Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
  • B60C1/0016—Compositions of the tread
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/08—Copolymers of ethene
  • C08L23/0807—Copolymers of ethene with unsaturated hydrocarbons only containing more than three carbon atoms
  • C08L23/0815—Copolymers of ethene with aliphatic 1-olefins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/08—Copolymers of ethene
  • C08L23/0807—Copolymers of ethene with unsaturated hydrocarbons only containing more than three carbon atoms
  • C08L23/0838—Copolymers of ethene with aromatic monomers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2312/00—Crosslinking
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
  • C08L51/06—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond

Definitions

• the present invention relates to a product in subdivided form for preparing crosslinkable elastomeric compositions.
• the present invention relates to a product in subdivided form comprising at least one additive for crosslinkable elastomeric compositions and a thermoplastic binder comprising at least one copolymer of ethylene with at least one ⁇ -olefin.
• additives of the abovementioned type are: vulcanizing agents, crosslinking agents, vulcanization accelerators and retarders, degradation stabilizers, anti-ozone agents, antioxidants, pigments, colorants, crosslinking modifiers, chemical-product stabilizers and heat stabilizers, resins, inhibitors, catalysts capable of extending polymer chains, and the like.
• patent GB 1 389 342 discloses additives in granular form comprising at least one additive for rubbers and at least one substantially saturated elastomeric polymer with thermoplastic properties and, optionally, a dispersant.
• Said elastomeric polymer is preferably readily mixable and compatible with natural and/or synthetic rubbers.
• additives for rubbers which may be used for this purpose include: expanding agents such as sodium bicarbonate; vulcanization accelerators such as hexamethylene tetramine, tetramethyl thiuram disulphide, diethyl thiourea; crosslinking agents such as sulphur; anti- ageing additives such as N-isopropyl-N-phenyl-p- phenylenediamine; activators of various types such as lead oxide, lead dioxide, red lead and zinc oxide.
• elastomeric polymers which may be used for this purpose include: ethylene/vinyl acetate copolymers, ethylene/propylene copolymers, polyisobutylene, and blends thereof.
• dispersants which may be used for this purpose include: esters or fatty alcohols, or zinc oleate.
• the blend of additive, elastomeric polymer and, optionally, dispersant may be prepared in the mixers commonly used in the rubber industry, such as, for example, ram kneaders or mixing rolls.
• the subsequent granulation may be carried out by means of granulators normally used in the rubber industry. In this way, it would be possible to obtain free-flowing, non-tacky granules which may be stored in silos and added automatically during the process for preparing elastomeric compositions.
• Patent US 4 670 181 describes a method for preparing additive granules for rubbers or polymers, which are free-flowing and free of powder, in which a process coadjuvant ("processing aid system") is used comprising, per 100 parts by weight of additive: (1) from 0.2 to about 4 parts by weight of a water-soluble high molecular weight binder chosen from the group consisting of partially or totally hydrolysed polyvinyl alcohol, alkyl or hydroxyalkyl cellulose, polyacrylamides, acrylic acid/acrylamide copolymers, amides, polyacrylic acid polymers, polyethylene oxides; (2) from 0.2 to 1 part by weight of a water-soluble or water-dispersible surfactant; and (3) water.
• a process coadjuvant comprising, per 100 parts by weight of additive: (1) from 0.2 to about 4 parts by weight of a water-soluble high molecular weight binder chosen from the group consisting of partially or totally hydrolysed polyvinyl alcohol, alkyl or hydroxyalkyl
• Said method is particularly useful when the granules are obtained by means of an extrusion process, more particularly when a screw extruder is used.
• additives which may be used include: accelerators, vulcanizing agents, pigments, stabilizers, antioxidants, crosslinking agents, reinforcing fillers, and the like.
• Patent US 4 092 285 describes a composition comprising from about 60% to about 95% by weight of an additive for rubbers or plastics and from about 5% to about 40% by weight of a binder, said binder comprising: at least one compound chosen from (i) liquids that are compatible with said rubbers or plastics and with the other components of the binder, and (ii) waxes with a melting point of between 55°C and 80°C; and a polymer with a high molecular weight (at least about 50,000), said polymer being capable of producing, when combined with the other components of the binder, a non-tacky binder which remains in gel form at temperatures below about 53°C and which is capable of returning to liquid form at temperatures above about 53°C.
• high molecular weight polymers which may be used for this purpose include: ethylene/propylene/diene terpolymers (EPDM) , polyethylene chlorosulphonate (Hypalon®) , natural rubber, neoprene with high hardness and high crystallization speed, and the like.
• additives which may be used for this purpose include: vulcanizing agents, crosslinking agents, vulcanization accelerators and retarders, degradation stabilizers, anti-ozone agents, antioxidants, foaming agents, foaming agent activators, pigments, colorants, crosslinking modifiers, flame retardants, chemical- product stabilizers and heat stabilizers, resins, inhibitors, catalysts capable of extending polymer chains, and the like.
