Emulsions for wide temperature range sound attenuation properties

Abstract

The present disclosure provides a polymer emulsion that provides a sound attenuation loss factor of at least 0.1 at 200 Hz within a temperature of 0 DEG C to 60 DEG C.

Description

Technical Field

[0001] The present disclosure relates generally to the field of polymers, particularly liquid applied sound dampening compositions, and to methods of making them and their use in sound dampening applications over a wide temperature range. Background Art

[0002] To reduce the noise generated by vibrations in vehicles, appliances, and machinery, damping materials are applied to the vibrating areas to effectively dissipate the vibration energy. Applying mastic or asphalt pads to the vibrating surface can dissipate some of the vibration energy, but this method is labor intensive and expensive in application because complex shapes must be produced to cover critical areas. Epoxy or PVC-based vibration damping coatings are also used, but these are expensive and contain volatile organic compounds that can create hazards when the coating is applied. None of these damping technologies provide a cost-effective and low-VOC solution for effective damping of vehicles, appliances, and machinery.

[0003] Formulations containing aqueous emulsions of acrylic polymers are known in the art to be effective in vibration damping. These formulations are water-based and do not contain any harmful volatile organic chemicals. They are viscous materials that can be applied by a variety of techniques, but are most commonly sprayed onto the substrate with a robot, which minimizes the labor of application and allows the material to be applied only in areas where damping is required, and in a customized thickness to achieve the desired level of vibration damping.

[0004] However, these emulsions generally provide effective damping only within a narrow temperature range. There is a need in the industry for improved aqueous emulsions to achieve better damping performance and better formulation properties. Summary of the invention

[0005] Disclosed herein is an aqueous dispersion of an acrylic polymer comprising particles of an acrylic polymer dispersed in an aqueous medium, wherein the aqueous polymer emulsion provides sound attenuation over a wide temperature range. In another aspect, provided herein is a method for preparing an aqueous dispersion of an acrylic polymer described herein. In some embodiments, the aqueous polymer dispersion is prepared using a free radical emulsion polymerization process. In some embodiments, the free radical emulsion polymerization process is carried out in a dual feed reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0007] Figure 1 A schematic diagram of a dual feed polymerization reactor for synthesizing the acrylic emulsions of the present disclosure is provided.

[0008] Figure 2A computer generated graph plotting the composite loss factor versus temperature is provided. This graph demonstrates the desirable acoustic performance of acrylic emulsions over a wide temperature range.

[0009] Figure 3 Experimental data for the emulsions of the present disclosure are provided on a graph of composite loss factor versus temperature. DETAILED DESCRIPTION

[0010] As used herein, the term "comprising" and its variants are used synonymously with the term "including" and its variants, and are open, non-limiting terms. Although the terms "comprising" and "including" have been used herein to describe various embodiments, the terms "consisting essentially of" and "consisting of" can be used in place of "comprising" and "including" to provide more specific embodiments and are also disclosed. The singular forms "a / kind", "the" and "the" used in the present disclosure and the appended claims include plural referents unless the context clearly indicates otherwise. The percentage ranges and other ranges disclosed herein include the endpoints of the disclosed ranges as well as any integers provided in the ranges.

[0011] I. Noise-absorbing emulsion

[0012] As described above, the present disclosure relates to emulsions for sound damping. More specifically, the present disclosure describes aqueous polymer emulsions in liquid applied sound damping (LASD) formulations to produce highly effective damping materials for use in vehicles, appliances, and machinery to mitigate the adverse effects of unwanted vibrations. Also disclosed are methods of producing highly effective aqueous polymer emulsions that can be adjusted to provide effective damping over a wide temperature range. Emulsions as described herein may also be referred to as "damping formulations" or "damping compositions."

