WO2022040386A1

WO2022040386A1 - A layered liquid applied sound damper

Info

Publication number: WO2022040386A1
Application number: PCT/US2021/046624
Authority: WO
Inventors: Nicholas Xuanlai FANG; John David CAMPBELL; Shahrzad Ghaffari MOSANENZADEH; Joshua C. SPEROS; Sean Raymond GEORGE; Karl R. NICHOLAS
Original assignee: BASF SE; Massachusetts Institute of Technology
Current assignee: BASF SE; Massachusetts Institute of Technology
Priority date: 2020-08-19
Filing date: 2021-08-19
Publication date: 2022-02-24
Anticipated expiration: 2023-02-19

Abstract

The present technology provides an article of manufacture and methods of making the article that includes a damping formulation deposited on a substrate, wherein the damping formulation includes a first layer comprising a first composition and a second layer comprising a second composition and the second composition has a stiffness less than 10-times greater than the first composition. The article exhibits greater vibrational and/or acoustic sound damping than the same amount of the damping formulation comprising a mixture of the first composition and the second composition deposited in a single layer on the substrate as measured by a composite loss factor.

Description

A LAYERED LIQUID APPLIED SOUND DAMPER FIELD

[0001] The present technology is generally related to liquid-applied sound damping ("LASD") coatings, and methods of their application and preparation, and their use in downstream applications.

SUMMARY

[0002] In one aspect, the present technology is directed to an article of manufacture that includes a damping formulation deposited on a substrate, wherein the damping formulation includes a first layer and a second layer and the first layer includes a first composition and the second layer includes a second composition having a stiffness less than 10-times greater than the first composition. The article exhibits greater vibrational and/or acoustic sound damping than the same amount of the damping formulation that includes a mixture of the first composition and the second composition deposited in a single layer on the substrate as measured by a composite loss factor ("CLF"). In some embodiments, the article exhibits an average of at least, about 20% more vibrational and/or acoustic sound damping than the same amount of the damping formulation comprising a mixture of the first composition and the second composition deposited in a single layer on the substrate.

[0003] In another aspect, the present technology is directed to a method of damping sound that includes applying/depositing on the substrate the first layer of the damping formulation and applying/depositing the second layer of the damping formulation on the first layer as disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] FIG. 1A is a schematic of panel test setup and FIG. IB is graph illustrating the method of determining CLF using frequency response function and half-power-band width, according to the examples.

[0005] FIG. 2 is a photo of test bars A-F showing their varying total thickness and layer thicknesses, according to the examples.

[0006] FIG. 3 is a graph illustrating the composite loss factor ("CLF") for bars A-F at varying frequencies, according to the examples.

[0007] FIG. 4A is an illustration of a first test bar with two LASD layers deposited (high T_g layered on top of a low T_g) and a second bar with a single layer of a 1:1 blend of the same LASD formulas. FIGS. 4B-4D are graphs illustrating the CLF for each bar at varying temperatures and resonance frequencies, according to the examples. [0008] FIG. 5A is an illustration of a first test bar with two LASD layers deposited (normal LASD layered on top of LASD with expanded microspheres) and a second bar with a single layer of a 1:1 blend of the same LASD formulas. FIGS. 5B-5D are graphs illustrating the CI..F for each bar at varying temperatures and resonance frequencies, according to the examples.

DETAILED DESCRIPTION

[0009] Various embodiments are described hereinafter. It should be noted that the specific embodiments are not intended as an exhaustive description or as a limitation to the broader aspects discussed herein. One aspect described in conjunction with a particular embodiment is not necessarily limited to that embodiment and can be practiced with any other embodiment(s). [0010] As used herein, "about" will be understood by persons of ordinary skill in the art and will vary to some extent depending upon the context in which it is used. If there are uses of the term which are not clear to persons of ordinary skill in the art, given the context in which it is used, "about" will mean up to plus or minus 10% of the particular term.

