Non-woven fabric surface material and laminated sound-absorbing material

Abstract

To provide a non-woven fabric face material capable of obtaining a laminated sound absorber indicating an excellent sound absorption characteristic.SOLUTION: In a non-woven fabric face material including 20 to 100 wt.% of thermoadhesive composite fiber, a basis weight of the non-woven fabric face material is 1 to 100 g / m2, a thickness is 0.01 to 0.15 mm and a maximum pore diameter / minimum pore diameter is 3.5 or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a non-woven fabric surface material and a laminated sound-absorbing material.

Background Art

[0002] Sound-absorbing materials made of fibers are used in automotive ceiling materials, door panels, floor mats, bonnets, trunk rooms, and building materials. In sound-absorbing materials made of fibers, it has been proposed to use a fiber structure or a non-woven fabric and improve the sound-absorbing performance by applying heat or pressure to one side thereof.

[0003] For example, in Patent Document 1, a sound-absorbing material having improved sound-absorbing performance by subjecting the surface of a non-woven fabric to heat treatment to form a film has been proposed. Further, in Patent Document 2, a method for manufacturing a fiber structure for a sound-absorbing material in which non-elastic crimped short fibers and heat-adhesive composite short fibers are arranged in the thickness direction of the fiber structure and the surface is formed into a film by heat treatment while applying pressure in the thickness direction of the fiber structure is disclosed. Although these inventions can improve their sound-absorbing performance by applying heat treatment, their performance is not sufficient and it is difficult to control the performance.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a non-woven fabric surface material capable of obtaining a laminated sound-absorbing material exhibiting good sound-absorbing characteristics.

Means for Solving the Problems

[0006] That is, the present invention is a non-woven fabric surface material containing 20 to 100% by weight of heat-adhesive composite fibers, wherein the basis weight of the non-woven fabric surface material is 1 to 100 g / m 2 , the thickness is 0.01 to 0.15 mm, and the maximum pore diameter / minimum pore diameter is 3.5 or more, and it is a non-woven fabric surface material.

[0007] The present invention is also a method for manufacturing a non-woven fabric surface material, which uses heat-adhesive composite fibers with a fiber diameter of 7 to 20 μm containing a heat-adhesive component to form a web containing 20 to 100% by weight of heat-adhesive composite fibers, and presses the web at a temperature higher than the melting point of the heat-adhesive component of the heat-adhesive composite fibers, and the web is made to have a thickness of 0.01 to 0.15 mm and a maximum pore diameter / minimum pore diameter of 3.5 or more, and it is a method for manufacturing a non-woven fabric surface material including a heat-pressing step.

Effects of the Invention

[0008] According to the present invention, it is possible to provide a non-woven fabric surface material capable of obtaining a laminated sound-absorbing material exhibiting good sound-absorbing characteristics.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail.

[0011] 〔Non-woven fabric surface material〕 The non-woven fabric surface material of the present invention is a non-woven fabric surface material containing heat-adhesive composite fibers. The heat-adhesive composite fibers contain a fiber-forming component and a heat-adhesive component. This heat-adhesive composite fiber preferably has a core-sheath structure. In this core-sheath structure, the sheath component consists of a heat-adhesive component, and the core component consists of a fiber-forming component.

[0012] Examples of the fiber-forming component include polyesters such as polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate, and polyolefins, with polyethylene terephthalate being preferred. When it is polyethylene terephthalate, its intrinsic viscosity is, for example, 0.30 to 0.80 dl / g, preferably 0.40 to 0.70 dl / g. If it is less than 0.30 dl / g, the fiber becomes too fragile, leading to breakage and deterioration during the process of forming into a nonwoven fabric, which is unsuitable. If it is greater than 0.80 dl / g, it becomes difficult to be crushed during the pressing process described later, which is also unsuitable.

[0013] As the heat-adhesive component, a polymer having a melting point in the range of 100 to 200 °C or a glass transition temperature in the range of 50 to 110 °C is used. Examples of this polymer include copolymerized polyester polymers, polyester-based elastomers, polyurethane-based elastomers, non-elastic polyester-based polymers and their copolymers, polyolefin-based polymers and their copolymers, and polyvinyl alcohol-based polymers.

[0014] Examples of the copolymerized polyester polymer include copolyesters containing a predetermined number of aliphatic dicarboxylic acids such as adipic acid and sebacic acid, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and / or alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, and aliphatic and alicyclic diols such as diethylene glycol, polyethylene glycol, propylene glycol, and paraxylene glycol, and optionally adding oxyacids such as parahydroxybenzoic acid as desired. For example, a polyester obtained by adding and copolymerizing isophthalic acid and 1,6-hexanediol to terephthalic acid and ethylene glycol can be used.