• Said additives are mixed with the abovementioned binder in a mixer at high speed, such as, . for example, a Henschel mixer, thus producing particles of irregular form which may be subsequently transformed into other forms such as, for example, granules, strips, cylinders, pearls, and the like.
• the particles obtained are said to be free-flowing and capable of being accurately added and of dispersing homogeneously and quickly in the elastomeric or plastic compositions into which they are added.
• Patent application DE 196 19 509 describes a binder composition for additives for natural and/or synthetic rubbers, comprising: from 36.25 to 23.75 parts by weight of a trans-polyoctenamer with a Mooney viscosity ML (1+4) at 100°C of between 5 and 10; from 12.50 to 25.00 parts by weight of a polyolefinic elastomer (POE) obtained with etallocene catalysts, having a Mooney viscosity ML (1 + 4) at 100°C of between 5 and 8; from 1 to 3 parts by weight of a paraffin wax with a solidification point of between 40°C and 65°C; from 1 to 3 parts by weight of a fatty acid or a derivative thereof, containing from 13 to 18 carbon atoms and having an iodine number of between 10 and 12; from 5 to 20 parts by weight of a liquid ethylene/propylene elastomer having a Haake viscosity of between 5000 mPa and 15,000
• additives which may be used for this purpose are chosen, for example, from: vulcanization accelerators, anti-ageing agents, vulcanization activators, or mixtures thereof.
• Said composition is used to produce rubber additive granules by means of a continuous process which comprises: weighing out the components of the abovementioned composition, premixing said components in an extruder at a temperature of between 50°C and 80°C, continuing the phase of mixing, homogenizing, granulating and cooling, in a single stage, in a thermostatically regulated compactor, working at a temperature of between 50°C and 80°C.
• the granules obtained have a low melting point.
• Patent application EP 728 797 describes the use of a trans-polyoctenamer combined with silica as a vehicle for fluid additives for elastomeric materials.
• the use of trans-polyoctenamer combined with silica is said to make it possible to obtain a non-tacky masterbatch which may be readily converted into granules.
• the additives for elastomeric compositions in granular form which have been proposed hitherto in the prior art are not capable of ensuring high reliability and consistent results.
• the Applicant believes that a product in subdivided form containing at least one additive for elastomeric compositions needs to have the following characteristics :
• the Applicant has now found that it is possible to obtain a product in subdivided form, in particular for the preparation of crosslinkable elastomeric compositions, having the desired combination of properties as described above, by using a binder with thermoplastic properties comprising at least one copolymer of ethylene with at least one ⁇ -olefin having a molecular weight distribution (MWD) index of less than 5 and a melting enthalpy of at least 30 J/g.
• MWD molecular weight distribution
• the present invention thus relates to a product in subdivided form comprising:
• thermoplastic binder comprising at least (i) one copolymer of ethylene with at least one aliphatic or aromatic ⁇ -olefin, and optionally a polyene, said copolymer being characterized by a molecular weight distribution (MWD) index of less than 5, preferably between 1.5 and 3.5, and a melting enthalpy ( ⁇ H m ) of at least 30 J/g, preferably between 34 J/g and 150 J/g.
• MWD molecular weight distribution
• ⁇ H m melting enthalpy
• Said molecular weight distribution index is defined as the ratio between the weight-average molecular weight (M w ) and the number-average molecular weight (M n ) and may be determined, according to conventional techniques, by gel permeation chromatography (GPC) .
• Said melting enthalpy ( ⁇ H m ) may be determined by means of differential scanning calorimetry and relates to the melting peaks found in the temperature range from 0°C to 200°C.
• the present invention relates to a process for preparing a crosslinkable elastomeric composition, comprising the following stages:
• a base polymer comprising at least one elastomeric polymer with at least one reinforcing filler and at least one plasticizer; adding at least one additive capable of modifying or improving the properties of said elastomeric composition; mixing and dispersing said reinforcing filler, said plasticizer and said additive in said elastomeric polymer;
• said at least one additive is added as a product in subdivided form comprising said at least one additive dispersed in a thermoplastic binder comprising at least (i) one copolymer of ethylene with at least one aliphatic or aromatic ⁇ -olefin, and optionally a polyene, said copolymer being characterized by a molecular weight distribution (MWD) index of less than 5, preferably between 1.5 and 3.5, and a melting enthalpy ( ⁇ H m ) of at least 30 J/g, preferably between 34 J/g and 150 J/g.
• MWD molecular weight distribution
• ⁇ H m melting enthalpy
• the abovementioned process may be carried out in continuous or batchwise mode.
• said copolymer (i) is present in an amount of between 20% and 100% by weight relative to the weight of said thermoplastic binder (b) , preferably between 35% and 100% by weight.
