Rubber composition for pneumatic tires and pneumatic tires manufactured therefrom

Abstract

A rubber composition for pneumatic tires comprising a styrene-butadiene copolymer having a low glass transition temperature, and a blend of a hydrocarbon resin and one or more oils, and a pneumatic tire manufactured therefrom.

Description

[Technical Field]

[0001] This invention relates to a rubber composition for pneumatic tires, the use of the rubber composition in the manufacture of pneumatic tires, and pneumatic tires comprising or prepared from the rubber composition. Pneumatic tires are suitable for passenger-type motor vehicles. [Background technology]

[0002] Pneumatic tires for automobiles can be designed to perform well under specific conditions. For example, winter tires remain soft at low temperatures (e.g., below 7°C) to provide traction in snowy or icy conditions. Such tires are known, for example, from European Patent Application Publication No. 2 643 400(A1). They are not suitable for use in warmer temperatures because the soft compound wears down easily, shortening the tire's lifespan. Wet performance may also be reduced. Summer tires are designed to perform well in warm conditions and can improve cornering and braking capabilities while maintaining favorable conditions in wet conditions. This balance can be achieved by using a stiffer compound, i.e., a compound that softens at higher temperatures than winter tire compounds. However, grip at low temperatures is consequently reduced, and these tires are not suitable for winter conditions.

[0003] Manufacturing tires that perform well under all conditions is a particularly challenging task for tire designers. These tires must offer a long tread life while providing balanced performance suitable for a variety of driving conditions, including wet, dry, and winter conditions on various road surfaces. Achieving these objectives requires considering factors such as the tire's softening temperature (the glass transition temperature of the elastomer in the rubber compound (T)). gIt is necessary to balance parameters including the viscoelastic properties (indicated by the Payne effect and the ratio of the loss modulus to the storage modulus (tanδ)) and their viscoelastic properties. In particular, it can be difficult to prepare a tire that has good winter performance while maintaining good wet and dry performance. In such a tire, typically a low T is used to provide the necessary grip at low temperatures. g An elastomer having the following properties is used, and its use must be balanced with other factors (e.g., filler and resin / plasticizer filler amounts) to provide suitable performance in wet and dry conditions and a long tire life.

[0004] Resins, particularly hydrocarbon resins, are additives known to be used in rubber compositions for pneumatic tire treads. They can be used as processing aids to impart properties such as raw tackiness to rubber compositions. Tackiness is the ability of two materials to resist separation after brief contact under light pressure. Some degree of tackiness is necessary so that many components of a raw tire can be processed into a molded tire product. Furthermore, certain properties such as hardness, modulus of elasticity, and swelling properties may be influenced by the resin.

[0005] Compatibility between elastomers, resins, plasticizers, and fillers is necessary to maintain good processability with high resin filler content. Consequently, designers of pneumatic tires must carefully select the combination of these components that make up the rubber compound. For example, European Patent Application Publication 2643401(A1) describes mixing a resin with a liquid plasticizer to improve the processability of a rubber composition. However, there remains a need in the art to provide rubber compositions for pneumatic tires that maintain good processability while exhibiting balanced performance across various driving conditions, including good winter performance.

[0006] The present invention aims to provide solutions to one or more of the problems identified above. [Overview of the Initiative]

[0007] The inventors have discovered that pneumatic tires having an improved balance of wet / dry grip, dry handling, and processability while maintaining winter performance can be prepared from a rubber composition comprising a polymer containing heteroatom functional groups and a resin containing heteroatom functional groups. The interaction between the polymer functional groups and the resin functional groups does not adversely affect processability and is important for the desirable performance characteristics of the tire.

[0008] According to a first aspect of this invention, Glass transition temperature (T) of -90℃ to -30℃ g A copolymer of styrene and butadiene (SBR) having ) and containing a heteroatom functional group, Optionally, diene elastomer and T g A hydrocarbon resin containing a heteroatom functional group having, A rubber composition for pneumatic tires, comprising oil, The present invention relates to a rubber composition for pneumatic tires in which the total amount of the hydrocarbon resin and the oil is at least 40 phr.

[0009] According to a second aspect, the present invention relates to a pneumatic tire comprising the above-mentioned rubber composition.

[0010] According to a third aspect, the present invention relates to a pneumatic tire prepared from the above-mentioned rubber composition.

[0011] According to a fourth aspect, the present invention relates to the use of the above-mentioned rubber composition in the manufacture of a pneumatic tire.

[0012] Further advantageous features of the present invention are described in the following description, drawings, and dependent claims. [Modes for carrying out the invention]

[0013] The resin has a low T gWhen used in rubber compositions having polymer blends (i.e., <0°C), lower miscibility can be observed, which results in lower filler dispersion and higher stiffness, thus positively impacting the balance of wet / dry grip and dry handling while maintaining winter performance and avoiding adverse effects on processability. The inventors have discovered that using polymers and resins containing heteroatomic functional groups increases miscibility, resulting in an interaction effect that leads to an improvement in the balance of wet / dry grip and dry handling while maintaining winter performance and avoiding adverse effects on processability. The concept of resin miscibility may be beneficial in improving the wet / dry grip / dry handling balance, which is controlled by an increase in hysteresis loss between 0 and 30°C. As a result, the rubber compositions of the present invention are well suitable for producing pneumatic tires having these properties.

[0014] According to the above, in one embodiment, the present invention is Glass transition temperature (T) of -90℃ to -30℃ g A copolymer of styrene and butadiene (SBR) having ) and containing a heteroatom functional group, Optionally, diene elastomer and T g A hydrocarbon resin containing a heteroatom functional group having, A rubber composition for pneumatic tires, comprising oil, The present invention provides a rubber composition for pneumatic tires in which the total amount of the hydrocarbon resin and the oil is at least 40 phr.

