JP5689393B2 - Composition for inner liner for pneumatic tire - Google Patents

Description

  The present invention relates to a composition for an inner liner for a pneumatic tire excellent in heat resistance and adhesion to a carcass.

  Conventionally, butyl rubber has been used in various fields as a gas-permeable material. For example, it is used as a material for medicine plugs and tire inner liners. However, when used as a material for a tire inner liner, there is a problem that the operability is poor because a vulcanization operation is required.

  In order to solve the above-mentioned problems, the present inventors have so far developed a technology for copolymerizing β-pinene as a third monomer with an isobutylene-styrene block copolymer, and this block copolymer is a gas. It has been found that it exhibits properties excellent in permeability, flexibility, toughness, and adhesion to carcass rubber, and has been reported to be useful as an inner liner for pneumatic tires (Patent Documents 1 and 2).

  However, it has been found that even the β-pinene-containing isobutylene-styrene block copolymer may still have insufficient adhesion to carcass rubber, and an improvement measure has been demanded. That is, there is a demand for a technique for further improving the adhesion to the carcass rubber without reducing the heat resistance of the inner liner layer.

JP 2010-195864 A JP 2010-195969 A

  The present invention has been made in view of the above problems, and is an inner liner layer for a pneumatic tire that does not require a vulcanization step, and is an inner for a pneumatic tire that is excellent in heat resistance and adhesion to a carcass. It is providing the composition for liners.

  As a result of intensive investigations to achieve the above object, the present inventors have completed the present invention.

  That is, the present invention is an isobutylene block copolymer comprising a polymer block (a) mainly composed of isobutylene and a polymer block (b) mainly composed of an aromatic vinyl compound, wherein (a) or ( At least one block of b) is a copolymer with β-pinene, and hydrogenated with 100 parts by weight of an isobutylene block copolymer (A) having a number average molecular weight of 110,000 to 500,000. It is related with the composition for inner liners for pneumatic tires containing 0.1-200 weight part of terpene resin (B) which is not.

  As a preferred embodiment, an inner liner for a pneumatic tire, in which the isobutylene block copolymer (A) is obtained by copolymerizing β-pinene in a polymer block (b) mainly composed of an aromatic vinyl compound. The present invention relates to a composition for use.

  As a preferred embodiment, the present invention relates to a composition for an inner liner for a pneumatic tire in which the content of β-pinene in the isobutylene block copolymer (A) is 0.01 to 50% by weight.

  As a preferred embodiment, a pneumatic tire in which the block structure of the isobutylene block copolymer is a diblock body of (a)-(b) or a triblock body of (b)-(a)-(b). The present invention relates to a composition for an inner liner.

  As a preferred embodiment, the present invention relates to a composition for an inner liner for a pneumatic tire in which the molecular weight distribution (weight average molecular weight / number average molecular weight) of the isobutylene block copolymer (A) is 1.5 or less.

  As a preferred embodiment, the isobutylene block copolymer (A) contains 60 to 90% by weight of the polymer block (a) mainly composed of isobutylene, and 10 blocks (b) mainly composed of an aromatic vinyl compound. The present invention relates to a composition for an inner liner for a pneumatic tire containing -40% by weight.

  As a preferred embodiment, the present invention relates to a composition for an inner liner for a pneumatic tire in which the aromatic vinyl compound is styrene.

  As a preferred embodiment, the non-hydrogenated terpene resin (B) is a polymer composed of only a terpene monomer, or a copolymer of a terpene monomer and an aromatic monomer. The present invention also relates to a composition for an inner liner for a pneumatic tire, which is a non-hydrogenated terpene resin that is a polymer having an aromatic monomer content of 95% by weight or less.

  The inner liner for a tire made by the composition for an inner liner for a pneumatic tire of the present invention is excellent in adhesion to the carcass without going through a vulcanization step, further excellent in heat resistance, and excellent in its balance, It is suitable for simplifying tire assembly and improving the durability of the inner liner.

  The present invention relates to an isobutylene block copolymer comprising a polymer block (a) mainly composed of isobutylene and a polymer block (b) mainly composed of an aromatic vinyl compound, wherein (a) or (b ) At least one block is a copolymer with β-pinene, and 100 parts by weight of an isobutylene block copolymer (A) having a number average molecular weight of 110,000 to 500,000 is not hydrogenated. A composition for an inner liner for a pneumatic tire containing 0.1 to 200 parts by weight of a terpene resin (B).

<Isobutylene block copolymer (A)>
The isobutylene block copolymer (A) is an isobutylene block copolymer comprising a polymer block (a) mainly composed of isobutylene and a polymer block (b) mainly composed of an aromatic vinyl compound. , At least one block is a random copolymer containing β-pinene.

  The polymer block (a) containing isobutylene as a main component is a polymer block composed of 60% by weight or more, preferably 80% by weight or more of units derived from isobutylene.

  The polymer block (b) mainly composed of an aromatic vinyl compound is a polymer block composed of 60% by weight or more, preferably 80% by weight or more of units derived from an aromatic vinyl compound.