[0015] As the polyurethane-based elastomer, it is a polymer obtained by the reaction of a low melting point polyol having a molecular weight of about 500 to 6000, such as dihydroxy polyether, dihydroxy polyester, dihydroxy polycarbonate, dihydroxy polyester amide, etc., an organic diisocyanate having a molecular weight of 500 or less, such as p,p'-diphenylmethane diisocyanate, tolylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane isocyanate, xylylene isocyanate, 2,6-diisocyanate methyl caproate, hexamethylene diisocyanate, etc., and a chain extender having a molecular weight of 500 or less, such as glycol amino alcohol or triol.

[0016] Among these polymers, particularly preferred is polyurethane using polytetramethylene glycol, or poly-ε-caprolactam or polybutylene adipate as the polyol. Examples of the organic diisocyanate in this case include p,p'-bishydroxyethoxybenzene and 1,4-butanediol.

[0017] In addition, examples of the polyester-based elastomer include a polyether ester copolymer obtained by copolymerizing a thermoplastic polyester as a hard segment and a poly(alkylene oxide) glycol as a soft segment. More specifically, alicyclic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; aliphatic dicarboxylic acids such as succinic acid, oxalic acid, adipic acid, sebacic acid, dodecanedioic acid, and dimer acid, or at least one of these dicarboxylic acids or their ester-forming derivatives; at least one of diol components selected from aliphatic diols such as 1,4-butanediol, ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, and decamethylene glycol, alicyclic diols such as 1,1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, and tricyclodecanemethanol, or their ester-forming derivatives; and a terpolymer composed of at least one of poly(alkylene oxide) glycols such as polyethylene glycol with an average molecular weight of about 400 to 5000, poly(1,2- and 1,3-propylene oxide) glycol, poly(tetramethylene oxide) glycol, a copolymer of ethylene oxide and propylene oxide, and a copolymer of ethylene oxide and tetrahydrofuran can be mentioned.

[0018] In particular, from the viewpoints of adhesiveness, temperature characteristics, and strength, a block copolymer polyether ester having polybutylene terephthalate as a hard component and polyoxybutylene glycol as a soft segment is preferable. In this case, the polyester portion constituting the hard segment is polybutylene terephthalate in which the main acid component is terephthalic acid and the main diol component is a butylene glycol component. Of course, a part of this acid component (usually 30 mol% or less) may be substituted with other dicarboxylic acid components or oxycarboxylic acid components, and similarly, a part of the glycol component (usually 30 mol% or less) may be substituted with a dioxy component other than the butylene glycol component. Further, the polyether portion constituting the soft segment may be a polyether substituted with a dioxy component other than butylene glycol.

[0019] Examples of the polyolefin-based polymer used as the thermoadhesive component include polypropylene, high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, a crystalline propylene copolymer composed of propylene and other α-olefins, and those obtained by copolymerizing these with styrene, acrylic acid, methacrylic acid, maleic acid, etc.

[0020] The thermoadhesive composite fiber is a composite fiber in which at least the thermoadhesive component is exposed on the surface of the composite fiber. The thermoadhesive component is used as a sheath component and the fiber-forming component is used as a core component, and both components are compounded in a core-sheath type or an eccentric sheath-core type; the thermoadhesive component and the fiber-forming component are compounded in a parallel type (side-by-side type); the fiber-forming component is in the form of islands and the thermoadhesive component is in the form of a sea, i.e., a sea-island type composite fiber; a segment pie type composite fiber in which the thermoadhesive component and the fiber-forming component are alternately arranged. Among them, it is particularly preferable to compound in a core-sheath type.

[0021] The proportion of the thermoadhesive component in the thermoadhesive composite fiber is preferably 40 to 95% by weight, more preferably 45 to 90% by weight, and particularly preferably 50 to 80% by weight based on the weight of the thermoadhesive composite fiber. If it is less than 40% by weight, the amount of the polymer forming the film by heat melting is small, so that the target sound absorption performance cannot be obtained, which is not preferable. On the other hand, if it exceeds 95% by weight, it becomes difficult to stably melt-spin the composite fiber, which is not preferable.

[0022] The fiber diameter of the thermoadhesive composite fiber used for manufacturing the nonwoven fabric surface material of the present invention is preferably 7 to 20 μm, more preferably 10 to 17 μm. This fiber diameter is the fiber diameter of the fiber before being subjected to the heat pressing process for manufacturing the nonwoven fabric surface material of the present invention. If the fiber diameter is less than 7 μm, the nonwoven fabric becomes dense and is likely to reflect sound waves in the high frequency range, which is not preferable. On the other hand, if it exceeds 20 μm, it is difficult to obtain a nonwoven fabric with the maximum pore diameter / minimum pore diameter described below, and the sound absorption performance becomes poor, which is not preferable.

[0023] The proportion of the thermoadhesive composite fiber contained in the nonwoven fabric surface material is 20 to 100% by weight, preferably 30 to 100% by weight, and more preferably 50 to 100% by weight. If it is less than 20% by weight, the surface film portion formed by the melting and flowing of the thermoadhesive component due to heating and pressure becomes insufficient, the size of the apertures also becomes small, and sufficient sound absorption performance cannot be obtained.