[0013] Typical formulations of LASD materials may include one or more of an aqueous polymer emulsion, an inorganic filler, an emulsifier, and a viscosity modifier. The polymer from the emulsion provides the viscoelastic properties of the final dried product. A proper balance of viscous and elastic properties at the desired temperature can provide effective damping properties. Inorganic fillers, which may be one or more of calcium carbonate, barium sulfate, and mica, can provide mass and hardness to the dried LASD material. Good interaction between the polymer and the filler can improve the viscoelastic balance and enhance the damping properties. Emulsifiers can be used to help disperse the inorganic filler in the formulation and allow the highly filled formulation to remain fluid, while thickeners can be added to achieve the correct viscosity profile so that the material is fluid enough to be pumped and sprayed, but thick enough so that it does not sag and flow when applied. Other ingredients may also be added to harden or soften the product. Colorants may also be added. Defoamers may also be added to help eliminate trapped bubbles, and other additives may be included to improve drying / baking properties.

[0014] Generally, the glass transition temperature (Tg) and molecular weight (Mw) define the silencing capability of a liquid-applied silencing coating. Since the polymer Tg affects the peak silencing temperature, the widening of the Tg region can help to widen the temperature of the silencing region. The silencing peak can be maximized by adjusting the molecular weight of the polymer. Low Mw polymers are generally beneficial for improving the composite loss factor at a specific temperature. High Mw polymers generally have a higher degree of entanglement, which means that the material can be stretched far before breaking. Therefore, the balance of the polymer's Mn, Mw, Mz and polydispersity index can widen the silencing temperature range and also maximize the composite loss factor peak.

[0015] Emulsions can be formed by emulsion polymerization, which relies on the use of small molecule surfactants containing polar / hydrophilic groups and non-polar / hydrophobic groups. The amphiphilic nature of these materials allows them to effectively stabilize heterogeneous solutions (even polymer particles in water).

[0016] The emulsion can utilize a resin carrier.

[0017] The emulsion may comprise one or more polymers. For example, the emulsion of the present disclosure may comprise two, three, four or any suitable number of polymers. In embodiments using a variety of polymers, each polymer may have different properties, such as glass transition temperature (Tg). A variety of polymers with different Tg values ​​may be combined to form a damping emulsion that provides a wide damping distribution within a certain temperature range.

[0018] In embodiments using multiple polymers, the polymers may be present in any suitable ratio. For example, the damping formulation may include four polymers in a weight ratio of W:X:Y:Z. W, X, Y, and Z may each independently be 0.5, 0.6, 0.7, 0.75, 0.8, 0.9, 1, 1.1, 1.2, 1.25, 1.3, 1.4, 1.5, 1.6, 1.7, 1.75, 1.8, 1.9, 2, or any range including any of these values ​​as endpoints. For example, W, X, Y, and Z may each independently be 0.5 to 2, 0.5 to 1.5, 0.75 to 1.5, 0.75 to 1.25, 0.75 to 1.2, 0.9 to 1.1, or any subrange within these ranges. The weight ratio of the polymer may be changed to adjust the damping distribution of the damping formulation.

[0019] Emulsion can include low molecular weight copolymer.For example, the polymer in emulsion can have the number average molecular weight (Mn) of about 1,000g / mol to about 75,000g / mol.This can include about 1,000g / mol to about 65,000g / mol or about 1,000g / mol to about 50,000g / mol or about 1,000g / mol to about 30,000g / mol or about 1,000g / mol to about 20,000g / mol or about 1,000g / mol to about 15,000g / mol or about 1,000g / mol to about 10,000g / mol number average molecular weight.In some embodiments, low molecular weight copolymer can have the weight average molecular weight of about 1,500g / mol to about 35,000g / mol.This includes the weight average molecular weight of about 8,000g / mol to about 12,000g / mol.

[0020] The polymer of the formulation of the present invention may have a molecular weight (Mw) of 50,000 to 220,000. This may include molecular weights of 60,000 to 210,000, 70,000 to 200,000, 80,000 to 190,000, 90,000 to 180,000, 100,000 to 170,000, 110,000 to 160,000, 120,000 to 150,000, 130,000 to 140,000, or any sub-range of molecular weights within any of these ranges.

[0021] The polymer of the formulation of the present invention may have a Z average molecular weight (Mz) of 275,000 to 700,000. This may include a Z average molecular weight of 275,000 to 600,000, 275,000 to 500,000, 275,000 to 400,000, 275,000 to 300,000, or any sub-range within any of these ranges.

[0022] The polymers of the formulations of the present invention may have a low polydispersity index. This includes polydispersity indices of 10 or less, 8 or less, 6 or less, 4 or less, or 2 or less.

