Thermoplastic polyolefin compositions with impact toughness and improved damping

Abstract

A thermoplastic polyolefin resin composition comprises a thermoplastic polyolefin resin matrix, a filler, and a sound damping additive. The sound damping additive comprises an acrylic vibrational damping polymer having a glass transition temperature, Tg, ranging from -60 C to less than 0 C, as calculated by the Fox equation. The acrylic vibrational damping polymer is not crosslinked. Articles produced from the thermoplastic polyolefin resin composition are also disclosed.

Description

THERMOPLASTIC POLYOLEFIN COMPOSITIONS WITH IMPACT TOUGHNESS AND IMPROVED DAMPINGFIELD OF THE INVENTION

[0001] The present invention generally relates to thermoplastic polyolefin compositions and, more specifically, to thermoplastic polyolefin compositions having impact toughness and improved damping.DESCRIPTION OF THE RELATED ART

[0002] Thermoplastic polyolefin (TPO) compounds are commonly used in the automotive industry. TPO compounds find use in both interior and exterior automotive applications, such as, door trim panels, airbag covers, instrument panels, and bumper fascia.

[0003] TPO compounds generally comprise a thermoplastic polyolefin (e.g., polypropylene) as the matrix polymer, impact modifiers, a reinforcing filler, and additives for color, thermal and UV stability, and processing aids.

[0004] Improving passenger comfort and experience is becoming of increasing importance in the automotive industry for OEMs to provide differentiation to consumers. With the transition from internal combustion engine (ICE) vehicles to battery electric vehicles (BEVs) certain types of noise and vibration may be more noticeable to vehicle occupants. Due to quieter electric motors, passengers in BEVs are exposed to different noise and vibration profiles when compared to ICE vehicles. With the implementation of autonomous driving, vehicle occupants may expect improved aesthetics and comfort, including reduced noise, vibration, and harshness, collectively known as NVH, in the vehicle cabin. There are several materials used for NVH control in vehicles today, such as, for example, liquid applied sound damping materials and other vibration absorbing materials, but if interior and exterior TPO panels had improved damping properties, the overall NVH characteristics of the vehicle could be improved, or steps to add damping materials to TPO panels could be eliminated.

[0005] It is critical to maintain the other critical properties of the TPO, such as stiffness, impact toughness, and processability (injection molding flowability), while improving the damping performance.

[0006] 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.

[0007] JP 2017-186390 discloses dry acrylic core-shell particles for use in combination with curable materials on their own as a damping coating.

[0008] 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, minimize the impact on other physical properties, and / or are cost effective.SUMMARY OF THE INVENTION

[0009] The present invention provides a thermoplastic polyolefin resin composition comprising a thermoplastic polyolefin resin matrix, a filler, and a sound damping additive. The sound damping additive comprises an acrylic sound damping polymer having a glass transition temperature, Tg, ranging from -60 °C to less than 0 °C, as calculated by the Fox equation. The acrylic vibrational damping polymer is not crosslinked.

[0010] The present invention also provides articles produced from the thermoplastic polyolefin resin composition.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 shows a diagram of the setup for performing center point excitation tests.DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention provides a thermoplastic polyolefin resin composition comprising a thermoplastic polyolefin resin matrix, a filler, and a sound damping additive. The sound damping additive comprises an acrylic vibrational damping polymer. As used herein, an “acrylic vibrational damping polymer” refers to an acrylic polymer or copolymer that is capable of attenuating vibrations, or sound, particularly when used in a thermoplastic composition. The acrylic vibrational damping polymer may attenuate single frequencies of vibration, all frequencies or vibrations, or one or more bands of vibration frequencies.

