Liquid useful sound damping formulations containing binder-coated opaque polymer particles

Abstract

The present invention relates to a composition comprising an aqueous dispersion of: a) binder-coated opaque polymer particles; b) extender particles; c) starch; d) a blowing agent; and e) a rheology modifier. The composition of the present invention is useful as a coating in liquid applied sound damping applications.

Description

Background Technology

[0001] This invention relates to a formulation containing an opaque polymer coated with a binder, which is suitable as a coating for liquid application type sound damping (LASD).

[0002] LASD coatings are widely used in the automotive market to reduce vibrations in rigid structures. The LASD market is primarily comprised of water-based coatings, which typically consist of dispersions of viscoelastic polymers, mineral fillers, processing additives, and baking additives. These coatings are usually applied as layers ranging from 1 mm to 5 mm thick to metal sheets and then dried at high temperatures. The dried coating eliminates resonant vibrations within the substrate and reduces the overall noise level in the application.

[0003] Automakers are constantly seeking materials that further reduce vibration and improve damping performance. While LASD coatings outperform some damping solutions (such as asphalt pads), there is still a need for even better damping solutions that can be easily applied on the production line. Summary of the Invention

[0004] In a first aspect, the present invention addresses a need in the art by providing a composition comprising an aqueous dispersion of: a) binder-coated opaque polymer particles; b) extender particles; c) starch; d) a foaming agent; and e) a rheology modifier;

[0005] The opaque polymer particles coated with the adhesive contain:

[0006] i) A water-absorbing core comprising 20% ​​to 60% by weight structural units of a salt of a carboxylic acid monomer and 40% to 80% by weight structural units of a nonionic monoene unsaturated monomer.

[0007] ii) A polymer shell having a T value in the range of 60°C to 120°C. g ;and

[0008] iii) A polymer adhesive layer superimposed on the shell, the polymer adhesive layer having a T value not exceeding 50°C. g It also contains structural units of at least one monoene unsaturated monomer;

[0009] The weight ratio of the structural unit of the monomer in the water-absorbing core to the shell is 1:10 to 1:20.

[0010] The weight ratio of the polymer adhesive layer to the sum of the structural units of the monomers in the shell and the core is in the range of 1:1 to 3.5:1; wherein

[0011] The polymer particles have a z-average particle size in the range of 300 nm to 750 nm; and the composition has a Brinell viscosity in the range of 200,000 cP to 20,000,000 cP.

[0012] The compositions of the present invention are used as coatings in liquid-based sound damping applications. Detailed Implementation

[0013] In a first aspect, the present invention is a composition comprising an aqueous dispersion of the following components: a) binder-coated opaque polymer particles; b) extender particles; c) starch; d) foaming agent; and d) rheology modifier;

[0014] The opaque polymer particles contain:

[0015] i) A water-absorbing core comprising 20% ​​to 60% by weight structural units of a salt of a carboxylic acid monomer and 40% to 80% by weight structural units of a nonionic monoene unsaturated monomer.

[0016] ii) A polymer shell having a T value in the range of 60°C to 120°C. g ;and

[0017] iii) A polymer adhesive layer superimposed on the shell, the polymer adhesive layer having a T value not exceeding 50°C. g It also contains structural units of at least one monoene unsaturated monomer;

[0018] The weight ratio of the structural unit of the monomer in the water-absorbing core to the shell is 1:10 to 1:20.

[0019] The weight ratio of the polymer adhesive layer to the sum of the structural units of the monomers in the shell and the core is in the range of 1:1 to 3.5:1; wherein

[0020] The polymer particles have a z-average particle size in the range of 300 nm to 750 nm; and the composition has a Brinell viscosity in the range of 200,000 cP to 20,000,000 cP.

[0021] The binder-coated opaque pigment polymer particles comprise a water-absorbing core, a shell superimposed on the core, and an binder superimposed on the shell. The water-absorbing core comprises structural units of a salt of a carboxylic acid monomer, based on the weight percentage of structural units of the monomers in the core, ranging from 20% by weight, preferably from 25% by weight, more preferably from 30% by weight, and most preferably from 32% by weight to 60% by weight, preferably to 50% by weight, more preferably to 40% by weight, and most preferably to 36% by weight.

