WO2017038475A1

WO2017038475A1 - Rubber composition and tire

Info

Publication number: WO2017038475A1
Application number: PCT/JP2016/074051
Authority: WO
Inventors: 智希岩田; 拓哉影山; 上等　和良
Original assignee: 三菱瓦斯化学株式会社
Priority date: 2015-09-04
Filing date: 2016-08-17
Publication date: 2017-03-09
Also published as: TW201714940A; JP2018172446A

Abstract

A rubber composition which contains (A) an aminoguanidine derivative, (B) a natural rubber and/or a synthetic rubber, (C) an inorganic filler, (D) a silane coupling agent and (E) zinc phosphate.

Description

Rubber composition and tire

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

充填 Filler is a compounding agent used for the purpose of mixing with rubber to reinforce the rubber, add weight or give special functions. Carbon black, which is a typical filler, not only contributes to the improvement (reinforcing effect) of mechanical properties such as elastic modulus and breaking strength of rubber, but also has a function of imparting conductivity.

A method of using an inorganic filler such as silica is known as a method for obtaining a rubber composition having a rubber reinforcing effect similar to carbon black and having a low exothermic property, that is, a low loss property. It is applied to rubber compositions for low fuel consumption tires that are environmentally friendly.

In the inorganic filler-containing rubber composition, when the inorganic filler is compounded, the inorganic filler, particularly hydrophilic silica having a silanol group on the surface has a low affinity with the hydrophobic rubber, and the rubber composition Since it aggregates in the material, it is necessary to increase the affinity between silica and rubber in order to enhance the reinforcement by silica and obtain a low heat generation effect. As the method, synthetic rubber improved in affinity with an inorganic filler by terminal modification with a polar group (see Patent Document 1), or an affinity with an inorganic filler by copolymerizing a polar group-containing monomer. Synthetic rubber having improved properties (see Patent Document 2) and the like are known. As a method for modifying natural rubber and introducing a polar group, a method in which natural rubber is oxidized and then modified with a hydrazide compound having a polar group (see Patent Document 3), a modified natural rubber having a polar group introduced therein and silica are used. A method of further improving the dispersibility of silica by adding a silane coupling agent to the rubber composition containing the rubber composition is known (see Patent Document 4).

Thus, along with the study to improve the dispersibility of silica, since silica is acidic, studies have been conducted to suppress vulcanization delay due to adsorption of a vulcanization accelerator onto silica. For example, in Patent Document 5, vulcanization delay is suppressed by adding polyethylene glycol or amine.

JP 2010-209253 A JP 2011-38009 A JP 2009-108204 A JP 2011-246513 A JP 2001-139727 A

However, polyethylene glycol and amine have a side effect of shortening the molding time, which causes a problem that processability is lowered.

In the future, it is expected that there will be an ever-increasing interest in environmental issues such as carbon dioxide concentration in the atmosphere and air pollution. Adding inorganic fillers such as silica will not reduce the productivity of tires. There is a need for a technology that provides a rubber composition and a tire excellent in low-loss properties that suppress rolling resistance and lead to lower fuel consumption of automobiles.

The present invention has been made in view of the above problems, and in a rubber composition containing an inorganic filler, it is excellent in low loss property and breaking strength, and further ensures both molding time and shortened vulcanization time. An object is to provide a rubber composition and a tire including the rubber composition.

As a result of intensive studies, the present inventors have obtained a rubber composition obtained by mixing zinc phosphate, aminoguanidine derivative, natural rubber and / or synthetic rubber, a filler containing an inorganic filler, and a silane coupling agent. The present inventors have found that the above problems can be solved and have completed the present invention.

That is, the present invention is as follows.
[1]
An aminoguanidine derivative (A),
Natural rubber and / or synthetic rubber (B);
An inorganic filler (C);
A silane coupling agent (D);
Containing zinc phosphate (E),
Rubber composition.
[2]
The inorganic filler (C) contains silica,
[1] The rubber composition according to [1].
[3]
The inorganic filler (C) contains carbon black,
The rubber composition according to [1] or [2].
[4]
The aminoguanidine derivative (A), the natural rubber and / or the synthetic rubber (B), the inorganic filler (C), the silane coupling agent (D), and the zinc phosphate (E) Obtained by mixing at 180 ° C.,
The rubber composition according to any one of [1] to [3].
[5]
The content of the zinc phosphate (E) is 0.01 to 10 parts by mass with respect to 100 parts by mass of the natural rubber and / or synthetic rubber (B).
The rubber composition according to any one of [1] to [4].
[6]
The content of the aminoguanidine derivative (A) is 0.01 to 10 parts by mass with respect to 100 parts by mass of the natural rubber and / or the synthetic rubber (B).
The rubber composition according to any one of [1] to [5].
[7]
The tread includes the rubber composition according to any one of [1] to [6].
tire.

