Hydrogenated petroleum resin, rubber additive, uncrosslinked rubber composition, crosslinked rubber, and tire

Abstract

A hydrogenated petroleum resin that is a hydrogenation product of a C9 petroleum resin, wherein the ratio (M2 / M1) of the total number (M2) of hydrogen atoms bound to the aromatic ring in the hydrogenated petroleum resin to the total number (M1) of hydrogen atoms in the hydrogenated petroleum resin is between 0.15 and 0.45 inclusive.

Description

Hydrogenated petroleum resins, rubber additives, uncrosslinked rubber compositions, crosslinked rubber and tires

[0001] The present invention relates to a hydrogenated petroleum resin, a rubber additive, an uncrosslinked rubber composition, a crosslinked rubber, and a tire.

[0002] BACKGROUND ART Various additives have been used as rubber additives for imparting various properties to rubber components.

[0003] For example, Patent Document 1 discloses a rubber composition in which a rubber matrix containing a diene rubber and a high molecular weight modified conjugated diene polymer is blended with a hydrogenated resin, a low molecular weight modified conjugated diene polymer, and a reinforcing filler.

[0004] JP 2011-88988 A

[0005] When a rubber additive has good compatibility with the rubber component, it is expected to impart more uniform and efficient properties.

[0006] Therefore, an object of the present invention is to provide a hydrogenated petroleum resin which has high compatibility with rubber components, good color, and is suitable as a rubber additive.

[0007] In recent years, tires have been strongly required to have good rolling resistance characteristics from the viewpoint of improving fuel economy. On the other hand, tires have been strongly required to have good wet grip performance from the viewpoint of safety. However, it is difficult to achieve both good rolling resistance characteristics and good wet grip performance.

[0008] Therefore, an object of the present invention is to provide a hydrogenated petroleum resin that can impart good rolling resistance and excellent wet grip performance to a crosslinked rubber. Another object of the present invention is to provide a rubber additive containing the hydrogenated petroleum resin, 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 in the tread portion.

[0009] One aspect of the present invention is a hydrogenated petroleum resin that is a hydrogenated product of a C9 petroleum resin, wherein the total number of hydrogen atoms in the hydrogenated petroleum resin (M １ ) relative to the total number of hydrogen atoms bonded to the aromatic rings in the hydrogenated petroleum resin (M２ ) ratio (M ２ / M １ ) is 0.15 to 0.45.

[0010] In one embodiment, the ratio (M ２ / M １ ) may be 0.2 to 0.4.

[0011] The softening point of the hydrogenated petroleum resin according to one embodiment may be 70 to 200°C.

[0012] The hydrogenated petroleum resin according to one embodiment may have an iodine value of 20 or less.

[0013] Another aspect of the present invention relates to a rubber additive comprising the hydrogenated petroleum resin.

[0014] Yet another aspect of the present invention relates to an uncrosslinked rubber composition containing a rubber component, the rubber additive, and a crosslinking agent.

[0015] Yet another aspect of the present invention relates to a crosslinked rubber obtained by crosslinking the uncrosslinked rubber composition.

[0016] Yet another aspect of the present invention relates to a tire containing the above crosslinked rubber in a tread portion.

[0017] According to the present invention, there is provided a hydrogenated petroleum resin having high compatibility and good color. Furthermore, according to the present invention, there is provided a hydrogenated petroleum resin that can impart good rolling resistance characteristics and excellent wet grip performance to a crosslinked rubber. Furthermore, according to the present invention, there are provided a rubber additive containing the hydrogenated petroleum resin, 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 in the tread portion.

[0018] Preferred embodiments of the present invention will be described in detail below.

[0019] <Hydrogenated Petroleum Resin> The hydrogenated petroleum resin of this embodiment is a hydrogenated product (also referred to as a partially hydrogenated product) of a C9 petroleum resin. In this embodiment, the total number of hydrogen atoms in the hydrogenated petroleum resin (M １ ) relative to the total number of hydrogen atoms bonded to the aromatic rings in the hydrogenated petroleum resin (M ２ ) ratio (M２ / M １ ) is 0.15 to 0.45.

[0020] In this specification, the ratio (M ２ / M １ ) is a hydrogenated petroleum resin １ It is determined by H-NMR measurement. That is, the ratio (M ２ / M １ ) is a hydrogenated petroleum resin １ The sum of the peak areas of the peaks representing hydrogen atoms in the hydrogenated petroleum resin in the H-NMR spectrum (S １ ) the sum of the peak areas of the peaks representing hydrogen atoms bonded to aromatic rings in the hydrogenated petroleum resin (S ２ ) ratio (S ２ / S １ ) can also be said.

[0021] Ratio (M ２ / M １ ) can be said to be an index representing the aromatic content (content ratio of aromatic rings) in the hydrogenated petroleum resin. That is, the hydrogenated petroleum resin of this embodiment is a C9 petroleum resin having a ratio (M ２ / M １ ) is in the range of 0.15 to 0.45. In addition, the ratio in a C9 petroleum resin is usually about 0.45. That is, the hydrogenated petroleum resin in this embodiment is a product obtained by hydrogenating the petroleum resin so that the ratio (M ２ / M １ It can be said that the hydrogenated product is a product obtained by intentionally leaving the aromatic rings so that the ratio (R) of the aromatic rings to the aromatic rings is 0.15 or more.

[0022] The hydrogenated petroleum resin of this embodiment has a ratio (M ２ / M １ In other words, the hydrogenated petroleum resin of this embodiment can be said to have a good hue by sufficiently suppressing yellowing through hydrogenation of the ethylenically unsaturated bonds, while having a high compatibility due to the presence of the aromatic rings.

[0023] Furthermore, the hydrogenated petroleum resin of this embodiment can impart good rolling resistance properties and excellent wet grip performance to rubber materials, and therefore the hydrogenated petroleum resin of this embodiment can be suitably used as a rubber additive (more preferably, a rubber additive for tires).

