WO2016148144A1

WO2016148144A1 - Rubber composition and tire

Info

Publication number: WO2016148144A1
Application number: PCT/JP2016/058163
Authority: WO
Inventors: 加藤　学; 亮太高橋; 隆裕岡松; 美昭桐野
Original assignee: 横浜ゴム株式会社
Priority date: 2015-03-18
Filing date: 2016-03-15
Publication date: 2016-09-22
Also published as: JPWO2016148144A1

Abstract

The purpose of the present invention is to provide a rubber composition having excellent low exothermic properties and rigidity and toughness after vulcanization, and a tire which uses the rubber composition. This rubber composition contains a diene rubber and silica, the diene rubber including a modified polymer obtained by reacting a nitrone compound with double bonds of a conjugated diene polymer, the nitrone compound being a nitrone compound having an acetal structure, the content of the modified polymer in the diene rubber being 8-100% by mass, and the silica content being 25-130 parts by mass with respect to 100 parts by mass of the diene rubber.

Description

Rubber composition and tire

The present invention relates to a rubber composition and a tire.

Conventionally, a rubber composition containing a modified polymer using a compound having a nitrone group (nitrone compound) as a modifier is known as a rubber composition used for tires and the like.
For example, claim 1 of Patent Document 1 includes a rubber composition in which 10 to 120 parts by weight of silica is blended with 100 parts by weight of a diene rubber containing 5 to 100% by weight of a modified butadiene rubber, Is a rubber composition obtained by modifying a butadiene rubber having a cis content of 90% or more with a nitrone compound having a nitrogen-containing heterocyclic ring in the molecule. Patent Document 1 shows that heat generation is reduced by using the rubber composition described in Patent Document 1.

JP 2013-32471 A

Recently, from the viewpoint of environmental problems and the like, improvement in fuel efficiency is required, and accordingly, further reduction in heat generation is required. Further, as the required level of durability for tires increases, further improvements in rigidity and toughness after vulcanization are required for rubber compositions.
Under these circumstances, the present inventors examined the rubber composition described in Patent Document 1 and found that its low heat build-up does not necessarily satisfy the level required recently.

Therefore, in view of the above circumstances, an object of the present invention is to provide a rubber composition excellent in rigidity, toughness and low heat build-up after vulcanization, and a tire using the rubber composition.

As a result of intensive studies on the above problems, the present inventors have found that the above problems can be solved by using a nitrone compound having an acetal structure as a modifying agent, and have reached the present invention.
That is, the present inventors have found that the above problem can be solved by the following configuration.

(1) containing a diene rubber and silica,
The diene rubber includes a modified polymer obtained by reacting a nitrone compound with a double bond of a conjugated diene polymer,
The nitrone compound is a nitrone compound having an acetal structure,
The content of the modified polymer in the diene rubber is 8 to 100% by mass,
A rubber composition, wherein the content of silica is 25 to 130 parts by mass with respect to 100 parts by mass of the diene rubber.
(2) The rubber composition according to (1), wherein the nitrone compound is N-phenyl-α- (3,4-methylenebisoxyphenyl) nitrone.
(3) The rubber composition according to the above (1) or (2), wherein the modification rate of the modified polymer is 0.02 to 4.0 mol%. Here, the modification rate represents the ratio (mol%) modified by the nitrone compound among all the double bonds derived from the conjugated diene of the conjugated diene polymer.
(4) The amount of the nitrone compound reacted with respect to the double bond of the conjugated diene polymer is 0.1 to 10 parts by mass with respect to 100 parts by mass of the diene rubber. The rubber composition according to any one of (3).
(5) A tire manufactured using the rubber composition according to any one of (1) to (4) above.

As described below, according to the present invention, it is possible to provide a rubber composition excellent in rigidity, toughness and low heat build-up after vulcanization, and a tire using the rubber composition.

It is a partial section schematic diagram of the tire showing an example of an embodiment of a tire of the present invention.