[0024] The nonwoven fabric surface material may contain fibers other than the thermoadhesive composite fiber as long as the physical properties described below are satisfied. As the fiber, synthetic fibers are preferable, and examples thereof include polyester fibers, nylon fibers, acrylic fibers, polyolefin fibers, etc., and polyester fibers are preferable. The fiber diameter is, for example, 5 to 25 μm, preferably 7 to 20 μm.

[0025] The nonwoven fabric surface material may contain ultrafine fibers having a fiber diameter of 10 μm or less for a single fiber. By including such ultrafine fibers, when combined with the nonwoven fabric surface material, the nonwoven fabric as the base material can attenuate sound waves, and further improve the sound absorption performance.

[0026] 〔Areal density, thickness, and porosity of the nonwoven fabric surface material〕 The areal density of the nonwoven fabric surface material is 1 to 100 g / m 2 , preferably 10 to 100 g / m 2 , more preferably 20 to 60 g / m 2 . If the areal density is less than 1 g / m 2 , there is a risk that sufficient sound absorption performance cannot be obtained. On the other hand, if the areal density exceeds 100 g / m 2 , sound waves in the high-frequency region are reflected, and the sound absorption performance in the same region tends to decrease.

[0027] The thickness of the nonwoven fabric surface material of the present invention is 0.01 to 0.15 mm, preferably 0.03 to 0.12 mm, and more preferably 0.05 to 0.10 mm. If the thickness is less than 0.01 mm, sound waves in the high-frequency region are reflected, and the target sound absorption performance cannot be obtained. If the thickness exceeds 0.15 mm, the target sound absorption performance cannot be obtained.

[0028] The porosity of the nonwoven fabric surface material is preferably 30 to 70%, and more preferably 40 to 65%. If it is less than 30%, the sound absorption rate of sound waves in the high-frequency region tends to decrease, which is not preferable. On the other hand, if it exceeds 70%, it becomes difficult to obtain the target sound absorption performance.

[0029] 〔Maximum pore diameter / minimum pore diameter of the nonwoven fabric surface material〕 The nonwoven fabric surface material of the present invention needs to have a maximum pore diameter / minimum pore diameter of 3.5 or more, preferably 4 or more, and more preferably 5 or more. This maximum pore diameter / minimum pore diameter is the ratio (maximum pore diameter / minimum pore diameter) of the maximum pore diameter (μm) to the minimum pore diameter (μm) in the pore diameter distribution measured by a palm porosimeter.

[0030] When the maximum pore diameter / minimum pore diameter is 3.5 or more, due to the above-described estimation mechanism, the energy loss due to vortices and turbulence accompanying the expansion and contraction of the flow path increases, and high sound absorption performance can be obtained.

[0031] The ratio of the maximum pore diameter to the minimum pore diameter is preferably 20 or less, more preferably 15 or less. By being 20 or less, it is preferable because it is possible to obtain sound absorption performance with a preferable balance between the low-frequency range and the high-frequency range.

[0032] Note that the maximum pore diameter and the minimum pore diameter measured by the palm porometer are, as described above, the ratio (maximum pore diameter / minimum pore diameter) of the maximum pore diameter (μm) and the minimum pore diameter (μm) in the pore diameter distribution measured by the palm porometer, and do not mean the maximum pore diameter and the minimum pore diameter in the same flow path. However, in the study of the inventors, the ratio (maximum pore diameter / minimum pore diameter) of the maximum pore diameter (μm) and the minimum pore diameter (μm) in the pore diameter distribution measured by the palm porometer is effective as an index of the sound absorption performance of the nonwoven fabric surface material.

[0033] By increasing the temperature and pressure during the thermocompression treatment and by lengthening the heating and pressing time, the ratio of the maximum pore diameter to the minimum pore diameter can be increased. Further, by increasing the proportion of the thermally adhesive composite fibers contained in the nonwoven fabric surface material, a film is sufficiently formed on the surface of the nonwoven fabric surface material. As a result, the minimum pore diameter becomes smaller and the ratio of the maximum pore diameter to the minimum pore diameter can be increased.

[0034] 〔Method for manufacturing nonwoven fabric surface material〕 The nonwoven fabric surface material of the present invention that satisfies the above conditions is formed by using thermally adhesive composite fibers having a fiber diameter of 7 to 20 μm containing a thermally adhesive component to form a web containing 20 to 100% by weight of the thermally adhesive composite fibers, and pressing the web at a temperature higher than the melting point of the thermally adhesive component of the thermally adhesive composite fibers, and can be manufactured by a heating and pressing step of making the web have a thickness of 0.01 to 0.15 mm and a ratio of the maximum pore diameter to the minimum pore diameter of 3.5 or more.

[0035] That is, according to the present invention, there is provided a method for manufacturing a nonwoven fabric surface material, comprising: a web forming step of forming a web containing 20 to 100% by weight of thermally adhesive composite fibers having an average fiber diameter of 7 to 20 μm and containing a thermally adhesive component; and a heating and pressing step of pressing the web at a temperature higher than the melting point of the thermally adhesive component of the thermally adhesive composite fibers to make the web have a thickness of 0.01 to 0.15 mm and a maximum pore diameter / minimum pore diameter of 3.5 or more.

