JP2019104893A - Rubber composition, vulcanized rubber, belt coating rubber, intermediate rubber, and tire - Google Patents

Abstract

To provide a rubber composition capable of producing a vulcanized rubber achieving low heat generation property and resistance to crack propagation at high level; a vulcanized rubber, a belt coating rubber and an intermediate rubber which achieve low heat generation property and resistance to crack propagation at high level; and a tire achieving low loss property and resistance to crack propagation at high level.SOLUTION: A rubber composition contains a rubber component, carbon black having a ratio (NSA/IA) of a nitrogen adsorption specific area (NSA) m/g to an iodine adsorption amount (IA) mg/g of 1.2 m/mg or less, and a resin component containing a resin having an SP value of 10 (cal/cm)or more, in which a ratio of 200% modulus value (M200) to 50% modulus value (M50) after vulcanization is 5.0 or less (M200/M50≤5.0).SELECTED DRAWING: None

Description

  The present invention relates to a rubber composition, a vulcanized rubber, a belt coating rubber, an intermediate rubber and a tire.

  Generally, inside a tire requiring strength, a carcass layer composed of a cord embedded along a meridian direction of a ring-shaped tire main body, and a belt disposed on the tire radial direction outer side of the carcass layer And may be provided. This belt is usually formed of a plurality of belt layers in which a steel cord is covered with a coating rubber (hereinafter referred to as "belt coating rubber" or "coating rubber") to impart load resistance, traction resistance and the like to the tire. ing. And, with respect to belt coating rubber, high durability, particularly high resistance to crack propagation is required. On the other hand, in recent years, in order to reduce the rolling resistance of a tire from the viewpoint of improving the low fuel consumption performance of a car, a demand for improving the low loss property of a belt coating rubber is increasing.

However, when the amount of carbon black blended into the belt coating rubber is reduced to improve low loss properties, the crack extension resistance tends to deteriorate, so that low loss properties and crack extension resistance Development of technology that can achieve both is desired.
In order to solve the above problems, for example, Patent Document 1 discloses a technique for improving the dispersibility of surface-treated carbon black by producing a rubber composition using a wet masterbatch prepared using a specific grade of carbon black. It is disclosed.

Further, for example, Patent Document 2 includes a rubber for a tire for the purpose of improving steering stability when used in a tire to a level equal to or higher than a conventional level while reducing rolling resistance by blending carbon black whose colloidal characteristics are controlled. The composition is blended with 1 to 50 parts by weight of a novolak-type phenolic resin and a methylene donor in total with 100 parts by weight of a diene rubber and 60 to 100 of a reinforcing filler containing 30 to 100 parts by weight of carbon black. A rubber composition for a tire, which is compounded in parts by weight, which has a mode diameter Dst of 145 nm or more, a nitrogen adsorption specific surface area N ₂ SA of 45 to 70 m ² / g, iodine, in the mass distribution curve of the Stokes diameter of the carbon black aggregate the ratio _N 2 SA / IA of the nitrogen adsorption specific surface area _N 2 SA for adsorption IA (units mg / g) is from 1.00 to 1 It is disclosed that is assumed to be 40.
Furthermore, for example, in Patent Document 3, a rubber composition for steel cords having improved heat buildup and breaking strength and improved adhesion to steel cords without deteriorating fatigue resistance, and air using the same and excellent durability. For the purpose of obtaining a radial tire containing the rubber composition for a steel cord, (A) nitrogen adsorption specific surface area (A) per 100 parts by weight of at least one rubber component selected from natural rubber and diene-based synthetic rubber N ₂ SA) is 70 to 100 m ² / g, (B) ratio of half value width (ΔDst) of Dst to most frequent value (Dst) of aggregate distribution, ΔDst / Dst is 0.85 to 1.25, (C) 24M4DBP oil absorption of 60~120ml / 100g, all conditions value from 1.10 to 1.35, of _{(D) N} 2 SA and iodine adsorption ratio of _{(IA) (N 2 SA /} IA) 35 to 65 parts by weight of soot carbon black, 0.1 to 0.3 parts by weight of cobalt salt of organic acid cobalt salt, 0.5 to 5 parts by weight of resorcinol or resorcinol derivative and hexamethylenetetramine as its methylene donor Alternatively, it is disclosed that the melamine derivative is contained in an amount of 0.5 to 2 parts by weight of the resorcin or resorcin derivative.

JP, 2016-037547, A JP 2014-37514 A JP, 2006-232895, A

According to the technology of Patent Document 1, it has become possible to obtain a compatible effect of constant low loss and crack propagation resistance. However, from the viewpoint of further improving the performance of the tire, higher levels of low loss and resistance to cracking have been desired.
Moreover, in the technique of patent document 2 and 3, the coexistence effect of low loss property and crack extension resistance was not acquired.

  Therefore, the present invention provides a rubber composition capable of producing a vulcanized rubber compatible with low heat buildup and crack propagation resistance at a high level, and a vulcanized rubber compatible with low heat buildup and crack propagation resistance at a high level It is an object of the present invention to provide a belt coating rubber, and an intermediate rubber, and a tire which is compatible with a high level of low loss and crack propagation resistance.

<1> rubber component,
A carbon black having a ratio of nitrogen adsorption specific surface area (N ₂ SA) m ² / g to iodine adsorption amount (IA) mg / g (N ₂ SA / IA) of 1.2 m ² / mg or less,
And a resin component containing a resin having an SP value of 10 (cal / cm ³ ) ^1/2 or more,
It is a rubber composition in which the ratio of 200% modulus value (M200) to 50% modulus value (M50) after vulcanization is 5.0 or less (M200 / M50 ≦ 5.0).

