JP6466646B2 - Sound absorber and sound absorbing method using the same - Google Patents

Description

  The present invention provides soundproofing for buildings (for example, houses, factory houses and facilities, buildings, hospitals, schools, gymnasiums, cultural halls, public halls, concert halls, highway soundproof walls, etc.), vehicles such as automobiles, and aircraft. The present invention relates to a sound absorber that can be used as a material or a sound insulation material, and a sound absorption method using the same.

  Conventionally, as one of the soundproofing / acoustic measures for buildings such as houses, office buildings, factories, concert halls, etc., sound absorbing members having sound absorbing performance represented by glass wool and rock wool are attached to the ceiling and walls. ing. Among these, as such a sound absorbing member, a panel-like sound absorber using glass wool is widely used from the viewpoints of economy, workability, environmental safety, and the like.

  However, since the conventional panel-like sound absorbing material has a low sound absorption rate, the sound absorbing power is often insufficient particularly when considering room acoustics. Therefore, depending on the application, a method of attaching a panel-like sound absorbing material made of a porous material or the like on the sound insulating panel using a fastening material such as an adhesive, a nail, or a screw is also performed. However, sound-absorbing materials composed of porous materials such as glass wool and rock wool are generally weak in strength, and are easily damaged during transportation, loading, construction, etc., and sound-absorbing properties, particularly in the low-frequency range. Low characteristics.

  The applicant has heat-treated the non-woven fiber assembly containing the wet heat adhesive fibers with high-temperature steam, so that the wet heat adhesive fibers have a non-woven fiber structure and have a uniform adhesion rate in the thickness direction. A hard molded body (non-woven fiber structure) has been proposed (International Publication No. 2007/116676 (Patent Document 1)). Patent Document 1 describes that this non-woven fiber structure can be used as a building material board. However, the applicant has found that such non-woven fiber structure exhibits excellent sound absorption characteristics. Have proposed a good sound absorption.

  For example, in Japanese Patent Application Laid-Open No. 2010-163778 (Patent Document 2), a non-woven fiber structure including a wet heat-adhesive fiber and fixed with fibers by fusion of the wet heat-adhesive fiber and a honeycomb structure are laminated. A structural panel has been proposed. Further, for example, in JP 2013-181381 (Patent Document 3), a fiber-based sound absorbing layer, a plate material laminated on one surface of the fiber-based sound absorbing layer and having one or more openings, and the fiber system There has been proposed a sound absorbing panel including a plate-like honeycomb structure laminated on the other surface of the sound absorbing layer.

International Publication No. 2007/116676 JP 2010-163778 A JP 2013-181381 A

  In the panel-shaped (flat plate) sound absorbers proposed so far, a large area plane (a plane perpendicular to the thickness direction) is used as a sound absorbing part for sound absorption purposes, and a small area side surface is exposed. It is usual to shield with a reflector in consideration of the disturbance of sound waves due to the presence of the reflector. When evaluating the sound absorbing performance of conventional sound absorbers, it is common practice to perform the side face with a small area shielded by a reflector or the like so as not to impede the evaluation of sound absorbing properties on a large surface area. It was. For this reason, it is difficult to apply a plane having a large area to be used for sound absorption purposes to other uses, and it is difficult to give the sound absorber sufficient design. Moreover, since it is necessary to direct the plane which becomes a sound-absorbing part of a panel-shaped sound absorber to the side which is going to absorb sound, there also existed a problem that a sound absorber could not be installed using space effectively. Furthermore, in the low frequency region of 1000 Hz or less, conventionally, when the thickness is thin, there has been no sound absorber that exhibits sufficient sound absorption performance, and it has been known that sound absorption in the above region is difficult.

  The present invention has been made in order to solve the above-described problems, and the object of the present invention is to improve the design by using the side surface as a sound absorbing part, and to install the apparatus using space effectively. It is possible to provide a sound absorber and a sound absorption method that are excellent in sound absorption in a low frequency region of 1000 Hz or less, which is possible and particularly difficult in the past.

  The sound absorber of the present invention includes a sound absorber main body having at least one main surface and a reflector covering at least one of the main surfaces, and the sound absorber main body has a portion not covered with the reflector. It is characterized by that.

  In the sound absorber of the present invention, it is preferable that the sound absorber main body has a flat plate shape, and at least one of the main surfaces is covered with a reflector. In this case, only one of the main surfaces may be covered with a reflector.

  In the sound absorber of the present invention, it is preferable that the area of the portion of the sound absorber main body not covered with the reflector is smaller than the area of the portion covered with the reflector.

In the sound absorber of the present invention, it is preferable that the sound absorber body includes a porous body.
In the sound absorber of the present invention, it is preferable that the sound absorber body includes a non-woven fiber structure. In this case, it is preferable that a cross section of the fiber constituting the nonwoven fiber structure with respect to the longitudinal direction of the fiber is exposed in a portion of the sound absorber main body that is not covered with the reflector.

  The sound absorber body in the sound absorber of the present invention is preferably a laminate including a honeycomb structure in a part of the laminate.

  In the sound absorber of the present invention, it is preferable that the sound absorber body includes a laminated structure, and a cross section of the laminated structure is exposed at a portion of the sound absorber body that is not covered with the reflector.

  In the sound absorbing body of the present invention, the non-woven fiber structure preferably includes wet heat adhesive fibers, and in that case, the fibers are fixed at an adhesion rate of 1 to 85% by fusion of the wet heat adhesive fibers. Is preferred.

  The present invention also includes a sound absorber main body having at least one main surface and a reflector covering at least one of the main surfaces, the sound absorber having a portion that is not covered with the reflector. And a sound absorbing method for absorbing sound only by the portion.

  Provided is a sound absorbing body and a sound absorbing method that can improve designability, can be installed using space effectively, and are excellent in sound absorption in a low frequency region of 1000 Hz or less, which has been considered difficult in the past. be able to.

It is a figure which shows typically the sound-absorbing body 1 of the preferable 1st example of this invention. It is a figure for demonstrating the "main surface" in this invention. It is a figure which shows typically the sound absorber 11 of the preferable 2nd example of this invention. It is a figure which shows typically the sound-absorbing body 21 of the preferable 3rd example of this invention. It is a figure which shows typically the sound-absorbing body 31 of the preferable 4th example of this invention. It is a figure which shows typically the sound-absorbing body 41 of the preferable 5th example of this invention. It is a figure which shows typically the sound absorption body 51 of the preferable 6th example of this invention. It is a figure which shows typically the preferable example of installation of the sound absorber of this invention. It is a figure which shows typically the preferable example of installation of the sound absorber of this invention. It is a figure which shows typically the preferable example of installation of the sound absorber of this invention. It is a figure which shows typically the preferable example of installation of the sound absorber of this invention. It is a figure which shows typically arrangement | positioning of the sound absorber in the case of evaluation of the sound absorption performance of the sound absorber in Example 1. FIG. It is a figure which shows typically an example of the equipment for evaluating the sound absorption performance of a sound absorber. It is a figure which shows typically arrangement | positioning of the sound absorber in the case of evaluation of the sound absorption performance of the sound absorber in Example 2. FIG. It is a figure which shows typically the sound-absorbing body 101 produced in the comparative example 1. FIG. It is a figure which shows typically the sound absorption body 111 produced in the comparative example 2. FIG. It is a graph which shows the evaluation result about Examples 1-3 and Comparative Examples 1 and 2. FIG.