[0024] With regard to rolling resistance characteristics, it is known that the smaller the loss factor (tan δ) measured at a frequency of 10 Hz and near 60°C in a 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 larger the loss factor (tan δ) measured at a frequency of 10 Hz and near 0°C in a dynamic viscoelasticity test of a rubber material, the better the wet grip performance.

[0025] Both rolling resistance and wet grip performance are properties related to the hysteresis loss of rubber materials. Generally, increasing hysteresis loss increases grip and braking performance, but also increases rolling resistance, resulting in poor fuel economy. As such, grip performance and rolling resistance are in a contradictory relationship, making it difficult to simultaneously achieve good rolling resistance and excellent wet grip performance.

[0026] By adding the hydrogenated petroleum resin of this embodiment to a rubber material, the loss factor (tan δ) at a low temperature (e.g., 0°C) can be increased while maintaining a low loss factor (tan δ) at a high temperature (e.g., 60°C) in a dynamic viscoelasticity test. This makes it possible to impart good rolling resistance characteristics and excellent wet grip performance to the rubber material.

[0027] The inventors believe that the mechanism by which the above-mentioned effects are achieved is as follows. Generally, the peak of the loss factor (tan δ) of rubber is in a temperature range below 0°C. It is known that the softening point of petroleum resin is usually higher than the glass transition temperature (Tg) of rubber. Therefore, by adding petroleum resin to a rubber material, the peak of the loss factor (tan δ) can be shifted to a higher temperature side, and the loss factor (tan δ) at around 0°C can be increased.

[0028] In general petroleum resins, the ethylenically unsaturated bonds in the petroleum resin react with the crosslinking agent, resulting in crosslinking between the rubber component and the petroleum resin, or the ethylenically unsaturated bonds consume the crosslinking agent, resulting in insufficient crosslinking of the rubber component, which is thought to result in an insufficient peak shift of the loss factor (tan δ).In contrast, in this embodiment, a hydrogenated C9 petroleum resin is used, and therefore the ethylenically unsaturated bonds are reduced by hydrogenation, making these problems less likely to occur, and it is thought that the peak of the loss factor (tan δ) can be efficiently shifted to the high temperature side.

[0029] In this embodiment, the hydrogenated petroleum resin has sufficient aromatic rings remaining to improve its compatibility with the rubber component. This improvement in compatibility is thought to result in a sharper peak in the loss factor (tan δ), and to keep the loss factor (tan δ) at around 60°C low.

[0030] The hydrogenated petroleum resin of this embodiment can also impart excellent dry grip performance to rubber materials. Since dry grip performance is a property required for sports tires, racing tires, etc., the hydrogenated petroleum resin of this embodiment can be suitably used as a rubber additive for sports tires, racing tires, etc.

[0031] It is known that in a dynamic viscoelasticity test of a rubber material, the larger the loss factor (tan δ) measured at a frequency of 10 Hz and around 20° C., the better the dry grip performance. By adding the hydrogenated petroleum resin of this embodiment to a rubber material, the loss factor (tan δ) at room temperature (e.g., 20° C.) can be increased while maintaining a low loss factor (tan δ) at high temperatures (e.g., 60° C.) in the dynamic viscoelasticity test, and therefore good rolling resistance characteristics and excellent dry grip performance can be imparted to the rubber material.

[0032] Hereinafter, the hydrogenated petroleum resin of this embodiment (hereinafter also simply referred to as hydrogenated petroleum resin) will be described in detail.

[0033] The hydrogenated petroleum resin is a hydrogenated product of a C9 petroleum resin. As described above, the hydrogenated petroleum resin has a ratio (M ２ / M １) is 0.15 or more, it can also be said to be a partially hydrogenated C9 petroleum resin.

[0034] The C9 petroleum resin may be a solidified C9 fraction extracted through thermal cracking of petroleum-derived feedstock oil, or a solidified mixture of the C9 fraction and other hydrocarbons (wherein the C9 fraction is 90% by mass or more, preferably 95% by mass or more). The C9 fraction is a fraction containing primarily hydrocarbons having 9 carbon atoms (for example, 60% by mass or more, preferably 80% by mass or more), and may further contain components other than hydrocarbons having 9 carbon atoms (for example, hydrocarbons having 8 or 10 carbon atoms (styrene, methylindene, etc.)).

[0035] The C9 fraction may be, for example, a C9 fraction obtained during the thermal cracking of petroleum naphtha.

[0036] The C9 fraction may contain, for example, saturated and unsaturated components. Examples of saturated components include propylbenzene, methylethylbenzene, and indane. Examples of unsaturated components include styrene, methylstyrene, vinyltoluene, dicyclopentadiene, indene, and methylindene.

[0037] The method for producing the C9 petroleum resin is not particularly limited, and may be a known method. The C9 petroleum resin can be produced, for example, by the following method. First, 0.01 to 5 parts by mass of a Lewis acid catalyst is used per 100 parts by mass of the C9 fraction, and polymerization is carried out at a temperature of 0 to 60°C. Next, 0.1 to 20 parts by mass of a basic substance is added to the reaction system, and a neutralization reaction is carried out at a temperature of 10 to 100°C. After the neutralization reaction, the mixture is washed with water as necessary, and then 0.1 to 20 parts by mass of activated clay is added, and a clay treatment is carried out at a temperature of 10 to 100°C. After the clay treatment, the clay is filtered off, and unreacted components are removed by distillation to obtain a C9 petroleum resin.

[0038] The total number of hydrogen atoms in the C9 petroleum resin (M ３ ) relative to the total number of hydrogen atoms bonded to the aromatic ring in the C9 petroleum resin (M ４ ) ratio (M ４ / M ３ ) is not particularly limited, and the ratio (M ２ / M １ ) can be in the above range. ４ / M ３ ) may be, for example, 0.2 to 0.5, preferably 0.3 to 0.5, and more preferably 0.4 to 0.5.