According to the present invention, a rubber composition containing an inorganic filler is excellent in low loss and breaking strength, and further includes a rubber composition that ensures both molding time and shortens vulcanization time, and the rubber composition. A tire can be provided.

Hereinafter, the embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. However, the present invention is not limited to this, and various modifications are possible without departing from the scope of the present invention. It is.

(Rubber composition)
The rubber composition of the present embodiment comprises an aminoguanidine derivative (A), natural rubber and / or synthetic rubber (B) (hereinafter also simply referred to as “rubber component (B)”), and inorganic filler (C). And a silane coupling agent (D) and zinc phosphate (E).

[Aminoguanidine derivative (A)]
The aminoguanidine derivative (A) is not particularly limited, and for example, aminoguanidine, diaminoguanidine, triaminoguanidine, and salts thereof can be used.

The aminoguanidine derivative (A) exhibits strong basicity because the positive charge of the conjugate acid is dispersed and stabilized by a plurality of nitrogen atoms present in the molecule, and is usually a complex (salt) with an acid. Exists.

The aminoguanidine salt is not particularly limited. For example, aminoguanidine carbonate, aminoguanidine hydrochloride, aminoguanidine hydroiodide, aminoguanidine hydrobromide, aminoguanidine hemisulfate, aminoguanidine nitrate, amino Guanidine oxalate, aminoguanidine phosphate, aminoguanidine acetate, aminoguanidine sulfamate, aminoguanidine perchlorate, aminoguanidine silicate, aminoguanidine borate, aminoguanidine phenylphosphinate, etc. It is done.

The diaminoguanidine salt is not particularly limited. For example, diaminoguanidine carbonate, diaminoguanidine hydrochloride, diaminoguanidine hydroiodide, diaminoguanidine hydrobromide, diaminoguanidine hemisulfate, diaminoguanidine nitrate, diamino Guanidine oxalate, diaminoguanidine phosphate, diaminoguanidine acetate, diaminoguanidine sulfamate, diaminoguanidine perchlorate, diaminoguanidine silicate, diaminoguanidine borate, diaminoguanidine phenylphosphinate, etc. It is done.

Examples of the triaminoguanidine salt include, but are not limited to, for example, triaminoguanidine carbonate, triaminoguanidine hydrochloride, triaminoguanidine hydroiodide, triaminoguanidine hydrobromide, triaminoguanidine hemisulfate, Triaminoguanidine nitrate, Triaminoguanidine oxalate, Triaminoguanidine phosphate, Triaminoguanidine acetate, Triaminoguanidine sulfamate, Triaminoguanidine perchlorate, Triaminoguanidine silicate, Triaminoguanidine Examples thereof include borate and triaminoguanidine phenylphosphinate.

Of these aminoguanidine derivatives, aminoguanidine and its salts are preferably used from the viewpoint of availability, and aminoguanidine carbonate and aminoguanidine hydrochloride are more preferably used from the viewpoint of economy.

A polar group is introduced into the rubber component (B) by reacting the hydrazine moiety contained in the aminoguanidine derivative (A) and the rubber component (B) during mixing to introduce a polar group into the rubber component (B). Between the rubber component (B) and the inorganic filler (C), since the affinity with the polar group that the inorganic filler (C) may have (especially silanol groups on the silica surface in the case of silica) improves. Adhesion is improved. And rubber molded objects, such as a tire obtained using the rubber composition of this embodiment, will be excellent in low-loss property.

