Hydrogenated petroleum resin and rubber composition for tire tread comprising same

Abstract

The present invention relates to a hydrogenated petroleum resin capable of simultaneously improving braking performance and fuel efficiency of a rubber composition for tire treads, and a rubber composition for tire treads comprising the same.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims the benefit of priority of Korean Patent Application No. 10-2022-0102534, filed on August 17, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0003] The present invention relates to a hydrogenated petroleum resin and a rubber composition for tire tread containing the same. Background Art

[0004] Energy consumption efficiency is determined by measuring the rolling resistance (RR) and wet grip of the tire. Rolling resistance refers to the energy loss between the tire and the road surface when driving. The lower the rolling resistance, the higher the fuel efficiency. Wet grip is related to braking performance on wet roads such as rainy roads, which is related to safety.

[0005] In tire development, improving fuel efficiency by reducing rolling resistance is one of the main tasks. However, there is a trade-off relationship between rolling resistance and braking force, so when rolling resistance is reduced, there is a problem of deterioration in braking performance.

[0006] The rubber composition for tire treads is composed of raw rubber, fillers and other additives, and the physical properties can be controlled by changing the raw material type or changing the composition. Therefore, efforts are continuing to develop rubber compositions for tire treads that have an appropriate balance between the desired physical properties. Summary of the invention

[0007] Technical issues

[0008] The present invention provides a hydrogenated petroleum resin capable of simultaneously improving the braking performance and rolling resistance performance of a rubber composition for tire treads and a composition for tire treads containing the hydrogenated petroleum resin.

[0009] Technical Solution

[0010] In order to achieve the above object, according to one embodiment of the present invention,

[0011] Provided is a hydrogenated petroleum resin obtained by polymerization and hydrogenation of a monomer mixture comprising dicyclopentadiene, an aromatic vinyl monomer and optionally an olefin monomer, wherein the aromaticity of the hydrogenated petroleum resin is 15% or less.

[0012] According to another embodiment of the present invention, there is provided a rubber composition for a tire tread, the rubber composition including a hydrogenated petroleum resin.

[0013] Effects of the Invention

[0014] The hydrogenated petroleum resin of the present invention has excellent compatibility with rubber, so when it is applied to a rubber composition for tire treads, the braking performance can be maximized without significantly increasing rolling resistance. Therefore, the rubber composition for tire treads containing the hydrogenated petroleum resin has excellent braking force and fuel efficiency, and is suitable for manufacturing high-quality tires. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The wet grip test (Tan 0°C) results of the rubber compositions for tire treads of Examples and Comparative Examples are shown;

[0016] Figure 2 The results of the rolling resistance test (Tan 70° C., expressed in reciprocal) of the rubber compositions for tire treads of Examples and Comparative Examples are shown. DETAILED DESCRIPTION

[0017] The term "petroleum resin" used herein refers to a resin polymerized by including dicyclopentadiene monomers, specifically a resin polymerized by a monomer mixture comprising dicyclopentadiene, an aromatic vinyl monomer, and an optional olefin monomer. In addition, "hydrogenated petroleum resin" refers to a resin obtained by hydrogenating the above petroleum resin, i.e., hydrogenating the resin.

[0018] Furthermore, the term "hydrogenation" or "hydrogen addition reaction" used herein refers to a reaction of converting an unsaturated bond such as a double bond or the like into a single bond by adding hydrogen to the unsaturated bond.

[0019] In addition, the term "monomer mixture" refers to a monomer group without solvent or additives. "Monomer composition" refers to a monomer mixture dispersed in a solvent and may also include an initiator and other additives.

[0020] In the present invention, the terms "first", "second", etc. are used to describe various components, and these terms are used only to distinguish one component from other components.

[0021] In addition, the terms used in this specification are only used to describe exemplary embodiments and are not intended to limit the present invention. Unless otherwise expressly stated, the singular includes the plural. It should also be understood that the terms "including", "equipped with" or "having" when used in this specification specify the presence of the features, steps, components and / or their combinations, but do not exclude the presence or addition of one or more other features, steps, components and / or their combinations.

[0022] The present invention can be modified in various ways and has various forms, and specific embodiments will be described and described in detail below. However, it should be understood that this description is not intended to limit the invention to the specific forms disclosed, but rather, is intended to cover all modifications, equivalents and alternatives that fall within the spirit and scope of the present invention.

[0023] Hereinafter, the hydrogenated petroleum resin of the present invention and the rubber composition for tire tread comprising the same will be described in more detail.

[0024] Hydrogenated petroleum resin

[0025] The hydrogenated petroleum resin of the present invention can be obtained by polymerization and hydrogenation of a monomer mixture containing dicyclopentadiene, an aromatic vinyl monomer and optionally an olefin monomer, and has an aromaticity of 15% or less.

[0026] Since the hydrogenated petroleum resin has excellent compatibility with the raw rubber contained in the rubber composition for tire tread, it is suitable to be contained as an additive for providing adhesion. Therefore, the hydrogenated petroleum resin improves the braking performance of the composition for tire tread while minimizing the reduction of fuel efficiency.

[0027] The aromatic vinyl monomer may have 6 to 20 carbon atoms. Specifically, one or more selected from styrene, α-methylstyrene, p-methylstyrene, indene, methylindene, and vinyltoluene may be used as the aromatic vinyl monomer.

[0028] The olefin monomer may have a carbon number of 2 to 20, and specifically may be one or more selected from piperylene, isoprene, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, and 1-hexadecene.

[0029] In one embodiment, styrene may be used as the aromatic vinyl monomer, and piperylene may be used as the olefin monomer.

[0030] Dicyclopentadiene is used as a main monomer, and specifically, its content may be 50 parts by weight or more, 60 parts by weight or more, or 70 parts by weight or more, and 90 parts by weight or less, or 80 parts by weight or less, relative to 100 parts by weight of the monomer mixture.

