the ratio of the fiber density between the concave portion and the convex portion was 1: 0.94, and the basis weight ratio between the concave portion and the convex portion was 1: 1.9. In addition, as a result of calculating the major axis of the elliptical convex part from 3.0 mm, the minor axis from 2.5 mm, and the height from 1.1 mm, the surface area ratio of the concave part to the convex part is 1: 1.6, and the concave part to the convex part. The projected area ratio of the part was 1: 0.63. Here, when the surface sheet of a commercially available sanitary product was peeled off and then replaced with this sheet with the convex portion as the surface, menstrual blood could be absorbed quickly and was difficult to reverse. Moreover, the smooth feeling of the skin was good, the touch was good, and it was useful.

Example B2 (Evaluation of absorbent article)
Conditions except that the opening of the tricot knitted fabric has an elliptical spherical shape, the major axis is 5.5 mm, the minor axis is 2.2 mm, the openings are arranged in a staggered pattern, and the number is 4.41 / cm 2. In the same manner as in Example B1, an air-laid nonwoven fabric sheet having a three-dimensional pattern on one side and having a convex portion height of 2.6 mm was obtained. As a result of actually measuring the obtained sheet, the ratio of the fiber density between the concave portion and the convex portion was 1: 1.02, and the basis weight ratio between the concave portion and the convex portion was 1: 4.5. In addition, as a result of calculating the major axis of the elliptical convex part from 5.5 mm, the minor axis from 2.2 mm, and the height from 2.6 mm, the surface area ratio of the concave part to the convex part is 1: 9.5, and the concave part to the convex part. The projected area ratio of the part was 1: 0.72. Here, when the surface sheet of a commercially available sanitary product was peeled off and then replaced with this sheet with the convex portion as the surface, menstrual blood could be absorbed quickly and was difficult to reverse. Moreover, the smooth feeling of the skin was good, the touch was good, and it was useful.

Comparative Example B1 (Evaluation of Absorbent Article)
As an airlaid collection net, a normal net (only the fiber collection net 11 in FIG. 2) in which no tricot knitted fabric was laminated was used, and the other conditions were the same as in Example B1. A sheet having a thickness of 0.8 mm and flat on both sides was obtained. Similar to Example B1, the surface sheet was peeled off from the commercially available sanitary product and replaced. As a result, absorption of menstrual blood was slower than in Examples B1 and B2, and there was no convexity and depression, so there was a feeling of clinging to the skin. And the feeling of smoothness was small.

Comparative Example B2 (Evaluation of absorbent article)
As an air laid collection net, as disclosed in Japanese Patent No. 5024833, “a fine pore provided in a discharge portion is conveyed while uniformly dispersing a fiber mainly composed of a predetermined amount of defibrated thermal adhesive fiber in an air flow. The fiber blown from the metal is a metal or plastic fiber collection net installed in the lower part, dropped onto the fiber collection net locally provided with a projection made of a synthetic resin, the net While suctioning air at the bottom, the fiber is deposited on the net, and if necessary, after repeating this operation a plurality of times, the temperature is 15 to 40 ° C. higher than the melting point of the adhesive component of the heat-bondable fiber. The other conditions were the same as in Example B1. A sheet having a thickness of 1.0 mm, in which the depressed portion on one side is elliptical, was obtained. When the surface sheet was peeled off from the commercially available sanitary product and replaced in the same manner as in Example B1, water was slightly retained in the depressed portion compared to Example B1, and the smooth feeling was small. This seems to be because the contact area to the skin is large because the comparative example B2 has a large number of concave portions as compared to the case where the example B1 has a large number of convex portions.

Comparative Example B3 (Evaluation of absorbent article)
The same thing as comparative example B1 was embossed by the combination of an embossing roll and an elastic roll at a post process, and the uneven sheet | seat was obtained. The embossed shape was the same as in Example B1. As in Example B1, the surface sheet was peeled off from the commercially available sanitary product and replaced. As compared with Example B1, the concave portions were higher in density than the convex portions. The feeling I did was small.

