TW201945425A - Additive for rubbers, uncrosslinked rubber composition, crosslinked rubber and tire - Google Patents

Abstract

An additive for rubbers, which contains a hydrogenated petroleum resin that is a hydrogenated product of a polymer of an unsaturated hydrocarbon, and which is configured such that: the unsaturated hydrocarbon contains an aromatic compound having an aromatic ring and an alicyclic compound having a five-membered ring; the aromatic compound contains an indene compound having an indene skeleton; and the content of the indene compound is 15-60% by mass based on the total amount of the unsaturated hydrocarbon.

Description

Additives for rubber, uncrosslinked rubber composition, crosslinked rubber and tire

The present invention relates to an additive for rubber, an uncrosslinked rubber composition, a crosslinked rubber, and a tire.

In order to impart various characteristics to rubber materials, additives for rubber have been used. For example, Patent Document 1 discloses a composition for a tire tread including at least one elastomer, and a specific hydrocarbon polymer additive of a dicyclopentadiene, a cyclopentadiene, and a methylcyclopentadiene matrix.
Prior art literature patent literature

Patent Document 1: Japanese Patent Publication No. 2015-523430

[Problems to be solved by the invention]

In recent years, from the viewpoint of improving the fuel efficiency performance of tires, good rolling resistance characteristics have been strongly demanded. On the other hand, from the viewpoint of safety, excellent tire grip performance is strongly required for tires. However, it is difficult to have both good rolling resistance characteristics and excellent wet grip performance.

An object of the present invention is to provide an additive for rubber that can provide good rolling resistance characteristics and excellent wet grip performance. Another object of the present invention is to provide an uncrosslinked rubber composition containing the aforementioned rubber additive, a crosslinked rubber obtained by cross-linking the uncrosslinked rubber composition, and a tire containing the crosslinked rubber in a tread portion.
[Technical means to solve the problem]

One aspect of the present invention relates to an additive for rubber comprising a hydrogenated petroleum resin as a hydride of a polymer of an unsaturated hydrocarbon, the unsaturated hydrocarbon containing an aromatic compound having an aromatic ring, and a five-membered lipid The cyclic compound and the aromatic compound contain an indene compound having an indene skeleton, and the content of the indene compound is 15 to 60% by mass based on the total amount of unsaturated hydrocarbons.

In one aspect, the alicyclic compound may include a DCPD (dicyclopentadiene) -based compound having a dicyclopentadiene skeleton.

In one aspect, the content of the alicyclic compound may be 40 to 85% by mass based on the total amount of unsaturated hydrocarbons.

In one aspect, the ratio of the indene compound to the aromatic compound may be 50% by mass or more.

In one aspect, the aromatic content in the hydrogenated petroleum resin may be 0.3 to 30%.

In one aspect, the softening point of the hydrogenated petroleum resin may be 80 ~ 150 ° C.

In one aspect, the weight average molecular weight of the hydrogenated petroleum resin may be 200-1000.

Another aspect of the present invention relates to an uncrosslinked rubber composition containing a rubber component, the aforementioned rubber additive, and a crosslinking agent.

Another aspect of the present invention relates to a crosslinked rubber obtained by crosslinking the above-mentioned uncrosslinked rubber composition.

Another aspect of the present invention relates to a tire containing the above-mentioned crosslinked rubber on a tread portion.
[Effect of the invention]

According to the present invention, there is provided an additive for rubber capable of imparting good rolling resistance characteristics and excellent wet grip performance. The present invention also provides an uncrosslinked rubber composition containing the rubber additive, a crosslinked rubber obtained by crosslinking the uncrosslinked rubber composition, and a tire containing the crosslinked rubber on a tread portion.

Hereinafter, a preferred embodiment of the present invention will be described.

＜ Additives for rubber ＞
The rubber additive according to this embodiment contains a hydrogenated petroleum resin which is a hydride of a polymer of an unsaturated hydrocarbon. In this embodiment, the unsaturated hydrocarbon contains an aromatic compound having an aromatic ring and an alicyclic compound having a five-membered ring. The aromatic compound contains an indene compound having an indene skeleton. Furthermore, the content of the indene-based compound in the unsaturated hydrocarbon is 15 to 60% by mass based on the total amount of the unsaturated hydrocarbon.

Such an additive for rubber can impart good rolling resistance characteristics and excellent wet grip performance to a rubber material.

Regarding rolling resistance characteristics, it is known that the smaller the loss coefficient (tan δ) measured near the frequency of 10 to 100 Hz and 60 ° C by the dynamic viscoelasticity test of a rubber material, the better the rolling resistance characteristics. On the other hand, with regard to wet grip performance, it is known that the greater the loss coefficient (tan δ) measured by the dynamic viscoelasticity test of a rubber material near a frequency of 10 to 100 Hz and 0 ° C, the better the wet grip performance. Excellent.

Both rolling resistance characteristics and wet grip performance are characteristics related to hysteresis loss of rubber materials. In general, if the hysteresis loss is increased, the grip is improved and the braking performance is improved, but the rolling resistance is also increased, resulting in poor fuel efficiency. In this way, since the grip performance and the rolling resistance characteristics are in the opposite relationship, it is difficult to satisfy both the good rolling resistance characteristics and the excellent wet grip performance.

