WO2018182001A1

WO2018182001A1 - Laminate body and sound-absorbing material

Info

Publication number: WO2018182001A1
Application number: PCT/JP2018/013934
Authority: WO
Inventors: 康三飯場
Original assignee: 三井化学株式会社
Priority date: 2017-03-31
Filing date: 2018-03-30
Publication date: 2018-10-04
Also published as: JPWO2018182001A1; JP7206564B2; JP2021192983A

Abstract

A laminate body in which are laminated, in the stated order: a first layer having air permeability of no more than 1 cc/cm2/sec, and less than 30 cc/cm2/sec; a second layer having air permeability of 30 cc/cm2/sec to 1000 cc/cm2/sec; a third layer having air permeability of no more than 1 cc/cm2/sec and less than 30 cc/cm2/sec; and a fourth layer having air permeability of 30 cc/cm2/sec to 1000 cc/cm2/sec.

Description

Laminate and sound absorbing material

The present disclosure relates to a laminate and a sound absorbing material.

Polyurethane foam and polyethylene foam containing an air layer for the purpose of blocking noise from the outside and not leaking the sound from the outside in transportation environments such as living environments such as houses and offices, aircraft, vehicles, automobiles, etc. Sound absorbing materials made of fibrous materials such as foams, felts, nonwoven fabrics and the like are widely used.

In particular, transportation means such as automobiles are required to have a light-absorbing material that is lighter in weight and excellent in sound-absorbing performance. Therefore, as a method for improving sound-absorbing performance, two or three layers of different materials are bonded together. Have been proposed (for example, Patent Document 1 to Patent Document 5).

Patent Document 1: Japanese Patent Laid-Open No. 2002-69823 Patent Document 2: Japanese Patent Laid-Open No. 2002-161565 Patent Document 3: Japanese Patent Laid-Open No. 2003-49351 Patent Document 4: Japanese Patent Laid-Open No. 2014-2322281 2013-139188 gazette

However, as in the laminates proposed in Patent Documents 1 to 4, a laminate in which layers of different materials are laminated to form two layers exhibits an excellent sound absorption coefficient in a specific frequency region, but the frequency region There is a problem in that the sound absorption rate is reduced.
Moreover, although the laminated body proposed in Patent Document 5 shows sound absorption in a wide frequency range, it is still not sufficient.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a laminate that exhibits excellent sound absorption over a wide frequency range, and a sound absorbing material including the laminate.

Specific means for solving the above-described problems are as follows.
<1> a first layer of the air permeability is less than 1 cc ^/ cm 2 / sec or more 30cc ^/ cm 2 ^/ sec, and the second layer air permeability following 30 cc ^/ cm 2 / sec or more 1000 cc ^/ cm 2 / sec A third layer having an air permeability of 1 cc / cm ² / sec or more and less than 30 cc / cm ² / sec, and a fourth layer having an air permeability of 30 cc / cm ² / sec or more and 1000 cc / cm ² / sec or less. Laminated body laminated in this order.
<2> The laminate according to <1>, wherein at least one of the first layer and the third layer is a nonwoven fabric, a porous film, a woven fabric, or a foam.
<3> The laminate according to <1> or <2>, wherein at least one of the second layer and the fourth layer is a nonwoven fabric, a woven fabric, or a foam.
<4> The laminate according to any one of <1> to <3>, wherein the thickness of the first layer and the thickness of the third layer are 0.1 mm or more and 2 mm or less, respectively.
<5> The laminate according to any one of <1> to <4>, wherein the thickness of the second layer and the thickness of the fourth layer are 10 mm or more and 50 mm or less, respectively.

<6> A sound absorbing material comprising the laminate according to any one of <1> to <5>.

The present disclosure can provide a laminate exhibiting excellent sound absorption over a wide frequency range, and a sound absorbing material including the laminate.

FIG. 1 is a schematic partial cross-sectional view showing an example of the layer configuration of the laminate according to the present embodiment. FIG. 2 is a diagram illustrating the frequency characteristics of the sound absorption coefficient in the sound absorbing materials of Example 1, Comparative Example 1, and Comparative Example 5. FIG. 3 is a schematic partial sectional view showing an example of a layer structure of a conventional laminate.

In this specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Laminate]
Hereinafter, an embodiment of a laminate according to the present disclosure will be described.
The laminate according to the present embodiment has a first layer (hereinafter, also referred to as “low-breathing A layer”) having an air permeability of 1 cc / cm ² / sec or more and less than 30 cc / cm ² / sec, and an air permeability of 30 cc / cm. ^{A second} layer (hereinafter also referred to as “highly-permeable B layer”) of ² / sec or more and 1000 cc / cm ² / sec or less, and a third layer having an air permeability of 1 cc / cm ² / sec or more and less than 30 cc / cm ² / sec. A layer (hereinafter also referred to as a “low air permeability C layer”) and a fourth layer (hereinafter also referred to as a “high air permeability D layer”) having an air permeability of 30 cc / cm ² / sec to 1000 cc / cm ² / sec. It is the laminated body laminated | stacked in this order.
A layer having an air permeability of 1 cc / cm ² / sec or more and less than 30 cc / cm ² / sec is also collectively referred to as a “low air permeability layer”, and the air permeability is 30 cc / cm ² / sec or more and 1000 cc / cm ² / sec or less. These layers are also collectively referred to as “highly breathable layers”.

Here, the air permeability (cc / cm ² / sec) was measured at a pressure difference of 125 Pa in accordance with JIS L1096 (2010) A method (fragile type method) using a Frazier type tester at five locations of the sample. This is an average value obtained by measuring the air flow rate (the amount of air passing through the layer).
In addition, when measuring the air permeability of each layer in a laminated body, it peels from the laminated body and measures it. However, if it is difficult to peel the entire layer to be measured from the laminate, the thickness of the layer to be measured is measured, and the air flow rate of a sample cut out in the thickness direction is measured to determine the layer thickness. The air permeability of the entire layer to be measured may be obtained by converting the value into consideration.

