Rubber composition and tire

Abstract

To provide a rubber composition that exhibits excellent breaking elongation and breaking strength after vulcanization, and exhibiting excellent wetting performance and low fuel consumption when formed into a tire, as well as, a tire manufactured by using the rubber composition.SOLUTION: A rubber composition is characterized by containing 100 pts.mass of a diene-based rubber and 1 to 60 pts.mass of a polyurethane-based oligomer, and the polyurethane-based oligomer combines a diene-based polymer having a hydroxyl group, a polyisocyanate, and a polyamine are polymerized at a molar ratio of the isocyanate group to the active hydrogen group of 0.3 to 1.0, has a weight average molecular weight of 3,000 to 50,000, has an urethane bond and an urea bond, and a molar ratio of the urethane bond and the urea bond is 0.1 to 3.0.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a rubber composition and a tire.

Background Art

[0002] Conventionally, as a rubber composition used for tires and the like, a rubber composition containing a diene rubber is known. For example, Patent Document 1 discloses a rubber composition containing a diene rubber and a polymer having a segment of a urethane skeleton and a segment of a diene skeleton in one molecule (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Recently, for rubber compositions used for tires (especially treads), from the viewpoint of reducing the environmental load and the like, further improvement in low fuel consumption performance when made into tires has been demanded. Also, from the viewpoints of safety and the like, further improvement in breaking strength and breaking elongation after vulcanization, and wet performance when made into tires has been demanded. Under such circumstances, when the present inventors examined the rubber composition described in Patent Document 1, it became clear that the breaking elongation and breaking strength, as well as the wet performance and low fuel consumption performance, do not necessarily meet the levels required recently.

[0005] Therefore, in view of the above circumstances, an object of the present invention is to provide a rubber composition that exhibits excellent breaking elongation and breaking strength after vulcanization, and excellent wet performance and low fuel consumption performance when made into a tire, and a tire manufactured using the above rubber composition.

Means for Solving the Problems

[0006] As a result of diligent research into the above-mentioned problems, the inventors of this invention discovered that these problems can be solved by incorporating a specific polyurethane oligomer having urethane bonds and urea bonds, leading to the present invention. In other words, the inventors have found that the above problem can be solved by the following configuration.

[0007] (1) Containing 100 parts by mass of diene rubber and 1 to 60 parts by mass of polyurethane oligomer, The above polyurethane oligomers This is a polymer obtained by polymerizing a diene polymer having a hydroxyl group, a polyisocyanate, and a polyamine in a ratio such that the molar ratio of isocyanate groups to active hydrogen groups is 0.3 to 1.0. The weight-average molecular weight is 3,000 to 50,000. A rubber composition having urethane bonds and urea bonds, wherein the molar ratio of the urea bonds to the urethane bonds is 0.1 to 3.0. (2) The rubber composition according to (1) above, wherein the total proportion of the portion derived from the polyisocyanate and the portion derived from the polyamine to the entire polyurethane oligomer is 6 to 40% by mass. (3) The rubber composition according to (1) or (2) above, wherein the diene polymer having a hydroxyl group comprises at least one selected from the group consisting of polybutadiene polyol, hydrogenated polybutadiene polyol, and polyisoprene polyol. (4) The rubber composition according to any one of (1) to (3) above, further comprising 1 to 100 parts by mass of at least one filler selected from the group consisting of carbon black and white fillers. (5) The rubber composition according to any one of (1) to (4) above, wherein the number average molecular weight of the polyamine is 50 to 500. (6) The rubber composition according to any one of (1) to (5) above, further comprising 30 to 100 parts by mass of silica as a white filler. (7) A tire manufactured using any of the rubber compositions described in (1) to (6) above. [Effects of the Invention]

[0008] As described below, the object of the present invention is to provide a rubber composition that exhibits excellent elongation and strength after vulcanization, and excellent wet performance and fuel efficiency when made into a tire, as well as a tire manufactured using the above rubber composition. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic partial cross-sectional view showing an example of an embodiment of the tire of the present invention. [Modes for carrying out the invention]

[0010] The rubber composition and tire of the present invention will be described below. In this specification, numerical ranges represented by "~" mean a range that includes the numbers written before and after "~" as the lower and upper limits, respectively. Furthermore, each component may be used alone or in combination of two or more. When two or more components are used in combination, the "content" of each component refers to the total content unless otherwise specified. Furthermore, the breaking strength after vulcanization is simply called "breaking strength," the elongation at break after vulcanization is simply called "elongation at break," the wet performance when made into a tire is simply called "wet performance," and the fuel efficiency when made into a tire is simply called "fuel efficiency." Furthermore, the superior tensile strength (high tensile strength), superior tensile elongation (high tensile elongation), superior wet performance, and superior fuel efficiency are collectively referred to as "the superior effects of the present invention."

[0011] [1] Rubber composition The rubber composition of the present invention (hereinafter also simply referred to as "the composition of the present invention") It contains 100 parts by mass of a diene rubber and 1 to 60 parts by mass of a polyurethane oligomer, where the above polyurethane oligomer (hereinafter also referred to as "specific oligomer") is a polymer obtained by polymerizing a diene polymer having a hydroxy group, a polyisocyanate, and a polyamine at a ratio such that the molar ratio of the isocyanate group to the active hydrogen group is 0.3 to 1.0, has a weight average molecular weight of 3,000 to 50,000, and is a rubber composition having urethane bonds and urea bonds, and the molar ratio of the urea bonds to the urethane bonds is 0.1 to 3.0.