Since the additive for rubber of this embodiment can be added to the rubber material, the loss coefficient (tanδ) at high temperature (for example, 60 ° C) in the dynamic viscoelasticity test can be kept low, and the low temperature (for example, 0 ° C) can be increased ) Under the loss coefficient (tanδ), so it can impart good rolling resistance characteristics and excellent wet grip performance to rubber materials.

The inventors and others have considered the mechanism for exerting the above effects as follows. In general, the peak of the loss coefficient (tan δ) of the rubber component is in a temperature region lower than 0 ° C. Moreover, it is known that the softening point of petroleum resin (or hydrogenated petroleum resin) is usually higher than the glass transition temperature (Tg) of the rubber component. Therefore, by adding petroleum resin (or hydrogenated petroleum resin) to the rubber material, the peak of the loss coefficient (tanδ) can be shifted to the high temperature side, and the loss coefficient (tanδ) near 0 ° C can be increased. However, in general petroleum resins, there is a problem that a loss coefficient (tan δ) near 60 ° C. is also increased due to a peak shift, and rolling resistance is increased.

Here, in general petroleum resins, in order to increase the softening point and improve the effect of improving wet grip performance, it is necessary to increase the molecular weight. On the other hand, since the hydrogenated petroleum resin according to this embodiment has a rigid condensed ring skeleton derived from an indene-based compound, a high softening point can be obtained even at a low molecular weight. Therefore, in this embodiment, the wet grip performance can be efficiently improved by using a hydrogenated petroleum resin having a small molecular weight. That is, the hydrogenated petroleum resin according to this embodiment can achieve improved wet grip performance with a smaller molecular weight than a general petroleum resin.

In addition, in this embodiment, since the molecular weight of the hydrogenated petroleum resin is small, the hydrogenated petroleum resin becomes easier to enter between the molecules of the rubber component, and the compatibility between the rubber component and the hydrogenated petroleum resin is improved. It is considered that the peak of the loss coefficient (tan δ) becomes a steeper peak by improving the compatibility, and the loss coefficient (tan δ) near 60 ° C. can be suppressed to be low.

Hereinafter, the rubber additive according to this embodiment will be described in detail.

Hydrogenated petroleum resins are hydrides of polymers (petroleum resins) of unsaturated hydrocarbons. The hydrogenated petroleum resin may be a partial hydride or a complete hydride of the petroleum resin, but is preferably a partial hydride.

The unsaturated hydrocarbon contains an aromatic compound having an aromatic ring and an alicyclic compound having a five-membered ring. Both the aromatic compound and the alicyclic compound are compounds which have a carbon-carbon double bond as a polymerizable group and can be copolymerized with each other.

The unsaturated hydrocarbon may be, for example, a C5 fraction and a C9 fraction collected from a petroleum-derived feedstock through thermal decomposition or the like. The petroleum-derived C5 fraction mainly contains the above-mentioned alicyclic compounds, and the petroleum-derived C9 fraction mainly contains the above-mentioned aromatic compounds.

In this embodiment, the unsaturated hydrocarbon contains an indene-based compound having an indene skeleton as an aromatic-based compound. Here, the indene skeleton means a carbon skeleton possessed by indene (C ₉ H ₈ ). By using an indene compound, a rigid condensed ring skeleton is introduced into the hydrogenated petroleum resin, and the softening point of the hydrogenated petroleum resin becomes high. Examples of the indene-based compound include indene and methylindene.

The content of the indene-based compound in the unsaturated hydrocarbon is 15% by mass or more based on the total amount of the unsaturated hydrocarbon. Thereby, a hydrogenated petroleum resin having a low molecular weight and a high softening point can be obtained. The content of the indene compound is preferably 20% by mass or more, and more preferably 30% by mass or more from the viewpoint of obtaining a lower molecular weight and a higher softening point.

The content of the indene compound in the unsaturated hydrocarbon is 60% by mass or less based on the total amount of the unsaturated hydrocarbon. When the indene-based compound exceeds 60% by mass, the unsaturated hydrocarbon tends to be difficult to polymerize. The content of the indene-based compound is preferably 58% by mass or less, and more preferably 56% by mass or less from the viewpoint of easily obtaining a polymer having a sufficient molecular weight.

The ratio of the indene compound to the aromatic compound may be, for example, 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more. The ratio of the indene compound to the aromatic compound may be 100% by mass.

The aromatic compound may further include a compound other than an indene compound. The compound is not particularly limited, and examples thereof include a styrene-based compound having a styrene skeleton. Examples of the styrene-based compound include styrene and methylstyrene.

The alicyclic compound is a compound having a five-membered ring and no aromatic ring. Examples of the alicyclic compound include a DCPD-based compound having a dicyclopentadiene skeleton, and a CPD (cyclopentadiene) -based compound having a cyclopentadiene skeleton. Here, the dicyclopentadiene skeleton means a carbon skeleton possessed by dicyclopentadiene. The so-called cyclopentadiene skeleton means a carbon skeleton possessed by cyclopentadiene.

