Sprayable aqueous acoustic damping composition and article thereof

Abstract

The present invention relates to a sprayable aqueous acoustic damping composition comprising a polymer, a filler, and a water-soluble cellulose compound or a water-soluble starch wherein the filler comprises a filler (i) having an average particle size (d50 particle size) of about 7 to 18 [mu] m, and a filler (ii) having an average particle size (d50 particle size) of about 2 to 5 [mu] m.

Description

Technical Field

[0001] This disclosure relates to sprayable waterborne acoustic damping compositions and articles thereof for motor vehicle applications, and more particularly to waterborne acoustic damping compositions with good crack resistance. These waterborne acoustic damping compositions can be used, for example, in automotive industry applications. Background Technology

[0002] Sound damping materials, such as manually applied sound-absorbing patches using asphalt pads, have helped suppress noise caused by vibration in various industrial equipment and vehicles. To save labor during installation and replacement, sprayable polymer-based sound damping compositions (also known as liquid-applied acoustic damping (LASD) materials) have been developed accordingly. LASD offers higher damping efficiency and a better odor, provides a reduced application amount, and facilitates easy application via an automatically controlled application gun, making it more suitable for automated, lightweight, and environmentally friendly designs.

[0003] LASD compositions can be characterized by either aqueous or non-aqueous systems. Compared to non-aqueous LASD coatings, aqueous systems offer undeniable advantages (such as easier design, a wider damping range, lower VOC emissions, and lower costs). However, their drying performance under bake- or air-drying conditions often results in large blistering and cracking. Adding fiber additives can improve cracking, but this can lead to nozzle clogging, increasing operational difficulty and production costs.

[0004] Therefore, there is a need to develop aqueous LASD compositions that have good acoustic properties, good crack resistance, and good workability, especially at room temperature. Summary of the Invention

[0005] Therefore, the object of the present invention is to overcome the above-mentioned disadvantages by providing a sprayable waterborne LASD composition that has both good crack resistance and good workability.

[0006] An unexpected discovery has been made of waterborne acoustic damping compositions prepared from curable waterborne compositions, comprising: at least one polymer; at least one filler; and a water-soluble cellulose compound or water-soluble starch, which provides both good crack resistance and good workability. At room temperature or after preheating, the waterborne acoustic damping compositions of the present invention are easily applied manually or automatically (especially flat spray) to form a crack-free coating and can improve nozzle clogging issues. Furthermore, some of the waterborne acoustic damping compositions of the present invention do not require additional heating and can be easily integrated into automated spraying production lines at room temperature. In addition, some of the waterborne acoustic damping compositions of the present invention have a high thixotropic index, and the resulting LASD product has a distinctive surface texture. Simultaneously, the LASD composition provides good acoustic damping performance. The waterborne acoustic damping compositions can be applied and cured at room temperature, for example, for automotive industry applications, especially vehicle repair applications.

[0007] According to one aspect, the present invention relates to a sprayable aqueous acoustic damping composition comprising: a) 0.1 to 0.75 parts by weight of a water-soluble cellulose compound or water-soluble starch; b) 10 to 35 parts by weight of a polymer; c) 15 to 30 parts by weight of water; and d) 20 to 45 parts by weight of a filler; wherein the filler comprises an average particle size (d 50 Fillers (i) with a particle size of approximately 7 to 18 μm and an average particle size (d) 50 (ii) Fillers with a particle size of approximately 2 to 5 μm.

[0008] In another aspect, the present invention provides the use of the sprayable aqueous acoustic damping composition according to the invention as a liquid-applied acoustic damping composition.

[0009] In another aspect, the present invention provides an article comprising an aqueous acoustic damping composition on the surface of the article, wherein the aqueous acoustic damping composition is a cured product of the sprayable aqueous acoustic damping composition of the present invention.

[0010] In another aspect, the present invention provides a method for preparing a coated substrate, the method comprising: a) Applying a sprayable aqueous acoustic damping composition as defined in this invention to at least one surface of a substrate by spraying; and b) Curing the composition at 10 to 50°C, preferably at 20 to 30°C.

[0011] In another aspect, the present invention relates to vehicle components obtained by methods as defined herein.