Example B3 (Evaluation of dry objective wiper)
Using the same collection net and tricot knitted fabric as in Example B1, a net obtained by laminating and integrating both was used. On top of this, 70% by weight of heat-adhesive conjugate fiber made of sheath PE (polyethylene) / core PET (manufactured by Teijin Ltd., product name TJ04V4, 1.7 dtex × 3 mm), pulverized pulp (manufactured by Weyerhaeuser, product name NB-) 405) is mixed at a ratio of 30% by weight and heated at 147 ° C. in a thermal oven at 30 ° C. to produce 30 g / m ^2, and fiber-to-fiber bonding is generated. An air laid nonwoven fabric sheet having a three-dimensional pattern on one side and having a thickness of 1.0 mm was obtained. Here, the evaluation as a flooring wiper was implemented by the method shown above. The results are shown in Table 1. As compared with Comparative Example B4 and Comparative Example B5, superiority was seen in the reduction rate of each substance, that is, the dust removal rate, due to the effect of scraping by the convex surface.

Example B4 (Evaluation of dry objective wiper)
Using the same collection net and tricot knitted fabric as in Example B2, a net obtained by laminating and integrating both was used. Other conditions were the same as in Example B3. An airlaid nonwoven fabric sheet having a concave and convex portions on one side and a convex portion having a thickness of 1.9 mm and having a three-dimensional pattern on one side was obtained. Here, the evaluation as a flooring wiper was implemented by the method shown above. The results are shown in Table 5. As compared with Comparative Examples B4 and B5, superiority was seen in the reduction rate of each substance, that is, the dust removal rate, due to the effect of scraping by the convex surface. It should be noted that the dust removal rate was superior to that of Example B3, which is presumably because the uneven shape was larger than that of Example B3.

Example B5 (Evaluation of dry objective wiper)
Using the same collection net and tricot knitted fabric as in Example B2, a net obtained by laminating and integrating both was used. On top of this, 70% by weight of heat-adhesive conjugate fiber made of sheath PE (polyethylene) / core PET (manufactured by Teijin Ltd., product name TJ04C2, 56 dtex × 5 mm), pulverized pulp (product name NB-405, manufactured by Weyerhaeuser) Is mixed at a ratio of 30% by weight and heated at 147 ° C. in an air oven method so as to be 30 g / m ² , causing interfiber bonding, and having concave and convex portions on one side. An air laid nonwoven fabric sheet having a thickness of 1.9 mm and having a three-dimensional pattern on one side was obtained. The evaluation as a flooring wiper was implemented by the method shown above. The results are shown in Table 1. As compared with Comparative Example B4 and Comparative Example B5, superiority was seen in the reduction rate of each substance, that is, the dust removal rate, due to the effect of scraping by the convex surface. Compared to Example B4, because the fibers were thicker, cotton linters and hair had an advantage in dust removal rate, but fine dust JIS test powder 4 types and JIS test 7 types of powders were inferior.

Comparative Example B4 (Evaluation of dry objective wiper)
As the air laid collection net, a normal net (only the fiber collection net 11 in FIG. 2) in which the tricot knitted fabric was not laminated was used, and the other conditions were the same as in Example B3. A sheet having a thickness of 0.7 mm and flat on both sides was obtained. Here, the evaluation as a flooring wiper was implemented by the method shown above. The results are shown in Table 5. As compared with Examples B3 to B5, the reduction rate of each substance, that is, the dust removal rate was inferior.

Comparative Example B5 (Evaluation of dry objective wiper)
The same thing as comparative example B4 was embossed by the combination of the embossing roll and the elastic roll in the post process, and the uneven sheet | seat was obtained. The embossed shape was the same as in Example B3. Here, the evaluation as a flooring wiper was implemented by the method shown above. The results are shown in Table 5. Although the reduction rate of each substance was slightly better than Comparative Example B4, the reduction rate of each substance, that is, the dust removal rate was inferior to Examples B3 to B5.

Example B6 (Evaluation of deodorization rate)
Using the same collection net and tricot knitted fabric as in Example B1, a net obtained by laminating and integrating both was used. On top of this, 50% by weight of heat-adhesive conjugate fiber (manufactured by Teijin Fibers Ltd., product name TJ04V4, 1.7 dtex × 3 mm) made of sheath PE (polyethylene) / core PET, pulverized pulp (manufactured by Weyerhaeuser, product name NB) the -405) were mixed at a ratio of 50 wt%, in air-laid process so as to be 60 g / m ^2, by causing interfiber bonding by heating at 147 ° C. by heat oven has a recess and a convex portion on one side, An air-laid nonwoven fabric sheet having a three-dimensional pattern on one side and having a convex thickness of 1.2 mm was obtained. Here, the adsorption performance of ammonia gas was evaluated by the method described above. The results are shown in Table 6. As compared with Comparative Examples B6 and B7, the ammonia gas adsorption performance was superior. This is considered to be due to an increase in surface area due to the uneven surface.

