JP2008231432A - Tire containing ethylene copolymer, tread band, and elastomer composition used for them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire for a wheel, a tread band, and a crosslinking elastomer composition. <P>SOLUTION: This tire is the tire for the wheel equipped with at least a component part manufactured from a crosslinking elastomer, and the component part comprises an elastomer composition comprising (a) at least a kind of diene elastomer polymer, and (b) an elastomer composition containing ethylene, at least a kind of aliphatic α-olefin, and arbitrarily at least a kind of copolymer with a polyene, and the copolymer has a molecular weight distribution (MWD) index of less than 5, preferably 1.5-3.5, melt enthalpy (ΔaH<SB>m</SB>) of not smaller than 30 J/g, preferably 34 J/g-130 J/g. The component part containing the composition is preferably a tire tread band. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a tire for a wheel, a tread band, and a crosslinkable elastomer composition.

  More particularly, the invention relates to a wheel tire comprising at least one component made from a crosslinked elastomeric material comprising at least one copolymer of ethylene and at least one aliphatic α-olefin.

  The present invention further includes a tread band comprising a crosslinkable elastomer composition comprising at least one copolymer of ethylene and at least one aliphatic α-olefin, and at least of ethylene and at least one aliphatic α-olefin. It relates to an elastomeric composition comprising one type of copolymer.

  In the rubber industry, especially the wheel tire industry, it is a well known practice to use elastomeric compositions that have good tear and resistance as well as good static and dynamic mechanical properties. In particular, tear resistance is the most important characteristic in the case of a tire tread band.

  Improved tear resistance can be obtained, for example, by increasing the hardness of the elastomeric composition.

  The hardness of the elastomeric composition may be, for example, using a higher amount of sulfur to increase the crosslink density of these compositions, or a higher amount of carbon black, or a finer, more structured carbon black. Can be increased.

  However, excessive hardness, for example, causes a number of drawbacks, such as a decrease in elongation at break, and in particular the phenomenon known as “chipping” (rubber pieces separate from the tire). There is a case.

  Carbon black is well-known to give significant hysteresis properties to cross-linked products, i.e., increased heat dissipation under dynamic conditions, which has been found to increase tire rolling resistance in the case of tires. Yes. Furthermore, carbon black increases the viscosity of the elastomeric composition, and as a result has a negative impact on the processability and extrudability of the composition.

  In order to overcome the above drawbacks, so-called “white” reinforcing fillers, in particular silica, are generally used in whole or in part with carbon black. However, the use of said reinforcing fillers provides good tear resistance, but with a series of drawbacks associated with the poor affinity of these fillers with elastomers commonly used in tire manufacture. . In particular, in order to disperse the silica to a good extent in the polymer matrix, it is necessary to subject the elastomer blend to a thermomechanical blending action for a long time. To increase the affinity between the silica and the elastomeric matrix, it is necessary to use a suitable coupling agent, such as, for example, a sulfur-containing organosilane product. However, the need to use such coupling agents constrains the maximum temperature that can be reached during blending and thermomachining of the composition to prevent the irreversible thermal degradation of the coupling agent.

  In the prior art, for example, it has been proposed to introduce a thermoplastic polymer into an elastomeric composition, in particular an elastomeric composition used to produce a tread band of a tire.

U.S. Patent No. 4 675 349, an average molecular weight of about 1,000,000 to 6,000,000, preferably 1,500,000, density of small amounts of 0.93g ^/ cm ³ ~0.95g ^/ cm 3 density crystalline linear A crosslinkable elastomeric composition comprising polyethylene is described. The composition is used to produce a tread band for a tire and is said to give the tire both low hysteresis and good road surface retention while not changing the hardness, wear and tear resistance characteristics.

In US Pat. No. 5,341,863, the tread band comprises (A) 100 parts by weight of at least one sulfur sulfide diene elastomer polymer, and (B) a density of about 0.91 g / cm ^{3 to} 0.918 g / A tire is described comprising a sulfur crosslinkable elastomeric composition comprising from about 5 to about 15 parts by weight of cm ³ of low density polyethylene (LDPE). The addition of the polyethylene is said to provide improved extrudability and tear resistance to the elastomeric composition.

  In US Pat. No. 6,028,143, 100 parts by weight of an elastomeric matrix, 0% to 80% polyethylene, and at least 20% composite material comprising polyethylene, and pre-bonded to the polyethylene by a coupling agent, An elastomer composition is described comprising an elastomer matrix and 2 to 75 parts by weight of a composition comprising an elastomeric polymer to be crosslinked. By using the composite material, the dispersion of polyethylene in the elastomer matrix is improved and the interaction between polyethylene and the elastomer matrix is enhanced, resulting in low hysteresis, good thermal resistance, and high level of hardness. It is said that an elastomer composition having the above can be obtained, and that the tear resistance property is not negatively affected. The above elastomer composition can be used for production of a tread band.

  US Pat. No. 6,037,418 includes an elastomeric polymer and a polyolefin, wherein (1) the polyolefin is in the form of particles dispersed in the elastomeric polymer, the average particle size is less than 1 μm, (2) the elastomeric polymer and A reinforced elastomeric resin is described in which the polyolefins are bonded together by a silane coupling agent. Useful polyolefins for this purpose include polyethylene, polypropylene, high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and the like. The above reinforced elastomeric resin is said to have uniform modulus, low density and excellent tensile strength, fatigue strength and wear resistance. The elastomer composition can be used for producing a tread band.

  In the applicant's opinion, elastomeric compositions comprising thermoplastic polymers need to meet various requirements in order to be able to be used efficiently and advantageously in the manufacture of crosslinked products, in particular tires. .

