Hydrogenated petroleum resin and rubber composition for tire tread containing same

Abstract

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

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0102534, filed on August 17, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a hydrogenated petroleum resin and a rubber composition for a tire tread containing the same. [Background technology]

[0003] A tire's energy consumption efficiency is determined by measuring its rolling resistance (RR) and wet grip. Rolling resistance refers to the energy loss between the tire and the road surface while driving, and the lower the rolling resistance, the better the fuel efficiency. Wet grip relates to braking performance on wet roads, such as in the rain, and is related to safety.

[0004] One of the main challenges in tire development is improving fuel economy by reducing rolling resistance. However, there is a trade-off between rolling resistance and braking force, and reducing rolling resistance can lead to a decrease in braking performance.

[0005] Rubber compositions for tire treads are composed of raw rubber, fillers, and other additives, and their physical properties can be adjusted by changing the types of raw materials or by varying the composition. Therefore, efforts are ongoing to develop rubber compositions for tire treads that have an appropriate balance of required physical properties. Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a hydrogenated petroleum resin capable of simultaneously improving the braking characteristics and rolling resistance characteristics of a rubber composition for a tire tread, and a tire tread composition containing the same. [Means for solving the problem]

[0007] In order to solve the above problem, according to one embodiment of the present invention, Provided is a hydrogenated petroleum resin obtained by polymerization and hydrogenation of a monomer mixture containing dicyclopentadiene; an aromatic vinyl monomer; and optionally, an olefinic monomer, the hydrogenated petroleum resin having an aromatization degree of 15% or less.

[0008] According to another embodiment of the present invention, there is provided a rubber composition for a tire tread, which comprises the hydrogenated petroleum resin. [Effects of the Invention]

[0009] The hydrogenated petroleum resin of the present invention has excellent compatibility with rubber and can be used in rubber compositions for tire treads to maximize braking performance without significantly increasing rolling resistance. Therefore, rubber compositions for tire treads containing the hydrogenated petroleum resin have excellent braking power and fuel efficiency, and can be suitably used in the manufacture of high-quality tires. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows the results of a wet road braking force test (Tan 0° C.) for the rubber compositions for tire treads of Examples and Comparative Examples. [Figure 2] FIG. 2 shows the rolling resistance test results (Tan 70° C., shown in reciprocal) of the rubber compositions for tire treads of Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0011] As used herein, the term "petroleum resin" refers to a resin polymerized using dicyclopentadiene as a monomer, specifically a resin polymerized from a monomer mixture containing dicyclopentadiene, an aromatic vinyl monomer, and optionally, an olefin monomer. Furthermore, the term "hydrogenated petroleum resin" refers to a resin obtained by subjecting the petroleum resin to a hydrogenation reaction, i.e., a hydrogenation reaction.

[0012] The term "hydrogenation" or "hydrogenation reaction" refers to a reaction in which hydrogen is added to an unsaturated bond such as a double bond to convert it into a single bond.

[0013] The term "monomer mixture" refers to a group of monomers that does not contain a solvent or additives, and the term "monomer composition" refers to the monomer mixture dispersed in a solvent, which may further contain an initiator and other additives.

[0014] In the present invention, terms such as first and second are used to describe various components, and the terms are used only to distinguish one component from another.

[0015] Furthermore, the terms used in this specification are merely used to describe exemplary embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly dictates otherwise. It should be understood that, in this specification, the terms "comprise," "include," "comprise," "have," and the like are intended to specify the presence of implemented features, steps, components, or combinations thereof, and do not preclude the possibility of the presence or addition of one or more other features, steps, components, or combinations thereof.

[0016] Although the present invention can be embodied in various forms through various modifications, specific embodiments are described in detail below by way of example, but it should be understood that this is not intended to limit the present invention to the specific disclosed embodiments, and that the present invention encompasses all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0017] The hydrogenated petroleum resin of the present invention and the rubber composition for tire tread containing the same will be described in more detail below.

[0018] Hydrogenated petroleum resin The hydrogenated petroleum resin of the present invention is obtained by polymerization and hydrogenation of a monomer mixture containing dicyclopentadiene, an aromatic vinyl monomer, and optionally, an olefinic monomer, and has an aromatization degree of 15% or less.

[0019] The hydrogenated petroleum resin has excellent compatibility with raw rubber contained in a rubber composition for a tire tread, and is suitable for inclusion as an additive for imparting tackiness, thereby improving the braking performance of the tire tread composition while minimizing a decrease in fuel efficiency.

[0020] The aromatic vinyl monomer may have 6 to 20 carbon atoms, and specifically, one or more selected from the group consisting of styrene, alpha-methylstyrene, para-methylstyrene, indene, methylindene, and vinyltoluene can be used as the aromatic vinyl monomer.

[0021] The olefin monomer may have 2 to 20 carbon atoms, and specifically may be one or more selected from the group consisting of 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.

[0022] In one embodiment, the aromatic vinyl monomer may be styrene, and the olefin monomer may be piperylene.

[0023] The dicyclopentadiene is used as a main monomer, and specifically, may be contained in an amount of 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, based on 100 parts by weight of the monomer mixture.