• said additive (a) is present in an amount of between 40% and 95% by weight relative to the total weight of said product in subdivided form, preferably between 50% and 90% by weight, even more preferably between 70% and 80% by weight.
• said thermoplastic binder (b) also comprises from 0% to 80% by weight, relative to the weight of said thermoplastic binder (b) and preferably from 0% to 65% by weight, of at least (ii) one polymer obtained by a metathesis reaction of a cycloalkene.
• said thermoplastic binder (b) also comprises from 0% to 80% by weight, relative to the weight of said thermoplastic binder (b) , preferably from 0% to 65% by weight, of at least (iii) one copolymer of ethylene with at least one ester containing an ethylenic unsaturation.
• said products in subdivided form also comprise from 0% to
• said products in subdivided form also comprise from 0% to
• the expression "product in subdivided form” generally means a product of granular form, with an average diameter generally of between 0.5 mm and about 3 mm, preferably between 1 mm and 2 mm, and a length generally between about 1 mm and 4 mm, preferably between 1.5 mm and 3 mm.
• said products in subdivided form have a Shore A hardness of at least 45 and a Shore D hardness of not more than 65 (measured according to ASTM standard D2240-00) .
• the Shore D hardness is preferably between 20 and 60.
• Additives (a) for crosslinkable elastomeric compositions which may be used in the present invention include, in general, components other than elastomeric polymers, reinforcing fillers and plasticizers, which may be used to modify or improve the properties of elastomeric compositions and which belong to various classes of chemical products.
• said additives (a) belong to the following classes:
• crosslinking agents (al) which may be used in the present invention include:
• TMTD tetramethylthiuram disulphide
• TETD tetraethylthiuram disulphide
• TBTD tetrabutylthiuram disulphide
• MPTD pentamethylenethiuram tetra- or hexasulphide
• accelerators (a2) which may be used in the present invention include: thiazoles such as, for example, 2-mercaptobenzothiazole (MBT) , zinc salt of 2-mercaptobenzothiazole (ZMBT) ,
• 2-mercaptobenzothiazole disulphide MBTS
• 2,4- dinitrophenylmercaptobenzothiazole sulphenamides such as, for example, N-cyclohexyl- 2-benzothiazylsulphenamide (CBS) , N-oxydiethylene- 2-benzothiazylsulphenamide (OBS) , N-t-butyl-2- benzothiazylsulphenamide (TBBS) , N,N-dicyclohexyl- 2-benzothiazylsulphenamide (DCBS) ; guanidines such as, for example, diphenylguanidine (DPG) , di-o-tolylguanidine (DOTG) , o-tolylbiguanide (OTGB) ; thiurams such as : thiuram monosulphides [for example tetramethy1thiuram monosulphide (TMTM) ] ; thiuram
• thermosetting resins (a3) which may be used in the present invention include:
• - hydrocarbon resins such as, for example, ⁇ -methylstyrene-base resins (Kristalex® F-85 from Hercules) ; cumarone-based resins (Cumar® from Neville Chemical) .
• activators (a4) which may be used in the present invention include:
• zinc compounds such as, for example, ZnO, ZnC0 3 , zinc salts of saturated or unsaturated fatty acids containing from 8 to 18 carbon atoms, such as, for example, zinc stearate, preferably formed in situ in the mixture from ZnO and fatty acid, and also BiO, PbO, Pb 3 0 and Pb0 2 ; - l,5-difurfuryl-l,4-pentadiene-3-one, triallyl cyanurate, triallyl isocyanurate, triallyl phosphate, ethylene glycol dimethacrylate (EDMA) , trimethylolpropane trimethacrylate (TPTA) , N,N'-m- phenylenedimaleimide .
• ZnO, ZnC0 3 zinc salts of saturated or unsaturated fatty acids containing from 8 to 18 carbon atoms, such as, for example, zinc stearate, preferably formed in situ in the mixture from ZnO and
• retardants (a5) which may be used in the present invention include:
• carboxylic acids or derivatives thereof such as, for example, benzoic acid, salicylic acid, anhydride of phthalic acid (PTA) ; - phthalimide derivatives such as, for example, N-cyclohexylthiophthalimide; diphenylamine derivatives such as, for example, N-nitrosodiphenylamine (NDPA) .
• PTA phthalic acid
• NDPA N-nitrosodiphenylamine
• adhesion promoting agents (a6) which may be used in the present invention include:
• HMT hexamethylenetetramine
• HMMM hexamethoxymeth lmelamine
• phenol derivatives such as, for example, m-hydroxyphenol (resorcinol) .