[0031] The content of the aromatic vinyl monomer may be 10 parts by weight or more, or 20 parts by weight or more, and 30 parts by weight or less relative to 100 parts by weight of the monomer mixture. When the content of the aromatic vinyl monomer satisfies the above range, it can exhibit excellent compatibility and excellent adhesion with the raw rubber contained in the rubber composition for tire treads.

[0032] Olefin monomer is an optional comonomer, and its content can be 0 to 20 parts by weight, or more than 0 parts by weight, or more than 0.7 parts by weight, or more than 1 part by weight, and less than 15 parts by weight, or less than 10 parts by weight, relative to 100 parts by weight of the monomer mixture. From the perspective of compatibility with the raw rubber, the content of the olefin monomer is preferably less than 20 parts by weight relative to 100 parts by weight of the monomer mixture.

[0033] The remainder of 100 parts by weight of the monomer mixture except the aromatic vinyl monomer and the olefin monomer may be dicyclopentadiene. In other words, the monomer mixture may not further contain any comonomer except dicyclopentadiene, the aromatic vinyl monomer and the optionally contained olefin monomer.

[0034] Specifically, 100 parts by weight of the monomer mixture may consist of 10 to 30 parts by weight of the aromatic vinyl monomer, 0 to 20 parts by weight of the olefin monomer, and the remainder of dicyclopentadiene.

[0035] Alternatively, 100 parts by weight of the monomer mixture may consist of 20 to 30 parts by weight of the aromatic vinyl monomer, 0 to 15 parts by weight of the olefin monomer, and the remainder dicyclopentadiene.

[0036] Alternatively, 100 parts by weight of the monomer mixture may consist of 20 to 30 parts by weight of the aromatic vinyl monomer, 0.7 to 15 parts by weight of the olefin monomer, and the remainder dicyclopentadiene.

[0037] Alternatively, 100 parts by weight of the monomer mixture may consist of 20 to 30 parts by weight of the aromatic vinyl monomer, 0.7 to 10 parts by weight of the olefin monomer, and the remainder dicyclopentadiene.

[0038] The hydrogenated petroleum resin according to one embodiment of the present invention satisfies the above-mentioned monomer composition and satisfies the aromaticity of 15% or less, thereby showing excellent compatibility with the raw rubber contained in the tire tread composition. The aromaticity is the content of aromatic double bonds in the petroleum resin, which can be measured by NMR analysis, and the specific measurement method will be described in the following experimental examples.

[0039] In order to ensure the above-mentioned effect, in improving the braking performance and rolling resistance performance of the tire tread composition, the aromaticity of the hydrogenated petroleum resin is more preferably below 15% or below 14.5% and is above 3%, above 5%, above 6%, or above 6.5%. When the aromaticity of the hydrogenated petroleum resin exceeds 15%, the compatibility variation with the raw rubber causes the braking performance or rolling resistance performance variation, therefore, preferably satisfies the above-mentioned range.

[0040] Meanwhile, the weight average molecular weight of hydrogenated petroleum resin is preferably more than 500g / mol, or more than 600g / mol, or more than 650g / mol, and less than 1,000g / mol, or less than 950g / mol, or less than 900g / mol. When the weight average molecular weight of hydrogenated petroleum resin meets the above range, hydrogenated petroleum resin shows excellent rolling resistance performance, and shows improved braking performance, so it is preferred.

[0041] Furthermore, the molecular weight distribution (PDI) of the hydrogenated petroleum resin may be in the range of 1.0 to 2.0, preferably 1.2 or more or 1.5 or more, and 1.8 or less or 1.75 or less, and due to the narrow molecular weight distribution, the hydrogenated petroleum resin exhibits uniform physical properties.

[0042] The weight average molecular weight and molecular weight distribution of the hydrogenated petroleum resin can be measured by gel permeation chromatography, and the detailed measurement method will be described in the following experimental examples.

[0043] The softening point of the hydrogenated petroleum resin may be above 90° C., or above 95° C., and below 120° C., below 115° C., or below 110° C. If the softening point of the hydrogenated petroleum resin is too high or too low, the compatibility with the raw rubber may be deteriorated, and there may be a problem that only one of the rolling resistance performance or the braking performance is outstanding, so it is best to meet the above range.

[0044] The hydrogenated petroleum resin exhibits excellent physical properties, with a heating weight loss of 3.0% or less, preferably a heating weight loss of 2.8% or less, or 2.7% or less. The lower the heating weight loss, the better the hydrogenated petroleum resin, and theoretically the heating weight loss can be 0%.

[0045] The hydrogenated petroleum resin can be obtained by polymerization and hydrogenation of the above-mentioned monomer mixture. Specifically, the hydrogenated petroleum resin can be prepared by a preparation method comprising the following steps: preparing the petroleum resin by thermally polymerizing a monomer mixture containing dicyclopentadiene, an aromatic vinyl monomer and an optional olefin monomer; and hydrogenating the petroleum resin. The aromaticity of the hydrogenated petroleum resin can be controlled according to the content ratio of the reactants, reaction conditions, hydrogenation conditions, etc. when preparing the petroleum resin.

[0046] The monomer mixture may be introduced into the thermal polymerization reaction in a state of being dispersed in a solvent, that is, in the form of a monomer composition.

[0047] The solvent that can be used to prepare the monomer composition is not particularly limited, and for example, one or more selected from pentane, hexane, heptane, nonane, decane, benzene, toluene, and xylene can be used.

[0048] In addition, the monomer composition may further include additives commonly used in the technical field to which the present invention belongs, such as antioxidants and polymerization inhibitors.

[0049] The method of thermally polymerizing the monomer mixture is not particularly limited. However, for example, the method may include a) a first stage polymerization of thermally polymerizing the monomer mixture in a continuous stirred tank reactor (CSTR) and b) a second stage polymerization of thermally polymerizing the reaction product of the first stage polymerization in a plug flow reactor (PFR). In this regard, as described above, the monomer mixture may be used in the form of the monomer mixture dissolved in a solvent.

