TITLE

ENERGY ABSORBING COPOLYETHERESTER RESIN COMPOSITIONS

FIELD OF THE INVENTION

The present invention relates to the field of copolyetherester compositions for vibration damping and noise reduction applications.

BACKGROUND OF THE INVENTION

Recently, the reduction in vibration damping and noise control has become important for comfort considerations in small spaces or in private areas, such in motor vehicles. A variety of experimental techniques exists to determine damping. Measuring vibration damping of a material is typically done by measuring tangent delta, also called tan delta, tanδ, loss tangent or loss factor. This is the ratio of the loss modulus of the material to the storage modulus of the material. Loss modulus relates to the material's viscous behavior and defines the energy dissipation ability of the material. Storage modulus of the material relates to the elastic behavior of the material and defines the energy storage ability of the material.

Tanδ may be measured using a dynamic mechanical analysis test that measures the complex modulus of the material as a measure of the dissipation of external vibrational energy. Typical viscoelastic materials exhibit strong dependence on the temperature and frequency range in which they are used. Materials are categorized as being in one of the following different regions (i.e., states), depending on a temperature range and/or frequency range distinctive to the material: Glassy, Transition, Rubbery and the Flow Regions. Again, depending on the

temperature/frequency, materials can transit from one region to the next and their complex modulus will change accordingly.

For example, materials in the glassy region exhibit the highest storage modulus and consequently a very low damping level.

Materials in the transition region exhibit the most rapid change in storage modulus from the glassy to the rubbery region. Thus, it is in this region that the material possesses its highest level of damping performance. Moreover, tanδ typically shows a maximum peak in this region which can also be used to define the glass transition temperature of the material.

In the rubbery region, both the storage modulus and tanδ obtain somewhat low values and vary more slowly with changes in temperature and frequency.

In the flow region, where the material continues to soften with increasing temperature, tanδ can attain very high values.

Reducing the frequency of a typical viscoelastic material has a similar effect on the storage modulus and tanδ as increasing the

temperature of the material has on those properties, as discussed above. Thus, there exists a temperature-frequency superposition principle that can be used to convert the properties of a material from the temperature domain to the frequency domain and back again. The greater the value of tanδ, the better the vibration and noise reduction.

Absorption into the material reduces the vibrational energy transmitted, for example, to a passenger in a vehicle and the

accompanying noise. Materials that exhibit efficient vibration damping show a high conversion of vibrational energy into other forms of energy, such as heat, i.e. they have a high tanδ. Such materials have a wide range of applications where vibration and noise is of concern, such as for components of motor vehicles, commercial airplanes, aerospace, household appliances, computer hardware, recreation and sports, machines, power equipment, buildings or mechanical devices.

Various vibration damping and noise reduction materials have been described in the literature.

European Pat. No. 1212374 discloses sound damping polyester compositions comprising isoprenoid rubber modifier and a polyester selected from the group of consisting of poly(ethylene terephthalate) (PET), poly(propylene terephthalate (PPT), poly(butylene terephthalate) (PBT), poly(ethylene naphthanoate) (PEN), poly(butylene naphthanoate) (PBN) and mixtures thereof. U.S. Pat. No. 6,849,684 and InH. Pat. App. Pub. No. WO

2002/032998 disclose a molded composition of a noise damping material made of a blend of a soft thermoplastic polyether and a hard polyester resin reinforced with a fibrous or particulate filler.

Int'l. Pat. App. Pub. No. WO 2004/106052 discloses a housing suitable for sound attenuation, which comprises a plurality of rigid polymer layers separated by flexible polymer layers, wherein the flexible polymer layer is made of a thermoplastic elastomer having a polybutylene terephthalate hard segment and a glycol soft segment.

Co-pending U.S. Pat. Prov. App. 61/210053 discloses a method for vibration damping and noise reduction using a thermoplastic vulcanizate composition.

A need remains for materials having efficient vibration damping and noise reduction performance over an extended temperature range.

SUMMARY OF THE INVENTION

The inventors have surprisingly found that compositions comprising a copolyetherester resin and core-shell particles have efficient vibration damping and noise reduction behavior over an extended range of temperature and frequency.

Described herein is a use of core-shell particles for broadening the temperature range of efficient vibration dampening and/or noise reduction of a vibration damping composition comprising a copolyetherester resin.

Also described herein are uses of a vibration damping composition for vibration damping and noise reduction applications in a wide range of temperature, wherein the vibration damping composition comprises:

a) a copolyetherester resin, and

b) core-shell particles.

Further described herein are compositions comprising a

copolyetherester vulcanizate and core-shell particles.

Also described herein are multilayer structures for use in vibration damping and noise reduction applications, wherein the mulitlayer structure comprises at least one polymeric layer comprising the vibration damping compositions described herein and at least one additional layer.

Also described herein are processes for vibration damping and/or reducing noise comprising, applying to said appliance, a vibration damping composition comprising a copolyetherester resin and core-shell particles.

DETAILED DESCRIPTION

The following definitions are to be used to interpret the meaning of the terms discussed in the description and recited in the claims.

Definitions

As used herein, the term "a" refers to one as well as to at least one and is not an article that necessarily limits its referent noun to the singular.

As used herein, the terms "about" and "at or about" are intended to mean that the amount or value in question may be the value designated or some other value about the same. The phrase is intended to convey that similar values promote equivalent results or effects according to the invention.

As used herein, the term "efficient materials used to dampen noise and vibration" refer to compositions described herein and having tanδ values of at least 0.07 over a temperature range that is at least 25°C higher than that range at which an identical composition but not having core-shell particles obtains the same tanδ . For the inventions recited in the claims, tanδ values are measured using a Dynamic Mechanical Analyzer in tensile vibration mode according to ISO 6721-4 non-resonance method; measurements are done on injection molded specimens of the type ISO 527-2/5A (a length of 10 mm, a width of 4 mm and a thickness of 2 mm) at a standard frequency of 1 Hz.