[0023] In some embodiments, the low molecular weight copolymer may be a copolymer of acrylic acid and styrene.

[0024] Suitable monomers for preparing the emulsion include, but are not limited to, acrylic acid, methacrylic acid, styrene, alpha-methylstyrene, hydroxyethyl methacrylate, and esters of acrylic acid and methacrylic acid.

[0025] In some embodiments, the low molecular weight copolymer can be a carboxylic acid functional resin. In some embodiments, the carboxylic acid functional resin can be an alkali soluble resin. In other words, the carboxylic acid functional resin can react with an alkaline material to form an ionic salt at the carboxylate group of the polymer, thereby enhancing the water solubility of the resin. Suitable monomers for preparing carboxylic acid functional resins and low molecular weight copolymers include monomers such as: acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, acrylic anhydride, methacrylic anhydride, itaconic anhydride, maleic anhydride, fumaric anhydride, crotonic anhydride, styrene, methyl styrene, α-methyl styrene, ethyl styrene, isopropyl styrene, tert-butyl styrene, ethyl methacrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, ethyl acrylate, vinyl acetate, methyl acrylate, open-chain conjugated diene, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, hydroxymethyl acrylamide, glycidyl acrylate, glycidyl methacrylate, vinyl ester, vinyl chloride or any mixture of two or more such monomers. In some embodiments, the carboxylic acid functional carrier resin includes one or more of the following polymerized monomers: ethyl methacrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, ethyl acrylate, vinyl acetate, methyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, glycidyl methacrylate, or a mixture of any two or more such monomers. In one embodiment, the carboxylic acid functional resin includes one or more of the following polymerized monomers: acrylic acid, ethyl methacrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, ethyl acrylate, vinyl acetate, methyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, glycidyl methacrylate, styrene, methyl styrene, α-methyl styrene, diacetone acrylamide, ureido methacrylate, or a mixture of any two or more such monomers. In some embodiments, the carboxylic acid functional resin may include a copolymer comprising two or more of styrene, methyl methacrylate, and acrylic acid. In some embodiments, the carboxylic acid functional carrier resin may include a copolymer of acrylic acid and styrene.

[0026] The one or more polymers used in the emulsion may have a glass transition temperature (Tg) of the individual polymers from -60°C to 130°C, or any subrange or value within the range. For example, any given polymer in the emulsion may have a glass transition temperature (Tg) of from -60°C to 100°C, from -60°C to 75°C, from -60°C to 50°C, from -15°C to 50°C, from -15°C to 45°C, from -15°C to 40°C, from -15°C to 35°C, from -15°C to 30°C, from -15°C to 25°C, from -15°C to 20°C, from -15°C to 15°C, from -15°C to 1 .... ℃ to 0℃, 0℃ to 50℃, 0℃ to 45℃, 0℃ to 40℃, 0℃ to 35℃, 0℃ to 30℃, 0℃ to 20℃, 0℃ to 15℃, 0℃ to 10℃, 10℃ to 50℃, 10℃ to 45℃, 10℃ to 40℃, 10℃ to 35℃, 10℃ to 30℃, 10℃ to 25℃, 10℃ to 20℃, or any range of Tg including any two of these values ​​as endpoints.

[0027] The emulsion or combination of polymers may have a glass transition temperature (Tg) of the individual polymers from -60°C to 130°C, or any subrange or value within the range. For example, any given polymer within the emulsion may have a glass transition temperature (Tg) of -60°C to 100°C, -60°C to 75°C, -60°C to 50°C, -15°C to 50°C, -15°C to 45°C, -15°C to 40°C, -15°C to 35°C, -15°C to 30°C, -15°C to 25°C, -15°C to 20°C, -15°C to 1 ...50°C, -15°C to 55°C, -15°C to 60°C, -15°C to 75°C, -15°C to 80°C, -15°C to 90°C, -15°C to 100°C, -15°C to 150°C, -15°C to 150°C, -15°C to 150°C, -15°C to 150°C. ℃ to 0℃, 0℃ to 50℃, 0℃ to 45℃, 0℃ to 40℃, 0℃ to 35℃, 0℃ to 30℃, 0℃ to 20℃, 0℃ to 15℃, 0℃ to 10℃, 10℃ to 50℃, 10℃ to 45℃, 10℃ to 40℃, 10℃ to 35℃, 10℃ to 30℃, 10℃ to 25℃, 10℃ to 20℃, or any range of Tg including any two of these values ​​as endpoints.