[0022] As used herein, the term "structural unit" refers to the residue of the monomer after polymerization. For example, the structural unit of a salt of methacrylic acid, wherein M... + The counter ion is preferably lithium, sodium, or potassium, as shown in the figure:

[0023]

[0024] Examples of suitable carboxylic acid monomers include acrylic acid, methacrylic acid, itaconic acid, and maleic acid.

[0025] The water-absorbing core also comprises, by weight, structural units of a nonionic monoene unsaturated monomer from 40% to 50% to 60% (preferably from 64% to 80% to 75% to 70% to 70% to 68% to 68% by weight, based on the monomer structural units in the core. Examples of nonionic monoene unsaturated monomers include one or more acrylates and / or methacrylates, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, isobornyl methacrylate, lauryl methacrylate, and cyclohexyl methacrylate; and one or more monoene unsaturated aromatic compounds, such as styrene, α-methylstyrene, and 4-tert-butylstyrene. A preferred nonionic monoene unsaturated monomer is methyl methacrylate.

[0026] The polymer shell preferably has a T value within the range of not less than 80°C, more preferably not less than 90°C, and most preferably not less than 95°C, and most preferably not more than 115°C, and most preferably not more than 110°C. g As used in this article, T g It refers to the glass transition temperature calculated using the Fox equation.

[0027] Preferably, the shell comprises structural units of methyl methacrylate, styrene, α-methylstyrene, isobornyl methacrylate, lauryl methacrylate, acrylonitrile, or cyclohexyl methacrylate. In one embodiment, the shell comprises at least 70% by weight of styrene structural units.

[0028] The polymer shell may further contain 0.2% to 5% by weight of other polyene unsaturated monomers (such as allyl methacrylate (ALMA), divinylbenzene (DVB), trimethylolpropane trimethacrylate (TMPTMA) or trimethylolpropane triacrylate (TMPTA)) structural units.

[0029] As used herein, "polymer binder" refers to a polymeric material that forms a film on a desired substrate with or without a coalescing agent. The Tb of the polymer binder is calculated using the Fox equation. g The temperature shall not exceed 50°C or 35°C; and shall not fall below -20°C or -10°C. Examples of suitable polymeric adhesives include acrylic, styrene-acrylic, vinyl esters such as vinyl acetate and vinyl neodecanoate, and vinyl ester-vinyl polymeric adhesives. Acrylic adhesives comprising methyl methacrylate structural units and one or more acrylate structural units such as methyl acrylate, ethyl acrylate, n-butyl acrylate, or 2-ethylhexyl acrylate are particularly preferred, as are styrene-acrylic adhesives.

[0030] Preferably, the weight ratio of the structural units of the core monomers to the shell in the polymer particles is in the range of 1:12 to 1:16. Preferably, the weight ratio of the polymer binder to the sum of the structural units of the core monomers and the shell in the polymer particles is in the range of 1.2:1, more preferably from 1.5:1, and most preferably from 1.8:1 to preferably 3.0:1, more preferably to 2.5:1, and most preferably to 2.2:1.

[0031] The z-average particle size of the polymer particles is in the range of 300 nm, 400 nm, 450 nm, or 475 nm to 700 nm, 600 nm, or 550 nm. As used herein, z-average particle size refers to the particle size determined by dynamic light scattering, for example, using a BI-90 Plus particle size analyzer (Brookhaven). The binder-coated polymer particles can be prepared as described in US7,691,942 B2 and the Examples section below.

[0032] The composition also contains extender particles, which typically have a median average diameter (D) in the range of 1 µm to 50 µm. 50 Particle size. Examples of suitable extender particles (also referred to as fillers in the art) include calcium carbonate; silica; alumina; kaolin; clay; talc; graphite; mica; diatomaceous earth; glass powder, fibers, or microspheres; aluminum hydroxide; perlite; barium sulfate; magnesium carbonate; calcium dihydrate; rock wool; wollastonite; zeolite; ceramic and thermoplastic microspheres; polymer fibers and cross-linked rubber particles. A combination of calcium carbonate and mica is preferred as extender particles. The weight ratio of extender particles to binder-coated opaque polymer particles is preferably in the range of 20:80 to 80:20. Preferably, the extender particles and binder-coated opaque pigment particles constitute at least 90% by weight or at least 95% by weight of the components other than water in the composition.