FIG. 1 shows an example of the layer structure of the laminate according to this embodiment.
In the laminate 10 shown in FIG. 1, a low air permeability A layer 12, a high air permeability B layer 14, a low air permeability C layer 16, and a high air permeability D layer 18 are laminated in this order.
Since the laminate 10 has the above-described configuration, it exhibits excellent sound absorption over a wide frequency range. The reason is presumed as follows.

As a conventional sound-absorbing material, for example, as shown in FIG. 3, there is a laminated body 110 in which a low air-permeable layer 112 and a high air-permeable layer 114 are laminated to form two layers. In the laminate 110, the two-layer configuration described above allows the low ventilation layer 112 to function as a sound absorption layer and the high ventilation layer 114 to function as a back air layer. Higher sound absorption performance can be obtained. Specifically, when the surface 115 of the high air permeability layer 114 opposite to the low air permeability layer 112 is a fixed end of the standing wave, a sound near the frequency where the antinode of the standing wave becomes the position of the low air permeability layer 112 (for example, the wavelength is high). A high sound absorption coefficient is obtained for a sound that is four times the thickness of the ventilation layer 114.
However, in the laminate 110, the sound other than the specific frequency, particularly, the sound near the frequency where the node of the standing wave is the position of the low ventilation layer 112 (for example, the wavelength is twice the thickness of the high ventilation layer 114). For a certain sound, it is difficult to obtain a high sound absorption coefficient.

On the other hand, the laminated body 10 is laminated | stacked in order of the low ventilation A layer 12, the high ventilation B layer 14, the low ventilation C layer 16, and the high ventilation D layer 18. In FIG. That is, the laminated body 10 has air permeability at a position corresponding to half of the thickness of the high ventilation layer 114 in the laminated body 110 in addition to the low ventilation layer A 12 at the same position as the low ventilation layer 112 in the laminated body 110. A low air permeability C layer 16 having a low thickness is provided.
As in the case of the laminate 110, when the low air permeability A layer 12 functions as a sound absorbing layer, the surface 19 on the opposite side of the low air permeability C layer 16 in the high air permeability D layer 18 is a stationary wave stationary end. A high sound absorption coefficient can be obtained with respect to the sound in the vicinity of the frequency where the antinode is located at the position of the low ventilation A layer 12. In addition, the low-air-permeable C layer 16 also functions as a sound-absorbing layer, so that the sound near the frequency where the node of the standing wave becomes the position of the low-air-permeable A layer 12 and the anti-node of the standing wave becomes the position of the low-air-permeable C layer 16 ( In other words, a high sound absorption coefficient can be obtained even for a sound that is difficult to obtain a high sound absorption coefficient in the laminate 110.
Thus, the laminate 10 exhibits excellent sound absorption over a wide frequency range.

When the laminate 110 is used as a sound absorbing material, the thickness of the entire laminate may be limited depending on the environment in which the sound absorbing material is installed, and the frequency at which a high sound absorption coefficient is obtained depends on the thickness of the high ventilation layer 114. In some cases, it is difficult to obtain a high sound absorption coefficient for a target frequency. However, if the laminate 10 is used as a sound absorbing material, it exhibits excellent sound absorption over a wide frequency range, so that it is easy to obtain a high sound absorption coefficient for the target frequency range without changing the thickness of the entire laminate.

In addition, the laminated body 10 should just laminate | stack the low ventilation A layer 12, the high ventilation B layer 14, the low ventilation C layer 16, and the high ventilation D layer 18 in this order. You may further have a layer (for example, a reinforcement layer, an adhesive layer, etc.).
The other layers are provided between the layers (ie, between the low air permeability A layer 12 and the high air permeability B layer 14, between the high air permeability B layer 14 and the low air permeability C layer 16, and between the low air permeability C layer 16 and the high air permeability D layer 18). Alternatively, it may be provided on the outer surface (that is, the surface on the side opposite to the high air permeability B layer 14 in the low air permeability A layer 12, the surface 19).
Further, in order to eliminate the dependency of the sound absorption rate on the incident direction, a layer having a low air permeability may be further provided on the surface 19 of the laminate 10.
Furthermore, the laminate 10 may further include a low air permeability layer and a high air permeability layer in addition to the low air permeability A layer 12, the high air permeability B layer 14, the low air permeability C layer 16, and the high air permeability D layer 18. Specifically, for example, a laminated body having a six-layer structure, a laminated body having an eight-layer structure, or the like in which a combination of a low air-permeable layer and a high air-permeable layer is further added to the surface 19 side of the high-air-permeable D layer 18 can be given. Among these, in particular, a laminate having a six-layer structure in which a low air permeability A layer, a high air permeability B layer, a low air permeability C layer, a high air permeability D layer, a low air permeability E layer, and a high air permeability F layer are laminated in this order (not shown). ) Is preferred.
As the low air permeability E layer, a layer having an air permeability of 1 cc / cm ² / sec or more and less than 30 cc / cm ² / sec is preferable like the low air permeability A layer. The basis weight and thickness of the low air permeability E layer are also the same as those of the low air permeability A layer. In addition, the high air permeability F layer is the same as the high air permeability B layer. A layer having an air permeability of 30 cc / cm ² / sec to 1000 cc / cm ² / sec is preferable. The basis weight and thickness of the high ventilation F layer are also the same as those of the high ventilation B layer.
That is, among the laminate further having a low air permeability layer and a high air permeability layer, a first layer that is a low air permeability layer, a second layer that is a high air permeability layer, and a third layer that is a low air permeability layer; A laminate in which a fourth layer that is a high air permeability layer, a fifth layer that is a low air permeability layer, and a sixth layer that is a high air permeability layer is laminated in this order is preferable.

