BR102013023963B1 - COMPOSITE RUBBER COMPOSITION - Google Patents

Abstract

tire with tread comprised of functionalized elastomer and pretreated silica. the invention relates to a tread tire of a rubber composition containing a functionalized elastomer and pre-hydrophobized precipitated silica reinforcement.

Description

COMPOSITE RUBBER COMPOSITION Field of the Invention

[001] The invention relates to a tread tire of a rubber composition containing a functionalized elastomer having functional groups reactive with the precipitated silica and the pre-hydrophobized precipitated silica.

Background of the Invention

[002] Rubber compositions for the components of various articles of manufacture, including tires, conventionally contain at least one diene-based elastomer, in which the rubber composition can be reinforced with a reinforcing load, such as, for example , at least one of carbon black and precipitated silica, namely, an amorphous synthetic silica containing hydroxyl groups on its surface.

[003] It is recognized that the precipitated silica is hydrophilic in nature, which promotes the charge-charge interaction (eg, the interaction between precipitated silica-precipitated particle) within the rubber composition and tends to resist to the charge-polymer interaction (interaction between precipitated silica-diene-based elastomer) within the rubber composition to thereby cause the dispersion of the precipitated silica particles within the rubber composition. Such a phenomenon is well known to those skilled in such a technique.

[004] The hydrophilic precipitated silica is conventionally coupled to the diene-based elastomer (s) in the rubber composition by the use of a silica coupler, or silica coupling agent, having a portion, such as, for example, an alkoxysilane component, reactive with hydroxyl groups (eg silanol groups) on the precipitated silica and another different portion, such as, for example, a sulfur-containing component, which is, or becomes , interactive with the diene-based elastomer (s) in the rubber composition. Such a coupling of precipitated silica to promote the reinforcement of a rubber composition is well known to those skilled in such a technique.

[005] The reduced interaction between charge-charge is promoted by pre-hydrophobization of the hydrophilic precipitated silica, by pre-treatment of the precipitated silica, before its addition to the rubber composition, with at least one among alkylsilane, alkoxysilane and the coupling of silica previously mentioned containing an alkoxysilane, to react with the hydroxyl groups on the precipitated silica. A portion of the hydroxyl groups on the precipitated silica is therefore pre-forced with the alkylsilane groups, which will not be coupled or bound to a diene-based polymer. When the pretreatment also contains a silica coupling agent, the pre-treated precipitated silica can interact directly with the diene-based elastomer (s) through the coupling agent contained on the precipitated silica, without the addition of a silica coupling agent to the rubber composition itself. The use of such pre-treated, or pre-hydrophobized, precipitated silica to promote the best charge-polymer interaction within a rubber composition is well known to those skilled in such a technique.

[006] The improved interaction between charge-polymer can also be promoted by the use of a functionalized diene-based elastomer containing functional groups reactive with the hydroxyl groups on the precipitated silica. In this way, the functional groups on the elastomer can use the hydroxyl groups on the precipitated silica to react with, thereby promoting their coupling to the functionalized elastomer (s) based on diene in the composition. rubber. Therefore, an added silica coupling agent may or may not be used to assist in coupling the precipitated silica to the diene-based elastomer (s) in the rubber composition.

[007] It is readily considered that such pre-treated precipitated silica having been pre-treated with a silica coupling agent can be used to promote the charge-polymer interaction in a rubber composition containing a functionalized diene-based elastomer with functional groups reactive with the hydroxyl groups on the pre-treated precipitated silica.

[008] However, it is also readily considered that a part of the pre-treated precipitated silica hydro-droxyl groups have been pre-forced by reaction with the silica coupling agent and also the hydrophobizing alkylsilane groups. Therefore, the functional groups on the functionalized diene-based elastomer in the rubber composition will compete with the few remaining free hydroxyl groups on the precipitated silica, which is considered to significantly alter or significantly reduce the functionalized polymer's ability to interact effectively with the surface of the rubber. pre-treated silica and effectively reduce the coupling density of the silica in such a rubber composition, which contains both the pre-treated silica and the functionalized diene-based polymers.

[009] Consequently, this invention relates to a rubber composition containing a functionalized elastomer having functional groups intended to react with the hydroxyl groups contained on the precipitated silica reinforcement, to assist in coupling the precipitated silica with the elastomer and to, with this, promote the reinforcement of the elastomer with the precipitated silica, in which its hydroxyl groups available for this purpose have been significantly reduced, or reduced, by pre-hydrophobation (pre-treatment) of the precipitated silica with a silica coupling agent. , which may include an alkylsilane or alkoxysilane, which are considered to be reactive with the hydroxyl groups on the precipitated silica.

[010] Therefore, the invention particularly relates to rubber compositions containing such a functionalized elastomer and precipitated silica reinforcement, which has been pre-hydrophobized prior to addition to the rubber composition.

[011] It is important to appreciate that the precipitated silica is typically of a hydrophilic nature and therefore does not mix efficiently with diene-based elastomers and rubber compositions containing diene elastomers. Such hydrophilic precipitated silica particles generally favor the joint agglomeration by mutual attraction between their particles within the rubber composition, which promotes the charge-to-charge interaction rather than the charge-to-elastomer interaction, which thus gives a inefficient mixing of the hydrophilic precipitated silica with the rubber composition. Such a phenomenon is well known to those with skill in the technique.

[012] Therefore, there is an inherent motivation to hydrophobize (eg, pre-hydrophobize) such hydrophilic precipitated silica to make it more compatible with the elastomer (s) and, therefore, to promote interaction carcass with elastomer and, therefore, the most efficient mixture with diene-based elastomers.

[013] The hydrophilic precipitated silica can be hydrophobized by treatment with various compounds containing alkoxysilane, for example, the silica coupling agents, which react with the hydroxyl groups on the precipitated silica in situ, within such rubber compositions. Alkoxysilane-based compounds that are not silica coupling agents can also be used for this purpose.

[014] Alternatively, the hydrophilic precipitated silica can be hydrophobized by pretreatment with various silica coupling agents based on alkoxysilane, al-coxysilanes that are not silica coupling agents, or their combination, to make the precipitated silica more hydrophobic prior to introduction into such rubber compositions. For example, and not intended to be limited, see U.S. Patent No. 5,698,619.

[015] In one aspect, it was observed that such prehydrophobization of the precipitated silica with a combination of alkoxyorganomercaptosilane and alkylsilane (eg, alkoxysilane), prior to its addition to the uncured rubber composition, dramatically reduced the hardness of low cold deformation resulting from the sulfur-cured rubber composition, in order to reduce its storage module (G ') in deformations below 50 percent, compared to a rubber composition containing the functionalized elastomer in which the precipitated silica is hydrophobized in situ within the rubber composition, instead of being prehydrophobized before addition to the rubber composition.

[016] Consequently, a challenge is presented to undertake an assessment of how to intensify (increase) such low cold hardness property of the rubber composition containing the functionalized elastomer and prehydrophobized silica. Several approaches to achieve this desired increase in low cold deformation hardness, without significant loss of laboratory rolling resistance properties for a tire tread rubber composition, are listed in the following paragraphs: In some cases, the separate technologies of each can be combined to give the best global approach.

[017] A first embodiment is the inclusion of a hydrophilic precipitated silica in such a rubberized composition containing functionalized elastomer, to create double portions of precipitated silica in the rubber composition, namely, a combination of pre-hydrophobic precipitated silica and hydrophilic precipitated silica. (precipitated silica that has not been pre-hydrophobized), in which the functional groups on the functionalized elastomer are first allowed to react with the hydroxyl groups on the hydrophilic precipitated silica and, after that, allowed to react with the remaining hydroxyl groups on said silica hydrophobic precipitate (hydroxyl groups that remain on the precipitated silica after it has been prehydrophobized) (in the absence of silica coupling agent added to the rubber composition).

