Soundproofing material and method for manufacturing same

Abstract

To provide a soundproof material that can achieve improved soundproof performance and a method for producing the same.SOLUTION: A soundproof material 10 includes polyurethane foam 11 for sound absorption. The soundproof material 10 is produced by performing a sticking treatment to stick the tip of a needle or cutter to the middle point of the foamed and molded polyurethane foam at a plurality of sites.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] The present disclosure relates to acoustic insulation materials including foams and methods of making the same. [Background technology]

[0002] Patent Document 1 describes a soundproofing material containing polyurethane foam having open cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Jitszen No. 49-081516 (specification page 2) Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for improved soundproofing performance compared to the conventional soundproofing materials described above. [Means for solving the problem]

[0005] A first aspect of the invention made to solve the above problems is a method for manufacturing a soundproofing material containing sound-absorbing polyurethane foam, in which a piercing process is performed in multiple places to pierce the foam-molded polyurethane foam halfway with the tip of a needle or blade.

[0006] A second aspect of the invention is a method for manufacturing a soundproofing material as described in the first aspect, in which the piercing process is performed from one side of the polyurethane foam, and an incision process is performed to make incisions on the side of the polyurethane foam opposite the one side.

[0007] A third aspect of the invention is a method for producing a soundproofing material as described in the second aspect, wherein the polyurethane foam is shaped by molding, a high-density layer having an apparent density higher than that of the surface layer is formed as a surface layer of the polyurethane foam including the surface into which the compressed gas is blown in the blowing process, and the incisions are made deeper in the incision process than the high-density layer formed in the polyurethane foam.

[0008] A fourth aspect of the invention is a method for producing a soundproofing material according to any one of the first to third aspects, wherein a linear hydrocarbon wax is used as a release agent during expansion molding of the polyurethane foam.

[0009] A fifth aspect of the invention is a soundproofing material comprising sound-absorbing polyurethane foam, the soundproofing material having a plurality of puncture marks made by the tips of a needle or blade extending partway through the polyurethane foam.

[0010] A sixth aspect of the invention is the soundproofing material according to the fifth aspect, wherein the width of the puncture marks is equal to or greater than a cell diameter of the foam cells of the polyurethane foam.

[0011] A seventh aspect of the invention is the soundproofing material according to the fifth or sixth aspect, wherein the plurality of puncture marks are arranged in a lattice pattern.

[0012] An eighth aspect of the invention is a soundproofing material described in any one of the fifth to seventh aspects, in which the surface of the polyurethane foam has a first surface included in a surface side portion in which the number of closed cells per unit cross-sectional area of ​​the foam cells of the polyurethane foam is smaller than that inside the polyurethane foam, and the multiple puncture marks extend from the first surface into the interior of the polyurethane foam.

[0013] A ninth aspect of the invention is a soundproofing material described in any one of the fifth to seventh aspects, in which the surface of the polyurethane foam has a first surface included in the surface side portion where the air permeability of the polyurethane foam is greater than that of the interior of the polyurethane foam, and the puncture marks extend from the first surface into the interior of the polyurethane foam.

[0014] A tenth aspect of the invention is a soundproofing material according to the eighth or ninth aspect, in which a skin material is integrated with the first surface of the polyurethane foam, and the puncture marks penetrate the impregnated layer.

[0015] An eleventh aspect of the invention is the soundproofing material according to the eighth or ninth aspect, in which a skin material is integrated with the polyurethane foam on the side opposite the first surface, and the puncture marks extend from the first surface toward the skin material side.

[0016] A twelfth aspect of the invention is the soundproofing material according to any one of the eighth to eleventh aspects, wherein the polyurethane foam has a flat shape and has the first surface on one of its front and back sides, and the ratio of the major axis to the minor axis of a foam cell in the central part of the thickness direction of the polyurethane foam is 1 to 1.5.

[0017] A thirteenth aspect of the invention is a soundproofing material according to any one of the eighth to twelfth aspects, wherein the polyurethane foam has a flat shape and has the first surface on one of the front and back sides, and the ratio of the number of closed cells per unit cross-sectional area in a surface portion of the polyurethane foam up to a depth of 3 mm from the first surface to the number of closed cells per unit cross-sectional area in a central portion of the polyurethane foam in the thickness direction is 0.7 or less.

[0018] A 14th aspect of the invention is a soundproofing material according to any one of the 8th to 13th aspects, wherein the ratio of the number of open cells to the total number of foamed cells of the polyurethane foam is greater nearer the first surface than nearer the interior of the polyurethane foam.

[0019] A fifteenth aspect of the present invention is the soundproofing material according to any one of the fifth to fourteenth aspects, wherein the polyurethane foam has a 50% compression hardness of 500N to 3000N based on the E method of JIS K6400-2:2012. Effect of the Invention

[0020] In the first aspect of the invention, the tip of a needle or blade is pierced partway through the foamed polyurethane foam at multiple locations, making it easier for sound (air) to penetrate into the polyurethane foam. This makes it possible to improve the sound absorption performance of the polyurethane foam and improve the soundproofing performance of the soundproofing material.

[0021] As in the second aspect of the invention, a cutting process may be performed in which cuts are made in the polyurethane foam. This cut also makes it easier for sound (air) to penetrate into the polyurethane foam. This makes it possible to improve the sound absorption performance of the polyurethane foam and improve the soundproofing performance of the soundproofing material. Also, in the second aspect of the invention, the cutting process is performed on the surface of the polyurethane foam opposite to the surface that has been pierced, making it possible to improve the sound absorption of the polyurethane foam against sounds coming from both sides of the polyurethane foam.

[0022] In a third aspect of the invention, the polyurethane foam is molded and the incisions are made deeper than the skin layer formed on the polyurethane foam in the incision process, which makes it easier for the polyurethane foam to be ventilated deeper than the skin layer, thereby further improving the sound absorption of the polyurethane foam.

[0023] In the fourth aspect of the invention, a linear hydrocarbon wax is used as a release agent during foam molding of polyurethane foam, which makes it easier for foam cells to open on the surface of the polyurethane foam and makes it easier to inject compressed gas into the polyurethane foam from this surface.

[0024] The soundproofing material of the fifth aspect of the invention has puncture marks made by the tips of a plurality of needles or blades extending halfway through the sound-absorbing polyurethane foam. These puncture marks make it easier for sound (air) to penetrate into the polyurethane foam. This makes it possible to improve the sound absorption performance of the polyurethane foam and to improve the soundproofing performance of the soundproofing material.

[0025] In the sixth aspect of the invention, the width of the needle puncture in the polyurethane foam is equal to or larger than the cell diameter of the foamed cells, making it possible to facilitate ventilation to the inside of the polyurethane foam.

[0026] As in the seventh aspect of the invention, the plurality of punctures may be arranged, for example, in a lattice pattern, which makes it possible to broaden the range of the polyurethane foam in which sound absorption can be improved.

[0027] In the soundproofing material of the eighth aspect of the invention, the needle punctures extend from the first surface of the polyurethane foam to the inside, and the number of closed cells per unit cross-sectional area of ​​the foam cells is smaller in the surface side portion including the first surface than in the interior of the polyurethane foam. This makes it possible to increase the number of connected open cells closer to the first surface than in the interior of the polyurethane foam. In addition, in the soundproofing material of the ninth aspect of the invention, the air permeability of the polyurethane foam is larger in the surface side portion including the first surface than in the interior of the polyurethane foam. These configurations make it possible to increase the air permeability of the surface side portion of the polyurethane foam, and to increase the sound absorption performance of the polyurethane foam against the sound from the surface side, thereby making it possible to improve the soundproofing performance of the soundproofing material. In addition, since the air permeability can be reduced in the interior of the polyurethane foam compared to the surface side, it is also possible to improve the sound insulation of the polyurethane foam.

[0028] In a tenth aspect of the invention, a skin material is integrated with the first surface of the polyurethane foam. Here, the needle punctures penetrate the skin material and extend to the inside of the polyurethane foam. Therefore, it is possible to allow ventilation from the first surface to the inside of the polyurethane foam through the skin material, and it is possible to improve the sound absorption properties of the polyurethane foam.

[0029] In an eleventh aspect of the invention, a skin material is integrated with the polyurethane foam on the side opposite to the first surface, and the needle punctures extend from the first surface toward the skin material. This allows sound to easily enter the polyurethane foam from the first surface, and the sound absorption of the polyurethane foam can be further improved. Furthermore, according to the present invention, it is possible for the skin material to insulate sound that enters the polyurethane foam from the first surface.

[0030] As in the twelfth aspect of the invention, the polyurethane foam may have a flat shape, and the ratio of the major axis to the minor axis of the foam cells at the center in the thickness direction of the polyurethane foam may be 1 to 1.5. When the ratio of the major axis to the minor axis of the foam cells is within this range, the polyurethane foam can exhibit good restoring properties in both the major axis and minor axis directions of the foam cells.

[0031] In a thirteenth aspect of the invention, the polyurethane foam has a flat shape and a first surface on at least one of the front and back sides, and the ratio of the number of closed cells per unit cross-sectional area in a surface layer portion from the first surface to a depth of 3 mm to the number of closed cells per unit cross-sectional area in a central portion in a thickness direction of the polyurethane foam is 0.7 or less. With this configuration, it is possible to particularly improve the sound absorbing performance of the polyurethane foam.

[0032] In a fourteenth aspect of the invention, the ratio of the number of open cells to the total number of foam cells is greater closer to the surface than to the inside of the polyurethane foam. This configuration improves the air permeability on the surface side of the polyurethane foam, making it easier for air to reach the inside of the polyurethane foam, and makes it possible to further improve the sound absorbing performance of the polyurethane foam.

