WO2001074624A1 - Sound absorbing structure of floor surface - Google Patents

Abstract

A sound absorbing structure of a floor surface capable of efficiently reducing noise propagating from a floor surface to an indoor of, for example, a car, a train, or an aircraft, characterized in that a sound absorbing composite body comprising a sound absorbing film and foaming sheets having a plurality of through-holes each of which is integrally laminated on both surfaces of the sound absorbing film is disposed between the floor surface and a carpet, and a sound absorbing layer is provided between the sound absorbing composite body and the carpet.

Description

 Itoda »Floor sound absorption structure

 The present invention relates to a floor sound absorbing structure that can efficiently reduce noise propagating from the floor of a car, a train, an aircraft, or the like into a room. Background art

 Conventionally, for example, as shown in Fig. 9, the floor surface of a car, train, or aircraft is provided with a felt layer 2 on the floor F, and a carpet lined with a sound insulation layer 3 on the upper surface of the felt layer 2. It consisted of laying three.

 The noise transmitted from the floor F was first absorbed by the felt layer 2, and the sound passing through the felt layer 2 was cut off by the sound insulation layer 13 on the back of the carpet 3.

 However, the conventional felt layer 2 as a sound absorbing layer on the floor F can absorb sound more effectively as its thickness is larger, but it is limited to 5.0 Ocm due to the limited space of the floor F, and it should be thicker than that. As a result, a sufficient sound absorbing effect could not be secured.

 On the other hand, the sound insulation layer 13 on the back of the carpet 3 improves the sound insulation performance as the weight increases, but the weight of the carpet 3 reduces the weight and fuel consumption of vehicles during the energy-saving era. However, the heavier the weight, the more difficult it is to handle, which may hinder transportation and laying work on the floor. Under these circumstances, the existing vehicle floor has not been adequately sound-absorbed.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a floor sound absorbing structure capable of efficiently reducing noise from a floor. Disclosure of the invention

 The floor sound absorbing structure of the present invention (hereinafter simply referred to as a sound absorbing structure) is a sound absorbing composite comprising a sound absorbing film and a foam sheet having a large number of through holes laminated and integrated on both sides of the sound absorbing film. And a sound absorbing layer provided between the sound absorbing composite and the carpet.

 As shown in FIG. 1, the sound absorbing structure includes a sound absorbing composite 10 disposed on the floor F, a sound absorbing layer 2 provided on the upper surface of the sound absorbing composite 10, and a car laid on the sound absorbing layer 2. 3 Unit 3

 As shown in FIGS. 2 and 3, the sound absorbing composite 10 includes a sound absorbing film 21 and a foam sheet 22. The sound absorbing film 21 is sandwiched between two foam sheets 21 and is pulled into the through hole 23 with a portion of the foam sheet 21 located at the through hole 23 being free. Then, the sound absorbing film 22 stretched in the through hole 23 vibrates due to the sound collision, and the vibration consumes the energy of the sound as frictional heat, thereby reducing the sound.

 The material and structure of the sound-absorbing film 22 having such an operation and effect are not particularly limited as long as it can vibrate in response to a sound collision. A film containing an active ingredient that increases the amount of moment can be used.

 Hereinafter, the sound absorbing film containing the active ingredient will be described. The inventor of the present invention has found that, in addition to the above-described sound absorption mechanism of generating frictional heat and consuming sound energy due to vibration, the following sound absorption mechanism also works for the sound absorbing film, and the two work together to reduce sound. To be done.

 That is, as shown in FIG. 6, when sound collides with the film # 1, vibration is generated. At this time, a displacement occurs in the dipole 12 existing inside the film 11. The displacement of the dipole 1 2 means that each dipole 1 2 in the film 11 rotates or the phase shifts:

It can be said that the arrangement state of the dipoles 12 inside the film 11 before the sound energy is applied as shown in FIG. 5 is in a stable state. However, as shown in Fig. 6, when energy is applied to the film by the impact of sound, it exists inside the film. When the dipoles 12 are displaced, each dipole 1 2 inside the film 11 is put in an unstable state, and each dipole 1 2 tries to return to the stable state shown in FIG. I do.

 At this time, energy is consumed. It is thought that sound absorption performance is generated through the displacement of the dipole inside the film and the energy consumption due to the dipole restoring action.

 When considering the mechanism of such energy consumption, it is understood that the amount of the dipole moment inside the film 11 as shown in FIGS. 4 and 5 greatly affects the sound absorption performance. According to the experiments by the present inventors, it was found that the larger the amount of the dipole moment in the film 11, the higher the sound absorbing performance of the film 11.