  Aromatic vinyl compounds include styrene, o-, m- or p-methylstyrene, α-methylstyrene, β-methylstyrene, 2,6-dimethylstyrene, 2,4-dimethylstyrene, α-methyl-o. -Methylstyrene, α-methyl-m-methylstyrene, α-methyl-p-methylstyrene, β-methyl-o-methylstyrene, β-methyl-m-methylstyrene, β-methyl-p-methylstyrene, 2 , 4,6-trimethylstyrene, α-methyl-2,6-dimethylstyrene, α-methyl-2,4-dimethylstyrene, β-methyl-2,6-dimethylstyrene, β-methyl-2,4-dimethyl Styrene, o-, m- or p-chlorostyrene, 2,6-dichlorostyrene, 2,4-dichlorostyrene, α-chloro-o-chlorostyrene, α-chloro-m- Chlorostyrene, α-chloro-p-chlorostyrene, β-chloro-o-chlorostyrene, β-chloro-m-chlorostyrene, β-chloro-p-chlorostyrene, 2,4,6-trichlorostyrene, α- Chloro-2,6-dichlorostyrene, α-chloro-2,4-dichlorostyrene, β-chloro-2,6-dichlorostyrene, β-chloro-2,4-dichlorostyrene, o-, m- or p- t-butylstyrene, o-, m- or p-methoxystyrene, o-, m- or p-chloromethylstyrene, o-, m- or p-bromomethylstyrene, styrene derivatives substituted with silyl groups, indene And vinyl naphthalene. Among these, styrene, α-methylstyrene, p-methylstyrene, and a mixture thereof are preferable from the viewpoint of industrial availability and glass transition temperature, and styrene is particularly preferable.

  Both the polymer block (a) mainly composed of isobutylene and the polymer block (b) mainly composed of an aromatic vinyl compound should use mutual monomers as copolymerization components. In addition, other monomer components capable of cationic polymerization can be used. Examples of such monomer components include monomers such as aliphatic olefins, dienes, vinyl ethers, silanes, vinyl carbazole, and acenaphthylene. These can be used alone or in combination of two or more.

  The isobutylene block copolymer of the present invention comprises a polymer block (a) mainly composed of isobutylene and a polymer block (b) mainly composed of an aromatic vinyl compound wherein at least one block is co-polymerized with β-pinene. It is a polymer. In view of low temperature characteristics, it is preferable that copolymerization is performed in the polymer block (b) mainly composed of an aromatic vinyl compound. It is preferable.

  From the viewpoint of adhesiveness, the content of β-pinene is preferably 0.01 to 50% by weight, more preferably 0.5 to 40% by weight, and more preferably 1 to 30% by weight of the isobutylene block copolymer (A). Particularly preferred. If the amount is less than 0.01% by weight, there may be a problem in adhesiveness. If the amount exceeds 50% by weight, the material becomes brittle and may have poor rubber elasticity.

  As long as the isobutylene block copolymer (A) of the present invention is composed of a polymer block (a) mainly composed of isobutylene and a polymer block (b) mainly composed of an aromatic vinyl compound, the structure thereof has Is not particularly limited, and for example, any of block copolymers, diblock copolymers, triblock copolymers, multiblock copolymers, etc. having a linear, branched, or star structure can be selected. It is. Preferred structures include a diblock copolymer composed of (a)-(b) and a triblock copolymer composed of (b)-(a)-(b) from the viewpoint of physical property balance and molding processability. A polymer is mentioned. These may be used alone or in combination of two or more in order to obtain desired physical properties and moldability.

  As for the molecular weight of the isobutylene block copolymer (A), the number average molecular weight in GPC measurement in terms of polystyrene is 110,000 to 500,000, and preferably 130,000 to 300,000. When the number average molecular weight of the isobutylene block copolymer (A) used in the composition of the present invention is lower than 110,000, it is not preferable in that the heat resistance at high temperature is significantly lowered, whereas 500,000. If it exceeds 1, fluidity and workability tend to deteriorate. Furthermore, the weight average molecular weight / number average molecular weight of the isobutylene block copolymer is preferably 1.5 or less from the viewpoint of processing stability.

  The isobutylene block copolymer (A) comprises 60 to 95% by weight of the polymer block (a) mainly composed of isobutylene and 40 to 5% by weight of the polymer block (b) mainly composed of an aromatic vinyl compound. It is preferable to include.

  When the polymer block (a) mainly composed of isobutylene is 60% by weight or less, the flexibility may not be sufficient, which is not preferable. When it is 95% by weight or more, it is easy to handle in terms of manufacturing and processing. This is not preferable because it may be inferior.

  Although there is no restriction | limiting in particular about the manufacturing method of an isobutylene type block copolymer (A), It is preferable to obtain by cationic polymerization and it is more preferable to obtain by living cationic polymerization.

  For living cationic polymerization, see, for example, J. Org. P. Kennedy et al. (Carbobetic Polymerization, John Wiley & Sons, 1982) The description of the synthesis reaction is summarized in the book of Matyjazewski et al. (Cationic Polymerizations, Marcel Dekker, 1996).

