JP2015129297A - Rubber composition and tire using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition capable of improving dry performance, wet performance, and on-ice performance of a tire, and to provide a pneumatic tire having improved run-flat durability and ride quality.SOLUTION: Provided is a rubber composition for a tire, comprising: a rubber component containing an aromatic vinyl compound-conjugated diene compound copolymer, a conjugated diene compound polymer, or a natural rubber as a main component; a cyclic molecule; a linear molecule or a molecule having one branch point, clathrating the cyclic molecules in a skewered state; and a polyrotaxane where the linear molecule or the molecule having one branch point has blocking groups disposed at molecular terminals, preventing detachment of the cyclic molecules, or a polyrotaxane having the polyrotaxane crosslinked via a cyclic molecule. The polyrotaxane or the crosslinked polyrotaxane is contained in an amount of 0.1 to 20 pts.mass relative to 100 pts.mass of the rubber composition. Also provided is a pneumatic tire.

Description

  The present invention relates to a rubber composition and a tire using the rubber composition, and in particular, a tire rubber composition capable of improving both the dry performance, wet performance and on-ice performance of the tire, run flat durability and ride comfort. The present invention relates to an improved pneumatic tire.

In general, for example, in a studless tire that is a tire with improved winter performance, the low temperature is a temperature during running on ice, and a temperature of about −20 ° C. to 0 ° C. is considered as a representative example. When the dynamic storage elastic modulus (G ′) of the tread of the tire increases, the following contact with the road surface of the tire becomes insufficient, and the true contact area decreases, and the adhesion action between the tread and the road surface decreases. Since the braking performance is lowered, it is preferable to lower the dynamic storage elastic modulus of the tread at a low temperature. In addition, it is known that the strain caused by slippage between the tread and the road surface when traveling on such an icy road surface is generally very small, and the dynamic storage elastic modulus in a micro strain region below 1% of the tread is shown. It is particularly preferable to reduce it.

There is also a need to improve performance (dry performance) when using a studless tire on a road surface other than an icing road surface, that is, a dry road surface. Here, in developing a rubber composition for a tread having improved tire dry performance, in general, the loss tangent (tan δ (60 ° C.)) when sine wave deformation is applied in the vicinity of 60 ° C. is increased, and the temperature increases from 0 ° C. It is generally effective to increase the dynamic storage elastic modulus that can be placed under large deformation in a high temperature range. Specifically, when tan δ is high near 60 ° C. and large deformation of several percent or more is given. By using a rubber composition with increased dynamic storage modulus for the tread, the friction coefficient (μ) on the dry road surface of the tire is increased and the tread pattern element is prevented from excessive deformation to ensure a true contact area. Therefore, the dry performance can be improved. Even in a normal tire, by reducing the elastic modulus when wet (0 ° C.) and increasing G ′ at 60 ° C., it is possible to achieve both wet brake properties and dry properties. In other words, it is desired to use a rubber composition having a low storage elastic modulus at low temperature and low strain and an increased storage elastic modulus at high temperature and large strain as a tread material.
In order to improve winter performance, in addition to controlling the viscoelastic properties of the rubber composition described above, the road surface melts due to friction between the tread and the frozen road surface during braking and acceleration on the frozen road surface. It is a fact known to those skilled in the art that the removal of the generated water is effective. For that purpose, it is necessary to arrange bubbles such as foaming bubbles on the tread surface, and to improve the effect of a specific shape. A technique for arranging cylindrical bubbles is known (see, for example, Patent Document 2001-233993A). Furthermore, in order to pursue the scratching effect due to the minute protrusions in the above-mentioned situation, a technique is also known in which a resin component containing appropriate hardness particles is arranged on the tread surface (for example, “Japanese Patent Application No. 9 -533355 "(WO 97/34776). A technology that achieves the viscoelastic properties as described above without offsetting the effects of the known winter performance improvement technology due to such moisture removal and scratching effect is particularly desired.

On the other hand, conventionally, as a technique for increasing tan δ of a rubber composition, a technique of blending a C ₉ aromatic resin having a high glass transition point (Tg) into a rubber composition (see JP-A-5-9338). In addition, a technique for blending a liquid styrene-butadiene copolymer having a weight average molecular weight of tens of thousands into a rubber composition (see JP-A-61-203145) is known.

  Conventionally, in the pneumatic tire, as a technology to keep the vehicle behavior safely even when the internal pressure is lost due to puncture, etc., in order to improve the rigidity of the sidewall part, it is applied to the innermost side of the carcass of the sidewall part. There is a so-called side-reinforced run-flat tire in which a side reinforcing layer made of a rubber composition alone or a composite of a rubber composition and fibers is disposed. However, in traveling in a state where the internal pressure of the tire (hereinafter referred to as internal pressure) is reduced due to tire puncture or the like, the deformation of the side reinforcing layer increases as the deformation of the sidewall portion of the tire increases. The side reinforcing layer generates heat and may reach a high temperature of 200 ° C. or higher in some cases. In such a state, the side reinforcing layer may exceed its fracture limit, and the tire may not be able to travel a sufficient distance with no internal pressure.

  As a means for increasing the time to reach such a situation, there is a means for increasing the volume of the side reinforcing layer, for example, by increasing the maximum thickness of the side reinforcing layer. Problems such as deterioration of ride comfort, weight increase and noise increase occur. Further, there are means for increasing the maximum thickness of the bead filler disposed on the outer side in the tire radial direction of the bead core. However, in this case as well, problems such as deterioration in riding comfort, increase in weight, and increase in noise occur.

  On the other hand, if the volume of the side reinforcement layer and the bead filler is reduced in order to avoid deterioration in ride comfort, the sidewall portion cannot fully support the load applied to the tire during running without internal pressure, and the sidewall portion is not deformed. It becomes very large and the heat generation in the sidewall portion proceeds excessively. As a result, the tire becomes unable to run early.

  In addition, in order to avoid deterioration in ride comfort, the composition of the rubber composition used for the side reinforcing layer and the bead filler is changed, and even when the elastic modulus of the rubber composition is lowered, the side wall portion is run-running. The load applied to the tire cannot be supported, the deformation of the sidewall portion becomes extremely large, the heat generation of the sidewall portion proceeds excessively, and as a result, the tire becomes unable to run early. In order to satisfy the tire characteristics as described above, it can behave softly at the time of minute deformation at a temperature of about room temperature-60C, which is a problem in normal driving, and can behave hard at the time of non-internal pressure driving that causes a large strain at a higher temperature. A rubber composition that can be used as a side reinforcing rubber has been desired.

  In JP-A-2002-79803, the side reinforcing layer and the bead filler have a vinyl bond amount in the conjugated diene unit of 25% or more, a weight average molecular weight (Mw) of 200,000 to 900,000, and a weight average molecular weight. A rubber composition comprising a conjugated diene polymer having a molecular weight distribution (Mw / Mn) represented by a ratio of number average molecular weight (Mn) of 1 to 4 in a rubber component of 50% by weight or more was used. Tires are described.

However, in order to increase tan δ of the rubber composition, a C ₉ aromatic resin having a high glass transition point (Tg) or a liquid styrene-butadiene copolymer (hereinafter also referred to as liquid SBR) having a molecular weight of tens of thousands. When blended with a rubber composition, the dynamic storage modulus increases from −20 ° C. to around 0 ° C., so that a studless tire and a normal tire to which such a rubber composition is applied to a tread have braking and driving performance on ice. Is insufficient. As mentioned above, there is also a proposal to arrange bubbles such as foaming bubbles or molten foams of organic short fibers on the tread surface, but the strain dependency and temperature dependency of the elastic modulus are not sufficiently improved, and dry performance and There was much room for improvement in balancing the performance on ice.

  Further, the tire described in JP-A-2002-79803 has room for improvement in tire durability and ride comfort during run-flat running.

  Therefore, an object of the present invention is to provide a rubber composition capable of improving the dry performance and on-ice performance of a tire, and further the wear performance. Another object of the present invention is to provide a tire excellent in dry performance, on-ice performance and wear performance, particularly a tire with improved winter performance, using such a rubber composition in a tread.

Another object of the present invention is to provide a pneumatic tire with improved tire durability during run-flat running (hereinafter referred to as run-flat durability) and riding comfort.
The properties desired for the rubber composition common to the above-mentioned two purposes of the present invention are the properties of low storage modulus at low strain and high storage modulus at high strain, low storage modulus at low temperature, and storage at high temperature. The two points are the characteristics that increase the elastic modulus, but the former is particularly important.

  As a result of intensive studies to achieve the above object, the present inventors have found that polyrotaxane is added to a rubber component mainly composed of an aromatic vinyl compound-conjugated diene compound copolymer, a conjugated diene compound polymer, or natural rubber. Or it discovered that dry performance, wet performance, performance on ice, and wear performance improved by mix | blending a bridge | crosslinking polyrotaxane.