<Sound absorber>
FIG. 1 is a diagram schematically showing a sound absorber 1 of a preferred first example of the present invention. The sound absorber 1 of the present invention includes a sound absorber body 2 having at least two main surfaces A (A1, A2) and at least one of the main surfaces A1, A2 (in the example shown in FIG. 1, both main surfaces A1, A2). And a reflector 3 that covers A2), and the sound absorber main body 2 has portions (four side surfaces B in the example shown in FIG. 1) that are not covered with the reflector 3. Here, the example shown in FIG. 1 shows an example in which the sound absorber main body is realized in a flat plate shape. In this case, the “main surface” indicates two opposing large surfaces perpendicular to the thickness direction. . The sound absorber body in the present invention is not limited to a flat plate shape, and can be realized in various three-dimensional shapes. However, the “main surface” refers to a plurality of surfaces (plane or curved surface) formed in the three-dimensional shape. Of these, at least the surface having the largest area is indicated, and in some cases, the surface having the largest area and the surface having the second largest area are indicated. When the main surface indicates the surface having the largest area and the surface having the second largest area, the area is significantly larger than the other surfaces, such as a trapezoidal cross section as shown in FIG. This corresponds to the case where the surface having the largest area and the surface having the second largest area face each other.

  Here, FIG. 2 is a figure for demonstrating the "main surface" in this invention, and various solid shapes are typically shown. Hereinafter, the examples shown in FIG. 2 will be described to explain what the “main surface” in the present invention refers to.

  For example, as in the example shown in FIG. 2A, the main surface A is flat, but unlike the example shown in FIG. In this case, two large planes facing each other perpendicular to the thickness direction are formed (in this case, there are two planes having the largest area). In the present invention, the surface other than the main surface A is referred to as “side surface B”. The example shown in FIG. 2A has a shape having four side surfaces B in addition to the two main surfaces A.

  For example, FIG. 2B shows a cylindrical shape, and FIG. 2C shows a disk shape. In the case of a cylindrical shape, although depending on the length along the axial direction, if the area of the curved surface of the peripheral wall is larger than each circular surface perpendicular to the axial direction, the curved surface is “main surface A”. Thus, a circular surface perpendicular to the axial direction becomes a “side surface B” (having one main surface A and two side surfaces B). On the other hand, in the case of the disk shape shown in FIG. 2C, when the area of the two circular surfaces perpendicular to the axial direction is larger than the curved surface of the peripheral wall, the two circular surfaces are “Main surface A” and the curved surface become “side surface B” (having two main surfaces A and two side surfaces B).

  FIG. 2D shows a case of a quadrangular prism shape (cuboid shape). In the case of a quadrangular prism, although depending on the length in the longitudinal direction, when the area of each of the four rectangular surfaces along the longitudinal direction is larger than the two rectangular surfaces perpendicular to the longitudinal direction, The four large surfaces (the same area) are the “main surface A”, and the two rectangular surfaces perpendicular to the longitudinal direction are the “side surfaces B” (the four main surfaces A and the two side surfaces). B). Of course, as in the relationship between the columnar shape shown in FIG. 2B and the disc shape shown in FIG. 2C, two rectangular surfaces perpendicular to the longitudinal direction are along the longitudinal direction. When the area is larger than each of the four quadrangular surfaces, the two quadrangular surfaces perpendicular to the longitudinal direction are “main surfaces A”, and the four quadrangular surfaces along the longitudinal direction are “ Side B ”(having two main surfaces A and four side surfaces B).

  FIG. 2E shows a triangular prism shape. Even in the case of a triangular prism shape, depending on the length in the longitudinal direction, the area of each of the three rectangular surfaces along the longitudinal direction is larger than the two triangular surfaces perpendicular to the longitudinal direction. The three surfaces having the same area (the same area) become “main surface A”, and two triangular surfaces perpendicular to the longitudinal direction become “side surface B” (three main surfaces A and two (It has side B) (example of FIG.2 (e)). Of course, similarly to the relationship between the columnar shape shown in FIG. 2B and the disc shape shown in FIG. 2C, the areas of the two triangular surfaces perpendicular to the longitudinal direction are in the longitudinal direction. In the case where the area of each of the three rectangular faces along the area is larger, the two triangular faces perpendicular to the longitudinal direction become the “main surface A”, and the three rectangular faces along the longitudinal direction. Becomes “side B”. In addition, the two triangular surfaces in the case of the triangular prism shape may be a regular triangle shape or an isosceles triangle shape, and are not particularly limited. When the two triangular surfaces are isosceles triangles, two rectangular surfaces along the longitudinal direction each including two sides having the same length (they have the same area) And, the area is different between one side of the rectangular shape along the longitudinal direction including one side having a different length. When the three rectangular surfaces have a larger area than the two isosceles triangular surfaces, the two rectangular surfaces along the longitudinal direction each including two sides having the same length are the main surfaces. In the case of A, a case where one main surface A is formed as one quadrangular surface along the longitudinal direction including one side having different lengths can be considered.

  Furthermore, in the case of a trapezoidal cross section as shown in FIG. 2 (f) (including two planes having different sizes and four other inclined surfaces), the surface having the first largest area (of FIG. 2 (f) In the example, a lower surface) and a surface having a large area on the second surface (upper surface in the example of FIG. 2 (f)) may be referred to as “main surface A”, and the other four inclined surfaces may be referred to as “side surface B” (two Main surface A and four side surfaces B). This case corresponds to the case where the “main surface” mentioned above refers to the surface having the largest area and the surface having the second largest area. In the example shown in FIG. 2 (f), the shape in which the vertical direction is reversed with respect to the paper surface of the drawing, that is, the upper surface is the surface having the largest area and the lower surface is the surface having the second largest area. May be. Further, even in the case of a trapezoidal cross section, two opposing planes having different sizes do not necessarily become the main surface A, and one of the two planes has an area smaller than at least one of the four slopes, And when the other of the two planes has the largest area, there is only one main surface A. When at least one of the four slopes has a larger area than the two planes, the slope having the largest area is the main surface A.

  In addition, the shape of the sound absorber of the present invention needs to have at least two surfaces that can distinguish the “main surface A” and the “side surface B” by the size of the area. For example, a cubic shape (FIG. 2 (g)), a spherical shape (FIG. 2 (h)), etc. in which all six surfaces have the same area are not included in the shape of the sound absorber of the present invention.

  The sound absorber 1 of the present invention covers at least one of the main surfaces A of the sound absorber main body 2 as described above with the reflector 3. FIG. 1 shows a case where the two main surfaces A (A1, A2) (upper and lower surfaces) of the flat plate-like sound absorber main body 2 are covered with the reflector 3, respectively. As the reflector 3, any conventionally known appropriate one can be used without particular limitation as long as it can reflect sound waves. For example, in the case of the reflector 3 having a flat plate shape (or a sheet shape) as shown in FIG. Various inorganic face materials and organic face materials can be used.

  Examples of the inorganic face material include gypsum board, calcium silicate plate, glass plate, metal plate (eg, aluminum plate, stainless steel, steel plate, etc.).

  Examples of the organic face material include a wood board (for example, natural wood, solid wood, plywood (laminated wood board), wood fiber board (medium density fiber board MDF, particle board, oriented strand board, insulation board, etc.) )), Synthetic resin plate (eg, polyethylene plate, polypropylene plate, polystyrene plate, polyvinyl chloride resin plate (vinyl chloride resin plate), polymethyl methacrylate plate (acrylic resin plate), polyester plate, polycarbonate resin plate, polyamide resin A non-breathable paper).

