WO2023190398A1 - Matériau absorbant acoustique - Google Patents

Matériau absorbant acoustique Download PDF

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Publication number
WO2023190398A1
WO2023190398A1 PCT/JP2023/012311 JP2023012311W WO2023190398A1 WO 2023190398 A1 WO2023190398 A1 WO 2023190398A1 JP 2023012311 W JP2023012311 W JP 2023012311W WO 2023190398 A1 WO2023190398 A1 WO 2023190398A1
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WIPO (PCT)
Prior art keywords
layer
nonwoven fabric
absorbing material
sound absorbing
sound
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PCT/JP2023/012311
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English (en)
Japanese (ja)
Inventor
太郎 市川
千秋 花巻
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三井化学株式会社
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Publication of WO2023190398A1 publication Critical patent/WO2023190398A1/fr

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Classifications

    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/162—Selection of materials
    • G10K11/168—Plural layers of different materials, e.g. sandwiches

Definitions

  • the present disclosure relates to sound absorbing materials.
  • Sound-absorbing materials are products that have the function of absorbing sound, and are widely used in fields such as automobiles, housing, and electrical products.However, as products become more sophisticated in recent years, noise environments have become more complex, and the need for sound absorption has also increased. It is becoming more sophisticated. For example, in the automobile industry, while the spread of electric vehicles has made car interiors and engine noise quieter, there is a need to reduce noise in the frequency range of 1000Hz to 6000Hz, such as motor noise and wind noise, which is said to have a lower minimum audible value for humans. It is said that
  • the present disclosure has been made in view of the above findings, and provides a sound absorbing material that exhibits excellent sound absorbing properties over a wide frequency range after 1000 Hz, which is a high frequency range, and that has reduced variation in sound absorption coefficient in the frequency range.
  • the purpose is to provide materials.
  • Layer A has three or more layers of nonwoven fabric including a first spunbond nonwoven fabric, a meltblown nonwoven fabric, and a second spunbond nonwoven fabric, and has an air permeability of 48 cc/cm 2 /sec or less;
  • a layer B having an air permeability of 20 cc/cm 2 /sec or more and 4500 cc/cm 2 /sec or less or a foam;
  • Layer C has three or more layers of nonwoven fabric including the first spunbond nonwoven fabric, the meltblown nonwoven fabric, and the second spunbond nonwoven fabric, and has an air permeability of 48 cc/cm 2 /sec or less;
  • a layer D having an air permeability of 20 cc/cm 2 /sec or more and 4500 cc/cm 2 /sec or less, a foam, or a back air layer;
  • a sound absorbing material having the following in the layer thickness direction from the incident surface side where sound enters.
  • ⁇ 2> The sum ⁇ ACmulti of the product of the air permeability and thickness of the layer A and the product of the air permeability and thickness of the layer C is 10 or more and 60 or less, and The sound absorbing material according to ⁇ 1>, wherein the sum ⁇ ACdiv of the value obtained by dividing the air permeability of the layer A by its thickness and the value obtained by dividing the air permeability of the layer C by its thickness is 50 or more and 200 or less.
  • At least one of the layer A and the layer C has four or more layers of nonwoven fabric in which a third spunbond nonwoven fabric is further laminated on the outermost surface on the incident surface side where sound enters,
  • the air permeability is 12 cc/cm 2 /sec or more and 48 cc/cm 2 /sec or less
  • the average fiber diameter of the fibers contained in the third spunbond nonwoven fabric is larger than the average fiber diameter of the fibers contained in the first spunbond nonwoven fabric and the second spunbond nonwoven fabric, and,
  • ⁇ 4> The sound absorbing material according to any one of ⁇ 1> to ⁇ 3>, wherein the layer A and the layer C have the same layer configuration.
  • ⁇ 5> The sound absorbing material according to any one of ⁇ 1> to ⁇ 4>, wherein at least one of the layer B and the layer D contains a polyester resin.
  • ⁇ 6> The sound absorbing material according to ⁇ 5>, wherein both the layer B and the layer D contain a polyester resin.
  • ⁇ 7> The sound absorbing material according to any one of ⁇ 1> to ⁇ 6>, wherein the layer D is a back air layer.
  • ⁇ 8> Any one of ⁇ 1> to ⁇ 7> above, wherein the average fiber diameter of the fibers contained in at least one of the first spunbond nonwoven fabric and the second spunbond nonwoven fabric is 8 ⁇ m or more and 30 ⁇ m or less.
  • the sound absorbing material described in item 1. ⁇ 9> The ratio of the basis weight (g/m 2 ) of the layer A or the layer C to the basis weight (g/m 2 ) of the layer B (layer A or layer C/layer B) is 0.50 or more.
  • ⁇ 10> The ratio of the air permeability (cc/cm 2 /sec) of layer A or layer C to the air permeability (cc/cm 2 /sec) of layer B (layer A or layer C/layer B) is 0. 03 or more and 1.00 or less, the sound absorbing material according to any one of ⁇ 1> to ⁇ 9> above.
  • ⁇ 11> The sound absorbing material according to any one of ⁇ 1> to ⁇ 10>, which is a sound absorbing material for automobiles.
  • ⁇ 12> The sound absorbing material according to any one of ⁇ 1> to ⁇ 11>, wherein the nonwoven fabric is a conductive nonwoven fabric formed by adhering or kneading a conductive substance.
  • the present disclosure can provide a sound absorbing material that exhibits excellent sound absorbing properties over a wide frequency range from 1000 Hz onwards, which is a high frequency range, and has reduced variations in sound absorption coefficient in the frequency range.
  • FIG. 1 is a schematic partial cross-sectional view showing an example of a layered structure of a sound absorbing material according to the present disclosure.
  • a numerical range expressed using " ⁇ " means a range that includes the numerical values written before and after " ⁇ " as lower and upper limits.
  • the upper limit or lower limit described in one numerical range may be replaced with the upper limit or lower limit of another numerical range described stepwise.
  • the upper limit or lower limit of the numerical range may be replaced with the values shown in the Examples.
  • the amount of each component in the composition refers to the total amount of the multiple substances present in the composition. means.
  • mass and weight have the same meaning
  • mass% and “weight%” have the same meaning.
  • a combination of two or more preferred embodiments is a more preferred embodiment.
  • groups (atomic groups) in the present disclosure the descriptions that do not indicate substituted or unsubstituted include those not containing a substituent as well as those containing a substituent.
  • layer includes cases where the layer is formed in the entire area when observing the area where the layer exists, as well as cases where the layer is formed only in a part of the area. Also included.
  • step is used not only to refer to an independent step but also to include the term “step” even if the step cannot be clearly distinguished from other steps as long as the intended purpose of the step is achieved.
  • unit of air permeability cc/cm 2 /sec
  • ccs the unit of air permeability
  • the sound absorbing material according to the present disclosure has a layer A having three or more layers of nonwoven fabric including a first spunbond nonwoven fabric, a meltblown nonwoven fabric, and a second spunbond nonwoven fabric, and has an air permeability of 48 cc/cm 2 /sec or less. and layer B, which is a layer or foam having an air permeability of 20 cc/cm 2 /sec to 4500 cc/cm 2 /sec, and the first spunbond nonwoven fabric, the meltblown nonwoven fabric, and the second spunbond nonwoven fabric.
  • layers having an air permeability of 20 cc/cm 2 /sec to 4500 cc/cm 2 /sec are also collectively referred to as "high air permeability layer.”
  • the sound absorbing material according to the present disclosure has the above configuration, that is, layers A and C having a predetermined air permeability, and a layer B and a layer having a predetermined air permeability, a foam, or a back air layer.
  • a sound absorbing material combining D and D exhibits excellent sound absorbing properties over a wide frequency range from 1000 Hz onwards, which is a high frequency range. Further, by forming layer A and layer C of three or more layers of nonwoven fabrics including a first spunbond nonwoven fabric, a meltblown nonwoven fabric, and a second spunbond nonwoven fabric, variations in sound absorption coefficient in the frequency range are reduced. .
  • the sound absorbing material according to the present disclosure has the above configuration, that is, layers A and C containing spunbond nonwoven fabrics having fibers that do not easily fluff are interposed alternately between layers B and D having high air permeability. Because of its structure, it also has superior abrasion resistance (sandblasting resistance), which is resistance to collisions with solid objects such as hail, graupel, and pebbles, compared to conventional sound-absorbing materials.
  • FIG. 1 shows an example of a layered structure of a sound absorbing material according to the present disclosure.
  • the sound absorbing material 10 shown in FIG. A C layer 16 having three or more layers of nonwoven fabric including a spunbond nonwoven fabric, a meltblown nonwoven fabric, and a second spunbond nonwoven fabric, and a highly air permeable D layer 18 are arranged in the layer thickness direction from the incident surface side where sound is incident. They are stacked in this order.
  • the A layer 12 and the C layer 16 may have the same or different materials, properties, and thicknesses.
  • the B layer 14 and the D layer 18 may have the same or different materials, properties, and thicknesses.
  • the values of the basis weight, thickness, air permeability, water pressure resistance, abrasion resistance, tensile strength, and average fiber diameter of the sound-absorbing material and each layer are obtained by the measuring method shown in the Examples described below.
  • the basis weight of the entire sound-absorbing material according to the present disclosure is determined from the viewpoint of improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range, and from the viewpoint of reducing workability due to increased weight of the sound-absorbing material. From the viewpoint of preventing this and ensuring the strength of the structure that supports the sound absorbing material due to weight increase, it is preferably 100 g/m 2 or more and 4000 g/m 2 or less, and 200 g/m 2 or more and 1500 g/m 2 or less. More preferably, it is 250 g/m 2 or more and 500 g/m 2 or less.
  • the basis weight of the entire sound absorbing material according to the present disclosure is preferably 250 g/m 2 or more and 400 g/m 2 or less from the viewpoint of reducing the amount of carbon dioxide discharged.
  • the basis weight (g/m 2 ) of layer A or layer C is preferably 0.05 or more, more preferably 0.70 or more, and 0.10 or more. It is more preferably 1.30 or less, and particularly preferably 0.50 or more and 1.20 or less.
  • the basis weight (g/m 2 ) of layer A or layer C is preferably 0.03 or more and 0.60 or less, more preferably 0.30 or more, and 0. It is more preferably 50 or more, and particularly preferably 0.70 or more.
  • the layer D is a layer with an air permeability of 30 cc/cm 2 /sec or more and 4500 cc/cm 2 /sec or less, or a foam, and is not a back air layer.
  • the upper limit of the above-mentioned basis weight ratio (layer A or layer C/layer D) is not particularly limited, but may be, for example, 1 or less.