• protective agents (a7) which may be used according to the present invention include:
• amine derivatives such as, for example, N-isopropyl-N' -phenyl-p-phenylenediamine (IPPD) , N- (1, 3-dimethylbutyl) -N' -p-phenylenediamine (6PPD), N,N'-bis(l,4-dimethyl ⁇ entyl)-p- phenylenediamine (77PD) , N,N' -bis (l-ethyl-3- methylpentyl) -p-phenyldiamine (DOPD) , N,N'- diphenyl-p-phenylenediamine (DPPD) , N,N' -ditolyl- p-phenylenediamine (DTPD) , N,N' -di- ⁇ -naphthyl-p- phenylenediamine (DNPD) , phenyl- ⁇ -naphthylamine (PAN) and phenyl-
• MMBI 4-methylmercaptobenzimidazole
• phenol derivatives such as, for example, 2,6-di-t- butyl-p-cresol (BHT) , 2, 4-dimethyl-6-t- butylphenol, 2, 4-dimethyl-6- ( ⁇ - ethylcyclohexyl)phenol, 2, 6-di-t-butyl-4- methoxymethylphenol , 2,2' -methylene-bis (4-methyl- 6-t-butylphenol) (BPH) , 2, 2 ' -methylene-bis (4- methyl-6-cyclohexyl) phenol (CPH) , 2,2'- isobutylidene-bis (4, 6-dimethylphenol) (IBPH) , 2,2' -methylene-bis (4-ethyl-6-t-butylphenol) , 4,4'- thio-bis (3-methyl-6-t-butylphenol) , 1,1, 3-tris (2 '
• coupling agents (a8) in particular coupling agents for silica such as hydrolysable silanes containing sulphur, which may be used in the present invention include: 3,3'- bis (trimethoxysilylpropyl) disulphide, 3, 3 ' -bis (tri- ethoxysilylpropyl) tetrasulphide (X50S® from Degussa), 3,3' -bis (triethoxysilylpropyl) octasulphide, 3,3' -bis- (trimethoxysilylpropyl) tetrasulphide, 2,2' -bis (tri- ethoxysilylethyl) tetrasulphide, 3,3' -bis (trimethoxysilylpropyl) trisulphide, 3, 3 '-bis (triethoxysilyl- propyl) trisulphide, 3,3' -bis (tributoxysilylpropyl) -
• the term aliphatic ⁇ -olefin means an olefin of .
• formula CH 2 CH-R, in which R represents a linear or branched alkyl group containing from 1 to 12 carbon atoms.
• the aliphatic ⁇ -olefin is chosen from propylene, 1-butene, isobutylene, 1-pentene, 4-methyl-l-pentene, 1-hexene, 1-octene, 1-dodecene, or mixtures thereof.
• 1-Octene is particularly preferred.
• aromatic ⁇ -olefin means an olefin of formula:
• Ri, R 2 and R 3 which may be identical to or different from each other, represent hydrogen or a linear or branched alkyl group containing from 1 to 8 carbon atoms; or R 3 , different from Ri and R 2 , represents an alkoxy group, a carboxyl group, an acyloxy -group, said acyloxy group optionally being substituted with alkyl groups containing from 1 to 8 carbon atoms or hydroxyl groups or halogen atoms; x is 0 or an integer between 1 and 5 inclusive; y is 0, 1 or 2.
• the aromatic ⁇ -olefin is chosen from styrene, ⁇ -methy1styrene, or mixtures thereof. Styrene is particularly preferred.
• said copolymer (i) is characterized by a high regioregularity in the sequence of monomer units.
• said copolymer contains an amount of -CH 2 - groups in -(CH 2 ) n - sequences, in which n is an even integer, which is generally less than 5 mol% and preferably less than 1 mol% relative to total amount of -CH 2 - groups .
• the amount of -(CH2) n - sequences may be determined according to conventional techiques, by means of 13 C-NMR analysis.
• said copolymer (i) is characterized by a composition distribution index of greater than 45%, said index being defined as the weight percentage of copolymer molecules with an ⁇ -olefin content within 50% of the average total molar content of ⁇ -olefin.
• composition distribution index provides a measure of the distribution of the aliphatic or aromatic ⁇ -olefin among the copolymer molecules, and may be determined by means of Temperature Rising Elution Fractionation techniques as described, for example, in patent US 5 008 204, or in Wild et al . J " . Poly. Sci . Poly, Phys . ed. , Vol. 20, p. 441 (1982).
• polyene means a diene, a triene or a tetraene, which may be conjugated or non-conjugated.
• a diene comonomer When a diene comonomer is present, said comonomer generally contains from 4 to 20 carbon atoms and is preferably chosen from: linear conjugated or non-conjugated diolefins such as, for example, 1, 3-butadiene, 1, 4-hexadiene, 1, 6-octadiene, and the like; monocyclic or polycyclic dienes such as, for example, 1, 4-cyclohexadiene, 5-ethylidene-2- norbornene, 5-methylene-2-norb ⁇ rnene, vinylnorbornene, or mixtures thereof .