[0033] In the fifteenth aspect of the invention, the 50% compression hardness of the polyurethane foam is 500 to 3000 N, so that it is possible to ensure rigidity. This makes it possible to stabilize the shape of the polyurethane foam. In a polyurethane foam having a 50% compression hardness in the above range, for example, when a break hole is formed in the cell membrane by roll crushing, the polyurethane foam is easily crushed, resulting in low dimensional accuracy, or wrinkles, resulting in poor appearance. However, in the configuration of the present invention, roll crushing is not necessary, so that it is possible to suppress the decrease in dimensional accuracy and the deterioration of the appearance of the polyurethane foam. [Brief description of the drawings]

[0034] [Figure 1] (A) is a side cross-sectional view of the soundproofing material according to the first embodiment, and (B) is a bottom view of the soundproofing material. [Diagram 2] Enlarged cross-sectional side view of polyurethane foam cells [Diagram 3] Side cross-sectional view of polyurethane foam undergoing piercing [Figure 4] Side cross-sectional view showing an example of soundproofing material use [Diagram 5] FIG. 11 is a cross-sectional side view of a soundproofing material according to a second embodiment being blow-treated; [Figure 6] Enlarged cross-sectional side view of polyurethane foam cells [Figure 7] Enlarged cross-sectional side view of polyurethane foam soundproofing material [Figure 8] FIG. 3A is a side cross-sectional view of a soundproofing material according to a third embodiment; [Figure 9] Enlarged cross-sectional side view of polyurethane foam cells [Figure 10] Enlarged cross-sectional side view of polyurethane foam soundproofing material [Figure 11] (A) A side cross-sectional view of the mold in an open state and the skin material fixed to the mold, (B) A side cross-sectional view of the mold and the skin material when the mold is open and raw material is being injected [Figure 12](A) A side cross-sectional view of the mold and skin when the mold is closed and the raw material begins to foam, (B) A side cross-sectional view of the polyurethane foam and skin that have been foamed in the mold. [Figure 13] Side cross-sectional view of polyurethane foam being pierced from the exposed side [Figure 14] A cross-sectional side view of a polyurethane foam being pierced from the skin side. [Figure 15] Side cross-sectional view of soundproofing material with polyurethane foam surface being blown [Figure 16] A cross-sectional side view of a soundproofing material being blown from the skin side. [Figure 17] Side cross-sectional view showing an example of soundproofing material use [Figure 18] 4 is a cross-sectional side view of a soundproofing material according to a fourth embodiment. [Figure 19] (A) A side cross-sectional view of the mold in an open state and the skin material fixed to the mold, (B) A side cross-sectional view of the mold and the skin material when the mold is open and raw material is being injected [Figure 20] (A) A side cross-sectional view of the mold and skin when the mold is closed and the raw material begins to foam, (B) A side cross-sectional view of the polyurethane foam and skin that have been foamed in the mold. [Figure 21] A cross-sectional side view of a soundproofing material being blown from the skin side. [Figure 22] Side cross-sectional view showing an example of soundproofing material use [Diagram 23] 5 is a perspective view of a soundproofing material according to a fifth embodiment. [Figure 24] Enlarged image of foam cells on the outer surface of polyurethane foam [Diagram 25] Table showing examples and comparative examples [Figure 26] Table showing examples and comparative examples DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] [First embodiment] As shown in Fig. 1(A), the soundproofing material 10 according to the first embodiment is made of polyurethane foam 11. In this embodiment, the polyurethane foam 11 has a flat shape, has open cells, and has sound absorbing properties. The flat shape includes a plate shape and other flat shapes, and also includes shapes with irregularities formed on the front or back surface. In this embodiment, the polyurethane foam 11 has a flat plate shape.

[0036] The polyurethane foam 11 is preferably a semi-rigid polyurethane foam. Since a soft polyurethane foam is soft and has low rigidity, and a rigid polyurethane foam is hard and too rigid, a semi-rigid polyurethane foam having a suitable rigidity is more preferable. As the semi-rigid polyurethane foam, for example, one having a 50% compression hardness of 500 to 3000 N based on the E method of JIS K6400-2:2012 is preferable.

[0037] The apparent density of the polyurethane foam 11 (based on JIS K7222:2005) is 30 to 90 kg / m 3 It is preferable that the apparent density is 40 kg / m 3 If the thickness is more than this, the rigidity of the polyurethane foam 11 can be ensured and the apparent density is 60 kg / m 3 The thickness being equal to or less is particularly preferable in terms of reducing the weight of the polyurethane foam 11. The thickness of the polyurethane foam 11 is, for example, 1 to 50 mm.

[0038] As shown in FIG. 2, the polyurethane foam 11 has foam cells 30 densely packed. The foam cells 30 include open cells 30A and closed cells 30B. The open cells 30A communicate with each other through cell holes 32 penetrating the cell membrane 31 that separates the foam cells 30. The closed cells 30B are surrounded by cell membranes 31 that do not have cell holes 32, and do not communicate with other foam cells 30. Here, in the present disclosure, the presence or absence of cell holes 32 is determined in an image of the polyurethane foam 11 magnified 35 times with a microscope (e.g., SEM, etc.), and when the cell holes 32 are not visible in the cell membrane 31 surrounding the foam cells 30, the foam cells 30 are determined to be closed cells 30B. For example, the polyurethane foam 11 contains 20 to 150 foam cells 30 per 25 mm.

[0039] As shown in FIG. 1 and FIG. 2, the polyurethane foam 11 has a sound absorbing structure 40 including a sound absorbing surface 11M that allows sound (air) to enter the polyurethane foam 11 and a sound absorbing path 33 that communicates from the sound absorbing surface 11M to the inside of the polyurethane foam 11. In detail, as shown in FIG. 2, the sound absorbing surface 11M is a surface of the polyurethane foam 11 where the open cells 30A of the foam cells 30 are open. The sound absorbing path 33 is formed of a plurality of open cells 30A that communicate from the sound absorbing surface 11M toward the inside of the polyurethane foam 11. The sound absorbing surface 11M of the polyurethane foam 11 may not have a skin layer, or may have a breathable skin layer. Here, in the present disclosure, the skin layer refers to a surface layer that has a higher apparent density than the inner part of the polyurethane foam 11, for example, a part from the surface of the polyurethane foam 11 to a depth of 0.5 to 1 mm. For example, in FIG. 24, the polyurethane foam 11 is shown with its surface facing up, with the skin layer designated by the numeral 16 .

[0040] 1(A) and 1(B), in the soundproofing material 10 of this embodiment, a plurality of puncture marks 18 are formed by piercing the polyurethane foam 11 with the tip of a needle. Specifically, the puncture marks 18 extend from one of the front and back surfaces (open cell surface 11MA) of the polyurethane foam 11 to the middle of the polyurethane foam 11, and these puncture marks 18 are arranged in a lattice pattern (for example, a square lattice pattern or a staggered arrangement) with a predetermined interval between them. The plurality of puncture marks 18 may also be arranged randomly.

[0041] The puncture marks 18 may be formed on both the front and back sides of the polyurethane foam 11. In this case, it is preferable that the needle puncture marks 18 on the front and back sides of the polyurethane foam 11 are offset from each other so as not to overlap in the thickness direction of the polyurethane foam 11. This can prevent a decrease in the rigidity of the polyurethane foam 11.

[0042] The depth of the puncture marks 18 may be up to the center of the polyurethane foam 11 in the thickness direction, or may be up to a position closer to one or the other of the front and back surfaces of the polyurethane foam 11. For example, when the polyurethane foam 11 is molded, a skin layer is likely to be formed on the surface of the polyurethane foam 11. In this case, it is preferable that the depth of the puncture marks 18 is set to a position deeper than the skin layer of the polyurethane foam 11. This makes it easier to allow ventilation to a position deeper than the skin layer of the polyurethane foam 11. It is preferable that the skin layer of the polyurethane foam 11 is breathable, that is, that the open cells 30A are open on the surface, and such a skin layer can be easily formed by using a linear hydrocarbon wax as a release agent during foam molding of the polyurethane foam 11.

[0043] In this embodiment, the width of the puncture mark 18 (specifically, the maximum size when viewed in the puncture direction) is equal to or larger than the cell diameter (specifically, the major axis, which is the length of the longest part) of the foamed cell 30. The thickness of the puncture mark 18 may be larger or smaller than the cell diameter of the foamed cell 30.

[0044] The soundproofing material 10 is manufactured, for example, as follows. To manufacture the soundproofing material 10, first, the polyurethane foam 11 is obtained by foam molding in a mold (i.e., by molding). The polyurethane foam 11 may also be formed by slab molding.

[0045] When foam molding polyurethane foam 11, it is preferable to use, for example, a straight-chain hydrocarbon wax as a mold release agent. This makes it easy to form open cell surface 11MA (i.e., a breathable surface) where foam cells 30 including open cells 30A are open on the surface of polyurethane foam 11. Specifically, the straight-chain hydrocarbon wax is applied to the molding surface of a foam molding mold for molding open cell surface 11MA, and then polyurethane raw material is injected into the mold and foamed and cured to form polyurethane foam 11.

[0046] Examples of the linear hydrocarbon wax include paraffin wax, Fischer-Tropsch wax, and Sasol wax, and it is possible to use a solvent-based release agent dispersed in an organic solvent, or a water-based release agent dispersed in water using an emulsifier, etc. Examples of the branched hydrocarbon wax include microcrystalline wax and modified polyethylene wax, and it is possible to use a solvent-based release agent or a water-based release agent, etc.

[0047] Next, as shown in FIG. 3, a plurality of needle prick marks 18 are formed on one of the front and back surfaces of the polyurethane foam 11. Specifically, the polyurethane foam 11 is arranged so that one surface faces upward, and a press mold 57 (which may be, for example, a pin holder, etc.) having a plurality of (for example, lattice-shaped) needles 58 protruding from its underside is pressed from above. In this manner, a piercing process in which the needles 58 are pierced halfway into the polyurethane foam 11 (more specifically, a piercing process in which the needles 58 are pierced and then removed) is performed, and the needle prick marks 18 arranged in a lattice are formed. Here, since the polyurethane foam 11 has restoring properties, the piercing marks 18 may close when the press mold 57 is returned, but even in this case, the piercing marks 18 can be confirmed, for example, by enlarging a cut surface of the polyurethane foam 11 with a microscope or the like.

[0048] In this embodiment, the needles 58 of the press die 57 are, for example, as follows. The needles 58 are composed of a cylindrical body portion that is the base end side and a triangular pyramid-shaped tip portion. The diameter of the body portion of the needles 58 is 1.35 mm, and the axial length of the body portion is 9 mm. The axial length of the tip portion of the needles 58 is 4 mm. The needles 58 are arranged in a square lattice pattern, and the lattice spacing (the spacing between the central axes of adjacent needles 58) is 3.65 mm. In this embodiment, for example, the press die 57 is pressed to such an extent that only the tips of the needles 58 are pierced into the polyurethane foam 11. The shape and arrangement of the needles 58 are not limited to this example. The piercing process may be performed by piercing the same needles 58 into multiple places without using the press die 57 provided with multiple needles 58.