[0036] In the web forming step, as a method for forming the web, a conventionally known method can be used, preferably the card method, the airlaid method, or the wet papermaking method. In the web formed in the web forming step, the content of the thermally adhesive composite fibers is 20 to 100% by weight, preferably 30 to 100% by weight, more preferably 50 to 100% by weight.

[0037] 〔Heating and Pressing Step〕 In the heating and pressing step, the nonwoven fabric surface material of the present invention is obtained by subjecting the web obtained in the web making step to hot pressing. Examples of the hot pressing method include a method of pressing with a heated flat plate and a calendar method of gripping with a pair of rollers heated on both sides.

[0038] The hot pressing conditions are appropriately adjusted for the processing temperature, pressure, and time so that the thickness and the maximum pore diameter / minimum pore diameter of the obtained nonwoven fabric surface material fall within a predetermined range, particularly 3.5 or more. After manufacturing the web, the obtained web may be directly subjected to the heating and pressing step, or may be subjected to heat treatment by an air-through dryer or the like and then subjected to the heating and pressing step.

[0039] In the heating and pressing step, it is important to heat and press the web from both sides. By doing so, fine openings are formed on both sides of the nonwoven fabric surface material obtained from the web, and the sound wave attenuation effect due to the expansion and contraction of the flow paths described later can be sufficiently obtained.

[0040] Since the non-woven fabric surface material of the present invention contains thermally adhesive composite fibers, adhesion to the surface of the hot plate of the press or the calendar roller may occur in the heat pressing process. Therefore, it is desirable to combine measures such as applying a special coating or micro-roughening process to suppress adhesion on the surface of the roller or flat plate, or using a release agent. When using a calendar roller, the non-woven fabric surface material after heat pressing can be taken up with an appropriate tension, and adhesion to the roller can be suppressed.

[0041] In the non-woven fabric surface material, it is preferable that 80% or more of the area of the non-woven fabric surface material is heat pressed in the heat pressing process. That is, in the heat pressing process, it is preferable that not partial crimping such as embossing but 80% or more of the area of the non-woven fabric surface material is subjected to heat and pressure by a flat plate or a roller. By doing so, the area of the crimped portion contributing to sound absorption can be increased, and high sound absorption performance can be obtained.

[0042] In the non-woven fabric surface material of the present invention, since the pressure is applied in a state where the thermally adhesive component in the thermally adhesive composite fiber is sufficiently melted by heat, the fibers of the non-woven fabric surface material adhere to each other, and a water-draining film derived from the thermally adhesive component is formed on the front and back surfaces of the non-woven fabric surface material. This state can be observed, for example, by a scanning electron microscope (Figure 1).

[0043] Conventionally, in fiber-made porous materials such as non-woven fabrics, it has been said that sound absorption performance is exhibited by attenuation of sound waves in the boundary layer where air movement is difficult to occur, which is formed on the fiber surface. Therefore, in the conventional technology, it is common to configure the non-woven fabric surface material with ultra-fine fibers having an average fiber diameter of less than 7 μm with a large specific surface area so that the total fiber surface area serving as a sound absorption field becomes large per unit weight.

[0044] In contrast, the nonwoven fabric surface material of the present invention is composed of fibers with a larger fiber diameter to form a nonwoven fabric, and fine pores are formed on its front and back surfaces by a film of a thermally adhesive component, and relatively large voids are formed inside. Due to the combination of these fine pores and voids, a rapid expansion and contraction of the sound wave flow path occur, and along with this, vortices and turbulence are induced, and the energy of the sound wave is attenuated.

[0045] The mechanism by which the nonwoven fabric surface material of the present invention exhibits sound absorption performance has not been fully clarified, but the inventor has made the above-mentioned presumption.

[0046] 〔Laminated sound-absorbing material〕 The present invention also relates to a laminated sound-absorbing material including the above-mentioned nonwoven fabric surface material of the present invention and a porous base material. In this laminated sound-absorbing material, the nonwoven fabric surface material of the present invention may be directly laminated with the porous base material, or may be laminated with an air layer disposed therebetween. When disposing an air layer, it is preferable to maintain the air layer between the nonwoven fabric surface material and the porous base material by appropriately using a spacer. The nonwoven fabric surface material may be laminated on one side of the porous base material, or may be laminated on both sides.

[0047] As a method of laminating the nonwoven fabric surface material and the porous base material to integrate the two, known methods conventionally used can be used. For example, a method using a powdery binder or a spider web-like low melting point fiber sheet (Spunfab (registered trademark)) can be used.

[0048] 〔Porous base material〕 Hereinafter, the porous base material used when laminating the nonwoven fabric surface material of the present invention to the porous base material will be described. As the porous base material, a porous base material having air permeability is used. Examples of this porous base material include nonwoven fabric, woven fabric, and continuous bubble foam, and nonwoven fabric is preferable. These may be used in combination.