[0012] Other objects and advantages of the present invention will become apparent from the following detailed description and examples of preferred embodiments. Attached Figure Description

[0013] Figure 1 The appearance of the cured compositions of the sprayable waterborne acoustic damping compositions of E1 and CE4 is shown. Detailed Implementation

[0014] The invention will be described in more detail in the following paragraphs. Unless explicitly stated otherwise, each aspect thus described may be combined with one or more other aspects. In particular, any feature indicated as preferred or advantageous may be combined with one or more other features indicated as preferred or advantageous.

[0015] In the context of this invention, unless the context otherwise requires, the terminology used will be interpreted according to the following definitions.

[0016] Unless the context clearly specifies otherwise, the singular forms “a / an” and “the” as used herein include both the singular and plural references. Unless the content clearly specifies otherwise, the term “or” as used in this specification and the appended claims is generally used in its meaning including “and / or”.

[0017] The term “comprising / comprises / comprised of” as used herein is synonymous with “including / includes” or “containing / contains”, and is inclusive or open-ended, and does not exclude additional unlisted members, elements, or method steps.

[0018] The term "polymer" as used in this article is consistent with its common usage in chemistry. A polymer is composed of many repeating subunits. The term "polymer" is used to describe the material obtained from a polymerization reaction.

[0019] The term "acrylic acid" refers to either or both of "acrylic acid" and "methacrylic acid".

[0020] The term "acrylate" refers to either or both of "acrylate" and "methacrylate".

[0021] The term "curing" refers to the hardening process of a material. This term is intended to cover drying the material by evaporating water and a co-solvent from the material, as well as crosslinking of components within the material that have reactive groups (where applicable).

[0022] As used herein, “Mw” refers to weight-average molecular weight and signifies the theoretical value determined by gel permeation chromatography (GPC) relative to linear polystyrene standards from 1.1 M to 580 Da, and can be performed using a Waters 2695 separation module equipped with a Waters 2414 differential refractometer (RI detector). “Mn” is exponential-average molecular weight and also signifies the theoretical value determined by gel permeation chromatography (GPC).

[0023] The glass transition temperature (Tg) used in this paper was determined by differential scanning calorimetry (DSC) according to DIN 53 765 using a ramp rate of 20 K / min and midpoint measurement.

[0024] The "D" used in this article 50 "Particle size" means that the particle size distribution is such that at least 50% by weight of the particles have a diameter smaller than a specified value. Unless otherwise stated, particle size is determined by laser diffraction.

[0025] The thixotropic index (TI) used in this paper is a measure of shear-dependent properties and can be defined as the ratio of viscosity measured at a lower rpm (or low shear rate) to viscosity measured at a higher rpm (or high shear rate).

[0026] The term "water-soluble" means that the relevant components or ingredients of a composition can be dissolved in an aqueous phase at the molecular level.

[0027] Unless otherwise specified, the definition of numerical endpoints includes all numbers and fractions falling into their respective ranges, as well as the listed endpoints.

[0028] Unless otherwise expressly stated, all percentages given herein with respect to compositions or formulations refer to weights relative to the total weight of the respective composition or formulation.

[0029] Unless otherwise defined, all terms used in this disclosure (including technical and scientific terms) have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains. Further guidance includes terminology definitions to better understand the teachings of this invention.

[0030] As previously discussed, embodiments of this disclosure relate to a sprayable aqueous acoustic damping composition comprising: at least one polymer; at least one filler; and at least one water-soluble cellulose compound. The sprayable aqueous acoustic damping composition further comprises an antifoaming agent, and / or a filler, and / or a diluent, and / or a bactericide. Furthermore, the liquid phase of the sprayable aqueous acoustic damping composition comprises water.

[0031] polymer The present invention comprises one or more polymers, particularly “water-based resin” or “water-based polymerresin”.

[0032] As used herein, the terms "water-based polymer," "water-based resin," or "water-based polymer resin" refer to polymeric materials incorporated with water, and / or polymeric materials formed by polymerizing their constituent monomers in an aqueous medium. Water-based resins include, but are not limited to, latexes, emulsions, water-dilutable dispersions, and solutions of polymers or polymer blends in water.