[0049] When the piercing process is completed, the soundproofing material 10 of this embodiment is completed. The piercing process may be performed from both the front and back sides of the polyurethane foam 11. In this case, as described above, it is preferable that the needle piercing marks 18 on the front and back sides of the polyurethane foam 11 are arranged in a shifted manner so as not to overlap with each other in the thickness direction of the polyurethane foam 11. This can suppress a decrease in the rigidity of the polyurethane foam 11. In addition, when the piercing process is performed on one of the front and back sides of the polyurethane foam 11, a cutting process may be performed to make incisions 13 on the other side of the polyurethane foam 11 (see FIG. 23 and the fifth embodiment described later). In this case, the incisions may be linear, parallel, or lattice-shaped, and are preferably arranged so as not to overlap with the piercing marks 18 when viewed from the thickness direction of the polyurethane foam 11. This can suppress a decrease in the rigidity of the polyurethane foam 11.

[0050] The details of the raw materials for polyurethane foam 11 are as follows:

[0051] The polyol component may be any of known ether polyols, ester polyols, ether ester polyols, polymer polyols, etc., used in the production of polyurethane foams, either alone or in combination. Examples of ether polyols include polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, and trimethylolpropane, or polyether polyols obtained by adding alkylene oxides such as ethylene oxide and propylene oxide to the polyhydric alcohols. Examples of ester polyols include polyester polyols obtained by polycondensation of aliphatic carboxylic acids such as malonic acid, succinic acid, and adipic acid, or aromatic carboxylic acids such as phthalic acid, and aliphatic glycols such as ethylene glycol, diethylene glycol, and propylene glycol. Furthermore, ether ester polyols containing both ether groups and ester groups in the polyol, or polymer polyols obtained by polymerizing an ethylenically unsaturated compound in an ether polyol, may also be used.

[0052] The polyisocyanate component may be any of aromatic, alicyclic, and aliphatic isocyanates, and may be a bifunctional isocyanate having two isocyanate groups in one molecule, a trifunctional or higher isocyanate having three or more isocyanate groups in one molecule, or a modified product thereof (e.g., a urethane-modified, allophanate-modified, biuret-modified, or other modified product), and these may be used alone or in combination. Examples of bifunctional isocyanates include aromatic isocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate, and 2,2'-diphenylmethane diisocyanate, alicyclic isocyanates such as cyclohexane-1,4-diisocyanate and isophorone diisocyanate, and aliphatic isocyanates such as butane-1,4-diisocyanate, hexamethylene diisocyanate, and lysine isocyanate. Examples of trifunctional or higher isocyanates include 1-methylbenzene-2,4,6-triisocyanate, 1,3,5-trimethylbenzene-2,4,6-triisocyanate, and polymeric MDI (polymethylene polyphenyl polyisocyanate).

[0053] The blowing agent is not particularly limited, but water is preferred. Carbon dioxide gas, pentane, hydrofluoroolefin (HFO), etc. may be used as a blowing assistant in combination with water as the blowing agent.

[0054] The catalyst may be any known catalyst used in the production of polyurethane foam. Examples include amine catalysts such as diethanolamine, triethylenediamine, bis(2-dimethylaminoethyl)ether, N,N,N',N",N"-pentamethyldiethylenetriamine, tetramethylguanidine, and imidazole-based compounds; tin catalysts such as stannous octoate; and metal catalysts (also called organometallic catalysts) such as phenylmercury propionate and lead octenate. A combination of multiple catalysts may be used.

[0055] The raw material of polyurethane foam 11 may contain a foam stabilizer. Any known foam stabilizer used in the production of polyurethane foams may be used, such as silicone-based foam stabilizers and non-silicone surfactants.

[0056] The raw materials for polyurethane foam 11 are prepared in two parts: Liquid A, which is a mixture of a polyol component, a blowing agent, a catalyst, etc., and Liquid B, which contains a polyisocyanate component. If the raw materials for polyurethane foam 11 contain a foam stabilizer, this is mixed into Liquid A. This concludes the description of the raw materials for polyurethane foam 11.

[0057] In this embodiment, the needle puncture mark 18 is formed in the polyurethane foam 11, so that sound (air) can easily penetrate into the polyurethane foam 11, improving the sound absorption performance of the polyurethane foam 11 and improving the sound insulation of the soundproofing material 10. Furthermore, by forming such puncture marks 18 in the polyurethane foam 11 to a position deeper than the skin layer, it is possible to facilitate ventilation to a position deeper than the skin layer, improving the sound absorption of the polyurethane foam 11. The puncture marks 18 may be formed by piercing the polyurethane foam 11 halfway with the tip of a blade. The soundproofing material 10 having such puncture marks 18 can also improve the sound absorption.

[0058] Furthermore, since the multiple punctures are arranged, for example, in a lattice pattern, it is possible to widen the range of the polyurethane foam in which the sound absorption properties can be improved.

[0059] The polyurethane foam 11 may be subjected to a cutting process in which cuts 13 are made. This cut also makes it easier for sound (air) to penetrate into the polyurethane foam. This makes it possible to improve the sound absorption performance of the polyurethane foam 11, and therefore the soundproofing performance of the soundproofing material 10. In addition, the cut is made on the surface of the polyurethane foam 11 opposite to the surface that has been pierced, so that it is possible to improve the sound absorption performance of the polyurethane foam 11 against sounds from both sides of the polyurethane foam 11. The width of the puncture marks 18 in the polyurethane foam 11 is equal to or larger than the cell diameter of the foam cells, so that it is possible to easily allow air to pass through to the inside of the polyurethane foam 11.

[0060] In addition, by forming the polyurethane foam 11 by molding and making the cuts in the cutting process deeper than the skin layer formed on the polyurethane foam 11, it is possible to facilitate ventilation of the polyurethane foam 11 deeper than the skin layer, and the sound absorption properties of the polyurethane foam 11 can be further improved.

[0061] FIG. 4 shows an example of the use of the soundproofing material 10 of this embodiment. In this example, the soundproofing material 10 is provided in a soundproofing structure of a building or vehicle. Specifically, in this soundproofing structure, the soundproofing material 10 is sandwiched between a pair of plate-shaped sound-insulating materials 71, 72 in a close contact state or spaced apart from each other. When the soundproofing material 10 is in a close contact state, the soundproofing material 10 may be closely contacted to the sound-insulating materials 71, 72 in a non-adhesive state. Examples of the sound-insulating materials 71, 72 include steel plates, gypsum boards, concrete, and other materials having sound insulation properties, such as double floors, double walls, and double ceilings of buildings, and body panels of vehicles such as vehicles and sound-insulating mats that are layered thereon. In this way, according to a soundproofing structure in which the soundproofing material 10 of this embodiment is arranged between a pair of sound-insulating materials 71, 72, it is possible to improve sound absorption performance and sound insulation performance.

[0062] [Second embodiment] The soundproofing material 10 of this embodiment differs from the first embodiment in that a blowing process is performed as an additional process by blowing compressed gas into the interior of polyurethane foam 11 that has been foam-molded in the same manner as in the first embodiment (see Figure 5).

[0063] As shown in Fig. 6, in the soundproofing material 10 of this embodiment, the cell holes 32 of the polyurethane foam 11 are formed as foam holes 32X formed during foam molding of the polyurethane foam 11 and rupture holes 32Y formed by rupturing the cell membrane 31 after foam molding (see Fig. 5). Specifically, as described later, the rupture holes 32Y are formed by rupturing the cell membrane 31 by the wind pressure of compressed gas blown into the polyurethane foam 11 from the surface (sound absorbing surface 11M) thereof. For example, the rupture holes 32Y may have ruptured cell membrane 31 attached to the opening edge of the rupture holes 32Y.

[0064] In this embodiment, the sound absorbing structure 40 of the polyurethane foam 11 is structured such that the total opening area of ​​the cell holes 32, including the foaming holes 32X and the broken holes Y, is larger closer to the sound absorbing surface 11M than to the inside of the polyurethane foam. In addition, in the sound absorbing structure 40, the air permeability of the polyurethane foam 11 is larger closer to the sound absorbing surface 11M than to the inside of the polyurethane foam 11. With these configurations, the air permeability of the polyurethane foam 11 on the sound absorbing surface 11M side is improved, and it is possible to improve the sound absorbing performance of the polyurethane foam 11 (i.e., the soundproofing material 10) against the sound from the sound absorbing surface 11M side. The above-mentioned total opening area can be compared, for example, by calculating the area of ​​the cell holes 32 in an enlarged image of a predetermined region (for example, the surface side region S and the central region D shown in FIG. 7) of the cut surface of the polyurethane foam 11 using area calculation software or the like, and comparing them at different depths from the sound absorbing surface 11M. In detail, since the direction in which the cell holes 32 are opened is random and isotropic as a whole, it is sufficient to measure the total planar area of ​​the cell holes 32 in a predetermined region of a cut surface in any direction and compare them at points of different depths. Also, the air permeability of polyurethane foam 11 can be compared, for example, by dividing polyurethane foam 11 into three equal parts in the thickness direction and measuring the air permeability (based on JIS K6400-7 Method B:2012) between the central part in the thickness direction and the part on the sound absorbing surface 11M side.

[0065] In the sound absorbing structure 40 of the polyurethane foam 11, the number of closed cells 30B is smaller closer to the sound absorbing surface 11M than to the inside of the polyurethane foam 11. Specifically, the closed cell ratio, which is the ratio of the number of closed cells 30B in the surface layer portion 10S from the sound absorbing surface 11M to a depth of 3 mm to the number of closed cells 30B per unit cross-sectional area in the central portion in the thickness direction of the polyurethane foam 11, is preferably 0.7 or less. Here, the central portion in the thickness direction of the polyurethane foam 11 refers to a region (e.g., the central region D shown in FIG. 7) that is disposed inside the surface layer portion 10S and includes the central position 10D in the thickness direction of the polyurethane foam 11 (in the example of this embodiment, the position at a depth of 10 mm from the sound absorbing surface 11M). A configuration in which the closed cell ratio is 0.7 or less makes it possible to particularly improve the sound absorbing performance of the polyurethane foam 11. This closed cell ratio is more preferably 0.65 or less, and even more preferably 0.6 or less. In the present embodiment, the ratio of the number of open cells 30A to the total number of foamed cells 30 in the sound absorbing structure 40 is higher closer to the sound absorbing surface 11M than to the inside of the polyurethane foam 11. This configuration also improves the air permeability of the polyurethane foam 11 on the sound absorbing surface 11M side, making it easier to allow air to pass through to the inside of the polyurethane foam 11, and thus makes it possible to further improve the sound absorbing performance of the polyurethane foam. The number of closed cells 30B and open cells 30A per unit cross-sectional area can be obtained, for example, by counting the number of closed cells 30B and open cells 30A in an enlarged image (e.g., SEM image, etc.) of a surface side region S of a predetermined area included in the surface layer portion 10S of the cut surface (e.g., outer peripheral surface 11E) of the polyurethane foam 11 and a central region D of a predetermined area including the central position 10D (see FIG. 7). Then, by comparing the numbers between the above-mentioned regions of the polyurethane foam 11 at different depths from the sound absorbing surface 11M, the closed cell ratio, etc. can be obtained.