 The amount of dipole moment inside a film composed of a polymer material varies depending on the type of the polymer material. Even if the same polymer material is used for the film, the amount of dipole moment generated inside the film changes depending on the temperature and frequency of sound when sound is applied. The amount of dipole moment also depends on the magnitude of the sound energy applied to the film. For this reason, considering the temperature at which this sound absorbing composite is applied, the frequency of the sound applied at the time of application, the magnitude of the energy, etc., the polymer material with the largest dipole moment at that time is selected and used. Is desirable.

 Preferred polymer materials for the material of the sound absorbing film are, for example, polyvinyl chloride, polyethylene, chlorinated polyethylene, polypropylene, ethylene monoacetate copolymer, polymethyl methacrylate, polyvinylidene fluoride, polyisoprene, polystyrene, and styrene. 1-butadiene-acrylonitrile copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), butadiene rubber (BR), natural rubber (NR), Examples include isoprene rubber (IR).

In addition, when selecting the polymer material constituting the sound absorbing film, not only the amount of dipole moment inside the film but also the handleability, formability, availability, etc., depending on the application form of the sound absorbing structure. Temperature performance (heat resistance and cold resistance), weather resistance, price, etc. It is desirable to consider

 In this sound absorbing film, an active ingredient capable of dramatically increasing the amount of dipole moment inside the film is blended with a polymer material constituting the film. The active component is a component that dramatically increases the amount of dipole moment inside the film. The active component itself has a large dipole moment amount, or the active component itself has a small dipole moment amount. It means a component that can dramatically increase the amount of dipole moment inside the film by blending the active component.

 For example, the amount of the dipole moment generated inside the film 11 at a given temperature condition, sound frequency, and energy level is determined by mixing the active ingredient with the other, as shown in FIG. Under the same conditions, the amount will increase to three times and the force 力 0 times. Along with this, the energy consumption due to the dipole restoring action when the above-mentioned energy is added will also increase dramatically, resulting in excellent sound absorption performance far exceeding the prediction.

 Examples of active ingredients that induce such effects include N, N-dicyclohexylbenzothiazyl-2-sulfenamide (DCHB SA), 2-mercaptobenzothiazole (MBT), and dibenzothiazyl sulfide (MBTS). , N-cyclohexylbenzothiaziruyl 2-sulfenamide (CBS), N-tert-butyl benzothiazilyl 2-sulfenamide (BBS), N-oxyzettim Lembenozhiaziryl 2-sulfenamide (OBS), One or more compounds selected from compounds containing a benzothiazyl group, such as N, N-diisopropyl benzothiazyl-2-sulfenamide (DPBS);

Benzotriazole with an azole group bonded to the benzene ring as the mother nucleus, and a phenyl group bonded to the nucleus 2— {2′—Hydroxy 3 ′ — (3 ”, 4”, 5 ”, 6” Drophthalimidemethyl) — 5 '—Methylphenyl} 1-benzotriazole (2H PMMB), 2--12' —Hide mouth 5 '—Methylphenyl} —Benzotriazole (2HMPB), 2-I 2' One-high 3'-t-butyl-5'-methylphenyl} 1-5-chlorobenzototriazole (2HBMP CB), 2- {2'-hydroxide 3 ', 5'-g Butylphenyl I 5 One or more compounds selected from compounds having a benzotriazole group such as benzotriazole (2 HDBPCB)

 One or more compounds selected from compounds having a diphenyl acrylate group such as ethyl 2-cyano 3, 3-diphenyl acrylate;

 One type of compound is a compound having a benzophenone group, such as 2-hydroxyl 4-methoxybenzophenone (HMBP), 2-hydroxy-4-phenoxybenzophenone-5-sulfonic acid (HMBPS). One or more selected ones can be mentioned.

 The amount of the above-mentioned active ingredient is preferably from 10 to 300 parts by weight based on 100 parts by weight of the polymer material. For example, if the amount of the active ingredient is less than 10 parts by weight, the effect of increasing the amount of dipole moment by adding the active ingredient cannot be obtained, and the amount of the active ingredient is not more than 30 parts by weight. If it exceeds 0 parts by weight, it may not be sufficiently compatible.

 In deciding the active ingredient contained in the polymer material, it is good to select a substance having a similar value in consideration of the compatibility between the active ingredient and the polymer material, that is, the SP value.

 The amount of the dipole moment in the active ingredient varies depending on the type of the active ingredient, similarly to the amount of the dipole moment inside the film. Even when the same active ingredient is used, the amount of dipole moment generated inside the film changes depending on the temperature when sound energy is applied: Also, depending on the magnitude of the sound energy applied to the film, The amount of dipole moment changes. For this reason, it is desirable to select and use the active component having the largest amount of dipole moment in consideration of the magnitude of the temperature energy at the time of application.