The living cationic polymerization can be obtained, for example, by polymerizing a monomer component in the presence of a compound represented by the following general formula (I) which is a polymerization initiator.
R ¹ (CR ² R ³ X) n (I)
Wherein X is a halogen atom, a substituent selected from an alkoxy group having 1 to 6 carbon atoms or an acyloxy group, R ¹ is a monovalent or polyvalent aromatic hydrocarbon group or a monovalent or polyvalent aliphatic hydrocarbon group R ² and R ³ are each a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, and R ² and R ³ may be the same or different, and n represents a natural number of 1 to 6. . ]

The compound represented by the general formula (I) serves as a polymerization initiator and generates a carbon cation in the presence of a Lewis acid or the like, and is considered to be a starting point for cationic polymerization. The following compounds etc. are mentioned as an example of the compound of general formula (I) used by this invention.
(1-Chloro-1-methylethyl) benzene [C ₆ H ₅ C (CH ₃ ) ₂ Cl], 1,4-bis (1-chloro-1-methylethyl) benzene [1,4-Cl (CH ₃ ) ₂ CC ₆ H ₄ C (CH ₃ ) ₂ Cl], 1,3-bis (1-chloro-1-methylethyl) benzene [1,3-Cl (CH ₃ ) ₂ CC ₆ H ₄ C (CH ₃ ) ₂ Cl], 1,3,5-tris (1-chloro-1-methylethyl) benzene [1,3,5- (ClC (CH ₃ ) ₂ ) ₃ C ₆ H ₃ ], 1,3-bis (1-Chloro-1-methylethyl) -5- (tert-butyl) benzene [1,3- (C (CH ₃ ) ₂ Cl) ₂ -5- (C (CH ₃ ) ₃ ) C ₆ H ₃ ]

Of these, 1,4-bis (1-chloro-1-methylethyl) benzene and 1,3,5-tris (1-chloro-1-methylethyl) benzene are particularly preferable.
(1-Chloro-1-methylethyl) benzene is also called cumyl chloride, and bis (1-chloro-1-methylethyl) benzene is bis (α-chloroisopropyl) benzene, bis (2-chloro-). Also called 2-propyl) benzene or dicumyl chloride, tris (1-chloro-1-methylethyl) benzene is tris (α-chloroisopropyl) benzene, tris (2-chloro-2-propyl) benzene or tricumyl. Also called chloride.

In producing the isobutylene block copolymer, a Lewis acid catalyst can be further present. Such Lewis acid may be any one that can be used for cationic polymerization. TiCl ₄ , TiBr ₄ , BCl ₃ , BF ₃ , BF ₃ .OEt ₂ , SnCl ₄ , SnBr ₄ , SbCl ₅ , SbBr ₅ , SbF ₅ , WCl ₆ , TaCl ₅ , VCl ₅ , FeCl ₃ , FeBr ₃ , ZnCl ₂ , ZnBr ₂ , AlCl ₃ , AlBr _3, etc .; metal halides such as Et ₂ AlCl, Me ₂ AlCl, EtAlCl ₂ , MeAlCl ₂ , Et ₂ AlBr Organometallic halides such as Me ₂ AlBr, EtAlBr ₂ , MeAlBr ₂ , Et _1.5 AlCl _1.5 , Me _1.5 AlCl _1.5 , Et _1.5 AlBr _1.5 , and Me _1.5 AlBr _1.5 can be suitably used. Among these, TiCl ₄ , BCl ₃ , and SnCl ₄ are preferable in view of the ability as a catalyst and industrial availability, and TiCl ₄ is particularly preferable in the present invention in terms of a balance between catalytic activity and availability.

  The amount of Lewis acid used is not particularly limited, but can be set in view of the polymerization characteristics or polymerization concentration of the monomer used. Usually, it is 0.01-300 molar equivalent with respect to the compound represented with general formula (I), Preferably it is the range of 0.05-200 molar equivalent.

  In the production of the isobutylene block copolymer, an electron donor component can be allowed to coexist if necessary. This electron donor component is believed to have the effect of stabilizing the growth carbon cation during cationic polymerization, and the addition of an electron donor produces a polymer with a narrow molecular weight distribution and a controlled structure. be able to. The electron donor component that can be used is not particularly limited, and examples thereof include pyridines, amines, amides, sulfoxides, esters, and metal compounds having an oxygen atom bonded to a metal atom.

  As the electron donor component, the number of donors defined as a parameter representing the strength as an electron donor (electron donor) of various compounds is usually 15 to 60. 6-di-t-butylpyridine, 2-t-butylpyridine, 2,4,6-trimethylpyridine, 2,6-dimethylpyridine, 2-methylpyridine, pyridine, diethylamine, trimethylamine, triethylamine, tributylamine, N, N-dimethylaniline, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, dimethyl sulfoxide, diethyl ether, methyl acetate, ethyl acetate, trimethyl phosphate, hexamethyl phosphate triamide, titanium ( III) Methoxide, Titanium (IV) Metoki , Titanium alkoxides such as titanium (IV) isopropoxide, titanium (IV) butoxide; aluminum alkoxides such as aluminum triethoxide and aluminum tributoxide can be used, but 2,6-di-t- Butylpyridine, 2,6-dimethylpyridine, 2-methylpyridine, pyridine, diethylamine, trimethylamine, triethylamine, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, titanium (IV) isopropoxide, titanium ( IV) Butoxide and the like. The number of donors of the above various substances is described in “Donor and Acceptor”, by Goodman, Otsuki, Okada, and Academic Publishing Center (1983). Among these, 2-methylpyridine, which has a remarkable effect of addition, is particularly preferable.

  The electron donor component is usually used in an amount of 0.01 to 50 times mol and preferably 0.1 to 30 times mol for the polymerization initiator.