Below, the rubber composition of this invention and the tire which used the rubber composition of this invention are demonstrated.
In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Rubber composition]
The rubber composition of the present invention (hereinafter also referred to as the composition of the present invention) contains a diene rubber and silica. Here, the diene rubber includes a modified polymer obtained by reacting a nitrone compound with a double bond of a conjugated diene polymer, the nitrone compound is a nitrone compound having an acetal structure, and the diene rubber The content of the modified polymer is 8 to 100% by mass, and the content of the silica is 25 to 130 parts by mass with respect to 100 parts by mass of the diene rubber.
Since the composition of this invention takes such a structure, it is thought that it is excellent in the rigidity after a vulcanization, toughness, and low exothermic property. The reason is not clear, but it is presumed that it is as follows.

As described above, the composition of the present invention contains a modified polymer obtained by reacting a nitrone compound with a double bond of a conjugated diene polymer. Therefore, the nitrone residue (modified nitrone group) in the modified polymer interacts with the silica in the composition to form a dense and homogeneous network between the silica and the polymer, resulting in improved rigidity and toughness. It is considered a thing. Moreover, since a homogeneous structure is formed as described above, it is considered that energy loss is reduced and low heat build-up is improved.
Here, if the interaction between the nitrone compound and silica is too strong, the balance between rigidity and toughness is reduced. In the present invention, since the nitrone compound having an acetal structure is used as the nitrone compound, It is considered that the interaction is adjusted to an appropriate size by the acetal structure, and as a result, the balance between rigidity and toughness is ensured.

[Diene rubber]
The diene rubber contained in the composition of the present invention includes a modified polymer obtained by reacting a nitrone compound with a double bond of a conjugated diene polymer. Here, the nitrone compound has an acetal structure. The content of the modified polymer in the diene rubber is 8 to 100% by mass.
The diene rubber may contain a rubber component other than the modified polymer. The rubber component is not particularly limited, but natural rubber, isoprene rubber (IR), butadiene rubber (BR), aromatic vinyl-conjugated diene copolymer rubber (for example, styrene butadiene rubber (SBR)), acrylonitrile-butadiene. Examples thereof include copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), and chloroprene rubber (CR). Of these, butadiene rubber (BR) and styrene butadiene rubber (SBR) are preferable.

<Modified polymer>
The modified polymer is a modified polymer obtained by reacting a nitrone compound having an acetal structure (hereinafter also referred to as “acetal nitrone”) with a double bond of a conjugated diene polymer.

(Conjugated diene polymer)
The conjugated diene polymer used in the production of the modified polymer is not particularly limited, and natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), aromatic vinyl-conjugated diene copolymer rubber (for example, styrene) Examples thereof include butadiene rubber (SBR), acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), and chloroprene rubber (CR). Of these, styrene butadiene rubber (SBR) and butadiene rubber (BR) are preferable. That is, the modified polymer is preferably a modified polymer obtained by reacting a nitrone compound with a double bond of styrene butadiene rubber (SBR) or butadiene rubber (BR).

(Nitron compounds)
The nitrone compound used for the production of the modified polymer is not particularly limited as long as it is a nitrone compound having an acetal structure (acetal nitrone). Here, the nitrone compound refers to a compound having a nitrone group represented by the following formula (1).

In the above formula (1), * represents a bonding position.

The acetal nitrone is preferably a compound represented by the following formula (2).