[0024] The aromatic vinyl monomer may be contained in an amount of 10 parts by weight or more, or 20 parts by weight or more and 30 parts by weight or less, based on 100 parts by weight of the monomer mixture. When the content of the aromatic vinyl monomer satisfies this range, excellent compatibility with the raw rubber contained in the rubber composition for tire treads and excellent adhesion properties can be achieved.

[0025] The olefinic monomer is an optional comonomer, and may be contained in an amount of 0 to 20 parts by weight per 100 parts by weight of the monomer mixture, or may be contained in an amount of 0 part by weight or more, 0.7 parts by weight or more, or 1 part by weight or more and 15 parts by weight or less, or 10 parts by weight or less. From the viewpoint of compatibility with the raw rubber, it is preferable that the content of the olefinic monomer is 20 parts by weight or less per 100 parts by weight of the monomer mixture.

[0026] The remainder of 100 parts by weight of the monomer mixture, excluding the aromatic vinyl monomer and the olefin monomer, may be dicyclopentadiene. That is, the monomer mixture may contain dicyclopentadiene, the aromatic vinyl monomer, and the optionally contained olefin monomer, but may not further contain any other comonomer.

[0027] Specifically, 100 parts by weight of the monomer mixture may consist of 10 to 30 parts by weight of an aromatic vinyl monomer; 0 to 20 parts by weight of an olefin monomer; and the remainder being dicyclopentadiene.

[0028] Alternatively, 100 parts by weight of the monomer mixture may consist of 20 to 30 parts by weight of an aromatic vinyl monomer; 0 to 15 parts by weight of an olefin monomer; and the remainder being dicyclopentadiene.

[0029] Alternatively, 100 parts by weight of the monomer mixture may consist of 20 to 30 parts by weight of an aromatic vinyl monomer; 0.7 to 15 parts by weight of an olefin monomer; and the remainder dicyclopentadiene.

[0030] Alternatively, 100 parts by weight of the monomer mixture may consist of 20 to 30 parts by weight of an aromatic vinyl monomer; 0.7 to 10 parts by weight of an olefin monomer; and the remainder dicyclopentadiene.

[0031] The hydrogenated petroleum resin according to one embodiment of the present invention satisfies the above-mentioned monomer composition and also has a degree of aromatization of 15% or less, and exhibits excellent compatibility with the raw rubber contained in the tire tread composition. The degree of aromatization is the content of aromatic double bonds in the petroleum resin and can be measured by NMR analysis, and a specific measurement method will be described in the following experimental examples.

[0032] To ensure the above effects, the degree of aromatization of the hydrogenated petroleum resin is 15% or less, or 14.5% or less, and more preferably 3% or more, 5% or more, 6% or more, or 6.5% or more from the viewpoint of improving the braking properties and rolling resistance properties of the tire tread composition. If the degree of aromatization of the hydrogenated petroleum resin exceeds 15%, compatibility with the raw rubber decreases, resulting in a decrease in braking properties or rolling resistance properties, so it is preferable to satisfy the above range.

[0033] Meanwhile, the hydrogenated petroleum resin preferably has a weight-average molecular weight of 500 g / mol or more, 600 g / mol or more, or 650 g / mol or more, and 1,000 g / mol or less, 950 g / mol or less, or 900 g / mol or less. When the weight-average molecular weight of the hydrogenated petroleum resin satisfies the above range, it is preferable because it exhibits excellent rolling resistance characteristics and improved braking characteristics.

[0034] The hydrogenated petroleum resin may have a molecular weight distribution (PDI) 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 exhibits narrow molecular weight distribution and uniform physical properties.

[0035] 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 explained in the following experimental examples.

[0036] The softening point of the hydrogenated petroleum resin may be 90°C or higher, or 95°C or higher, and 120°C or lower, 115°C or lower, or 110°C or lower. If the softening point of the hydrogenated petroleum resin is too high or too low, compatibility with the raw rubber may decrease, resulting in a problem of bias toward only one of rolling resistance characteristics or braking characteristics. Therefore, it is preferable that the softening point satisfies the above range.

[0037] The hydrogenated petroleum resin exhibits excellent physical properties with a heat loss of 3.0% or less, preferably 2.8% or less, or 2.7% or less. The lower the heat loss, the better, and theoretically it can be 0%.

[0038] The hydrogenated petroleum resin is obtained by polymerization and hydrogenation of the above-mentioned monomer mixture. Specifically, the hydrogenated petroleum resin can be produced by a production method including the steps of thermally polymerizing a monomer mixture containing dicyclopentadiene, an aromatic vinyl monomer, and optionally an olefin monomer to produce a petroleum resin, and hydrogenating the petroleum resin. The degree of aromatization of the hydrogenated petroleum resin can be adjusted depending on the content ratio of the reactants, reaction conditions, hydrogenation conditions, etc. during the production of the petroleum resin.

[0039] The monomer mixture can be introduced into the thermal polymerization reaction in a state where it is dispersed in a solvent, that is, as a monomer composition.

[0040] The solvent that can be used in producing the monomer composition is not particularly limited, and for example, one or more solvents selected from the group consisting of pentane, hexane, heptane, nonane, decane, benzene, toluene, and xylene can be used.