In the laminated body 10, the low air permeability A layer 12 and the low air permeability C layer 16 are layers having the same material, the same characteristics, and the same thickness. Not limited. The materials, characteristics, and thicknesses of the low air permeability layers (that is, the low air permeability A layer 12 and the low air permeability C layer 16) may be the same or different.
Moreover, in the laminated body 10, although the high ventilation B layer 14 and the high ventilation D layer 18 are the layers which have the same material, the same characteristic, and the same thickness, if the air permeability of each layer is the said range, it will be to this Not limited. The materials, characteristics, and thicknesses of the high air permeability layers (that is, the high air permeability B layer 14 and the high air permeability D layer 18) may be the same or different.
If the air permeability of each layer is within the above range, both the low air permeability layer and the high air permeability layer may be made of the same material (for example, non-woven fabric).
As described above, the laminate of the present disclosure exhibits excellent sound absorption over a wide frequency range. And the sound absorption material containing the laminated body of this indication can be used suitably for a motor vehicle use. In particular, since the electric vehicle requires a wide range of sound absorption characteristics from low road noise to high motor sound, the laminate of the present disclosure having excellent sound absorption over a wide frequency range is particularly useful.

<Air permeability>
Air permeability of the low air A layer 12 and the low air C layer 16 are each less than 1cc ^/ cm 2 ^/ sec or more 30cc ^/ cm 2 ^/ sec, preferably not more than 3cc ^/ cm 2 ^/ sec or more 20cc ^/ cm 2 ^/ sec 5 cc / cm ² / sec or more and 10 cc / cm ² / sec or less is more preferable.
When the air permeability of the low air permeability A layer 12 and the low air permeability C layer 16 is within the above range, the air permeability of the entire laminate can be suppressed lower than when the air permeability is higher than the above range, and compared with the case where the air permeability is lower than the above range. The function as a sound absorbing layer is easily exhibited.

The air permeability of the high air permeability B layer 14 and the high air permeability D layer 18 is 30 cc / cm ² / sec or more and 1000 cc / cm ² / sec or less, respectively, preferably 40 cc / cm ² / sec or more and 700 cc / cm ² / sec or less. 50 cc / cm ² / sec or more and 500 cc / cm ² / sec or less is more preferable.
Since the air permeability of the high air permeability B layer 14 and the high air permeability D layer 18 is in the above range, less sound waves are reflected in the middle of the sound absorbing material than in the case where the air permeability is lower than the above range, and the back air compared with the case where the air permeability is higher than the above range. The function as a layer is easily exhibited.

The air permeability of the high air permeability B layer 14 is preferably not less than 2 times and not more than 100 times the air permeability of the low air permeability A layer 12, more preferably not less than 5 times and not more than 50 times, and further preferably not less than 10 times and not more than 20 times.
The air permeability of the low air permeability C layer 16 is preferably 0.5 times or more and 2 times or less, more preferably 0.7 times or more and 1.5 times or less, more preferably 0.9 times or more and 1 times that of the low air permeability A layer 12. More preferably, it is 1 times or less.
The air permeability of the high air permeability D layer 18 is preferably 2 times or more and 100 times or less, more preferably 5 times or more and 50 times or less, and further preferably 10 times or more and 20 times or less of the air permeability of the low air permeability C layer 16.
When the ratio of the air permeability between the respective layers is in the above range, the roles of the low air permeability layer and the high air permeability layer are exhibited, and the sound absorption coefficient of the laminate is increased.

Air permeability of the laminate as a whole, from the viewpoint of sound absorption rate improves, for example, 1cc ^/ cm 2 ^/ sec or more 25cc ^/ cm 2 ^/ sec or less and the like, is preferably from 2cc ^/ cm 2 ^/ sec or more 15cc ^/ cm 2 ^/ sec It is more preferably 3 cc / cm ² / sec or more and 10 cc / cm ² / sec or less.

<Thickness>
The thickness of the low air permeability A layer 12 and the low air permeability C layer 16 is preferably 0.1 mm or more and 2 mm or less, more preferably 0.1 mm or more and 1 mm or less, respectively, from the viewpoint of adjusting the air permeability of the entire laminate to the above range. More preferably, it is 0.1 mm or more and 0.5 mm or less.
The thicknesses of the high ventilation B layer 14 and the high ventilation D layer 18 are not limited and set according to the frequency of the sound for which the sound absorption rate is desired to be increased, but for example, 10 mm or more and 50 mm or less, preferably 10 mm or more and 40 mm or less, More preferably, 10 mm or more and 30 mm or less are mentioned.
The ratio of the thickness of the high air permeability B layer 14 to the thickness of the high air permeability D layer 18 is not particularly limited, and the low air permeability C layer 16 may be provided at a position where the sound absorption coefficient in the target frequency region is improved. From the viewpoint of facilitating the sound absorption of the low-breathing A layer at a frequency that is difficult for the low-breathing A layer to absorb sound, the thickness of the high-breathing D layer 18 is 0.7 times or more that of the high-breathing B layer 14. It is preferably 3 times or less, and more preferably 0.9 times or more and 1.1 times or less.
The thickness of the entire laminate is set according to the frequency of the sound for which the sound absorption rate is desired to be increased and the environment in which the laminate is installed, but is not limited to, for example, 20 mm to 100 mm, and 25 mm to 80 mm. The following is preferable, and 30 mm or more and 60 mm or less are more preferable.

<Material>
The material of the low air permeability layer and the high air permeability layer is not particularly limited as long as the air permeability in each layer is within the above range. For example, sheets such as nonwoven fabric, foam, porous film, paper, woven fabric, knitted fabric, felt, inorganic fiber, etc. The thing of the shape is mentioned.

As a nonwoven fabric, the nonwoven fabric comprised including the organic fiber (for example, resin fiber etc.) or its mixture is mentioned, A long fiber nonwoven fabric or a short fiber nonwoven fabric may be sufficient. Examples of the nonwoven fabric include melt blown nonwoven fabric, spunbond nonwoven fabric, needle punched nonwoven fabric, thermal bond nonwoven fabric, chemical bond nonwoven fabric, stitch bond nonwoven fabric, and spunlace nonwoven fabric.
The air permeability of the nonwoven fabric can be controlled by adjusting the thickness, basis weight, fiber diameter, and the like, and can also be controlled by adjusting the porosity and the like by post-processing such as calendaring.