[018] By this modality, it is believed that a new reinforcement network can be created containing pre-hydrophobized precipitated silica for the rubber composition containing functionalized elastomer, particularly for the benefit of a tire tread of such a composition. rubber. This results from the functionalized elastomer being the only binding mechanism to the added hydrophilic silica, since no coupling agent is present to bind the elastomer to the silica, regardless of the functional group on the elastomer.

[019] Historically, several rubber compositions and tires with their components have been proposed, which contain double precipitated silica in a form of a combination of pre-hydrophobized precipitated silica together with precipitated silica which is hydrophobized in situ within the composition of rubber with an added silica bonding agent. For example, and not intended to be limiting, see U.S. Patent Nos. 4,474,908, 5,780,538, 6,127,468 and 6,573,324 and U.S. Patent Application No. 2005/0009955. However, it is believed that this step-by-step interaction with the hydrophilic and hydrophobic precipitated silicas of the said first modality is a significant departure from such a practice in the past.

[020] A second embodiment of this evaluation is an inclusion of a hydrophilic precipitated silica (precipitated silica that has not been pre-hydrophobized) and a silica coupling agent in such a rubberized composition containing functionalized elastomer, to create double portions of precipitated silica in the rubber composition, namely, a combination of pre-hydrophobized precipitated silica and hydrophilic precipitated silica, in which the functional groups on the functionalized elastomer are first allowed to react with the hydroxyl groups of the pre-hydrophobized silica and, thereafter, allowed to react with the hydroxyl groups on the hydrophilic precipitated silica, wherein the silica coupling agent is allowed to react with the hydroxyl groups contained both on the prehydrophobized precipitated silica and on the hydrophilic precipitated silica added.

[021] By this modality, it is believed that a new reinforcement network can be created containing the combination of silica coupler reacted with pre-hydrophobized and hydrophilic precipitated silica added to the rubber composition containing functionalized elastomer, particularly for the benefit of a tire tread of such a rubber composition.

[022] A third modality of this evaluation is to combine the short fiber reinforcement together with the functionalized elastomers with any of the first and second aforementioned modalities, to promote an improvement of (an increase in) the cold hardness properties of the cold deformation. rubber composition, while substantially maintaining the cured physical properties of the rubber composition, to promote improved rolling resistance (promote reduced rolling resistance) for tires when such rubber compositions are used in tread applications of tires. Historically, short fiber reinforcement has been used in several rubber compositions, including rubber compositions for tire treads. However, this proposed use of such short fibers is believed to be a significant departure from such earlier use of short fibers in a mixture of rubber composition containing functionalized elastomers combined with prehydrophobized silica. Consideration should be given to the addition of precipitated hydrophilic silica to such combined rubber compositions, as described in the first embodiment of this invention. In this way, one could have a rubber composition comprised of functionalized elastomer capable of binding to a combination of prehydrophobized silica (a precipitated silica having been pre-treated before its addition to an internal rubber mixer) and silica hydrophilic (precipitated silica without pretreatment), combined with an addition of short fibers. Such short fibers can be in the form of, for example, individual fibers or strands cut from a plurality of fibers. Such short fibers can be comprised of at least one of natural and synthetic fibers, such as, for example, at least one of nylon, aramid, polyester, rayon, cellulose and cotton.

[023] A fourth embodiment of this invention is to add a resin formed in situ to the rubber of any of the first, second and third embodiments mentioned above, as a product of a combination of methylene donor and methylene receptor. Historically, resin products from a methylene donor and methylene receptor, formed in situ within a rubber composition, have been proposed in several rubber compositions, including rubber compositions for tire treads. However, it is believed that their inclusion in any of the first, second and third modalities mentioned above is a significant departure from such a practice in the past. Examples of methylene donor and methylene receptor systems are discussed in U.S. Patent No. 3,517,722. Representative of methylene donors are, for example, hexamethylenetetramine and hexamethoxymethylmelamine. Representative of methylene receptors, for example, resorcinol, resorcinol monobenzoate, phenolic cashew nut oil resin, polyhydric phenoxy resin and reactive phenol / formaldehyde resin.

• (A) combinação de sílica precipitada hidrofílica e pré-hidrofobizada sequencialmente adicionada
• (B) combinação de sílica precipitada hidrofílica e pré-hidrofobizada sequencialmente adicionada, juntamente com um agente de acoplamento de sílica,
• (C) reforço de fibra curta em uma forma de dispersão de fibras curtas distintas, com ou sem sílica precipitada hidrofílica adicionada e com ou sem agente de acoplamento de sílica adicionado, e
• (D) produto de resina de um doador de metileno e receptor de metileno formado in situ na composição de borracha, com ou sem sílica precipitada hidrofílica adicionada e com ou sem agente de acoplamento de sílica adicionado e com ou sem fibras curtas distingas.

[024] It is, therefore, a special challenge to evaluate the inclusion of at least one, or a combination, of the following materials, as described in the different modalities, in a rubber composition containing a functionalized diene-based elastomer and pre-silica. hydrophobized, to determine its impact on the low hardness of cold deformation, desirably to promote its increase, and also its elasticity property, which would desirably be maintained, or the improved rolling resistance performance (the reduction in the performance of rolling resistance) in tires when such rubber compositions are used in tire treads, in particular.

• (A) combination of precipitated hydrophilic and prehydrophobized silica sequentially added
• (B) combination of hydrophilic precipitated silica and prehydrophobized sequentially added, together with a silica coupling agent,
• (C) short fiber reinforcement in a distinct short fiber dispersion form, with or without added hydrophilic precipitated silica and with or without added silica coupling agent, and
• (D) resin product from a methylene donor and methylene receptor formed in situ in the rubber composition, with or without added hydrophilic precipitated silica and with or without added silica coupling agent and with or without distinguished short fibers.

[025] In the description of this invention, the term "phr" refers to parts by weight for a material or ingredient per 100 parts by weight of elastomer (s). The terms "rubber" and "elastomer" may be used interchangeably, unless otherwise specified. The terms "cure" and "vulcanize" can be used interchangeably, unless otherwise stated.

Summary and Practice of the Invention

• (1) pelo menos um elastômero à base de dieno funcionalizado, ou
• (2) uma combinação de pelo menos um elastômero à base de dieno funcionalizado e pelo menos um elastômero à base de dieno não funcionalizado, em que a dita combinação contém mais do que 50 por cento (em peso) do(s) dito(s) elastômero(s) à base de dieno funcionalizado(s), e

(B) cerca de 30 a cerca de 120 phr de carga de reforço composta de:

• (1) sílica precipitada, ou
• (2) uma combinação de sílica precipitada e negro de fumo de reforço de borracha contendo até cerca de 65 phr de negro de fumo de reforço de borracha;

em que a dita sílica precipitada é composta de:

• (a) sílica precipitada pré-hidrofobizada (sílica precipitada hidrofobizada antes de sua adição à composição de borracha) e, opcionalmente, um agente de acoplamento de sílica adicionado à dita composição de borracha, ou
• (b) uma combinação de sílica precipitada pré-hidrofobizada e sílica precipitada hidrofílica e, opcionalmente, um agente de acoplamento de sílica adicionado à dita composição de borracha,

em que a dita sílica precipitada pré-hidrofobizada é hidrofobizada antes de sua adição à composição de borracha por tratamento com:

