Rubber composition containing bioelastic and method for producing same

Abstract

The present invention relates to a rubber composition that is excellent in viscoelastic properties and abrasion resistance, and that can be used for a long period of time by preventing aging over time, and a method for producing the same.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0155903 filed on November 12, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a rubber composition that is excellent in viscoelastic properties and abrasion resistance, and that can be used for a long period of time by preventing aging over time, and a method for producing the same. [Background technology]

[0003] Recently, in response to the need for lower fuel consumption in automobiles, there has been a demand for conjugated diene polymers as rubber materials for tires that have low rolling resistance, excellent abrasion resistance and tensile properties, and also have steering stability, such as wet road resistance.

[0004] In order to reduce the rolling resistance of a tire, there is a method of reducing the hysteresis loss of vulcanized rubber, and as evaluation indexes for such vulcanized rubber, rebound resilience, tan δ, Goodrich heat generation, etc. at 50°C to 80°C are used. In other words, a rubber material that has high rebound resilience or low tan δ and Goodrich heat generation at the above temperatures is preferred.

[0005] Natural rubber, polyisoprene rubber, polybutadiene rubber, etc. are known as rubber materials with low hysteresis loss, but these have the problem of low wet road resistance. For this reason, conjugated diene polymers or copolymers such as styrene-butadiene rubber (hereinafter referred to as SBR) or butadiene rubber (hereinafter referred to as BR) have recently been produced by emulsion polymerization or solution polymerization and used as tire rubber. Among these, the greatest advantage of solution polymerization over emulsion polymerization is that the content of vinyl structure and the content of styrene, which determine the physical properties of rubber, can be freely adjusted, and the molecular weight and physical properties can be adjusted by coupling, modification, etc. Therefore, the structure of the final produced SBR or BR can be easily changed, the movement of the chain ends can be reduced by bonding or modification of the chain ends, and the binding strength with fillers such as silica or carbon black can be increased, and SBR produced by solution polymerization is widely used as a rubber material for tires.

[0006] When such solution-polymerized SBR is used as a rubber material for tires, the glass transition temperature of the rubber can be increased by increasing the vinyl content in the SBR, thereby controlling the tire required physical properties such as running resistance and braking force, and fuel consumption can be reduced by appropriately controlling the glass transition temperature. The solution-polymerized SBR is produced using an anionic polymerization initiator, and the chain ends of the formed polymer are bonded or modified using various modifiers for use. For example, U.S. Patent No. 4,397,994 proposes a technology in which active anions at the chain ends of a polymer obtained by polymerizing styrene-butadiene in a non-polar solvent using an alkyl lithium, which is a monofunctional initiator, are bonded using a bonding agent such as a tin compound.

[0007] Furthermore, in order to improve the processability of solution-polymerized SBR, oil-extended SBR has been developed and is now in use.

[0008] The oil-extended SBR is generally produced by preparing SBR by emulsion polymerization or solution polymerization, adding a petroleum-based oil before removing the solvent, and then removing the solvent, and the petroleum-based oil remaining in the polymer improves the processability of the SBR. When applied to a rubber composition containing the oil-extended SBR, the oil-extended SBR is easily blended with other rubbers and additives, is not easily decomposed during processing, and provides superior properties to the final product, and is used in various fields to obtain many beneficial properties.

[0009] However, petroleum-based oils cause various environmental problems, so there is a need to develop products that have the effective properties of oil-extended SBR and are environmentally friendly, making them applicable to a variety of industries. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] US4397994A [Patent Document 2] KR10-2020-0031529 A Summary of the Invention [Problem to be solved by the invention]

[0011] An object of the present invention is to provide a rubber composition which is excellent in viscoelastic properties and abrasion resistance, and which can be used for a long period of time by preventing aging over time. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention provides a rubber composition and a method for producing the same.

[0013] (1) The present invention provides a rubber composition comprising: (a) a bioelastic containing units derived from a first conjugated diene-based polymer and units derived from a vegetable oil, the first conjugated diene-based polymer having a weight average molecular weight of less than 100,000 g / mol; and (b) a second conjugated diene-based polymer.

[0014] (2) The present invention provides the rubber composition according to (1) above, wherein the first conjugated diene polymer has a weight average molecular weight of 1,000 g / mol to 80,000 g / mol.

[0015] (3) The present invention provides a rubber composition according to (1) or (2) above, wherein the vegetable oil is one or more oils selected from the group consisting of soybean oil, rapeseed oil, canola oil, sunflower oil, linseed oil, rice bran oil, palm oil, olive oil, peanut oil, coconut oil, cottonseed oil, and coconut oil.

[0016] (4) The present invention provides a rubber composition according to any one of the above (1) to (3), wherein the vegetable oil is an epoxidized vegetable oil, and is at least one selected from the group consisting of epoxidized soybean oil, epoxidized rapeseed oil, epoxidized canola oil, epoxidized sunflower oil, epoxidized linseed oil, epoxidized rice bran oil, epoxidized palm oil, epoxidized olive oil, epoxidized peanut oil, epoxidized coconut oil, epoxidized cottonseed oil, and epoxidized coconut oil.

[0017] (5) The present invention provides a rubber composition according to any one of (1) to (4), wherein the second conjugated diene polymer contains a repeating unit derived from a conjugated diene monomer and a repeating unit derived from an aromatic vinyl monomer.

[0018] (6) The present invention provides the rubber composition according to any one of the above (1) to (5), wherein the bioelastic is 5 to 50 parts by weight per 100 parts by weight of the second conjugated diene-based polymer.

[0019] (7) The present invention provides the rubber composition according to any one of the above (1) to (6), further comprising a filler.

[0020] (8) The present invention provides the rubber composition according to the above (7), wherein the filler is at least one selected from the group consisting of silica-based fillers and carbon black-based fillers.