In particular, applicants of the present application need to meet the following requirements when a thermoplastic polymer is present in the elastomeric composition:
Increase the tear resistance, so that it does not impair the breaking properties of the composition (stress at break and elongation at break) and improves if possible;
Reducing the viscosity, so that it is possible to obtain an elastomer composition having good processability and good extrudability;
Reducing the density, so that it is possible to obtain a crosslinked product which is relatively light and has a relatively low rolling resistance in the case of wheel tires;
-Does not increase hardness;
-Does not negatively affect other mechanical properties, both static properties (especially elastic modulus) and dynamic properties (especially dynamic elastic modulus and tan delta).

  The applicant of the present application is a copolymer of ethylene and at least one aliphatic α-olefin having a molecular weight distribution (MWD) index of less than 5 and a melting enthalpy of 30 J / g. It has been discovered that the above copolymer can be used to obtain a crosslinkable elastomeric composition that can be advantageously used in the manufacture of crosslinked products, particularly tires. The ethylene copolymer can meet the above requirements.

In a first aspect, the present invention is a wheel tire including at least one component manufactured from a crosslinked elastomeric material, wherein the component includes:
(A) at least one diene elastomer polymer;
(B) at least one copolymer of ethylene, at least one aliphatic α-olefin, and optionally polyene, having a molecular weight distribution (MWD) index of less than 5, preferably 1.5 to 3.5. A copolymer having a melting enthalpy (ΔH _m ) of 30 J / g or more, preferably 34 J / g to 130 J / g,
The present invention relates to a tire including an elastomer composition including

The molecular weight distribution index is defined as a ratio between the weight average molecular weight (M _w ) and the number average molecular weight (M _n ), and can be determined by gel permeation chromatography (GPC) according to conventional techniques.

The melting enthalpy (ΔH _m ) can be determined by differential scanning calorimetry and is related to a melting peak detected in the temperature range of 0 ° C. to 200 ° C.

According to a preferred embodiment, the present invention is a wheel tire,
A carcass structure with at least one carcass ply shaped substantially in a toroidal configuration, the opposing side edges respectively corresponding to the right and left bead wires, each bead wire being in its own bead Surrounded by carcass structure,
A belt structure comprising at least one belt strip applied at a circumferentially outer position relative to the carcass structure;
-A tread band superimposed on the belt structure in the circumferential direction;
A pair of side walls provided on both sides of the carcass structure;
(A) at least one diene elastomer polymer;
(B) at least one copolymer of ethylene, at least one aliphatic α-olefin and optionally a polyene, said copolymer having a molecular weight distribution (MWD) index of less than 5, preferably 1.5 -3.5, a copolymer characterized by a melting enthalpy (ΔH _m ) of 30 J / g or more, preferably 34 J / g to 130 J / g,
The tire component is a tread band.

According to another aspect, the present invention is a tire tread band for wheels,
(A) at least one diene elastomer polymer;
(B) at least one copolymer of ethylene, at least one aliphatic α-olefin, and optionally polyene, having a molecular weight distribution (MWD) index of less than 5, preferably 1.5 to 3.5. A copolymer having a melting enthalpy (ΔH _m ) of 30 J / g or more, preferably 34 J / g to 130 J / g,
The present invention relates to a tread band containing a crosslinkable elastomer composition containing

According to yet another aspect, the present invention is an elastomer composition comprising:
(A) at least one diene elastomer polymer;
(B) at least one copolymer of ethylene, at least one aliphatic α-olefin, and optionally polyene, having a molecular weight distribution (MWD) index of less than 5, preferably 1.5 to 3.5. A copolymer having a melting enthalpy (ΔH _m ) of 30 J / g or more, preferably 34 J / g to 130 J / g,
It relates to the elastomer composition containing this.

According to yet another aspect, the present invention is a crosslinked elastomer product comprising:
(A) at least one diene elastomer polymer;
(B) at least one copolymer of ethylene, at least one aliphatic α-olefin, and optionally polyene, having a molecular weight distribution (MWD) index of less than 5, preferably 1.5 to 3.5. A copolymer having a melting enthalpy (ΔH _m ) of 30 J / g or more, preferably 34 J / g to 130 J / g,
It is related with the crosslinked elastomer product obtained by bridge | crosslinking the elastomer composition containing this.

  According to one preferred embodiment, said copolymer (b) of ethylene and at least one aliphatic α-olefin is an elastomeric composition in an amount of 0.1 phr to 100 phr, preferably 3 phr to 50 phr, more preferably 5 phr to 20 prh. It exists in things.

  For purposes of this specification and claims, the phrase “phr” refers to 100 parts by weight of the elastomer base and parts by weight of a particular component of the elastomer composition.

According to one preferred embodiment, the diene elastomeric polymer (a) used in the present invention is derived from polymers commonly used in sulfur-crosslinkable elastomeric compositions particularly suitable for the manufacture of tires, ie elastomeric polymers, or generally below 20 ° C. , Preferably selected from copolymers with unsaturated chains having a glass transition temperature (T _g ) of 0 ° C. to −90 ° C. These polymers or copolymers are naturally derived or obtained by solution polymerization, emulsion polymerization or gas phase polymerization of one or more co-beneficial diolefins, optionally monovinylarene and / or polar in an amount of up to 60% by weight Optionally blended with at least one comonomer selected from comonomers.

  Conjugated diolefins generally contain 4 to 12, preferably 4 to 8, carbon atoms such as 1,3-butadiene; isoprene; 2,3-dimethyl-1,3-butadiene; 1,3-pentadiene; Selected from the group comprising 1,3-hexadiene; 3-butyl-1,3-octadiene; 2-phenyl-1,3-butadiene or mixtures thereof. 1,3-butadiene and isoprene are particularly preferred.

  Monovinylarene optionally used as a comonomer generally contains 8 to 20, preferably 8 to 12, carbon atoms, such as styrene; 1-vinylnaphthalene; 2-vinylnaphthalene; various alkyls; cycloalkyl; aryl Alkylaryl or arylalkyl derivatives of styrene such as α-methylstyrene; 3-methylstyrene; 4-propylstyrene; 4-cyclohexylstyrene; 4-dodecylstyrene; 2-ethyl-4-benzylstyrene; 4-p-tolyl Styrene; selected from 4- (4-phenylbutyl) styrene or mixtures thereof. Styrene is particularly preferred.