[0033] The composition also comprises starch (typically potato starch or corn starch), a foaming agent that expands upon heating (such as commercially available Expansionl 031 WUF 40 microspheres), and a rheology modifier (such as an alkali-swellable emulsion). Defoamers, dispersants, and surfactants are advantageously used in the preparation of the compositions of the present invention, and the compositions may also preferably contain colorants. The composition has a Brinell viscosity in the range of 200,000 cP or 500,000 cP to 20,000,000 cP or to 10,000,000 cP. As used herein, “Brownian viscosity” refers to Brinell viscosity under non-shear conditions. The method for measuring Brinell viscosity is described below.

[0034] The composition can be used at 0.35 kg / m 2 or 1kg / m 2 Up to 10kg / m 2 An areal density (i.e., wet areal density) within a certain range is applied to a metal substrate, followed by baking at a temperature ranging from 100°C to 200°C to dry and cure the composition. The areal density (i.e., dry areal density) of the cured coating is 0.3 kg / m³. 2 Or 0.5kg / m 2 Up to 5kg / m 2 Within the range. Wet surface density refers to the mass of the uncured coated sample minus the mass of the substrate, divided by the area of ​​the metal substrate; similarly, the dry surface density of the sample is the mass of the dry substrate minus the mass of the uncoated substrate, divided by the area of ​​the metal substrate. Examples of suitable metals include steel, stainless steel, iron, aluminum, magnesium, and titanium. Surprisingly, the study found that binder-coated opaque polymer particles provided improved damping compared to cured LASD formulations containing binder and opaque polymer particles as separate components.

[0035] Surprisingly, the study found that binder-coated opaque polymer particles provided improved damping compared to cured LASD formulations containing binders and opaque polymer particles as different components.

[0036] Example

[0037] In the following intermediate examples, MMA refers to methyl methacrylate; MAA refers to methacrylic acid; AA refers to acrylic acid; BA refers to n-butyl acrylate; PEM refers to ethyl 2-phosphate methacrylate; CHMA refers to cyclohexyl methacrylate; LOFA refers to linseed oil fatty acids; AN refers to acrylonitrile; ALMA refers to allyl methacrylate; DVB refers to divinylbenzene; NaPS refers to sodium persulfate; t-BHP refers to tert-butyl hydroperoxide; IAA refers to isoascorbic acid; EDTA refers to the tetrasodium salt of ethylenediaminetetraacetic acid; DMEA refers to dimethylethanolamine; and Core #1 refers to an aqueous dispersion of polymer particles (66 MMA / 34 MAA, 32.0% solids, z-average particle size of 135 nm) prepared substantially as described in US 6,020,435.

[0038] Intermediate Example 1 — Preparation of OAP 1

[0039] The 5L four-necked round-bottom flask is equipped with a paddle stirrer, thermometer, N2 inlet, and reflux condenser. Add DI water (500g) to the container and heat to 89°C under N2.

[0040] Immediately add NaPS (1.90 g in 20 g water) to the vessel, followed by Core #1 (125 g). Then, over 85 minutes, add monomer emulsion 1 (ME 1) prepared by mixing DI water (125.0 g), Disponil FES-32 emulsifier (10.0 g), styrene (436.8 g), linseed oil fatty acids (2.8 g), AN (112.0 g), and DVB (7.0 g) to the reactor. The reaction temperature, initially controlled at 78 °C at the start of ME 1 feeding, is increased to 84 °C after 40 minutes and to 92 °C after 55 minutes. Two minutes after the start of ME 1 addition, add a solution of AA (5.6 g) in DI water (35 g) to the flask.

[0041] Forty minutes after the start of ME 1 addition, 0.5 g of NaPS solution (in 30 g of water) was added to the reactor over a period of 45 minutes. After the ME 1 feed was complete, the reaction was cooled to 72°C.