Examples of the foam include a resin material containing bubbles. Examples of the foam include polyurethane foam, polyolefin foam (for example, polyethylene polypropylene foam), polystyrene foam, acrylic copolymer foam, rubber foam, and the like.
The air permeability of the foam can be controlled by adjusting the thickness, density, closed cell ratio, and the like, for example.

Examples of the porous film include a microporous film and a mesoporous film. Examples of the porous film include a resin porous film such as a film made porous by stretching a resin containing a filler, an inorganic porous film such as a cement porous body film, and a film having holes formed by processing such as a needle punch. It is done.
The air permeability of the porous film can be controlled by adjusting the thickness, density, pore diameter and the like, for example.
Examples of the inorganic fiber include glass fiber and carbon fiber.

-Material of low ventilation layer-
Among these, the material of the low air permeability layer is preferably a nonwoven fabric, a porous film, a woven fabric, or a foam. preferable.

When a melt blown nonwoven fabric is used as the low air permeability layer, the average fiber diameter of the thermoplastic resin fibers constituting the melt blown nonwoven fabric is, for example, in the range of 0.1 μm to 10 μm, preferably 1 μm to 10 μm.

Hereinafter, a melt blown nonwoven fabric will be described as an example of a material used for the low air permeability layer.
The melt-blown nonwoven fabric is obtained, for example, by discharging a molten thermoplastic resin composition (that is, a composition containing a thermoplastic resin) from a nozzle and blowing a gas into fibers to collect the nonwoven fabric.

The thermoplastic resin is not particularly limited as long as it is a thermoplastic resin capable of forming a nonwoven fabric, and various known ones can be used.
Examples of the thermoplastic resin include a polyolefin-based polymer which is a homopolymer or copolymer of an α-olefin such as ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene. Coalesce is mentioned.

Examples of olefin polymers include ethylene homopolymers such as high-pressure low-density polyethylene, linear low-density polyethylene (so-called LLDPE), and high-density polyethylene; ethylene-propylene random copolymer, ethylene / 1-butene random Ethylene polymers such as ethylene / α-olefin copolymers such as copolymers; propylene homopolymers (so-called polypropylene); propylene / ethylene random copolymers, propylene / ethylene / 1-butene random copolymers ( So-called random polypropylene), propylene-based polymers such as propylene block copolymer, propylene / 1-butene random copolymer; 1-butene homopolymer, 1-butene / ethylene copolymer, 1-butene / propylene copolymer 1-butene polymers such as polymers; poly-4-methyl-1-pen Emissions homopolymer, 4-methyl-1-pentene-propylene copolymer, 4-methyl-1-pentene polymer and 4-methyl-1-pentene-alpha-olefin copolymer; and the like.

As the thermoplastic resin, in addition to the above polyolefin polymer, polyester (eg, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamide (eg, nylon-6, nylon-66, polymetaxylene adipamide) Etc.), polyvinyl chloride, polyimide, ethylene / vinyl acetate copolymer, polyacrylonitrile, polycarbonate, polystyrene, ionomer or a mixture thereof.

Among these thermoplastic resins, polyolefin polymers are preferred from the viewpoints of spinning stability during molding, and processability of nonwoven fabric, breathability, flexibility, lightness, and heat resistance. Among these, a propylene polymer is more preferable from the viewpoints of heat resistance and light weight. The thermoplastic resin is more preferably a propylene homopolymer or a propylene / α-olefin copolymer among propylene polymers.

Examples of the propylene polymer suitable as the thermoplastic resin include a propylene homopolymer having a melting point (Tm) in the range of 125 ° C. or higher (preferably 130 to 165 ° C.), or one or two or more types of propylene. Α-olefins having 2 or more carbon atoms (preferably 2 to 8 carbon atoms), such as ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene, etc., but propylene Are preferred.

As long as the propylene-based polymer can be melt-spun, the melt flow rate (MFR: ASTM D-1238, 230 ° C., load 2160 g) is not particularly limited, but for example, 10 g / 10 min to 4000 g / 10 min, preferably 50 g / 10 min to 3000 g / 10 min, more preferably 100 g / 10 min to 2000 g / 10 min.

The thermoplastic resin composition for forming the thermoplastic resin fiber includes an antioxidant, a weather stabilizer, a light stabilizer, an anti-blocking agent, a lubricant, a pigment, a softener, and a hydrophilic agent as long as the purpose of the present disclosure is not impaired. In addition, various known additives such as an auxiliary, a water repellent, a filler, and an antibacterial agent may be contained.

The melt blown nonwoven fabric may be composed only of fibers formed by the melt blown method, and may contain other fibers. The other fibers may be short fibers or long fibers, or may be crimped fibers or uncrimped fibers. These other fibers can be added for any purpose such as imparting mechanical properties such as imparting strength, imparting chemical properties, and increasing the amount.
Examples of the other fibers include polyester short fibers such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.
In addition, as content of another fiber, 20 mass% or less with respect to the whole melt blown nonwoven fabric, Preferably it is 10 mass% or less, More preferably, 5 mass% or less is mentioned.

-Material of high ventilation layer-
Among these, the material of the high air permeability layer is preferably a nonwoven fabric or a foam, and among them, a melt blown nonwoven fabric, a spunbond nonwoven fabric, a needle punched nonwoven fabric, a glass fiber nonwoven fabric, a polyurethane foam, or a polyolefin foam is more preferable. Further, a melt blown nonwoven fabric is more preferable, and a polyurethane foam is particularly preferable.

When a melt blown nonwoven fabric is used as the high air permeability layer, the average fiber diameter of the thermoplastic resin fibers constituting the melt blown nonwoven fabric is, for example, in the range of 1 μm to 60 μm, preferably 3 μm to 20 μm.
In addition, about the component etc. which are contained in the melt blown nonwoven fabric used for a high ventilation layer, it is the same as that of the melt blown nonwoven fabric used for the above-mentioned low ventilation layer.