  • the basis weight of layer A (g/m 2 ) and the basis weight of layer C ( g/m 2 ) (layer A/layer C) is preferably 0.10 or more and 1.50 or less, more preferably 0.30 or more, and still more preferably 0.70 or more. preferable.
  • the upper limit of the above-mentioned basis weight ratio (layer A/layer C) is not particularly limited, but may be, for example, 5.00 or less.
  • the thickness of the entire sound-absorbing material according to the present disclosure is preferably 1 mm or more and 80 mm or less, from the viewpoint of improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range. It is preferably 5 mm or more, more preferably 10 mm or more, even more preferably 30 mm or more.
  • the overall thickness of the sound absorbing material according to the present disclosure should be 100 mm or less, from the viewpoint of preventing a decrease in workability due to the increased weight of the sound absorbing material, and from the viewpoint of ensuring the strength of the structure that supports the sound absorbing material due to the increased weight. is preferable, it is more preferable that it is 80 mm or less, and it is still more preferable that it is 60 mm or less.
  • the sound absorbing material according to the present disclosure has a thickness (mm) of layer A or layer C and a thickness (mm) of layer B from the viewpoint of improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range.
  • ) (layer A or layer C/layer B) is preferably from 0.01 to 1.00, more preferably from 0.015 to 0.50, and from 0.02 to 0. More preferably, it is .10 or less.
  • the sound absorbing material according to the present disclosure has a thickness (mm) of layer A or layer C and a thickness (mm) of layer D from the viewpoint of improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range.
  • ) (layer A or layer C/layer D) is preferably from 0.01 to 1.00, more preferably from 0.015 to 0.50, and from 0.02 to 0. It is more preferably .10 or less, and particularly preferably 0.05 or more and 0.10 or less.
  • the layer D is a layer with an air permeability of 30 cc/cm 2 /sec or more and 4500 cc/cm 2 /sec or less, or a foam, and is not a back air layer.
  • the sound absorbing material according to the present disclosure has a thickness (mm) of layer A and a thickness (mm) of layer C, from the viewpoint of improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range.
  • the ratio (layer A/layer C) is preferably 0.1 or more and 5.0 or less, more preferably 0.3 or more, more preferably 0.5 or more, and 0.8 or more. It is more preferable that The upper limit of the thickness ratio (layer A/layer C) is not particularly limited, but may be, for example, 5 or less, or 3.0 or less.
  • Air permeability Layer A or Layer C/Layer B
  • the sound absorbing material according to the present disclosure improves the air permeability (cm 3 /cm 2 /sec) of layer A or layer C from the viewpoint of improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range. It is preferable that the ratio between the air permeability (cm 3 /cm 2 /sec) of layer B (air permeability: layer A or layer C/layer B) is 0.03 or more and 1.00 or less, and 0.03 It is more preferably 0.80 or less, and even more preferably 0.03 or more and 0.50 or less.
  • the sum ⁇ ACmulti of the product of the air permeability and thickness of layer A and the product of air permeability and thickness of layer C improves sound absorption over a wide frequency range and has a sound absorption coefficient in the frequency range.
  • it is preferably 10 or more and 60 or less, and more preferably 20 or more and 40 or less.
  • ⁇ ACmulti is preferably 10 or more, more preferably 15 or more, and even more preferably 20 or more.
  • ⁇ ACmulti is preferably 60 or less, more preferably 50 or less, and even more preferably 40 or less.
  • ⁇ ACmulti is the sum of the product of the air permeability (cc/cm 2 /sec) and thickness (mm) of layer A and the product of the air permeability (cc/cm 2 /sec) and thickness (mm) of layer C. This is an indicator of how much resistance is actually received from the fibers when sound is incident. When this index falls within the above range, the sound absorption coefficient near 1000 Hz tends to be better.
  • the sum ⁇ ACdiv of the value obtained by dividing the air permeability of the layer A by the thickness and the value obtained by dividing the air permeability of the layer C by the thickness improves the sound absorbing property over a wide frequency range and From the viewpoint of further reducing variations in sound absorption coefficient in the frequency domain, it is preferably 40 or more and 200 or less, more preferably 50 or more and 200 or less, and even more preferably 60 or more and 120 or less. From the same viewpoint as above, ⁇ ACdiv is preferably 40 or more, more preferably 50 or more, and even more preferably 60 or more. From the same viewpoint as above, ⁇ ACdiv is preferably 200 or less, more preferably 150 or less, and even more preferably 120 or less.
  • the sound absorbing material according to the present disclosure is a product of the air permeability and thickness of layer A, the air permeability and thickness of layer C, and
  • the sum ⁇ ACmulti of the product of the thicknesses is 10 or more and 60 or less, and the sum ⁇ ACdiv of the value obtained by dividing the air permeability of layer A by the thickness and the value obtained by dividing the air permeability of the layer C by the thickness is 50 or more and 200. It is preferable that it is below.
  • ⁇ ACdiv is the value obtained by dividing the air permeability (cc/cm 2 /sec) of layer A by the thickness (mm) and the value obtained by dividing the air permeability (cc/cm 2 /sec) of layer C by the thickness (mm). It is the sum of and, and indicates the magnitude of the interaction between the fiber and its space when sound is incident. When this index falls within the above range, the sound absorption coefficient near 5000 Hz tends to be better.
  • At least one of layer B and layer D has an air permeability of 30 cc, from the viewpoint of improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range.
  • /cm 2 /sec or more and 4,500 cc/cm 2 /sec or less and both layers B and D have air permeability of 30 cc/cm 2 /sec or more and 4,500 cc/cm 2 /sec or less. More preferably, it is a layer.
  • the sound absorbing material according to the present disclosure from the viewpoint of improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range, it is preferable that at least one of layer B and layer D contains a polyester resin. It is more preferable that both layers B and D contain polyester resin.
  • the nonwoven fabric included in the sound absorbing material according to the present disclosure may be a conductive nonwoven fabric to which a conductive substance is attached or kneaded.
  • the nonwoven fabric is a conductive nonwoven fabric, electromagnetic wave absorption performance can be obtained.
  • the nonwoven fabric refers not only to the nonwoven fabric that layer A and layer C have (for example, a first spunbond nonwoven fabric, meltblown nonwoven fabric, and second spunbond nonwoven fabric), but also layer B and layer D that have a predetermined air permeability. It may also be applied when made of non-woven fabric.
  • the conductive nonwoven fabric can be produced by, for example, attaching or kneading a conductive substance to at least one of a first spunbond nonwoven fabric, a meltblown nonwoven fabric, and a second spunbond nonwoven fabric. can do.
  • the nonwoven fabric Preferred embodiments of the nonwoven fabric are as described below.
  • the conductive substance include conductive polymers, carbon black, graphite, acetylene black, metals, soft magnetic metals, stearic acid monoglyceride, etc. From the viewpoint of electromagnetic wave absorption performance, it is preferable to include conductive polymers. .
  • the conductive substance may be attached to at least a portion of the fibers constituting the nonwoven fabric.
  • the adhesion of the conductive substance is characterized in that the conductive polymer is attached only to the fibers on the surface of the nonwoven fabric (i.e., the part that is visible from the outside of the nonwoven fabric; the same applies hereinafter), and the conductive polymer is attached to the fibers inside the nonwoven fabric.
  • the conductive polymer may be attached only to the surface of the nonwoven fabric, or the conductive polymer may be attached to both the fibers on the surface of the nonwoven fabric and the fibers inside the nonwoven fabric.
  • the type of conductive polymer is not particularly limited, but for example, poly-3,4-ethylenedioxythiophene (hereinafter also referred to as "PEDOT"), PEDOT and poly-4-styrene sulfanate (hereinafter also referred to as "PSS”), etc.
  • PEDOT-PSS polypyrrole, polythiophene, polyacetylene, polyaniline, etc. doped with Among the above, the conductive polymer preferably contains at least one of PEDOT and PEDOT-PSS, and more preferably contains PEDOT-PSS, from the viewpoint of electromagnetic wave absorption performance.
  • PEDOT-PSS for example, PEDOT-PSS described in International Publication No. 2013/073673 can be used.
  • a liquid containing a conductive substance (more preferably a conductive polymer) is applied to the nonwoven fabric to form the conductive nonwoven fabric.
  • the manufacturing method may include an attachment step of attaching a conductive substance.
  • the coating method is not particularly limited, and may be any known coating method such as dipping coating (for example, dip coating), spray coating (for example, spray coating), spin coating (for example, spin coating), slit coating, curtain coating, gravure coating, flexo coating, etc. can be adopted.
  • the method for manufacturing a conductive nonwoven fabric may further include a drying step of drying a liquid containing a conductive substance applied to the nonwoven fabric.
  • the drying means in the drying step is not particularly limited, and can be carried out by known methods such as drying by blowing air, drying by heating, or a combination thereof.
  • the method for manufacturing the conductive nonwoven fabric may be such that the coating step and drying step are repeated multiple times.
  • the liquid containing the conductive substance may be either a solution or dispersion in which the conductive substance is dissolved, but from the viewpoint of attaching the conductive substance to the nonwoven fabric with high uniformity, a solution in which the conductive substance is dissolved is preferred. is preferred.
  • solvents for liquids containing conductive substances include water, ethanol, propyl alcohol, and the like. The solvents may be used alone or in combination of two or more.
  • the liquid containing the conductive substance may contain a binder resin in order to improve the fixability and stability of the conductive substance on the surface of the nonwoven fabric.
  • binder resin examples include olefin resins, polyester resins, acrylic resins, polyurethane resins, polyvinyl acetate resins, vinylidene chloride resins, vinyl chloride resins, polyamide resins, polyimide resins, styrene resins, Examples include, but are not limited to, fluororesin-based, silicone resin-based, epoxy resin-based, phenol resin-based, aliphatic ester-based, and aliphatic ether-based resin compounds.
  • the content of the conductive substance in the entire liquid containing the conductive substance is preferably 0.1% by mass to 10.0% by mass, more preferably 0.2% by mass to 5.0% by mass.
  • Layer A has three or more layers of nonwoven fabric including a first spunbond nonwoven fabric, a meltblown nonwoven fabric, and a second spunbond nonwoven fabric, and has an air permeability of 48 cc/cm 2 /sec or less.
  • ⁇ Layer A Layer configuration
  • the layer configuration of Layer A only needs to have three or more layers of nonwoven fabrics including a first spunbond nonwoven fabric, a meltblown nonwoven fabric, and a second spunbond nonwoven fabric, and the lamination order etc.
  • the configuration is not particularly limited. Since spunbond nonwoven fabric has sufficient surface strength, there is a low possibility that the front and back sides of the nonwoven fabric will be torn by sharp objects. Its own strength, installation strength, water resistance, etc. are likely to be suppressed.