The effect of shortening the vulcanization time while ensuring a sufficient molding time of the present embodiment is also obtained in the rubber composition in which the zinc phosphate or the aminoguanidine derivative is added individually, but when used in combination. It turns out to be prominent. The reason is not clear, but the composite formed by the reaction of zinc phosphate and aminoguanidine derivative during mixing greatly changes the dispersion state of silica or zinc oxide rather than zinc phosphate or aminoguanidine derivative alone. It is presumed that it was because of

The aminoguanidine derivative (A) can be obtained by a known method. For example, an arbitrary salt can be obtained by a salt exchange reaction or the like.

The content of the aminoguanidine derivative (A) is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, even more preferably 100 parts by weight of the rubber component (B). Is 0.1 to 3 parts by mass. When the content of the aminoguanidine derivative (A) is within the above range, a small amount of polar groups (groups derived from the aminoguanidine derivative (A)) are uniformly present at the double bond sites that the rubber component (B) may have. In addition, aminoguanidine derivatives (A) and zinc phosphate (B) tend to react. Thereby, the workability of the rubber composition is further improved, the affinity between the rubber component (B) and the inorganic filler (C) or zinc oxide is further improved, and the low loss property of the obtained rubber molded body is further improved. It tends to be excellent. Further, the vulcanization time tends to be shortened while securing a sufficient molding time.

[Rubber component (B)]
As the rubber component (B), natural rubber obtained from rubber trees and / or synthetic rubber produced industrially from petroleum or the like can be used. In addition, natural rubber has a large tearing effect and is excellent in fatigue resistance, and synthetic rubber is excellent in wear resistance. Therefore, both rubber types can be arbitrarily mixed for the purpose. In this embodiment, at least a part of the aminoguanidine derivative (A) may be bonded to at least a part of the rubber component (B) via a covalent bond or a non-covalent bond.

(Natural rubber)
The natural rubber is not particularly limited. For example, any shape of natural rubber latex, sheet rubber obtained by coagulating and drying natural rubber latex, and block rubber can be used as a raw material. A main component of natural rubber is polyisoprene.

The sheet rubber is not particularly limited, and examples thereof include those described in “International Quality Packaging Standards for Natural Rubber Grades” (commonly called Green Book). More specifically, ribbed smoked sheet (RSS) dried with smoke smoked sheet, air dried sheet (ADS) coagulated material dried with hot air thoroughly washed with hot air and dried with hot air Examples thereof include a creped, a TC rubber (Technically Classified Rubber), an SP rubber (Super Processing Rubber), an MG rubber, a PP crepe, a softener, and a peptizer-added rubber.

The block rubber is not particularly limited. For example, Standard Malaysian Rubber Rubber (SMR) from Malaysia, Standard Indonesian Rubber (SIR) from Indonesia, Standard Thai Rubber (STR) from Sri Lan, srib from STR Standard Singapore Rubber (SSR) from Singapore, Standard Vietnamese Rubber (SVR) from Vietnam, Indian Standard Natural Rubber (ISNR) from India, CR from China Standard .

Further, rubber that has been solidified after oxidation treatment of natural rubber latex may be used, and oxidation of natural rubber latex can be performed by a known method. For example, according to JP-A-8-81505, natural rubber latex can be oxidized by air-oxidizing natural rubber latex dissolved in an organic solvent at a ratio of 1 to 30% by mass in the presence of a metal-based oxidation catalyst. it can. Further, as described in JP-A-9-136903, a carbonyl compound can be added to natural rubber latex for oxidation. When air oxidation is performed as an oxidation method, as described in JP-A-9-136903, air oxidation may be performed in the presence of a radical generator in order to promote air oxidation. As the radical generator, for example, a peroxide radical generator, a redox radical generator, an azo radical generator and the like are preferably used.

These natural rubber raw materials may be used alone or in combination of two or more.

(Synthetic rubber)
The synthetic rubber is not particularly limited. For example, 1,4-polybutadiene, 1,2-polybutadiene, 1,4-polyisoprene, 3,4-polyisoprene, isobutylene rubber, isoprene-isobutylene rubber, styrene-butadiene rubber Styrene-isoprene rubber, terminal-modified styrene-butadiene rubber, chloroprene rubber, nitrile rubber, ethylene-propylene rubber, propylene-butylene rubber, ethylene-propylene-diene rubber, and the like, and diene rubber having a double bond in the molecule.