  In addition, a pneumatic tire using the rubber composition containing the polyrotaxane or the crosslinked polyrotaxane as at least one of the side reinforcing layer and the bead filler has good riding comfort during normal running and improved durability during run-flat running. I found out.

That is, the rubber composition of the present invention comprises an aromatic vinyl compound-conjugated diene compound copolymer, a conjugated diene compound polymer, or a rubber component mainly composed of natural rubber;
A cyclic molecule, a linear molecule that includes the cyclic molecule in a skewered manner, or a molecule having one branch point, and a terminal molecule of the linear molecule or molecule having one branch point. A polyrotaxane having a blocking group for preventing separation, or a crosslinked polyrotaxane in which the polyrotaxane is crosslinked via the cyclic molecule,
The polyrotaxane or the crosslinked polyrotaxane is contained in an amount of 0.1 to 20 parts by mass with respect to 100 parts by mass of the rubber component.

  In a preferred example of the rubber composition of the present invention, the aromatic vinyl compound is styrene, and the conjugated diene compound is isoprene or butadiene.

In another preferred embodiment of the rubber composition of the present invention, the aromatic vinyl compound-conjugated diene compound copolymer, or the conjugated diene compound polymer, or the rubber component mainly composed of natural rubber is natural rubber and / or The main component is at least one selected from polyisoprene rubber, polybutadiene rubber, and styrene-butadiene copolymer.
More preferably, the aromatic vinyl compound-conjugated diene compound copolymer, the conjugated diene compound polymer, or the rubber component mainly composed of natural rubber comprises natural rubber and / or polyisoprene rubber and polybutadiene rubber. It is characterized by being a main component.

In another preferred embodiment of the rubber composition of the present invention, the polyrotaxane linear molecule or the molecule having one branch point has an affinity for the rubber component as a matrix.
In another preferred embodiment of the rubber composition of the present invention, the polyrotaxane linear molecule or the molecule having one branch point is hydrophobic. Here, “having affinity” means that the difference in SP value is 5 or less.

  In another preferred embodiment of the rubber composition of the present invention, the linear molecule or the molecule having one branch point is polycaprolactone, styrene-butadiene copolymer, isobutene-isoprene copolymer, polyisoprene, natural rubber. (NR), polyethylene glycol, polyisobutylene, polybutadiene, polypropylene glycol, polytetrahydrofuran, polydimethylsiloxane, polyethylene, polypropylene, and ethylene-polypropylene copolymer, or styrene, α- A polymer of an aromatic vinyl compound selected from the group consisting of methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene and 2,4,6-trimethylstyrene. Or a conjugated diene compound selected from the group consisting of 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene and 1,3-hexadiene Or a copolymer of an aromatic vinyl compound and a conjugated diene compound.

  In another preferred embodiment of the rubber composition of the present invention, the molecular weight of the linear molecule or the molecule having one branch point is 1,000 to 100,000.

  In another preferred embodiment of the rubber composition of the present invention, the cyclic molecule is selected from the group consisting of cyclodextrin, crown ether, benzocrown, dibenzocrown and dicyclohexanocrown.

  In another preferred embodiment of the rubber composition of the present invention, the cyclic molecule is a cyclodextrin.

  In another preferred embodiment of the rubber composition of the present invention, the cyclic molecule is α, β, or γ-cyclodextrin.

  In another preferred embodiment of the rubber composition of the present invention, the blocking group is larger than the diameter of the inner surface of the cyclic molecule. More preferably, the blocking group is selected from the group consisting of dinitrophenyl groups, adamantyl groups, trityl groups, fluoresceins and pyrenes.

  In another preferred embodiment of the rubber composition of the present invention, the diameter of the inner surface of the cyclic molecule is the maximum diameter of the portion intended for inclusion of the linear molecule or the molecule having one branch point, which is the guest molecule to be included. It is larger and not more than 3 times.

  In another preferred embodiment of the rubber composition of the present invention, the inclusion amount of the cyclic molecule is a maximum inclusion amount that is the maximum amount of inclusion of the linear molecule or a molecule having one branch point of the cyclic molecule. If it is 1, it is 0.001-0.6.

In another preferred embodiment of the rubber composition of the present invention, the crosslinking agent used for crosslinking of the cyclic molecules serving as the host part of the polyrotaxane is capable of linking the functional groups of the cyclic molecules by a chemical reaction. For example, when cyclodextrins are used as a cyclic molecule, the crosslinking agent is a compound having a plurality of functional groups in the molecule that can be bonded to alcoholic hydroxyl groups by reactions such as condensation or substitution. is necessary. These plural functional groups may be the same or different from each other. In particular, cyanuric chloride, a compound having two or more carboxylic anhydride groups in the molecule (for example, trimesoyl chloride, terephthaloyl chloride), epichlorohydrin, a compound having two or more active halogens in the molecule (for example, dibromobenzene) ), Glutaraldehyde, compounds having two or more isocyanate groups in the molecule (phenylene diisocyanate and partial condensates thereof (known as crude MDI, which is generally distributed as a polyurethane raw material), diisocyanate trilein (polyurethane) It is generally selected from the group consisting of 1,8-diisocyanate octane), divinylsulfone, 1,1′-carbonyldiimidazole, and alkoxysilane.
In the present invention, it is preferable to use a crosslinked polyrotaxane. However, instead of blending the crosslinked polyrotaxane into the rubber composition, the polyrotaxane can be crosslinked after blending into the rubber composition. The effect of the present invention can be achieved also by such an embodiment, and is within the scope of the present invention. In this case, when the polyrotaxane is blended in the rubber composition, or after blending and before the vulcanization reaction, the crosslinking agent is separately blended in the rubber composition, and then the crosslinking is simultaneously performed during the vulcanization reaction of the rubber composition. In addition, the rubber composition can be reacted with the polyrotaxane in the rubber composition by impregnation by a method such as application as a solution before or after vulcanization of the rubber composition, and further by heat treatment. Whichever method is used, it is preferable that the crosslinking agent is added before the rubber composition is vulcanized from the viewpoint of simultaneously achieving the crosslinking reaction between the polyrotaxanes and the vulcanization reaction of the rubber as the matrix. .

  In another preferred embodiment of the rubber composition of the present invention, the rubber component comprises natural rubber (NR), polyisoprene rubber (IR), polybutadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), acrylonitrile butadiene. It is selected from the group consisting of rubber (NBR), chloroprene rubber (CR) and butyl rubber (IIR).

  In another preferred embodiment of the rubber composition of the present invention, the rubber component has a glass transition temperature (Tg) of 0 ° C. or lower.

In another preferred embodiment of the rubber composition of the present invention, the rubber component is polybutadiene rubber (BR) having a vinyl content of 30% or less.
In another preferred embodiment of the rubber composition of the present invention, the rubber component comprises natural rubber (NR) and cis-1,4-polybutadiene rubber (BR).

  In another preferred embodiment of the rubber composition of the present invention, the rubber composition further comprises at least one filler selected from the group consisting of carbon black and white filler.

  The tire of the present invention is characterized by using the rubber composition in a tread.

The pneumatic tire of the present invention has a pair of bead portions and a pair of sidewall portions, and a tread portion connected to both sidewall portions, and extends in a toroidal shape between the pair of bead portions, A radial carcass that reinforces each of these parts, a bead filler that is disposed outside the bead core in the tire radial direction of each bead core, and a pair of side reinforcing layers that are disposed on the inner surface of the carcass in the sidewall part. In the pneumatic tire, as the rubber composition of the side reinforcing layer and / or bead filler,
Further, the rubber composition containing sulfur and a filler is used.

  Further, in the pneumatic tire of the present invention, the rubber composition is 0.1 to 20 parts by mass of the polyrotaxane or the crosslinked polyrotaxane and 2 parts by mass or more of the sulfur with respect to 100 parts by mass of the rubber component. It contains 10 to 100 parts by mass of the agent.

  Moreover, the pneumatic tire of the present invention is characterized in that it contains at least part of carbon black as the filler.

  ADVANTAGE OF THE INVENTION According to this invention, the rubber composition which can improve the dry performance, on-ice performance, and abrasion performance of a studless tire can be provided. Moreover, by using such a rubber composition for a tread, a studless tire excellent in dry performance, wet performance, performance on ice, and wear performance can be provided.

  In addition, according to the present invention, it is possible to provide a pneumatic tire that is excellent in ride comfort during normal travel, both during run flat travel and run flat durability.

It is sectional drawing which shows one embodiment of the pneumatic tire of this invention.