  Further, it may be an inorganic and organic composite or laminated plate material such as a vinyl chloride steel plate (polyvinyl chloride coated metal plate).

  The thickness of the reflector 3 is not particularly limited, but is preferably in the range of 0.01 to 20 mm, and more preferably in the range of 0.1 to 12 mm. This is because when the thickness of the reflector 3 is less than 0.01 mm, the reflector absorbs sound energy and the effect as the reflector tends to be small, and the thickness of the reflector 3 is 20 mm. This is because the sound absorber becomes thicker, and there is a problem in installing it on a wall surface or the like, and the lightness tends to decrease.

  The sound absorber 1 of the present invention has a portion (four side surfaces B in the example shown in FIG. 1) that is not covered with the reflector 3 of the sound absorber body 2. Thus, in the sound absorber 1 of the present invention, at least a part of the side surface of the sound absorber body 2 (and the main surface not covered with the reflector in some cases) is opened, and the opened reflector 3 The part not covered with is defined as a sound absorbing part. Thus, by covering at least one of the main surfaces A having a relatively large area among the plurality of surfaces forming the sound absorber main body with the reflector, and using the remaining surface as the sound absorbing portion, the main surface that does not participate in sound absorption can be obtained. The reflector that covers the surface can be laid out freely (for example, you can hang a picture, print a photo or painting, use a decorative plywood, put cloth, wallpaper, etc.), and improve the design of the sound absorber can do. In addition, since at least one of the main surface A having a relatively large area is not used for sound absorption, the degree of freedom of installation is increased compared to the conventional case where the main surface is used for sound absorption, and the space is used effectively. Is possible. Furthermore, as will be demonstrated in the examples described later, in the present invention, at least one of the main surfaces A having a relatively large area is not used for sound absorption, and the main surface A covered with the reflector 3 (see FIG. In the example shown in FIG. 1, by using a portion other than the two main surfaces A1 and A2) as the sound absorbing portion, it is possible to provide a sound absorbing body that is excellent in sound absorption in a low frequency region of 1000 Hz or less, which has been considered difficult in the past. it can.

  In the sound absorber 1 of the present invention, it is preferable that the area of the sound absorber body 2 not covered with the reflector 3 is smaller than the area covered with the reflector. Thereby, the sound absorption effect in a low frequency region of 1000 Hz or less can be further improved. In the example shown in FIG. 1, the reflector 3 covers the two main surfaces A1 and A2 of the sound absorber main body 2, and the total area of the reflector 3 covering the two main surfaces A1 and A2 is the reflector 3. This is larger than the total area of the four side surfaces B not covered with. In other words, the example shown in FIG. 1 corresponds to the case where the area of the sound absorber body 2 that is not covered with the reflector 3 is smaller than the area of the portion covered with the reflector. On the other hand, in the case of the sound absorber 51 of the example shown in FIG. 7 to be described later, only one main surface A1 of the two main surfaces A1 and A2 of the flat plate-like sound absorber body 2 is covered with the reflector 3. In this case, since the other main surface A2 and the four side surfaces B are not covered with the reflector, the area of the portion of the sound absorber main body 2 that is not covered with the reflector 3 is covered with the reflector. Not applicable if the area is smaller than the area of the part.

  The sound-absorbing body 2 in the present invention has a flat plate shape as in the example shown in FIG. 1, and at least one of the main surfaces A is preferably covered with a reflector. Since the sound absorber body is flat, it is easy to manufacture. If a flat reflector is used, at least one of the main surface A can be easily covered. It can be set as the design member which comprises. It can also be used on other than walls, and various installation locations such as furniture gaps and bookshelf gaps can be selected.

  Moreover, it is preferable that the sound-absorbing body main body 2 in the present invention includes a porous body. The porous body may have any number of pores such as non-woven fiber structure, honeycomb structure, glass wool, rock wool, open cell resin foam, aggregate of particles of metal, resin, etc. It can be used alone or in combination. In the example shown in FIG. 1, an example in which the sound-absorbing body 2 is realized by a three-layered porous body in which a flat honeycomb structure 5 is sandwiched between flat nonwoven fiber structures 4 is shown. ing.

  The non-woven fiber structure 4 includes a wet heat adhesive fiber from the viewpoint of achieving both sound absorption, light weight, and form retention, and the fiber is fixed by fusion of the wet heat adhesive fiber. It is obtained by causing high-temperature steam to act on the web containing the wet heat adhesive fibers, exhibiting an adhesive action at a temperature below the melting point of the wet heat adhesive fibers, and partially bonding the fibers. This non-woven fiber structure has high sound-absorbing and heat-insulating properties and shock-absorbing properties peculiar to the fiber structure, and is usually adjusted by adjusting the arrangement of fibers constituting the non-woven fiber structure and the bonding state between these fibers. Both of the bending behavior and the light weight that cannot be obtained with this non-woven fabric can be achieved.

The wet heat adhesive fiber is composed of at least a wet heat adhesive resin. The wet heat adhesive resin only needs to be able to flow or easily deform at a temperature that can be easily realized by high-temperature steam and to exhibit an adhesive function. Specifically, a thermoplastic resin that is softened with hot water (for example, about 80 to 120 ° C., particularly about 95 to 100 ° C.) and can be self-adhered or bonded to other fibers, such as an ethylene-vinyl alcohol copolymer. And vinyl alcohol polymers, polylactic acid resins such as polylactic acid, and (meth) acrylic copolymers containing (meth) acrylamide units. Furthermore, it may be an elastomer (for example, a polyolefin-based elastomer, a polyester-based elastomer, a polyamide-based elastomer, a polyurethane-based elastomer, a styrene-based elastomer, etc.) that can be easily flowed or deformed by high-temperature steam. These wet heat adhesive resins can be used alone or in combination of two or more. Of these, vinyl alcohol polymers containing α-C _2-10 olefin units such as ethylene and propylene, particularly ethylene-vinyl alcohol copolymers are preferred.

  In the ethylene-vinyl alcohol copolymer, the ethylene unit content (copolymerization ratio) is not particularly limited, but is, for example, 5 to 65 mol%, preferably 10 to 65 mol%, more preferably 20 to 55 mol%. More preferably, it is about 30-50 mol%. The saponification degree of the vinyl alcohol unit is not particularly limited, but is, for example, 90 to 99.99 mol%, preferably 95 to 99.98 mol%, more preferably 96 to 99.97 mol%. Although a viscosity average degree of polymerization can be selected as needed, it is 200-2500, for example, Preferably it is 300-2000, More preferably, it is 400-1500.

  The cross-sectional shape (cross-sectional shape perpendicular to the longitudinal direction of the fiber) of the wet heat adhesive fiber is not limited to a general solid cross-sectional shape such as a round cross-section or an irregular cross-section (flat, elliptical, polygonal, etc.) Or a hollow cross-section. The wet heat adhesive fiber may be a composite fiber formed of a plurality of resins including at least a wet heat adhesive resin. The composite fiber only needs to have a wet heat adhesive resin on at least a part of the fiber surface, but it is preferable to have a wet heat adhesive resin continuous in the longitudinal direction on the fiber surface from the viewpoint of adhesiveness. The coverage of the wet heat adhesive resin is not particularly limited, but is, for example, 50% or more, preferably 80% or more, and more preferably 90% or more.