<2> The rubber composition according to <1>, wherein the resin component comprises a phenol resin and a methylene donor.
The content of the <3> said carbon black is a rubber composition as described in <1> or <2> which is 35-45 mass parts with respect to 100 mass parts of said rubber components.
<4> The rubber composition according to any one of <1> to <3>, further containing silica.
<5> The methylene donor according to any one of <2> to <4>, which is at least one selected from the group consisting of hexamethylenetetramine, hexamethoxymethylmelamine, hexamethoxymethylolmelamine and paraformaldehyde. Rubber composition of
<6> The content of the resin whose SP value is 10 (cal / cm ³ ) ^1/2 or more is 2 to 10 parts by mass with respect to 100 parts by mass of the rubber component <1> to <5> It is a rubber composition as described in any one of these.
The ratio of content of the said phenol resin with respect to content of the <7> above-mentioned methylene donor is a rubber composition as described in any one of <2>-<6> which is 0.6-7.

It is a vulcanized rubber using the rubber composition as described in any one of <8><1>-<7>.
<9> Ratio of loss tangent (tan δ _100% ) at 100% strain at 24 ° C to loss tangent (tan δ _1% ) at 1% strain at 24 ° C [tan δ _100% / tan δ _1% ] is 0.6 or more It is a vulcanized rubber as described in <8>.

It is a belt coating rubber using the vulcanized rubber as described in <10><8> or <9>.
It is an interval rubber using the vulcanized rubber as described in <11><8> or <9>.
The tire using the vulcanized rubber as described in <12><8> or <9>.

  According to the present invention, a rubber composition capable of producing a vulcanized rubber capable of achieving both low heat buildup and resistance to crack development at a high level, and a vulcanized rubber capable of achieving both low heat buildup and resistance to crack development at a high level It is possible to provide a belt coating rubber, and an intermediate rubber, and a tire compatible with a high level of low loss and crack propagation resistance.

<Rubber composition>
The rubber composition of the present invention has a rubber component and a ratio (N ₂ SA / IA) of nitrogen adsorption specific surface area (N ₂ SA) m ² / g to iodine adsorption amount (IA) mg / g 200% modulus with respect to 50% modulus value (M50) after vulcanization, including carbon black having ² / mg or less and a resin component containing a resin having an SP value of 10 (cal / cm ³ ) ^1/2 or more The ratio of the values (M200) is 5.0 or less (M200 / M50 ≦ 5.0). That is, in the rubber composition of the present invention, the ratio of 200% modulus value (M200) to 50% modulus value (M50) is 5.0 or less (M200 / M50 ≦ 5.0) as the vulcanized rubber characteristic. .
The resin gathers around the carbon black to form a network of carbon blacks through the resin, and it is considered that the vulcanized rubber obtained from the rubber composition can exhibit high fissility. . Here, carbon black usually has on its surface an oxygen-containing functional group such as a carboxy group, a hydroxy group or a quinone group. When the number of surface functional groups is large, the reactivity with the rubber component is increased, and the resin is less likely to gather around the carbon black, which tends to inhibit the network formation.
The low N ₂ SA / IA of carbon black means that the surface functional group number of carbon black is low (the polarity is low). When N ₂ SA / IA of carbon black is 1.2 m ² / mg or less, the reactivity between the rubber component and carbon black is suppressed, and network formation proceeds, so the crack propagation resistance of vulcanized rubber is excellent. it is conceivable that.

Further, the rubber composition of the present invention, by containing a resin, increases the 50% modulus value (M50) of the vulcanized rubber, reinforces the rubber composition while maintaining excellent low heat buildup, and is excellent Crack propagation resistance can be realized. In the rubber compositions shown in Patent Documents 2 and 3, carbon black having N ₂ SA / IA of 1.2 m ² / mg or less is also used, but since it does not contain a resin, excellent crack propagation resistance is obtained. It can not be realized.
Furthermore, a resin with an SP value (solubility parameter value, Solubility Parameter value) of less than 10 (cal / cm ³ ) ^1/2 is easily compatible with the rubber component, and therefore, forms a network between carbon blacks via the resin. Tend to inhibit.
In the present invention, by including a resin having an SP value of 10 (cal / cm ³ ) ^1/2 or more, the vulcanized rubber is excellent in low heat buildup and excellent in crack propagation resistance.

In the present invention, furthermore, the ratio of the 200% modulus value (M200) of the vulcanized rubber to the 50% modulus value (M50) of the vulcanized rubber is 5.0 or less (M200 / M50 ≦ 5.0). And low heat buildup and resistance to cracking of vulcanized rubber can be realized.
M50 is a parameter related to the elasticity in the low strain region, and the deformation of the belt portion of the tire can be suppressed as the value is larger. On the other hand, M200 is a parameter related to the elasticity in the high strain area, and the lower the value, the more the crack propagation of the vulcanized rubber can be suppressed, and the stress concentration at the crack tip can be relaxed.
Hereinafter, the details of the rubber composition of the present invention will be described.

[Rubber component]
The rubber composition of the present invention contains a rubber component.
The rubber component is not particularly limited, and can be appropriately changed according to the required performance. For example, from the viewpoint of obtaining excellent crack propagation resistance and wear resistance, the rubber composition may be a natural rubber or a diene-based synthetic rubber alone, or a combination of a natural rubber and a diene-based synthetic rubber. Can contain a rubber component.
The rubber component can also be composed of 100% of diene rubber, but may contain rubber other than diene rubber as long as the object of the present invention is not impaired. From the viewpoint of obtaining excellent crack propagation resistance, the content of the diene rubber in the rubber component is preferably 30% by mass or more, more preferably 40% by mass or more, and 50 It is more preferable that the content is at least mass%.