  Polar comonomers that can optionally be used are, for example, vinyl pyridine; vinyl quinoline; acrylic acid and alkyl acrylates; nitriles; or mixtures thereof such as methyl acrylate; ethyl acrylate; methyl methacrylate; ethyl methacrylate; acrylonitrile or these A mixture can be selected.

  Preferably, the diene elastomeric polymer (a) used in the present invention is, for example, cis-1,4-polyisoprene (natural or synthetic, preferably natural rubber); 3,4-polyisoprene; polybutadiene (especially high 1 , 4-cis component polybutadiene); optionally halogenated isoprene / isobutene copolymer, 1,3-butadiene / acrylonitrile copolymer; styrene / 1,3-butadiene copolymer; styrene / isoprene / 1,3-butadylene copolymer; It can be selected from styrene / 1,3-butadiene / acrylonitrile copolymers or mixtures thereof.

The elastomer composition according to the present invention is at least one elastomer polymer (c) of at least one monoolefin and an olefin comonomer or derivative thereof, and has a melting enthalpy (ΔH _m ) of less than 15 J / g. Optionally containing an elastomeric polymer. The monoolefin can be selected from ethylene and α-olefins generally containing from 3 to 12 carbon atoms such as propylene; 1-butene; 1-pentene; 1-hexene; 1-octene or mixtures thereof. The following are preferred: copolymers of ethylene and alpha-olefins, optionally dienes; isobutene homopolymers, or copolymers with small amounts of dienes, optionally at least partially halogenated copolymers. The diene optionally present generally contains 4 to 20 carbon atoms, preferably 1,3-butadiene, isoprene, 1,4-hexadiene, 1,4-cyclohexadiene, 5-ethylidene-2-norbornene, 5 -Methylene-2-norbornene, vinyl norbornene or a mixture thereof is preferably selected. Among these, the following are particularly preferred: ethylene / propylene copolymer (EPR) or ethylene / propylene / diene copolymer (EPDM), polyisobutene, butyl rubber, halobutyl rubber, in particular chlorobutyl or bromobutyl rubber, or mixtures thereof.

  Diene elastomeric polymer (a) or elastomeric polymer (c) functionalized by reaction with a suitable end agent or coupling agent may be used. In particular, the diene elastomeric polymer obtained by anionic polymerization in the presence of an organometallic initiator (especially an organolithium initiator) has a residual organometallic group derived from the initiator as a suitable end agent or coupling agent, for example Imine; carbodiimide; halogenated alkyltin; substituted benzophenone; can be functionalized by reaction with alkoxylane or aryloxirane (see, eg, EP 451604, or US Pat. No. 4,742,124 and US Pat. No. 4,550,142). ).

With respect to copolymer (b) of ethylene and at least one aliphatic α-olefin, the term “aliphatic α-olefin” has the formula CH ₂ ═CH—R, where R is 1 to 12 carbons. It generally means an olefin in the form of a linear or branched alkyl group containing an atom. Preferably, the aliphatic α-olefin is selected from propylene; 1-butene; isobutylene; 1-pentene; 4-methyl 1-pentene; 1-hexene; 1-octene; 1-dodecene or mixtures thereof. 1-octene is particularly preferred.

  With respect to copolymer (b) of ethylene and at least one aliphatic α-olefin, the term “polyene” generally means conjugated or non-conjugated dienes, trienes or tetraenes. When a diene comonomer is present, this comonomer generally contains 4 to 20 carbon atoms and is a linear or non-common olefin, such as 1,3-butadiene; 1,4-hexadiene; 1,6-octadiene. It is preferred to select from monocyclic or polycyclic dienes such as 1,4-cyclohexadiene; 5-ethylidene-2-norbornene; 5-methylene-2-norbornene; vinyl norbornene or mixtures thereof. When a triene or tetraene comonomer is present, this comonomer is generally selected from trienes or tetraenes containing from 9 to 30 carbon atoms and containing vinyl groups in the molecule or 5-norbornen-2-yl groups in the molecule. It is preferable. In the present invention, specific examples of diene or tetraene comonomer are used: 6,10-dimethyl-1,5,9-undecatriene; 5,9-dimethyl-1,4,8-decatriene; -Dimethyl-1,5,8-decatriene; 6,8,9-trimethyl-1,6,8-decatriene; 6,10,14-trimethyl-1,5,9,13-pentadecatetraene or these It is preferred to select from a mixture. Preferably the polyene is a diene.

According to another preferred embodiment, said copolymer (b) of ethylene and at least one aliphatic α-olefin is
- density of ^{0.86g / cm 3 ~0.93g / cm 3} , preferably ^{0.86g / cm 3 ~0.89g / cm 3} ,
The melt flow index (MFI) is 0.1 g / 10 min to 35 g / 10 min, preferably 0.5 g / 10 min to 20 g / 10 min, as measured according to ASTM standard D1238-00;
-Melting | fusing point ( _Tm ) is 30 degreeC or more, Preferably it is 50 to 120 degreeC, More preferably, it is 55 to 110 degreeC.

  The copolymer of ethylene and at least one aliphatic α-olefin (b) has the following composition: 50 mol% to 98 mol%, preferably 60 mol% to 93 mol% ethylene; 2 mol% to 50 mol%, preferably 7 mol% to 40 mol% aliphatic α-olefin; 0 mol% to 5 mol%, preferably 0 mol% to 2 mol% polymer.