[0015] Elastomer The copolymer of styrene and butadiene may be styrene-butadiene copolymer (abbreviated as SBR), emulsion SBR or eSBR (i.e., SBR prepared by emulsion polymerization), solution SBR or sSBR (i.e., SBR prepared by solution polymerization), or a mixture of both. The T of the copolymer of styrene and butadiene g is -75 °C to -40 °C, preferably -65 °C to -50 °C, and may be, for example, -65 °C, -60 °C, -55 °C, or -50 °C. Those skilled in the art recognize how to modify the structure of the copolymer to adjust T g to the required value. The copolymer of styrene and butadiene may be present in an amount of at least 50 phr, preferably 60 to 100 phr, more preferably 100 phr.

[0016] SBR may have a styrene content of 1 wt% to 20 wt% of SBR, more preferably 5 wt% to 15 wt% of SBR, for example, 5 wt%, 10 wt%, or 15 wt% of SBR. SBR may have a vinyl content of 20 wt% to 40 wt% of SBR, more preferably 28 wt% to 38 wt% of SBR, for example, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, or 38 wt% of SBR.

[0017] SBR may be functionalized with one or more functional groups. These functional groups may be terminal functional groups, pendant functional groups, or both terminal and pendant functional groups. Preferably, one or more functional groups may be selected from the group consisting of alcohol, carboxyl, ester, amide, amine, imine, imide, nitrile, oxime, thiol, sulfide, sulfoxide, sulfone, sulfinic acid, sulfonic acid, sulfonic acid ester, thiocarboxylic acid, thioester, silane, alkoxysilane, aminosilane, and silanol, and more preferably may be carboxyl or aminosilane.

[0018] In embodiments where SBR is functionalized with carboxyl groups, these groups are of formula (I):

[0019] [ka] (In the ceremony R1 and R2 are the same or different, and each is independently a hydrogen, alkyl, alkoxy, cycloalkyl, cycloalkoxy, aryl, aryloxy, alkylaryl, alkylaryloxy, aralkyl, or aralkoxy group, which may contain one or more heteroatoms, preferably one or more heteroatoms selected from the group consisting of O, N, S, and Si. R3 and R4 are the same or different, and each is independently a hydrogen, alkyl, cycloalkyl, aryl, alkaryl, or aralkyl group, which may contain one or more heteroatoms, preferably one or more heteroatoms selected from the group consisting of O, N, S, and Si. A is a divalent organic group which may be an alkyl group; one or more heteroatoms selected from the group consisting of O, NR7, S and SiR8R9; or an alkyl group which contains one or more heteroatoms, preferably one or more heteroatoms selected from the group consisting of O, NR7, S and SiR8R9, where R7 may be hydrogen, a C1-C6 linear alkyl group which is preferably methyl or trimethylsilyl, and R8 and R9 may be terminal carboxyl groups which are independently a C1-C6 linear alkyl group which is preferably methyl).

[0020] In equation (I), R1 and R2 are, independently, hydrogen, C1~C 12 Linear or branched alkyl, C2-C 12 Linear or branched alkenyl, C1-C 12 Linear or branched alkoxy, C3-C 12 Cycloalkyl, C2~C 12 Cycloalkoxy, C6~C 12 Aryl, C6~C 12 Aryloxy, C7~C 14 Arylalkyl, C7~C 14 Alkylaryl, C6~C 24 Alkylaryloxy, C5~C 24Aralkil, or C6~C 24 It may also be an aralkoxy group. Preferably, R1 and R2 are each independently a C1-C6 linear or branched alkyl, a C2-C6 linear or branched alkenyl, a C1-C6 linear or branched alkoxy, or a C3-C 12 Cycloalkyl, C2~C 12 Cycloalkoxy, or C6-C 12 It may also be an aryl group. Preferably, R1 and R2 are each independently a C1-C6 linear or branched alkyl, a C2-C6 linear or branched alkenyl, a C1-C6 linear or branched alkoxy, or a C6-C 12 They may be aryl groups. Preferably, R1 and R2 may each be independently a C1-C3 linear or branched alkyl group, a C2-C3 linear or branched alkenyl group, a C1-C3 linear or branched alkoxy group, or a C6 aryl group. For example, R1 and R2 may each be independently a methyl, tert-butyl, propa-1-enyl, ethoxy, or phenyl group. More preferably, R1 and R2 are methyl groups.

[0021] R3 and R4 are independently hydrogen, C1~C 12 Linear or branched alkyl groups, C3-C 12 Cycloalkyl, C6~C 12 Aryl, C5~C 24 Aralkil, or C5~C 24 It may also be an alkali group. Preferably, R3 and R4 are each independently a C1-C6 linear or branched alkyl, a C2-C6 linear or branched alkenyl, a C1-C6 linear or branched alkoxy, or a C6-C 12 They may be aryl groups. More preferably, R3 and R4 may each be independently a hydrogen or a methyl group. In certain embodiments, R3 / R4 and "A" together form a C6 aryl group.

[0022] "A" may independently be a substituted or unsubstituted C1-C6 linear alkyl group, one or more heteroatoms selected from the group consisting of O, NR7, S, and SiR8R9, or a substituted or unsubstituted C1-C6 linear alkyl group containing one or more heteroatoms selected from the group consisting of O, NR7, S, and SiR8R9. Preferably, "A" may independently be a substituted or unsubstituted C1-C3 linear alkyl group, one or more heteroatoms selected from the group consisting of O, NR7, S, and SiR8R9, or a substituted or unsubstituted C1-C3 linear alkyl group containing one or more heteroatoms selected from the group consisting of O, NR7, S, and SiR8R9. When "A" is substituted, it may be a C1-C6 linear alkyl group and a C6-C 12 It may be substituted with one or more groups selected from the group consisting of aryl groups. Preferably, "A" may be substituted with a C1-C3 linear alkyl group or a C6 aryl group. More preferably, "A" may be substituted with a C1 group. R7 may be hydrogen, a C1-C6 linear alkyl group, such as methyl, or trimethylsilyl. R8 and R9 may independently be a C1-C6 linear alkyl group, such as methyl.