[0012] The composition of the present invention is considered to be able to solve the above-described problems because it has such a configuration. Although the reason is not clear, it is presumably as follows. The specific oligomer contained in the composition of the present invention is a polymer obtained by polymerizing a diene polymer having a hydroxy group, a polyisocyanate, and a polyamine. Therefore, the specific oligomer has a soft portion (soft segment) derived from the diene polymer and a hard portion (hard segment) derived from the polyisocyanate and the polyamine. The soft segment is considered to contribute to the affinity with the diene rubber, and the hard segment is considered to contribute to the mechanical properties (tensile strength, elongation at break). Further, the above hydroxy group reacts with the isocyanate group of the polyisocyanate to form a urethane bond (-NH-COO-), and the amino group of the polyamine reacts with the isocyanate group of the polyisocyanate to form a urea bond (-NH-CO-NH-). Urethane bonds and urea bonds are considered to form aggregates by hydrogen bonds. The aggregates are also considered to contribute to the mechanical properties. Since the composition of the present invention contains such a specific oligomer, it is considered to have excellent mechanical properties. Also, it is considered that the effect of hydrogen bonding of the specific oligomer leads to an increase in tanδ(0°C) (excellent wet characteristics). On the other hand, since the soft segment of the specific oligomer has a high affinity for diene rubber, in the composition of the present invention, it is considered that the specific oligomer has a high dispersibility in the diene rubber. Therefore, it is considered that the energy loss due to the hard segment is small (low fuel consumption performance can be maintained).

[0013] Hereinafter, each component contained in the composition of the present invention will be described.

[0014] [Diene rubber] The diene rubber contained in the composition of the present invention is not particularly limited. The composition of the present invention may contain one kind of diene rubber or two or more kinds of diene rubber. In addition, in this specification, the specific oligomer is not included in the diene rubber.

[0015] [Specific examples] Specific examples of the above diene rubber include natural rubber (NR), butadiene rubber (BR), aromatic vinyl-conjugated diene copolymer rubber, isoprene rubber (IR), acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), chloroprene rubber (CR), etc. Specific examples of the above aromatic vinyl-conjugated diene copolymer rubber include styrene butadiene rubber (SBR), styrene isoprene copolymer rubber, etc. The above diene rubber preferably contains at least one selected from the group consisting of butadiene rubber, styrene butadiene rubber, isoprene rubber and natural rubber, and more preferably contains styrene butadiene rubber, because the effects of the present invention are more excellent.

[0016] If the above diene rubber contains SBR, the SBR content is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more, for the reasons that the effects of the present invention are superior. There is no particular upper limit, and it is 100% by mass.

[0017] [Molecular weight] The number-average molecular weight (Mn) of the above diene rubber is not particularly limited, but for reasons that the effects of the present invention are superior, it is preferably 50,000 to 2,500,000, more preferably 100,000 to 1,500,000, and even more preferably 150,000 to 1,000,000. The weight-average molecular weight (Mw) of the above diene rubber is not particularly limited, but for the reasons that the effects of the present invention are superior, it is preferably 100,000 to 5,000,000, more preferably 200,000 to 3,000,000, and even more preferably 300,000 to 2,000,000.

[0018] In this specification, Mn and Mw are standard polystyrene equivalent values ​​obtained by gel permeation chromatography (GPC) measurement under the following conditions. • Solvent: tetrahydrofuran • Detector: RI detector

[0019] [Specific oligomers] As described above, the composition of the present invention contains a polyurethane oligomer (specific oligomer). Here, specific oligomers are This is a polymer obtained by polymerizing a diene polymer having a hydroxyl group, a polyisocyanate, and a polyamine in a ratio such that the molar ratio of isocyanate groups to active hydrogen groups is 0.3 to 1.0. The weight-average molecular weight is 3,000 to 50,000. It has urethane bonds and urea bonds, and the molar ratio of the urea bonds to the urethane bonds is 0.1 to 3.0.

[0020] [Specific diene polymers] The diene polymer having a hydroxyl group (hereinafter also referred to as "specific diene polymer") used in the production of specific oligomers is not particularly limited.

[0021] The diene polymer of the specific diene polymer is not particularly limited, but specific examples include polybutadiene, polyisoprene, aromatic vinyl-conjugated diene copolymers (e.g., styrene-butadiene copolymers), acrylonitrile-butadiene copolymers, etc. Among these, polybutadiene and polyisoprene are preferred, and polyisoprene is more preferred, because the effects of the present invention are superior. The diene polymer in the specified diene polymer may be a hydrogenated (hydrogenated) product.

[0022] The specific diene polymer preferably has two or more of the above-mentioned hydroxyl groups, for which the effects of the present invention are superior.

[0023] The specific diene polymer preferably contains at least one selected from the group consisting of polybutadiene polyol, hydrogenated polybutadiene polyol, and polyisoprene polyol, for better effects of the present invention, more preferably contains at least one selected from the group consisting of polybutadiene polyol and polyisoprene polyol, and even more preferably contains polyisoprene polyol.

[0024] <Molecular weight> The number-average molecular weight (Mn) of the specific diene polymer is preferably 500 to 20,000, and more preferably 1,000 to 10,000, for the reasons that the effects of the present invention are superior.

