JP2005226361A - Rigid body sound absorbing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively provide a rigid body sound absorbing plate having superior sound absorbing performance, by using a recycling raw material, without requiring an expensive foaming agent and various additives, without requiring an expensive facility such as an autoclave curing and backing process. <P>SOLUTION: This sound absorbing plate is constituted by binding mutual granules 1 in its contact part by an aggregate of the granules 1 composed of polyurethane powder 3 and an inorganic binder 2 for binding the polyurethane powder 3, or is constituted with the polyurethane powder, short fiber and the inorganic binder as a main element, or is also constituted by combining and laminating both. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rigid sound-absorbing plate that has excellent sound-absorbing performance and is lightweight and inexpensive.

  Rigid sound absorbing plates are widely used for sound absorption of sound barriers for roads and railways, railway track surfaces, silencers, inner and outer walls of buildings, floors, and ceilings. The main sound absorbing action of the rigid sound absorbing plate is as follows. That is, an incident sound wave, that is, air vibrations propagates in a large number of continuous pores of the sound absorbing plate, and viscous friction of air is generated in the vicinity of the walls of the pores to attenuate the air vibrations, thereby absorbing sound.

  The rigid sound-absorbing plate that exhibits the sound-absorbing action described above is classified into a particle-coupled sound-absorbing plate and a foam-type sound-absorbing plate depending on the manufacturing method.

  The particle-bonded sound absorbing plate is formed by, for example, adding a molding binder and a sintered binder to ceramic particles and mixing them, forming the resulting mixture into a plate shape, drying or degreasing the mixture, and then about 1300 ° C. It is manufactured by sintering with, and is widely used practically.

  In recent years, many proposals have been made on inexpensive rigid sound-absorbing plates using raw materials such as waste. As a particle-bonded sound-absorbing plate, for example, waste foamed polystyrene is heat-cured and then pulverized to obtain lightweight fine aggregates. A method for obtaining a lightweight sound absorbing plate having an open porosity of 28 to 35% has been proposed by bonding and curing the obtained lightweight fine aggregate with a cement paste (see, for example, Patent Document 1). .

JP 2001-163684 A

  It has also been proposed to use foam glass as the above-mentioned lightweight fine aggregate. That is, a lightweight fine aggregate made of foamed glass by pulverizing waste glass, adding a foaming agent to the pulverized waste glass, kneading and granulating, firing the obtained granulated product, and foaming in the firing process Then, this lightweight fine aggregate is combined with an inorganic binder to form a sound absorbing plate (see, for example, Patent Document 2).

JP 2001-220262 A

  Furthermore, a method has been proposed in which a lightweight fine aggregate made of foamed glass prepared as described above is combined with cement to form a sound absorbing plate (for example, see Patent Document 3).

JP 2002-326880 A

  On the other hand, the foam-type sound absorbing plate is manufactured as follows. For example, water, a water reducing agent, a setting retarding agent, a strength development accelerator, a hydraulic substance, and a hydration reaction accelerator are kneaded to form a cement slurry, and bubbles are mixed into the cement slurry. A foam slurry is prepared. Next, a rapid base hydraulic substance and water are mixed with the air bubble slurry to form a porous base material slurry. The base material slurry is placed in a mold and steam-cured at room temperature and normal pressure. To cure. Thus, a foam-type sound absorbing plate made of a porous open-cell concrete compact is obtained (see, for example, Patent Document 4).

Japanese Patent Application Laid-Open No. 07-165477

  A method of performing autoclave curing using a relatively inexpensive foaming agent has also been proposed for the foam type sound absorbing plate. For example, a foam solidified body composed of latent hydraulic particles and tobermorite produced in the manufacturing process is used as a sound absorbing material. Coal ash, blast furnace slag, etc. are used as latent hydraulic particles. A foamed sound absorbing plate can be obtained by adding metal aluminium as described above and performing autoclave curing (see, for example, Patent Document 5).

Japanese Patent Laid-Open No. 08-283078

  A method for combining foaming and firing has been proposed for various types of waste. This method is to obtain a porous body of independent pores by foaming in a mold form from a slurry-like preparation by the action of a metallic aluminum foaming agent, and then to make a continuous pore structure by volume expansion of the composition in the firing step. is there. Recycled raw materials such as blast furnace slag, cast slag, municipal waste slag, waste glass, fly ash, etc. are used as raw materials, in addition to hydraulic cement, heat-foamable shale, pearlite, obsidian, etc. (For example, refer to Patent Document 6).

Japanese Patent Laid-Open No. 10-182262

  In addition, fly ash and cement are mixed, water is added, and foaming is performed by supplying air from the lower surface. The resulting molded product is subjected to autoclave curing at a temperature of 100 ° C. or higher to obtain a molded product. A method has also been proposed (see, for example, Patent Document 7).

JP 2001-342053 A

  Furthermore, a lightweight mortar sound absorbing material formed by foaming a cement slurry in which a porous material such as a foamed polyurethane chip or short fiber, a foaming agent, cement, and water are mixed has been proposed. According to this method, by mixing porous materials, it is said that the open cells obtained by foaming of cement become a complicated route, resulting in improved sound absorption performance. As foamed polyurethane chips, soft polyurethane, hard polyurethane A material obtained by chipping semi-rigid polyurethane with a pulverizer or the like is used, and various types of waste foamed polyurethane chips can be used (for example, see Patent Document 8).

