JP2016166309A - Rubber composition and pneumatic tire prepared therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition that has excellent wear resistance while maintaining excellent low heat generation, and a pneumatic tire prepared therewith.SOLUTION: A rubber composition comprises a diene rubber (A), and an acid-modified polyolefin derivative (B) obtained by making a reaction to occur between an acid-modified polyolefin (b1) and a compound having an amino group (b2) previously, where a content of the acid-modified polyolefin derivative (B) is 1-40 pts.mass relative to the diene rubber (A) 100 pts.mass.SELECTED DRAWING: None

Description

  The present invention relates to a rubber composition and a pneumatic tire using the same.

Conventionally, as a rubber composition constituting a tire, a rubber hose, an industrial belt, an anti-vibration rubber, a fender, etc., a blend of an olefin resin such as propylene / ethylene copolymer with a diene rubber has been proposed. .
For example, Patent Document 1 describes “a rubber composition comprising 1 to 50 parts by weight of a modified polymer obtained by modifying a polyolefin resin with an unsaturated carboxylic acid with respect to 100 parts by weight of a diene rubber”. ([Claim 1]).

JP-A-10-87900

By the way, in recent years, from the viewpoint of protecting the global environment, consideration is also required for pneumatic tires, and the performance of improving fuel consumption is desired.
In order to improve fuel economy, it is only necessary to produce pneumatic tires using a rubber composition that can suppress heat generation during driving. Especially, tire treads that contact the road surface during driving and sidewalls that undergo large repeated deformation during driving. It is considered that the fuel consumption can be improved by reducing the heat generation.
When the present inventors examined the rubber composition for tires described in patent document 1, this rubber composition for tires was blended with a modified polymer obtained by modifying a polyolefin resin with an unsaturated carboxylic acid. Although it is excellent in reducing heat generation, it has been found that further improvement in wear resistance is necessary.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a rubber composition having good wear resistance while maintaining excellent heat generation and a pneumatic tire using the same.

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention obtained, in the rubber composition described in Patent Document 1, a polyolefin modified with an unsaturated carboxylic acid was reacted in advance with, for example, an amine derivative or the like. It was found that by adding a predetermined amount of the acid-modified polyolefin derivative to the diene rubber, the wear resistance was improved while maintaining excellent low heat generation, and the present invention was completed.
That is, the present inventors have found that the above problem can be solved by the following configuration.

[1] A diene rubber (A), an acid-modified polyolefin derivative (B) obtained by reacting an acid-modified polyolefin (b1) and a compound (b2) having an amino group in advance,
The rubber composition whose content of the acid-modified polyolefin derivative (B) is 1 to 40 parts by mass with respect to 100 parts by mass of the diene rubber (A).
[2] The rubber composition according to [1], wherein the amino group-containing compound (b2) is a diamine compound.
[3] The acid-modified polyolefin derivative (B) is converted into the acid-modified polyolefin (b1) from the acid-modified polyolefin (b1) and the compound (b2) having an amino group by a single-screw extruder or a twin-screw kneading extruder. The rubber composition according to [1] or [2], which is obtained by reacting by melting and kneading at a melting point or higher.
[4] The acid-modified polyolefin (b1) according to any one of [1] to [3], wherein the acid-modified polyolefin (b1) is a polyolefin having at least one repeating unit selected from the group consisting of ethylene and α-olefin. Rubber composition.
[5] The rubber composition according to [4], wherein the α-olefin is propylene, 1-butene or 1-octene.
[6] The rubber composition according to any one of [1] to [5], wherein the acid-modified polyolefin (b1) is a polyolefin modified with maleic anhydride.
[7] A pneumatic tire using the rubber composition according to any one of [1] to [6] as a constituent member.
[8] The pneumatic tire according to [7], wherein the constituent member is a tire tread.

  According to the present invention, it is possible to provide a rubber composition having good wear resistance while maintaining excellent heat generation reduction and a pneumatic tire using the rubber composition.

It is a typical fragmentary sectional view of the tire showing an example of the embodiment of the pneumatic tire of the present invention.

[Rubber composition]
The rubber composition of the present invention contains a diene rubber (A), an acid-modified polyolefin derivative (B) obtained by reacting an acid-modified polyolefin (b1) and a compound (b2) having an amino group in advance. It is a rubber composition.
Moreover, content of the said acid-modified polyolefin derivative (B) is 1-40 mass parts with respect to 100 mass parts of said diene rubbers (A).