[0025] [Polyisocyanate] The polyisocyanates used in the manufacture of specific oligomers are not particularly limited as long as they are compounds having two or more isocyanate groups (-NCO). Specific examples of polyisocyanates include aromatic polyisocyanates such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI; e.g., 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate), 1,4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, xylylene diisocyanate (XDI), tetramethyl xylylene diisocyanate (TMXDI), tollidine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), and triphenylmethane triisocyanate; Hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate, norbornane diisocyanate (NBDI), transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), bis(isocyanate-methyl)cyclohexane (H6XDI), dicyclohexylmethane diisocyanate (H 12 Aliphatic polyisocyanates (including alicyclic polyisocyanates), such as MDI; These carbodiimide-modified polyisocyanates; These are examples of isocyanurate-modified polyisocyanates.

[0026] For the sake of superior effects of the present invention, aromatic polyisocyanates are preferred, and MDI is even more preferred. For the sake of providing superior effects in the present invention, carbodiimide-modified polyisocyanates are preferred.

[0027] <Molecular weight> The number-average molecular weight (Mn) of the polyisocyanate is preferably 50 to 2,000, and more preferably 100 to 1,000, for better performance of the present invention.

[0028] [Polyamines] The polyamine used in the manufacture of specific oligomers is not particularly limited as long as it is a compound having two or more amino groups (-NH2). Specific examples of polyamines include aliphatic polyamines such as ethylenediamine, propylenediamine, butylenediamine, diethylenetriamine, triethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexamethylenediamine, trimethylhexamethylenediamine, 1,2-propanediamine, iminobispropylamine, methyliminobispropylamine, and 1,5-diamino-2-methylpentane (MPMD, manufactured by DuPont Japan); metaphenylenediamine, orthophenylenediamine, paraphenylenediamine, m-xylylenediamine (MXDA), diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiethyldiphenylmethane, diethylmethylbenzenediamine, dimethylthiotoluenediamine (HeartCure 30, manufactured by Kumiai Chemical Co., Ltd.), 4,4'-methylenebis(2-chloroaniline), and 4,4'-methylenebis(3-chloro-2,6-diethylaniline). Aromatic polyamines such as limethylenebis(4-aminobenzoate) and bis(4-amino-2,3-dichlorophenyl)methane; N-aminoethylpiperazine; diamines with a polyether skeleton, exemplified by Jeffermin EDR148 manufactured by Sun Techno Chemical; isophorone diamine, 1,3-bisaminomethylcyclohexane (1,3BAC, manufactured by Mitsubishi Gas Chemical Co., Ltd.), 1-cyclohexylamino-3-aminopropane, 3-aminomethyl-3,3,5-trimethylcyclohexyl Examples include alicyclic polyamines such as liamine; diamines with a norbornane skeleton such as norbornanediamine (NBDA, manufactured by Mitsui Chemicals, Inc.); polyamidoamines having an amino group at the molecular terminus of the polyamide; and 2,5-dimethyl-2,5-hexamethylenediamine, mensendiamine, 1,4-bis(2-amino-2-methylpropyl)piperazine, and Jeffermin D230 and Jeffermin D400 manufactured by Sun Techno Chemical Co., Ltd., which have a polypropylene glycol (PPG) skeleton.

[0029] For the reasons that the effects of the present invention are superior, aromatic polyamines are preferred, and dimethylthiotoluenediamine is more preferred.

[0030] <Molecular weight> The number-average molecular weight (Mn) of the polyamine is preferably 50 to 2,000, and more preferably 100 to 1,000, for better performance of the present invention.

[0031] [Isocyanate group / active hydrogen group] The specific oligomers are polymerized in a ratio of isocyanate groups to active hydrogen groups (hereinafter also referred to as "isocyanate group / active hydrogen group") of 0.3 to 1.0. Here, the active hydrogen group refers to the hydroxyl group of the specific diene polymer mentioned above, and the amino group of the polyamine mentioned above. The isocyanate group refers to the isocyanate group of the polyisocyanate mentioned above. The reason for limiting the isocyanate group / active hydrogen group ratio to 1.0 or less is to ensure that specific oligomers have very few isocyanate groups. If isocyanates are present, they may deactivate the vulcanization accelerator, potentially preventing sufficient vulcanization.

[0032] The isocyanate group / active hydrogen group ratio is preferably 0.5 to 0.8, and more preferably 0.6 to 0.7, for better effects of the present invention.

[0033] [Weight average molecular weight] The weight-average molecular weight (Mw) of the specific oligomers ranges from 3,000 to 50,000. Because the Mw of the specific oligomers falls within this range, they are considered to be uniformly dispersed within the diene-based rubber.

[0034] The Mw of the specific oligomer is preferably 10,000 to 45,000, and more preferably 20,000 to 40,000, for the sake of superior effects of the present invention.

[0035] [Urea bond / urethane bond] The specified oligomer has urethane bonds and urea bonds, and the molar ratio of urea bonds to urethane bonds (hereinafter also referred to as "urea bond / urethane bond") is 0.1 to 3.0. As described above, it is thought that urethane bonds and urea bonds form aggregates through hydrogen bonding. Because the urea bond / urethane bond ratio of the specified oligomer is within the above range, it is considered to have an excellent balance between mechanical properties and dispersibility in diene-based rubbers. More specifically, it is thought that aggregates are formed as the urea bond / urethane bond ratio increases, while dispersibility decreases if the urea bond / urethane bond ratio is too large.

[0036] The urea bond / urethane bond is preferably 0.2 to 2.7, more preferably 0.3 to 2.3, even more preferably 0.4 to 2.0, and particularly preferably 0.5 to 1.0, for reasons that the effects of the present invention are superior.

