JP6957126B2 - Rubber composition based on silicone oil - Google Patents

Description

The field of the present invention is the field of rubber compositions for tires, or more precisely, rubber compositions for tire treads.

Citation list

It is known that some parts of a tire use a rubber composition that exhibits high rigidity during a small strain (see Patent Document 1). Resistance to small strains corresponds to road behavior, which is an important feature of tires.

This rigidity can be obtained by increasing the content of the reinforcing filler or by incorporating a specific reinforcing resin into the constituent rubber composition of the tire component.

International Publication No. 2013/08787 Pamphlet

However, increasing the stiffness of the rubber composition by increasing the filler content in a known manner may be detrimental to the hysteresis characteristics and thus the rolling resistance characteristics of the tire. Therefore, for economic and environmental purposes, it is a continuous goal to reduce the rolling resistance of tires in order to reduce fuel consumption.

During these studies, the inventor discovered a particular rubber composition that allows for an unexpectedly improved balance of performance between road behavior and tire rolling resistance.

In this description, all percentages shown are mass percent (% by mass) unless otherwise stated.

The expression "elastomer matrix" is understood to mean all elastomers present in said rubber composition in a given composition.

The abbreviation "phr" means parts by weight per 100 parts by weight of the elastomer matrix in the rubber composition considered.

In this description, unless otherwise specified, each Tg _DSC (glass transition temperature) is measured by a known method by DSC (Differential Scan Calorimetry) according to Standard ASTM D3418-08.

Any interval between values represented by the expression "between a and b" represents a range of values greater than "a" and less than "b" (ie, excluding the limitations a and b), but from "a". Any interval between values represented by the expression "up to b" means a range of values from "a" to "b" (ie, including the exact limitations a and b).

The expression "based on" should be understood in the present application to mean a composition comprising a mixture of various components used and / or the product of the reaction, at least in part. Some of the components can or are intended to react together between the various manufacturing stages, especially during vulcanization (curing).

The first aspect of the present invention is a first diene elastomer of 10 to 100 phr having at least one SiOR functional group, wherein R is a hydrogen atom or a hydrocarbon group, and optionally a first diene elastomer. An elastomer matrix comprising a second diene elastomer of 0 to 90 phr different from, which means that it does not contain a second diene elastomer, or at most contains a second diene elastomer of 90 phr, and at least A rubber composition based at least on a reinforced filler containing a reinforced inorganic filler of 60 phr and a plasticizing agent containing a mercapto-modified silicone oil of more than 4 phr.

Advantageous Effects of the Invention A particular rubber composition can improve the performance balance between road behavior and tire rolling resistance, as represented by low strain stiffness and hysteresis.

Unless otherwise stated, the following aspects, embodiments, and modifications, including each of the preferred scope and / or matter, are, respectively, in any one of the other embodiments, other embodiments, and other modifications of the invention. Can be applied.

A "diene" type elastomer (or loosely "rubber", the two terms being considered synonymous) is at least partially from a diene monomer (a monomer having two conjugated or non-conjugated carbon-carbon double bonds). It is understood in a manner known as an elastomer (ie, homopolymer or copolymer) that is derived (meaning one or more).

These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". In general, the expression "essentially unsaturated" means a diene elastomer that results at least partially from a conjugated diene monomer having a content of diene-derived units (conjugated diene) greater than 15% (mol%). It is understood and therefore diene elastomers such as butyl rubber or EPDM type diene / α-olefin copolymers do not meet the above definitions and are particularly "essentially saturated" diene elastomers (low content of diene-derived units). Or it can be specifically described as very low, always less than 15%). In the category of "essentially unsaturated" diene elastomers, the expression "highly unsaturated" diene elastomer means a diene elastomer having a content of diene-derived units (conjugated diene) of more than 50% in particular. Understood.

Although this applies to all types of diene elastomers, those skilled in the art of tires will appreciate that the present invention is preferably used with essentially unsaturated diene elastomers.

Given these definitions, the expression diene elastomer that can be used in the compositions according to the invention is particularly:
(A) Any homopolymer obtained by polymerization of the -conjugated diene monomer, preferably having 4-12 carbon atoms.
(B)-It is understood to mean any copolymer obtained by copolymerizing one or more conjugated diene with each other, or preferably with one or more vinyl aromatic compounds having 8 to 20 carbon atoms.

The following are particularly suitable as the conjugated diene 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di _(C 1 -C ₅ alkyl) -1,3-butadiene, e.g., 2, 3-Dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene or 2-methyl-3-isopropyl-1,3-butadiene, Aryl-1,3-butadiene, 1,3-pentadiene or 2,4-hexadiene and the like. For example, the following are suitable as vinyl aromatic compounds: styrene, ortho-, meta- or para-methylstyrene, "vinyltoluene" commercial mixture, para- (tert-butyl) styrene, methoxystyrene, chlorostyrene, vinylmesitylene. , Divinylbenzene or vinylnaphthalene.

The first diene elastomer can be selected from the group consisting of polybutadiene (BR), synthetic polyisoprene (IR), natural rubber (NR), butadiene copolymers, isoprene copolymers and mixtures thereof, such copolymers. , More preferably selected from the group consisting of butadiene-styrene copolymers (SBRs) and mixtures thereof.

The first diene elastomer may have any microstructure that depends on the polymerization conditions used, in particular the presence or absence of a denaturant and / or randomizer, and the amount of denaturant and / or randomizer used. .. The elastomer can be, for example, a block, statistical, continuous, or microsequential elastomer and can be prepared in a dispersion or solution.

The first diene elastomer has at least one SiOR functional group, where R is a hydrogen atom or a hydrocarbon group.

The expression "hydrocarbon group" means a monovalent group consisting essentially of a carbon atom and a hydrogen atom. Such groups can contain at least one heteroatom, and the aggregate formed by the carbon and hydrogen atoms is known to represent a major fraction of a hydrocarbon group, eg, alkyl or alkoxyalkyl. , Preferably, the aggregate formed by the carbon and hydrogen atoms represents the entire hydrocarbon group, eg, alkyl. Such SiORs (where R is alkyl or alkoxyalkyl) are referred to as "alkoxysilane" functional groups. On the other hand, SiOH (R is a hydrogen atom) is called a "silanol" functional group.