  The present invention is described in detail below. The rubber composition of the present invention comprises an aromatic vinyl compound-conjugated diene compound copolymer, a conjugated diene compound polymer, or a rubber component mainly composed of natural rubber, a cyclic molecule, and the cyclic molecule skewered. A polyrotaxane having a blocking molecule which is disposed at the end of the linear molecule or molecule having one branch point and which is included at the end of the linear molecule or molecule having one branch point to prevent the elimination of the cyclic molecule, or A crosslinked polyrotaxane obtained by crosslinking the polyrotaxane is included. The aromatic vinyl compound is preferably styrene, and the conjugated diene compound is preferably isoprene or butadiene. The aromatic vinyl compound-conjugated diene compound copolymer, conjugated diene compound polymer, or rubber component mainly composed of natural rubber is preferably composed mainly of natural rubber and / or polyisoprene rubber and polybutadiene rubber. Ingredients.

  The polyrotaxane used in the rubber composition of the present invention is a new type of gel that is not classified as either a physical gel or a chemical gel, that is, a “ringing gel or topological gel”. The polyrotaxane used here is a linear molecule that penetrates through the opening of a cyclic molecule (rotor) in a skewered manner with a linear molecule (axis: axis) or a molecule having one branch point. Alternatively, a blocking group is arranged at the end of a linear molecule or a molecule having one branch point so as to be included by a molecule having one branch point and not to leave the cyclic molecule.

  In addition, a plurality of such polyrotaxanes can be cross-linked to obtain a cross-linked polyrotaxane applicable to a tumbling gel. This bridged polyrotaxane is a pulley in which a linear molecule or a cyclic molecule penetrating through a molecule having one branch point can move along the linear molecule or a molecule having one branch point. It has viscoelasticity for the effect, and even if tension is applied, the tension can be evenly dispersed by this pulley effect, so that unlike conventional crosslinked polymers, cracks and scratches are extremely unlikely to occur. It has properties. Such a crosslinked polyrotaxane is described in, for example, Japanese Patent No. 3475252.

  That is, the cross-linked polyrotaxane is also referred to as a slide ring gel, in which an 8-shaped cross-linking point exists, and a polymer network is formed by the topological constraint. The 8-shaped bridge point has a shape similar to that of a pulley and is also called a pulley bridge point. A slide ring gel comprising a crosslinked polyrotaxane has the property that the crosslinking point moves freely to eliminate network non-uniformity. That is, when the slide ring gel is stretched, slip occurs at the cross-linking point, and the “pulley effect” of adjusting the length between the polymers so that the tension becomes uniform acts, so that the force is dispersed. Therefore, the slide ring gel is difficult to cut and has a characteristic that it stretches well with a small stress. On the other hand, when the strain of the slide ring gel exceeds a certain level, the blocking group acting as a stopper suppresses the above-described slip of the crosslinking point, the polymer chain starts to stretch completely, and the stress elongation curve rises rapidly. When the force is relaxed, the reverse process is followed inside the gel to return to the original state, so that a sliding ring gel such as a crosslinked polyrotaxane exhibits unique physical properties. That is, such a crosslinked polyrotaxane has a very low elastic modulus compared to a normal elastomer in a low strain state, and has a unique property of having a high elastic modulus close to that of a normal elastomer in a high strain state.

  In addition, when the polyrotaxane solution satisfies the balance of affinity between an appropriate swelling solvent such as water and the cyclic molecules, a so-called LCST-type sol-gel transition phenomenon is observed. It is known to have a unique property of high modulus at high temperatures. Such an effect is also expected in a gel of a crosslinked polyrotaxane.

  That is, when a rubber composition in which a cyclic molecule such as cyclodextrin acts as a pulley cross-linking point as described above is prepared, the cyclodextrin portion gathers due to the increased mobility of the molecular chain at high temperatures, The elastic modulus is improved by further forming pseudo-crosslinks by physical interaction. Theoretically, when one or more pulley cross-linking points exist in one polyrotaxane linear molecule or a molecule having one branch point, the effect is remarkably increased.

Due to the characteristics of the polyrotaxane or crosslinked polyrotaxane as described above, when a tire is produced using a rubber composition containing the polyrotaxane or crosslinked polyrotaxane as a tread, the dynamic storage elastic modulus (G ′) becomes low at low temperature and low strain. This improves the performance on ice. On the other hand, at high temperature and high strain, the dynamic storage elastic modulus (G ′) becomes high, and improvement in dry handling performance is achieved. As a result, a tire with improved winter performance and dry performance can be obtained.
Furthermore, due to the characteristics of the polyrotaxane or the crosslinked polyrotaxane as described above, when the crosslinked polyrotaxane is used as a side reinforcing rubber and / or bead filler of a side reinforcing type run-flat tire, the distortion is low and the elasticity is low during normal driving. It becomes highly elastic during high run-flat driving. Therefore, it is possible to achieve both excellent ride comfort during normal running and suppression of deflection during run-flat running. That is, since the cross-linked polyrotaxane has a pulley cross-linking point, in the low strain region, the cross-linking point is flexible and thus has low elasticity, while in the high strain region, it is fully elastic and high in elasticity. The effect that can be obtained can be obtained.

  Note that, even with non-crosslinked polyrotaxanes, physical crosslinking between cyclic molecules such as cyclodextrins due to the surrounding environment such as temperature can occur. Even if there is no polyrotaxane, the intended effect of the present invention can be obtained.

  Further, in typical polyrotaxanes and cross-linked polyrotaxanes, cyclodextrins are often used as cyclic molecules. However, since the cyclic molecules have a large number of highly hydrophilic hydroxyl groups, they are preferable for rubber components. The affinity for the less polar diene-based elastomer molecules used is generally low. On the other hand, when the polyrotaxane is completely compatible with the rubber component, it becomes difficult for different cyclic molecules including the same or different guest molecules to cause physical crosslinking, and thus the effect is lowered. In order to obtain the desired effect in the present invention, the polyrotaxane or the crosslinked polyrotaxane preferably has a domain size that is small enough not to impair the breaking strength of the rubber composition in the rubber composition. It is preferable that the molecules have a domain size such that the molecules physically cross-link and affect the elastic modulus. That is, the polyrotaxane or the crosslinked polyrotaxane is considered not to be molecularly compatible with each other in the rubber composition, and the desired effect can be enhanced by the presence of an appropriately sized island. From the above viewpoint, in the present invention, it is a preferred embodiment that the linear molecule constituting the polyrotaxane or the molecule having one branch point is hydrophobic. In addition, about the polyrotaxane whose linear molecule is hydrophobic, it describes in Unexamined-Japanese-Patent No. 2007-63398, for example.

  Furthermore, in the present invention, it is essential that the cross-linking agent used for cross-linking the cyclic molecules serving as the host part of the polyrotaxane is capable of linking the functional groups of the cyclic molecules by chemical reaction. When a class is used as a cyclic molecule, the cross-linking agent must be a compound having a plurality of functional groups in the molecule that can be bonded to the alcoholic hydroxyl group by a reaction such as condensation or substitution. These plural functional groups may be the same or different from each other. In particular, cyanuric chloride, a compound having two or more carboxylic anhydride groups in the molecule (for example, trimesoyl chloride, terephthaloyl chloride), epichlorohydrin, a compound having two or more active halogens in the molecule (for example, dibromobenzene) ), Glutaraldehyde, compounds having two or more isocyanate groups in the molecule (phenylene diisocyanate and partial condensates thereof (known as crude MDI, which is generally distributed as a polyurethane raw material), diisocyanate trilein (polyurethane) It is preferably selected from the group consisting of 1,8-diisocyanate octane), divinylsulfone, 1,1′-carbonyldiimidazole and alkoxysilanes, which are generally distributed as raw materials and known by the name of TDI). But to them Not intended to be constant.

  In the present invention, it is preferable to use a crosslinked polyrotaxane. However, instead of blending the crosslinked polyrotaxane into the rubber composition, the polyrotaxane can be crosslinked after blending into the rubber composition. The effect of the present invention can be achieved also by such an embodiment, and is within the scope of the present invention. In this case, when the polyrotaxane is blended in the rubber composition, or after blending and before the vulcanization reaction, the crosslinking agent is separately blended in the rubber composition, and then the crosslinking is simultaneously performed during the vulcanization reaction of the rubber composition. In addition, the rubber composition can be reacted with the polyrotaxane in the rubber composition by impregnation by a method such as application as a solution before or after vulcanization of the rubber composition, and further by heat treatment. Whichever method is used, it is preferable that the crosslinking agent is added before the rubber composition is vulcanized from the viewpoint of simultaneously achieving the crosslinking reaction between the polyrotaxanes and the vulcanization reaction of the rubber as the matrix. Yes. In this embodiment, it is preferable that the crosslinking agent has a certain degree of affinity with the rubber matrix. When impregnation is performed by coating, it is preferable that the crosslinking agent is soluble in an appropriate solvent having a high affinity for the rubber matrix. .