[0011] The use of the terms "a" and "an" and "the" and similar referents in the context of describing the elements (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein may be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the embodiments and does not pose a limitation on the scope of the claims unless otherwise stated. No language in the specification should be construed as indicating any non-claimed element as essential.

[0012] Automobile manufacturers are under increasing pressure (i.e. Corporate Average Fuel Economy ("CAFE" standards)) to reduce weight in order to improve fuel efficiency. However, reducing vehicle weight increases susceptibility to acoustic and mechanical vibration. These combine to decrease the overall passenger experience. Therefore, sound and vibration damping treatments are applied to the automotive body. The articles, methods, and uses disclosed herein may be employed in wide variety of applications, including, but not limited to, inside the body of motor vehicles to reduce the structure borne noise. Acoustic and mechanical vibration is also needed for other objects and industries such as machinery and appliances. The most prevalent damping technology is referred to as liquid-applied sound damping (LASD). Traditionally, LASD formulations are robotically and strategically applied as a single continuous coating of a heavily formulated waterborne system to the interior of a vehicle body. These formulations are complex, but contain two principle components: a waterborne emulsion polymer and a cost- effective dense filler (e.g. CaCO₃). The polymer serves to bind the dense filler together in the dried coating and damps vibration by nature of its viscoelastic properties. The filler is largely present to add mass (a traditional damping technique) and to reduce the cost of the formulation. [0013] It has now been found that improved sound damping can be achieved through the use of layers of different stiffness. Accordingly, described herein is an article of manufacture that includes a damping formulation deposited on a substrate, wherein the damping formulation includes a first layer and a second layer and the first layer includes a first composition and the second layer includes a second composition having a stiffness less than 10-times greater than the first composition. The damping formulation is configured to dampen vibrational and/or acoustic sound from and/or through the substrate. The article exhibits greater vibrational and/or acoustic sound damping than the same amount of the damping formulation included a mixture of the first composition and the second composition deposited in a single layer on the substrate as measured by a composite loss factor ("CLF").The approach described herein would not require new- material development, but instead, damping could be improved simply by applying pre-existing formulation(s) in layers of varying stiffness. In some embodiments, the stiffness may vary by using different polymers (e.g., a polymer with a lower glass transition temperature (T_g) for lower stiffness and a polymer with a higher T_g for higher stiffness), different density formulations (e.g., for a lower density formulation more filler or lower density filler may be used), and polymer crosslinking. For example, the damping formulation may be any formulation disclosed in WO 2019/099372, WO 2017/062878, US Pub. Appl. Nos. 2019/0016918, 2018/0030263, 2016/0035339, 2009/0045008, and US Patent No. 7,186,442, each of which is incorporated herein by reference. The damping formulation may be a liquid-applied sound damping ("LASD") formulation. In some embodiments, the damping formulation may be an aqueous- based formulation.

[0014] In some embodiments, the damping formulation is a vibration damping formulation, an acoustic damping formulation, or both a vibration and an acoustic damping formulation.

[0015] In some embodiments, the article with the damping formulation including a first layer and a second layer exhibits an average of at least about 20% more vibrational and/or acoustic sound damping based on CLF than the same amount of the damping formulation including a mixture of the first and second compositions deposited in a single layer on the substrate. In some embodiments, the article exhibits an average of at least about 30%, at least about 40%, at least about 50%, or at. least about 60% more vibrational and/or acoustic sound damping based on CLF than the same amount of the damping formulation including a mixture of the first and second compositions deposited in a single layer on the substrate.In some embodiments, the CLF is measured at about 100 to about 800 Hz (including about 100 Hz, about 125 Hz, about 160 Hz, about 200 Hz, about 250 Hz, about 315 Hz, about 400 Hz, about 500 Hz, about 630 Hz, and/or 800 Hz determined for 1/3 octave band frequencies ("OBF").