[0033] Suitable water-based resins include any polymers and mixtures thereof prepared from any possible combination of monomers, including but not limited to: acrylic polymer (including copolymer) latexes, styrene-acrylic copolymer latexes, styrene-butadiene copolymer latexes, vinyl acetate latexes (including but not limited to polyvinyl acetate (“PVAc”) latexes and ethylene-vinyl acetate (“EVA”) copolymer latexes), vinyl-acrylic copolymer latexes, etc. Preferred water-based resins include styrene-butadiene latexes, acrylic latexes, acrylate latexes, ethylene-vinyl acetate latexes, and mixtures thereof.

[0034] The acrylic emulsions suitable for use in this invention are in dispersed (emulsified) form and can be selected from any of the acrylic polymer materials conventionally used in aqueous compositions capable of forming vibration and / or damping coatings on a substrate surface. Preferred acrylic polymers include dispersions of acrylate polymers and copolymers (sometimes referred to in the art as acrylic resins), such as copolymers of lower alkyl esters of (meth)acrylate (e.g., n-butyl acrylate) with comonomers (e.g., styrene and / or acrylonitrile). Mixtures of the aforementioned polymers can be used, and combinations are preferred for obtaining the desired properties in the final cured composition. For example, different polymers with different glass transition temperature characteristics can be used in combination. Generally, the glass transition temperatures of the polymers used in this invention typically range from about -10°C to about 40°C, preferably from 0°C to 20°C. However, in one embodiment of the invention, a combination of polymers is used, wherein one polymer has a Tg greater than 0°C (e.g., 5°C to 35°C), while the other polymer is an elastomer and has a Tg less than 0°C (e.g., -10°C to -30°C). Both polymers can be, for example, acrylic resins with different monomer compositions, which are selected to provide the desired Tg characteristics.

[0035] According to the present invention, an acrylic polymer emulsion with a solids content greater than 45% by weight, preferably greater than 50% by weight, is typically obtained. In some embodiments of the present invention, the solids content of the acrylic polymer in the composition is 10 to 40 parts by weight, or 10 to 35 parts by weight, or 20 to 30 parts by weight. Furthermore, an acrylic polymer emulsion having a unimodal particle size distribution should be obtained, characterized by the average particle size (d) of the polymer particles in the aqueous dispersion. 50 The range is 50 to 400 nm, for example, 50 to 200 nm.

[0036] Suitable water-based resins also include styrene-butadiene copolymer latexes with a glass transition temperature of about -20°C to about 50°C. The solids content of styrene-butadiene latex typically ranges from about 45% to about 65%, with about 48% to about 58% being preferred. An exemplary styrene-butadiene latex is GenCal 7463 (a product of Omnova Solutions, Inc., Fairlawn Ohio). GenCal 7463 is a modified styrene / butadiene latex with a solids percentage of about 53%. Another exemplary styrene-butadiene copolymer latex is Styronal ND 656 (a product of BASF Corporation). Styronal ND 656 is a carboxylated styrene / butadiene dispersion with a solids content of about 49% to about 51%, and it forms a film with a glass transition temperature of about 18°C. When a styrene-butadiene water-based resin is used to form a sprayable waterborne acoustic damping composition, the resin is preferably added in an amount (i.e., including both the solid and aqueous phases) of about 15% to about 65% of the total damping composition by weight, wherein an amount ranging from about 15% to about 30% is preferred, and an amount ranging from about 20% to about 25% is particularly preferred.

[0037] Suitable water-based EVA resins include those EVA copolymer latexes having a glass transition temperature of about -20°C to about 50°C. The EVA latex preferably has a solids percentage ranging from about 45% to about 70% by weight, with about 50% to about 65% by weight being preferred. When EVA latex is used to form a sprayable waterborne acoustic damping composition, it is preferably added in an amount ranging from about 10% to about 30% of the total damping composition weight (including both the resin phase and the aqueous phase), with about 15% to about 25% of the EVA latex being preferred.