[0023] Preferably, A is a C2 alkyl group containing a sulfur atom. The structure of "A" as a C2 alkyl group containing a sulfur atom is shown below.

[0024] [ka]

[0025] The carboxyl group is represented by formula (II):

[0026] [ka] (In the ceremony R1 and R2 are as defined above for equation (I), R3 and R4 are as defined above for equation (I), A is defined above for equation (I), M is a metal or metalloid with a valency of 1 to 4, such as Li, Na, K, Mg, Ca, Zn, Fe, Co, Ni, Al, Nd, Ti, Sn, Si, Zr, V, Mo, or W. n can exist as a carboxylate (where n is an integer between 1 and 4).

[0027] In the compound of formula (II), M may be Li, and n may be 1.

[0028] The further definitions of R1, R2, R3, R4, R7, R8, and R9 in equation (II) are the same as those defined above for equation (I).

[0029] Functionalized SBR can be obtained by reacting an SSBR copolymer with one or more functionalizing reagents in the form of a silalactone. Silaractone is given by formula (III):

[0030] [ka] (In the formula, R1 and R2 are as defined above for equation (I), R3 and R4 are as defined above for equation (I), A may be a compound of formula (I) as defined above.

[0031] Further definitions of R1, R2, R3, R4, R7, R8, and R9 in equation (III) are as described above for equation (I).

[0032] Advantageously, the silalactone of formula (III) is 2,2-dimethyl-1-oxa-2-silacyclohexane-6-one, 2,2,4-trimethyl-1-oxa-2-silacyclohexane-6-one, 2,2,5-trimethyl-1-oxa-2-silacyclohexane-6-one, 2,2,4,5-tetramethyl-1-oxa-2-silacyclohexane-6-one, 2,2-diethyl-1-oxa-2-silacyclohexane-8-one, 2,2-diethoxy-1-oxa-2-silacyclohexane-6-one, 2,2-dimethyl- 1,4-Dioxa-2-Silacyclohexane-6-one, 2,2,5-Trimethyl-1,4-Dioxa-2-Silacyclohexane-6-one, 2,2,3,3-Tetramethyl-1,4-Dioxa-2-Silacyclohexane-6-one, 2,2-Dimethyl-1-Oxa-4-Thi-2-Silacyclohexane-6-one, 2,2-Diethyl-1-Oxa-4-Thi-2-Silacyclohexane-6-one, 2,2-Diphenyl-1-Oxa-4-Thi-2-Silacyclohexane-6-one, 2-Methyl-2-Ethenyl-1-Ox S-4-thia-2-silacyclohexane-6-one, 2,2,5-trimethyl-1-oxa-4-thia-2-silacyclohexane-6-one, 2,2-dimethyl-1-oxa-4-aza-2-silacyclohexane-6-one, 2,2,4-trimethyl-1-oxa-4-aza-2-silacyclohexane-6-one, 2,4-dimethyl-2-phenyl-1-oxa-4-aza-2-silacyclohexane-6-one, 2,2-dimethyl-4-trimethylsilyl-1-oxa-4-aza-2-silacyclohexane-8-one, 2 ,2-diethoxy-4-methyl-1-oxa-4-aza-2-silacyclohexane-6-one, 2,2,4,4-tetramethyl-1-oxa-2,4-disilacyclohexane-8-one, 3,4-dihydro-3,3-dimethyl-1H-2,3-benzoxacillin-1-one, 2,2-dimethyl-1-oxa-2-silacyclopentan-5-one, 2,2,3-trimethyl-1-oxa-2-silacyclopenten-5-one, 2,2-dimethyl-4-phenyl-1-oxa-2-silacyclopentan-5-one, 2,2,It may be one or more selected from the group consisting of 4-(tert-butyl)-1-oxa-2-silacyclopentan-5-one, 2-methyl-2-(2-propen-1-yl)-1-oxa-2-silacyclopentan-5-one, 1,1-dimethyl-2,1-benzoxasilol-3(1H)-one, and 2,2-dimethyl-1-oxa-2-silacycloheptan-7-one. Preferably, the silalactone of formula (III) is 2,2-dimethyl-1-oxa-4-thia-2-silacyclohexane-6-one. The structure of 2,2-dimethyl-1-oxa-4-thia-2-silacyclohexane-6-one is shown below.

[0033] [ka]

[0034] The carboxyl group is represented by formula (V):

[0035] [ka] (In the formula, n is an integer between 3 and 6. R5 and R6 are the same or different, and each is independently a hydrogen, alkyl, cycloalkyl, aryl, alkalil, or aralkyl group. They may contain one or more heteroatoms, preferably one or more heteroatoms selected from the group consisting of O, N, S, or Si, and can be bonded to the SBR copolymer via one or more divalent structural elements.

[0036] When divalent structural elements are present, the SBR copolymer is bonded at the silicon ends of the divalent structural elements according to the following:

[0037] [ka]

[0038] The silane-containing carboxyl group of formula (I) or (II) is bonded to the oxygen terminus of the divalent structural element of formula (V) if a divalent structural element is present.

[0039] The divalent structural element of equation (V) is given by equation (IV):

[0040] [ka] (In the formula, n is as defined above for equation (V), R5 and R6 can be derived from cyclosiloxanes such as the cyclosiloxane of formula (V) as defined above.

[0041] R5 and R6 are independently composed of hydrogen, C1-C 12 Linear or branched alkyl groups, C3-C 12 Cycloalkyl, C6~C 12 Aryl, C7~C 14 Aralkil, or C7~C 14 It may also be an alkali group. Preferably, R5 and R6 may each be independently a C1-C6 linear or branched alkyl group, preferably a C1-C3 linear alkyl group, and more preferably a methyl group.

[0042] The divalent structural element of formula (V) can be derived from one or more selected from the group consisting of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane. Preferably, the divalent structural element is derived from hexamethylcyclotrisiloxane.