• (i) pelo menos um dentre um alquilsilano e alcoxissilano, particularmente um al-coxissilano, ou
• (ii) uma combinação de pelo menos um dentre um alquilsilano e alcoxissilano (particularmente um alcoxissilano) juntamente com pelo menos um dentre um polissulfeto de organoalcoxissilila e organomercaptoalcoxissilano, ou
• (iii) pelo menos um dentre um polissulfeto de organoalcoxissilila e organomercaptoalcoxissilano,

em que a dita sílica precipitada hidrofílica é opcionalmente hidrofobizada in situ dentro da composição de borracha e é hidrofobizada por tratamento dentro da composição de borracha com:
(iv) pelo menos um dentre um alquilsilano e alcoxissilano, particularmente um al-coxissilano, ou
(v) uma combinação de pelo menos um dentre um alquilsilano e alcoxissilano (particularmente um alcoxissilano) juntamente com um alcoxissilano e pelo menos um dentre um polissulfeto de organoalcoxissilila e organomercaptoalcoxissilano, ou
(vi) pelo menos um dentre um polissulfeto de organoalcoxissilila e organomercap-toalcoxissilano, e
em que o dito elastômero à base de dieno adicional é composto de pelo menos um polímero de pelo menos um dentre isopreno e 1,3-butadieno e copolímeros de estireno e pelo menos um dentre isopreno e 1,3-butadieno; e
em que o dito elastômero funcionalizado é composto de pelo menos um dentre elastômero de cis 1,4-poli-isopreno funcionalizado (IR funcionalizado), elastômero de cis 1,4-polibutadieno funcionalizado (BR funcionalizado), elastômero de copolímero de estire-no/butadieno funcionalizado (SBR funcionalizado), elastômero de copolímero de isopre-no/butadieno funcionalizado (IBR funcionalizado) e estireno/isopreno/butadieno funcionali-zado (SIBR funcionalizado) e elastômeros preparados em solução de solvente orgânico acoplados com estanho de pelo menos um dentre isopreno e 1,3-butadieno e estireno, com pelo menos um dentre isopreno e 1,3-butadieno, em que os grupos funcionais dos ditos elastômeros são reativos com os grupos hidroxila da sílica precipitada.[026] According to this invention, a rubber composition is composed of, based on parts by weight per 100 parts by weight of rubber (phr):
(A) 100 phr of at least one diene-based elastomer composed of:

• (1) at least one functionalized diene-based elastomer, or
• (2) a combination of at least one functionalized diene-based elastomer and at least one non-functionalized diene-based elastomer, wherein said combination contains more than 50 percent (by weight) of said ) functionalized diene-based elastomer (s), and

(B) about 30 to about 120 phr of reinforcement charge composed of:

• (1) precipitated silica, or
• (2) a combination of precipitated silica and rubber reinforced carbon black containing up to about 65 phr of rubber reinforced carbon black;

wherein said precipitated silica is composed of:

• (a) prehydrophobized precipitated silica (hydrophobic precipitated silica prior to its addition to the rubber composition) and, optionally, a silica coupling agent added to said rubber composition, or
• (b) a combination of pre-hydrophobized precipitated silica and hydrophilic precipitated silica and, optionally, a silica coupling agent added to said rubber composition,

wherein said pre-hydrophobized precipitated silica is hydrophobized prior to its addition to the rubber composition by treatment with:

• (i) at least one of an alkylsilane and alkoxysilane, particularly an al-coxysilane, or
• (ii) a combination of at least one of an alkylsilane and alkoxysilane (particularly an alkoxysilane) together with at least one of an organoalkoxysilyl and organomercaptoalkoxysilane polysulfide, or
• (iii) at least one of an organoalkoxysilyl and organomercaptoalkoxysilane polysulfide,

wherein said hydrophilic precipitated silica is optionally hydrophobized in situ within the rubber composition and is hydrophobized by treatment within the rubber composition with:
(iv) at least one of an alkylsilane and alkoxysilane, particularly an al-coxysilane, or
(v) a combination of at least one of an alkylsilane and alkoxysilane (particularly an alkoxysilane) together with an alkoxysilane and at least one of an organoalkoxysilyl and organomercaptoalcoxysilane polysulfide, or
(vi) at least one of an organoalkoxysilyl and organomercap-toalcoxysilane polysulfide, and
wherein said additional diene-based elastomer is composed of at least one polymer of at least one of isoprene and 1,3-butadiene and styrene copolymers and at least one of isoprene and 1,3-butadiene; and
wherein said functionalized elastomer is composed of at least one of the functionalized 1,4-polyisoprene cis elastomer (functionalized IR), functionalized 1,4-polybutadiene cis elastomer (functionalized BR), stretch-copolymer elastomer / functionalized butadiene (functionalized SBR), isopre-copolymer elastomer / functionalized butadiene (functionalized IBR) and functionalized styrene / isoprene / butadiene (functionalized SIBR) and elastomers prepared in solution of organic solvent coupled with tin of at least one between isoprene and 1,3-butadiene and styrene, with at least one among isoprene and 1,3-butadiene, in which the functional groups of said elastomers are reactive with the hydroxyl groups of the precipitated silica.

• (A) reforço de fibra curta, e
• (B) produto de resina de doador de metileno e receptor de metileno.

[027] In one embodiment, said rubber composition additionally contains at least one additive composed of at least one of:

• (A) short fiber reinforcement, and
• (B) methylene donor and methylene receptor resin product.

• (A) o grupo funcional amina reativo com os grupos hidroxila na dita sílica precipitada, ou
• (B) o grupo funcional silóxi, incluindo os grupos silóxi da cadeia de extremidade, reativo com os grupos hidroxila na dita sílica precipitada, ou
• (C) uma combinação de grupos funcionais amina e silóxi reativos com os grupos hidroxila na dita sílica precipitada, ou
• (D) uma combinação de grupos funcionais tiol e silóxi reativos com os grupos hi-droxila na dita sílica precipitada, ou
• (E) uma combinação de grupos funcionais imina e silóxi reativos com os grupos hidroxila na dita sílica precipitada, ou
• (F) grupos funcionais hidroxila reativos com a dita sílica precipitada, ou
• (G) grupos epóxi reativos com os grupos hidroxila na dita sílica precipitada, ou
• (H) grupos carboxila reativos com os grupos hidroxila na dita sílica precipitada.

[028] Representative examples of said non-functionalized diene elastomers are, for example, and not intended to be limiting, cis 1,4-polyisoprene (particularly natural and synthetic rubber), 1, 4-polybutadiene (particularly cis 1,4-polybutadiene) and

• (A) the amine functional group reactive with the hydroxyl groups on said precipitated silica, or
• (B) the siloxy functional group, including the end chain siloxy groups, reactive with the hydroxyl groups on said precipitated silica, or
• (C) a combination of amine and siloxy functional groups reactive with the hydroxyl groups in said precipitated silica, or
• (D) a combination of thiol and siloxy functional groups reactive with the hydroxyl groups in said precipitated silica, or
• (E) a combination of functional groups imine and siloxy reactive with the hydroxyl groups in said precipitated silica, or
• (F) hydroxyl functional groups reactive with said precipitated silica, or
• (G) epoxy groups reactive with hydroxyl groups on said precipitated silica, or
• (H) carboxyl groups reactive with hydroxyl groups on said precipitated silica.

[029] In one embodiment, said functionalized elastomer contains functional group (s) composed of:

[030] For functionalized elastomers, representative of functionalized SBR elastomers are, for example, the functionalized SBR elastomers within the chain mentioned in U.S. Patent No. 6,936,669.

[031] It is representative of a combination of amino-siloxy-functionalized SBR elastomers with one or more amino-siloxy groups attached to the elastomer, for example, JSR's HPR355 ™ and the functionalized SBR elastomers mentioned in the Publication US Patent Application No. 2007/0185267.

[032] Representative styrene / butadiene elastomers functionalized at the end with a silane-sulfide group are, for example, mentioned in patent publication WO 2007/047943.

[033] It is representative of hydroxy functionalized SBR elastomers, for example, Asahi Tufdene 3330 ™.

[034] It is representative of epoxy-functionalized SBR elastomers, for example, Asahi's Tufdene E50 ™.