[0016] In some embodiments, the damping formulation deposited on the substrate may include two or more layers (e.g., 2, 3, or 4 layers). The first layer preferably includes a first composition that includes a first polymeric material and the second layer preferably includes a second composition that includes a second polymeric material. In some embodiments, the first polymeric material and the second polymeric material are the same. When the first and second polymeric materials are the same, then polymers may include the same monomeric units but have different molecular weights. In other embodiments, when the first and second polymeric materials are the same, the polymers may include the same monomeric units and have the same molecular weights. In this embodiment, the fillers in the first and second compositions may differ (e.g., different types of fillers and/or different amounts of fillers). In other embodiments, the first polymeric material and the second polymeric material are different.

[0017] Preferably, the first layer is below the second layer (i.e., the first layer is the lower layer and the second layer is the upper layer). In some embodiments, the first layer may be deposited on the substrate. In some embodiments, the second layer may be deposited on the first layer such that the second layer is in direct contact with the first layer. In some embodiments, the first layer is uniformly deposited on the substrate and the second layer is uniformly deposited on the first layer.

[0018] The second composition has a Young's Modulus stiffness factor less than 10-times greater than the first composition (e.g., the second composition may have a Young's Modulus (E’) less than 1.0 x 10⁹ MPa compared to the first composition) .In some embodiments, the second composition has a Young's Modulus stiffness factor less than 10-times greater than the first composition (e.g., the second composition may have a Young's Modulus (E') less than 1.0 x 10⁹ Pa compared to the first composition).In some embodiments, the second composition has a stiffness factor less than 8-times greater, less than 5-times greater, less than 3-times greater, or less than 2-times greater than the first composition. In some embodiments, the first composition has a stiffness of about 5 MPa to about 1000 MPa and the second composition has a stiffness of about 1000 MPa to about 10,000 MPa. In some embodiments, the first composition has a stiffness of about 5 MPa to about 800 MPa, about 5 MPa to about 500 MPa, or about 5 MPa to about 300 MPa. In some embodiments, the second composition has a stiffness of about 1100 MPa to about 8000 MPa, about 1200 MPa to about 7000 MPa, or about 1400 MPa to about 6000 MPa. In some embodiments, the first composition has a stiffness of about 10 MPa to about 100 MPa and the second composition has a stiffness of about 1500 MPa to about 5000 MPa.

[0019] In some embodiments, the first composition has a lower glass transition temperature than the second composition. In some embodiments, the first composition may have a glass transition temperature (T_g) from about -20 °C to about 10 °C. In some embodiments, the first composition may have a glass transition temperature (Tg) from about -10 °C to about 10 °C or about -5 °C to about 5 °C. In some embodiments, the second composition may have a glass transition temperature (T_g) from about 10 °C to about 40 °C. In some embodiments, the second composition may have a glass transition temperature (Tg) from about 15 °C to about 30 °C or 15 °C to about 25 °C.

[0020] In some embodiments, the first composition has a lower density than the second composition. In some embodiments, the first composition may have a density at least about 1.5 times lower than the second composition. In some embodiments, the first composition may have a density at least about 2 times, about 2.5 times, or about 3 times lower than the second composition. In some embodiments, the first composition may have a density from about 500 kg/m³ to about 1500 kg/m³. In some embodiments, the first composition may have a density from about 600 kg/m³ to about 1400 kg/m³. In some embodiments, the first composition may have a density from about 700 kg/m³ to about 1300 kg/m³. In some embodiments, the first composition may have a density from about 800 kg/m³ to about 1200 kg/m³.In some embodiments, the second composition may have a density from about 1500 kg/m³ to about 2500 kg/m³. In some embodiments, the second composition may have a density from about 1600 kg/m³ to about 2400 kg/m³.In some embodiments, the second composition may have a density from about 1700 kg/m³ to about 2300 kg/m³.In some embodiments, the second composition may have a density from about 1800 kg/m³ to about 2200 kg/m³.

