WO2003054079A1 - Rubber composition, crosslinkable rubber composition and crosslinked rubber - Google Patents

Abstract

A rubber composition comprising (1) a diene rubber, (2) a polypropylene resin, and (3) a block copolymer composed of one or more diene polymer blocks (A) and one or more hydrogenated diene polymer blocks (B) and having a primary structure: (A-B)x, (A-B)x-A, or B-(A-B)x (wherein x is an integer of 1 or above), which is characterized in that the polypropylene resin (2) is contained in an amount of 0.1 to 70 parts by mass per 100 parts by mass of the diene rubber (1) and the block copolymer (3) is contained in an amount of 0.1 to 25 parts by mass per 100 parts by mass of the total of the diene rubber (1) and the polypropylene resin (2). This rubber composition is improved in dispersion properties of a diene rubber and a polyproplylene resin and interfacial adhesion, so that the rubber composition, crosslinkable rubber composition, and crosslinked rubber according to the invention are excellent in mechanical properties and wear resistance.

Description

 Akira Rubber composition, crosslinkable rubber composition

 The present invention relates to a novel rubber composition, a crosslinkable rubber composition, and a crosslinked product obtained by crosslinking the same, which can be suitably used for tire applications, industrial member applications, and the like. Background art

 In the field of rubber materials, in order to improve mechanical properties such as tensile strength, abrasion resistance, and tear strength, and to impart various physical properties such as heat resistance, oil resistance, and conductivity, depending on the intended use,

(a) mixing a rubber with an inorganic filler such as a pump rack (CB) and silica, subjecting the rubber composition to cross-linking as necessary, and using it as a cross-linked rubber composition; ) Organic rubber typified by rayon and nylon fiber, high styrene resin, resin typified by novolak-phenol resin, etc. are mixed with rubber, and the rubber composition is cross-linked as necessary to form a crosslinked rubber composition. (For example, "Polymer ABC Handbook", N.T.S.I.S., published in January 2001, p. 549-9-55) Four ) .

 The rubber composition or crosslinked rubber composition obtained by the above-described method is widely used in tire applications and industrial component applications.However, it is possible to reduce the weight of the rubber composition as a whole, disperse properties when mixing rubber and resin, and improve the interface. There is still room for improvement, such as further improvements in mechanical properties due to improved adhesion, and improved wear resistance.

As a means for solving such a problem, it is suggested to adopt a polypropylene resin having a small specific gravity as one of the resins used as a mixture with rubber. For example, a rubber composition mixed with a polypropylene resin in order to modify rubber used for evening meals is disclosed in Japanese Patent Application Laid-Open Nos. 9-40909 and 10-330504. Disclosed I have.

 However, when attempting to modify a gen-based rubber by mixing it with a polypropylene resin, the miscibility of the polypropylene resin and the gen-based rubber is not always sufficient, and the shape and particle size of the dispersed particles become uneven. In addition to this, there is a problem that the dispersed particle size is not an appropriate particle size in order to improve the mechanical properties, and that the interfacial adhesion between the polypropylene resin and the gen-based rubber is not sufficient.

 Accordingly, an object of the present invention is to provide a novel rubber that can achieve weight reduction and improved miscibility when mixing a rubber and a resin, that is, improved dispersion characteristics and interfacial adhesion, thereby achieving improvements in mechanical properties and abrasion resistance. It is an object of the present invention to provide a composition, a crosslinkable rubber composition and a crosslinked product. The present inventors have conducted intensive studies to achieve the above object, and as a result, when producing a rubber composition by kneading a gen-based rubber and a polypropylene resin, a gen-based polymer block and a hydrogenated gen-based polymer block were used. By adding a block copolymer that is composed and has a specific primary structure, the miscibility between the gen-based rubber and the polypropylene resin is improved, and the dispersion characteristics of the polypropylene resin and the interface between the gen-based rubber and the polypropylene resin are improved. It has been found that the rubber composition, the cross-linkable rubber composition and the cross-linked product having improved mechanical properties such as tensile properties and abrasion properties can be obtained, and the present invention has been completed. Disclosure of the invention

 That is, the present invention

① It is composed of (1) gen-based rubber, (2) polypropylene resin, (3) gen-based polymer block A and hydrogenated gen-based polymer block B, and

(A-B) _x , (A-B) _x -A, B-(A-B) _x

 (In the formula, X represents an integer of 1 or more.)