The content of the rubber component (B) is preferably 35 to 80% by mass, more preferably 40 to 70% by mass, and further preferably 40 to 60% by mass with respect to the total amount of the rubber composition. . When the content of the rubber component (B) is within the above range, the low loss property and the breaking strength tend to be more excellent.

[Inorganic filler (C)]
The inorganic filler (C) is not particularly limited as long as it is an inorganic filler used in the art. For example, silicon, typical metal, or transition metal oxide; silicon, typical metal, or transition metal hydroxide Hydrates thereof; silicon, typical metal, or transition metal carbonates; and at least one selected from carbon black and the like.

Further, the inorganic filler (C) is a reinforcing filler used for the purpose of enhancing the reinforcing property; and non-reinforcing property used for the purpose of increasing the amount and improving the workability such as rolling property and extrudability. It can also be classified as a filler.

The reinforcing filler is not particularly limited, and examples thereof include silica having active surface, surface-treated clay, carbon black, mica, calcium carbonate, aluminum hydroxide, aluminum oxide, and titanium oxide.

The non-reinforcing filler is not particularly limited. For example, calcium carbonate, clay, talc, diatomaceous earth, pulverized quartz, fused quartz, aluminosilicate, organic acid surface-treated calcium carbonate, magnesium carbonate, zinc carbonate, Examples include calcium silicate and ferric oxide.

Among the above, reinforcing fillers are preferable, and silica and carbon black are more preferable. By using such an inorganic filler (C), the reinforcing property of the rubber composition is further improved, and the affinity between the rubber component (B) and the inorganic filler (C) is further improved, and the resulting rubber There exists a tendency for the low-loss property of a molded object to be more excellent.

The silica is not particularly limited, and for example, wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid) and the like can be used. Further, the BET specific surface area of silica is preferably 40 to 350 m ² / g, more preferably 100 to 300 m ² / g, still more preferably 150 to 250 m ² / g. When the BET surface area of silica is in the above range, the silica particle diameter is appropriate, the tensile strength is further improved, and the hysteresis loss tends to be further reduced.

Carbon black is not particularly limited. For example, General Purpose Furnace (GPF), Fast Extruding Furnace (FEF), Semi-Reinforcing Furnace (SRF), High AbsenceFuranceHAF ISAF), Super Abrasion Furnace (SAF) grade, and the like.

The content of the inorganic filler (C) is preferably 5 to 120 parts by weight, more preferably 20 to 100 parts by weight, and further preferably 30 to 30 parts by weight with respect to 100 parts by weight of the organic component of the rubber composition. 100 parts by mass. When the content of the inorganic filler (C) is within the above range, the processability and reinforcing property of the rubber composition are further improved, and the low loss property of the resulting rubber molded product tends to be more excellent. Here, the “organic component of the rubber composition” refers to the aminoguanidine derivative (A), the rubber component (B), the silane coupling agent (D), and other organic components.

[Silane coupling agent (D)]
The silane coupling agent (D) is not particularly limited. For example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (3-methyldimethoxysilylpropyl) Tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (3-triethoxysilylpropyl) trisulfide, 3 -Sulphides such as trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-trimethoxysilylpropylmethacryloyl monosulfide Silane coupling agent; 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, 3-lauroylthiopropyltriethoxysilane, 2-hexanoylthioethyl Triethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexanoylthiopropyltrimethoxysilane, 3-octanoylthiopropyltri Methoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-octanoylthioethyltrimethoxysilane Thio silane coupling agents such as 2-decanoylthioethyltrimethoxysilane, 2-lauroylthioethyltrimethoxysilane; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyl Mercapto silane coupling agents such as dimethoxysilane; aminosilane silane coupling agents such as 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane; γ-glycidoxypropyltrimethoxysilane, γ-glycidoxy Examples include epoxy silane-based silane coupling agents such as propylmethyldiethoxysilane.

Of these, sulfide-based silane coupling agents are preferred. By using such a silane coupling agent (D), the affinity between the rubber component (B) and the inorganic filler (C) tends to be further improved.

The content of the silane coupling agent (D) is preferably 1 to 20 parts by mass, more preferably 3 to 15 parts by mass, and even more preferably 6 to 100 parts by mass of the inorganic filler (C). ~ 10 parts by mass. When the content of the silane coupling agent (D) is within the above range, the affinity between the rubber component (B) and the inorganic filler (C) tends to be further improved.