[0021] In some embodiments, the first composition has greater porosity than the second composition. In some embodiments, the first composition has a low density and high elastic modulus constrained by a dense second composition. In some embodiments, the damping formulation includes a porous lower layer constrained with a solid upper layer both made of LASD material. In some embodiments, the lower layer and the upper layer may both be made of pre-existing formulations (e.g. high/low density or high/low modulus).

[0022] In some embodiments, the first polymeric material and the second polymeric material may be the same or different and may be any polymeric material as long as the respective first composition and second composition have at least one of the physical properties described herein. For example, the first composition and second composition have at least the Young's Modulus, T_g, and/or density described herein. In a nonlimiting example, the polymeric material may be an acrylic based polymeric material.

[0023] In some embodiments, the damping formulation may also include a filler. The filler may be in the first composition, the second composition, or both the first and second compositions. In some embodiments, the first composition and the second composition may include the same filler. Examples of a filler include, but are not limited to, calcium carbonate, barium sulfate, glass filler, magnesium carbonate, microsphere (e.g., plastic or glass), mica, or a combination of two or more thereof. In some embodiments, the filler may include calcium carbonate.In some embodiments, the filler may include microsphere including expanded microspheres. In some embodiments, the first composition and the second composition may include 0 to about 85 wt% filler (e.g., 0 to about 75 wt%, 0 to about 50 wt%, 0 to about 25 wt%, 0 to 15 wt%, 5 to about 75 vrt%, 10 to about 65 vrt%, 20 to about 60 vrt%, or 30 to 50 wt%). In some embodiments, the first composition may include about 1.5-times or greater filler than the second composition. [0024] The damping formulation may also include other additives such as a defoaming agent, a rheological modifier, an emulsifying agent, a biocide, or a mixture of any two or more thereof. The damping formulation can also include pigments for aesthetic purposes. The pigments can be, but are not limited to, black or white pigments.

[0025] In some embodiments, the damping formulation may have a thickness of about 0.5 mm to about 20 mm, about 0.5 mm to about 10 mm, about 1.0 mm to about 9.0 mm, about 2.0 mm to about 8.0 mm, about 2.0 mm to about 6.0 mm, or about 1 mm to about 5 mm. In some embodiments, the first layer may have a thickness of about 0.5 mm to about 10 mm, about 1.0 mm to about 9.0 mm, about 2.0 mm to about 8.0 mm, about 2.0 mm to about 6.0 mm, or about 1 mm to about 5 mm. In some embodiments, the second layer may have a thickness of about 0.5 mm to about 10 mm, about 1.0 mm to about 9.0 mm, about 2.0 mm to about 8.0 mm, about 2.0 mm to about 6.0 mm, or about 1 mm to about 5 mm. In some embodiments, the first layer and the second layer may have about the same thickness. In other embodiments, the first layer may be thicker than the second layer or the second layer may be thicker than the first layer. [0026] The substrate of the present disclosure may be an automotive (e.g., vehicle), airplane, home appliances (e.g., dishwasher or washing machine), building material, computer, vacuum cleaner, HVAC system, and/or flooring. In some embodiments, the substrate may be a vehicle. [0027] Other advantages that may be imparted to the article by the damping formulation include, but are not limited to, optimization of barrier properties over the sound damping formulation, good flexibility, and ease of application. Further advantages include but are not limited to mass reduction/optimization.

[0028] In another aspect, a method of damping sound that includes applying to the substrate the first layer of the damping formulation as disclosed herein and the second layer of damping formulation as disclosed herein. As such, the method may include applying to the substrate the first layer of the damping formulation and applying the second layer of the damping formulation to the first layer. In some embodiments, the damping formulation may be in liquid form during the application. In some embodiments, the damping formulation has a viscosity of about 5000 to about 300,000 cps (centipoise) (including viscosities of about 10,000 to about 200,000 cps, about 10,000 to about 150,000 cps, or about 10,000 to about 100,000 cps). Methods to measure viscosity will be well known to a person skilled in the art.