When a foam is used as the high ventilation layer, the density measured in accordance with ASTM D792 Method A (submersion method) in the foam is, for example, 9.0 kg / m ³ to 200 kg / m ³ , preferably 10 kg. / M ³ to 200 kg / m ³ , more preferably 20 kg / m ³ to 200 kg / m ³ .
Further, the closed cell ratio measured in accordance with ASTM D2856 C method in the foam used for the high air-permeable layer is, for example, 0% or more and less than 60%, preferably 0 to 55%, more preferably 0 to 50%. %. That is, it is preferable that the foam used for the high ventilation layer has an open cell structure from the viewpoint of increasing the air permeability of the high ventilation layer and the sound absorption coefficient of the laminate.
Moreover, as an average diameter (average cell diameter) of the cell in the foam used for a high air layer, 10 micrometers or more and 2000 micrometers or less, for example, Preferably they are 300 micrometers or more and 2000 micrometers or less, More preferably, they are 600 micrometers or more and 2000 micrometers or less.

Hereinafter, the polyurethane foam used for the highly breathable layer will be described.
The polyurethane foam can be obtained, for example, by reacting a composition containing polyisocyanate, a polyol, a foaming agent, and other components as necessary.
Examples of the polyisocyanate include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and derivatives thereof. These may be used alone or in combination of two or more. .

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate (TMDI), pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), 1,2-, 2,3- or 1,3-butylene diisocyanate. 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate and the like.

Examples of the alicyclic polyisocyanate include 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), dicyclohexylmethane diisocyanate (for example, 4,4′-, 2,4′-, Or 2,2′-dicyclohexylmethane diisocyanate or mixtures thereof, H12MDI), bis (isocyanatomethyl) norbornane (eg, 2,5- or 2,6-bis (isocyanatomethyl) norbornane or mixtures thereof, NBDI), 1 , 3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate Over doors and the like.

Examples of the aromatic polyisocyanate include xylylene diisocyanate (for example, 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, XDI), tetramethylxylylene diisocyanate (for example, 1,3- or 1,4). -Tetramethylxylylene diisocyanate or mixtures thereof, TMXDI), ω, ω'-diisocyanato-1,4-diethylbenzene, diphenylmethane diisocyanate (eg 4,4'-, 2,4'- or 2,2'-diphenylmethane Diisocyanate or mixtures thereof, MDI), tolylene diisocyanate (eg, 2,4- or 2,6-tolylene diisocyanate or mixtures thereof, TDI), 3,3′-dimethoxybiphenyl-4,4′-diisocyanate, 1, 5-na Examples thereof include phthalene diisocyanate (NDI), phenylene diisocyanate (m- or p-phenylene diisocyanate or a mixture thereof), 4,4'-diphenyl diisocyanate, 4,4'-diphenyl ether diisocyanate, and the like.

Examples of polyisocyanate derivatives include multimers of the above polyisocyanates (for example, dimers, trimers (for example, isocyanurate-modified products, iminooxadiazinedione-modified products), pentamers, and 7-mers). ), Allophanate-modified products (for example, allophanate-modified products generated from the reaction of the polyisocyanate with a low molecular weight polyol described later), polyol modified products (for example, generated from the reaction of the polyisocyanate with a low molecular weight polyol described below) Polyol modified products (alcohol adducts, etc.), biuret modified products (for example, biuret modified products produced by reaction of the above polyisocyanate with water or amines), urea modified products (for example, the above polyisocyanate and diamine) Modified with urea, etc.), oxa Azinetrione-modified products (for example, oxadiazinetrione produced by the reaction of the polyisocyanate and carbon dioxide), carbodiimide-modified products (carbodiimide-modified products produced by the decarboxylation condensation reaction of the polyisocyanate), uretdione-modified products, Examples include modified uretonimine, polymethylene polyphenyl polyisocyanate (for example, crude MDI, polymeric MDI) and the like.

Examples of the polyol component include high molecular weight polyols and low molecular weight polyols, which may be used alone or in combination of two or more.
The high molecular weight polyol is a compound having two or more hydroxyl groups and a number average molecular weight of 1,000 or more. For example, polyether polyol, polyester polyol, polyether ester polyol, polycarbonate polyol, polyurethane polyol, epoxy polyol, vegetable oil polyol, polyolefin polyol, An acrylic polyol, a vinyl monomer modified polyol, etc. are mentioned.

The low molecular weight polyol is a compound having two or more hydroxyl groups and having a number average molecular weight of less than 1000. For example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, 1,5-pentanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2,2,2-trimethylpentanediol, 3,3- Dimethylol heptane, alkane (C7-20) diol, cyclohexanedimethanol (eg, 1,3- or 1,4-cyclohexanedimethanol or mixtures thereof), hydrogenated bisphenol A, 1,4-dihydroxy-2-butene 2,6-dimethyl-1-octene-3,8- Dihydric alcohols such as all, bisphenol A, diethylene glycol, triethylene glycol and dipropylene glycol; trihydric alcohols such as glycerin, trimethylolpropane and triisopropanolamine; A pentahydric alcohol such as xylitol; a hexahydric alcohol such as sorbitol, mannitol, allitol, iditol, alditol, altritol, inositol, dipentaerythritol; a seven-valent alcohol such as perseitol; an octahydric alcohol such as sucrose; And monohydric alcohols.
Examples of the low molecular weight polyol include polyether polyols, polyester polyols, and polyether ester polyols having low molecular weight (number average molecular weight of less than 1000).

Examples of the blowing agent include water, halogen-substituted aliphatic hydrocarbon blowing agents (for example, trichlorofluoromethane, dichlorodifluoromethane, trichloroethane, trichloroethylene, tetrachloroethylene, methylene chloride, trichlorotrifluoroethane, dibromotetrafluoroethane, tetrachloride). Carbon, etc.).
The foaming agents can be used alone or in combination of two or more.