[0041] The monomer composition may further contain additives commonly used in the technical field of the present invention, such as an antioxidant and a polymerization inhibitor.

[0042] The method for thermally polymerizing the monomer mixture is not particularly limited, but for example, it can be prepared by a) a first-stage polymerization in which the monomer mixture is thermally polymerized in a continuous stirred tank reactor (CSTR), and b) a second-stage polymerization in which the reaction product of the first-stage polymerization is thermally polymerized in a plug flow reactor (PFR). In this case, as described above, the monomer mixture can be used in the form of a monomer composition dissolved in a solvent.

[0043] When thermal polymerization is carried out in two stages as described above, the heat of the polymerization reaction can be easily controlled, the monomer conversion rate or polymerization rate is significantly improved, and a petroleum resin having a narrow molecular weight distribution and uniform physical properties can be provided.

[0044] The reaction temperature (T1) in step 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 side reactions such as crosslinking reactions can be suppressed.

[0045] The reaction pressure in step a) may be 1 to 40 bar, 5 to 35 bar, or 10 to 30 bar. When the reaction is carried out under the above reaction pressure, the reactivity of the monomer can be increased to a level that does not pose a safety risk.

[0046] The reaction time in step a) may be 10 to 90 minutes, 20 to 80 minutes, or 30 to 70 minutes. If the reaction time is too short, side reactions caused by mixing of raw materials may not be sufficiently suppressed, and if the reaction time is too long, the productivity of the final resin may be low and the molecular weight distribution may be broad. From this perspective, it is preferable to adjust the reaction time within the above range.

[0047] The reaction temperature (T2) in step b) may be within ±30°C of the reaction temperature (T1) in step a), i.e., T1-30°C to T1+30°C, T1-20°C to T1+20°C, or T1-15°C to T1+15°C. When the reaction is carried out at the above reaction temperatures, side reactions can be suppressed and productivity can be increased.

[0048] In addition, by controlling the temperature difference between step a) and step b) within ±30°C, it is possible to minimize the generation of unreacted oligomers and produce a dicyclopentadiene-based resin with a narrow molecular weight distribution.

[0049] The reaction pressure in step b) may be 1 to 40 bar, 5 to 35 bar, or 10 to 30 bar. If the reaction pressure is too low, the reactivity is low due to vaporized monomers, and if the pressure is too high, there is a high risk of a safety accident occurring during the process. From this perspective, it is preferable to adjust the reaction pressure within the above range.

[0050] The reaction time in step b) may be 1 to 4 times, 1 to 3 times, or 1 to 2 times the reaction time in step a). If the reaction time is too short compared to the reaction time in the polymerization of step a), the reaction may not proceed sufficiently, whereas if the reaction time is too long, side reactions may occur. From this perspective, it is preferable to adjust the reaction time within the above range.

[0051] In addition, the internal volume of the PFR used in the polymerization of step b) may be 1 to 3 times, 1 to 2.5 times, or 1 to 2 times the internal volume of the CSTR used in the polymerization of step a). If the internal volume of the PFR is too small compared to the internal volume of the CSTR, the polymerization in the PFR may not proceed sufficiently, resulting in a large amount of impurities such as wax remaining. On the other hand, if the internal volume of the PFR is too large compared to the internal volume of the CSTR, the application effect of the CSTR reactor may be limited and control of the initial reaction heat may be insufficient, making it difficult to control the reaction temperature. From this perspective, it is preferable to adjust the internal volume of the PFR to the above-mentioned range.

[0052] The hydrogenation reaction is not particularly limited and may be carried out by a method known in the art. The hydrogenation reaction is a reaction in which hydrogen is added to an unsaturated bond such as a double bond to convert it into a single bond, and a hydrogenated petroleum resin can be obtained from the petroleum resin by the hydrogenation reaction.

[0053] The hydrogenation reaction can be carried out by a method known in the art to which the present invention pertains. For example, the obtained petroleum resin can be hydrogenated by being introduced into a continuous hydrogenation reactor packed with a hydrogenation catalyst.

[0054] The hydrogenation catalyst is not particularly limited, and any known hydrogenation catalyst can be used. Specific examples include one or more selected from the group consisting of Ni, Fe, Cu, Co, Mo, Pd, Rh, Pt, Nb, Au, Rd, and Raney Ni.

[0055] To improve reactivity, the hydrogenation catalyst may be used in an amount of 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 part by weight or less, per 100 parts by weight of the petroleum resin, but is not limited thereto.

[0056] The conditions for the hydrogenation reaction are not particularly limited and can be appropriately adjusted depending on the type and amount of catalyst used, the amount of hydrogen added, etc. For example, the hydrogenation reaction can be carried out at a pressure of 50 to 150 bar and a temperature range of 150 to 300° C. When the hydrogenation reaction is carried out at such pressure and temperature, destruction of the molecular structure can be prevented.

[0057] Also, hydrogen gas can be continuously introduced during the hydrogenation reaction so that the reaction pressure is maintained constant.

[0058] The hydrogenation reaction may be carried out once under the above conditions, or may be carried out twice or more times to achieve the desired degree of aromatization. When the hydrogenation reaction is carried out twice or more times, the conditions for each reaction may be the same or different.