  The polymerization of the isobutylene-based block copolymer can be carried out in an organic solvent as necessary, and the organic solvent can be used without particular limitation as long as it does not essentially inhibit cationic polymerization. Specifically, halogenated hydrocarbons such as methyl chloride, dichloromethane, chloroform, ethyl chloride, dichloroethane, n-propyl chloride, n-butyl chloride, chlorobenzene; benzene, toluene, xylene, ethylbenzene, propylbenzene, butylbenzene, etc. Alkylbenzenes; linear aliphatic hydrocarbons such as ethane, propane, butane, pentane, hexane, heptane, octane, nonane, decane; 2-methylpropane, 2-methylbutane, 2,3,3-trimethylpentane, 2 Branched aliphatic hydrocarbons such as 1,2,5-trimethylhexane; cycloaliphatic hydrocarbons such as cyclohexane, methylcyclohexane and ethylcyclohexane; paraffin oil obtained by hydrorefining petroleum fractions, etc. .

  These solvents may be used alone or in combination of two or more in consideration of the balance of the polymerization characteristics of the monomers constituting the isobutylene block copolymer and the solubility of the resulting polymer. it can. The amount of the solvent used is determined so that the concentration of the polymer is 1 to 50 wt%, preferably 5 to 35 wt%, in consideration of the viscosity of the resulting polymer solution and the ease of heat removal.

  In carrying out the actual polymerization, the respective components are mixed at a temperature of, for example, −100 ° C. or more and less than 0 ° C. under cooling. In order to balance the energy cost and the stability of polymerization, a particularly preferred temperature range is −30 ° C. to −80 ° C.

<Non-hydrogenated terpene resin (B)>
The non-hydrogenated terpene resin (B) used in the present invention is a polymer containing, as a main component, a terpene monomer represented by α-pinene, β-pinene, limonene and the like. After polymerization using a Lewis acid as a catalyst, the carbon-carbon double bond remaining in the polymer is not hydrogenated.

  As the terpene monomer, α-pinene, β-pinene and limonene are preferable, and β-pinene is more preferable.

  The polymer containing a terpene monomer as a main component is one in which the content of the terpene monomer is 70% by weight or more, preferably 90% or more.

  The non-hydrogenated terpene resin (B) may be a polymer composed of only one type of monomer selected from terpene monomers, or two or more types of terpene monomers. It may be a copolymer comprising a mixture, or at least one monomer selected from the group consisting of at least one terpene monomer and styrene, p-methylstyrene, α-methylstyrene. And a copolymer thereof.

  When the non-hydrogenated terpene resin (B) is a copolymer composed of only two or more monomers selected from α-pinene, β-pinene, and limonene, the weight of each monomer is You may mix and use at a rate. When making a high molecular weight terpene resin (B), it is preferable to increase the use ratio of β-pinene. Specifically, the β-pinene content is preferably 60% by weight or more, more preferably 80% by weight or more, and more preferably 90% by weight or more. The high molecular weight terpene resin (B) can be expected to suppress bleed out from the composition for an inner liner for a pneumatic tire of the present invention, and the effect of the present invention can be maintained over a longer period.

On the other hand, when it is important to increase the mobility of the terpene resin (B) in the composition for the inner liner for a pneumatic tire and to actively bleed out to the interface, the content of α-pinene and limonene Specifically, the total content of α-pinene and limonene is preferably 60% by weight or more, more preferably 80% by weight or more, and 90% by weight or more. More preferred.
In the case of a copolymer with an aromatic monomer, use of styrene is preferable from the viewpoint of availability.

  When a copolymer with an aromatic monomer is used, it is preferably a polymer having an aromatic monomer content of 50% by weight or less, more preferably 30% by weight or less, and 20% by weight. % Or less is more preferable. If the content of the aromatic monomer exceeds 50% by weight, the effects of the present invention may not be easily exhibited.

  As for the molecular weight of the non-hydrogenated terpene resin (B) used in the present invention, the number average molecular weight calculated in terms of polystyrene by GPC is preferably 150 to 30,000, preferably 150 to 10,000. Is more preferable, and it is still more preferable that it is 150-5,000. A non-hydrogenated terpene resin (B) having a number average molecular weight exceeding 30,000 is not preferred because it is difficult to produce with today's technical level and is poor in availability.

  The blending amount of the non-hydrogenated terpene resin (B) is 0.1 to 200 parts by weight with respect to 100 parts by weight of the isobutylene block copolymer (A), but 1 to 100 parts by weight. Is preferred. If the amount of the terpene resin (B) that has not been hydrogenated is less than 0.1 part, it is difficult to obtain the expected effect of the present invention. Since it may become remarkable, it is not preferable.

<Composition>
The composition of the present invention may further contain an ethylene-vinyl alcohol copolymer from the viewpoint of improving gas barrier properties. The ethylene-vinyl alcohol copolymer preferably has an ethylene content of 20 to 70 mol%. If the ethylene content is less than 20 mol%, the moisture barrier property and flexibility may be inferior and the flex resistance may be inferior, and the thermoformability may be inferior. Moreover, when it exceeds 70 mol%, there exists a possibility that gas barrier property may be insufficient. The blending amount of the ethylene-vinyl alcohol copolymer is preferably 1 to 400 parts by weight and more preferably 10 to 400 parts by weight with respect to 100 parts by weight of the isobutylene block copolymer (A). When the blending amount of the ethylene-vinyl alcohol copolymer exceeds 400 parts by weight, the flexibility is lost and the bending fatigue characteristics in the long term may be inferior.