  • the layer structure of layer A has a third layer on the outermost surface on the incident surface side where sound enters. It is preferable that the spunbond nonwoven fabric has four or more layers of nonwoven fabric further laminated.
  • Examples of the layer structure of layer A include (1) to (4) below, but the first embodiment is not limited thereto.
  • Layer A having three layers of nonwoven fabric including a first spunbond nonwoven fabric, a meltblown nonwoven fabric, and a second spunbond nonwoven fabric in this order in the layer thickness direction from the incident surface side where sound is incident also known as SMS layer structure.
  • Layer A also known as SSM layer structure
  • Layer A having three layers of nonwoven fabric including a first spunbond nonwoven fabric, a second spunbond nonwoven fabric, and a meltblown nonwoven fabric in this order in the layer thickness direction from the incident surface side where sound is incident.
  • Layer A (also known as MSS layer structure) having three layers of nonwoven fabric including a meltblown nonwoven fabric, a first spunbond nonwoven fabric, and a second spunbond nonwoven fabric in this order in the layer thickness direction from the incident surface side where sound is incident. ).
  • a three-layer nonwoven fabric including a third spunbond nonwoven fabric, a first spunbond nonwoven fabric, a meltblown nonwoven fabric, and a second spunbond nonwoven fabric in this order in the layer thickness direction from the incident surface side where sound is incident.
  • Layer A (also referred to as SSMS layer configuration).
  • Layer A and layer C may have the same or different air permeability.
  • Layer A and layer C may have the same or different thicknesses.
  • Layer A and layer C may be made of the same material or may be made of different materials.
  • the fact that the materials of layer A and layer C are different means that the component compositions contained in the materials are different. For example, when at least one selected from the group consisting of the type and amount of resin contained in the material, the presence or absence of a filler, and, if a filler is included, the type and amount of filler, layer A and layer C are different. It is assumed that the materials are different.
  • the layer A and the layer C have the same layer configuration from the viewpoint of improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range.
  • the same layer structure refers to three or more layers of nonwoven fabric including a first spunbond nonwoven fabric, a meltblown nonwoven fabric, and a second spunbond nonwoven fabric (four or more layers if a third spunbond nonwoven fabric is included). ), the lamination order, basis weight, air permeability, material, thickness, etc. of each nonwoven fabric are the same.
  • layer A has four or more layers of nonwoven fabric in which a third spunbond nonwoven fabric is further laminated on the outermost surface on the side of the incident surface where sound enters, and has an air permeability of 12 cc/cm 2 /sec or more. 48 cc/cm 2 /sec or less, and the average fiber diameter of the fibers contained in the third spunbond nonwoven fabric is larger than the average fiber diameter of the fibers contained in the first spunbond nonwoven fabric and the second spunbond nonwoven fabric. In addition, it is preferable that the average fiber diameter of the fibers contained in the third spunbond nonwoven fabric is 20 ⁇ m or more and 50 ⁇ m or less.
  • the first spunbond nonwoven fabric, the second spunbond nonwoven fabric, and the third spunbond nonwoven fabric may be the same spunbond nonwoven fabric, or may be different spunbond nonwoven fabrics.
  • the same spunbond nonwoven fabrics mean that the component compositions contained in the nonwoven fabrics are the same. For example, if a first spunbond nonwoven fabric and a second spunbond nonwoven fabric are the same in terms of the type and amount of resin contained in the material, the basis weight, the fiber diameter of the fibers contained in the nonwoven fabric, etc.
  • the first spunbond nonwoven fabric and the second spunbond nonwoven fabric are considered to be the same.
  • Layer A may include other nonwoven fabrics (hereinafter also referred to as "other nonwoven fabrics") other than spunbond nonwoven fabrics and meltblown nonwoven fabrics.
  • Other nonwoven fabrics include, for example, needle punched nonwoven fabrics, thermal bonded nonwoven fabrics, chemical bonded nonwoven fabrics, stitch bonded nonwoven fabrics, spunlace nonwoven fabrics, and the like.
  • the nonwoven fabric may be a long fiber nonwoven fabric, a short fiber nonwoven fabric, or a mixture of both.
  • the fibers contained in the nonwoven fabric may be single fibers, side-by-side type or core-sheath type composite fibers, or crimped fibers. In the case of a single fiber, it may contain multiple resins. Further, the cross-sectional shape of the fibers may be not only round but also irregular, such as a V-shape, a cross-shape, and a T-shape.
  • the nonwoven fabric may include a plurality of fibers having different average fiber diameters.
  • the nonwoven fabric may include a plurality of fibers having different average fiber lengths.
  • the nonwoven fabric may include a plurality of fibers having different average fiber diameters and average fiber lengths.
  • the fibers contained in the nonwoven fabric can contain thermoplastic resin.
  • Thermoplastic resins are not particularly limited, and include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 3-methyl-1-butene, 3-methyl-1-pentene, and 3-ethyl- Homopolymers or copolymers of ⁇ -olefins such as 1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene; polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate, polyhexamethylene Polyester resins such as terephthalate; polyamides such as nylon-6, nylon-66, and polymethaxylene adipamide; polyvinyl chloride, polyimide, ethylene/vinyl acetate copolymers; polyacrylonitrile; polycarbonate; polystyrene; ionomer; hyperbranched Examples include polyolefin
  • Examples of ⁇ -olefin homopolymers or copolymers include ethylene/propylene random copolymers, high-pressure low-density polyethylene, linear low-density polyethylene (LLDPE), high-density polyethylene, and ethylene/1-butene random copolymers.
  • Ethylene-based polymers such as ethylene random copolymers; propylene-based polymers (including biomass-derived propylene-based polymers); poly-1-butene, poly-4-methyl-1-pentene, and the like.
  • the thermoplastic resin preferably contains at least one selected from the group consisting of high-pressure low-density polyethylene, linear low-density polyethylene (LLDPE), high-density polyethylene, propylene-based polymers, polyethylene terephthalate, and polyamide.
  • the thermoplastic resin preferably contains a propylene-based polymer from the viewpoint of further improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range.
  • the nonwoven fabric has the advantage of further improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range, and facilitates physical compression bonding of layers A to D using ultrasonic welding or radiant heat.
  • a propylene-based polymer is included from the viewpoint of making the resin more durable and lightweight as a resin.
  • propylene-based polymers examples include propylene homopolymers, propylene random copolymers that are copolymers of propylene as a main component and one or more ⁇ -olefins as subcomponents, among others. , propylene homopolymer is preferred.
  • the content of structural units derived from ⁇ -olefin is preferably 1 mol% to 10 mol% of the total, more preferably 1 mol% to 5 mol% of the total. .
  • the ⁇ -olefin used in the copolymerization of the propylene random copolymer is preferably an ⁇ -olefin having 2 or more carbon atoms (excluding propylene), and more preferably an ⁇ -olefin having 2 or 4 to 8 carbon atoms.
  • ⁇ -olefins include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1 -pentene, 4-methyl-1-pentene, 4-methyl-1-hexene and the like are preferred.
  • the propylene polymer may be a biomass-derived propylene polymer.
  • Biomass-derived propylene polymer refers to a propylene polymer (A) produced from a raw material monomer containing biomass-derived propylene. Since the biomass-derived propylene-based polymer is a carbon-neutral material, it is possible to reduce the environmental load in manufacturing the nonwoven fabric laminate.
  • a monomer containing biomass-derived propylene, which is a raw material for a biomass-derived propylene polymer, can be obtained by cracking biomass naphtha or synthesizing it from biomass-derived ethylene.
  • the biomass-derived propylene-based polymer can be obtained by polymerizing the biomass-derived propylene-containing monomer synthesized in this manner by the same method as in the case of using conventionally known petroleum-derived propylene.
  • a propylene polymer synthesized using a bio-derived propylene-containing monomer as a raw material is a biomass-derived propylene polymer.
  • the content of the bio-derived propylene polymer in the raw material monomer is more than 0% by mass, may be 100% by mass, or less than 0% by mass based on the total amount of the raw material monomer.
  • Monomers that are raw materials for biomass-derived propylene polymers include bio-derived propylene, propylene derived from fossil fuels such as petroleum, and/or ⁇ -olefins other than ethylene and propylene (1-butene, 1-hexene, etc.) It may further include.
  • Biomass-derived propylene polymers are produced using methanol-to-olefins (MTO) or methanol using gas generated by thermally decomposing Empty Fruit Bunches (EFB) such as coconut shells. It can also be obtained by polymerizing propylene obtained by synthesis of propylene (MTP: Methanol-to-Propylene).
  • biomass-derived propylene polymers can also be obtained by polymerizing propylene obtained by dehydrating isopropanol produced by fermentation from biomass raw materials mainly composed of inedible plants such as sorghum.
  • the content of radioactive carbon (C14) in a monomer such as propylene used as a raw material is P C14
  • the content of biomass-derived carbon in the raw material Pbio (%) can be calculated by the following formula.
  • Formula (2): Pbio(%) P C14 /105.5 ⁇ 100 That is, if all the raw materials for the propylene polymer are derived from biomass, the content of biomass-derived carbon is theoretically 100%. Therefore, the biomass degree of the biomass-derived propylene polymer is 100%.
  • biomass degree of the union indicates the content rate of carbon derived from biomass, and is calculated by measuring radioactive carbon (C14).
  • C14 radioactive carbon
  • Carbon dioxide in the atmosphere contains C14 at a constant rate (for example, about 105.5 pMC). Therefore, it is known that the C14 content in plants (for example, corn) that grow by taking in carbon dioxide from the atmosphere is about 105.5 pMC. It is also known that fossil fuels contain almost no C14.
  • Recycled polymer includes a polymer obtained by recycling waste polymer products, and can be produced, for example, by the method described in West German Patent Application No. 102019127827.
  • the recycled polymer may include a marker that allows it to be identified as having been obtained through recycling.
  • the melting point (Tm) of the propylene polymer is preferably 155°C or higher, more preferably 157°C to 165°C.
  • the melting point can be measured by known methods using differential scanning calorimetry (DSC).
  • the fibers contained in the nonwoven fabric constituting layer A preferably contain 93.0% by mass to 100% by mass, and preferably 94.0% to 99.5% by mass of thermoplastic resin, based on the total amount of the nonwoven fabric. More preferred. Furthermore, the fibers contained in the nonwoven fabric according to the present disclosure preferably contain 70.0% to 100% by mass, and preferably 90.0% to 99.5% by mass of a propylene polymer based on the total amount of the nonwoven fabric. It is more preferable.
  • the fibers contained in the nonwoven fabric constituting layer A may contain commonly used additives, if necessary.