[0049] The nonwoven fabric used as the porous substrate can be manufactured by a conventionally known method. For example, it can be obtained by mixing fibers and thermally adhesive fibers, spinning a uniform web using a roller card, laminating the fibers in the horizontal direction, and then performing a heat treatment.

[0050] Specifically, for example, a method can be used in which, using a heat treatment machine as shown in FIG. 1 of JP-A-2008-68799, the web is heat-treated while being folded in an accordion shape to form fixed points by thermal fusion. In this case, for example, an apparatus shown in JP-T-2002-516932 (a commercially available product, for example, Struto equipment manufactured by Struto Co., Ltd.) may be used.

[0051] The basis weight of the porous substrate is preferably 50 to 2000 g / m 2 and more preferably 100 to 1500 g / m 2 If it is less than 50 g / m 2 there is a risk that sufficient sound absorption performance cannot be obtained, which is not preferable. If it is greater than 2000 g / m 2 the weight of the sound absorption material increases, which is not preferable.

[0052] The thickness of the porous substrate is preferably 5 mm or more, preferably 5 to 50 mm, and particularly preferably 8 to 20 mm. If the thickness is less than 5 mm, there is a risk that sufficient sound absorption cannot be obtained, which is not preferable.

[0053] 〔Orientation of the laminated sound absorption material〕 The laminated sound absorption material of the present invention is used with the surface on which the nonwoven fabric facing material is laminated arranged on the sound source side. By arranging the nonwoven fabric facing material on the sound source side, the sound source is arranged at a position where the vibration velocity of the particles is large, that is, at a position where the sound energy is large, and the incident sound can be attenuated more efficiently.

[0054] When the non-woven fabric surface material is laminated on both sides of the porous base material, the non-woven fabric surface material is laminated on both the sound source side and the non-sound source side so as to sandwich the porous base material. In this case, since there is no distinction between the front and back of the laminated sound-absorbing material, the handleability is improved, and furthermore, better sound-absorbing properties can be obtained. In addition, known functional processing such as dyeing processing, water-repellent processing, flame-retardant processing, and flame-resistant processing may be added to the laminated sound-absorbing material without any problem.

Examples

[0055] Examples and comparative examples of the present invention will be described in detail. Each measurement item in the examples was measured by the following method.

[0056] (1) Melt viscosity The polymer after the drying treatment was set in an orifice set at the melt temperature of the extruder at the time of spinning and held molten for 5 minutes, and then extruded under several levels of load, and the shear rate and melt viscosity at that time were plotted. The plot was smoothly connected to create a shear rate - melt viscosity curve, and the melt viscosity at a shear rate of 1000 seconds -1 was observed.

[0057] (2) Melt flow rate (MFR) It was measured in accordance with JIS K7210 at a temperature of 190 °C and a load of 2.169 kg.

[0058] (3) Melting point A TA-2200 differential scanning calorimeter DSC manufactured by TA Instruments was used. The measurement was performed on 10 mg of the sample at a heating rate of 20 °C / min in a nitrogen atmosphere.

[0059] (4) Fiber diameter and fiber length The fiber diameter was measured using an image taken at a magnification of 1000 times with a scanning electron microscope (JCM-5700, JEOL Ltd.) of the cross-section of the web test piece before thermocompression processing. In the electron microscope cross-sectional photograph of each sample, 10 fibers that were cut approximately perpendicular to the fiber axis direction were arbitrarily selected, their fiber diameters were measured, and the average value (μm) was calculated as the fiber diameter. Whether it is a composite fiber or other fibers was determined from the cross-sectional shape, and the fiber diameters were calculated separately after distinction. The fiber length was measured by the method described in JIS L 1015:2010 8.4.1 Method A. In this measurement of the fiber length, unlike the measurement of the fiber diameter described above, the fiber length of the fibers used as the raw material of the nonwoven fabric surface material was measured.

[0060] (5) Areal density, total areal density In accordance with JIS L 1096, the areal density (g / m 2 ) and the total areal density (g / m 2 ) were measured.

[0061] (6) Thickness The thickness (mm) of the nonwoven fabric surface material was measured in accordance with JIS P 8118. The thickness (mm) of the composite sound-absorbing material was measured in accordance with JIS L 1096. In both cases, the average value was calculated with n = 5.