  A crosslinking agent and a crosslinking aid may be further added to the composition of the present invention. Examples of the crosslinking agent include elemental sulfur, tetramethylthiuram disulfide, 4,4-dithiobismorpholine, organic peroxide, phenol formaldehyde resin, and halomethylphenol. Among these, simple sulfur, tetramethylthiuram disulfide, and 4,4-dithiobismorpholine are preferable. Examples of the crosslinking aid include metal oxides such as sulfenamide, benzothiazole, guanidine, dithiocarbamic acid, zinc oxide, fatty acids such as stearic acid, nitrogen-containing compounds, triallyl isocyanurate, ethylene glycol dimethacrylate, trimethylolpropane methacrylate. Is mentioned. Among these, preferred are metal oxides such as sulfenamide, benzothiazole, guanidine, dithiocarbamic acid and zinc oxide, and fatty acids such as stearic acid. As a compounding quantity of a crosslinking agent and a crosslinking adjuvant, it is preferable that it is 0.5-5 weight part with respect to 100 weight part of isobutylene type block copolymers (A), respectively.

  The composition of the present invention may further contain a tackifier from the viewpoint of adhesion to carcass rubber. Examples of the tackifier include natural rosin, a terpene phenol resin having a hydroxyl value (OH value) of 50 mgKOH / g or less, a synthetic coumarone indene resin, a petroleum resin, and an alkylphenol resin. The blending amount of the tackifier is preferably 1 to 80 parts by weight with respect to 100 parts by weight of the isobutylene block copolymer (A).

  The composition of the present invention may further contain a filler, an anti-aging agent, a softening agent, and a processing aid depending on the purpose. For example, fillers include carbon black, wet silica, dry silica, calcium carbonate, kaolin, talc, clay, etc. Antiaging agents include antioxidants, ultraviolet absorbers, light stabilizers, softeners Include paraffinic oil, naphthenic oil, aroma oil, rapeseed oil, dioctyl phthalate, dioctyl adipate, etc., and processing aids include higher fatty acids, fatty acid esters, fatty acid metal salts, fatty acid amides, paraffin wax, fatty alcohols , Fluorine / silicone resin, and high molecular weight polyethylene.

  In order to obtain a composition comprising the composition of the present invention, a known melt-kneading method can be applied. For example, an isobutylene block copolymer, an ethylene-vinyl alcohol copolymer, and other components blended to obtain a predetermined physical property are mixed with a heating kneader, for example, a single screw extruder, a twin screw extruder, a roll, a banbury. It can be produced by melt-kneading using a mixer, Brabender, kneader, high shear mixer or the like. The temperature for melt kneading is preferably 100 to 240 ° C. When the temperature is lower than 100 ° C., the isobutylene block copolymer and the ethylene-vinyl alcohol copolymer are not sufficiently melted, and the kneading tends to be uneven. When the temperature is higher than 240 ° C., thermal decomposition and thermal crosslinking of the isobutylene block copolymer and the ethylene-vinyl alcohol copolymer tend to occur. What is necessary is just to film-form the obtained composition by the normal method of film-forming thermoplastic resin and thermoplastic elastomer, such as extrusion molding and calendar molding.

<Application>
The composition of the present invention can be suitably used for an inner liner, particularly a tire inner liner.

  The thickness of the inner liner of the present invention is preferably in the range of 20 μm to 1500 μm in total. When the thickness is less than 20 μm, the bending resistance of the inner liner is lowered, and there is a risk of breakage or cracking due to bending deformation at the time of tire rolling. On the other hand, when the thickness exceeds 1500 μm, the merit of reducing the tire weight is reduced.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these Examples. Prior to the examples, various measurement methods, evaluation methods, and examples will be described.
(Molecular weight measurement)
In the following examples, “number average molecular weight”, “weight average molecular weight” and “molecular weight distribution (ratio of weight average molecular weight to number average molecular weight)” are determined by a standard polystyrene conversion method using gel permeation chromatography (GPC). Calculated. However, LC Module 1 manufactured by Waters was used as the GPC system, polystyrene cross-linked gel was packed as the GPC column (stationary phase) (Shodex GPC K-804; manufactured by Showa Denko KK), and chloroform was used as the moving layer.

(Tensile modulus)
In accordance with JIS K 6251, a test piece obtained by punching a sheet into No. 7 with a dumbbell was prepared and used for measurement. The tensile speed was 100 mm / min. The elastic modulus represents the stress when the strain is 100%.

(Tensile strength)
In accordance with JIS K 6251, a test piece obtained by punching a sheet into No. 7 with a dumbbell was prepared and used for measurement. The tensile speed was 100 mm / min.

(Tensile elongation)
In accordance with JIS K 6251, a test piece obtained by punching a sheet into No. 7 with a dumbbell was prepared and used for measurement. The tensile speed was 100 mm / min.

