Acrylic damping additives for filled thermoplastics

Abstract

A sound damping additive comprises an core comprising an acrylic polymer having a glass transition temperature, Tg, ranging from -60° C to less than 0° C, as calculated by the Fox equation. The acrylic polymer of the core is not crosslinked. A shell comprising a polymer having a Tg greater than 50° C is formed on the core. A thermoplastic resin composition comprises the sound damping additive, a filler, and a thermoplastic resin, where the sound damping additive is present in an amount of 10 wt% or less relative to the total weight of the thermoplastic resin composition. Articles produced from the resin composition are also disclosed.

Description

ACRYLIC DAMPING ADDITIVES FOR FILLED THERMOPLASTICSFIELD OF THE INVENTION

[0001] The present invention generally relates to acrylic additives and, more specifically, to acrylic damping additives for filled thermoplastics and filled thermoplastics comprising acrylic damping additives.DESCRIPTION OF THE RELATED ART

[0002] Rigid thermoplastics containing fillers are widely used in many markets for a variety of applications where noise, vibration and harshness, collectively referred to as NVH, is a critical performance metric. These rigid thermoplastics are typically highly filled with 10 to 50 wt% mineral filler, such as calcium carbonate, talc, or mica.

[0003] For example, vinyl flooring filled with calcium carbonate or wollastonite is a rapidly growing market and includes multilayer resilient vinyl flooring such as luxury vinyl tile (LVT), stone polymer composite (SPC), solid polymer composite, rigid floor, waterproof polymer composite, or wood polymer composite (WPC), which has the appearance of hardwood or ceramic tile.

[0004] One of the major drawbacks of vinyl flooring, including resilient flooring, is that the sound of the vinyl flooring does not match the look. Vinyl resilient flooring has a distinct sound during its usage. During use, vinyl resilient flooring will emit noise either through movement within the room (heels clicking) or to a floor below the room (footsteps, furniture dragging). In both cases, the typical acoustic properties of vinyl flooring are not desirable. Wood is known to produce a characteristic sound within a room when walked on. Even though vinyl flooring may have a wood-like appearance, the sound it makes is unlike wood and ruins the illusion. In addition, there is a need to limit the amount of vibration transmitted through the floor to the room below. Specific applications such as medical facilities, schools, and libraries require low sound transmission.

[0005] Several strategies have been employed to improve the NVH performance of vinyl flooring, including adding thick elastomeric pads to the underside and using specialized acoustic fillers. Some manufacturers have designed their flooring to include a viscoelastic layer embedded in the structure, i.e., a constrained layer, which reduces vibrations, but is a costly solution that lacks desired performance. Other strategies employed require the use of an underlayment, such as rubber or cork sheets. The use of an underlayment requires an additional installation step that is labor intensive and the underlayment still may not meet the sound reduction target.

[0006] For example, U.S. Patent No. 8,640,824 discloses a vinyl tile with a constrained acoustical portion comprising a crumb rubber component, a polyurethane foam, and a resin binder. The crumb rubber can be made from recycled tires or sneaker rubber.

[0007] U.S. Patent Application Publication No. 2014 / 0302294 discloses a constrained layer in an acoustical vinyl tile that comprises individual layers chosen from any variety of rubber, cork, and polyurethane foam.

[0008] U.S. Patent No. 8,146,310 discloses a noise controlling system that comprises a system for controlling noise. The system comprises multiple layers including a net layer with multiple polymer filaments and air to create a void space.

[0009] These attempts to dampen noise require complex changes to existing production lines, as well as require multiple components to attenuate noise.

[0010] Alternative attempts have been made at sound damping through the use of additives. For example, WO 2016 / 130639 discloses the use of styrene-isobutylene-styrene block copolymers (BCPs) as additives to a blend of thermoplastic elastomers. Similarly, WO 2019 / 230872 discloses the use of styrene / isobutene BCPs as additives to improve damping performance.

[0011] JP 2017-186390 discloses dry acrylic core-shell particles for use in combination with curable materials on their own as a damping coating.

[0012] WO 2023 / 163871 discloses a sound damping composition comprising an acrylic sound damping polymer that is disposed on the surface of a filler and a thermoplastic resin composition comprising the sound damping composition and a thermoplastic resin.

[0013] Sound damping materials have also been developed for liquid applied sound damping (LASD) applications. Due to the low glass transition temperatures (Tg) of those sound damping materials, they cannot be isolated in dry powdered forms.