[0021] (9) The present invention provides a method for producing a rubber composition, comprising the steps of: (S1) preparing a bioelastic containing units derived from a first conjugated diene polymer and units derived from a vegetable oil, the first conjugated diene polymer having a weight average molecular weight of less than 100,000 g / mol; (S2) polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in a hydrocarbon solvent in the presence of a polymerization initiator to produce a second conjugated diene polymer; and (S3) mixing the bioelastic with the second conjugated diene polymer.

[0022] (10) The present invention provides a method for producing a rubber composition according to (9), wherein the step (S1) includes a step of polymerizing a conjugated diene monomer to produce an activated polymer having a weight average molecular weight of less than 100,000 g / mol, and a step of reacting the activated polymer with a vegetable oil.

[0023] (11) The present invention provides the method for producing a rubber composition according to (10), wherein the vegetable oil is 0.1 to 50 parts by weight based on 100 parts by weight of the conjugated diene monomer. Effect of the Invention

[0024] The rubber composition according to the present invention has excellent viscoelastic properties and abrasion resistance, and can be used for a long period of time by preventing aging over time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The present invention will now be described in further detail in order to facilitate understanding of the present invention.

[0026] The terms and words used in the description of the present invention and the claims should not be interpreted in a limited manner to their ordinary or dictionary meanings, but should be interpreted in a manner that is consistent with the technical idea of ​​the present invention, based on the principle that the inventors can appropriately define the concepts of terms in order to best describe their invention.

[0027] The present invention will be described in detail below.

[0028] Generally, in order to improve the flexibility, elasticity, compoundability, etc. of synthetic rubber such as conjugated diene polymers, the synthetic rubber is mixed with petroleum-based oil to manufacture the product. However, petroleum-based oil is an environmentally unfriendly material and causes various environmental problems, so there is an increasing need to develop environmentally friendly materials.

[0029] In response to this, a method has been devised in which vegetable oil, an environmentally friendly material derived from plants, is used instead of petroleum-based oil. However, when natural oils such as vegetable oils or low molecular weight liquid rubbers are added during compounding of the rubber composition to improve abrasion resistance, or natural oils are added to rubber after polymerization is completed and a product is manufactured in a stripping process, the abrasion properties are improved, but the low viscosity causes a lot of loss in the equipment used, resulting in a problem of reduced fuel efficiency.

[0030] In addition, it has been pointed out that natural oils have a limitation in that the migration phenomenon causes a clear deterioration in physical properties due to aging when used in products such as tires.

[0031] In order to solve the above problems, the present invention uses a bio-elastic material produced by reacting an anionic conjugated diene polymer with a vegetable oil, instead of the petroleum oil or natural oil that has been conventionally used in the production of rubber compositions. As a result, the rubber composition according to the present invention has excellent viscoelastic properties, abrasion resistance, etc., and has the effect of suppressing aging and improving the stability of physical properties.

[0032] Rubber composition The rubber composition of the present invention includes (a) a bioelastic containing units derived from a first conjugated diene-based polymer and units derived from a vegetable oil, the first conjugated diene-based polymer having a weight average molecular weight of less than 100,000 g / mol, and (b) a second conjugated diene-based polymer.

[0033] (a) Bioelastic In the present invention, the bioelastic comprises units derived from a first conjugated diene based polymer and units derived from a vegetable oil.

[0034] In the present specification, the term "unit derived" may refer to a component or structure derived from a certain substance, or the substance itself. The unit derived from the first conjugated diene polymer may refer to a repeating unit formed during polymerization of a conjugated diene monomer constituting the first conjugated diene polymer, and the unit derived from a vegetable oil may refer to a structure derived from a vegetable oil compound.

[0035] The bioelastic of the present invention may refer to an oil-extended conjugated diene polymer obtained by reacting a renewable organic resource, biomass, i.e., vegetable oil, with a first conjugated diene polymer. For example, it may be a material obtained by reacting vegetable oil, such as triglyceride obtained from a plant, with an activated polymer, i.e., an anionic conjugated diene polymer, produced by living anionic polymerization of a conjugated diene monomer.

[0036] The bioelastic produced by the reaction includes first conjugated diene polymer derived units derived from the first conjugated diene polymer and vegetable oil derived units derived from the vegetable oil.

[0037] The first conjugated diene polymer may be prepared by polymerizing a conjugated diene monomer and may include a unit derived from the conjugated diene monomer. Here, the conjugated diene monomer may be at least one selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene, isoprene, 2-phenyl-1,3-butadiene, and 2-halo-1,3-butadiene (halo means a halogen atom), specifically, 1,3-butadiene, but is not limited thereto.

[0038] In addition, the first conjugated diene polymer may further include a repeating unit derived from an aromatic vinyl monomer, in which case the first conjugated diene polymer may be a copolymer including a repeating unit derived from a conjugated diene monomer and a repeating unit derived from an aromatic vinyl monomer. Here, the repeating unit derived from the aromatic vinyl monomer may refer to a repeating unit formed during polymerization of the aromatic vinyl monomer.

[0039] The aromatic vinyl monomer may be, for example, one or more selected from the group consisting of styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 1-vinylnaphthalene, 4-cyclohexylstyrene, 4-(p-methylphenyl)styrene, 1-vinyl-5-hexylnaphthalene, 3-(2-pyrrolidino ethyl)styrene, 4-(2-pyrrolidino ethyl)styrene, and 3-(2-pyrrolidino-1-methyl ethyl)-methylstyrene, but is not limited thereto.

[0040] The first conjugated diene polymer has a weight average molecular weight of less than 100,000 g / mol. The weight average molecular weight is preferably 1,000 g / mol or more, 5,000 g / mol or more, 10,000 g / mol or more, and 80,000 g / mol or less, 50,000 g / mol or less, or 30,000 g / mol or less, for example, 1,000 g / mol to 80,000 g / mol, or 5,000 g / mol to 50,000 g / mol.