  The present invention is arranged at both ends of a cyclic molecule, a linear molecule that includes the cyclic molecule in a skewered manner, or a molecule that has one branch point, and the linear molecule or a molecule that has one branch point. It is the most remarkable feature that the rubber composition contains the polyrotaxane having a blocking group for preventing the elimination of the cyclic molecule or the crosslinked polyrotaxane. The compounding amount of the polyrotaxane or the crosslinked polyrotaxane is preferably 0.1 to 20 parts by mass with respect to 100 parts by mass of the rubber component. If the polyrotaxane or the crosslinked polyrotaxane is less than 0.1 parts by mass, the effects of the present invention cannot be achieved. If the polyrotaxane or the crosslinked polyrotaxane is less than 20 parts by mass, there is a possibility that the crosslinking point becomes excessive and the elongation at break (Eb) decreases. .

  Specific examples of linear molecules or molecules having one branch point that can be used in the present invention include polycaprolactone, natural rubber (NR), hydrophilic polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, and poly (meth). Acrylic acid, cellulose resin (carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, etc.), polyacrylamide, polyethylene oxide, polyethylene glycol, polyvinyl acetal resin, polyvinyl methyl ether, polyamine, polyethyleneimine, casein, gelatin, starch, etc. and / or Or copolymers thereof; hydrophobic polymers such as polyethylene, polypropylene, styrene-butadiene copolymers, isobutene-isoprene copolymers, and the like Copolymer resins with olefin monomers, polyolefin resins such as polyisoprene, polyester resins, polyvinyl chloride resins, polystyrene, polystyrene resins such as acrylonitrile-styrene copolymer resins, polymethyl methacrylate and ( (Meth) acrylic acid ester copolymers, acrylic resins such as acrylonitrile-methyl acrylate copolymer resins, polycarbonate resins, polyurethane resins, vinyl chloride-vinyl acetate copolymer resins, polyvinyl butyral resins, etc .; and derivatives or modified products thereof; Polymers of aromatic vinyl compounds such as styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene and 2,4,6-trimethylstyrene; Polymers of conjugated diene compounds such as 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene; and their aromatic vinyls Mention may be made of a copolymer of a compound and a conjugated diene compound.

  Of these, those having affinity for the conjugated diene rubber used as the rubber matrix of the present invention are preferable. Especially polycaprolactone, styrene-butadiene copolymer, polyisobutene, isobutene-isoprene copolymer, polyisoprene, natural rubber (NR), polyethylene glycol, polyisoprene, polybutadiene, polypropylene glycol, polytetrahydrofuran, polydimethylsiloxane, polyethylene, polypropylene And selected from the group consisting of ethylene-propylene copolymers, or styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene, and A polymer of an aromatic vinyl compound selected from the group consisting of 2,4,6-trimethylstyrene, or 1,3-butadiene, isoprene, 1,3-pentadiene, 2, A polymer of a conjugated diene compound selected from the group consisting of dimethylbutadiene, 2-phenyl-1,3-butadiene, and 1,3-hexadiene, or a copolymer of these aromatic vinyl compounds and conjugated diene compounds Is preferred. Of these, polycaprolactone is particularly preferred. In addition, in order to obtain a sufficient mechanical effect, in addition, from the viewpoint of easy inclusion in a cyclic molecule, workability at the time of rubber compounding, and productivity, the linear molecule or one branch point is provided. The number average molecular weight of the molecule is preferably 1,000 to 100,000, particularly preferably 1,000 to 100,000.

  Specific examples of the cyclic molecule include cyclodextrins, crown ethers, benzocrowns, dibenzocrowns, and dicyclohexanocrowns. Cyclodextrins are preferred, among which α, β, or γ-cyclodextrins and their derivatives are particularly preferred. In the case where the relationship between the bulkiness of the side chain of the molecule having a straight chain or one branch point and the inner diameter of the cyclic molecule is in a range having a relationship, it is easy to obtain the desired inclusions by efficiently associating them. Are known. For this reason, when a polymer such as polyethylene glycol or 1,4-cis polybutadiene having no bulky side chain is used as the linear or polymer having one branch point, α-cyclohexane having a small inner diameter is used. Dextrin and its derivatives are particularly preferred. The same applies to the case where polycaprolactone is used as the polymer having the straight chain or one branch point. On the other hand, when a polymer having a bulky side chain is used as the linear or polymer having one branch point, β- or γ-cyclodextrin having a larger inner diameter and derivatives thereof are preferably used. As an example of such a case, for example, when polyisobutylene or polydimethylsiloxane is used as the linear or polymer having one branch point, γ-cyclodextrin is preferably used.

  Further, as a specific example of the blocking group, if the blocking group is bulkier than the inner diameter of the cyclic molecule to be employed, the effect expected in the present invention can be satisfactorily exhibited. Mention may be made of phenyl groups, adamantyl groups, trityl groups, fluoresceins and pyrenes.

  In another preferred embodiment of the rubber composition of the present invention, the diameter of the inner surface of the cyclic molecule is the maximum diameter of the portion intended for inclusion of the linear molecule or the molecule having one branch point, which is the guest molecule to be included. It is preferable that it is larger than 3 times and not more than 3 times, more preferably not more than 2 times. Below this range, the cyclic molecule cannot be included, and inclusion above this range is difficult. This is thought to be due to insufficient energy reduction of the system during inclusion.

  Further, in the present invention, the inclusion amount of the cyclic molecule is the amount that the cyclic molecule can exist to the maximum on the linear molecule or the molecule having one branch point, that is, the linear molecule or one branch point. When the maximum amount of inclusion, which is the maximum amount of molecules that include a cyclic molecule, is 1, it is preferably 0.001 to 0.6, but is not limited to this range.

  The rubber component in the rubber composition of the present invention is mainly composed of an aromatic vinyl compound-conjugated diene compound copolymer, a conjugated diene compound polymer, or natural rubber. Specifically, natural rubber (NR), poly Examples include isoprene rubber (IR), polybutadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), and butyl rubber (IIR). These rubber components may be used alone or as a blend of two or more.

  When the rubber composition of the present invention is applied to a tire tread having improved winter performance, the rubber component is natural rubber (NR), polyisoprene rubber (IR), or polybutadiene rubber (BR). The rubber component is preferably a polybutadiene rubber (BR) having a vinyl content of 30% or less. This is because such polybutadiene rubber is soft at low temperatures and can improve the contact area, on-ice performance, snow brake performance, and the like. The glass transition temperature (Tg) of the rubber component is preferably 0 ° C. or lower, and more preferably −50 ° C. or lower. This is because, by having such a low glass transition temperature (Tg), the contact area, on-ice performance, and snow brake performance can be improved.

  In addition, the rubber composition of the present invention preferably contains at least one filler selected from the group consisting of carbon black and white filler in addition to the rubber component and the polyrotaxane or the crosslinked polyrotaxane. A plurality of these fillers can be used in combination. When the rubber composition of the present invention is applied particularly to a tire tread with improved winter performance, the amount of filler added to 100 parts by mass of the rubber component is preferably in the range of 5 to 200 parts by mass. The range of 20 to 100 parts by mass is more preferable, and when the rubber composition of the present invention is applied to the side reinforcing layer and / or bead filler, the amount of the filler added to 100 parts by mass of the rubber component is 10 To 100 parts by mass is preferred. If the amount of the filler is larger than this range, the workability is inferior and it becomes difficult to ensure the necessary flexibility due to the excessive elastic modulus. This is because necessary characteristics such as wear resistance are reduced. In addition, when applying the rubber composition of this invention to a side reinforcement layer and / or a bead filler, it is preferable to use carbon black as said filler. Carbon black that can be used in the present invention is not particularly limited, and those of FEF, SRF, HAF, ISAF, SAF grade, and the like can be used. By blending carbon black, various physical properties of the rubber composition can be improved, but HAF, ISAF, and SAF grades are particularly preferable from the viewpoint of improving wear resistance.

  On the other hand, examples of the white filler include silica and aluminum hydroxide, mixed oxides and hydroxides of silicon and aluminum, and among these, silica is preferable. The silica is not particularly limited, and examples thereof include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, and aluminum silicate. A plurality of these white fillers can be used in combination.

  In addition, when using a silica as a filler, it is preferable to add a silane coupling agent at the time of mix | blending from a viewpoint of improving the reinforcement property further. The silane coupling agent has a functional group that gives a silanol group when hydrolyzed and a functional group that can achieve chemical bonding by sulfur crosslinking with the main chain of the diene elastomer during the vulcanization reaction. 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 -Mercaptoethyltri Toxisilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl Tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-di Ethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthio Examples thereof include rubamoyl tetrasulfide, dimethoxymethylsilylpropylbenzothiazole tetrasulfide, and among these, bis (3-triethoxysilylpropyl) tetrasulfide, bis (3- Triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, and mixtures thereof are preferred. These silane coupling agents may be used alone or in combination of two or more.