Japanese Patent Application Laid-Open No. 08-030275

  In the case of a particle-bonded sound absorbing plate, generally, a step of firing a molded plate obtained by adding and mixing a binder to ceramic particles at a high temperature is necessary. Therefore, there is a problem that the product becomes expensive as a result of requiring a large amount of energy for high-temperature baking.

  When using waste foamed polystyrene as a raw material for fine aggregate as disclosed in Patent Document 1, a process of heat-curing waste foamed polystyrene is required, and disclosed in Patent Documents 2 and 3. In the case of using foamed glass as a raw material for fine aggregates, waste glass must be pulverized and fired, and in the case of the method disclosed in Patent Document 2, the foamed glass A baking process is required. Therefore, due to these treatment steps, an increase in manufacturing cost cannot be avoided, and even if various wastes are used as starting materials, an inexpensive product cannot be obtained.

  In the case of the foam type sound absorbing plate, as disclosed in Patent Document 4, various additives for imparting appropriate foaming characteristics to the cement slurry are necessary. Therefore, there is a problem that the product becomes expensive as a result of the additive occupying a major part of the manufacturing cost.

  Further, as disclosed in Patent Document 5, even if an inexpensive material such as coal ash or blast furnace slag is used as the latent hydraulic particle, metal aluminum is added as a foaming agent, and expensive high-pressure equipment is required. As a result of the need for autoclave curing, soaring manufacturing costs are inevitable.

  In the case of a method that uses both foaming and firing, as disclosed in Patent Document 6, even if various wastes are used as the raw material, a high-temperature firing step exceeding 1000 ° C. is required. This is expensive. In addition, in the case of the method disclosed in Patent Document 7, autoclave curing at a temperature of 100 ° C. or higher is required for the molded product, which also requires a large amount of cost.

  In the case of a method in which a foaming agent is added to a cement slurry and continuous pores are formed by foaming of the cement slurry as disclosed in Patent Document 8, an expensive foaming agent is required, so that the manufacturing cost increases. Invite.

  Among the foamed polyurethane chips used in this method, the soft polyurethane chip has continuous pores, so it is meaningful to apply this and take over the continuous pores in the sound absorbing plate. However, since the foamed polyurethane chip is immersed in the cement slurry in the manufacturing process, the continuous pores are completely blocked by the intrusion of the cement slurry. As a result, it becomes difficult to transfer the continuous pores of the soft polyurethane to the product, so that the contribution of the soft polyurethane chip to the sound absorbing performance is small.

  An object of the present invention is to solve the above-described problems of the prior art, and to provide a rigid sound-absorbing plate that has excellent sound-absorbing performance and is lightweight and inexpensive.

  The rigid sound-absorbing plate of the present invention according to claim 1 is an aggregate of granules having a polyurethane powder and an inorganic binder as constituent elements, and is characterized in that the granules are bonded at a contact site.

  The rigid sound-absorbing plate of the present invention according to claim 2 is the sound-absorbing plate according to claim 1, characterized in that the polyurethane powder constituting the granules is partially exposed.

  The rigid sound-absorbing plate of the present invention according to claim 3 is characterized in that polyurethane powder, short fibers, and an inorganic binder are the main constituent elements.

  The rigid sound-absorbing plate of the present invention according to claim 4 is an aggregate of granules comprising a polyurethane powder and an inorganic binder as constituent elements, and the single or plural first sound-absorbing layers in which the granules are bonded at a contact site. And a single or a plurality of second sound absorbing layers mainly composed of polyurethane powder, short fibers, and inorganic binder.

  The rigid sound-absorbing plate of the present invention according to claim 5 is mainly composed of a first sound-absorbing layer bonded with an aggregate of granules comprising polyurethane powder and an inorganic binder, polyurethane powder, short fibers, and an inorganic binder. It is characterized by comprising a second sound absorbing layer as an element, wherein the second sound absorbing layer is a core layer, and both surfaces of the core layer are covered with a surface layer made of the first sound absorbing layer.

  The rigid sound-absorbing plate of the present invention according to claim 6 is an aggregate of granules comprising a polyurethane powder and an inorganic binder as constituents, and a surface layer comprising a first sound-absorbing layer in which the granules are bonded together at a contact site; A core layer composed of a second sound-absorbing layer comprising polyurethane powder, short fibers, and an inorganic binder as main components is laminated, and all the side surfaces of the surface layer and the core layer thus laminated, and the back surface of the core layer, It is characterized by being covered with concrete.

  A rigid sound-absorbing plate according to a seventh aspect of the present invention is the sound-absorbing plate according to any one of the first to sixth aspects, wherein the polyurethane powder is obtained by subjecting a rigid polyurethane foam to a compression treatment and a pulverization treatment. It is characterized by being the obtained powder.

  A rigid sound-absorbing plate according to an eighth aspect of the present invention is the sound-absorbing plate according to any one of the first to seventh aspects, wherein the polyurethane powder has a particle size of 10 mm or less.

  The rigid sound-absorbing plate of the present invention according to claim 9 is the sound-absorbing plate according to any one of claims 1 to 8, wherein the main component of the inorganic binder is blast furnace slag fine powder and / or Portland cement. It is characterized by being.