As used herein, the term "highly efficient materials used to dampen noise and vibration" refer to compositions described herein, which include a copolyetherester vulcanizate, and having tanδ values of at least 0.10 over a temperature range that is at least 25°C higher than that range at which an identical composition but not having core-shell particles obtains the same tanδ. Efficient noise reduction is preferably obtained over a broad range of temperature and frequency, preferably between 1 Hz and 1600Hz. Vibration dampening efficiency is preferably observed over large temperature variations or for a wide range of applications at specific temperatures.

As used herein, the term "appliance" refers to any device in which vibration damping and/or noise reduction is desired and includes, but is not limited to, household appliances, structural components for machines, structural components for buildings, structural components for mechanical devices, and automotive components.

The vibration damping compositions described herein comprise (a) a copolyetherester resin and (b) core-shell particles.

Compositions

The copolyetherester resin is preferably present in an amount from at or about 60 to at or about 99 weight percent , more preferably from at or about 70 to at or about 90 weight percent, and still more preferably from at or about 75 to at or about 85 weight percent, the weight percent being based on the total weight of (a) + (b).

The core-shell particles are preferably present in an amount from at or about 1 to at or about 40 weight percent, more preferably from at or about 10 to at or about 30 weight percent, and still more preferably from at or about 15 to at or about 25 weight percent, the weight percent being based on the total weight of (a) + (b).

The copolyetherester resin may be a copolyetherester elastomer, a copolyetherester vulcanizate or a mixture of these.

Copolyetherester elastomers are a group of thermoplastic elastomers that have a multiplicity of recurring long-chain ester units and short-chain ester units joined head-to-tail through ester linkages, said long-chain ester units being represented by formula (A):

O O

— OGO CRC

(A) and said short-chain ester units being represented by formula (B):

O O

— ODO CRC

(B)

wherein

G is a divalent radical remaining after the removal of terminal hydroxyl groups from poly(alkylene oxide)glycols having a number average molecular weight of between about 400 and about 6000, or preferably between about 400 and about 3000;

R is a divalent radical remaining after removal of carboxyl groups from a dicarboxylic acid having a molecular weight of less than about 300;

D is a divalent radical remaining after removal of hydroxyl groups from a diol having a molecular weight less than about 250.

As used herein, the term "long-chain ester units" as applied to units in a polymer chain refers to the reaction product of a long-chain glycol with a dicarboxylic acid. Suitable long-chain glycols are poly(alkylene oxide) glycols having terminal (or as nearly terminal as possible) hydroxy groups and having a number average molecular weight of from about 400 to about 6000, and preferably from about 600 to about 3000. Preferred poly(alkylene oxide) glycols include poly(tetramethylene oxide) glycol, poly(thmethylene oxide) glycol, poly(propylene oxide) glycol, poly(ethylene oxide) glycol, copolymer glycols of these alkylene oxides, and block copolymers such as ethylene oxide-capped poly(propylene oxide) glycol. Mixtures of two or more of these glycols can be used.

As used herein, the term "short-chain ester units" as applied to units in a polymer chain of the copolyetheresters refers to low molecular weight compounds or polymer chain units having molecular weights less than about 550. They are made by reacting a low molecular weight diol or a mixture of diols (molecular weight below about 250) with a dicarboxylic acid to form ester units represented by Formula (B) above.

Included among the low molecular weight diols which react to form short- chain ester units suitable for use for preparing copolyetheresters are acyclic, alicyclic and aromatic dihydroxy compounds. Preferred compounds are diols with about 2-15 carbon atoms such as ethylene, propylene, isobutylene, tetramethylene, 1 ,4-pentamethylene, 2,2- dimethylthmethylene, hexamethylene and decamethylene glycols, dihydroxycyclohexane, cyclohexane dimethanol, resorcinol, hydroquinone, 1 ,5-dihydroxynaphthalene, etc. Especially preferred diols are aliphatic diols containing 2-8 carbon atoms, and a more preferred diol is 1 ,4- butanediol. Included among the bisphenols which can be used are bis(p- hydroxy)diphenyl, bis(p-hydroxyphenyl)methane, and bis(p- hydroxyphenyl)propane. Equivalent ester-forming derivatives of diols are also useful (e.g., ethylene oxide or ethylene carbonate can be used in place of ethylene glycol or resorcinol diacetate can be used in place of resorcinol).

As used herein, the term "diols" includes equivalent ester-forming derivatives such as those mentioned. However, any molecular weight requirements refer to the corresponding diols, not their derivatives.

Dicarboxylic acids that can react with the foregoing long-chain glycols and low molecular weight diols to produce the copolyetheresters are aliphatic, cycloaliphatic or aromatic dicarboxylic acids of a low molecular weight, i.e., having a molecular weight of less than about 300. The term "dicarboxylic acids" as used herein includes functional equivalents of dicarboxylic acids that have two carboxyl functional groups that perform substantially like dicarboxylic acids in reaction with glycols and diols in forming

copolyetherester polymers. These equivalents include esters and ester- forming derivatives such as acid halides and anhydrides. The molecular weight requirement pertains to the acid and not to its equivalent ester or ester-forming derivative.

Thus, an ester of a dicarboxylic acid having a molecular weight greater than 300 or a functional equivalent of a dicarboxylic acid having a molecular weight greater than 300 are included provided the

corresponding acid has a molecular weight below about 300. The dicarboxylic acids can contain any substituent groups or combinations that do not substantially interfere with the copolyetherester polymer formation and use of the polymer in the vibration damping compositions of this invention.