According to yet another preferred embodiment, said copolymer (b) of ethylene and at least one aliphatic α-olefin is characterized by a high degree of regioregularity in the arrangement of molecular units. In particular, the copolymer has an amount of —CH ₂ — in the — (CH ₂ ) _n — sequence, where n is less than 5 mol% relative to the total amount of —CH ₂ — groups, preferably 3 It is an even integer of less than mol%, more preferably less than 1 mol%. - _{(CH 2) n} - amount of sequence is determined by the ¹³ C-NMR analysis in accordance with conventional techniques.

  According to yet another preferred embodiment, said copolymer (b) of ethylene and at least one aliphatic α-olefin is characterized by a composition distribution index greater than 45%, said index being α -Defined as the weight percent of copolymer molecules having an alpha olefin mole content in the range of 50% of the average total mole fraction of olefins.

  The composition distribution index is a unit of measurement of the distribution of aliphatic α-olefins in the copolymer molecule, such as those described in US Pat. No. 5,008,204 or J. Pat. Poly. Sci. Poly, Phys. Ed. 20, page 441 (1982), and can be determined by the temperature rising elution fractionation method.

  The copolymer of ethylene and at least one aliphatic α-olefin (b) is prepared in the presence of a single site catalyst, such as a metallocene catalyst, or a so-called “Constrained Geometry Catalyst”. -Obtained by copolymerization with olefins.

  The metallocene catalyst used for the polymerization of olefins is, for example, generally a transition metal of type IV, in particular titanium, zirconium or hafnium, and two optionally substituted cyclopentadienyl ligands, comprising a promoter, For example, a coordination complex between an aluminoxane, preferably methylaluminoxane, or a ligand used in combination with a boron compound. (For example, Adv.Organome.Chem. (Organic Metal Chemistry) Vol. 18, 99 (1980); Adv.Organome. Chem. (Organic Metal Chemistry), 32, 325 (1991) ); JMS-Rev. Macromol. Chem. Phys. (Polymer Chemistry Physics), C34 (3), 439-514 (1994); J. Organometallic Chemistry (organometallic chemistry) 479, pp. 1-29 (1994); Angew.Chem.int.Ed.Engl.34, 1143 (1995); Prog.Polym.Sci., 20,459 (1995). Adv.Polym.Sci. (Polymer Chemistry), Vol.127 144 (1997), U.S. Pat. No. 5,229,478 or patent applications WO 93/19107, EP 35 342, EP 129 368, EP 277 003, EP 277 004, EP 632 065. )

  So-called “geometrically constrained catalysts” used in the polymerization of olefins are, for example, generally 3-10 or lanthanide-based metals and one optionally substituted cyclopentadienyl ligand, Coordination complexes with ligands used in combination with catalysts such as aluminoxanes, preferably methylaluminoxane or boron compounds. (For example, Organometallics, Vol. 16, page 3649 (1997); J. Am. Chem. Soc., 118, 13021 (1996); J. Am. Chem. Soc., Vol. 118, 12451 (1996); J. Organometallic Chemistry, 482, 169 (1994); J. Am. Chem. Soc., 116, 4623 (1994). Organometallics, Vol. 9, page 867 (1990); U.S. Pat. No. 5,096 867, U.S. Pat. No. 5,414,040, or patent applications WO 92/00333, WO 97/15583, WO 01/12708. No., EP416 8 No. 5, EP418 044 No., EP420 436 No., see No. EP514 828.)

  The synthesis of copolymer (b) of ethylene and at least one aliphatic α-olefin in the presence of a metallocene catalyst is described, for example, in patent application EP206 794, or Metallocene-based Polyolefins (metallocene-based polyolefins), Volume 1, Wiley series in Polymer Science (Polymer Science Willy Series, page 309 (1999)).

  Synthesis of copolymer (b) in the presence of a so-called “geometrically constrained catalyst” of ethylene and at least one aliphatic α-olefin is described, for example, in Macromol. Chem. Rapid. Commun. 20: 214-218 (1999); Macromolecules, 31: 4724 (1998); Macromolecules Chem. Phys. 197, 4237 (1996); or patent application WO 00/26268 or US Pat. No. 5,414,040.

  The copolymer of ethylene and at least one aliphatic α-olefin (b) can optionally contain functional groups selected from: carboxyl groups, anhydride groups, ester groups, silane groups, epoxide groups. The amount of functional groups present in the copolymer is generally 0.05 to 50 parts by weight, preferably 0.1 to 100 parts by weight with respect to 100 parts by weight of the copolymer of ethylene and at least one aliphatic α-olefin (b). 10 parts by weight.

  The functional group is introduced during the formation of the copolymer of low ethylene and at least one aliphatic α-olefin (b) and is thus copolymerized with the corresponding functionalized monomer containing at least one ethylenic unsaturation, or The functionalized monomer is graft polymerized in the presence of a free radical initiator (especially an organic peroxide) to subsequently modify the copolymer of ethylene and at least one aliphatic α-olefin (b).

  Alternatively, the introduction of the functional group may be carried out by reacting an existing group with an appropriate reactant on the copolymer of ethylene and at least one aliphatic α-olefin (b), for example along the main chain, And / or by epoxidizing a diene polymer containing a double bond as a side group with a peracid (eg m-chloroperbenzoic acid or peracetic acid) or hydrogen peroxide in the presence of a carboxylic acid or derivative thereof. It can be carried out.

  Functionalized monomers that can be used include silanes containing at least one ethylenic unsaturation; epoxides containing at least one ethylenic unsaturation; monocarboxylic acids containing at least one ethylenic unsaturation, preferably dicarboxylic acids, or Derivatives, especially anhydrides or esters.

  Examples of silanes containing at least one ethylenic unsaturation include γ-methacryloxypropyltrimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, allylmethyldimethoxysilane, allylmethyldiethoxysilane, vinyltris (2-methoxy Ethoxy) silane, vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyltriethoxysilane, or mixtures thereof.