  The rigid sound-absorbing plate of the present invention according to claim 10 is the sound-absorbing plate according to any one of claims 1 to 8, wherein the main component of the inorganic binder is blast furnace slag fine powder and / or Portland cement. It is characterized by being coal fly ash.

  The rigid sound-absorbing plate according to claim 11 is the sound-absorbing plate according to any one of claims 1 to 8, wherein the main component of the inorganic binder is blast furnace slag fine powder and / or Portland cement. It is characterized by coal fly ash and gypsum and / or slaked lime.

  A rigid sound-absorbing plate according to a twelfth aspect of the present invention is the sound-absorbing plate according to any one of the third to eleventh aspects, wherein the short fibers are glass fibers.

The rigid sound-absorbing plate of the present invention according to claim 13 is the sound-absorbing plate according to claim 12, wherein the glass fiber has a fiber diameter of 1 to 30 μm and a length of 0.1 to 30 mm, SiO ₂ , It is characterized by mainly containing Al ₂ O ₃ and CaO.

  A rigid sound-absorbing plate according to a fourteenth aspect of the present invention is the sound-absorbing plate according to any one of the first to thirteenth aspects, wherein the open porosity is 30 to 90%.

  The rigid sound-absorbing plate of the present invention is composed of an aggregate of granules having polyurethane powder and an inorganic binder as constituent elements, or is composed of polyurethane powder, short fibers and an inorganic binder as main constituent elements, or The above two are combined and laminated. Therefore, according to the sound-absorbing plate of the present invention, expensive equipment such as autoclave curing and baking treatment, processes that require operation costs are unnecessary, and expensive foaming agents and various additives are not required. Furthermore, since various recycled raw materials can be used, the product price is reduced, and the light weight and excellent performance with high sound absorption are exhibited.

  As a polyurethane powder that is a material of the sound absorbing plate of the present invention, a flexible polyurethane foam inherently has continuous pores. Therefore, a powder obtained by pulverizing this can be used naturally and is suitable as a sound absorbing material. As such a flexible polyurethane foam, waste such as a bed mattress and an automobile interior material is used.

  On the other hand, the rigid polyurethane foam has independent pores inside the material and is formed by foaming. Such independent pores are occupied by the hydrofluorocarbon or cyclopentane used as the foaming agent, and thus do not contribute to sound absorption. Accordingly, rigid polyurethane foam has been conventionally considered inappropriate as a sound absorbing material.

  When the present inventor performs compression treatment on such a hard polyurethane foam that has been considered unsuitable for a sound absorbing material, the enclosed gas breaks and moves the pore walls, and further pulverization treatment It was found that the hard polyurethane foam can be made into a polyurethane powder having continuous pores since the enclosed gas is diffused to the outside by applying. That is, rigid polyurethane foam can also be used as a suitable sound-absorbing material if it is subjected to the compression and pulverization processes described above. As such a rigid polyurethane foam, insulating material waste such as building materials, refrigerators, vending machines, showcases, and cold cars is used.

  Unlike the polyurethane powder obtained from the flexible polyurethane foam, the polyurethane powder having continuous pores obtained from the rigid polyurethane foam is less likely to proceed with the substitution of the air and water contained therein. Therefore, it is difficult for rainwater to permeate into the granules composed of such polyurethane powder, and the structure of the intergranular pathway is simple, so that water does not stay easily, and rainwater easily passes through the intergranular pathway. To be discharged. As described above, the sound absorbing plate using the hard polyurethane foam as the polyurethane powder has excellent drainage properties, and thus has an advantage that the sound absorbing performance is not lowered when it rains.

  The sound-absorbing plate of the present invention according to claim 1 is an aggregate of granules having the above-mentioned polyurethane powder and inorganic binder as constituent elements, wherein the granules are bonded at a contact site.

  Examples of the main component of the inorganic binder include hydration-reactive inorganic substances such as Portland cement, blast furnace cement, and fly ash cement. As such an inorganic binder, those obtained by adding various gypsum and / or slaked lime to blast furnace slag fine powder can be used, and those obtained by further mixing coal fly ash may be used. In addition, as the inorganic binder, coal fly ash to which various gypsum and / or slaked lime are added can be used, and further, a silica precursor such as sodium silicate or ethyl silicate hydrolyzate is added. But you can.

  Particularly, as the inorganic binder, a blast furnace slag fine powder and / or a binder mainly composed of Portland cement is suitable, and an inorganic binder composed of blast furnace slag fine powder, Portland cement and coal fly ash is more suitable. The reason is that firstly, the material is inexpensive, secondly, the final strength of the product is high, and thirdly, the hydration reaction is accelerated by steam curing and the practical strength is reached in a relatively short time. It is done. An appropriate amount of water is added to the inorganic binder to generate a hydration reaction, thereby exhibiting a binding force.

  If necessary, a small amount of an organic binder may be added to the inorganic binder. However, organic binders represented by rubber latex, polyvinyl alcohol, ethylene vinyl acetate, methyl cellulose, carboxymethyl cellulose and organic silicic acid compounds are generally expensive, and their application impairs the economical efficiency of the sound absorbing plate of the present invention. Accordingly, when an organic binder is added to the inorganic binder, it is preferably 10 parts by weight or less, more preferably 2 parts by weight or less, with respect to 100 parts by weight of the hydration reactive inorganic substance as the main component. .