As used herein, the term "aliphatic dicarboxylic acids" refers to carboxylic acids having two carboxyl groups each attached to a saturated carbon atom. If the carbon atom to which the carboxyl group is attached is saturated and is in a ring, the acid is cycloaliphatic. Aliphatic or

cycloaliphatic acids having conjugated unsaturation often cannot be used because of homopolymerization. However, some unsaturated acids, such as maleic acid, can be used.

As used herein, the term "aromatic dicarboxylic acids" refer to dicarboxylic acids having two carboxyl groups each attached to a carbon atom in a carbocyclic aromatic ring structure. It is not necessary that both functional carboxyl groups be attached to the same aromatic ring and where more than one ring is present, they can be joined by aliphatic or aromatic divalent radicals or divalent radicals such as -O- or -SO ₂ -. Representative useful aliphatic and cycloaliphatic acids that can be used include sebacic acid; 1 ,3-cyclohexane dicarboxylic acid; 1 ,4-cyclohexane dicarboxylic acid; adipic acid; glutahc acid; 4-cyclohexane-1 ,2-dicarboxylic acid; 2-ethylsuberic acid; cyclopentanedicarboxylic acid decahydro-1 ,5- naphthylene dicarboxylic acid; 4,4'-bicyclohexyl dicarboxylic acid;

decahydro-2,6-naphthylene dicarboxylic acid; 4,4'- methylenebis(cyclohexyl) carboxylic acid; and 3,4-furan dicarboxylic acid. Preferred acids are cyclohexane-dicarboxylic acids and adipic acid.

Representative aromatic dicarboxylic acids include phthalic, terephthalic and isophthalic acids; bibenzoic acid; substituted dicarboxy compounds with two benzene nuclei such as bis(p- carboxyphenyl)methane; p-oxy-1 ,5-naphthalene dicarboxylic acid; 2,6- naphthalene dicarboxylic acid; 2,7-naphthalene dicarboxylic acid; 4,4'- sulfonyl dibenzoic acid and C1-C12 alkyl and ring substitution derivatives thereof, such as halo, alkoxy, and aryl derivatives. Hydroxyl acids such as p-(beta-hydroxyethoxy)benzoic acid can also be used provided an aromatic dicarboxylic acid is also used. Aromatic dicarboxylic acids are a preferred class for preparing the copolyetherester elastomer useful for this invention. Among the aromatic acids, those with 8-16 carbon atoms are preferred, particularly terephthalic acid alone or with a mixture of phthalic and/or isophthalic acids.

The copolyetherester elastomer preferably comprises from at or about 15 to at or about 99 weight percent short-chain ester units corresponding to Formula (B) above, the remainder being long-chain ester units

corresponding to Formula (A) above. More preferably, the

copolyetherester elastomer comprise from at or about 20 to at or about 95 weight percent, and even more preferably from at or about 50 to at or about 90 weight percent short-chain ester units, where the remainder is long-chain ester units. More preferably, at least about 70% of the groups represented by R in Formulae (A) and (B) above are 1 ,4-phenylene radicals and at least about 70% of the groups represented by D in Formula (B) above are 1 ,4-butylene radicals and the sum of the percentages of R groups which are not 1 ,4-phenylene radicals and D groups that are not 1 ,4-butylene radicals does not exceed 30%. If a second dicarboxylic acid is used to make the copolyetherester, isophthalic acid is preferred and if a second low molecular weight diol is used, ethylene glycol, 1 ,3-propanediol, cyclohexanedimethanol, or hexamethylene glycol are preferred.

A blend or mixture of two or more copolyetherester elastomers can be used. The copolyetherester elastomers used in the blend need not on an individual basis come within the values disclosed hereinbefore for the elastomers. However, the blend of two or more copolyetherester elastomers must conform to the values described herein for the

copolyetheresters on a weighted average basis. For example, in a mixture that contains equal amounts of two copolyetherester elastomers, one copolyetherester elastomer can contain 60 weight percent short-chain ester units and the other resin can contain 30 weight percent short-chain ester units for a weighted average of 45 weight percent short-chain ester units.

Preferred copolyetherester elastomers include, but are not limited to, copolyetherester elastomers prepared from monomers comprising (1 ) poly(tetramethylene oxide) glycol; (2) a dicarboxylic acid selected from isophthalic acid, terephthalic acid and mixtures thereof; and (3) a diol selected from 1 ,4-butanediol, 1 ,3-propanediol and mixtures thereof, or from monomers comprising (1 ) poly(trimethylene oxide) glycol; (2) a dicarboxylic acid selected from isophthalic acid, terephthalic acid and mixtures thereof; and (3); and (3) a diol selected 1 ,4-butanediol, 1 ,3- propanediol and mixtures thereof, or from monomers comprising ethylene oxide-capped polypropylene oxide) glycol; (2) dicarboxylic acid selected from isophthalic acid, terephthalic acid and mixtures thereof; and (3) a diol selected 1 ,4-butanediol, 1 ,3-propanediol and mixtures thereof.

Preferably, the copolyetherester elastomers for use in the vibration damping compositions described herein are prepared from esters or mixtures of esters of terephthalic acid and/or isophthalic acid, 1 ,4- butanediol and poly(tetramethylene ether)glycol or poly(thmethylene ether) glycol or ethylene oxide-capped polypropylene oxide glycol, or are prepared from esters of terephthalic acid, e.g. dimethylterephthalate, 1 ,4- butanediol and poly(ethylene oxide)glycol. More preferably, the

copolyetheresters are prepared from esters of terephthalic acid, e.g.

dimethylterephthalate, 1 ,4-butanediol and poly(tetramethylene

ether)glycol.