[Zinc phosphate (E)]
Zinc phosphate (E) is a compound represented by the chemical formula Zn ₃ (PO ₄ ) ₂ or Zn ₂ P ₂ O ₇ . Among these, it is preferable to use a compound represented by the chemical formula Zn ₃ (PO ₄ ) ₂ , and either an anhydride or a hydrate may be used. Examples of the zinc phosphate (E) include zinc phosphate tetrahydrate (Zn ₃ (PO ₄ ) ₂ · 4H ₂ O) and zinc diphosphate (Zn ₃ (PO) manufactured by Wako Pure Chemical Industries, Ltd. ₄ ) ₂ ) etc. can be obtained as commercial products.

The content of zinc phosphate (E) is preferably 0.01 to 10 parts by weight, more preferably 1 to 7.5 parts by weight, even more preferably 100 parts by weight of the rubber component (B). Is 2 to 5 parts by mass. In addition, when converted to the content of zinc atoms (Zn) itself, the content of zinc phosphate (E) is preferably 0.1 to 8 parts by mass with respect to 100 parts by mass of the rubber component (B). Yes, more preferably 0.3 to 5 parts by mass, still more preferably 0.5 to 3 parts by mass. When the content of zinc phosphate (E) is within the above range, it tends to hardly affect the vulcanization behavior of the rubber composition.

[Other ingredients]
The rubber composition of the present embodiment may contain a compounding agent that is usually used in the rubber industry, if necessary, in addition to the above components. Such a compounding agent is not particularly limited, and examples thereof include an anti-aging agent, a softening agent, a vulcanization accelerator, a vulcanization acceleration aid, and a vulcanization agent. As these compounding agents, commercially available products can be suitably used.

(Anti-aging agent)
The anti-aging agent is not particularly limited, and examples thereof include naphthylamine compounds, p-phenylenediamine compounds, hydroquinone derivatives, bis, tris, polyphenol compounds, diphenylamine compounds, quinoline compounds, monophenol compounds. Thiobisphenol compounds, hinders, phenol compounds and the like. Of these, amine-based anti-aging agents are preferable from the viewpoint of further anti-aging effects, and p-phenylenediamine-based compounds and diphenylamine-based compounds are more preferable.

The diphenylamine compound is not particularly limited. For example, 4,4 ′-(α-methylbenzyl) diphenylamine, 4,4 ′-(α, α-dimethylbenzyl) diphenylamine, p- (p-toluenesulfonylamide) Examples thereof include diphenylamine and 4,4′-dioctyldiphenylamine. Among these, 4,4 ′-(α-methylbenzyl) diphenylamine is most preferable from the viewpoint of higher antiaging effect.

Further, the p-phenylenediamine compound is not particularly limited. For example, N, N′-diphenyl-p-phenylenediamine, N-isopropyl-N′-phenyl-p-phenylenediamine, N, N′-di -2-naphthyl-p-phenylenediamine, N-cyclohexyl-N′-phenyl-p-phenylenediamine, N-phenyl-N ′-(3-methacryloyloxy-2-hydroxypropyl) -p-phenylenediamine, N, N′-bis (1-methylheptyl) -p-phenylenediamine, N, N′-bis (1,4-dimethylpentyl) -p-phenylenediamine, N, N′-bis (1-ethyl-3-methyl) Pentyl) -p-phenylenediamine, N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, and the like. Among these, higher anti-aging effect and a cost N-(1,3-dimethylbutyl)-N'-phenyl -p- phenylenediamine is most preferred.

The content of the antioxidant is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the rubber component (B).

(Softener)
The softening agent is not particularly limited, and examples thereof include mineral oil-based softeners derived from petroleum and coal tar, vegetable oil-based softeners derived from fatty oils and pine trees, and synthetic resin-based softeners. These softeners may be used alone or in combination of two or more.

(Vulcanization accelerator)
The vulcanization accelerator is not particularly limited. For example, thiazol compounds such as mercaptobenzothiazol and di-2-benzothiazolyl disulfide; N-cyclohexyl-2-benzothiazolylsulfenamide Sulfenamide compounds such as N, N′-dicyclohexyl-2-benzothiazolylsulfenamide, N′-tert-butyl-2-benzothiazolylsulfenamide; guanidine compounds such as diphenylguanidine . These vulcanization accelerators may be used alone or in combination of two or more.

