Soundproofing materials

Abstract

To provide a soundproof material capable of improving soundproof performance and a method for producing the same.SOLUTION: A soundproof material 10 includes a polyurethane foam 11 for sound absorption. The soundproof material 10 is made by integrating a breathable surface material on a surface of the polyurethane foam, and then blowing compressed gas from the surface of the foam-molded polyurethane foam 11 through the surface material into an interior to a cell membrane 31 of a plurality of foam cells 30 in the polyurethane foam 11 by a blowing process. The soundproof material is manufactured by additionally processing 32Y of fracture holes.SELECTED DRAWING: Figure 17

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 producing a soundproofing material containing polyurethane foam, comprising: integrating the polyurethane foam with a pair of breathable skin materials such that the polyurethane foam is sandwiched between the pair of skin materials; and performing a blowing process in which compressed gas is blown into the foam-molded polyurethane foam through the skin materials, thereby additionally drilling rupture holes in cell membranes of a plurality of foam cells contained in the polyurethane foam.

[0006] A second aspect of the invention is the method for producing a soundproofing material according to the first aspect, wherein the blowing treatment is carried out by bringing a tip face of a nozzle that ejects the compressed gas into contact with or close to a surface of the skin material.

[0007] A third aspect of the invention is the method for producing a soundproofing material according to the second aspect, wherein the dynamic pressure of the compressed gas is 0.1 to 1 MPa.

[0008] A fourth aspect of the invention is a method for producing a soundproofing material as defined in any one of the first to third aspects, further comprising a piercing process in which tips of a plurality of needles or blades are pierced through the skin material into a surface of the polyurethane foam prior to the blowing process.

[0009] A fifth aspect of the invention is a soundproofing material comprising a polyurethane foam, the polyurethane foam and a pair of breathable skin materials being integrated together such that the polyurethane foam is sandwiched between the pair of skin materials, the soundproofing material has rupture holes formed in cell membranes of a plurality of foam cells contained in the polyurethane foam, and the number of closed cells among the foam cells is fewer toward the surface with which the skin materials are integrated than toward the interior of the polyurethane foam.

[0010] A sixth aspect of the invention is a soundproofing material comprising a polyurethane foam, the polyurethane foam and a pair of breathable skin materials being integrated together such that the polyurethane foam is sandwiched between the pair of breathable skin materials, the soundproofing material has rupture holes formed in cell membranes of a plurality of foamed cells contained in the polyurethane foam, and the air permeability of the polyurethane foam is greater closer to the surface with which the skin materials are integrated than to the interior of the polyurethane foam.

[0011] A seventh aspect of the invention is the soundproofing material according to the fifth or sixth aspect, wherein the polyurethane foam has a flat shape, the skin material is integrated on both its front and back sides, and the ratio of the number of closed cells per unit cross-sectional area in the central part in the thickness direction of the polyurethane foam to the number of closed cells per unit cross-sectional area in the surface layer parts extending to a depth of 3 mm from both the front and back sides of the polyurethane foam is 0.7 or less.

[0012] An eighth aspect of the invention is the soundproofing material according to any one of the fifth to seventh aspects, wherein the ratio of the number of open cells to the total number of foamed cells is greater nearer the surface where the skin material is integrated than nearer the interior of the polyurethane foam.

[0013] A ninth aspect of the invention is the soundproofing material according to any one of the fifth to eighth aspects, wherein the rupture holes are formed by rupturing the cell membrane due to the wind pressure of compressed gas blown into the inside of the polyurethane foam through the skin material.

[0014] A tenth aspect of the invention is the soundproofing material according to any one of the fifth to ninth 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

[0015] In a first aspect of the invention, a polyurethane foam is integrated with a pair of breathable skin materials so that the polyurethane foam is sandwiched between them. A blowing process is then performed through the skin materials to blow compressed gas into the polyurethane foam, and rupture holes are additionally formed in the cell membrane of the multiple foam cells. This makes it easier for the foam cells on the surface side of the polyurethane foam to communicate with each other, 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 while protecting it with the skin materials, and to improve the soundproofing performance of the soundproofing material.