Here, as diene based synthetic rubber, polybutadiene rubber (BR), isoprene rubber (IR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), etc. Can be mentioned.
Further, as non-diene rubber, ethylene propylene diene rubber (EPDM), ethylene propylene rubber (EPM), butyl rubber (IIR) and the like can be mentioned.
These diene synthetic rubbers and non-diene rubbers may be used alone or in combination of two or more. The rubber component may be modified with a modifying group.
Among the above, the rubber component preferably includes at least one selected from the group consisting of natural rubber, polybutadiene rubber (BR), isoprene rubber (IR), and styrene butadiene rubber (SBR), and natural rubber and polybutadiene It is more preferable to include at least one selected from the group consisting of rubber (BR). When one rubber component is used alone, it is preferable to use one natural rubber or one styrene butadiene rubber, and it is more preferable to use one natural rubber. When using 2 or more types of rubber components in mixture, it is preferable to mix and use natural rubber and diene based synthetic rubber, and it is preferable to use 2 types of natural rubber and polybutadiene rubber in mixture.

〔Carbon black〕
The rubber composition of the present invention contains carbon black having a ratio (N ₂ SA / IA) of nitrogen adsorption specific surface area (N ₂ SA) to iodine adsorption amount (IA) of 1.2 m ² / mg or less.
N ₂ SA / IA is a value of nitrogen adsorption specific surface area (N ₂ SA) [m ² / g] with respect to iodine adsorption amount (IA) [mg / g], The unit of N ₂ SA / IA is [m ² / g] / [mg / g] = [m ² / mg].
When the value of N ₂ SA / IA is small, the number of surface functional groups of carbon black is small, the reactivity between the rubber component and carbon black is suppressed, and the formation of a network of carbon blacks through resin progresses, so vulcanized rubber Excellent in crack propagation resistance.
From the viewpoint of further enhancing the formation of a network between carbon blacks, the N ₂ SA / IA is preferably less than 1.10 m ² / mg, and more preferably 1.06 m ² / mg or less. Carbon blacks with N ₂ SA / IA smaller than 0.85 m ² / mg are difficult to obtain, and there is a certain degree of reactivity between the rubber component and the carbon black, which makes it possible to form a network between carbon blacks. it is possible to _increase, it is preferred that the N 2 SA / IA is 0.90 m ² / mg or more, more preferably 0.93 m ² / mg or more, it is 0.94 m ² / mg or more More preferable.

Nitrogen adsorption specific surface area _(N 2 SA) is preferably 70~90m ² / g, more preferably 75~85m ² / g. Since the carbon black structure can be optimized, low heat buildup and resistance to cracking can be further improved. Here, the structure of carbon black refers to the size of the formed structure (aggregates of carbon black particles) as a result of bonding and joining of spherical carbon black particles.
In addition, the nitrogen adsorption specific surface area can be measured by a single point method in accordance with ISO4652-1. For example, after immersing degassed carbon black in liquid nitrogen, it is adsorbed on the carbon black surface at the equilibrium time. The specific surface area (m ² / g) can be calculated from the measured value.

The iodine adsorption amount (IA) is preferably 60 to 120 mg / g, and more preferably 70 to 100 mg / g. Within such a range, the low heat buildup can be improved by optimizing the surface area.
The iodine adsorption can be measured by the method according to JIS K 6217-1 (2008) [Carbon black for rubber-Basic characteristics-Part 1: Determination of iodine adsorption (titration method)]. it can.

Further, carbon black is preferably DBP (dibutyl phthalate) absorption amount is 50 to 100 cm ^3/100 g.
DBP is absorption of 50 to 100 cm ^3/100 g, by using the low structure carbon black, it is possible to achieve both adequate flexibility and reinforcement of the rubber composition, to obtain a better resistance to crack propagation resistance be able to. DBP absorption of carbon black ^is more preferably more preferably 90cm 3/100 g or ^less, or less 80 cm 3/100 g.
Further, the DBP absorption amount of carbon black represents the amount of DBP (dibutyl phthalate) absorbed by 100 g of carbon black, and can be measured by a method in accordance with JIS K 6217-4 (2008).

The type of carbon black is not particularly limited as long as N ₂ SA / IA is 1.2 m ² / mg or less, and, for example, any hard carbon produced by an oil furnace method can be used. Among these, from the viewpoint of achieving more excellent low heat buildup and resistance to crack development, it is preferable to use HAF grade carbon black.

  The content of carbon black in the rubber composition is preferably 35 to 45 parts by mass with respect to 100 parts by mass of the rubber component. By setting the content of carbon black to 35 parts by mass or more with respect to 100 parts by mass of the rubber component, high reinforcement and crack propagation resistance can be obtained, and by setting the content to 45 parts by mass or less, low heat generation It is possible to further improve the

[Resin component]
The rubber composition of the present invention contains a resin component containing a resin having an SP value of 10 (cal / cm ³ ) ^1/2 or more.
In the present invention, a resin component refers to a component which is cured together with the resin in addition to a resin having an SP value of 10 (cal / cm ³ ) ^1/2 or more and taken into a resin molecule as a part of the resin Curing agents such as methylene donors).
If the SP value of the resin is less than 10 (cal / cm ³ ) ^1/2, it is easy to be compatible with the rubber component, and thus there is a tendency to inhibit the formation of a network between carbon blacks through the resin. Not excellent in crack propagation resistance. SP values of the resin, from the viewpoint of enhancing the resistance to crack growth resistance of the vulcanized rubber, is preferably 10.3 (cal / cm ^{3) 1/2} or ^{more, 11.0 (cal / cm 3)} 1 / It is more preferably ² or more, still more preferably 12.0 (cal / cm ³ ) ^1/2 or more, and still more preferably 12.5 (cal / cm ³ ) ^1/2 or more. Resins with SP values greater than 16 (cal / cm ³ ) ^1/2 are difficult to obtain.
The SP value of the resin can be calculated according to the Flory-Huggins equation.