In the above formula (2), X and Y each independently represent an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or an aromatic heterocyclic group that may have an acetal structure. However, at least one of X and Y has an acetal structure (preferably, it has an acetal structure as a substituent).
Examples of the aliphatic hydrocarbon group include an alkyl group, a cycloalkyl group, and an alkenyl group. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, Examples thereof include a tert-pentyl group, 1-methylbutyl group, 2-methylbutyl group, 1,2-dimethylpropyl group, n-hexyl group, n-heptyl group, and n-octyl group. Are preferred, and alkyl groups having 1 to 6 carbon atoms are more preferred. Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, etc. Among them, a cycloalkyl group having 3 to 10 carbon atoms is preferable, and a cycloalkyl group having 3 to 6 carbon atoms is preferable. More preferred. Examples of the alkenyl group include a vinyl group, a 1-propenyl group, an allyl group, an isopropenyl group, a 1-butenyl group, and a 2-butenyl group. Among them, an alkenyl group having 2 to 18 carbon atoms is preferable. An alkenyl group having 2 to 6 carbon atoms is more preferable.
Examples of the aromatic hydrocarbon group include an aryl group and an aralkyl group. Examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a biphenyl group. Among them, an aryl group having 6 to 14 carbon atoms is preferable, and an aryl group having 6 to 10 carbon atoms is more preferable. A phenyl group and a naphthyl group are more preferable. Examples of the aralkyl group include a benzyl group, a phenethyl group, and a phenylpropyl group. Among them, an aralkyl group having 7 to 13 carbon atoms is preferable, an aralkyl group having 7 to 11 carbon atoms is more preferable, and a benzyl group is preferable. Further preferred.
Examples of the aromatic heterocyclic group include pyrrolyl group, furyl group, thienyl group, pyrazolyl group, imidazolyl group (imidazole group), oxazolyl group, isoxazolyl group, thiazolyl group, isothiazolyl group, pyridyl group (pyridine group), furan Group, thiophene group, pyridazinyl group, pyrimidinyl group, pyrazinyl group and the like.

The acetal structure represents a structure represented by the following formula (A).

In the above formula (A), R ₁ to R ₄ each independently represents a hydrogen atom or a hydrocarbon group.
Examples of the hydrocarbon group include an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a group obtained by combining these.
The aliphatic hydrocarbon group may be linear, branched or cyclic. Specific examples of the aliphatic hydrocarbon group include a linear or branched alkyl group (particularly 1 to 30 carbon atoms), a linear or branched alkenyl group (particularly 2 to 30 carbon atoms), Examples thereof include a linear or branched alkynyl group (particularly 2 to 30 carbon atoms).
Examples of the aromatic hydrocarbon group include aromatic hydrocarbon groups having 6 to 18 carbon atoms such as a phenyl group, a tolyl group, a xylyl group, and a naphthyl group.

Note that “having an acetal structure” intends to have an n-valent group obtained by removing n (n is an integer of 1 or more) hydrogen atoms from the structure represented by the above formula (A). To do.

A preferred embodiment of acetal nitrone includes a compound represented by the following formula (A1).

In the above formula (A1), R ₁ to R ₂ and R ₄ each independently represents a hydrogen atom or a hydrocarbon group. Specific examples and preferred embodiments of R ₁ to R ₂ and R ₄ are the same as R ₁ to R _{4 in} formula (A) described above. R ₄ may be bonded to a benzene ring to which L is bonded to form a ring. L represents a single bond or a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include a divalent hydrocarbon group obtained by removing one hydrogen atom from the above-described hydrocarbon group.

The compound represented by the formula (A1) is preferably a compound represented by the following formula (A2). The compound represented by the following formula (A2) corresponds to an embodiment in which R ₄ in the above formula (A1) is bonded to a benzene ring to which L is bonded to form a ring.

In the above formula (A2), R ₁ and R ₂ each independently represents a hydrogen atom or a hydrocarbon group. Specific examples and preferred embodiments of R ₁ ~ _{R 2} are the same as _R 1 ~ _{R 4} in the above-mentioned formula (A). L represents a single bond or a divalent hydrocarbon group. Specific examples and preferred embodiments of L are the same as L in Formula (A1) described above. Plural Ls may be the same or different.

The compound represented by the above formula (A2) is preferably a compound represented by the following formula (A3). Note that the compound represented by the following formula (A3) corresponds to an embodiment in which L in the above formula (A2) is a single bond and is bonded to the 3rd and 4th positions of the benzene ring.