(Heat-resistant)
In the mixing ratio shown in Table 1, the isobutylene block copolymer (A) -1, (A) -2 or (A) -3, an anti-aging agent (“AO-50” manufactured by Adeka Corporation), Terpene resin (B) -1 or (B) -2 was mixed and kneaded at 170 ° C. using a twin screw extruder to obtain pellets. The obtained pellets were compression molded at 180 ° C. to prepare a 2 mm thick sheet, and two 5 mm × 6 mm test pieces were cut out. According to JIS K-6394, dynamic viscoelasticity was measured while increasing the temperature at a rate of 4 ° C./min in the range of −50 ° C. to 150 ° C. in a shear mode, a frequency of 10 Hz, and a strain of 0.05%. The ratio of the storage elastic modulus G ′ (Pa) at 23 degrees and 200 degrees was used as an index.

(Adhesiveness)
The adhesion with isoprene rubber was evaluated. After bonding with a 2 mm thick unvulcanized sheet of isoprene rubber of (Production Example 1), heating and pressure vulcanization at 150 ° C. and 50 MPa for 40 minutes, and then cutting out to a width of 2 cm × 6 cm, a 180 ° peel test was performed. The stress during the run was measured. The test speed was 200 mm / min, and an average value of stress of 3 cm to 5 cm was adopted after the start of peeling.

(Production Example 1) Production of isoprene rubber sheet 1 L kneader (Molyama Co., Ltd.) in which 400 g of isoprene rubber (trade name “IR2200” manufactured by JSR Corporation) and 200 g of carbon black (Asahi Carbon Asahi # 50) were set at 40 ° C. And then kneaded for 5 minutes at 50 rpm, 6 g of sulfur, 8 g of N-tert-butyl-2-benzothiazolsulfenamide, 8 g of zinc oxide and 8 g of stearic acid were added, kneaded for 2 minutes and then discharged. The sheet was formed into a sheet having a thickness of 2 mm at 80 ° C. with a heating press (manufactured by Shinto Metal Co., Ltd.).

(Production Example 2) Hydrogenated Terpene Resin 20 parts by weight of YS resin PX1105N and 3 parts by weight of 5% palladium / carbon were placed in an autoclave, and nitrogen substitution was performed. 50 parts by weight of cyclohexane was added, and the system was replaced with hydrogen. The system was kept at 100 degrees for 24 hours and then cooled to room temperature.
After removing the precipitate by filtration, the solvent was distilled off under reduced pressure to obtain 20 parts by weight of a hydrogenated terpene resin. From the ¹ H-NMR spectrum of the product, it was confirmed that the peak derived from the vinyl proton of poly (β-pinene) observed in the vicinity of 5.3 ppm disappeared, and that the hydrogenation was in progress. confirmed.

(Production Example 3) [Production of poly (styrene-co-β-pinene) -polyisobutylene-poly (styrene-co-β-pinene) block copolymer (block copolymer 1)]
After the inside of the polymerization vessel of the 5 L separable flask was purged with nitrogen, 450 mL of n-hexane (dried with molecular sieves) and 1800 mL of butyl chloride (dried with molecular sieves) were added using a syringe. After cooling to −70 ° C., 408 mL (4.32 mol) of isobutylene monomer, 0.3297 g (0.00143 mol) of p-dicumyl chloride and 3.9879 g (0.0428 mol) of α-picoline were added. Next, 12.5 mL (0.114 mol) of titanium tetrachloride was added to initiate polymerization. Stirring was continued at −70 ° C. for 2.0 hours from the start of polymerization, and then 67.3 ml (0.585 mol) of a styrene monomer that had been cooled to −70 ° C. in advance was added. After 90 minutes had passed since the addition of styrene, 17.4 ml (0.111 mol) of β-pinene was added. Thereafter, stirring was continued for 15 minutes, and then 6.2 mL (0.057 mol) of titanium tetrachloride was added. Thereafter, stirring was continued at -70 degrees for 30 minutes, and then about 200 mL of methanol was added. After distilling off the solvent from the reaction solution, it was dissolved in toluene and washed twice with water. Further, the toluene solution was added to a large amount of methanol to precipitate a polymer, and the obtained polymer was vacuum-dried at 60 ° C. for 24 hours to obtain the desired [Block Copolymer 1]. The molecular weight of the polymer obtained by gel permeation chromatography (GPC) was measured in terms of polystyrene. Mw was 205,000, Mn 182,000 was Mw / Mn was 1.12.

(Production Example 4) [Production of poly (styrene-co-β-pinene) -polyisobutylene-poly (styrene-co-β-pinene) block copolymer (block copolymer 2)]
After the inside of the polymerization vessel of the 3 L separable flask was purged with nitrogen, 360 mL of n-hexane (dried with molecular sieves) and 1440 mL of butyl chloride (dried with molecular sieves) were added using a syringe. After cooling to −70 ° C., 376 mL (3.97 mol) of isobutylene monomer, 0.430 g (0.00185 mol) of p-dicumyl chloride and 5.201 g (0.0600 mol) of α-picoline were added. Next, 12.3 mL (0.112 mol) of titanium tetrachloride was added to initiate polymerization. Stirring was continued at −70 ° C. for 1.3 hours from the start of polymerization, and then 88 ml (0.7625 mol) of styrene monomer that had been cooled to −70 ° C. in advance was added. After 110 minutes had passed since the addition of styrene, 22.7 ml (0.145 mol) of β-pinene was added. Then, after stirring for 15 minutes, 2.0 mL (0.0182 mol) of titanium tetrachloride was added. Thereafter, stirring was continued at -70 degrees for 30 minutes, and then about 200 mL of methanol was added. After distilling off the solvent from the reaction solution, it was dissolved in toluene and washed twice with water. Further, the toluene solution was added to a large amount of methanol to precipitate a polymer, and the obtained polymer was vacuum-dried at 60 ° C. for 24 hours to obtain the desired [Block Copolymer 2]. The molecular weight of the polymer obtained by gel permeation chromatography (GPC) was measured in terms of polystyrene. Mw was 196,000, Mn was 176,000, and Mw / Mn was 1.11.