Examples of suitable copolyetherester elastomers are commercially available under the trademark Hytrel ^® from E. I. du Pont de Nemours and Company, Wilmington, Delaware. Copolvetherester Vulcan izate

As mentioned above, the copolyetherester resin may be a copolyetherester vulcanizate. Copolyetherester vulcanizates are blends consisting of a continuous thermoplastic phase with a phase of vulcanized elastomer dispersed therein. Vulcanizate and the phrase "vulcanizate rubber" as used herein are intended to be generic to the cured or partially cured, cross-linked or cross-linkable rubber as well as curable precursors of cross-linked rubber and as such include elastomers, gum rubbers and so-called soft vulcanizates as commonly recognized in the art. Copolyetherester vulcanizates combine many desirable

characteristics of cross-linked rubbers with some characteristics of thermoplastic elastomers. Copolyetherester vulcanizates can be processed in many ways like a thermoplastic, but which has the

characteristics of a cross-linked rubber. In contrast to conventional vulcanizates thermosets, copolyetherester vulcanizates can be injection moulded, or extruded without requiring further curing. Copolyetherester vulcanizates for use in the present inventions are described in U.S. Pat. No. 7074857, Pat. App. Pub. No. 2005/084694 and Int'l. Pat. App. Pub. No. WO 2004/029155, which are hereby incorporated by reference herein.

The copolyetherester vulcanizate for use in the compositions described herein preferably comprises i) from at or about 15 to at or about 75 weight percent, preferably from at or about 15 to at or about 60 weight percent, of a continuous phase comprising the copolyetherester resin which is a copolyetherester elastomer described above, and ii) from at or about 25 to at or about 85 weight percent, preferably from at or about 40 to at or about 85 weight percent , of at least one poly(meth)acrylate or polyethylene/(meth)acrylate rubber that forms a dispersed phase, wherein the rubber is dynamically cross-linked after dispersion in the continuous phase with at least one peroxide free-radical initiator and at least one organic multiolefinic co-agent, the weight percent being based on the total weight of the copolyetherester vulcanizate (i+ii).

As used herein, the term "(meth)acrylic acid" refers to methacrylic acid and/or acrylic acid; the term "(meth)acrylate" refers to methacrylate and/or acrylate and the term "poly(meth)acrylate refers to polymers derived from the polymerization of methacrylate and/or acrylate

monomers.

As used herein, the term "organic multiolefinic co-agent" refers to mean organic co-agents that contain two or more unsaturated double bonds.

The acrylate rubber may be prepared by copolymerizing one or more (meth)acrylate monomers with one or more olefins. A preferred olefin is ethylene. As used herein, the term "cross-linked acrylate rubber" refers to component (ii). Preferably, the acrylate rubber includes poly(alkyl (meth)acrylate) rubbers, ethylene/alkyl (meth)acrylate copolymer rubber and poly(perfluoroalkyl (meth)acrylate) rubber, and are more preferably an ethylene/alkyl (meth)acrylate copolymer rubbers where the alkyl group has from 1 to 4 carbons. Preferred ethylene/alkyl (meth)acrylate copolymers are those derived from less than about 80 weight percent of ethylene and more than about 20 weight percent alkyl (meth)acrylate. The acrylate rubbers may optionally comprise additional repeat units derived from one or more functionalized comonomers, such as (meth)acrylate glycidyl esters (such as glycidyl methacrylate), maleic acid, or other comonomer having one or more reactive groups including acid, hydroxyl, epoxy, isocyanates, amine, oxazoline, chloroacetate, or diene functionality. The acrylate rubbers may also be made from more than two (meth)acrylate monomers. Examples are acrylate rubbers made by polymerizing ethylene, methyl acrylate, and a second acrylate (such as butyl acrylate). Suitable free-radical initiators include but are not limited to 2,5-dimethyl- 2,5-di-(f-butylperoxy)hexyne-3; f-butyl peroxybenzoate; 2,5-dimethyl-2,5- di-(f-butylperoxy)-2,5-dimethylhexane; dicumyl peroxide; α,α-bis(f- butylperoxy)-2,5-dimethylhexane; and the like.

Suitable organic multiolefinic co-agents include, but are not limited to, diethylene glycol diacrylate; diethylene glycol dimethacrylate; N,N'-m- phenylene dimaleimide; triallylisocyanurate; thmethylolpropane

trimethacrylate; tetraallyloxyethane; triallyl cyanurate; tetramethylene diacrylate; polyethylene glycol dimethacrylate; and the like.

Making the Copolvetherester Vulcanizate

The copolyetherester vulcanizate described herein may be prepared using processes such as those described in Intl. Pat. App. Pub. No. WO

2004/029155. The actual mixing of components and subsequent dynamic cross-linking may be performed either in a batch mode or a continuous mode using conventional melt blending equipment. An example is a process comprising the steps of: (a) adding and admixing a cross-linkable poly(meth)acrylate or

polyethylene/(meth)acrylate vulcanizate rubber, at least one peroxide free- radical initiator and at least one organic multiolefinic co-agent in a melt extruder or melt blender at a temperature insufficient to promote significant cross-linking;

(b) adding a copolyetherester elastomer to the melt extruder or melt blender and admixing the copolyetherester resin with the cross-linkable poly(meth)acrylate or polyethylene/(meth)acrylate vulcanizate rubber prior to cross-linking;

(c) further mixing the cross-linkable poly(meth)acrylate or

polyethylene/(meth)acrylate vulcanizate rubber with the at least one peroxide free radical initiator and the at least one organic multiolefinic co- agent with the copolyetherester resin at conditions and temperature sufficient to cross-link the cross-linkable poly(meth)acrylate or

polyethylene/(meth)acrylate vulcanizate rubber; and

(d) recovering the copolyetherester vulcanizate comprising the

copolyetherester elastomer as a continuous phase and of the

poly(meth)acrylate or polyethylene/(meth)acrylate vulcanizate rubber cross-linked with the at least one peroxide free radical initiator and the at least one organic multiolefinic co-agent as a disperse phase.