[0037] [Hard segment quantity] The total proportion of the portion derived from the polyisocyanate and the portion derived from the polyamine mentioned above, relative to the entire specific oligomer (hereinafter also referred to as the "hard segment amount"), is preferably 3 to 60% by mass, more preferably 6 to 40% by mass, even more preferably 8 to 30% by mass, particularly preferably 10 to 25% by mass, and most preferably 12 to 20% by mass, for reasons that the effects of the present invention are superior.

[0038] The proportion of the portion derived from the polyisocyanate described above to the total specific oligomer is preferably 2 to 50% by mass, more preferably 4 to 40% by mass, even more preferably 6 to 30% by mass, and particularly preferably 8 to 20% by mass, for reasons that the effects of the present invention are superior.

[0039] The proportion of the portion derived from the polyamine described above to the total specific oligomer is preferably 1 to 30% by mass, more preferably 2 to 20% by mass, and even more preferably 3 to 10% by mass, for the reasons that the effects of the present invention are superior.

[0040] [Soft segment quantity] The proportion of the portion derived from the above-mentioned specific diene polymer relative to the entire specific oligomer (hereinafter also referred to as the "soft segment amount") is preferably 40 to 97% by mass, more preferably 60 to 94% by mass, even more preferably 70 to 92% by mass, particularly preferably 75 to 90% by mass, and most preferably 80 to 88% by mass, for reasons that the effects of the present invention are superior.

[0041] [Optional ingredients] The composition of the present invention may optionally contain other components (optional components) as long as they do not impair its effects or purpose. Examples of the optional components mentioned above include fillers, silane coupling agents, terpene resins (e.g., aromatically modified terpene resins), thermally expandable microcapsules, zinc oxide (zinc oxide), stearic acid, antioxidants, waxes, processing aids, oils, liquid polymers, thermosetting resins, vulcanizing agents (e.g., sulfur), and various other additives commonly used in rubber compositions.

[0042] [Filler] The composition of the present invention preferably contains a filler because it provides superior effects. The composition of the present invention preferably contains at least one filler selected from the group consisting of carbon black and white fillers, and more preferably contains both carbon black and white fillers (particularly silica), for better effects of the present invention.

[0043] <Carbon Black> The carbon black mentioned above is not particularly limited, and various grades such as SAF-HS, SAF, ISAF-HS, ISAF, ISAF-LS, IISAF-HS, HAF-HS, HAF, HAF-LS, FEF, GPF, and SRF can be used. The nitrogen adsorption specific surface area (N2SA) of the carbon black described above is not particularly limited, but for the reason that the effects of the present invention are superior, it is 50 to 200 m². 2 It is preferable that the value be / g, and 70-150m 2 It is more preferable that it be / g. Here, the nitrogen adsorption specific surface area (N2SA) is the value obtained by measuring the amount of nitrogen adsorbed onto the carbon black surface according to JIS K6217-2:2001 "Part 2: Method for determining specific surface area - Nitrogen adsorption method - Single point method".

[0044] <White filler> The above-mentioned white filler is not particularly limited, but examples include silica, calcium carbonate, magnesium carbonate, talc, clay, alumina, aluminum hydroxide, titanium dioxide, calcium sulfate, etc. Among these, silica is preferred because it exhibits superior effects compared to the present invention.

[0045] The silica mentioned above is not particularly limited, but examples include wet silica (hydrated silica), dry silica (anhydrous silica), calcium silicate, and aluminum silicate. Among these, wet silica is preferred because it provides superior effects in the present invention.

[0046] The specific surface area of ​​the above silica for cetyltrimethylammonium bromide (CTAB) adsorption is not particularly limited, but for superior effects of the present invention, 100 to 400 m² is preferred. 2 It is preferable that the amount be / g, and 150-300m 2 It is more preferable that it be / g. Here, the CTAB adsorption specific surface area is the value obtained by measuring the amount of CTAB adsorbed onto the silica surface according to JIS K6217-3:2001 "Part 3: Method for determining specific surface area - CTAB adsorption method".

[0047] <Content> In the composition of the present invention, the content of the filler is preferably 1 to 200 parts by mass, and more preferably 10 to 100 parts by mass, per 100 parts by mass of the diene rubber described above, for the reason that the effects of the present invention are superior.

[0048] When the composition of the present invention contains carbon black, the carbon black content is preferably 0.1 to 100 parts by mass, and more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the diene rubber described above, for the reason that the effects of the present invention are superior.

[0049] When the composition of the present invention contains a white filler (particularly silica), the amount of the white filler is preferably 1 to 100 parts by mass, and more preferably 30 to 70 parts by mass, per 100 parts by mass of the diene rubber described above, for the reason that the effects of the present invention are superior.

[0050] [Silane coupling agent] The composition of the present invention preferably contains a silane coupling agent for superior effects. The silane coupling agent is not particularly limited as long as it is a silane compound having a hydrolyzable group and an organic functional group. The above hydrolyzable group is not particularly limited, but examples include alkoxy groups, phenoxy groups, carboxyl groups, and alkenyloxy groups. Among these, an alkoxy group is preferred because it provides superior effects of the present invention. When the hydrolyzable group is an alkoxy group, the number of carbon atoms in the alkoxy group is preferably 1 to 16, and more preferably 1 to 4, for superior effects of the present invention. Examples of alkoxy groups with 1 to 4 carbon atoms include methoxy groups, ethoxy groups, and propoxy groups.