[0042] When the reactor temperature reaches 80°C, an aqueous mixture of ferrous sulfate and EDTA (20 g, 0.1 wt% FeSO4 and 2 g, 1 wt% EDTA) is added to the reactor. When the reactor temperature reaches 72°C, a co-feed containing a solution of 1.9 g mixed with DI water (100 g) and NaPS (5.0 g), along with a separate solution of IAA (2.6 g in 100 g water), is simultaneously added to the reactor at a rate of 1.2 g / min. Two minutes after the start of the co-feed solution loading, ME 2, prepared by mixing DI water (260 g), Disponil FES-32 emulsifier (17.0 g), BA (543.6 g), MMA (409.2 g), and PEM (67.2 g, 60% active), is added to the reactor over 55 minutes while the temperature is raised to 80°C without any additional external heat. Thirty minutes after the start of ME 2 addition, 13.8 g of 1-dodecanethiol was added to ME 2 while thoroughly mixed. After the ME 2 addition was complete, the addition of the co-feed solution was stopped and the batch was kept at 80°C for 5 minutes. Then, an NH 4OH solution (5 g, 28% by weight aqueous solution) mixed with DI water (5.0 g) was added to the reactor along with hot (90°C) DI water (225 g).

[0043] ME 3, prepared by mixing DI water (54.0 g), Disponil FES-32 emulsifier (3.0 g), BA (104.4 g), MMA (75.6 g), and 4-hydroxyTEMPO (3.0 g), was fed into the reactor over 5 minutes. Immediately after the ME 3 feed was completed, NH 4OH (83.3 g, 28% wt% aqueous solution) mixed with DI water (35 g) was added to the reactor over 3 minutes. The batch was held for 5 minutes after the NH 4OH addition was complete. The co-feed solution was then restarted at a rate of 1.2 g / min until complete. An additional co-feed of DI water (25 g) containing t-BHP (1.5 g), along with a separate solution of IAA (0.7 g) in water (25 g), was simultaneously added to the reactor at a rate of 1.2 g / min. After the second co-feed addition was complete, the dispersion was cooled to 25°C. When the reactor temperature reaches 45°C, ACRYSOL will be added within 10 minutes. ™ A solution of ASE-60 thickener (trademark of Dow Chemical Company or its affiliates, 13.35 g in 53 g of water) was added to the reactor. The dispersion was filtered to remove any condensation. The filtered opaque acrylic polymer dispersion (OAP) had a solids content of 48.1%.

[0044] Intermediate Example 2 — Preparation of OAP 2

[0045] Intermediate Example 2 was prepared essentially as described for the preparation of intermediate Example 1, except that ALMA (5.6 g) was used instead of DVB in the preparation of ME1. The filtered opaque acrylic polymer dispersion (OAP) had a solids content of 48.7%.

[0046] Intermediate Example 3 — Preparation of OAP 3

[0047] A 5-liter four-necked round-bottom flask was equipped with a paddle stirrer, thermometer, N2 inlet, and reflux condenser. DI water (500 g) was added to the vessel and heated to 89°C under N2. NaPS (1.90 g in 20 g water) was immediately added to the vessel, followed by Core #1 (125 g). Monomer emulsion 1 (ME 1), prepared by mixing DI water (125.0 g), Disponil FES-32 emulsifier (10.0 g), styrene (380.8 g), LOFA (2.8 g), AN (112.0 g), CHMA (56.0 g), and DVB (7.0 g), was then added to the vessel over 85 minutes. The reaction temperature, initially controlled at 78°C at the start of the ME 1 feed, was increased to 84°C after 40 minutes, and then to 92°C after 55 minutes. Two minutes after the start of ME 1 addition, a solution of AA (5.6 g) in DI water (35 g) was added to the flask. Forty minutes after the start of ME 1 addition, a NaPS solution (0.5 g in 30 g water) was added to the reactor over a period of 45 minutes. After the ME 1 feed was complete, the reaction was cooled to 72°C.