In the present invention, a predetermined amount of the acid-modified polyolefin derivative (B) obtained by reacting the acid-modified polyolefin (b1) and the amino group-containing compound (b2) in advance with the diene rubber (A). As a result, it is possible to improve the wear resistance while maintaining excellent low heat generation.
This is not clear in detail, but is estimated to be as follows.
That is, silica or the like optionally added by reacting an acid-modified group (for example, maleic anhydride group) of the acid-modified polyolefin (b1) with an amino group of the compound (b2) to generate an amide bond It is considered that the affinity with the filler is increased, whereby the dispersibility of the filler such as silica can be improved, and excellent low heat generation can be maintained. At the same time, in the acid-modified polyolefin derivative (B), the amide groups generated by the reaction between the acid-modified polyolefin (b1) and the amino group-containing compound (b2) are aggregated due to electrical interaction or the like to be dense. By forming the network, it is considered that the mechanical properties of the acid-modified polyolefin derivative (B) are improved and the wear resistance of the rubber composition containing the acid-modified polyolefin derivative (B) is improved.
As shown in a comparative example described later, this is the case where the compound (b2) having an amino group is not used (Comparative Example 2), and the acid-modified polyolefin (b1) and the compound (b2) having an amino group are reacted in advance. It can also be estimated from the fact that when these are melt kneaded simultaneously with the diene rubber (A) (Comparative Example 3), the amount of wear cannot be reduced.
Below, each component which the rubber composition of this invention contains is demonstrated in detail.

[Diene rubber (A)]
The diene rubber (A) contained in the rubber composition of the present invention is not particularly limited as long as it has a double bond in the main chain. Specific examples thereof include natural rubber (NR), isoprene rubber (IR ), Butadiene rubber (BR), aromatic vinyl-conjugated diene copolymer rubber, chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), ethylene-propylene-diene copolymer rubber (EPDM), styrene-isoprene rubber, isoprene -Butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, etc. are mentioned, These may be used individually by 1 type and may use 2 or more types together.
Among these, it is preferable to use aromatic vinyl-conjugated diene copolymer rubber, NR, BR from the viewpoint of better wear resistance and excellent workability.

Examples of the aromatic vinyl-conjugated diene copolymer rubber include styrene-butadiene rubber (SBR), styrene-isoprene rubber, styrene-butadiene-isoprene rubber (SBIR), and among them, SBR is preferable. .
The aromatic vinyl-conjugated diene copolymer rubber may have a terminal modified with a hydroxy group, a polyorganosiloxane group, a carbonyl group, an amino group, or the like.
Furthermore, the weight average molecular weight of the aromatic vinyl-conjugated diene copolymer rubber is not particularly limited, but is preferably 100,000 to 2,500,000, and more preferably 300,000 to 2,000,000 from the viewpoint of processability. . In addition, the weight average molecular weight (Mw) of the aromatic vinyl-conjugated diene copolymer rubber shall be measured in terms of standard polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent.

  The aromatic vinyl-conjugated diene copolymer rubber preferably contains 20 to 50% by mass of aromatic vinyl from the viewpoint of better wear resistance and excellent workability. It is more preferable to contain 20-70 mass%.

  When the diene rubber (A) contains at least an aromatic vinyl-conjugated diene copolymer rubber, the amount of the aromatic vinyl-conjugated diene copolymer rubber can further reduce heat generation, and low heat generation and wet grip From the viewpoint of balance of performance, the diene rubber (A) is preferably contained in an amount of 30 to 100% by mass, and more preferably 40 to 90% by mass.

[Acid-modified polyolefin derivative (B)]
The acid-modified polyolefin derivative (B) contained in the rubber composition of the present invention is obtained by reacting an acid-modified polyolefin (b1) and an amino group-containing compound (b2) in advance.
Hereinafter, the acid-modified polyolefin (b1) and the compound (b2) having an amino group constituting the acid-modified polyolefin derivative (B) will be described in detail.

<Acid-modified polyolefin (b1)>
The acid-modified polyolefin (b1) is a modified polymer obtained by modifying a polyolefin with an unsaturated carboxylic acid.
In the present invention, from the viewpoint of better wear resistance and excellent workability, it is preferably a polyolefin having at least one repeating unit selected from the group consisting of ethylene and α-olefin, and the α -Olefin includes propylene, 1-butene or 1-octene. The polyolefin may be a homopolymer (homopolymer) or a copolymer having these repeating units.