Comparative Example B6 (deodorant rate evaluation)
As an airlaid collection net, a normal net (only the fiber collection net 11 in FIG. 2) in which the tricot knitted fabric was not laminated was used, and the other conditions were the same as in Example B6. A sheet having a thickness of 0.9 mm and flat on both sides was obtained. Here, the adsorption performance of ammonia gas was evaluated by the method described above. The results are shown in Table 6, but the ammonia gas adsorption performance was inferior to that of Example B6.

Comparative Example B7 (Evaluation of deodorization rate)
The same thing as comparative example B6 was embossed by the combination of an embossing roll and an elastic roll at the post process, and the uneven sheet | seat was obtained. The embossed shape was the same as in Example B6. Here, the adsorption performance of ammonia gas was evaluated by the method described above. The results are shown in Table 2. As compared with Example B6, the ammonia gas adsorption performance was inferior. Although the ammonia gas adsorption performance was inferior to that of Comparative Example B6, it was considered that the density of the recesses was increased by embossing.

Example B7 (Evaluation of lye capture amount)
Using the same collection net and tricot knitted fabric as in Example B1, a net obtained by laminating and integrating both was used. On top of this, air-laid composite fiber (made by Teijin Fibers Ltd., product name TJ04V4, 1.7 dtex × 3 mm) made of sheath PE (polyethylene) / core PET is 100% by weight and airlaid so as to be 40 g / m ^2. In this method, an air-laid nonwoven fabric sheet having a three-dimensional pattern on one side having a concave part and a convex part on one side and a thickness of the convex part of 1.0 mm is obtained by heating at 147 ° C. in a thermal oven. Obtained. Here, evaluation as an lye extract sheet was carried out by the method described above. The results are shown in Table 7, and superiority was observed in terms of the amount of lye captured compared to Comparative Example B8.

Example B8 (Evaluation of lye capture amount)
Using the same collection net and tricot knitted fabric as in Example B2, a net obtained by laminating and integrating both was used. Other conditions were the same as in Example B7. An airlaid nonwoven fabric sheet having a concave and convex portions on one side and a convex portion having a thickness of 2.0 mm and having a three-dimensional pattern on one side was obtained. Here, evaluation as an lye extract sheet was carried out by the method described above. The results are shown in Table 7, and superiority was observed in terms of the amount of lye captured compared to Comparative Example B8. In addition, although superiority was seen in the point of the amount of lye captured compared with Example B7, it is considered that this is because the uneven shape is larger than Example B7.

Comparative Example B8 (Evaluation of lye capture amount)
As an air laid collection net, a normal net (only the fiber collection net 11 in FIG. 2) with no tricot knitted fabric was used, and other conditions were the same as in Example B7. A sheet having a thickness of 0.8 mm and flat on both sides was obtained. Here, evaluation as an lye extract sheet was carried out by the method described above. The results are shown in Table 7, but inferior in the amount of lye captured compared to Example B7 and Example B8.

  The air-laid nonwoven fabric of the present invention has not only the use of gas or liquid filters, but also, for example, sanitary products, disposable diapers, other absorbent articles, interpersonal wipers, objective wipers, drip absorbent sheets (fresh food rugs), and high air permeability. It can also be used for packaging materials, cushioning materials, adsorbent sheets for gas adsorption, volatilizers used for fragrances, filters, draining bags, tea packs, coffee filters, lye removal sheets.

  (1) ・ ・ Concavity, (2) ・ ・ Convex, (3) ・ ・ Valley, (4) ・ ・ Raised surface, (4a) ・ ・ Inclined surface, (5) ・ Protruded fiber, (5a ) ・ ・ First fluff fibers (5a), (5b) ・ ・ Second fluff fibers, (7) ・ ・ Sheet body, (7a) ・ One main surface, (8) ・ ・ Fluid (9) ・ ・ Straight path, (9a) ・ ・ Open end, (11) ・ ・ First layer, (12) ・ ・ Second layer, (15) ・ ・ Gap, (21) ・ Net convex Part, (22) ... net recess, (27) ... fiber collecting net,

Claims (7)