[0048] When the reactor temperature reaches 80°C, an aqueous mixture of ferrous sulfate and EDTA (20 g, 0.1 wt% FeSO4 and 2 g, 1 wt% EDTA) is added to the reactor. When the reactor temperature reaches 72°C, a co-feed containing a solution of t-BHP (1.9 g) and NaPS (5.0 g) mixed with DI water (100 g), along with a separate solution of IAA (2.6 g in 100 g water), is simultaneously added to the reactor at a rate of 1.2 g / min. Two minutes after the start of adding the co-feed solution, ME 2, prepared by mixing DI water (260 g), Disponil FES-32 emulsifier (17.0 g), BA (543.6 g), MMA (409.2 g), and PEM (67.2 g, 60% active), is added to the reactor over 55 minutes while the temperature is raised to 80°C without any external heat supply. Thirty minutes after the start of ME 2 addition, 1-dodecanethiol (13.8 g) was added to ME 2 under mixing. After the ME 2 addition was complete, the addition of the co-feed solution was stopped and the batch was kept at 80°C for 5 minutes. Then, an NH 4OH solution (5 g, 28% by weight aqueous solution) mixed with DI water (5.0 g) was added to the reactor along with hot (90°C) DI water (225 g).

[0049] ME 3, prepared by mixing DI water (54.0 g), Disponil FES-32 emulsifier (3.0 g), BA (104.4 g), MMA (75.6 g), and 4-hydroxyTEMPO (3.0 g), was fed into the reactor over 5 minutes. Immediately after the ME 3 feed was completed, NH4OH (70.0 g, 28% by weight aqueous solution) mixed with DI water (35 g) was added to the reactor over 3 minutes. The batch was held for 5 minutes after the NH4OH addition was complete. The co-feed solution was then restarted at a rate of 1.2 g / min until complete. An additional co-feed of DI water (25 g) containing t-BHP (1.5 g), along with a separate solution of IAA (0.7 g) in water (25 g), was simultaneously added to the reactor at a rate of 1.2 g / min. After the second co-feed addition was complete, the dispersion was cooled to 25°C. When the reactor temperature reaches 45°C, ACRYSOL will be added within 10 minutes. ™ A solution of ASE-60 thickener (13.35 g in 53 g water) was added to the reactor. The dispersion was filtered to remove any clumps. The filtered opaque acrylic polymer dispersion (OAP) had a solids content of 48.3%.

[0050] Intermediate Example 4 — Preparation of OAP 4

[0051] A 5-liter four-necked round-bottom flask was equipped with a paddle stirrer, thermometer, N2 inlet, and reflux condenser. DI water (500 g) was added to the vessel and heated to 89°C under N2. NaPS (1.90 g in 20 g water) was immediately added to the vessel, followed by Core #1 (125 g). Monomer emulsion 1 (ME 1), prepared by mixing DI water (125.0 g), Disponil FES-32 emulsifier (10.0 g), styrene (380.8 g), LOFA (2.8 g), AN (112.0 g), CHMA (56.0 g), and DVB (7.0 g), was then added to the vessel over 85 minutes. The reaction temperature, initially controlled at 78°C at the start of the ME 1 feed, was increased to 84°C after 40 minutes, and then to 92°C after 55 minutes. Two minutes after the start of ME 1 addition, a solution of AA (5.6 g) in DI water (35 g) was added to the flask. Forty minutes after the start of ME 1 addition, a NaPS solution (0.5 g in 30 g water) was added to the reactor over a period of 45 minutes. After the ME 1 feed was complete, the reaction was cooled to 72°C.

[0052] When the reactor temperature reaches 80°C, an aqueous mixture of ferrous sulfate and EDTA (20 g, 0.1 wt% FeSO4 and 2 g, 1 wt% EDTA) is added to the reactor. When the reactor temperature reaches 72°C, a co-feed containing a solution of t-BHP (1.9 g) and NaPS (5.0 g) mixed with DI water (100 g), along with a separate solution of IAA (2.6 g in 100 g water), is simultaneously added to the reactor at a rate of 1.2 g / min. Two minutes after the start of the co-feed solution loading, ME 2, prepared by mixing DI water (260 g), Disponil FES-32 emulsifier (17.0 g), BA (598.8 g), MMA (409.2 g), and MAA (12.0 g), is added to the reactor over 55 minutes while the temperature is raised to 80°C without any external heat supply. Thirty minutes after the start of ME2 addition, 1-dodecanethiol (13.8 g) was added to ME2 while thoroughly mixed. After the ME2 addition was complete, the addition of the co-feed solution was stopped and the batch was kept at 80°C for 5 minutes. Then, an NH4OH solution (5 g, 28% by weight aqueous solution) mixed with DI water (5.0 g) was added to the reactor along with hot (90°C) DI water (225 g).