  Examples of epoxides containing at least one ethylenic unsaturation include glycidyl acrylate, glycidyl methacrylate, monoglycidyl ester of itaconic acid, glycidyl ester of maleic acid, vinyl glycidyl ether, allyl glycidyl ether, or mixtures thereof.

  Examples of monocarboxylic or dicarboxylic acids containing at least one ethylenic unsaturation or derivative thereof include maleic acid, maleic anhydride, fumaric acid, citraconic acid, itaconic acid, acrylic acid, methacrylic acid or mixtures thereof, and Anhydrides or esters derived therefrom, or mixtures thereof. Maleic anhydride is particularly preferred.

  Examples of copolymers (b) of ethylene and at least one aliphatic α-olefin used in the present invention and commercially available include DuPont-Dow Elastomers Engage® ( Engage) and Exxon Chemical's Exact® product.

  At least one reinforcing filler can be advantageously added to the elastomeric composition in accordance with the present invention, generally in an amount of at least 0.1 phr to 120 phr, preferably 20 phr to 90 phr. The reinforcing filler can be selected from those commonly used in crosslinked products, particularly for tires, such as carbon black, silica, alumina, aluminosilicate, calcium carbonate, kaolin, or mixtures thereof.

The type of carbon black used in accordance with the present invention is conventionally used in the manufacture of tires and can generally be selected from those having a surface area of 20 m ² / g (determined by CTAB absorption as described in ISO standard 6810). ).

Silica used according to the invention, generally, (measured by ISO Standard 5794/1) BET surface area of ^{50m 2} / ^g~500m 2 / g, pyrogenic silica is preferably ^{70m 2} / ^g~200m 2 / g, Precipitated silica is preferred.

  When a reinforcing filler comprising silica is present, the elastomeric composition can advantageously include a coupling agent that can interact with the silica during the vulcanization process to bind the silica to the elastomer base.

Coupling agents that are preferably used are, for example, silane-based coupling agents specified by the following structural formula (II):
(R) ₃ Si—C _n H _2n —X (II)
In which the R groups may be the same or different and are selected from alkyl, alkoxy or aryloxy groups or halogen atoms, provided that at least one of the R groups is an alkoxy or aryloxy group; X is an integer from 1 to 6, nitroso, mercapto, amino, epoxide, vinyl, imide, chloro, m and n are integers from 1 to 6 and the R group is as defined above-( _{S) m C n H 2n -Si-} (R) is selected from ₃ groups.

  Particularly preferred coupling agents are bis (3-triethoxysilylpropyl) tetrasulfide and bis (3-triethoxysilylpropyl) disulfide. The coupling agent is used by itself or as a suitable mixture containing an inert filler (eg carbon black) to facilitate the introduction of the coupling agent into the elastomeric composition. be able to.

  The elastomeric composition according to the invention can be vulcanized using known techniques, in particular using sulfur-based vulcanization systems commonly used for diene elastomeric polymers. For this purpose, a sulfur-based vulcanizing agent is introduced into the composition together with a vulcanization accelerator and an activator after the first stage of the thermochemical treatment. In the second treatment stage, the temperature is generally kept below 120 ° C., preferably below 100 ° C., to prevent undesirable pre-crosslinking phenomena.

  Most advantageously used vulcanizing agents are sulfur, including accelerators and activators well known to those skilled in the art, or molecules containing sulfur (sulfur donors).

Particularly effective activators are zinc compounds, in particular ZnO, ZnCO ₃ , zinc salts of saturated or unsaturated fatty acids containing 8 to 18 carbon atoms, such as zinc stearate, ZnO and fatty acids, and BiO, PbO Pb ₃ O ₄ , PbO ₂ or mixtures thereof are preferably formed in situ into the elastomeric composition.

  Commonly used accelerators are selected from dithiocarbamates, guanidines, thioureas, thiazoles, sulfenamides, thiurams, amines, xanthates, or mixtures thereof.

  The elastomeric composition according to the present invention may include other commonly used additives, selected based on the specific application intended for the composition. For example, an antioxidant, an antioxidant, a plasticizer, an adhesive, an anti-ozone agent, a modified resin, a fiber (eg, Kepler pulp), or a mixture thereof is added to the composition can do.

  In particular, a plasticizer selected from mineral oils, vegetable oils, synthetic lubricating oils or mixtures thereof, such as aromatic oils, naphthenic oils, phthalates, soybean oils, or mixtures thereof, according to the invention, in order to further improve processability. It can be added to the elastomer composition. The amount of plasticizer generally ranges from 2 phr to 100 phr, preferably from 5 phr to 50 phr.

  The elastomeric composition according to the invention can be produced by mixing the polymer components with optional reinforcing fillers and other additives by techniques known in the prior art. For example, an open mill type open mixer, an internal mixer of a type equipped with a tangential rotor (Banbury) or a connected rotor (Intermix), or a Ko-Kneader type (Buss) is used for mixing. Alternatively, it can be carried out in a simultaneous rotating or counter rotating twin screw type continuous mixer.

  The copolymer of ethylene and at least one aliphatic α-olefin (b) can be used in the form of powder, granules or pellets.

  The present invention will be described in more detail with respect to the accompanying FIG. 1 by a number of specific embodiments. FIG. 1 is a cross-sectional view of a portion of a tire manufactured in accordance with the present invention.

  “A” indicates the axial direction, and “r” indicates the radial direction. For clarity, FIG. 1 shows only a portion of the tire, but the other portions not shown are the same and are configured symmetrically with respect to the radial direction “r”.

  The tire (100) includes at least one carcass ply (101) with opposing lateral edges bonded to individual bead wires (102). The carcass ply (101) and the bead wire (102) are joined by folding the opposite side edges of the carcass ply (101) around the bead wire (102), and as shown in FIG. ) Is performed.