[0043] It is particularly advantageous that the SBR copolymer is terminated with carboxyl groups derived from 2,2-dimethyl-1-oxa-4-thia-2-silacyclohexane-6-one, which are bonded to the polymer via divalent structural elements derived from hexamethylcyclotrisiloxane. In this embodiment, the carboxyl groups of formula (I) (having R1, R2, R3 and R4 as methyl groups and "A" as the above-mentioned S atom-containing C2 alkyl group) are bonded to the copolymer by divalent structural elements of formula (V), where R5 and R6 are methyl groups and n is 3.

[0044] In embodiments in which SBR is functionalized with aminosilane groups, these groups are preferably of formula (VI):

[0045] [ka] (In the ceremony A is C1~C 12 Alkylene group or C1~C 12 It is an alkenylene group, R 10 and R 11 These are, independently, C1~C 12 Alkyl alkyl groups, C1-C 12 Alkenyl group, and C1-C 12 Selected from alkoxy groups, R 12 , R 13 and R 14 These are, independently, C1~C 12 Alkyl alkyl groups, C1-C 12 Alkenyl group, and C1-C 12 Selected from alkoxy groups, R 15 C1~C 12 Alkyl or -SiR 16 R 17 R 18 It may be a base, R 16 , R 17 and R 18 These are, independently, C1~C 12 Alkyl alkyl groups, C1-C 12 Alkenyl group, and C1-C12 It is a terminal amino silane group having a structure (selected from alkoxy groups).

[0046] Preferably, A is a C1 - C 12 alkylene group, R 10 and R 11 are each independently selected from C1 - C 12 alkyl groups and C1 - C 12 alkoxy groups, R 12 、R 13 and R 14 are each independently selected from C1 - C 12 alkyl groups, C1 - C 12 alkenyl groups, and C1 - C 12 alkoxy groups, R 15 is a -SiR 16 R 17 R 18 group, where R 16 、R 17 and R 18 are each independently selected from C1 - C 12 alkyl groups, C1 - C 12 alkenyl groups, and C1 - C 12 alkoxy groups.

[0047] More preferably, A is a C2 - C4 alkylene group, R 10 is a C1 - C4 alkoxy group, R 11 is a C1 - C4 alkyl group, R 12 、R 13 and R 14 are each independently C1 - C4 alkyl groups, R 15 is a -SiR 16 R 17 R 18 group, and R 16 、R 17 and R 18 are each independently C1 - C4 alkyl groups.

[0048] More preferably, A is a C2-C4 alkylene group, R 10 is a C1-C4 alkoxy group, R 11 is a C1-C4 alkyl group, R 12 、R 13 and R 14 are C1-C3 alkyl groups, R 15 is a -SiR 16 R 17 R 18 group, and R 16 、R 17 and R 18 are C1-C3 alkyl groups.

[0049] The composition may further contain a diene elastomer. The diene elastomer is an elastomer derived from a diene monomer, i.e., a monomer having two carbon-carbon double bonds which may or may not be conjugated, at least partially (e.g., in a homopolymer or copolymer). Examples of suitable diene elastomers include polybutadiene, natural rubber, synthetic polyisoprene, butadiene copolymers, isoprene copolymers and mixtures thereof. In a preferred embodiment, the diene elastomer is polybutadiene rubber. When present, the diene elastomer may be present in an amount of up to 50 phr, preferably up to 40 phr.

[0050] Oil The rubber composition is at standard ambient temperature and pressure (25 °C, 10 5It contains one or more oils that are liquid at Pa). These are sometimes also called liquid plasticizers. The oils may have a glass transition temperature of less than -20°C. These oils may be one or more selected from the group consisting of, for example, liquid diene polymers, polyolefin oils, naphthenic oils, paraffin oils, DAE oils, MES (medium extract solvate) oils, TDAE (treated distillate aromatic extract) oils, RAE oils (residual aromatic extract oils), TRAE oils (treated residual aromatic extracts), and SRAE oils (safe residual aromatic extract oils), mineral oils, vegetable oils, ether plasticizers, ester plasticizers, preferably RAE oils, oleates, such as octyl oleate or 2-ethylhexyl oleate, phosphate plasticizers, sulfonic acid plasticizers, and mixtures thereof. More preferably, the oil is a mixture of octyl oleate and RAE oil. The oil may be present in amounts of 10-40 phr, preferably 20-35 phr, more preferably 25-30 phr, for example, 25, 26, 27, 28, 29, or 30 phr.

[0051] hydrocarbon resins The resin is produced at standard ambient temperature and pressure (25°C, 10°C). 5 Hydrocarbon resins are solid or highly viscous compounds at Pa. Hydrocarbon resins are essentially carbon and hydrogen-based, but may also contain other types of atoms. They can be aliphatic, alicyclic, aromatic, hydrogenated aromatic, and aliphatic / aromatic, i.e., based on aliphatic and / or aromatic monomers. Hydrocarbon resins may also qualify as thermoplastic resins in the sense that they soften when heated and are therefore moldable.

[0052] Examples of such hydrocarbon resins include cyclopentadiene homopolymer or copolymer resins (abbreviated as CPD), dicyclopentadiene homopolymer or copolymer resins (abbreviated as DCPD), terpene homopolymer or copolymer resins, rosinic resins, C5 homopolymer or copolymer resins which may be partially or completely hydrogenated, C9 homopolymer or copolymer resins which may be partially or completely hydrogenated, alpha-methylstyrene homopolymer or copolymer resins, and combinations thereof, selected from the group. Any hydrocarbon resin containing heteroatom functional groups and satisfying the glass transition temperature requirements may be used in the present invention.

[0053] The hydrocarbon resin containing heteroatom functional groups may be present in amounts of 5 to 50 phr, preferably 10 to 40 phr, preferably 15 to 35 phr, more preferably 25 to 30 phr, for example, 25, 26, 27, 28, 29, or 30 phr.