The content of the vulcanization accelerator is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the rubber component (B).

(Vulcanization accelerator)
Furthermore, in this embodiment, in order to further improve the effect of the vulcanization accelerator, it is preferable to use a vulcanization acceleration aid. The vulcanization acceleration aid is not particularly limited, and examples thereof include zinc compounds such as zinc oxide and higher fatty acids such as stearic acid. Among these, zinc oxide is preferable, and those treated with an amine dispersant or a wetting agent can be used.

Zinc phosphate (E) also acts as a vulcanization acceleration aid in the same manner as zinc oxide. Therefore, for example, when zinc oxide is used as the zinc source, the total content of zinc oxide and zinc phosphate is determined by the rubber component ( B) The amount is preferably 0.01 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, and further preferably 1 to 5 parts by mass with respect to 100 parts by mass.

The content of zinc oxide is preferably 0.01 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, and still more preferably 0.8 to 100 parts by mass of the rubber component (B). Is 5 parts by mass. Further, when converted to the content of zinc atoms (Zn) itself, the content of zinc oxide is preferably 0.008 to 8 parts by mass, more preferably 100 parts by mass of the rubber component (B). Is 0.1 to 5 parts by mass, more preferably 0.5 to 3 parts by mass. When the content of zinc oxide is within the above range, characteristics such as molding time and tensile strength of the rubber composition tend to be highly balanced.

(Vulcanizing agent)
The vulcanizing agent is not particularly limited as long as it is usually used in the art, and examples thereof include sulfur and peroxides. Among these, sulfur is preferable.

The content of the vulcanizing agent is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 3 parts by mass with respect to 100 parts by mass of the rubber component (B). When the content of the vulcanizing agent is 0.1 parts by mass or more, vulcanization proceeds sufficiently. Further, when the content of the vulcanizing agent is 5 parts by mass or less, the so-called coaching time becomes long, and the rubber tends to be prevented from being burnt during kneading.

The rubber composition of this embodiment comprises an aminoguanidine derivative (A), a rubber component (B), an inorganic filler (C), a silane coupling agent (D), and zinc phosphate (E) at 20 to 180 ° C. It is preferable that it is obtained by mixing with. The mixing temperature is preferably 20 to 180 ° C, more preferably 50 to 160 ° C, and further preferably 80 to 160 ° C. In such a rubber composition, the reaction of the aminoguanidine derivative (A) to the rubber component (B) tends to proceed more appropriately while the decomposition of the aminoguanidine derivative (A) is suppressed. Therefore, the affinity between the rubber component (B) and the inorganic filler (C) is further improved, and the low loss property of the obtained rubber molded product tends to be more excellent.

[Method for producing rubber composition]
Next, the manufacturing method of the rubber composition of this embodiment is described. The rubber composition of this embodiment is a method in which an aminoguanidine derivative (A), a rubber component (B), an inorganic filler (C), a silane coupling agent (D), and zinc phosphate (E) are mixed. If it does not specifically limit.

In mixing, a mixer, an extruder, a kneader or the like can be used. Among these, it is preferable to mix with a kneader from the viewpoint of improving dispersibility. The method for adding the aminoguanidine derivative (A) and zinc phosphate (E) to the mixer, extruder, kneader, etc. is not particularly limited. For example, the method of adding the powder as it is, or dissolving it in a solvent. The method of adding as a solution and the method of adding as an emulsion solution are mentioned.

The mixing temperature is preferably 20 to 180 ° C, more preferably 50 to 160 ° C, and further preferably 80 to 160 ° C. When the mixing temperature is 20 to 180 ° C., the rubber component (B) and the aminoguanidine derivative (A), and the zinc phosphate (E) and the aminoguanidine derivative (A) are mixed more uniformly, and these reactions are performed. Can proceed more appropriately, and further, thermal decomposition of the aminoguanidine derivative (A) tends to be suppressed.

The kneading time is preferably 0.5 to 30 minutes, more preferably 2 to 10 minutes, and further preferably 2 to 7 minutes. When the kneading time is 0.5 to 30 minutes, the rubber component (B) and the aminoguanidine derivative (A), and the zinc phosphate (E) and the aminoguanidine derivative (A) are sufficiently maintained while maintaining the productivity. Tend to react.