[0016] In the second aspect of the invention, the blowing process is performed by bringing the tip of the nozzle for ejecting the compressed gas into contact with or close to the surface of the skin material. This makes it easier to blow the compressed gas into the polyurethane foam and also makes it possible to suppress variation in the amount of compressed gas blown in. In this case, by setting the dynamic pressure of the compressed gas to 0.1 to 1 MPa (third aspect of the invention), it becomes easier to form rupture holes extending to the inside of the polyurethane foam.

[0017] In the fourth aspect of the invention, the tip of a needle or blade is pierced through the skin material into the surface of the polyurethane foam prior to the blowing process, making it easier to blow compressed gas into the interior of the polyurethane foam through the piercing mark.

[0018] In the soundproofing material of the fifth aspect of the invention, the polyurethane foam and a pair of skin materials having air permeability are integrated so that the polyurethane foam is sandwiched between the pair of skin materials. The soundproofing material has foaming holes formed in the cell membrane during foaming of the polyurethane foam, and the number of closed cells among the foam cells is smaller near the surface where the skin materials are integrated than inside the polyurethane foam. This makes it possible to increase the number of open cells that are connected by rupture holes or the like near the surface of the polyurethane foam than inside. In the soundproofing material of the sixth aspect of the invention, the air permeability of the polyurethane foam is larger near the surface where the skin materials are integrated than inside the polyurethane foam. These configurations make it possible to increase the air permeability of the surface side of the polyurethane foam, and to increase the sound absorption performance of the polyurethane foam from the surface side, which results in improved soundproofing performance of the soundproofing material.

[0019] In a seventh aspect of the invention, the polyurethane foam has a flat shape and is integrated with skin materials on both sides thereof, and the ratio of the number of closed cells per unit cross-sectional area in the central part in the thickness direction of the polyurethane foam to the number of closed cells per unit cross-sectional area in the surface layer parts up to a depth of 3 mm from both sides of the polyurethane foam is 0.7 or less. With this configuration, it is possible to particularly improve the sound absorption performance of the polyurethane foam.

[0020] In an eighth aspect of the invention, the ratio of the number of open cells to the total number of foam cells is higher closer to the surface where the skin material is integrated than to the inside of the polyurethane foam. This configuration improves the breathability 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 absorption performance of the polyurethane foam.

[0021] As in the ninth aspect of the invention, the rupture holes in the polyurethane foam can be easily formed by rupturing the cell membranes with the wind pressure of compressed gas blown into the polyurethane foam through the skin material.

[0022] In the tenth 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, if a break hole is formed in the cell membrane by, for example, roll crushing, the polyurethane foam is crushed and does not recover, so that the dimensional accuracy is reduced and wrinkles are generated, which tends to deteriorate the appearance. However, in the configuration of the present invention, roll crushing is not necessary, so that it is possible to suppress the deterioration of the dimensional accuracy and the deterioration of the appearance of the polyurethane foam. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a cross-sectional side view of a soundproofing material according to a first embodiment. [Diagram 2] Enlarged cross-sectional side view of polyurethane foam soundproofing material [Diagram 3] Enlarged cross-sectional side view of polyurethane foam cells [Figure 4] Side cross-sectional view of soundproofing material undergoing blow treatment [Diagram 5] Side cross-sectional view showing an example of soundproofing material use [Figure 6] 10 is a cross-sectional side view of a soundproofing material according to a second embodiment. [Figure 7] Enlarged cross-sectional side view of polyurethane foam soundproofing material [Figure 8] Enlarged cross-sectional side view of polyurethane foam cells [Figure 9] (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 10](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 11] Side cross-sectional view of soundproofing material with polyurethane foam surface being blown [Figure 12] A cross-sectional side view of a soundproofing material being blown from the skin side. [Figure 13] Side cross-sectional view showing an example of soundproofing material use [Figure 14] 11 is a cross-sectional side view of a soundproofing material according to a third embodiment. [Figure 15] (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 16] (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 17] A cross-sectional side view of a soundproofing material being blown from the skin side. [Figure 18] Side cross-sectional view showing an example of soundproofing material use [Figure 19] 13 is a perspective view of a soundproofing material according to a fourth embodiment. [Figure 20] FIG. 5 is a cross-sectional side view of a soundproofing material according to a fifth embodiment; [Figure 21] Side cross-sectional view of polyurethane foam being pierced from the exposed side [Figure 22] A cross-sectional side view of a polyurethane foam being pierced from the skin side. [Figure 23] Enlarged image of foam cells on the outer surface of polyurethane foam [Figure 24] Table showing examples and comparative examples DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] [First embodiment] As shown in Fig. 1, 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.