[0039] In addition, the ratio (M ４ / M ３ ) is a C9 petroleum resin １ It is determined by H-NMR measurement. That is, the ratio (M ４ / M ３ ) is a C9 petroleum resin １ The sum of the peak areas of the peaks representing hydrogen atoms in the C9 petroleum resin in the H-NMR spectrum (S ３ ) the sum of the peak areas of the peaks representing hydrogen atoms bonded to aromatic rings in the C9 petroleum resin (S ４ ) ratio (S ４ / S ３ ) can also be said.

[0040] The softening point of the C9 petroleum resin may be, for example, 200 ° C or less, preferably 170 ° C or less, and may be 160 ° C or less, 150 ° C or less, or 140 ° C or less. The softening point of the C9 petroleum resin may be, for example, 70 ° C or more, preferably 80 ° C or more, and more preferably 90 ° C or more. This makes it easier to obtain a hydrogenated petroleum resin having a suitable softening point as described below. That is, the softening point of the C9 petroleum resin may be, for example, 70 to 200 ° C, 70 to 170 ° C, 70 to 160 ° C, 70 to 150 ° C, 70 to 140 ° C, 80 to 200 ° C, 80 to 170 ° C, 80 to 160 ° C, 80 to 150 ° C, 80 to 140 ° C, 90 to 200 ° C, 90 to 170 ° C, 90 to 160 ° C, 90 to 150 ° C, or 90 to 140 ° C.

[0041] The softening point in this specification refers to a value measured by a method in accordance with ASTM D6090.

[0042] The iodine value of the C9 petroleum resin is not particularly limited, but may be, for example, 25 or more, 30 or more, or 40 or more. In addition, the iodine value of the C9 petroleum resin is not particularly limited, but may be, for example, 100 or less, or 80 or less. That is, the iodine value of the C9 petroleum resin may be, for example, 25 to 100, 25 to 80, 30 to 100, 30 to 80, 40 to 100, or 40 to 80.

[0043] The iodine value in this specification refers to a value measured in accordance with JIS K 0070:1992.

[0044] The hydrogenation method of the C9 petroleum resin is not particularly limited, and may be carried out by a known method. For example, the hydrogenation of the C9 petroleum resin may be carried out by contacting the C9 petroleum resin with a hydrogenation catalyst in the presence of molecular hydrogen.

[0045] The hydrogenation catalyst is not particularly limited, and may be, for example, a nickel-based catalyst, a palladium-based catalyst, a platinum-based catalyst, or the like.

[0046] The hydrogenation conditions are not particularly limited, and a suitable ratio (M ２ / M １ The hydrogen pressure during hydrogenation may be, for example, 2 to 30 MPa, and the reaction temperature during hydrogenation may be, for example, 200 to 310°C.

[0047] The C9 petroleum resin may be dissolved in a solvent and brought into contact with the hydrogenation catalyst. The solvent may be any solvent that can dissolve the C9 petroleum resin and does not adversely affect the hydrogenation. Examples of the solvent that can be used include kerosene and methylcyclohexane. One type of solvent may be used alone, or two or more types may be used in combination.

[0048] Hydrogenated petroleum resin ratio (M ２ / M １ ) is 0.15 or more, preferably 0.17 or more, more preferably 0.19 or more, and even more preferably 0.2 or more. This further improves compatibility with the resin, and the above-mentioned effects are more pronounced. In addition, the ratio (M ２ / M １) is 0.45 or less, and may be 0.43 or less, 0.4 or less, or 0.38 or less. That is, the ratio (M ２ / M １ ) may be, for example, 0.15 to 0.45, 0.15 to 0.43, 0.15 to 0.4, 0.15 to 0.38, 0.17 to 0.45, 0.17 to 0.43, 0.17 to 0.4, 0.17 to 0.38, 0.19 to 0.45, 0.19 to 0.43, 0.19 to 0.4, 0.19 to 0.38, 0.2 to 0.45, 0.2 to 0.43, 0.2 to 0.4, or 0.2 to 0.38.

[0049] The iodine value of hydrogenated petroleum resin is lower than that of C9 petroleum resin. １ ) of hydrogenated petroleum resin relative to the iodine value (I ２ ) ratio (I ２ / I １ ) is, for example, 0.6 or less, preferably 0.5 or less, more preferably 0.4 or less, and may be 0.

[0050] The iodine value of the hydrogenated petroleum resin is not particularly limited, but is, for example, 20 or less, preferably 18 or less, more preferably 17 or less, and even more preferably 16 or less, and may be 15 or less. This sufficiently suppresses the adverse effects of the presence of ethylenically unsaturated bonds, and the above-mentioned effects are more significantly achieved. There is no particular limitation on the lower limit of the iodine value of the hydrogenated petroleum resin, and for example, the iodine value of the hydrogenated petroleum resin may be 0 or more, 1 or more, 2 or more, or 3 or more. That is, the iodine value of the hydrogenated petroleum resin may be, for example, 0 to 20, 0 to 18, 0 to 17, 0 to 16, 0 to 15, 1 to 20, 1 to 18, 1 to 17, 1 to 16, 1 to 15, 2 to 20, 2 to 18, 2 to 17, 2 to 16, 2 to 15, 3 to 20, 3 to 18, 3 to 17, 3 to 16, or 3 to 15. The iodine value of a hydrogenated petroleum resin can be said to be an index showing the amount of ethylenically unsaturated bonds in the hydrogenated petroleum resin. The ethylenically unsaturated bonds in the hydrogenated petroleum resin include ethylenically unsaturated bonds that were not hydrogenated during hydrogenation and ethylenically unsaturated bonds that were generated by hydrogenating part of the aromatic ring during hydrogenation.