[0051] The above organic functional groups are not particularly limited, but are preferably groups that can form chemical bonds with organic compounds, for example, epoxy groups, vinyl groups, acryloyl groups, methacryloyl groups, amino groups, sulfide groups (especially polysulfide groups (-S) nExamples include (n is an integer of 2 or more), mercapto groups, blocked mercapto groups (protected mercapto groups) (e.g., octanoylthio groups), and among these, sulfide groups (especially disulfide groups, tetrasulfide groups), mercapto groups, and blocked mercapto groups are preferred because they provide superior effects for the present invention. Silane coupling agents may be used individually or in combination of two or more types.

[0052] The silane coupling agent described above is preferably a sulfur-containing silane coupling agent because it provides superior effects in the present invention.

[0053] Specific examples of the silane coupling agents mentioned above include bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)disulfide, mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl-tetrasulfide, trimethoxysilylpropyl-mercaptobenzothiazoletetrasulfide, triethoxysilylpropyl-methacrylate-monosulfide, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyl-tetrasulfide, and 3-octanoylthio-1-propyltriethoxysilane. One of these may be used alone, or two or more may be used in combination.

[0054] In the composition of the present invention, the content of the silane coupling agent is not particularly limited, but for reasons that the effects of the present invention are superior, it is preferably 2 to 20% by mass, and more preferably 5 to 15% by mass, relative to the content of the filler (especially silica) mentioned above.

[0055] 〔oil〕 The composition of the present invention preferably contains oil because it provides superior effects.

[0056] In the composition of the present invention, the amount of the above-mentioned oil is preferably 1 to 100 parts by mass, and more preferably 2 to 10 parts by mass, per 100 parts by mass of the diene rubber, for the reason that the effects of the present invention are superior.

[0057] In the composition of the present invention, the total content of the above-mentioned specific oligomer and the above-mentioned oil is preferably 1 to 100 parts by mass, more preferably 2 to 20 parts by mass, and even more preferably 5 to 10 parts by mass, per 100 parts by mass of the above-mentioned diene rubber, for the reason that the effects of the present invention are superior.

[0058] [Method for manufacturing rubber composition] The method for producing the composition of the present invention is not particularly limited, and specific examples include, for example, a method of kneading each of the above-mentioned components using known methods and equipment (e.g., Banbury mixer, kneader, roll, etc.). If the composition of the present invention contains sulfur or a vulcanization accelerator, it is preferable to first mix the components other than sulfur and the vulcanization accelerator at a high temperature (preferably 100 to 155°C), cool them, and then mix in the sulfur or vulcanization accelerator. Furthermore, the compositions of the present invention can be vulcanized or crosslinked under conventionally known vulcanization or crosslinking conditions.

[0059] [Application] The composition of the present invention is suitably used as a rubber material. For example, it is suitably used in tires (especially pneumatic tires), conveyor belts, hoses, vibration dampers, rubber rolls, railway vehicle hoods, etc. Among these, it is particularly suitably used in tires (especially treads).

[0060] [2] Tires The tire of the present invention is a tire manufactured using the composition of the present invention described above. The tire of the present invention is preferably a pneumatic tire and can be filled with air, an inert gas such as nitrogen, and other gases. In particular, it is preferable that the composition of the present invention is used (placed) in the tire tread (cap tread). Figure 1 shows a schematic partial cross-sectional view of a tire representing an example of an embodiment of the tire of the present invention, but the tire of the present invention is not limited to the embodiment shown in Figure 1.

[0061] In Figure 1, reference numeral 1 represents the bead portion, reference numeral 2 represents the sidewall portion, and reference numeral 3 represents the tire tread portion. Furthermore, a carcass layer 4 with embedded fiber cords is installed between the pair of left and right bead sections 1, and the ends of this carcass layer 4 are folded back and wrapped around the bead core 5 and bead filler 6 from the inside to the outside of the tire. Furthermore, in the tire tread section 3, a belt layer 7 is arranged around the entire circumference of the tire, on the outside of the carcass layer 4. Furthermore, a rim cushion 8 is positioned in the bead portion 1 where it contacts the rim. The tire tread portion 3 is formed using the composition of the present invention as described above.

[0062] The tire of the present invention can be manufactured, for example, by conventionally known methods. In addition to ordinary air or air with adjusted oxygen partial pressure, inert gases such as nitrogen, argon, and helium can be used as the gas to fill the tire. [Examples]

[0063] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0064] [Synthesis of polyurethane oligomers 1-6 and comparative polyurethanes 1-3] Polyurethane oligomers 1-6 and comparative polyurethanes 1-3 were synthesized as follows. Polyurethane oligomers 1-6 fall under the category of specified oligomers as described above, while comparative polyurethanes 1-3 do not fall under the category of specified oligomers as described above.

[0065] [Polyurethane oligomer 1] 100.0 g of polyisoprene polyol (Poly ip, Mn: 2,500, manufactured by Idemitsu Kosan Co., Ltd.), 12.0 g of carbodiimide-modified MDI (Millionate MTL, manufactured by Tosoh Corporation), and 5.3 g of dimethylthiotoluenediamine (Heartcure 30, manufactured by Kumiai Chemical Co., Ltd.) were mixed and reacted under a nitrogen atmosphere with stirring at 80°C for 2 hours. The isocyanate group / active hydrogen group ratio was 0.63. An oligomer was obtained in this way. The obtained oligomer is also called polyurethane oligomer 1. Polyurethane oligomer 1 had a weight-average molecular weight of 36,856, a urea bond / urethane bond ratio of 0.6, and a hard segment content of 15% by mass.