[0054] A hydrocarbon resin containing a heteroatom functional group may be a hydrocarbon resin containing a heteroatom functional group selected from the group consisting of alcohols, carboxyls, esters, amides, amines, thiols, and sulfonic acids. Preferably, the heteroatom functional group is a carboxyl group. Therefore, a hydrocarbon resin containing a heteroatom functional group may also be a hydrocarbon resin containing a carboxyl group.

[0055] In a particularly preferred embodiment, the hydrocarbon resin containing a carboxyl group is a rosin resin. Rosin resins include resins (e.g., resin acids or rosin acids) which are mixtures of isomerized organic acids characterized by a common structure containing three C6 condensed rings, a double bond, and a single carboxyl group. Rosin is a solid resin material naturally present in pine trees. There are three main sources of rosin: (1) gum rosin derived from oil-containing resin extruded from green pine trees, (2) wood rosin derived from oil-containing resin contained in old stumps, and (3) tall oil rosin derived from waste carboxyl groups in liquid recovered as a by-product of the kraft paper industry. The main component of rosin is typically abietic acid. Rosin resins include rosin ester resins, which may be esters of rosin with polyhydric alcohols. The polyhydric alcohol can be selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylene glycol, pentaerythritol, dipentaerythritol, tripentaerythritol, trimethylolethane, trimethylolpropane, mannitol, sorbitol, and mixtures thereof. Any rosin resin that satisfies the glass transition temperature requirement can be suitably used in the present invention. A suitable rosin resin is Kraton Sylvatraxx 2097.

[0056] The softening point of rosin resins is above 50°C, preferably 70°C to 130°C, more preferably 90°C to 110°C, for example, 90°C, 95°C, 100°C, or 110°C, or any intermediate value. The softening point of a material is the temperature at which it softens beyond a certain degree and is measured using a ring and ball apparatus in accordance with ISO 4625.

[0057] 1 The aromaticity of rosin-based resins, as measured by 1H NMR, may be greater than 1, preferably 3.5 to 9.5, and preferably 6.5. The aromaticity values ​​defined herein are: 1It is measured by 1H NMR as the content of aromatic protons with a chemical shift of 6.5–8.5 ppm.

[0058] The total amount of hydrocarbon resin containing heteroatom functional groups and oil may be 45 to 70 phr, preferably 50 to 60 phr, for example 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or 60 phr.

[0059] The ratio of hydrocarbon resin containing heteroatom functional groups to oil may be 3:1 to 1:3, preferably 2:1 to 1:2, and more preferably 1.5:1 to 1:1.5.

[0060] Filler components The rubber composition may further include an inorganic reinforcing filler which may include a silica-based mineral filler and / or an aluminum-based mineral filler. The inventors have found that high surface area silica may be beneficial in providing the technical effects of the present invention. Preferably, the high surface area silica has at least 150 m 2 g -1 Preferably 175-225m 2 g -1 More preferably 185-215m 2 g -1 For example, 185, 190, 195, 200, 205, 210 or 215m 2 g -1 It has a CTAB specific surface area.

[0061] Suitable additional silaceous fillers include precipitated amorphous silica, wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), fumed silica, calcium silicate, aluminum silicate, magnesium silicate (e.g., Mg2SiO4, MgSiO3), calcium magnesium silicate (CaMgSiO4), and calcium aluminum silicate (e.g., Al2O3·CaO2SiO2). Preferably, the aluminum-based filler is alumina (Al2O3) or aluminum hydroxide (e.g., Al(OH)3). In a preferred embodiment, the inorganic reinforcing filler is a combination of silica and aluminum hydroxide (Al(OH)3). The total amount of the inorganic reinforcing filler (e.g., silica) may be at least 70 phr, preferably 120 to 140 phr.

[0062] The rubber composition may contain additional fillers such as carbon black (i.e., fillers in addition to inorganic reinforcing fillers). The carbon black may be furnace black, channel black, and lamp black. For example, the carbon black may be one or more selected from the group consisting of super abrasion-resistant furnace (SAF) black, high abrasion-resistant furnace (HAF) black, good extrudeable furnace (FEF) black, fine furnace (FF) black, semi-super abrasion-resistant furnace (ISAF) black, medium-reinforced furnace (SRF) black, medium processable channel black, difficult-to-process channel black, and conductive channel black. Other carbon blacks that may be used include acetylene black. The carbon black may be in pelletized form or in unpelleted cotton-like masses. A specific example of the carbon black in the rubber composition of the present invention is CORAX® N234 by Orion Engineered Carbons. The amount of carbon black contained in the rubber composition of the present invention is not particularly limited, but may be 0.1 to 20 parts by weight of the rubber component, for example, 5 to 15 phr, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 phr.

[0063] Additional ingredients The rubber composition is suitable for use at standard ambient temperature and pressure (25°C, 10°C). 5 The mixture may further contain one or more oils that are liquid at Pa. These are sometimes also called liquid plasticizers. These oils may be, for example, one or more selected from the group consisting of liquid diene polymers, polyolefin oils, naphthenic oils, paraffin oils, DAE oils, MES (medium extract solvate) oils, TDAE (treated distillate aromatic extract) oils, RAE oils (residual aromatic extract oils), TRAE oils (treated residual aromatic extracts), and SRAE oils (safe residual aromatic extract oils), mineral oils, vegetable oils, ether plasticizers, ester plasticizers, preferably oleates, such as octyl oleate or 2-ethylhexyl oleate, phosphate plasticizers, sulfonic acid plasticizers, and mixtures thereof. In a preferred embodiment, the oil may be a combination of TDAE oil and octyl oleate. The oil may be present in an amount of at least 1 phr, preferably 5 to 40 phr, more preferably 7 to 15 phr, for example, 7, 8, 9, 10, 11, 12, 13, 14, or 15 phr.