[0053] ME 3, prepared by mixing DI water (54.0 g), Disponil FES-32 emulsifier (3.0 g), BA (104.4 g), MMA (75.6 g), and 4-hydroxyTEMPO (3.0 g), was fed into the reactor over 5 minutes. Immediately after the ME 3 feed was completed, NH4OH (70.0 g, 28% by weight aqueous solution) mixed with DI water (35 g) was added to the reactor over 3 minutes. The batch was held for 5 minutes after the NH4OH addition was complete. The co-feed solution was then restarted at a rate of 1.2 g / min until complete. An additional co-feed of DI water (25 g) containing t-BHP (1.5 g), along with a separate solution of IAA (0.7 g) in water (25 g), was simultaneously added to the reactor at a rate of 1.2 g / min. After the second co-feed addition was complete, the dispersion was cooled to 25°C. When the reactor temperature reaches 45°C, ACRYSOL will be added within 10 minutes. ™ A solution of ASE-60 thickener (13.35 g in 53 g water) was added to the reactor. The dispersion was filtered to remove any clumps. The filtered opaque acrylic polymer dispersion (OAP) had a solids content of 48.2%.

[0054] Comparative Example 1 of Intermediates — Preparation of Acrylic Adhesive

[0055] A 5-liter four-necked round-bottom flask was equipped with a paddle stirrer, thermometer, N2 inlet, and reflux condenser. DI water (952 g) and Disponil FES-32 (1.76 g) were added to the flask and heated to 88°C under N2. A monomer emulsion was prepared by mixing DI water (550.7 g), Disponil FES-32 (49.25 g), 1-dodecylthiol (20.48 g), BA (1191.9 g), MMA (890.75 g), and PEM (68.95 g, 60% active). A portion of the monomer emulsion (133 g) was added to the flask, followed by ammonium persulfate (5.3 g in 48 g water). After noticing the peak exothermic reaction, the remaining monomer emulsion was added to the flask over 80 minutes; simultaneously, ammonium persulfate (2.3 g in 96 g water) was added to the flask over 80 minutes. Once the monomer emulsion and ammonium persulfate solution have been fed, the contents are cooled to 75°C.

[0056] While cooling, ammonium hydroxide (7.43 g 28% solution in 18.7 g water), an aqueous mixture of ferrous sulfate and EDTA (14 g, 0.1 wt% FeSO4 and 1.4 g, 1 wt% EDTA), t-BHP (1.9 g 70% solution in 11 g water), and IAA (1.3 g in 24 g water) were added sequentially to the flask. When the temperature reached 75°C, additional t-BHP (1.9 g 70% solution in 11 g water) was added to the flask, followed by IAA (3 g in 47 g water) over 20 minutes. The flask was then cooled to below 40°C. When the temperature reached 50°C, DMEA (65.8 g in 53 g water) was added to the flask over 10 minutes. The dispersion was then filtered to remove any condensate.

[0057] Comparative Example 2 of Intermediates — Preparation of Dispersions of Opaque Polymer Particles