(Polyolefin)
As the polyolefin constituting the skeleton of the acid-modified polyolefin (b1), for example,
Homopolymers such as polypropylene, polybutene, polyoctene;
Propylene / ethylene copolymer, propylene / 1-butene copolymer, propylene / 1-hexene copolymer, propylene / 4-methyl-1-pentene copolymer, propylene / 1-octene copolymer, propylene / 1 -Decene copolymer, propylene / 1,4-hexadiene copolymer, propylene / dicyclopentadiene copolymer, propylene / 5-ethylidene-2-norbornene copolymer, propylene / 2,5-norbornadiene copolymer, Propylene / 5-ethylidene-2-norbornene copolymer, 1-octene / ethylene copolymer, 1-butene / ethylene copolymer, 1-butene / propylene copolymer, 1-butene / 1-hexene copolymer 1-butene / 4-methyl-1-pentene copolymer, 1-butene / 1-octene copolymer, 1-butene -Decene copolymer, 1-butene-1,4-hexadiene copolymer, 1-butene-dicyclopentadiene copolymer, 1-butene-5-ethylidene-2-norbornene copolymer, 1-butene-2 Two-component copolymers such as 5-norbornadiene copolymer and 1-butene-5-ethylidene-2-norbornene copolymer;
Ethylene / propylene / 1-butene copolymer, ethylene / propylene / 1-hexene copolymer, ethylene / propylene / 1-octene copolymer, ethylene / propylene / 1-octene copolymer, ethylene / propylene / 1, 4-hexadiene copolymer, ethylene / propylene / 1,4-hexadiene copolymer, ethylene / propylene / dicyclopentadiene copolymer, ethylene / propylene / dicyclopentadiene copolymer, ethylene / propylene / 5-ethylidene- 2-norbornene copolymer, ethylene / propylene / 5-ethylidene-2-norbornene copolymer, ethylene / propylene / 2, 5-norbornadiene copolymer, ethylene / propylene / 2, 5-norbornadiene copolymer, ethylene / propylene Propylene-5-ethylidene-2-no Borene copolymer, ethylene / propylene / 5-ethylidene-2-norbornene copolymer, 1-butene / ethylene / propylene copolymer, 1-butene / ethylene / 1-hexene copolymer, 1-butene / ethylene / 1-octene copolymer, 1-butene / propylene / 1-octene copolymer, 1-butene / ethylene / 1,4-hexadiene copolymer, 1-butene / propylene / 1,4-hexadiene copolymer, 1-butene / ethylene / dicyclopentadiene copolymer, 1-butene / propylene / dicyclopentadiene copolymer, 1-butene / ethylene / 5-ethylidene-2-norbornene copolymer, 1-butene / propylene / 5 -Ethylidene-2-norbornene copolymer, 1-butene-ethylene-2,5-norbornadiene copolymer, 1-butene・ Multi-components such as propylene / 2,5-norbornadiene copolymer, 1-butene / ethylene / 5-ethylidene-2-norbornene copolymer, 1-butene / propylene / 5-ethylidene-2-norbornene copolymer And the like.

  Among these, polypropylene, polybutene, polyoctene, propylene / ethylene copolymer, 1-butene / ethylene copolymer, 1-butene / propylene copolymer, ethylene / propylene / 1-butene copolymer, 1-octene / It is preferable to use an ethylene copolymer.

(Unsaturated carboxylic acid)
On the other hand, examples of the unsaturated carboxylic acid that modifies the above-described polyolefin include maleic acid, fumaric acid, acrylic acid, crotonic acid, methacrylic acid, itaconic acid, or acid anhydrides of these acids. .
Of these, maleic anhydride, maleic acid, and acrylic acid are preferably used, and maleic anhydride is more preferable.

  Although the acid modification amount (mass%) in the acid-modified polyolefin (b1) is not particularly limited, it is usually 0.1 to 10 mass%, preferably 0.2 to 5 mass%.