In general, the functional groups of the elastomer, especially the diene elastomer, may or may not be located at the end of the elastomer chain, i.e. away from the end of the chain. The first case occurs, for example, when a diene elastomer is prepared using a polymerization initiator having a functional group or using a functionalizing agent. The second case occurs, for example, when the diene elastomer is modified by the use of a coupling agent or a stellate branching agent having a functional group.

In a second aspect of the present invention, the first diene elastomer is a styrene-butadiene copolymer (SBR), preferably a solution styrene-butadiene copolymer, which is a copolymer of butadiene and styrene prepared in solution. It is a rubber composition according to an embodiment.

A third aspect of the present invention is the rubber composition according to the first or second aspect, in which the SiOR functional group is located at the end of the first diene elastomer chain.

According to a preferred embodiment of the third aspect, the first diene elastomer having a SiOR functional group located at the end of the chain is, for example, hexamethylcyclotri according to the procedure described in European Patent No. 07783311B1. It can be prepared by the reaction of the carbanion with the siloxane at the end of the living elastomer chain, followed by the reaction with the proton donor.

A fourth aspect of the present invention is a rubber composition according to the first or second aspect, in which the SiOR functional group is not located at the end of the first diene elastomer chain.

According to the first modification of the fourth aspect, the SiOR functional group contained in the first diene elastomer can be a pendant group, wherein the silicon atom of the SiOR functional group is the carbon of the elastomer chain of the first diene elastomer. -Equivalent to saying that it may not be inserted between carbon bonds. The diene elastomer having a pendant SiOR functional group can be prepared, for example, by hydrosilylating the elastomer chain with a silane having an alkoxysilane group, followed by hydrolysis of the alkoxysilane functional group to obtain a SiOR functional group.

According to the second modification of the fourth aspect, the SiOR functional group of the first diene elastomer may not be a pendant group, but can be located within the elastomer chain, i.e., within the elastomer chain. This is equivalent to saying that the silicon atom of the SiOR functional group can be inserted between the carbon-carbon bonds of the elastomer chain of the first diene elastomer. Such diene elastomers can be prepared according to the procedure described in European Patent No. 2285552B1. This second variant is preferred and applies to the fourth aspect.

A fifth aspect of the present invention is the rubber composition according to any one of the first to fourth aspects, wherein the first diene elastomer is at least one amine functional group, preferably at least one tertiary. It also has an amine functional group.

According to a preferred embodiment of the fifth aspect, the amine functional group of the first diene elastomer can be a tertiary amine functional group. Examples of the tertiary amine functional group include amines _{substituted with C 1 to} C ₁₀ alkyl groups, preferably C _{1 to} C ₄ alkyls, and more preferably methyl or ethyl groups.

According to this embodiment or the preferred embodiment of the fifth aspect, the amine functional group of the first diene elastomer can be a pendant group. The position of the amine functional group pendant means that the nitrogen atom of the amine functional group may not be inserted between the carbon-carbon bonds of the elastomer chain of the first diene elastomer in a known manner.

A sixth aspect of the present invention is the rubber composition according to the fifth aspect, in which the SiOR functional group has an amine functional group.

Such a diene elastomer can result from modification of the diene elastomer with a coupling agent that introduces an alkoxysilane group having an amine functional group into the elastomer chain according to the operating procedure described in European Patent No. 2285852B1. The following are suitable, for example, as coupling agents: N, N-dialkylaminopropyltrialkoxysilane, C _{1 to} C ₁₀ , preferably C _{1 to} C ₄ , dialkyl groups, compound 3- (N, N-dimethylaminopropyl). ) Trimethoxysilane, 3- (N, N-dimethylaminopropyl) triethoxysilane, 3- (N, N-diethylaminopropyl) trimethoxysilane, 3- (N, N-diethylaminopropyl) triethoxysilane Most particularly preferred regardless of embodiments of the invention.

A seventh aspect of the present invention is the rubber composition according to any one of the first to sixth aspects, wherein R of the SiOR functional group is a hydrogen atom.

An eighth aspect of the present invention is the rubber composition according to any one of the first to sixth aspects, wherein R of the SiOR functional group is a hydrocarbon group.

According to a preferred embodiment of the eighth aspect, the hydrocarbon group is an alkyl group, preferably an alkyl group having 1 to 12 carbon atoms, more preferably 1 to 12 carbon atoms, even more preferably 1 to 6. It can be a branched, linear or cyclic alkyl group having a carbon atom of, particularly 1-4 carbon atoms, more particularly a methyl or ethyl group.

A ninth aspect of the present invention is a glass in which the first diene elastomer is less than −40 ° C. (particularly −100 ° C. to −40 ° C.), preferably less than −45 ° C. (particularly −90 ° C. to −45 ° C.). The rubber composition according to any one of the first to eighth aspects, which has a transition temperature (Tg _DSC).

According to a preferred embodiment of the invention, the elastomer matrix is 20-100 phr, preferably 30-100 phr, more preferably 40-100 phr, even more preferably 50-100 phr, especially 60-100 phr, more particularly 70-100 phr, More particularly with the first diene elastomer of 70-90 phr, 0-80 phr, preferably 0-70 phr, more preferably 0-60 phr, even more preferably 0-50 phr, especially 0-40 phr, even more particularly 0-30 phr. In particular, it may include a second diene elastomer of 10 to 30 phr.

According to a preferred embodiment of the invention, the elastomer matrix is 10 to 90 phr, preferably 10 to 80 phr, more preferably 10 to 70 phr, even more preferably 10 to 60 phr, especially 10 to 50 phr, more particularly 10 to 40 phr. More particularly with the first diene elastomer of 10-30 phr, 10-90 phr, preferably 20-90 phr, more preferably 30-90 phr, even more preferably 40-90 phr, especially 50-90 phr, even more particularly 60-90 phr. In particular, it may include a second diene elastomer of 70-90 phr.