[0014] There is a great need for sound damping additives that can be easily incorporated into existing manufacturing processes, provide sound damping at low loading levels, minimizer the impact on other physical properties, and / or are cost effective.BRIEF SUMMARY OF THE INVENTION

[0015] The present invention provides a sound damping additive comprising a core comprising an acrylic polymer having a glass transition temperature, Tg, ranging from -60 °C to less than 0 °C, as calculated by the Fox equation. The acrylic polymer of the core is not crosslinked. A shell comprising a polymer having a Tggreater than 50 °C is formed on the core.

[0016] The present invention also provides a thermoplastic resin composition comprising the sound damping additive, a filler, and a thermoplastic resin. The sound damping additive is present in an amount of 10 wt% or less relative to the total weight of the thermoplastic resin composition.

[0017] The present invention also provides articles produced from the thermoplastic resin composition.A BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 shows a diagram of the setup for performing center point excitation tests.

[0019] FIG. 2 shows a comparison of damping performance at 25 °C of examples according to embodiments of the invention.DETAILED DESCRIPTION OF THE INVENTION

[0020] The present invention provides a powdered sound damping additives that may easily be incorporated into filled thermoplastic compositions. The sound damping additive comprises a core comprising an acrylic polymer having a shell comprising a high Tgpolymer formed thereon. The sound damping additive is capable of attenuating vibrations, or sound, particularly when used in a thermoplastic composition. The sound damping additive may attenuate single frequencies of vibration, all frequencies or vibrations, or one or more bands of vibration frequencies. For example, the sound damping additive may attenuate vibration frequencies created by footsteps when a person walks across the vinyl floor.

[0021] As used herein, the terms “glass transition temperature” or “Tg” refers to the temperature at or above which a glassy polymer will undergo segmental motion of the polymer chain. Glass transition temperatures of a copolymer can be estimated using the Fox equation (Bulletin of the American Physical Society, 1 (3) Page 123 (1956)) as follows:1 / Tg = w1 / Tg(1 ) + w2 / Tg(2)

[0022] For a copolymer, w1 and w2 refer to the weight fraction of the two comonomers, and Tg(1 ) and Tg(2) refer to the glass transition temperatures of the two corresponding homopolymers made from the monomers in degrees Kelvin. For polymers containing three or more monomers, additional terms are added (wn / Tg(n)). The glass transition temperatures of the homopolymers may be found, for example, in the “Polymer Handbook,” edited by J. Brandrup and E.H. Immergut, Interscience Publishers. The Tg of a polymer can also be measured by various techniques, including, for example, differential scanning calorimetry (“DSC”). As used herein, the phrase “calculated Tg” shall mean the glass transition temperature as calculated by the Fox equation. When the Tg of a multistage polymer ismeasured, more than one Tg may be observed. The Tg observed for one stage of a multistage polymer may be the same as the Tg that is characteristic of the polymer that forms that stage (i.e., the Tg that would be observed if the polymer that forms that stage were formed and measured in isolation from the other stages). When a monomer is said to have a certain Tg, it is meant that a homopolymer made from that monomer has that Tg.

[0023] The acrylic polymer of the core has a calculated glass transition temperature, Tg, ranging from -60 °C to 0 °C as calculated by the Fox equation. The acrylic polymer of the core has a glass transition temperature of at least -60 °C, preferably at least -50 °C, more preferably at least -40 °C, even more preferably at least -35 °C, and yet more preferably at least -30 °C, as measured by DSC. The acrylic polymer of the core has a calculated glass transition temperature of no more than 0 °C, preferably no more than -5 °C, more preferably no more than -10°C, , and even more preferably no more than -15 °C.

[0024] The acrylic polymer of the core is not crosslinked. The acrylic polymer of the core may be linear or branched, but contains substantially no crosslinking (i.e., less than 2 mol% of monomeric units in the acrylic polymer of the core are crosslinked, preferably less than 1 mol%, more preferably less than 0.5 mol%, even more preferably less than 0.1 mol%, and still more preferably 0 mol% of the monomeric units in the acrylic polymer of the core are crosslinked). Preferably, the acrylic polymer of the core is linear.