[0025] 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.

[0026] 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 When the density is 60 kg / m or more, the sound insulation of the polyurethane foam 11 is particularly improved, 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.

[0027] As shown in FIG. 3, 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.

[0028] As shown in FIG. 1 and FIG. 2, polyurethane foam 11 has sound absorbing structure 40 including sound absorbing surface 11M for allowing sound (air) to enter polyurethane foam 11 and sound absorbing path 33 communicating from sound absorbing surface 11M to the inside of polyurethane foam 11. In detail, as shown in FIG. 3, sound absorbing surface 11M is a surface of polyurethane foam 11 where open cells 30A of foam cells 30 are open. Also, sound absorbing path 33 is formed by a plurality of open cells 30A communicating from sound absorbing surface 11M to the inside of polyurethane foam 11. Note that a skin layer may not be formed on sound absorbing surface 11M of polyurethane foam 11, or a skin layer having air permeability may be formed. Here, in the present disclosure, the skin layer refers to a surface layer having a higher apparent density than the inner part of polyurethane foam 11, for example, a part from the surface of polyurethane foam 11 to a depth of 0.5 to 1 mm. For example, in FIG. 23, the polyurethane foam 11 is shown with its surface facing up, with the skin layer designated by the numeral 16 .

[0029] Here, the above-mentioned cell holes 32 include foam holes 32X formed during foam molding of the polyurethane foam 11, and break holes 32Y formed by breaking the cell membrane 31 after foam molding. Specifically, as described later, the break holes 32Y are formed by breaking the cell membrane 31 due to the wind pressure of compressed gas blown into the polyurethane foam 11 from the surface (sound absorbing surface 11M) thereof. For example, the broken cell membrane 31 may be attached to the opening edge of the break holes 32Y.

[0030] 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 rupture holes Y, is larger closer to the sound absorbing surface 11M than to the inside of the polyurethane foam. Also, 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 increased, and it is possible to improve the sound absorbing performance of the polyurethane foam 11 (i.e., the soundproofing material 10) against sound from the sound absorbing surface 11M side. Also, since the air permeability of the inside of the polyurethane foam 11 is lower than that of the part on the sound absorbing surface 11M side, it is possible to improve the sound insulation of the polyurethane foam 11. The above-mentioned comparison of the total opening area can be carried out, 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. 2) 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 planar total area of ​​the cell holes 32 in a predetermined region of the cut surface in any direction, and compare them at different depths. The air permeability of the polyurethane foam 11 can be compared, for example, by dividing the polyurethane foam 11 into three equal parts in the thickness direction, and measuring the air permeability (based on JIS K6400-7 B method: 2012) between the central part in the thickness direction and the part on the sound absorbing surface 11M side.

[0031] 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 per unit cross-sectional area 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. 2) 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 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 of the polyurethane foam 11 and a central region D of a predetermined area including the central position 10D (see FIG. 2). 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.

[0032] 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 portion of the foam cells 30, and the minor axis is the length of the smallest portion 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. The 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. 2).

[0033] 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.

[0034] 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, the light becomes more difficult to shine from the center in the thickness direction toward the front and back sound absorbing surfaces 11M. In this embodiment, the surface layer portion 10S constituting 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] After molding, the polyurethane foam 11 is appropriately cut and then subjected to a blowing process as shown in Fig. 4. In the blowing process, compressed gas is blown into the polyurethane foam 11 to break the cell membranes 31 of the foam cells 30 of the polyurethane foam 11, thereby forming breakage holes 32Y.

[0039] 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. 4, 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.

[0040] 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.

[0041] 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.