[0066] In the polyurethane foam 11 of the soundproofing material 10, the ratio of the major axis to the minor axis of the foam cells 30 in the central portion (central region D) in the thickness direction (major axis / minor axis ratio) is preferably 1 to 1.5. The major axis is the length of the longest part of the foam cells 30, and the minor axis is the length of the smallest part of the foam cells 30. The directions of the major axis and the minor axis differ for each foam cell 30, but generally, the major axis direction is substantially perpendicular to the thickness direction, and the minor axis direction is substantially the same as the thickness direction. This major axis / minor axis ratio can be calculated, for example, from the ratio of the average major axis and the average minor axis of the total of five foam cells, including the largest foam cell 30, the smallest foam cell 30, and any other three foam cells 30 among the foam cells 30 shown in the enlarged image of the central region D (see FIG. 7). When the ratio of the major axis to the minor axis of foam cells 30 is in the range of 1 to 1.5, polyurethane foam 11 can exhibit good restorability in both the major axis and minor axis directions of the foam cells.

[0067] In this embodiment, both the front and back surfaces of the polyurethane foam 11 are sound absorbing surfaces 11M, and both the front and back surfaces are provided with the sound absorbing structures 40. The sound absorbing surfaces 11M may be disposed on the entire outer surface of the polyurethane foam 11, or may be disposed on only one of the front and back surfaces.

[0068] In this embodiment, the outer peripheral surface 11E of the polyurethane foam 11 is a cut surface where no skin layer is formed. In addition, in the outer peripheral surface 11E, the part of the cell membrane 31 where the cell holes 32 are not open reflects light and is easy to shine. That is, when there are many closed cells 30B, there are many parts that are easy to shine. On the other hand, the part of the cell membrane 31 where the total opening area of ​​the cell holes 32 is large is difficult to shine. Therefore, when looking at the outer peripheral surface 11E of the polyurethane foam 11 of this embodiment, it becomes difficult to shine from the center in the thickness direction to the front and back sound absorbing surfaces 11M. In this embodiment, the surface layer portion 10S having the front and back sound absorbing surfaces 11M is a layered region that is difficult to shine compared to the deeper parts, and the break holes 32Y are unevenly distributed in this layered region.

[0069] The soundproofing material 10 is manufactured, for example, as follows. To manufacture the soundproofing material 10, first, similarly to the above-mentioned first embodiment, polyurethane foam 11 is obtained by foam molding in a mold (i.e., by molding). The polyurethane foam 11 may be formed by slab molding. After molding, the polyurethane foam 11 is appropriately cut, and then, similarly to the above-mentioned first embodiment, a piercing process is performed from at least one open cell surface 11M of the polyurethane foam 11. The polyurethane foam 11 may be subjected to the above-mentioned incision process.

[0070] Next, a blowing process is performed as shown in Fig. 5. In the blowing process, a compressed gas is blown into polyurethane foam 11 to break cell membranes 31 of foam cells 30 of polyurethane foam 11, thereby forming breakage holes 32Y.

[0071] Specifically, in the blowing process, compressed gas (e.g., air) is blown into the open cell surface 11MA on the front and back sides of the polyurethane foam 11. In detail, as shown in FIG. 5, the blowing process is performed by bringing the tip surface of a nozzle N of a blow gun that ejects compressed gas (i.e., the opening edge of the ejection port) into contact with the open cell surface 11MA of the polyurethane foam 11. The blowing process may be performed by bringing the nozzle N close to the open cell surface 11MA (e.g., by separating it by a distance of 2 mm or less). These methods make it easier to blow the compressed gas into the polyurethane foam 11, and also make it possible to suppress variation in the amount of compressed gas blown in. In this case, the dynamic pressure of the compressed gas blown into the polyurethane foam 11 is preferably set to 0.1 to 1.0 MPa. This makes it easier to form a sound absorbing path to the inside of the polyurethane foam 11. The compressed gas used in the blowing process may be an inert gas such as nitrogen or argon, other than air.

[0072] When the blowing process is performed, the total opening area of ​​the foamed holes 32X formed during foaming increases, particularly in the portion of the polyurethane foam 11 near the open cell surface 11MA, and rupture holes 32Y are formed in the polyurethane foam 11, adding sound absorbing paths 33. This forms the sound absorbing structure 40. At this time, the sound absorbing surface 11M is formed from the open cell surface 11MA.

[0073] In this embodiment, the blowing process is performed over the entire front and back surfaces of the polyurethane foam 11, but may be performed only on a part of the surface. For example, the blowing process may be performed only on the entire front or back surface, or may be performed only on a part of at least one of the front and back surfaces. For example, if the nozzle N of the blow gun used in the blowing process is shaped like a letter T, the nozzle N can be made wider to eject the compressed gas, thereby making the blowing process more efficient. The blowing process may be performed while feeding the polyurethane foam 11. In this case, it is preferable to perform the blowing process with the nozzle N close to the polyurethane foam 11 without abutting it. In this case, the blowing process can be performed more efficiently by using a T-shaped nozzle N wider than the polyurethane foam 11.

[0074] The blowing process may be performed on only one of the surfaces of the polyurethane foam 11. If the blowing process is performed on the open cell surface 11M that has been pierced, it becomes easier to blow the compressed gas into the interior of the polyurethane foam 11 through the puncture marks formed by the piercing process. In addition, before the blowing process, a cutter or other cutter may be used to make cuts in the open cell surface 11M. The cutter-treated open cell surface 11M also makes it easier to blow the compressed gas into the interior of the polyurethane foam 11 through the cuts. The piercing and cutter processes are particularly effective when the blowing process is performed on the surface of the polyurethane foam 11 on which the skin layer is formed. In this case, the perforations or cuts are formed to a depth that does not penetrate the polyurethane foam 11 and is deeper than the skin layer, making it easier to blow the compressed gas into the interior of the polyurethane foam 11. When the perforations or cuts are formed on both the front and back sides of the polyurethane foam 11, it is preferable to form the perforations or cuts at positions that do not overlap when viewed from the thickness direction. In this way, the rigidity of the polyurethane foam 11 can be suppressed from decreasing.

[0075] When the above-mentioned blowing process is finished, the soundproofing material 10 of this embodiment is completed. In this manner, in this embodiment, by performing the blowing process on the surface of the polyurethane foam 11 to communicate the foam cells 30 with each other through the rupture holes 32Y, it is possible to provide a sound absorbing structure in which the amount of air permeation is larger and the total opening area of ​​the cell holes 32 is larger the closer to the surface from the inside.

[0076] In the manufacturing method of the soundproofing material 10 of this embodiment, a blowing process is performed in which compressed gas is blown into the polyurethane foam 11 from the open cell surface 11MA to add rupture holes 32Y to the cell membrane 31 of the multiple foamed cells 30, and a sound absorbing path 33 is added that communicates from the sound absorbing surface 11M of the polyurethane foam 11 to the inside. Therefore, the sound absorbing performance of the polyurethane foam 11 can be improved, and the sound absorbing performance of the soundproofing material 10 can be improved. In addition, in this embodiment, the air permeability inside the polyurethane foam 11 can be reduced from the sound absorbing surface 11M, thereby improving the sound insulation of the polyurethane foam 11. As a result, the soundproofing performance of the soundproofing material 10 can be improved.

[0077] In this embodiment, the cell membrane is broken by the wind pressure of the compressed gas during the blowing process, so that the breakage holes 32Y can be easily formed in the polyurethane foam 11. Also, in this embodiment, the compressed gas can be blown into the interior of the polyurethane foam 11 through the puncture marks 18 during the blowing process, so that the compressed gas can be easily blown into the interior of the polyurethane foam 11.

[0078] In the soundproofing material 10 of the present embodiment, the total opening area of ​​the cell holes 32, including the foaming holes 32X and the rupture holes 32Y formed in the cell membrane 31 during foaming of the polyurethane foam 11, is larger closer to the surface (sound absorbing surface 11M) than to the inside of the polyurethane foam 11. Also, the air permeability of the polyurethane foam 11 is larger closer to the sound absorbing surface 11M than to the inside of the polyurethane foam 11. With these configurations, it is possible to increase the air permeability of the part of the polyurethane foam 11 on the sound absorbing surface 11M side, and it is possible to improve the sound absorbing performance of the polyurethane foam 11 against the sound from the sound absorbing surface 11M side of the polyurethane foam 11, and as a result, it is possible to improve the soundproofing performance of the soundproofing material 10. In addition, since the air permeability can be lowered in the inside of the polyurethane foam than in the part on the sound absorbing surface 11M side, it is possible to improve the sound insulation of the polyurethane foam 11. Moreover, by making it easier for sound (air) to enter the inside of the polyurethane foam 11, it is possible to suppress the reflection of the sound incident on the sound absorbing surface 11M to the outside. As a result, it is possible to improve the soundproofing performance of the soundproofing material 10.

[0079] Furthermore, in polyurethane foam 11, the number of closed cells 30B that do not have cell holes 32 in cell membrane 31 is smaller closer to sound absorbing surface 11M than to the interior of polyurethane foam 11. This makes it possible to increase the number of open cells 30A that are connected by cell holes 32 among foam cells 30, thereby making it possible to increase air permeability closer to sound absorbing surface 11M than to the interior of polyurethane foam 11. This makes it possible to further improve the sound absorbing performance of polyurethane foam 11.

[0080] Furthermore, since the ratio of the number of closed cells per unit cross-sectional area in the surface portion 10S from the sound-absorbing surface 11M to a depth of 3 mm to the number of closed cells 30B per unit cross-sectional area in the central portion of the polyurethane foam 11 in the thickness direction is 0.7 or less, it is possible to particularly improve the sound absorption performance of the polyurethane foam 11.