(Production Example 5) [Production of poly (styrene-co-β-pinene) -polyisobutylene-poly (styrene-co-β-pinene) block copolymer (block copolymer 3)]
After replacing the inside of the polymerization vessel of the 5 L separable flask with nitrogen, 320 mL of n-hexane (dried with molecular sieves) and 2878 mL of butyl chloride (dried with molecular sieves) were added using a syringe, and the polymerization vessel was After cooling to −70 ° C., 750 mL (7.942 mol) of isobutylene monomer), 1.473 g (0.0064 mol) of p-dicumyl chloride and 0.802 g (0.00861 mol) of α-picoline were added. Next, 9.4 mL (0.086 mol) of titanium tetrachloride was added to initiate polymerization. Stirring was continued at −70 ° C. for 0.8 hours from the start of polymerization, and then 264 ml (2.294 mol) of styrene monomer which had been cooled to −70 ° C. in advance was added. After 90 minutes had passed since the addition of styrene, 77.8 ml (0.497 mol) of β-pinene was added. Thereafter, stirring was continued for 15 minutes, and then 4 mL (0.036 mol) of titanium tetrachloride was added. Then, after stirring for 30 minutes at -70 degree | times, about 200 mL methanol was added. After distilling off the solvent from the reaction solution, it was dissolved in toluene and washed twice with water. Further, the toluene solution was added to a large amount of methanol to precipitate a polymer, and the obtained polymer was vacuum-dried at 60 ° C. for 24 hours to obtain the desired [Block Copolymer 3]. The molecular weight of the polymer obtained by gel permeation chromatography (GPC) was measured in terms of polystyrene. Mw was 129,000, Mn was 108,000, and Mw / Mn was 1.19.

Example 1
100 parts by weight of [Block Copolymer 1] obtained in Production Example 3, 0.2 part by weight of anti-aging agent (“AO-50” manufactured by Adeka Co., Ltd.), non-hydrogenated terpene resin (B ) Was mixed with 5 parts by weight of “YS Resin PX1150N” manufactured by Yasuhara Chemical, and kneaded at 170 ° C. using a twin screw extruder to obtain pellets. The obtained pellet was attached with a T die (die lip diameter of 2000 μm, width of 200 mm), and the film introduced into a single-screw extruder set at a die temperature of 180 ° C. was taken out with a roll to obtain a film having a thickness of 1000 μm. The obtained film was subjected to tensile tests, dynamic viscoelasticity, and adhesion measurements. The results are shown in the column of Example 1 in Table 1.

(Example 2)
100 parts by weight of [Block Copolymer 1] obtained in Production Example 3, 0.2 part by weight of anti-aging agent (“AO-50” manufactured by Adeka Co., Ltd.), non-hydrogenated terpene resin (B ) To obtain a film having a thickness of 1000 μm in the same manner as in Example 1 except that 15 parts by weight of “YS Resin PX1150N” manufactured by Yasuhara Chemical was used, and the tensile test, dynamic viscoelasticity, and adhesiveness of the obtained film were measured. It was. The results are shown in the column of Example 2 in Table 1.

(Example 3)
100 parts by weight of [Block Copolymer 2] obtained in Production Example 4, 0.2 part by weight of anti-aging agent (“AO-50” manufactured by Adeka Co., Ltd.), non-hydrogenated terpene resin (B ) 15 parts by weight of “YS Resin PX1150N” manufactured by Yasuhara Chemical was mixed and kneaded at 170 ° C. using a twin screw extruder to obtain pellets. The obtained pellet was attached with a T die (die lip diameter of 2000 μm, width of 200 mm), and the film introduced into a single-screw extruder set at a die temperature of 180 ° C. was taken out with a roll to obtain a film having a thickness of 1000 μm. The obtained film was subjected to tensile tests, dynamic viscoelasticity, and adhesion measurements. The results are shown in the column of Example 3 in Table 1.

(Comparative Example 1)
Example 1 was used except that 100 parts by weight of [Block Copolymer 1] obtained in Production Example 3 and 0.2 parts by weight of an anti-aging agent (“AO-50” manufactured by Adeka Co., Ltd.) were used. A film having a thickness of 1000 μm was obtained, and the tensile test, dynamic viscoelasticity, and adhesion of the obtained film were measured. The results are shown in the column of Comparative Example 1 in Table 1.