[0059] The hydrogenated petroleum resin produced by the above method has excellent compatibility with the raw rubber used in the tire tread composition, and its high adhesive performance can improve the braking characteristics of the tire tread composition while minimizing an increase in rolling resistance. Therefore, the hydrogenated petroleum resin can be useful as a tackifying resin in the tire tread composition.

[0060] Rubber composition for tire tread The rubber composition for tire treads of the present invention contains raw rubber and the above-mentioned hydrogenated petroleum resin, and thereby exhibits high braking performance and fuel efficiency.

[0061] The hydrogenated petroleum resin is contained in a rubber composition for tire treads to further improve adhesion between rubbers and improve the mixability, dispersibility, and processability of fillers and other additives, thereby improving the physical properties of the rubber composition.

[0062] In particular, the hydrogenated petroleum resin satisfies the above-mentioned monomer composition and aromaticity, thereby exhibiting excellent compatibility with raw rubber and additives, and providing improved braking performance through excellent adhesion while minimizing an increase in rolling resistance.

[0063] The raw rubber is not particularly limited as long as it has an olefinic double bond (carbon-carbon double bond), and natural rubber, synthetic rubber, or a mixture of these can be used.

[0064] As an example, the raw rubber may be one or more selected from the group consisting of 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-p-methylstyrene rubber.

[0065] In one embodiment, the rubber composition for tire treads may contain the 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, 40 parts by weight or less, or 30 parts by weight or less, per 100 parts by weight of raw rubber. If the amount of hydrogenated petroleum resin is less than 10 parts by weight per 100 parts by weight of raw rubber, it may be difficult to ensure dispersibility, processability, and braking properties. If the amount exceeds 50 parts by weight, the braking properties may be excellent, but the rolling resistance may become excessively high.

[0066] The rubber composition for a tire tread may further include one or more selected from the group consisting of a filler, a silane coupling agent, an antioxidant, a softener, a vulcanizing agent, a vulcanization accelerator, and a vulcanization acceleration aid.

[0067] The filler is added to increase the durability and heat resistance of the tire and to improve chipping resistance, cutting resistance, abrasion resistance, etc., and for example, carbon black and / or silica can be used.

[0068] The carbon black has a nitrogen surface area per gram (N2SA) of 30 to 300 m 2 / g, and the DBP (n-dibutyl phthalate) oil absorption may be 60 to 180 cc / 100 g.

[0069] The carbon black has a nitrogen adsorption specific surface area of ​​300m 2 If it exceeds 30m / g, the processability of the rubber composition for tires becomes poor. 2 If the DBP oil absorption of the carbon black is less than 180 cc / 100 g, the processability of the rubber composition may be reduced, and if the DBP oil absorption is less than 60 cc / 100 g, the reinforcing performance of the carbon black filler may be reduced.

[0070] The carbon black may be contained in an amount of 1 to 50 parts by weight, or 5 to 30 parts by weight, per 100 parts by weight of the raw rubber. If the carbon black content is less than 1 part by weight, the reinforcing performance of the carbon black filler may be reduced, and if it exceeds 50 parts by weight, the processability of the rubber composition may be impaired.

[0071] The silica has a nitrogen surface area per gram (N2SA) of 100 to 180 m 2 / g, and the CTAB (cetyl trimethyl ammonium bromide) adsorption specific surface area is 110~170m 2 / g, but the present invention is not limited thereto.

[0072] The nitrogen adsorption specific surface area of ​​the silica is 100m 2 If it is less than 180m / g, the reinforcing performance of the silica filler will be impaired. 2 If the CTAB adsorption specific surface area of ​​the silica is more than 110 m / g, the processability of the rubber composition may be adversely affected. 2If it is less than 170m / g, the reinforcing performance of the silica filler will be impaired. 2 If it exceeds 1 / g, the processability of the rubber composition may be adversely affected.

[0073] The silica may be contained in an amount of 10 to 150 parts by weight, preferably 50 to 100 parts by weight, per 100 parts by weight of the raw rubber. If the silica content is less than 10 parts by weight, the improvement in rubber strength may be insufficient, and the fuel economy performance of the tire may decrease, whereas if the silica content exceeds 150 parts by weight, the wear performance may decrease.

[0074] Meanwhile, when using the silica, a silane coupling agent may be further included for blending the silica. Examples of the silane coupling agent include vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, bis(3-(triethoxysilyl)propyl)disulfide, bis(3-triethoxysilyl)propyl)disulfide, and the like. silylpropyl) trisulfide, bis(3-(triethoxysilyl)propyl) tetrasulfide, bis(2-triethoxysilylethyl) tetrasulfide, bis(3-trimethoxysilylpropyl) tetrasulfide, bis(2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethy Examples of suitable silyl tetrasulfide include 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl benzothiazolyl tetrasulfide, 3-triethoxysilylpropyl benzolyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis(3-diethoxymethylsilylpropyl)tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, and dimethoxymethylsilylpropyl benzothiazolyl tetrasulfide. These may be used alone or in combination of two or more. Preferably, bis(3-(triethoxysilyl)propyl)tetrasulfide can be used.