  Alternatively, the conventional bead wire (102) replaces a pair of annular inserts that are not stretchable in the circumferential direction and formed from elongated elements arranged in concentric coils (not shown in FIG. 1). (See, for example, European patent applications EP 928 680 and EP 928 702). In this case, the carcass ply (101) is not folded around the annular insert and is joined by a second carcass ply (not shown in FIG. 1) applied to the outside of the first carcass ply.

  The carcass ply (101) generally consists of a plurality of reinforcing cords arranged parallel to each other and at least partially coated with an elastomeric compound. These reinforcing cords are typically textile fibers such as rayon, nylon or polyethylene terephthalate, or steel wires twisted together and coated with an alloy (eg copper / zinc, zinc / manganese, zinc / molybdenum / cobalt alloy, etc.) Manufactured from.

  The rubberized carcass ply (101) is generally of the radial type, i.e. includes reinforcing cords arranged substantially perpendicular to the circumferential direction. Each bead wire (102) is enclosed within a bead (103) defined along an inner circumferential edge of the tire (100). Such beads cause the tire to engage on a rim (not shown in FIG. 1) that forms part of the wheel. Each carcass fold (101a) includes a bead filler (104) in which a bead wire (102) is embedded. The wear resistant strip (105) is generally located at an axially outer position relative to the carcass fold (101a).

  The belt structure (106) is applied along the circumference of the rubberized carcass ply (101). In the particular embodiment of FIG. 1, the belt structure (106) includes two belt strips (106a, 106b) that include a plurality of reinforcing cords, typically metal cords, that are connected to each other within each strip. Parallel and oriented to intersect adjacent strips to form a predetermined angle with respect to the circumferential direction. At least one 0 ° reinforcement layer (106c), commonly known as a “0 ° belt”, can optionally be applied to the radially outermost side of the belt strip (106b). A plurality of reinforcing cords, usually textile cords, which are arranged at an angle of several degrees with respect to the circumferential direction, covered with an elastomeric material and bonded together.

  A side wall (108) is also applied to the outside of the rubberized carcass ply (101), and this side wall extends from the bead (103) to the end of the belt structure (106) at an axially outer position.

  A tread band (109) whose lateral edge is connected to the side wall (108) is applied circumferentially to a position radially outward of the belt structure (106). The tread band (109) manufactured according to the present invention has a rolling surface (109a) designed to contact the ground on the outside. Circumferential grooves connected by a transverse notch (not shown in FIG. 1) and defining a plurality of blocks of various shapes and sizes distributed on the rolling surface (109a) are generally on this rolling surface (109a). Although provided, the rolling surface (109a) is shown as smooth in FIG. 1 for clarity.

  A strip made from an elastomeric material (110), commonly known as a “small sidewall”, may optionally be present in the connection region between the sidewall (108) and the tread band (109). This small side wall is generally obtained by coextrusion with the tread band and can improve the mechanical interaction between the tread band (109) and the side wall (108). Alternatively, the end portion of the side wall (108) directly covers the lateral edge of the tread band (109). A lower layer forming a structure commonly known as “cap and base” (not shown in FIG. 1) with the tread band (109) is optionally placed between the belt structure (106) and the tread band (109). be able to.

  The layer of elastomeric material (111) functions as an “adhesion sheet”, ie it can connect between the tread band (109) and the belt structure (106), this layer being the tread band (109) and the belt. Between the structure (106).

  In the case of tubeless tires, the rubber layer (112), commonly known as the “liner”, provides the necessary impermeability to the inflation air of the tire and is also located radially inward relative to the rubberized carcass ply (101). Is provided.

  The process for producing tires according to the present invention can be carried out using techniques and equipment known in the prior art as described, for example, in EP 199 064, US Pat. No. 4,872,822, US Pat. No. 4,768,937. The method can include at least one stage of producing a green tire and at least one stage of vulcanizing the tire.

  More specifically, a method for manufacturing a tire includes a series of semi-finished products corresponding to each part of the tire (carcass ply, belt structure, bead wire, filler, side wall and tread band) in advance and independently of each other. These semi-finished products are then joined together using a suitable manufacturing machine, including a manufacturing step. Next, in the subsequent vulcanization step, the semi-finished products are joined together to form a monolithic block, ie a finished tire.

  Of course, before the step of manufacturing the semi-finished product, a step of blending and molding various blends constituting the semi-finished product by a conventional technique is performed.

  The green tire thus obtained is passed on to subsequent molding and vulcanization steps. For this purpose, the vulcanization mold used is designed to accommodate the tire to be treated in a molding cavity having a wall, which defines the tire outer surface when the tire is complete. The reverse molding is performed.

  Alternative methods for producing tires or tire parts without using semi-finished products are disclosed, for example, in the above-mentioned patent applications EP 928 680 and EP 928 702.

  The green tire can be molded by introducing a pressurized fluid into a space defined by the inner surface of the tire and pressing the outer surface of the green tire against the wall of the molding cavity. In one of the widely practiced molding methods, a vulcanization chamber made from an elastomeric material and filled with steam and / or another fluid under pressure expands in a tire closed inside the molding cavity. Thus, the green tire is pressed against the inner wall of the molding cavity to obtain a desired molded product. Alternatively, the molding can be performed by shaping a toroidal metal support according to the configuration of the tire inner surface obtained as described above, for example, as described in EP 242 840, without an expanding vulcanization chamber. Thus, this support can be provided inside the tire. The difference in coefficient of thermal expansion between the toroidal metal support and the raw elastomeric material is exploited to obtain a suitable molding pressure.

  At this point, a step of vulcanizing the raw elastomeric material present in the tire is performed. For this reason, the outer wall of the vulcanization mold is placed in contact with the heating fluid (generally steam) so that the outer wall reaches a maximum temperature of approximately 100 ° C. to 230 ° C. At the same time, the tire is heated to the internal vulcanization temperature of the tire with the same pressurized fluid used to compress the tire against the wall of the molding cavity and heated to a maximum temperature of 100 ° C to 250 ° C. The time required to vulcanize the entire mass of the elastomeric material to a sufficient extent can generally vary between 3 and 90 minutes and depends primarily on the tire dimensions. When vulcanization is complete, the tire is removed from the vulcanization mold.