  The sound-absorbing plate of the present invention according to claim 1, wherein the granule comprising the polyurethane powder and the inorganic binder as described above is a single particle obtained by attaching an inorganic binder to the surface of the polyurethane powder, or the single particle It is a particle obtained by coalescence growth of particles, and is a general term for a granular material in which polyurethane powder is bound by an inorganic binder or a polyurethane coarse particle coated with an inorganic binder. In either case, it is necessary that the polyurethane powder is partially exposed, and ventilation is possible through this exposed portion.

  Such granules need to be bonded at the contact site. That is, the bonding strength is exhibited by the crystal phase generated based on the hydration reaction at the contact site between the granules. Furthermore, aeration is possible through voids between the granules. As described above, sound waves propagate through two paths having different structures of the intragranular path and the intergranular path, and are attenuated, thereby producing a sound absorbing effect. This is a feature of the sound-absorbing plate according to the first aspect of the present invention.

  FIG. 1 is a partial cross-sectional schematic view showing an example of the sound-absorbing plate of the present invention comprising an aggregate of granules. As shown in FIG. 1, the granule 1 includes a polyurethane powder 3 and an inorganic binder 2 that binds the polyurethane powder 3. The polyurethane powder 3 contained in the granule 1 is partially exposed and can be ventilated through its continuous pores. The inorganic binder 2 may have air permeability as long as the adhesive strength can be maintained. The granules 1 constituting the aggregate are bonded and bonded to each other at the contact site, and have continuous pores between the granules 1. Therefore, ventilation is possible through the continuous pores. Such a sound absorbing plate made of an aggregate of granules has two ventilation paths, and therefore exhibits excellent sound absorbing performance in a wide frequency range from low to high.

  In addition, the strength of the sound-absorbing plate can be increased by increasing the contact area between the granules. If priority is given to the strength, the space between the granules can be reduced and the air flow can be made dependent on the intra-granular route. It is. FIG. 2 is a schematic partial cross-sectional view of such a sound absorbing plate. As shown in FIG. 2, the granule 1 composed of the polyurethane powder 3 and the inorganic binder 2 that binds the polyurethane powder 3 is adhered with almost no gap between them, and the air flow is within the granule 1. Depends on the route.

  The polyurethane powder has a particle size distribution, but the particle size is preferably 10 mm or less. When the particle diameter of the polyurethane powder exceeds 10 mm, sound waves are reflected at the largest granule portion, resulting in a decrease in sound absorption coefficient.

  The sound-absorbing plate of the present invention according to claim 3 includes the above-described polyurethane, short fibers, and inorganic binder as main components.

  As the short fibers, inorganic fibers such as glass fibers and carbon fibers, synthetic fibers such as polyester, polypropylene, polyethylene, nylon, and vinylon, or natural fibers such as wood wool, wool, cotton, and hemp can be used.

As for the glass fiber, those having a fiber diameter of 1 to 30 μm and a length of 0.1 to 30 mm and mainly composed of SiO ₂ , Al ₂ O ₃ and CaO are preferable. The glass fiber applicable to the present invention is not particularly limited in its production method, but a fiber obtained by subjecting a borosilicate glass melt or various molten slags to scattering and quenching is suitable, and if necessary, a pulverization treatment is performed. The fiber lengths may be aligned.

  By allowing the short fibers to coexist with the polyurethane powder, a part of the short fibers provides a void as a fiber mass, and a part of the short fiber penetrates the surface of the polyurethane powder to form a void. The inorganic binder blended with the polyurethane powder and the short fiber has a function of binding the polyurethane powder and the short fiber and fixing the void structure.

  It is preferable that the polyurethane powder, the short fibers, and the inorganic binder, which are the main components of the sound absorbing plate of the present invention described in claim 3, occupy 90 parts by weight or more of the total weight of the sound absorbing plate. In addition, in order to strengthen the function, it does not prevent mixing a small amount of auxiliary materials. The sound absorbing plate thus obtained is suitable for absorbing higher frequency sound than the sound absorbing plate according to claim 1.

  The sound-absorbing plate of the present invention according to claim 4 is a single unit in which the granules are bonded to each other at a contact site in an aggregate of granules composed of polyurethane powder and an inorganic binder, which is a component of the sound-absorbing plate according to claim 1. Or a plurality of sound-absorbing layers (hereinafter referred to as first sound-absorbing layers) and one or a plurality of sound-absorbing layers, which are the constituent elements of the sound-absorbing plate according to claim 3, mainly comprising polyurethane powder, short fibers, and an inorganic binder. (Hereinafter referred to as a second sound absorbing layer). By such a combination of the first sound absorbing layer and the second sound absorbing layer, the width of the frequency of sound absorption can be expanded.

  The combination of the first sound absorbing layer and the second sound absorbing layer described above may be, for example, laminated in the order of the first sound absorbing layer and the second sound absorbing layer from the sound wave incident side, or conversely, the sound wave incident. The second sound absorbing layer and the first sound absorbing layer may be laminated in this order from the side, or the number of laminated layers may be increased like the first sound absorbing layer, the second sound absorbing layer, the first sound absorbing layer, and the second sound absorbing layer. . Such a combination of the first sound absorbing layer and the second sound absorbing layer can be performed in various forms.