[0081] Furthermore, by setting the 50% compression hardness of the polyurethane foam to 500 to 3000 N, it is possible to ensure the rigidity of the polyurethane foam 11 and to stabilize the shape of the polyurethane foam 11. In the polyurethane foam 11 having a 50% compression hardness in the above range, when a break hole 32Y is formed in the cell membrane 31 by, for example, roll crushing, the polyurethane foam 11 is likely to be crushed, resulting in reduced dimensional accuracy, or wrinkles, resulting in poor appearance. However, according to this embodiment, roll crushing is not necessary, so it is possible to prevent the polyurethane foam 11 from decreasing in dimensional accuracy or from deteriorating in appearance.

[0082] In the soundproofing material 10 of the present embodiment, the sound absorbing surface 11M and the sound absorbing path 33 are disposed on both sides of the polyurethane foam 11, so that the sound absorbing performance for the sound from both sides can be improved.

[0083] [Third embodiment] 8(A), soundproofing material 10Y according to the third embodiment has a skin material 20 integrated with part of the surface of polyurethane foam 11. In soundproofing material 10Y of the present embodiment, polyurethane foam 11 has a flat shape (specifically, a plate shape), and skin material 20 is integrated only on one of the surfaces, either the front or back side.

[0084] In this embodiment, the covering material 20 has air permeability. Specifically, the covering material 20 is made of a fiber sheet 21, and an impregnated layer 22 is formed in the covering material 20 by impregnating the fiber sheet 21 with the raw material 11G of the polyurethane foam 11 and curing the same, and the covering material 20 including the impregnated layer 22 has air permeability. The air permeability of the covering material 20 including the impregnated layer 22 based on JIS K6400-7 Method B:2012 is 3 to 90 ml / cm. 2 / s, and 5 to 80 ml / cm 2 The skin material 20 may be non-breathable, for example, a fiber sheet 21 impregnated with an impregnation layer 22 to make it non-breathable, or a resin film.

[0085] In detail, the skin material 20 of this embodiment is composed of two overlapping fiber sheets 21, 21. The impregnated layer 22 is formed to have approximately the same thickness as the inner fiber sheet 21A arranged on the polyurethane foam 11 side. In this embodiment, the outer fiber sheet 21B has a larger fiber diameter and basis weight than the inner fiber sheet 21A. For example, the inner fiber sheet 21A and the outer fiber sheet 21B are integrated by needle punching.

[0086] In this embodiment, puncture marks 18 similar to those in the first embodiment are formed in the polyurethane foam 11. Specifically, the puncture marks 18 extend from the sound absorbing surface 11M (exposed surface) of the polyurethane foam 11 opposite the skin material 20 to partway through the polyurethane foam 11 (FIG. 8(A)). Moreover, the puncture marks 18 are arranged in a lattice pattern when viewed from the thickness direction of the polyurethane foam 11 (FIG. 8(B)).

[0087] The polyurethane foam 11 of the soundproofing material 10Y of this embodiment has a sound absorbing structure having a sound absorbing surface 11M and a sound absorbing path 33 similar to the polyurethane foam 11 of the soundproofing material 10 of the second embodiment (FIG. 9). Specifically, this foam structure is provided on both sides of the polyurethane foam 11, the front and back of the skin material 20, and both sides become the sound absorbing surface 11M. Here, the foam structure having the sound absorbing surface 11M on the side opposite to the skin material 20 (the lower side of FIG. 8(A)) of the polyurethane foam 11 has the same closed cell ratio as the second embodiment, and it is preferable that the closed cell ratio is 0.7 or less even in the foam structure having the sound absorbing surface 11M covered by the skin material 20. In this embodiment, the close cell ratio is 0.7 or less even in the sound absorbing surface 11M on the skin material 20 side, so that it is possible to particularly improve the sound absorbing performance of the polyurethane foam 11 against the sound from the skin material 20 side. Here, the closed cell ratio refers to the ratio of the number of closed cells 30B (FIG. 9) per unit cross-sectional area in the central part in the thickness direction of polyurethane foam 11 (i.e., the part including central position 10D (FIG. 10) in the thickness direction) to the number of closed cells 30B (FIG. 9) per unit cross-sectional area in the surface layer portion 10S (FIG. 9) from the sound absorbing surface 11M covered with skin material 20 to a depth of 3 mm. From the viewpoint of improving the sound absorbing performance for sound on the skin material 20 side, the closed cell ratio is more preferably 0.65 or less, and even more preferably 0.60 or less.

[0088] The details of the skin material 20 are as follows: Examples of fibers constituting the fiber sheet 21 include polyethylene terephthalate (PET) fibers, polyester fibers, polypropylene fibers, polyamide fibers, acrylic fibers, vinylon fibers, polyurethane fibers (spandex), glass fibers, carbon fibers, natural fibers (e.g., wool, cotton, cellulose nanofibers, etc.), Zylon (registered trademark), etc. Examples of the form of the fiber sheet 21 include nonwoven fabric, woven fabric, knitted fabric, etc. Examples of nonwoven fabric include spunlace nonwoven fabric, spunbond nonwoven fabric, and needle punch nonwoven fabric.

[0089] The fiber diameter of the fiber sheet 21 is preferably 2 to 10 denier (d), and more preferably 2 to 8 denier. The fiber sheet 21 has a basis weight of 70 to 500 g / m 2 It is preferable that the thickness is 90 to 500 g / m 2 When the fiber sheet 21 is made of fibers having a small fiber diameter in this manner, the distance between each of the fine fibers can be shortened to make the fibers dense, so that the raw material 11G of the polyurethane foam 11 is less likely to seep out from the fiber sheet 21 (skin material 20).

[0090] The fiber sheet 21 is made of a resin other than polyurethane resin, such as an acrylic ester resin such as ethyl acrylate, or a rubber resin such as styrene-butadiene rubber (SBR), at 35 to 100 g / m 2 It is preferable that the resin other than the polyurethane resin is adhered to the fiber sheet 21. By adhering the resin other than the polyurethane resin to the fiber sheet 21, the resin other than the polyurethane resin is interposed between the fibers, and the raw material 11G of the polyurethane foam 11 is less likely to pass through the fiber sheet 21 (skin material 20), and the raw material 11G is more unlikely to seep out. The resin other than the polyurethane resin may be adhered to the surface of the fiber sheet 21 or to the fibers inside the fiber sheet 21. For example, in the latter case, the polyurethane resin constituting the impregnation layer 22 may cover the resin other than the polyurethane resin adhered to the fibers. In order to adhere the resin other than the polyurethane resin to the fiber sheet 21, an emulsion may be applied to the surface of the fiber sheet 21, the fiber sheet 21 may be impregnated with the emulsion, or the surface of the fiber sheet 21 may be sprayed with powder and then exposed to a hot roller or hot air.

[0091] The air permeability of the impregnated layer 22 of the skin material 20 can be adjusted by adjusting the type of fiber constituting the fiber sheet 21, the fiber diameter, the basis weight, the amount of resin other than polyurethane-based resin, such as an acrylic ester-based resin, and the like.

[0092] The inner fiber sheet 21A is densely packed with fine fibers and is impregnated with an acrylic ester resin, so that the amount of impregnation (seeping) of the raw material 11G can be limited. This ensures the breathability of the skin material 20. On the other hand, the outer fiber sheet 21B has a fiber diameter larger than that of the inner fiber sheet 21A, for example, 5 denier or more, so that the wear resistance of the soundproofing material 10Y can be improved. In FIG. 8(A) and other figures, the impregnated layer 22 is shown in gray.

[0093] Next, a method for manufacturing the soundproofing material 10Y of this embodiment will be described. To manufacture the soundproofing material 10Y, first, raw material 11G (see FIG. 11(B)) of polyurethane foam 11 and skin material 20 are prepared. Specifically, raw material 11G of polyurethane foam 11 containing a polyol component, a polyisocyanate component, a foaming agent, a catalyst, etc. is prepared, and each skin material 20 (fiber sheets 21A, 21B are integrated by needle punching) is prepared.

[0094] As the raw material 11G of the polyurethane foam 11, the same materials as those exemplified as the raw material of the polyurethane foam 11 of the soundproofing material 10 of the first and second embodiments can be used.

[0095] Raw material 11G of polyurethane foam 11 is prepared in two parts: Liquid A, which is a mixture of a polyol component, a blowing agent, a catalyst, etc., and Liquid B, which contains a polyisocyanate component. If raw material 11G contains a foam stabilizer, this is mixed into Liquid A.

[0096] 11(A), a molding die 50 for molding the soundproofing material 10 comprises a lower die 51 and an upper die 52 which face each other with a cavity therebetween. For example, the skin material 20 is fixed to a molding surface 52M of the upper die 52. More specifically, at this time, the fiber sheet 21 which becomes the inner fiber sheet 21A is arranged so as to face the cavity side. Also, for example, only the inner fiber sheet 21A is impregnated in advance with an acrylic ester resin.

[0097] Next, as shown in Fig. 11(B), raw material 11G, in which liquids A and B are mixed, is injected into molding recess 51U of lower die 51, and then mold 50 is closed (see Fig. 12(A)), raw material 11G foams and hardens to form polyurethane foam 11 (see Fig. 12(B)). At this time, raw material 11G impregnates skin material 20 (specifically, inner fiber sheet 21A) and hardens to form impregnated layer 22, and polyurethane foam 11 and skin material 20 are bonded together.

[0098] The mold 50 is opened, and the integrated polyurethane foam 11 and skin material 20 are removed from the mold 50.

[0099] Next, the polyurethane foam 11 is appropriately cut, and then, as shown in Fig. 13, a piercing process is performed in which multiple needles 58 are pierced partway through the polyurethane foam 11. In this embodiment, the piercing process is performed using a stamper 57 on the open cell surface 11MA (exposed surface) of the polyurethane foam 11 opposite the skin material 20. This forms multiple piercing marks 18 extending from the open cell surface 11MA to the inside of the polyurethane foam 11. The piercing process may also be performed from the skin material 20 side (Fig. 14). In this case, it is possible to form piercing marks 18 that penetrate the skin material 20 and extend partway through the polyurethane foam 11.

[0100] 15, in the same manner as in the first embodiment, a blowing process is performed from the open cell surface 11MA of the polyurethane foam 11. As a result, the cell membrane 31 of the polyurethane foam 11 is broken to form breakage holes 32Y, thereby forming the sound absorbing structure 40.