The reaction atmosphere is preferably performed in the presence of oxygen such as under air. Oxygen tends to promote the radical reaction between the rubber component (B) and the aminoguanidine derivative (A).

For the purpose of adjusting the reactivity of the aminoguanidine derivative (A), a polymerization initiator (reaction promotion) agent or a polymerization inhibitor (reaction delay) agent can be used. Polymerization initiators include benzoyl peroxide, hydrogen peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, 2,2-azobisisobutyronitrile, 2,2 -Azobis (2-diaminopropane) hydrochloride, 2,2-azobis (2-diaminopropane) dihydrochloride, 2,2-azobis (2,4-dimethylvaleronitrile), potassium persulfate, sodium persulfate, ammonium persulfate Etc. In order to lower the reaction temperature, it is preferable to use a redox polymerization initiator. Examples of the reducing agent to be combined with the peroxide in the redox polymerization initiator include tetraethylenepentamine, mercaptans, acidic sodium sulfite, reducing metal ions, ascorbic acid and the like. These may be used alone or in combination of two or more.

Examples of polymerization inhibitors include stable radical substances such as diphenylpicrylhydrazyl, galvinoxyl, and ferdazil, and those that easily generate stable radicals when added to radicals such as enzymes, phenol derivatives, benzoquinone derivatives, nitro compounds, etc. Is mentioned. These may be used alone or in combination of two or more.

〔tire〕
The tire according to this embodiment includes the rubber composition, and a tire including the rubber composition in a tread is particularly preferable. Thereby, the tire of this embodiment becomes excellent in low fuel consumption. If it is a method to manufacture so that the said rubber composition may be included, the manufacturing method of the tire of this embodiment is not specifically limited, It can manufacture in accordance with a conventional method. In addition, as a gas filled in the tire, an inert gas such as nitrogen, argon, helium, or the like can be used in addition to normal or air with adjusted oxygen partial pressure.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Example 1]
According to the composition shown in Table 1, natural rubber coagulated product (trade name “RSS # 1”, manufactured by Kato Sangsho Co., Ltd.), silica (trade name “Nip Seal AQ”, manufactured by Tosoh Silica Co., Ltd.) , BET surface area = 207 m ² / g), silane coupling agent (bis (3-triethoxysilylpropyl) tetrasulfide, manufactured by Evonik Japan Co., Ltd.), zinc oxide (manufactured by Wako Pure Chemical Industries, Ltd.), phosphoric acid zinc tetrahydrate _{_{_{(Zn 3 (PO 4) 2}}} · 4H 2 O, manufactured by Wako Pure Chemical Industries, Ltd.), (manufactured by Wako Pure Chemical Industries, Ltd.) stearic acid, aminoguanidine carbonate (Tokyo Kasei Kogyo ( Co., Ltd.) was kneaded at 145 ° C. for 5 minutes in a lab plast mill (manufactured by Toyo Seiki Seisakusho). Thereafter, the obtained kneaded material was once cooled to 55 ° C., to which sulfur (manufactured by Hosoi Chemical Co., Ltd., 250 μm) and CBS (N-cyclohexyl-2-benzothiazolylsulfenamide) as a vulcanization accelerator, Wako Pure Chemical Industries, Ltd.) and DPG (diphenylguanidine, Wako Pure Chemical Industries, Ltd.) were added and kneaded at 90 ° C. for 3 minutes to prepare an unvulcanized rubber composition.

Subsequently, the vulcanized rubber composition was vulcanized using a press (made by Kitagawa Seiki Co., Ltd.) at 145 ° C. and 10 MPa for 1.5 times the t90 value (minute) (19 to 40 minutes). Obtained. t90 is defined as 90% of the difference between the maximum value and the minimum value of the torque in the evaluation by the vulcanization tester + the time until reaching the minimum value.

[Comparative Example 1]
The same operation as in Example 1 except that aminoguanidine carbonate and zinc phosphate tetrahydrate were not used, and the amount of zinc oxide used was changed so that the number of moles of zinc atoms was the same as in Example 1. Thus, an unvulcanized rubber composition was prepared to obtain a vulcanized rubber composition.