The composition for obtaining a polyurethane foam may contain a catalyst as another component, for example.
Examples of the catalyst include triethylamine, triethylenediamine, N-methylmorpholine, bis (2-dimethylaminoethyl) ether, tris (dimethylaminopropyl) hexahydro-S-triazine, 1,4-diazabicyclo [2.2.2. Amine-based catalysts such as tertiary amines such as octane; quaternary ammonium salts such as tetraethylhydroxylammonium; imidazoles such as imidazole and 2-ethyl-4-methylimidazole; Further, as the catalyst, in addition to the above-described amine catalyst, for example, an organic tin compound such as tin acetate, tin octylate, dibutyltin dilaurate, and dibutyltin chloride; an organic lead compound such as lead octylate and lead naphthenate; naphthenic acid Organometallic catalysts such as organic nickel compounds such as nickel;
The catalysts can be used alone or in combination of two or more.

Other components contained in the composition for obtaining the polyurethane foam include, for example, a foam stabilizer, a flame retardant, a viscosity reducer, an antiaging agent, and a pigment in addition to the above catalyst.

<Method for producing laminate>
In the production of the laminate, each layer may be formed separately and then laminated, or each layer may be formed sequentially while being laminated.
For example, when manufacturing the laminated body 10, you may laminate | stack each obtained layer after forming the low ventilation A layer 12, the high ventilation B layer 14, the low ventilation C layer 16, and the high ventilation D layer 18, respectively. Further, for example, after the formation of the low air permeability A layer 12, the high air permeability B layer 14 is formed on the low air permeability A layer 12, and the low air permeability C layer 16 and the high air permeability D layer 18 are similarly formed sequentially. Good.

The bonding method between the layers differs depending on the material of the layer. For example, bonding using an adhesive (for example, hot-melt adhesive, urethane-based adhesive, etc.), thermal fusion (for example, heat treatment, Heat embossing, ultrasonic fusion, etc.), mechanical entanglement (eg, needle punch, water jet, etc.) and the like.
In addition, the laminated body may be subjected to secondary processing such as printing, coating, heat treatment, and shaping as long as the object of the present disclosure is not impaired.

<Use of laminate>
As described above, since the laminated body 10 exhibits excellent sound absorption over a wide frequency range, it is particularly suitable for use as a sound absorbing material, but is not limited thereto, and may be used for other uses such as a heat insulating material and a filter. Good.

[Sound absorbing material]
The sound absorbing material according to the present embodiment includes the above-described laminate. Specifically, for example, the sound-absorbing material including the laminate 10 shown in FIG. 1 may be a sound-absorbing material composed of the laminate 10, and the surface 19 side of the laminate 10 is attached to a base material or the like. A sound absorbing material may be used. In the sound-absorbing material including the laminated body 10, excellent sound-absorbing properties can be obtained over a wide frequency range by installing the laminated body 10 so that the low air permeability A layer 12 side is on the sound incident side.

Hereinafter, the present disclosure will be described more specifically based on examples, but the present disclosure is not limited to these examples.

The physical property values and the like in Examples, Reference Examples and Comparative Examples were measured by the following methods.
(1) Weight per unit area (g / m ² )
Ten samples for basis weight measurement with a machine direction (MD) of 100 mm × lateral direction (CD) of 100 mm were cut out, and an average value was calculated from these 10 samples for basis weight measurement.

(2) Thickness (mm)
With respect to the ten samples for basis weight measurement, the thicknesses at a total of five locations at the center and at the four corners were measured, and the average value at a total of 50 locations was calculated. For the thickness measurement, a thickness gauge having a load of 7 gf / cm ² (measuring element diameter of 50 mmφ) was used.

(3) Air permeability (cc / cm ² / sec)
For a total of five locations at the center and four corners of the measurement sample (100 mm × 100 mm), the air flow rate at a pressure difference of 125 Pa was measured according to JIS L1096 using a Frazier type tester, and the average value was obtained.

(4) Sound absorption rate (sound absorption performance)
A 29 mmφ circular test piece was taken from the obtained laminate, and a plane incident test piece at a frequency of 1000 to 6400 Hz was used in accordance with ASTM E 1050 using a normal incidence sound absorption measuring device (TYPE 4206 manufactured by Brüel & Care). The normal incident sound absorption coefficient when the sound wave was incident vertically was measured. The sound absorption coefficient at 1000 Hz and 5000 Hz was determined from the obtained sound absorption coefficient curve at 1000 to 6400 Hz. In addition, the sound absorption rate shown in Table 1 is a value where “1” is set when all incident sounds are absorbed.

(5) Average fiber diameter of nonwoven fabric (μm)
About the obtained nonwoven fabric, a photograph with a magnification of 1000 times was taken using an electron microscope “S-3500N” manufactured by Hitachi, Ltd., and 100 fibers were arbitrarily selected from the taken pictures, and the width of the fibers ( Diameter) was measured, and the average fiber diameter was calculated based on the number average.

(6) Density of foam (kg / m ³ )
The density of the foam was measured in accordance with ASTM D792 Method A (submersion method).

[Example 1]
<Preparation of each layer>
As the highly air-permeable B layer 14 (second layer) and the highly air-permeable D layer 18 (fourth layer) of the laminate 10, a foamed urethane sheet (manufactured by INOAC, product name: ECS10, density: 22 kg / m ³ ) is used. Prepared each. The basis weight (“weight per unit” in Table 1, unit: g / m ² ) and air permeability (“aeration” in Table 1) in the urethane sheet (“second layer” and “fourth layer” in Table 1), The unit (cc / cm ² / sec) and the thickness (“thickness” in Table 1, unit: mm) are shown in Table 1.
As the low air permeability A layer 12 (first layer) and the low air permeability C layer 16 (third layer) of the laminate 10, a melt blown nonwoven fabric (average fiber diameter: 1 μm) was produced as follows. The basis weight (“weight per unit” in Table 1, unit: g / m ² ) and air permeability (“aeration” in Table 1) of the obtained melt blown nonwoven fabric (“first layer” and “third layer” in Table 1) “, Unit: cc / cm ² / sec), and thickness (“ thickness ”in Table 1, unit: mm) are shown in Table 1.