[0028] The polymer can be formed from emulsion polymerizable monomers. Emulsion polymerizable monomers are known in the art. See, for example, U.S. Patent Nos. 4,820,762, 7,253,218, 7,893,149; and U.S. Patent Publication No. 2015 / 0166803. The emulsion polymerizable monomers can include ethylenically unsaturated monomers. In some embodiments, the emulsion polymerizable monomers can include at least one ethylenically unsaturated nonionic monomer. "Nonionic monomer" herein means that the comonomer residue does not carry an ionic charge between pH 1 and 14. Suitable ethylenically unsaturated nonionic monomers include, but are not limited to, (meth)acrylate monomers including methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, lauryl acrylate, methyl methacrylate, butyl methacrylate, isodecyl methacrylate, lauryl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate; (meth)acrylonitrile; (meth)acrylamide; urea-functional monomers; monomers with acetoacetate functionality; styrene and substituted styrenes; butadiene; ethylene, propylene, α-olefins such as 1-decene; vinyl acetate, vinyl butyrate and other vinyl esters; and vinyl monomers such as vinyl chloride and vinylidene chloride.

[0029] The emulsion polymerizable monomers may include acrylate monomers, methacrylate monomers, styrene monomers, or mixtures of any two or more thereof. In some embodiments, the emulsion polymerizable monomers do not include styrene monomers.

[0030] In some embodiments, at least one emulsion polymerizable monomer may be a C1-C4 acrylate, a C1-C4 (meth)acrylate, or a mixture of any two or more thereof. In some embodiments, the emulsion polymerizable monomer may be n-butyl acrylate, 2-ethylhexyl acrylate, methyl acrylate, methyl methacrylate, styrene, ethyl acrylate, or a mixture of any two or more thereof.

[0031] In some embodiments, the emulsion polymerizable polymer may include one or more ketone functional monomers. Examples of ketone functional monomers include diacetone acrylamide, diacetone methacrylamide, diacetone acrylate, diacetone methacrylate, acetoacetoxymethyl (meth)acrylate, 2-(acetoacetoxy)ethyl (meth)acrylate, 2-acetoacetoxypropyl (meth)acrylate, butanediol-1,4-acrylate-acetoacetate, vinyl methyl ketone, vinyl ethyl ketone and vinyl isobutyl ketone, allyl acetoacetate, vinyl acetoacetate or vinyl acetoacetamide. In one embodiment, the emulsion polymerizable polymer includes repeating units derived from diacetone acrylamide.

[0032] The emulsion may be formed by an emulsion polymerization reaction, which may involve at least one emulsion polymerizable monomer, a low molecular weight copolymer, and other ingredients and / or reagents, such as an initiator. In some embodiments, the emulsion polymerization is conducted in a dual feed reactor.