The resin is not particularly limited as long as it has an SP value of 10 (cal / cm ³ ) ^1/2 or more, and, for example, terpene resin, phenol resin, coumarone / indene resin, xylene resin, rosin resin, aromatic resin At least one resin selected from hydrocarbon resins, aliphatic hydrocarbon resins, and alicyclic hydrocarbon resins may be mentioned.
A terpene resin is a resin which has a terpene polymer or its modified substance as a main component, and trade name "YS resin PX" made by Yashara Chemical Co., Ltd. "YS resin PXN", "YS resin TO" and "YS resin TR" “Picolight” series manufactured by Hercules Inc., and the like.
The phenol resin is preferably a novolak-based thermoplastic phenol resin, such as Sumitomo Bakelite Co., Ltd., trade name “Sumilite Resin PR” series, Arakawa Chemical Co., Ltd. trade name “Tamanor 501” and the like.
The coumarone-indene resin is obtained by polymerizing coumarone, indene, styrene or the like in coal tar, and examples thereof include the coumarone resin series of Kobe Oil Chemical Industry Co., Ltd. (made).
The xylene resin is a resin obtained by condensing xylene and formaldehyde or a modified product thereof, and examples thereof include a trade name “Lignol” series manufactured by Lignite Co., Ltd.
Examples of rosin resins include pentaerythritol ester of rosin, glycerol ester of rosin, polymerized rosin, hydrogenated rosin and the like.
The aromatic hydrocarbon resin is a petroleum resin produced from a C9 fraction, and examples thereof include “Niseki Neopolymer” series manufactured by JX Nippon Oil & Energy Corporation and the like.
The aliphatic hydrocarbon resin is a petroleum resin produced from a C5 fraction, and examples thereof include a trade name “Escollets” series manufactured by Exxon Mobil Co., a trade name “Quinton 100” series manufactured by Nippon Zeon Co., Ltd., and the like.
Examples of alicyclic hydrocarbon resins include petroleum resins produced mainly from high purity cyclopentadiene extracted from a C5 fraction, and C5 resins have an SP value of 10 (cal / cm ³ ). ^Many are less than ^1/2 . Therefore, in order to make the SP value of the resin 10 or more (cal / cm ³ ) ^1/2 , a dicyclopentadiene-based resin (DCPD produced by using dicyclopentadiene dimerized cyclopentadiene as a main raw material) It is preferable to use a resin).
Preferable examples of the dicyclopentadiene resin include Quinton 1000 series (Quinton 1105, Quinton 1325, Quinton 1340) manufactured by Zeon Corporation.
Among the above, a resin having an SP value of 10 (cal / cm ³ ) ^1/2 or more is preferably a dicyclopentadiene resin (DCPD resin) and a phenol resin, and more preferably a phenol resin.

The content of the resin having an SP value of 10 (cal / cm ³ ) ^1/2 or more in the rubber composition is preferably 2 to 10 parts by mass with respect to 100 parts by mass of the rubber component, and 3 to 7 More preferably, it is part by mass. The crack propagation resistance can be further improved by setting the content of the resin having an SP value of 10 (cal / cm ³ ) ^1/2 or more to 2 parts by mass or more with respect to 100 parts by mass of the rubber component. By setting the amount to 10 parts by mass or less, deterioration of low heat buildup can be suppressed.

(Phenol resin)
The phenolic resin will be described in more detail.
The rubber composition contains a phenol resin together with a methylene donor to be described later, thereby improving the 50% modulus value (M50) of the rubber composition and maintaining the excellent low heat buildup, while reinforcing the rubber composition. Improve the crack resistance and achieve excellent crack propagation resistance.
The phenol resin is not particularly limited, and can be appropriately selected according to the required performance. Examples thereof include those produced by condensation reaction of phenols such as phenol, cresol, resorcin, tert-butylphenol or mixtures thereof with formaldehyde in the presence of an acid catalyst such as hydrochloric acid or oxalic acid. Further, as the phenol resin, a modified resin can be used, for example, it can be modified with an oil such as rosin oil, tall oil, cashew oil, linoleic acid, oleic acid, linolenic acid and the like.
A phenol resin can also be included individually by 1 type, and can also be mixed and contained in multiple types.

(Methylene donor)
The rubber composition of the present invention preferably contains a methylene donor as a resin component together with a phenolic resin.
By containing a melamine donor, it functions as a curing agent for a phenol resin, improves the 50% modulus value (M50) of the rubber composition, and improves the reinforcement of the rubber composition while maintaining excellent low heat buildup. It is easy to set the ratio of M200 to M50 to 5.0 or less (M200 / M50 ≦ 5.0).
Furthermore, from the viewpoint of further improving the low heat buildup and crack propagation resistance of the vulcanized rubber, the resin component preferably comprises a phenol resin and a methylene donor.

The type of methylene donor is not particularly limited, and can be appropriately selected according to the required performance. For example, hexamethylenetetramine, hexamethoxymethylolmelamine, pentamethoxymethylolmelamine, hexamethoxymethylmelamine, pentamethoxymethylmelamine, hexaethoxymethylmelamine, hexakis- (methoxymethyl) melamine, N, N ', N "-trimethyl-N , N ′, N ′ ′-trimethylolmelamine, N, N ′, N ′ ′-trimethylolmelamine, N-methylolmelamine, N, N ′-(methoxymethyl) melamine, N, N ′, N ′ ′-tributyl-N And N ′, N ′ ′-trimethylolmelamine, paraformaldehyde, etc. Among these, the methylene donor is selected from the group consisting of hexamethylenetetramine, hexamethoxymethylmelamine, hexamethoxymethylolmelamine and paraformaldehyde Is preferably at least one.
These methylene donors may be used alone or in combination of two or more.