[0101] As shown in FIG. 16, in this embodiment, the blowing process is also performed from the skin material 20 side integrated with the polyurethane foam 11. That is, compressed gas is blown into the polyurethane foam 11 from the outside of the skin material 20, the cell membrane 31 is broken, a broken hole 32Y is formed, a sound absorbing path 33 is added, and a sound absorbing structure 40 is formed (see FIG. 9). Also, as shown in FIG. 16, this blowing process is also performed by bringing the tip face of the nozzle N of the blow gun that ejects the compressed gas (i.e., the opening edge of the ejection port) into contact with the skin material 20. Note that the blowing process may be performed by bringing the nozzle N close to the skin material 20 (for example, by separating it by a distance of 2 mm or less). According to these methods, it becomes easy to blow the compressed gas into the polyurethane foam 11, and it becomes possible to suppress the variation in the amount of compressed gas blown in. Also, in this case, it is preferable that the dynamic pressure of the compressed gas to be blown in is 0.1 to 1.0 MPa. This makes it easy to form a sound absorbing path to the inside of the polyurethane foam 11. The blow treatment from the skin 20 side is also performed over the entire skin 20, but may be performed only on a part of the skin 20.

[0102] When the blowing process is finished, the soundproofing material 10Y shown in Fig. 8 is completed. Note that the blowing process does not have to be performed, or the blowing process may be performed from either the front or back side of the polyurethane foam 11.

[0103] The soundproofing material 10Y of this embodiment can also achieve the same effects as the soundproofing material 10 of the first and second embodiments. In this embodiment, one side of the polyurethane foam 11 is covered with the skin material 20, so that the soundproofing performance of the soundproofing material 10Y can be improved by the sound insulation effect or sound absorption effect of the skin material 20. In addition, by providing the skin material 20 with an impregnation layer, it is possible to improve the sound insulation performance of the soundproofing material 10Y and also to improve the rigidity of the soundproofing material 10Y. Furthermore, since the sound absorbing structure 40 is provided on both the side facing the skin material 20 and the opposite side of the polyurethane foam 11, it is possible to improve the sound absorption performance against sounds from both the front and back of the polyurethane foam 11.

[0104] 17, the soundproofing material 10Y of this embodiment can also be used in a soundproofing structure for a building or vehicle, and an example of such a soundproofing structure is a structure in which the soundproofing material 10Y is sandwiched between or spaced apart from a pair of sound insulating materials 71, 72, as in the first embodiment. In this way, a soundproofing structure in which the soundproofing material 10Y is disposed between a pair of sound insulating materials 71, 72 can improve sound absorption performance and sound insulating performance.

[0105] [Fourth embodiment] 18, soundproofing material 10W according to the second embodiment has a configuration in which polyurethane foam 11 is sandwiched between a pair of skin materials 20. Specifically, skin materials 20 are integrated with both the front and back surfaces of polyurethane foam 11.

[0106] In this embodiment, the polyurethane foam 11 has a sound absorbing structure 40 on both the front and back sides, similar to that on the skin material 20 side in the third embodiment. The front and back skin materials 20 have an impregnated layer 22 and are breathable. The polyurethane foam 11 and the skin material 20 may be made of the same material or have the same characteristics as those exemplified in the first embodiment. In this embodiment, the pair of skin materials 20 have the same configuration, but they may be different. In this case, for example, the impregnated layer 22 may be provided only on one of the skin materials 20. The impregnated layer 22 may not be provided on either of the skin materials 20.

[0107] The soundproofing material 10W of this embodiment is manufactured, for example, as follows. First, as shown in Figures 19 and 20, polyurethane foam 11 is formed in the same manner as in the second embodiment. In this embodiment, skin materials 20 are set on the molding surfaces of both upper and lower dies 52 and 51. At this time, the inner fiber sheets 21A of the pair of skin materials 20 are arranged so as to face each other and face the cavity side (Figure 19(A)).

[0108] Next, raw material 11G, in which liquids A and B are mixed, is injected into molding recess 51U of lower die 51 (19(B)), and mold 50 is closed (Fig. 20(A)), and raw material 11G foams and hardens to form polyurethane foam 11 (see Fig. 20(B)). At this time, raw material 11G impregnates a pair of skin materials 20 (more specifically, inner fiber sheet 21A) and hardens to form impregnated layer 22, and polyurethane foam 11 and a pair of skin materials 20 are bonded together.

[0109] Next, when the integrated polyurethane foam 11 and the skin material 20 are removed from the mold 50, a blowing process is performed. Specifically, in this embodiment, the polyurethane foam 11 is blown through the skin material 20 in the same manner as in the third embodiment, and this blowing process is performed from the front and back of the polyurethane foam 11. As a result, breakage holes 32Y are formed on the front and back of the polyurethane foam 11, and sound absorbing paths 33 are added, forming a sound absorbing structure 40. At this time, as shown in FIG. 21, this blowing process is also performed by bringing the tip surface of the nozzle N of the blow gun, which ejects compressed gas, into contact with the skin material 20, in the same manner as in the third embodiment. The blowing process may be performed by bringing the tip surface of the nozzle N close to the skin material 20, in the same manner as in the third embodiment.

[0110] In soundproofing material 10W of the present embodiment, sound absorbing structures 40 on the front and back of polyurethane foam 11 can improve the sound absorbing performance of polyurethane foam 11, thereby improving the soundproofing performance of soundproofing material 10W. In addition, since soundproofing material 10W has skin material 20 having impregnation layer 22 disposed on both the front and back of polyurethane foam 11, soundproofing material 10 can be made less prone to warping.

[0111] In this embodiment, the sound absorbing structure 40 may be provided on only one of the front and back sides of the polyurethane foam 11. Also, only one of the pair of skin materials 20 may be breathable. In this case, the other skin material 20 may be a fiber sheet that is made breathable by the impregnation layer 22, or may be a breathable resin film.

[0112] 22, the soundproofing material 10W of this embodiment can also be used in a soundproofing structure for a building or vehicle, and an example of such a soundproofing structure is a structure in which the soundproofing material 10W is sandwiched between or spaced apart from a pair of sound insulating materials 71, 72, as in the first embodiment. In this way, a soundproofing structure in which the soundproofing material 10W is disposed between a pair of sound insulating materials 71, 72 can improve sound absorption performance and sound insulating performance.

[0113] The piercing process may be performed on the inside of the polyurethane foam 11 through either one or both of the skins 20. In this case, the piercing process may be performed instead of the blowing process or may be performed before the blowing process.

[0114] [Fifth embodiment] As shown in Fig. 23, in the soundproofing material 10X according to the fourth embodiment, cuts are formed on one of the front and back surfaces (open cell surface 11MA) of the polyurethane foam 11 having a flat shape. Specifically, a plurality of linear cuts 15 are formed on one surface of the polyurethane foam 11, and parallel linear cuts 14 consisting of these linear cuts 15 intersect at right angles to each other to form a lattice-like cut 13. In this embodiment, each linear cut 15 is arranged parallel to one side of the polyurethane foam 11 and extends from one end of the polyurethane foam 11 to the other end. Moreover, the lattice-like cut 13 spreads over the entire one surface of the polyurethane foam 11.

[0115] The depth of the linear cuts 15 (i.e., the lattice-shaped cuts 13) may be up to the center in the thickness direction of the polyurethane foam 11, or may be up to a position close to one of the front and back surfaces of the polyurethane foam 11 or close to the other surface. For example, in this embodiment, the skin material 20 is integrated with the other surface of the polyurethane foam 11. In this case, the depth of the cut may be deep to the boundary of the polyurethane foam 11 with the skin material 20. Also, for example, when the polyurethane foam 11 is molded by molding, a skin layer is likely to be formed on the surface of the polyurethane foam 11. In this case, it is preferable to make the depth of the cut deeper than the skin layer of the polyurethane foam 11. This makes it easier to allow ventilation to a position deeper than the skin layer of the polyurethane foam 11. Note that the skin layer of the polyurethane foam 11 is preferably breathable, that is, the open cells 30A are preferably open on the surface, and such a skin layer can be easily formed by using a linear hydrocarbon wax as a release agent during foam molding of the polyurethane foam 11, as described in the first embodiment.

[0116] The soundproofing material 10X of this embodiment is manufactured, for example, as follows. First, in the same manner as in the second embodiment, the skin material 20 is integrally formed on the other of the front and back surfaces of the flat polyurethane foam 11. Next, lattice-shaped cuts 13 are made in one of the front and back surfaces (exposed surface) of the polyurethane foam 11. Specifically, the surface of the polyurethane foam 11 opposite the skin material 20 is placed on top, and a pressing die having a lattice-shaped cutter is pressed against that surface from above. As a result, the lattice-shaped cuts 13 are formed in the polyurethane foam 11.

[0117] Next, a blowing process is performed in which compressed gas is blown into the exposed surface of polyurethane foam 11. Since incisions 13 are formed on the exposed surface of polyurethane foam 11 as described above, compressed gas can be easily blown from a blow gun into polyurethane foam 11 through incisions 13, making it easier to form rupture holes 32Y. Since polyurethane foam 11 (particularly soft polyurethane foam) has high restorability, incisions 13 may close after being formed as described above. Even in this case, however, incisions 13 can be opened with compressed gas, making it easier to blow compressed gas into polyurethane foam 11 through incisions 13.

[0118] In this manner, the soundproofing material 10X is obtained. Note that in this embodiment, the blowing process does not necessarily have to be performed. Also, the piercing process may be performed into the polyurethane foam 11 from the skin 20 side or the side opposite to the skin 20. Also, the soundproofing material 10X may be composed of only the polyurethane foam 11 without providing the skin 20.

[0119] In this embodiment, by forming the cuts 13 in the polyurethane foam 11, sound (air) can easily enter the polyurethane foam 11, and the sound absorption properties of the inner part of the polyurethane foam 11 can be improved, and the sound insulation properties of the soundproofing material 10X can be improved. In addition, by providing the cuts 13 in the polyurethane foam 11, compressed gas can be blown into the polyurethane foam 11 through the cuts 13. This makes it easier to form the break holes 32Y, and the sound absorption properties of the polyurethane foam 11 can be further improved. In addition, by making such cuts to a position deeper than the skin layer in the polyurethane foam 11, it is possible to easily allow ventilation to a position deeper than the skin layer, and the sound absorption properties of the polyurethane foam 11 can be improved.

[0120] [Other embodiments] (1) The polyurethane foam 11 has a flat shape, but is not limited to this. For example, the polyurethane foam 11 may have a block shape such as a cube.