  Examples of the cross-sectional structure of the composite fiber in which the wet heat adhesive resin occupies the surface include a core-sheath type, a sea-island type, a side-by-side type, a multi-layer type, a radial type, and a random composite type. Of these cross-sectional structures, a core-sheath structure in which the wet heat adhesive resin covers the entire surface of the fiber (that is, a core-sheath structure in which the sheath portion is made of the wet heat adhesive resin) is preferable. The core-sheath structure may be a fiber in which a wet heat adhesive resin is coated on the surface of a fiber composed of another fiber-forming polymer.

  In the case of a composite fiber, wet heat adhesive resins may be combined with each other, but may be combined with non-wet heat adhesive resins. Non-wet heat adhesive resins include water-insoluble or hydrophobic resins such as polyolefin resins, (meth) acrylic resins, vinyl chloride resins, styrene resins, polyester resins, polyamide resins, polycarbonate resins, Examples include polyurethane resins and thermoplastic elastomers. These non-wet heat adhesive resins can be used alone or in combination of two or more.

  Of these non-wet heat adhesive resins, from the viewpoint of heat resistance and dimensional stability, resins having a melting point higher than that of wet heat adhesive resins (particularly ethylene-vinyl alcohol copolymers), such as polypropylene resins and polyester resins. Resins and polyamide resins, particularly polyester resins and polyamide resins are preferred from the standpoint of excellent balance between heat resistance and fiber-forming properties. As the polyester-based resin and the polyamide-based resin, resins described in JP 2010-163778 A, JP 2010-229809 A, and the like can be suitably used.

  In the case of a composite fiber composed of a wet heat adhesive resin and a non-wet heat adhesive resin (fiber-forming polymer), the ratio (mass ratio) of both can be selected according to the structure (for example, core-sheath structure). Although not particularly limited, for example, wet heat adhesive resin / non-wet heat adhesive resin = 90/10 to 10/90, preferably 80/20 to 15/85, and more preferably 60/40 to 20/80.

  The average fineness of the wet heat adhesive fiber is not particularly limited, but can be selected from the range of, for example, 0.01 to 100 dtex, preferably 0.1 to 50 dtex, more preferably 0.5 to 30 dtex, and particularly preferably 1 to 10 dtex. is there. Although it does not restrict | limit especially about average fiber length, For example, it can select from the range of 10-100 mm, Preferably it is 20-80 mm, More preferably, it is 25-75 mm.

  The crimp rate of the wet heat adhesive fiber is not particularly limited, but is, for example, 1 to 50%, preferably 3 to 40%, and more preferably 5 to 30%. Further, the number of crimps is not particularly limited, but is, for example, 1 to 100 pieces / 25 mm, preferably 5 to 50 pieces / 25 mm, and more preferably 10 to 30 pieces / 25 mm.

  The nonwoven fiber structure may further contain non-wet heat adhesive fibers in addition to the wet heat adhesive fibers. As non-wet heat adhesive fibers, in addition to fibers composed of the non-wet heat adhesive resin constituting the composite fiber, cellulosic fibers (for example, rayon fiber, tencel fiber, acetate fiber, etc.), inorganic fibers (for example, carbon) Fiber, glass fiber, metal fiber, etc.). These non-wet heat adhesive fibers can be used alone or in combination of two or more. These non-wet heat adhesive fibers can be selected according to the desired properties. When combined with semi-synthetic fibers such as rayon, fiber structures with relatively high density and high mechanical properties can be obtained. When combined with a hydrophobic fiber such as a polyamide-based fiber, the space between the fibers increases, and the number of fibers that can freely vibrate without fusing increases, so that sound absorption can be improved. Further, the non-wet heat adhesive fiber is a composite fiber (latent crimped composite fiber) in which a phase structure is formed of a plurality of resins having different thermal shrinkage rates (or thermal expansion rates), for example, Japanese Patent Application Laid-Open No. 2010-84284. The crimped fiber described in the above may be used. The average fineness and average fiber length of these non-wet heat adhesive fibers are the same as those of the wet heat adhesive fibers.

  The ratio (mass ratio) between the wet heat adhesive fiber and the non-wet heat adhesive fiber is not particularly limited, but the wet heat adhesive fiber / non-wet heat adhesive fiber = 100/0 to 0/100, preferably 100/0 to 50. / 50, more preferably 100/0 to 70/30.

  The non-woven fiber structure (or fiber) further includes a conventional additive, for example, an additive described in JP 2010-163778 A (for example, a flame retardant) supported on the surface of the structure. Or may be contained in the fiber.

  The non-woven fiber structure (molded body) has a non-woven fiber structure obtained from a web composed of the fibers, and the shape thereof is a sheet or plate. The planar shape is not particularly limited, and may be a circular or elliptical cross section, various polygonal shapes, and the like.

  In order to have a nonwoven fiber structure having a good balance between sound absorption and light weight (low density) while having a fiber structure, the nonwoven fiber structure has a fiber structure. The arrangement state and the adhesion state need to be adjusted appropriately.

  Specifically, it is preferable that the fiber is arranged substantially in parallel with the fiber web surface and a portion where a large number of fibers are locally arranged along the thickness direction does not repeatedly exist. More specifically, when an arbitrary cross section of the fiber web of the structure is observed with a microscope, the existence ratio (number ratio) of fibers continuously extending in the thickness direction over 30% of the thickness of the fiber web. However, it may be 10% or less (particularly 5% or less) with respect to the total fibers in the cross section.

  Furthermore, the fiber adhesion rate of the non-woven fiber structure by fusion of the wet heat adhesive fibers is not particularly limited, but is, for example, 1 to 85%, preferably 2 to 50%, more preferably 5 to 35%. It is. This fiber adhesion rate indicates the ratio of the number of cross-sections of two or more fibers bonded to the number of cross-sections of all fibers in the non-woven fiber cross-section. Therefore, a low fiber adhesion rate means that a ratio of a plurality of fibers fused to each other (a ratio of fibers fused by fusing) is small.

  In the non-woven fiber structure of the present invention, it is preferable that the fibers are uniformly bonded in the thickness direction. For example, in the cross-section in the thickness direction of the plate-like non-woven fiber structure, It is preferable that the fiber adhesion rate in the region is in the above range. Further, the ratio of the minimum value to the maximum value of the fiber adhesion rate in each region (minimum value / maximum value) (ratio of the minimum region to the region with the maximum fiber adhesion rate) is, for example, 50% or more, preferably 55 to 99. %, More preferably 60 to 98%. Non-woven fiber structure with excellent hardness, bending strength, folding resistance and toughness despite the low bonding area of the fibers, because the fiber adhesion rate has such uniformity in the thickness direction The body is obtained. Furthermore, since the bonding area of the fibers is low, there are many fibers that can vibrate freely and have excellent vibration absorption.

  The fiber adhesion rate can be easily measured based on the number of bonded fiber cross sections in a predetermined region by taking a photograph of an enlarged cross section of the nonwoven fiber structure using a scanning electron microscope (SEM). However, when fibers are fused in a bundle, each fiber is fused in a bundle or at an intersection, making it difficult to observe as a single fiber, especially when the density is high. easy. In this case, for example, when the fiber structure is bonded with a core-sheath type composite fiber formed with a sheath part made of wet heat adhesive fibers and a core part made of a fiber-forming polymer, The fiber adhesion rate can be measured by releasing the adhesion of the bonded portion by means such as melting or washing and comparing it with the cut surface before the release.