  According to a fifth aspect of the present invention, the sound absorbing plate of the present invention is configured such that the second sound absorbing layer is a core layer, and both surfaces of the core layer are covered with the first sound absorbing layer. Since the surface of the second sound absorbing layer as the core layer is protected by the first sound absorbing layer as the surface layer in this way, the porosity of the second sound absorbing layer can be increased beyond the embrittlement constraint. it can.

  FIG. 3 is a partial cross-sectional schematic view showing an example of the sound absorbing plate of the present invention in which both surfaces of the core layer 4 made of the second sound absorbing layer are covered with the surface layers 5a and 5b made of the first sound absorbing layer. Since the core layer 4 made of the second sound absorbing layer is obtained by mixing short glass fibers with polyurethane powder and being fixed with an inorganic binder, fine pores and high porosity are realized. Such a core layer 4 is effective in absorbing sound in a high frequency range, but is fragile because of its high porosity.

  On the other hand, the surface layers 5a and 5b made of the first sound absorbing layer are aggregates of air-permeable granules made of polyurethane powder and an inorganic binder, and the granules are bonded to each other by an inorganic binder at a contact portion, so that high strength is obtained. The fragile core layer 4 is reinforced to give rigidity. Furthermore, the relatively coarse pores of the surface layers 5a and 5b are effective in absorbing sound in the low frequency range. Therefore, the sound absorption in the high frequency range by the core layer 4 and the sound absorption in the low frequency range by the surface layers 5a and 5b overlap, and sound absorption in a wide frequency range becomes possible.

  FIG. 4 is a partial cross-sectional schematic view showing an example of the sound absorbing plate of the present invention according to claim 6. As shown in the drawing, in this sound absorbing plate, a surface layer 5 comprising the first sound absorbing layer in which the granules are combined at a contact site with an aggregate of granules comprising polyurethane powder and an inorganic binder, polyurethane powder and short The core layer 4 made of the second sound absorbing layer mainly composed of fibers and an inorganic binder is laminated, and all the side surfaces of the laminated surface layer 5 and the core layer 4 and the back surface of the core layer 4 are: Covered by a concrete layer 6. As a result, the sound wave incident from the surface layer 5 side and attenuated by the core layer 4 can be blocked by the concrete layer 6, and further, since the entire sound absorbing layer is protected by the concrete layer 6, sound absorption due to wind pressure or mechanical impact is achieved. Layer breakage can be prevented.

  The open porosity, which is a standard indicating the ratio of continuous pores, is preferably in the range of 30 to 90%. When the open porosity is less than 30%, the number of continuous pores is small, the propagation path of sound waves is insufficient, and the sound absorption performance is deteriorated. On the other hand, if the open porosity exceeds 90%, the sound wave propagation path becomes linear, resulting in a decrease in sound wave attenuation and a similar decrease in sound absorption performance.

As the above-mentioned inorganic binder, a composition obtained by adding gypsum and / or slaked lime 0 to 20 wt% to blast furnace slag and / or Portland cement 30 to 100 wt% and coal fly ash 0 to 70 wt% is suitable for strength development. As the blast furnace slag fine powder, those having a high specific surface area of 3000 m ² / g or more are preferable from the viewpoint of strength development. Coal fly ash does not solidify alone, and if the blending ratio is too high, strength is reduced. The gypsum may be any of anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum. Such gypsum and slaked lime promote the hydration reaction of fine blast furnace slag powder and coal fly ash. Moisture is indispensable for hydration reaction and granulation, and the required amount varies depending on conditions.

  If the composition of the above materials is properly selected, as a hydration reaction, a steam-containing gas at 50 to 100 ° C. is brought into contact with the granule aggregate at normal temperature, and this is heated and heated while generating condensation of vapor, By holding, high strength can be imparted to the granule aggregate in a short time. According to the atmospheric pressure steam curing with this condensation heat transfer, the granular aggregate reaches a strength level comparable to the strength after 2 weeks of natural curing in a required time of 5 to 10 hours, and by hydration reaction, acicular crystals As a result of developing at the contact part between the granules and between the granules and developing the binding force, it can be put to practical use.

  The cross section of the sound absorbing plate prepared as described above is macroscopically the polyurethane powder apparent volume (including pores included in the polyurethane) and the inorganic binder apparent volume (including pores included in the inorganic binder) constituting the granule and Although it is divided into intergranular voids, from the viewpoint of ensuring shape retention and sound absorption performance, the apparent volume ratio of polyurethane powder is 20 to 70 vol%, the apparent volume ratio of inorganic binder is 20 to 50 vol%, and the intergranular voidage is 0 to 70 vol%. preferable.

  The hard polyurethane insulation recovered from the waste refrigerator is supplied to a twin screw type crusher, and extruded from a hole with a diameter of 5 mm of the crusher, thereby adding shear and compression to the heat insulation material, and crushing the hard polyurethane, The encapsulated hydrofluorocarbon was released, thereby obtaining a polyurethane powder. Next, the polyurethane powder was sieved and the particle size was adjusted to 3.35 mm or less.