The unsaturated hydrocarbon preferably has a DCPD-based compound as the alicyclic compound. Examples of the DCPD-based compound include dicyclopentadiene and methyldicyclopentadiene.

Examples of the CPD-based compound include cyclopentadiene and methylcyclopentadiene.

The ratio of the DCPD-based compound to the alicyclic compound may be, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, or 100% by mass.

The content of the alicyclic compound in the unsaturated hydrocarbon is based on the total amount of the unsaturated hydrocarbon, and may be, for example, 40% by mass or more, preferably 42% by mass or more, and more preferably 44% by mass or more. Thereby, there is a tendency that the polymerization reaction can be easily performed, and the target polymer can be easily obtained. The content of the alicyclic compound in the unsaturated hydrocarbon is, based on the total amount of the unsaturated hydrocarbon, for example, 85% by mass or less, preferably 80% by mass or less, and more preferably 70% by mass or less. Accordingly, since the aromatic content is relatively increased, there is a tendency that a hydrogenated petroleum resin having high compatibility with rubber components can be easily obtained.

An unsaturated hydrocarbon, the content of the aromatic compound content of _{C. 1} and the compound of the alicyclic C ₂ C ratio of ₁ / C ₂ (mass ratio) is preferably 0.25 or more, more preferably 0.43 or more. Accordingly, since the aromatic content is relatively increased, there is a tendency that a hydrogenated petroleum resin having high compatibility with rubber components can be easily obtained. The ratio C ₁ / C _{2 is} preferably 1.38 or less, and more preferably 1.27 or less. Thereby, there is a tendency that the polymerization reaction can be easily performed, and the target polymer can be easily obtained.

The unsaturated hydrocarbon may further contain components other than the aromatic compound and the alicyclic compound. Examples of components other than the above-mentioned aromatic compounds and the above-mentioned alicyclic compounds include aliphatic compounds having no cyclic structure, alicyclic compounds having no five-membered ring, heterocyclic compounds having a heterocyclic ring, and the like. . Examples of the aliphatic compound include isoprene and isoprene. Examples of the heterocyclic compound include coumarin and the like. The content of other components is based on the total amount of unsaturated hydrocarbons, preferably 5 mass% or less, more preferably 1 mass% or less, and also 0 mass%.

The polymer of the unsaturated hydrocarbon (hereinafter, also referred to as a petroleum resin) may be a polymer having a first structural unit derived from the alicyclic compound and a second structural unit derived from the aromatic compound. The content of the first structural unit in the petroleum resin is equivalent to the content of the above-mentioned alicyclic compound in the unsaturated hydrocarbon, and the content of the second structural unit in the petroleum resin is equivalent to the content of the above-mentioned aromatic compound in the unsaturated hydrocarbon. Petroleum resins have structural units derived from indene compounds, so they can have both a high softening point and a low molecular weight in their hydrides.

Petroleum resins can be obtained by the polymerization of unsaturated hydrocarbons. The polymerization method of the unsaturated hydrocarbon is not particularly limited, and can be appropriately selected from known polymerization methods.

In a preferred aspect, the petroleum resin may be obtained by thermal polymerization of an unsaturated hydrocarbon. The method of thermal polymerization is not particularly limited, and for example, it can be carried out by heating a raw material composition containing an unsaturated hydrocarbon to a specific reaction temperature.

The reaction temperature for thermal polymerization is not particularly limited, and may be, for example, 250 ° C or higher, preferably 260 ° C or higher, and more preferably 270 ° C or higher. The reaction temperature for thermal polymerization may be, for example, 300 ° C or lower, preferably 290 ° C or lower, and more preferably 280 ° C or lower.

The reaction time of the thermal polymerization (the time for maintaining the reaction system at the above-mentioned reaction temperature) is not particularly limited, and may be, for example, 30 to 180 minutes, preferably 60 to 120 minutes.

The raw material composition for thermal polymerization may further contain components other than unsaturated hydrocarbons. For example, the petroleum-derived C5 fraction and C9 fraction may contain a non-polymerizable hydrocarbon that does not have a polymerizable group and does not participate in thermal polymerization in addition to the aromatic compounds and alicyclic compounds described above. The raw material composition for thermal polymerization may further contain such a non-polymerizable hydrocarbon. Examples of the non-polymerizable hydrocarbon include a saturated hydrocarbon (such as an alkane and a cycloalkane), and an aromatic hydrocarbon (such as benzene and toluene).

When a component other than an unsaturated hydrocarbon is contained in the raw material composition, it can be removed, for example, by light-weight component removal (distillation) after thermally polymerizing the unsaturated hydrocarbon.

Hydrogenated petroleum resin is a hydride of petroleum resin. As described above, the hydrogenated petroleum resin may be a partial hydride or a complete hydride of the petroleum resin, but is preferably a partial hydride. That is, the hydrogenated petroleum resin may be obtained by hydrogenating a part or all of the aromatic ring of the petroleum resin, or may be obtained by hydrogenating a part of the aromatic ring of the petroleum resin.