[0025] The acrylic polymer of the core may comprise a homopolymer or a copolymer, such as, for example a block copolymer. The acrylic polymer of the core may comprise a 100 wt% acrylic polymer or may comprise a non-acrylic component (i.e., non-acrylic structural units). When a non-acrylic component is used, the acrylic component comprises at least 50 wt% of the total weight of the acrylic polymer of the core, more preferably at least 60 wt%, even more preferably at least 70 wt%, and still more preferably at least 80 wt% of the total weight of the acrylic polymer of the core.

[0026] The acrylic polymer of the core may comprise one or more structural units (i.e., the remnant of the monomer after polymerization) selected from a, p-ethylenically unsaturated carboxylic acid monomers and ethylenically unsaturated nonionic monomers. Examples of suitable a, p-ethylenically unsaturated carboxylic acid monomers include monobasic acids such as (meth)acrylic acid, crotonic acid, and acyloxypropionic acid; and dibasic acid monomers such as maleic acid, fumaric acid, and itaconic acid; or mixtures thereof. Preferred a, p-ethylenically unsaturated carboxylic acid monomers include acrylic acid, methacrylic acid, or mixtures thereof. Examples of ethylenically unsaturated nonionic monomers include, for example, alkyl esters of (meth)acrylic acids including C1 -C18 and preferably C1 -C12 alkyl esters of (meth)acrylic acids such as methyl acrylate, ethyl acrylate,butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, lauryl acrylate, methyl methacrylate, butyl methacrylate, isodecyl methacrylate, lauryl methacrylate, hydroxy-functional (meth)acrylic acid alkyl ester such as hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate. Preferred ethylenically unsaturated nonionic monomers are butyl acrylate, butyl methacrylate, methyl methacrylate, 2-ethylhexyl acrylate, decyl acrylate, lauryl acrylate, isodecyl methacrylate, lauryl methacrylate, and mixtures thereof.

[0027] The acrylic polymer of the core may also comprise one or more structural units derived from functionalized monomers. For example, the acrylic polymer of the core may comprise structural units derived from at least one organo-phosphorus monomer. The organo-phosphorus monomer may be in the acid form or as a salt of the phosphorus acid groups. Examples of organo-phosphorus monomers include:organic group containing an acryloxy, methacryloxy, or a vinyl group, and R’ and R” are independently selected from H and a second organic group. The second organic group may be saturated or unsaturated. Suitable organo-phosphorus monomers include dihydrogen phosphate-functional monomers such as dihydrogen phosphate esters of an alcohol in which the alcohol also contains a polymerizable vinyl or olefinic group, such as allyl phosphate, mono- or diphosphate of bis(hydroxy-methyl) fumarate or itaconate, derivatives of (meth)acrylic acid esters, such as, for examples phosphates of hydroxyalkyl(meth)acrylates including 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylates, and the like.

[0028] Other suitable organo-phosphorous monomers include CH2=C(R) — C(O) — O — (R’O)n — P(O)(OH)2, where R=H or -CH3, R’=alkyl, and n=1 to 5, such as the methacrylates SIPOMER™ PAM-100, SIPOMER™ PAM-200, SIPOMER™ PAM-400, SIPOMER™ PAM-600 and the acrylate, SIPOMER™ PAM-300, available from Solvay.

[0029] Other suitable organo-phosphorus monomers are phosphonate functional monomers, disclosed in WO 99 / 25780 A1 , and include vinyl phosphonic acid, allylphosphonic acid, 2-acrylamido-2-methylpropanephosphonic acid, a-phosphonostyrene, 2- methylacrylamido-2-methylpropanephosphonic acid. Further suitable organo-phosphorus monomers are 1 ,2-ethylenically unsaturated (hydroxy)phosphinylalkyl (meth)acrylate monomers, disclosed in U.S. Pat. No. 4,733,005, and include (hydroxy)phosphinylmethyl methacrylate.

[0030] Preferably, the organo-phosphorus monomers comprise at least one compound of formula CH2=C(R) — C(O) — O — (R’O)n— P(O)(OH)2. More preferably, R is -CH3, R’ is an alkyl group comprising 1 to 6 carbon atoms, and n=1 .

[0031] In a preferred embodiment, the acrylic polymer of the core comprises a phosphate functionalized linear acrylic copolymer comprising structural units derived from phosphoethylmethacrylate (PEM).

[0032] The acrylic polymer of the core may comprise one or more structural units selected from a compound of formula R’SiORs, where R is hydrogen or a group comprising 1 to 6 carbon atoms, and R’ is a substituted or unsubstituted alkyl group comprising 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms.