  • additives include charging agents, antistatic agents, absorbent particles, nanoparticles, ion exchange resins, deodorants, fragrances, adhesives, surface modifiers, biocides, antibacterial agents, and antiviral agents.
  • Various known additives such as additives, flame retardants, stabilizers, antioxidants, weather-resistant stabilizers, heat-resistant stabilizers, light-resistant stabilizers, antifogging agents, lubricants, conductive materials, dyes, pigments, natural oils, synthetic oils, waxes, etc. Examples include agents.
  • the nonwoven fabric constituting layer A can be manufactured using a known nonwoven fabric molding machine.
  • spunbond nonwoven fabric is produced by melting a thermoplastic resin as a raw material using an extruder, discharging the molten composition from multiple spinnerets, and cooling and stretching the fibrous resin as necessary. After that, it can be manufactured by depositing it on the collection surface and subjecting it to heat and pressure treatment using an embossing roll.
  • melt-blown nonwoven fabrics are produced by melting a thermoplastic resin as a raw material, discharging it from a spinning nozzle, pulling it with high-temperature, high-pressure gas, and capturing the fine fibers in a collector such as a perforated belt or a perforated drum. It can be manufactured by collecting and depositing.
  • the air permeability of Layer A is 48 cc/cm 2 /sec or less. Further, from the viewpoint of exhibiting excellent sound absorption properties in a wide frequency range and reducing variations in sound absorption coefficient, the air permeability is preferably 10 cc/cm 2 /sec to 42 cc/cm 2 /sec, and 11 cc/cm 2 /sec to 42 cc/cm 2 /sec. /cm 2 /sec or more and 35 cc/cm 2 /sec or less, more preferably 12 cc/cm 2 /sec or more and 32 cc/cm 2 /sec or less.
  • the air permeability of layer A is preferably 1 cc/cm 2 /sec or more, more preferably 3 cc/cm 2 /sec or more, and 10 cc/cm 2 /sec or more. It is more preferable that it be at least 12 cc/cm 2 /sec, particularly preferably 12 cc/cm 2 /sec or more.
  • the air permeability of layer A can be controlled, for example, by adjusting the type of nonwoven fabric, the thickness of the layer, the basis weight, the fiber diameter, etc.
  • ⁇ Layer A Average fiber diameter Layer A has a viewpoint that the average fiber diameter of the fibers contained in the nonwoven fabric constituting layer A improves sound absorption over a wide frequency range and further reduces variations in sound absorption coefficient in the frequency range. Therefore, it is preferably small (that is, the fibers are thin), more specifically, 10 ⁇ m or more and 100 ⁇ m or less, and the average fiber diameter of the surface on the incident surface side where sound enters (hereinafter also referred to as "surface average fiber diameter"). is more preferably 20 ⁇ m or more and 100 ⁇ m or less, and even more preferably 30 ⁇ m or more and 50 ⁇ m or less. When the average fiber diameter is equal to or greater than the lower limit, the mechanical properties of the laminate deteriorate, and a decrease in the laminate thickness during compression processing is suppressed.
  • the average fiber diameter of layer A is preferably smaller than the average fiber diameter of the fibers constituting the nonwoven fabric of these layers.
  • the average fiber diameter of the fibers contained in the first spunbond nonwoven fabric, the second spunbond nonwoven fabric, and the third spunbond nonwoven fabric is not particularly limited, it is possible to improve sound absorption over a wide frequency range and to absorb sound in the frequency range. From the viewpoint of further reducing the variation in ratio, the diameter is preferably larger than the average fiber diameter of the fibers contained in the meltblown nonwoven fabric.
  • the average fiber diameter of the fibers constituting the first and second spunbond nonwoven fabrics is preferably 8 ⁇ m or more and 30 ⁇ m or less, and 8 ⁇ m or more and 25 ⁇ m or less, from the viewpoint of further reducing variations in sound absorption coefficient in a wide frequency range. It is more preferable.
  • the average fiber diameter of the fibers constituting the first and second spunbond nonwoven fabrics of layer A is smaller than the average fiber diameter of the fibers constituting the nonwoven fabrics of these layers. Preferably small.
  • the average fiber diameter (surface average fiber diameter) of the fibers contained in the third spunbond nonwoven fabric of layer A is preferably relatively large from the viewpoint of sandblasting resistance (abrasion resistance), and is 20 ⁇ m or more and 100 ⁇ m or less. is preferable,
  • the average fiber diameter of the fibers constituting the melt-blown nonwoven fabric is 0.5 ⁇ m or more, or 1 ⁇ m or more and 4 ⁇ m or less, from the viewpoint of improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range. It is preferable that there be.
  • the embossing roll may be set at a temperature in the range of 140°C to 170°C, and the mirror roll may be set at a temperature in the range of 140°C to 170°C.
  • embossing for example, thermocompression bonding
  • the mirror roll may be set at a temperature in the range of 140°C to 170°C.
  • the basis weight of layer A is preferably 30 g/m 2 or more and 230 g/m 2 or less, from the viewpoint of exhibiting excellent sound absorption properties in a wide frequency range and reducing variations in sound absorption coefficient. More preferably, it is 40 g/m 2 or more and 180 g/m 2 or less. From the viewpoint of maintaining sandblasting resistance, the basis weight of the spunbond layer on the side of the entrance surface where the sound enters layer A is preferably 20 g/m 2 or more and 200 g/m 2 or less, and 30 g/m 2 or more and 150 g/m 2 or less. It is more preferably 2 or less, and even more preferably 90 g/m 2 or more and 150 g/m 2 or less.
  • the basis weight can be controlled by adjusting the layer thickness, fiber diameter, etc., for example.
  • the thickness of layer A is preferably 0.1 mm or more and 1.5 mm or less, or 0.3 mm or more and 1.0 mm or less.
  • Layer B is a layer or foam having an air permeability of 20 cc/cm 2 /sec or more and 4500 cc/cm 2 /sec or less.
  • Layer B may be a single layer or a laminate of two or more layers.
  • the material of layer B is not particularly limited as long as it is a material or foam whose air permeability falls within the above range.
  • Examples of the material of layer B include sheet-like materials such as nonwoven fabric, resin molding having a three-dimensional network structure, porous film, paper, woven fabric, knitted fabric, felt, and inorganic fiber.
  • Nonwoven fabric may be a long fiber nonwoven fabric, a short fiber nonwoven fabric, or a mixed fiber fabric.
  • the fibers contained in the nonwoven fabric may be single fibers, side-by-side type or core-sheath type composite fibers, or crimped fibers. In the case of a single fiber, it may contain multiple resins. Further, the cross-sectional shape of the fibers may be not only round but also irregular, such as a V-shape, a cross-shape, and a T-shape.
  • the nonwoven fabric may include a plurality of fibers having different average fiber diameters.
  • the nonwoven fabric may include a plurality of fibers having different average fiber lengths.
  • the nonwoven fabric may include a plurality of fibers having different average fiber diameters and average fiber lengths.
  • the fibers contained in the nonwoven fabric contain a thermoplastic resin.
  • the thermoplastic resin include the thermoplastic resins exemplified for layer A described above.
  • the thermoplastic resin may be composed of one type or a mixture of two or more types.
  • the thermoplastic resin more preferably contains at least one of a polyester resin and an olefin polymer, from the viewpoint of improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range. It is preferable to contain a resin, more preferably to contain both a polyester resin and an olefin polymer, and particularly preferably to contain both a polyester resin and a propylene polymer.
  • the polyester resin includes, for example, a polyester homopolymer resin and a polyester copolymer resin.
  • Polyester resins especially polyester resins that include polyester copolymer resins and various low-melting binder resins such as acrylic resins, urethane resins, polyamide resins, and olefin resins
  • acrylic resins urethane resins
  • polyamide resins polyamide resins
  • olefin resins olefin resins
  • the olefin polymer preferably contains at least one of a propylene polymer and an ethylene polymer.
  • the nonwoven fabric constituting at least one of layer B or layer D can be formed by forming layer A, layer B, layer C, and layer D, and then bonding the resulting layers. is likely to become easy.
  • layer A which is preferable because it facilitates bonding between layer C and layers B and D, which are high air permeability layers.
  • the fibers constituting layer B may, for example, consist only of fibers of polyester resin (more preferably polyethylene terephthalate resin), and may further include fibers of propylene polymer.
  • polyester resin more preferably polyethylene terephthalate resin
  • fibers of propylene polymer sound absorption properties can be more easily improved over a wide frequency range, and variations in sound absorption coefficient in the frequency range can also be reduced. more easily reduced. Further, it is preferable because the bulkiness can be easily adjusted, thereby making it easy to adjust the air permeability of layer B to a range of 20 cc/cm 2 /sec to 4500 cc/cm 2 /sec.
  • a nonwoven fabric layer as layer B When employing a nonwoven fabric layer as layer B, a nonwoven fabric composed of short fibers of polyester resin, a nonwoven fabric containing both short fibers of polyester resin and short fibers of propylene polymer, etc. can be used.
  • the short fibers of polyester resin and short fibers of propylene polymer may be manufactured by a known melt spinning method, or commercially available ones may be used.
  • As short fibers of polyester resin for example, those having an average fiber length in the range of 10 mm to 100 mm and an average fiber diameter in the range of 10 ⁇ m to 70 ⁇ m can be used.
  • the propylene-based polymer short fibers can have, for example, an average fiber length in the range of 10 mm to 100 mm and an average fiber diameter in the range of 10 ⁇ m to 50 ⁇ m.
  • the proportion of short fibers of polyester resin and short fibers of propylene polymer in the entire nonwoven fabric constituting layer B is determined based on mass: short fibers of polyester resin: short fibers of propylene polymer
  • the short fiber ratio of the polymer is preferably in the range of 99:1 to 5:95, more preferably in the range of 95:5 to 10:90, and preferably in the range of 80:20 to 20:80. More preferred.
  • polyethylene terephthalate resin When using a polyethylene terephthalate resin as the polyester resin, a copolymer of a polyhydric alcohol such as ethylene glycol and a dibasic acid such as terephthalic acid can be used as the polyethylene terephthalate resin.
  • polyethylene terephthalate-based resins include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), polyethylene isophthalate (PEI), and polybutylene isophthalate.
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PEN polyethylene naphthalate
  • PBN polybutylene naphthalate
  • PEI polyethylene isophthalate
  • PBI polyhexamethylene terephthalate
  • PHI polyhexamethylene isophthalate
  • PN polyhexamethylene naphthalate
  • the propylene-based polymer may be a homopolymer of propylene, or a copolymer of propylene and another ⁇ -olefin that can be copolymerized.