  In a mortar mixer, 37.0 parts by weight of blast furnace slag fine powder, 24.1 parts by weight of coal fly ash, 2.8 parts by weight of slaked lime, 1.6 parts by weight of anhydrous gypsum, 9.7 parts by weight of polyurethane powder and 24.8 parts of water A part by weight was added and mixed to obtain a wet product.

  Next, the wet body was divided into small amounts into a pan pelletizer, and rolling granulation and discharge were repeated to obtain granules having a diameter of 1 to 5 mm. The obtained granules were immediately put into a mold having a width of 480 mm, a depth of 323 mm, and a height of 70 mm arranged on a vibration table until the thickness reached 50 mm and leveled.

  In this way, the mold with the granules was shaken for 5 seconds, and then the mold was removed. As a result, with the above composition, compaction hardly occurred, and a granule aggregate having a width of 480 mm, a depth of 323 mm, and a height of 50 mm was obtained. Next, the obtained granule aggregate was transferred to a steam curing room, and heat-treated at a temperature of 90 ° C. for 9 hours in the steam curing room. As a result, a sound-absorbing plate molded article according to claim 1 of the present invention was obtained, which was an aggregate of granules composed of polyurethane powder and an inorganic binder, and the granules were bonded at the contact site. The obtained compact had a bulk density of 0.88 g / cc and an open porosity of 61.5%.

  A polyurethane powder having a particle size of 3.35 mm or less obtained in the same manner as in Example 1 was placed in a mortar mixer, 38.5 parts by weight of blast furnace slag fine powder, 23.5 parts by weight of coal fly ash, 2.7 parts by weight of slaked lime. Then, 1.8 parts by weight of anhydrous gypsum, 9.4 parts by weight of polyurethane powder and 24.2 parts by weight of water were added and mixed to obtain a wet product.

  The wet body obtained as described above was divided into small amounts into a pan pelletizer, and rolling granulation and discharge were repeated to obtain granules having a diameter of 1 to 5 mm. The obtained granules were immediately put into a mold having an internal size of 480 mm in width, 323 mm in depth, and 70 mm in height arranged on a vibration table until a thickness of 70 mm was reached.

  In this way, the mold with the granules was shaken for 5 seconds, and then the mold was removed. As a result, consolidation progressed with the above composition, and a granule aggregate having a width of 480 mm, a depth of 323 mm, and a height of 31.8 mm was obtained. Next, the obtained granule aggregate was transferred to a steam curing room, and heat-treated at a temperature of 90 ° C. for 9 hours in the steam curing room. As a result, a sound-absorbing plate molded article according to claim 1 of the present invention was obtained, which was an aggregate of granules composed of polyurethane powder and an inorganic binder, and the granules were bonded at the contact site. The obtained compact had a bulk density of 1.17 g / cc and an open porosity of 35.6%.

  By sieving the polyurethane powder obtained in the same manner as in Example 1, the particle size was adjusted to 2.0 mm or less. This polyurethane powder having a particle size of 2.0 mm or less is placed in a mortar mixer, 22.3 parts by weight of blast furnace slag fine powder, 4.0 parts by weight of slaked lime, 3.3 parts by weight of anhydrous gypsum, 16.5 parts by weight of polyurethane powder, glass 0.7 parts by weight of fibers (fiber diameter 9 μm, fiber length 1.0 mm) and 27.6 parts by weight of water were added and mixed to obtain a wet body.

  Next, the wet body was put into a mold having an internal dimension of 480 mm width × 323 mm depth × 70 mm height arranged on a vibration table until the thickness reached 42 mm and leveled.

  In this way, the mold with the granules was shaken for 5 seconds, and then the mold was removed. As a result, consolidation progressed with the above composition, and a granule aggregate having a width of 480 mm, a depth of 323 mm, and a height of 37.5 mm was obtained. Next, the obtained granule aggregate was transferred to a steam curing room, and heat-treated at a temperature of 90 ° C. for 9 hours in the steam curing room. As a result, a sound-absorbing plate molded article according to claim 3 having polyurethane powder, short fibers, and an inorganic binder as main constituent elements was obtained. The obtained compact had a bulk density of 0.72 g / cc and an open porosity of 55.3%.

  By sieving the polyurethane powder obtained in the same manner as in Example 1, the polyurethane powder A having a particle size of 2.0 mm or less and the polyurethane powder B having a particle size of 2 to 5.66 mm having two different particle size ranges were used. A polyurethane powder was obtained, thereby preparing a sound absorbing plate having two layers.

  First, in a mortar mixer, 24.4 parts by weight of coal fly ash, 24.4 parts by weight of blast furnace slag fine powder, 3.8 parts by weight of slaked lime, 15.8 parts by weight of polyurethane powder A, glass fiber (fiber diameter 9 μm, fiber length 1 0.080) 2.8 parts by weight and 28.9 parts by weight of water were added and mixed to prepare 3080 g of raw material A. Next, 42.6 parts by weight of blast furnace slag fine powder, 4.7 parts by weight of slaked lime, 23.6 parts by weight of polyurethane powder B and 29.0 parts by weight of water are put into a mortar mixer and mixed to obtain a granular raw material B. 940 g was prepared.