[0033] The acrylic polymer of the core may comprise other structural units, such as, for example, amines (e.g., Ra nNHn, where R is a substituted or unsubstituted alkyl group comprising 1 to 12 carbon atoms and n is an integer from 0 to 3), or a functionalized (meth)acrylate (e.g., glycidyl methacrylate).

[0034] Other non-acrylic components that may be present in the acrylic polymer of the core include structural units selected from styrene and substituted styrenes; butadiene; ethylene, propylene, a-olefins such as 1 -decene; and vinyl monomers such as vinyl acetate, vinyl butyrate, vinyl chloride, vinylidene chloride, vinyl versatate and other vinyl esters; or combinations thereof.

[0035] Examples of acrylic polymers comprising a non-acrylic component include, but are not limited to styrene / acrylic copolymers and polyvinylacetate / acrylic copolymers.

[0036] The acrylic polymer of the core has a shell comprising a high Tgpolymer formed thereon, i.e., the sound damping additive is in the form of a core-shell polymer. As used herein, the term “high Tgpolymer” means a polymer have a Tggreater than 50 °C. Preferably the high Tgpolymer has a Tggreater than 60 °C, more preferably greater than 70 °C, and even more preferably greater than 80 °C.

[0037] The high Tgpolymer preferably comprises an acrylic polymer. The high Tgpolymer may comprise one or more structural units selected from a, p-ethylenically unsaturated carboxylic acid monomers and ethylenically unsaturated nonionic monomers. Examples of suitable a, p-ethylenically unsaturated carboxylic acid monomers include monobasic acidssuch as (meth)acrylic acid, crotonic acid, and acyloxypropionic acid; and dibasic acid monomers such as maleic acid, fumaric acid, and itaconic acid; or mixtures thereof. Preferred a, p-ethylenically unsaturated carboxylic acid monomers include acrylic acid, methacrylic acid, or mixtures thereof. Examples of ethylenically unsaturated nonionic monomers include, for example, alkyl esters of (meth)acrylic acids including C1 -C18 and preferably C1 -C12 alkyl esters of (meth)acrylic acids such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, lauryl acrylate, methyl methacrylate, butyl methacrylate, isodecyl methacrylate, lauryl methacrylate, hydroxy-functional (meth)acrylic acid alkyl ester such as hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate. Preferred ethylenically unsaturated nonionic monomers are butyl acrylate, butyl methacrylate, methyl methacrylate, 2-ethylhexyl acrylate, decyl acrylate, lauryl acrylate, isodecyl methacrylate, lauryl methacrylate, and mixtures thereof.

[0038] Other non-acrylic components that may be present in the high Tgpolymer, including, for example, structural units selected from styrene and substituted styrenes; butadiene; ethylene, propylene, a-olefins such as 1 -decene; and vinyl monomers such as vinyl acetate, vinyl butyrate, vinyl chloride, vinylidene chloride, vinyl versatate and other vinyl esters; or combinations thereof.

[0039] The high Tgpolymer may further comprise a chain transfer agent, such as, for example, dodecylmercaptan, butylmercaptopropionate, methylmercaptopropionate, mercaptopropionic acid, etc.

[0040] Preferably, the core comprises at least 50 wt% of the total weight of the acrylic polymer core and the high Tgpolymer shell. More preferably, the core comprises at least 60 wt%, and even more preferably at least 70 wt%, of the total weight of the core and the shell. The core comprises less than 99 wt% of the total weight of the core and the shell, preferably less than 95 wt%, and more preferably less than 90 wt% of the total weight of the core and the shell.

[0041] The acrylic polymer of the core and the high Tgpolymer of the shell are preferably produced by emulsion polymerization in which the acrylic polymer of the core is prepared first, followed by forming the high Tgpolymer of the shell on the core.

[0042] The sound damping additive is in the form of a dried powder. The sound damping additive, e.g., the core-shell particles formed by emulsion polymerization, may be isolated and dried by spray drying or coagulation.

[0043] The powdered sound damping additive may be incorporated into a sound damping composition comprising the sound damping additive and a filler. For example, the powder sound damping additive and the filler may be dry mixed to form a sound damping compositionthat may then be used in a filled thermoplastic composition. Alternatively, the powdered sound damping additive may be incorporated into a thermoplastic composition comprising the sound damping additive, a filler, and a thermoplastic resin to form a filled thermoplastic composition.