  In addition, the ratio of the content of the phenol resin to the content of the methylene donor is 0.6 to 7 from the viewpoint of achieving both the low heat buildup and the crack propagation resistance of the vulcanized rubber at a still higher level. Is preferable, and 1 to 5 is more preferable. When the ratio of the content of the phenol resin to the content of the methylene donor is 0.6 or more, the M50 of the vulcanized rubber can be more easily improved, and the crack propagation resistance can be further improved. Further, when the ratio is 7 or less, the low heat buildup of the vulcanized rubber is excellent.

[Other ingredients]
The rubber composition of the present invention can contain other components in addition to the above-described rubber component, carbon black, and resin component as long as the effects of the present invention are not impaired.
As other components, for example, fillers other than the carbon black, antioxidants, crosslinking accelerators, crosslinking agents, crosslinking accelerators, silane coupling agents, stearic acid, antiozonants, surfactants and the like Additives commonly used in the rubber industry can be included as appropriate.

(Filling material)
Examples of the filler include silica, other inorganic fillers and the like.
Among them, it is preferable to contain silica as a filler. Since the rubber composition contains silica, the vulcanized rubber can easily generate heat in a high strain region and can improve the crack resistance, so that a more excellent low heat generation and crack propagation resistance can be obtained. Be

[silica]
Examples of the silica include wet silica, colloidal silica, calcium silicate, and aluminum silicate.
Among the above, silica is preferably wet silica, and more preferably precipitated silica. These silicas have high dispersibility, and can further improve the low heat buildup and crack propagation resistance of the vulcanized rubber obtained from the rubber composition. In addition, with precipitated silica, the reaction is allowed to proceed in a relatively high temperature, neutral to alkaline pH range at the initial stage of production to grow primary silica particles, and then control is made to the acidic side to aggregate primary particles. It is the silica obtained as a result of

The silica preferably has a BET surface area of 100 to 250 m ² / g, and preferably 160 to 220, from the viewpoint of the rubber reinforcing property and the dispersibility in the rubber component. Moreover, it is preferable that it is 80-230 m < ² > / g, and, as for a cetyl trimethyl ammonium bromide specific surface area (CTAB specific surface area), it is more preferable that it is 130-180 m < ² > / g.

  Although the content of silica in the rubber composition is not particularly limited, it is 1 to 15 parts by mass with respect to 100 parts by mass of the rubber component from the viewpoint of realizing excellent low heat buildup of the vulcanized rubber. Is preferable, and 3 to 10 parts by mass is more preferable.

In addition, as an inorganic filler, the inorganic compound represented by following formula (I) can also be used, for example.
nM · xSiO _Y · zH ₂ O (I)
Wherein M is a metal selected from the group consisting of aluminum, magnesium, titanium, calcium and zirconium, oxides or hydroxides of these metals, and hydrates thereof, and carbonates of these metals N, x, y and z are each an integer of 1 to 5, an integer of 0 to 10, an integer of 2 to 5 and an integer of 0 to 10.)

As the inorganic compound of the formula (I), alumina (Al ₂ O ₃ ) such as γ-alumina or α-alumina; alumina monohydrate such as boehmite or diaspore (Al ₂ O ₃ · H ₂ O); gibbsite, Aluminum hydroxide [Al (OH) ₃ ] such as bayerite; aluminum carbonate [Al ₂ (CO ₃ ) ₃ ], magnesium hydroxide [Mg (OH) ₂ ], magnesium oxide (MgO), magnesium carbonate (MgCO ₃ ) , Talc (3MgO · 4SiO ₂ · H ₂ O), attapulgite (5MgO · 8SiO ₂ · 9H ₂ O), titanium white (TiO ₂ ), titanium black (TiO _{2 n-1} ), calcium oxide (CaO), calcium hydroxide [Ca _(OH) 2], magnesium aluminum oxide _{(MgO · Al 2 O 3)} , clay _{(Al 2} O 3 · 2SiO ), Kaolin _{(Al 2 O 3 · 2SiO 2} · 2H 2 O), pyrophyllite _{(Al 2 O 3 · 4SiO 2} · H 2 O), bentonite _{(Al 2 O 3 · 4SiO 2} · 2H 2 O), Kay Magnesium silicate (Mg ₂ SiO ₄ , MgSiO ₃ etc.), aluminum calcium silicate (Al ₂ O ₃ · CaO ₂ SiO ₂ etc.), magnesium calcium silicate (CaMgSiO ₄ ), calcium carbonate (CaCO ₃ ), zirconium oxide (ZrO 2 ₂ ), zirconium hydroxide [ZrO (OH) ₂ · n H ₂ O], zirconium carbonate [Zr (CO ₃ ) ₂ ], crystals containing hydrogen, alkali metal or alkaline earth metal that corrects electric charge like various zeolites Aluminosilicates and the like can be mentioned.

  As an antiaging agent, a well-known thing can be used and it does not restrict | limit in particular. For example, a phenolic antioxidant, an imidazole antioxidant, an amine antioxidant etc. can be mentioned. These antiaging agents can be used alone or in combination of two or more.

  As a crosslinking accelerator, a well-known thing can be used and it does not restrict | limit in particular. For example, thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole and dibenzothiazyl disulfide; N-cyclohexyl-2-benzothiazylsulfenamide, N-t-butyl-2-benzothiazylsulfenamide and the like Sulfenamide-based vulcanization accelerator; guanidine-based vulcanization accelerator such as diphenylguanidine; tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetradodecylthiuram disulfide, tetraoctylthiuram disulfide, tetrabenzylthiuram disulfide, Thiuram-based vulcanization accelerators such as pentamethylenethiuram tetrasulfide; dithiocarbamate-based vulcanization accelerators such as zinc dimethyldithiocarbamate; zinc dialkyldithiophosphates etc. .