  The non-woven fiber structure has high toughness and bending stress, and the maximum bending stress in at least one direction (preferably in all directions) is, for example, in the method according to JIS K7017 “Fiber-Reinforced Plastics—How to Obtain Bending Properties” It may be 0.05 MPa or more, preferably 0.1 to 30 MPa, more preferably 0.15 to 20 MPa. Furthermore, the stress (1.5 times the displacement stress) when bending to a displacement of 1.5 times the bending amount indicating the maximum bending stress is maintained at 1/10 or more of the maximum bending stress (peak stress value). , Preferably 3/10 or more, more preferably 5/10 or more.

  Since the non-woven fiber structure has a non-woven fiber structure, the non-woven fiber structure has voids generated between the fibers, and thus has high lightness. Furthermore, since these voids are continuous rather than independent voids, they also have air permeability.

The density of the non-woven fiber structure is not particularly limited as long as sound absorption can be ensured. For example, the density can be selected from the range of 0.05 to 0.5 g / cm ³ , and is larger from the viewpoint of improving sound absorption and rigidity. Although it is preferable, it is 0.07 to 0.4 g / cm ³ , preferably 0.08 to 0.3 g / cm ³ , more preferably 0.1 to 0.2 g / cm from the viewpoint of excellent balance with lightness. ³ . If the apparent density is too low, the sound-absorbing property is lowered and the rigidity is also lowered. On the other hand, if the apparent density is too high, the lightness is lowered. The basis weight is not particularly limited, but may be, for example, 50 to 10000 g / m ² , preferably 100 to 8000 g / m ² , and more preferably 200 to 6000 g / m ² .

The air permeability according to the fragile method is not particularly limited, but is 0.1 cm ³ / (cm ² · sec) or more, preferably 1 to 250 cm ³ / (cm ² · sec), more preferably 5 to 200 cm ³ / (cm ² seconds).

  In order to produce the non-woven fiber structure as described above, first, the fiber containing the wet heat adhesive fiber is formed into a web. As a method for forming the web, a conventional method, for example, a direct method such as a spun bond method or a melt blow method, a card method using melt blow fibers or staple fibers, a dry method such as an air array method, or the like can be used. Among these methods, a card method using melt blown fibers or staple fibers, particularly a card method using staple fibers is widely used. Examples of the web obtained using staple fibers include a random web, a semi-random web, a parallel web, and a cross-wrap web.

  The resulting fiber web is then sent to the next step by a belt conveyor and then exposed to superheated or high temperature steam (high pressure steam) flow to obtain a structure having a nonwoven fiber structure. That is, when the fiber web conveyed by the belt conveyor passes through the high-speed and high-temperature steam flow ejected from the nozzle of the steam injection device, the fibers are three-dimensionally bonded to each other by the sprayed high-temperature steam. In particular, since the fiber web in the present invention has air permeability, high-temperature water vapor penetrates into the inside, and a structure having a substantially uniform fusion state can be obtained.

  Specifically, the non-woven fiber structure has a temperature of 70 to 150 ° C., preferably 80 to 120 ° C., more preferably 90 to 110 ° C., and high pressure steam with respect to the fiber web at a pressure of 0.1 MPa or more, preferably Is obtained by a method of spraying at 0.2 to 1.5 MPa, more preferably 0.3 to 1 MPa, a processing speed of 200 m / min or less, preferably 0.1 to 100 m / min, more preferably 1 to 50 m / min. However, for the detailed production method, the production methods described in International Publication No. 2007/116676 and International Publication No. 2009/28564 can be used.

  The obtained non-woven fiber structure is obtained as a plate-like or sheet-like molded body, and is processed into a desired size and shape by cutting or the like, but is subjected to secondary molding by conventional thermoforming if necessary. Also good.

  The thickness of the non-woven fiber structure 4 is not particularly limited, but when sandwiching the honeycomb structure 5 as in the example shown in FIG. 1, it is preferably within a range of 1 to 50 mm, and 5 to 20 mm. It is more preferable to be within the range. If the thickness of the non-woven fiber structure 4 is less than 1 mm, the sound-absorbing property tends to decrease, and the rigidity as the sound-absorbing material tends to decrease. If the thickness exceeds 50 mm, the handleability, This is because the workability is lowered, and when used as a wall material, it is difficult to adjust the thickness with other materials, and space saving cannot be realized.

  In the sound absorber 1 of the present invention, when the sound absorber body 2 includes the non-woven fiber structure 4, the portion of the sound absorber body 2 that is not covered with the reflector 3 is the fiber constituting the non-woven fiber structure 4. It is preferable that the cross section with respect to the fiber longitudinal direction is exposed. For example, in the case of the example shown in FIG. 1, one of the two opposing side surfaces among the four side surfaces B of the flat acoustic body 2 that is not covered with the reflector 3 constitutes the nonwoven fiber structure 4. The cross section with respect to the longitudinal direction of the fiber to be exposed is exposed. Thereby, on the surface of the sound absorption part which exposed the said cross section, it can be made to act also to attenuate a sound between fibers, and a sound absorption effect can be improved more.

  The sound absorber body 2 in the sound absorber 1 of the present invention is preferably a laminate including a honeycomb structure in a part of the laminate as in the example shown in FIG. The honeycomb structure 5 is not particularly limited as long as it is a structure having a space by a cell structure. Usually, a plurality of or a plurality of continuous flaky or narrow sheets are used to form a plurality of independent cells in a mesh or lattice shape. It is a plate-like (or sheet-like) structure formed in the above.

  As a material for the honeycomb structure, a material having a small specific gravity, for example, papers, synthetic resins, lightweight metal materials, ceramics, and the like can be used from the viewpoint of weight reduction. Of these materials, paper is preferable because it is lightweight and inexpensive. As the paper, for example, cardboard base paper, paperboard board, printing / information paper, and the like can be used. When flame retardancy is required, paper that has been flame-treated by impregnation with aluminum hydroxide or the like, or paper on which a metal foil such as aluminum is laminated are particularly suitable.

  The thickness of the flaky sheet constituting the honeycomb structure is, for example, 0.01 to 5 mm, preferably 0.02 to 10%, from the viewpoint of securing lightness and a large space in the cell and ensuring strength as a structural panel. The thickness is 3 mm, more preferably 0.03 to 2 mm, and particularly preferably 0.05 to 1.5 mm.

  The shape of the cells forming the honeycomb structure is not limited to a so-called honeycomb shape (hexagonal shape), but a triangular shape, a lattice shape (square shape such as a square shape, a rectangular shape, a rhombus shape, and a parallelogram shape), a pentagon shape, and a circle shape It may be a shape, an elliptical shape, a wave shape, or the like. The corrugated shape is a shape in which the corrugated sheet is in contact with or adhered to the top of the flat sheet that is parallel to each other (the shape in which the flat sheet and the corrugated sheet are alternately laminated), or the flat sheet that is parallel to each other. A shape in which a plurality of corrugated sheets are in contact with or adhered to each other at the top may be used. Further, these shapes may be formed by folding a continuous sheet.