[0044] The filler may be a single filler or a combination of two or more fillers that differ in at least one property such as type of filler, method of preparation, treatment or surface chemistry, filler composition, filler shape, filler surface area, average particle size, and / or particle size distribution.

[0045] The shape and dimensions of the filler is also not specifically restricted. For example, the filler may be spherical, rectangular, ovoid, irregular, and may be in the form of, for example, a powder, a flour, a fiber, a flake, a chip, a shaving, a strand, a scrim, a wafer, a wool, a straw, a particle, and combinations thereof. Dimensions and shape are typically selected based on the type of the filler utilized, the selection of other components included within the composition, and the end use application of the polymer composite article formed therewith. Preferably, the average particle size of the filler is 50 pm or less. More preferably, the average particle size of the filler is 25 pm or less, even more preferably 10 pm or less, still more preferably 5 pm or less, and yet more preferably 1 pm or less.

[0046] Non-limiting examples of fillers include quartz and / or crushed quartz, aluminum oxide, magnesium oxide, silica (e.g. fumed, ground, precipitated), hydrated magnesium silicate, magnesium carbonate, dolomite, silicone resin, wollastonite, soapstone, kaolinite, kaolin, mica muscovite, phlogopite, halloysite (hydrated alumina silicate), aluminum silicate, sodium aluminosilicate, glass (fiber, beads or particles, including recycled glass, e.g. from wind turbines or other sources), clay, magnetite, hematite, calcium carbonate such as precipitated, fumed, and / or ground calcium carbonate, calcium sulfate, barium sulfate, calcium metasilicate, zinc oxide, talc, diatomaceous earth, iron oxide, clays, mica, chalk, titanium dioxide (titania), zirconia, sand, carbon black, graphite, anthracite, coal, lignite, charcoal, activated carbon, non-functional silicone resin, alumina, silver, metal powders, , magnesium oxide, magnesium hydroxide, magnesium oxysulfate fiber, aluminum trihydrate, aluminum oxyhydrate, coated fillers, carbon fibers (including recycled carbon fibers, e.g. from the aircraft and / or automotive industries), poly-aramids such as chopped KEVLAR™ or Twaron™, nylon fibers, mineral fillers or pigments (e.g. titanium dioxide, non-hydrated, partially hydrated, or hydrated fluorides, chlorides, bromides, iodides, chromates, carbonates, hydroxides, phosphates, hydrogen phosphates, nitrates, oxides, and sulfates of sodium, potassium, magnesium, calcium, and barium); zinc oxide, antimony pentoxide, antimony trioxide, beryllium oxide, chromium oxide, lithopone, boric acid or a borate salt suchas zinc borate, barium metaborate or aluminum borate, mixed metal oxides such as vermiculite, bentonite, pumice, perlite, fly ash, clay, and silica gel; rice hull ash, ceramic and, zeolites, metals such as aluminum flakes or powder, bronze powder, copper, gold, molybdenum, nickel, silver powder or flakes, stainless steel powder, tungsten, barium titanate, silica-carbon black composite, functionalized carbon nanotubes, cement, slate flour, pyrophyllite, sepiolite, zinc stannate, zinc sulphide), and combinations thereof. Preferably, the filler is selected from the group consisting of calcium carbonate, glass fibers, carbon fibers, mica, graphite, talc, kaolin, aluminum trihydrate, and combinations thereof. More preferably, the filler comprises calcium carbonate.

[0047] A further aspect of the present invention relates to a thermoplastic resin comprising the sound damping additive, a filler, and a thermoplastic resin. The thermoplastic resin may be selected from the group consisting of polyvinyl chloride, polypropylene, acrylic, polyester, polycarbonate, polyethylene, and polyphenylene oxide. Preferably, the thermoplastic resin is selected from polyvinyl chloride and acrylic. More preferably, the thermoplastic resin comprises polyvinyl chloride.

[0048] The sound damping additive is present in an amount ranging from 0.5 to 10 wt% relative to the total weight of the thermoplastic resin composition. More preferably, the sound damping additive is present in an amount ranging from 1 to 8 wt% relative to the total weight of the thermoplastic resin composition. Even more preferably, the sound damping additive is present in an amount ranging from 1 to 6 wt% relative to the total weight of the thermoplastic composition.