[0050] When thermal polymerization is carried out in the above two stages, the heat of polymerization reaction can be easily controlled, the conversion rate of monomers or the polymerization rate is significantly improved, and the molecular weight distribution is narrow, thereby providing a petroleum resin having uniform physical properties.

[0051] The reaction temperature (T1) in stage a) may be 210 to 270° C., or 220 to 270° C. When the reaction is carried out at the above reaction temperature, the conversion rate or polymerization rate of the monomer is excellent, and the occurrence of side reactions such as crosslinking reactions can be suppressed.

[0052] The reaction pressure in stage a) may be 1 bar to 40 bar, or 5 bar to 35 bar, or 10 bar to 30 bar. When carried out under the above reaction pressure, the reactivity of the monomers can be increased as long as there is no risk of safety accidents.

[0053] The reaction time in stage a) may be 10 to 90 minutes, or 20 to 80 minutes, or 30 to 70 minutes. When the reaction time is too short, the suppression of side reactions by mixing the raw materials may be insufficient, and when the reaction time is too long, the productivity of the final resin may decrease and the molecular weight distribution may become broad. From this point of view, it is preferred to control the reaction time within the above range.

[0054] The reaction temperature (T2) in stage b) can be within the range of ±30°C of the reaction temperature (T1) in stage a), i.e., T1-30°C to T1+30°C, or T1-20°C to T1+20°C, or T1-15°C to T1+15°C. When carried out at the above reaction temperature, side reactions can be suppressed and productivity can be improved.

[0055] Furthermore, when the temperature difference between the stage a) and the stage b) is controlled within ±30° C. as described above, generation of unreacted oligomers can be minimized, and a dicyclopentadiene-based resin having a narrow molecular weight distribution can be prepared.

[0056] The reaction pressure in stage b) may be 1 bar to 40 bar, or 5 bar to 35 bar, or 10 bar to 30 bar. When the reaction pressure is too low, the reactivity may be low due to evaporation of the monomer, and when the pressure is too high, the risk of safety accidents during the process is high. From this point of view, it is preferred to control the reaction pressure within the above range.

[0057] The reaction time in stage b) can be 1 to 4 times, or 1 to 3 times, or 1 to 2 times the reaction time in stage a). When the reaction time is too short compared to the reaction time of the polymerization in stage a), the reaction may not proceed sufficiently, and when the reaction time is too long, side reactions may occur. From this perspective, it is preferred to control the reaction time within the above range.

[0058] In addition, the internal volume of the PFR used in the polymerization of stage b) can be 1 to 3 times, or 1 to 2.5 times, or 1 to 2 times the internal volume of the CSTR used in the polymerization of stage a). When the internal volume of the PFR is too small compared to the internal volume of the CSTR, the polymerization in the PFR may not be sufficient, and a large amount of impurities such as wax may remain. When the internal volume of the PFR is too large compared to the internal volume of the CSTR reactor, the effect of applying the CSTR reactor is poor, and the control of the initial heat of the reaction is insufficient, so it is difficult to control the reaction temperature. From this perspective, it is preferred to control the internal volume of the PFR within the above range.

[0059] The hydrogenation reaction or hydrogenation reaction is not particularly limited and can be carried out according to methods known in the art to which the present invention belongs. The hydrogenation reaction is a reaction in which an unsaturated bond, such as a double bond, is converted into a single bond by hydrogenation. The hydrogenated petroleum resin can be obtained by hydrogenating a petroleum resin.

[0060] The hydrogenation reaction can be carried out according to methods known in the art to which the present invention belongs. For example, the obtained petroleum resin can be introduced into a continuous hydrogenation tank equipped with a hydrogenation catalyst for hydrogenation reaction.

[0061] The hydrogenation catalyst is not particularly limited, but any known hydrogenation catalyst may be used. For specific examples, one or more selected from Ni, Fe, Cu, Co, Mo, Pd, Rh, Pt, Nb, Au, Rd, and Raney Ni may be used as the hydrogenation catalyst.

[0062] To improve reactivity, the amount of the hydrogenation catalyst used may be 0.1 parts by weight or more, 0.3 parts by weight or more, or 0.5 parts by weight or more, and 1.5 parts by weight or less, or 1.0 parts by weight or less, relative to 100 parts by weight of the petroleum resin, but is not limited thereto.

[0063] The hydrogenation conditions are not particularly limited and can be appropriately controlled according to the type and amount of the catalyst used, the amount of hydrogen added, etc. For example, the hydrogenation reaction can be carried out at a pressure of 50 bar to 150 bar and a temperature range of 150° C. to 300° C. When the hydrogenation reaction is carried out at the above pressure and temperature, the destruction of the molecular structure can be prevented.

[0064] Furthermore, hydrogen may be introduced continuously so as to maintain a constant reaction pressure during the hydrogenation reaction.

[0065] Meanwhile, the hydrogenation reaction can be carried out once under the above conditions, but can also be carried out in two or more times to achieve the desired aromaticity. When the hydrogenation reaction is carried out two or more times, the conditions of each reaction can be the same or different.

[0066] The hydrogenated petroleum resin prepared by the above method has excellent compatibility with the raw rubber used in the tire tread composition, and due to its high adhesive property, the hydrogenated petroleum resin can improve the braking performance of the tire tread composition while minimizing the increase in rolling resistance. Therefore, the hydrogenated petroleum resin can be usefully used as a tackifying resin for the tire tread composition.

[0067] Rubber composition for tire tread

[0068] The rubber composition for tire tread of the present invention includes the raw rubber and the above-mentioned hydrogenated petroleum resin, thereby exhibiting high braking performance and fuel efficiency.