[0066] [Polyurethane oligomer 2] 100.0 g of polybutadiene polyol (Poly bd R-15HT, Mn: 1,200, manufactured by Idemitsu Kosan Co., Ltd.), 26.1 g of carbodiimide-modified MDI (Millionate MTL, manufactured by Tosoh Corporation), and 11.6 g of dimethylthiotoluenediamine (HeartCure 30, manufactured by Kumiai Chemical Co., Ltd.) were mixed and reacted under a nitrogen atmosphere by stirring at 80°C for 2 hours. The isocyanate group / active hydrogen group ratio was 0.63. An oligomer was obtained in this way. The obtained oligomer is also called polyurethane oligomer 2. Polyurethane oligomer 2 had a weight-average molecular weight of 32,198, a urea bond / urethane bond ratio of 0.6, and a hard segment content of 27% by mass.

[0067] [Polyurethane oligomer 3] 100.0 g of polybutadiene polyol (Poly bd R-45HT, Mn: 2,800, manufactured by Idemitsu Kosan Co., Ltd.), 11.6 g of carbodiimide-modified MDI (Millionate MTL, manufactured by Tosoh Corporation), and 5.2 g of dimethylthiotoluenediamine (Heartcure 30, manufactured by Kumiai Chemical Co., Ltd.) were mixed and reacted under a nitrogen atmosphere by stirring at 80°C for 2 hours. The isocyanate group / active hydrogen group ratio was 0.63. An oligomer was obtained in this way. The obtained oligomer is also called polyurethane oligomer 3. Polyurethane oligomer 3 had a weight-average molecular weight of 41,443, a urea / urethane bond ratio of 0.6, and a hard segment content of 14% by mass. The same applies to subsequent entries.

[0068] [Polyurethane oligomer 4] 100.0 g of polyisoprene polyol (Poly ip, Mn: 2,500, manufactured by Idemitsu Kosan Co., Ltd.), 30.1 g of carbodiimide-modified MDI (Millionate MTL, manufactured by Tosoh Corporation), and 22.2 g of dimethylthiotoluenediamine (Heartcure 30, manufactured by Kumiai Chemical Co., Ltd.) were mixed and reacted under a nitrogen atmosphere by stirring at 80°C for 2 hours. The isocyanate group / active hydrogen group ratio was 0.71. An oligomer was obtained in this way. The obtained oligomer is also called polyurethane oligomer 4. Polyurethane oligomer 4 had a weight-average molecular weight of 13,367, a urea bond / urethane bond ratio of 2.5, and a hard segment content of 34% by mass.

[0069] [Polyurethane oligomer 5] 100.0 g of polyisoprene polyol (Poly ip, Mn: 2,500, manufactured by Idemitsu Kosan Co., Ltd.), 42.1 g of carbodiimide-modified MDI (Millionate MTL, manufactured by Tosoh Corporation), and 26.7 g of dimethylthiotoluenediamine (Heartcure 30, manufactured by Kumiai Chemical Co., Ltd.) were mixed and reacted under a nitrogen atmosphere by stirring at 80°C for 2 hours. The isocyanate group / active hydrogen group ratio was 0.88. An oligomer was obtained in this way. The obtained oligomer is also called polyurethane oligomer 5. Polyurethane oligomer 5 had a weight-average molecular weight of 15,262, a urea / urethane bond ratio of 3.0, and a hard segment content of 41% by mass.

[0070] [Polyurethane oligomer 6] 100.0 g of polyisoprene polyol (Poly ip, Mn: 2,500, manufactured by Idemitsu Kosan Co., Ltd.), 12.0 g of carbodiimide-modified MDI (Millionate MTL, manufactured by Tosoh Corporation), and 22.1 g of polymeric diamine (Elasmer 650P, manufactured by Kumiai Chemical Co., Ltd.) were mixed and reacted under a nitrogen atmosphere with stirring at 80°C for 2 hours. The isocyanate group / active hydrogen group ratio was 0.63. An oligomer was obtained in this way. The obtained oligomer is also called polyurethane oligomer 6. Polyurethane oligomer 6 had a weight-average molecular weight of 41,572, a urea bond / urethane bond ratio of 0.6, and a hard segment content of 25% by mass.

[0071] [Polyurethane oligomer 7] 100.0 g of polyisoprene polyol (Poly ip, Mn: 2,500, manufactured by Idemitsu Kosan Co., Ltd.), 9.6 g of carbodiimide-modified MDI (Millionate MTL, manufactured by Tosoh Corporation), and 2.7 g of dimethylthiotoluenediamine (Heartcure 30, manufactured by Kumiai Chemical Co., Ltd.) were mixed and reacted under a nitrogen atmosphere by stirring at 80°C for 2 hours. The isocyanate group / active hydrogen group ratio was 0.62. An oligomer was obtained in this way. The obtained oligomer is also called polyurethane oligomer 7. Polyurethane oligomer 7 had a weight-average molecular weight of 43,369, a urea bond / urethane bond ratio of 0.3, and a hard segment content of 11% by mass.