[0041] As described above, by using a conjugated diene-based polymer having a low weight average molecular weight of less than 100,000 g / mol to obtain a bioelastic material, it is possible to obtain a bioelastic material having excellent processability and being used in a variety of applications.

[0042] The bioelastic material is in a form in which units derived from vegetable oil are bonded (coupled) to units derived from a conjugated diene polymer having a low weight average molecular weight within the above range, and has advantages in terms of stability and durability compared to the use of liquid polymers, and can significantly suppress the deterioration of physical properties due to the oil migration phenomenon that occurs in tires.

[0043] For example, when the conjugated diene monomer is 1,3-butadiene, the first conjugated diene polymer may be a polybutadiene prepared by polymerizing 1,3-butadiene to a weight average molecular weight of less than 100,000 g / mol.

[0044] The bioelastic includes units derived from a first conjugated diene based polymer as well as units derived from a vegetable oil.

[0045] Generally, vegetable oils are triglyceride molecules represented by the following chemical formula 1:

[0046] [ka]

[0047] In the above Chemical Formula 1, R1 to R3 are each an ester group derived from a fatty acid, and each is an unsaturated or saturated hydrocarbon group.

[0048] Here, the relative ratio of R1 to R3 may vary depending on the type of vegetable oil, and may be, for example, as shown in Table 1 below.

[0049] [Table 1]

[0050] As another example, the vegetable oil may be an epoxidized vegetable oil. Epoxidized vegetable oil is an organic compound obtained by the epoxidation reaction of vegetable oil, and the degree of epoxidation (epoxy ratio) may vary depending on the type of vegetable oil. The epoxidation of vegetable oil is performed while an oxygen atom is added to an unsaturated bond in a vegetable oil molecule to generate an epoxide, and the degree of epoxidation may be affected by the ratio of unsaturated bonds in the vegetable oil. The epoxidized vegetable oil may be one or more selected from the group consisting of epoxidized soybean oil, epoxidized rapeseed oil, epoxidized canola oil, epoxidized sunflower oil, epoxidized linseed oil, epoxidized rice bran oil, epoxidized palm oil, epoxidized olive oil, epoxidized peanut oil, epoxidized coconut oil, epoxidized cottonseed oil, and epoxidized coconut oil, and may be preferably epoxidized soybean oil, epoxidized cottonseed oil, or a combination thereof, and more preferably epoxidized soybean oil, but is not limited thereto.

[0051] In the present invention, the vegetable oil-derived units may be 1 wt% to 50 wt%, preferably 1 wt% to 30 wt%, or 1 wt% to 20 wt%, based on the total weight of the bioelastic. The content of the vegetable oil-derived units may be determined based on the amount of vegetable oil used in the preparation of the bioelastic, and for example, the content of the vegetable oil-derived units in the bioelastic may be parts by weight of vegetable oil per 100 parts by weight of the conjugated diene monomer used in the preparation of the first conjugated diene polymer.

[0052] Within this range, there is an advantage that bonding with the first conjugated diene polymer is easy and a bioelastic body is efficiently formed.

[0053] In the present invention, the bioelastic may be 5 parts by weight to 50 parts by weight relative to 100 parts by weight of the second conjugated diene polymer in the rubber composition, and specifically, may be 5 parts by weight or more, 7 parts by weight or more, 30 parts by weight or less, 20 parts by weight or less, or 15 parts by weight or less.

[0054] The bioelastic may be present in an amount of 5% to 50% by weight, and preferably 5% to 40% by weight, or 5% to 30% by weight, based on the total weight of the rubber composition.

[0055] Within this range, the bioelastic may exhibit excellent processability for use in a variety of applications, and the rubber composition may exhibit excellent viscoelastic properties and abrasion resistance.

[0056] (b) Second Conjugated Diene Polymer In the present invention, the rubber composition includes a second conjugated diene-based polymer along with a bioelastic.

[0057] The second conjugated diene-based polymer is distinguished from the first conjugated diene-based polymer in that the units derived from the first conjugated diene-based polymer contained in the bioelastic have a higher weight average molecular weight than the first conjugated diene-based polymer, and the units derived from the first conjugated diene-based polymer are bonded to units derived from a vegetable oil within the bioelastic, whereas the second conjugated diene-based polymer is contained as a separate substance from the bioelastic within the rubber composition.

[0058] The second conjugated diene polymer includes a repeating unit derived from a conjugated diene monomer, and the repeating unit derived from the conjugated diene monomer may refer to a repeating unit formed during polymerization of the conjugated diene monomer.

[0059] In addition, the second conjugated diene polymer may further include a repeating unit derived from an aromatic vinyl monomer, in which case the second conjugated diene polymer may be a copolymer including a repeating unit derived from a conjugated diene monomer and a repeating unit derived from an aromatic vinyl monomer. Here, the repeating unit derived from the aromatic vinyl monomer may refer to a repeating unit formed during polymerization of the aromatic vinyl monomer.

[0060] According to an embodiment of the present invention, the conjugated diene monomer may be at least one selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene, isoprene, 2-phenyl-1,3-butadiene, and 2-halo-1,3-butadiene (halo means a halogen atom), but is not limited thereto.

[0061] The aromatic vinyl monomer may be, for example, one or more selected from the group consisting of styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 1-vinylnaphthalene, 4-cyclohexylstyrene, 4-(p-methylphenyl)styrene, 1-vinyl-5-hexylnaphthalene, 3-(2-pyrrolidino ethyl)styrene, 4-(2-pyrrolidino ethyl)styrene, and 3-(2-pyrrolidino-1-methyl ethyl)-methylstyrene, but is not limited thereto.