[0069] The hydrogenated petroleum resin is included in the rubber composition for tire tread to further improve the adhesion between rubbers and to improve the miscibility, dispersibility and processability of fillers and other additives, thereby improving the physical properties of the rubber composition.

[0070] Specifically, since the hydrogenated petroleum resin satisfies the above-mentioned monomer composition and aromaticity, it exhibits excellent compatibility with raw rubber and additives, and can minimize an increase in rolling resistance while providing improved braking performance due to excellent adhesion.

[0071] The raw material rubber is not particularly limited as long as it has an olefin double bond (carbon-carbon double bond), and natural rubber, synthetic rubber, or a mixture thereof may be used in the mixture.

[0072] For example, the raw rubber may include one or more selected from natural rubber, butadiene rubber, nitrile rubber, silicone rubber, isoprene rubber, styrene-butadiene rubber (SBR), isoprene-butadiene rubber, styrene-isoprene-butadiene rubber, acrylonitrile-butadiene rubber (NBR), ethylene-propylene-diene rubber, halogenated butyl rubber, halogenated isoprene rubber, halogenated isobutylene copolymer, chloroprene rubber, butyl rubber and halogenated isobutylene-para-methylstyrene rubber.

[0073] In one embodiment, the rubber composition for tire tread may include hydrogenated petroleum resin in an amount of 10 parts by weight or more, or 20 parts by weight or more, and 50 parts by weight or less, or 40 parts by weight or less, or 30 parts by weight or less, relative to 100 parts by weight of raw rubber. When the content of hydrogenated petroleum resin is less than 10 parts by weight relative to 100 parts by weight of raw rubber, it is difficult to ensure dispersibility, processability and braking performance, and when it exceeds 50 parts by weight, braking performance becomes excellent, but there may be a problem that rolling resistance becomes too high.

[0074] The rubber composition for tire tread may further include one or more selected from the group consisting of fillers, silane coupling agents, anti-aging agents, softeners, vulcanizing agents, vulcanization accelerators, and vulcanization accelerating aids.

[0075] Fillers are added to improve the durability and heat resistance of the tire and to improve the chipping resistance, cut resistance and wear resistance. For example, carbon black and / or silica may be used.

[0076] The nitrogen surface area per gram (N2SA) of carbon black can be 30 m 2 / g to 300m 2 / g, and the oil absorption of di-n-butyl phthalate (DBP) can be 60cc / 100g to 180cc / 100g.

[0077] When the nitrogen surface area per gram of carbon black exceeds 300m 2 / g, the processing properties of the tire rubber composition may be unfavorable, and when it is less than 30 m 2 / g, the reinforcing performance of carbon black as a filler may be unfavorable. In addition, when the DBP oil absorption of carbon black exceeds 180cc / 100g, the processability of the rubber composition may deteriorate, and when it is less than 60cc / 100g, the reinforcing performance of carbon black as a filler may be unfavorable.

[0078] The content of carbon black may be 1 to 50 parts by weight, or 5 to 30 parts by weight, relative to 100 parts by weight of the raw rubber. When the content of carbon black is less than 1 part by weight, the reinforcing performance of carbon black as a filler may deteriorate, and when the content of carbon black exceeds 50 parts by weight, the processing performance of the rubber composition may be unfavorable.

[0079] The nitrogen surface area per gram of silicon dioxide (N2SA) can be 100m 2 / g to 180m 2 / g, the surface area of ​​each gram of hexadecyltrimethylammonium bromide (CTAB) can be 110m 2 / g to 170m 2 / g. The present invention is not limited thereto.

[0080] When the nitrogen surface area per gram of silicon dioxide is less than 100m 2 / g, the reinforcing performance of silica as a filler may be unfavorable, and when it exceeds 180m 2 / g, the processing properties of the rubber composition may be unfavorable. In addition, when the CTAB surface area per gram of silica is less than 110m 2 / g, the reinforcing performance of silica as a filler may be unfavorable, and when it exceeds 170m 2 / g, the processability of the rubber composition may be disadvantageous.

[0081] The content of silica may be 10 to 150 parts by weight, preferably 50 to 100 parts by weight, relative to 100 parts by weight of the raw rubber. When the content of silica is less than 10 parts by weight, the strength improvement of the rubber may be disadvantageous or the fuel efficiency of the tire may decrease, and when the content of silica exceeds 150 parts by weight, the wear performance may decrease.

[0082] Meanwhile, when silica is used, a silane coupling agent may be further included to mix the silica. The silane coupling agent may include vinyl trichlorosilane, vinyl triethoxysilane, vinyl tri(β-methoxyethoxy)silane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, 3-chloropropyl trimethoxysilane, 3-chloropropyl triethoxysilane, 3-mercaptopropyl trimethoxysilane, 3-mercaptopropyl triethoxysilane, bis(3-(triethoxysilyl)propyl) disulfide, bis(3-triethoxysilylpropyl) trisulfide, bis(3-(triethoxysilyl)propyl) tetrasulfide, bis(2-triethoxysilylethyl) tetrasulfide, bis(3-trimethoxysilylpropyl) tetrasulfide, bis(2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyl trimethoxysilane, 3-mercaptopropyl triethoxysilane, 2-mercaptoethyl trimethoxysilane, 2-mercaptopropyl trimethoxysilane, 2-mercaptopropyl trimethoxysilane, 2-mercaptopropyl triethoxysilane, 2-mercaptopropyl trimethoxysilane, 2-mercaptopropyl trimethoxysilane, 2-mercaptopropyl triethoxysilane, 2-mercaptopropyl trimethoxysilane, 2-mercaptopropyl trimethoxysilane, 2-mercaptopropyl triethoxysilane, 2-mercaptopropyl trimethoxysilane, 2-mercaptopropyl trimethoxysilane, 2-mercaptopropyl triethoxysilane, 2-mercaptopropyl trimethoxysilane, 2-mercaptopropyl trimethoxysilane, 2-mercaptopropyl triethoxysilane, 2-mercaptopropyl trimethoxysilane. Silane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzoyl tetrasulfide, 3-triethoxysilylpropylmethacrylate monosulfide, 3-trimethoxysilylpropylmethacrylate monosulfide, bis(3-diethoxymethylsilyl)tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, dimethoxymethylsilylpropylbenzothiazolyl tetrasulfide, etc. These compounds may be used alone or in combination of two or more thereof. Preferably, bis(3-(triethoxysilyl)propyl)tetrasulfide may be used.