[0013] The thermoplastic polyolefin resin matrix comprises a polymer selected from a propylene-based polymer, ethylene-based polymer, or styrene-based polymer. Preferably, the thermoplastic polyolefin resin matrix comprises propylene-based polymer. The term “ethylene-based polymer” and like terms, as used herein, refers to a polymer that comprises, in polymerized form, a majority weight percent of ethylene monomer (based on the weight of the polymer), and optionally may comprise one or more comonomers. Suitable, nonlimiting examples of ethylene-based polymer include ethylene homopolymer and ethylene / a-olefin copolymer, such as high density polyethylene (HDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), very low density polyethylene (VLDPE), andultra-low density polyethylene (ULDPE). Nonlimiting examples of suitable o-olefins include C3-C20 a-olefins. Representative a-olefins include propylene, 1 -butene, 1 -pentene, 1 - hexene, 1 -heptene, and 1 -octene. The term “styrene-based polymer” and like terms, as used herein, refers to a polymer that comprises, in polymerized form, a majority weight percent of styrene monomer (based on the weight of the polymer), and optionally may comprise one or more comonomers. The term “propylene-based polymer” and like terms, as used herein, refers to a polymer that comprises, in polymerized form, a majority weight percent of propylene monomer (based on the weight of the polymer), and optionally may comprise one or more comonomers. Suitable, nonlimiting examples of propylene-based polymer include propylene homopolymer (homopolymer polypropylene), propylene / a-olefin copolymer (random copolymer polypropylene), propylene impact copolymer (impact copolymer polypropylene), and combinations thereof. Nonlimiting examples of suitable a-olefins include C2 and C4-C20 a-olefins. Representative a-olefins include ethylene, 1 -butene, 1 -pentene, 1 - hexene, 1 -heptene, and 1 -octene. Propylene impact copolymer is a heterophasic polymer wherein a rubber phase (or a discontinuous phase) of discrete domains of ethylene / propylene copolymer is dispersed throughout a matrix phase (or a continuous phase) or propylene homopolymer or propylene / a-olefin copolymer. The propylene impact copolymer contains from 1 wt% to 40 wt%, or from 5 wt% to 25 wt%, or from 8 wt% to 15 wt% ethylene / propylene rubber phase, based on the total weight of the propylene impact copolymer. Preferably, the propylene-based polymer is a propylene impact copolymer. The propylene-based polymer has a melt flow rate (MFR) from 0.1 g / 10 min to 500 g / 10 min, or from 1 g / 10 min to 150 g / 10 min, or from 30 g / 10 min to 140 g / 10 min.

[0014] The thermoplastic polyolefin resin matrix comprises at least 40 wt% of the total weight of the thermoplastic polyolefin resin composition. Preferably, the thermoplastic polyolefin resin matrix comprises at least 45 wt%, more preferably at least 50 wt%, and still more preferably at least 55 wt% of the total weight of the thermoplastic polyolefin resin composition. The thermoplastic polyolefin resin matrix comprises 85 wt% or less, preferably 80 wt% or less, more preferably 75 wt% or less, and even more preferably 70 wt% or less, of the total weight of the thermoplastic polyolefin resin composition.

[0015] 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.

[0016] 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, forexample, 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.

[0017] 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 such as 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), natural fibers (such as hemp, agave, wood, jute, kenaf, bagasse, or coffee chaff) 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 talc.

[0018] The filler is present in an amount of at least 5 wt% relative to the total weight of the thermoplastic polyolefin resin composition. Preferably, the filler is present in an amount of at least 8 wt%, and more preferably of at least 10 wt% relative to the total weight of the thermoplastic polyolefin resin composition. The filler is present in an amount of 40 wt% or less, preferably 30 wt% or less, and even more preferably 20 wt% or less, relative to the total weight of the thermoplastic polyolefin resin composition.

[0019] The damping additive comprises an acrylic vibrational damping polymer. The acrylic vibrational damping polymer has a calculated glass transition temperature, Tg, ranging from -60 °C to 0 °C as calculated by the Fox equation. The acrylic vibrational damping polymer 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 vibrational damping polymer 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.

[0020] 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)

[0021] 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 is measured, more than one Tg may be observed. The Tg observed for one stage of a multistage polymer may be the same as the T g 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.

[0022] The acrylic vibrational damping polymer is not crosslinked. The acrylic vibrational damping polymer may be linear or branched, but contains substantially no crosslinking (i.e.,less than 2 mol% of monomeric units in the acrylic vibrational damping polymer 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 vibrational damping polymer are crosslinked). Preferably, the acrylic vibrational damping polymer is linear. Preferably, the acrylic vibrational damping polymer comprises at least 50 wt% of the total weight of the sound damping additive. More preferably, the acrylic vibrational damping polymer comprises at least 60 wt%, and even more preferably at least 70 wt%, of the total weight of the sound damping additive.