[0042] In addition, before the blowing process, a piercing process may be performed in which the tips of multiple needles or blades are pierced into the open cell surface 11MA of the polyurethane foam 11. This makes it possible to easily blow compressed gas into the interior of the polyurethane foam 11 through the perforations formed by the piercing process. In addition, before the blowing process, a cutting process may be performed in which cuts are made in the sound absorbing surface 11M with a cutter. This process also makes it possible to easily blow compressed gas into the interior of the polyurethane foam 11 through the cuts. These piercing and cutting processes are particularly effective when blowing 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 possible to easily blow compressed gas into the interior of the polyurethane foam 11. When 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.

[0043] When the above-mentioned blowing process is completed, the soundproofing material 10 shown in Fig. 1 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 increases and the total opening area of ​​the cell holes 32 increases the closer to the surface from the inside.

[0044] The details of the raw materials for polyurethane foam 11 are as follows:

[0045] 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.

[0046] 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).

[0047] 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.

[0048] 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.

[0049] 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.

[0050] The raw material 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 the raw material of polyurethane foam 11 contains a foam stabilizer, this is mixed into Liquid A.

[0051] 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 form rupture holes 32Y in the cell membrane 31 of the plurality of foamed cells 30, and a sound absorbing path 33 is added that communicates from the sound absorbing surface 11M to the inside of the polyurethane foam 11. This improves the sound absorbing performance of the polyurethane foam 11, and makes it possible to improve the sound absorbing performance of the soundproofing material 10.

[0052] In this embodiment, the cell membranes are broken by the wind pressure of the compressed gas during the blowing process, so that the breakage holes 32Y in the polyurethane foam 11 can be easily formed.

[0053] 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.

[0054] 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.

[0055] 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 thickness direction of the polyurethane foam 11 is 0.7 or less, it is possible to particularly improve the sound absorption performance of the polyurethane foam 11.

[0056] 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 rupture hole 32Y is formed in the cell membrane 31 by, for example, roll crushing, the polyurethane foam 11 is crushed and does not recover, so that the dimensional accuracy is reduced and wrinkles are generated, which tends to deteriorate the appearance. However, according to the present embodiment, roll crushing is not necessary, so that it is possible to suppress the deterioration of the dimensional accuracy of the polyurethane foam 11 and the deterioration of the appearance.

[0057] In the soundproofing material 10 of this embodiment, the sound absorbing surface 11M and the sound absorbing path 33 are arranged on both sides in the thickness direction of the flattened polyurethane foam 11, thereby improving the sound absorption performance of the sound from both sides.

[0058] FIG. 5 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-like 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.

[0059] [Second embodiment] As shown in Fig. 6, soundproofing material 10V according to the second embodiment has a skin material 20 integrated with a part of the surface of polyurethane foam 11. In soundproofing material 10V of this embodiment, polyurethane foam 11 has a flat shape, and skin material 20 is integrated only on one of the front and back surfaces. Note that examples of flat shapes include plate-like and other flat shapes, and flat shapes also include shapes with irregularities formed on the front or back surface. In this embodiment, polyurethane foam 11 has a flat plate shape.

[0060] 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.

[0061] 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.

[0062] The polyurethane foam 11 of the soundproofing material 10V of this embodiment has a foam 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 first embodiment. Specifically, this foam structure is provided on both sides of the polyurethane foam 11, the front and rear sides 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. 6) of the polyurethane foam 11 has the same closed cell ratio as the first embodiment, but 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. 8) per unit cross-sectional area in the surface portion 10S (FIG. 7) from the sound absorbing surface 11M to a depth of 3 mm to the number of closed cells 30B (FIG. 8) per unit cross-sectional area in the central portion in the thickness direction of polyurethane foam 11 (i.e., the portion including central position 10D (FIG. 7) at a depth of 10 mm from the sound absorbing surface 11M covered by skin material 20). 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.

[0063] 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.

[0064] 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).

[0065] 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.

[0066] 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.

[0067] 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 abrasion resistance of the soundproofing material 10V can be improved. In FIG. 6 and other figures, the impregnated layer 22 is shown in gray.

[0068] Next, a method for manufacturing the soundproofing material 10V of this embodiment will be described. To manufacture the soundproofing material 10V, first, raw material 11G (see FIG. 9(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.

[0069] 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 embodiment can be used.