A propylene homopolymer (melt flow rate: 1550 g / 10 min, melting point 157 ° C., hereinafter referred to as “PP”) was used as the thermoplastic resin, and the thermoplastic resin was used as it was as the thermoplastic resin composition.
A meltblown nonwoven fabric was obtained using a meltblown nonwoven fabric production apparatus equipped with a meltblown spinning nozzle having a nozzle hole diameter of 0.20 mm as a nozzle. Specifically, a fiber obtained by extruding a thermoplastic resin composition at 300 ° C. using the melt blown nonwoven fabric manufacturing apparatus and extruding with heated air (300 ° C., 350 Nm ³ / m / hour) blown from both sides of the spinning nozzle. The fiber was collected at a distance of 20 cm from the spinning nozzle to obtain a meltblown nonwoven fabric.

<Manufacture of laminates>
A spray type adhesive (manufactured by 3M, product name: spray paste 55) was used for bonding the prepared layers.
Specifically, first, an adhesive was spread on the surface of the urethane sheet to be the high air permeability D layer 18 (fourth layer), and the melt blown nonwoven fabric to be the low air permeability C layer 16 (third layer) was stacked. Similarly, an adhesive was spread on the surface of the melt blown nonwoven fabric to be the low air permeability C layer 16 (third layer), and a urethane sheet to be the high air permeability B layer 14 (second layer) was stacked. Furthermore, the melt-blown nonwoven fabric used as the low air-permeation A layer 12 (1st layer) was piled up by spraying an adhesive agent on the surface of the urethane sheet used as the high air-permeation B layer 14 (second layer).

As described above, a laminate of Example 1 was obtained in which four layers were laminated via an adhesive.
The basis weight (“weight per unit” in Table 1, unit: g / m ² ) and air permeability (“aeration” in Table 1, unit: cc / cm) in the entire laminate (“total” in Table 1) ² / sec) and thickness ("thickness" in Table 1, unit: mm) are shown in Table 1.
The sound absorption performance of the obtained laminate is shown in Table 1 (“Sound Absorption Rate” in Table 1).
Furthermore, the frequency dependence of the sound absorption coefficient in the laminate of Example 1 is shown in FIG. In addition, the vertical axis | shaft of the graph shown in FIG. 2 is a sound absorption rate, and a horizontal axis is a frequency (Hz).

[Example 2]
Needle punched nonwoven fabric (average fiber diameter: 30 μm) obtained by the following method as the high air permeability B layer 14 (second layer) and high air permeability D layer 18 (fourth layer) of the laminate 10 instead of the urethane sheet A laminate was obtained in the same manner as in Example 1 except that was used. The basis weight (“weight per unit” in Table 1, unit: g / m ² ) and air permeability (“in the“ second layer ”and“ fourth layer ”in Table 1), air permeability (“ Table 1 shows “aeration”, unit: cc / cm ² / sec), and thickness (“thickness” in Table 1, unit: mm).
The basis weight (“weight per unit” in Table 1, unit: g / m ² ) and air permeability (“aeration” in Table 1, unit: cc / cm) in the entire laminate (“total” in Table 1) ² / sec) and thickness ("thickness" in Table 1, unit: mm) are shown in Table 1.
The sound absorption performance of the obtained laminate is shown in Table 1 (“Sound Absorption Rate” in Table 1).
In addition, the said needle punch nonwoven fabric was manufactured as follows.
A needle punched nonwoven fabric was obtained by forming polyethylene terephthalate fibers (hereinafter also referred to as “PET short fibers”) having an average fiber diameter of 20 μm and an average fiber length of 50 mm into a nonwoven fabric sheet using a needle punch machine.

[Example 3]
As the high air permeability B layer (second layer), the high air permeability D layer (fourth layer), and the high air permeability F layer (sixth layer) in the laminate having the six-layer structure, the thickness is 13 mm and the basis weight is 286 g / m ^2. A urethane sheet (Inoac, product name: ECS) having an air permeability of 166 cc / cm ² / sec was prepared.
As the low air permeability A layer (first layer), the low air permeability C layer (third layer), and the low air permeability E layer (fifth layer) in the laminate of 6 layers, the thickness is 0.1 mm, and the basis weight is 10 g / A meltblown nonwoven fabric with m ² and air permeability of 7 cc / cm ² / sec was prepared. This melt blown nonwoven fabric is the same as the first layer and the third layer of Example 1.
In the same manner as in Example 1, the first to sixth layers were laminated in this order via an adhesive to obtain a laminate consisting of all six layers. The sound absorption performance of the obtained laminate of Example 3 is shown in Table 1 (“Sound Absorption Rate” in Table 1).

[Comparative Example 1]
As the highly breathable layer 114 (second layer) of the laminate 110 shown in FIG. 3, a urethane sheet (manufactured by INOAC, product name: ECS) similar to the highly breathable layer of Example 1 except for the thickness and basis weight was prepared. The basis weight (“weight per unit” in Table 1, unit: g / m ² ) and air permeability (“aeration” in Table 1, unit: cc / cm ² ) in a urethane sheet (“second layer” in Table 1) / Sec) and thickness ("thickness" in Table 1, unit: mm) are shown in Table 1.
Moreover, the melt-blown nonwoven fabric similar to the low ventilation layer of Example 1 was produced as the low ventilation layer 112 (1st layer) of the laminated body 110 shown in FIG. The basis weight (“weight per unit” in Table 1, unit: g / m ² ) and air permeability (“aeration” in Table 1, unit: cc / in) in the obtained melt blown nonwoven fabric (“first layer” in Table 1) cm ¹ / sec) and thickness (“thickness” in Table 1, unit: mm) are shown in Table 1.