[0062] The second conjugated diene polymer may be a copolymer further including a repeating unit derived from a diene monomer having 1 to 10 carbon atoms in addition to the repeating unit derived from the conjugated diene monomer. The repeating unit derived from the diene monomer may be a repeating unit derived from a diene monomer different from the conjugated diene monomer, and the diene monomer different from the conjugated diene monomer may be, for example, 1,2-butadiene. When the second conjugated diene polymer is a copolymer further including a diene monomer, the second conjugated diene polymer may include a repeating unit derived from a diene monomer in an amount of more than 0% by weight to 1% by weight, more than 0% by weight to 0.1% by weight, more than 0% by weight to 0.01% by weight, or more than 0% by weight to 0.001% by weight, and within this range, there is an effect of preventing gel formation.

[0063] According to an embodiment of the present invention, the copolymer may be a random copolymer, which has an excellent balance between the physical properties. The random copolymer may mean a copolymer in which repeating units constituting the copolymer are randomly arranged.

[0064] In the present invention, the second conjugated diene polymer may have a number average molecular weight of 1,000 g / mol to 2,000,000 g / mol, 10,000 g / mol to 1,000,000 g / mol, or 100,000 g / mol to 800,000 g / mol. Within this range, the effect of excellent rolling resistance and wet road resistance can be achieved.

[0065] In the present invention, the second conjugated diene polymer may have a weight average molecular weight of 1,000 g / mol to 3,000,000 g / mol, or 10,000 g / mol to 2,000,000 g / mol. Within this range, the effects of excellent rolling resistance, wet road resistance, and abrasion resistance can be achieved.

[0066] In addition, the second conjugated diene polymer may have a vinyl content of 5% by weight or more, 10% by weight or more, 15% by weight or more, 20% by weight or more, 60% by weight or less, 50% by weight or less, 40% by weight or less, or 30% by weight or less, for example, 10% to 60% by weight, 20% to 50% by weight, 20% to 40% by weight, or 20% to 30% by weight. Here, the vinyl content may refer to the content of 1,2-addition conjugated diene monomer, not 1,4-addition, based on the total weight of the second conjugated diene polymer composed of a monomer having a vinyl group and an aromatic vinyl monomer.

[0067] In the present invention, the second conjugated diene polymer may be contained in an amount of 10% by weight or more, 10% by weight to 100% by weight, or 20% by weight to 90% by weight based on the total weight of the rubber composition. Within the above range, the rubber composition may exhibit excellent mechanical properties such as tensile strength and abrasion resistance, and may exhibit an excellent balance between the various physical properties.

[0068] In the present invention, the rubber composition may further contain other rubber components, if necessary, in addition to the second conjugated diene-based polymer.

[0069] The other rubber component may be included in an amount of 90% by weight or less based on the total weight of the rubber composition. As a specific example, the other rubber component may be included in an amount of 1 part by weight to 900 parts by weight based on 100 parts by weight of the second conjugated diene polymer.

[0070] The rubber component may be, for example, natural rubber or synthetic rubber, and specific examples thereof include natural rubber (NR) containing cis-1,4-polyisoprene; modified natural rubbers such as epoxidized natural rubber (ENR), deproteinized natural rubber (DPNR), and hydrogenated natural rubber obtained by modifying or refining the general natural rubber; styrene-butadiene copolymer (SBR), polybutadiene (BR), polyisoprene (IR), butyl rubber (IIR), ethylene-propylene copolymer, polyisobutylene-co-isoprene, It may be a synthetic rubber such as neoprene, poly(ethylene-co-propylene), poly(styrene-co-butadiene), poly(styrene-co-isoprene), poly(styrene-co-isoprene-co-butadiene), poly(isoprene-co-butadiene), poly(ethylene-co-propylene-codiene), polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, halogenated butyl rubber, or the like, and any one or a mixture of two or more of these may be used.

[0071] In the present invention, the rubber composition may further contain a filler, and the amount of the filler may be 0.1 to 200 parts by weight, or 10 to 120 parts by weight, based on 100 parts by weight of the second conjugated diene polymer.

[0072] The filler may be, for example, a silica-based filler, and specific examples thereof may include wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, colloidal silica, etc., and preferably wet silica, which is the most excellent in both improving fracture properties and wet grip properties. In addition, the rubber composition may further contain a carbon-based filler as necessary.

[0073] When silica is used as the filler, a silane coupling agent for improving reinforcement and low heat generation may be used together. Specific examples of the silane coupling agent include bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-mercaptopropyltriethoxysilane ... -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-mercaptopropyl dimethoxymethylsilane, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide or dimethoxymethylsilylpropyl benzothiazolyl tetrasulfide, and any one or a mixture of two or more of these may be used. Preferably, in consideration of the effect of improving the reinforcing property, it may be bis(3-triethoxysilylpropyl) polysulfide or 3-trimethoxysilylpropyl benzothiazyl tetrasulfide.

[0074] The silane coupling agent can be used in an amount of 1 to 20 parts by weight, or 5 to 15 parts by weight, per 100 parts by weight of silica. Within this range, the effect of the coupling agent is fully exerted, and the effect of preventing gelation of the rubber component is also achieved.

[0075] In the present invention, the rubber composition may be sulfur crosslinkable and may further contain a vulcanizing agent. The vulcanizing agent may be specifically sulfur powder and may be contained in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the rubber component. Within this range, the vulcanized rubber composition has the effect of ensuring the elastic modulus and strength required for the vulcanized rubber composition and excellent fuel economy.

[0076] In the present invention, the rubber composition may further contain, in addition to the above-mentioned components, various additives generally used in the rubber industry, specifically, a vulcanization accelerator, a process oil, an antioxidant, a plasticizer, an anti-aging agent, a scorch inhibitor, zinc white, stearic acid, a thermosetting resin, or a thermoplastic resin.