[0064] In addition to the components described above, the rubber composition may include additional components that are useful to those skilled in the art for preparing a rubber composition suitable for the preparation of pneumatic tires. These include, for example, vulcanizing agents (e.g., sulfur), vulcanization accelerators, vulcanization accelerators, silane coupling agents, degradation inhibitors (e.g., antioxidants or ozone degradation inhibitors), waxes, and processing agents.

[0065] In a preferred embodiment, SBR containing heteroatomic functional groups is present in amounts of 60-100 phr, and T is present at -65°C to -55°C. g It has formula (I):

[0066] [ka] (In the ceremony R1 and R2 are the same or different, and each is independently a hydrogen, alkyl, alkoxy, cycloalkyl, cycloalkoxy, aryl, aryloxy, alkylaryl, alkylaryloxy, aralkyl, or aralkoxy group, which may contain one or more heteroatoms, preferably one or more heteroatoms selected from the group consisting of O, N, S, and Si. R3 and R4 are the same or different, and each is independently a hydrogen, alkyl, cycloalkyl, aryl, alkaryl, or aralkyl group, which may contain one or more heteroatoms, preferably one or more heteroatoms selected from the group consisting of O, N, S, and Si. A is a divalent organic group which may be an alkyl group; one or more heteroatoms selected from the group consisting of O, NR7, S, and SiR8R9; or an alkyl group which contains one or more heteroatoms, preferably one or more heteroatoms selected from the group consisting of O, NR7, S, and SiR8R9, where R7 may be hydrogen, a C1-C6 linear alkyl group which is preferably methyl, or trimethylsilyl, and R8 and R9 may independently be a C1-C6 linear alkyl group which is preferably methyl) and comprises a terminal aminosilane group having a structure. Hydrocarbon resins containing heteroatom functional groups are suitable for temperatures below 60°C. g It is a rosin-based resin that has the following properties, and is present in an amount of 25-30 phr. The oil is a mixture of RAE oil and 2-ethylhexyl oleate, and the oil is present in an amount of 25-30 phr. The total concentration of hydrocarbon resins and oils containing heteroatom functional groups is 50-60 phr.

[0067] In another preferred embodiment, SBR containing heteroatomic functional groups is present in amounts of 60-100 phr, and T is present at -65°C to -55°C. g It has formula (VI):

[0068] [ka] (In the ceremony A is a C2-C4 alkylene group, R 10 R is a C1-C4 alkoxy group, 11 These are C1-C4 alkyl groups, R 12 , R 13 and R 14 These are C1-C3 alkyl groups, R 15 -SiR 16 R 17 R 18 It is a base, R 16 , R 17 and R 18 It contains a terminal aminosilane group having a structure (which is a C1-C3 alkyl group), Hydrocarbon resins containing heteroatom functional groups are suitable for temperatures below 60°C. g It is a rosin-based resin that has the following properties, and is present in an amount of 25-30 phr. The oil is a mixture of RAE oil and 2-ethylhexyl oleate, and the oil is present in an amount of 25-30 phr. The total concentration of hydrocarbon resins containing heteroatom functional groups and oils is 50-60 phr.

[0069] When preparing the rubber composition of the present invention, the method for combining each component is not limited, and any method well known to those skilled in the art may be used. For example, all component materials may be compounded and kneaded at once, or they may be compounded and kneaded in multiple steps. For compounding and kneading, a kneader such as a roll kneader, an internal mixer, or a Banbury mixer may be used. Any well known molding machine such as an extruder or a press molding machine may be used to form the rubber composition into a sheet or strip. The vulcanization conditions for curing the rubber composition are not limited, and any conditions well known to those skilled in the art may be used. However, typically, vulcanization conditions of 140 to 180°C for 5 to 120 minutes are used.

[0070] Unless otherwise specified, the amounts of components in the rubber composition of the present invention are given in parts per 100 parts (phr), which means parts by weight per 100 parts of elastomer (or, if several elastomers are present, the total elastomer). The term "rubber composition" may be used interchangeably with the term "rubber compound."

[0071] pneumatic tires In a further embodiment, the present invention relates to a pneumatic tire. The pneumatic tire is not particularly limited and may be any tire used on passenger vehicles such as cars, motorcycles, and commercial vehicles. The pneumatic tire may be suitable for any type of climate, weather, or road conditions and may be, for example, a summer tire, a winter tire, a snow tire, an all-season tire, or a high-performance tire.

[0072] Taking the above into consideration, the present invention relates to a pneumatic tire comprising the rubber composition of the present invention and / or a pneumatic tire prepared from the rubber composition of the present invention.

[0073] In a further embodiment, the present invention relates to the use of rubber compositions in the manufacture of pneumatic tires.

[0074] There are no particular restrictions on which part of the tire the rubber composition of the present invention can be used in, and it can be appropriately selected according to the intended purpose. For example, the rubber composition of the present invention can be used in the tread, base tread, sidewall, side reinforcement rubber, bead filler, etc. In particular, the rubber composition of the present invention can be advantageously used in the tread component.

[0075] Regarding the manufacturing method of the tire, any method well known to those skilled in the art can be used. For example, a green tire can be obtained by sequentially stacking components commonly used in tire manufacturing, such as a carcass layer, belt layer, and tread layer, formed from at least one selected from the group consisting of unvulcanized rubber compositions and cords, on a tire molding drum, and then removing the drum. Then, the desired tire can be manufactured by vulcanizing this green tire under heat according to a conventional method. [Examples]

[0076] The present invention will be described by the following non-limiting embodiments.

[0077] Measurement method Glass transition temperature (T g ) glass transition temperature Tg The values ​​were measured using DSC (Differential Scanning Calorimetry) in accordance with the ASTM D3418 standard (1999).

[0078] Cetyltrimethylammonium bromide (CTAB) adsorption method - Measurement was performed by the CTAB method in accordance with ISO 5794-1G.

[0079] Loss factor (tanδ) Rolling resistance and wet traction are evaluated using loss coefficients (tangent δ, or tanδ) at different temperatures. tanδ at 0°C is a predictor of wet grip. tanδ at 60°C is a predictor of rolling resistance (RR). Polymer admixture is indicated by the ratio of tanδ at 0°C to tanδ at 60°C. Dynamic physical tests to determine tanδ were performed in accordance with ISO 4664.