• (A) combinar uma sílica precipitada pré-hidrofobizada com uma composição de borracha contendo pelo menos um elastômero à base de dieno conjugado incluindo o dito elastômero funcionalizado, em pelo menos uma etapa de mistura não produtiva preparatória, em um misturador de borracha interno (em uma temperatura de, por exemplo, em uma faixa de, cerca de 135°C a cerca de 175°C);
• (B) remover a dita composição de borracha contendo sílica precipitada pré-hidrofobizada de seu misturador de borracha interno (e permitir que a dita composição de borracha, após isso, esfrie até uma temperatura abaixo de cerca de 40°C);
• (C) combinar uma sílica precipitada hidrofílica com a dita composição de borracha contendo sílica precipitada pré-hidrofobizada na mesma etapa de mistura ou em pelo menos uma etapa de mistura não produtiva preparatória diferente e subsequente (subsequente à dita etapa de mistura não produtiva preparatória na qual a dita sílica precipitada pré-hidrofobizada é adicionada) em um misturador de borracha interno (na ausência da adição de um agente de hidrofobização contendo silano para a dita sílica precipitada hidrofílica), para formar uma composição de borracha que contém porções de sílica duplas em uma forma de uma combinação da dita sílica precipitada pré-hidrofobizada e a dita sílica precipitada hidrofílica,

em que a dita sílica pré-hidrofobizada é hidrofobizada antes de sua adição à dita composição de borracha com pelo menos um agente de hidrofobização composto de um alcoxissilano, polissulfeto de organossiloxissilila e organomercaptoalcoxissilano.[035] For example, a method of preparing a precipitated silica-reinforced rubber composition for a tire tread is provided, which is composed of at least two preparatory non-productive mixing steps, followed by a productive mixture, which comprises, based on parts by weight per 100 parts by weight of rubber (phr):

• (A) combining a pre-hydrophobized precipitated silica with a rubber composition containing at least one conjugated diene-based elastomer including said functionalized elastomer, in at least one preparatory non-productive mixing step, in an internal rubber mixer (in a temperature of, for example, in the range of about 135 ° C to about 175 ° C);
• (B) removing said rubber composition containing pre-hydrophobized precipitated silica from its internal rubber mixer (and allowing said rubber composition thereafter to cool to a temperature below about 40 ° C);
• (C) combining a hydrophilic precipitated silica with said rubber composition containing prehydrophobized precipitated silica in the same mixing step or in at least one different and subsequent preparatory non-productive mixing step (subsequent to said preparatory non-productive mixing step in to which said prehydrophobized precipitated silica is added) in an internal rubber mixer (in the absence of the addition of a silane-containing hydrophobizing agent to said hydrophilic precipitated silica), to form a rubber composition containing double portions of silica in a form of a combination of said pre-hydrophobic precipitated silica and said hydrophilic precipitated silica,

wherein said prehydrophobized silica is hydrophobized prior to its addition to said rubber composition with at least one hydrophobizing agent composed of an alkoxysilane, organosiloxysilyl polysulfide and organomercaptoalcoxysilane.

• (A) combinar uma sílica precipitada pré-hidrofobizada com uma composição de borracha contendo pelo menos um elastômero à base de dieno conjugado incluindo o dito elastômero funcionalizado, em pelo menos uma etapa de mistura não produtiva preparatória, em um misturador de borracha interno (em uma temperatura de, por exemplo, em uma faixa de, cerca de 135°C a cerca de 175°C);
• (B) combinar uma sílica precipitada hidrofílica com a dita composição de borracha contendo sílica precipitada pré-hidrofobizada em uma etapa de mistura não produtiva igual ou diferente (antes ou após a adição da dita sílica precipitada pré-hidrofobizada) em um misturador de borracha interno (na ausência da adição de um agente de hidrofobização contendo silano para a dita sílica precipitada adicional hidrofílica), para formar uma composição de borracha que contém porções de sílica duplas em uma forma de uma combinação da dita sílica precipitada pré-hidrofobizada e a dita sílica precipitada hidrofílica,

em que a dita sílica pré-hidrofobizada é hidrofobizada antes de sua adição à dita composição de borracha com pelo menos um agente de hidrofobização composto de um alcoxissilano, alcoxissilano, polissulfeto de organossiloxissilila e organomercaptoalcoxissila-no.[036] For example, there is provided a method of preparing a precipitated silica-reinforced rubber composition for a tire tread, comprising at least one preparatory non-productive mixing step, followed by a productive mixing step, comprising, based on parts by weight per 100 parts by weight of rubber (phr):

• (A) combining a pre-hydrophobized precipitated silica with a rubber composition containing at least one conjugated diene-based elastomer including said functionalized elastomer, in at least one preparatory non-productive mixing step, in an internal rubber mixer (in a temperature of, for example, in the range of about 135 ° C to about 175 ° C);
• (B) combining a hydrophilic precipitated silica with said rubber composition containing pre-hydrophobized precipitated silica in an equal or different non-productive mixing step (before or after the addition of said pre-hydrophobized precipitated silica) in an internal rubber mixer (in the absence of the addition of a silane-containing hydrophobizing agent to said additional hydrophilic precipitated silica), to form a rubber composition containing double portions of silica in a form of a combination of said pre-hydrophobized precipitated silica and said silica hydrophilic precipitate,

wherein said prehydrophobized silica is hydrophobized prior to its addition to said rubber composition with at least one hydrophobizing agent composed of an alkoxysilane, alkoxysilane, organosiloxysilyl polysulfide and organomercaptoalcoxysiline.

• (A) na mesma etapa de mistura não produtiva, antes ou após a adição da sílica precipitada pré-hidrofobizada, ou
• (B) em uma etapa de mistura não produtiva separada, depois da adição da sílica precipitada pré-hidrofobizada, ou
• (C) em uma etapa de mistura não produtiva separada, depois da adição da sílica precipitada pré-hidrofobizada, com uma etapa de mistura não produtiva separada adicional entre elas, ou
• (D) em uma etapa de mistura produtiva subsequente, separada, na qual o enxofre e os agentes de cura de enxofre são adicionados à composição de borracha.

[037] In practice, the mixture of the precipitated hydrophilic silica with at least one diene-based elasomer including said functionalized elastomer can be administered, for example:

• (A) in the same non-productive mixing step, before or after the addition of the pre-hydrophobized precipitated silica, or
• (B) in a separate non-productive mixing step, after the addition of the pre-hydrophobized precipitated silica, or
• (C) in a separate non-productive mixing step, after the addition of the pre-hydrophobized precipitated silica, with an additional separate non-productive mixing step between them, or
• (D) in a subsequent, separate productive mixing step, in which sulfur and sulfur curing agents are added to the rubber composition.

[038] In practice, as indicated above, said hydrophobizing agent to hydrophobize said hydrophilic precipitated silica, for the purposes of this invention, is at least one among alkylsilane, alkoxysilane, organosiloxysilyl polysulfide and organomercaptoalkoxysilane, alternatively with a combination of alkoxysilane and at least one of said organosiloxysilyl or organomercaptoalkoxysilane polysulfide.

[039] In practice, it is representative of said organoalkoxysilyl polysulfides, for example, a bis (3-trialkoxysilylpropyl) polysulfide having an average of about 2 to about 4, optionally an average in a range of about 2 to about of 2.6, or in a range of about 3.2 to about 3.8, sulfur atoms in their polysulfidic bridge. Examples of said bis (3-trialkoxysilylalkyl) polysulfide are composed of a bis (3-triethoxysilylpropyl) polysulfide.

[040] In practice, it is representative of said alkoxysilane, for example, an alkoxysilane of the general formula (I):
(I) Zn - Si - R4-n
where R is a saturated alkyl radical having from one to 18, preferably from one to 8, carbon atoms, such as, for example, the methyl, ethyl, isopropyl, n-butyl and octadecyl radicals, n is a value of 1 to 3 and Z is an alkoxy radical represented as (R1O) -, where R1 is a saturated alkyl radical having one to 3 carbon atoms, such as, for example, the methyl, ethyl and isopropyl radicals, preferably at least one among methyl and ethyl radicals.