[0121] (2) In the above embodiment, the skin material 20 is integrated with the polyurethane foam 11 by foam molding of the polyurethane foam 11, but the skin material 20 may be laminated on the foam molded polyurethane foam 11 afterwards. In this case, the skin material 20 may be laminated on the surface of the polyurethane foam 11 that has been subjected to the blow treatment.

[0122] (3) The soundproofing material 10W of the third embodiment may be manufactured by a manufacturing line as described below. Specifically, the manufacturing line includes a conveying means (e.g., a conveyor) that conveys the long skin materials 20 in the longitudinal direction while they are arranged vertically facing each other. Then, raw material 11G of polyurethane foam 11 is discharged between the skin materials 20 while conveying the skin materials 20, and the raw material 11G is foamed and cured to form polyurethane foam 11. At this time, the raw material 11G of polyurethane foam 11 is impregnated into the pair of skin materials 20, and an impregnation layer 22 is formed in each of the skin materials 20. Thereafter, the skin materials 20 and the polyurethane foam 11 are cut to a predetermined length by a cutter to obtain the soundproofing material 10W. If the polyurethane foam 11 protrudes from the skin materials 20 at the end in the width direction of the soundproofing material 10W, the protruding portion is appropriately trimmed. Furthermore, if a heating furnace is provided in the middle of the conveying path of the conveying means, the foaming and curing of raw material 11G of polyurethane foam 11 is accelerated, and the moldability of soundproofing material 10 can be improved.

[0123] (4) The soundproofing material 10V of the second embodiment may be manufactured in the manufacturing line of the other embodiment (3) described above. In this case, only the lower skin material 20 of a pair of long skin materials 20 is transported in the manufacturing line of the other embodiment (3) described above in this embodiment, and raw material 11G of polyurethane foam 11 is discharged onto the lower skin material 20 and foamed and cured.

[0124] (5) In the second and third embodiments described above, when the covering material 20 is formed of the fiber sheet 21, the covering material 20 may be made of one fiber sheet 21 or three or more fiber sheets 21.

[0125] (6) In the second and third embodiments, the breathable covering material 20 may be a mesh-like material or may have a large number of holes passing through it.

[0126] (7) In the fourth embodiment, a piercing process may also be performed. When a blowing process is performed, the piercing process is preferably performed before the blowing process. Moreover, in the fifth embodiment, a cutting process may also be performed. When a blowing process is performed, the cutting process is preferably performed before the blowing process. EXAMPLES

[0127] The above embodiment will be described in more detail below with reference to examples and comparative examples, but the soundproofing material of the present invention is not limited to the following examples.

[0128] 1. Soundproofing material composition and manufacturing method In Examples 1 to 3 and Comparative Examples 1 and 2, as in the manufacturing method of the above-mentioned first embodiment, raw material 11G obtained by mixing liquid A and liquid B was reacted to foam-mold polyurethane foam 11 (semi-rigid polyurethane foam), and a soundproofing material consisting of polyurethane foam 11 alone was obtained. When foam-molded, polyurethane foam 11 had a size of 500 mm × 500 mm × 20 mm (thickness). In Examples 1 to 3 and Comparative Example 2, additional processing described below was performed on polyurethane foam 11 of that size. Examples 1 to 3 and Comparative Examples 1 and 2 differ from each other in the presence or absence of additional processing on polyurethane foam 11 or the type of additional processing, but raw material 11G of polyurethane foam 11 is the same.

[0129] In Example 4 and Comparative Examples 3 and 4, like the manufacturing method of the second embodiment described above, a raw material 11G in which a liquid A and a liquid B were mixed was reacted to foam-mold a polyurethane foam 11 (semi-rigid polyurethane foam), and a skin material 20 was integrated only on one side of the polyurethane foam 11, thereby obtaining a soundproof material having a size of 500 mm × 500 mm × 20 mm (thickness). Then, in Example 4 and Comparative Example 4, post-processing described below was performed on the soundproof material of that size. Incidentally, the thickness of the polyurethane foam 11 is 18 mm, and the thickness of the skin material 20 is 2 mm. In Example 4 and Comparative Examples 3 and 4, the presence or absence of post-processing on the polyurethane foam 11 or the type of post-processing is different from each other, and the raw material 11G of the polyurethane foam 11 and the skin material 20 are the same.

[0130] Incidentally, in Examples 1 to 4 and Comparative Examples 1 to 4, as the mold release agent during foam molding, a linear hydrocarbon wax "URM-520" manufactured by Konishi Co., Ltd. was used.

[0131] 1) Polyurethane foam In each example and each comparative example, the raw material 11G of the polyurethane foam 11 is the same. The details of the composition of the raw material 11G are as follows.

[0132] <Liquid A> Polyol 1; Polyether polyol (30 parts by weight, number average molecular weight: 5500, functional group number: 3.6, hydroxyl value: 31.5 mgKOH / g) Polyol 2; Polymer polyol (70 parts by weight, number average molecular weight: 5000, functional group number: 3, hydroxyl value 25 mgKOH / g, solid content concentration: 30%) Blowing agent; Water (4.35 parts by weight) Amine catalyst 1; "Diethanolamine" manufactured by Showa Chemical Co., Ltd. (2.50 parts by weight) Amine catalyst 2; "DABCO BL-11" manufactured by Evonik Japan Co., Ltd. (0.37 parts by weight) Foam stabilizer; "TEGOSTAB B8715LF2" manufactured by Evonik Japan Co., Ltd. (0.50 parts by weight) Additive; Polyether polyol (1.85 parts by weight, number average molecular weight: 5000, number of functional groups: 3, hydroxyl value 34 mg KOH / g) <Liquid B> Polyisocyanate; Polymeric MDI (NCO value 31.5%)

[0133] Note that the isocyanate index was set to 105. The isocyanate index is a value obtained by multiplying the value obtained by dividing the number of moles of isocyanate groups in the polyisocyanate by the number of moles of all active hydrogen groups such as polyol and blowing agent (water) by 100.

[0134] 2) Skin material In Example 4 and Comparative Examples 3 and 4, the skin material 20 was configured as a two-layer structure of fiber sheets 21, 21 (inner fiber sheet 21A and outer fiber sheet 21B). The inner fiber sheet 21A is made of PET fibers with a fiber diameter of 3 denier, and the basis weight is 100 g / m 2 is. The outer fiber sheet 21B is made of PET fibers with a fiber diameter of 6 denier, and the basis weight is 150 g / m 2 is. In the skin material 20, only the inner fiber sheet 21A is impregnated with an acrylate resin, and the impregnation amount is 50 g / m 2 is.

[0135] 3) Types of additional processing The details of the additional processing performed when manufacturing the sound insulation materials of the examples and comparative examples are as follows.

[0136] (1) Piercing treatment In the piercing process, similarly to the fifth embodiment, the needle 58 was pierced into a plurality of places in the soundproofing material to form a plurality of piercing marks 18 extending halfway through the polyurethane foam 11 in the thickness direction. In detail, the needle 58 is composed of a cylindrical body portion which is the base end side, and a triangular pyramid-shaped tip portion. The diameter of the body portion of the needle 58 is 1.35 mm, and the axial length of the body portion is 9 mm. The axial length of the tip portion of the needle 58 is 4 mm. The piercing marks 18 of the needle 58 are arranged in a square lattice pattern, and the lattice interval (the interval between the central axes of adjacent needles 58) is 3.65 mm. The piercing depth of the needle 58 into the soundproofing material is 4.0 mm.

[0137] (2) Cutting In the cut processing, in the same manner as in the fourth embodiment, lattice-shaped cuts 13 are formed on the surface to be cut of the front and back of the soundproofing material. The cuts 13 are made of a plurality of parallel linear cuts 15 groups that intersect at right angles. The distance between the linear cuts 15 is 5 to 150 mm. The depth of the cuts 13 into the soundproofing material is 3.0 to 5.0 mm.

[0138] (3) Roll crushing In the roll crushing, the polyurethane foam 11 was conveyed and passed between a pair of rotating rolls to crush the entire polyurethane foam 11. The axial length of the rotating rolls was longer than 500 mm, the diameter of the rotating rolls was 200 mm, the clearance between the pair of rotating rolls was 9 mm, and the conveying speed of the polyurethane foam 11 was 70.5 mm / sec. In Comparative Examples 2 and 4, the roll crushing was performed eight times (i.e., the polyurethane foam 11 was passed between the pair of rotating rolls eight times). In detail, the roll crushing was performed once in each of four arrangements (i.e., arrangements rotated by 90 degrees) in which each side of the polyurethane foam 11 was parallel to the rotating rollers and at the front of the conveying direction, a total of four times. Furthermore, the polyurethane foam 11 was turned over and then similar roll crushing was performed a total of four times.

[0139] 4) Details of additional processing in each embodiment and comparative example Details of the additional processing in each embodiment and each comparative example are as follows. Note that, hereinafter and in Figures 23 and 24, either the front or back surface of the soundproofing material will be referred to as the first surface, and the other surface will be referred to as the second surface. Note that the first surface will be the upper surface when measuring the reverberation room sound absorption coefficient described later.

[0140] <Example 1> Only the piercing process was performed on both the first and second surfaces (both the front and back). <Example 2> The first surface was only subjected to the piercing process, and the second surface was only subjected to the cutting process. <Example 3> Only piercing was performed on the first surface, and no additional processing was performed on the second surface. <Example 4> Only piercing was performed on both the first and second surfaces. <Comparative Examples 1 and 3> No additional processing has been performed on the soundproofing material, and therefore no breakage hole 32Y has been formed. <Comparative Examples 2 and 4> Only roll crushing was performed.

[0141] 2. Evaluation For each of the examples and comparative examples, the appearance, closed cell ratio, hardness, reverberation room sound absorption coefficient, transmission loss, etc. were evaluated. The measurement methods for the measurement items are as follows.

[0142] <Measurement method> (1) Density The apparent density of the polyurethane foam 11 was measured based on JIS K7222: 2005. Specifically, a test piece of 500 mm×500 mm×20 mm (thickness) was cut into a piece of 100 mm×100 mm×20 mm (thickness) and the measurement was performed.