Two layers were bonded in the same manner as in Example 1.
The basis weight (“weight per unit” in Table 1, unit: g / m ² ) and air permeability (“aeration” in Table 1, unit: cc / cm) in the entire laminate (“total” in Table 1) ² / sec) and thickness ("thickness" in Table 1, unit: mm) are shown in Table 1. In addition, the oblique line in Table 1 indicates that the corresponding layer is not included, and so on.
The sound absorption performance of the obtained laminate is shown in Table 1 (“Sound Absorption Rate” in Table 1).
Furthermore, the frequency dependence of the sound absorption coefficient in the laminate of Comparative Example 1 is shown in FIG.

[Comparative Example 2]
As the low ventilation layer 112 (first layer) of the laminate 110 shown in FIG. 3, lamination was performed in the same manner as in Comparative Example 1 except that a melt blown nonwoven fabric similar to the low ventilation layer of Example 1 was prepared except for thickness and basis weight. Got the body.
The basis weight (“weight per unit” in Table 1, unit: g / m ² ) and air permeability (“aeration” in Table 1, unit: cc / in) in the obtained melt blown nonwoven fabric (“first layer” in Table 1) cm ¹ / sec) and thickness (“thickness” in Table 1, unit: mm) are shown in Table 1.
In addition, the basis weight (“weight per unit” in Table 1, unit: g / m ² ) and air permeability (“aeration” in Table 1, unit: cc) in the entire obtained laminate (“total” in Table 1) / Cm ² / sec) and thickness (“thickness” in Table 1, unit: mm) are shown in Table 1.
Furthermore, the sound absorption performance of the obtained laminate is shown in Table 1 (“Sound Absorption Rate” in Table 1).

[Comparative Example 3]
As the high air permeability layer 114 (second layer) of the laminate 110 shown in FIG. 3, except that a needle punched nonwoven fabric similar to the high air permeability layer of Example 2 was prepared except for thickness and basis weight, it was the same as in Comparative Example 1. A laminate was obtained.
The basis weight (“weight per unit” in Table 1, unit: g / m ² ), air permeability (“aeration” in Table 1, unit: cc) in the obtained needle punched nonwoven fabric (“second layer” in Table 1) / Cm ² / sec) and thickness (“thickness” in Table 1, unit: mm) are shown in Table 1.
In addition, the basis weight (“weight per unit” in Table 1, unit: g / m ² ) and air permeability (“aeration” in Table 1, unit: cc) in the entire obtained laminate (“total” in Table 1) / Cm ² / sec) and thickness (“thickness” in Table 1, unit: mm) are shown in Table 1.
Furthermore, the sound absorption performance of the obtained laminate is shown in Table 1 (“Sound Absorption Rate” in Table 1).

[Comparative Example 4]
A single-layer nonwoven fabric sound absorbing material (manufactured by 3M, product name: TAI4027) was used as a single layer.
The basis weight (“weight per unit” in Table 1, unit: g / m ² ) and air permeability (“aeration” in Table 1, unit: cc / cm) in the entire single-layer nonwoven fabric sound absorbing material (“total” in Table 1) ² / sec) and thickness ("thickness" in Table 1, unit: mm) are shown in Table 1.
Furthermore, the sound absorption performance of the obtained laminate is shown in Table 1 (“Sound Absorption Rate” in Table 1).

[Comparative Example 5]
Two layers of single-layer nonwoven fabric sound-absorbing material (manufactured by 3M, product name: TAI4027) were used, and two layers were bonded in the same manner as in Example 1 to obtain a laminate.
The basis weight (“weight per unit” in Table 1, unit: g / m ² ) and air permeability (“aeration” in Table 1, unit: cc / cm) in the entire laminate (“total” in Table 1) ² / sec) and thickness ("thickness" in Table 1, unit: mm) are shown in Table 1.
The sound absorption performance of the obtained laminate is shown in Table 1 (“Sound Absorption Rate” in Table 1).
Furthermore, the frequency dependence of the sound absorption coefficient in the laminate of Comparative Example 5 is shown in FIG.

As shown in Table 1 and FIG. 2, it can be seen that the example shows excellent sound absorption over a wide frequency range as compared with the comparative example.

Since the laminate of the present disclosure exhibits excellent sound absorption over a wide frequency range, it is a transport device for automobiles, trains, ships, aircraft, etc .; vacuum cleaner, washing machine, refrigerator, freezer, dryer, mixer, air conditioner, air cleaner Electric appliances such as machines; office automation equipment such as copiers, facsimiles, personal computers, and printing machines; houses such as wall materials, ceiling materials, floor materials, and the like, and can be used for applications that require sound absorbing materials. Among these, in applications where the thickness of the entire sound absorbing material is limited (for example, automobiles and the like), the sound absorption can be enhanced over a wide frequency range without changing the overall thickness, and therefore the laminate of the present disclosure is particularly useful. . In addition, in electric vehicle applications, since a wide range of sound absorption characteristics is required from low road noise to high motor sound, the laminate of the present disclosure having excellent sound absorption over a wide frequency range is particularly useful.

The disclosure of Japanese Patent Application No. 2017-072285 filed on March 31, 2017 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.

Claims

A first layer having an air permeability of 1 cc / cm 2 / sec or more and less than 30 cc / cm 2 / sec;
A second layer having an air permeability of 30 cc / cm 2 / sec to 1000 cc / cm 2 / sec,
A third layer having an air permeability of 1 cc / cm 2 / sec or more and less than 30 cc / cm 2 / sec;
A fourth layer having an air permeability of 30 cc / cm 2 / sec to 1000 cc / cm 2 / sec,
Are stacked in this order.
The laminate according to claim 1, wherein at least one of the first layer and the third layer is a nonwoven fabric, a porous film, a woven fabric, or a foam.
The laminate according to claim 1 or 2, wherein at least one of the second layer and the fourth layer is a nonwoven fabric, a woven fabric, or a foam.
The laminate according to any one of claims 1 to 3, wherein a thickness of the first layer and a thickness of the third layer are 0.1 mm or more and 2 mm or less, respectively.
The laminate according to any one of claims 1 to 4, wherein a thickness of the second layer and a thickness of the fourth layer are 10 mm or more and 50 mm or less, respectively.
A sound-absorbing material comprising the laminate according to any one of claims 1 to 5.