[0033] The initiator can be a water-soluble compound that is easy to mix and blend with the emulsion. Non-limiting examples of water-soluble initiators for emulsion polymerization include ammonium salts and alkali metal salts of peroxodisulfuric acid (e.g., sodium peroxodisulfate), hydrogen peroxide, or an organic peroxide, for example, tert-butyl peroxide. The initiator can be a thermal initiator. Suitable initiators include, but are not limited to, 2,2'-azobis(2-methylpropionamidine) dihydrochloride, ammonium persulfate, sodium persulfate, and potassium persulfate. Reduction-oxidation (redox) initiator systems are also suitable. Redox initiator systems consist of at least one, usually inorganic, reducing agent and an organic or inorganic oxidizing agent. The oxidizing component includes, for example, the emulsion polymerization initiators identified above. The reducing component includes, for example, alkali metal salts of sulfurous acid, such as, for example, sodium sulfite, sodium bisulfite; alkali metal salts of pyrosulfite, such as sodium pyrosulfite; addition compounds of bisulfite with fatty aldehydes and ketones, such as acetone bisulfite; or reducing agents, such as hydroxymethanesulfinic acid and its salts, or ascorbic acid. Redox initiator systems can be used together with soluble metal compounds, and their metal components can exist in multiple valence states. Typical redox initiator systems are, for example, ascorbic acid / ferrous sulfate (II) / sodium peroxodisulfate, tert-butyl peroxide / sodium pyrosulfite, tert-butyl peroxide / sodium hydroxymethanesulfinate. Individual components, such as reducing components, can also be mixtures, an example of which is a mixture of the sodium salt of hydroxymethanesulfinic acid and sodium pyrosulfite. The compound is usually used in the form of an aqueous solution, wherein the lower concentration is determined by the amount of water acceptable in the dispersion, and the higher concentration is determined by the solubility of the corresponding compound in water. Generally speaking, based on the solution, the concentration is 0.1% to 30% by weight, preferably 0.5% to 20% by weight, and more preferably 1.0% to 10% by weight. Based on the monomer to be polymerized, the amount of the initiator is usually 0.1% to 10% by weight, preferably 0.5% to 5% by weight. Two or more different initiators can also be used in emulsion polymerization.

[0034] In some embodiments, the initiator may be ammonium persulfate and the oxidant may be tert-butyl peroxide. In this case, the weight ratio between ammonium persulfate and tert-butyl peroxide may be in the range of 40:1 to 2:1 or 30:1 to 4:1, or any sub-range or value within these ranges.

[0035] In some embodiments, the emulsion comprises one or more chain transfer agents to control molecular weight, branching and / or gel formation. Exemplary chain transfer agents include, but are not limited to, isooctyl mercaptopropionate (IOMPA), butyl mercaptopropionate, 2-ethylhexyl mercaptopropionate, tert-dodecyl mercaptan, and thioglycerol.

[0036] Generally, the amount of chain transfer agent employed may vary from 0.05% to 1% by weight, based on the total amount of monomers to be polymerized.

[0037] The polymer emulsions described herein may also contain a surfactant. In some embodiments, the surfactant is anionic or nonionic. In some embodiments, the surfactant contains one or more fatty alcohol alkoxylates. In another embodiment, the one or more fatty alcohol alkoxylates are fatty alcohol ethoxylates, fatty alcohol propoxylates, or any combination thereof. In some embodiments, the surfactant contains one or more ethylene oxide / propylene oxide block copolymers. In some embodiments, the surfactant contains one or more fatty alcohol ethoxylates. In some embodiments, the surfactant contains one or more alkyl sulfosuccinate ethoxylates. In some embodiments, the surfactant contains one or more fatty alcohols having an alkyl chain length of about 12 to about 18 carbons; and a degree of ethoxylation of about 10 moles to about 80 moles of ethylene oxide units. In some embodiments, the surfactant includes a nonionic surfactant. In some embodiments, the surfactant includes an anionic surfactant. In some embodiments, the anionic surfactant includes one or more alkyl sulfonates, alkylbenzene sulfonates, alkyl sulfates, alkylbenzene sulfates, phosphates, phosphinates, fatty carboxylates, or any combination of two or more thereof.

[0038] Generally, the amount of surfactant employed may vary from 0.1% to 1% by weight, based on the total amount of monomers to be polymerized.

[0039] In some embodiments, the damping formulation may include at least one of a filler, a defoamer, a rheology modifier, an emulsifier (ie, a "dispersant"), a coalescing agent, a pigment, or a biocide.

[0040] In some embodiments, the damping formulation may include one or more fillers, which may account for about 40% to about 90% by weight of the formulation, or 45% to 85% by weight, or 50% to 80% by weight, or any value or sub-range within these ranges. Examples of fillers may include, but are not limited to, calcium carbonate, barium sulfate, glass fillers, magnesium carbonate, plastic microspheres, mica, powdered stone slabs, montmorillonite flakes, glass flakes, metal flakes, graphite, graphene, talc, iron oxide, clay minerals, cellulose fibers, mineral fibers, carbon fibers, glass or polymer fibers or beads, ferrites, calcium carbonate, calcium magnesium carbonate, calcium silicate, barite, ground natural or synthetic rubber, silicon dioxide, aluminum hydroxide, aluminum oxide, and mixtures thereof. In some embodiments, the damping formulation may include a mixture of any two or more such fillers.