The aromatic content in the hydrogenated petroleum resin may be, for example, 30% or less, and preferably 20% or less.

The lower limit of the aromatic content in the hydrogenated petroleum resin is not particularly limited, and may be, for example, 0.3% or more, preferably 3% or more, more preferably 5% or more, and even more preferably 8% or more. As a result, the compatibility between the hydrogenated petroleum resin and the rubber component is further improved, and the effect of the invention that is more remarkable can be obtained.

In addition, in this specification, the aromatic content in hydrogenated petroleum resin is measured using ¹ H-NMR, and the amount of hydrogen (M ₂ ) bonded to the aromatic ring in the hydrogenated petroleum resin is measured relative to the total amount of hydrogen (M ₁ ) Ratio (M ₂ / M ₁ ), and the ratio (M ₂ / M ₁ ) is expressed as a percentage.

The softening point of the hydrogenated petroleum resin may be, for example, 80 ° C or higher, preferably 90 ° C or higher, and more preferably 100 ° C or higher. With the higher softening point of the hydrogenated petroleum resin, the improvement effect of wet grip performance can be exerted more significantly. The upper limit of the softening point of the hydrogenated petroleum resin is not particularly limited, and may be, for example, 150 ° C or lower, preferably 130 ° C or lower, and more preferably 120 ° C or lower. If it is such a softening point, there exists a tendency for workability to become favorable.

In addition, the softening point of hydrogenated petroleum resin means the value measured by the method of DP70 of Mettler-Toledo by the method of ASTM D6090.

The weight average molecular weight of the hydrogenated petroleum resin may be, for example, 1,000 or less, preferably 700 or less, and more preferably 600 or less. Thereby, the compatibility of the hydrogenated petroleum resin with the rubber component is further improved, and the loss coefficient (tan δ) around 60 ° C can be suppressed to be lower. The lower limit of the weight average molecular weight of the hydrogenated petroleum resin is not particularly limited, and may be, for example, 200 or more, preferably 300 or more, and more preferably 350 or more.

The weight-average molecular weight of the hydrogenated petroleum resin is a value obtained by measurement by GPC (gel permeation chromatography) and standard polystyrene conversion.

Hydrogenated petroleum resin can be obtained by hydrogenating an unsaturated hydrocarbon polymer (petroleum resin). The method for obtaining a hydride by hydrogenating a petroleum resin is not particularly limited, and a known method can be used. For example, hydrogenation can be performed by flowing petroleum resin in a reactor filled with a hydrogenation catalyst, and contacting the hydrogenation catalyst with the petroleum resin in the presence of hydrogen.

The hydrogenation catalyst is not particularly limited, and examples thereof include nickel-based catalysts, palladium-based catalysts, and platinum-based catalysts.

The conditions of the hydrogenation reaction can be appropriately changed according to the aromatic content required for the hydrogenated petroleum resin. The hydrogen pressure in the hydrogenation reaction may be, for example, 5 MPa or more, and preferably 10 MPa or more. The hydrogen pressure in the hydrogenation reaction may be, for example, 30 MPa or less, and preferably 20 MPa or less. The reaction temperature in the hydrogenation reaction may be, for example, 200 ° C or higher, and preferably 230 ° C or higher. The reaction temperature in the hydrogenation reaction may be, for example, 310 ° C or lower, and preferably 300 ° C or lower.

The petroleum resin may be dissolved in a solvent and circulated in the reactor. The solvent may be any solvent that can dissolve petroleum resins and has no adverse effect on hydrogenation. Examples of the solvent include kerosene and methylcyclohexane. The solvents may be used singly or in combination of two or more kinds.

<Uncrosslinked rubber composition>
The non-crosslinked rubber composition according to this embodiment contains a rubber component, the aforementioned rubber additive, and a crosslinking agent. The crosslinked rubber obtained by cross-linking the above-mentioned uncrosslinked rubber composition, for example, when used in a tread portion of a tire, can exhibit good rolling resistance characteristics and excellent wet grip performance.

The rubber component is not particularly limited, and examples thereof include natural rubber (NR), butadiene rubber (BR), nitrile rubber, silicone rubber, isoprene rubber (IR), and styrene-butadiene. Rubber (SBR), isoprene-butadiene rubber, styrene-isoprene-butadiene rubber, ethylene-propylene-diene rubber, halogenated butyl rubber, halogenated isoprene rubber, halogenated isobutylene Copolymers, chloroprene rubber (CR), butyl rubber, and halogenated isobutylene-p-methylstyrene rubber. Among these, from the viewpoints of strength, processability, and price, preferred are butadiene rubber (BR), styrene-butadiene rubber (SBR), and natural rubber. The rubber component may be used singly or in combination of two or more kinds.

The glass transition temperature (Tg) of the rubber component may be, for example, 0 ° C or lower, and preferably -20 ° C or lower. The glass transition temperature (Tg) of the rubber component may be, for example, -120 ° C or higher, and preferably -100 ° C or higher. In addition, in this specification, the glass transition temperature of a rubber component means the value measured using DSC (Differential scanning calorimetry).