[0051] The softening point of the hydrogenated petroleum resin may be, for example, 70°C or higher, preferably 80°C or higher, and more preferably 90°C or higher. When the softening point of the hydrogenated petroleum resin is high, the peak of the loss factor (tan δ) shifts to a higher temperature side, making it easier to obtain better wet grip performance. Furthermore, the softening point of the hydrogenated petroleum resin may be, for example, 200°C or lower, preferably 170°C or lower, and may be 160°C or lower, 150°C or lower, or 140°C or lower. When the softening point of the hydrogenated petroleum resin is low, excessive peak shift of the loss factor (tan δ) is suppressed, making it easier to obtain better rolling resistance characteristics. That is, the softening point of the hydrogenated petroleum resin may be, for example, 70 to 200°C, 70 to 170°C, 70 to 160°C, 70 to 150°C, 70 to 140°C, 80 to 200°C, 80 to 170°C, 80 to 160°C, 80 to 150°C, 80 to 140°C, 90 to 200°C, 90 to 170°C, 90 to 160°C, 90 to 150°C, or 90 to 140°C.

[0052] The weight average molecular weight of the hydrogenated petroleum resin is not particularly limited and may be, for example, 4000 or less, 3500 or less, or 3000 or less. When the weight average molecular weight of the hydrogenated petroleum resin is small, the softening point tends to be low. Furthermore, the weight average molecular weight of the hydrogenated petroleum resin may be, for example, 700 or more, or 1000 or more. When the weight average molecular weight of the hydrogenated petroleum resin is large, the softening point tends to be high. That is, the weight average molecular weight of the hydrogenated petroleum resin may be, for example, 700 to 4000, 700 to 3500, 700 to 3000, 1000 to 4000, 1000 to 3500, or 1000 to 3000.

[0053] The weight average molecular weight of the hydrogenated petroleum resin is a value measured by GPC (gel permeation chromatography) and converted into standard polystyrene.

[0054] The hydrogenated petroleum resin of this embodiment can be suitably used for applications such as additives for rubber, additives for plastics, additives for films, and adhesives.

[0055] <Rubber Additive> The rubber additive of this embodiment includes the hydrogenated petroleum resin described above. The rubber additive of this embodiment can impart good rolling resistance properties and excellent wet grip performance to a rubber material.

[0056] The rubber additive of this embodiment may be an additive consisting of only hydrogenated petroleum resin, or may be an additive containing hydrogenated petroleum resin and other components. As the other components, any known rubber additive may be used without particular limitation. Examples of the other components include the components that may be contained in the uncrosslinked rubber composition described below.

[0057] The amount of the rubber additive of this embodiment added to the rubber component is not particularly limited, and the amount of hydrogenated petroleum resin added per 100 parts by mass of the rubber component is preferably an amount within the below-described preferred range.

[0058] The amount of hydrogenated petroleum resin added is preferably 1 part by mass or more, more preferably 3 parts by mass or more, per 100 parts by mass of the rubber component. This tends to further improve wet grip performance. The amount of hydrogenated petroleum resin added may be, for example, 40 parts by mass or less, preferably 30 parts by mass or less, per 100 parts by mass of the rubber component. This tends to improve rubber elasticity. That is, the amount of hydrogenated petroleum resin added may be, for example, 1 to 40 parts by mass, 1 to 30 parts by mass, 3 to 40 parts by mass, or 3 to 30 parts by mass, per 100 parts by mass of the rubber component.

[0059] The uncrosslinked rubber composition according to the present embodiment contains a rubber component, the rubber additive, and a crosslinking agent. The crosslinked rubber obtained by crosslinking the uncrosslinked rubber composition can exhibit good rolling resistance and excellent wet grip performance when used in the tread of a tire, for example.

[0060] The rubber component is not particularly limited, and known rubber components can be used without any particular limitation. As the rubber component, butadiene rubber (BR), styrene-butadiene rubber (SBR), and natural rubber (NR) are preferred from the viewpoints of strength, processability, cost, etc. One type of rubber component may be used alone, or two or more types may be used in combination.

[0061] The glass transition temperature (Tg) of the rubber component may be, for example, 0°C or lower, preferably -20°C or lower. The glass transition temperature (Tg) of the rubber component may be, for example, -120°C or higher, preferably -100°C or higher. That is, the Tg of the rubber component may be, for example, -120 to 0°C, -120 to -20°C, -100 to 0°C, or -100 to -20°C. In this specification, the glass transition temperature of the rubber component refers to a value measured by DSC (differential scanning calorimetry).

[0062] The crosslinking agent may be any of those commonly used for crosslinking rubber without any particular limitation, and may be appropriately selected depending on the rubber component. Examples of the crosslinking agent include sulfur crosslinking agents (e.g., sulfur, morpholine disulfide, alkylphenol disulfide, etc.), organic peroxide crosslinking agents, etc. One type of crosslinking agent may be used alone, or two or more types may be used in combination.

[0063] The content of the crosslinking agent is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 3 parts by mass, and even more preferably 1 to 2 parts by mass, per 100 parts by mass of the rubber component. That is, the content of the crosslinking agent may be, for example, 0.1 to 5 parts by mass, 0.1 to 3 parts by mass, 0.1 to 2 parts by mass, 0.5 to 5 parts by mass, 0.5 to 3 parts by mass, 0.5 to 2 parts by mass, 1 to 5 parts by mass, 1 to 3 parts by mass, or 1 to 2 parts by mass, per 100 parts by mass of the rubber component.

[0064] The uncrosslinked rubber composition according to the present embodiment may further contain various reinforcing agents, fillers, rubber extender oils, softeners, etc., which are used in the rubber industry. Each of these components may be used alone or in combination of two or more.

[0065] Examples of the reinforcing agent include carbon black and silica.