[0038] filler This invention comprises one or more inorganic fillers in particulate form, which are incorporated into an aqueous composition to provide a matrix for a dry coating, adjust the hardness of the dry coating, improve the sound or vibration damping properties of the dry coating, control bubbling of the dry coating, and / or modify the flammability of the dry coating, and for other purposes. The one or more inorganic fillers may be in any suitable form (e.g., powder, needle-like, flake-like, spherical, plate-like, and other shapes known in the art) and should be insoluble in water. The surface of the filler may be coated with hydrophilic / hydrophobic small molecules / polymers or left unmodified. Examples of suitable inorganic fillers include, but are not limited to: calcium carbonate, alumina, aluminum hydroxide, perlite, barium sulfate, magnesium carbonate, calcium dihydrate, rock wool, asbestos, wollastonite, zeolite, glass or ceramic microspheres, graphite, and the like and mixtures thereof. Preferred inorganic fillers include calcium carbonate, barium sulfate, zinc oxide, alumina, titanium dioxide, aluminum hydroxide, talc, or any combination thereof.

[0039] Inorganic fillers include average particle size (D) 50 Fillers (i) with a particle size of approximately 7 to 18 μm and an average particle size (D) 50 (ii) Fillers with a particle size of approximately 2 to 5 μm.

[0040] The inorganic filler (i) is characterized by an average particle size (D) of about 7 to 18 μm, preferably 7 to 15 μm, or 10 to 12 μm. 50 The amount of inorganic filler (i) in the composition, particularly the particulate filler of the composition, is at least 15 parts by weight, or at least 18 parts by weight, or at least 20 parts by weight, or at least 22 parts by weight, or at least 25 parts by weight, or at least 30 parts by weight.

[0041] Inorganic fillers (ii) are characterized by an average particle size (D) of about 2 to 5 μm, or 2.5 to 5 μm, or 3 to 5 μm. 50 The amount of inorganic filler (ii) in the composition, particularly the particulate filler of the composition, is at least 3 parts by weight, or at least 5 parts by weight, or at least 10 parts by weight, or at least 12 parts by weight, or at least 15 parts by weight.

[0042] The weight ratio of packing (i) to packing (ii) is 1.9:1 to 4:1, or 2.0:1 to 3.5:1, or 2.0:1 to 3.2:1, or 2.0:1 to 2.9:1.

[0043] Water-soluble cellulose compounds This invention comprises a water-soluble cellulose compound or a water-soluble starch, wherein the water-soluble cellulose compound includes water-soluble cellulose derivatives. Water-soluble cellulose derivatives include, but are not limited to, water-soluble cellulose ethers and water-soluble cellulose salts. Unexpectedly, compositions of this invention using water-soluble cellulose ethers and / or water-soluble cellulose salts along with fillers (i) and (ii) exhibit good crack resistance and a high thixotropic index.

[0044] Some water-soluble polysaccharides (such as xanthan gum) are not suitable for this invention. Some insoluble polysaccharides (such as insoluble starch) are also not suitable for this invention.

[0045] In some embodiments, water-soluble starch, water-soluble cellulose salt, or water-soluble cellulose ether is provided as a dry powder. Suitable water-soluble cellulose ether powder, cellulose salt powder, and water-soluble starch powder include, but are not limited to, Natrosol 250 HHR and Natrosol 250 LR supplied by Ashland Inc, and CMC 75 A Powder supplied by Mikro-Technik GmbH & Co. KG.

[0046] Without being bound by any theory, it is believed that the addition of water-soluble starch, and / or cellulose salts, and / or cellulose ethers to the damping compositions described herein creates hydrogen bonds between the resin, filler, and water, which prevents phase separation during heating or drying processes and improves cracking after drying. In some exemplary embodiments, the amount of water-soluble starch, and / or cellulose salts, and / or cellulose ethers added to the damping composition is from about 0.1 parts by weight to about 0.75 parts by weight in the total damping composition. Preferably, it is from 0.2 parts by weight to about 0.5 parts by weight, or from 0.25 parts by weight to about 0.4 parts by weight. In some embodiments, the amount of water-soluble cellulose ethers, and / or cellulose salts added to the damping composition is at most 0.9 parts by weight, or at most 0.8 parts by weight, or at most 0.75 parts by weight, or at most 0.6 parts by weight, or at most 0.5 parts by weight. Excessive amounts of water-soluble cellulose ethers and / or cellulose salts (e.g., more than 0.9 parts by weight, or more than 1.0 parts by weight, or more than 1.2 parts by weight, or more than 1.5 parts by weight) can cause gelation or clogging of the nozzle by compositions that are too thick (too viscous) for flat spraying.