Exemplary Embodiments

[0029] Embodiment 1 is an article of manufacture comprising a damping formulation deposited on a substrate, wherein the damping formulation is configured to dampen vibrational and/or acoustic sound from and/or through the substrate: wherein: the damping formulation comprises a first layer and a second layer, wherein: the first layer comprises a first composition and the second layer comprises a second composition; and the second composition has a stiffness less than 10-times greater than the first composition; and the article exhibits greater vibrational and/or acoustic sound damping than the same amount of the damping formulation comprising a mixture of the first composition and the second composition deposited in a single layer on the substrate as measured by a composite loss factor. [003030] Embodiment 2 is the article of embodiment 1, wherein the first composition comprises a first polymeric material and the second composition comprises a second polymeric material and the first polymeric material and the second polymeric material are the same.

[003131] Embodiment 3 is the article of embodiment 1, wherein the first composition comprises a first polymeric material and the second composition comprises a second polymeric material and the first polymeric material and the second polymeric material are different.

[003232] Embodiment 4 is the article of any one of embodiments 1-3, wherein the damping formulation comprises a filler, a defoaming agent, a rheological modifier, a emulsifying agent, a biocide, or a mixture of any two or more thereof.

[003333] Embodiment 5 is the article of embodiment 4, wherein the damping formulation comprises the filler.

[003434] Embodiment 6 is the article of embodiment 5, wherein the filler comprises calcium carbonate, microspheres, or a combination thereof.

[003535] Embodiment 7 is the article of embodiment 5 or embodiment 6, wherein the first composition and the second composition comprise the filler.

[003636] Embodiment 8 is the article of any one of embodiments 5-7, wherein the first composition and the second composition comprise the same filler.

[003737] Embodiment 9 is the article of any one of embodiments 1-8, wherein the article exhibits an average of at least about 20% more vibrational and/or acoustic sound damping than the same amount of the damping formulation comprising a mixture of the first composition and the second composition deposited in a single layer on the substrate.

[003838] Embodiment 10 is the article of any one of embodiments 1-9, wherein the article exhibits an average of at least about 30% more vibrational and/or acoustic sound damping than the same amount of the damping formulation comprising a mixture of the first composition and the second composition deposited in a single layer on the substrate.

[003939] Embodiment 11 is the article of any one of embodiments 1-10, wherein the article exhibits an average of at least about 40% more vibrational and/or acoustic sound damping than the same amount of the damping formulation comprising a mixture of the first composition and the second composition deposited in a single layer on the substrate.

[004040] Embodiment 12 is the article of any one of embodiments 1-11, wherein the damping formulation is a vibration damping formulation.

[004141] Embodiment 13 is the article of any one of embodiments 1-12, wherein the second layer is in direct contact with the first layer. [004242] Embodiment 14 is the article of any one of embodiments 1-13, wherein the first layer is uniformly deposited on the substrate and the second layer is uniformly deposited on the first layer.

[004343] Embodiment 15 is the article of any one of embodiments 1-14, wherein the first composition has a lower glass transition temperature than the second composition.

[004444] Embodiment 16 is the article of any one of embodiments 1-15, wherein the first composition has a lower density than the second composition.

[004545] Embodiment 17 is the article of any one of embodiments 1-16, wherein the second composition has a stiffness factor less than 8-times higher than the first composition.

[004646] Embodiment 18 is the article of any one of embodiments 1-17, wherein the second composition has a stiffness factor less than 5-times greater than the first composition.

[004747] Embodiment 19 is the article of any one of embodiments 1-18, wherein the first composition has a stiffness of about 5 MPa to about 1000 MPa and the second composition has a stiffness of about 1000 MPa to about 10,000 MPa.

[004848] Embodiment 20 is the article of any one of embodiments 1-19, wherein the first composition has a stiffness of about 10 MPa to about 100 MPa and the second composition has a stiffness of about 1500 MPa to about 5000 MPa.