A tenth aspect of the present invention is a tenth aspect in which the second diene elastomer is selected from the group consisting of polybutadiene, natural rubber, synthetic polyisoprene, butadiene copolymer, isoprene copolymer, and a mixture thereof. The rubber composition according to any one of the above.

An eleventh aspect of the present invention is a rubber composition according to a tenth aspect, wherein the second diene elastomer is polybutadiene.

The rubber composition according to the present invention is based on a reinforced filler.

The reinforced filler may include a reinforced inorganic filler (eg silica), carbon black or a mixture thereof.

The reinforcing filler in the rubber composition according to the present invention comprises at least 60 phr, preferably at least 70 phr, more preferably at least 80 phr, even more preferably at least 90 phr, particularly at least 100 phr.

In a twelfth aspect of the present invention, the reinforcing filler is a reinforcing inorganic filler having a reinforcing filler of 60 to 200 phr, preferably 70 to 180 phr, more preferably 80 to 160 phr, even more preferably at least 90 to 140 phr, particularly 100 to 120 phr. The rubber composition according to any one of the first to eleventh aspects, including the rubber composition.

The expression "reinforced inorganic filler" is used herein to refer to its color and its origin (natural or synthetic), also referred to as "white filler", "transparent filler", or even "non-black filler". Regardless, it should be understood to mean any inorganic or mineral filler, intended for the manufacture of tires by itself, in contrast to carbon black, without any means other than intermediate coupling agents. The rubber composition can be fortified, in other words, in the role of fortification, it can replace conventional tire-grade carbon black, such fillers are generally hydrolyzed on their surface in a known manner. It is characterized by the presence of a (-OH) group.

The physical condition in the presence of this filler is not important whether it is in powder, microbeads, granules, bead morphology, or other suitable densified form. Of course, a mixture of various reinforced inorganic fillers, preferably a mixture of highly dispersible siliceous and / or alumina fillers, will be described below.

Mineral fillers of siliceous type, preferably silica (SiO ₂ ) and / or alumina type, preferably alumina (Al ₂ O ₃ ) are particularly suitable as reinforced inorganic fillers.

In the thirteenth aspect of the present invention, the reinforced inorganic filler mainly contains silica, that is, the reinforced inorganic filler contains more than 50% by mass of silica per 100% by mass of the reinforced inorganic filler, the first to twelfth aspects. The rubber composition according to any one of the above aspects. Preferably, the reinforced inorganic filler may contain 100% by weight of silica per 100% by weight of the reinforced inorganic filler. The second rubber composition can be based on a type of silica or a blend of several silicas. The silica used may be any reinforcing silica known to those skilled in the art, both 450m less than ² / g, preferably any precipitated silica having a BET surface area and a CTAB specific surface area is 20 to 400 m ² / g Alternatively, it can be thermally decomposed silica. Such silica may or may not be covered. Elkem Silicon Materials' Sidestar R300 is mentioned as a low specific surface area silica. Examples of highly dispersible precipitated silica (“HDS”) include Evonik's “Ultrasil 7000” and “Ultrasil 7005”, Rhodia's “Zeosil 1165 MP”, “Zeosil 1135 MP” and “Zeosil 1115 MP”, and PPG “Zeosil 1115 MP”. Examples thereof include Hi-Sil EZ150G, Huber's "Zeopol 8715", "Zeopol 8745" and "Zeopol 8755", or silica having a high specific surface area as described in WO 03/016387. Examples of the exothermic silica include Cabot's "CAB-O-SIL S-17D", Wacker's "HDK T40", Evonik's "Aeropel 300/30", "Aerosil 380", "Aerosil 150", or "Aerosil". 90 ”. Such silica can be covered, for example, "CAB-O-SIL TS-530" covered with Cabot's hexamethyldiasilazene, or "CAB-O-SIL TS" covered with dimethyldichlorosilane. -622 "and so on.

Especially when it is silica, reinforcing inorganic filler used is advantageously 50~350m ² / g, and more preferably 100 to 300 m ² / g, still more preferably 150 to 250 ² / g BET surface area and the It has a CTAB specific surface area.

The BET surface area is determined according to a known method, that is, "The Journal of the American Chemical Society", Vol. 60, page 309, Pressure 1938, more specifically, December 1996 French standard NF ISO 9277 (multipoint volumetric method (5 points), gas: nitrogen, degassing: 1 hour at 160 ° C., relative Measured by gas adsorption using the Brunauer-Emmett-Teller method according to the pressure range p / po: 0.05 to 0.17). The CTAB specific surface area is determined according to the French standard NF T 45-007 (Method B) of November 1987.

Those skilled in the art have found that reinforcing fillers of another property, especially organic properties such as carbon black, are such that the reinforcing filler is covered with an inorganic layer such as silica, or contains functional group sites, especially hydroxyl groups, on its surface. It will be appreciated that if the use of a coupling agent is required to form a connection between the filler and the elastomer, it can be used as a filler equivalent to the reinforced inorganic filler described in this section. Examples include carbon black for tires as described in International Publication No. 96/37547 and International Publication No. 99/28380.

In the fourteenth aspect of the present invention, the reinforcing filler is less than 40 phr (for example, 0.5 to 40 phr), preferably less than 30 phr (for example, 1.0 to 30 phr), and more preferably less than 20 phr (for example, 1. The rubber composition according to any one of the first to thirteenth aspects, which comprises 5 to 20 phr), and even more preferably less than 10 phr (for example, 2 to 10 phr) of carbon black.

Within the range shown, the typical performance provided by the reinforced inorganic filler, i.e. the coloring properties (black pigment) and anti-UV properties of carbon black without further adversely affecting the low hysteresis (reduced rolling resistance). There are advantages.