Suitable examples of copolyetherester vulcanizate for use in the present invention are commercially available under the trademark

DuPont™ ETPV from E. I. du Pont de Nemours and Company,

Wilmington, Delaware.

Dependening on the end-use application, the copolyetherester resin may be a copolyetherester elastomer, a copolyetherester vulcanizate or a mixture thereof. Copolyetherester vulcanizates are typically used in applications where oil and/or heat (130 ^° C - 170 ^° C) resistance are required. This material is proposed as a replacement of cross-linked high

performance rubber by a thermoplastic material that has low hardness in the Shore A range, that can be processed by standard thermoplastic processing techniques therefore bringing significant cost savings versus cross-linked rubber, that has excellent oil and heat resistance and recyclability.

Core-shell Particles

Examples of core-shell particles are described in U.S. Pat. Nos.

3,426,101 , 6,331 ,580, 4,200,567, 4,260,693 and 4,096,202. As used herein, "core-shell particles" refer to particles having an encapsulated elastomeric/rubbery core on which a thermoplastic shell is grafted.

The core-shell particles comprise:

i) a core comprising an elastomeric material with a glass transition temperature equal to or lower than the glass transition temperature of the copolyetherester resin, and

ii) a shell comprising a rigid polymer or copolymer having a glass transition temperature of greater than 50 ^° C and preferably greater than 100 ^° C.

The core-shell particles may comprise one or more additional layers, which additional layers are different from the core i) and the shell ii).

The elastomeric material used for the core of the core-shell particles is preferably selected from acrylic-based rubber elastomeric materials, copolymers containing a diolefin monomer based rubber elastomeric materials and mixtures thereof. More preferably, the elastomeric material used for the core are preferably selected from acrylic- based rubber elastomeric materials, butadiene-based rubber elastomeric materials and mixtures thereof.

Preferred examples of acrylic-based rubber elastomeric materials for the core are acrylic polymers derived from a C4 to C12 acrylates.

Thermoplastic acrylic polymers are made by polymerizing acrylic acid, acrylate esters (e.g. methyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, n-hexyl acrylate, and n-octyl acrylate), methacrylic acid, and methacrylate esters (e.g. methyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate (BA), isobutyl methacrylate, n-amyl methacrylate, n-octyl methacrylate, glycidyl methacrylate (GMA) and the like). Copolymers derived from two or more of the forgoing types of monomers may also be used, as well as copolymers made by polymerizing one or more of the forgoing types of monomers with styrene, acrylonitrile, butadiene, isoprene, and the like. Preferred monomers for the preparation of the thermoplastic acrylic polymer are methyl acrylate, n- propyl acrylate, isopropyl acrylate, n-butyl acrylate, n-hexyl acrylate, and n-octyl acrylate.

For core-shell particles in which the core is an acrylic-based rubber elastomeric material, the shell preferably comprises a vinyl aromatic compound and/or a vinyl cyanide and/or an alkyl (meth)acrylate and/or (meth)acrylic acid such as for example methyl methacrylate (MMA), a polyalkyl methacrylate (like for example polymethyl methacrylate, PMMA) and a styrene acrylonitrile copolymer.

Particularly preferred examples of core-shell particles have a core made of poly(butyl acrylate) and a shell made of poly(methyl

methacrylate). Suitable core-shell particles having a core made of a acrylic-based rubber elastomeric material are commercially available from Rohm and Haas, Philadelphia, PA under the trademark Paraloid ^® EXL- 3300 or from Arkema, Colombes, France under the trademark

Durastrength ^® 440.

Preferred examples of copolymers containing a diolefin monomer based rubber elastomeric materials for the core of the core-shell particles indue butadiene-based rubber elastomeric materials. When the core of the core-shell particles is made of butadiene-based rubber elastomeric materials, the core is preferably made of a polybutadiene, a polybutadiene copolymer rubber or a mixture of these. When the core of the core-shell particles is made of butadiene-based rubber elastomeric materials, the shell of the core-shell particles preferably comprises a vinyl aromatic compound and/or a vinyl cyanide and/or an alkyl (meth)acrylate and/or (meth)acrylic acid such as for example methyl methacrylate (MMA), a polyalkyl methacrylate (like for example polymethyl methacrylate, PMMA) and a styrene copolymer.

A particularly preferred example of core-shell particles are those having a core made of polybutadiene or butadiene-styrene copolymer and a shell made of poly(methyl methacrylate). Suitable core-shell particles having a core made of butadiene-based rubber elastomeric materials are commercially available from Rohm and Haas, Philadelphia, PA under the trademark Paraloid ^® EXL-3600 and BLX-3670 or from Arkema, Colombes, France under the trademark Clearstrength ^® E-920 and E-922.

The shell of core-shell particles can be coated with a low surface energy substrate like for example silicone, fluorine and the like to improve the compatibilization with other polymers or ingredients of the overall polymeric composition so as to provide a good dispersion of the core-shell particles within the overall polymeric composition.

The morphology of the core-shell particles is not limited. Regular structures wherein the core is centered in the particles or irregular core- shell particles wherein the core is not a circle (roundness) and/or not at the center of core-shell particles (eccentricity) can be used.

The core-shell particles can have various average particle sizes. The preferred range of average particle sizes is from at or about 1 to at or about 5000 nm and more preferably from at or about 50 to at or about 1500 nm, however larger particles, or mixtures of small and large particles, may also be used. The average particule size is measured by the technique of laser diffraction from a suspension of particles in a solvent using a particle size analyzer, Mastersizer 2000 from Malvern. This test method meets the requirements set forth in ISO 13320.