[004949] Embodiment 2.1 is the article of any one of embodiments 1-20, wherein the first composition has greater porosity than the second composition.

[005050] Embodiment 22 is the article of any one of embodiments 1-21, wherein the damping formulation has a thickness of about 0.5 mm to about 10 mm.

[005151] Embodiment 23 is the article of any one of embodiments 1-22, wherein the damping formulation has a thickness of about 2.0 mm to about 8.0 mm.

[005252] Embodiment 24 is the article of any one of embodiments 1-23, wherein the first layer has a thickness of about 0.5 mm to about 10 mm and the second layer has a thickness of about 0.5 mm to about 10 mm.

[005353] Embodiment 25 is the article of any one of embodiments 1-24, wherein the first layer has a thickness of about 1 mm to about 5 mm and the second layer has a thickness of about 1 mm to about 5 mm.

[005454] Embodiment 26 is the article of embodiment 24 or embodiment 25, wherein the first layer and the second layer have about the same thickness.

[005555] Embodiment 27 is the article of embodiment 24 or embodiment 25, wherein the first layer is thicker than the second layer. [005656] Embodiment 28 is the article of embodiment 24 or embodiment 25, wherein the second layer is thicker than the first layer.

[005757] Embodiment 29 is the article of any one of embodiments 1-28, wherein the damping formulation is a liquid-applied sound damping formulation.

[005858] Embodiment 30 is the article of any one of embodiments 1-29, wherein the damping formulation is an aqueous-based formulation.

[005959] Embodiment 31 is the article of any one of embodiments 1-30, wherein the substrate is a vehicle.

[006060] Embodiment 32 is a method of damping sound, the method comprising: applying to the substrate the first layer of the damping formulation in any one of embodiments 1-31; and applying the second layer of damping formulation on the first layer in any one of embodiments 1-31.

[006161] Embodiment 33 is the method of embodiment 32, wherein the damping formulation is in liquid, form during the applying.

[006262]The present invention, thus generally described, will be understood more readily by reference to the following examples, which are provided by way of illustration and are not intended to be limiting of the present invention.

EXAMPLES

[006363] Example l.Steel bars (Oberst bars) were tested to determine and compare vibration loss factors over a temperature range of 20 °C to 60 °C. Each bar was clamped into a heavy base (FIG. 1A). A non-contacting transducer excited the free-end of the bar and another non-contacting transducer near the fixed-end of the bar sent output to a processing unit to calculate the CLF. From the excitement measurements, mobility (frequency response function (“FRF”)) data was acquired relative to the force input in 1 Hz bands. Following the A STM E756 guidelines, the CLF was determined from the frequency response function by the half- power-bandwidth method (FIG. 1B) using the following equation:

where CLF is the composite loss factor, E is the Young's modulus, H is the thickness,

is peak width, is peak height, and A is a constant.

[006464] Seven total bars were prepared and tested. Six bars (A-F) were coated with various damping formulations and one bar was left bare. Bars A, C, and D had the same total damping formulation thickness. The bars differed in Bar A including a single layer of low porosity damping formulation, Bar C including two layers of approximately equal thickness with an upper layer of low porosity damping formulation and a lower layer of high porosity damping formulation, and Bar D including two layers of unequal thickness with an upper layer of low porosity damping formulation (about 1/3 of the total damping formulation thickness) and a lower layer of high porosity damping formulation (about 2/3 of the total damping formulation thickness) (FIG. 2). Bars B, E, and F had the same total damping formulation thickness, which was about half the thickness of Bars A, C, and D. The bars differed in Bar B including a single layer of low porosity damping formulation, Bar E including two layers of unequal thickness with an upper layer of low porosity damping formulation (about 2/3 of the total damping formulation thickness) and a lower layer of high porosity damping formulation (about 1/3 of the total damping formulation thickness), and Bar including two layers of unequal thickness with an upper layer of low porosity damping formulation (about 1/3 of the total damping formulation thickness) and a lower layer of high porosity damping formulation (about 2/3 of the total damping formulation thickness) (FIG. 2).