[0049] Preferably, the filler is present in an amount ranging from 10 wt% to 80 wt% relative to the total weight of the thermoplastic resin composition. Preferably, the filler is present in an amount of at least 15 wt%, and more preferably of at least 20 wt% relative to the total weight of the thermoplastic resin composition. Preferably, the filler is present in an amount of 70 wt% or less, and more preferably 60 wt% or less relative to the total weight of the thermoplastic resin composition.

[0050] The thermoplastic resin composition may be used to produce articles, such as floor tiles. Floor tiles often comprise thermoplastic resins, such as polyvinyl chloride, in at least one layer. The sound damping composition of the present invention may be incorporated into the thermoplastic resin using existing manufacturing processes. The sound damping composition can be added in powdered form as an additive during compounding of filled thermoplastics. By incorporating the sound damping composition of the present invention into a polyvinyl chloride floor tile, sound damping performance can be significantly improved, even with substantially small amounts of the sound damping additive present.Examples

[0051] Sound damping additives were prepared by emulsion polymerization to form coreshell sound damping additives according to the formulations shown in Table 1 , where the values correspond to percentages by weight.Table 1BA = butyl acrylateMMA = methyl methacrylateMAA = methacrylic acidSty = styrene nDDM = n-dodecylmercaptan

[0052] To form SDA 1 , a monomer emulsion was prepared by mixing deionized water (437.27 g), sodium lauryl sulfate (24.66 g, 28% aqueous solution), followed by BA (1222 g), MMA (107.43 g), and nDDM (13.43 g).

[0053] A 5 gallon reactor equipped with a mechanical stirrer, nitrogen gas blanket, thermometer, condenser, heating mantel and temperature controller was charged with deionized water (754.09 g) and heated to 35 °C while purged with nitrogen. To this reactor were added SSF (2 g) in water (13.62 g), 208.34 g of a separately prepared polymer seed (15% solids, 100 nm weighted average particle size) comprised of BA and MMA, 181 .19 g of monomer emulsion 1 in water (48.55 g), and a solution of tBHP (0.16 g, 70% aqueous solution). When the reaction mixture reached 48 °C, 362.73 g of the monomer emulsion in water (48.55 g), and a solution of tBHP (0.3 g, 70% aqueous solution) in water (0.6 g) were added, to allow the exothermic reaction to reach 72 °C. The reaction mixture was then cooled to 53 °C, followed by the addition of 724.75 g of the monomer emulsion in water (48.55 g), and a solution of tBHP (0.58 g, 70% aqueous solution) in water (0.6 g), to allow the exothermic reaction to reach 87 °C. When reaction mixture was cooled to68 °C, 536.5 g of the monomer emulsion in water (26 g), and a solution of tBHP (0.46 g, 70% aqueous solution)in water (0.6 g) were added to allow the exothermic reaction to reach 86 °C. At the peak temperature, sodium lauryl sulfate (73.12 g, 28% aqueous solution) in water (4.21 g) was added, followed by SSF (0.28 g) in water (3.5 g), and a solution of tBHP (0.1 g, 70% aqueous solution) in water (0.65 g). The reaction mixture was then cooled to 49 °C, followed by the addition of MMA (357.13 g) in water (29.13 g), SSF (0.52 g) in water (13.72 g), a solution of sodium persulfate (0.52 g) in water (13.33 g), and water (16.18 g). When the reaction mixture reached 66 °C, a solution of SSF (0.1 g) in water (10.97 g), and a solution of sodium persulfate (0.1 g) in water (10.65 g) were fed into the reactor over 10 minutes while the reaction mixture was cooled to room temperature. The resulting emulsion polymer was spray dried to yield a white powder.

[0054] The other sound damping additives, SDA 2 to SDA 5, were prepared in a similar manner.

[0055] A polyvinyl chloride (PVC) masterbatch composition was prepared by sequentially adding the components according to Table 2. The master batch was prepared in around 20 minutes by adding the PVC at room temperature to a Gunther Papenmeier / Welex blender, ramping the power to 15A, adding TM 181 at 125°F, adding the lubricant package at 150°F, adding acrylic processing aids at 190°F, and adding CaCOs at 195°F.Table 2

[0056] PVC flooring formulations were prepared by mixing the PVC masterbatch (PVC MB) with the sound damping additives prepared above. The formulations are shown in Table 3 where the values are in PHR, i.e., parts per hundred resin). The core / shell sound dampingadditive was mixed with the PVC masterbatch in a paper cup prior to processing. The PVC formulation was milled at 185°C for 3 minutes on an electric Collin Roll mill with a 0.3 mm gap, then the milled sheet was compression molded to 3.2mm thick plaque at 190°C.Table 3Damping Tests - DMA