• said comonomer When a triene or tetraene comonomer is present, said comonomer generally contains from 9 to 30 carbon atoms and is preferably chosen from trienes and tetraenes containing a vinyl group in the molecule or a 5-norbornen-2-yl group in the molecule.
• triene or tetraene comonomers which may be used in the present invention include: 6,10-dimethyl-l,5,9-undecatriene, 5, 9-dimethyl-l, 4, 8- decatriene, 6, 9-dimethyl-l, 5, 8-decatriene, 6,8,9- trimethyl-1, 6, 8-decatriene, 6, 10, 14-trimethyl-l, 5, 9, 13- pentadecatetraene, or mixtures thereof.
• the polyene is preferably a diene.
• said copolymer (i) consists of copolymers of ethylene and of at least one C 3 -C ⁇ 2 aliphatic ⁇ -olefin, preferably 1- octene, or aromatic ⁇ -olefin, preferably styrene, and optionally a polyene, preferably a diene, characterized by:
• MFI Melt Flow Index
• the copolymer (i) generally has the following composition: 50 mol%-97 mol%, preferably 60 mol%-95 mol%, of ethylene; 3 mol%-50 mol%, preferably 5 mol%-50 mol%, of an aliphatic or aromatic ⁇ -olefin; 0 mol%-5 mol%, preferably 0 mol%-2 mol%, of a polyene.
• the copolymer (i) may be obtained by copolymerization of ethylene with an aliphatic or aromatic ⁇ -olefin, and optionally a polyene, in the presence of a "single- site” catalyst, for example a metallocene catalyst, as described, for example, in patents US 5 246 783 and US 5 272 236.
• a single- site catalyst for example a metallocene catalyst
• the metallocenes used in the polymerization of olefins are coordination complexes between a transition metal, usually from group IV, in particular titanium, zirconium or hafnium, and two cyclopentadienyl ligands, which are optionally substituted, used in combination with a co-catalyst, for example an aluminoxane, preferably a methylaluminoxane, or a boron compound (see, for example, J.M.S. - Rev. Macromol . Chem. Phys., C34(3), 493-514 (1994); J.
• Catalysts that are suitable for obtaining the copolymer (i) according to the present invention also include the "constrained geometry catalysts" described, for example, in patents EP 416 815, EP 418 044 and US 5 703 187.
• copolymers (i) which may be used in the present invention and which are currently commercially available include the products Engage® from DuPont-Dow Elastomer and Exact® from Exxon Chemical .
• the copolymer (i) may optionally contain functional groups chosen from: carboxylic groups, anhydride groups, ester groups, silane groups, epoxide groups.
• the amount of functional groups present in the polymer is generally between 0.05 and 50 parts by weight, preferably between 0.1 and 10 parts by weight, relative to 100 parts by weight of copolymer (i) .
• the functional groups may be introduced during the production of the copolymer (i) , by copolymerization with corresponding functionalized monomers containing at least one ethylenic unsaturation, or by subsequent modification of the copolymer (i) by grafting the abovementioned functionalized monomers in the presence of a free-radical initiator (in particular an organic peroxide) .
• a free-radical initiator in particular an organic peroxide
• the functional groups may be introduced by reacting pre-existing groups on the copolymer (i) with a suitable reagent, for example by means of an epoxidation reaction of a diene polymer containing double bonds along the main chain and/or as side groups with a peracid (for example m-chloroperbenzoic acid or peracetic acid) or with hydrogen peroxide in the presence of a carboxylic acid or a derivative thereof.
• a suitable reagent for example by means of an epoxidation reaction of a diene polymer containing double bonds along the main chain and/or as side groups with a peracid (for example m-chloroperbenzoic acid or peracetic acid) or with hydrogen peroxide in the presence of a carboxylic acid or a derivative thereof.
• Functionalized monomers which may be used, for example, include: silanes containing at least one ethylenic unsaturation; epoxides containing at least one ethylenic unsaturation; monocarboxylic or, preferably, dicarboxylic acids containing at least one ethylenic unsaturation, or derivatives thereof, in particular anhydrides or esters .
• silanes containing at least one ethylenic unsaturation include: ⁇ -methacryloxypropyltrimethoxy- silane, allyltrimethoxysilane, allyltriethoxysilane, allylmethyldimethoxysilane, allylmethyldiethoxysilane, vinyltris (2-methoxyethoxy) silane, vinyltrimethoxy- silane, vinylmethyldimethoxysilane, vinyltriethoxy- silane, and the like, or mixtures thereof.
• epoxides containing at least one ethylenic unsaturation include: glycidyl acrylate, glycidyl methacrylate, itaconic acid monoglycidyl ester, maleic acid glycidyl ester, vinyl glycidyl ether, allyl glycidyl ether, and the like, or mixtures thereof.