Chemical and / or physical properties between the reinforced inorganic filler (the surface of its particles) and the elastomer matrix, eg, a diene elastomer, to bond the reinforced inorganic filler to an elastomer matrix, eg, a diene elastomer. Coupling agents (or binders) intended to provide sufficient ligation can be used in known methods. This coupling agent is at least bifunctional. In particular, at least bifunctional organosilanes or polyorganosiloxanes can be used.

For example, as described in International Publication No. 03/002648, International Publication No. 03/002649 and International Publication No. 2004/033548, "symmetrical" or "asymmetrical" depending on the particular structure. Silane polysulfides called can be particularly used.

式中、
−非置換の又は置換された、互いに同一又は異なるＲ^１基は、Ｃ_１〜Ｃ_１８アルキル、Ｃ_５〜Ｃ_１８シクロアルキル又はＣ_６〜Ｃ_１８アリール基（好ましくは、Ｃ_１〜Ｃ_６アルキル、シクロヘキシル又はフェニル基、特にＣ_１〜Ｃ_４アルキル基、より特にメチル及び／又はエチル）を表し、
−非置換の又は置換された、互いに同一又は異なるＲ^２基は、Ｃ_１〜Ｃ_１８アルコキシル又はＣ_５〜Ｃ_１８シクロアルコキシル基（好ましくはＣ_１〜Ｃ_８アルコキシル及びＣ_５〜Ｃ_８シクロアルコキシルから選択される基、より好ましくはＣ_１〜Ｃ_４アルコキシル、特にメトキシル及びエトキシルから選択される基）を表し、上記の定義を限定することなく特に適切である。 Particularly suitable silane polysulfides correspond to the following general formula (I):
(I) ZA-Sx-AZ,
During the ceremony
−X is an integer of 2 to 8 (preferably 2 to 5).
−A is a divalent hydrocarbon group (preferably C _{1 to} C ₁₈ alkylene group or C _{6 to} C ₁₂ arylene group, more particularly C _{1 to} C ₁₀ , especially C _{1 to} C ₄ , alkylene, especially. propylene),
-Z corresponds to one of the following equations:

During the ceremony
^{-Unsubstituted or substituted R 1} groups that are the same or different from each other are C _{1 to} C ₁₈ alkyl, C _{5 to} C ₁₈ cycloalkyl or C _{6 to} C ₁₈ aryl groups (preferably C _{1 to} C ₆ alkyl). , cyclohexyl or phenyl group, especially _C 1 -C ₄ alkyl group, more particularly a methyl and / or ethyl),
- unsubstituted or substituted, the same or different ^{R 2} groups _together, C 1 _{-C 18} alkoxyl or _C 5 _{-C 18} cycloalkoxyl group (preferably _C 1 -C ₈ alkoxyl and _C 5 -C ₈ cydoalkoxyl group selected from, more preferably C ₁ -C ₄ alkoxyl, especially a group) selected from methoxyl and ethoxyl, particularly suitable without limiting the definition above.

In the case of a mixture of alkoxysilane polysulfides corresponding to the above formula (I), particularly a conventional commercially available mixture, the average value of the "x" index is small, preferably 2 to 5, more preferably about 4. However, the present invention can also be advantageously carried out with, for example, alkoxysilane disulfide (x = 2).

More particularly, examples of polysulfide, for example, bis (3-trimethoxysilylpropyl) or bis (3-triethoxysilylpropyl) polysulfide, bis _((C 1 -C ₄₎ alkoxyl _(C 1 -C ₄ ) alkylsilyl (C 1 _{-C 4)} alkyl) polysulfide (especially disulfides, trisulfide or tetrasulfide compounds) are exemplified. Among these compounds, in particular, bis (3-triethoxysilylpropyl) tetrasulfide, abbreviated as TESPT _{, of the formula [(C 2} H ₅ O) ₃ Si (CH ₂ ) ₃ S ₂ ] _{2, or the formula.} [(C ₂ HSO) ₃ Si (CH ₂ ) ₃ S] ₂ bis (3-triethoxysilylpropyl) disulfide, abbreviated as TESPD, is used. Further, as a preferable example, as described in International Publication No. 02/083728 (or US Pat. No. 7,217,751), bis (mono (C _{1 to} C ₄ ) alkoxylurgi (C _{1 to} C ₄ )) Alkoxysilylpropyl) polysulfides (particularly disulfides, trisulfides or tetrasulfides), more particularly bis (monoethoxydimethylsilylpropyl) tetrasulfides.

In particular, as coupling agents other than alkoxysilane polysulfide, International Publication No. 02/30939 (or US Patent No. 6774255) and International Publication No. 02/31041 (or US Patent Application Publication No. 2004/051210) as described in the specification), bifunctional POS ^R 2 = OH the (polyorganosiloxane) or hydroxy polysulfide (the above formula (I)), or, for example, WO 2006/125532 pamphlet, Silanes or POSs having an azodicarbonyl functional group as described in WO 2006/125533 and WO 2006/125534 can be mentioned.

Examples of other silane sulfides include, for example, US Pat. No. 6,849,754, International Publication No. 99/09036, International Publication No. 2006/023815, International Publication No. 2007/0988080, International Publication No. 2008/ Silanes with at least one thiol (-SH) functional group (called mercaptosilane) and / or at least one blocked thiol functional group, as described in Pamphlet 055986 and Pamphlet 2010/072685. Can be mentioned.

Of course, a mixture of the above-mentioned coupling agents, as specifically described in the above-mentioned International Publication No. 2006/125534 pamphlet, can also be used.

According to one preferred embodiment of the invention, the content of the coupling agent can be 0.5-15% by weight per 100% by weight of the reinforced inorganic filler, especially silica.

According to one preferred embodiment of the invention, the content of the coupling agent is less than 30 phr (eg 0.1-30 phr), preferably less than 25 phr (eg 0.5-25 phr), more preferably less than 20 phr. It can be (eg, 1 to 20 phr), and even more preferably less than 15 phr (eg, 1.5 to 15 phr).

The rubber composition according to the present invention is based on a plasticizer.