[0070] 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.

[0071] 9(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.

[0072] Next, as shown in Fig. 9(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. 10(A)), and raw material 11G is foamed and cured to form polyurethane foam 11 (see Fig. 10(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.

[0073] The mold 50 is opened, and the integrated polyurethane foam 11 and skin material 20 are removed from the mold 50.

[0074] Next, the polyurethane foam 11 is appropriately cut, and then, as shown in Fig. 11, a blowing process is performed from the open cell surface 11MA of the polyurethane foam 11 in the same manner as in the first embodiment. As a result, the cell membrane 31 of the polyurethane foam 11 is broken to form breakage holes 32Y, and the sound absorbing structure 40 is formed.

[0075] As shown in FIG. 12, 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, and the cell membrane 31 is broken to form a broken hole 32Y, and the sound absorbing path 33 is added, and the sound absorbing structure 40 is formed. Also, as shown in FIG. 12, 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.

[0076] Once the blowing process is complete, the soundproofing material 10V shown in Figure 6 is completed.

[0077] The soundproofing material 10V of this embodiment can achieve the same effect as the soundproofing material 10 of the first embodiment. 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 10V can be improved by the sound insulation effect or sound absorption effect of the skin material 20. In addition, the impregnation layer is provided on the skin material 20, so that the sound insulation performance of the soundproofing material 10V can be improved and the rigidity of the soundproofing material 10V can be improved. Furthermore, 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, so that the sound absorbing performance against the sound from both the front and back of the polyurethane foam 11 can be improved.

[0078] 13, the soundproofing material 10V 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 10V 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 10V is disposed between a pair of sound insulating materials 71, 72 can improve sound absorption performance and sound insulating performance.

[0079] [Third embodiment] 14, 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.

[0080] 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 second 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 and second embodiments. In this embodiment, the pair of skin materials 20 have the same configuration, but 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.

[0081] The soundproofing material 10W of this embodiment is manufactured, for example, as follows. First, as shown in Figures 15 and 16, 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 15(A)).

[0082] Next, raw material 11G, in which liquids A and B are mixed, is injected into molding recess 51U of lower die 51 (15(B)), and then mold 50 is closed (FIG. 16(A)), and raw material 11G foams and hardens to form polyurethane foam 11 (see FIG. 16(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.

[0083] 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 second embodiment, and this blowing process is performed from the front and back of the polyurethane foam 11. As a result, rupture 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. 17, 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 second 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 second embodiment.

[0084] 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.

[0085] 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.

[0086] 18, 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.

[0087] [Fourth embodiment] As shown in Fig. 19, 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] In this manner, the soundproofing material 10X is obtained. In this embodiment, the blowing process does not necessarily have to be performed. Also, the soundproofing material 10X may be made of only the polyurethane foam 11 without providing the skin material 20.

[0092] 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.

[0093] [Fifth embodiment] As shown in Figures 20(A) and 20(B), in the soundproofing material 10Y according to the fifth embodiment, a plurality of puncture marks 18 are formed in the polyurethane foam 11 by piercing the tip of a needle or blade. Specifically, the polyurethane foam 11 has a flat shape, and the puncture marks 18 extend from one of the front and back surfaces (open cell surface 11MA) 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.

[0094] In the example of the soundproofing material 10Y of this embodiment, one surface of the polyurethane foam 11 on which the puncture marks 18 are formed is exposed, and the other surface is integrated with the skin material 20, but the puncture marks 18 may be formed on the other surface side and extend through the skin material 20 to the middle of the polyurethane foam 11. The soundproofing material 10Y may be composed of only the polyurethane foam 11, or the soundproofing material 10Y may be configured such that the skin material 20 is integrated on both the front and back sides of the polyurethane foam 11. In these cases, the puncture marks 18 may be formed on only one surface side of the polyurethane foam 11, or may be formed on both sides. When the puncture marks 18 are formed on both the front and back sides of the polyurethane foam 11, it is preferable that the needle puncture marks 18 on the front and back sides of the polyurethane foam 11 are shifted so as not to overlap each other in the thickness direction of the polyurethane foam 11. This can suppress a decrease in the rigidity of the polyurethane foam 11.