  Although the invention has been illustrated with particular reference to tires, other cross-linked elastomer products that can be produced according to the invention include, for example, conveyor belts, drive belts, or flexible tubing.

  The present invention will be described in detail below with a number of adjustment examples, but the description is merely an example and is not intended to limit the present invention.

Examples 1-4
Production of Elastomer Composition The elastomer composition described in Table 1 was produced as follows (the amount of each component is described in phr).

  All ingredients except sulfur, accelerator and retarder were mixed for about 5 minutes in an internal mixer (Pomini PL1.6 type) (first stage). Immediately after the temperature reached 145 ± 5 ° C., the elastomer composition was discharged. Next, sulfur, accelerator and retarder were added and mixed in an open rotary mixer (second stage).

  The Mooney viscosity ML (1 + 4) at 100 ° C. was measured for the non-crosslinked composition obtained above according to ISO standard 289/1. The results are listed in Table 2.

The following measurements were made on the above elastomer composition examples crosslinked at 151 ° C. for 30 minutes:
Density at 23 ° C. according to ISO standard 2781;
-Static mechanical properties according to ISO standard 37;
-International rubber hardness (IRHD) at 23 ° C according to ISO standard 48

  The results obtained are listed in Table 2.

  Table 2 shows the dynamic mechanical properties measured in the following manner using an Instron dynamic device in traction-compression mode. Cylindrical cross-linked specimens (length = 25 mm, diameter = 14 mm) are pre-compressed until they are 10% longitudinally deformed relative to their original length and pre-determined temperature over the entire test period. (23 ° C. or 70 ° C.), dynamic sine wave distortion was applied at an amplitude of ± 3.33% and a frequency of 100 Hz with respect to the length under preload. The dynamic mechanical properties are represented by values of dynamic elastic modulus (E ') and tan delta (loss factor). As is well known, the tan delta value is determined by the ratio of the viscous modulus (E ") and the elastic modulus (E '), both of which are determined by the above dynamic measurements.

  Finally, the tear resistance is measured according to ISO standard 34 and is expressed as an index in Table 2. The result obtained using the reference composition of Example 1 was set to 100.

  The results in Table 2 show that the cross-linked products obtained from elastomer compositions containing ethylene / 1-octene copolymers according to the present invention (Examples 2 and 3) have good tear resistance. The results are obtained without causing excessive elastomeric composition hardness and without significantly increasing the hysteresis properties of the product.

  Furthermore, the results in Table 2 show that the elastomer composition according to the present invention has a relatively low viscosity value, so that it not only shows better processability and extrudability, but also a relatively low density, In the case of tires for wheels, it is also shown that a relatively lightweight tire having a relatively low rolling resistance can be obtained.

It is sectional drawing of the part of the tire manufactured by this invention.

Claims (51)