[0041] In some embodiments, the damping formulation may include a defoaming agent. Examples of defoaming agents include S (produced by BASF), DF 540 (produced by Rhodia), 635 (produced by Solvay), MO 2170 (produced by BASF) or MO 2190 (produced by BASF). The damping formulation may contain as much defoamer as is necessary to provide the desired foaming properties. In some embodiments, the defoamer may comprise less than 1 wt % of the damping formulation. In some embodiments, the damping formulation contains greater than 0 wt % up to about 1 wt % defoamer.

[0042] In some embodiments, the damping formulation may include a thickener or rheology modifier. Examples of rheology modifiers include HS1152; HD 1152 (produced by BASF) or AS1130 (produced by BASF). The damping formulation may include as much rheology modifier as is necessary to provide the desired solution properties. In some embodiments, the formulation may include less than 1 wt % rheology modifier. In other embodiments, the formulation may include greater than 0 wt % up to about 1 wt % rheology modifier.

[0043] In some embodiments, the damping formulation comprises a dispersant. A non-limiting example of a dispersant is CX 4320 (produced by BASF). The damping formulation may contain as much dispersant as is necessary to provide the desired properties of the formulation. In some embodiments, the formulation may contain 0.1 wt % to 2.0 wt % or 0.25 wt % to 1.5 wt % or 0.5 wt % to 1.0 wt % or any value or sub-range within these ranges.

[0044] In some embodiments, the damping formulation may include a biocide. Suitable non-limiting examples of biocides include MBS (a mixture of 1,2-benzisothiazolin-3-one (2.5%) and 2-methyl-4-isothiazolin-3-one (2.5%)), MV-14 (a mixture of 5-chloro-2-methyl-2H-isothiazol-3-one and 2-methyl-2H-isothiazol-3-one in a ratio of 3:1) and CEM 2 (a mixture of 1,2-benzisothiazol-3(2H)-one (9.3%-10.7%), 2-methylisothiazol-3(2H)-one (4.7%-5.2%) and 5-chloro-2-methyl-2H-isothiazol-3-one (0.9%-1.1%)).

[0045] II. Methods of Preparing and Applying the Emulsion

[0046] The emulsion polymerization reaction of the present disclosure can be carried out in a dual feed reactor such as Figure 1 The reactor can be equipped with a water bath, a mechanical stirrer, a temperature control probe, a feed tube for monomer addition, a feed tube for initiator addition, and a reflux condenser. Typically, each tank is charged with the contents listed in Table 1 below.

[0047] Table 1. Figure 1 The charging of different vessels in the dual-feed reactor depicted in .

[0048] container Loading Can 12 Pre-emulsion (deionized water + surfactant + monomer A + optional chain transfer agent) Can 16 Pure monomer (monomer B) Can 10 Initiator (deionized water + initiator + optional buffer) Reactor 14 Reactor charge (deionized water + surfactant + seed + acid monomer)

[0049] Initially, deionized water was charged to the reactor 14, which was then heated to 85°C. Acid monomer at 80°C was added to the reactor 14 in one go, followed by an initial initiator injection from tank 10, which was pumped into the reactor 14 via pump 20. The pre-emulsion in tank 12 containing deionized water, surfactant, monomer A, and optional chain transfer agent was then pumped into the reactor 14 via pump 18. At the same time, pure monomer containing monomer A in tank 16 was pumped into the reactor 14 via pump 22. After 15 minutes of pre-emulsification, the second batch of initiator feed from tank 10 was pumped into the reactor 14. The total feed time was three hours. At the end of the pre-emulsification, the pure monomer and initiator feeds kept the reactor at 85°C for 30 minutes, and then rinse water was added to reduce the temperature to 70°C. After the chemical stripping process was completed, the reactor 14 was cooled to room temperature, and the polymer finished polymer was then filtered into a storage container.

[0050] The damping agent can be deposited on the mechanical vibration source in a variety of ways. For example, in some embodiments, the damping agent can be sprayed on the mechanical vibration source. In other embodiments, the damping agent can be coated on the mechanical vibration source.