In the above formula (A3), R ₁ and R ₂ each independently represents a hydrogen atom or a hydrocarbon group. Specific examples and preferred embodiments of R ₁ ~ _{R 2} are the same as _R 1 ~ _{R 4} in the above-mentioned formula (A).

Examples of the compound represented by the formula (A3) include N-phenyl-α- (3,4-methylenebisoxyphenyl) nitrone (an embodiment in which R ₁ and R ₂ in the formula (A3) are hydrogen atoms). Is mentioned.

The method for synthesizing the acetal nitrone is not particularly limited, and a conventionally known method can be used. For example, a compound having a hydroxyamino group (—NHOH), a compound having an aldehyde group (—CHO) and an acetal structure (for example, piperonal represented by the formula (b) described later), a hydroxyamino group and an aldehyde group By stirring for 1 to 24 hours at room temperature under an organic solvent (eg, methanol, ethanol, tetrahydrofuran, etc.) in such an amount that the molar ratio of (—NHOH / —CHO) becomes 1.0 to 1.5. Both groups react to give a compound having an acetal structure and a nitrone group (acetal nitrone).

(Method for producing modified polymer)
A method for producing a modified polymer by reacting an acetal nitrone with a double bond of a conjugated diene polymer is not particularly limited. For example, the above-described conjugated diene polymer and the above-described nitrone compound are heated at 100 to 200 ° C. And mixing for 1 to 30 minutes.
At this time, as shown in the following formula (4-1) or the following formula (4-2), between the double bond derived from the conjugated diene of the conjugated diene polymer and the nitrone group of the acetal nitrone, A cycloaddition reaction takes place, giving a five-membered ring. The following formula (4-1) represents a reaction between a 1,4-bond and a nitrone group, and the following formula (4-2) represents a reaction between a 1,2-vinyl bond and a nitrone group. Formulas (4-1) and (4-2) represent reactions when butadiene is 1,3-butadiene, but when butadiene is other than 1,3-butadiene, Give a ring.

The amount of acetal nitrone reacted with respect to the double bond of the conjugated diene polymer is preferably 0.1 to 10 parts by mass, and 0.3 to 5 parts by mass with respect to 100 parts by mass of the diene rubber. More preferably, the amount is 1 to 3 parts by mass.

(Modification rate)
The modification rate of the modified polymer is not particularly limited, but is preferably 0.02 to 4.0 mol%, and more preferably 0.10 to 2.0 mol%.
Here, the modification rate represents the ratio (mol%) modified by the nitrone compound among all the double bonds derived from the conjugated diene (conjugated diene diene unit) of the conjugated diene polymer. Is butadiene (1,3-butadiene), it represents the ratio (mol%) in which the structure of the above formula (4-1) or the above formula (4-2) is formed by modification with a nitrone compound. The modification rate can be determined, for example, by performing NMR measurement of the conjugated diene polymer and modified polymer (that is, the polymer before and after modification).
In the present specification, a modified polymer having a modification rate of 100 mol% also corresponds to a diene rubber.

The content of the modified polymer in the diene rubber is 8 to 100% by mass. In particular, the content is more preferably 20 to 80% by mass, and more preferably 30 to 50% by mass.
〔silica〕
The composition of the present invention contains silica.
Although the said silica in particular is not restrict | limited, The conventionally well-known arbitrary silica currently mix | blended with the rubber composition for uses, such as a tire, can be used.
Specific examples of silica include wet silica, dry silica, fumed silica, diatomaceous earth, and the like. Of these, wet silica is preferable. As the silica, one type of silica may be used alone, or two or more types of silica may be used in combination.

In the composition of the present invention, the content of silica is 25 to 130 parts by mass with respect to 100 parts by mass of the diene rubber. In particular, the amount is more preferably 40 to 100 parts by mass.