[0047] Other compounds If desired, the sprayable aqueous acoustic damping composition may contain various additives, such as defoamers, fillers, diluents, bactericides, and pigments (dyes), without hindering the purpose of the invention. By adding such fillers / additives, physical properties (such as rheological properties, viscosity, flow rate, antibacterial properties, etc.) can be adjusted to desired values.

[0048] In some embodiments of the present invention, the composition further comprises 0.02 to 2 parts by weight of an antifoaming agent.

[0049] In some embodiments of the invention, the composition further comprises 5 to 11 parts by weight, or 5 to 10 parts by weight, of mica.

[0050] In some embodiments of the present invention, the composition does not contain fumed silica as a thixotropic agent.

[0051] The sprayable aqueous acoustic damping composition of the present invention contains water as a solvent to dissolve all components, thereby forming a sealing solution. In some embodiments of the invention, deionized water is preferably used as the solvent. In some embodiments of the invention, the water content in the composition is 20 to 30 parts by weight.

[0052] Preparation method of sprayable waterborne acoustic damping composition A sprayable, water-based acoustic damping composition is formulated by simply mixing various components.

[0053] In some embodiments, the sprayable aqueous acoustic damping composition comprises 15.0 to 30.0 parts by weight of water as a liquid phase.

[0054] Without particularly limiting the amount of water contained in the aqueous composition, it is preferred that the composition contains 15 to 30% by weight, preferably 20 to 30% by weight, of water based on the weight of the composition.

[0055] Application method of sprayable water-based acoustic damping composition According to the broadest aspect of the invention, the above composition is applied to a substrate and then cured in situ.

[0056] The invention is not intended to limit the substrates to which the compositions can be applied. In applications to vehicle panels, exemplary substrates may be metallic, polymeric, or combinations thereof. However, specific references may be made to: ferrous metals, such as iron, steel, and their alloys; non-ferrous metals, such as aluminum, zinc, and their alloys; and combinations thereof. In illustrative embodiments, the substrate may be formed of: cold-rolled steel; electro-galvanized steel, such as hot-dip galvanized steel or electro-galvanized iron-zinc steel; or aluminum.

[0057] Pretreatment of the relevant surfaces to remove foreign matter is generally recommended before applying the composition; if applicable, this step can promote the subsequent adhesion of the composition to them. Such treatments are known in the art and can be performed in a single-stage or multi-stage manner, consisting of, for example, one or more of the following: immersion in an aqueous alkaline degreasing bath; treatment with an aqueous cleaning emulsion; treatment with a cleaning solvent (such as carbon tetrachloride or trichloroethylene); and rinsing with water, preferably with deionized or demineralized water. In those cases where an aqueous alkaline degreasing bath is used, any degreasing agent remaining on the surface should be expected to be removed by rinsing the substrate surface with deionized or demineralized water.

[0058] The composition is then applied to a preferably pretreated, optionally primer-coated surface of the substrate by spraying (including but not limited to: air atomization spraying, air-assisted spraying, airless spraying, and high-volume low-pressure spraying).

[0059] The thickness of the coating applied in this invention can be adjusted so that the final cured coating effectively suppresses noise and vibration transmission to the desired level. In many cases, the composition is applied as a wet film thickness of 1 to 5 mm. Applying thinner layers within this range is more cost-effective and offers the possibility of reducing harmful thick cured areas. However, strict control must be exercised when applying thinner coatings or layers to avoid the formation of discontinuous cured films.

[0060] The curing of the compositions of the present invention is generally carried out at room temperature or at a temperature in the range of 10°C to 50°C, preferably 20°C to 30°C. The appropriate temperature depends on the specific compound present and the desired curing rate, and can be determined by those skilled in the art in each case using simple preliminary tests (if necessary).

[0061] It should be understood that all embodiments of the methods disclosed herein are similarly applicable to the disclosed dispersions, compositions, and uses, and vice versa.

[0062] List of Implementation Plans 1. A sprayable waterborne acoustic damping composition, said sprayable waterborne acoustic damping composition comprising: a) 0.1 to 0.75 parts by weight of a water-soluble cellulose compound or water-soluble starch; b) 10 to 35 parts by weight of the polymer; c) 15 to 30 parts by weight of water; d) 20 to 45 parts by weight of filler; The filler includes an average particle size (d) 50 Fillers (i) with a particle size of approximately 7 to 18 μm and an average particle size (d) 50 (ii) Fillers with a particle size of approximately 2 to 5 μm.