The acid-modified polyolefin (b1) may be produced by a method that is usually performed, for example, a method in which an unsaturated carboxylic acid is graft-polymerized to the polyolefin under a condition that is usually performed, for example, stirring under heating. Commercial products may also be used.
Examples of commercially available products include maleic anhydride-modified propylene / ethylene copolymers such as Tuffmer MA8510 (manufactured by Mitsui Chemicals) and MP0620 (manufactured by Mitsui Chemicals); And ethylene / 1-butene copolymer; maleic anhydride-modified polypropylene such as Admer QE060 (manufactured by Mitsui Chemicals); and the like.

<Compound (b2) having an amino group>
The compound (b2) having an amino group is preferably a monofunctional or polyfunctional amine compound, more preferably a polyfunctional amine compound, and still more preferably a diamine compound.
Specific examples of the polyfunctional amine compound include 3,3′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfone, and N- (1,3-dimethylbutyl) -N′-phenyl-p-. Examples thereof include phenylenediamine, metaphenylenediamine, and 1,3-bis (3-aminophenoxy) benzene.
Among these, 3,3′-diaminodiphenyl sulfone and 4,4′-diaminodiphenyl sulfone are preferable from the viewpoints of cost and safety.

<Preparation of acid-modified polyolefin derivative (B)>
0.5-10 mass parts is preferable with respect to 100 mass parts of acid-modified polyolefin (b1), and, as for the quantity of the compound (b2) which has an amino group with respect to acid-modified polyolefin (b1), 1-6 mass parts is more preferable. By making the amount of the compound (b2) having an amino group within the above range, it is possible to achieve both excellent low heat generation properties and wear resistance.

For the acid-modified polyolefin derivative (B), the acid-modified polyolefin (b1) and the compound (b2) having an amino group are mixed with a known kneader such as a kneader, a Banbury mixer, a single-screw kneading extruder, or a twin-screw kneading extruder. Although it can prepare by melt-kneading using, it is preferable to carry out using a single-screw kneading extruder or a twin-screw kneading extruder from the height of the productivity. In addition, unless the effect of this invention is inhibited, you may add the arbitrary additive mentioned later previously with the compound (b2) which has an acid-modified polyolefin (b1) and an amino group.
The melt-kneading conditions depend on the acid-modified polyolefin (b1) used, the amino group-containing compound (b2), and the type and blending amount of any additive, but the melt-kneading temperature depends on the acid-modified polyolefin (b1). The temperature is higher than the melting point, preferably 20 ° C. higher than the melting point of the acid-modified polyolefin (b1) (usually 150 ° C. to 200 ° C.). The melt kneading time (residence time) is typically 1 to 10 minutes, preferably 2 to 8 minutes.
The acid-modified polyolefin derivative (B) prepared by the above method is formed into a film shape, a sheet shape, a tube shape, or the like by a usual method from a die attached to a discharge port of a biaxial kneading extruder in a molten state, for example. It can be obtained by extruding or extruding into a strand and pelletizing with a resin pelletizer.

The content of the acid-modified polyolefin derivative (B) in the rubber composition of the present invention is 1 to 40 parts by mass and 3 to 30 parts by mass with respect to 100 parts by mass of the diene rubber (A). More preferably, it is 5-30 mass parts.
By setting the content of the acid-modified polyolefin derivative (B) in the above range, it is possible to improve the wear resistance while maintaining excellent low heat build-up, and to obtain a practically appropriate breaking elongation.

〔silica〕
The rubber composition of the present invention preferably further contains silica. The silica is not particularly limited, and any conventionally known silica that is blended in the rubber composition for uses such as tires can be used.
Specific examples of the silica include fumed silica, calcined silica, precipitated silica, pulverized silica, fused silica, colloidal silica, and the like. These may be used alone or in combination of two or more. You may use together.

The silica preferably has a CTAB adsorption specific surface area of 50 to 300 m ² / g, more preferably 80 to 250 m ² / g, from the viewpoint of suppressing silica aggregation.
Here, the CTAB adsorption specific surface area was determined by measuring the adsorption amount of n-hexadecyltrimethylammonium bromide on the silica surface according to JIS K6217-3: 2001 “Part 3: Determination of specific surface area—CTAB adsorption method”. Value.

  In the present invention, the content of the silica is preferably 5 to 150 parts by mass, more preferably 10 to 120 parts by mass, with respect to 100 parts by mass of the diene rubber (A). More preferably, it is 100 parts by mass.