• Examples of monocarboxylic or dicarboxylic acids containing at least one ethylenic unsaturation, or derivatives thereof include: maleic acid, maleic anhydride, fumaric acid, citraconic acid, itaconic acid, acrylic acid, ethacrylic acid, and the like, and anhydrides or esters derived therefrom, or mixtures thereof.
• Maleic anhydride is particularly preferred.
• thermoplastic binder (i) may also comprise (ii) a polymer obtained by a metathesis reaction of a cycloalkene.
• the polymer (ii) is a polyoctenamer. Said polymer (ii) preferably has the following characteristics :
• a percentage of double bonds in trans configuration determined by infrared (IR) spectrometry, of at least 60 mol%, preferably between 75 mol% and 95 mol%; - a Mooney viscosity ML (1 + 4) at 125°C, measured according to ASTM standard D1646-00, of between 2 and 20, preferably between 5 and 15; a melting point, measured by DSC (Differential Scanning Calorimetry) of between 25°C and 80°C, preferably between 40°C and 60°C; a glass transition temperature (Tg) , measured according to DIN standard 53445, of between -90°C and -50°C, preferably between -80°C and -60°C.
• IR infrared
• the polymer (ii) may be obtained according to conventional techniques, by a metathesis reaction, in solution, of cycloalkene such as, for example, cyclopentene, cyclooctene, cyclododecene, in the presence of a mixture of catalysts based on metals compounds belonging to subgroups 5-7 and of metals belonging to the main groups 1-4 of the Periodic Table of the Elements (for example the tungsten hexachloride/aluminium ethyl dichloride catalytic system) .
• cycloalkene such as, for example, cyclopentene, cyclooctene, cyclododecene
• a mixture of catalysts based on metals compounds belonging to subgroups 5-7 and of metals belonging to the main groups 1-4 of the Periodic Table of the Elements for example the tungsten hexachloride/aluminium ethyl dichloride catalytic system
• polymers (ii) which may be used in the present invention and which are currently commercially available include the Vestenamer® products from Degussa-Hiils .
• thermoplastic binder (i) may also comprise (iii) a copolymer of ethylene with at least one ester containing an ethylenic unsaturation.
• (iii) is a copolymer of ethylene with at least one ester containing an ethylenic unsaturation, chosen from: alkyl acrylates, alkyl methacrylates and vinyl carboxylates, in which the linear or branched alkyl group may contain from 1 to 8, preferably from 1 to 4 carbon atoms, while the linear or branched carboxylic group may contain from 2 to 8, preferably from 2 to 5 carbon atoms .
• Said ester may be present in the copolymer in an amount of between 5% and 50% by weight, preferably between 15% and 40% by weight.
• acrylates and methacrylates include: ethyl acrylate, methyl acrylate, methyl methacrylate, t-butyl acrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate.
• vinyl carboxylates include: vinyl acetate, vinyl propionate, vinyl butanoate.
• copolymers (iii) which may be used in the present invention include: ethylene/vinyl acetate (EVA) , ethylene/ethyl acrylate (EEA) , ethylene/butyl acrylate (EBA) .
• EVA ethylene/vinyl acetate
• EBA ethylene/butyl acrylate
• the ethylene/vinyl acetate (EVA) copolymer is preferred.
• said products may also comprise an elastomeric polymer (iv) .
• the elastomeric polymer (iv) may be chosen from the diene elastomeric polymers commonly used in sulphur-crosslinkable elastomeric compositions, in particular from elastomeric polymers or copolymers containing an unsaturated chain, with a glass transition temperature generally of less than 20°C, preferably between 0°C and -90°C.
• These polymers or copolymers may be of natural origin or may be obtained by solution polymerization or emulsion polymerization of one or more conjugated diolefins, optionally mixed with one or more monovinylarenes in amounts generally not greater than 50% by weight.
• the conjugated diolefins generally contain from 4 to 12, preferably from 4 to 8 carbon atoms, and may be chosen from the group comprising: 1, 3-butadiene, isoprene, 2, 3-dimethyl-l, 3-butadiene, 1, 3-pentadiene, 1, 3-hexadiene, 3-butyl-l, 3-octadiene, 2-phenyl-l, 3- butadiene, or mixtures thereof. 1, 3-Butadiene and isoprene are particularly preferred.
• Monovinylarenes which may optionally be used as comonomers generally contain from 8 to 20, preferably from 8 to 12 carbon atoms, and may be chosen, for example, from: styrene; 1-vinylnaphthalene;
• 2-vinylnaphthalene various alkyl , cycloalkyl, aryl , alkylaryl or arylalkyl derivatives of styrene, such as , for example : ⁇ -me thy 1 styrene, 3 -methyl styrene, 4-propylstyrene, 4 -cyclohexyl styrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4-p-tolylstyrene , 4- (4- phenylbutyl) styrene, or mixtures thereof .
• Styrene is particularly preferred.