A block copolymer having a primary structure of any of the following (hereinafter, may be abbreviated as block copolymer (3)), and a rubber composition comprising: (1) 100 parts by mass of polypropylene resin (2) in an amount of 0.1 to 70 parts by mass, and 100 parts by mass of gen-based rubber (1) and polypropylene resin (2) in total A rubber composition characterized by containing 0.1 to 25 parts by mass of the block copolymer (3);

 (2) a crosslinkable rubber composition comprising the rubber composition described in (1) and a crosslinking agent;

 (3) A crosslinked product obtained by crosslinking the crosslinkable rubber composition described in (1). BEST MODE FOR CARRYING OUT THE INVENTION

 In the present specification, the term “gen-based rubber” means a polymer having a rubber-like property and mainly comprising a conjugated diene compound such as butadiene and isoprene. Examples of the gen-based rubber (1) include natural rubber (NR), polyisoprene rubber (IR), polybutadiene rubber (BR), and styrene-butadiene copolymer rubber (SBR).

 Further, in the present specification, the “polypropylene resin” is mainly a propylene homopolymer or at least one of α-olefins such as ethylene, 1-butene, 1-octene, isobutylene, and 4-methyl-11-pentene. It is a copolymer obtained by copolymerizing with one or more monomers. Among these, propylene homopolymer, propylene monoolefin block copolymer, and propylene-α-olefin random copolymer can be preferably used. One of these may be used alone, or a mixture of two or more may be used. The block copolymer (3) used in the present invention is composed of a gen-based polymer block Α and a hydrogenated gen-based polymer block B, and

(A- B) _x , (A-B) _x -A, B-(A- B) _x

 (Wherein, X represents an integer of 1 or more.,)

Is a block copolymer having any of the following primary structures. Among the two types of blocks constituting the block copolymer (3), the gen-based polymer block A has excellent compatibility with the gen-based rubber (1), such as butadiene and isoprene. This is a polymer block mainly composed of the above conjugated diene compound, and may contain other polymerizable compounds such as a vinyl aromatic compound such as styrene. Examples of the gen-based polymer block A include polyisoprene, polybutadiene, butadiene-isoprene random copolymer, styrenebutadiene random copolymer, and styrene-isoprene random copolymer.

 On the other hand, the hydrogenated gen-based polymer block B has excellent compatibility with the polypropylene resin (2), and is mainly composed of conjugated diene compounds such as butadiene and isoprene, and is composed of vinyl such as styrene. A polymer block obtained by hydrogenating a polymer block which may contain another polymerizable compound such as an aromatic compound. Examples of the hydrogenated gen-based polymer block B include hydrogenated polybutadiene, hydrogenated polyisoprene, hydrogenated styrene-butadiene random copolymer, hydrogenated butadiene-isoprene random copolymer, and the like. Types of the gen-based polymer block A and the hydrogenated gen-based polymer block B constituting the block copolymer (3), and such compounds when each block contains another polymerizable compound such as styrene. The content of conjugated units and the bonding style of the conjugated gen units (1, 4-bonded unit, 1, 2-bonded unit, 3, 4-bonded unit) and their abundance ratio are determined according to the gen-based rubber (1) and polypropylene used. A suitable block can be appropriately selected from the viewpoint of compatibility according to the type of the resin (2).

For example, when natural rubber (NR) is used as the gen-based rubber (1), polyisoprene, preferably 1 of the total isoprene units, is used as the gen-based polymer block A of the block copolymer (3). , 4-—When using polyisoprene with the amount of the binding unit in the range of 50% or more and 99.5% or less, and using styrene-butadiene copolymer rubber (SBR) as the gen-based rubber (1) The block copolymer (3) A styrene-butadiene random copolymer can be suitably used as the copolymer A.

 On the other hand, the hydrogenated polybutadiene of the block copolymer (3) is hydrogenated polybutadiene, and particularly, the amount of 1,2-bond units in all butadiene units is in the range of 50% or more and 100% or less. Hydrogenated polybutadiene obtained by hydrogenating polybutadiene, hydrogenated polyisoprene, in particular, the sum of the amount of 1,2-bonded units and the amount of 3,4-bonded units in all isoprene units is 50% or more. % Or less can be suitably used.

 In addition, from the viewpoint of not compromising the compatibility with the polypropylene resin (2), the carbon-carbon double bond based on the conjugated gen unit in the hydrogenated gen-based polymer block B of the block copolymer (3) (not The unit having a saturated bond) is preferably at most 40%, more preferably at most 20%, based on all the conjugated gen units constituting the hydrogenated gen-based polymer block B. From the viewpoint of not compromising the compatibility with the gen-based rubber (1), the carbon-carbon double bond (unsaturated bond) based on the conjugated gen unit in the gen-based polymer block A of the block copolymer (3) is considered. Is preferably 50 mol% or more, more preferably 70 mol% or more, based on all conjugated gen units constituting the gen-based polymer block A.