[Optional ingredients]
The composition of this invention can contain an additive further in the range which does not impair the effect and objective as needed.
Examples of the additive include fillers other than silica (for example, carbon black), silane coupling agents, zinc oxide (zinc white), stearic acid, adhesive resins, peptizers, anti-aging agents, waxes, Various additives generally used in rubber compositions such as processing aids, aroma oils, liquid polymers, terpene resins, thermosetting resins, vulcanizing agents (for example, sulfur), and vulcanization accelerators can be mentioned. .

[Method for producing rubber composition]
The production method of the composition of the present invention is not particularly limited, and specific examples thereof include, for example, kneading the above-described components using a known method and apparatus (for example, a Banbury mixer, a kneader, a roll, etc.). The method etc. are mentioned. When the composition of the present invention contains sulfur or a vulcanization accelerator, components other than sulfur and the vulcanization accelerator are first mixed at a high temperature (preferably 80 to 140 ° C.) and cooled, and then sulfur or It is preferable to mix a vulcanization accelerator.
The composition of the present invention can be vulcanized or crosslinked under conventionally known vulcanization or crosslinking conditions.

[Use]
The composition of the present invention is suitably used for tires (preferably cap tread portions).

[tire]
The tire of the present invention is a tire using the above-described composition of the present invention. Especially, it is preferable that it is a pneumatic tire which used the composition of this invention for the tire tread part (cap tread part).
FIG. 1 shows a schematic partial sectional view of a tire representing an example of an embodiment of the tire of the present invention, but the tire of the present invention is not limited to the embodiment shown in FIG.

In FIG. 1, reference numeral 1 represents a bead portion, reference numeral 2 represents a sidewall portion, and reference numeral 3 represents a tire tread portion.
Further, a carcass layer 4 in which fiber cords are embedded is mounted between the pair of left and right bead portions 1, and the end of the carcass layer 4 extends from the inside of the tire to the outside around the bead core 5 and the bead filler 6. Wrapped and rolled up.
Further, in the tire tread portion 3, a belt layer 7 is disposed over the circumference of the tire on the outside of the carcass layer 4.
Moreover, in the bead part 1, the rim cushion 8 is arrange | positioned in the part which touches a rim | limb.
The tire tread portion 3 is formed of the above-described composition of the present invention.

The tire of the present invention can be manufactured, for example, according to a conventionally known method. Moreover, as gas with which a tire is filled, inert gas, such as nitrogen, argon, helium other than the air which adjusted normal or oxygen partial pressure, can be used.

Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

<Synthesis of Acetal Nitron>
Piperonal (30.0 g) represented by the following formula (b) and ethanol (20 mL) are placed in a 300 mL eggplant flask, and phenylhydroxyamine (21.8 g) represented by the following formula (a) is added to ethanol. What was dissolved in (70 mL) was added, and it stirred at room temperature for 22 hours. After completion of the stirring, the nitrone compound (acetal nitrone) represented by the following formula (c) was obtained as white crystals by recrystallization from ethanol (42.9 g). The yield was 89%.

<Synthesis of diphenylnitrone>
A 300 mL eggplant flask is charged with benzaldehyde (42.45 g) represented by the following formula (6) and ethanol (10 mL), and phenylhydroxyamine (43.65 g) represented by the following formula (5) is added to ethanol. What was dissolved in (70 mL) was added, and it stirred at room temperature for 22 hours. After completion of the stirring, recrystallization from ethanol gave a nitrone compound (diphenylnitrone) having no acetal structure represented by the following formula (7) as white crystals (65.40 g). The yield was 83%.

<Synthesis of pyridyl nitrone>
Methanol (900 mL) warmed to 40 ° C. was placed in a 2 L eggplant flask, and 2-pyridinecarboxaldehyde (21.4 g) represented by the following formula (b-2) was added and dissolved therein. To this solution was added phenylhydroxyamine (21.8 g) represented by the following formula (a-2) dissolved in methanol (100 mL), and the mixture was stirred at room temperature for 19 hours. After the stirring, the nitrone compound (pyridyl nitrone) represented by the following formula (c-2) was obtained by recrystallization from methanol (39.0 g). The yield was 90%.