[0063] 2. The composition according to embodiment 1, wherein the water-soluble cellulose compound comprises at least one water-soluble cellulose derivative selected from cellulose ethers, cellulose salts, or combinations thereof.

[0064] 3. The composition according to any one of the foregoing embodiments, wherein the water-soluble cellulose compound or the water-soluble starch in the composition is present in an amount of 0.2 to 0.5 parts by weight.

[0065] 4. The composition according to any one of the foregoing embodiments, wherein the polymer comprises one or more selected from the following: acrylic polymers (including copolymers), styrene-acrylic copolymers, styrene-butadiene copolymers, vinyl acetate (including but not limited to polyvinyl acetate (“PVAc”) and ethylene-vinyl acetate (“EVA”) copolymers), vinyl-acrylic copolymers, etc.

[0066] 5. The composition according to any one of the foregoing embodiments, wherein the polymer comprises styrene-butadiene polymers, acrylic polymers, acrylate polymers, ethylene-vinyl acetate polymers, and mixtures thereof.

[0067] 6. The composition according to any one of the foregoing embodiments, wherein the polymer content in the composition is 20 to 30 parts by weight.

[0068] 7. The composition according to any one of the foregoing embodiments, wherein the filler is selected from calcium carbonate, barium sulfate, zinc oxide, aluminum oxide, titanium dioxide, aluminum hydroxide, talc, or any combination thereof.

[0069] 8. The composition according to any one of the foregoing embodiments, wherein the weight ratio of the filler (i) to the filler (ii) is 1.9:1 to 4:1, preferably 2:1 to 2.9:1.

[0070] 9. The composition according to any one of the foregoing embodiments, wherein the composition further comprises 0.02 to 2 parts by weight of an antifoaming agent.

[0071] 10. The composition according to any one of the foregoing embodiments, wherein the composition further comprises 5 to 11 parts by weight of mica.

[0072] 11. The composition according to any one of the foregoing embodiments, wherein the water content in the composition is 20 to 30 parts by weight.

[0073] 12. The composition according to any one of the foregoing embodiments, wherein the composition does not contain fumed silica as a thixotropic agent.

[0074] 13. Use of the sprayable waterborne acoustic damping composition as defined in any one of embodiments 1-12 as a liquid-applied acoustic damping composition.

[0075] 14. An article comprising an aqueous acoustic damping composition on the surface of the article, wherein the aqueous acoustic damping composition is a cured product of a sprayable aqueous acoustic damping composition according to any one of embodiments 1-12.

[0076] 15. A method for preparing a coated substrate, the method comprising: c) Applying a sprayable aqueous acoustic damping composition as defined in any one of embodiments 1-12 to at least one surface of a substrate by spraying; and d) Curing the composition at 10 to 50°C, preferably at 20 to 30°C.

[0077] 16. Vehicle components obtained by means of the method defined in implementation scheme 15.

[0078] Example: The invention will be further described and illustrated in detail below with reference to the embodiments. These embodiments are intended to help those skilled in the art better understand and practice the invention, but are not intended to limit the scope of the invention. Unless otherwise stated, all figures in the embodiments are based on weight.

[0079] raw material

[0080] All raw materials are used directly without any special processing.

[0081] Example 1 <Preparation of Sprayable Waterborne Sound Damping Compositions> To prepare the sprayable waterborne acoustic damping composition E1, a polymer emulsion, dispersant, bactericide, filler, Natrosol 250 HHR, and CMC 75 A Powder were added to a container and mixed using a PC laboratory mixer at 200–500 rpm until all materials were saturated. Then, the mixture was mixed for 40 minutes at 35°C and 600–900 rpm using a PC laboratory mixer. Subsequently, Graphite K 500 was added and mixed using a high-speed mixer at 200–500 rpm until saturated. This was then repeated for 40 minutes at 35°C and 600–900 rpm. Finally, the mixture was mixed for 60 minutes under a vacuum of 40 mbar at 600–900 rpm. The particle size was then checked to complete the batch.