  The raw material B obtained as described above is put into a mold having an inner dimension of 480 mm in width, 323 mm in depth, and 70 mm in height arranged on a vibration table, and then the raw material A is put in. And then shaken for 5 seconds. The layer thickness was 45.0 mm. Next, this was transferred to a steam curing room, and after heat treatment at a temperature of 90 ° C. for 9 hours in the steam curing room, the mold was removed. As a result, it is an aggregate of granules composed of polyurethane powder and an inorganic binder, and comprises a coarse first sound-absorbing layer in which the granules are bonded together at a contact site, polyurethane powder, short fibers, and an inorganic binder. The molded plate molded body according to claim 4, which is composed of two layers including a fine-grained second sound absorbing layer. The obtained molded product had an average bulk density of 0.56 g / cc and an open porosity of 64.9%.

  A three-layer sound-absorbing plate was prepared in which both surfaces of the core layer composed of a fine-grain sound-absorbing layer were covered with a surface layer composed of a coarse-grain sound-absorbing layer. First, by sieving the polyurethane powder obtained in the same manner as in Example 1, the particle size ranges of the polyurethane powder A having a particle size of 2.0 mm or less and the polyurethane powder B having a particle size of 2 to 5.66 mm are different. Two types of polyurethane powder were obtained. In a mortar mixer, 23.4 parts by weight of coal fly ash, 19.6 parts by weight of blast furnace slag powder, 8.6 parts by weight of Portland cement, 0.4 part by weight of gypsum, 15.6 parts by weight of polyurethane powder A, glass fiber (fiber 3.8 parts by weight (diameter: 9 μm, fiber length: 1.0 mm) and 28.6 parts by weight of water were added and mixed to prepare 2350 g of raw material A.

  Subsequently, 33.4 parts by weight of blast furnace slag fine powder, 14.3 parts by weight of Portland cement, 23.4 parts by weight of polyurethane powder B, and 28.9 parts by weight of water are added to and mixed with a mortar mixer. 1320 g was prepared.

  Half the amount of 660 g of the raw material B obtained as described above was put into a mold having an internal size of width 480 mm × depth 323 mm × height 70 mm arranged on a vibration table and leveled.

  Subsequently, the entire amount of the raw material A was added and leveled, and further, the remaining amount of the raw material B was 660 g and leveled. After completing the introduction of the raw materials, the mold was vibrated for 5 seconds. The layer thickness obtained was 50.2 mm.

  Subsequently, this was moved to the steam curing room, and after heat-treating at a temperature of 65 ° C. for 12 hours in the steam curing room, the mold was removed. As a result, the core layer of the fine second sound-absorbing layer mainly comprising polyurethane powder, short fibers, and inorganic binder, and an aggregate of granules comprising polyurethane powder and inorganic binder disposed on both surfaces thereof And the sound-absorbing-plate molded object of this invention which consists of three layers of the surface layer of the coarse-grained 1st sound-absorbing layer in which this granule was couple | bonded at the contact part was obtained. The obtained molded article had an average bulk density of 0.46 g / cc and an open porosity of 71.1%.

  A disk having a diameter of 99 mm was cut out from the molded body of the present invention consisting of two layers of a coarse first sound-absorbing layer and a fine second sound-absorbing layer prepared according to Example 4, and this was cut into a test piece a. did. Further, the sound-absorbing plate molded body of the present invention comprising three layers, the core layer of the fine-grained second sound-absorbing layer and the surface layer of the coarse-grained first sound-absorbing layer arranged on both surfaces thereof, prepared according to Example 5. Similarly, a disk having a diameter of 99 mm was cut out and used as a test piece b.

  The normal incident sound absorption coefficient of the test piece a and the test piece b was measured. In addition, the test piece a made the coarse grain side the entrance surface. Table 1 shows the measurement results.

  As is clear from Table 1, the sound absorption coefficient of the test piece a and the test piece b of the sound absorbing plate molded body of the present invention can be adjusted at any frequency of 400 Hz, 700 Hz, and 1 kHz by adjusting the thickness of the back air layer. It was high at over 70%.

  A sound absorbing plate was prepared in which a surface layer composed of a coarse sound absorbing layer and a core layer composed of a fine sound absorbing layer were laminated, and the laminated surface layer and all side surfaces of the core layer and the back surface of the core layer were covered with concrete. First, 31.5 parts by weight of blast furnace slag fine powder, 13.5 parts by weight of Portland cement, 9.9 parts by weight of polyurethane powder having a particle size of 2.0 mm or less, and 45.0 parts by weight of water are put into a mortar mixer and mixed. Then, the obtained mixture was passed through a sieve having an opening of 2 mm to prepare a granular raw material A.

  Next, 21.1 parts by weight of blast furnace slag fine powder, 9.0 parts by weight of Portland cement, 18.0 parts by weight of polyurethane powder having a particle diameter of 2.0 mm or less, glass fiber having a diameter of 9 μm and a length of 10 mm were put into a mortar mixer. 5 parts by weight and 47.4 parts by weight of water were added and mixed to prepare raw material B. Furthermore, 29.8 parts by weight of blast furnace slag fine powder, 12.8 parts by weight of Portland cement, 33.5 parts by weight of granulated blast furnace slag having a particle size of 2.0 mm or less, and 16.3 parts by weight of water are added to a mortar mixer. And mixed to prepare paste-like raw material C.