  • the ⁇ -olefin include ⁇ -olefins having 2 or more carbon atoms, preferably 2 to 8 carbon atoms, such as ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methyl-1-pentene. I can do it.
  • the propylene polymer is a copolymer of propylene and an ⁇ -olefin, it may be a copolymer with one or more ⁇ -olefins selected from ⁇ -olefins.
  • MFR melt flow rate
  • the nonwoven fabric is preferably composed of fibers made of two or more components: a low melting point resin and a high melting point resin.
  • a low melting point resin preferably conjugate fibers of low melting point polyester resin/high melting point polyester resin (preferably core-sheath structure type, side-by-side type conjugate fibers, etc.) can be mentioned.
  • the nonwoven fabric contains fibers of high melting point polyester resin, the shape retention of the nonwoven fabric can be controlled.
  • fibers of low melting point polyester resin and exposing them to the fiber surface it is easy to join the obtained layers after forming layer A, layer B, layer C, and layer D, respectively. It's easy.
  • the melting point of the low melting point polyester resin is preferably 130 or less, more preferably 120 or less.
  • the lower limit is not particularly limited, but may be, for example, 70°C or higher.
  • the melting point of the high melting point polyester resin is not particularly limited as long as it is higher than the melting point of the low melting point polyester resin, but may be, for example, 200°C or higher, or 220°C or higher.
  • the fibers contained in the nonwoven fabric constituting layer B may further include binder fibers from the viewpoint of bonding between the fibers constituting the nonwoven fabric, between each layer, and from the viewpoint of controlling the shape retention of layer B.
  • the binder fiber is a fiber for binding between the fibers constituting layer B and between each layer.
  • binder fibers examples include propylene polymer short fibers, low melting point ethylene polymer fibers, low melting point polyester resin fibers, and low melting point multibranched polyolefin fibers (for example, fibers made by Mitsui Chemicals, Inc.).
  • SWP (registered trademark)
  • acrylic fibers composite fibers of low melting point polyester resin/high melting point polyester resin (preferably core-sheath structure type, side-by-side type composite fibers, etc.), propylene polymer/ethylene polymer Combined composite fibers (preferably core-sheath structure type, side-by-side type composite fibers, etc.), ethylene polymer/polyester resin composite fibers (preferably core-sheath structure type, side-by-side type composite fibers, etc.), etc. .
  • the resin constituting the binder fibers may be a synthetic product or a commercially available product.
  • An example of a commercially available product is Melty 4080 (manufactured by Unitika Co., Ltd.).
  • the binder fibers may be obtained, for example, by applying a solution containing a binder component (for example, a fibrous emulsion, etc.) by spray coating during the preparation of layer B, and heat-treating the coated film.
  • a binder component for example, a fibrous emulsion, etc.
  • the binder component preferably contains an acrylic resin emulsion (for example, Boncoat AN-1170 manufactured by DIC Corporation).
  • examples of the binder component include urethane resins, polyamide resins, olefin resins, and the like.
  • the binder short fibers of polyester resin may be those comprising, for example, polyethylene terephthalate in the core and a binder component in the sheath.
  • the binder component include copolymerized polyesters made of acrylic, terephthalic acid or its ester-forming derivatives, isophthalic acid or its ester-forming derivatives, lower alcohols, polyalkylene glycols, or monoethers thereof.
  • the nonwoven fabric constituting layer B contains, for example, 1% to 95% by mass (preferably 1% to 60% by mass) of short fibers of the propylene polymer, and 99% to 5% by mass of short fibers of the propylene polymer. (preferably 40% to 5% by mass) of polyester resin binder short fibers (preferably polyethylene terephthalate resin short fibers) and formed a web using a spreader or carding machine. The web is laminated in multiple layers using a cross-layer machine, and treated with a hot air treatment machine set at a predetermined gap distance to fuse the binder short fibers of the polyester resin and the short fibers of the propylene polymer. It can be obtained by a coating process.
  • polyester resin binder short fibers preferably polyethylene terephthalate resin short fibers
  • the binder short fibers of the polyester resin may have, for example, polyethylene terephthalate in the core and a binder component in the sheath.
  • the binder component include copolymerized polyesters made of acrylic, terephthalic acid or its ester-forming derivatives, isophthalic acid or its ester-forming derivatives, lower alcohols, polyalkylene glycols, or monoethers thereof.
  • the fibers contained in the nonwoven fabric constituting layer B may contain commonly used additives, if necessary.
  • additives include charging agents, antistatic agents, absorbent particles, nanoparticles, ion exchange resins, deodorants, fragrances, adhesives, surface modifiers, biocides, antibacterial agents, and antiviral agents.
  • Various known additives such as additives, flame retardants, stabilizers, antioxidants, weather-resistant stabilizers, heat-resistant stabilizers, light-resistant stabilizers, antifogging agents, lubricants, conductive materials, dyes, pigments, natural oils, synthetic oils, waxes, etc. Examples include agents.
  • the method for producing the nonwoven fabric is not particularly limited, and known methods can be applied.
  • the fibers may be mechanically joined by needle punching or fused by heat treatment.
  • the resin molded body having a three-dimensional network structure examples include a resin molded body formed by molding a resin composition containing the aforementioned thermoplastic resin into a three-dimensional network shape, and more preferably ethylene. Examples include resin molded articles formed by molding a resin composition containing either a polymer or a propylene polymer into a three-dimensional network shape. Note that the resin molded body having a three-dimensional network structure refers to a resin molded body having a three-dimensional network structure.
  • Porous films include microporous membranes, mesoporous membranes, and the like.
  • Porous films include, for example, resin porous films such as films made porous by stretching resin containing fillers or phase-separated polymer alloys, inorganic porous films such as cement porous films, and films with holes made by processing such as needle punching. Examples of such films include The air permeability of the porous film can be controlled, for example, by adjusting the thickness, density, pore diameter, etc.
  • inorganic fibers examples include glass fibers and carbon fibers.
  • foam examples include rubber foam, polyolefin foam (eg, polyethylene foam, polypropylene foam, etc.), polyurethane foam, polystyrene foam, acrylic copolymer foam, and the like.
  • the air permeability of the foam can be controlled, for example, by adjusting the thickness, density, closed cell ratio, etc.
  • the foam preferably has an open cell structure from the viewpoint of increasing the air permeability of the high air permeability layer and the sound absorbing property of the sound absorbing material.
  • the density of the foam is preferably 9 kg/m 3 or more and 200 kg/m 3 or less, more preferably 10 kg/m 3 or more and 200 kg/m 3 or less, and 20 kg/m 3 or more and 200 kg/m 3 or less. It is even more preferable that there be.
  • the density of the foam is measured in accordance with ASTM D792 method A (underwater displacement method).
  • the closed cell ratio of the foam is preferably 0% or more and less than 60%, more preferably 0% or more and 55% or less, and even more preferably 0% or more and 50% or less.
  • the closed cell ratio of the foam is measured according to method C of ASTM D2856.
  • the average diameter of the cells in the foam is preferably 10 ⁇ m or more and 2000 ⁇ m or less, more preferably 300 ⁇ m or more and 2000 ⁇ m or less, and even more preferably 600 ⁇ m or more and 2000 ⁇ m or less.
  • ⁇ Layer B Air permeability
  • Layer B is a layer or foam with an air permeability of 20 cc/cm 2 /sec to 4500 cc/cm 2 /sec, exhibits superior sound absorption in a wide frequency range, and has a high sound absorption coefficient. From the viewpoint of further reducing variations in the thickness, the layer is preferably 25 cc/cm 2 /sec or more, more preferably the layer is 30 cc/cm 2 /sec or more, and the layer is 50 cm 3 /cm 2 /sec or more.
  • the air permeability of layer B is preferably 4500 cm 3 /cm 2 /sec or less, more preferably 1000 cm 3 /cm 2 /sec or less, and 600 cm 3 /cm 2 /sec or less from the viewpoint of strength etc. It is more preferable that
  • the air permeability of layer B can be determined, for example, by adjusting the thickness and basis weight of the layer; by making the material of layer B a nonwoven fabric and adjusting the fiber diameter, fiber length, resin contained in the fiber (preferably polyester resin), etc. ; etc. can be controlled. It can also be controlled by adjusting the porosity and the like through post-processing such as calendering.
  • ⁇ Layer B average fiber diameter
  • the fiber diameter of the fibers included in layer B exhibits excellent sound absorption properties in a wide frequency range and has a variation in sound absorption coefficient.
  • the thickness is preferably 10 ⁇ m or more and 100 ⁇ m or less, 10 ⁇ m or more and 70 ⁇ m or less, 10 ⁇ m or more and 50 ⁇ m or less, 15 ⁇ m or more and 45 ⁇ m or less, or 20 ⁇ m or more and 40 ⁇ m or less.
  • the average fiber diameter of layer B is calculated from all fibers contained in layer B. That is, when layer B is composed of a nonwoven fabric containing fibers of one type of thermoplastic resin, the "average fiber diameter of layer B" refers to the average fiber diameter of the fibers of one type of thermoplastic resin. . When layer B is composed of a nonwoven fabric containing fibers of two or more types of thermoplastic resins, it means the arithmetic average value of the fiber diameters of all the fibers in which the two or more types of thermoplastic resins are mixed.
  • layer B When layer B is composed of a nonwoven fabric containing a plurality of fibers with different fiber diameters, it means the arithmetic average value of the fiber diameters of all the fibers in which the plurality of fibers with different fiber diameters are mixed. There are no particular limitations on the method for keeping the average fiber diameter of layer B within a desired range. It can be controlled in the same way as the average fiber diameter of layer A.
  • ⁇ Layer B basis weight
  • the basis weight of layer B is determined from the viewpoints of improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range, and preventing a decrease in workability due to an increase in the weight of the sound absorbing material. From this point of view, it is preferably 50 g/m 2 or more and 1500 g/m 2 or less.
  • the basis weight of layer B is preferably 60 g/m 2 or more and 400 g/m 2 or less, and 70 g/m 2 from the viewpoint of preventing a decrease in workability due to an increase in the weight of the sound-absorbing material and from the viewpoint of reducing the amount of carbon dioxide emissions.
  • the basis weight of layer B can be controlled by adjusting the layer thickness, fiber diameter, etc., for example.
  • the thickness of layer B is preferably 0.1 mm or more and 100.0 mm or less, more preferably 0.3 mm or more and 60.0 mm or less, and 5.0 mm or more and 40.0 mm or less. It is more preferable.
  • layer B is made of short fibers of polyester resin (more preferably polyethylene terephthalate) and propylene resin, from the viewpoint of improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range. It may also be a nonwoven fabric containing short polymer fibers.