[0075] The silane coupling agent may be included in an amount of 1 to 15 parts by weight, or 5 to 10 parts by weight, per 100 parts by weight of the raw rubber to improve the dispersibility of the silica. If the content of the silane coupling agent is less than 1 part by weight, the improvement in the dispersibility of the silica may be insufficient, resulting in a decrease in the processability of the rubber or a decrease in fuel economy. If the content exceeds 20 parts by weight, the interaction between the silica and the rubber may be too strong, resulting in excellent fuel economy but a significant decrease in braking performance.

[0076] The antioxidant is an additive used to stop the chain reaction of autoxidation of tires caused by oxygen. The antioxidant can be any one selected from the group consisting of amine-based, phenol-based, quinoline-based, imidazole-based, carbamic acid metal salt, wax, and combinations thereof.

[0077] The amine-based antioxidant may be any one selected from the group consisting of 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 antioxidant may be any one selected from the group consisting of phenols such as 2,2'-methylene-bis(4-methyl-6-tert-butylphenol), 2,2'-isobutylidene-bis(4,6-dimethylphenol), 2,6-di-t-butyl-p-cresol, and combinations thereof. The quinoline antioxidant may be 2,2,4-trimethyl-1,2-dihydroquinoline or a derivative thereof, specifically, 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, or a combination thereof. The wax may preferably be a waxy hydrocarbon.

[0078] The antioxidant may be included in an amount of 1 to 10 parts by weight per 100 parts by weight of the raw rubber, taking into consideration factors such as anti-aging properties, high solubility in rubber, low volatility, inertness to rubber, and not inhibiting vulcanization.

[0079] The softener is added to impart plasticity to rubber to facilitate processing or to reduce the hardness of vulcanized rubber, and can be a petroleum oil, vegetable oil, or a combination thereof. Specifically, the softener can be TDAE (treated distillate aromatic extracts) oil, MES (mild extraction solvate) oil, RAE (residual aromatic extract) oil, or heavy naphthenic oil, and preferably TDAE oil.

[0080] The softener is preferably used in an amount of 0 to 20 parts by weight per 100 parts by weight of the raw rubber from the standpoint of processability.

[0081] The vulcanizing agent is preferably a sulfur-based vulcanizing agent. Examples of the sulfur-based vulcanizing agent include inorganic vulcanizing agents such as powdered sulfur (S), insoluble sulfur (S), precipitated sulfur (S), and colloidal sulfur. Examples of the sulfur-based vulcanizing agent include elemental sulfur and sulfur-producing vulcanizing agents such as amine disulfide and polymeric sulfur.

[0082] The vulcanizing agent is preferably contained in an amount of 0.5 parts by weight or more, or 1.0 part by weight or more and 4.0 parts by weight or less, or 3.0 parts by weight or less, per 100 parts by weight of the raw rubber, in order to ensure an appropriate vulcanization effect and to ensure the stability of the raw rubber.

[0083] The vulcanization accelerator is an accelerator that accelerates the vulcanization rate and promotes a retarding effect at the initial vulcanization stage.

[0084] Examples of the vulcanization accelerator include thiuram accelerators such as trimethylthiuram monosulfide, tetramethylthiuram disulfide, and tetraethylthiuram disulfide; thiazole accelerators such as 2-mercaptobenzothiazole and dibenzothiazyl disulfide; sulfenamide accelerators such as N-cyclohexyl-2-benzothiazylsulfenamide and N-oxydiethylene-2-benzothiazolylsulfenamide; aldehyde-amine accelerators such as n-butylaldehyde-aniline condensation products and butyraldehyde-monobutylamine condensation products; aldehyde-ammonia accelerators such as hexamethylenetetramine; thiourea accelerators such as thiocarbanilide; and guanidine accelerators such as 1,3-diphenylguanidine. When these vulcanization accelerators are used, one type may be used alone, or two or more types may be used in combination. As an example, 1,3-diphenylguanidine (DPG) and N-cyclohexyl-2-benzothiazylsulfenamide (CBTS) can be used as the vulcanization accelerator.

[0085] The vulcanization accelerator is preferably used in an amount of 0.1 to 10 parts by weight per 100 parts by weight of raw rubber from the viewpoint of improving physical properties.

[0086] The vulcanization-accelerating coagent is used in combination with the vulcanization accelerator to further improve the accelerating effect.

[0087] Examples of the vulcanization accelerator aid 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 dimethacrylate, diallyl phthalate, N,Nm-phenylenedimaleimide, triallyl isocyanurate, trimethylolpropane trimethacrylate, etc. When these vulcanization accelerators are used, one type may be used alone, or two or more types may be used in combination.

[0088] The vulcanization accelerator is preferably used in an amount of 0.1 to 10 parts by weight per 100 parts by weight of raw rubber from the viewpoint of improving physical properties.

[0089] Meanwhile, the rubber composition for tire tread may further contain various additives used in the rubber industry, such as a vulcanization retarder, a peptizer, a process oil, a plasticizer, and the like.

[0090] The rubber composition for a tire tread can be prepared by kneading the above-mentioned components using a kneading machine such as a plastomill, a Banbury mixer, a roll, or an internal mixer.