(Comparative Example 2)
100 parts by weight of [Block Copolymer 1] obtained in Production Example 3, 0.2 parts by weight of an antioxidant (“AO-50” manufactured by Adeka Co., Ltd.), hydrogenated terpene obtained in Production Example 2 A film having a thickness of 1000 μm was obtained in the same manner as in Example 1 except that 15 parts by weight of the resin was used, and the tensile test, dynamic viscoelasticity, and adhesion of the obtained film were measured. The results are shown in the column of Comparative Example 2 in Table 1.
(Comparative Example 3)
100 parts by weight of [Block Copolymer 3] obtained in Production Example 5 and 0.2 parts by weight of an anti-aging agent (“AO-50” manufactured by Adeka Co., Ltd.) were mixed, and a twin screw extruder was used. The mixture was kneaded at 170 ° C. to obtain pellets. The obtained pellet was attached with a T die (die lip diameter of 2000 μm, width of 200 mm), and the film introduced into a single-screw extruder set at a die temperature of 180 ° C. was taken out with a roll to obtain a film having a thickness of 1000 μm. The obtained film was subjected to tensile tests, dynamic viscoelasticity, and adhesion measurements. The results are shown in the column of Comparative Example 3 in Table 1.

(Comparative Example 4)
100 parts by weight of [Block Copolymer 3] obtained in Production Example 5, 0.2 part by weight of anti-aging agent (“AO-50” manufactured by Adeka Co., Ltd.), non-hydrogenated terpene resin (B ) 5 parts by weight of “YS Resin PX1150N” manufactured by Yasuhara Chemical was mixed and kneaded at 170 ° C. using a twin screw extruder to obtain pellets. The obtained pellet was attached with a T die (die lip diameter of 2000 μm, width of 200 mm), and the film introduced into a single-screw extruder set at a die temperature of 180 ° C. was taken out with a roll to obtain a film having a thickness of 1000 μm. The obtained film was subjected to tensile tests, dynamic viscoelasticity, and adhesion measurements. The results are shown in the column of Comparative Example 4 in Table 1.

(Comparative Example 5)
100 parts by weight of [Block Copolymer 3] obtained in Production Example 5, 0.2 part by weight of anti-aging agent (“AO-50” manufactured by Adeka Co., Ltd.), non-hydrogenated terpene resin (B ) 15 parts by weight of “YS Resin PX1150N” manufactured by Yasuhara Chemical was mixed and kneaded at 170 ° C. using a twin screw extruder to obtain pellets. The obtained pellet was attached with a T die (die lip diameter of 2000 μm, width of 200 mm), and the film introduced into a single-screw extruder set at a die temperature of 180 ° C. was taken out with a roll to obtain a film having a thickness of 1000 μm. The obtained film was subjected to tensile tests, dynamic viscoelasticity, and adhesion measurements. The results are shown in the column of Comparative Example 5 in Table 1.

Compared with the composition of Comparative Example 1, the compositions shown in Examples 1 to 3 have a good balance between adhesion and heat resistance, and are found to be excellent as a composition for an inner liner for a pneumatic tire. In addition, as shown in Comparative Example 2, it is understood that the effect of improving the adhesiveness cannot be expected when the carbon-carbon double bond in the terpene resin is hydrogenated to form a saturated hydrocarbon skeleton.
Furthermore, as shown in Comparative Examples 3 and 4, when the number average molecular weight of the isobutylene block copolymer (A) is less than 110,000, the storage elastic modulus at a high temperature may be remarkably deteriorated in heat resistance. Recognize.

  From these facts, the composition for an inner liner for a pneumatic tire of the present invention not only has excellent adhesion to the carcass rubber required for the inner liner, but also has excellent heat resistance required in the tire manufacturing process. Recognize.

Claims (8)

An isobutylene block copolymer comprising a polymer block (a) mainly composed of isobutylene and a polymer block (b) mainly composed of an aromatic vinyl compound, wherein at least one of (a) and (b) One block is a copolymer with β-pinene, and 100 parts by weight of an isobutylene block copolymer (A) having a number average molecular weight of 110,000 to 500,000, and a non-hydrogenated terpene resin ( B) The composition for inner liners for pneumatic tires containing 0.1-200 weight part. The inner liner for a pneumatic tire according to claim 1, wherein the isobutylene block copolymer (A) is obtained by copolymerizing β-pinene in the polymer block (b) mainly composed of an aromatic vinyl compound. Composition. The composition for an inner liner for a pneumatic tire according to claim 1 or 2, wherein the content of β-pinene in the isobutylene block copolymer (A) is 0.01 to 50% by weight. The block structure of the isobutylene-based block copolymer (A) is a diblock body of (a)-(b) or a triblock body of (b)-(a)-(b). The composition for inner liners for pneumatic tires of any one of Claims 1. The composition for an inner liner for a pneumatic tire according to any one of claims 1 to 4, wherein the molecular weight distribution (weight average molecular weight / number average molecular weight) of the isobutylene block copolymer (A) is 1.5 or less. . The isobutylene block copolymer (A) contains 60 to 95% by weight of the polymer block (a) mainly composed of isobutylene and 5 to 40% by weight of the block (b) mainly composed of an aromatic vinyl compound. Item 6. The composition for an inner liner for a pneumatic tire according to any one of Items 1 to 5. The composition for an inner liner for a pneumatic tire according to any one of claims 1 to 6, wherein the aromatic vinyl compound is styrene. The non-hydrogenated terpene resin (B) is a polymer composed only of a terpene monomer or a copolymer of a terpene monomer and an aromatic monomer, the aromatic monomer The composition for an inner liner for a pneumatic tire according to any one of claims 1 to 7, which is a non-hydrogenated terpene resin which is a polymer having a content of 20% by weight or less.