[041] Representative examples of alkoxysilanes of Formula (I) are, for example, trimethoxy methyl silane, dimethoxy dimethyl silane, methoxy trimethyl silane, trimethoxy propyl silane, trimethoxy octyl silane, trimethoxy hexadecyl silane, dimethoxy dipropyl silane, triethoxy triethoxy propyl silane, triethoxy octyl silane, and diethoxy dimethyl silane.

[042] Consequently, said alkoxysilanes have an alkoxy group being reactive with the hydroxyl groups (eg, silane groups) contained on the surface of the precipitated silica aggregates.

[043] In the practice of this invention, the rubber composition can be comprised of several conjugated diene-based elastomers, in addition to said functionalized elastomer. Such additional diene-based elastomers can be, for example, at least one of the polymers composed of at least one of isoprene and 1,3-butadiene, and styrene copolymers and at least one conjugated diene hydrocarbon composed of isoprene and 1, 3-butadiene, as well as elastomers prepared by polymerization in organic solution coupled with tin.

[044] For example, representative of such additional elastomers are natural 1,4-polyisoprene cis rubber, synthetic 1,4-polyisoprene rubber, 1,4-polybutadiene cis rubber, polybutadiene rubber with a high vinyl content having a 1.2 vinyl content in a range of about 10 percent to about 90 percent, styrene / butadiene copolymer rubber (SBR) (copolymers prepared by emulsion polymerization aqueous solution or organic solution) and including SBR prepared by polymerization in organic solvent having a content of 1.2 vinyl in a range of about 10 to about 90 percent, based on its part derived from polybutadiene, and a content of polystyrene in a range of about 10 to about 60 percent, based on the copolymer, styrene / high copolymer 1,4-butadiene copolymer rubber having a trans-1,4 content in the range of about 40 to about 80 percent, based on its part derived from polybutadiene, terpolymer rubber styrene / isoprene / butadiene rubber, butadiene / acrylonitrile rubber, styrene / isoprene copolymer rubber and isopre-no / butadiene copolymer, 3,4-polyisoprene rubber and trans rubber 1,4-polybutadiene.

[045] Additional representative examples of such additional elastomers are, for example, tin or silicon coupled elastomers prepared by polymerization in organic solution, such as, for example, styrene / butadiene copolymers coupled with tin or silicon can also be used.

[046] Copolymers coupled with styrene tin / butadiene can be prepared, for example, by introducing a tin coupling agent during the copolymerization reaction of styrene monomer / 1,3-butadiene in a solution of organic solvent , usually at, or close to, the end of the polymerization reaction. Such coupling of styrene / butadiene copolymers is well known to those skilled in such a technique.

[047] For such coupled elastomers, it is normally desired that at least 50 percent, and more generally, in a range of about 60 to about 85 percent, of the Sn (tin) bonds in the tin-coupled elastomers are attached to the butadiene units of the styrene / butadiene copolymer to create Sn-dienyl bonds, such as butadienyl bonds.

[048] The creation of tin-dienyl bonds can be carried out in several ways, such as, for example, the sequential addition of butadiene to the copolymerization system or the use of modifiers to change the reactivity ratios of styrene and / or butadiene for copolymerization. It is believed that such practices, whether used with a batch copolymerization system, or with a continuum, are well known to those skilled in such a technique.

[049] Several tin compounds, particularly organo-tin compounds, can be used for coupling the elastomer. Representative of such compounds are, for example, alkyl tin trichloride, dialkyl tin dichloride, which produce variants of a styrene / butadiene copolymer elastomer coupled with tin, although a trialkyl tin monochloride could be used, which would produce simply a tin-terminated copolymer.

[050] Examples of elastomers modified, or coupled, with tin are, for example, the elastomers of styrene / butadiene copolymers exemplified, for example, in U.S. Patent No. 5,064,901.

[051] Several commercially available synthetic amorphous precipitated silicas (precipitated silicas) can be used for the precipitated silicas for this invention. Such silicas can be characterized, for example, by their BET and CTAB surface areas. Representative of such silicas, for example, only and without limitation, the silicas of PPG Industries under the trademark Hi-Sil, with the designations 210, 243, etc .; the silicas of Rhodia, with the designations of Zeosil 1165MP and Zeosil 165GR, the silicas of Evo-nic, with the designations VN2 and VN3, and the silicas of Huber, such as Zeopol 8745 and Zeopol 8715.

[052] It is readily understood by those skilled in the art that the rubber composition would be combined by the methods generally known in the technique of combining rubbers, such as mixing the various vulcanizable constituent rubbers with sulfur with the various commonly used additive materials , such as, for example, curing aids, such as sulfur, activators, retarders and accelerators, processing additives such as oils, resins, including tackiness resins and plasticizers, fillers , pigments, fatty acid, zinc oxide, waxes, antioxidants and anti-zonizers, peptizing agents and reinforcing materials.

[053] The presence and relative quantities of the aforementioned additives are not considered to be an aspect of the present invention, unless otherwise stated, which is more primarily directed at a tire with a tread, including the tread surface of the tread. of a rubber composition containing double portions of silica in a form of a pre-hydrophobized precipitated silica and a hydrophilic precipitated silica in combination with a functionalized elastomer containing functionalities reactive with the hydroxyl groups (eg silanol groups) on the precipitated silica.

[054] Tires can be produced, shaped, molded and cured by various methods, which will be readily apparent to those having skill in such a technique.

[055] The following Example is provided to further understand the invention. Parts and percentages are by weight, unless otherwise stated.

EXAMPLE I (Control and Comparative Rubber Sample)

[056] Experiments were conducted to evaluate the effect of using a combination of hydrophilic precipitated silica, hydrophobized in situ in an internal rubber mixer (eg, Banbury mixer), using an added silica coupling agent , compared to a prehydrophobized precipitated silica without added hydrophilic silica or addition of a silica coupling agent within a rubber composition rubber containing a functionalized elastomer. This example will address the issues of this approach with regard to obtaining a rubber composition for tread component applications in a tire, in which dramatic improvement (reduction) in rolling resistance can be obtained, with a corresponding reduction in the low property. cold deformation hardness, which could negatively impact the wet and dry handling performance of the tire.

[057] It is understood that the functional groups of the functionalized elastomer are reactive with the hydroxyl groups available on the precipitated silicas.

[058] Rubber composition A (control rubber sample) represents the addition of hydrophilic precipitated silica, in the presence of silica coupling agent, to a rubber composition containing a functionalized SBR polymer (styrene / butadiene rubber) and a non-functionalized PBD polymer (1,4-polybutadiene cis rubber). Sample B (comparative rubber sample) represents the use of pre-hydrophobized precipitated silica added to the same combination of polymers, in the absence of any added silica coupling agent.

[059] The rubber compositions, Rubber sample A and Rubber sample B, were prepared by mixing the elastomers with the precipitated silica fillers and the silica coupling agent, when added, in at least one non-productive mixing step. initial, followed by a non-productive sequential mixing (NP) stage, in an internal rubber mixer (Banbury rubber mixer), for about 4 minutes, up to a temperature of about 160 ° C. The rubber compositions were subsequently mixed in a productive mixing stage (P), in an internal rubber mixer (Banbury mixer), with a sulfur curing package, namely, sulfur and sulfur curing accelerator (s), for about 2 minutes, until a drop temperature of, for example, about 115 ° C. The rubber compositions were removed from the internal mixer after each mixing step and cooled to below 40 ° C between each individual non-productive mixing stage and before the final productive mixing stage.