[0062] (7) Porosity From the areal density, thickness, and resin density, the value was obtained using the following calculation formula, and the porosity was obtained by rounding off the first decimal place of the obtained value. Porosity (%) = 100 - {areal density (g / m 2 ) × 100 / resin density (g / cm 3 ) / thickness (mm) / 1000}

[0063] (8) Maximum pore diameter / minimum pore diameter As a measuring device, a palm porometer (model: CFP-1200-AEXL) manufactured by PMI was used. For the immersion liquid, GALWICK immersion liquid (surface tension: 15.9 dynes / cm) manufactured by PMI was used, and a wetting flow curve was obtained based on the bubble point method specified in ASTM F316-86. At this time, the maximum pore diameter was obtained by substituting the bubble point pressure into the bubble point formula. Next, a dry flow curve was obtained for the same sample, and the minimum pore diameter was obtained by substituting the pressure when the flow rate in the dry flow curve matched the flow rate in the previously obtained wetting flow curve into the bubble point formula. The value of the maximum pore diameter / minimum pore diameter was calculated from the obtained values of the maximum pore diameter and the minimum pore diameter, and rounded to the second decimal place. The measurement was performed with n = 5, the values were calculated, and the average value was calculated.

[0064] (9) Sound absorption characteristics Based on JIS A1405, the normal incidence sound absorption rate of building materials by the in-duct method was measured at 1 / 3 octave center frequencies of 1000 Hz and 2000 Hz, and the average value was calculated with n = 5. Furthermore, the average sound absorption rate obtained by arithmetically averaging the sound absorption rates at 1000 Hz and 2000 Hz was determined and used as an index of sound absorption performance. Next, the manufacturing methods of the non-woven fabric surface material and the porous base material used in the examples and comparative examples will be described. These were manufactured by the following methods.

[0065] (10) Fiber fineness It was measured by the method described in Japanese Industrial Standard JIS L 1015:2010 8.5.1 Method A.

[0066] (Production of non-woven fabric surface material A) Polyethylene terephthalate with a single fiber fineness of 1.7 dtex (fiber diameter 12.5 μm) and a fiber length of 5 mm (melting point 256 °C) is arranged in the core part, and a copolymerized polyethylene terephthalate (melting point 155 °C) consisting of an acid component in which terephthalic acid and isophthalic acid are mixed at 80 / 20 (mol%) and a diol component in which ethylene glycol and tetraethylene glycol are mixed at 35 / 65 (mol%) is arranged in the sheath part. Using 100% by weight of the core-sheath type thermally adhesive composite short fibers obtained by spinning by a conventional method so that the weight ratio of sheath / core is 50 / 50, a web was obtained with a known airlaid nonwoven fabric manufacturing apparatus. Next, the web was heat-treated at 180 °C for 1 minute using a hot air circulation dryer to obtain a nonwoven fabric.

[0067] A 15 cm × 15 cm square was cut from the obtained nonwoven fabric, held with a polyimide film, and then, using a flat press machine, the entire surface of the nonwoven fabric was evenly pressed at a hot plate temperature of 150 °C and a press pressure of 10 kg / cm 2 for 10 seconds, and then cooled to obtain a nonwoven fabric surface material A (basis weight 40 g / m 2 ). The basis weight, thickness, and maximum pore diameter / minimum pore diameter of the obtained nonwoven fabric surface material were measured.

[0068] (Production of nonwoven fabric surface material B) Polyethylene terephthalate with a single fiber fineness of 1.7 dtex (fiber diameter 13.6 μm) and a fiber length of 5 mm (melting point 256 °C) is arranged in the core part, and high-density polyethylene (melting point 130 °C, melt flow rate 20 g / min) is arranged in the sheath part. Using 100% by weight of the core-sheath type thermally adhesive composite short fibers obtained by spinning by a conventional method so that the weight ratio of sheath / core is 50 / 50, a web was obtained with a known airlaid nonwoven fabric manufacturing apparatus. Next, the web was heat-treated at 180 °C for 1 minute using a hot air circulation dryer to obtain a nonwoven fabric.

[0069] A 15 cm × 15 cm square was cut from the obtained nonwoven fabric, held with a polyimide film, and then, using a hot press machine, the entire surface of the nonwoven fabric was evenly pressed at a hot plate temperature of 130 °C and a pressure of 10 kg / cm 2 for 10 seconds, and then cooled to obtain a nonwoven fabric surface material B (basis weight 40 g / m 2) was obtained. The basis weight, thickness, and maximum pore diameter / minimum pore diameter of the obtained nonwoven fabric surface material were measured.

[0070] (Production of nonwoven fabric surface material C) Polyethylene terephthalate (melting point 256°C) with a single fiber fineness of 2.2 dtex (fiber diameter 14.4 μm) and a fiber length of 51 mm was placed in the core part, and a copolymerized polyethylene terephthalate (softening point 110°C) composed of an acid component in which terephthalic acid and isophthalic acid were mixed at 60 / 40 (mol%) and ethylene glycol as the diol component was placed in the sheath part. 70% by weight of the core-sheath type thermally adhesive composite short fibers obtained by spinning by a conventional method so that the sheath / core weight ratio was 50 / 50, and 30% by weight of polyethylene terephthalate (PET) crimped short fibers with a single fiber fineness of 0.6 dtex (fiber diameter 7.4 μm) and a fiber length of 32 mm were mixed, and a web was obtained with a known card nonwoven fabric manufacturing apparatus. Next, the web was heat-treated at 180°C for 1 minute using a hot air circulation dryer to obtain a nonwoven fabric.