[0072] [Polyurethane oligomer 8] 100.0 g of polyisoprene polyol (Poly ip, Mn: 2,500, manufactured by Idemitsu Kosan Co., Ltd.), 15.0 g of carbodiimide-modified MDI (Millionate MTL, manufactured by Tosoh Corporation), and 8.9 g of dimethylthiotoluenediamine (Heartcure 30, manufactured by Kumiai Chemical Co., Ltd.) were mixed and reacted under a nitrogen atmosphere with stirring at 80°C for 2 hours. The isocyanate group / active hydrogen group ratio was 0.63. An oligomer was obtained in this way. The obtained oligomer is also called polyurethane oligomer 8. Polyurethane oligomer 8 had a weight-average molecular weight of 24,754, a urea bond / urethane bond ratio of 1.0, and a hard segment content of 19% by mass.

[0073] [Comparative Polyurethane 1] 100.0 g of polybutadiene polyol (Poly bd R-45HT, Mn: 2,800, manufactured by Idemitsu Kosan Co., Ltd.), 11.6 g of carbodiimide-modified MDI (Millionate MTL, manufactured by Tosoh Corporation), and 3.5 g of 1,8-octanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) were mixed and reacted under a nitrogen atmosphere with stirring at 80°C for 2 hours. The isocyanate group / active hydrogen group ratio was 0.63. An oligomer was obtained in this way. The obtained oligomer is also called comparative polyurethane 1. Comparative polyurethane 1 had a weight-average molecular weight of 26,906, 0 urea / urethane bonds (i.e., it had urethane bonds but no urea bonds), and a hard segment content of 12% by mass.

[0074] [Comparative Polyurethane 2] 100.0 g of polybutadiene polyol (Poly bd R-45HT, Mn: 2,800, manufactured by Idemitsu Kosan Co., Ltd.) and 17.8 g of 4,4'-diphenylmethane diisocyanate (Millionate MT, manufactured by Tosoh Corporation) were mixed and reacted under a nitrogen atmosphere by stirring at 70°C for 2 hours. 100.0 g of the resulting urethane prepolymer was mixed with 6.5 g of dimethylthiotoluenediamine (Heartcure 30, manufactured by Kumiai Chemical Co., Ltd.) and reacted under a nitrogen atmosphere by stirring for 5 minutes. The isocyanate group / active hydrogen group ratio was 1.00. An oligomer was obtained in this manner. The obtained oligomer is also called comparative polyurethane 2. Comparative polyurethane 2 had a weight-average molecular weight of 102,451, a urea bond / urethane bond ratio of 1.0, and a hard segment content of 20% by mass.

[0075] [Comparative Polyurethane 3] 100.0 g of polybutadiene polyol (Poly bd R-45HT, Mn: 2,800, manufactured by Idemitsu Kosan Co., Ltd.), 29.0 g of carbodiimide-modified MDI (Millionate MTL, manufactured by Tosoh Corporation), and 5.2 g of dimethylthiotoluenediamine (HeartCure 30, manufactured by Kumiai Chemical Co., Ltd.) were mixed and reacted under a nitrogen atmosphere by stirring at 80°C for 2 hours. The isocyanate group / active hydrogen group ratio was 1.56. An oligomer was obtained in this way. The obtained oligomer is also called comparative polyurethane 3. Comparative polyurethane 3 had a weight-average molecular weight of 21,736, a urea bond / urethane bond ratio of 0.6, and a hard segment content of 25% by mass.

[0076] [Preparation of rubber composition] The components shown in Table 1 below were blended in the proportions (parts by mass) shown in the table. Specifically, the components excluding sulfur and vulcanization accelerator were first kneaded in a 1.7-liter sealed mixer for 5 minutes, and released when the temperature reached 150°C to obtain a masterbatch. Next, sulfur and vulcanization accelerator were kneaded into the obtained masterbatch in an open roll to obtain a rubber composition.

[0077] [evaluation] The obtained rubber compositions were evaluated as follows.

[0078] [Breaking strength and elongation at breaking] The obtained rubber composition was vulcanized at 170°C for 15 minutes using a mold of a predetermined shape (internal dimensions: length 150 mm, width 150 mm, thickness 2 mm) to produce a vulcanized rubber sheet. For the obtained vulcanized rubber sheet, a JIS No. 3 dumbbell-shaped test specimen (2 mm thick) was punched out in accordance with JIS K6251:2017, and the breaking strength and breaking elongation were measured under conditions of a temperature of 23°C and a tensile speed of 500 mm / min. The results are shown in Table 1. The results are expressed as an index with standard example 1 set to 100. A higher index indicates superior breaking strength or elongation at breaking.

[0079] [Wet performance and fuel efficiency] The obtained rubber composition was vulcanized at 170°C for 15 minutes using a mold of a predetermined shape (internal dimensions: length 150 mm, width 150 mm, thickness 2 mm) to produce a vulcanized rubber sheet. The tanδ of the obtained vulcanized rubber sheets was measured using a viscoelastic spectrometer (manufactured by Toyo Seiki Seisakusho Co., Ltd.) in accordance with JIS K6394:2007, at a tensile deformation strain of 10% ± 2%, a frequency of 20 Hz, and temperatures of 0°C and 60°C. Wet performance was evaluated from the tanδ at 0°C, and fuel efficiency was evaluated from the tanδ at 60°C. Wet performance is shown in Table 1 as an index with the value of Standard Example 1 set to 100. A higher index indicates better wet performance. Fuel efficiency is shown in Table 1 as an index, with the value of Standard Example 1 set to 100, using the reciprocal of the measured value. A higher index indicates better fuel efficiency.