[0051] The source of mechanical vibration can be a body capable of generating or transmitting vibrations. The LASD formulations disclosed herein can be applied to various bodies capable of generating or transmitting vibrations. Non-limiting examples of such bodies include automobile interiors; pickup truck interiors and undersides of truck beds; interior panels of trucks; walls, ceilings, and floors of motor rail cars; aerospace vehicles or devices; elevators; washing machines; clothes dryers; automatic dishwashers; and undersides of sinks.

[0052] The damping formulations provided herein can also be applied to a variety of materials including, for example, metal, steel, aluminum, plastic, wood, wallboard, or gypsum board.

[0053] III. Properties of Emulsions

[0054] When applied to a substrate, the damping formulation can provide sound attenuation at any suitable frequency (e.g., 100 Hz, 200 Hz, 300 Hz, 400 Hz, 500 Hz, etc.) over a wide temperature range. The damping formulation can provide a composite loss factor of at least 0.1 at 200 Hz in a temperature range of at least 20°C, at least 25°C, at least 30°C, at least 35°C, at least 40°C, at least 45°C, at least 50°C, at least 55°C, at least 60°C, or any range including any two of these values ​​as endpoints. For example, the formulation can provide a loss factor of at least 0.1 at 200 Hz in a temperature range of 20°C to 60°C, 30°C to 60°C, 40°C to 60°C, or any sub-range within these ranges.

[0055] In other words, the formulations herein can provide a composite loss factor of at least 0.1 at 200 Hz at a temperature of 0°C to 60°C, 0°C to 50°C, 10°C to 60°C, 20°C to 60°C, 10°C to 50°C, 20°C to 50°C, 20°C to 60°C, 30°C to 60°C, or any sub-range within any of these ranges.

[0056] Although the present invention has been described as having exemplary embodiments, the present invention can be further modified within the spirit and scope of the present disclosure. Therefore, the present application is intended to cover any variation, use or adaptation of the present invention using its general principles. In addition, the present application is intended to cover such deviations from the present disclosure within known or customary practices in the field to which the present invention belongs and within the limitations of the appended claims.

[0057] The following examples are intended to further illustrate certain aspects of the methods and compositions described herein and are not intended to limit the scope of the claims.

[0058] Example

[0059] The following examples are presented to provide those of ordinary skill in the art with a complete disclosure and description of how to prepare and evaluate the compositions and / or methods claimed herein, and are intended to be purely exemplary and not intended to limit the scope of the present disclosure. Unless otherwise indicated, parts are parts by weight, temperature units are ° C or are ambient temperature, and pressures are at or near atmospheric pressure.

[0060] Example 1: Synthesis of acrylic emulsion formulation

[0061] Initially, the polymerization reactor is charged with the required amount of deionized water, about 25% of the total surfactant amount and seed polymer. The reactor is heated to 85°C and the acid monomer is added at 80°C in one go. Then the initial initiator injection (about 25% of the total initiator solution) is added immediately at 85°C. After the initiator injection, the pre-emulsion pure monomer feed is started at the same time. After 15 minutes of pre-emulsion and pure monomer feed, the second batch of initiator feed is started. The total feed (pure monomer + pre-emulsion + initiator) time is 3 hours. At the end of pre-emulsification, the pure monomer and initiator feeds keep the reactor at 85°C for 30 minutes, and then rinse water is added to reduce the reactor temperature to 70°C. At 70°C, delayed oxidant and reductant feeds are started to reduce residual monomers. After the chemical stripping process is completed, the reaction is cooled to room temperature. Finally, the post-addition solution is added, and the reactor mixes the contents for 15 minutes, and then the polymer is filtered in a storage container.

[0062] Table 2. Mass breakdown of Formulations 1-6 .