[0083] In order to improve the dispersibility of silica, the content of the silane coupling agent may be 1 to 15 parts by weight, or 5 to 10 parts by weight, relative to 100 parts by weight of the raw rubber. When the content of the silane coupling agent is less than 1 part by weight, the dispersibility of silica may be poorly improved, resulting in a decrease in the processability or fuel efficiency of the rubber. When it exceeds 20 parts by weight, the interaction between silica and rubber is too strong, so the fuel efficiency may be excellent, but the braking performance may be greatly reduced.

[0084] The anti-aging agent is an additive for preventing the chain reaction of the tire being automatically oxidized by oxygen. The anti-aging agent may include any one appropriately selected from amine-based anti-aging agents, phenol-based anti-aging agents, quinolone-based anti-aging agents, imidazole-based anti-aging agents, carbamate metal salts, waxes and combinations thereof.

[0085] The amine-based antioxidant can be any one selected from N-phenyl-N'-(1,3-dimethyl)-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, N,N'-diaryl-p-phenylenediamine, N-phenyl-N'-cyclohexyl-p-phenylenediamine, N-phenyl-N'-octyl-p-phenylenediamine and combinations thereof. The phenol-based anti-aging agent can be any one selected from 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-isobutylenebis(4,6-dimethylphenol), 2,6-di-tert-butyl-p-cresol and combinations thereof; the quinolone-based anti-aging agent can include 2,2,4-trimethyl-1,2-dihydroquinoline and its derivatives, specifically any one selected from 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, 6-anilino-2,2,4-trimethyl-1,2-dihydroquinoline, 6-dodecyl-2,2,4-trimethyl-1,2-dihydroquinoline and combinations thereof; the wax is preferably a waxy hydrocarbon.

[0086] Considering that the anti-aging agent should have high solubility in rubber, low volatility, no activity to rubber, and no effect on vulcanization in addition to its anti-aging effect, the amount of the anti-aging agent included can be 1 to 10 parts by weight relative to 100 parts by weight of the raw rubber.

[0087] Adding softening agent is in order to facilitate processing by giving rubber plasticity, or reduce the hardness of vulcanized rubber. Can use oil based on petroleum, vegetable oil and combination thereof. Specifically, softening agent can comprise processed fraction aromatic extract (TDAE) oil, gentle extraction solvent (MES) oil, residual aromatic extract (RAE) oil or heavy naphthenic oil. Preferably, TDAE oil can be used.

[0088] From the viewpoint of processability, the amount of the softener used is preferably 0 to 20 parts by weight relative to 100 parts by weight of the raw rubber.

[0089] The vulcanizing agent may preferably include a sulfur-based vulcanizing agent, and the sulfur-based vulcanizing agent may include an inorganic vulcanizing agent, such as sulfur (S) powder, insoluble sulfur (S), precipitated sulfur (S), colloidal sulfur, etc., and the organic vulcanizing agent may specifically include a vulcanizing agent for preparing elemental sulfur or sulfur, such as disulfide amine, polymerized sulfur, etc.

[0090] When the content of the vulcanizing agent is 0.5 parts by weight or more or 1.0 parts by weight or more and 4.0 parts by weight or less or 3.0 parts by weight or less relative to 100 parts by weight of the raw rubber, this is preferred from the perspective of ensuring appropriate vulcanization effect and stability of the raw rubber.

[0091] Vulcanization accelerators are accelerators that accelerate the vulcanization rate or accelerate the delayed action in the initial vulcanization step.

[0092] The vulcanization accelerator may include, for example, thiuram accelerators such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, and tetraethylthiuram disulfide; thiazole accelerators such as 2-mercaptobenzothiazole and dibenzothiazole disulfide; sulfenamide accelerators such as n-cyclohexyl-2-benzothiazolesulfenamide and N-oxydiethylene-2-benzothiazolesulfenamide; aldehyde-amine accelerators such as n-butyraldehyde-aniline condensate and butyraldehyde-monobutylamine condensate; aldehyde-ammonia accelerators such as hexamethylenetetramine; thiourea accelerators such as diphenylthiourea; and guanidine accelerators such as 1,3-diphenylguanidine. When these vulcanization accelerators are mixed, one of them may be used alone, or a combination of two or more of them may be used. For example, 1,3-diphenylguanidine (DPG) and N-cyclohexyl-2-benzothiazolesulfenamide (CBTS) may be used as vulcanization accelerators.

[0093] From the viewpoint of improving physical properties, the amount of the vulcanization accelerator used is preferably 0.1 to 10 parts by weight relative to 100 parts by weight of the raw rubber.

[0094] Vulcanization accelerators are used in combination with vulcanization accelerators to further enhance the accelerating effect.

[0095] The vulcanization accelerator may include metal oxides such as zinc oxide and magnesium oxide; metal hydroxides such as calcium hydroxide; metal carbonates such as zinc carbonate and basic zinc carbonate; fatty acids such as stearic acid and oleic acid; aliphatic metal salts such as zinc stearate and magnesium stearate; amines such as n-butylamine and dicyclohexylamine; ethylene glycol dimethacrylate, diallyl phthalate, N,N-m-phenylenedimaleimide, triallyl isocyanurate, trimethylolpropane trimethacrylate, etc. When these vulcanization accelerators are mixed, one of them may be used alone, or two or more of them may be used in combination.