[0091] The rubber composition for a tire tread prepared by the above method can be used as a material for constituting the tread portion (and the cap portion including the tread portion) that comes into contact with the road surface, and can also be used for various rubber components constituting a tire, such as a sidewall, a sidewall insert, an apex, a chafer, a wire coat, or an inner liner.

[0092] A tire manufactured using the rubber composition for tire tread has high gripping properties, excellent running stability and braking performance, and low rolling resistance, and can be suitably used as a fuel-efficient and high-performance tire.

[0093] The functions and effects of the present invention will be described in more detail below through specific examples of the present invention, but these examples are presented only as examples of the present invention and do not define the scope of the invention. [Example]

[0094] <Production of hydrogenated petroleum resin> Example 1-1 A monomer composition was prepared by mixing 693 g of dicyclopentadiene, 300 g of styrene, and 7 g of piperylene in 1,000 g of xylene solvent. The monomer composition was continuously fed into a continuous stirred tank reactor (CSTR) with an internal volume of 0.416 L and reacted with stirring at a temperature of 265°C and a pressure of 25 bar for 42 minutes to produce a primary polymer.

[0095] The primary polymer was continuously fed to a plug flow reactor (PFR) with an internal volume of 0.590 L, which was connected to the continuous stirred tank reactor, and polymerized for 63 minutes at a temperature of 277°C and a pressure of 25 bar. The polymerized product was then depressurized at 200°C for 30 minutes to recover the petroleum resin.

[0096] A hydrogenation reaction was carried out three times under the conditions of a temperature of 260° C. and a pressure of 100 bar using 0.5 wt % of a palladium catalyst and a hydrogen amount of 4 NL / min based on the total weight of the petroleum resin, to produce a hydrogenated petroleum resin.

[0097] Example 1-2 A hydrogenated petroleum resin was produced using the same production method as in Example 1-1, except that the petroleum resin was subjected to a hydrogenation reaction once.

[0098] Examples 1-3 A monomer composition was prepared by mixing 800 g of dicyclopentadiene and 200 g of styrene in 1,000 g of xylene solvent. The monomer composition was polymerized in the same manner as in Example 1-1 to prepare a petroleum resin.

[0099] A hydrogenated petroleum resin was produced by carrying out a hydrogenation reaction twice under the conditions of a temperature of 260° C. and a pressure of 100 bar using 0.5 wt % of a palladium catalyst and a hydrogen amount of 4 NL / min based on the total weight of the petroleum resin.

[0100] Examples 1-4 A monomer composition was prepared by mixing 760 g of dicyclopentadiene, 200 g of styrene, and 40 g of piperylene in 1,000 g of xylene solvent. A hydrogenated petroleum resin was prepared using the monomer composition in the same manner as in Examples 1-3.

[0101] Examples 1-5 A monomer composition was prepared by mixing 730 g of dicyclopentadiene, 200 g of styrene, and 70 g of piperylene in 1,000 g of xylene solvent. A hydrogenated petroleum resin was prepared using the monomer composition in the same manner as in Examples 1-3.

[0102] Examples 1-6 A monomer composition was prepared by mixing 680 g of dicyclopentadiene, 200 g of styrene, and 120 g of piperylene in 1,000 g of xylene solvent. A hydrogenated petroleum resin was prepared using the monomer composition in the same manner as in Examples 1-3.

[0103] Examples 1-7 A monomer composition was prepared by mixing 750 g of dicyclopentadiene and 250 g of styrene with 1,000 g of xylene solvent. A hydrogenated petroleum resin was prepared using the monomer composition in the same manner as in Example 1-1.

[0104] Examples 1-8 A monomer composition was prepared by mixing 675 g of dicyclopentadiene, 250 g of styrene, and 75 g of piperylene in 1,000 g of xylene solvent. A hydrogenated petroleum resin was prepared using the monomer composition in the same manner as in Example 1-2.

[0105] Examples 1-9 A monomer composition was prepared by mixing 693 g of dicyclopentadiene, 300 g of styrene, and 7 g of piperylene in 1,000 g of xylene solvent. A hydrogenated petroleum resin was prepared using the monomer composition in the same manner as in Examples 1-3.

[0106] Examples 1-10 A monomer composition was prepared by mixing 693 g of dicyclopentadiene, 300 g of styrene, and 7 g of piperylene in 1,000 g of xylene solvent. The monomer composition was continuously fed into a continuous stirred tank reactor (CSTR) with an internal volume of 0.416 L and reacted with stirring at a temperature of 265°C and a pressure of 25 bar for 42 minutes to produce a primary polymer.

[0107] The primary polymer was continuously fed to a plug flow reactor (PFR) with an internal volume of 0.590 L, which was connected to the continuous stirred tank reactor, and polymerized for 63 minutes at a temperature of 272°C and a pressure of 25 bar. The polymerized product was then depressurized at 200°C for 30 minutes to recover the petroleum resin.

[0108] A hydrogenated petroleum resin was produced by carrying out a hydrogenation reaction twice under the conditions of a temperature of 260° C. and a pressure of 100 bar using 0.5 wt % of a palladium catalyst and a hydrogen amount of 4 NL / min based on the total weight of the petroleum resin.