[0082] <Curing of Aqueous Sound Damping Compositions> The composition is applied to the substrate by spraying with a Power Line II gun and a widespread nozzle. The thickness is controlled to be from about 1 mm to about 5 mm (e.g., from about 2 mm to about 4 mm). After application to the substrate, the composition is allowed to cure at room temperature (25°C) for at least about 10 minutes, more typically about 6 hours to about 12 hours.

[0083] Examples 2 to 11, and CE1 to CE9 Sprayable aqueous acoustic damping compositions E2 to E11 and CE1 to CE7 were prepared according to Example 1. The aqueous acoustic damping compositions E2 to E11 and CE1 to CE7 were cured according to Example 1. Further details are listed in the results section below.

[0084] Test methods Viscosity When measuring the viscosity of the prepared sprayable waterborne acoustic damping composition, an Anton Paar MCR 302 rheometer was used, with a 25 mm diameter parallel disk rotor, an oscillation frequency of 1 Hz, an amplitude of 0.3%, a rheometer disk temperature of 25°C, and a 1 s... -1 The dynamic viscosity was measured by the shear rate, and the viscosity was recorded as 1 s. -1 The viscosity at that point.

[0085] Using an Anton Paar MCR 302 rheometer at 25°C with a 0.5 mm gap and 100 s... -1 The shear rate was measured for "high shear viscosity," and the viscosity was recorded as 100 s⁻¹. -1 The viscosity at that point.

[0086] Following the high shear test, an Anton Paar MCR 302 rheometer was used at 25°C with a 0.5 mm gap and a 1s interval. -1 The shear rate was measured for "low shear viscosity," and the viscosity was recorded as 1 s. -1 Viscosity at the following levels (after high shear test).

[0087] The thixotropic index (TI) is a measure of shear-dependent properties and can be defined as the ratio of viscosity measured at a lower shear rate to viscosity measured at a higher shear rate. The TI used in this paper is 1 s⁻¹. -1 Viscosity at 100 s (after high shear test) -1 The ratio of the viscosity at different levels.

[0088] Phase separation The composition is filled downward into an aluminum cartridge, and the overall package consists of a cartridge, a stopper, and a cap. The cartridge is then used to perform a phase separation test by method a).

[0089] a) Store at room temperature (ambient temperature 5 to 35°C) for at least 3 months, then quickly check for water condensation in the space between the stopper and the cap.

[0090] Acoustic damping The curing of the sound insulation composition used for damping testing may include the following steps: a) Expose the sound insulation composition to indoor conditions for 1 to 4 hours; b) Heating the sound insulation composition at a temperature range of 40 to 80°C for 2 to 6 hours; and c) Cool the sound insulation composition and allow the sound insulation material to cure at room temperature for 5 to 10 days.

[0091] The loss factor of the cured product of the sound insulation composition in this invention can be measured according to GB / T 16406.

[0092] Appearance (crack inspection) Inspect the appearance of the cured sample.

[0093] Record the appearance test results and classify them as follows: - Yes: Crack - No: No cracks.

[0094] result Table 1

[0095] Table 1 shows the composition of sprayable waterborne acoustic damping compositions E1 to E11.

[0096] Table 2.

[0097] Table 2 shows the test results for sprayable waterborne acoustic damping compositions E1 to E11.

[0098] Table 3.

[0099] Table 3 shows the composition of the comparative sprayable waterborne acoustic damping compositions CE1 to CE7.

[0100] Table 4.

[0101] Table 4 shows the test results for the comparative sprayable waterborne acoustic damping compositions CE1 to CE7.

[0102] It can be seen that the sprayable waterborne acoustic damping compositions E1 to E11 provide good stability without phase separation. Furthermore, the cured products of the E1 to E11 sprayable waterborne acoustic damping compositions offer good acoustic damping performance (loss factor greater than 0.1 at 20°C and 200 Hz, with a damping film thickness of 2.3 mm), possess a unique surface texture, and good crack resistance. The E2 sprayable waterborne acoustic damping composition exhibits a high 100 s... -1 Due to the high mica content in the composition, the viscosity is low, and the composition requires an additional 5-10 minutes of heating at room temperature before spraying.