  • the average fiber diameter of the short fibers of the polyester resin is preferably 10 ⁇ m or more and 100 ⁇ m or less, more preferably 10 ⁇ m or more and 70 ⁇ m or less, and even more preferably 10 ⁇ m or more and 50 ⁇ m or less.
  • the ratio of the short fibers of the polyester resin to the short fibers of the propylene polymer is determined from the viewpoint of further improving sound absorption, and From the viewpoint of improving hydrophobicity and drainage properties, the ratio by mass is preferably 99:1 or more and 5:95 or less, more preferably 95:5 or more and 10:90 or less, and 80:20 or more and 20: More preferably, it is 80 or less.
  • layer B is made by mixing short fibers of propylene polymer with short fibers of polyester resin, forming a web through a spreading machine and a card machine, and then passing the obtained web into a cross layer machine.
  • a hot air treatment machine set at a predetermined gap distance, a nonwoven fabric is produced in which short fibers of polyester resin and short fibers of propylene polymer are fused together. I can do it.
  • Layer C has three or more layers of nonwoven fabric including a first spunbond nonwoven fabric, a meltblown nonwoven fabric, and a second spunbond nonwoven fabric, and has an air permeability of 48 cc/cm 2 /sec or less. Preferred aspects of the layer structure, material, and properties of layer C are the same as those of layer A.
  • the layer structure, material, and properties of layer C may be the same as or different from those of layer A, but the layer structure, material, and properties of layer C may be the same as or different from those of layer A. From the viewpoint of further reducing variations in sound absorption coefficient, it is preferable that at least one of the layer structure and the material is the same.
  • the fact that the material of layer C and the material of layer A are different means that the component compositions (layer structure, material, characteristics resulting from these, etc.) contained in each layer are different.
  • the materials of layer C and layer A are considered to be different.
  • the characteristics of layer C and layer A are considered to be different.
  • Layer D is a layer, foam, or back air layer with an air permeability of 20 cc/cm 2 /sec or more and 4500 cc/cm 2 /sec or less.
  • Layer D may be a single layer or a laminate of two or more layers.
  • Layer D is a layer with an air permeability of 20 cc/cm 2 /sec or more and 4500 cc/cm 2 /sec or less, from the viewpoint of further improving sound absorption over a wide frequency range and further reducing variations in sound absorption coefficient in the frequency range. It is preferably a foam or a layer or foam that is a back air layer and has an air permeability of 30 cc/cm 2 /sec to 4500 cc/cm 2 /sec.
  • a preferable embodiment of the layer and foam in which the air permeability in layer D is 20 cc/cm 2 /sec or more and 4500 cc/cm 2 /sec or less is that the air permeability in layer B is 20 cc/cm 2 /sec or more and 4500 cc/cm 2 /sec or less.
  • the preferred embodiments of the layer and foam are similar to those of the above.
  • the layer structure, material, and properties of layer D may be the same as or different from those of layer B, but the layer structure, material, and properties of layer D may be the same as or different from those of layer B. From the viewpoint of further reducing variations in sound absorption coefficient, it is preferable that at least one of the layer structure and the material is the same.
  • the material of layer D and the material of layer B are different, it means that the component compositions contained in each layer are different.
  • layer D and layer B are different in the type of resin, foam, etc. that constitute the layers (for example, in the case of nonwoven fabric, the type of resin that constitutes the fibers included in the nonwoven fabric), or when layer D is If they are layers, the materials of layer D and layer B are considered to be different.
  • layer D and layer B differ in air permeability, basis weight of fibers included in each layer, and average fiber diameter, the characteristics of layer D and layer B are considered to be different.
  • -Back air layer Layer D may be a back air layer.
  • the back air layer refers to a layer of voids from the surface of layer C opposite to the sound incident surface to the installation surface on which the sound absorbing material is installed.
  • the mounting surface may be a so-called reflective surface.
  • the sound absorbing material also includes a supporting material for maintaining a gap from the opposite side of the incident surface where the sound enters the layer C to the installation surface on which the sound absorbing material is attached.
  • the support material for example, known support materials such as metal or resin support rods, support frames, base materials, etc. can be used.
  • layer D is a back air layer
  • sound absorption properties are more likely to be improved over a wide frequency range, and variations in sound absorption coefficient are more likely to be reduced.
  • the layer D is a back air layer
  • the bonding strength between the sound incident surface and the supporting material is maintained by the materials and other properties of the other layers according to the present disclosure.
  • the tensile strength of at least one of layer A and layer C is preferably 50 N/50 mm or more, or 60 N/50 mm or more regardless of the MD direction or CD direction.
  • the range of the basis weight of layer C and the average fiber diameter of the spunbond nonwoven fabric are determined as described above. It is preferable to set it as the range of.
  • layer D is a back air layer
  • a spunbond nonwoven fabric or a spunbond nonwoven fabric containing a propylene polymer as the material for the other layers.
  • spunbond nonwoven fabric has sufficient surface strength, there is a low possibility that the front and back sides of the nonwoven fabric will be torn by sharp objects. The strength, installation strength, water resistance, etc. of the sound absorbing material itself are likely to be suppressed.
  • the basis weight of at least one of layer A and layer C and the average fiber diameter of the nonwoven fabric be within the above-mentioned ranges.
  • the thickness of the back air layer that is, the shortest distance of the air gap from the sound incident surface to the installation surface is not particularly limited, but is, for example, 2 mm or more, 5 mm or more, 8 mm or more, or 10 mm or more, and 50 mm or less, 30 mm or less, Or it can be 20 mm or less, and preferably 2 mm or more and 50 mm or less.
  • the thickness of the back air layer is the arithmetic average of the shortest distances measured at five arbitrary points from the opposite side of the entrance surface where sound enters in layer C to the installation surface on which the sound absorbing material is attached.
  • the method for manufacturing the sound absorbing material according to the present disclosure is not particularly limited, and any known manufacturing method can be applied.
  • the sound absorbing material according to the present disclosure may be manufactured by forming each layer separately and then laminating them, or may be manufactured by sequentially forming each layer while laminating them.
  • the resulting layers may be laminated.
  • layer B may be formed on layer A, and similarly layer C and layer D may be sequentially formed.
  • the bonding method between each layer of sound absorbing material can be selected as appropriate depending on the material of the layer, but for example, adhesives (e.g., hot melt adhesive, acrylic adhesive, urethane adhesive, polyamide adhesive, olefin adhesive etc.), thermal fusion (eg, heat treatment, hot embossing, ultrasonic fusion, etc.), mechanical entanglement (eg, needle punch, water jet, etc.), physical compression bonding, and combinations thereof.
  • adhesives e.g., hot melt adhesive, acrylic adhesive, urethane adhesive, polyamide adhesive, olefin adhesive etc.
  • thermal fusion eg, heat treatment, hot embossing, ultrasonic fusion, etc.
  • mechanical entanglement eg, needle punch, water jet, etc.
  • the sound absorbing material according to the present disclosure is manufactured by forming layer A, layer B, layer C, and layer D, respectively, and then joining the obtained layers by ultrasonic welding at the ends of each layer, such as radiant heat, etc. It may be manufactured by preheating each layer at a temperature and then physically compressing them.
  • the fusion temperature is not particularly limited as long as each layer can be fused, but from the viewpoint of suppressing peeling of the fused portion, it is 130°C or more and 160°C
  • the temperature is preferably below, and more preferably 140°C or more and 155°C or less.
  • the pressure is not particularly limited as long as it can pressure bond each layer, but from the viewpoint of suppressing peeling of the crimped part, it should be 0.1 MPa or more and 5 MPa or less. is preferred.
  • the speed at which the crimping part is formed is not particularly limited as long as each layer can be crimped, but from the viewpoint of suppressing peeling of the crimping part and improving work efficiency, it is 0.5 m/min or more and 30 m/min or less. It is preferable that there be.
  • the sound absorbing material according to the present disclosure may be subjected to secondary processing such as printing, coating, heat treatment, and shaping processing within a range that does not impair its effects.
  • the sound absorbing material according to the present disclosure exhibits excellent sound absorption properties in a high frequency range, that is, a wide frequency range of 1000 Hz and above, and has small variations in sound absorption coefficient, so it can be used for automobiles, electronic equipment, buildings, houses, etc. Applicable to various uses.
  • the sound absorbing material according to the present disclosure exhibits excellent sound absorption over a wide frequency range, reduces variations in sound absorption coefficient in the frequency range, and also has excellent scratch resistance (more specifically, wear resistance). Therefore, it is suitable as a sound-absorbing material for automobiles and railways, which requires blocking of external sounds over a wide frequency range and scratch resistance, and more preferably as a sound-absorbing material around tires (e.g., tire houses) and floors (e.g., undercovers). Can be used.
  • the sound absorbing material according to the present disclosure also has water pressure resistance on the surface on the sound incident surface side. Therefore, in order to suppress the deterioration of sound absorption properties due to water wetting, it is preferable to have water resistance in addition to sound absorption properties, such as tires, sound absorption materials around floors, sound absorption materials for ships, and sound absorption materials for civil engineering construction. It can be suitably used as
  • Fabric weight The layer to be measured was peeled off from the sound absorbing material. Subsequently, ten test pieces measuring 100 mm (fiber flow direction: MD) x 100 mm (direction perpendicular to the fiber flow direction (CD direction)) were taken from the nonwoven fabric. The test pieces were collected from 10 locations along the CD direction. Next, the mass [g] of each sampled test piece is measured using a top plate electronic balance (manufactured by Kensei Kogyo Co., Ltd.), and the arithmetic mean value of the mass of each test piece is determined. The average value determined above was converted into mass [g] per 1 m 2 and was defined as the basis weight [g/m 2 ] of each nonwoven fabric. Note that the total basis weight of the entire sound-absorbing material was taken as the sum of each layer.
  • MD fiber flow direction
  • CD direction direction
  • the layer to be measured was peeled off from the sound absorbing material, and 10 test pieces were taken. For each sample sample, the thickness was measured at five points at the center and four corners using a thickness gauge with a load of 7 g/cm 2 . The average value of the measured thicknesses at 50 points was calculated and used as the thickness (mm) of each layer. Note that the total thickness of the entire sound absorbing material was the sum of each layer.
  • Air Permeability The layer to be measured was peeled off from the sound absorbing material, and five test pieces were taken. For the test piece, the aeration amount (amount of air that passed through the layer) at a pressure difference of 125 Pa was measured using a Frazier type testing machine in accordance with JIS L1096 (2010) A method (Fragile type method), and the arithmetic mean was calculated. The value was taken as the air permeability. This measurement method was also applied to the measurement of the entire sound absorbing material.