In addition, when the rubber composition of the present invention is used for a tire tread with improved winter performance, an additive that generates independent bubbles on the tread surface when the tire is used can be further added. It is preferable because the water generated by the melting of ice and snow in the tread surface can be efficiently removed and the frictional force can be improved. Among them, it is preferable to add a foaming agent because the simplicity and the flexibility of the tread material can be maintained over a long period of time. Here, as the foaming agent, azodicarbonamide (ADCA), dinitrosopentamethylenetetramine (DNPT), dinitrosopentastyrenetetramine, a benzenesulfonylhydrazide derivative, p, p′-oxybisbenzenesulfonylhydrazide (OBSH), Ammonium bicarbonate that generates carbon dioxide, sodium bicarbonate, ammonium carbonate, nitrososulfonylazo compounds that generate nitrogen, N, N′-dimethyl-N, N′-dinitrosophthalamide, toluenesulfonylhydrazide, P-toluenesulfonyl Semicarbazide, P, P′-oxybisbenzenesulfonyl semicarbazide and the like can be mentioned. These foaming agents may be used individually by 1 type, and may use 2 or more types together. The foaming agent is preferably used in combination with urea, zinc stearate, zinc benzenesulfinate, zinc white or the like as a foaming aid. When a foaming agent is used, bubbles having a preferable size can be arranged in the rubber composition by appropriately controlling the pressure during vulcanization. In addition to the foaming agent, a method of blending a hollow material such as a microballoon can also be preferably used.

  When the rubber composition of the present invention is used for a tire tread with improved winter performance as described above, it preferably further contains organic short fibers made of a thermoplastic resin simultaneously with a foaming agent. It is further preferable to contain organic short fibers having thermal properties that melt or soften in the matrix of the rubber composition until the temperature reaches the maximum vulcanization temperature. The organic short fiber may be formed of a crystalline polymer, an amorphous polymer, or a crystalline polymer and an amorphous polymer. It is preferably formed from a functional polymer.

  Examples of the crystalline polymer include polyethylene (PE), polypropylene (PP), polybutylene, polybutylene succinate, polyethylene succinate, syndiotactic-1,2-polybutadiene (SPB), polyvinyl alcohol (PVA), Single-composition polymers such as polyvinyl chloride (PVC), those having a melting point controlled to an appropriate range by copolymerization, blending, or the like can be used, and those having additives added thereto can also be used. These may be used individually by 1 type and may use 2 or more types together. Among these crystalline polymers, polyolefins and polyolefin copolymers are preferable, polyethylene (PE) and polypropylene (PP) are more preferable in terms of general availability and availability, polyethylene (PE) in terms of low melting point and easy handling. Is particularly preferred. Examples of the non-crystalline polymer include polymethyl methacrylate (PMMA), acrylonitrile / butadiene / styrene copolymer (ABS), polystyrene (PS), polyacrylonitrile, copolymers thereof, and blends thereof. Etc. These may be used individually by 1 type and may use 2 or more types together.

  Although the average diameter of the said organic short fiber is not specifically limited, The range of 10-200 micrometers is preferable and the range of 15-150 micrometers is still more preferable. The average length of the organic short fibers is not particularly limited, but is preferably in the range of 0.2 to 10 mm, and more preferably in the range of 1 to 10 mm. In this case, after vulcanization, elongated bubbles can be suitably formed in the rubber matrix, and the elongated bubbles can function as micro drainage grooves, improving the performance of vulcanized rubber on ice. Can be made. In addition, the compounding quantity of the said organic short fiber has the preferable range of 0.2-10 mass parts with respect to 100 mass parts of said rubber components.

  The organic short fibers are preferably fine particle-containing organic short fibers in which at least a part thereof contains fine particles. When the fine particle-containing organic short fibers are blended, the on-ice performance of the rubber composition is further improved by the scratching effect of the fine particles. Examples of the fine particles include inorganic fine particles such as glass fine particles, aluminum hydroxide fine particles, alumina fine particles, and iron fine particles, and organic fine particles such as (meth) acrylic resin fine particles and epoxy resin fine particles. These fine particles may be used individually by 1 type, and 2 or more types may be mixed and used for them. The particle diameter of the fine particles is not particularly limited, but the long diameter (the longest diameter of the fine particles) is preferably in the range of 0.1 to 200 μm, and 80% or more of the total fine particles are 0.1 to 200 μm. More preferably, it has a major axis in the range of. The content of the fine particles in the fine particle-containing organic short fibers is preferably in the range of 3 to 145 parts by mass with respect to 100 parts by mass of the organic short fibers made of a thermoplastic resin. If the content of the fine particles is less than parts by mass, the scratching effect by the fine particles may be insufficient, and the performance on ice may not be sufficient. On the other hand, if the content exceeds 145 parts by mass, the spinning operability of the fine organic particles containing fine particles is deteriorated. Tend.

  In the rubber composition of the present invention, a general rubber crosslinking agent can be used, and it is preferable to use a combination of a crosslinking agent and a vulcanization accelerator. Here, as a crosslinking agent, sulfur etc. are mentioned, and the usage-amount of a crosslinking agent has the preferable range of 0.1-10 mass parts as a sulfur content with respect to 100 mass parts of said rubber components, and is 1-5 mass parts. The range of is more preferable. If the blending amount of the crosslinking agent is less than 0.1 parts by mass with respect to 100 parts by mass of the rubber component, the fracture strength, wear resistance and low heat build-up of the vulcanized rubber are reduced, Rubber elasticity is lost. In addition, when applying the rubber composition of the present invention to the side reinforcing layer and / or bead filler, it is preferable to use sulfur among the cross-linking agents. In this case, the sulfur content in the rubber composition is the above rubber component. It is preferable that it is 2 mass parts or more with respect to 100 mass parts. Sulfur is the most commonly used vulcanizing agent, and the desired vulcanizing effect can be achieved by blending 2 parts by mass or more.

  On the other hand, the vulcanization accelerator is not particularly limited, but 2-mercaptobenzothiazole (M), dibenzothiazyl disulfide (DM), N-cyclohexyl-2-benzothiazylsulfenamide (CZ). ), Thiazole vulcanization accelerators such as Nt-butyl-2-benzothiazolylsulfenamide (NS), and guanidine vulcanization accelerators such as diphenylguanidine (DPG). The amount of the vulcanization accelerator used is preferably in the range of 0.1 to 5 parts by mass, more preferably in the range of 0.2 to 3 parts by mass with respect to 100 parts by mass of the rubber component. These vulcanization accelerators may be used alone or in combination of two or more.

  In the rubber composition of the present invention, process oil or the like can be used as a softening agent, and examples of the process oil include paraffinic oil, naphthenic oil, and aromatic oil. Among these, aromatic oils are preferable from the viewpoint of tensile strength and wear resistance, and naphthenic oils and paraffinic oils are preferable from the viewpoint of hysteresis loss and low-temperature characteristics. The amount of these process oils used is preferably in the range of 100 parts by mass or less, more preferably in the range of 30 parts by mass or less, relative to 100 parts by mass of the rubber component. When the amount of process oil used exceeds 100 parts by mass with respect to 100 parts by mass of the rubber component, the tensile strength, wear resistance, and low heat build-up of the vulcanized rubber tend to deteriorate.

  In a preferred embodiment of the present invention, the rubber composition includes the rubber component, polyrotaxane or cross-linked polyrotaxane, filler, silane coupling agent, foaming agent, foaming aid, organic short fiber, cross-linking agent, and vulcanization. In addition to accelerators and softeners, for example, anti-aging agents, zinc oxide, stearic acid, antioxidants, ozone deterioration inhibitors, and other additives normally used in the rubber industry are within the range that does not impair the purpose of the present invention. It can select and mix | blend suitably. The physical properties of the rubber composition can be adjusted by appropriately selecting the type of rubber component and compounding agent to be used and the compounding ratio thereof.

  The rubber composition of the present invention is obtained by kneading using a kneading machine such as a roll or an internal mixer, and after molding, vulcanization is performed, and the tire tread, undertread, carcass, sidewall, It can be used for tire applications such as beads, anti-vibration rubber, belts, hoses, and other industrial products, but is particularly suitable as a tire tread, side reinforcing layer, and bead filler.

  The tire of the present invention is characterized by using the rubber composition in a tread. The tire is excellent in dry performance, on-ice performance and wear performance because a rubber composition containing a crosslinked polyrotaxane having low elasticity at low temperatures and high elasticity at high temperatures is applied to the tread. In addition, the tire of this invention can be manufactured in accordance with a conventional method. Moreover, as gas with which this tire is filled, inert gas, such as nitrogen, argon, helium other than normal or the air which adjusted oxygen partial pressure, can be used.