[0143] (2) Airflow rate The airflow rate was measured based on JIS K6400-7 B method: 2012. Specifically, the airflow rate was measured by passing air from the bottom to the top of three slice samples (100 mm square) obtained by slicing the soundproofing material so as to divide it in the thickness direction. In detail, when the soundproofing material is made only of polyurethane foam 11, a first surface side slice sample including the first surface, a second surface side slice sample including the second surface, and a central slice sample which is the central part in the thickness direction were prepared to have a thickness of 4 mm, and the first surface side slice sample was arranged so that the first surface was facing down, and the second surface side slice sample and the central slice sample were arranged so that the second surface side was facing down. In addition, when the soundproofing material has a skin material 20 on one side (first surface), a central slice sample (thickness 4 mm) which is the central part in the thickness direction of polyurethane foam 11, a second surface side slice sample (thickness 4 mm) including the second surface (exposed surface), and a slice sample consisting of only the skin material 20 on the first surface side were prepared. The central slice sample and the second surface side slice sample of polyurethane foam 11 were ventilated from the second surface side (placed with the second surface side on the bottom), and the latter slice sample (skin material 20) was ventilated from the impregnated layer 22 side (placed with the impregnated layer 22 side on the bottom) and measured.

[0144] (3) Closed cell ratio A scanning electron microscope (SEM: manufactured by JEOL Ltd.) was used to observe a region of a predetermined area (center region D and surface region S in FIG. 2) in the center and surface layer portion 10S of the outer peripheral surface 11E of the polyurethane foam 11, and the number of closed cells 30B in the predetermined area was counted. The ratio of the number of closed cells 30B in the surface region S to the number of closed cells 30B in the center region D was defined as the closed cell ratio. The center region D was determined so that the center position 10D in the thickness direction of the polyurethane foam 11 was the center of the center region D, and the surface region S was determined so that it was within a range of 3 mm deep from the surface in the thickness direction of the polyurethane foam 11. The predetermined area observed by the SEM in the center region D and surface region S was 2.5×2.5 mm. A low closed cell ratio means that the number of closed cells is smaller on the surface side than inside the polyurethane foam 11. The magnification of the SEM was 35 times.

[0145] The closed cell ratio was evaluated as follows: ⊚ when it was 0.7 or less, ◯ when it was more than 0.7 and less than 1.0, and × when it was more than 1.0.

[0146] (4) Cell diameter A scanning electron microscope (SEM: manufactured by JEOL Ltd.) was used to measure the average major axis and the average minor axis of the five foam cells, including the largest foam cell 30, the smallest foam cell 30, and any three other foam cells 30, in an enlarged image of the central portion (central region D (see FIG. 2)) in the thickness direction of the outer peripheral surface 11E of the polyurethane foam 11. The ratio of the average major axis to the average minor axis (major axis / minor axis) was calculated from the average major axis and the average minor axis of the five foam cells, including the largest foam cell 30, the smallest foam cell 30, and any three other foam cells 30. The major axis of the foam cell 30 is the length of the longest part of each foam cell 30 observed by SEM, and the minor axis of the foam cell 30 is the length of the shortest part of each foam cell 30 observed by SEM. The magnification of the SEM was 35 times.

[0147] The foam cells 30 were evaluated as having a major axis / minor axis ratio of 1 or more and 1.5 or less as ⊚ and as x when the ratio was more than 1.5.

[0148] (5) Deformation due to additional processing The deformation of the soundproofing material was confirmed before and after the additional processing. Specifically, the thickness of the test piece was measured before and after the additional processing, and the change was confirmed. The thickness of the test piece was measured at three points (both ends and the center) on each of the four sides of the test piece, and the average thickness of these 12 points was used.

[0149] The thickness of the soundproofing material after the additional processing was evaluated as follows: ◎ if it was 19 mm or more, ○ if it was 18 mm or more but less than 19 mm, and × if it was less than 18 mm. As mentioned above, the thickness of the soundproofing material before the additional processing was 20 mm.

[0150] (6) Hardness The hardness of the polyurethane foam 11 was measured based on JIS K6400-2 E method:2012. Specifically, a test piece of 500 mm x 500 mm x 20 mm was cut to 200 mm x 200 mm x 20 mm, and the test piece was compressed from above with a compression tool (the pressing surface was a circle with a diameter of 80 mm) at a compression speed of 50 mm / min until the deformation in the thickness direction was 80% of the original thickness of the test piece, and the load at 50% compression (50% compression hardness) was measured. The soundproofing material was arranged so that the first surface faced upward.

[0151] The 50% compression hardness was evaluated as ⊚ when it was 500N or more, and as x when it was less than 500N.

[0152] (7) Transmission loss Transmission loss was measured based on JIS A1441-1:2007. Specifically, the test piece was placed on an iron plate (500mm x 500mm x 0.8mm (thickness)), and a rubber plate (500mm x 500mm x 1.0mm (thickness)) was placed on top of that to prepare a measurement sample. The soundproofing material was placed so that the first surface faced upwards.

[0153] The transmission loss was evaluated as follows: ⊚ when it was 50 dB or more, ◯ when it was 48 dB or more and less than 50 dB, and × when it was less than 48 dB.

[0154] (8) Reverberation room sound absorption coefficient Based on JIS A1409:1998, the reverberation room sound absorption coefficient of the test piece of the soundproofing material was measured. Specifically, four test pieces measuring 500mm x 500mm x 20mm (thickness) were laid on the floor of the reverberation room to form a measurement sample measuring 1m x 1m x 20mm, and the reverberation room sound absorption coefficient at each frequency was measured. At this time, the outer circumference of the measurement sample was covered with an aluminum fixture, and the test pieces and the gaps between the test pieces and the fixture were sealed with aluminum tape. Then, the sound absorption coefficients at frequencies of 500, 630, 800, 1000, 1250, 1600, 2000, 2500, 3150, 4000, 5000, and 6300Hz were measured both with the first surface facing upward and with the second surface facing upward, and the average value of all the measured values ​​was taken as the reverberation room sound absorption coefficient of the test piece.

[0155] The reverberation room sound absorption coefficient was evaluated as follows: 0.50 or more, 0.45 or more and less than 0.50, ○, and less than 0.45, ×.

[0156] If all of the above evaluation items were scored as ○ or above and there were three or more ◎ marks, the overall evaluation was given as "◎". If all of the evaluation items were scored as ○ or above and there were two or fewer ◎ marks, the overall evaluation was given as "○". If there was even one × mark, the overall evaluation was given as "×".

[0157] <Evaluation Results> As shown in Figures 24 and 25, it was confirmed that in Examples 1 to 4, in which piercing processing was performed as additional processing, the reverberation chamber sound absorption coefficient was significantly improved compared to Comparative Examples 1 and 3, in which additional processing was not performed (rating of ◯ or higher). In Examples 1 to 4, the transmission loss was also better than in Comparative Examples 1 and 3 (rating of ◯ or higher). Also, as can be seen from the comparison between Example 1 and Example 3, it was found that the improvement in the reverberation chamber sound absorption coefficient was greater when piercing processing was performed from both sides of the soundproofing material than when piercing was performed from only one side.

[0158] In addition, in Comparative Examples 2 and 4 in which roll crushing was performed as additional processing, the reverberation chamber sound absorption coefficient and transmission loss were improved compared to Comparative Examples 1 and 3 in which no additional processing was performed, but the deformation of the polyurethane foam 11 due to roll crushing was large. Specifically, the polyurethane foam 11 was crushed by roll crushing, and the thickness of the polyurethane foam 11 became thinner (see thickness after additional processing). In addition, in Comparative Examples 2 and 4, as can be seen from a comparison of the 50% compression hardness with Comparative Examples 1 and 3, it is hardened. Therefore, it can be seen that when roll crushing is performed, the soundproofing material is difficult to restore and the dimensional accuracy is reduced. In addition, as can be seen from the major axis / minor axis ratio of the cell diameter, in Comparative Examples 2 and 4, the foam cells 30 are longer than in Examples 1 to 4 and Comparative Examples 1 and 3. This is considered to be because the foam cells 30 are crushed by roll crushing.

[0159] In contrast, in Examples 1 to 4 in which piercing was performed without roll crushing, no deformation of the polyurethane foam 11 was observed, and the hardness of the polyurethane foam 11 was also almost the same as in Comparative Examples 1 and 3 in which no additional processing was performed (both the thickness after additional processing and the 50% compression hardness were rated as ⊚). Thus, it was found that the soundproofing materials of Examples 1 to 4 can improve sound absorption while preventing deterioration of dimensional accuracy due to additional processing.

[0160] As described above, it was confirmed that the soundproofing materials of Examples 1 to 4, which were subjected to the piercing treatment, are capable of improving sound absorption properties while preventing a decrease in dimensional accuracy, compared to the soundproofing materials of Comparative Examples 1 to 4 (overall evaluation of ○ or higher). [Explanation of symbols]

[0161] 10. Soundproofing materials 11 Polyurethane foam 13 Cutting 18 Stab wounds 30 Foam Cell 30A open cell 30B Closed Cell 31 Cell Membrane 32 cell holes 32X foam hole 32Y Break Hole 33 Sound absorption path

Claims

1. A method for producing a soundproofing material including a sound-absorbing polyurethane foam, comprising the steps of: a piercing process in which a tip of a needle or a blade is pierced halfway through the foamed polyurethane foam at multiple locations; and a blowing treatment for blowing compressed gas into the polyurethane foam to form fracture holes.

2. The piercing process is carried out from one side of the polyurethane foam, The method for producing a soundproofing material according to claim 1 , further comprising the step of: forming cuts in a surface of the polyurethane foam opposite to the one side surface.

3. The polyurethane foam is molded by molding, and a high-density layer having an apparent density higher than that of an inner portion of the polyurethane foam is formed as a surface layer of the polyurethane foam onto which the compressed gas is blown in the blowing treatment; The method for producing a soundproofing material according to claim 2 , wherein the incisions are made deeper than the high density layer formed in the polyurethane foam in the incision process.

4. 4. The method for producing a soundproofing material according to claim 1, wherein a straight-chain hydrocarbon wax is used as a release agent during foam molding of the polyurethane foam.

5. A soundproofing material comprising a sound-absorbing polyurethane foam, A plurality of puncture marks caused by the tip of a needle or blade extending halfway through the polyurethane foam; A soundproofing material comprising a surface material integrated on both sides of the polyurethane foam and containing a fiber aggregate.

6. 6. The soundproofing material according to claim 5, further comprising an impregnation layer formed on the skin material and impregnated with a raw material of the polyurethane foam and cured.

7. The soundproofing material according to claim 6 , wherein the puncture marks penetrate the impregnated layer.

8. 8. The soundproofing material according to claim 5, having a plurality of puncture marks made by the tip of a needle or blade extending from opposite sides of the polyurethane foam to partway through the polyurethane foam.

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