[0063]

[0064]

[0065] Table 3. Mw distribution of Formulations 1 to 6 。

[0066] Lotion Mn M Mz Polydispersity 1 21802 218463 767367 10.06 2 13779 44918 119247 3.26 3 9143 96745 315305 10.58 4 11029 156703 639136 14.21 5 14948 72159 199749 4.83 6 11549 103824 362105 8.99

[0067] Table 4. Mass balance of standard LASD coating formulations 。

[0068] raw materials Batch size (g) Acyclic emulsion 45.0000 Deionized water 2.0200 Dispex CX 4230 0.4896 Foamaster MO 2190(WBA) 0.1530 Dipropylene glycol 1.0404 Aurasperse W7017 (black) 0.2040 Pluronic F87 (30% solution) 0.6120 Penford glue 280 2.2847 Dualite U018-130W 0.7242 Bentone CT 1.1424 Mica 13.5453 Calcium carbonate 32.2720 Rheovis AS1130 0.5100 total 100.00

[0069] Table 5. Acoustic properties of Formulations 1-6 。

[0070]

Claims

1. A polymer emulsion composition, comprising: at least one block copolymer; At least one chain transfer agent At least one surfactant wherein the composition provides a composite loss factor of at least 0.1 at 200 Hz at a temperature of 0°C to 60°C. 2 . The polymer emulsion according to claim 1 , wherein the emulsion composition has a glass transition temperature of −60° C. to 130° C.

3. The polymer emulsion composition according to claim 1, wherein Mn is 8000 to 12,000 4. The polymer emulsion composition according to claim 1, wherein Mw is 50,000 to 220,000 5. The polymer emulsion composition according to claim 1, wherein Mz is 275,00 to 700,000 The polymer emulsion composition according to claim 1 , wherein the PDI is less than 10.

7. The polymer emulsion according to claim 1, wherein the copolymer is an acrylic copolymer or a styrene-acrylic copolymer.

8. The polymer emulsion composition according to claim 1, wherein the polymer comprises functional monomers such as acrylic acid, methacrylic acid, styrene, α-methylstyrene, hydroxyethyl methacrylate, esters of acrylic acid or methacrylic acid.

9. The polymer emulsion of claim 1, wherein the chain transfer agent is present in an amount of 0.01 wt% to 1 wt% based on the total weight of the composition.

10. The polymer emulsion according to claim 1, wherein the chain transfer agent is selected from the group consisting of isooctyl mercaptopropionate (IOMPA), butyl mercaptopropionate, 2-ethylhexyl mercaptopropionate, tert-dodecyl mercaptan and thioglycerol.

11. The polymer emulsion according to claim 1, wherein the surfactant is present in an amount of 0.3 wt % to 1 wt % based on the total weight of the composition.

12. The polymer emulsion according to claim 1, wherein the surfactant is selected from the group consisting of fatty alcohol alkoxylates, fatty alcohol ethoxylates, ethylene oxide block copolymers, propylene oxide block copolymers, alkyl sulfonates, alkyl benzene sulfonates, alkyl sulfates, alkyl benzene sulfates, phosphates, phosphites or fatty carboxylates.

13. The polymer emulsion of claim 1, wherein the emulsion further comprises an aqueous resin solution, a rheology modifier, a wetting agent, a defoamer, a thickener, a stabilizer, a buffer, a salt, a preservative, a flame retardant, a biocide, a corrosion inhibitor, a crosslinking agent, a lubricant, a colorant, a dye, a wax, a fragrance, or a filler.

14. A method for producing the polymer emulsion according to claim 1 in a dual feed reactor, the method comprising (i) charging deionized water, a surfactant and a seed polymer into a polymerization reactor; (ii) adding an initiator to the reactor; (iii) feeding monomers from two separate tanks into the reactor to form a polymer composition; (iv) adding rinse water to the reactor; (v) chemically stripping the polymer composition; and (vi) filtering the polymer composition into a storage container.

15. The process of claim 14, wherein the monomer feed is ramped up and ramped down.

16. The method of claim 14, wherein the dual power feed synthesis method produces gradient molecular weight polymer chains.

17. The method of claim 14, wherein the dual power feed synthesis process produces a broad Tg of the resulting polymer dispersion.

18. The method of claim 14, wherein the dual power feed synthesis process produces a gradient Tg.

19. A substrate coated with the composition of claim 1.

20. The coated substrate of claim 19, wherein the substrate is steel, aluminum, plastic, wood, wallboard, or gypsum board.

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