[0095] The depth of the puncture mark 18 may be up to the center of the polyurethane foam 11 in the thickness direction, or up to a position close 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 mark 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. The skin layer of the polyurethane foam 11 is preferably breathable, that is, has open cells 30A 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.

[0096] 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.

[0097] The soundproofing material 10Y of this embodiment is manufactured, for example, as follows. First, a polyurethane foam 11 is obtained in a flat shape with a skin material 20 integrated on one surface in the same manner as in the first embodiment. Next, as shown in FIG. 21, a plurality of needle prick marks 18 are formed on one surface (exposed surface) of the polyurethane foam 11. Specifically, the surface of the polyurethane foam 11 opposite to the skin material 20 is placed on the upper side, and a press mold 57 (which may be, for example, a pin holder, etc.) having a plurality of needles 58 (for example, in a lattice pattern, etc.) protruding from the lower surface is pressed against the surface 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 pattern are formed. Here, since polyurethane foam 11 (especially soft polyurethane foam) has high resilience, puncture marks 18 may close when mold 57 is returned. However, even in this case, puncture marks 18 can be confirmed, for example, by magnifying a cut surface of polyurethane foam 11 with a microscope or the like.

[0098] 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.

[0099] After the piercing process is completed, a blowing process similar to that of the first embodiment is then performed on the surface of the polyurethane foam 11 on which the puncture marks 18 are formed. 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, making it easier to blow the compressed gas into the interior of the polyurethane foam 11. Note that the blowing process does not have to be performed in this embodiment.

[0100] Puncture mark 18 may penetrate skin material 20 integrated with polyurethane foam 11. In this case, skin material 20 may be integrated with the other surface of polyurethane foam 11, and needle 58 may be inserted from the other surface to form puncture mark 18 (see FIG. 22). In this case, puncture mark 18 may or may not be provided on one of the surfaces (exposed surface) of the front and back of polyurethane foam 11.

[0101] Furthermore, when the piercing process to form the needle puncture marks 18 is performed from one side of the polyurethane foam 11, the front or back, the cutting process to make the incisions 13 similar to the fourth embodiment may be performed from the other side of the polyurethane foam 11. In this case, the incisions may be linear, parallel, or lattice-shaped, and are preferably arranged so as not to overlap the puncture marks 18 when viewed from the thickness direction of the polyurethane foam 11. This makes it possible to suppress a decrease in the rigidity of the polyurethane foam 11.

[0102] In this embodiment, the needle puncture 18 is formed in the polyurethane foam 11, so that sound (air) can easily enter the polyurethane foam 11, and the sound absorption in the inner part of the polyurethane foam 11 can be improved, and the sound insulation of the soundproofing material 10Y can be improved. Furthermore, the puncture 18 is provided in the polyurethane foam 11, so that the compressed gas can be blown into the polyurethane foam 11 through the puncture 18. This makes it easier to form the break hole 32Y, and the sound absorption of the polyurethane foam 11 can be further improved. Furthermore, by forming such a puncture 18 in the polyurethane foam 11 to a position deeper than the skin layer, it is possible to easily allow air to pass through to a position deeper than the skin layer, and the sound absorption of the polyurethane foam 11 can be improved. The puncture 18 may be formed by piercing the polyurethane foam 11 halfway with the tip of a blade. The soundproofing material 10Y having such a puncture 18 can also improve the sound absorption.

[0103] [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.

[0104] (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.

[0105] (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.

[0106] (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.

[0107] (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.

[0108] (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.

[0109] (7)In the above-described fourth embodiment, a piercing process may also be performed. When performing the blow process, it is preferable to perform the piercing process before the blow process. Further, in the above-described fifth embodiment, a cutting process may also be performed. When performing the blow process, it is preferable to perform the cutting process before the blow process.

Example

[0110] Hereinafter, the above-described embodiments will be described in more detail with reference to Examples and Comparative Examples. However, the soundproof material of the present invention is not limited to the following examples.