[0023] The acrylic vibrational damping polymer may be a homopolymer or a copolymer, such as, for example a block copolymer. The acrylic vibrational damping polymer may be 100 wt% acrylic 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 vibrational damping polymer, 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 vibrational damping polymer.

[0024] The acrylic vibrational damping polymer 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.

[0025] The acrylic vibrational damping polymer may also comprise one or more structural units derived from functionalized monomers. For example, the acrylic vibrational damping polymer 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 thephosphorus acid groups. Examples of organo-phosphorus monomers include:where R is an 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.

[0026] Other suitable organo-phosphorous monomers include CH2=C(R)— C(O)— 0— (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.

[0027] Other suitable organo-phosphorus monomers are phosphonate functional monomers, disclosed in WO 99 / 25780 A1 , and include vinyl phosphonic acid, allyl phosphonic 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.

[0028] 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 .

[0029] In a preferred embodiment, the acrylic vibrational damping polymer comprises a phosphate functionalized linear acrylic copolymer comprising structural units derived from phosphoethylmethacrylate (PEM).

[0030] The acrylic vibrational damping polymer 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.

[0031] The acrylic vibrational damping polymer may comprise other structural units, such as, for example, amines (e.g., R3nNHn, 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).

[0032] Other non-acrylic components that may be present in the acrylic vibrational damping polymer 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.

[0033] Examples of acrylic vibrational damping polymers comprising a non-acrylic component include, but are not limited to styrene / acrylic copolymers and polyvinylacetate / acrylic copolymers.

[0034] The acrylic vibrational damping polymer may be added to the thermoplastic polyolefin resin composition in a liquid form, or it may be further processed to prepare the sound damping additive in a powder form. To prepare a powdered sound damping additive, the acrylic vibrational damping polymer may be prepared as a core-shell particle wherein the acrylic vibrational damping polymer forms the core and a high Tgpolymer shell is formed on the acrylic vibrational damping polymer core. Alternatively, the acrylic vibrational damping polymer may be disposed on a surface of the filler and then dried to form a powder.

[0035] In embodiments wherein the sound damping additive is in the form of a core-shell particle, the acrylic vibrational damping polymer has a high Tgpolymer shell formed thereon. 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. The high Tgpolymer shell may provide additional vibrational damping to the core-shell particle.

[0036] The high Tgpolymer shell preferably comprises an acrylic polymer. The high Tgpolymer may comprise one or more structural units selected from a, [3-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.

[0037] 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.

[0038] The high Tgpolymer may further comprise a chain transfer agent, such as, for example, dodecylmercaptan, butylmercaptopropionate, methylmercaptopropionate, mercaptopropionic acid, etc.

[0039] The high Tgpolymer shell comprises less than 50 wt% of the total weight of the sound damping additive. Preferably, the high Tgpolymer shell comprises less than 40 wt%, and more preferably less than 30 wt%, of the total weight of the sound damping additive. The high Tgpolymer shell comprises at least 1 wt% of the total weight of the sound damping additive, preferably at least 5 wt%, and more preferably at least 10 wt% of the total weight of the sound damping additive. The high Tgpolymer shell will affect the overall Tgof the coreshell particle comprising the acrylic vibrational damping polymer core and the high Tgshell. The ratio of the high Tgshell to the acrylic vibrational damping polymer core can be selected to achieve the desired overall Tgof the core-shell particle such that the overall Tgranges from -40 to 10 °C, preferably from -20 to 0 °C. In at least one embodiment, the high Tgpolymer may be present in an amount effective to allow the core-shell particles to be provided in powdered form.

[0040] The acrylic vibrational damping polymer core and the high Tgpolymer shell are preferably produced by emulsion polymerization in which the acrylic vibration dampingpolymer core is prepared first, followed by forming the high Tgpolymer shell on the acrylic vibration damping polymer core.

[0041] In other embodiments, the sound damping additive comprises the acrylic vibrational damping polymer disposed on a surface of the filler. As used herein, the term “disposed on a surface” means that the acrylic vibrational damping polymer is formed or deposited on the surface of the filler. The acrylic vibrational damping polymer may be bound, adhered or fused to the surface of the filler. For example, the acrylic vibrational damping polymer and filler particles may be combined with water to form a slurry and then dried. Heat may be applied to aid the drying process.