  Next, an embodiment of a tire in which the rubber composition of the present invention is applied to a side reinforcing layer and / or a bead filler will be described with reference to the drawings. FIG. 1 is a cross-sectional view in the width direction showing one embodiment of the pneumatic tire of the present invention. The tire shown in FIG. 1 has a pair of left and right bead portions 1 and a pair of sidewall portions 2 and a tread portion 3 connected to both sidewall portions 2, and extends in a toroidal shape between the pair of bead portions 1. A radial carcass 4 that reinforces each of these parts 1, 2, 3, a belt 5 composed of at least two belt layers arranged on the outer side in the tire radial direction of the carcass 4, and embedded in the bead part 1, respectively. A bead filler 7 disposed on the outer side in the tire radial direction of the ring-shaped bead core 6 and a pair of side reinforcing layers 8 disposed on the innermost side surface of the carcass 4 of the sidewall portion 2 are provided.

  In the illustrated tire, the radial carcass 4 includes a folded carcass ply 4a and a down carcass ply 4b, and both end portions of the folded carcass ply 4a are folded around the bead core 6 to form folded ends. The structure and the number of plies of the radial carcass 4 are not limited to this. The bead filler 7 is disposed between the main body portion of the folded carcass ply 4a and the folded end portion thereof on the radially outer side of the bead core 6, and the down carcass ply 4b is a folded end portion of the folded carcass ply 4a. Arranged outside. The side reinforcing layer 8 is disposed inside the folded carcass ply 4a mainly at the sidewall portion 2. Here, the maximum thickness of the side reinforcing layer 8 is preferably 6 to 13 mm. The shape of the side reinforcing layer 8 in the illustrated example has a crescent-shaped cross section, but the cross-sectional shape is not particularly limited as long as it has a side reinforcing function.

  In the pneumatic tire of the present invention, the rubber composition having the specific physical properties described above is applied to at least one of the bead filler 7 and the side reinforcing layer 8 to improve the riding comfort during normal running of the tire. In addition, run flat durability can be dramatically improved.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

  A polycaprolactone-carboxylated product (Production Example 1), a polyrotaxane (Production Example 2), and a crosslinked polyrotaxane (Production Example 3) were synthesized by the following method.

(Production Example 1: Synthesis of polycaprolactone-carboxylated product)
10 g of polycaprolactone (PCL) having a molecular weight of 5,000, 100 mg of TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy radical), and 1 g of sodium bromide were dissolved in 100 ml of acetone. 5 ml of a commercially available sodium hypochlorite aqueous solution (effective chlorine concentration 5%) was added and stirred at room temperature for 10 minutes. In order to decompose the remaining sodium hypochlorite, ethanol was added in a range up to 5 ml to complete the reaction. Subsequently, the solution was distilled off with an evaporator, dissolved in 250 ml of warm ethanol, and then allowed to stand overnight in a freezer (about −4 ° C.) to precipitate only the PCL-carboxylated product, which was collected and dried.

(Production Example 2: Synthesis of polyrotaxane)
0.2 g of PCL-carboxylate prepared as described above was dissolved in 50 ml of acetone, while 7.25 g of α-CD (cyclodextrin) was dissolved in 50 ml of water. After both were heated to 70 ° C., the PCL-carboxylate solution was added little by little to the α-CD aqueous solution and sonicated at 70 ° C. for 17 minutes. Next, the precipitate obtained by allowing to stand for 10 hours was collected and dried to obtain an inclusion complex.

  At room temperature, 10 g of DMF (dimethylformamide) in 3 g of BOP (benzotriazol-1-yl-oxy-tris- (dimethylamino) phosphonium hexafluorophosphate) reagent, 1 g of HOBt (1-hydroxybenzotriazole), adamantamine 1 0.4 g and 1.25 ml of diisopropylethylamine were dissolved in this order. The obtained solution was added to 14 g of the clathrate complex obtained above dispersed in 20 ml of a DMF / DMSO mixed solvent (75/25), and quickly and sufficiently shaken. The slurry sample was allowed to stand overnight in a refrigerator, and then 50 ml of a mixed solution of DMF / methanol = 1: 1 was added and mixed well, followed by centrifugation to discard the supernatant. This washing with the DMF / methanol mixed solution was repeated twice, and further washing with 100 ml of methanol was repeated twice by the same centrifugation. The obtained precipitate was vacuum-dried and then dissolved in 50 ml of DMSO, and the obtained transparent solution was dropped into 700 ml of water to precipitate polyrotaxane. The precipitated polyrotaxane was collected by centrifugation and vacuum-dried or freeze-dried. The cycle of dissolution in DMSO, precipitation in water, recovery, and drying was repeated twice to finally obtain a polyrotaxane blocked with a purified adamantyl group (blocked polyrotaxane).

(Production Example 3: Synthesis of crosslinked polyrotaxane 1)
Dissolve 10 g of the above blocked polyrotaxane 1 in 200 ml of DMF to obtain a solution, add a separately prepared 3.5 g of cyanuric chloride in DMF in 250 ml, add 50 ml of 1N aqueous sodium hydroxide solution, and at room temperature for 3 hours. A cross-linked polyrotaxane gel was obtained by reaction. Thereafter, the solvent was removed according to a conventional method to obtain a crosslinked polyrotaxane.

Next, using the polyrotaxane 1 or 2, or the crosslinked polyrotaxane 1 or 2, a rubber composition having a compounding formulation shown in Table 1 was prepared a plurality of times, and the prepared rubber composition was used for molding a tire. That is, by applying the obtained rubber composition to a tread, a studless tire having a size of 185 / 70R13 was prototyped. In addition, G 'of the obtained studless tire
The performance on ice, wet performance, dry performance and wear performance were evaluated by the following methods. The results are shown in Table 1.

(1) Measuring method of storage elastic modulus G ′ Using a viscoelasticity measuring device manufactured by Rheometrics, temperature −20 ° C. (strain 0.1%), 0 ° C. (strain 0.1%), 60 ° C. (strain 5) %), And the storage elastic modulus (G ′) was measured at a frequency of 15 Hz.
In Table 1, the rubber composition of Comparative Example 1 and the storage elastic modulus (G ′) are each shown as an index of 100. Regarding the storage elastic modulus (G ′), the smaller values of −20 ° C. and 0 ° C. are better for increasing the contact area, and the higher G ′ at 60 ° C., the better the driving stability and the dry brake performance are. It is.

(2) Performance on ice The above four test tires were mounted on a passenger car with a displacement of 1600 cc, and braking performance on ice at an ice temperature of −1 ° C. was confirmed. Specifically, the vehicle travels on a flat surface on ice, steps on the brake at a speed of 20 km / h, locks the tire, measures the distance (braking distance) until it stops, and the following formula:
Performance on ice = braking distance of tire of comparative example 1 / braking distance of test tire × 100 (index)
According to the index. The larger the index value, the shorter the braking distance and the better the braking performance on ice.

(3) Wet performance The above four test tires were mounted on a 1600 cc passenger car, and the braking performance on the water was confirmed. Specifically, the vehicle travels on a flat water surface, steps on the brake at a speed of 20 km / h, locks the tire, measures the distance (braking distance) until it stops, and the following formula:
Wet performance = braking distance of tire of Comparative Example 1 / braking distance of test tire × 100 (index)
According to the index. The larger the index value, the shorter the braking distance and the better the braking performance on water.

(4) Dry performance The above four test tires were mounted on a 1600 cc passenger car, and the tire dry performance was expressed by a driver's feeling score in an actual vehicle test on a dry road surface. The higher the score, the better the dry performance.

(5) Abrasion performance The above test tires are mounted on a 1600cc displacement passenger car, and a running test of 50000km is conducted in urban areas and mountain slopes under the load equivalent to two passengers. The depth was measured. In the measurement of the shallow groove, an average value of 10 circumferential positions in the groove in the vicinity of the center was used, and the comparative example 1 was set to 100 and displayed as an index. Larger numbers are better.

  Table 1 shows the results of Examples 1 to 5 and 12 and Comparative Examples 1 to 7. In Example 1, a studless tire in which a rubber composition containing 10 phr of an uncrosslinked polyrotaxane was applied to a tread was examined. In Example 2, a studless tire in which a rubber composition containing 10 phr of a crosslinked polyrotaxane was applied to a tread was examined. In Example 3, for a studless tire in which a rubber composition containing 10 phr of an uncrosslinked polyrotaxane was applied to a tread, a cyanuric chloride DMF solution (14 g / L) was applied to the tread of an unvulcanized tire and then vulcanized. Then, the case where the crosslinking reaction and the vulcanization reaction were carried out in parallel was examined. Similarly, in Example 12, after the polyrotaxane was blended, the crosslinking agent (1,8-diisocyanate octane) in the amount shown in Table 1 was blended and vulcanized to simultaneously perform the crosslinking reaction and the vulcanization reaction in parallel. We also examined what was done. In Example 4, a studless tire in which a rubber composition in which the number of blended parts of natural rubber (NR) was increased was applied to a tread was examined. In Example 5, a studless tire in which a rubber composition having an increased number of blended parts of polybutadiene rubber (BR) was applied to a tread was examined. On the other hand, in the comparative example, a studless tire in which a rubber composition (Comparative Examples 1 and 3 to 7) containing no polyrotaxane or crosslinked polyrotaxane was applied to a tread and 10 phr of the polycaprolactone-carboxylated product prepared in Production Example 1 were blended. The studless tire which applied the rubber composition (comparative example 2) to the tread was examined.