The plasticizer may include a liquid plasticizer, a hydrocarbon resin, or a mixture thereof.

According to a preferred embodiment of the present invention, the total plasticizer content is 20-100 phr, preferably 25-90 phr, more preferably 30-80 phr.

The plasticizer in the rubber composition according to the present invention contains more than 4 phr of mercapto-modified silicone oil, which is one of the liquid plasticizers. Below the indicated minimum values, the targeted technical effect is inadequate. Preferably, the content of the mercapto-modified silicone oil is at least 6 phr, more preferably at least 8 phr, even more preferably at least 10 phr. Mercapto-modified silicone oils are liquids at 20 ° C. (under atmospheric pressure) by definition.

The mercapto-modified silicone oil means a silicone or a polymerized siloxane having at least one mercapto (thiol: -SH) functional group per molecule.

According to a preferred embodiment of the present invention, the mass average molecular weight (Mw) of the mercapto-modified silicone oil is more than 500 g / mol (for example, 500 to 50,000 g / mol), preferably more than 1000 g / mol (for example, 1000 to 40,000 g / mol). Mole), more preferably over 3000 g / mol (eg 3000-30000 g / mol), even more preferably at least 5000 g / mol (eg 5000-20000 g / mol). The mass average molecular weight of mercapto-modified silicone oil is 0 in gel permeation chromatography (ambient temperature (eg 20 ° C.), polystyrene standard, μ styragem column, eluent THF (tetrahydrofuran), flow rate 1 mm / min, THF. It can be determined by injecting 200 μl (microliter) of a solution containing 5.5% by mass of silicone and performing detection with a "differential refractometer" and a "ultrahydrofuran and visible absorption spectrophotometer").

A fifteenth aspect of the present invention is the rubber composition according to any one of the first to fourth aspects, wherein the mercapto-modified silicone oil has at least two mercapto functional groups per molecule.

According to a preferred embodiment of the present invention, the functional type of the mercapto-modified silicone oil is selected from the group consisting of side chains, terminal chains, and double ends which are α, ω bifunctional types.

A sixteenth aspect of the present invention is the rubber composition according to any one of the first to fifteenth aspects, wherein the functional type of the mercapto-modified silicone oil is an α or ω bifunctional type.

Metcapto-modified silicone oils are well known and commercially available, for example, Shin-Etsu Chemical Co., Ltd. , Ltd. Known as KF-2001, KF-2004, and X-22-167B provided by.

A seventeenth aspect of the present invention is the rubber composition according to any one of the first to sixth aspects, wherein the plasticizer contains a mercapto-modified silicone oil of 4 to 40 phr. At the recommended maximum, there are issues with the cost of mercapto-modified silicone oil and the risk of degrading workability. Preferably, the content of the mercapto-modified silicone oil is 6 to 30 phr, more preferably 8 to 20 phr, and even more preferably 10 to 15 phr.

The eighteenth aspect of the present invention further comprises a compound selected from the group consisting of at least one liquid plasticizer other than mercapto-modified silicone oil, at least one hydrocarbon resin and a mixture thereof. The rubber composition according to any one of the seventeenth aspects.

The role of the liquid plasticizer is to soften the matrix by diluting the elastomer and the reinforced filler. Liquid plasticizers are liquid at 20 ° C. by definition and their role is to soften the matrix by diluting elastomers and reinforcement fillers, the Tg _{DSC of which} is less than -20 ° C., preferably by definition. It is less than -30 ° C and less than -40 ° C.

Any liquid plasticizer (eg, a diene elastomer) known for its plasticizing properties with respect to any extender oil, elastomer matrix, whether aromatic or non-aromatic, can be used as the liquid plasticizer. At ambient temperature (20 ° C) under atmospheric pressure, these plasticizers or their oils are of a hydrocarbon resin that is somewhat viscous but is essentially solid at ambient temperature (20 ° C) under atmospheric pressure. In contrast to plasticization, it is a liquid (ie, a substance that, as a reminder, has the ability to ultimately take the shape of a container).

In the nineteenth aspect of the present invention, liquid plasticizers other than mercapto-modified silicone oil are liquid diene polymers, polyolefin oils, naphthenic oils, paraffin oils, distillate aromatic extract (DAE) oils, and medium-extracted solvent-containing products. MES) Oil, Treated Distillate Aromatic Extract (TDAE) Oil, Residual Aromatic Extract (RAE) Oil, Treated Residual Aromatic Extract (TRAE) Oil, Safe Residual Aromatic Extract (SRAE) Oil, Selected from the group consisting of mineral oils, vegetable oils, ether plasticizers, ester plasticizers, phosphoric acid plasticizers, sulfonic acid plasticizers, and mixtures thereof, preferably MES oils, TDAE oils, naphthenic oils, vegetable oils and their mixtures. A rubber composition according to an eighteenth aspect, selected from the group consisting of mixtures, more preferably selected from the group consisting of MES oils, vegetable oils and mixtures thereof, and even more preferably selected from the group consisting of vegetable oils and mixtures thereof. It is a thing. Vegetable oils include flaxseed oil, benivana oil, soybean oil, corn oil, cotton seed oil, cub seed oil, sunflower oil, tung oil, pine oil, sunflower oil, palm oil, olive oil, coconut oil, peanut oil and grape seed oil, and mixtures thereof. , Especially sunflower oil, more particularly above 60% by mass, even more particularly above 70% by mass, preferably over 80% by mass, more preferably over 90% by mass, even more preferably over 100% by mass of oleic acid. It may consist of an oil selected from the group consisting of sunflower oil.

Hydrocarbon resins are polymers well known to those skilled in the art that are essentially based on carbon and hydrogen and are therefore inherently miscible with rubber compositions such as diene elastomer compositions. Also, the hydrocarbon resin can be based on an aliphatic or aromatic, or even an aliphatic / aromatic type, i.e. an aliphatic and / or aromatic monomer. The hydrocarbon resin can be natural or synthetic and may or may not be petroleum-based (if so, it is also known as the petroleum resin name). Hydrocarbon resins are preferably exclusively hydrocarbons, i.e. they contain only carbon and hydrogen atoms.