[0058] A 5-liter four-necked round-bottom flask was equipped with a paddle stirrer, thermometer, N2 inlet, and reflux condenser. DI water (730.64 g) and acetic acid (0.28 g in 1.64 g water) were added to the flask and heated to 89°C under N2. Sodium persulfate (NaPS, 3.39 g in 24.55 g water) was immediately added to the flask, followed by core #1 (218.53 g). Monomer emulsion 1 (ME 1), prepared by mixing DI water (69.55 g), Polystep A-16-22 emulsifier (5.5 g), styrene (69.95 g), MAA (8.43 g), and MMA (61.53 g), was then added to the flask over 60 minutes. The reaction temperature was maintained constant at 78°C during ME 1 feeding, and a DI water rinse solution (32.73 g) was added at completion. Upon completion of ME 1 feeding, monomer emulsion 2 (ME 2), prepared by mixing DI water (217.64 g), Polystep A-16-22 emulsifier (11.09 g), styrene (657 g), linseed oil fatty acids (4.17 g), allyl methacrylate (2.13 g), and methacrylic acid (12.6 g), was fed into the vessel over 60 minutes. The temperature of the reaction mixture was increased to 84°C after 15 minutes and to 92°C after 25 minutes. Simultaneously with the start of ME 2 feeding, a NaPS solution (0.93 g in 62.18 g of water) was co-fed into the vessel over 65 minutes. After ME2 feed is complete, 32.73 g of DI water rinse solution is added to the container, followed by an aqueous mixture of ferrous sulfate and EDTA (16.36 g, 0.1 wt% FeSO4 and 1.64 g, 1 wt% EDTA) and DI water (182.45 g, >60 °C), and the reaction is maintained at 90 °C to 92 °C for 15 minutes. During the holding period, 182.48 g of DI water (>60 °C) is added to the container.

[0059] ME 3, prepared by mixing DI water (57.27 g), Polystep A-16-22 emulsifier (2.05 g), styrene (167.73 g), and 4-hydroxyTEMPO (1.88 g), was fed into the container within 5 minutes, and its temperature was lowered to 85°C. Immediately after the ME 3 feed was completed, 32.73 g of DI water rinse solution was added to the container, followed by the addition of sodium hydroxide (NaOH, 29.45 g, 50 wt% aqueous solution) mixed with DI water (572.73 g, >60°C) to the container within 10 minutes. The batch was held for 5 minutes after the NaOH addition was complete. After holding, a post-polymerization solution of t-BHP (2.12 g, 70 wt% aqueous solution) in DI water (24.55 g) was added to the container, and an aqueous solution (65.45 g) of isoascorbic acid (IAA, 1.1 g) was fed into the container within 25 minutes. After the second co-feed is added, DI water (94.11 g) is added to the container, and the dispersion is cooled to room temperature and filtered to remove any condensate.

[0060] Table 1 shows the components and amounts used in the preparation of LASD wet formulations. TAMOL, TERGITOL, and ACRYSOL are trademarks of Dow Chemical Company or its affiliates. Starch refers to Penford Gum 200 potato starch; foaming agent refers to Expansel 031 WUF 40 foaming agent; and thickener refers to ACRYSOL. ™ ASE-60 thickener. All units are parts by weight (pbw).

[0061] Table 1 — LASD wet process formulations

[0062]

[0063] Prepare the coating formulation from the components listed in Table 1 in the order listed. Mix the components with a top-mounted stirrer for 10 minutes, then allow to equilibrate overnight.

[0064] Viscosity measurement

[0065] For coatings with viscosities between 1,000,000 centipoise (cP) and 10,000,000 cP, Brookfield RV DV-I+ viscometers with Brookfield Helipath supports and T-Bar TE rotors were used to measure Brookfield viscosity at 25°C. Brookfield T-Bar TC and TF rotors can be used for viscosities between 200,000 and 1,000,000 cP and between 10,000,000 and 20,000,000 cP, respectively. The rotors rotated at 0.5 rpm and were run for 120 seconds (i.e., under shear-free conditions) before measurement. The support allows the rotor to move downwards into the coating during rotation to ensure accurate measurement of high-viscosity materials. Brookfield viscosity (BV) is expressed in centipoise (cP) × 10⁻⁶. 4 Measurements are taken in units.

[0066] Table 2 shows the corrected material amount (pbw) for LASD dry formulations.

[0067] Table 2 — LASD Dry Formulations

[0068]

[0069] Preparation of coated substrate

[0070] The LASD formulation was manually applied to a hardened carbon steel Oberst bar measuring 1.6 mm × 12.7 mm × 200 mm to produce a wet surface density of 4 kg / m³. 2 Up to 5kg / m 2 The coating is then cured at ambient temperature for 30 minutes, followed by baking at 150°C for 30 minutes to produce a coating with a strength of 3 kg / m³. 2 The dry surface density of the cured coating was determined. After cooling, the coated rods were tested according to ASTM E-756 to determine the composite loss factor (CLF, a measure of damping performance) at seven different temperatures (9°C, 19°C, 29°C, 39°C, 48°C, 58°C, and 69°C) and an interpolation frequency of 200 Hz. Table 3 shows the measured CLF values ​​for all compositions at each temperature.