[0066] Carbon black is preferably used as a reinforcing agent because it has the effects of improving the abrasion resistance and rolling resistance properties of the crosslinked rubber, preventing cracks and crazes caused by ultraviolet rays (preventing ultraviolet degradation), etc. The type of carbon black is not particularly limited, and conventionally known carbon blacks can be used.

[0067] Furthermore, the physical properties of the carbon black, such as particle size, pore volume, and specific surface area, are not particularly limited, and various types of carbon black conventionally used in the rubber industry can be used as appropriate.

[0068] When carbon black is used, the content thereof is preferably 5 to 80 parts by mass, and more preferably 10 to 60 parts by mass, per 100 parts by mass of the rubber component. With such a blending amount, the effect as a reinforcing agent can be satisfactorily obtained in the crosslinked rubber obtained by crosslinking the uncrosslinked rubber composition.

[0069] As the silica, any silica that has been conventionally used as a reinforcing agent for rubber can be used without any particular limitation. The specific surface area of ​​the silica is not particularly limited, but is usually 40 to 600 m ２ / g, preferably 70 to 300 m ２ / g, and the primary particle diameter can be 10 to 1000 nm.

[0070] When silica is used, the compounding amount thereof is preferably 0.1 to 150 parts by mass, more preferably 10 to 130 parts by mass, and further preferably 30 to 110 parts by mass, per 100 parts by mass of the rubber component.

[0071] In addition, a silane coupling agent may be blended into the uncrosslinked rubber composition for the purpose of blending silica. As the silane coupling agent, any known silane coupling agent can be used without particular limitation. The silane coupling agents may be used alone or in combination of two or more.

[0072] The amount of the silane coupling agent added can be appropriately changed depending on the desired amount of silica to be compounded, but is preferably 0.1 to 20 parts by mass per 100 parts by mass of the rubber component.

[0073] As the filler, for example, mineral powders, carbonates, alumina hydrate, etc. can be used.

[0074] As the rubber extender oil, conventionally used aromatic oils, naphthenic oils, paraffinic oils, etc. The blending amount of the rubber extender oil is preferably 0 to 100 parts by mass per 100 parts by mass of the rubber component.

[0075] Examples of the softener include tall oil, vegetable oil, paraffin oil, naphthenic oil, aromatic oil, phthalic acid derivative, etc. The blending amount of the softener is preferably 0 to 50 parts by mass per 100 parts by mass of the rubber component.

[0076] The uncrosslinked rubber composition according to the present embodiment may further contain, as necessary, one or more of various additives used in the rubber industry, such as antioxidants, crosslinking agents, vulcanization accelerators, vulcanization aids, vulcanization retarders, peptizers, process oils, plasticizers, etc. The blending amount of these additives is preferably 0.1 to 10 parts by mass per 100 parts by mass of the rubber component.

[0077] The vulcanization accelerator and vulcanization aid are not particularly limited and can be appropriately selected and used depending on the rubber component and crosslinking agent contained in the rubber composition. Note that "vulcanization" refers to crosslinking via at least one sulfur atom.

[0078] Examples of the vulcanization accelerator include thiuram accelerators, thiazole accelerators, sulfenamide accelerators (e.g., N-cyclohexyl-2-benzothiazylsulfenamide), guanidine accelerators (e.g., diphenylguanidine), aldehyde-amine accelerators, and urea accelerators.

[0079] When these vulcanization accelerators are compounded, one kind may be used alone or two or more kinds may be used in combination. The compounding amount of the vulcanization accelerator is preferably 0.1 to 10 parts by mass per 100 parts by mass of the rubber component.

[0080] Examples of the vulcanization aid include metal oxides (for example, zinc oxide), metal hydroxides, metal carbonates, fatty acids (for example, stearic acid), and fatty acid metal salts.

[0081] When these vulcanization aids are compounded, one kind may be used alone, or two or more kinds may be used in combination. The compounding amount of the vulcanization aid is preferably 0.1 to 10 parts by mass per 100 parts by mass of the rubber component.

[0082] The uncrosslinked rubber composition according to the present embodiment can be produced by applying a method generally used for producing an uncrosslinked rubber composition, for example, by mixing the above-mentioned components using a kneader such as a Brabender mixer, a Banbury mixer, or a roll mixer.

[0083] <Crosslinked Rubber> The crosslinked rubber according to this embodiment is obtained by crosslinking the uncrosslinked rubber composition described above. Such a crosslinked rubber is useful, for example, as a rubber material for tires. Specifically, for example, when the crosslinked rubber according to this embodiment is used in the tread portion of a tire, good rolling resistance characteristics and excellent wet grip performance can be achieved.

[0084] The crosslinked rubber according to the present embodiment can be produced using the uncrosslinked rubber composition by a method similar to that used as a method for crosslinking rubber in general. For example, the uncrosslinked rubber composition can be molded into a desired shape by heat molding, thereby obtaining a crosslinked rubber having a structure in which the rubber component is crosslinked.

[0085] The crosslinked rubber according to this embodiment can be suitably used in various applications, such as tires, adhesives, films, medical tapes, paints, inks, asphalt binders, fabrics, waterproofing agents, and printer resins, and is particularly suitably used in tires (particularly in tire treads).

[0086] <Tire> The tire according to the present embodiment contains the above-described crosslinked rubber.

[0087] The tire according to the present embodiment preferably contains the above-described crosslinked rubber in the tread portion, and such a tire can remarkably exhibit good rolling resistance characteristics and excellent wet grip performance.

[0088] The tire according to the present embodiment may have the same configuration as a conventionally known tire, except that the above-described crosslinked rubber is used in at least a part thereof.