Preferably, the "plasticized" hydrocarbon resin exhibits at least one, more preferably all of the following properties:
_{Tg DSC above} -20 ° C (eg 20 ° C-100 ° C), preferably above 30 ° C (eg 30 ° C-100 ° C), more preferably above 40 ° C (eg 40 ° C-100 ° C),
-400-2000 g / mol (more preferably 500-1500 g / mol) number average molecular weight (Mn),
Polydispersity index (PI) less than -3, more preferably less than 2 (Note: PI = Mw / Mn, Mw is mass average molecular weight).

The macrostructure (Mw, Mn, PI) of the hydrocarbon resin is determined by steric exclusion chromatography (SEC): solvent tetrahydrofuran, temperature 35 ° C., concentration 1 g / l, flow rate 1 ml / min, 0.45 μm prior to injection. Filtered solution of porosity, Moore correction using polystyrene standard, set of three "Waters" columns in series ("Waters" HR4E, HR1, and HR0.5), differential refractometer ("Waters" Detection by 2410 ") and its associated operating software ("Waters Emper ").

In a twentieth aspect of the present invention, the hydrocarbon resin is a cyclopentadiene (abbreviated as CPD) homopolymer or copolymer resin, a dicyclopentadiene (abbreviated as DCPD) homopolymer or copolymer resin, a terpen homopolymer or copolymer. resins, C ₅ fraction homopolymer or copolymer resins, C ₉ fraction homopolymer or copolymer resins, is selected from the group consisting of α- methylstyrene homopolymer or copolymer resins, and mixtures thereof, the rubber composition according to the eighteenth aspect It is a thing. Among the above copolymer resins, (D) CPD / vinyl aromatic copolymer resin, (D) CPD / terpen copolymer resin, (D) CPD / C ₅ fraction copolymer resin, (D) CPD / C ₉ fraction copolymer resin, terpene / vinylaromatic copolymer resins, terpene / phenol copolymer resins, C ₅ fraction / vinylaromatic copolymer resins, C ₉ fraction / vinylaromatic copolymer resins, and uses those selected from the group consisting of mixtures It is more preferable to do so.

The term "terpene" is a combination of α-pinene, β-pinene, and limonene monomers in a known manner herein, preferably using a limonene monomer, which is a known method. And there are three possible isomers: L-limonene (left-handed enantiomer), D-limonene (right-handed enantiomer), or dipentene, which is the racemic form of right-handed and left-handed enantiomers. Styrene, α-methylstyrene, ortho-, meta-, or para-methylstyrene, vinyltoluene, para- (tert-butyl) styrene, methoxystyrene, chlorostyrene, hydroxystyrene, vinylmethylene, divinylbenzene, vinylnaphthalene, or Any vinyl aromatic monomer obtained from the C ₉ distillate (or more generally from the C _{8 to} C ₁₀ distillates) is suitable, for example, as a vinyl aromatic monomer. Preferably, the vinyl aromatic compound is a vinyl aromatic monomer obtained from _{a styrene or C 9} distillate (or more generally from a C _{8 to} C _{10 distillate).} Preferably, the vinyl aromatic compound is a small amount of monomer represented as a mole fraction in the copolymer under consideration.

The above preferred resins are well known to those of skill in the art, for example:
-Polylimonene resin: From DRT under the name of "Decorite L120" (Mn = 625 g / mol, Mw = 1010 g / mol, PI = 1.6, Tg _DSC = 72 ° C.) or "Sylvagum TR7125C" (Mn = 630 g / mol) , Mw = 950 g / mol, PI = 1.5, Tg _DSC = 70 ° C.) from Arizona Chemical Company.
-C ₅ fraction / vinyl aromatic, especially C ₅ fraction / styrene or C ₅ fraction / C ₉ fraction, copolymer resin: names of "Super Nevtac 78", "Super Nevtac 85" or "Super Nevtac 99" From the Neverle Chemical Company, from Goodear Chemicals under the name "Wingtack Extra", from Kolon under the names "Hikorez T1095" and "Hikorez T1100", or from Kolon under the names "Escorez 2101" and "Escorez 2101"
Limonene / Styrene Copolymer Resin: Commercially available from DRT under the name "Decorite TS 105" or from Arizona Chemical Company under the names "ZT115LT" and "ZT5100".

Moreover, as an example of another preferable resin, a phenol-modified α-methylstyrene resin can be mentioned. It should be remembered that in order to characterize these phenolic modified resins, a value called "hydroxyl value" (measured according to standard ISO 4326 and expressed in mg KOH / g) is used by known methods. There is. α-Methylstyrene resins, especially those modified with phenol, are well known to those skilled in the art and are commercially available, for example, "Sylvares SA 100" (Mn = 660 g / mol, PI = 1.5, Tg _DSC = 53 ° C. ), "Sylvares SA 120" (Mn = 1030 g / mol, PI = 1.9, Tg _DSC = 64 ° C.), "Sylvares 540" (Mn = 620 g / mol, PI = 1.3, Tg _DSC = 36 ° C., Sold by Arizona Chemical Company under the names of hydroxyl value = 56 mg KOH / g) and "Sylvares 600" (Mn = 850 g / mol, PI = 1.4, Tg _DSC = 50 ° C., hydroxyl value = 31 mg KOH / g). ing.

The rubber composition according to the present invention is, for example, an elastomer wax, a chemical ozone deterioration inhibitor, an antioxidant, a reinforcing resin, a methylene acceptor (for example, phenol novolac resin) or a methylene donor (for example, HMT or H3M). Intended to manufacture tires, especially tire treads, such as protective agents such as, sulfur or donors of sulfur and / or cross-linking systems based on peroxides and / or bismaleimides, vulcanization accelerators, or vulcanization activators. It can be based on all or part of the usual additives commonly used in elastomer compositions.