  • Abrasion resistance (sandblasting resistance) A test piece of 200 mm (MD) x 25 mm (CD) was taken from layer A to be measured and attached to a mount with double-sided tape (NW-25 manufactured by Nichiban). Attach this mount to the sample holder of the Gakushin type friction fastness tester (RT-300S manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.), and use #180 sandpaper to remove loose particles of 1 mm or more under no load. The number of times the friction was applied until a pill was observed was measured. This measurement was repeated five times, and the arithmetic mean value was taken as the abrasion resistance.
  • RT-300S manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.
  • Tensile strength MD strength, CD strength (N/50mm)
  • a test piece of 200 mm (length direction) x 50 mm (width direction) was taken from layer A to be measured, and tested using a tensile tester (Shimadzu Autograph AGS-J) at a chuck distance of 100 mm and a head speed of 100 mm/min.
  • MD 5 points and CD: 5 points were measured, the average value was calculated, and the tensile strength (N/50 mm) was determined.
  • Average fiber diameter For spunbond nonwoven fabrics, take 10 test pieces of 10 mm x 10 mm and examine each test piece at 50x magnification using a microscope (manufactured by Nikon Corporation, product name: ECLIPSE E400). The diameters at 30 arbitrary locations were read in ⁇ m to the first decimal place, and the arithmetic mean value thereof was taken as the average fiber diameter of the fibers contained in the spunbond nonwoven fabric.
  • a microscope manufactured by Nikon Corporation, product name: ECLIPSE E400
  • the diameters at 30 arbitrary locations were read in ⁇ m to the first decimal place, and the average value was taken as the average fiber diameter.
  • the fiber diameters ( ⁇ m) of the 30 constituent fibers of the collected sample pieces were measured using a scanning electron microscope (manufactured by Hitachi, Ltd., model name: SU3500) at a magnification of 500x or 1000x. The arithmetic mean value was taken as the average fiber diameter of the fibers contained in the melt-blown nonwoven fabric.
  • Example 1 ⁇ Preparation of layer A> Using a propylene homopolymer with an MFR of 60 g/10 minutes, melt spinning was performed by a conventional spunbond method at 230°C using a spunbond nonwoven fabric forming machine having a spinneret with a diameter of 0.6 mm. The collected fibers were deposited on the collecting surface to obtain a first spunbond nonwoven fabric having an average fiber diameter of 13 ⁇ m and a basis weight of 10 g/m 2 . Next, a propylene homopolymer with an MFR of 400 g/10 minutes is melted at 280°C using an extruder, and the resulting melt is discharged from a spinneret, and heated air at 280°C is blown onto it.
  • Fibers with an average fiber diameter of 3 ⁇ m were deposited on the first spunbond nonwoven fabric by a conventional meltblown method to form a meltblown nonwoven fabric with a basis weight of 5 g/m 2 .
  • fibers were deposited on the meltblown nonwoven fabric in the same manner as the spunbond nonwoven fabric to form a second spunbond nonwoven fabric having an average fiber diameter of 13 ⁇ m and a basis weight of 10 g/m 2 .
  • a laminate in which the first spunbond nonwoven fabric, the meltblown nonwoven fabric, and the second spunbond nonwoven fabric were laminated in this order was heated to an embossed area ratio of 18% with the temperature set to 145°C for the embossing roll and 150°C for the mirror roll.
  • SMS structure A three-layer structure (hereinafter referred to as "SMS structure” or “PP-SMS”) in which a first spunbond nonwoven fabric and a second spunbond nonwoven fabric are integrated with a heat embossing roll and laminated on both the front and back sides of a meltblown nonwoven fabric. )
  • a nonwoven fabric was obtained.
  • the fabric weight of the obtained SMS structure nonwoven fabric was 25 g/m 2 .
  • melt spinning was performed by a conventional spunbond method at 230°C using a spunbond nonwoven fabric forming machine having a spinneret with a diameter of 1.3 mm.
  • the fibers obtained were deposited on the SMS structured nonwoven fabric to form a third spunbond nonwoven fabric with an average fiber diameter of 35 ⁇ m and a basis weight of 100 g/m 2 .
  • the laminate of the SMS structure nonwoven fabric and the spunbond nonwoven fabric was heated using a hot embossing roll (embossed pattern 0.9 mm square) with a temperature of 155°C for the embossing roll and 160°C for the mirror roll with an engraved area ratio of 18%. This was integrated to obtain a four-layer structure (hereinafter sometimes referred to as "SSMS structure” or "PP-SSMS”) nonwoven fabric in which the spunbond nonwoven fabric was laminated on the SMS structure nonwoven fabric as a skin material. .
  • SSMS structure four-layer structure
  • a sheet-like nonwoven fabric molded article (referred to as "PET type 1" in each table) containing short fibers of terephthal
  • melt spinning was performed by a conventional spunbond method at 230°C using a spunbond nonwoven fabric forming machine having a spinneret with a diameter of 0.6 mm.
  • the collected fibers were deposited on the collection surface to obtain a spunbond nonwoven fabric with an average fiber diameter of 21 ⁇ m and a basis weight of 40 g/m 2 .
  • a propylene homopolymer with an MFR of 400 g/10 minutes is melted at 280°C using an extruder, and the resulting melt is discharged from a spinneret, and heated air at 280°C is blown onto it.
  • Fibers with an average fiber diameter of 3 ⁇ m were deposited on the spunbond nonwoven fabric using a conventional melt blown method to form a meltblown nonwoven fabric with a basis weight of 25 g/m 2 .
  • fibers were deposited on the melt-blown nonwoven fabric in the same manner as the spunbond nonwoven fabric to form a second spunbond nonwoven fabric having an average fiber diameter of 21 ⁇ m and a basis weight of 20 g/m 2 .
  • the laminate of the spunbond nonwoven fabric, meltblown nonwoven fabric, and spunbond nonwoven fabric was integrated using a hot embossing roll with a stamping area ratio of 12% and the temperature of the embossing roll set at 145°C and the mirror roll 150°C, and the SMS structure nonwoven fabric was created. I got it.
  • the basis weight of the SMS structure nonwoven fabric was 85 g/m 2 .
  • each layer A to layer D was adjusted to 300 mm in the MD direction and 300 mm in the CD direction. Note that on layer A, 250 mm square marks are previously marked on the inner surface at 50 mm intervals from the ends of each of the four sides.
  • Layer A, layer B, layer C, and layer D are laminated in the order of 300 mm square so that there is no deviation, and with these four layers stacked, apply an ultrasonic sealer (Honda Electronics Co., Ltd. ultrasonic welding). The ends were fused using a SONAC-37).
  • the layer A was crimped along the lines of the 250 mm square with an ultrasonic sealer without any gaps. The width of the crimped portion was 2 mm or more. Cut out along the crimped portion to obtain a 250 mm square sound absorbing material.
  • Example 1 was carried out in the same manner as in Example 1, except that the layer structure of Layer A and Layer C of Example 1 was as shown in the table, and the physical properties such as basis weight, air permeability, and thickness of each layer were as shown in the table. Obtained sound absorbing material.
  • Example 8 Layers A to C were obtained in the same manner as in Example 1, except that the physical properties such as the layer structure, basis weight, air permeability, and thickness of each layer were as shown in the table. Subsequently, layer D, a sheet-like nonwoven fabric molded body, was not formed, but was used as a back protective layer, and layers A, B, and C were laminated in this order, and fused using an ultrasonic sealer in the same manner as in Example 1. A laminate was obtained. This laminate was sampled into a circular shape with a diameter of 29 mm.
  • Example 9 Layer A and layer C were obtained in the same manner as in Example 1, except that the physical properties such as the layer structure, basis weight, air permeability, and thickness of each layer were set to the specifications shown in the table. Subsequently, 10 parts by mass of short fibers of polyethylene terephthalate resin (average fiber diameter 20 ⁇ m, average fiber length 51 mm), 45 parts by mass of short fibers of polyethylene terephthalate resin (average fiber diameter 25 ⁇ m, average fiber length 51 mm), and polyethylene 45 parts by mass of short fibers of terephthalate resin (average fiber diameter 35 ⁇ m, average fiber length 51 mm) are mixed to form binder fibers.Acrylic emulsion binder (Boncourt AN-1170 manufactured by DIC Corporation, non-volatile content 50%) is used as a binder component.
  • Example 2 Concentration
  • Layer B was obtained in the same manner as in Example 1, except that the physical properties such as basis weight, air permeability, and thickness were as shown in the table.
  • Layer D which is a sheet-like nonwoven fabric molded body, is not formed, but is used as a back protection layer, and layers A, B, and C are laminated in this order, and they are fused and laminated with an ultrasonic sealer in the same manner as in Example 1. I got a body.
  • This laminate was sampled into a circular shape with a diameter of 29 mm. Then, at one end of the acoustic tube for measurement used in the [evaluation of sound absorption performance] described later, between the facing surface of the sound incident surface in layer C of the circular laminate and the reflection plate, as shown in Table 2.
  • a sound absorbing material was obtained by installing a spacer as a supporting material and arranging the laminate so that a rear air layer with a thickness of -1 was formed.
  • Example 10 Layer A and layer C were obtained in the same manner as in Example 1, except that the physical properties such as the layer structure, basis weight, air permeability, and thickness of each layer were set to the specifications shown in the table.
  • Layer B was changed to Eptsealer EX100 (thickness 10 mm, referred to as "foamed rubber” in the table) manufactured by Nitto Denko Corporation.
  • Layer A, layer B, and layer C were laminated in this order without forming a sheet-like nonwoven fabric molded body, which is layer D, and were fused using an ultrasonic sealer in the same manner as in Example 1 to obtain a laminate. This laminate was sampled into a circular shape with a diameter of 29 mm.
  • Example 11 The physical properties such as the layer structure, basis weight, air permeability, and thickness of each layer are as shown in the table, and the material of layer D is Hechimaron (product name) 350-1000 manufactured by Shinko Nylon Co., Ltd. A sound-absorbing material was obtained in the same manner as in Example 1, except that the resin molded body having the following was used (described as "three-dimensional mesh resin molded body" in the table).
  • Example 12 Layers A to C were obtained in the same manner as in Example 1, except that the physical properties such as the layer structure, basis weight, air permeability, and thickness of each layer were as shown in the table.
  • 80 parts by mass of short fibers of polyethylene terephthalate resin (average fiber diameter 25 ⁇ m, average fiber length 51 mm) and short fibers of polyethylene terephthalate resin as binder fiber (manufactured by Unitika Co., Ltd., trade name: Melty 4080, average fiber diameter 20 ⁇ m) , average fiber length 51 mm) and 20 parts by mass were mixed and formed into a web using a fiber opening machine and a card machine, and then laminated in multiple layers using a cross layer machine, followed by hot air treatment with a gap distance of about 20 mm.