Heat Stabilizers and/or Antioxidants

The vibration damping compositions described herein may further comprise one or more heat stabilizer and/or antioxidants. Examples of suitable heat stabilizers and/or antioxidants include diphenylamines, amides, thioesters, phenolic antioxidants, and phosphites. When used, the one or more heat stabilizers and/or antioxidants are preferably present in at or about 0.01 to at or about 5 weight percent, or more preferably in at or about 0.01 to at or about 2 weight percent, the weight percent being based on the total weight of vibration damping composition. The vibration damping compositions described herein may further comprise one or more colorants. When used, the one or more colorants are preferably present in at or about 0.1 to at or about 5 weight percent, the weight percent being based on the total weight of the vibration damping composition.

Other Additives

The vibration damping compositions described herein may further include modifiers and other ingredients, including, without limitation, lubricants, fillers and reinforcing agents, flame retardants, impact modifiers, flow enhancing additives, antistatic agents, crystallization promoting agents, conductive additives, viscosity modifiers, nucleating agents, plasticizers, mold release agents, scratch and mar modifiers, drip suppressants, adhesion modifiers and other processing aids known in the polymer compounding art.

Fillers, modifiers and other ingredients described above may be present in the vibration damping composition in amounts and in forms well known in the art, including in the form of so-called nano-materials where at least one of the dimensions of the particles is in the range of 1 to 1000 nm.

Making the Vibration Damping Compositions

The vibration damping compositions described herein are melt- mixed blends, wherein all of the polymeric components are well- dispersed within each other and all of the non-polymeric ingredients are well-dispersed in and bound by the polymer matrix, such that the blend forms a unified whole. Any melt-mixing method may be used to

combine the polymeric components and non-polymeric ingredients of the present invention. For example, the polymeric components and non- polymeric ingredients may be added to a melt mixer, such as, for example, a single or twin-screw extruder; a blender; a single or twin- screw kneader; or a Banbury mixer, either all at once through a single step addition, or in a stepwise fashion, and then melt-mixed. When adding the polymeric components and non-polymeric ingredients in a stepwise fashion, part of the polymeric components and/or non- polymeric ingredients are first added and melt-mixed with the remaining polymeric components and non-polymeric ingredients being

subsequently added and further melt-mixed until a well-mixed

composition is obtained. When long fillers such as for example long glass fibers are used in the vibration dampening composition, pultrusion may be used to prepare a reinforced composition.

Articles and Multilayer Structures

Also described herein are articles made of the vibration damping compositions as well as methods for making them by shaping the vibration damping compositions. As used herein, the term "shaping" refers to any shaping technique, such as extrusion or molding, which includes injection molding, compression molding or blow molding.

In addition, the articles comprising the vibration damping

compositions described herein may comprise multilayer structures that may damp vibration and reduce noise. These multilayer structures comprise at least one polymeric layer comprising the vibration damping composition and at least one additional layer that does not comprise the vibration damping composition. The at least one polymeric layer comprising the vibration damping composition may be situated as an inner layer sandwiched either between other polymeric layers or between additional layers not comprising the vibration damping composition or sandwiched between a mixture of these layers, or as an outer layer adjacent to at least one additional layer.

The layer(s) not containing the vibration damping composition may be made from, for example, polymers, adhesive layers, metal, glass, wood, fiber, fabric, metal oxide, stone and concrete. Examples of polymers used for the additional layer(s) include thermoplastic polymers, thermoplastic elastomers, thermoplastic copolyesters or polymers exhibiting high stiffness and/or high temperature resistance.

In a preferred structure for automotive use, the multilayer structure consists of two layers, a polymeric layer comprising the vibration damping composition described herein and an outer layer not comprising the vibration damping composition and exposed to the outside surroundings.

Preferably, the outer layer for automotive use is made of a metal preferably selected selected from aluminum, aluminum alloys, copper, bronze, steel, stainless steel, chrome or titanium and mixtures of these. One or more adhesive layers may be added between the different layers.

The thickness of the polymeric layer comprising the composition described herein for use in the 2-layer structure is preferably at least about 10 μm, and more preferably between 200 and 500 μm.

Additionally, the multilayer structures described herein may further comprise a printable and/or colorable layer that is preferably positioned on the outermost additional layer surface of the multilayer structure. The printable and/or colorable layer may be a polymeric film, paper, board, and combinations of these.

Moreover, the multilayer structure may comprise at least two additional layers not containing the vibration damping composition, which sandwich the at least one polymeric layer comprising the vibration damping composition. The thickness of the at least one polymeric layer for use in the sandwich structure is preferably at least about 10 μm, more preferably between 25 and 500 μm and still more preferably between 25 and 250 μm. Preferably, the at least two additional layers sandwiching the at least one polymeric layer are made of a metal and more preferably a metal selected from aluminum, aluminum alloys, copper, bronze, steel, stainless steel, chrome or titanium and mixtures of these. These metals may also be surface treated or have thereon surface conversion coatings. The additional layers on each side of the polymeric layer may be formed of the same metal or of different metals and can have the same or different thicknesses. The choice of metal of the at least two additional outer layers outer layer is not critical and the it is within the skill of the art to choose metals depending on the use of the structure.

The multilayer structure comprising at least one additional layer made of metal and at least one polymeric layer comprising the vibration damping composition may be manufactured by a single process, such as laminating or extrusion coating the vibration damping composition onto the metal layer. Alternatively, these multilayer structures may be

manufactured by using pressure and heat to bind a polymeric layer comprising the vibration damping composition and a metal layer. If one or more layers are needed between the polymeric layer comprising the compositions described herein and the additional metal layer, the multilayer structure may be manufactured by a single process such as co- extrusion coating the layer and the polymeric material onto the metal layer.