[0071] Table 3 — Area Under the CLF Curve

[0072]

[0073] The CLF value measured at each temperature is summed to calculate a measure of the overall damping performance independent of the peak temperature (CLF). SUMThe overall damping performance was determined using [a method to determine the overall damping performance]. The viscosity of the samples ranged from 500,000 cP to 2,000,000 cP. Table 4 shows the CLF values ​​of the examples. SUM .

[0074] Table 4 — Characteristics of Cured LASD Coatings

[0075]

[0076] Data show that cured coatings formed from compositions containing binder-coated opaque polymer particles exhibit improved damping properties compared to compositions prepared using opaque polymer particles and different binder particles or binder particles alone. Notably, cured formulations containing only binder particles exhibit better damping properties than formulations containing a combination of binder particles and opaque polymer particles.

Claims

1. A composition comprising an aqueous dispersion of the following components: a) binder-coated opaque polymer particles; b) extender particles; c) starch; d) foaming agent; and e) rheology modifier; The adhesive-coated opaque polymer particles comprise: i) A water-absorbing core comprising 20% ​​to 60% by weight structural units of a carboxylic acid monomer salt and 40% to 80% by weight structural units of a nonionic monoene unsaturated monomer. ii) A polymer shell having a T value in the range of 60°C to 120°C. g ;and iii) A polymer adhesive layer superimposed on the shell, the polymer adhesive layer having a T value not exceeding 50°C. g It also contains structural units of at least one monoene unsaturated monomer; The weight ratio of the structural units of the monomer in the water-absorbing core to the shell is 1:10 to 1:

20. The weight ratio of the polymer adhesive layer to the sum of the structural units of the monomers in the shell and the core is in the range of 1:1 to 3.5:1; wherein The polymer particles have a z-average particle size in the range of 300 nm to 750 nm; and the composition has a Brinell viscosity in the range of 200,000 cP to 20,000,000 cP.

2. The composition according to claim 1, wherein the weight ratio of the extender particles to the binder-coated opaque polymer particles is preferably in the range of 20:80 to 80:

20.

3. The composition according to claim 2, wherein the binder-coated opaque polymer particles and extender particles comprise at least 90% by weight of the components in the composition excluding water.

4. The composition of claim 3, wherein the water-absorbing core of the binder-coated opaque polymer particles comprises 30% to 40% by weight of the structural units of the carboxylic acid monomer salt based on the weight of the structural units of the monomer in the core, and 60% to 70% by weight of the structural units of the nonionic monoene unsaturated monomer based on the weight of the shell.

5. The composition according to claim 4, wherein the carboxylic acid monomer is acrylic acid or methacrylic acid; the nonionic monomer is an acrylate or methacrylate selected from the group consisting of: ethyl acrylate, n-butyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, isobornyl methacrylate, lauryl methacrylate, and cyclohexyl methacrylate; and the shell has a To in the range of 90°C to 115°C. g .

6. The composition according to claim 5, wherein the nonionic monomer is methyl methacrylate, and at least 70% by weight of the shell is composed of styrene structural units.

7. The composition according to claim 3, wherein the extender particles are calcium carbonate; silicon dioxide; alumina; kaolin; clay; talc; graphite; mica; diatomaceous earth; glass powder, fiber or microspheres; aluminum hydroxide; perlite; barium sulfate; magnesium carbonate; calcium dihydrate; rock wool; wollastonite; zeolite; ceramic or thermoplastic microspheres; polymer fiber or cross-linked rubber particles.

8. The composition of claim 6, wherein the filler particles are a combination of calcium carbonate and mica particles; wherein the composition has a Brookfield viscosity in the range of 500,000 cP to 10,000,000 cP.

9. The composition according to claim 1, wherein the starch is potato starch, and wherein the composition further comprises an antifoaming agent, a dispersant, a surfactant, and a colorant.

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