The crosslinking agent is also not particularly limited. For example, sulfur, bismaleimide compounds and the like can be mentioned.
Types of bismaleimide compounds include, for example, N, N'-o-phenylenebismaleimide, N, N'-m-phenylenebismaleimide, N, N'-p-phenylenebismaleimide, N, N '-(4, 4′-diphenylmethane) bismaleimide, 2,2-bis- [4- (4-maleimidophenoxy) phenyl] propane, bis (3-ethyl-5-methyl-4-maleimidophenyl) methane and the like can be exemplified. . In the present invention, N, N'-m-phenylenebismaleimide, N, N '-(4,4'-diphenylmethane) bismaleimide and the like can be suitably used.

Examples of the crosslinking accelerator include zinc white (ZnO) and fatty acids.
The fatty acid may be any saturated or unsaturated, linear or branched fatty acid, and the carbon number of the fatty acid is not particularly limited, and is, for example, a fatty acid having 1 to 30 carbon atoms, preferably 15 to 30 carbon atoms, More specifically, naphthenic acids such as cyclohexane acid (cyclohexanecarboxylic acid), alkyl cyclopentane having a side chain; hexanoic acid, octanoic acid, decanoic acid (including branched carboxylic acids such as neodecanoic acid), dodecanoic acid, tetradecane Saturated fatty acids such as acids, hexadecanoic acid and octadecanoic acid (stearic acid); unsaturated fatty acids such as methacrylic acid, oleic acid, linoleic acid and linolenic acid; resin acids such as rosin, tall oil acid and abietic acid. These may be used singly or in combination of two or more. In the present invention, zinc flower and stearic acid can be suitably used.

  When silica is contained as a filler, it may further contain a silane coupling agent. This is because the effects of reinforcing properties and low heat buildup of the vulcanized rubber with silica can be further improved. In addition, a well-known thing can be used suitably for a silane coupling agent. The preferable content of the silane coupling agent varies depending on the type of the silane coupling agent and the like, but is preferably in the range of 2 to 25 parts by mass, and preferably 2 to 20 parts by mass with respect to 100 parts by mass of silica. Is more preferably in the range of 5 to 18 parts by mass. When the content is 2 parts by mass or more, the effect as a coupling agent is easily exhibited sufficiently, and when the content is 25 parts by mass or less, gelation of the rubber component is hardly caused.

<Method of producing rubber composition>
Next, a method for producing the rubber composition of the present invention will be described.
The method for producing the rubber composition of the present invention is not particularly limited, and each component (rubber component, carbon black, resin component and other components) constituting the rubber composition is compounded and kneaded. You can get it.

  In the method of producing the rubber composition of the present invention, the above-described components may be simultaneously kneaded, or any of the components may be previously kneaded, and then the remaining components may be kneaded. About these conditions, it can change suitably according to the performance for which a rubber composition is required.

  For example, it is preferable to blend and knead the rubber component and carbon black prior to blending of the phenol resin, from the viewpoint of achieving more excellent low heat buildup and other crack developability of the vulcanized rubber. Since the phenolic resin has a strong interaction with carbon black, the reaction of the rubber component with the carbon black can be facilitated by blending the phenolic resin after kneading the rubber component and the carbon black, and the carbon black in the rubber component Easy to disperse. As a result, the reinforcing property of the vulcanized rubber is improved, and the low heat buildup and the resistance to cracking can be further improved.

<Vulcanized rubber>
The vulcanized rubber of the present invention comprises the rubber composition of the present invention. A vulcanized rubber is obtained by vulcanizing the rubber composition of the present invention according to a conventional method.
The rubber composition of the present invention has a ratio of 200% modulus value (M200) to 50% modulus value (M50) after vulcanization is 5.0 or less (M200 / M50 ≦ 5.0). That is, the vulcanized rubber obtained by vulcanizing the rubber composition of the present invention has M200 / M50 of 5.0 or less.
M200 / M50 can be adjusted by the type and content of carbon black, etc. When a phenolic resin and a methylene donor are contained as a resin component, the type of phenolic resin and methylene donor, the respective amounts, the ratio, etc. Can be adjusted by the adjustment of
From the viewpoint of achieving excellent low heat buildup and resistance to crack development of the vulcanized rubber, M200 / M50 is preferably 4.8 or less, more preferably 4.5 or less. M200 / M50 of the vulcanized rubber is usually difficult to be less than 3.5, and is 3.5 or more.
The 50% modulus is the tensile stress at 50% elongation of the vulcanized rubber, and the 200% modulus is the tensile stress at 200% elongation of the vulcanized rubber. These values can be measured in accordance with JIS K 6251 (2010).

  The specific numerical range of M50 and M200 is not particularly limited, but from the viewpoint of achieving low heat buildup and resistance to crack propagation at higher levels, M50 is 1.6 or more and M200 is 10.5 or less It is preferable that M50 is 1.8 or more and M200 is 9.0 or less.

The vulcanized rubber of the present invention is a ratio of loss tangent (tan δ _100% ) at 100% strain at 24 ° C. to loss tangent (tan δ _1% ) at 1% strain at 24 ° C (tan δ _100% / tan δ _1% ) Is preferably 0.6 or more.
While heat generation with high strain produces the effect of releasing the development of cracks in the vulcanized rubber as heat, the low heat generation with low strain makes the low heat build-up and crack development resistance of the vulcanized rubber more compatible can do. Therefore, when such a vulcanized rubber is applied to a tire, the fuel efficiency as a tire is excellent.
The tan δ _100% / tan δ _1% can be adjusted by changing the type and content of the resin component.
The tan δ _100% / tan δ _1% is more preferably 0.65 or more, and more preferably 0.70 or more, from the viewpoint of achieving a high degree of compatibility between the low heat buildup and the crack propagation resistance of the vulcanized rubber. It is more preferable that it is 0.75 or more, and it is more preferable that it is 0.90 or less.

<Belt coating rubber>
The belt-coated rubber of the present invention comprises the above-mentioned vulcanized rubber of the present invention. By using the vulcanized rubber of the present invention as a belt coating rubber of a tire, the obtained belt coating rubber can have excellent low heat buildup and resistance to crack propagation.