  The average diameter of each cell is, for example, from 1 to 100 mm, preferably from 3 to 80 mm, more preferably from 5 to 60 mm, and particularly preferably from 10 to 50 mm, from the viewpoint of balance between sound absorption range, sound absorption, strength, and the like. For example, a general-purpose size such as a cell diameter of 5 mm, 10 mm, 20 mm, or 30 mm can be used depending on the application. In addition, the average diameter of the cell in this invention is calculated according to a shape, and means the average value of the long diameter and short diameter in the case of an anisotropic shape. Specifically, in the case of a regular hexagon, the shortest distance between opposite sides is the average diameter, in the case of a square, the length of each side is the average diameter as it is, and in the case of a rectangle, the length between the long side and the short side is The average value is the average diameter. In the case of a waveform, the average value of the height of the top and the length of the bottom of the wave is the average diameter.

  The thickness (cell height) of the honeycomb structure is sufficient if sound absorption can be ensured. From the viewpoint of sound absorption, a larger thickness is preferable. For example, the average thickness may be 5 mm or more. Furthermore, the average thickness of the honeycomb structure is, for example, 5 to 50 mm, preferably 8 to 40 mm, more preferably 10 to 30 mm, and particularly preferably 15 to 25 mm, from the viewpoint of the balance between sound absorption, handling, and workability. is there. If the thickness of the honeycomb structure is too small, the sound absorbing property is lowered and the rigidity may be lowered. On the other hand, when the thickness of the honeycomb structure is too large, the handleability and workability may be deteriorated.

  Of course, commercially available honeycomb structures may be used. Specific examples of commercially available honeycomb structures include “New Die Score”, “E-stage core series”, “Honeycomb core series”, “Aluminum hydroxide core”, “NB core”, etc., manufactured by Nagoya Core Industry Co., Ltd. Can be mentioned.

  Further, when the sound absorber main body 2 in the present invention includes a laminated structure (not limited to a configuration in which the honeycomb structure is included in a part of the laminate), in the portion of the sound absorber main body that is not covered with the reflector, It is preferable that the cross section is exposed. For example, in the example shown in FIG. 1, it is comprised so that the cross section of the laminated structure by the porous body pinched | interposed into the non-woven fiber structure may be exposed in the four side surfaces B. Thereby, various sound absorbing structures can be exposed in the sound absorbing portion, and the sound absorbing effect can be further enhanced.

  FIG. 3 is a diagram schematically showing a sound absorber 11 according to a preferred second example of the present invention. The sound absorber 11 of the example shown in FIG. 3 is the same as the sound absorber 1 of the example shown in FIG. 1 except for a part, and the same parts are denoted by the same reference numerals and description thereof is omitted. In the example shown in FIG. 3, in addition to the reflectors 3 that respectively cover the two main surfaces A (A1, A2) of the plate-like sound absorber body, a reflector 12 that covers a part of the side surface B is further provided. Thus, in addition to at least one of the main surfaces A, a part of the side surface B may be covered with the reflector 12. The preferable material and thickness of the reflector 12 are the same as those described above for the reflector 3.

  FIG. 4 is a diagram schematically showing a sound absorber 21 of a third preferred example of the present invention. The sound absorber 21 of the example shown in FIG. 4 is the same as the sound absorber of the example shown in FIG. 1 except for a part thereof, and the same reference numerals are given to the same parts and the description thereof is omitted. In the sound absorbing body 21 of the example shown in FIG. 4, the sound absorbing body main body 22 is configured by a laminated body of three layers of nonwoven fiber structures 4. Of course, the sound absorber main body 22 may be composed of only the non-woven fiber structure.

  FIG. 5 is a view schematically showing a sound absorber 31 of a fourth preferred example of the present invention. The sound absorber 31 of the example shown in FIG. 5 is the same as the sound absorber of the example shown in FIG. 1 except for a part thereof, and the same parts are denoted by the same reference numerals and description thereof is omitted. In the sound absorber 31 of the example shown in FIG. 5, the sound absorber main body 32 is configured by a laminated body of three layers of porous bodies. As the porous body, for example, a corrugated cardboard is preferably used as the honeycomb structure 33. Thus, it goes without saying that the sound absorbing body main body 32 may be composed of only a porous body. In addition, in the example shown in FIG. 5, in addition to the reflector 3 that covers the two main surfaces A1 and A2 of the plate-like sound absorber main body 32, the reflector 34 that covers a part of the side surface B (for easy understanding of the structure). In FIG. 5, an end portion of the reflector 34 arranged on the front side is cut out).

  FIG. 6 is a diagram schematically showing a sound absorber 41 of a preferred fifth example of the present invention. The sound absorber 41 of the example shown in FIG. 6 is the same as the sound absorber of the example shown in FIG. 1 except for a part, and the same parts are denoted by the same reference numerals and description thereof is omitted. In the example shown in FIG. 6, the sound absorbing body main body 42 is configured by a laminated body of two layers of porous bodies. As the porous body, for example, cardboard is preferably used as the honeycomb structure 43.

  FIG. 7 is a view schematically showing a sound absorbing body 51 of a preferred sixth example of the present invention. The sound absorbing body 51 of the example shown in FIG. 7 is the same as the sound absorbing body of the example shown in FIG. 1 except for a part, and the same parts are denoted by the same reference numerals and description thereof is omitted. In the example shown in FIG. 7, only one main surface A <b> 1 is covered with the reflector 3 among the two main surfaces A (A <b> 1, A <b> 2) of the flat plate-like sound absorber body. As described above, in the present invention, as in the example shown in FIG. 1, the area of the sound absorber body 2 that is not covered with the reflector 3 is larger than the area of the portion covered with the reflector. However, as in the example shown in FIG. 7, the area of the sound absorber body 2 that is not covered with the reflector 3 may be larger than the area of the portion covered with the reflector. It is not excluded and is encompassed by the present invention.

  FIG. 8 is a diagram schematically showing a preferable installation example of the sound absorber of the present invention. In the example shown in FIG. 8, the sound absorber 61 has a sound absorbing portion 62 (that is, a surface not covered with the reflector 63) on the upper side and a height position near the ceiling 65 (a space for sound absorption is defined as a sound absorbing portion). Provided between the ceiling and the ceiling). As described above, in the present invention, since at least one of the main surfaces of the sound absorber main body having a relatively large area is used as the sound absorbing portion, the installation method has a higher degree of freedom than when the conventional main surface is used as the sound absorbing portion. high. By providing the sound absorbing body 61 as in the example shown in FIG. 8, the sound absorbing portion 62 can be made difficult to see by directing the sound absorbing portion 62 toward the ceiling, and finishing of the sound absorbing portion can be omitted. In addition, there is an effect that the sound absorber can be installed in a place where it does not interfere with life.

  FIG. 9 is a diagram schematically illustrating a preferable installation example of the sound absorber according to the present invention. In the example shown in FIG. 9, the sound absorber 61 is fixed to the wall 64 so that the sound absorbing portion 62 is on the lower side and the opposite side of the sound absorbing portion 62 is adjacent to the ceiling 65. As described above, the sound absorber 61 is provided adjacent to the ceiling 65, and the sound absorbing portion 62 is disposed on the lower side, so that it is possible to prevent the sound absorbing performance from being deteriorated over time due to the accumulation of dust in the sound absorbing portion 62. it can.

  FIG. 10 is a diagram schematically showing a preferred installation example of the sound absorber of the present invention. In the example shown in FIG. 10, the sound absorber 61 is fixed to the wall 64 at a height position near the floor 66 (a space for sound absorption is provided between the sound absorber and the floor) with the sound absorber 62 on the lower side. Yes. By doing in this way, the sound absorption part 62 can be made difficult to see similarly to the example shown in FIG. Further, dust can be prevented from accumulating in the sound absorbing portion.