Estágio de Mistura Produtivo (P)

• 1 Um elastômero de estireno/butadieno preparado por polimerização em solução acoplado com estanho, contendo um grupo funcional siloxila (silóxi) na cadeia terminal, reativo com os grupos hidroxila de uma sílica precipitada
• 2 Borracha de cis 1,4-poli-isopreno natural (TRS20)
• 3 Sílica precipitada pré-hidrofobizada (pré-tratada) com uma combinação de mercap-toalcoxissilano e alquilsilano (p.ex., alcoxissilano) como Agilon 400™ da PPG Industries
• 4 Sílica precipitada hidrofílica (não pré-hidrofobizada) como Zeosil 1165MP™ da Rhodia
• 5 Agente de acoplamento como um polissulfeto de bis(3-trietoxissililpropila) tendo uma média de cerca de 2 a cerca de 2,6 átomos de enxofre de ligação em sua ponte polis-sulfídica como Si-266™ da Evonic
• 6 Antidegradantes à base de amina
• 7Negro de fumo de reforço da borracha N299, uma designação da ASTM 8Principalmente composto de ácidos esteárico, palmítico e oléico 9Aceleradores de cura de enxofre de sulfenamida e guanidina

[060] The basic formulation for Control Rubber Sample A and Comparative Rubber Sample B is shown in Table 1 below, expressed in parts by weight per 100 parts of rubber (phr), unless otherwise stated.

Productive Mixing Stage (P)

• 1 A styrene / butadiene elastomer prepared by polymerization in solution coupled with tin, containing a siloxyl functional group (siloxide) in the terminal chain, reactive with the hydroxyl groups of a precipitated silica
• 2 Natural 1,4-polyisoprene cis rubber (TRS20)
• 3 Pre-hydrophobized (pre-treated) precipitated silica with a combination of mercap-toalcoxysilane and alkylsilane (eg, alkoxysilane) such as Agilon 400 ™ from PPG Industries
• 4 Hydrophilic precipitated silica (not pre-hydrophobized) like Zeosil 1165MP ™ from Rhodia
• 5 Coupling agent such as bis (3-triethoxysilylpropyl) polysulfide having an average of about 2 to about 2.6 sulfur atoms bonding on its polysulfide bridge like Evonic's Si-266 ™
• 6 Amine-based anti-degraders
• 7N299 rubber reinforcing carbon black, an ASTM designation 8Mainly composed of stearic, palmitic and oleic acids 9Sulfenamide and guanidine sulfur curing accelerators

Propriedades
Propriedades de Manuseio Preditivas da Banda de Rodagem de Pneu, Módulo de armazenagem curado (G’)1 a 100°C, 11 Hertz (RPA)1

Propriedades Preditivas de Resistência ao Rolamento da Banda de Rodagem de Pneu
(Os valores maiores para a elasticidade e os valores menores para a Tan Delta são preditivos da redução benéfica na resistência ao rolamento do pneu)

Propriedades de Desempenho a Úmido Preditivas da Banda de Rodagem de Pneu

Propriedade Preditiva do Desgaste da Banda de Rodagem de Pneu, Resistência à Abrasão
(Taxa de abrasão, Menor é melhor)

Resistência ao Rasgo3, (adesão de peal) N

• 1 Dados de acordo com o Analisador de Processo de Borracha (RPA)
• 2 Raspador LAT-100 da taxa de abrasão de Grosch, medida em termos de mg/km de borracha friccionada. A amostra de borracha de teste é colocada em um ângulo de inclinação, sob carga constante (Newtons), à medida que percorre uma dada distância sobre um disco abrasivo rotativo (p.ex., disco da HB Schleifmittel GmbH). Na prática, um teste de gravidade da abrasão Baixa pode ser corrido, por exemplo, em uma carga de 20 Newtons, ângulo de inclinação de 2°, velocidade do disco de 40 km/h para uma distância de 7.500 metros; um teste de gravidade da abrasão Média pode ser corrido, por exemplo, em uma carga de 40 Newtons, ângulo de inclinação de 6°, velocidade do disco de 20 km/h e distância de 1.000 metros; um teste de gravidade da abrasão Alta pode ser corrido, por exemplo, em uma carga de 70 Newtons, ângulo de inclinação de 12°, velocidade do disco de 20 km/h e distância de 250 metros; e um teste de gravidade da abrasão Ultra-alta pode ser corrido, por exemplo, em uma carga de 70 Newtons, ângulo de inclinação de 16°, velocidade do disco de 20 km/h e distância de 500 metros.
• 3 Dados obtidos de acordo com um teste de resistência ao rasgo (adesão de peal) para determinar a adesão interfacial entre duas amostras de uma composição de borracha. Em particular, tal adesão interfacial é determinada removendo uma composição de borracha da outra, em um ângulo reto com a amostra de teste não rasgada, com as duas extremidades das composições de borracha sendo separadas, em um ângulo de 180° uma com a outra, usando um instrumento Instron, a 95°C, e descrita como força em Newtons.

[061] Table 2 below illustrates the curing behavior and the various physical properties of rubber compositions based on the basic formula in Table 1 and described in this document as a Control Rubber Sample A and Comparative Rubber Sample B. Where the cured rubber samples are examined, as for tension-deformation, elasticity and hot hardness values, the rubber samples were cured for about 12 minutes, at a temperature of about 170 ° C.

properties
Predictive Handling Properties of Tire Tread, Cured Storage Module (G ') 1 at 100 ° C, 11 Hertz (RPA) 1

Predictive Properties of Tire Tread Resistance
(Higher values for elasticity and lower values for Tan Delta are predictive of the beneficial reduction in tire rolling resistance)

Predictive Wet Performance Properties of Tire Tread

Predictive Property of Tire Tread Wear, Abrasion Resistance
(Abrasion rate, lower is better)

Tear resistance3, (skin adhesion) N

• 1 Data according to the Rubber Process Analyzer (RPA)
• 2 LAT-100 scraper of the Grosch abrasion rate, measured in terms of mg / km of rubbed rubber. The test rubber sample is placed at an angle of inclination, under constant load (Newtons), as it travels a given distance over a rotating abrasive wheel (eg wheel from HB Schleifmittel GmbH). In practice, a Low abrasion gravity test can be run, for example, on a load of 20 Newtons, inclination angle of 2 °, disc speed of 40 km / h for a distance of 7,500 meters; a Medium abrasion gravity test can be run, for example, on a load of 40 Newtons, inclination angle of 6 °, disk speed of 20 km / h and distance of 1,000 meters; a high abrasion gravity test can be run, for example, on a load of 70 Newtons, inclination angle of 12 °, disk speed of 20 km / h and distance of 250 meters; and an Ultra-high abrasion gravity test can be run, for example, on a load of 70 Newtons, inclination angle of 16 °, disk speed of 20 km / h and distance of 500 meters.
• 3 Data obtained according to a tear resistance test (peal adhesion) to determine the interfacial adhesion between two samples of a rubber composition. In particular, such interfacial adhesion is determined by removing one rubber composition from the other, at a right angle to the unteared test sample, with the two ends of the rubber compositions being separated, at an angle of 180 ° to each other, using an Instron instrument, at 95 ° C, and described as force in Newtons.

[062] It can be seen in Table 2 that Comparative Sample B, which contains pre-hydrophobized silica in the presence of a functionalized SBR elastomer, provides a dramatic improvement in elasticity and tan delta that would predict a significant improvement in rolling resistance. of the tire, when such a compound is used in a tire tread component.

[063] In contrast, the same Comparative Sample B, which contains prehydrophobized silica and functionalized SBR, shows a dramatic reduction in the cold hardness properties of 1 and 10 percent deformation, which would predict a significant loss of wet and dry handling performance. The challenge, therefore, is to maintain the predictive improvement in rolling resistance, while improving the performance of the compounds, predictive of good wet and dry handling. The following examples will show the approaches to the materials that were attempted to achieve this goal.

EXAMPLE II

[064] Experiments were conducted to evaluate the effect of adding hydrophilic precipitated silica, not pretreated, to the prehydrophobized precipitated silica (pretreated), in the internal rubber mixer (Banbury mixer), without the addition of silica coupling to the compounds (Samples of rubber composition). The Control C rubber sample contained 84 phr of the pretreated silica, while the Rubber Samples D, E and F contained, in addition to the 84 phr of the pretreated silica, 5, 10 and 15 phr, respectively, of the precipitated silica. not pre-treated, therefore, hydrophilic.