[0111] 1. Configuration and manufacturing method of soundproof material

[0112] In Examples 1 to 4 and Comparative Examples 1 and 2, as in the manufacturing method of the above-described 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 skin material 20 was integrated only on both sides of polyurethane foam 11 to obtain a soundproof material having a size of 500 mm × 500 mm × 20 mm (thickness). Then, in Examples 1 to 4 and Comparative Example 2, post-processing described below was performed on the soundproof material of that size. In Examples 1 to 4 and Comparative Examples 1 and 2, where the thickness of polyurethane foam 11 is 16 mm and the thickness of each skin material 20 is 2 mm, the presence or absence of post-processing or the type of post-processing for polyurethane foam 11 is different from each other, and raw material 11G of polyurethane foam 11 and skin material 20 are the same.

[0113] In Examples 1 to 4 and Comparative Examples 1 and 2, as the mold release agent during foam molding, linear hydrocarbon wax "URM-520" manufactured by Konishi Co., Ltd. was used.

[0114] 1) Polyurethane foam In each example and each comparative example, raw material 11G of polyurethane foam 11 is the same. The details of the composition of raw material 11G are as follows.

[0115] <Liquid A> Polyol 1; Polyether polyol (30 parts by weight, number average molecular weight: 5500, functionality: 3.6, hydroxyl value: 31.5 mgKOH / g) Polyol 2; Polymer polyol (70 parts by weight, number average molecular weight: 5000, functionality: 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, functionality: 3, hydroxyl value 34 mgKOH / g) <Liquid B> Polyisocyanate; Polymeric MDI (NCO value 31.5%)

[0116] Note that the isocyanate index was set to 105. The isocyanate index is the 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.

[0117] 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 fiber 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 fiber with a fiber diameter of 6 denier, and the basis weight is 150 g / m 2 is. Note that 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.

[0118] 3) Type of additional processing Details of the additional processing carried out when producing the soundproofing materials of the Examples and Comparative Examples are as follows.

[0119] (1) Blow treatment In the blowing process, compressed air was blown into the soundproofing material with the tip of the nozzle N of the blow gun in contact with the surface of the soundproofing material. This blowing process was carried out on at least one of the front and back surfaces of the soundproofing material, and was carried out on the entire surface (hereinafter, the surface that was subjected to the blowing process will be referred to as the blowing process surface as appropriate). The diameter of the compressed air outlet of the nozzle N of the blow gun used was 1.6 mm, and the dynamic pressure of the compressed air blown into the soundproofing material was 0.6 MPa.

[0120] (2) Piercing 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.

[0121] (4) 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.

[0122] 4) Details of additional processing in each embodiment and comparative example Details of the additional processing in each Example and Comparative Example are as follows. Note that, hereinafter and in Fig. 24, either one of the front and back sides of the soundproofing material will be referred to as the first side, and the other side will be referred to as the second side, as appropriate.

[0123] <Example 1> Both the first and second sides (front and back) were only blow-treated. <Example 2> The first surface was only subjected to the blowing treatment, and the second surface was only subjected to the piercing treatment. <Example 3> The first surface was only subjected to blowing treatment, and no additional processing was performed on the second surface. <Example 4> The first surface was only blow-treated, and the second surface was pierced and then blow-treated. <Example 5> The first surface was only pierced, while the second surface was pierced and then blown. <Example 6> No additional processing was performed on the first surface, and the second surface was pierced and then blown. <Example 7> Both the first and second surfaces were subjected to a piercing process and then a blowing process. <Comparative Example 1> No additional processing has been performed on the soundproofing material, and therefore no breakage hole 32Y has been formed. <Comparative Example 2> Only roll crushing was performed.

[0124] 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.

[0125] <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.

[0126] (2) Airflow rate The amount of ventilation was measured based on JIS K6400-7 B method: 2012. Specifically, the soundproofing material was sliced ​​so as to divide the polyurethane foam 11 in the thickness direction to obtain three slice samples (100 mm square), and the air was passed from the bottom to the top to measure the amount of ventilation. In detail, the slice samples were a 4 mm thick portion (central slice sample) in the thickness direction of the polyurethane foam 11, the skin material 20 on the first surface side, and the skin material 20 on the second surface side. The central slice sample (polyurethane foam 11) was ventilated from the second surface side (the second surface side was placed on the lower side), and the latter two slice samples (skin material 20) were ventilated from the impregnated layer 22 side (the impregnated layer 22 side was placed on the lower side) to measure the amount of ventilation.