[006565] The loss factor values for each bar are provided in FIG. 3. Bars C and D with two layers provided improved CLF compared to Bar A. Bars E and F with two layers provided improved CLF compared to Bar B at higher frequency.

[006666] Example 2. Two metal bars (Oberst bars) were prepared and tested to determine and compare vibration loss factors. Each bar was rigidly mounted to a fixture and excited as described in Example 1. The first bar had two LASD layers deposited (high T_g (20°C) LASD layered on top of a low T_g (0°C) LASD) and the second bar had a single layer of a 1:1 blend of the same LASD formulas (FIG. 4A). The loss factor values for each bar at varying temperatures are provided in FIGS. 4B-4D at resonance modes of 100-170 Hz (Mode 2), 290-470 Hz (Mode 3), and 650-920 Hz (Mode 4). The bar with two layers provided improved CLF compared to the bar with a single mixed layer at temperatures above 20 °C (i.e., peak damping temperatures).

[006767] Example 3. Two metal bars (Oberst bars) were prepared and tested to determine and compare vibration loss factors. Each bar was rigidly mounted to a fixture and excited as described in Example 1. The first bar had two LASD layers deposited (normal density LASD layered on top of a low density LASD) and the second bar had a single layer of a 1 : 1 blend of the same LASD formulas (FIG. 5A). The loss factor values for each bar at varying temperatures are provided in FIGS. 5B-5D at resonance modes of 100-170 Hz (Mode 2), 290-470 Hz (Mode 3), and 200 Hz. The bar with two layers provided slightly improved CLF compared to the bar with a single mixed layer at temperatures at about and above 20 °C (i.e., at or near peak damping temperatures).

[006868] While certain embodiments have been illustrated and described, it should be understood that changes and modifications can be made therein in accordance with ordinary skill in the art without departing from the technology in its broader aspects as defined in the following claims.

[006969] The embodiments, illustratively described herein may suitably be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. Thus, for example, the terms "comprising," "including," "containing," etc. shall be read expansively and without limitation. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the claimed technology. Additionally, the phrase "consisting essentially of’ will be understood to include those elements specifically recited and those additional elements that do not materially affect the basic and novel characteristics of the claimed technology. The phrase "consisting of" excludes any element not specified.

[007070] The present disclosure is not to be limited in terms of the particular embodiments described in this application. Many modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods and compositions within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods, reagents, compounds, compositions, or biological systems, which can of course vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[007171] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group. [007272] As will be understood by one skilled in the art, for any and all purposes, particularly in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as "up to," "at least," "greater than," "less than," and the like, include the number recited and refer to ranges which can be subsequently broken down into subranges as discussed above.

Finally, as will be understood by one skilled in the art, a range includes each individual member. [007373] All publications, patent applications, issued patents, and other documents referred to in this specification are herein incorporated by reference as if each individual publication, patent application, issued patent, or other document was specifically and individually indicated to be incorporated by reference in its entirety . Definitions that are contained in text incorporated by reference are excluded to the extent that, they contradict definitions in this disclosure.

[007474] Other embodiments are set. forth in the following claims

Claims

CLAIMS What Is Claimed Is:

1. An article of manufacture comprising a damping formulation deposited on a substrate, wherein the damping formulation is configured to dampen vibrational and/or acoustic sound from and/or through the substrate; wherein: the damping formulation comprises a first layer and a second layer, wherein: the first layer comprises a first composition and the second layer comprises a second composition; and the second composition has a stiffness less than 10-times greater than the first composition; and the article exhibits greater vibrational and/or acoustic sound damping than the same amount of the damping formulation comprising a mixture of the first composition and the second composition deposited in a single layer on the substrate as measured by a composite loss factor.