〔Silane coupling agent〕
When the rubber composition of the present invention contains the other silica described above, the rubber composition preferably contains a silane coupling agent for the purpose of improving the reinforcing performance of the tire.
Specific examples of the silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, Bis (2-triethoxysilylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxy Silane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N- Methylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl Methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, dimethoxymethylsilylpropylbenzothiazole tetrasulfide These may be used, and these may be used alone or in combination of two or more. Moreover, you may use what made these 1 type, or 2 or more types oligomerize beforehand.

  Specific examples of silane coupling agents other than those described above include, for example, γ-mercaptopropyltriethoxysilane, 3- [ethoxybis (3,6,9,12,15-pentaoxaoctacosan-1-yloxy]. ) Silyl] -1-propanethiol and other mercapto silane coupling agents; 3-octanoylthiopropyltriethoxysilane and other thiocarboxylate silane coupling agents; 3-thiocyanate propyltriethoxysilane and other thiocyanate silane cups Ring agents; and the like. These may be used alone or in combination of two or more. Moreover, you may use what made these 1 type, or 2 or more types oligomerize beforehand.

  Of these, bis- (3-triethoxysilylpropyl) tetrasulfide and / or bis- (3-triethoxysilylpropyl) disulfide is preferably used from the viewpoint of reinforcing effect. Specifically, Examples thereof include Si69 [bis- (3-triethoxysilylpropyl) tetrasulfide; manufactured by Evonik Degussa], Si75 [bis- (3-triethoxysilylpropyl) disulfide; manufactured by Evonik Degussa).

The content of the silane coupling agent is preferably 1 part by mass or more and more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the diene rubber (A).
Moreover, it is preferable that it is 0.1-20 mass parts with respect to 100 mass parts of said silicas, and, as for content of the said silane coupling agent, it is more preferable that it is 0.5-15 mass parts.

〔Carbon black〕
The rubber composition of the present invention preferably contains carbon black.
Specific examples of the carbon black include furnace carbon blacks such as SAF, ISAF, HAF, FEF, GPE, and SRF. These may be used alone or in combination of two or more. May be.
Further, the carbon black, from the viewpoint of workability during mixing of the rubber composition is preferably a nitrogen adsorption specific surface area (N ₂ SA) is 10 to 300 m ² / g, with 20 to 200 m ² / g More preferably.
Here, N ₂ SA is a value obtained by measuring the amount of nitrogen adsorbed on the carbon black surface in accordance with JIS K 6217-2: 2001 “Part 2: Determination of specific surface area—nitrogen adsorption method—single point method”. .

  When the carbon black is contained, the content is preferably 1 to 100 parts by mass and more preferably 5 to 80 parts by mass with respect to 100 parts by mass of the diene rubber (A).

[Other ingredients]
In addition to the components described above, the rubber composition of the present invention comprises a filler such as calcium carbonate; a chemical foaming agent such as a hollow polymer; a vulcanizing agent such as sulfur; a sulfenamide-based, guanidine-based, thiazole-based, thiourea-based, and thiuram. Vulcanization accelerators such as zinc oxide, vulcanization accelerators such as zinc oxide and stearic acid; waxes; aroma oils; paraphenylenediamines (for example, N, N'-di-2-naphthyl-p-phenylenediamine, N -1,3-dimethylbutyl-N′-phenyl-p-phenylenediamine, etc.), ketone-amine condensates (eg 2,2,4-trimethyl-1,2-dihydroquinoline, etc.) Various other additives generally used in rubber compositions for tires such as an agent; a plasticizer; and the like can be blended.
As long as the amount of these additives is not contrary to the object of the present invention, a conventional general amount can be used. For example, for 100 parts by mass of the diene rubber (A), 0.5 to 5 parts by mass of sulfur, 0.1 to 5 parts by mass of the vulcanization accelerator, and 0.1 to 10 parts by mass of the vulcanization accelerator aid. Parts, anti-aging agent 0.5-5 parts by mass, wax 1-10 parts by mass, aroma oil 5-30 parts by mass, respectively.

[Method for producing rubber composition]
The method for producing the rubber composition of the present invention is not particularly limited, and examples thereof include a method of kneading the above-described components using a known method and apparatus (for example, a Banbury mixer, a kneader, a roll, etc.). It is done.
The rubber composition of the present invention can be vulcanized or crosslinked under conventionally known vulcanization or crosslinking conditions.