• the elastomeric polymer (iv) which may be used according to the present invention may be chosen from: cis-1 , 4-polyisoprene (natural or synthetic, preferably natural rubber) , 3 , 4-polyisoprene, polychloroprene, optionally halogenated isoprene/ isobutene copolymers , 1 , 3- butadiene/acrylonitrile copolymers, styrene/1 , 3- butadiene copolymers , styrene/isoprene copolymers , styrene/ isoprene/ 1 , 3-butadiene copolymers ; or mixtures thereof .
• the elastomeric polymer (iv) may be chosen from elastomeric polymers of one or more monoolefins with an olefinic comonomer or derivatives thereof, said elastomeric polymer (iv) being characterized by a melting enthalpy ( ⁇ H m ) of less than 15 J/g.
• the monoolefins may be chosen from: ethylene and ⁇ -olefins generally containing from 3 to 12 carbon atoms, such as, for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, or mixtures thereof.
• copolymers of ethylene and of an ⁇ -olefin, and optionally of a diene are preferred: copolymers of ethylene and of an ⁇ -olefin, and optionally of a diene; isobutene homopolymers or copolymers thereof with smaller amounts of a diene, which are optionally at least partially halogenated.
• the diene which may be present generally contains from 4 to 20 carbon atoms and is preferably chosen from: 1, 3-butadiene, isoprene, 1, 4-hexadiene, 1,4- cyclohexadiene, 5-ethylidene-2-norbornene, 5-methylene- 2-norbornene, vinylnorbornene, or mixtures thereof.
• the dienes that are particularly preferred include: ethylene/propylene copolymers (EPR) or 5 ethylene/propylene/diene copolymers (EPDM) ; polyisobutene; butyl rubbers; halobutyl rubbers, in particular chlorobutyl or bromobutyl rubbers; or mixtures thereof .
• said products may also comprise a reinforcing filler (v) .
• the reinforcing filler (v) is chosen from carbon black or from the so-called white fillers such as, for example, silica, alumina, aluminosilicates, calcium carbonate, kaolin, titanium dioxide, or mixtures thereof.
• the products in subdivided form of the present invention may also comprise plasticizer (vi) .
• the plasticizer (vi) is, in some cases, already present in the additive (a) such as, for example, in the case of the sulphur which is commonly commercialized as a dispersion in an oil 30 (referred to as sulphur oleate) since, in the absence of oil, sulphur presents either handling and processability problems due to its tendency to form large aggregates, or hazard problems due to its flammability.
• the plasticizer (vi) is chosen from mineral oils such as, for example, paraffinic oils, naphthenic oils, aromatic oils; vegetable oils; or mixtures thereof. Paraffinic oils are particularly preferred.
• said products may also comprise at least one pigment chosen from the organic and inorganic pigments usually used in elastomeric compositions.
• the amount of pigment used is such that it gives the product in subdivided form a sufficient coloration.
• the products in subdivided form according to the present invention may be obtained by mixing the various components, followed by granulation by means of various processes. Said mixing may be carried out, for example, using an open mill or an internal mixer of the type with tangential rotors (Banbury) or with interlocking rotors (Intermix) , or in continuous mixers such as a Ko-Kneader mixer (Buss) , or by extrusion using co- rotating or counter-rotating twin-screw extruders or using single-screw extruders.
• an open mill or an internal mixer of the type with tangential rotors (Banbury) or with interlocking rotors (Intermix) or in continuous mixers such as a Ko-Kneader mixer (Buss) , or by extrusion using co- rotating or counter-rotating twin-screw extruders or using single-screw extruders.
• the subsequent granulation may be carried out, for example, by grinding the mixture obtained or, in the case of extrusion, by means of a uniform chopping of the extruded material in the form of "spaghetti" (for example using a chopper) .
• the process for preparing a crosslinkable elastomeric composition according to the present invention may be carried out in continuous or batchwise mode.
• the mixing of the polymer base with the other components and with the product in subdivided form is carried out, for example, in continuous mixers such as a Ko-Kneader mixer (Buss) or in co-rotating or counter- rotating twin-screw extruders or in single-screw extruders.
• continuous mixers such as a Ko-Kneader mixer (Buss) or in co-rotating or counter- rotating twin-screw extruders or in single-screw extruders.
• the mixing of the polymer base with the other components and with the products in subdivided form is carried out, for example, using an open internal mixer such as an open mill, or an internal mixer of the type with tangential rotors (Banbury) or with interlocking rotors (Intermix) .
• the temperature is kept below a predetermined value so as to avoid premature crosslinking of the composition.
• the temperature is generally kept below 170°C, preferably below 150°C, even more preferably below 120°C.
• the mixing time this may vary within a wide range, depending mainly on the specific composition of the mixture, on the presence of reinforcing fillers and on the type of mixer used. In general, a mixing time of more than 90 seconds, preferably between 3 minutes and 35 minutes is sufficient to obtain a homogeneous composition.