[0077] The vulcanization accelerator may be, for example, a thiazole-based compound such as M (2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), or CZ (N-cyclohexyl-2-benzothiazyl sulfenamide), or a guanidine-based compound such as DPG (diphenyl guanidine), and may be included in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the rubber component.

[0078] The process oil acts as a softener in the rubber composition, and may be, for example, a paraffinic, naphthenic, or aromatic compound, and when considering tensile strength and abrasion resistance, aromatic process oils may be used, and when considering hysteresis loss and low temperature properties, naphthenic or paraffinic process oils may be used. The process oil may be contained in an amount of 100 parts by weight or less per 100 parts by weight of the rubber component, and within this range, it is effective in preventing a decrease in the tensile strength and low heat generation property (fuel economy) of the vulcanized rubber.

[0079] The antioxidant may be, for example, 2,6-di-t-butyl-paracresol, dibutylhydroxytoluene, 2,6-bis((dodecylthio)methyl)-4-nonylphenol, or 2-methyl-4,6-bis((octylthio)methyl)phenol, and may be used in an amount of 0.1 to 6 parts by weight based on 100 parts by weight of the rubber component.

[0080] The antioxidant may be, for example, N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, or a high-temperature condensate of diphenylamine and acetone, and may be used in an amount of 0.1 to 6 parts by weight based on 100 parts by weight of the rubber component.

[0081] In the present invention, the rubber composition can be obtained by kneading using a kneading machine such as a Banbury mixer, a roll, or an internal mixer according to the compounding recipe, and after molding, a rubber composition having low heat buildup and excellent abrasion resistance can be obtained by a vulcanization process.

[0082] As a result, the rubber composition can be useful for producing various tire components such as tire treads, undertreads, sidewalls, carcass coating rubber, belt coating rubber, bead fillers, chafers, and bead coating rubber, as well as various industrial rubber products such as dustproof rubber, belt conveyors, and hoses.

[0083] Method for producing rubber composition The method for producing a rubber composition of the present invention includes the steps of: (S1) preparing a bioelastic containing units derived from a first conjugated diene polymer and units derived from a vegetable oil, the first conjugated diene polymer having a weight average molecular weight of less than 100,000 g / mol; (S2) polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in a hydrocarbon solvent in the presence of a polymerization initiator to produce a second conjugated diene polymer; and (S3) mixing the bioelastic with the second conjugated diene polymer.

[0084] The bioelastomer, the first conjugated diene based polymer, the vegetable oil, and the second conjugated diene based polymer are as described above.

[0085] Step (S1) In step (S1), a bioelastic is prepared, the bioelastic comprising a first conjugated diene polymer-derived unit and a vegetable oil-derived unit, the first conjugated diene polymer having a weight average molecular weight of less than 100,000 g / mol.

[0086] For example, the step (S1) may include a step of polymerizing a conjugated diene monomer to produce an activated polymer having a weight average molecular weight of less than 100,000 g / mol, and a step of reacting the activated polymer with a vegetable oil.

[0087] Here, the conjugated diene monomer may be at least one selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene, isoprene, 2-phenyl-1,3-butadiene, and 2-halo-1,3-butadiene (halo means a halogen atom), specifically, 1,3-butadiene, but is not limited thereto.

[0088] In the present invention, the vegetable oil may be 0.1 to 50 parts by weight, and may be 0.1 or more, 1 or more, 3 or more, 50 or less, 30 or less, 20 or less, or 15 or less, based on 100 parts by weight of the conjugated diene monomer. Within this range, the activated polymer and the vegetable oil react with excellent efficiency, and a bioelastic containing a unit derived from the first conjugated diene polymer and a unit derived from the vegetable oil can be easily produced.

[0089] Step (S2) In step (S2), a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer are polymerized in a hydrocarbon solvent in the presence of a polymerization initiator to produce a second conjugated diene polymer.

[0090] The hydrocarbon solvent is not particularly limited, and may be, for example, one or more selected from the group consisting of n-pentane, n-hexane, n-heptane, isooctane, cyclohexane, toluene, benzene, and xylene.

[0091] In the present invention, the polymerization initiator can be used in an amount of 0.01 mmol to 10 mmol, 0.05 mmol to 5 mmol, 0.1 mmol to 2 mmol, 0.1 mmol to 1 mmol, or 0.15 to 0.8 mmol, based on 100 g of the total monomers.

[0092] The polymerization initiator is not particularly limited, and may be, for example, one or more selected from the group consisting of methyl lithium, ethyl lithium, propyl lithium, n-butyl lithium, s-butyl lithium, t-butyl lithium, hexyl lithium, n-decyl lithium, t-octyl lithium, phenyl lithium, 1-naphthyl lithium, n-eicosyl lithium, 4-butylphenyl lithium, 4-tolyl lithium, cyclohexyl lithium, 3-5-di-n-heptylcyclohexyl lithium, 4-cyclopentyl lithium, naphthyl sodium, naphthyl potassium, lithium alkoxide, sodium alkoxide, potassium alkoxide, lithium sulfonate, sodium sulfonate, potassium sulfonate, lithium amide, sodium amide, potassium amide, and lithium isopropyl amide.

[0093] In the present invention, the polymerization in step (S2) may be, for example, an anionic polymerization, and for a specific example, a living anionic polymerization having an anionic active site at the polymerization end by a growth polymerization reaction by an anion. The polymerization in step (S1) may be a temperature-rise polymerization, an isothermal polymerization, or a constant temperature polymerization (adiabatic polymerization), and the constant temperature polymerization may mean a polymerization method including a step of polymerizing by self-reaction heat without adding heat after adding a polymerization initiator, the temperature-rise polymerization may mean a polymerization method of increasing the temperature by adding heat after adding the polymerization initiator, and the isothermal polymerization may mean a polymerization method of increasing the temperature by adding heat or removing heat after adding the polymerization initiator to maintain the temperature of the polymer constant.