A wheel tire comprising at least one component manufactured from a crosslinked elastomeric material, the component comprising:
a) at least one diene elastomeric polymer,
b) At least one copolymer of ethylene, at least one aliphatic α-olefin, and optionally a polyene, having a molecular weight distribution (MWD) index of less than 5 and a melting enthalpy (ΔH _m ) of 30 J / a copolymer characterized by being g or more,
A tire comprising an elastomer composition comprising -A carcass structure with at least one carcass ply shaped substantially in a toroidal configuration, the opposite side edges corresponding to the respective right and left bead wires, each bead wire being in each bead; Surrounded by carcass structure,
A belt structure comprising at least one belt strip applied at a circumferentially outer position relative to the carcass structure;
-A tread band superimposed in a circumferential direction on the belt structure;
A pair of side walls provided on both sides of the carcass structure;
(A) at least one diene elastomer polymer;
(B) at least one copolymer of ethylene, at least one aliphatic α-olefin, and optionally polyene, having a molecular weight distribution (MWD) index of less than 5 and a melting enthalpy (ΔH _m ) of 30 J / a copolymer characterized by being g or more,
The tire according to claim 1, wherein the component including an elastomer composition including a tread band.   The tire according to claim 1 or 2, wherein a molecular weight distribution (MWD) index is 1.5 to 3.5. The tire according to claim 1 or 2, wherein the melting enthalpy (ΔH _m ) is 34 J / g to 130 J / g.   The tire according to any one of the preceding claims, wherein the copolymer of ethylene and at least one aliphatic α-olefin (b) is present in the elastomer composition in an amount of 0.1 phr to 100 phr.   6. Tire according to claim 5, wherein the copolymer of ethylene and at least one aliphatic α-olefin (b) is present in the elastomer composition in an amount of 3 phr to 50 phr.   The tire according to claim 6, wherein the copolymer of ethylene and at least one aliphatic α-olefin (b) is present in the elastomer composition in an amount of 5 phr to 20 phr. In the copolymer (b), the aliphatic α-olefin is an olefin of the formula CH ₂ ═CH—R, wherein R represents a linear or branched alkyl group containing 1 to 12 carbon atoms. The tire according to any one of claims 1 to 7, wherein   The aliphatic α-olefin is selected from propylene, 1-butene, isobutylene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-dodecene, or mixtures thereof. 8. The tire according to 8.   The tire according to claim 9, wherein the aliphatic α-olefin is 1-octene.   The tire according to any one of claims 1 to 10, wherein in the copolymer (b), the polyene is a conjugated or non-conjugated diene, triene or tetraene.   The tire according to claim 11, wherein the polyene is a diene. Copolymers of ethylene with at least one aliphatic α- olefin (b) ^has a density of ^{0.86g / cm 3 ~0.93g / cm 3} , according to any one of claims 1 to 12 tire.   The copolymer of ethylene and at least one aliphatic α-olefin (b) has a melt flow index (MFI) of 0.1 g / 10 min to 35 g / 10 min. Tire described in.   The tire according to any one of claims 1 to 14, wherein the copolymer (b) of ethylene and at least one aliphatic α-olefin has a melting point of 30 ° C or higher.   The copolymer of ethylene and at least one aliphatic α-olefin (b) comprises 50 mol% to 98 mol% ethylene, 2 mol% to 50 mol% aliphatic α-olefin, 0 mol% to 5 mol%. The tire according to any one of claims 1 to 15, which has a polyene composition of:   The copolymer (b) of ethylene and at least one aliphatic α-olefin comprises a functional group selected from a carboxyl group, an anhydride group, an ester group, a silane group, and an epoxide group. The tire according to claim 1.   The tire according to claim 17, wherein the functional group is present in an amount of 0.05 to 50 parts by weight per 100 parts by weight of the copolymer of ethylene and at least one aliphatic α-olefin (b). The tire according to any one of claims 1 to 18, wherein the diene elastomer polymer (a) has a glass transition temperature ( _Tg ) of less than 20C.   Diene elastomeric polymer (a) is cis-1,4-polyisoprene; 3,4-polyisoprene; polybutadiene; optionally halogenated isoprene / isobutene copolymer; 1,3-butadiene / acrylonitrile copolymer; styrene / 1,3 20. Tire according to claim 19, selected from: butadiene copolymers; styrene / isoprene / 1,3-butadiene copolymers; styrene / 1,3-butadiene / acrylonitrile copolymers or mixtures thereof.   21. Tire according to claim 20, wherein the diene elastomeric polymer (a) is functionalized by reaction with a suitable end agent or coupling agent. The elastomer composition is at least one elastomer polymer (c) of at least one monoolefin and an olefin comonomer or derivative thereof, and has a melting enthalpy (ΔH _m ) of less than 15 J / g. The tire according to any one of claims 1 to 21, comprising an elastomeric polymer.   23. A tire according to claim 22, wherein the elastomeric polymer (c) is selected from ethylene / propylene copolymer (EPR) or ethylene / propylene / diene copolymer (EPDM); polyisobutene; butyl rubber; halobutyl rubber; or mixtures thereof.   24. A tire according to claim 23, wherein the elastomeric polymer (c) is functionalized by reaction with a suitable end agent or coupling agent.   25. Tire according to any one of the preceding claims, wherein at least one reinforcing filler is present in the elastomeric composition in an amount of 0.1 phr to 120 phr.   26. A tire according to claim 25, wherein the reinforcing filler is carbon black.   26. A tire according to claim 25, wherein the reinforcing filler is silica.   28. A tire according to claim 27, wherein the elastomeric composition comprises a silica coupling agent. A tread band of a tire for a wheel including a crosslinkable elastomer composition, wherein the crosslinkable elastomer composition is
a) at least one diene elastomeric polymer,
b) At least one copolymer of ethylene, at least one aliphatic α-olefin, and optionally polyene, having a molecular weight distribution (MWD) index of less than 5 and a melting enthalpy (ΔH _m ) of 30 J / g. A copolymer,
Tire tread band including   30. The tread band of claim 29, having a molecular weight distribution (MWD) index of 1.5 to 3.5. Melting enthalpy ([Delta] H _m) is 34J / g~130J / g, a tread band according to claim 29.   32. A tread band according to any one of claims 29 to 31, wherein the copolymer (b) of ethylene and at least one aliphatic [alpha] -olefin is defined in any one of claims 5-18.   33. A tread band according to any one of claims 29 to 32, wherein the diene elastomeric polymer (a) is defined in any one of claims 19 to 21.   34. A tread band according to any one of claims 29 to 33, wherein the elastomeric composition comprises at least one elastomeric polymer (c).   35. A tread band according to claim 34, wherein the elastomeric polymer (c) is defined in any one of claims 22-24.   36. A tread band according to any one of claims 29 to 35, wherein at least one reinforcing filler is present in the elastomeric composition in an amount of 0.1 phr to 120 phr.   37. A tread band according to claim 36, wherein the reinforcing filler is carbon black.   37. A tread band according to claim 36, wherein the reinforcing filler is silica.   40. The tread band of claim 38, wherein the elastomeric composition comprises a silica coupling agent. a) at least one diene elastomeric polymer,
b) At least one copolymer of ethylene, at least one aliphatic α-olefin, and optionally polyene, having a molecular weight distribution (MWD) of less than 5 and a melting enthalpy (ΔH _m ) of 30 J / g or more. A copolymer characterized in that
An elastomer composition comprising:   41. The elastomer composition of claim 40, wherein the molecular weight distribution (MWD) index is 1.5 to 3.5. Melting enthalpy ([Delta] H _m) is 34J / g~130J / g, elastomeric composition of claim 40.   43. Elastomer composition according to any one of claims 40 to 42, wherein the copolymer of ethylene and at least one aliphatic alpha-olefin (b) is defined in any one of claims 5-18. .   44. The elastomer composition according to any one of claims 40 to 43, wherein the diene elastomer polymer (a) is defined in any one of claims 19 to 21.   45. Elastomeric composition according to any one of claims 40 to 44, wherein the elastomeric composition comprises at least one elastomeric polymer (c).   46. Elastomeric composition according to claim 45, wherein the elastomeric polymer (c) is defined in any one of claims 22-24.   47. The elastomeric composition according to any one of claims 40 to 46, wherein the at least one reinforcing filler is present in an amount of 0.1 phr to 120 phr.   48. The elastomer composition of claim 47, wherein the reinforcing filler is carbon black.   49. The elastomeric composition of claim 48, wherein the reinforcing filler is silica.   50. The elastomer composition of claim 49, wherein the elastomer composition comprises a silica coupling agent.   A cross-linked elastomer product obtained by cross-linking the elastomer composition defined in any one of claims 40 to 50.

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