 This sound absorbing film can be obtained by blending a polymer material and an active ingredient, and if necessary, a corrosion inhibitor and a dye, and forming the blend into a film. The polymer material and the active ingredient are blended, and the blend is formed into a film by a conventionally known molding method.

Next, the foam sheet 21 will be described. The foamed sheet 21 can withstand the external force applied during the production, handling, or use of the sound absorbing composite 10. It is preferable that the material has sufficient cushioning properties, as well as not being easily bent or damaged. Specifically, thermoplastic resins such as polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, ABS resin, polystyrene, and ethylene monoacetate copolymer, as well as sodium bicarbonate, ammonium bicarbonate, ammonium carbonate, and azide A foamed resin sheet having a closed-cell structure formed by adding a chemical foaming agent such as a compound and foaming is preferred. Among them, a foamed resin sheet using an ethylene-vinyl acetate copolymer is more preferable. The thickness of the foam sheet 21 is preferably from ◦ to 1.0 cm.

 Further, the foam sheet 21 has a large number of through holes 23. When sound passes through the through holes 23, the foam sheet 21 comes into contact with the walls of the through holes 23. At this time, the sound is absorbed as frictional heat. It has become. The type (frequency) of the sound absorbed when passing through the through hole 23 changes according to the diameter of the through hole 23. In addition, since the size of the portion of the sound absorbing film 23 extending in the through hole 23 changes according to the size of the diameter of the through hole 23, the type of sound absorbed by the sound absorbing film 21 (frequency ) Will also change.

 In the case of the foam sheet 2] of the present invention, the diameter of the through-holes 23 was in the range of 0.1 to 3 cm. This range of diameter of 0.1 to 3 cm specifies a range where sound can be effectively absorbed by the wall surface of the through hole 23 and the sound absorbing film 21, and the diameter of the through hole 23 is out of the range. In this case, it is difficult to absorb sound sufficiently. The type (frequency) of the sound to be absorbed also changes depending on the magnitude of the opening ratio of the through holes 23 of the foam sheet 21. In the case of the foam sheet 21 of the present invention, the opening ratio of the through-holes 23 was in the range of 1 to 80%.

As shown in FIG. 4, the through holes 23 of the foam sheets 21 a and 21 b are tapered in the thickness direction, and the sound absorbing film 22 is formed in the through holes 23. The hole diameter of the through holes 23a and 23b may be gradually reduced from one foam sheet 21a to the other foam sheet 2b. In this case, the sound propagating from the first direction, first impinges on one of the foam sheet 2 1 _a, while being reduced while colliding the Taber-shaped through-holes 2 3 a, penetrates into further sound absorbing composite 1 0 inner The sound absorbing complex 10 collides with the sound absorbing film 2 2 inside, and the sound absorbing film 2 2 After being reduced by the vibration of the other foamed sheet, the foamed sheet 21b passes through the tapered through hole 23b of a smaller diameter while being reduced while colliding. For this reason, sound is more efficiently reduced.

 In the embodiment shown in FIGS. 2 and 3, the foam sheet 21 is formed with three large, medium, and small circular through holes 23a, 23b, and 23c. The sound absorbing film 22 is sandwiched between 21 and laminated and integrated.

 In this case, the sound-absorbing film 22 has a portion positioned at the through-holes 23a, 23b, and 23c of the foam sheet 21 attached to the through-holes 23a, 23b, and 23c. It is set up and vibrates in a free state. Of these, the sound absorbing film 22 stretched over the large through hole 23a efficiently reduces low-frequency sound, and the sound absorbing film 22 stretched over the medium through hole 23b The sound in the frequency range of the sound range is reduced, and the sound absorbing film 22 stretched over the small holes 23c reduces the sound at high frequencies.

 By forming the through-holes 23 having different sizes in the foamed sheet 2 張 and stretching the sound-absorbing film 22 in each of the through-holes 23, one sound-absorbing composite 20 has a different frequency. Multiple sounds can be efficiently absorbed and reduced.

 The shape of the through-holes 23 of the foam sheet 21 can be freely selected such as 〇, △, mouth, etc., but among them, に く い is hardly formed when the sound absorbing film 22 is stretched. More preferred from that.