[0094] The polymerization in step (S2) may be carried out by further including a diene compound having 1 to 10 carbon atoms in addition to the conjugated diene monomer, and in this case, there is an effect of preventing gel formation on the wall of the reactor during long-term operation. An example of the diene compound may be 1,2-butadiene.

[0095] The polymerization in step (S2) may be carried out at a temperature range of, for example, 80° C. or less, −20 to 80° C., 0 to 80° C., 0 to 70° C., or 10 to 70° C., and within this range, the molecular weight distribution of the polymer can be narrowly controlled, and there is an excellent effect of improving physical properties.

[0096] Meanwhile, the polymerization in step (S2) may be carried out by including a polar additive, and the polar additive may be added in a ratio of 0.001 g to 50 g, 0.001 g to 10 g, or 0.005 g to 0.1 g, based on 100 g of the total monomers. As yet another example, the polar additive may be added in a ratio of 0.001 g to 10 g, 0.005 g to 5 g, or 0.005 g to 4 g, based on 1 mmol of the total organolithium compound.

[0097] The polar additive may be, for example, one or more selected from the group consisting of tetrahydrofuran, 2,2-di(2-tetrahydrofuryl)propane, diethyl ether, cyclopentyl ether, dipropyl ether, ethylene methyl ether, ethylene dimethyl ether, diethyl glycol, dimethyl ether, tert-butoxyethoxyethane, bis(3-dimethylaminoethyl)ether, (dimethylaminoethyl)ethyl ether, trimethylamine, triethylamine, tripropylamine, N,N,N',N'-tetramethylethylenediamine, sodium mentholate, and 2-ethyl tetrahydrofurfuryl ether, and is preferably one or more selected from the group consisting of triethylamine, tetramethylethylenediamine, sodium mentholate, or 2-ethyl tetrahydrofurfuryl ether. In the case where the polar additive is contained, when a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer are copolymerized, the polar additive has an effect of inducing the easy formation of a random copolymer by complementing the difference in reaction rate.

[0098] The step (S2) may include a step of preparing an activated polymer by polymerization of a conjugated diene monomer or copolymerization of a conjugated diene monomer and an aromatic vinyl monomer, and then terminating the reaction. Here, the activated polymer may refer to a polymer in which a polymer anion and an organometallic cation are bonded.

[0099] Alternatively, the step (S2) may include a step of preparing an activated polymer and then reacting or coupling the activated polymer with a modifier. The modifier may be used in an amount of 0.01 mmol to 10 mmol per 100 g of total monomers. As yet another example, the modifier may be used in a molar ratio of 1:0.1 to 10, 1:0.1 to 5, or 1:0.1 to 1:3 per mole of the polymerization initiator in the step (S2).

[0100] Step (S3) The step (S3) is a step for preparing a rubber composition, which can be performed by mixing the bioelastomer prepared in step (S1) and the second conjugated diene-based polymer prepared in step (S2).

[0101] The present invention also provides a tire produced using the rubber composition.

[0102] The tire may include a tire or a tire tread.

[0103] Working Example The present invention will be described in more detail with reference to the following examples. However, the following examples are for illustrating the present invention and are not intended to limit the scope of the present invention.

[0104] [Production of bioelastics] Manufacturing Example 1 In a 2L autoclave reactor, 700g of n-hexane, 100g of 1,3-butadiene, and 0.4g of 2,2-bis(2-oxolanyl)propane as a polar additive were added, and then 16.4g of n-butyllithium (6% by weight in hexane) was added, and the internal temperature of the reactor was adjusted to 50°C to carry out an adiabatic heating reaction. A further adiabatic heating reaction was carried out at 60°C for about 30 minutes to produce a first conjugated diene polymer. Here, after the reaction, a part of the polymer was collected and used as a sample for measuring the weight average molecular weight of the first conjugated diene polymer chain. Here, the sample was prepared by drying the polymer in an oven at 140°C to remove the remaining solvent, and then dissolving it in THF before use.

[0105] Next, 5g of soybean oil was added and mixed at 70℃ for 20 minutes. The reaction was stopped using ethanol, and 3g of a solution of 30% by weight of antioxidant Wingstay K dissolved in hexane was added. The obtained polymer was placed in hot water heated with steam and stirred to remove the solvent, and then roll-dried to remove the remaining solvent and water, producing a bio-elastic material.

[0106] Manufacturing Example 2 A bioelastic was prepared in the same manner as in Preparation Example 1, except that 5 g of epoxidized soybean oil was used instead of 5 g of soybean oil.

[0107] Production Example 3 Into a 2L autoclave reactor, 700g of N-hexane, 100g of 1,3-butadiene, and 0.03g of 2,2-bis(2-oxolanyl)propane as a polar additive were added, and then 16.4g of n-butyllithium (6% by weight in hexane) was added, and the internal temperature of the reactor was adjusted to 60°C to carry out an adiabatic heating reaction. The adiabatic heating reaction was further carried out at 70°C for about 30 minutes. Here, after the reaction, a portion of the polymer was collected and used as a sample for measuring the weight average molecular weight of the first conjugated diene polymer chain.

[0108] Next, 5g of soybean oil was added and mixed at 70℃ for 20 minutes. The reaction was stopped using ethanol, and 3g of a solution of 30% by weight of antioxidant Wingstay K dissolved in hexane was added. The obtained polymer was placed in hot water heated with steam and stirred to remove the solvent, and then roll-dried to remove the remaining solvent and water, producing a bio-elastic material.

[0109] Production Example 4 A bioelastic was prepared in the same manner as in Preparation Example 3, except that 5 g of epoxidized soybean oil was used instead of 5 g of soybean oil.