<Synthesis of Modified Polymer (Modified Polymer 1)>
SBR (Nipol 1502 manufactured by Nippon Zeon Co., Ltd.) was charged into a Banbury mixer at 120 ° C. and masticated for 2 minutes. Thereafter, 1.22 parts by mass of the acetal nitrone synthesized as described above was added to 100 parts by mass of SBR and mixed at 160 ° C. for 5 minutes to modify SBR with acetal nitrone. The resulting modified polymer is referred to as modified polymer 1.
The obtained modified polymer 1 was subjected to NMR measurement to obtain a modification rate. The modification rate of the modified polymer 1 was 0.32 mol%.

<Synthesis of Modified Polymer (Modified Polymer 2)>
Instead of charging 1.22 parts by mass of acetal nitrone, SBR was modified with acetal nitrone according to the same procedure as modified polymer 1 except that 3.65 parts by mass was added. The resulting modified polymer is referred to as modified polymer 2.
The obtained modified polymer 2 was subjected to NMR measurement to determine the modification rate. The modification rate of the modified polymer 2 was 0.96 mol%.

<Synthesis of Comparative Modified Polymer 1>
SBR was modified with diphenylnitrone according to the same procedure as modified polymer 1 except that 3.65 parts by mass of diphenylnitrone synthesized as described above was used instead of acetal nitrone. The obtained SBR modified with diphenylnitrone is referred to as comparative modified polymer 1.
The obtained comparative modified polymer 1 was subjected to NMR measurement to obtain a modification rate. As a result, the modification rate of the comparative modified polymer 1 was 1.18 mol%.

<Synthesis of Comparative Modified Polymer 2>
SBR was modified with pyridyl nitrone according to the same procedure as modified polymer 1 except that 3.65 parts by mass of pyridyl nitrone synthesized as described above was used instead of acetal nitrone. The obtained SBR modified with pyridyl nitrone is referred to as comparative modified polymer 2.
The obtained comparative modified polymer 2 was subjected to NMR measurement to determine the modification rate. The modification rate of the comparative modified polymer 2 was 0.81 mol%.

<Preparation of rubber composition>
The components shown in Table 1 below were blended in the proportions (parts by mass) shown in Table 1 below.
Specifically, first, components excluding sulfur and a vulcanization accelerator among the components shown in Table 1 below were mixed for 5 minutes with a Banbury mixer at 80 ° C. Next, sulfur and a vulcanization accelerator were mixed using a roll to obtain a rubber composition.

<Preparation of vulcanized rubber sheet>
Each obtained rubber composition (unvulcanized) was press vulcanized at 160 ° C. for 15 minutes in a mold (15 cm × 15 cm × 0.2 cm) to produce a vulcanized rubber sheet.

<Evaluation>
(Modulus)
The produced vulcanized rubber sheet was cut into a dumbbell shape (dumbbell shape No. 3) having a thickness of 2 mm to obtain a test piece.
About the obtained test piece, 100% modulus (stress at the time of 100% elongation) [MPa] was measured according to JIS K6251: 2010. The results are shown in Table 1 (M100). The results were expressed as an index with Comparative Example 1 as 100. The larger M100, the better the rigidity.

(Elongation at break)
The produced vulcanized rubber sheet was cut into a dumbbell shape (dumbbell shape No. 3) having a thickness of 2 mm to obtain a test piece.
About the obtained test piece, elongation at break (= elongation at break) was measured under the conditions of a temperature of 20 ° C. and a pulling speed of 500 mm / min according to JIS K6251: 2010. The results are shown in Table 1 (Elongation at break). The results were expressed as an index with Comparative Example 1 as 100. The larger the elongation at break, the better the toughness.