[0080] Modulus of elasticity (E') The modulus of elasticity (E') is used to evaluate grip performance. Dynamic physical tests to determine E' at 30°C and -20°C were performed in accordance with ISO 4664 standards. E' at 30°C is used as an indicator of dry balance / handling. The ratio of E' at 30°C to tanδ at 60°C is a predictor of dry grip.

[0081] Mooney viscosity Mooney viscosity was measured for raw polymers in accordance with ASTM D 1646 standard.

[0082] Processability Processability or compound viscosity is measured using a rubber process analyzer by measuring the shear modulus (G') of the rubber compound at 130°C and 100% strain before vulcanization.

[0083] General method The following components were blended in the amounts listed in Table 1 below. In Table 1, all amounts are parts per 100 parts (phr) of rubber. When preparing the rubber composition of the present invention, the method for combining each component is not limited, and any method well known to those skilled in the art may be used. For example, all component materials may be blended and kneaded at once, or they may be blended and kneaded in multiple steps. Mixing machines such as roll mixers, internal mixers, or Banbury mixers may be used for blending and kneading. Any well known molding machine such as an extruder or press molding machine may be used to form the rubber composition into a sheet or strip.

[0084] component Elastomer: A functionalized solution of styrene-butadiene rubber (ENEOS HPR540) (SSBR1) functionalized with terminal aminosilane groups of formula (VI). Functionalized with terminal carboxyl groups, at -60°C T g A functionalized solution of styrene-butadiene rubber having an average MW of 690 kDa (prepared using the method described in International Publication No. 2014 / 173706(A1)) (SSBR2) Silica: CTAB surface area 185-215 m² 2 g -1 and NSA surface area 215~255m 2 g -1 High surface area silica (Evonik ULTRASIL® 9100GR) Hydrocarbon resins: 69~79℃ T g C5 resin (Eastman IMPERA E1780) containing 49℃ T g Rosin-based resin having (Kraton Silvatraxx 2097) Oil: Octyl oleate RAE oil (Repsol Extensoil 14) Further additives: Carbon Black (Corax® N234) Silane (Evonik Industries AG Si 69 (registered trademark)) Aluminum trihydroxylate (Al(OH)3) Zinc stearate sulfur 1,3-Diphenylguanidine (DPG) Zinc oxide (ZnO) Stearic acid 2,2,4-Trimethyl-1,2-Dihydroquinoline Polymer (TMQ) Paraffin wax Dibenzothiadyl disulfide (MBTS) N-cyclohexyl-2-benzothiadylsulfenamide (CBS) N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) Early vulcanization inhibitor (PVI)

[0085] [Table 1]

[0086] Table 2 shows the results of various mechanical property measurements performed on tread pieces prepared using the compositions in Table 1.

[0087] [Table 2]

[0088] The resin is low T g It is known that polymers have low miscibility, resulting in low dispersibility of fillers and high rigidity. The inventors have discovered that by combining a polymer containing heteroatom functional groups with a resin containing heteroatom functional groups, the miscibility of the resin in the matrix can be increased. This miscibility increases hysteresis loss in the 0-30°C range, which controls wet / dry grip. For this purpose, an improvement in the balance of wet / dry grip / dry handling was obtained while maintaining winter performance without affecting processability. In particular, by combining a polymer functionalized with carboxyl groups, the miscibility between the resin and polymer can be increased. This results in higher polymer / resin miscibility, improving the balance of wet / dry grip / dry handling while maintaining winter performance without affecting processability.

Claims

1. Glass transition temperature (T) between -90°C and -30°C ｇ A copolymer (SBR) of styrene and butadiene having ) and containing a heteroatom functional group, Optionally, diene elastomer and T ｇ A hydrocarbon resin containing a heteroatom functional group having, Contains oil, A rubber composition for pneumatic tires, wherein the total amount of the hydrocarbon resin and the oil is at least 40 phr.

2. The aforementioned SBR is T ｇ The rubber composition according to claim 1, having the following characteristics.

3. The rubber composition according to claim 1 or 2, wherein the SBR is present in an amount of at least 50 phr, preferably 60 to 100 phr, and more preferably 100 phr.

4. The rubber composition according to any one of claims 1 to 3, wherein the SBR containing a heteroatom functional group is a heteroatom functional group selected from the group consisting of alcohol, carboxyl, ester, amide, amine, imine, imide, nitrile, oxime, thiol, sulfide, sulfoxide, sulfone, sulfinic acid, sulfonic acid, sulfonic acid ester, thiocarboxylic acid, thioester, silane, alkoxysilane, aminosilane, and silanol, and combinations thereof, preferably containing a carboxyl or aminosilane.

5. The rubber composition according to any one of claims 1 to 4, wherein the SBR is functionalized with carboxyl groups, preferably terminal carboxyl groups.

6. The terminal carboxyl group is of formula (I): 【Chemistry 1】 (In the ceremony R １ and R ２ These are the same or different groups, each independently of the other, and are hydrogen, alkyl, alkoxy, cycloalkyl, cycloalkoxy, aryl, aryloxy, alkylaryl, alkylaryloxy, aralkyl, or aralkoxy groups, which may contain one or more heteroatoms, preferably one or more heteroatoms selected from the group consisting of O, N, S, and Si. R ３ and R ４ These are the same or different groups, each independently of a hydrogen, alkyl, cycloalkyl, aryl, alkaryl, or aralkyl group, which may contain one or more heteroatoms, preferably one or more heteroatoms selected from the group consisting of O, N, S, and Si. A is a divalent organic group which may be an alkyl group; O, NR ７ , S and SiR ８ R ９ selected from the group consisting of one or more heteroatoms; or an alkyl group containing one or more heteroatoms, preferably, the heteroatom is O, NR ７ , S, and SiR ８ R ９ selected from the group consisting of one or more, R ７ is hydrogen, C １ to C ６ linear alkyl or trimethylsilyl may be, R ８ and R ９ are independently C １ to C ６ linear alkyl may be) a group, the rubber composition according to claim 5.