• Said reinforcing filler is generally chosen from carbon black or from the so-called white fillers such as, for example, silica, alumina, aluminosilicates, calcium carbonate, kaolin, titanium dioxide, or mixtures thereof .
• the melting enthalpy ( ⁇ H m ) of the ethylene/1-octene copolymer mentioned above was measured by differential scanning calorimetry using a Mettler machine, working under the following conditions.
• a sample (about 10 mg) of the ethylene copolymer to be analysed was cooled to -25°C and then heated to 200°C at a scanning speed equal to 20°C/min.
• the sample was held at 200°C for 5 minutes and then cooled to 0°C at a scanning speed equal to 20°C/min. After 5 minutes at 0°C, the sample was again heated to 200°C at a scanning speed equal to 10°C/min.
• melting enthalpy ( ⁇ H m ) and melting temperature (T m ) values reported refer to this second heating phase (second melting values) and correspond, respectively, to the area subtended by the melting peaks between 0°C and 200°C and to the temperature value corresponding to the maximum of these peaks.
• ethylene/1-octene copolymer 0.75 kg/h
• polyoctenamer 0.75 kg/h
• zinc oxide powder 8.5 kg/h.
• the abovementioned mixture was extruded through a die 3.5 mm in diameter, at a screw spin speed of 195 rpm and a constant temperature profile of 205°C.
• the extruded material in the form of "spaghetti" was cooled in a water bath, dried in a stream of air and chopped using a chopper, to give granules having the following dimensions: diameter 2 mm, length 3 mm. Granules thus obtained were free of powder.
• paraffin wax paraffin wax
• carbon black N660
• the melting enthalpy ( ⁇ H m ) of the ethylene/1-octene copolymer given above was measured as , described in Example 1.
• paraffin wax 4.66 kg/h
• carbon black 2.34 kg/h
• ethylene/1-octene copolymer 3 kg/h.
• the abovementioned mixture was extruded through a die 3.5 mm in diameter, with a screw spin speed of 250 rpm and a constant temperature profile of 60°C.
• the extruded material in the form of "spaghetti" was cooled in a water bath, dried in a stream of air and chopped using a chopper, to give granules having the following dimensions: diameter 2 mm, length 3 mm.
• the granules thus obtained were free of dusts .
• the abovementioned mixture was extruded through a die 3.5 mm in diameter, at a screw spin speed of 200 rpm and at a constant temperature profile of 68°C.
• the extruded material in the form of "spaghetti" was cooled in a water bath, dried in a stream of air and chopped using a chopper, to give granules having the following dimensions: diameter 2 mm, length 3 mm.
• the granules thus obtained were free of dusts .
• N-cyclohexyl-2-benzothiazyl sulphenamide (CBS Santocure® from Monsanto) .
• N-cyclohexyl-2-benzothiazyl sulphenamide 5.6 kg/h.
• ethylene/1-octene copolymer 1.5 kg/h
• polyoctenamer 1.5 kg/h
• - poly- ⁇ -methylstyrene resin 7 kg/h
• paraffin wax 7 kg/h.
• the abovementioned mixture was extruded through a die 3.5 mm in diameter, at a screw spin speed of 320 rpm and at a constant temperature profile of 70°C.
• the extruded material in the form of "spaghetti" was cooled in a water bath, dried in a stream of air and chopped using a chopper, to give granules having the following dimensions: diameter 2 mm, length 3 mm. The granules thus obtained were free of dusts .
• ethylene/1-octene copolymer 0.5 kg/h; zinc stearate: 9 kg/h; stearic acid: 9 kg/h; - carbon black: 9 kg/h.
• the abovementioned mixture was extruded through a die 3.5 mm in diameter, at a screw spin speed of 250 rpm and at a constant temperature profile of 85°C.
• the extruded material in the form of "spaghetti" was cooled in a water bath, dried in a stream of air and chopped using a chopper, to give granules having the following dimensions: diameter 2 mm, length 3 mm. The granules thus obtained were free of dusts .
• Example 1-6 The granules of Examples 1-6 were subjected to flowability tests.
• a funnel consisting of a first portion of frustoconical shape (hopper) followed by a second portion defining an outlet channel from said first portion, was used.
• Said funnel had the following characteristics:
• hopper angle 60°; length of the outlet channel: 10 cm; initial diameter of the outlet channel: 2.8 cm; final diameter of the outlet channel: 1.8 cm.
• hopper angle means the angle between a directrix of the frustoconical surface of said hopper and the longitudinal axis of said outlet channel.
• volume of the cylindrical chamber 250 ml; diameter of the cylindrical chamber: 7.5 cm; amount of granules: 50 ml; spin speed: 500 rpm; grinding time: 3 min.

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