[0110] Production Example 5 A bioelastic was prepared in the same manner as in Preparation Example 3, except that 10 g of soybean oil was used instead of 5 g of soybean oil.

[0111] Comparative Manufacturing Example 1 In a 2L autoclave reactor, 700g of n-hexane, 100g of 1,3-butadiene, and 0.4g of 2,2-bis(2-oxolanyl)propane as a polar additive were added, followed by 16.4g of n-butyllithium (6% by weight in hexane), and the internal temperature of the reactor was adjusted to 50°C to carry out an adiabatic heating reaction. The adiabatic heating reaction was further carried out at 60°C for about 30 minutes. The reaction was stopped using ethanol, and 3g of a solution in which the antioxidant Wingstay K was dissolved in hexane at 30% by weight was added. The obtained polymer was placed in hot water heated with steam, stirred to remove the solvent, and roll-dried to remove the remaining solvent and water, producing a liquid polymer.

[0112] Comparative Manufacturing Example 2 In a 2L autoclave reactor, 700g of n-hexane, 100g of 1,3-butadiene, and 0.03g of 2,2-bis(2-oxolanyl)propane as a polar additive were added, followed by 16.4g of n-butyllithium (6% by weight in hexane), and the internal temperature of the reactor was adjusted to 60°C to carry out an adiabatic heating reaction. The adiabatic heating reaction was further carried out at 70°C for about 30 minutes. The reaction was stopped using ethanol, and 3g of a solution in which the antioxidant Wingstay K was dissolved in hexane at 30% by weight was added. The obtained polymer was placed in hot water heated with steam, stirred to remove the solvent, and roll-dried to remove the remaining solvent and water, producing a liquid polymer.

[0113] [Analysis of bioelastics] Experimental Example 1 1) Vinyl content (wt%) The vinyl content in each of the polymers was measured and analyzed using a Varian VNMRS 500 MHz NMR.

[0114] In the NMR measurement, 1,1,2,2-tetrachloroethane was used as the solvent, and the vinyl content was calculated based on the solvent peak at 5.97 ppm, with 75.8 to 5.1 ppm representing 1,4-vinyl and 1,2-vinyl peaks, and 5.1 to 4.5 ppm representing 1,2-vinyl peaks.

[0115] 2) Weight average molecular weight (Mw, X10 3 g / mol), number average molecular weight (Mn, 3 g / mol) and molecular weight distribution (PDI, MWD) The weight average molecular weight (Mw) and number average molecular weight (Mn) were measured under the following conditions using a GPC (gel permeation chromatograph) (PL GPC220, Agilent Technologies), and a molecular weight distribution curve was obtained. The molecular weight distributions (PDI, MWD, Mw / Mn) were calculated from the measured molecular weights.

[0116] -Column: Two PLgel Olexis (Polymer Laboratories) columns and one PLgel mixed-C (Polymer Laboratories) column were used in combination. -Solvent: 2% by weight of amine compound mixed in tetrahydrofuran -Flow rate: 1ml / min -Sample concentration: 1-2mg / ml (diluted in THF) -Injection volume: 100μl -Column temperature: 40℃ -Detector: Refractive index -Standard: Polystyrene (corrected by a cubic function)

[0117] [Table 2]

[0118] As a result of the above, it was confirmed that the bioelastic used in the present invention contains units derived from a first conjugated diene polymer having a weight average molecular weight of 100,000 g / mol or less.

[0119] [Production of rubber composition] Example 1 Rubber test pieces were produced using SSBR F3626Y manufactured by LG Chemical as the second conjugated diene polymer as the raw rubber and the compounding method (A) in Table 3 below. The raw material contents in the table below are shown in parts by weight based on 100 parts by weight of the raw rubber.

[0120] [Table 3]

[0121] Specifically, the rubber test pieces are mixed in a first stage and a second stage. In the first stage, raw rubber, silica (filler), an organic silane coupling agent (X50S, Evonik), the bioelastic material according to Preparation Example 1, a zincating agent (ZnO), stearic acid, an antioxidant (TMQ(RD) (2,2,4-trimethyl-1,2-dihydroquinoline polymer), an anti-aging agent (6PPD ((dimethylbutyl)-N-phenyl-phenylenediamine)) and a wax (Microcrystaline)) are mixed in a Banbury mixer equipped with a temperature control device. Wax) was mixed. Here, the initial temperature of the mixer was controlled at 70°C, and after the mixing was completed, the primary compound was obtained at a discharge temperature of 145 to 155°C. In the second mixing stage, the primary compound was cooled to room temperature, and then the primary compound, sulfur, rubber accelerator (DPD (diphenylguanine)) and vulcanization accelerator (CZ (N-cyclohexyl-2-benzothiazylsulfenamide)) were added to the mixer and mixed at a temperature of 100°C or less to obtain a secondary compound. Next, a curing process was performed at 160°C for 20 minutes to produce a rubber test piece.

[0122] Example 2 Rubber specimens were prepared similarly to Example 1, except that the bioelastic of Preparative Example 2 was used instead of the bioelastic of Preparative Example 1.

[0123] Example 3 Rubber specimens were prepared similarly to Example 1, except that the bioelastic of Preparative Example 3 was used instead of the bioelastic of Preparative Example 1.

[0124] Example 4 Rubber specimens were prepared similarly to Example 1, except that the bioelastic of Preparative Example 4 was used instead of the bioelastic of Preparative Example 1.

[0125] Example 5 Rubber specimens were prepared similarly to Example 1, except that the bioelastic of Preparative Example 5 was used instead of the bioelastic of Preparative Example 1.

[0126] Comparative Example 1 Rubber test pieces were produced in the same manner as in Example 1, except that the compounding method (ii) in Table 3 was used.