[Pneumatic tire]
The pneumatic tire of the present invention (hereinafter also simply referred to as “the tire of the present invention”) is a pneumatic tire using the above-described rubber composition of the present invention as a constituent (rubber) member.
Here, the constituent member using the rubber composition of the present invention is not particularly limited, and examples thereof include a tire tread portion, a sidewall portion, a bead portion, a belt layer covering, a carcass layer covering, an inner liner, etc. The tire tread portion is preferable.
FIG. 1 shows a schematic partial cross-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, the code | symbol 1 represents a bead part, the code | symbol 2 represents a sidewall part, and the code | symbol 3 represents the tread part comprised from the rubber composition of this invention.
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.
In the tire tread 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.
Further, an inner liner 9 is disposed on the inner surface of the tire in order to prevent air filled in the tire from leaking outside the tire.

For example, when the rubber composition of the present invention is used for a tire tread portion, the tire of the present invention can greatly enjoy the effect of improving wear resistance while maintaining excellent low heat generation.
The tire of the present invention is, for example, at a temperature corresponding to the diene rubber (A) used in the rubber composition of the present invention, the type of vulcanization or crosslinking agent, the type of vulcanization or crosslinking accelerator, and the blending ratio thereof. It can be produced by vulcanization or crosslinking to form a tire tread portion.

  Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.

<Preparation of acid-modified polyolefin derivative B1>
Biaxial kneading extruder (stock) at a ratio of 2 parts by mass of diamine compound 1 (3,3-diaminodiphenylsulfone (manufactured by Mitsui Chemicals Fine)) to 100 parts by mass of acid-modified polyolefin (Tuffmer MH7020, manufactured by Mitsui Chemicals) The product was introduced into the cylinder from the raw material supply port of Nippon Steel Co., Ltd., transported to a kneading zone set at a temperature of 200 ° C. and a residence time of about 6 minutes, and melt-kneaded, and the melt-kneaded material was attached to the discharge port. Extruded into a strand from the die. The obtained strand-shaped extrudate was pelletized with a resin pelletizer to obtain a pellet-shaped acid-modified polyolefin derivative B1. A new peak was observed at 1515 to 1650 cm ⁻¹ by IR measurement (transmission), confirming the formation of an amide bond.

<Preparation of acid-modified polyolefin derivative B2>
Biaxial kneading extruder (stock) at a ratio of 5 parts by mass of diamine compound 2 (4,4-diaminodiphenylsulfone (manufactured by Mitsui Chemicals Fine)) to 100 parts by mass of acid-modified polyolefin (Tuffmer MH7020, manufactured by Mitsui Chemicals) The product was introduced into the cylinder from the raw material supply port of Nippon Steel Co., Ltd., transported to a kneading zone set at a temperature of 200 ° C. and a residence time of about 6 minutes, and melt-kneaded, and the melt-kneaded material was attached to the discharge port. Extruded into a strand from the die. The obtained strand-like extrudate was pelletized with a resin pelletizer to obtain a pellet-like acid-modified polyolefin derivative B2. A new peak was observed at 1515 to 1650 cm ⁻¹ by IR measurement (transmission), confirming the formation of an amide bond.

<Preparation of acid-modified polyolefin derivative B3>
Raw material of twin-screw kneading extruder (manufactured by Nippon Steel Works) at a ratio of 8 parts by weight of stearylamine (Farmin 80, manufactured by Kao Corporation) to 100 parts by weight of acid-modified polyolefin (Tuffmer MH7020, manufactured by Mitsui Chemicals) The mixture was introduced into the cylinder from the supply port, conveyed to a kneading zone set at a temperature of 200 ° C. and a residence time of about 6 minutes, melt-kneaded, and the melt-kneaded product was extruded into a strand from a die attached to the discharge port. The obtained strand-shaped extrudate was pelletized with a resin pelletizer to obtain a pellet-shaped acid-modified polyolefin derivative B3. A new peak was observed at 1515 to 1650 cm ⁻¹ by IR measurement (transmission), confirming the formation of an amide bond.