  FIG. 11 is a diagram schematically illustrating a preferable installation example of the sound absorber according to the present invention. In the example shown in FIG. 11, the sound absorber 61 is fixed to the wall 64 so that the sound absorbing portion 62 is on the upper side and the opposite side of the sound absorbing portion 62 is adjacent to the floor 66. Thus, by providing the sound absorber 61 so as to be adjacent to the floor 66 and setting the sound absorber 62 on the upper side, there is an advantage that the space can be used effectively. In addition, as shown in FIG. 11, when installing the sound absorption body 61, it is preferable to cover the sound absorption part 62 with cloth.

  The present invention also provides a sound absorption method using the above-described sound absorber of the present invention. That is, the sound absorbing method of the present invention includes a sound absorber main body having at least one main surface and a reflector covering at least one of the main surfaces, and the sound absorber main body is not covered with the reflector. The sound absorbing body having the above is used, and the sound is absorbed only by the portion.

<Example 1>
A sound absorber 1 having the structure shown in FIG. 1 was prepared. Specifically, two plywoods of 600 mm × 900 mm and a thickness of 9 mm (Sina plywood, manufactured by Bill Crane Veneer Co., Ltd.) are used as the reflector 3, and one honeycomb structure 5 having the same area as the reflector and a thickness of 20 mm is used. Paper honeycomb (NB NKN, manufactured by Nagoya Core Industry Co., Ltd.) was used.

  As the non-woven fiber structure 4, a non-woven fiber structure having the same area as the reflector and having a thickness of 5 mm was produced by the following procedure.

  As a wet heat adhesive fiber, a core-sheath type composite staple fiber in which the core component is polyethylene terephthalate and the sheath component is an ethylene-vinyl alcohol copolymer (ethylene content: 44 mol%, saponification degree: 98.4 mol%) ( Sophista (manufactured by Kuraray Co., Ltd.), fineness: 3.3 dtex, fiber length: 51 mm, core-sheath mass ratio = 50/50, number of crimps: 21 pieces / 25 mm, crimp ratio: 13.5% were prepared.

Using this core-sheath type composite staple fiber, a card web having a basis weight of about 125 g / m ² was prepared by a card method, and four webs were stacked to form a card web having a total basis weight of about 500 g / m ² .

  The card web was transferred to a belt conveyor equipped with a 50 mesh, 500 mm wide stainless steel endless net. In addition, the belt conveyor which has the same metal mesh is equipped in the upper part of the metal mesh of this belt conveyor, and each used the belt conveyor which can adjust the space | interval of these metal meshes arbitrarily, rotating in the same direction at the same speed. .

  Next, the card web is introduced into a steam spraying device provided in the lower conveyor, and steam treatment is performed by ejecting high-temperature steam of 0.4 MPa from the device in the thickness direction of the card web (perpendicularly). As a result, a molded body having a non-woven fiber structure was obtained. In this steam spraying device, a nozzle is installed in the lower conveyor so as to spray high-temperature steam toward the web via a conveyor net, and a suction device is installed in the upper conveyor. Further, another jetting device, which is a combination of the arrangement of the nozzle and the suction device reversed, is installed on the downstream side in the web traveling direction of this jetting device, and steam treatment is performed on both the front and back sides of the web. did.

  In addition, the hole diameter of the water vapor | steam injection nozzle was 0.3 mm, and the vapor | steam injection apparatus with which the nozzle was arranged in 1 row at 1 mm pitch along the width direction of the conveyor was used. The processing speed is 3 m / min, and the interval (distance) between the upper and lower conveyor belts on the nozzle side and the suction side is a non-woven fiber structure having a thickness (measured in accordance with JIS L1913 “General Short Fiber Nonwoven Fabric Test Method”) of 5 mm. It was adjusted so that the body was obtained. The nozzles were arranged on the back side of the conveyor belt so as to be almost in contact with the belt.

The obtained non-woven fiber structure (molded body) had a board-like form and was very hard as compared with a general nonwoven fabric. It was calculated from the above thickness measured according to JIS L1913 “General Short Fiber Nonwoven Fabric Test Method” and the basis weight (500 g / cm ³ ) measured according to JIS L1913 “General Short Fiber Nonwoven Fabric Test Method”. The apparent density was 100 kg / m ³ . Further, the fiber adhesion rate was 15.1% on the front surface side, 12.0% on the center portion, and 14.0% on the back surface side.

  The fiber adhesion rate was calculated as follows. Using a scanning electron microscope (SEM), a photograph in which the cross section of the structure was magnified 100 times was taken. The photograph of the cross section in the thickness direction of the photographed structure is divided into three equal parts in the thickness direction, and the number of fiber cut surfaces (fiber end faces) that can be found in each of the three divided areas (front surface, inside (center), back surface) On the other hand, the ratio of the number of cut surfaces where the fibers are bonded to each other was determined. Of the total number of fiber cross-sections that can be found in each region, the ratio of the number of cross-sections in the state where two or more fibers are bonded is expressed as a percentage based on the following formula. In addition, in the part which fibers contact, there exists a part which is simply contacting, without melt | fusion, and a part which has adhere | attached by melt | fusion. However, by cutting the structure for microscopic photography, the fibers in contact with each other are separated from each other by the stress of each fiber on the cut surface of the structure. Therefore, in the cross-sectional photograph, it can be determined that the contacting fibers are bonded to each other.

Fiber adhesion rate (%) = (number of cross sections of fibers bonded two or more) / (number of total fiber cross sections) × 100
However, for each photograph, all the fibers with a visible cross section were counted, and when the number of fiber cross sections was 100 or less, a photograph to be observed was added so that the total fiber cross section exceeded 100. In addition, the fiber adhesion rate was calculated | required about each area | region divided into three equally, and the ratio (minimum value / maximum value) of the minimum value with respect to the maximum value was also calculated | required together. This nonwoven fiber structure was cut into a size of 600 mm × 900 mm (thickness: 5 mm).

  A honeycomb structure is sandwiched between two nonwoven fiber structures to create a laminated structure of a porous body, which is used as a sound absorber body, and two main surfaces thereof are covered with a reflector, as shown in FIG. The sound absorber 1 of the present invention was created. The total thickness of the sound absorber was 48 mm (reflector (9 mm) / nonwoven fiber structure (5 mm) / honeycomb structure (20 mm) / nonwoven fiber structure (5 mm) / reflector (9 mm)).

  FIG. 12 is a diagram schematically illustrating the arrangement of the sound absorber when evaluating the sound absorbing performance of the sound absorber in the first embodiment. FIG. 13 is a diagram schematically illustrating an example of equipment for evaluating the sound absorbing performance of the sound absorber. In Example 1, two created sound absorbers were separated so that the longitudinal distance Y of 900 mm was parallel so that the linear distance Z along the width direction X of 600 mm was 600 mm. The width of the sound absorbing body) +600 mm (linear distance Z) +600 mm (width of the sound absorbing body) was set to be 1800 mm in total. The sound absorption performance was evaluated in a pentagonal closed room as shown in FIG. 13 by the reverberation room method based on the standard of JIS A 1409. In FIG. 13, “s” indicates a sound absorber arranged as shown in FIG. 12, and a reverberation room method sound absorption coefficient is measured using an acoustic measurement system (“PULSE 3560” manufactured by Brüel & Kjær). It was measured.