  • a sheet-like nonwoven fabric molded article (referred to as "PET 3" in each table) with a thickness of about 20 mm was obtained by processing in a machine and containing short fibers of propylene polymer and short fibers of polyethylene terephthalate resin.
  • Layer D was obtained in the same manner as in Example 1 except for this.
  • a sound absorbing material was obtained in the same manner as in Example 1 using the obtained layers A to D.
  • Example 13 Layer A, layer C, and layer D were obtained in the same manner as in Example 1, except that the physical properties such as the layer structure, basis weight, air permeability, and thickness of each layer were set to the specifications shown in the table. Subsequently, a sound absorbing material was obtained in the same manner as in Example 1, using a sheet-like nonwoven fabric molded body (referred to as "PET system 4" in each table) as layer B, which was the same as PET system 2 except for the thickness.
  • PET system 4" sheet-like nonwoven fabric molded body
  • Example 14 to Example 16 A sound absorbing material was obtained in the same manner as in Example 1, except that the physical properties such as the layer structure, basis weight, air permeability, and thickness of each layer were set to the specifications shown in the table.
  • the electromagnetic shielding property (near field measuring device) of this layer A was measured using MS46122B (VNA vector network analyzer) manufactured by Anritsu.
  • the sample size was 100 mm in the MD direction and 50 mm in the CD direction, and the average value of 10 measurements was obtained.
  • the attenuation rate (Rtp value) at 6 GHz was 19.7.
  • the attenuation rate (Rtp value) of layer A at 6 GHz before coating was 0.0.
  • a sound absorbing material was obtained in the same manner as in Example 3, except that the layer structure and the physical properties such as the basis weight, air permeability, and thickness of the entire layer A were as shown in the table.
  • Example 2 A sound absorbing material was obtained in the same manner as in Example 1, except that the layer structure, basis weight, air permeability, thickness, and other physical properties of Layer A and Layer C were as shown in the table.
  • Example 4 A sound absorbing material was obtained in the same manner as in Example 1, except that the physical properties such as the layer structure, basis weight, air permeability, and thickness of each layer were as shown in the table. Layer A, layer B, and layer D were laminated in this order without forming layer C, and fused using an ultrasonic sealer in the same manner as in Example 1 to obtain a sound absorbing material.
  • Example 5 Layer A was obtained in the same manner as in Example 1, except that the basis weight configuration, average fiber diameter of the spunbond nonwoven fabric, air permeability of the entire layer A, and thickness were changed as shown in the table. Same as Example 1, except that layer B was changed to Thinsulate (registered trademark) TC3403 (mixed fiber of polyester fiber and polypropylene fiber, referred to as "PP-MB/PET" in the table) manufactured by 3M Company. Obtained using the method. Layer A and layer B were laminated in this order without forming layer C and layer D, and they were fused using an ultrasonic sealer in the same manner as in Example 1 to obtain a sound absorbing material.
  • Thinsulate registered trademark
  • TC3403 mixed fiber of polyester fiber and polypropylene fiber
  • Layer B and layer D are made of foam-molded urethane sheets (manufactured by INOAC, product name: ECS10, density: 22 kg/m 3 , referred to as "foamed urethane” in the table), and the layer structure and basis weight of each layer are A sound absorbing material was obtained in the same manner as in Comparative Example 1, except that the physical properties such as air permeability and thickness were as shown in the table.
  • Layer A and layer C had the same specifications as in Example 9.
  • 60 parts by mass of short fibers of propylene polymer manufactured by Ube Eximo Co., Ltd., product name: UC fiber, average fiber diameter 21 ⁇ m, average fiber length 51 mm
  • short fibers of polyethylene terephthalate resin as binder fiber (Unitika Co., Ltd.) (trade name: Melty 4080, average fiber diameter 14 ⁇ m, average fiber length 51 mm) was mixed with 40 parts by mass, and a web was formed using a spreading machine and a card machine, and then multi-layered was laminated using a cross layer machine to form a web of about 50 mm.
  • a sheet-like nonwoven fabric molded article (in the table, it is treated with a hot air treatment machine set at a gap distance of -PET-based layer B was obtained.
  • layer B was cut into a size of 250 mm (length) x 250 mm (width) x 50 mm (thickness).
  • layer A and layer C are placed on both the front and back surfaces of cut layer B, with spunbond nonwoven fabrics 4a and 4c facing the outermost surface, and the peripheral edge of the skin material around layer B is
  • a continuous sheet of 0.3 mm width was fused using an ultrasonic sealing machine (manufactured by Seidensha Electronics Co., Ltd., product name: J11430SA) under the conditions of output 2.0 V, pressure 0.3 MPa, and speed 5 m/min.
  • a seal portion was formed to obtain a sound absorbing material in which the layer B was included in the layers A and C.
  • the excess portion of the outer periphery of the seal portion was cut and deleted.
  • Layer A, Layer B, and Layer C were laminated in this order without forming Layer D, and fused using an ultrasonic sealer in the same manner as in Example 1 to obtain a sound absorbing material.
  • the values of each physical property measured by the above-mentioned measurement method are summarized in each table.
  • SB is an abbreviation for spunbond nonwoven fabric
  • MB is an abbreviation for meltblown nonwoven fabric.
  • the air permeability unit ccs is an abbreviation of cc/cm 2 /sec.
  • SB average fiber diameter for layer A and layer C
  • the average fiber diameter of the fibers contained in each of the plurality of spunbond nonwoven fabrics laminated in the layer thickness direction from the incident surface side where sound is incident is different.
  • the average fiber diameters of the fibers contained in the plurality of spunbond nonwoven fabrics are listed in this order from the left.
  • the item [fabric weight structure] in layer A and layer C indicates the value of the fabric weight of each laminated nonwoven fabric.
  • the layer structure of layer A is, in the layer thickness direction from the sound incident surface side, a third spunbond nonwoven fabric, a first spunbond nonwoven fabric, a meltblown nonwoven fabric, and a second spunbond nonwoven fabric.
  • the bonded nonwoven fabrics are laminated in this order (PP-SSMS structure), and the basis weight values of these four types of nonwoven fabrics are 100 (g/m 2 ), 10 (g/m 2 ), and 5 (g/m 2 ) in that order. 2 ) and 10 (g/m 2 ).
  • Example 17 in addition to the value of the basis weight of each laminated nonwoven fabric, the basis weight (2 g/m 2 ) of the conductive material is also written at the left end.
  • the item [fabric weight] for layer A and layer C is a value measured for the entire layer of layer A and layer C, respectively.
  • the normal incidence sound absorption coefficient was measured.
  • a normal incidence sound absorption coefficient measuring device manufactured by Brüel & Kj ⁇ r, TYPE 4206 was measured in accordance with ASTM E 1050 using an acoustic tube provided with the sound absorbing material.
  • the normal incidence sound absorption coefficient was measured when a plane sound wave with a frequency of 1000 Hz to 6300 Hz was perpendicularly incident on the test piece. From the obtained sound absorption coefficient curve for 1000Hz to 6300Hz, the normal incidence sound absorption coefficients (hereinafter simply referred to as "sound absorption ) was calculated.
  • Average sound absorption coefficient (1000 Hz sound absorption coefficient + 1250 Hz sound absorption coefficient + 1600 Hz sound absorption coefficient + 2000 Hz sound absorption coefficient + 2500 Hz sound absorption coefficient + 3150 Hz sound absorption coefficient + 4000 Hz sound absorption coefficient + 5000 Hz sound absorption coefficient + 630 Sound absorption coefficient at 0Hz))/9
  • Standard deviation of sound absorption coefficient (((1000Hz sound absorption coefficient - average sound absorption coefficient) 2 + (1250Hz sound absorption coefficient - average sound absorption coefficient) 2 + (1600Hz sound absorption coefficient - average sound absorption coefficient) 2 + (2000Hz sound absorption coefficient - average sound absorption coefficient) Sound absorption coefficient - Average sound absorption coefficient) 2 + (Sound absorption coefficient of 2500Hz - Average sound absorption coefficient) 2 + (Sound absorption coefficient of 3150Hz - Average sound absorption coefficient) 2 + (Sound absorption coefficient of 4000Hz - Average sound absorption coefficient) 2 + (Sound absorption coefficient of 5000Hz rate - average sound absorption coefficient) 2 + (6300Hz sound absorption coefficient - average sound absorption coefficient) 2 )/9) 0.5
  • the sound absorbing materials of the examples according to the present disclosure exhibit excellent sound absorbing properties over a wide frequency range from 1000 Hz onwards, which is a high frequency region, compared to the sound absorbing materials of the comparative examples according to the present disclosure, In addition, variations in sound absorption coefficient in the frequency range were reduced. Further, it was found that the sound absorbing material of the example according to the present disclosure also has excellent wear resistance compared to the sound absorbing material of the comparative example according to the present disclosure.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
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  • Laminated Bodies (AREA)

Abstract

Le matériau absorbant acoustique de l'invention comprend au moins trois couches de non-tissé comprenant un premier non-tissé filé-lié, un non-tissé obtenu par fusion-soufflage et un second non-tissé filé-lié. Le matériau absorbant acoustique comprend, dans l'ordre suivant le long du sens de l'épaisseur de la couche depuis le côté d'une surface d'entrée par laquelle le son pénètre : une couche A dont la perméabilité à l'air ne dépasse pas 48 cc/cm2/sec ; une couche B qui est une couche ou un corps en mousse dont la perméabilité à l'air est comprise entre 20 cc/cm2/sec et 4500 cc/cm2/sec ; une couche C comprenant les trois couches ou plus de non-tissé, comportant le premier non-tissé filé-lié, le non-tissé obtenu par fusion-soufflage et le second non-tissé filé-lié, dont la perméabilité à l'air ne dépasse pas 48 cc/cm2/sec ; et une couche D qui est une couche, un corps en mousse ou une couche d'air arrière dont la perméabilité à l'air est comprise entre 20 cc/cm2/sec et 4500 cc/cm2/sec.
PCT/JP2023/012311 2022-03-31 2023-03-27 Matériau absorbant acoustique WO2023190398A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2021192983A (ja) * 2017-03-31 2021-12-23 三井化学株式会社 積層体及び吸音材
WO2022009835A1 (fr) * 2020-07-07 2022-01-13 三井化学株式会社 Tissu non tissé composite et son procédé de fabrication

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2021192983A (ja) * 2017-03-31 2021-12-23 三井化学株式会社 積層体及び吸音材
WO2022009835A1 (fr) * 2020-07-07 2022-01-13 三井化学株式会社 Tissu non tissé composite et son procédé de fabrication

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