As the cross-linking agent, those generally used in cross-linking of rubber can be used without particular limitation, and can be appropriately selected according to the rubber component. Examples of the cross-linking agent include sulfur cross-linking agents such as sulfur, morpholine disulfide, and alkylphenol disulfide; cyclohexanone peroxide, methyl ethyl acetate, and tert-butyl isobutyrate. Esters, tert-butyl peroxybenzoate, benzamidine peroxide, lauryl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 1,3-bis (tert-butyl peroxyisopropyl Organic peroxide crosslinking agents such as propyl) benzene. The crosslinking agent may be used singly or in combination of two or more kinds.

The content of the crosslinking agent is preferably from 0.1 to 5 parts by mass, more preferably from 0.5 to 3 parts by mass, and even more preferably from 1 to 2 parts by mass based on 100 parts by mass of the rubber component.

The non-crosslinked rubber composition of this embodiment may further include various reinforcing agents, fillers, rubber extenders, softeners, and the like used in the field of the rubber industry. Each component may be used alone or in combination of two or more.

Examples of the reinforcing agent include carbon black and silicon dioxide.

Carbon black can be used as a reinforcing agent because it can obtain effects such as improvement of abrasion resistance and rolling resistance characteristics of crosslinked rubber, prevention of cracks or cracks caused by ultraviolet rays (prevention of ultraviolet deterioration), and the like. There is no particular limitation on the type of carbon black, and carbon blacks such as furnace black, acetylene black, thermal carbon black, chimney black, graphite, and the like can be used.

In addition, the physical characteristics such as particle size, pore volume, and specific surface area of carbon black are not particularly limited. Various carbon blacks used in the rubber industry, such as SAF (Super Abrasion Furnace), ISAF, can be appropriately used. (Intermediate Super Abrasion Furnace), HAF (High Abrasion Furnace), FEF (Fast Extruding Furnace), GPF (General Purpose Furnace), SRF (Semi-Reinforcing Furnace, semi-reinforcing furnace, semi-reinforcing furnace, semi-reinforcing furnace, semi-reinforcing furnace) (both are abbreviations of carbon black classified by the American ASTM standard D-1765-82a) and so on.

When carbon black is used, its content is preferably 5 to 80 parts by mass, and more preferably 10 to 60 parts by mass based on 100 parts by mass of the rubber component. In addition, it may be 30 to 80 parts by mass, or 40 to 60 parts by mass. If it is such a compounding quantity, the effect as a reinforcing agent can be acquired well in the crosslinked rubber obtained by cross-linking an uncrosslinked rubber composition.

As the silicon dioxide, those that have been used as a reinforcing agent for rubbers can be used without particular limitation. Examples of the silicon dioxide include dry-type white carbon, wet-type white carbon, synthetic silicate-based white carbon, colloidal silicon dioxide, and precipitated silicon dioxide. The specific surface area of silicon dioxide is not particularly limited, and a range of usually 40 to 600 m ² / g, preferably 70 to 300 m ² / g can be used, and a primary particle size of 10 to 1000 nm can be used.

When using silicon dioxide, the blending amount is preferably 0.1 to 150 parts by mass, more preferably 10 to 100 parts by mass, and even more preferably 30 to 100 parts by mass, relative to 100 parts by mass of the rubber component.

In addition, for the purpose of formulating silica, a silane coupling agent can be blended in the uncrosslinked rubber composition. Examples of the silane coupling agent include vinyltrichlorosilane, vinyltriethoxysilane, vinyltri (β-methoxy-ethoxy) silane, and β- (3,4-epoxycyclohexyl). ) -Ethyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane , Bis (3- (triethoxysilyl) propyl) tetrasulfide, bis (3- (triethoxysilyl) propyl) disulfide, and the like. These can be used alone or in combination of two or more.

The addition amount of the silane coupling agent can be appropriately changed according to the required blending amount of silicon dioxide, and is preferably 0.1 to 20 parts by mass relative to 100 parts by mass of the rubber component.

As the filler, powders of minerals such as clay and talc; carbonates such as magnesium carbonate and calcium carbonate; alumina hydrates such as aluminum hydroxide and the like can be used.

Examples of the rubber extender oil include aromatic oils, naphthenic oils, and paraffin oils that have been used conventionally. The compounding amount of the rubber extender oil is preferably 0 to 100 parts by mass relative to 100 parts by mass of the rubber component.

Examples of the softener include botanic softeners such as tall oil, pine tar, rapeseed oil, cottonseed oil, peanut oil, castor oil, palm oil, and ointment, which are mainly linoleic acid, oleic acid, and abietic acid; Paraffin-based oils, naphthenic oils, aromatic oils, phthalic acid derivatives such as dibutyl phthalate, and the like. The blending amount of the softening agent is preferably 0 to 50 parts by mass based on 100 parts by mass of the rubber component.