The number average molecular weight (Mn) of the block copolymer (3) used in the present invention is not particularly limited, but is usually preferably in the range of 10,000 to 100,000, and more preferably in the range of 20,000 to 500,000. preferable. The block copolymer (3) used in the present invention has a molecular weight distribution represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) within the range of 1.0 to 1.5. Preferably, there is. Here, the number average molecular weight (Mn) and weight average molecular weight (Mw) are the number average molecular weight and weight average molecular weight in terms of polystyrene measured using gel permeation chromatography (GPC). The block copolymer (3) used in the present invention may have a functional group such as a hydroxyl group, a hydroxyl group, an amino group, or an epoxy group at the main chain terminal or a side chain within a range that does not impair the effects of the present invention. May be provided. Further, the block copolymer (3) used in the present invention has a partial structure derived from a coupling agent such as 1,2-dibromoethane, gallium tetrachloride, tin tetrachloride in the molecular main chain. Is also good.

 The method for synthesizing the block copolymer (3) is not particularly limited. For example, a gen-based polymer block which is a precursor of the gen-based polymer block A and the hydrogenated gen-based polymer block B is used. Can be produced by successive anion polymerization followed by hydrogenation (hydrogenation). Alternatively, it can be produced by separately synthesizing a gen-based polymer block A having a functional group at the terminal and a hydrogenated gen-based polymer block B, and then subjecting the functional groups to a coupling reaction. For example, a gen-based polymer block A having a hydroxyl group at its terminal is subjected to anion polymerization of a conjugated gen compound (and, if necessary, a vinyl aromatic compound such as styrene) by a conventionally known method. It is synthesized by adding ethylene oxide, and on the other hand, a hydrogenated gen-based polymer block B having a terminal hydroxyl group is converted to a conjugated gen compound.

(And, if necessary, biel aromatic compounds such as styrene) by anion polymerization using a conventionally known method, adding ethylene oxide when the anion polymerization is stopped, and then hydrogenating the obtained polymer. And then subjecting them to a force-pulling reaction with disocyanate.

In the case where the anion polymerization method is used to obtain the block copolymer (3), the polymerization temperature should be within a range of from 100 to 110 ° C under an inert gas such as dry argon or nitrogen. The polymerization time is within the range of 0.01 to 200 hours. The polymerization initiator is an alkali metal such as sodium metal or lithium metal; an organic alkali such as methyl lithium, ethyl lithium, n-butyl lithium, or s-butyl lithium. Using a metal compound or the like as an initiator, a gen-based polymer block that is a precursor of the gen-based polymer block A and a hydrogenated gen-based polymer block B is formed, respectively. The reaction can be carried out by a method of successively adding a conjugated diene compound (and, if necessary, a vinyl aromatic compound such as styrene) for anionic polymerization. In this method, one or more solvents selected from solvents that can be used in ordinary anion polymerization, for example, hexane, cyclohexane, benzene, and toluene, can be appropriately used.

 In addition, in a series of anion polymerization for forming a gen-based polymer block that is a precursor of the gen-based polymer block A and the hydrogenated gen-based polymer block B, a butadiene unit and an isoprene unit are used. In order to control the ratio of the bonding mode (1,2-linking unit, 1,4-linking unit, 3,4-linking unit, etc.), before or during polymerization, Jethyl ether, tetrahydrofuran, ethylenedali Additives such as ethers such as coal getyl ether; 1, amines such as lyethylamine, N, N, N,, N'-tetramethylethylenediamine may be added.

 Next, the gen-based polymer obtained by the above-described anion polymerization is subjected to a hydrogenation reaction to form a hydrogenated gen-based polymer block B, thereby obtaining a block copolymer (3). The hydrogenation reaction is carried out according to a known method. A supported catalyst comprising a metal such as Pt, Pd, Ru, Rh, and Ni supported on a carrier such as carbon, alumina, or diatomaceous earth; Raney nickel; A catalyst based on a combination of a metal compound and an organic aluminum compound or an organic lithium compound; a bis (cyclopentagenenyl) compound of a transition metal such as zirconium or hafnium with lithium, sodium, potassium, or aluminum In the presence of a hydrogenation catalyst such as a meta-acene catalyst comprising a combination of an organometallic compound such as zinc or magnesium, and the like, in a solvent inert to a hydrogenation reaction such as hexane or cyclohexane, This can be achieved by catalytic hydrogenation of the system polymer.