[0057] The plaques were tested on the TA Instruments Q-800 Dynamic Mechanical Analyzer (DMA) using single cantilever clamp fixtures. The plaques were cut into the exact dimensions needed for this geometry, and the width and thicknesses were measured for each sample and input into the program. The length was fixed at 17.5 mm because of the geometry of the clamp. The sample was placed in the back portion of the clamp nearest the thermocouple and tightened in the order center clamp first, then end clamp. A calibrated torque wrench was used at 10 lbs force. The plaques were tested in the range of 0 °C to 180 °C, at a heating rate of 2 °C / min using the Temp Ramp / Freq Sweep Test in the DMA Multi-Frequency-Strain Mode. The applied frequency was 1 Hz. The Procedure Parameters were as follows: Applied Strain = 0.002 % and a Soak Time of 5 minutes was employed before the start of data acquisition. The dynamic storage and loss moduli (E’ and E” respectively) as well as tan 5 were recorded as a function of temperature. Each sample was run in duplicate as two plaques were provided. For initial screening, samples were tested by dynamic mechanical analysis.Damping Tests - Center Point Excitation

[0058] To explore the full mechanical clamping response of the composites, PVC samples were tested using the center impedance method commonly employed to assess damping. Testing was performed in accordance with JIS G 0602-1993 for center-supporting, steady exciting methods. However, a homogenous damped bar was used instead of a coated one, with slightly altered dimensions. Sample plaques were cut into 10x1 inch bars and a metal mounting quill was superglued to the center of the bar. The quill was then screwed onto an impedance head attached to a mechanical vibration exciter unit as shown in Figure 1 . The vibration device with attached bar was placed in an environmental chamber to allow testing at 25 °C. The bar was excited using white noise and the frequency response function was captured from 0-5000 Hz. For these samples, this allowed measurement of the composite loss factor or CLF of modes 1 -5. CLF was calculated using the 3 dB down technique for each mode.

[0059] The results of the center point excitation damping tests are shown in FIG. 2. A control sample using Durcal 10 calcium carbonate was prepared without any sound damping additive. As shown in FIG. 2, each of the PVC formulations comprising the sound damping additives according to the present invention demonstrated significantly improved sound damping.Definitions and Usage of Terms

[0060] Unless otherwise indicated by the context of the specification, all amounts, ratios and percentages are by weight, and all test methods are current as of the filing date of this disclosure. The articles “a”, “an” and “the” each refer to one or more. It is to be understood that the appended claims are not limited to express and particular compounds, compositions, or methods described in the detailed description, which may vary between particular embodiments which fall within the scope of the appended claims. With respect to any Markush groups relied upon herein for describing particular features or aspects of various embodiments, different, special, and / or unexpected results may be obtained from each member of the respective Markush group independent from all other Markush members. Each member of a Markush group may be relied upon individually and or in combination and provides adequate support for specific embodiments within the scope of the appended claims.

[0061] Further, any ranges and subranges relied upon in describing various embodiments of the present invention independently and collectively fall within the scope of the appended claims, and are understood to describe and contemplate all ranges including whole and / or fractional values therein, even if such values are not expressly written herein. One of skill inthe art readily recognizes that the enumerated ranges and subranges sufficiently describe and enable various embodiments of the present invention, and such ranges and subranges may be further delineated into relevant halves, thirds, quarters, fifths, and so on. As just one example, a range “of from 0.1 to 0.9” may be further delineated into a lower third, i.e., from 0.1 to 0.3, a middle third, i.e., from 0.4 to 0.6, and an upper third, i.e., from 0.7 to 0.9, which individually and collectively are within the scope of the appended claims, and may be relied upon individually and / or collectively and provide adequate support for specific embodiments within the scope of the appended claims. In addition, with respect to the language which defines or modifies a range, such as “at least,” “greater than,” “less than,” “no more than,” and the like, it is to be understood that such language includes subranges and / or an upper or lower limit. As another example, a range of “at least 10” inherently includes a subrange of from at least 10 to 35, a subrange of from at least 10 to 25, a subrange of from 25 to 35, and so on, and each subrange may be relied upon individually and / or collectively and provides adequate support for specific embodiments within the scope of the appended claims. Finally, an individual number within a disclosed range may be relied upon and provides adequate support for specific embodiments within the scope of the appended claims. For example, a range “of from 1 to 9” includes various individual integers, such as 3, as well as individual numbers including a decimal point (or fraction), such as 4.1 , which may be relied upon and provide adequate support for specific embodiments within the scope of the appended claims.