Using the obtained vulcanized rubber composition, the exothermic property and tensile breaking strength were measured and evaluated by the following methods. The results are shown in Table 1.

(1) Exothermic property The vulcanized rubber composition was subjected to loss tangent (tan δ) at a temperature of 50 ° C., a strain of 0.05%, and a frequency of 10 Hz using a dynamic viscoelasticity measuring device (DMS6100 manufactured by Seiko Instruments Inc.). ) Was measured, and the value of Comparative Example 1 in Table 1 was taken as 100 and indicated as an index. The smaller the index value, the lower the tan δ, indicating that the rubber composition is less exothermic.

(2) Tensile strength at break The above vulcanized rubber composition was subjected to a tensile test in accordance with JIS K6251: 2010, the tensile strength at break was measured, and the value of Comparative Example 1 in Table 1 was expressed as an index. A larger index value indicates a higher tensile breaking strength.

(3) Molding time / Vulcanization time The molding time (3-1) and vulcanization time (3-2) shown below are measured, and the ratio of the molding time to the vulcanization time (molding time / vulcanizing time) is determined. The value of Comparative Example 1 in Table 1 was taken as 100 and indicated as an index. A larger index value indicates that the vulcanization time can be shortened while securing a sufficient molding time.

(3-1) Molding time JIS K 6300-2: 2001 die vulcanization is performed on the unvulcanized rubber composition using a vulcanization tester (rotorless rheometer RLR-4 manufactured by Toyo Seiki Seisakusho Co., Ltd.). According to the test A method, t10 was measured at a temperature of 145 ° C., an amplitude angle of ± 1 °, and a frequency of 100 cpm. t10 is 10% of the difference between the maximum value and the minimum value of the torque + the time required to reach the minimum value, and is used as an index of the flow time during vulcanization molding, that is, the workability or molding time. It shows that it is excellent in a moldability, so that this time is long.

(3-2) Vulcanization Time JIS K 6300-2: 2001 Die vulcanization is applied to the unvulcanized rubber composition using a vulcanization tester (rotorless rheometer RLR-4 manufactured by Toyo Seiki Seisakusho Co., Ltd.). According to the sulfur test A method, t90 was measured at a temperature of 145 ° C., an amplitude angle of ± 1 °, and a frequency of 100 cpm. t90 is 90% of the difference between the maximum value and the minimum value of the torque + the time required to reach the minimum value, and is used as an index of the vulcanization time. It shows that it is excellent in productivity, so that this time is short.

In Table 1, each component of the compounding prescription indicates part by mass, and the value in () indicates part by mass converted to zinc atom.

From Table 1, the rubber composition in which aminoguanidine phosphate, natural rubber, silica and silane coupling agent are mixed is excellent in low exothermic property, has high tensile breaking strength, and is added while ensuring sufficient molding time. It can be seen that the sulfurization time can be shortened.

This application is based on a Japanese patent application (Japanese Patent Application No. 2015-174392) filed with the Japan Patent Office on September 4, 2015, the contents of which are incorporated herein by reference.

The rubber composition of the present invention has industrial applicability as a tire material and the like.

Claims

An aminoguanidine derivative (A),
Natural rubber and / or synthetic rubber (B);
An inorganic filler (C);
A silane coupling agent (D);
Containing zinc phosphate (E),
Rubber composition.
The inorganic filler (C) contains silica,
The rubber composition according to claim 1.
The inorganic filler (C) contains carbon black,
The rubber composition according to claim 1 or 2.
The aminoguanidine derivative (A), the natural rubber and / or the synthetic rubber (B), the inorganic filler (C), the silane coupling agent (D), and the zinc phosphate (E) Obtained by mixing at 180 ° C.,
The rubber composition according to any one of claims 1 to 3.
The content of the zinc phosphate (E) is 0.01 to 10 parts by mass with respect to 100 parts by mass of the natural rubber and / or synthetic rubber (B).
The rubber composition according to any one of claims 1 to 4.
The content of the aminoguanidine derivative (A) is 0.01 to 10 parts by mass with respect to 100 parts by mass of the natural rubber and / or the synthetic rubber (B).
The rubber composition according to any one of claims 1 to 5.
The tread contains the rubber composition according to any one of claims 1 to 6,
tire.