[0089] Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, the present invention may be a method for imparting good rolling resistance properties and excellent wet grip performance to a rubber material by adding the above-mentioned rubber additive to a rubber component used in a tire. In this case, conventional methods for improving rubber materials have had difficulty achieving both good rolling resistance properties and excellent wet grip performance, and the rolling resistance properties have decreased as the wet grip properties have improved. However, the method of the present invention can impart good rolling resistance properties and excellent wet grip performance to a rubber material.

[0090] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0091] (Production Example A1) 100 parts by mass of a C9 fraction shown in Table 1 obtained by cracking naphtha and 1.2 parts by mass of a boron trifluoride catalyst were charged into an autoclave and subjected to cationic polymerization for 1.5 hours to obtain a C9 petroleum resin A1 shown in Table 2. The composition of the unsaturated components involved in the polymerization reaction in the C9 fraction was as shown in Table 1 below.

[0092] (Production Examples A2 to A6) Cationic polymerization was carried out in the same manner as in Production Example 1, except that the polymerization time was adjusted as shown in Table 2, to obtain C9-based petroleum resins A2 to A6 shown in Table 2.

[0093]

[0094]

[0095] In Table 2, the color is evaluated by visual inspection, with C indicating significant coloration due to yellowing or the like, and A indicating almost no coloration due to yellowing or the like.

[0096] (Example B1) 50 g of C9-based petroleum resin A1, 110 g of diluent (methylcyclohexane), and 2 g of 0.5% platinum-supported catalyst were charged into a 0.2-liter autoclave, and a hydrogenation (hydrogenation) reaction was carried out at a hydrogen pressure of 3 MPaG and 250°C. The reaction solution was appropriately extracted, and the reaction was terminated when a predetermined iodine value was reached. After completion of the reaction, the diluent was removed by distillation to obtain hydrogenated petroleum resin B1. The softening point of the obtained hydrogenated petroleum resin B1 was 125°C, and the specific iodine value (M ２ / M １ ) was 0.33 and the iodine value was 13.

[0097] (Example B2) The same reaction as in Example B1 was carried out except that the hydrogen pressure was changed to 15 MPaG, to obtain hydrogenated petroleum resin B2. The softening point of the obtained hydrogenated petroleum resin B2 was 125°C, and the specific gravity (M ２ / M １ ) was 0.20 and the iodine value was 10.

[0098] (Example B3) The same reaction as in Example B1 was carried out, except that the C9-based petroleum resin A1 was changed to the C9-based petroleum resin A2, to obtain hydrogenated petroleum resin B3. The softening point of the obtained hydrogenated petroleum resin B3 was 105°C, and the ratio (M ２ / M １ ) was 0.35 and the iodine value was 4.

[0099] (Comparative Example b3) A hydrogenated petroleum resin b3 was obtained by carrying out the same reaction as in Example B1, except that the C9 petroleum resin A1 was replaced with the C9 petroleum resin A2, the catalyst was replaced with a nickel-synthetic silica alumina catalyst, the hydrogen pressure was changed to 20 MPaG, and the reaction temperature was changed to 280°C. The softening point of the obtained hydrogenated petroleum resin b3 was 105°C, and the specific (M ２ / M １ ) was 0.09 and the iodine value was 2.

[0100]

[0101] (Example B4) The same reaction as in Example B1 was carried out, except that the C9-based petroleum resin A1 was replaced with the C9-based petroleum resin A3 and the reaction temperature was changed to 300°C, to obtain hydrogenated petroleum resin B4. The softening point of the obtained hydrogenated petroleum resin B4 was 90°C, and the ratio (M ２ / M １ ) was 0.36 and the iodine value was 10.

[0102] (Example B5) The same reaction as in Example B1 was carried out, except that the C9-based petroleum resin A1 was replaced with the C9-based petroleum resin A4 and the reaction temperature was changed to 300°C, to obtain hydrogenated petroleum resin B5. The softening point of the obtained hydrogenated petroleum resin B5 was 130°C, and the ratio (M ２ / M １ ) was 0.37 and the iodine value was 15.

[0103] (Example B6) The same reaction as in Example B1 was carried out, except that the C9-based petroleum resin A1 was replaced with the C9-based petroleum resin A5 and the reaction temperature was changed to 300°C, to obtain hydrogenated petroleum resin B6. The softening point of the obtained hydrogenated petroleum resin B6 was 140°C, and the ratio (M ２ / M １ ) was 0.38 and the iodine value was 14.

[0104] (Example B7) The same reaction as in Example B1 was carried out, except that the C9-based petroleum resin A1 was changed to the C9-based petroleum resin A6, to obtain hydrogenated petroleum resin B7. The softening point of the obtained hydrogenated petroleum resin B7 was 165°C, and the ratio (M ２ / M １ ) was 0.38 and the iodine value was 10.

[0105]

[0106] In Tables 3 and 4, the color is evaluated by visual inspection, with C indicating significant coloration due to yellowing or the like, and A indicating almost no coloration due to yellowing or the like.

[0107] Furthermore, MACP (methylcyclohexane, aniline, cloud point measurement) and XDCP (m-xylene, diacetone alcohol, cloud point measurement) refer to values ​​measured by the following method. <MACP> 2 g of a sample is heated and dissolved in a solution containing 6 ml of methylcyclohexane and 6 ml of aniline. The temperature is gradually lowered while checking with a thermometer, and the temperature at which the thermometer becomes cloudy and no longer visible is taken as the MACP (°C). MACP is a parameter that indicates compatibility with polyolefins, with lower values ​​indicating higher compatibility. <XDCP> 2 g of a sample is heated and dissolved in a solution containing 7 ml of m-xylene and 5 ml of diacetone alcohol. The temperature is gradually lowered while checking with a thermometer, and the temperature at which the thermometer becomes cloudy and no longer visible is taken as the XDCP (°C). XDCP is a parameter that indicates compatibility with aromatic resins (such as polystyrene), with lower values ​​indicating higher compatibility.