<Example 2>
FIG. 14 is a diagram schematically illustrating the arrangement of the sound absorbers in the evaluation of the sound absorbing performance of the sound absorber in the second embodiment. In Example 2, four sound absorbers that are the same as Example 1 except that the length along the width direction X is set to 300 mm, as shown in FIG. 14, the longitudinal direction Y of 900 mm is parallel. , 300 mm (sound absorber width) +300 mm (straight distance Z) +300 mm (sound absorber width) +300 mm (straight distance Z) as a whole, separated so that the linear distance Z along the width direction X of 300 mm is 300 mm. +300 mm (width of the sound absorber) +300 mm (straight distance Z) +300 mm (width of the sound absorber) was set to be 2100 mm in total. Other than that was carried out similarly to Example 1, evaluated the sound absorption performance, and calculated the sound absorption rate in each frequency.

<Example 3>
The sound absorber 11 of the example shown in FIG. 3 was produced. Covering the entire surface of one of the four side surfaces of the sound absorber 1 produced in Example 2 (length along the width direction X: 300 mm, length along the longitudinal direction Y: 900 mm, thickness: 48 mm), A 900 mm × 48 mm 9 mm-thick plywood (Sina plywood, manufactured by Bill Crane Veneer Co., Ltd.) was attached as the reflector 12. Otherwise, the sound absorption performance was evaluated in the same manner as in Example 2, and the sound absorption rate at each frequency was calculated.

<Example 4>
The sound absorber 51 of the example shown in FIG. 7 can be manufactured by, for example, not attaching one of the two reflectors of the sound absorber 1 having the size described in the second embodiment. In this case, the total thickness of the sound absorber is 39 mm (reflector (9 mm) / nonwoven fiber structure (5 mm) / honeycomb structure (20 mm) / nonwoven fiber structure (5 mm)). By installing such a sound absorbing body 51 so that the reflector is on the upper side, it is considered that the sound absorbing performance equivalent to that of Example 2 is exhibited.

<Comparative Example 1>
FIG. 15 is a diagram schematically illustrating the sound absorber 101 manufactured in Comparative Example 1. The sound absorber 101 shown in FIG. 15 is not included in the present invention, but is the same as the sound absorber of the example shown in FIG. 1 except for a part, and the same reference numerals are given to the same parts. Description is omitted. The sound absorber 101 manufactured in Comparative Example 1 is not provided with a reflector that covers the two main surfaces of the flat sound absorber body 2, and instead, four sheets whose four side surfaces are the reflectors 102. Plywood (Sina plywood, manufactured by Bill Crane Veneer Co., Ltd.) (900 mm x 30 mm, 9 mm thick 9 mm thick plywood and 318 mm x 30 mm, 9 mm thick plywood covered (for easy understanding of the structure, In Fig. 15, a part of the reflector 102 is cut away.) That is, this corresponds to the case where the main surface of a conventional flat plate-like sound absorber body is used as the sound absorber. Except for the use, the sound absorption performance was evaluated in the same manner as in Example 2, and the sound absorption rate at each frequency was calculated.

<Comparative example 2>
FIG. 16 is a diagram schematically illustrating the sound absorber 111 manufactured in Comparative Example 2. The sound absorber 111 shown in FIG. 16 is not included in the present invention (the sound absorber body does not have a portion not covered with a reflector), but the sound absorber of the example shown in FIG. The same parts are denoted by the same reference numerals, and the description thereof is omitted. In FIG. 16, the entire surface of the four side surfaces of the sound absorber shown in FIG. 7 (that is, the configuration in which only one side (upper side) of the two main surfaces of the plate-like sound absorber body is covered with the reflector) is the reflector. 112 plywood (Sina plywood, manufactured by Sasazuru Beniya Co., Ltd.) 112 (covered with two 9 mm thick 900 mm × 39 mm plywood and two 9 ply 318 mm × 39 mm thick plywood (structure For the sake of clarity, a part of the reflector 112 is cut out in Fig. 16. That is, this corresponds to the case where the main surface of a conventional flat plate-like sound absorber body is used for the sound absorbing portion. Except for using such a sound absorber, the sound absorption performance was evaluated in the same manner as in Example 2, and the sound absorption rate at each frequency was calculated.

  FIG. 17 is a graph showing the evaluation results for Examples 1 to 3 and Comparative Examples 1 and 2, where the vertical axis represents the sound absorption coefficient and the horizontal axis represents the frequency (Hz). In addition, Table 1 shows numerical values for Examples 1 to 3 and Comparative Examples 1 and 2. From FIG. 17, it can be seen that Examples 1 to 3 showed sufficient sound absorbing performance even in a low frequency region of 1000 Hz or less, as compared with Comparative Examples 1 and 2.

  DESCRIPTION OF SYMBOLS 1 Sound absorber, 2 Sound absorber body, 3 Reflector, 4 Non-woven fiber structure, 5 Honeycomb structure, A, A1, A2 Main surface, B side surface, 11 Sound absorber, 12 Reflector, 21 Sound absorber, 22 Sound absorption Body body, 31 Sound absorber, 32 Sound absorber body, 33 Honeycomb structure, 34 Reflector, 41 Sound absorber, 42 Sound absorber body, 43 Honeycomb structure, 51 Sound absorber, 61 Sound absorber, 62 Sound absorber, 63 Reflector , 64 walls, 65 ceiling, 66 floor, s sample, 101 sound absorber, 102 reflector, 111 sound absorber, 112 reflector.

Claims (7)

Comprising a flat sound absorber body comprising two major surfaces, and a reflector that covers both of the two major surfaces, a sound absorbing member having a portion where the sound absorbing body is not covered with said reflector And
The area of the portion not covered with the reflector of the sound absorber body is smaller than the area of the portion covered with the reflector,
The sound absorber body, Ri laminate der comprising a honeycomb structure in a part of the laminate,
In the portion of the sound absorber body that is not covered with the reflector, the cross section of the laminated structure is exposed, so that the sound absorption structure is exposed in the portion of the sound absorber body that is not covered with the reflector. , Sound absorber. The sound absorber according to claim 1, wherein the sound absorber body includes a porous body . The sound absorber according to claim 1 or 2, wherein the sound absorber body includes a non-woven fiber structure . The sound absorber according to claim 3, wherein a cross section of the fiber constituting the nonwoven fiber structure with respect to a fiber longitudinal direction is exposed in a portion of the sound absorber body that is not covered with the reflector . The sound-absorbing body according to claim 3 or 4, wherein the non-woven fiber structure includes wet heat adhesive fibers . The sound-absorbing body according to claim 5, wherein the fibers are fixed at an adhesion rate of 1 to 85% by fusion of the wet heat adhesive fibers . A flat sound absorber body comprising two major surfaces, and a reflector that covers both of the two major surfaces, a sound absorbing member having a portion where the sound absorbing body is not covered with said reflector The area of the sound absorber body that is not covered with the reflector is smaller than the area of the part covered with the reflector, and the sound absorber body includes a honeycomb structure as a part of the laminate. Karadadea is, the in the portions not covered by the reflector of the sound absorbing body, that the cross section of the laminate structure is exposed, the sound absorbing structure in the portion not covered with the reflector of the sound absorber body A sound absorbing method in which a sound absorber is exposed and the sound is absorbed only by the portion.

Images