The non-crosslinked rubber composition of the present embodiment may optionally contain various additives used in the field of the rubber industry, such as anti-aging agents, sulfur, cross-linking agents, vulcanization accelerators, vulcanization assistants, vulcanization delay agents, plastification One or two or more of additives, processing oils, plasticizers, etc. The amount of these additives is preferably 0.1 to 10 parts by mass based on 100 parts by mass of the rubber component.

The vulcanization accelerator or the vulcanization assistant is not particularly limited, and can be appropriately selected and used according to the rubber component and the crosslinking agent contained in the rubber composition. Furthermore, "vulcanization" means crosslinking via at least one sulfur atom.

Examples of the vulcanization accelerator include thiuram-based accelerators such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, and tetraethylthiuram disulfide; 2-mercaptobenzothiazole, Thiazole-based accelerators such as dibenzothiazole disulfide; sulphenimidines such as N-cyclohexyl-2-benzothiazylsulfenamide, and N-oxydiethyl-2-benzothiazolesulfenamides Accelerators; Guanidine accelerators such as diphenylguanidine and di-o-tolylguanidine; aldehyde-amine accelerators such as n-butyraldehyde-aniline condensation products, butyraldehyde-monobutylamine condensation products; hexamethylenetetramine, etc. Aldehyde-ammonia-based accelerators; thiourea-based accelerators such as symmetric diphenylthiourea.

When these vulcanization accelerators are blended, one type may be used alone, or two or more types may be used in combination. The compounding amount of the vulcanization accelerator is preferably 0.1 to 10 parts by mass based on 100 parts by mass of the rubber component.

Examples of the vulcanization aid include metal oxides such as zinc oxide (zinc white) and magnesium oxide; metal hydroxides such as calcium hydroxide; metal carbonates such as zinc carbonate and basic zinc carbonate; stearic acid, oleic acid, and the like Fatty acids; fatty metal salts such as zinc stearate and magnesium stearate; amines such as di-n-butylamine and dicyclohexylamine; ethylene glycol dimethacrylate, diallyl phthalate, N, N-m-phenylene dimaleimide, triallyl isocyanurate, trimethylolpropane trimethacrylate and the like.

In the case of blending these vulcanization assistants, one kind may be used alone, or two or more kinds may be used in combination. The blending amount of the vulcanization aid is preferably 0.1 to 10 parts by mass based on 100 parts by mass of the rubber component.

The non-crosslinked rubber composition according to this embodiment can be produced by applying a method generally used as a method for producing an uncrosslinked rubber composition. For example, it can manufacture by mixing each said component using a kneading machine, such as a Brinell mixer, a Banbury mixer, and a roll mixer.

＜ crosslinked rubber ＞
The crosslinked rubber of this embodiment is obtained by crosslinking the above-mentioned uncrosslinked rubber composition. Such a crosslinked rubber is useful as a rubber material for a tire, for example. Specifically, for example, if the crosslinked rubber of this embodiment is used for a tread portion of a tire, it can exhibit good rolling resistance characteristics and excellent wet grip performance.

The crosslinked rubber of the present embodiment can be produced by the same method as the method generally used as a crosslinking method of rubber, using the aforementioned uncrosslinked rubber composition. For example, a crosslinked rubber having a structure in which a rubber component is crosslinked can be obtained by heat-molding the above-mentioned uncrosslinked rubber composition and forming it into a desired shape.

The crosslinked rubber of this embodiment can be preferably used for various applications. For example, it can be preferably used in tires, adhesives, films, medical tapes, coatings, inks, asphalt adhesives, cloths, waterproofing agents, printer resins, etc., and can be particularly preferably used in tire applications (especially applications On the tire face).

＜ tires ＞
The tire of this embodiment contains the above-mentioned crosslinked rubber.

The tire of this embodiment preferably contains the above-mentioned crosslinked rubber in the tread portion. Such a tire can significantly exhibit good rolling resistance characteristics and excellent wet grip performance.

The tire of this embodiment may have the same configuration as a conventionally known tire except that the above-mentioned crosslinked rubber is applied to at least a part of the tire.

As mentioned above, although the preferred embodiment of this invention was described, this invention is not limited to the said embodiment. For example, the present invention may also be a method of imparting good rolling resistance characteristics and excellent wet grip performance to a rubber material by adding the aforementioned rubber additive to a rubber component used in a tire. In this case, in the previous method of improving the rubber material, it is difficult to have both good rolling resistance characteristics and excellent wet grip performance. However, as wet grip improves, rolling resistance characteristics decrease. The method of the present invention can impart good rolling resistance characteristics and excellent wet grip performance to rubber materials.
Examples

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

(Hydrogenated petroleum resin 1)
＜ Synthesis of unsaturated hydrocarbon polymer ＞
The components shown in Table 1 were prepared and mixed at the mass ratios shown in Table 1 to obtain a mixed solution. Then, the obtained mixed solution was put into a thermal polymerization apparatus (manufactured by Toyo High Pressure Co., Ltd.). Next, the mixed solution was heated to 276 ° C. under a condition of a temperature increase rate of 5 ° C./min, and maintained for 120 minutes. Thereafter, cooling water was flowed in and quenched to obtain a thermally polymerized resin solution. Then, the thermally polymerized resin solution was subjected to light component removal (distillation) to remove unreacted materials and components having a low degree of polymerization, thereby obtaining a polymer having a softening point of 85 ° C.