7. The terminal carboxyl group is of formula (V): 【Chemistry 2】 The SBR is bonded via one or more divalent structural elements, preferably the divalent structural elements are of formula (IV): 【Transformation 3】 (In the formula, n is an integer between 3 and 6. R ５ , R ６ The rubber composition according to claim 5 or 6, wherein each is the same or different, independently of a hydrogen, alkyl, cycloalkyl, aryl, alkaryl, or aralkyl group, which may contain one or more heteroatoms, preferably the heteroatom being O, N, S, or Si, and more preferably the divalent structural element is derived from a cyclosiloxane (derived from one or more cyclosiloxanes selected from the group consisting of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane).

8. The terminal aminosilane functional group is of formula (VI) 【Chemistry 4】 (In the ceremony A is C １ ~C １２ Alkylene group or C １ ~C １２ It is an alkenylene group, R １０ and R １１ Independently, C １ ~C １２ alkyl group, C １ ~C １２ Alkenyl group and C １ ~C １２ Selected from alkoxy groups, R １２ , R １３ , and R １４ Independently, C １ ~C １２ alkyl group, C １ ~C １２ Alkenyl group and C １ ~C １２ Selected from alkoxy groups, R １５ C １ ~C １２ Alkyl alkyl group or -SiR １６ R １７ R １８ It may also be a base, R １６ , R １７ and R １８ Independently, C １ ~C １２ alkyl group, C １ ~C １２ Alkenyl group and C １ ~C １２ A rubber composition according to any one of claims 1 to 4, having a structure (selected from alkoxy groups).

9. A is C １ ~C １２ It is an alkylene group, R １０ and R １１ However, independently, C １ ~C １２ Alkyl and C １ ~C １２ Selected from alkoxy groups, R １２ , R １３ , and R １４ However, independently, C １ ~C １２ alkyl group, C １ ~C １２ Alkenyl group and C １ ~C １２ Selected from alkoxy groups, R １５ However, -SiR １６ R １７ R １８ It is a base, R １６ , R １７ and R １８ Independently, C １ ~C １２ alkyl group, C １ ~C １２ Alkenyl group and C １ ~C １２ The rubber composition according to claim 8, wherein the alkoxy group is selected from the alkoxy group.

10. A is C ２ ~C ４ an alkylene group, R １０ However, C １ ~C ４ It is an alkoxy group, R １１ However, C １ ~C ４ It is an alkyl group, R １２ 、 R １３ and R １４ are each independently a C １ -C ４ alkyl group, R １５ However, -SiR １６ R １７ R １８ It is a base, R １６ , R １７ and R １８ Each of them is independent of C １ ~C ４ The rubber composition according to claim 8 or 9, wherein the alkyl group is an alkyl group.

11. A is C ２ ~C ４ It is an alkylene group, R １０ However, C １ ~C ４ It is an alkoxy group, R １１ However, C １ ~C ４ It is an alkyl group, R １２ , R １３ and R １４ However, C １ ~C ３ It is an alkyl group, R １５ However, -SiR １６ R １７ R １８ It is a base, R １６ , R １７ and R １８ C １ ~C ３ The rubber composition according to any one of claims 8 to 10, wherein the alkyl group is an alkyl group.

12. The rubber composition according to any one of claims 1 to 11, wherein the oil is one or more selected from the group consisting of liquid diene polymer, polyolefin oil, naphthenic oil, paraffin oil, DAE oil, MES (medium extraction solvate) oil, TDAE (treated distillate aromatic extract) oil, RAE oil (residual aromatic extract oil), TRAE oil (treated residual aromatic extract), and SRAE oil (safe residual aromatic extract oil), mineral oil, vegetable oil, ether plasticizer, ester plasticizer, oleate, for example, octyl oleate or 2-ethylhexyl oleate, phosphate plasticizer, sulfonic acid plasticizer, and mixtures thereof.

13. The rubber composition according to any one of claims 1 to 12, wherein the hydrocarbon resin containing the heteroatom functional group is a hydrocarbon resin containing a heteroatom functional group selected from the group consisting of alcohol, carboxyl, ester, amide, amine, thiol, and sulfonic acid, preferably a carboxyl group.

14. The rubber composition according to any one of claims 1 to 13, wherein the hydrocarbon resin containing the heteroatom functional group is a hydrocarbon resin containing a carboxyl group.

15. The rubber composition according to claim 14, wherein the hydrocarbon resin having a carboxyl group is a rosin-based resin.

16. The rubber composition according to any one of claims 1 to 15, wherein the hydrocarbon resin is present in an amount of 5 to 50 phr, preferably 10 to 40 phr, preferably 15 to 35 phr, and more preferably 25 to 30 phr.

17. The rubber composition according to any one of claims 1 to 16, wherein the oil comprises RAE oil and octyl oleate.

18. The rubber composition according to any one of claims 1 to 17, wherein the oil is present in an amount of 10 to 40 phr, preferably 20 to 35 phr, and more preferably 25 to 30 phr.

19. The rubber composition according to any one of claims 1 to 18, wherein the total amount of the hydrocarbon resin and the oil is 45 to 70 phr, preferably 50 to 60 phr.

20. The rubber composition according to any one of claims 1 to 19, wherein the ratio of the hydrocarbon resin to the oil is 3:1 to 1:3, preferably 2:1 to 1:2, and more preferably 1.5:1 to 1:1.

5.

21. A pneumatic tire comprising the rubber composition according to any one of claims 1 to 20.

22. A pneumatic tire prepared from the rubber composition according to any one of claims 1 to 20.

23. Use of the rubber composition according to any one of claims 1 to 20 in the manufacture of a pneumatic tire.

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