[0096] From the viewpoint of improving physical properties, the amount of the vulcanization accelerator used is preferably 0.1 to 10 parts by weight relative to 100 parts by weight of the raw rubber.

[0097] Meanwhile, the rubber composition for tire tread may further include various additives used in the rubber industry, for example, vulcanization retarders, peptizers, processing oils, plasticizers and other additional additives.

[0098] The rubber composition for tire treads can be prepared by mixing the above-mentioned components using a mixer (for example, a mixing extruder, a Banbury mixer, a roll or an internal mixer, etc.).

[0099] The rubber composition for tire tread prepared by the above method can be used as a material constituting the tread portion (and a cover portion including the tread portion) that contacts the road surface, and can be further used to constitute various rubber components of the tire, for example, sidewalls, sidewall inserts, apex rubbers, bead covers, wire coatings, inner liners, etc.

[0100] A tire manufactured using the rubber composition for tire tread has high grip, exhibits excellent driving stability and braking performance, and has low rolling resistance, and is thus suitable for use as a fuel-saving, high-performance tire.

[0101] Hereinafter, the functions and effects of the present invention will be described in more detail with reference to specific exemplary embodiments of the present invention. However, these exemplary embodiments are only used to illustrate the present invention and do not limit the scope of the present invention.

[0102] [Example]

[0103] <Preparation of hydrogenated petroleum resin>

[0104] Example 1-1

[0105] 693 g of dicyclopentadiene, 300 g of styrene and 7 g of piperylene were mixed in 1000 g of xylene solvent to prepare a monomer composition, which was continuously introduced into a continuous stirred tank reactor (CSTR) with an internal volume of 0.416 L and stirred for reaction at a temperature of 265° C. and a pressure of 25 bar for 42 minutes to prepare a primary polymer.

[0106] The primary polymer prepared above was continuously introduced into a plug flow reactor (PFR) with an internal volume of 0.590 L connected to a continuous stirred tank reactor, and polymerized at a temperature of 277° C. and a pressure of 25 bar for 63 minutes. The polymerized product was decompressed at 200° C. for 30 minutes to recover the petroleum resin.

[0107] Hydrogenated petroleum resin was prepared by hydrogenating the petroleum resin three times at a temperature of 260° C. and a pressure of 100 bar using 0.5 wt % of a palladium catalyst and a hydrogen flow rate of 4 NL / min relative to the total weight of the petroleum resin.

[0108] Example 1-2

[0109] A hydrogenated petroleum resin was prepared in the same manner as in Example 1-1 except that the petroleum resin was hydrogenated once.

[0110] Examples 1-3

[0111] 800 g of dicyclopentadiene and 200 g of styrene were mixed in 1000 g of xylene solvent to prepare a monomer composition. The monomer composition was polymerized in the same manner as in Example 1-1 to prepare a petroleum resin.

[0112] Hydrogenated petroleum resin was prepared by hydrogenating twice at a temperature of 260° C. and a pressure of 100 bar using 0.5 wt % of a palladium catalyst and a hydrogen flow rate of 4 NL / min relative to the total weight of the petroleum resin.

[0113] Examples 1-4

[0114] 760 g of dicyclopentadiene, 200 g of styrene and 40 g of piperylene were mixed in 1000 g of xylene solvent to prepare a monomer composition. Using this monomer composition, a hydrogenated petroleum resin was prepared in the same manner as in Example 1-3.

[0115] Examples 1-5

[0116] 730 g of dicyclopentadiene, 200 g of styrene and 70 g of piperylene were mixed in 1000 g of xylene solvent to prepare a monomer composition. Using this monomer composition, a hydrogenated petroleum resin was prepared in the same manner as in Example 1-3.

[0117] Examples 1-6

[0118] 680 g of dicyclopentadiene, 200 g of styrene and 120 g of piperylene were mixed in 1000 g of xylene solvent to prepare a monomer composition. Using this monomer composition, a hydrogenated petroleum resin was prepared in the same manner as in Example 1-3.

[0119] Examples 1-7

[0120] 750 g of dicyclopentadiene and 250 g of styrene were mixed in 1000 g of xylene solvent to prepare a monomer composition. Using this monomer composition, a hydrogenated petroleum resin was prepared in the same manner as in Example 1-1.

[0121] Examples 1-8

[0122] 675 g of dicyclopentadiene, 250 g of styrene and 75 g of piperylene were mixed in 1000 g of xylene solvent to prepare a monomer composition. Using this monomer composition, a hydrogenated petroleum resin was prepared in the same manner as in Example 1-2.

[0123] Examples 1-9

[0124] A monomer composition was prepared by mixing 693 g of dicyclopentadiene, 300 g of styrene and 7 g of piperylene in 1000 g of xylene solvent. A hydrogenated petroleum resin was prepared using the monomer composition in the same manner as in Example 1-3.

[0125] Examples 1-10

[0126] 693 g of dicyclopentadiene, 300 g of styrene and 7 g of piperylene were mixed in 1000 g of xylene solvent to prepare a monomer composition, which was continuously introduced into a continuous stirred tank reactor (CSTR) with an internal volume of 0.416 L, and stirred for reaction for 42 minutes at a temperature of 265° C. and a pressure of 25 bar to prepare a primary polymer.

[0127] The primary polymer prepared above was continuously introduced into a plug flow reactor (PFR) with an internal volume of 0.590 L connected to a continuous stirred tank reactor, and polymerized at a temperature of 277° C. and a pressure of 25 bar for 63 minutes. The polymer product was decompressed at 200° C. for 30 minutes to recover the petroleum resin.

[0128] Hydrogenated petroleum resin was prepared by performing hydrogenation twice at a temperature of 260° C. and a pressure of 100 bar, using 0.5 wt % of a palladium catalyst and a hydrogen flow rate of 4 NL / min relative to the total weight of the petroleum resin.