[0080] [Table 1]

[0081] The details of each component shown in Table 1 are as follows. • SBR: Styrene-butadiene rubber, manufactured by Nippon Zeon Corporation (Tg (glass transition temperature): -51℃, Mw: 450,000) • Silica: Rhodia Zeosil 1165MP • Carbon Black: Tokai Carbon Co., Ltd. Seast 6 • Polyurethane oligomers 1-8: Polyurethane oligomers 1-8 synthesized as described above. • Comparative polyurethane 1-3: Comparative polyurethane 1-3 synthesized as described above. • Oil 1: Showa Shell Oil Co., Ltd. Extract No. 4 S • Silane coupling agent: Bis-(3-triethoxysilylpropyl)tetrasulfide, manufactured by Evonik, Si69 • Zinc oxide: Three types of zinc oxide manufactured by Seido Chemical Industry Co., Ltd. • Stearic acid: NOF Corporation's Bead Stearic Acid YR • Anti-aging agent: Flexis Santoflex 6PPD • Sulfur: Finely powdered sulfur containing Kinka oil, manufactured by Tsurumi Chemical Industries Co., Ltd. • Vulcanization accelerator 1: Noxellar CZ-G manufactured by Ouchi Shinko Chemical Industry Co., Ltd. • Vulcanization accelerator 2: Soccinol DG manufactured by Sumitomo Chemical Co., Ltd.

[0082] In Table 1, weight-average molecular weight, urea bond / urethane bond, hard segment amount, and isocyanate group / active hydrogen group represent the weight-average molecular weight, urea bond / urethane bond, hard segment amount, and isocyanate group / active hydrogen group, respectively, of polyurethane oligomers 1-6 or comparative polyurethanes 1-3 used in each example.

[0083] As can be seen from Table 1, Examples 1 to 9, which contained 100 parts by mass of diene rubber and 1 to 60 parts by mass of a specific oligomer, showed excellent breaking strength, breaking elongation, wet performance, and low fuel consumption performance.

[0084] A comparison of Examples 1, 4, 5, 7, and 8 (comparing embodiments where the content of a specific oligomer is 5 parts by mass per 100 parts by mass of diene rubber, the specific diene polymer used to produce the specific oligomer is polyisoprene polyol, and the polyamine used to produce the specific oligomer is dimethylthiotoluenediamine) showed that Examples 1, 4, and 7-8, with a hard segment content of 6-40% by mass, exhibited superior elongation at break and fuel efficiency. In particular, Examples 1 and 7-8, with a urea bond / urethane bond ratio of 0.1-2.0, showed even superior fuel efficiency. Among these, Examples 1 and 7, with a urea bond / urethane bond ratio of 0.2 or more and less than 1.0, showed even superior elongation at break and fuel efficiency. Among these, Example 1, with a urea bond / urethane bond ratio of 0.4-0.8, showed even superior tensile strength, wet performance, and fuel efficiency. Furthermore, a comparison between Example 1 and Example 9 (a comparison of embodiments that differ only in the content of the specific oligomer per 100 parts by mass of diene rubber) showed that Example 1, in which the content of the specific oligomer per 100 parts by mass of diene rubber was 3 to 20 parts by mass, exhibited superior elongation at break and low fuel consumption performance.

[0085] On the other hand, Standard Example 1, which did not contain the specific oligomer, exhibited insufficient tensile strength, elongation at break, and wet performance. Furthermore, Comparative Example 1, which contained comparative polyurethane 1 instead of the specific oligomer, exhibited insufficient tensile strength, wet performance, and fuel efficiency. Furthermore, Comparative Example 2, which contained comparative polyurethane 2 instead of the specific oligomer, exhibited insufficient tensile strength, elongation at break, wet performance, and fuel efficiency. Furthermore, Comparative Example 2, which contained comparative polyurethane 2 instead of the specific oligomer, exhibited insufficient tensile strength and fuel efficiency. [Explanation of Symbols]

[0086] 1. Bead section 2 Sidewall section 3. Tire tread section 4. Carcass layer 5 Bead core 6. Bead Filler 7 Belt layer 8 Rim Cushion

Claims

1. It contains 100 parts by mass of diene rubber and 1 to 60 parts by mass of polyurethane oligomer. The aforementioned polyurethane oligomer This is a polymer obtained by polymerizing a diene polymer having a hydroxyl group, a polyisocyanate, and a polyamine in a ratio such that the molar ratio of isocyanate groups to active hydrogen groups is 0.3 to 1.

0. The weight-average molecular weight is 3,000 to 50,000. A rubber composition having urethane bonds and urea bonds, wherein the molar ratio of the urea bonds to the urethane bonds is 0.1 to 3.

0.

2. The rubber composition according to claim 1, wherein the total proportion of the portion derived from the polyisocyanate and the portion derived from the polyamine to the entire polyurethane oligomer is 6 to 40% by mass.

3. The rubber composition according to claim 1, wherein the diene polymer having a hydroxyl group comprises at least one selected from the group consisting of polybutadiene polyol, hydrogenated polybutadiene polyol, and polyisoprene polyol.

4. The rubber composition according to claim 1, further comprising 1 to 100 parts by mass of at least one filler selected from the group consisting of carbon black and white fillers.

5. The rubber composition according to claim 1, wherein the number-average molecular weight of the polyamine is 50 to 500.

6. Furthermore, the rubber composition according to claim 1 contains 30 to 100 parts by mass of silica as a white filler.

7. A tire manufactured using the rubber composition described in any one of claims 1 to 6.

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