[0042] The sound damping additive is present in an amount ranging from 0.5 to 10 wt% relative to the total weight of the thermoplastic polyolefin 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.

[0043] The thermoplastic polyolefin resin composition may further comprise a polyolefin elastomer impact modifier. The polyolefin elastomer impact modifier may comprise an ethylene / a-olefin interpolymer, ethylene / a-olefin / nonconjugated polyene interpolymer, or a styrenic block copolymers. Examples of ethylene / a-olefin interpolymers include ethylene / Cs- C10 a-olefin interpolymers. The ethylene / a-olefin interpolymers may be a random interpolymer or multi-block interpolymer. Preferably, the ethylene / a-olefin interpolymer is selected from ethylene-propylene copolymers, ethylene-butene copolymers, ethylenehexene copolymers, ethylene-octene copolymers, and combinations thereof. More preferably, the ethylene / a-olefin interpolymer is selected from an ethylene-butene copolymer, an ethylene-octene copolymer, or a combination thereof. Ethylene / a- olefin / nonconjugated polyene interpolymers comprise, in polymerized form, ethylene, an a- olefin, and a nonconjugated polyene. The alpha-olefin may be either an aliphatic or an aromatic compound. A-olefins include, but are not limited to, a C3-C20 a-olefins, further C3- C10 a-olefins, further Cs-Cs a-olefins. A suitable, nonlimiting example of an ethylene / a- olefin / nonconjugated polyene interpolymer is EPDM (ethylene / propylene / nonconjugated diene terpolymer). Suitable examples of nonconjugated polyenes include the C4-C40 nonconjugated dienes. Nonconjugated dienes include, but are not limited to, 5-ethylidene- 2-norbornene (ENB), 5-vinyl-2-norbornene (VNB), dicyclopentadiene, 1 ,4-hexadiene, or 7- methyl-l,6-octadiene, and further from ENB, VNB, dicyclopentadiene or 1 ,4-hexadiene, and further from ENB or VNB, and further ENB. Styrenic block copolymers may include fromgreater than 1 wt% to less than 50 wt% styrene. Various olefin or diolefin (diene) comonomers are contemplated as suitable for polymerizing with the styrene. The olefin comonomer may comprise C3-C20 a-olefins. The diolefin comonomers may include various C4-C20 olefins such as 1 ,3-butadiene, 1 ,3-cyclohexadiene, isoprene, 1 ,3-pentadiene, 1 ,3- hexadiene, 2, 3-dimethyl-1 ,3-butadiene, 2-ethyl-1 ,3-butadiene, 2-methyl-1 ,3 pentadiene, 3- methyl-1 ,3-pentadiene, 4-methyl-1 ,3-pentadiene, and 2,4-hexadiene, or combinations thereof. The midblock of the styrenic block copolymer may be hydrogenated to form a saturated midblock. Examples of suitable styrenic block copolymers may include styrene- isoprene-styrene block copolymers (SIS), styrene-butadiene-styrene block copolymers (SBS), styrene-ethylene / butylene-styrene block copolymers (SEBS), styrene-isobutylene- styrene block copolymers (SIBS), styrene-ethylene-propylene-styrene block copolymers (SEPS), and combinations thereof.

[0044] The polyolefin impact modifier has a melt index (as measured in accordance with ASTM D1238, condition 190 °C / 2.16 kg) from 0.1 g / 10 min to 500 g / 10 min, or from 0.3 g / 10 min to 100 g / 10 min, or from 0.5 g / 10 min to 10 g / 10 min, or from 0.9 g / 10 min to 6 g / 10 min. The polyolefin impact modifier has a density from 0.854 g / cc to 0.905 g / cc, or from 0.854 g / cc to 0.880 g / cc, or from 0.857 g / cc to 0.875 g / cc.

[0045] The polyolefin elastomer impact modifier may be present in an amount of at least 5 wt%. Preferably, the polyolefin elastomer impact modifier is present in an amount of at least of at least 10 wt%, more preferably at least 15 wt%, and even more preferably at least 20 wt% relative to the total weight of the thermoplastic polyolefin resin composition.