 In addition, by making the size and shape of each through hole 23 of the foam sheet 21 the same and appropriately changing the tensile strength of the sound absorbing film 22 stretched in the through hole 23, it is possible to cope with sounds having different frequencies. You can also. In other words, if the sound-absorbing film 22 is strongly stretched in the through-holes 23 of the foam sheet 21, high-frequency sound can be absorbed and reduced, and the sound-absorbing film 22 can be loosely inserted in the through-holes 23. If it is installed, it will be easier to pick up low-frequency sounds, and more effective sound reduction can be achieved.

The sound-absorbing composite uses a thin sound-absorbing film, a thick sound-absorbing film, and a film having a thickness between them. It is also possible to adopt a form in which the sheets are alternately arranged on a foam sheet and laminated and integrated. In this case, it is stretched between the through holes of the foam sheet. Sound-absorbing films with different thicknesses capture various sounds and vibrate to reduce them. In other words, a thin sound absorbing film captures and reduces high sounds, a thick sound absorbing film captures and reduces low sounds, and a sound absorbing film with an intermediate thickness between them reduces intermediate sounds. It is.

 In addition, other than the above, for example, a plurality of sound absorbing composites as shown in FIGS. 2 to 4 may be laminated.

 The above-described sound-absorbing complex 1 ◦ is arranged on the floor F, and a carpet 3 having a sound-insulating layer 13 on the back surface (side surface of the sound-absorbing layer 2) is laid on the sound-absorbing layer 2. It has been created.

 The sound-absorbing layer 2 is a layer made of a bulky fiber aggregate such as a felt / nonwoven fabric made of glass fiber, asbestos, plastic fiber, or the like. The sound insulation layer 13 on the back surface of the cartridge 3 is a layer formed by filling a polymer material such as a vinyl chloride resin and a acryl resin with an inorganic filler such as my flakes, talc, and calcium carbonate. .

 As shown in FIG. 1, when the sound absorbing composite 10, the sound absorbing layer 2, and the carpet 3 are arranged in this order on the vehicle floor F, there is a gap between the sound absorbing composite 10 and the sound insulating layer 13. The sound absorbing layer 2 made of a bulky fiber assembly is interposed, and when the sound passing through the sound absorbing composite 10 passes through the sound absorbing layer 2, it comes into contact with the fibers constituting the sound absorbing layer 2, and the energy of the sound Is consumed as frictional heat and the sound is reduced. Furthermore, the sound that has passed through the sound absorbing layer 2 is blocked by the sound insulating layer 13 on the back of the power socket 3.

At the same time the sound absorption layer 2 and the sound-absorbing composite 1 0 and force one ^ ^c, by providing between the Tsu bets 3, air between the backing film 2 1 and the sound insulation layer 1 3 of the sound-absorbing composite 1 0 A layer will be formed. The sound absorbing film 21 of the sound absorbing composite 10 has excellent sound absorbing performance as described above, but the type of sound to be absorbed is formed between the sound absorbing film 21 and the sound insulating layer 13. It varies greatly depending on the thickness of the air layer.

In other words, the higher the thickness of the air layer formed between the sound absorbing film 21 and the sound insulation layer 13, the lower the frequency of sound absorption, and the higher the thickness of the air layer, the higher the thickness. The sound of the frequency will be absorbed. Preferably, the thickness of the air layer, in other words, the thickness of the sound absorbing layer 2 is in the range of 0,5 to 5 cm. If the thickness of the air layer (sound absorbing layer 2) is less than 0.5 cm, it will effectively absorb extremely high, high-frequency sounds that cannot be perceived by humans. Does not make sense. On the other hand, if the thickness of the air layer (sound absorbing layer 2) exceeds 5 cm, low-frequency sound will be effectively absorbed, but the floor space will be reduced. Will be. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is an enlarged sectional view showing a sound absorbing structure of the present invention.

 FIG. 2 is an assembled perspective view showing the sound absorbing composite.

 Fig. 3 is an enlarged sectional view of the sound absorbing composite.

 FIG. 4 is an enlarged sectional view showing another example of the sound absorbing composite.

 Figure 5 is a schematic diagram showing the dipole inside the film.

 Figure 6 is a schematic diagram showing the state of the dipole inside the film when energy is applied.

 FIG. 7 is a schematic diagram showing a state of a dipole inside a film when an active ingredient is blended.

 FIG. 8 is an enlarged cross-sectional view showing a sound absorbing structure of a floor surface exemplified as a comparison.

 FIG. 9 is an enlarged sectional view showing a conventional sound absorbing structure for a vehicle floor.