In addition, a film containing at least one layer of the vibration damping composition described herein may be produced via cast-film mono- or multi-layer extrusion, or blown film mono- or multi-layer extrusion processes and the surface of the film treated so as to promote adhesion to the additional layer made of metal or to increase surface smoothness. Uses and Processes of Using the Compositions, Articles and MultiLaver Structures Described Herein

The articles and multilayer structures made of the vibration damping compositions described herein may be used in applications where vibration damping and noise reduction are desired. Such applications include household appliances, such as washers, dryers, refrigerators, heating-ventilation-air conditioning appliances, etc.; components for electronic devices, such as computers; components for building or mechanical devices, such as fans, switches and compressors.

Such applications also include motorized vehicles in which the article may dampen the vibration and noise arising from the motor, the engine, climate control systems, the road or environment inputs, the rolling noise of car tires or from any other noise emitters. Examples of vibration damping and noise reduction components of vehicles are body panels, dashboards, engine covers, rocker panels or air filter covers.

As mentioned above, the vibration damping compositions described herein have "efficient" vibration damping and noise reduction performance over a greater temperature range when compared with that of

compositions not having core-shell particles. As used herein, the term "efficient" vibration damping and noise reduction means that the vibration damping compositions described herein exhibit tanδ of at least 0.07 over a temperature range preferably at least 25 ⁰ C greater than that range at which control compositions not having core-shell particles exhibit the same tanδ.

The term "efficient" vibration damping and noise reduction also means that the vibration damping compositions described herein that comprise a copolyetherester vulcanizate exhibit tanδ of at least 0.10 over a temperature range preferably at least 25 ⁰ C larger than that at which control compositions comprising a copolyether vulcanizate but not having core-shell particles exhibit the same same tanδ.

Tanδ is measured using a Dynamic Mechanical Analyzer in tensile vibration mode according to ISO 6721 -4 non-resonance method and measurements are done on injection molded specimens of the type ISO 527-2/5A (a length of 10 mm, a width of 4 mm and a thickness of 2 mm) at a standard frequency of 1 Hz.

EXAMPLES

The Examples below provide greater detail for the compositions, uses and processes described herein.

Materials

The following materials were used for preparing the vibration damping compositions used for the present invention and comparative examples.

Copolyetherester N°1

A copolyetherester elastomer containing about 35.3 weight percent of poly(tetramethylene oxide) having an average molecular weight of about 1000 g/mol as polyether block segments, the weight percentage being based on the total weight of the copolyetherester elastomer. The short chain ester units were polybutylene terephthalate segments. Copolyetherester N°2

A copolyetherester elastomer containing about 15.8 weight percent of poly(tetramethylene oxide) having an average molecular weight of about 1000 g/mol as polyether block segments, the weight percent being based on the total weight of the copolyetherester elastomer. The short chain ester units were polybutylene terephthalate segments.

Copolyetherester N°3

A copolyetherester vulcanizate blend containing about 48.1 weight percent of the copolyetherester N ^° 1 and a rubber, the weight percent being based on the total weight of the vulcanizate blend. The rubber was an ethylene methyl-acrylate copolymer comprising 62 weight percent of methyl- acrylate, the weight percent being based on the total weight of the copolymer. The rubber was crosslinked using about 3.3 weight percent of 2,5-dimethyl-2,5-di-(t-butylperoxy) hexyne-3 (DYBP) as peroxide curative and about 4.5 weight percent of organic multiolefinic co-agent diethylene glycol dimethacrylate (DEGDM), the weight percent being based on the total weight of the rubber. Copolyetherester N°4

A copolyetherester vulcanizate blend containing about 50.2 weight percent of copolyetherester N ^° 2 and a rubber, the weight percent being based on the total weight of the vulcanizate blend. The rubber was an ethylene methyl-acrylate copolymer comprising 62 weight percent of methyl- acrylate, the weight percent being based on the total weight of the copolymer. The rubber was crosslinked using about 2.7 weight percent of 2,5-dimethyl-2,5-di-(t-butylperoxy) hexyne-3 (DYBP) as peroxide curative and about 4.6 weight percent of organic multiolefinic co-agent diethylene glycol dimethacrylate (DEGDM) cure system (dynamic vulcanization), the weight percent being based on the total weight of the rubber.

As required for the manufacturing process of the copolyetherester resins (N ^° 1 to N ^° 4) and well-known to those skilled in the art, copolyetheresters (N ^° 1 , N ^° 2) and copolyetherester vulcanizates (N ^° 3, N ^° 4) may contain up to 2 weight percent of suitable heat stabilizers and/or antioxidants including diphenylamines, amides, thioesters, phenolic antioxidants and phosphites. These stabilizers/antioxidants may be introduced directly or as a suitable heat stabilized concentrate during the manufacturing process and/or may be melt mixed with the thermoplastic vulcanizates. The thermoplastic vulcanizate may also contain up to 3 weight percent of a suitable color concentrate.

Core-shell particles 1 : core-shell particles having a rubbery butyl-acrylate core (T ₉ = -45 ^° C) onto which methyl methacrylate is grafted; and having an average particle size of about 300 nm. This product is commercially available under the tradename Paraloid® EXL-3300 and is supplied by

Rohm and Haas, Philadelphia, PA.

Core-shell particles 2: core-shell particles having a rubbery styrene- butadiene copolymer core (T ₉ = -80 ^° C) onto which methyl methacrylate is grafted; and having an average particle size of 100-300 nm. This product is commercially available under the tradename Paraloid® EXL-3600 and is supplied by Rohm and Haas, Philadelphia, PA. Core-shell particles 3: core-shell particles having a rubbery styrene- butadiene copolymer core (T ₉ = -80 ^° C) onto which methyl methacrylate is grafted; and having an average particle size of 300-1500 nm. This product is commercially available under the tradename Paraloid® BLX-3670 and is supplied by Rohm and Haas, Philadelphia, PA.