[0129] Comparative Example 1-1

[0130] 805.1 g of dicyclopentadiene, 170 g of styrene and 24.9 g of piperylene were mixed in 1000 g of xylene solvent to prepare a monomer composition, which was continuously introduced into a continuous stirred tank reactor (CSTR) with an internal volume of 0.416 L, and stirred for reaction at a temperature of 265° C. and a pressure of 25 bar for 42 minutes to prepare a primary polymer.

[0131] The primary polymer prepared above was continuously introduced into a plug flow reactor (PFR) with an internal volume of 0.590 L connected to a continuous stirred tank reactor, and polymerized at a temperature of 277° C. and a pressure of 25 bar for 63 minutes. The polymerized product was decompressed at 200° C. for 30 minutes to recover the petroleum resin.

[0132] Comparative Example 1-2

[0133] 693 g of dicyclopentadiene, 300 g of styrene and 7 g of piperylene were mixed in 1000 g of a xylene solvent to prepare a monomer composition. Using this monomer composition, a petroleum resin was prepared in the same manner as in Comparative Example 1-1.

[0134] Comparative Examples 1-3

[0135] 693 g of dicyclopentadiene, 300 g of styrene and 7 g of piperylene were mixed in 1000 g of xylene solvent to prepare a monomer composition, which was continuously introduced into a continuous stirred tank reactor (CSTR) with an internal volume of 0.416 L, and stirred for reaction for 42 minutes at a temperature of 265° C. and a pressure of 25 bar to prepare a primary polymer.

[0136] The primary polymer prepared above was continuously introduced into a plug flow reactor (PFR) with an internal volume of 0.590 L connected to a continuous stirred tank reactor, and polymerized at a temperature of 272° C. and a pressure of 25 bar for 63 minutes. The polymerized product was decompressed at 200° C. for 30 minutes to recover the petroleum resin.

[0137] Under the conditions of temperature of 250° C. and pressure of 100 bar, a hydrogenation was carried out once using 0.5 wt % of palladium catalyst and a hydrogen flow rate of 4 NL / min relative to the total weight of the petroleum resin to prepare hydrogenated petroleum resin.

[0138] Experimental Example 1: Evaluation of Physical Properties of Petroleum Resin

[0139] (1) Softening point (℃)

[0140] The softening point was measured using the ring and ball softening method (ASTM E 28).

[0141] Specifically, the petroleum resin is dissolved and placed in a ring frame, which is placed in a beaker filled with glycerin. A ball is then placed on the ring filled with the petroleum resin and heated at a heating rate of 2.5°C / min. The temperature (softening point) when the resin melts and the ball falls is measured.

[0142] (2) Weight average molecular weight (Mw, g / mol) and molecular weight distribution (PDI)

[0143] The polystyrene-equivalent weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (PDI) were measured by gel permeation chromatography (GPC) (Infinity 1260). The molecular weight distribution was calculated by dividing the measured weight average molecular weight by the number average molecular weight.

[0144] The petroleum polymer to be measured was dissolved in tetrahydrofuran at a concentration of 0.05% by weight, and 10 μl of it was injected into the GPC. The GPC was analyzed at 35°C with tetrahydrofuran as the mobile phase and introduced at a flow rate of 1 mL / min. The chromatographic column was a guard column connected in series with three columns of PL gel 5μm 50A, PL gel 5μm100A, and oligopore 300A. The detector was a refractive index detector (RID), and the molecular weight was measured at 30°C.

[0145] Twelve polystyrene standards with molecular weights (g / mol) of 104 / 118 / 236 / 580 / 1480 / 2340 / 2970 / 5030 / 8450 / 10850 / 20650 / 24600 were used.

[0146] (3) Heating weight loss (%)

[0147] 3 g of petroleum resin was placed in a heating weight loss analyzer (AND MX-50) and heated at 180°C for 1 hour. The weight change before and after heating was converted into percentage to calculate the heating weight loss.

[0148] (4) Melt viscosity (MV 180 and MV 200, cPs)

[0149] The melt viscosity value was measured according to ASTM D3236. 8 g of petroleum resin was placed in a heating chamber and dissolved, and rotated for 10 minutes using an SC4-18 rotor at the corresponding temperature (MV 180: 180°C, MV 200: 200°C), and the stable value was measured.

[0150] (5) Aroma (%)

[0151] The resin was dissolved in a solvent CDCl3 at a concentration of 2.5 wt %, and then 1 H-NMR analysis (600 MHz). As shown in the following formula 1, the aromaticity (%) is calculated from the ratio of the number of protons in the aromatic region to the total number of hydrogen (protons) in the polymer.

[0152] [Formula 1]

[0153]

[0154] In formula 1, Ar A is the number of protons obtained from the peak area ratio of aromatic hydrocarbon-bonded hydrogen appearing in the aromatic region (specifically, the 6.0 ppm to 9.0 ppm region), O A is the number of protons obtained from the area ratio of the hydrogen peak appearing in the olefin region (specifically, the 4.0 ppm to 6.0 ppm region), Al A It is the number of protons obtained from the peak area ratio of hydrogen bonded to aliphatic hydrocarbons appearing in the aliphatic region (specifically, the region of 0.1 ppm to 4.0 ppm).

[0155] (6) Glass transition temperature (Tg, °C)

[0156] The glass transition temperature was measured using differential scanning calorimetry (DSC) at a heating rate of 5°C / min in the range of 0°C to 150°C.