* 1 UBEPOL 150L
* 2 N134 (N2SA: 146 m ² / g)
* 3 Nipsil AQ (manufactured by Nippon Silica Co., Ltd.)
* 4 Si69 (Degussa)
* 5 N-isopropyl-N'-phenyl-P-phenylenediamine * 6 Dibenzothiazyl sulfide * 7 N-cyclohexyl-2-benzodiazol sulfenamide * 8 Dinitropentamethylenetetramine

When a rubber composition containing no polyrotaxane (Example 1) or a crosslinked polyrotaxane (Example 2) is applied to a tread of a studless tire, and a rubber composition not containing a polyrotaxane or a crosslinked polyrotaxane is used (Comparative Example 1). It was found that the G ′ at 60 ° C., the performance on ice, the wet performance, the dry performance and the wear performance were clearly improved as compared with the above. Similarly, when tread vulcanization and polyrotaxane crosslinking were carried out after blending polyrotaxane (Examples 3 and 12), G ′ at 60 ° C., performance on ice, wet performance, dry performance, and wear performance were also evident. Improvement was observed. Even when the blending part of natural rubber (NR) is increased (Example 4) and when the blending part of polybutadiene rubber (BR) is increased (Example 5), G ′ at 60 ° C., performance on ice, wet performance, A clear improvement in dry and wear performance was observed. On the other hand, when the rubber composition containing the PCL-carboxylated product was applied to the tread (Comparative Example 2), such an effect was not recognized. The same applies to Comparative Examples 3 to 7, and the result that the wear performance and the like were inferior was obtained.

  Next, the rubber composition of the mixing | blending prescription shown in following Table 2 and Table 3 was prepared using said PCL- carboxylated thing, a polyrotaxane, and a bridge | crosslinking polyrotaxane, and the prepared rubber composition was used for shaping | molding of a tire. That is, the rubber composition was applied to side reinforcing rubber (Table 2), or side reinforcing rubber and bead filler rubber (Table 3), and a run flat tire having a size of 185 / 70R13 was prototyped. About the run flat tire, run flat durability and riding comfort were measured by the method shown below.

(6) Run flat durability Each test tire is assembled at rim at atmospheric pressure, filled with 230kPa internal pressure, left in a room at 38 ℃ for 24 hours, then the valve core is removed, and the tire internal pressure is taken as atmospheric pressure. A drum running test was conducted under the conditions of 4.17 kN (425 kg), speed 89 km / h, and room temperature 38 ° C. The travel distance until failure of each sample tire was measured, and the travel distance of Comparative Example 8 or 10 was taken as an index 100, and the index was displayed by the following formula. The larger the index, the better the run flat durability.
Run-flat durability (index) = (travel distance of sample tire / travel distance of tire of Comparative Example 8 or 10) × 100

(7) Riding comfort Each prototype tire was mounted on a passenger car, and a feeling test of riding comfort was conducted by two specialized drivers, and a score of 1 to 10 was assigned to obtain an average value. It shows that riding comfort is so favorable that this value is large.

  Table 2 shows the results of Examples 6 to 8 and Comparative Examples 8 and 9. In Example 6, a run flat tire in which a rubber composition containing 10 phr of a non-crosslinked polyrotaxane was applied to a side reinforcing rubber was examined. In Example 7, a run flat tire in which a rubber composition containing 10 phr of a crosslinked polyrotaxane was applied to a side reinforcing rubber was examined. In Example 8, for a run-flat tire in which a rubber composition containing 10 phr of an uncrosslinked polyrotaxane was applied to a side reinforcing rubber, a toluene solution of cyanuric chloride (14 g / L) was applied to the side reinforcing rubber of an unvulcanized tire. Then, vulcanization was performed, and a cross-linking reaction and a vulcanization reaction that were performed in parallel were examined. On the other hand, in the comparative example, a rubber composition containing no polyrotaxane or crosslinked polyrotaxane (Comparative Example 8) applied to a side reinforcing rubber and a rubber composition containing 10 phr of a PCL-carboxylated product (Comparative Example 9). The run-flat tire was applied to the side reinforcement rubber.

  Table 3 shows the results of Examples 9 to 11 and 13 and Comparative Examples 10 and 11. In Example 9, a run flat tire in which a rubber composition containing 10 phr of uncrosslinked polyrotaxane was applied to a side reinforcing rubber and a bead filler rubber was examined. In Example 10, a run flat tire in which a rubber composition containing 10 phr of a crosslinked polyrotaxane was applied to a side reinforcing rubber and a bead filler rubber was examined. In Example 11, a run-flat tire in which a rubber composition containing 10 phr of a non-crosslinked polyrotaxane was applied to a side reinforcing rubber and a bead filler rubber, a cyanuric chloride DMF solution (14 g / L) was used as a side reinforcing rubber for an unvulcanized tire. Were applied to bead filler rubber and then vulcanized, and the cross-linking reaction and vulcanization reaction were performed in parallel at the same time. Similarly, in Example 13, after the polyrotaxane was blended, the crosslinking agent (1,8-diisocyanate octane) in the amount shown in Table 3 was blended and vulcanized to simultaneously perform the crosslinking reaction and the vulcanization reaction in parallel. We also examined what was done. On the other hand, in a comparative example, a rubber composition containing no polyrotaxane or a crosslinked polyrotaxane (Comparative Example 10) applied to a side reinforcing rubber and a bead filler rubber, and a rubber composition containing 10 phr of a PCL-carboxylated product ( A run flat tire in which Comparative Example 11) was applied to side reinforcing rubber and bead filler rubber was examined.

* 1 UBEPOL 150L
* 2 N134 (N2SA: 146 m ² / g)
* 3 N-isopropyl-N'-phenyl-P-phenylenediamine * 4 N-cyclohexyl-2-benzodiazolsulfenamide

* 1 UBEPOL 150L
* 2 N134 (N2SA: 146 m ² / g)
* 3 N-isopropyl-N'-phenyl-P-phenylenediamine * 4 N-cyclohexyl-2-benzodiazolsulfenamide

  By applying the rubber composition containing the polyrotaxane (Example 6) or the crosslinked polyrotaxane (Example 7) to the side reinforcing rubber, compared with the case where the polyrotaxane or the crosslinked polyrotaxane is not compounded (Comparative Example 8), the run It was found that the flat durability and ride comfort index are clearly improved. In addition, even when the side reinforcing rubber is crosslinked simultaneously with the crosslinking of the polyrotaxane after blending the polyrotaxane (Example 8), the run-flat durability and the ride comfort index are obvious as in the case of blending the crosslinked polyrotaxane. Improvement was observed. In addition, when the rubber composition which mix | blended PCL-carboxylated material was applied to the side reinforcement rubber (comparative example 9), the improvement of run-flat durability and a riding comfort index was not recognized.

  By applying the rubber composition containing the polyrotaxane or the crosslinked polyrotaxane to the side reinforcing rubber and the bead filler rubber (Examples 9 and 10), compared with the case where the polyrotaxane or the crosslinked polyrotaxane is not compounded (Comparative Example 10), the run It was found that the flat durability and ride comfort index are clearly improved. Even when the side reinforcing rubber and the bead filler rubber are vulcanized simultaneously with the crosslinking of the polyrotaxane after blending the polyrotaxane (Examples 11 and 13), the run-flat durability is the same as when the crosslinked polyrotaxane is blended. A clear improvement in the ride comfort index was observed. In addition, when the rubber composition which mix | blended PCL-carboxylated material was applied to side reinforcement rubber and bead filler rubber (comparative example 11), the improvement of run-flat durability and a riding comfort index was not recognized.

  Furthermore, when the rubber composition containing the polyrotaxane or the crosslinked polyrotaxane is applied only to the side reinforcing rubber (Examples 6 to 8), and when applied to the side reinforcing rubber and the bead filler rubber (Examples 9 to 11 and 13). In comparison, the latter showed a tendency to improve the run-flat durability and the ride comfort index.

  According to the present invention, a tire having improved performance on ice, dry performance, and wear performance can be provided by using a rubber composition containing a polyrotaxane or a crosslinked polyrotaxane in a tread.

  Further, according to the present invention, by using a rubber composition containing a polyrotaxane or a crosslinked polyrotaxane for a side reinforcing layer, or a side reinforcing layer and a bead filler, run flat durability during run flat running and normal running running A pneumatic tire with improved riding comfort can be provided.