<Preparation of acid-modified polyolefin derivative B4>
In the preparation of the above-mentioned acid-modified polyolefin derivative B1, diamine compound 1 (3,3-diaminodiphenyl sulfone (manufactured by Mitsui Chemicals Fine))) is 0 for 100 parts by mass of acid-modified polyolefin (Tuffmer MH7020, manufactured by Mitsui Chemicals). An acid-modified polyolefin derivative was prepared by the same method except that the amount was changed to 0.5 parts by mass to obtain a pellet-like acid-modified polyolefin derivative B4. A new peak was observed at 1515 to 1650 cm ⁻¹ by IR measurement (transmission), confirming the formation of an amide bond.

<Examples 1-7 and Comparative Examples 1-7>
The components shown in Table 1 below were blended in the proportions (parts by mass) shown in Table 1 below.
Specifically, the components shown in Table 1 below, excluding sulfur and the vulcanization accelerator, were kneaded for 5 minutes with a 1.7 liter closed mixer and released when the temperature reached 150 ° C. A master batch was obtained.
Next, sulfur and a vulcanization accelerator were kneaded with an open roll in the obtained master batch to obtain a rubber composition.
Next, the obtained rubber composition was vulcanized at 160 ° C. for 20 minutes in a lamborn abrasion mold (diameter 63.5 mm, disk shape 5 mm thick) to produce a vulcanized rubber sheet.

  The following evaluation was performed using the vulcanized rubber sheet produced as described above. The results are shown in Table 1.

<Elongation at break (E _B ): (Indicator of elongation at break)>
A JIS No. 3 dumbbell-shaped test piece was punched out from the vulcanized rubber sheet produced, a tensile test at a tensile speed of 500 mm / min was performed in accordance with JIS K6251: 2010, and elongation at break (E _B ) was measured at 25 ° C. did.
The measurement results were expressed as an index with the value of Comparative Example 1 being 100, and are shown in Table 1 below. It means that it is excellent in elongation at break, so that this index | exponent is large. When the index is 90 or more, a practically appropriate elongation can be obtained.

<Rebound resilience (60 ° C)>
About the produced vulcanized rubber sheet, the resilience at a temperature of 60 ° C. was measured according to JIS K6255: 2013.
The measurement results were expressed as an index with the value of Comparative Example 1 being 100, and are shown in Table 1 below. The larger the index, the better the resilience.

<Tan δ (60 ° C.)>
Using the viscoelastic spectrometer (manufactured by Iwamoto Seisakusho Co., Ltd.), the loss tangent tan δ (60 ° C.) was measured for the prepared vulcanized rubber sheet under the conditions of an elongation deformation strain rate of 10 ± 2%, a frequency of 20 Hz, and a temperature of 60 ° C. It was measured.
The measurement results were expressed as an index with the value of Comparative Example 1 being 100, and are shown in Table 1 below. It means that it is excellent in low exothermic property, so that this index | exponent is small.

<Abrasion resistance>
Each of the prepared rubber compositions was vulcanized at 170 ° C. for 15 minutes in a Lambourn wear mold (disk shape with a diameter of 63.5 mm and a thickness of 5 mm) to produce a vulcanized rubber sheet.
Next, using a Lambourn abrasion tester (manufactured by Iwamoto Seisakusho Co., Ltd.), in accordance with JIS K 6264-2: 2005, with an additional force of 15 N, a slip rate of 50%, a wear test time of 10 minutes, and a test temperature of 20 ° C. A wear test was performed to measure the amount of wear.
The test results were expressed as an index according to the following formula, with the measured value of Comparative Example 1 being 100, and described in the column of “Abrasion amount” in Table 1 below. The smaller the index, the smaller the amount of wear and the better the wear resistance. When the index was 95 or less, it was judged that the wear resistance was effective.
Index = (Measured value / Wear mass of test piece of Comparative Example 1) × 100