[0046] The thermoplastic polyolefin resin composition may further comprise a functionalized propylene-based polymer. A "functionalized propylene-based polymer," as used herein, is a propylene-based polymer with functional groups that are anhydride, the functional groups being pendant to the polymer chain backbone. The functionalized propylene-based polymer contains from 0.1 wt% to 10 wt%, or from 0.1 wt% to 5 wt%, or from 0.3 wt% to 1 .2 wt% functional group based on the total weight of the functionalized propylene-based polymer. The functionalized propylene-based polymer has a melt index (2.16 kg, 190 °C) from 1 g / 10 min to 2000 g / 10 min, or from 10 g / 10 min to 500 g / 10 min, or from 40 g / 10 min to 150 g / 10 min. Nonlimiting examples of suitable anhydride-functionalized propylene-based polymers are prepared by grafting via a free radical mechanism, for example initiated thermally or by a peroxide, maleic anhydride to a propylene-based polymer. A nonlimiting example of suitable functionalized propylene-based polymer includes maleic anhydride (MAH)-grafted propylene homopolymer (MAH-g-PP).

[0047] The thermoplastic polyolefin resin composition may further comprise additives, such as, for example, antioxidants, pigments, thermal and / or UV stabilizers, and processing aids.

[0048] The thermoplastic resin composition may be used to produce articles, such as automotive parts. For example, the thermoplastic resin composition may be used to produce trim panels, interior and exterior door panels, airbag covers, instrument panels, and bumper fascia. By incorporating the sound damping additive of the present invention into a thermoplastic polyolefin resin composition, sound damping performance can be significantly improved, even with substantially small amounts of the sound damping additive present.ExamplesCore-Shell Sound Damping Additives

[0049] 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

[0050] 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).

[0051] 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.

[0052] The other sound damping additives, SDA 2 to SDA 5, were prepared in a similar manner.Acrylic Vibrational Damping Polymer Coated Filler

[0053] Another sound damping additive, SDA 6, was prepared by coating talc particles with an acrylic vibrational damping polymer comprising a styrenated acrylic polymer having a Tgof -23 °C. To prepared the coated filler, 450 g Jetfil 700C talc was combined with ~250g water and 91.91 g of the acrylic vibrational damping polymer (55% solids) to form a loose slurry. Slurry was then placed in an open plastic bin, covered with a Kimwipe to prevent contamination, and allowed to dry for 7 days at room temperature. Once the slurry was mostly dry, the sample was transferred onto aluminum foil and baked at 150 °C for 30 mins to drive off any remaining water. The final sample, SDA 6, was a powder composed of 90% talc and 10% acrylic polymer.Thermoplastic Formulations

[0054] Polypropylene formulations were prepared using the materials listed below in Table 2.Table 2

[0055] The above ingredients and sound damping additives were compounded according to the recipes in Table 3, where all values are weight percentages, on a ZSK-26 mm twin screw extruder and the resulting formulations were injection molded on a Toyo Si-90 electric molding machine.Table 3Damping Tests - Center Point Excitation

[0056] To explore the full mechanical damping response of the composites, the thermoplastic polyolefin 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 23 °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.Melt Flow Rate (MFR)

[0057] MFR was measured according to ASTM D1238 Method B using the pellets prepared by twin screw extrusion compounding. The test temperature was 230 °C using a 2.16 kg load.Izod Impact Testing

[0058] Notched Izod impact specimens were cut from the injection molded ASTM D638 Type I tensile bars. The specimens were notched and tested according to ASTM D256 at test temperatures of 23, 0, and -30 °C. Five specimens were measured for each sample at each temperature.Flexural Testing

[0059] Specimens for flexural testing were cut from the injection molded ASTM D638 Type I tensile bars. Flexural modulus was measured according to ASTM D790 using a crosshead speed of 0.05 in / min.Tensile Testing

[0060] Tensile properties were measured according to ASTM D638 using injection moldedASTM D638, Type 1 tensile bars. Testing was conducted at 23 °C at a test speed of 2 in / min.Multiaxial Dart Impact Testing