[0108] (Example C1) The hydrogenated petroleum resin B1 of Example B1 was used as a rubber additive, and the following tests were carried out. <Production of Uncrosslinked Rubber Composition> The components shown in Table 5 below were kneaded in the proportions shown in Table 5 to obtain an uncrosslinked rubber composition. For kneading, a Laboplastomill (manufactured by Toyo Seiki Seisakusho) and a roller machine (manufactured by Kneader Machinery Co., Ltd.) were used, and the kneading conditions were a starting temperature of 135°C, a rotation speed of 50 rpm, and a kneading time of 8 minutes.

[0109]

[0110] The details of each component in Table 5 are as follows: [Rubber component] SBR: Tufden E-581 (product name), styrene-butadiene rubber, manufactured by Asahi Kasei Corporation. Tufden E-581 is an oil-extended product, and the SBR value in Table 5 indicates the net amount of SBR contained in Tufden E-581, and the oil value in Table 5 indicates the net amount of oil contained in Tufden E-581. BR: Nipol BR1220 (trade name), manufactured by Nippon Zeon Co., Ltd., butadiene rubber [Filler] Silica: Nipsil AQ (trade name), manufactured by Tosoh Corporation [Silane coupling agent] Si69: Cabras 4 (trade name), manufactured by Osaka Soda Co., Ltd. [Vulcanization accelerator] Noccela D (trade name): diphenyl guanidine, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Noccela CZ (trade name): N-cyclohexyl-2-benzothiazylsulfenamide, manufactured by Ouchi Shinko Chemical Industry Co., Ltd. [Vulcanization aid] Zinc oxide: manufactured by Hakusui Tech Co., Ltd. Stearic acid: manufactured by New Japan Chemical Co., Ltd. [Anti-aging agent] Nocrac 6C (trade name): manufactured by Ouchi Shinko Chemical Industry Co., Ltd. [Crosslinking agent] Sulfur: HK200-5 (trade name), manufactured by Hosoi Chemical Industry Co., Ltd.

[0111] <Production of Crosslinked Rubber> The uncrosslinked rubber composition obtained by kneading was heat-molded using a press (manufactured by Dumbbell Co., Ltd.) to produce a crosslinked rubber sheet. The heat-molding conditions were 160°C and 30 minutes, and the sheet thickness was 1 mm.

[0112] <Viscoelasticity Measurement> Samples measuring 1 mm thick x 5 mm wide x 30 mm long were punched out from the prepared sheet-like crosslinked rubber. Viscoelasticity measurements were then performed using the punched samples. The viscoelasticity measurements were performed in tensile mode at a frequency of 10 Hz, a strain of 0.1%, and a temperature range of -40°C to 65°C, with the temperature rising at a rate of 3°C / min. The equipment used was a Rheogel-E4000 manufactured by UBM. The results are shown in Table 5. The frequency used here was 10 Hz, because wet grip performance is correlated with the tan δ value at 10 Hz and 0°C when using the time-temperature conversion rule of viscoelasticity. It is known that the larger this value, the better the wet grip performance. Similarly, rolling resistance is correlated with the tan δ value at 10 Hz and 60°C, and it is known that the smaller this value, the better the rolling resistance characteristics.

[0113] (Example C2) Production of an uncrosslinked rubber composition, production of a crosslinked rubber, and measurement of viscoelasticity were carried out in the same manner as in Example C1, except that hydrogenated petroleum resin B1 was changed to hydrogenated petroleum resin B2. The results are shown in Table 6.

[0114] Comparative Example c1 An uncrosslinked rubber composition was produced, a crosslinked rubber was produced, and viscoelasticity was measured in the same manner as in Example C1, except that the hydrogenated petroleum resin B1 was replaced with the C9-based petroleum resin A1. The results are shown in Table 6.

[0115]

[0116] In Table 6, the "0°C tan δ index" indicates a relative value when the "0°C tan δ value" of Comparative Example c1 is set to 100. In Table 6, the "60°C tan δ index" indicates a relative value when the "60°C tan δ value" of Comparative Example c1 is set to 100. In Table 6, the "tan δ balance index" indicates a relative value when the value of Comparative Example c1 is set to 100 for the ratio of the "0°C tan δ value" to the "60°C tan δ value".

[0117] (Example D1) Production of an uncrosslinked rubber composition, production of a crosslinked rubber, and measurement of viscoelasticity were carried out in the same manner as in Example C1, except that hydrogenated petroleum resin B1 was changed to hydrogenated petroleum resin B3. The results are shown in Table 7.

[0118] Comparative Example d1 An uncrosslinked rubber composition was produced, a crosslinked rubber was produced, and viscoelasticity was measured in the same manner as in Example C1, except that hydrogenated petroleum resin B1 was changed to hydrogenated petroleum resin b3. The results are shown in Table 7.

[0119] Comparative Example d2 An uncrosslinked rubber composition was produced, a crosslinked rubber was produced, and viscoelasticity was measured in the same manner as in Example C1, except that the hydrogenated petroleum resin B1 was replaced with the C9-based petroleum resin A2. The results are shown in Table 7.

[0120]

[0121] (Example E1) Production of an uncrosslinked rubber composition, production of a crosslinked rubber, and measurement of viscoelasticity were carried out in the same manner as in Example C1, except that hydrogenated petroleum resin B1 was changed to hydrogenated petroleum resin B4. The results are shown in Table 8.

[0122] Comparative Example e1: An uncrosslinked rubber composition was produced, a crosslinked rubber was produced, and viscoelasticity was measured in the same manner as in Example C1, except that the hydrogenated petroleum resin B1 was replaced with the C9-based petroleum resin A3. The results are shown in Table 8.

[0123]

[0124] Example F1 An uncrosslinked rubber composition was produced, a crosslinked rubber was produced, and viscoelasticity was measured in the same manner as in Example C1, except that hydrogenated petroleum resin B1 was replaced with hydrogenated petroleum resin B5. The results are shown in Table 9.