[0109] Comparative Example 1-1 A monomer composition was prepared by mixing 805.1 g of dicyclopentadiene, 170 g of styrene, and 24.9 g of piperylene in 1,000 g of xylene solvent. The monomer composition was continuously fed into a continuous stirred tank reactor (CSTR) with an internal volume of 0.416 L and reacted with stirring at a temperature of 265°C and a pressure of 25 bar for 42 minutes to produce a primary polymer.

[0110] The primary polymer was continuously fed to a plug flow reactor (PFR) with an internal volume of 0.590 L, which was connected to the continuous stirred tank reactor, and polymerized for 63 minutes at a temperature of 277°C and a pressure of 25 bar. The polymerized product was then depressurized at 200°C for 30 minutes to recover the petroleum resin.

[0111] Comparative Example 1-2 A monomer composition was prepared by mixing 693 g of dicyclopentadiene, 300 g of styrene, and 7 g of piperylene in 1,000 g of xylene solvent. A petroleum resin was prepared using the monomer composition in the same manner as in Comparative Example 1-1.

[0112] Comparative Examples 1-3 A monomer composition was prepared by mixing 693 g of dicyclopentadiene, 300 g of styrene, and 7 g of piperylene in 1,000 g of xylene solvent. The monomer composition was continuously fed into a continuous stirred tank reactor (CSTR) with an internal volume of 0.416 L and reacted with stirring at a temperature of 265°C and a pressure of 25 bar for 42 minutes to produce a primary polymer.

[0113] The primary polymer was continuously fed to a plug flow reactor (PFR) with an internal volume of 0.590 L, which was connected to the continuous stirred tank reactor, and polymerized for 63 minutes at a temperature of 272°C and a pressure of 25 bar. The polymerized product was then depressurized at 200°C for 30 minutes to recover the petroleum resin.

[0114] A hydrogenated petroleum resin was produced by carrying out a single hydrogenation reaction under the conditions of a temperature of 250° C. and a pressure of 100 bar using 0.5 wt % of a palladium catalyst and a hydrogen amount of 4 NL / min based on the total weight of the petroleum resin.

[0115] Experimental Example 1: Evaluation of the physical properties of petroleum resin (1) Softening point (℃) The softening point was measured using the ring and ball softening method (ASTM E 28).

[0116] Specifically, petroleum resin was melted and poured into a circular mold, which was then placed in a beaker containing glycerin. A ball was then placed on the ring containing the petroleum resin, and the temperature was raised by 2.5°C per minute to measure the temperature (softening point) at which the resin melted and the ball fell.

[0117] (2) Weight-average molecular weight (Mw, g / mol) and molecular weight distribution (PDI) The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (PDI) were measured using gel permeation chromatography (GPC) (Infinity 1260) in terms of polystyrene. The molecular weight distribution was calculated by dividing the measured weight average molecular weight by the number average molecular weight.

[0118] The petroleum resin to be measured was dissolved in tetrahydrofuran to a concentration of 0.05 wt%, and 10 μl was injected into the GPC. Tetrahydrofuran was used as the mobile phase for GPC, and the flow rate was 1 mL / min. Analysis was performed at 35°C. The columns consisted of one Guard column and three columns connected in series: PL gel 5 μm 50A, PL gel 5 μm 100A, and Oligopore 300A. A refractive index detector (RID) was used as the detector, and measurements were performed at 35°C.

[0119] Twelve types of styrene standards were used: molecular weights (g / mol) 104, 118, 236, 580, 1480, 2340, 2970, 5030, 8450, 10850, 20650, and 24600.

[0120] (3)Heating loss (%) 3 g of petroleum resin was placed in a heat loss measuring device (AND MX-50) and heated at 180°C for 1 hour. The weight change before and after heating was converted into a percentage to calculate the heat loss.

[0121] (4) Melt viscosity (MV180 and MV200, cPs) The melt viscosity was measured according to ASTM D3236. 8 g of petroleum resin was placed in a heating chamber and melted, then rotated at the corresponding temperature (MV180: 180°C, MV200: 200°C) for 10 minutes using an SC4-18 spindle, and the stabilized value was measured.

[0122] (5) Aromaticity (%) The resin was dissolved in a solvent, CDCl3, to a concentration of 2.5 wt % and then subjected to H-NMR analysis (600 MHz). The aromaticity (%) was calculated from the ratio of the number of protons in the aromatic region to the total number of protons in the polymer, as shown in Equation 1 below.

[0123]

number

[0124] In the formula 1, Ar A is the number of protons found from the area ratio of hydrogen peaks bonded to aromatic hydrocarbons that appear in the aromatic region, specifically the 6.0 to 9.0 ppm region, and O A is the number of protons calculated from the area ratio of the hydrogen peak appearing in the olefin region, specifically the 4.0 to 6.0 ppm region, and Al A is the number of protons found from the area ratio of the hydrogen peak bonded to aliphatic hydrocarbons that appears in the aliphatic region, specifically the region of 0.1 to 4.0 ppm.

[0125] (6) Glass transition temperature (Tg, °C) The glass transition temperature was measured using DSC (Differential Scanning Calorimetry) in the range of 0°C to 150°C at a temperature rise rate of 5°C / min.