[0071] A 15 cm × 15 cm square was cut from the obtained nonwoven fabric, gripped with a polyimide film, and then, with a hot press machine, the entire surface of the nonwoven fabric was evenly pressed at a hot plate temperature of 150°C and a pressure of 10 kg / cm 2 for 10 seconds, and then cooled to obtain nonwoven fabric surface material C (basis weight 40 g / m 2 ). The basis weight, thickness, and maximum pore diameter / minimum pore diameter of the obtained nonwoven fabric surface material were measured.

[0072] (Production of nonwoven fabric surface material D) In nonwoven fabric surface material C, 50% by weight of the core-sheath type thermally adhesive composite short fibers and 50% by weight of single fiber fineness 0.6 dtex were mixed, and the rest was the same as the production of nonwoven fabric surface material C to obtain nonwoven fabric surface material D (basis weight 40 g / m 2 ). The basis weight, thickness, and maximum pore diameter / minimum pore diameter of the obtained nonwoven fabric surface material were measured.

[0073] (Production of nonwoven fabric surface material E) In nonwoven fabric surface material D, the nonwoven fabric before pressing with a hot press machine was used as nonwoven fabric surface material E (basis weight 40 g / m 2) was used. The basis weight and thickness of the obtained nonwoven fabric surface material were measured. The maximum pore diameter / minimum pore diameter could not be obtained because the flow rate in the dry flow curve did not match the flow rate in the wet flow curve and the minimum pore diameter could not be measured.

[0074] (Production of nonwoven fabric surface material F) In the nonwoven fabric surface material D, the pressure of the hot press machine was 1 kg / cm 2 and the product made as such was designated as nonwoven fabric surface material F (basis weight 40 g / m 2 ). The basis weight, thickness, and maximum pore diameter / minimum pore diameter of the obtained nonwoven fabric surface material were measured.

[0075] (Production of nonwoven fabric surface material G) In the nonwoven fabric surface material F, 30% by weight of core-sheath type thermally adhesive composite short fibers and 70% by weight of single fiber fineness 0.6 dtex were mixed, and the rest was made in the same manner as the production of the nonwoven fabric surface material F to obtain nonwoven fabric surface material G (basis weight 40 g / m 2 ). The basis weight, thickness, and maximum pore diameter / minimum pore diameter of the obtained nonwoven fabric surface material G were measured.

[0076] (Production of porous base material a) Crimped short fiber A (fineness 2.2 dtex, single fiber diameter 14 μm, fiber length 51 mm) made of polyethylene terephthalate (PET), and core-sheath composite type thermally adhesive short fiber (fiber fineness 2.2 dtex, single fiber diameter 14 μm, fiber length 51 mm, core / sheath = 50 / 50 (weight%), core: polyethylene terephthalate with a melting point of 256 °C, sheath: copolymer polyester with a softening point of 110 °C mainly composed of terephthalic acid, isophthalic acid, ethylene glycol, and diethylene glycol) as the thermally adhesive composite short fiber (binder fiber) were used. The crimped short fiber and the thermally adhesive composite short fiber were blended at a mixing ratio of 80 / 20 (weight%) and passed through a carding machine to form a nonwoven web with a basis weight of 110 g / m 2 .

[0077] The obtained nonwoven web was sandwiched between wire meshes together with a spacer with a thickness of 16 mm and heat-treated in a hot air dryer at 140 °C for 15 minutes to obtain a porous base material a with a thickness of 16 mm and a basis weight of 110 g / m 2 .

[0078] (Production of Porous Substrate b) A porous substrate b with a thickness of 16 mm and a basis weight of 150 g / m was obtained in the same composition and method as the porous substrate a 2 .

[0079] (Production of Porous Substrate c) Crimped staple fiber A (fiber fineness 2.2 dtex, single fiber diameter 14 μm, fiber length 51 mm) made of polyethylene terephthalate (PET), crimped staple fiber B (fiber fineness 0.11 dtex, single fiber diameter 3.2 μm, fiber length 32 mm), and core-sheath composite type thermally adhesive short fiber (binder fiber) as the thermally adhesive composite short fiber (fiber fineness 2.2 dtex, single fiber diameter 14 μm, fiber length 51 mm, core / sheath = 50 / 50 (wt%), core: polyethylene terephthalate with a melting point of 256 °C, sheath: copolymer polyester with a softening point of 110 °C mainly composed of terephthalic acid, isophthalic acid, ethylene glycol, and diethylene glycol) were used. The crimped staple fiber A, crimped staple fiber B, and thermally adhesive composite short fiber were blended at a mixing ratio of 40 / 40 / 20 (wt%) and carded to form a nonwoven web with a basis weight of 110 g / m 2 .

[0080] The obtained nonwoven web was sandwiched between wire meshes together with a spacer with a thickness of 16 mm and heat-treated in a hot air dryer at 140 °C for 15 minutes to obtain a porous substrate c with a thickness of 16 mm and a basis weight of 110 g / m 2 .