FIG. 10 is a graph showing sound transmission loss evaluated for the sound absorbing structures shown in FIGS. 1, 8 and 9. Example

 Example

 Ethylene-vinyl acetate copolymer (Evaflex EV 260, manufactured by Mitsui Dupont Boli Chemical Co., Ltd.) and DCHBSA (Suncellar DZ-G, manufactured by Sanshin Kagaku Co., Ltd.) in a ratio of 80/20 The mixture was put into a kneading roll machine and kneaded, followed by heat breathing with a press machine to obtain a sound absorbing film (thickness: 0.2 mm;

On the other hand, a foaming agent was added to the ethylene-vinyl acetate copolymer and foamed at a magnification of 10 times. A molded foamed resin sheet having a thickness of 0.2 cm and having a closed cell structure was prepared. Next Ide, _c which was foam sheet to form a through-hole of 1 cm in diameter in the foamed resin sheet at intervals of 3 c mX 3 cm

 Next, foamed sheets were laminated on both sides of the obtained sound absorbing film, and each layer was integrated with an adhesive to obtain a sound absorbing composite.

Thereafter, as shown in FIG. 1, the obtained sound absorbing composite 10 was placed on the floor F, and a 0.8 cm thick felt layer (sound absorbing layer 2) was formed on the upper surface of the sound absorbing composite 10. The force absorption bed 3 provided with the sound insulation layer 13 on the back surface is laid on the felt layer (sound absorption layer 2). _C The transmission loss (at 63 Hz to 1 KHz) d B) was measured. The result is shown in Fig. 10 _c

 Comparative Example 1

 As shown in FIG. 8, except that the positions of the sound-absorbing composite 10 and the felt layer (sound-absorbing layer 2) were inverted, a sound-absorbing structure was formed in the same manner as in the example. The transmission loss (dB) at 11 KHz was measured. The results are shown in FIG.

 Comparative Example 2

 As shown in Fig. 9, a felt layer 3 is provided on the floor F, and a carpet 3 lined with a sound insulating layer 13 is laid on the felt layer (sound absorbing layer 2). The measurement of the transmission loss (dB) at KHz is shown in FIG.

 From FIG. 10, a comparative example 1 was used in which the sound absorbing composite 10 was used, placed on the floor via a felt layer (sound absorbing layer 2), and a carpet 3 was laid on the sound absorbing composite 10. In comparison with Comparative Example 2 which is a conventional floor structure, although there is a difference in height for each frequency, there is a large difference in the transmission loss dB as a whole. It was confirmed that there was not.

 However, although the same sound-absorbing composite 10 is used, a floor surface according to an embodiment in which a furt layer (sound-absorbing layer 2) (air layer) is provided between the sound-absorbing composite 10 and the carbette 3 is provided. In the structure, in the frequency range exceeding 750 Hz, the difference in transmission loss from the previous two cases was remarkable, and it was confirmed that the structure had excellent sound absorption performance.

Claims

Scope of word blue 1. A sound absorbing composite comprising a sound absorbing film and a foam sheet having a large number of through holes laminated and integrated on both sides of the sound absorbing film is disposed between a floor surface and a carpet; A sound-absorbing structure on the floor, characterized by providing a sound-absorbing layer between the body and the power unit.  2. The sound absorbing structure for a floor surface according to claim 1, wherein the sound absorbing film of the sound absorbing composite is a film in which an active ingredient for increasing a dipole moment is added to a polymer material.  3. The floor sound-absorbing structure according to claim 2, wherein the active ingredient is blended in an amount of 100 to 300 parts by weight with respect to 100 parts by weight of the film material.  4. The active ingredient is at least one compound selected from the group consisting of a compound having a benzothiazyl group, a compound having a benzotriazole group, a compound having a diphenylatylate group, and a compound having a benzophenone group. The floor sound absorbing structure according to claim 2 or 3, wherein:  5. The floor sound absorbing structure according to claim 1, wherein the thickness of the foam sheet of the sound absorbing composite is 0.1 to 1. Ocm.  6. The floor sound absorbing structure according to claim 1, wherein the through holes of the foam sheet of the sound absorbing composite have a diameter of 0.1 to 3 cm.  7. The floor sound absorbing structure according to claim 1, wherein the opening ratio of the through holes of the foam sheet of the sound absorbing composite is 1 to 80%.  8. The through-hole of the foam sheet of the sound-absorbing composite is tapered in the thickness direction, and the diameter of the through-hole gradually decreases from one foam sheet to the other foam sheet with the sound-absorbing film in between. The sound absorbing structure for a floor according to any one of claims 1, 5 to 7, characterized in that:  9. The floor sound absorbing structure according to claim 1, wherein the thickness of the sound absorbing layer is 0.5 to 5 cm.