[065] This example represents an attempt to increase the low cold deformation hardness of the compound containing the pre-treated (pre-hydrophobized) precipitated silica by adding several levels of untreated (therefore, hydrophilic) precipitated silica without the addition of silica coupling agent. The success of this approach and others listed in the examples that follow demonstrates an ability to increase the low hardness of cold deformation, without a significant penalty for hysteresis, for the rubber composition for which less hysteresis of the composition is desired. rubber, to promote an improvement in the (lower) rolling resistance of the tire to the tire with a tread of such a rubber composition.

[066] The basis of the rubber composition (rubber compound) is illustrated in Table 3 below, where parts and percentages are described in terms of parts by weight, unless otherwise stated.

[067] The ingredients used are as identified in Table 1 of Example 1, except for the quantities and unless otherwise specified.

Propriedades
Propriedades de Manuseio Preditivas da Banda de Rodagem de Pneu Módulo de armazenagem curado (G’)1 a 100°C, 11 Hertz (RPA)1

Propriedades Preditivas de Resistência ao Rolamento da Banda de Rodagem de Pneu
(Os valores maiores para a elasticidade e os valores menores para a Tan Delta são preditivos da redução benéfica na resistência ao rolamento do pneu)

Propriedade de Tração a Úmido Preditiva da Banda de Rodagem de Pneu

Propriedade Preditiva do Desgaste da Banda de Rodagem de Pneu Resistência à Abrasão (Taxa de abrasão) (Menor é melhor)

Resistência ao Rasgo3, (resistência de peal) N

1, 2, 3Procedimentos de teste como no Exemplo I[068] Table 4 below illustrates the curing behavior and the various physical properties of rubber compositions based on the compounds in Table 3. Where cured rubber samples are examined, such as for strain-strain, values of elasticity and hot hardness, the rubber samples were cured for about 12 minutes, at a temperature of about 170 ° C.

properties
Predictive Handling Properties of Tire Tread Cured storage module (G ') 1 at 100 ° C, 11 Hertz (RPA) 1

Predictive Properties of Tire Tread Resistance
(Higher values for elasticity and lower values for Tan Delta are predictive of the beneficial reduction in tire rolling resistance)

Predictive Wet Traction Property of Tire Tread

Predictive Property of Tire Tread Wear Abrasion Resistance (Abrasion Rate) (Smaller is Better)

Tear resistance3, (peal resistance) N

1, 2, 3Test procedures as in Example I

[069] It can be seen in Table 4 that the low hardness of cold deformation of the Rubber Sample (Compound) C, the control, can be significantly increased with only a modest penalty for hysteresis, as indicated by the elasticity and as indicated by the physical properties of tan delta, by adding low levels of untreated precipitated silica (therefore hydrophilic precipitated silica), in Compounds (Rubber Samples) D, E and F.

[070] This is considered to be significant in a sense that it is possible to take advantage, therefore, of the low hysteresis properties of the rubber promoted by the pre-treated precipitated silica (pre-hydrophobized precipitated silica), through small additions of the silica hydrophilic precipitate, with an improvement resulting from the low hardness properties of cold deformation, which is significant to promote the wet and dry handling performance of the tire for a tire tread.

EXAMPLE III

[071] Conducted experiments to evaluate the effect of adding untreated precipitated silica to hydrophobized, pretreated, precipitated silica in the internal rubber mixer (Banbury mixer), combined with the addition of coupling agent to the compounds (Samples rubber). The compound (Rubber sample) G, the control, contained 84 phr of the pre-treated precipitated silica (pre-hydrophobized precipitated silica), while the compound (Rubber sample) H contained 63 phr of the pre-treated, hydro precipitated silica. phobized, and 20 phr of untreated precipitated silica (therefore hydrophilic precipitated silica) and 1.6 phr of coupling agent. Compound (Rubber Sample) I contained 42 phr of the pre-treated, pre-hydrophobized precipitated silica and 40 phr of the untreated precipitated silica added (therefore, hydrophilic precipitated silica added) and 3.2 phr of coupling. All compounds (rubber samples) contained a total of 80 phr of silica.

[072] This example represents an attempt to increase the low cold deformation hardness of the compound (rubber composition) containing pre-treated precipitated silica (pre-hydrophobized precipitated silica) by the addition of two levels of untreated precipitated silica ( hydrophilic precipitated silica), and by the addition of coupling agent. The success of this approach illustrates an ability to increase the low hardness of cold deformation, without a feather meaning for hysteresis, which is desired to be low in order to improve the rolling resistance of the tire.

[073] Table 5 below illustrates a basic formulation for the First Non-Productive Mixing Stage for rubber Samples, with parts presented by weight.

[074] The ingredients used are as identified in Table 1 of Example 1, except for the quantities and unless otherwise specified.

Propriedades
Propriedades de Manuseio Preditivas da Banda de Rodagem de Pneu Módulo de armazenagem curado (G’)1 a 100°C, 11 Hertz (RPA)1

Propriedades Preditivas de Resistência ao Rolamento da Banda de Rodagem de Pneu
(Os valores maiores para a elasticidade e os valores menores para a Tan Delta são preditivos da redução benéfica na resistência ao rolamento do pneu)

Propriedade de Tração a Úmido Preditiva da Banda de Rodagem de Pneu

Resistência à Abrasão (Taxa de abrasão) (Menor é melhor)

Resistência ao Rasgo3, (resistência de peal) N

1, 2, 3Procedimentos de teste como no Exemplo I[075] Table 6 below illustrates the curing behavior and the various physical properties of rubber compositions based on the basic formula in Table 5. Where cured rubber samples are examined, such as for strain-strain, values of elasticity and hot hardness, the rubber samples were cured for about 12 minutes, at a temperature of about 170 ° C.

properties
Predictive Handling Properties of Tire Tread Cured storage module (G ') 1 at 100 ° C, 11 Hertz (RPA) 1

Predictive Properties of Tire Tread Resistance
(Higher values for elasticity and lower values for Tan Delta are predictive of the beneficial reduction in tire rolling resistance)

Predictive Wet Traction Property of Tire Tread

Abrasion Resistance (Abrasion Rate) (Smaller is better)

Tear resistance3, (peal resistance) N

1, 2, 3Test procedures as in Example I

[076] It can be seen in Table 6 that the low cold deformation hardness of Compound (Rubber sample) G, the control, can be significantly increased without any penalty for hysteresis, as measured by elasticity and tan delta, by adding of untreated precipitated silica (hydrophilic precipitated silica) and coupling agent, for experimental compounds (rubber samples) H and I.

[077] This is considered to be significant in a sense that it is possible to take advantage of the low hysteresis properties promoted by the pre-treated precipitated silica (pre-hydrophobized precipitated silica), while improving the low deformation hardness properties. of the rubber composition, which are important for promoting the wet and dry handling performance of the tire for a tire tread.

EXAMPLE IV

• (A) Combinação de sílica precipitada pré-tratada, (pré-hidrofobizada), ou
• (B) Combinação de sílica precipitada pré-tratada, (pré-hidrofobizada), agente de acoplamento de sílica e sílica precipitada não tratada (sílica precipitada hidrofílica).

[078] Experiments were conducted to evaluate the effect of adding a resin product formed in situ (formed in the rubber composition) of methylene receptor and methylene donor to the rubber composition containing the functionalized elastomer and:

• (A) Combination of pre-treated precipitated silica, (pre-hydrophobized), or
• (B) Combination of pre-treated precipitated silica, (pre-hydrophobized), silica coupling agent and untreated precipitated silica (hydrophilic precipitated silica).