[0062] The term “composition,” as used herein, includes material(s) which comprise the composition, as well as reaction products and decomposition products formed from the materials of the composition.

[0063] The term “comprising,” and derivatives thereof, is not intended to exclude the presence of any additional component, step or procedure, whether or not the same is disclosed herein. In order to avoid any doubt, all compositions claimed herein through use of the term “comprising” may include any additional additive, adjuvant, or compound, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term, “consisting essentially of” excludes from the scope of any succeeding recitation any other component, step or procedure, excepting those that are not essential to operability. The term “consisting of” excludes any component, step or procedure not specifically delineated or listed.

[0064] The term “polymer,” as used herein, refers to a polymeric compound prepared by polymerizing monomers, whether of the same or a different type. The generic term polymer thus embraces the term homopolymer (employed to refer to polymers prepared from only one type of monomer, with the understanding that trace amounts of impurities can be incorporated into the polymer structure), and the term copolymer (employed to refer topolymers prepared from more than one type of monomer). Trace amounts of impurities may be incorporated into and / or within the polymer.

[0065] “Blend”, “polymer blend” and like terms mean a composition of two or more polymers. Such a blend may or may not be miscible. Such a blend may or may not be phase separated. Such a blend may or may not contain one or more domain configurations, as determined from transmission electron spectroscopy, light scattering, x-ray scattering, and any other method known in the art. Blends are not laminates, but one or more layers of a laminate may contain a blend.

Claims

CLAIMSWhat is claimed is:1 . A sound damping additive comprising: a core comprising an acrylic polymer, wherein the acrylic polymer of the core has a calculated glass transition temperature, Tg, ranging from -60 °C to less than 0 °C, as calculated by the Fox equation, wherein the acrylic polymer of the core is not crosslinked,; and a shell formed on the core, wherein the shell comprises a polymer having a Tggreater than 50 °C.

2. The sound damping additive of claim 1 , wherein the composition is in the form of a powder.

3. The sound damping additive of claim 1 or 2, wherein the acrylic polymer of the core comprises a styrene / acrylic copolymer or a polyvinylacetate / acrylic copolymer.

4. The sound damping additive of claim 1 or 2, wherein the acrylic polymer of the core comprises a phosphate functionalized linear acrylic copolymer.

5. The sound damping additive of any one of the preceding claims, wherein the polymer of the shell comprises an acrylic polymer.

6. The sound damping additive of claim 5, wherein the polymer of the shell comprises methyl methacrylate structural units.

7. The sound damping additive of claim, wherein the core is present in an amount ranging from 50 to 99 wt% of the total weight of the core and the shell.

8. A thermoplastic resin composition comprising: the sound damping additive of any one of the preceding claims; a filler; and a thermoplastic resin; wherein the sound damping additive is present in an amount of 10 wt% or less relative to the total weight of the thermoplastic resin composition.

9. The thermoplastic resin composition of claim 8, wherein the thermoplastic resin is selected from the group consisting of polyvinyl chloride, polypropylene, acrylic, polyester, polycarbonate, polyethylene, and polyphenylene oxide.

10. The thermoplastic resin composition of claim 8 or 9, wherein the sound damping additive is present in an amount of 8 wt% or less relative to the total weight of the thermoplastic resin composition.1 1. The thermoplastic resin composition of any one of claims 8 to 10, wherein the filler is selected from the group consisting of calcium carbonate, glass fibers, carbon fibers, mica, graphite, talc, kaolin, aluminum trihydrate, and combinations thereof.

12. The thermoplastic resin composition of any one of claims 8 to 11 , wherein the filler is present in an amount ranging from 10 to 800 wt% relative to the total weight of the thermoplastic resin composition.

13. The thermoplastic resin composition of claim 12, wherein the filler is present in an amount ranging from 20 to 60 wt% relative to the total weight of the thermoplastic resin composition.

14. An article produced from the thermoplastic resin composition of any one of claims 8 to 13.

15. The article of claim 14, wherein the article is a floor tile.

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