A sheet body comprising short fibers formed from thermally adhesive fibers;
A number of valley surfaces and raised surfaces alternately provided adjacent to each other on one main surface of the sheet body;
A recess having a valley surface and constituting the sheet body;
A convex portion that has a raised surface and forms a sheet body integrally with the concave portion;
In the air-laid nonwoven fabric in which the fiber density ratio between the concave and convex portions is 1: 0.8 to 1.2,
The raised surface has an inclined surface formed between the center of the raised surface and the valley surface, and protruding fibers in which short fibers constituting the sheet body protrude outward from the inclined surface,
The vertical cross-sectional shape of the inclined surface is linear or convex arc shape,
The approximate center of each raised surface has the highest apex in the vertical direction from one main surface of the seat body,
The top of each raised surface is the apex of a pointed or curved shape,
The apex of the pointed shape has an apex where the inclined surface is concentrated,
The airlaid nonwoven fabric characterized in that the top of the curved surface has a smaller surface area than the inclined surface. The inclined surface constitutes a filtration surface by a plurality of protruding fibers and gaps between the plurality of protruding fibers,
There are a plurality of first hair fibers that are inclined toward the valley surface with respect to the perpendicular to the inclined surface, and second fibers that are present more than the first hair fibers and are inclined toward the center of the raised surface with respect to the perpendicular to the inclined surface. With fur fibers,
The airlaid nonwoven fabric according to claim 1, wherein the second protruding fiber constitutes a resistor of fluid flowing on the inclined surface and guides the fluid from the gap to the inside of the sheet body. It is equipped with a straight path with many valley surfaces connected to one main surface of the seat body,
The straight path has an open end at least at one end;
The air-laid nonwoven fabric according to claim 1 or 2, wherein the fiber density of the concave portions constituting the straight path is 0.02 to 0.2.   The sheet main body is a single layer containing 30 to 100% by weight of short fibers formed from heat-adhesive fibers having a single yarn fineness of 0.2 to 60 dtex and a fiber length of 2 to 15 mm. The air-laid nonwoven fabric described in 1. The sheet body includes a first layer including part or all of the raised surface and forming one main surface of the sheet body, and a bonding surface of the first layer opposite to the one main surface of the sheet body. And at least a second layer laminated,
Either one of the first layer and the second layer includes 30 to 100% by weight of short fibers formed from heat-adhesive fibers having a single yarn fineness of 1.5 to 60 dtex and a fiber length of 2 to 15 mm,
2. The other of the first layer and the second layer contains 30 to 100% by weight of short fibers formed from heat-adhesive fibers having a single yarn fineness of 0.2 to 60 dtex and a fiber length of 2 to 15 mm. The airlaid nonwoven fabric of any one of -3. A process of dispersing the defibrated thermal adhesive fiber in an air stream and releasing it from the ejection device;
Depositing the released heat-adhesive fiber on a single layer or two or more layers of fiber collection nets having air permeability and having a large number of net recesses and net projections, while applying a suction force;
Heat-melting the deposited heat-adhesive fibers to form a sheet body including short fibers heat-sealed with each other,
The sheet body includes a concave portion and a convex portion corresponding to the net convex portion and the net concave portion, respectively, and the fiber density ratio between the concave portion and the convex portion is 1: 0.8 to 1.2.
The raised surface of the convex portion has an inclined surface formed between the center of the raised surface and the valley surface, and short fiber constituting the sheet body protrudes outward from the inclined surface,
The vertical cross-sectional shape of the inclined surface is linear or convex arc shape,
The approximate center of each raised surface has the highest apex in the vertical direction from one main surface of the seat body,
The top of each raised surface is the apex of a pointed or curved shape,
The apex of the pointed shape has an apex where the inclined surface is concentrated,
A method for producing an airlaid nonwoven fabric, wherein the top of the curved surface has a smaller surface area than the inclined surface. The process of depositing heat-adhesive fibers while applying suction is
A process in which a strong suction force is applied to the net recess compared to the net protrusion,
Forming a first protruding fiber inclined to the valley surface side with respect to the perpendicular of the inclined surface, and a second protruding fiber inclined to the center side of the raised surface with respect to the perpendicular of the inclined surface,
The method for producing an air laid nonwoven fabric according to claim 6, wherein the step of applying a strong suction force to the net recess includes a step of forming a larger number of second protruding fibers on the inclined surface than the first protruding fibers.