[0127] Comparative Example 2 Rubber specimens were prepared as in Example 1, except that the liquid polymer of Comparative Preparation Example 1 was used instead of the bioelastomer of Preparation Example 1.

[0128] Comparative Example 3 Rubber specimens were prepared as in Example 1, except that the liquid polymer of Comparative Preparation Example 2 was used instead of the bioelastomer of Preparation Example 1.

[0129] [Analysis of rubber composition] Experimental Example 2 1) Viscoelastic properties The viscoelastic properties were measured using a dynamic mechanical analyzer (manufactured by GABO) in Film Tension mode at a frequency of 10 Hz and a measurement temperature of 60°C, and the tan δ value was confirmed. The lower the 60°C tan δ value in the measured values, the lower the hysteresis loss and the better the low running resistance (fuel economy). After specifying the viscoelastic property standard value (Comparative Example 1), the value was indexed (%) and described so that the higher the value, the better the performance.

[0130] 2) Abrasion resistance A DIN abrasion test was performed on each rubber test piece in accordance with ASTM D5963, and the results were expressed as a DIN loss index (loss volume index: ARIA (Abration resistance index, Method A)) based on the measured value of Comparative Example 1. A higher value indicates better performance.

[0131] [Table 4]

[0132] As shown in the above results, it was confirmed that Examples 1 to 5 exhibited viscoelastic properties and abrasion resistance at a well-balanced and excellent level. Meanwhile, Comparative Example 1 used process oil instead of a bioelastic material, and in this case, it was found that the viscoelastic properties and abrasion resistance were somewhat lower than those of the Examples. Also, Comparative Example 2 used the mixture of Comparative Preparation Example 1 instead of a bioelastic material, and Comparative Example 3 used the mixture of Comparative Preparation Example 2, but both Comparative Examples 2 and 3 showed significantly lower viscoelastic properties.

[0133] Experimental Example 3 The aging properties were confirmed by observing the change in tensile properties before and after heat aging of each rubber test piece. Since no change was observed before and after aging, it was confirmed that the aging properties were excellent.

[0134] Specifically, each rubber test piece was left at 100°C for 24 hours to undergo heat aging, and the tensile stress of each rubber test piece was measured at room temperature before and after aging in accordance with the tensile test method of ASTM 412 using a Universal Test Machine 4204 (manufactured by Instron).

[0135] Here, the tensile stress values ​​before and after aging are shown, and the ratio of the tensile stress value after aging to the value before aging is calculated and shown together.

[0136] [Table 5]

[0137] As shown by the above results, it was confirmed that the rubber compositions of Examples 1 to 5 had improved aging properties and smaller changes in tensile properties before and after aging compared to the rubber compositions of Comparative Examples 1 to 3. In this way, it was confirmed that the rubber composition of the present invention exhibits uniformly excellent viscoelastic properties, abrasion resistance, and aging properties by containing a bioelastic containing units derived from a first conjugated diene polymer having a weight average molecular weight of less than 100,000 g / mol and units derived from a vegetable oil, and a second conjugated diene polymer.

Claims

1. (a) a bioelastic comprising a first conjugated diene polymer derived unit and a vegetable oil derived unit, the first conjugated diene polymer having a weight average molecular weight of less than 100,000 g / mol; (b) a second conjugated diene-based polymer having a weight average molecular weight higher than that of the first conjugated diene-based polymer, the second conjugated diene polymer contains a repeating unit derived from a conjugated diene monomer and a repeating unit derived from an aromatic vinyl monomer, The rubber composition comprises 5 to 50 parts by weight of the bioelastic per 100 parts by weight of the second conjugated diene-based polymer.

2. The rubber composition according to claim 1, wherein the first conjugated diene-based polymer has a weight average molecular weight of 1,000 g / mol to 80,000 g / mol.

3. The rubber composition according to claim 1, wherein the vegetable oil is at least one selected from the group consisting of soybean oil, rapeseed oil, canola oil, sunflower oil, linseed oil, rice bran oil, palm oil, olive oil, peanut oil, coconut oil, cottonseed oil and coconut oil.

4. The rubber composition according to claim 1, wherein the vegetable oil is an epoxidized vegetable oil, and is at least one selected from the group consisting of epoxidized soybean oil, epoxidized rapeseed oil, epoxidized canola oil, epoxidized sunflower oil, epoxidized linseed oil, epoxidized rice bran oil, epoxidized palm oil, epoxidized olive oil, epoxidized peanut oil, epoxidized coconut oil, epoxidized cottonseed oil, and epoxidized coconut oil.

5. The rubber composition of claim 1 further comprising a filler.

6. The rubber composition according to claim 5 , wherein the filler is at least one selected from the group consisting of silica-based fillers and carbon black-based fillers.

7. (S1) preparing a bioelastic comprising a first conjugated diene polymer-derived unit and a vegetable oil-derived unit, the first conjugated diene polymer having a weight average molecular weight of less than 100,000 g / mol; (S2) polymerizing a conjugated diene monomer and an aromatic vinyl monomer in a hydrocarbon solvent in the presence of a polymerization initiator to produce a second conjugated diene polymer having a weight average molecular weight higher than that of the first conjugated diene polymer; (S3) mixing the bioelastomer with a second conjugated diene based polymer; The method for producing a rubber composition, wherein the bioelastic is 5 to 50 parts by weight based on 100 parts by weight of the second conjugated diene-based polymer.

8. 8. The method for producing a rubber composition according to claim 7, wherein the step (S1) includes the steps of: polymerizing a conjugated diene monomer to produce an activated polymer having a weight average molecular weight of less than 100,000 g / mol; and reacting the activated polymer with a vegetable oil.

9. The method for producing a rubber composition according to claim 8, wherein the vegetable oil is used in an amount of 0.1 to 50 parts by weight based on 100 parts by weight of the conjugated diene monomer.

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