[0103] Sprayable waterborne acoustic damping compositions of CE1 through CE3 exhibit surface cracking. CE1 does not contain water-soluble cellulose compounds or fillers (i). CE2 contains D 50 The composition contains a 20 μm filler and a water-soluble cellulose compound. CE3 contains a water-soluble cellulose compound but no filler (i). In the absence of the water-soluble cellulose compound, filler (i), and filler (ii), the composition exhibits poor crack resistance.

[0104] CE4 contains filler (i), filler (ii), and fumed silica, but does not contain water-soluble cellulose compounds. Phase separation occurred in the composition of CE3. The cured LASD product does not have a distinctive surface texture.

[0105] Figure 1 The appearance of the cured compositions of the sprayable waterborne acoustic damping compositions E1 and CE4 is shown. It can be seen that the waterborne acoustic damping composition of CE4 has a TI value of less than 10.0, and the resulting LASD product has a smooth surface. However, the waterborne acoustic damping composition of E1 has a high thixotropic index (greater than 15), and the resulting LASD product has a distinctive surface texture.

[0106] CE5 contains another water-soluble polysaccharide compound, xanthan gum. A comparison between E5 and CE5 shows that the cured composition containing xanthan gum is brittle and exhibits surface cracks.

[0107] The composition of CE7 contains an excessive amount of water-soluble cellulose compound, and the viscosity of the composition is too high to work. It can be observed that the suitable amount of cellulose compound in the total composition is less than 1.0 part by weight.

Claims

1. A sprayable waterborne acoustic damping composition, said sprayable waterborne acoustic damping composition comprising: a) 0.1 to 0.75 parts by weight of a water-soluble cellulose compound or water-soluble starch; b) 10 to 35 parts by weight of the polymer; c) 15 to 30 parts by weight of water; d) 20 to 45 parts by weight of filler; The filler includes an average particle size (d) 50 Fillers (i) with a particle size of approximately 7 to 18 μm and an average particle size (d) 50 (ii) Fillers with a particle size of approximately 2 to 5 μm.

2. The composition according to claim 1, wherein the water-soluble cellulose compound comprises at least one water-soluble cellulose derivative selected from cellulose ethers, cellulose salts, or combinations thereof.

3. The composition according to claim 1, wherein the content of the water-soluble cellulose compound or the water-soluble starch in the composition is 0.2 to 0.5 parts by weight.

4. The composition of claim 1, wherein the polymer comprises one or more selected from the group consisting of acrylic polymers (including copolymers), styrene-acrylic copolymers, styrene-butadiene copolymers, vinyl acetate (including but not limited to polyvinyl acetate ("PVAc") and ethylene-vinyl acetate ("EVA") copolymers), vinyl-acrylic copolymers, and the like.

5. The composition according to claim 1, wherein the polymer comprises styrene-butadiene polymers, acrylic polymers, acrylate polymers, ethylene-vinyl acetate polymers, and mixtures thereof.

6. The composition according to claim 1, wherein the polymer content in the composition is 20 to 30 parts by weight.

7. The composition according to claim 1, wherein the filler is selected from calcium carbonate, barium sulfate, zinc oxide, aluminum oxide, titanium dioxide, aluminum hydroxide, talc, or any combination thereof.

8. The composition according to claim 1, wherein the weight ratio of the filler (i) to the filler (ii) is 1.9:1 to 4:1, preferably 2:1 to 2.9:

1.

9. The composition according to claim 1, wherein the composition further comprises 0.02 to 2 parts by weight of an antifoaming agent.

10. The composition according to claim 1, wherein the composition further comprises 5 to 11 parts by weight of mica.

11. The composition according to claim 1, wherein the water content in the composition is 20 to 30 parts by weight.

12. The composition according to claim 1, wherein the composition does not contain fumed silica as a thixotropic agent.

13. Use of the sprayable aqueous acoustic damping composition as defined in any one of claims 1-12 as a liquid-applied acoustic damping composition.

14. An article comprising an aqueous acoustic damping composition on the surface of the article, wherein the aqueous acoustic damping composition is a cured product of a sprayable aqueous acoustic damping composition according to any one of claims 1-12.

15. A method for preparing a coated substrate, the method comprising: a) Applying a sprayable aqueous acoustic damping composition as defined in any one of claims 1-12 to at least one surface of a substrate by spraying; as well as b) Curing the composition at 10 to 50°C, preferably at 20 to 30°C.

16. A vehicle component obtained by the method defined in claim 15.

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