  Into a mold having a width of 480 mm × depth of 313 mm × height of 90 mm disposed on the vibration table, 2020 g of the raw material A is charged and pressed to a thickness of 20 mm. Above, 5930 g of the raw material B was added and pressed to a thickness of 50 mm. Next, the above-mentioned formwork is pulled out, and a packed layer of 70 mm thick made of the pressed raw materials A and B is placed around another formwork having an internal dimension of width 500 mm × depth 330 mm × height 110 mm. A 10 mm gap was provided.

  Thus, after supplying the said paste-form raw material C in the said gap | interval in the another formwork in which the filled layer is arrange | positioned, and the space above the filled layer (raw material B), it gives a vibration to a vibration table and paste-like The raw material C was flowed to form a smooth surface over the entire outer periphery of the packed bed. The thickness of the pasty raw material C in the upper part of the packed bed (raw material B) was 20 mm. Subsequently, this was moved to a steam curing room, and after heat treatment at a temperature of 65 ° C. for 12 hours in the steam curing room, the mold was taken out and air-dried for another 5 days.

  As a result, an aggregate of granules composed of polyurethane powder and an inorganic binder, the surface layer of the first sound-absorbing layer in which the granules are bonded together at the contact site, polyurethane powder, short fibers, and inorganic binder, The sound-absorbing plate according to claim 6 of the present invention is obtained, wherein the two sound-absorbing layers comprising the core layer of the second sound-absorbing layer are covered with concrete on all side surfaces and the back surface. The dimension of the obtained sound absorbing plate was 500 mm × 330 mm × 69 mm.

It is a partial cross section schematic diagram which shows an example of this invention sound-absorbing board which consists of an aggregate | assembly of a granule. It is a partial cross section schematic diagram which shows the other example of this invention sound-absorbing board which consists of an aggregate | assembly of a granule. It is a partial cross section schematic diagram which shows an example of this invention sound-absorbing board with which both surfaces of the core layer which consists of a 2nd sound absorption layer were coat | covered with the surface layer which consists of a 1st sound absorption layer. It is a partial cross section schematic diagram which shows an example of this invention sound-absorbing board by which the 1st sound absorption layer and the 2nd sound absorption layer were laminated | stacked, and all the side surfaces and the back surface were coat | covered with concrete.

Explanation of symbols

1 Granule 2 Inorganic binder 3 Polyurethane powder
4 core layer 5 surface layer 5a surface layer 5b surface layer 6 concrete layer

Claims (14)

  A rigid sound-absorbing plate, characterized in that it is an aggregate of granules comprising a polyurethane powder and an inorganic binder as constituent elements, and the granules are bonded together at a contact site.   The rigid sound-absorbing plate according to claim 1, wherein the polyurethane powder constituting the granules is partially exposed.   A rigid sound-absorbing plate comprising polyurethane powder, short fibers, and an inorganic binder as main components.   An aggregate of granules having polyurethane powder and an inorganic binder as constituents, the main component being one or a plurality of first sound absorbing layers in which the granules are bonded to each other at a contact site, polyurethane powder, short fibers, and an inorganic binder. A rigid sound-absorbing plate, wherein one or a plurality of second sound-absorbing layers as constituent elements are laminated.   An aggregate of granules having polyurethane powder and an inorganic binder as constituent elements, the first sound-absorbing layer in which the granules are bonded together at the contact site, the polyurethane powder, short fibers, and an inorganic binder as main constituent elements 2. A rigid sound-absorbing plate comprising two sound-absorbing layers, wherein the second sound-absorbing layer is a core layer, and both surfaces of the core layer are covered with a surface layer comprising the first sound-absorbing layer.   An aggregate of granules having polyurethane powder and an inorganic binder as constituent elements, and a main layer comprising a surface layer composed of a first sound absorbing layer in which the granules are bonded to each other at a contact site, polyurethane powder, short fibers, and an inorganic binder And a core layer made of the second sound absorbing layer is laminated, and all the side surfaces of the surface layer and the core layer laminated in this manner and the back surface of the core layer are covered with concrete. Board.   The rigid sound-absorbing plate according to any one of claims 1 to 6, wherein the polyurethane powder is a powder obtained by subjecting a rigid polyurethane foam to compression treatment and pulverization treatment.   The rigid sound-absorbing plate according to any one of claims 1 to 7, wherein a particle diameter of the polyurethane powder is 10 mm or less.   The rigid sound-absorbing plate according to any one of claims 1 to 8, wherein a main component of the inorganic binder is blast furnace slag fine powder and / or Portland cement.   The rigid sound-absorbing plate according to any one of claims 1 to 8, wherein the main component of the inorganic binder is blast furnace slag fine powder and / or Portland cement and coal fly ash.   The rigid sound absorbing material according to any one of claims 1 to 8, wherein the main component of the inorganic binder is blast furnace slag fine powder and / or Portland cement, coal fly ash, gypsum and / or slaked lime. Board.   The rigid sound-absorbing plate according to any one of claims 3 to 11, wherein the short fibers are glass fibers. The rigid sound-absorbing material according to claim 12, wherein the glass fiber has a fiber diameter of 1 to 30 µm, a length of 0.1 to 30 mm, and contains SiO ₂ , Al ₂ O ₃ and CaO as main components. Board.   The rigid sound-absorbing plate according to any one of claims 1 to 13, wherein the sound-absorbing plate has an open porosity of 30 to 90%.

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