[0125] Comparative Example f1 An uncrosslinked rubber composition was produced, a crosslinked rubber was produced, and viscoelasticity was measured in the same manner as in Example C1, except that the hydrogenated petroleum resin B1 was replaced with the C9-based petroleum resin A4. The results are shown in Table 9.

[0126]

[0127] Example G1 The production of an uncrosslinked rubber composition, the production of a crosslinked rubber, and the measurement of viscoelasticity were carried out in the same manner as in Example C1, except that the hydrogenated petroleum resin B1 was changed to the hydrogenated petroleum resin B6. The results are shown in Table 10.

[0128] (Comparative Example g1) The uncrosslinked rubber composition and the crosslinked rubber were produced and the viscoelasticity was measured in the same manner as in Example C1, except that the hydrogenated petroleum resin B1 was changed to the C9-based petroleum resin A5. The results are shown in Table 10.

[0129]

[0130] (Example H1) Production of an uncrosslinked rubber composition, production of a crosslinked rubber, and measurement of viscoelasticity were carried out in the same manner as in Example C1, except that hydrogenated petroleum resin B1 was changed to hydrogenated petroleum resin B7. The results are shown in Table 11.

[0131] (Comparative Example h1) The same procedures as in Example C1 were carried out to produce an uncrosslinked rubber composition, produce a crosslinked rubber, and measure viscoelasticity, except that the hydrogenated petroleum resin B1 was replaced with the C9-based petroleum resin A6. The results are shown in Table 11.

[0132]

[0133] (Example I1) Production of an uncrosslinked rubber composition, production of a crosslinked rubber, and measurement of viscoelasticity were carried out in the same manner as in Example C1, except that the compounding ratio during production of the uncrosslinked rubber composition was changed as shown in Table 12. The results are shown in Table 13.

[0134]

[0135] Comparative Example i1 An uncrosslinked rubber composition was produced, a crosslinked rubber was produced, and viscoelasticity was measured in the same manner as in Example H1, except that the hydrogenated petroleum resin B1 was replaced with the C9-based petroleum resin A1. The results are shown in Table 13.

[0136]

[0137] (Example J1) The uncrosslinked rubber composition, the crosslinked rubber, and the viscoelasticity measurement were carried out in the same manner as in Example C1, except that the compounding ratio in the production of the uncrosslinked rubber composition was changed to Compound C shown in Table 14 below, the kneading start temperature was changed to 130°C, and the hot molding conditions in the production of the crosslinked rubber were changed to 170°C and 40 minutes. The results are shown in Table 15.

[0138]

[0139] Comparative Example j1 An uncrosslinked rubber composition was produced, a crosslinked rubber was produced, and viscoelasticity was measured in the same manner as in Example J1, except that the hydrogenated petroleum resin B1 was replaced with the C9-based petroleum resin A1. The results are shown in Table 15.

[0140]

[0141] Note that Compound C in Table 14 is a compound suitable for sports tires, racing tires, etc., and the tan δ value at 20°C is shown in the results of the viscoelasticity measurement in Table 15. The tan δ value at 20°C correlates with dry grip performance, which is important for sports tires, racing tires, etc., and the larger this value, the better the dry grip performance.

[0142] In Table 15, the "20°C tan δ index" indicates a relative value when the "20°C tan δ value" of Comparative Example j1 is set to 100. Also in Table 15, the "60°C tan δ index" indicates a relative value when the "60°C tan δ value" of Comparative Example j1 is set to 100. Also in Table 15, the "tan δ balance index" indicates a relative value when the value of Comparative Example j1 is set to 100 for the ratio of the "20°C tan δ value" to the "60°C tan δ value".

[0143] (Example K1) The uncrosslinked rubber composition, the crosslinked rubber, and the viscoelasticity measurement were carried out in the same manner as in Example J1, except that the compounding ratio during the production of the uncrosslinked rubber composition was changed as shown in Table 16. The results are shown in Table 17.

[0144]

[0145] (Comparative Example k1) The uncrosslinked rubber composition and the crosslinked rubber were produced and the viscoelasticity was measured in the same manner as in Example K1, except that the hydrogenated petroleum resin B1 was changed to the C9-based petroleum resin A1. The results are shown in Table 17.

[0146]

[0147] It should be noted that Compound D in Table 16 is a compound suitable for sports tires, racing tires, etc., and the results of the viscoelasticity measurements in Table 17 show tan δ values ​​at 20°C.

Claims

1. A tire rubber additive comprising a hydrogenated petroleum resin which is a hydrogenated product of a C9 petroleum resin, The total number of hydrogen atoms in the hydrogenated petroleum resin (M １ The total number of hydrogen atoms bonded to the aromatic rings in the hydrogenated petroleum resin (M ２ ) ratio (M ２ / M １ ) is 0.15 to 0.

45.

2. Said ratio (M ２ / M １ 2. The tire rubber additive according to claim 1, wherein the t-value is 0.2 to 0.

4.

3. The tire rubber additive according to claim 1 or 2, wherein the softening point of the hydrogenated petroleum resin is 70 to 200°C.

4. The tire rubber additive according to any one of claims 1 to 3, wherein the softening point of the hydrogenated petroleum resin is 105 to 200°C.

5. The tire rubber additive according to any one of claims 1 to 4, wherein the hydrogenated petroleum resin has an iodine value of 20 or less.

6. An uncrosslinked rubber composition comprising a tire rubber component, a tire rubber additive according to any one of claims 1 to 5, and a crosslinking agent.

7. A crosslinked rubber obtained by crosslinking the uncrosslinked rubber composition according to claim 6.

8. A tire containing the crosslinked rubber described in claim 6.

9. A tire comprising the crosslinked rubber according to claim 7 in a tread portion.