[0081] (Production of Porous Substrate d) A porous substrate d with a thickness of 16 mm and a basis weight of 150 g / m was obtained in the same composition and method as the porous substrate c 2 .

[0082] [Example 1] Using nonwoven fabric facing material A as the nonwoven fabric facing material and porous substrate a as the porous substrate, the two were laminated and adhered between layers to obtain a total basis weight of 150 g / m 2A laminated sound-absorbing material was obtained. The adhesion was carried out by spraying an adhesive on the adhesion surfaces of both and bringing the adhesion surfaces of both into contact. The normal incidence sound absorption rate of the obtained laminated sound-absorbing material was measured, and the sound absorption rates at frequencies of 1000 Hz and 2000 Hz and their arithmetic mean values were determined.

[0083] 〔Examples 2 to 5〕 As shown in Table 1, a laminated sound-absorbing material with a total basis weight of 150 g / m was obtained in the same manner as in Example 1 except that the combination of the non-woven fabric facing material and the porous base material was changed. 2 The normal incidence sound absorption rate of the obtained laminated sound-absorbing material was measured, and the sound absorption rates at frequencies of 1000 Hz and 2000 Hz and their arithmetic mean values were determined.

[0084] 〔Comparative Examples 1 to 3〕 As shown in Table 2, a laminated sound-absorbing material with a total basis weight of 150 g / m was obtained in the same manner as in Example 1 except that the combination of the non-woven fabric facing material and the porous base material was changed. 2 The normal incidence sound absorption rate of the obtained laminated sound-absorbing material was measured, and the sound absorption rates at frequencies of 1000 Hz and 2000 Hz and their arithmetic mean values were determined. In Comparative Example 1, the minimum pore diameter could not be measured.

[0085] 〔Comparative Example 4〕 The normal incidence sound absorption rate of the sound-absorbing material made of a single-layer non-woven fabric of the porous base material b was measured, and the sound absorption rates at frequencies of 1000 Hz and 2000 Hz and their arithmetic mean value were determined.

[0086] 〔Comparative Example 5〕 The normal incidence sound absorption rate of the sound-absorbing material made of a single-layer non-woven fabric of the porous base material d was measured, and the sound absorption rates at frequencies of 1000 Hz and 2000 Hz and their arithmetic mean value were determined.

[0087]

Table 1

[0088]

Table 2

Industrial Applicability

[0089] It can be suitably used as a sound-absorbing material for automobiles, electronic devices, buildings, housing, etc.

Claims

1. A non-woven fabric facing material containing 20 to 100% by weight of heat-bondable composite fibers, wherein the basis weight of the non-woven fabric facing material is 1 to 100 g / m ２ , the thickness is 0.01 to 0.15 mm and the maximum pore diameter / minimum pore diameter is 3.5 or more, and the heat-bondable composite fiber has a core-sheath structure, and the sheath component is a heat-bondable component. A non-woven fabric facing material.

2. A non-woven fabric facing material containing 20 to 100% by weight of heat-bondable composite fibers, wherein the basis weight of the non-woven fabric facing material is 1 to 100 g / m ２ , the thickness is 0.03 to 0.12 mm and the maximum pore diameter / minimum pore diameter is 3.5 or more. A non-woven fabric facing material.

3. A non-woven fabric facing material containing 20 to 100% by weight of heat-bondable composite fibers, wherein the basis weight of the non-woven fabric facing material is 1 to 100 g / m ２ , the thickness is 0.01 to 0.15 mm and the maximum pore diameter / minimum pore diameter is 3.5 or more, and the porosity is 30 to 70%. A non-woven fabric facing material.

4. The non-woven fabric facing material according to claim 1 or 2, wherein the heat-bondable composite fiber has a core-sheath structure and the sheath component is a heat-bondable component.

5. A laminated sound-absorbing material comprising the non-woven fabric facing material according to any one of claims 1 to 4 and a porous base material.

6. A non-woven fabric facing material containing 20 to 100% by weight of heat-bondable composite fibers, wherein the basis weight of the non-woven fabric facing material is 1 to 100 g / m ２ , the thickness is 0.01 to 0.15 mm and the maximum pore diameter / minimum pore diameter is 3.5 or more. A laminated sound-absorbing material comprising the non-woven fabric facing material and a porous base material.

7. The laminated sound-absorbing material according to claim 5 or 6, wherein the porous base material is a non-woven fabric.

8. A method for manufacturing a non-woven fabric surface material, comprising a web forming step of forming a web containing 20 to 100% by weight of thermally adhesive composite fibers having a fiber diameter of 7 to 20 μm and containing a thermally adhesive component, and pressing the web at a temperature higher than the melting point of the thermally adhesive component of the thermally adhesive composite fibers, and a heat pressing step of making the web have a thickness of 0.01 to 0.15 mm and a maximum pore diameter / minimum pore diameter of 3.5 or more.

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