[0061] Multiaxial dart impact testing was conducted on an Instron CEAST 9350 Drop Tower Impact System (Dynatup) equipped with an environmental chamber and spring assist according to ASTM D3763. Four inch diameter, 0.125-inch thick injection molded discs were tested. The discs were conditioned at the test temperature for at least 4 hr prior to testing. Specimens were removed from the freezer and placed in an environmental chamber at the specified test temperature. A test speed of 6.7 m / s was used with a total test mass of 29.131 kg and 12.7 mm diameter tup. Five specimens were tested for each sample at each temperature. Samples were tested at a temperature -30 °C. The tested specimens were each characterized as ductile (no cracking or missing material from the tested part), cracked (cracking of the tested part observed, but no missing material for the tested part), or brittle (material broken off of the tested part or the part was broken into multiple separate pieces). Then the percent ductility was calculated according to the following equation:% Ductility = (Nd * 1 + Nc * 0.5) / (Nd + Nc + Nb) * 100 where Nd = number of ductile specimens; Nc = number of cracked specimens; and Nb = number of brittle specimens.Results

[0062] The results of the testing are shown below in Table 4. The data demonstrates that the inventive compositions provided good impact strength while providing significantly improved sound damping.Table 4Definitions and Usage of Terms

[0063] 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.

[0064] 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 in the 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, arange “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.

[0065] 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.

[0066] 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.

[0067] 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 to polymers prepared from more than one type of monomer). Trace amounts of impurities may be incorporated into and / or within the polymer. As used herein, the term “interpolymer” means a polymer prepared by the polymerization of at least two different types of monomers. The generic term “interpolymer” includes the term “copolymer” (which is usually employed to refer to a polymer prepared from two different monomers) as well as the term “terpolymer” (which is usually employed to refer to a polymer prepared from three different types of monomers). It also encompasses polymers made by polymerizing four or more types of monomers.

[0068] “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 thermoplastic polyolefin resin composition comprising: a thermoplastic polyolefin resin matrix; a filler; and a sound damping additive, wherein the sound damping additive comprises an acrylic vibrational damping polymer, wherein the acrylic vibrational damping polymer is not crosslinked and has a calculated glass transition temperature, Tg, ranging from -60 °C to less than 0 °C, as calculated by the Fox equation.

2. The composition of claim 1 , wherein the thermoplastic polyolefin resin matrix is selected from the group consisting of propylene-based polymer, ethylene-based polymer, and styrene-based polymer.

3. The composition of claim 2, wherein the thermoplastic polyolefin resin matrix comprises propylene-based polymer.

4. The composition of any one of the preceding claims, further comprising a polyolefin elastomer impact modifier.

5. The composition of claim 4, wherein the polyolefin elastomer impact modifier comprises an ethylene / a-olefin interpolymer.

6. The composition of claim 5, wherein the ethylene / a-olefin interpolymer comprises an ethylene / Cs-Cio a-olefin interpolymer.

7. The composition of claim 6, wherein the ethylene / a-olefin interpolymer is selected from the group consisting of ethylene-propylene copolymers, ethylene-butene copolymers, ethylene-hexene copolymers, and ethylene-octene copolymers.

8. The composition of any one of the preceding claims, wherein the acrylic vibrational damping polymer comprises a styrene / acrylic copolymer or a polyvinylacetate / acrylic copolymer.

9. The composition of any one of the preceding claims, wherein the acrylic vibrational damping polymer comprises a phosphate functionalized linear acrylic copolymer.

10. The composition of any one of the preceding claims, wherein the acrylic vibrational damping polymer forms a core with a high Tgpolymer shell formed thereon, wherein the high Tgpolymer shell has a calculated Tgof at least 50 °C.

11. The composition of claim 10, wherein the high Tgpolymer shell comprises methyl methacrylate.

12. The composition of any one of the preceding claims, wherein the sound damping additive is present in an amount of 8 wt% or less relative to the total weight of the thermoplastic polyolefin resin composition.

13. The composition of any one of the preceding claims, 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.

14. The composition of any one of the preceding claims, wherein the filler comprises talc.

15. The composition of any one of the preceding claims, wherein the filler is present in an amount ranging from 10 to 60 wt% relative to the total weight of the thermoplastic polyolefin resin composition.

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