<Between rubber>
The rubber used in the present invention is the vulcanized rubber of the present invention described above.
The intermediate rubber is a rubber of an intermediate layer interposed between the layers, and can be used specifically as, for example, a ply insert rubber inserted between a ply of a tire and a belt.
By using the vulcanized rubber of the present invention as the rubber during the present invention, the obtained rubber can have excellent low heat buildup and resistance to crack propagation.

<Tire>
The tire of the present invention uses the above-mentioned vulcanized rubber of the present invention. By using the vulcanized rubber of the present invention as a tire material, the obtained tire can have excellent low loss and crack propagation resistance.
Specifically, in the tire of the present invention, the vulcanized rubber of the present invention is applied to any member, but among the members for a tire, it is preferable to apply to the belt-coated rubber as described above.
A conventional method can be used as a method of manufacturing a tire. For example, on a drum for forming a tire, members used for producing a normal tire such as a carcass layer, a belt layer, a tread layer and the like comprising the rubber composition and cord of the present invention are sequentially laminated, and the drum is removed to obtain a green tire. Then, the desired green tire (for example, a pneumatic tire) can be manufactured by heating and vulcanizing this green tire according to a conventional method. Examples of the gas to be filled in the tire include normal or air of which oxygen partial pressure is changed, or an inert gas such as nitrogen.

  EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples.

<Examples 1 to 10, Comparative Examples 1 to 8>
According to the composition shown in Tables 1 and 2, a rubber composition sample was prepared by blending and kneading in a usual manner. In addition, about kneading | mixing of each component, it carried out by the Banbury mixer of capacity 3.0L. In Example 7, the phenol resin, the rubber component and the carbon black were simultaneously kneaded. On the other hand, as to the example in which other phenolic resin was blended, the rubber component and carbon black were kneaded prior to the kneading with the resin.

<Physical property measurement>
The tensile stress and the viscoelasticity of the vulcanized rubber of each sample of the prepared rubber compositions of the Examples and Comparative Examples were measured as follows.

(1) Tensile stress The rubber composition of each sample was vulcanized at 145 ° C. for 40 minutes to obtain a vulcanized rubber. With respect to the obtained vulcanized rubber, 50% modulus value (M50) and 200% modulus value (M200) were measured by a method in accordance with JIS K 6251 (2010).
Also, from the obtained M50 and M200, the ratio (M200 / M50) of the 200% modulus value (M200) to the 50% modulus value (M50) was calculated.
The obtained results are shown in Tables 1 and 2.

(2) Viscoelasticity The rubber composition of each sample was vulcanized at 145 ° C. for 40 minutes to obtain a vulcanized rubber. With respect to the obtained vulcanized rubber, using a spectrometer (manufactured by Ueshima Seisakusho Co., Ltd.), at a temperature of 24 ° C. and a frequency of 52 Hz, a loss tangent at low strain (tan δ _1% ) and strain with _1% strain are The loss tangent (tan δ _100% ) at high strain with _100% was measured.
From the obtained results, tan δ _100% / tan δ _1% was calculated and is shown in Tables 1 and 2.

<Evaluation of rubber composition>
The following evaluation was performed about each sample of the rubber composition of the prepared Example and comparative example.

(1) Low heat buildup The rubber composition of each sample was vulcanized at 145 ° C. for 40 minutes to obtain a vulcanized rubber. With respect to the obtained vulcanized rubber, loss tangent (tan δ) was measured using a spectrometer (manufactured by Ueshima Seisakusho Co., Ltd.) under the conditions of a temperature of 24 ° C., a strain of 1%, and a frequency of 52 Hz.
About evaluation, it shows with an index when tandelta of a sample of comparative example 1 is set to 100, and it is excellent in low exothermic nature, so that an index value is small. The evaluation results are shown in Tables 1 and 2.

(2) Crack resistance (crack growth resistance)
The rubber composition of each sample was vulcanized at 145 ° C. for 40 minutes to obtain a vulcanized rubber. A sheet of 2 mm × 50 mm × 6 mm was produced from the obtained vulcanized rubber, and a minute hole was made in the center to make an initial crack. Thereafter, stress was repeatedly applied to the sheet in the long side direction under the conditions of 2.0 MPa, a frequency of 6 Hz, and an atmosphere temperature of 80 ° C. And after measuring the number of repetition until a test piece fractures after applying stress repeatedly for every sample, the common logarithm of the number of repetitions was computed. In addition, the measurement test to a fracture | rupture was implemented 4 times for every sample, the common logarithm was calculated, and those average was made into the average common logarithm.
About evaluation, it shows as an index when the average common logarithm of the comparative example 1 is set to 100, and it shows that it is excellent in crack extension resistance, so that the average common logarithm of a sample is large. The evaluation results are shown in Tables 1 and 2.

1. Rubber component (1) NR: Natural rubber, TSR20
(2) BR: Butadiene rubber, manufactured by JSR Corporation, trade name "BR01"
(3) SBR: styrene butadiene rubber, manufactured by Asahi Kasei Chemicals Corporation, trade name "TUFDENE 3835"