DESCRIPTION OF SYMBOLS 1 Bead part 2 Side wall part 3 Tread part 4 Radial carcass 4a Folded carcass ply 4b Down carcass ply 5 Belt 6 Bead core 7 Bead filler 8 Side reinforcement layer

Claims (30)

An aromatic vinyl compound-conjugated diene compound copolymer, or a conjugated diene compound polymer, or a rubber component mainly composed of natural rubber;
A cyclic molecule, a linear molecule that includes the cyclic molecule in a skewered manner, or a molecule having one branch point, and a terminal molecule of the linear molecule or molecule having one branch point. A polyrotaxane having a blocking group for preventing separation, or a crosslinked polyrotaxane in which the polyrotaxane is crosslinked via a cyclic molecule,
A rubber composition comprising 0.1 to 20 parts by mass of the polyrotaxane or the crosslinked polyrotaxane with respect to 100 parts by mass of the rubber component.   The rubber composition according to claim 1, wherein the aromatic vinyl compound is styrene, and the conjugated diene compound is isoprene or butadiene.   The aromatic vinyl compound-conjugated diene compound copolymer, the conjugated diene compound polymer, or the rubber component mainly composed of natural rubber is natural rubber and / or polyisoprene rubber, polybutadiene rubber, and styrene-butadiene copolymer. 2. The rubber composition according to claim 1, wherein at least one of the polymers is a main component.   The aromatic vinyl compound-conjugated diene compound copolymer, conjugated diene compound polymer, or rubber component mainly composed of natural rubber is composed mainly of natural rubber and / or polyisoprene rubber and polybutadiene rubber. 2. The rubber composition according to claim 1, wherein the rubber composition is one.   The rubber composition according to claim 1, wherein the polyrotaxane linear molecule or the molecule having one branch point has an affinity for the rubber component. The rubber composition according to claim 1, wherein the linear molecule of the polyrotaxane or the molecule having one branch point is selected from one of the following.
Polycaprolactone, natural rubber (NR), polyvinyl alcohol, polyvinylpyrrolidone, poly (meth) acrylic acid, cellulose resin (carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose), polyacrylamide, polyethylene oxide, polyethylene glycol, polyvinyl acetal resin , Polyvinyl methyl ether, polyamine, polyethyleneimine, casein, gelatin, starch and / or copolymers thereof, polyethylene, polypropylene, ethylene-propylene copolymer, polyisobutene, isobutene-isoprene copolymer, polyisoprene, polyester resin, Polyvinyl chloride resin, polystyrene, polystyrene resin of acrylonitrile-styrene copolymer resin, polymer Methacrylate, (meth) acrylic acid ester copolymer, acrylic resin of acrylonitrile-methyl acrylate copolymer resin, polycarbonate resin, polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, polyvinyl butyral resin; styrene, α-methylstyrene Polymers of aromatic vinyl compounds of 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene and 2,4,6-trimethylstyrene; 1,3-butadiene, isoprene, 1, Polymers of conjugated diene compounds of 3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, and 1,3-hexadiene; and copolymers of these aromatic vinyl compounds and conjugated diene compounds   The rubber composition according to any one of claims 1 to 6, wherein the linear molecule of the polyrotaxane or the molecule having one branch point is hydrophobic.   The linear molecule or the molecule having one branch point is polycaprolactone, styrene-butadiene copolymer, isobutene-isoprene copolymer, polyisoprene, natural rubber (NR), polyethylene glycol, polyisoprene, polyisobutylene, One selected from the group consisting of polybutadiene, polypropylene glycol, polytetrahydrofuran, polydimethylsiloxane, polyethylene polypropylene, and ethylene-propylene copolymer, or styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyl A polymer of an aromatic vinyl compound selected from the group consisting of toluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene and 2,4,6-trimethylstyrene, or 1,3-butadiene A polymer of a conjugated diene compound selected from the group consisting of isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene and 1,3-hexadiene, or a fragrance thereof. The rubber composition according to any one of claims 1 to 7, wherein the rubber composition is a copolymer of an aromatic vinyl compound and a conjugated diene compound.   The rubber composition according to any one of claims 1 to 8, wherein a molecular weight of the linear molecule or a molecule having one branch point is 1,000 to 100,000.   The rubber composition according to any one of claims 1 to 9, wherein the cyclic molecule is selected from the group consisting of cyclodextrin, crown ether, benzocrown, dibenzocrown and dicyclohexanocrown. .   The rubber composition according to any one of claims 1 to 10, wherein the cyclic molecule is cyclodextrin.   The rubber composition according to any one of claims 1 to 11, wherein the cyclic molecule is α, β, or γ-cyclodextrin.   The rubber composition according to any one of claims 1 to 12, wherein the cyclic molecule is α-cyclodextrin.   The rubber composition according to any one of claims 1 to 13, wherein the blocking group is selected from the group consisting of a dinitrophenyl group, an adamantyl group, a trityl group, fluorescein, and pyrene.   The diameter of the inner surface of the cyclic molecule is larger than the maximum diameter of the above-mentioned linear molecule, which is a guest molecule to be included, or the portion intended to include a molecule having one branch point, and does not exceed three times that. The rubber composition according to claim 1, wherein   The diameter of the inner surface of the cyclic molecule is larger than the maximum diameter of the above-mentioned linear molecule, which is a guest molecule to be included, or a portion intended to include a molecule having one branch point, and does not exceed twice that. The rubber composition according to claim 1, wherein   The inclusion amount of the cyclic molecule is 0.001 to 0.6, where 1 is the maximum inclusion amount, which is the maximum amount that the linear molecule or the molecule having one branch point includes the cyclic molecule. The rubber composition according to any one of claims 1 to 16, wherein: The rubber composition according to claim 1, wherein the cross-linking agent used for cross-linking of the polyrotaxane cyclic molecules of the polyrotaxane has at least two functional groups selected from the following group in the molecule.
Carboxylic acid halide group, isocyanuric acid halide group, isocyanate group, alkoxysilyl group, epoxy group, imidazolyl group, vinyl group, The cross-linking agent used for cross-linking the polyrotaxane cyclic molecules of the polyrotaxane is cyanuric chloride, trimesoyl chloride, terephthaloyl chloride, epichlorohydrin, dibromobenzene, glutaraldehyde, phenylene diisocyanate and partial condensates thereof, diisocyanic acid The rubber according to any one of claims 1 to 18, wherein the rubber is selected from the group consisting of trilein, 1,8-diisocyanate octane, divinylsulfone, 1,1'-carbonyldiimidazole and alkoxysilane. Composition.   The polyrotaxane is blended in a rubber composition, and the crosslinking material is added by coating, impregnation, or blending, and the cyclic molecules are crosslinked by heat treatment. The manufacturing method of the rubber composition of description.   A rubber composition produced by the production method according to claim 20.   The rubber component includes natural rubber (NR), polyisoprene rubber (IR), polybutadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR) and butyl rubber ( The rubber composition according to any one of claims 1 to 19 and 21, wherein the rubber composition is selected from the group consisting of IIR).   The rubber composition according to any one of claims 1 to 19 and 21 to 22, wherein a glass transition temperature (Tg) of the rubber component is 0 ° C or lower.   The rubber composition according to any one of claims 1 to 19, and 21 to 23, wherein the rubber component is polybutadiene rubber (BR) having a vinyl content of 30% or less.   The rubber composition according to claim 22, wherein the rubber component comprises natural rubber (NR) and cis-1,4-polybutadiene rubber (BR).   26. Any one of claims 1 to 19 and 21 to 25, further comprising at least one filler selected from the group consisting of carbon black and white filler. The rubber composition according to item 1.   A tire using the rubber composition according to any one of claims 1 to 19 and 21 to 26 for a tread. A radial carcass having a pair of bead portions and a pair of sidewall portions, and a tread portion connected to both sidewall portions, extending in a toroidal shape between the pair of bead portions, and reinforcing the respective portions; In a pneumatic tire comprising a bead filler disposed on the outer side in the tire radial direction of a bead core embedded in each bead portion, and a pair of side reinforcing layers disposed on the inner surface of the carcass of the sidewall portion,
The rubber composition according to any one of claims 1 to 19 and claim 21 to claim 26, further comprising sulfur and a filler, as the rubber composition of the side reinforcing layer and / or the bead filler. Pneumatic tire characterized by.   The rubber composition contains 0.1 to 20 parts by mass of the polyrotaxane or the crosslinked polyrotaxane, 2 parts by mass or more of the sulfur, and 10 to 100 parts by mass of the filler with respect to 100 parts by mass of the rubber component. The pneumatic tire according to claim 28.   30. The pneumatic tire according to claim 28 or 29, wherein the filler is carbon black.

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