<Hydrogenation of polymers of unsaturated hydrocarbons>
The polymer of the obtained unsaturated hydrocarbon was adjusted to a concentration of 30% by mass in kerosene and melted. The obtained solution was put into a hydrogenation reactor filled with a nickel-based catalyst, while hydrogen was allowed to flow, and the hydrogenation of the unsaturated hydrocarbon polymer was performed under the conditions of a pressure of 18 MPa and a temperature of 280 ° C to obtain an unsaturated hydrocarbon-containing polymer. Solution of polymer hydride. The obtained hydride solution of the polymer containing an unsaturated hydrocarbon was subjected to light component removal (distillation), and kerosene in the solution was removed to obtain a hydrogenated petroleum resin 1.

<Physical property evaluation of hydrogenated petroleum resin>
[Determination of softening point]
The softening point of the obtained hydrogenated petroleum resin sample was measured. The softening point was measured using a DP70 from Mettler-Toledo, and measured by a method according to ASTM D6090. The results are shown in Table 1.

[Determination of aromatic content]
The aromatic content of the obtained hydrogenated petroleum resin sample was measured. Determination of the content of aromatic hydrogenated petroleum-based resin of the number of hydrogen bonded to the aromatic ring of (M ₂₎ with respect to the entire amount of hydrogen (M ₁₎ a ratio (M ₂ / M _1), the ratio (M ₂ / M ₁ ) is calculated as a percentage. The results are shown in Table 1.

[Measurement of weight average molecular weight]
The weight average molecular weight of the obtained hydrogenated petroleum resin sample was measured. The weight average molecular weight is measured by GPC (gel permeation chromatography), and is a value obtained by standard polystyrene conversion. The results are shown in Table 1.

(Hydrogenated petroleum resins 2 and 5)
＜ Synthesis of unsaturated hydrocarbon polymer ＞
A polymer of an unsaturated hydrocarbon was obtained in the same manner as in the hydrogenated petroleum resin 1 except that the raw material components were changed as shown in Table 1.

<Hydrogenation of polymers of unsaturated hydrocarbons>
The hydrogenation of the polymer of the unsaturated hydrocarbon was performed in the same manner as the hydrogenated petroleum resin 1 except that the temperature of hydrogenation of the polymer of the unsaturated hydrocarbon was set to 240 ° C to obtain a hydrogenated petroleum resin. The physical properties of the obtained hydrogenated petroleum resin were evaluated in the same manner as in the hydrogenated petroleum resin 1. The results are shown in Table 1.

(Hydrogenated petroleum resins 3, 4 and 6)
＜ Synthesis of unsaturated hydrocarbon polymer ＞
A polymer of an unsaturated hydrocarbon was obtained in the same manner as in the hydrogenated petroleum resin 1 except that the raw material components were changed as shown in Table 1.

<Hydrogenation of polymers of unsaturated hydrocarbons>
Hydrogenation of a polymer of an unsaturated hydrocarbon is performed in the same manner as in the hydrogenated petroleum resin 1, thereby obtaining a hydrogenated petroleum resin. The physical properties of the obtained hydrogenated petroleum resin were evaluated in the same manner as in the hydrogenated petroleum resin 1. The results are shown in Table 1.

[Table 1]

(Examples 1 to 3 and Comparative Example 1)
＜ Production of uncrosslinked rubber composition ＞
The components shown in Table 2 were prepared and kneaded at the mass ratio shown in Table 2 to obtain an uncrosslinked rubber composition. Hydrogenated petroleum resin 1 was used in Example 1, hydrogenated petroleum resin 2 was used in Example 2, hydrogenated petroleum resin 3 was used in Example 3, and hydrogenated petroleum resin 6 was used in Comparative Example 1. The kneading department used Laboplastomill (manufactured by Toyo Seiki Co., Ltd.) and a rolling machine (manufactured by KNEADER MACHINERY). The kneading conditions were set to a starting temperature of 130 ° C, a rotation speed of 50 rpm, and a kneading time of 9 minutes.

[Table 2]

Details of the components in Table 2 are as follows.
[Rubber composition]
SBR: Buna FX3234A-2HM (trade name), manufactured by LANXESS, styrene-butadiene rubber. Furthermore, Buna FX3234A-2HM is an oil-filled product. The value of SBR in Table 2 represents the actual SBR blending amount contained in Buna FX3234A-2HM, and the value of oil in Table 2 represents the content contained in Buna FX3234A-2HM. The actual amount of oil blended.
BR: UBEPOL BR150L (trade name), manufactured by Ube Industries, butadiene rubber
[Filling material]
Silicon dioxide: ULTRASIL VN3 (trade name), manufactured by Evonik
[Silane coupling agent]
Si75: Trade name, manufactured by Evonik
[Vulcanization accelerator]
Nocceler D: Trade name, manufactured by Onai Shinko Chemical Industry Co., Ltd.
Nocceler CZ: Trade name, manufactured by Onai Shinko Chemical Co., Ltd. Zinc oxide: manufactured by Hakusui Tech, stearic acid: manufactured by Nippon Oil Co., Ltd.
[Anti-aging agent]
Nocrac 6C: Trade name, manufactured by Onai Shinko Chemical Industry Co., Ltd.
Sunnoc: Trade name, manufactured by Onai
[Vulcanizing agent]
Sulfur: HK200-5 (trade name), manufactured by Hosei Chemical Industry Co., Ltd.