[0127] (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 outer peripheral surface 11E was determined as the closed cell ratio. The center region D was determined so that the center position 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 the surface region S was 2.5 mm×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.

[0128] 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.

[0129] (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.

[0130] 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.

[0131] (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.

[0132] 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.

[0133] (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.

[0134] The 50% compression hardness was evaluated as ⊚ when it was 500N or more, and as x when it was less than 500N.

[0135] (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.

[0136] 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.

[0137] (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.

[0138] 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, ×.

[0139] If all of the above evaluation items were rated as ◎, the overall rating was given as "◎", if there were ○ but no ×, the overall rating was given as "○", and if there was even one ×, the overall rating was given as "×".

[0140] <Evaluation Results> As shown in FIG. 24, it was confirmed that in Examples 1 to 7 in which a blow treatment was performed as an additional process, the reverberation chamber sound absorption coefficient was significantly improved compared to Comparative Examples 1 and 3 in which no additional process was performed (evaluation: ◎). In Examples 1 to 7, the transmission loss was also better than Comparative Examples 1 and 3 (evaluation: ○ or higher). In addition, 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 the blow treatment was performed from both sides of the soundproofing material than when it was performed only from one side. In addition, as can be seen from the comparison between Example 1 and Example 4, and the comparison between Example 1 and Example 7, it is found that the reverberation chamber sound absorption coefficient is greater when the blow treatment is performed after the piercing treatment as an additional process than when only the blow treatment is performed.

[0141] In addition, in Comparative Example 2 in which roll crushing was performed as additional processing, the reverberation chamber sound absorption coefficient and transmission loss were improved compared to Comparative Example 1 in which no additional processing was performed, but the polyurethane foam 11 was significantly deformed by roll crushing. Specifically, the polyurethane foam 11 was crushed by roll crushing, and the thickness of the polyurethane foam 11 was reduced (see thickness after additional processing). In addition, Comparative Example 2 was hardened as can be seen from a comparison of the 50% compression hardness with Comparative Example 1. 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 Example 2, the foam cells 30 are longer than in Examples 1 to 7 and Comparative Example 1. This is considered to be due to the foam cells 30 being crushed by roll crushing.

[0142] In contrast, in Examples 1 to 7 in which the blowing process 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 that of Comparative Example 1 in which no additional processing was performed (both the thickness after additional processing and the 50% compression hardness were evaluated as ⊚). Thus, it was found that the soundproofing materials of Examples 1 to 7 can improve sound absorption while preventing deterioration of dimensional accuracy due to additional processing.

[0143] As described above, it was confirmed that the soundproofing materials of Examples 1 to 7, which were subjected to blow treatment, are capable of improving sound absorption properties while preventing a decrease in dimensional accuracy, compared to the soundproofing materials of Comparative Examples 1 and 2 (overall evaluation of ○ or higher). [Explanation of symbols]

[0144] 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. 1. A soundproofing material comprising a foam, On the surface side of the foam, The foam has a structure in which the ratio of the number of open cells to the total number of foam cells is larger than that of the interior of the foam, or the foam has a structure in which the amount of air permeability is larger than that of the interior of the foam. Sound deadening materials (unless the structure is formed solely by penetrating the foam with needles or pins).

2. 1. A soundproofing material comprising a foam, The foam has a break hole formed in a cell membrane of a plurality of foam cells contained in the foam, The foam is The soundproofing material has a surface layer that has a higher apparent density than the inside of the foam and is more breathable than the inside of the foam, or has a 50% compression hardness of 500 to 3000 N based on the E method of JIS K6400-2:2012.

3. 3. The soundproofing material according to claim 1, wherein a skin material is integrated with the foam.

4. A soundproofing material comprising a foam and a skin material integrated with the foam, The number of closed cells among the foam cells of the foam is smaller near the surface of the foam than inside the foam. Or, The air permeability of the foam is greater near the surface than inside the foam. Soundproofing material.

5. 5. The soundproofing material according to claim 1, wherein the foam is sandwiched between a pair of skin materials.

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