(Low heat generation)
The produced vulcanized rubber sheet was subjected to loss tangent tanδ (60 ° C.) at a temperature of 60 ° C. using a viscoelastic spectrometer (manufactured by Toyo Seiki Seisakusho) under conditions of an initial strain of 10%, an amplitude of ± 2%, and a frequency of 20 Hz ) Was measured. The reciprocal of tan δ (60 ° C.) is shown in Table 1 (low exothermic property). In addition, it represented with the index | exponent which makes the reciprocal number of tan-delta (60 degreeC) of the comparative example 1 100. The larger the value, the better the low heat buildup.

In Table 1, the nitrone amount converted value represents the part by mass of the nitrone compound used for the synthesis of the modified polymer or the comparatively modified polymer with respect to 100 parts by mass of the diene rubber.
In Table 1, the modification rate represents the modification rate of the modified polymer described above.

The detail of each component shown by the said Table 1 is as follows.
・ SBR: Nipol 1502 (manufactured by Nippon Zeon)
-BR: Nipol BR1220 (manufactured by Nippon Zeon)
Modified polymer 1: Modified polymer 1 synthesized as described above
Modified polymer 2: Modified polymer 2 synthesized as described above
Comparative modified polymer 1: Comparative modified polymer 1 synthesized as described above
Comparative modified polymer 2: Comparative modified polymer 2 synthesized as described above
・ Carbon black: Show black N339 (manufactured by Cabot Japan)
Silica: ZEOSIL 165GR (manufactured by Rhodia Silica Korea)
・ Stearic acid: Stearic acid YR (manufactured by NOF Corporation)
Processing aid: Actiplast ST (manufactured by Rhein Chemie)
Anti-aging agent: SANTOFLEX 6PPD (manufactured by Soltia Europe)
・ Wax: Sunnock (Ouchi Shinsei Chemical Co., Ltd.)
・ Coupling agent: Si69 (Evonik Degussa)
・ Oil: Extract No. 4 S (made by Showa Shell Sekiyu KK)
・ Zinc flower: Zinc flower No. 3 (manufactured by Shodo Chemical Co., Ltd.)
・ Sulfur: Oil-treated sulfur (manufactured by Karuizawa Refinery)
・ Vulcanization accelerator CZ: Noxeller CZ-G (Ouchi Shinko Chemical Co., Ltd.)
・ Vulcanization accelerator DPG: Soxinol DG: (Sumitomo Chemical Co., Ltd.)

As can be seen from Table 1, Examples 1 and 2 containing a modified polymer obtained by reacting acetal nitrone with a double bond of a conjugated diene polymer showed excellent rigidity, toughness and low heat build-up. It was. Among them, Example 2 in which the modification rate of the modified polymer was 0.50 mol% or more showed more excellent rigidity, toughness, and low exothermic property.

On the other hand, Comparative Examples 1 to 3, which do not contain a modified polymer obtained by reacting an acetal nitrone with a double bond of a conjugated diene polymer, are insufficient in at least one of rigidity, toughness and low exothermic property. there were.

1 Bead part 2 Side wall part 3 Tire tread part 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 8 Rim cushion

Claims

Containing diene rubber and silica,
The diene rubber includes a modified polymer obtained by reacting a nitrone compound with a double bond of a conjugated diene polymer,
The nitrone compound is a nitrone compound having an acetal structure,
The content of the modified polymer in the diene rubber is 8 to 100% by mass,
A rubber composition, wherein a content of the silica is 25 to 130 parts by mass with respect to 100 parts by mass of the diene rubber.
The rubber composition according to claim 1, wherein the nitrone compound is N-phenyl-α- (3,4-methylenebisoxyphenyl) nitrone.
The rubber composition according to claim 1 or 2, wherein the modified polymer has a modification rate of 0.02 to 4.0 mol%. Here, the modification rate represents the ratio (mol%) modified by the nitrone compound among all the double bonds derived from the conjugated diene of the conjugated diene polymer.
The amount of the nitrone compound reacted with respect to the double bond of the conjugated diene polymer is 0.1 to 10 parts by mass with respect to 100 parts by mass of the diene rubber. The rubber composition according to item 1.
A tire manufactured using the rubber composition according to any one of claims 1 to 4.