＜ Production of Crosslinked Rubber ＞
The uncrosslinked rubber composition obtained by kneading was subjected to thermoforming using a press (manufactured by Dumbbell) to produce a sheet-shaped crosslinked rubber. The conditions for the thermoforming were 160 ° C and 20 minutes, and the thermoforming was performed so that the thickness of the sheet became 2 mm.

＜ Viscoelasticity measurement ＞
From the produced sheet-shaped crosslinked rubber, a sample was punched with a thickness of 2 mm × width 5 mm × length 50 mm. Then, a viscoelasticity measurement was performed using the punched sample. The conditions for measuring viscoelasticity were measured in a tensile mode at a frequency of 10 Hz and a strain of 0.1%, while heating at a temperature of 2 ° C / min in a temperature range of -80 ° C to 80 ° C. The device used is DMA + 1000 manufactured by Metravib.

The frequency here is 10 Hz. The reason is that if the time-temperature exchange algorithm of viscoelasticity is used, the wet grip performance is related to the tanδ value at 10 Hz and 0 ° C. It is known that the larger the value, the wet grip The better the ground. In addition, the rolling resistance is similarly related to the tan δ value at 10 Hz and 60 ° C. It is known that the smaller the value, the better the rolling resistance characteristic. The results are shown in Table 3. Furthermore, regarding the tan δ value (relative value with respect to Comparative Example 1) at 0 ° C in Table 3, the larger the value, the better the wet grip. Regarding the tan δ value (relative value with respect to Comparative Example 1) at 60 ° C in Table 3, the larger the value, the better the rolling resistance characteristics.

[table 3]

(Examples 4 to 6 and Comparative Example 2)
＜ Production of uncrosslinked rubber composition ＞
As the hydrogenated petroleum resin, hydrogenated petroleum resin 4 was used in Example 4, hydrogenated petroleum resin 5 was used in Example 5, hydrogenated petroleum resin 3 was used in Example 6, and hydrogenated petroleum resin 6 was used in Comparative Example 2. Except the following as SBR, an uncrosslinked rubber composition was obtained in the same manner as in Example 1.

SBR: NS522 (trade name), manufactured by Zeon Corporation of Japan, styrene-butadiene rubber. Furthermore, NS522 is an oil-filled product. The value of SBR in Table 2 represents the substantial SBR blending amount contained in NS522, and the value of oil in Table 2 represents the substantial blending amount of oil contained in NS522.

＜ Production of Crosslinked Rubber ＞
A sheet-shaped crosslinked rubber was produced in the same manner as in Example 1, and the viscoelasticity was measured. The results are shown in Table 4. Furthermore, regarding the tan δ value (relative value with respect to Comparative Example 2) of 0 ° C in Table 4, the larger the value, the better the wet grip. Regarding the value of tan δ at 60 ° C in Table 4 (relative value with respect to Comparative Example 2), the larger the value, the better the rolling resistance characteristics.

[Table 4]

Claims (10)

An additive for rubber comprising a hydrogenated petroleum resin as a hydride of a polymer of an unsaturated hydrocarbon, The unsaturated hydrocarbon contains an aromatic compound having an aromatic ring and an alicyclic compound having a five-membered ring, The aromatic compound contains an indene compound having an indene skeleton, and The content of the indene compound is 15 to 60% by mass based on the total amount of the unsaturated hydrocarbons. The additive for rubber according to claim 1, wherein the alicyclic compound contains a DCPD-based compound having a dicyclopentadiene skeleton. For example, the rubber additive of claim 1 or 2, wherein the content of the alicyclic compound is 40 to 85% by mass based on the total amount of the unsaturated hydrocarbons. The rubber additive according to any one of claims 1 to 3, wherein a ratio of the indene compound to the aromatic compound is 50% by mass or more. The additive for rubber according to any one of claims 1 to 4, wherein the aromatic content in the hydrogenated petroleum resin is 0.3 to 30%. The rubber additive according to any one of claims 1 to 5, wherein the softening point of the hydrogenated petroleum resin is 80 to 150 ° C. The rubber additive according to any one of claims 1 to 6, wherein the weight average molecular weight of the hydrogenated petroleum resin is 200 to 1,000. An uncrosslinked rubber composition containing a rubber component, the rubber additive according to any one of claims 1 to 7, and a crosslinking agent. A crosslinked rubber obtained by crosslinking an uncrosslinked rubber composition as claimed in claim 8. A tire comprising a crosslinked rubber as claimed in claim 9 in a tread portion.