Each component shown in Table 1 is as follows.
・ SBR: Nipol 1502 (manufactured by Nippon Zeon)
-BR: Nipol BR 1220 (manufactured by Nippon Zeon)
Acid-modified polyolefin: Maleic anhydride-modified ethylene / 1-butene copolymer (Toughmer MH7020, manufactured by Mitsui Chemicals)
・ Diamine compound 1: 3,3-diaminodiphenyl sulfone (Mitsui Chemicals Fine)
・ Diamine compound 2: 4,4-diaminodiphenyl sulfone (Mitsui Chemicals Fine)
-Stearylamine: Farmin 80 (manufactured by Kao Corporation)
-Acid-modified polyolefin derivative B1: Prepared by the method described above-Acid-modified polyolefin derivative B2: Prepared by the method described above-Acid-modified polyolefin derivative B3: Prepared by the method described above-Acid-modified polyolefin derivative B4: Above-mentioned・ Silane coupling agent: sulfide-based silane coupling agent (Si69, manufactured by Evonik Degussa)
Silica: wet silica (nip seal AQ, CTAB adsorption specific surface area 170 m ² / g, manufactured by Nippon Silica)
・ Carbon black: Show black N339M (manufactured by Showa Cabot)
・ Zinc oxide: Zinc flower 3 types (manufactured by Shodo Chemical Industries)
・ Stearic acid: Beads stearic acid (manufactured by NOF Corporation)
Anti-aging agent: N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine (Antigen 6C, manufactured by Sumitomo Chemical Co., Ltd.)
・ Oil: Extract No. 4 S (made by Showa Shell Sekiyu KK)
・ Sulfur: Oil-treated sulfur (manufactured by Karuizawa Refinery)
-Sulfur-containing vulcanization accelerator (CZ): N-cyclohexyl-2-benzothiazole sulfenamide (Sunseller CM-PO, manufactured by Sanshin Chemical Industry Co., Ltd.)
・ Vulcanization accelerator (DPG): 1,3-diphenylguanidine (Sunceller DG, manufactured by Sanshin Chemical Industry Co., Ltd.)

From the results shown in Table 1 above, the acid-modified polyolefin derivative (B) obtained by reacting the acid-modified polyolefin (b1) and the compound (b2) having an amino group in advance was analyzed with a specific mass ratio (diene rubber (A Example 1-7 mix | blended in 1-40 mass parts) with respect to 100 mass parts expressed the effect excellent in abrasion resistance. Also from the viewpoint of reducing heat generation, it was superior to Comparative Example 1 in reducing heat generation.
By comparison between Comparative Example 3 and Example 1, and Comparative Example 7 and Example 6, the rubber compositions of Example 1 and Example 6 were acidic polyolefin (b1) and compound (b2) having an amino group. Compared with the rubber compositions of Comparative Example 3 and Comparative Example 7 which were introduced without reacting in advance, the abrasion resistance was remarkably excellent.
Moreover, by comparison with Comparative Example 6 and Example 5, the rubber composition of Example 5 was introduced without reacting the acidic polyolefin (b1) and the compound (b2) having an amino group in advance, as described above. Compared with the rubber composition of Comparative Example 6, a tendency to be remarkably excellent in wear resistance was shown.
Comparison of Example 4, Example 5 and Example 6 showed that the use of a diamine compound rather than a monoamine compound can provide an excellent wear resistance effect while maintaining lower heat generation. .
Comparative Example 5 exhibited an excellent effect in wear resistance, but the value of elongation at break was low, and a practically appropriate elongation could not be obtained.

DESCRIPTION OF SYMBOLS 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 9 Inner liner

Claims (8)

A diene rubber (A), an acid-modified polyolefin derivative (B) obtained by previously reacting an acid-modified polyolefin (b1) and an amino group-containing compound (b2),
The rubber composition whose content of the acid-modified polyolefin derivative (B) is 1 to 40 parts by mass with respect to 100 parts by mass of the diene rubber (A).   The rubber composition according to claim 1, wherein the compound (b2) having an amino group is a diamine compound.   The acid-modified polyolefin derivative (B) is a single-screw extruder or a twin-screw kneading extruder, and the acid-modified polyolefin (b1) and the amino group-containing compound (b2) are converted into the melting point of the acid-modified polyolefin (b1). The rubber composition according to claim 1 or 2, which is obtained by reacting by melt-kneading as described above.   The rubber composition according to any one of claims 1 to 3, wherein the acid-modified polyolefin (b1) is a polyolefin having at least one repeating unit selected from the group consisting of ethylene and α-olefin.   The rubber composition according to claim 4, wherein the α-olefin is propylene, 1-butene or 1-octene.   The rubber composition according to any one of claims 1 to 5, wherein the acid-modified polyolefin (b1) is a polyolefin modified with maleic anhydride.   A pneumatic tire using the rubber composition according to claim 1 as a constituent member.   The pneumatic tire according to claim 7, wherein the constituent member is a tire tread.

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