The copolyetherester N ^° 3 and N ^° 4 (copolyetherester vulcanizates) were prepared according to the process described in the detailed description and in Intl. Patent Appln. Publn. No. WO 2004/029155.

Compositions of the Examples (abbreviated as "E" in the Tables) and Comparative Examples (abbreviated as "C" in the Tables) were melt- mixed blends; samples were prepared in a twin-screw extruder having barrel temperatures set at about 220 ^° C to about 240 ^° C. Ingredients were blended together and fed through the main feeder into the barrel furthest from the die. Measurements

The melting temperature of the samples in the form of pellets was measured according to ISO 11357-3, DSC, 2 ^nd heating cycle at 10°C/min heating and cooling rates and all experimental conditions given in the norm except that holding time was 10 minutes at maximum temperature of 250 ^° C and one minute at minimum temperature of 40 ^° C.

The viscoelastic material properties, including the dynamic modulus and the tangent delta (tanδ) were measured using a Dynamic Mechanical Analyzer (DMA) (Metravib VA4000) in tensile vibration mode according to ISO 6721 -4 non-resonance method. The tests were done on injection molded specimens of the type ISO 527-2/5A (i.e. a length of 10 mm, a width of 3.8-4.1 mm and a thickness of 2.1 -2.5 mm, the variation of the value of the width and the thickness being from one test specimen to another one). Test specimens were conditioned at 23 ^° C for at least 24 hours before the measurements. The tests were done at a standard frequency of 1 Hz and by continuously increasing the temperature from - 100 ^° C to +200 ^° C at a heating rate of 2 ^° C/min.

Results for compositions comprising a copolyetherester elastomer are given in Table 2. Results for compositions comprising a copolyetherester vulcanizate are given in Table 3.

Table 1 : Compositions comprising a copolyetherester elastomer according to the present invention (E1-E10) and comparative ones (C1 -C4).

Ingredient quantities are given in weight percent, based on the total weight of the composition.

Table 2: Results of the compositions comprising a copolyetherester elastomer according to the present invention (E1 -E4) and comparative ones (C1 -C2).

Table 3: Results of the compositions comprising a copolyetherester vulcanizate according to the present invention (E5-E10) and comparative ones (C3-C4).

As shown in Table 2, a copolyetherester elastomer without core- shell particles (C1) exhibited a reasonable loss factor (tanδ > 0.07) only in a narrow range of temperature (from -52 to +14 ^° C) and the range was shifted to low temperatures, making it unsuitable for high temperature uses. In contrast, the same copolyetherester elastomer with core-shell particles (E1-E2) exhibited to a significant increase of the temperature range for efficient vibration dampening and noise reduction (tanδ > 0.07). Indeed, the compositions comprising a copolyetherester elastomer and core-shell particles for use in the invention (E1 and E2) exhibited a reasonable loss factor (tanδ > 0.07) in a temperature range that was at least 70 ^° C broader than the comparative composition (C1) (a broadening of the temperature range of 96 ^° C and 70 ^° C, respectively for E1 and E2). The copolyetherester elastomer without core-shell particles (C2) exhibited a reasonable loss factor (tanδ > 0.07) only in a narrow range of

temperature (from -2 to +58 ^° C).

In contrast, the compostion comprising a copolyetherester elastomer with core-shell particles for use in the present invention (E3 and E4) exhibited a sufficiently high loss factor (tanδ > 0.07) over a

significantly broader temperature range. Compositions for use in the present invention (E3-E4) exhibited a loss factor (tanδ > 0.07) in a temperature range that was at least 26 ^° C broader than the comparative composition (C2) (a broadening of the temperature range of 42 ^° C and 26 ^° C, respectively for E3 and E4).

As shown in Tables 2 and 3, when the copolyetherester resin was a copolyetherester vulcanizate, the vibration damping performance of the material was improved compared to compositions comprising a

copolyetherester elastomer (C3 vs C1 and C4 vs C2) not only in terms of tanδ values but also in terms of temperature ranges of efficient vibration dampening and noise reduction. Moreover, the increase of the

temperature range of efficient vibration dampening and noise reduction (tanδ > 0.07) obtained by using the compositions comprising a

copolyetherester vulcanizate and core-shell particles for use in the present invention (E5-E10) was even more pronounced. As shown in Table 3 and in analogy with the compositions comprising a copolyetherester elastomer and core-shell particles for use in the present invention, the compositions for use in the present invention comprising a copolyetherester vulcanizate and core-shell particles (E5- E10) exhibited a reasonable loss factor (tanδ > 0.07) in a significantly broader temperature range than the copolyetherester vulcanizate without core-shell particles (C3-C4), which range of temperature was extended to high temperatures. Such an effect in high temperature is advantageous for high performance demanding applications.

Surprisingly, the increase of the temperature range of highly efficient vibration dampening and noise reduction (tanδ > 0.10) is even more pronounced than the increase of the temperature range of efficient vibration dampening and noise reduction (tanδ > 0.07) for the

compositions for use in the present invention comprising a

copolyetherester vulcanizate and core-shell particles (E5-E10), i.e. the broadening of the temperature range wherein vibration dampening and noise reduction is efficient is even more pronounced when higher performance is required (tanδ > 0.10).

Compositions for use in the present invention (E5-E7) exhibited a high loss factor (tanδ > 0.10) in a temperature range that was at least 43 ^° C broader than the comparative composition (C3) (an increase of the termperature range of 73 ^° C, 46 ^° C and 40 ^° C, respectively for E5, E6 and E7). Compositions for use in the present invention (E8-E10) exhibited a high loss factor (tanδ > 0.10) in a temperature range that was at least 26 ^° C broader than the comparative composition C3 (an increase of the termperature range of 55 ^° C, 50 ^° C and 26 ^° C, respectively for E8, E9 and E10).