2. Carbon Black (1) Carbon Black 1:
HAF class carbon black, manufactured by Tokai Carbon Co., Ltd., trade name “N326”, nitrogen adsorption specific surface area (N ₂ SA) = 78 m ² / g, iodine adsorption amount (IA) = 82 mg / g, N ₂ SA / IA = 0.95 m ² / mg
(2) Carbon black 2:
ISAF grade carbon black, manufactured by Tokai Carbon Co., Ltd., trade name "Seat 7HM", nitrogen adsorption specific surface area (N ₂ SA) = 126 m ² / g, iodine adsorption amount (IA) = 120 mg / g, N ₂ SA / IA = 1.05 m ² / mg
(3) Carbon black 3:
HAF class carbon black, manufactured by Mitsubishi Chemical Corporation, trade name "Large Black LH", nitrogen adsorption specific surface area (N ₂ SA) = 88 m ² / g, iodine adsorption amount (IA) = 75 mg / g, N ₂ SA /IA=1.17 m ² / mg
(4) Carbon black 4:
HAF class carbon black, manufactured by Tokai Carbon Co., Ltd., trade name “Seat NH”, nitrogen adsorption specific surface area (N ₂ SA) = 74 m ² / g, iodine adsorption amount (IA) = 70 mg / g, N ₂ SA / IA = 1.05 m ² / mg
(5) Carbon black 101:
GPF grade carbon black, manufactured by Asahi Carbon Co., Ltd., trade name “Asahi NPG”, nitrogen adsorption specific surface area (N ₂ SA) = 28 m ² / g, iodine adsorption amount (IA) = 21 mg / g, N ₂ SA / IA = 1.33 m ² / mg

3. Resin component (1) C5-based resin: manufactured by Mitsui Petrochemical Industries, Ltd., trade name "HI-REZ G-100X"
(2) DCPD resin: manufactured by Nippon Zeon Co., Ltd., trade name "Quinton 1105"
(3) Modified phenolic resin: Thor modified phenolic resin, manufactured by Sumitomo Bakelite Co., Ltd., trade name "Sumilite resin PR-51587"
(4) Phenolic resin: Novolak type phenolic resin, manufactured by Sumitomo Bakelite Co., Ltd., trade name "Sumilight resin PR-50235"
(5) Hexamethoxymethylmelamine: manufactured by ALLNEX, trade name "CYREZ 964"

4. Various components (1) Silica: Tosoh Silica Corporation, trade name "Nip seal AQ", nitrogen adsorption specific surface area = 210 m ² / g, BET surface area = 205 m ² / g
(2) Zinc oxide: manufactured by Hakusui Tech Co., Ltd., trade name "No. 3 zinc flower"
(3) Anti-aging agent A: made by Ouchi Emerging Chemical Industry Co., Ltd., trade name "NOCRACK NS-6", 2,2'-methylenebis (4-methyl-6-tert-butylphenol)
(4) Anti-aging agent B: product of Ouchi Shinko Chemical Co., Ltd., trade name "NOCRAC 6C", N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine (5) sulfur: Tsurumi Chemical Co., Ltd. product name, "powder sulfur"
(6) Vulcanization accelerator: made by Ouchi Emerging Chemical Industry Co., Ltd., trade name "Noxceler DZ", N, N-dicyclohexyl-2-benzothiazolylsulfenamide (7) Cobalt salt: manufactured by OMG, product Name "MANOBOND C", a complex salt in which a part of the organic acid in the cobalt salt of an organic acid is replaced with boric acid, cobalt content: 22.0% by mass
(8) Bismaleimide: manufactured by Daiwa Kasei Kogyo Co., Ltd., trade name "BMI-RB"

The SP values [(cal / cm ³ ) ^1/2 ] of rubber components and resins in the table were calculated according to the Flory-Huggins equation.

  From the results of Tables 1 and 2, it was found that the samples of the examples exhibited well-balanced and excellent values for both the low heat buildup and the crack propagation resistance, as compared with the samples of the comparative examples. By using the rubber composition of these examples, a belt coating rubber and an intermediate rubber capable of achieving both low heat build-up and crack growth resistance at a high level can be obtained, and also low loss and crack growth resistance. It is believed that a tire can be obtained that is compatible with high levels.

  According to the present invention, a rubber composition capable of producing a vulcanized rubber capable of achieving both low heat buildup and resistance to crack development at a high level, and achieves both low heat buildup and resistance to crack development at a high level It is possible to provide vulcanized rubber, belt coated rubber, and rubber between. In addition, it is possible to provide a tire capable of achieving both low loss and high crack propagation resistance at a high level.

Claims (12)

Rubber component,
A carbon black having a ratio of nitrogen adsorption specific surface area (N ₂ SA) m ² / g to iodine adsorption amount (IA) mg / g (N ₂ SA / IA) of 1.2 m ² / mg or less,
And a resin component containing a resin having an SP value of 10 (cal / cm ³ ) ^1/2 or more,
The rubber composition whose ratio of 200% modulus value (M200) with respect to 50% modulus value (M50) after vulcanization is 5.0 or less (M200 / M50 ≦ 5.0).   The rubber composition according to claim 1, wherein the resin component comprises a phenol resin and a methylene donor.   The rubber composition according to claim 1 or 2, wherein the content of the carbon black is 35 to 45 parts by mass with respect to 100 parts by mass of the rubber component.   The rubber composition according to any one of claims 1 to 3, further comprising silica.   The rubber composition according to any one of claims 2 to 4, wherein the methylene donor is at least one selected from the group consisting of hexamethylenetetramine, hexamethoxymethylmelamine, hexamethoxymethylolmelamine and paraformaldehyde. The content of the resin having an SP value of 10 (cal / cm ³ ) ^1/2 or more is 2 to 10 parts by mass with respect to 100 parts by mass of the rubber component. The rubber composition as described in.   The rubber composition according to any one of claims 2 to 6, wherein the ratio of the content of the phenol resin to the content of the methylene donor is 0.6 to 7.   Vulcanized rubber using the rubber composition according to any one of claims 1 to 7. The ratio (tan δ _100% / tan δ _1% ) of the loss tangent (tan δ _100% ) at 100% strain to 24 ° C to the loss tangent (tan δ _1% ) at 1% strain at 24 ° C. is 0.6 or more The vulcanized rubber according to item 8.   A belt coating rubber using the vulcanized rubber according to claim 8 or 9.   A rubber during use of the vulcanized rubber according to claim 8 or 9.   A tire using the vulcanized rubber according to claim 8 or 9.