Also, these compositions can be used to disperse the coupling activator when a coupling agent is used, the agent for coating the reinforced inorganic filler, or more generally the filler in the rubber matrix. Improvements and reductions in the viscosity of the composition can be based on processing aids that can improve processing properties in the unprocessed state by known methods, such as alkylalkoxysilanes, polyols, polyethers, etc. Hydrolyzable silanes such as amines, or hydroxylated or hydrolyzable polyorganosiloxanes.

The rubber composition according to the invention can be produced in a suitable mixer using two consecutive preparation steps well known to those skilled in the art: up to a maximum temperature of 110 ° C. to 190 ° C., preferably 130 ° C. to 180 ° C. First stage of thermal machining or kneading at high temperature (referred to as "non-productive" stage) and subsequent machining at low temperatures, typically below 110 ° C, for example 40 ° C-100 ° C. Two stages (called "productive" stages) and a finishing stage during which the cross-linking or vulcanization system is incorporated.

The processes that can be used in the production of such compositions are, for example, preferably the following steps:
-During the first stage (the "non-productive" stage), the reinforcing filler is incorporated into the elastomer matrix, eg diene elastomer, with a mixer and thermomechanically (until a maximum temperature of 110 ° C to 190 ° C is reached). A process in which everything is kneaded (for example, in one or more processes) and
-The process of cooling the combined mixture to a temperature below 100 ° C.
-Next, during the second stage (called the "productive" stage), the process of incorporating the cross-linking system and
The process of kneading everything up to a maximum temperature of less than -110 ° C, and
-The process of extruding or calendaring the rubber composition thus obtained, especially in the form of a tire tread.
In this case, the plasticizer containing the mercapto-modified silicone oil is incorporated either during the first stage or during the second stage, or both in the first and second stages.

According to a preferred embodiment of the invention, the first (non-productive) step is carried out in a single thermomechanical step, during which all required components are introduced into a suitable mixer, such as a standard internal mixer. Then, in the second step, for example, after kneading for 1 to 2 minutes, other additives other than the cross-linking system, agents coating any additional filler, or processing aids are introduced. Can be done. The total kneading time in this non-productive stage is preferably 1 to 15 minutes.

After cooling the mixture thus obtained, the cross-linking system can be incorporated at low temperatures (eg, 40 ° C. to 100 ° C.), typically in an external mixer such as an open mill, and then the combined mixture is prepared. , Mix for a few minutes, eg 2-15 minutes (second (productive) step).

According to a particular embodiment of the invention, in combination with the above embodiments described herein, the plasticizer containing the mercapto-modified silicone oil may be added to or instead of the first step during the second step. It can be partially or wholly incorporated. In this regard, the mercapto-modified silicone oil is the remaining plasticizer that can be contained alone or in the essential plasticizers of the invention (eg, at least one liquid plasticizer other than the mercapto-modified silicone oil, at least one carbide). It can be incorporated into a mixer in combination with a compound selected from the group consisting of hydrogen resins and mixtures thereof). For example, the mercapto-modified silicone oil can be fully incorporated during the second stage, while the remaining plasticizer can be fully incorporated during the first stage and vice versa. If the mercapto-modified silicone oil and the remaining plasticizer are separately incorporated into the mixer, the mercapto-modified silicone oil may be incorporated in addition to or instead of the first stage, partially or entirely during the second stage. The remaining plasticizer is preferably fully incorporated during the first step.

The cross-linking system is preferably based on sulfur and primary vulcanization accelerators, especially sulfenamide type accelerators. Various known secondary accelerators or vulcanization activators such as zinc oxide, stearic acid, guanidine derivatives (particularly diphenylguanidine), etc. are added to this vulcanization system in the first non-productive stage and / or production. Incorporated between target stages. The sulfur content is preferably 0.5 to 10.0 phr, more preferably 0.5 to 3.0 phr, and the content of the primary accelerator is preferably 0.5 to 5.0 phr.

The 21st aspect of the present invention is the rubber composition according to any one of the 1st to 20th aspects, and the rubber composition does not contain zinc oxide or is less than 2.0 phr, preferably 1. It can be based on a cross-linking system containing less than .5 phr, more preferably less than 1.0 phr, even more preferably less than 0.5 phr, wherein the cross-linking system is less than 0-2.0 phr, preferably 0-1.1. It means that it contains less than 5 phr, more preferably less than 0 to 1.0 phr, and even more preferably 0 to 0.5 phr. In particular, the cross-linking system does not contain zinc oxide.

Sulfur, in particular thiazole-type accelerators and derivatives thereof, thiuram-type accelerators, or any compound that can act as a vulcanization accelerator for an elastomer matrix, eg, a diene elastomer, in the presence of zinc dithiocarbamate. It can be used as an accelerator (primary or secondary). These accelerators are more preferably 2-mercaptobenzothiazyl disulfide (abbreviated as "MBTS"), N-cyclohexyl-2-benzothiazolesulfenamide (abbreviated as "CBS"), N, N-dicyclohexyl-2benzothiazolesulfenamide (“DCBS”), N-tert-butyl-2-benzothiazolesulfenamide (“TBBS”), N-tert-butyl-2benzothiazolesulfenamide (“TBSI”) ”), Zinc dibenzyldithiocarbamate (“ZBEC”), tetrabenzylthium disulfide (“TBZTD”) and mixtures thereof.

The final composition thus obtained is, for example, a rubber contour element that can be calendared, for example in the form of a sheet or plaque, or used directly as a tire tread, for example, especially for laboratory characterization. Extruded in form.

Vulcanization (or curing) is a known method, generally at a temperature of 110 ° C. to 190 ° C. for a sufficient period of time, eg, especially the curing temperature, the vulcanization rate of the vulcanization system adopted and the composition under consideration. It is done in sufficient time, which can vary from 5 to 90 minutes, depending on the theory.

In the case of a composite type tread formed from several rubber compositions having different formulations, the rubber composition according to the present invention can constitute all or only a part of the tread according to the present invention.

A 22nd aspect of the present invention is a tire containing the rubber composition according to any one of the 1st to 21st aspects.