[079] The Rubber Compound (Rubber Sample) J, the control, contained 84 phr of the pre-treated precipitated silica (hydrophobized), while the compound (Rubber Sample) K contained 84 phr of the pre-treated precipitated silica (hydrophobized). ) and 1.75 phr of a resin product formed in situ of methylene receptor and methylene donor, and compound (Rubber sample) L contained 84 phr of pre-treated (hydrophobized) precipitated silica combined with 3.5 phr of the resin product. Compound (Rubber Sample) M contained 63 phr of pre-treated (hydrophobic) precipitated silica and 20 phr of untreated (hydrophilic) precipitated silica and 1.6 phr of coupling agent. Compound (Rubber sample) N was similar to Compound (Rubber sample) M, except that it also contained 3.5 phr of the resin product. All compounds (rubber samples) contained a total of 80 phr of precipitated silica.

[080] Table 7 below illustrates a basic formulation for the First Non-Productive Mixing Stage for rubber Samples, with parts presented by weight.

[081] The ingredients used are as identified in Table 1 of Example 1, except for the quantities and unless otherwise specified.
10 Methylene receptor as a reactive phenol / formaldehyde resin like HRJ-15873 ™ from SI Group, and methylene donor like hexametoxymethyl melamine resin like Cyrez CRA100 ™ from Cyrez.

Propriedades de Manuseio Preditivas da Banda de Rodagem de Pneu Módulo de armazenagem curado (G’)1 a 100°C, 11 Hertz (RPA)1

Propriedades Preditivas de Resistência ao Rolamento da Banda de Rodagem de Pneu
(Os valores maiores para a elasticidade e os valores menores para a Tan Delta são preditivos da redução benéfica na resistência ao rolamento do pneu)

Propriedade de Tração a Úmido Preditiva da Banda de Rodagem de Pneu

Resistência à Abrasão (Taxa de abrasão) (Menor é melhor)

Resistência ao Rasgo3, (resistência de peal) N

1, 2, 3Procedimentos de teste como no Exemplo I[082] Table 8 below illustrates the curing behavior and the various physical properties of rubber compositions based on the basic formula in Table 7. Where cured rubber samples are examined, such as for strain-strain, values of elasticity and hot hardness, the rubber samples were cured for about 12 minutes, at a temperature of about 170 ° C.

Predictive Handling Properties of Tire Tread Cured storage module (G ') 1 at 100 ° C, 11 Hertz (RPA) 1

Predictive Properties of Tire Tread Resistance
(Higher values for elasticity and lower values for Tan Delta are predictive of the beneficial reduction in tire rolling resistance)

Predictive Wet Traction Property of Tire Tread

Abrasion Resistance (Abrasion Rate) (Smaller is better)

Tear resistance3, (peal resistance) N

1, 2, 3Test procedures as in Example I

[083] It can be seen in Table 8 that the low cold deformation hardness of Compound (Rubber sample) J, the control, can be significantly increased without any penalty for hysteresis, as indicated by the elasticity and tan delta properties, by adding the resin product formed in situ of methylene receptor and methylene donor, as illustrated by Compounds (Rubber Samples) K and L or by using a combination of untreated precipitated silica (hydrophilic) and silane coupling agent , together with the resin product formed in situ, as illustrated by Compound (Rubber sample) N.

[084] This is considered to be significant in a sense that it is possible to take advantage of the low hysteresis properties promoted by the pre-treated (hydrophobic) precipitated silica, while improving the low hardness properties of cold deformation, which they are important to promote wet and dry tire performance for a tire tread.

EXAMPLE V

[085] Experiments were conducted to evaluate the effect of adding short fibers to the pre-treated (pre-hydrophobized) precipitated silica in the internal rubber mixer (Banbury mixer). The compound (Rubber sample) O, the control, contained 84 phr of the pre-treated (hydrophobized) precipitated silica, while the compounds (Rubber samples) P and Q contained 2 and 4 phr, respectively, of different short fibers. All compounds (rubber samples) contained a total of 80 phr of precipitated silica.

[086] The basic formulation for Rubber Samples O, P and Q is shown in Table 9 below, expressed in parts by weight per 100 parts of rubber (phr), unless otherwise specified.

[087] Ingredients used as identified in Table 1 of Example I, except that they can be otherwise identified and an inclusion of 2 and 4 phr of short fiber in the compounds (Rubber samples) P and Q.

Propriedades
Propriedades de Manuseio Preditivas da Banda de Rodagem de Pneu Módulo de armazenagem curado (G’)1
a 30°C, 10 Hertz (ARES)

Propriedades Preditivas de Resistência ao Rolamento da Banda de Rodagem de Pneu
(Os valores maiores para a elasticidade e os valores menores para a Tan Delta são preditivos da redução benéfica na resistência ao rolamento do pneu)

Propriedade de Tração a Úmido Preditiva da Banda de Rodagem de Pneu

Resistência à Abrasão (Taxa de abrasão) (Menor é melhor)

Resistência ao Rasgo3, (resistência de peal) N

1 2’ 3Procedimentos de teste como no Exemplo I, exceto o teste de ARES para a dureza de deformação a frio[088] Table 10 below illustrates the curing behavior and the various physical properties of the rubber compositions based on the basic formula in Table 7. Where cured rubber samples are examined, such as for strain-strain, values of elasticity and hot hardness, the rubber samples were cured for about 12 minutes, at a temperature of about 170 ° C.

properties
Predictive Handling Properties of Tire Tread Cured storage module (G ') 1
at 30 ° C, 10 Hertz (ARES)

Predictive Properties of Tire Tread Resistance
(Higher values for elasticity and lower values for Tan Delta are predictive of the beneficial reduction in tire rolling resistance)

Predictive Wet Traction Property of Tire Tread

Abrasion Resistance (Abrasion Rate) (Smaller is better)

Tear resistance3, (peal resistance) N

1 2 '3Test procedures as in Example I, except the ARES test for cold deformation hardness

[089] It can be seen in Table 10 that the low hardness of cold deformation (modulus G 'in deformation of 1 percent) of the Compound (Rubber sample) O, the control, can be significantly increased with some penalty for hysteresis , as indicated by the elasticity and tan delta properties, by the addition of the short fibers (Kevlar fibers) to the compound (Rubber sample) containing the pre-treated (thus pre-hydrophobized) precipitated silica.

[090] This is considered to be significant in a sense that it is possible to take advantage of some of the low hysteresis properties (evidenced by the elasticity and tan delta properties) of the rubber composition, promoted by the pre-treated precipitated silica (hydrophobized) ), while perfecting the low hardness properties of cold deformation (module G '), which are important for promoting the wet and dry handling performance of the tire for a tire tread.

[091] Although certain representative modalities and details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in this technique that various changes and modifications can be made to it, without departing from the spirit or scope of the invention.

Claims (1)

Rubber composition composed of, based on parts by weight per 100 parts by weight of rubber (phr), FEATURED for comprising:
(A) 100 phr of at least one diene-based elastomer composed of:
a polymerization combination of an organic solvent solution prepared from tin-coupled functionalized styrene / butadiene elastomer and at least one non-functionalized diene-based elastomer, wherein said combination contains more than 50 percent (by weight) of ( said styrene / butadiene elastomer (s) coupled to functionalized tin, and
(B) about 30 to about 120 phr of reinforcement charge composed of carbon reinforcing carbon black and precipitated silica composed of a combination of pre-hydrophobized precipitated silica and added hydrophilic precipitated silica without added silica coupler,
wherein said pre-hydrophobized precipitated silica is hydrophobized prior to its addition to the rubber composition by treatment with:

• (1) at least one of alkylsilane and alkoxysilane, or
• (2) a combination of at least one of alkylsilane and alkoxysilane together with at least one of an organoalkoxysilyl and organomercapto-alkoxysilane polysulfide, or
• (3) at least one of an organoalkoxysilyl and organomercap-toalcoxysilane polysulfide,

wherein said additional non-functional diene-based elastomer is composed of at least one of cis 1,4-polyisoprene, 1,4-polybutadiene and styrene / butadiene rubber; and
wherein said functional groups for said functionalized styrene / butadiene elastomer coupled to tin are constituted by a combination of thiol and siloxy functional groups reactive with the hydroxyl groups on said precipitated silica.