[0126] [Table 1]

[0127] <Production of Rubber Composition for Tire Tread> Examples 2-1 to 2-10 and Comparative Examples 2-1 to 2-3 As raw rubber, 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 fillers, 112.87 g of silica (Ultrasil VN3 GR from EVONIK) and 5.64 g of carbon black (N220 from OEC); 11.29 g of bis(3-(triethoxysilyl)propyl)tetrasulfide (TESPT, Si-69 from EVONIK) as a silane coupling agent; 1.69 g of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) as an antioxidant; as vulcanization accelerators, 2.11 g of 1,3-diphenylguanidine (DPG) and 1.47 g of N-cyclohexyl-2-benzothiazylsulfenamide (CBTS); 3.39 g of ZnO and 2.26 g of stearic acid as vulcanization accelerators; As a vulcanizing agent, 1.58 g of sulfur; As a softener, 19.75g of TDAE (Treated Distillate Aromatic Extracts), 1.13g of wax, and 22.57 g of the petroleum resin shown in Table 2 below was added, and compounded in a Brabender mixer to produce a rubber composition for tire treads.

[0128] Comparative Example 2-4 Rubber compositions for tire treads were produced using raw materials in the same compounding ratios as in Examples 2-1 to 2-10 and Comparative Examples 2-1 to 2-2, but without adding petroleum resin, and using 42.32 g of TDAE and 1.13 g of wax as softeners.

[0129] [Table 2]

[0130] Experimental Example 2: Evaluation of physical properties of tire tread composition Using each of the rubber compositions for tire treads of Examples 2-1 to 2-10 and Comparative Examples 2-1 to 2-3, rubber test pieces were produced by the following method, and the braking force on wet roads and rolling resistance were measured.

[0131] (1) Preparation of rubber test specimens After compounding to prepare a rubber composition for tire tread, the mixture was vulcanized at 160°C for about 20 minutes to prepare a rubber test piece. The vulcanization time was measured using the t90 value of a moving die rheometer (MDR).

[0132] (2) Measurement of physical properties The prepared rubber specimens were subjected to dynamic mechanical analysis (Model: TA-DMA Q800) to measure the wet grip and rolling resistance-related loss factor (Tan δ) at a temperature range of -80 to 110°C and 10 Hz. The relative loss factor values ​​of each example and comparative example were calculated using the results of Comparative Examples 2-3 as the reference (100), and the results are shown in Figures 1 and 2.

[0133] Tan0°C is related to braking force on wet roads, with a higher value indicating better braking force. Tan70°C is related to rolling resistance characteristics, with a lower value indicating lower rolling resistance and better fuel economy. However, Figure 2 shows the reciprocal of Tan70°C for better visibility, and in Figure 2, the higher the value, the lower the rolling resistance is judged to be.

[0134] 1 and 2, it can be seen that the rubber compositions for tire treads of Examples 2-1 to 2-10 have superior braking characteristics and rolling resistance characteristics compared to Comparative Examples 2-1 and 2-2, which used non-hydrogenated petroleum resin, and Comparative Example 2-4, which contained TDAE as a softener.

[0135] Furthermore, referring to Comparative Example 2-3, although the monomer composition is similar to that of the Examples, when a hydrogenated petroleum resin with an aromatization degree exceeding 15% is used, it can be confirmed that the braking force and rolling resistance characteristics of the tire tread composition all decrease, and the braking characteristics are worse than when a non-hydrogenated petroleum resin is used (Comparative Example 2-2 and Comparative Example 2-3).

[0136] From the above results, it can be confirmed that hydrogenated petroleum resins with an aromatization degree of 15% or less, obtained from a monomer mixture containing dicyclopentadiene, an aromatic vinyl monomer, and optionally an olefinic monomer, can be used in rubber compositions for tire treads to simultaneously improve braking characteristics and fuel efficiency.

Claims

1. Dicyclopentadiene; an aromatic vinyl monomer; and A hydrogenated petroleum resin obtained by polymerization and hydrogenation of a monomer mixture optionally containing an olefinic monomer, A hydrogenated petroleum resin having an aromatization degree of 15% or less.

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

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

4. 100 parts by weight of the monomer mixture 20 to 30 parts by weight of the aromatic vinyl monomer; 0 to 15 parts by weight of the olefinic monomer; and 2. The hydrogenated petroleum resin according to claim 1, wherein the balance is dicyclopentadiene.

5. The hydrogenated petroleum resin according to any one of claims 1 to 4, wherein the degree of aromatization is 5% to 14.5%.

6. The hydrogenated petroleum resin according to any one of claims 1 to 5, having a weight average molecular weight of 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 at least one selected from the group consisting of styrene, alpha-methylstyrene, para-methylstyrene, indene, methylindene, and vinyltoluene.

8. The hydrogenated petroleum resin according to any one of claims 1 to 7, wherein the olefin-based monomer is at least one selected from the group consisting of 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. raw rubber; and A rubber composition for tire treads, comprising the hydrogenated petroleum resin according to any one of claims 1 to 8.

10. 10. The rubber composition for tire treads according to claim 9, wherein the hydrogenated petroleum resin is contained in an amount of 10 to 50 parts by weight per 100 parts by weight of raw rubber.

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

Images