A 23rd aspect of the present invention is a tire in which the rubber composition according to any one of the 1st to 21st aspects is contained in the tread and / or its side wall, preferably the tread.

The tires of the present invention are passenger vehicles, especially including 4x4 (four-wheel drive) vehicles and SUV (sports utility vehicles) vehicles, and especially vans and heavy vehicles (ie buses or heavy road transport vehicles (trucks, tractors, trailers)). Intended to be installed in industrial vehicles selected from.

Also in the present invention, the above rubber compositions are patterned and intended to be in contact with the road during the rotation of the tire, in particular for the useful life of the tire, in a composite or hybrid type tread, with different formulations. It is applicable when forming only a part of what consists of two layers stacked in the radial direction of (referred to as a "cap base" structure). The base portion of the above formulation is then the radial outer layer of the tread intended to contact the ground from the moment the new tire begins to roll, or on the other hand the tread intended to contact the ground at a later stage. Can form a layer inside the radial direction of.

Further, the rubber composition according to the present invention can constitute only all or a part of the side wall of the tire, which may make it possible to reduce the rolling resistance performance of the tire.

The present invention relates to rubber compositions, treads and sidewalls both in the raw state (ie, before curing) and in the cured state (ie, after cross-linking or vulcanization).

The present invention is further illustrated by the following non-limiting examples.

In the test, nine rubber compositions identified as T-0 to T-4 (references and comparative examples) and C-1 to C-4 (examples according to the invention) are compared. These include diene elastomers (non-functionalized SBR or functionalized SBR with SiOR functional groups) reinforced with a blend of silica and carbon black, and plasticizers with / without dimethyl silicone oil and with / without zinc oxide. based on. Table 1 shows the formulations of the nine rubber compositions in which the contents of the various products are represented by phr, and their properties after curing.

With the exception of the vulcanization system, the reinforced filler, its associated coupling agent, plasticizer, elastomer matrix, and various other components are continuously introduced into an internal mixer with an initial vessel temperature of approximately 60 ° C., thus The mixer was about 70% filled (% by volume). Thermal machining (non-productive step) was then performed in one step, which lasted a total of about 3-4 minutes until the maximum "falling" temperature of 165 ° C was reached. The mixture thus obtained is recovered and cooled, then sulfur and sulfenamide type accelerators are incorporated into an external mixer (homo finisher) at 20-30 ° C. and all are put together for an appropriate period of time (eg 5). ~ 12 minutes) mixed (productive stage).

The composition thus obtained is then cut and / or assembled to the desired dimensions, for example as a tire semi-finished product, in particular a tire tread, and then sheeted (for measurement of physical or mechanical properties). It was calendared in the form of a fine sheet of rubber (2-3 mm thick) or in the form of a directly usable contour element.

^{Dynamic properties G *} and tan (δ) _max at 23 ° C. were measured with a viscosity analyzer (Metrabib VA4000) according to standard ASTM D 5992-96. Record the response of a sample of the sulfide composition (cylindrical test piece with a thickness of 4 mm and a cross-sectional area of 400 mm ² ), eg, according to Standard ASTM D 1349-99, at 23 ° C. or depending on the case of different temperatures. Simple alternating sinusoidal shear stresses were applied at a frequency of 10 Hz under defined temperature conditions. Strain amplitude sweeps were performed from 0.1% to 100% (going cycle) and then from 100% to 1% (return cycle). The results of utilization were the complex dynamic shear modulus G ^* and the loss coefficient tan (δ). In the return cycle, _{the maximum observed tan (δ) identified as tan (δ) max} and also the complex dynamic shear modulus G ^* at 23 ° C. and 10% strain were shown.

^{Generally, the value of the complex dynamic shear modulus G *} at 23 ° C. and 10% strain is a representative value of the low strain stiffness of the material, and the larger the low strain stiffness of the rubber composition, the more the rubber composition is used. It is said by those skilled in the art that the road behavior of the including tires is good. Since the value is expressed as the performance of the road behavior, a value larger than the value of the reference composition T-1 set to 100 indicates that the performance is improved.

By a method well known to those skilled in the art, _{the value of tan (δ) max} at 23 ° C. is a representative value of hysteresis of the material and thus is representative of rolling resistance and tan (δ) at 23 ° C. of the rubber composition. ) _{It is recalled that the lower the max} , the lower the rolling resistance of the tire containing the rubber composition. Since the value is expressed as the performance of rolling resistance, a value larger than the value of the reference composition T-1 set to 100 indicates that the performance has been improved.

The results in Table 1 show that the rubber compositions (C-1 to C-4) according to the invention perform better between lower strain stiffness and hysteresis than those of the reference or comparative examples (T-0 to T-4). It demonstrates that it has an unexpectedly improved balance.

In conclusion, the rubber compositions according to the invention allow for an improved balance of performance between road behavior and tire rolling resistance, as represented by low strain stiffness and hysteresis.

Claims (6)

-R is a hydrogen atom or a hydrocarbon group, a first diene elastomer of 10 to 100 phr having at least one SiOR functional group, and optionally a second diene of 0 to 90 phr different from the first diene elastomer. An elastomer matrix containing an elastomer and
-With a reinforced filler containing at least 60 phr of reinforced inorganic filler,
With a plasticizer containing more than -4 phr of mercapto-modified silicone oil,
A rubber composition based on at least
The functional type of the mercapto-modified silicone oil is an α, ω bifunctional type, a rubber composition. The rubber composition according to claim 1 , wherein the first diene elastomer is a styrene-butadiene copolymer. The rubber composition according to claim 1 or 2 , wherein the SiOR functional group is located at the end of the first diene elastomer chain. The rubber composition according to any one of claims 1 to 3 , wherein R of the SiOR functional group is a hydrocarbon group. A tire containing the rubber composition according to any one of claims 1 to 4. The tire according to claim 5 , wherein the rubber composition according to any one of claims 1 to 4 is contained in a tread and / or a side wall thereof.