2. The article of claim 1 , wherein the first composition comprises a first polymeric material and the second composition comprises a second polymeric material and the first polymeric material and the second polymeric material are the same.

3. The article of claim 1, wherein the first composition comprises a first polymeric material and the second composition comprises a second polymeric material and the first polymeric material and the second polymeric material are different.

4. The article of any claim 1 , wherein the damping formulation comprises a filler, a defoaming agent, a rheological modifier, a emulsifying agent, a biocide, or a mixture of any two or more thereof.

5. The article of claim 4, wherein the damping formulation comprises the filler.

6. The article of claim 5, wherein the filler comprises calcium carbonate, microspheres, or a com bina ti on thereof .

7. The article of claim 5, wherein the first composition and the second composition comprise the filler.

8. The article of claim 5, wherein the first composition and the second composition comprise the same filler.

9. The article of claim 1 , wherein the article exhibits an average of at least about 20% more vibrational and/or acoustic sound damping than the same amount of the damping formulation comprising a mixture of the first composition and the second composition deposited in a single layer on the substrate.

10. The article of claim 1, wherein the article exhibits an average of at least about 30% more vibrational and/or acoustic sound damping than the same amount of the damping formulation comprising a mixture of the first composition and the second composition deposited in a single layer on the substrate.

11. The article of claim 1 , wherein the article exhibits an average of at least about 40% more vibrational and/or acoustic sound damping than the same amount of the damping formulation comprising a mixture of the first composition and the second composition deposited in a single layer on the substrate.

12. The article of claim 1, wherein the damping formulation is a vibration damping formulation.

13. The article of claim 1, wherein the second layer is in direct contact with the first layer.

14. The article of claim 1 , wherein the first layer is uniformly deposited on the substrate and the second layer is uniformly deposited on the first layer.

15. The article of claim 1, wherein the first composition has a lower glass transition temperature than the second composition.

16. The article of claim 1, wherein the first composition has a lower density than the second composition.

17. The article of claim 1, wherein the second composition has a stiffness factor less than 8- times higher than the first composition.

18. The article of claim 1 , wherein the second composition has a stiffness factor less than 5- times greater than the first composition.

19. The article of claim 1, wherein the first composition has a stiffness of about 5 MPa to about 1000 MPa and the second composition has a stiffness of about 1000 MPa to about 10,000 MPa.

20. The article of claim 1, wherein the first composition has a stiffness of about 10 MPa to about 100 MPa and the second composition has a stiffness of about 1500 MPa to about 5000 MPa.

21. The article of claim 1 , wherein the first composition has greater porosity than the second composition.

22. The article of claim 1 , wherein the damping formulation has a thickness of about 0.5 mm to about 10 mm.

23. The article of claim 1 , wherein the damping formulation has a thickness of about 2.0 mm to about 8.0 mm.

24. The article of claim 1, wherein the first layer has a thickness of about 0.5 mm to about 10 mm and the second layer has a thickness of about 0.5 mm to about 10 mm.

25. The article of claim 1, wherein the first layer has a thickness of about 1 mm to about 5 mm and the second layer has a thickness of about 1 mm to about 5 mm.

26. The article of claim 24, wherein the first layer and the second layer have about the same thickness.

27. The article of claim 24, wherein the first layer is thicker than the second layer.

28. The article of claim 24, wherein the second layer is thicker than the first layer.

29. The article of any claim 1, wherein the damping formulation is a liquid-applied sound damping formulation.

30. The article of claim 1, wherein the damping formulation is an aqueous-based formulation.

31. The article of claim 1 , wherein the substrate is a vehicle.

32. A method of damping sound, the method comprising: applying to the substrate the first layer of the damping formulation in claim 1; and applying the second layer of damping formulation on the first layer in claim 1.

33. The method of claim 32, wherein the damping formulation is in liquid form during the applying.