[0157]

Table 1

[0158]

[0159]

[0160] <Preparation of Rubber Composition for Tire Tread>

[0161] Examples 2-1 to 2-10 and Comparative Examples 2-1 to 2-3

[0162] The following components were added and mixed in a brabender mixer to prepare each rubber composition for tire tread:

[0163] 84.60 g of styrene-butadiene rubber (SBR, Kumho Petrochemical, Co., Ltd., 5251H) and 28.20 g of neodymium butadiene rubber (Kumho Petrochemical, Co., Ltd., NdBR40) as raw rubber;

[0164] 112.87 g of silica (EVONIK, Ultrasil VN3 GR) and 5.64 g of carbon black (OEC, N220) as fillers;

[0165] 11.29 g bis(3-(triethoxysilyl)propyl)tetrasulfide (TESPT, EVONIK, Si-69) as a silane coupling agent;

[0166] 1.69 g N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) as an antioxidant;

[0167] 2.11 g 1,3-diphenylguanidine (DPG) and 1.47 g N-cyclohexyl-2-benzothiazolesulfenamide (CBTS) as vulcanization accelerators;

[0168] 3.39 g ZnO and 2.26 g stearic acid as vulcanization accelerators;

[0169] 1.58 g sulfur as a vulcanizing agent;

[0170] 19.75 g of treated distillate aromatic extract (TDAE) and 1.13 g of wax as a softener; and

[0171] 22.57 g of petroleum resin as shown in Table 2 below.

[0172] Comparative Examples 2-4

[0173] The raw materials were added in the same mixing ratio as in Examples 2-1 to 2-10 and Comparative Examples 2-1 to 2-2, but without adding petroleum resin, and 42.32 g of TDAE and 1.13 g of wax were used as a softener to prepare a rubber composition for tire tread.

[0174]

Table 2

[0175]

[0176] Experimental Example 2: Evaluation of physical properties of tire tread compositions

[0177] Using each of the rubber compositions for tire treads of Examples 2-1 to 2-10 and Comparative Examples 2-1 to 2-3, each rubber sample was prepared according to the following method, and the wet grip and rolling resistance were measured.

[0178] (1) Preparation of rubber samples

[0179] Compounding was performed to prepare a rubber composition for tire tread, and then vulcanization was performed at 160° C. for about 20 minutes to prepare each rubber sample for testing. The t90 value of MDR (Moving Die Rheometer) was used as the vulcanization time.

[0180] (2) Measurement of physical properties

[0181] For each rubber sample prepared above, the loss factor (Tanδ) related to wet grip and rolling resistance was measured at 10 Hz in the temperature range of -80°C to 110°C using a dynamic mechanical analyzer (model: TA-DMA Q800). In this regard, the relative loss factors of the embodiments and comparative examples were calculated based on the result value (100) of Comparative Examples 2-3. The results are as follows: Figure 1 and Figure 2 shown.

[0182] Tan 0℃ is related to wet grip, and higher values ​​indicate better braking force. Tan 70℃ is related to rolling resistance characteristics, and lower values ​​indicate less rolling resistance, indicating higher fuel efficiency. Figure 2 For convenience, the reciprocal of Tan70℃ is taken. Figure 2 In the equation, higher values ​​indicate lower rolling resistance.

[0183] See also Figure 1 and Figure 2 It was found that the rubber compositions for tire treads of Examples 2-1 to 2-10 were superior in both braking and rolling resistance characteristics compared with Comparative Examples 2-1 and 2-2 using non-hydrogenated petroleum resins and Comparative Example 2-4 including TDAE as a softener.

[0184] In addition, referring to Comparative Example 2-3, it was found that when a hydrogenated petroleum resin with an aromaticity greater than 15% was used, although the monomer composition was similar to that in the embodiment, the braking force and rolling resistance performance of the tire tread composition were reduced, and the braking performance was poor compared with Comparative Example 2-2 and Comparative Example 2-3 using non-hydrogenated petroleum resin.

[0185] These results indicate that a hydrogenated petroleum resin having an aromaticity of 15% or less obtained from a monomer mixture comprising dicyclopentadiene, an aromatic vinyl monomer, and optionally an olefin monomer can be used in a rubber composition for tire treads to improve both braking performance and fuel efficiency.

Claims

1. A hydrogenated petroleum resin obtained by polymerization and hydrogenation of a monomer mixture comprising the following components: Dicyclopentadiene; Aromatic vinyl monomers; and optional olefin monomers, in, The aromaticity of the hydrogenated petroleum resin is less than 15%.

2. The hydrogenated petroleum resin according to claim 1, wherein The content of the aromatic vinyl monomer in 100 parts by weight of the monomer mixture is 10 parts by weight to 30 parts by weight.

3. The hydrogenated petroleum resin according to claim 1 or 2, wherein The content of the olefin monomer in 100 parts by weight of the monomer mixture is 0 parts by weight to 20 parts by weight.

4. The hydrogenated petroleum resin according to claim 1, wherein 100 parts by weight of the monomer mixture consists of the following: 20 to 30 parts by weight of the aromatic vinyl monomer; 0 to 15 parts by weight of the olefin monomer; and The remainder is dicyclopentadiene.

5. The hydrogenated petroleum resin according to any one of claims 1 to 4, wherein The aroma level ranges from 5% to 14.5%.

6. The hydrogenated petroleum resin according to any one of claims 1 to 5, wherein The weight average molecular weight is 500 g / mol to 1,000 g / mol.

7. The hydrogenated petroleum resin according to any one of claims 1 to 6, wherein The aromatic vinyl monomer is one or more selected from styrene, α-methylstyrene, p-methylstyrene, indene, methylindene and vinyltoluene.

8. The hydrogenated petroleum resin according to any one of claims 1 to 7, wherein The olefin monomer is one or more selected from piperylene, isoprene, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene and 1-hexadecene.

9. A rubber composition for tire tread, comprising: Raw rubber; as well as The hydrogenated petroleum resin according to any one of claims 1 to 8.

10. The rubber composition for tire tread according to claim 9, wherein The content of the hydrogenated petroleum resin is 10 parts by weight to 50 parts by weight relative to 100 parts by weight of the raw rubber.

11. The rubber composition for tire tread according to claim 9 or 10, further comprising one or more selected from the group consisting of a filler, an activator, an antioxidant, a vulcanizing agent and a vulcanization accelerator.

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