As described above, the gen-based polymer block A and the hydrogenated gen-based polymer block In the case of hydrogenation after the sequential synthesis of the gen-based polymer block which is the precursor of the quenched B, while suppressing the hydrogenation of the gen-based polymer block A, Amines such as triethylamine, N, N, N ,, N'-tetramethylethylenediamine to promote the hydrogenation reaction of the gen-based polymer block that is It is possible to carry out hydrogenation by adding ethers such as tetrahydrofuran and the like.

 Although the content of each block in the block copolymer (3) used in the present invention is not particularly limited, the effect of improving the dispersion characteristics of the polypropylene resin (2) and the effect of improving the adhesiveness at the interface with the rubber phase are improved. From the viewpoint, the content of the gen-based polymer block A (the sum of a plurality of gen-based polymer blocks A when the block copolymer (3) is present in the block copolymer (3)) is in the state before hydrogenation. The content is preferably in the range of 20 to 80% by mass, while the content of the hydrogenated gen-based polymer block B (when a plurality of hydrogenated gen-based polymer blocks B are present in the block copolymer (3)) The sum of them is preferably in the range of 80 to 20% by mass before hydrogenation.

 The reaction pressure, reaction temperature and reaction time of the hydrogenation reaction are not particularly limited, but usually, the hydrogen pressure is in the range of 0.1 to 20 MPa, and the reaction temperature is in the range of 20 to 250 ° C. The reaction time is in the range of 0.1 to 200 hours. The method for obtaining the block copolymer (3) from the obtained reaction mixture after the above hydrogenation reaction is not necessarily limited. For example, the reaction mixture containing the block copolymer may be converted to a poor mixture such as methanol. The block copolymer (3) can be obtained by coagulating by contacting with a solvent, taking out the coagulated material, pre-drying it, and drying it under heating or reduced pressure.

The rubber composition of the present invention contains 0.1 to 70 parts by mass of the polypropylene resin (2) with respect to 100 parts by mass of the gen-based rubber (1), and the gen-based rubber (1) and the polypropylene resin With respect to 100 parts by mass of the total mass of (2), the block copolymer (3) is included in an amount of 0.1 to 25 parts by mass. Preferably, the content of the block copolymer (3) is in the range of 0.5 to 20 parts by mass with respect to 100 parts by mass of the total weight of the gen-based rubber (1) and the polypropylene resin (2), It is more preferably in the range of 1 to 15 parts by mass. When the amount of the block copolymer (3) is less than 0.1 part by mass or more than 25 parts by mass with respect to 100 parts by mass of the total weight of the gen-based rubber (1) and the polypropylene resin (2). In any case, the effect of improving the dispersion characteristics and the effect of improving the adhesion at the interface are poor.

 The blending amount of the polypropylene resin (2) with respect to 100 parts by mass of the gen-based rubber (1) must be in the range of 0.1 to 70 parts by mass, and is preferably in the range of 1 to 65 parts by mass. More preferably, it is in the range of 5 to 45 parts by mass. If the blending amount of the polypropylene resin (2) is less than 0.1 part by mass, the effect of the polypropylene resin (2) to reinforce the gen-based rubber (1) will be poor, and the blending of the polypropylene resin (2) will be poor. When the amount is more than 70 parts by mass, it is difficult for the obtained rubber composition to achieve the object of the present invention.

 The rubber composition of the present invention can be produced by applying a method generally used as a kneading method, wherein a predetermined amount of a gen-based rubber (1), a polypropylene resin (2), and a block copolymer (3) is added. For example, it can be obtained by kneading using a Brabender-1, Banbury mixer, roll kneader or the like.

 Further, to the rubber composition of the present invention, a reinforcing agent usually added for the purpose of reinforcing the rubber composition, for example, carbon black or silicic acid can be further added as long as the characteristics of the compounding composition are not impaired.

Next, the crosslinkable rubber composition of the present invention will be described. As the crosslinking agent that can be contained in such a crosslinkable rubber composition, those usually used for crosslinking rubber can be used without any particular limitation. Examples thereof include sulfur, morpholine disulfide, and alkylphenol disulfide. Sulfur crosslinking agents such as cyclohexanone peroxide, methylacetate peroxyside, tert-butylperoxyisobutyrate Tert-butylbutylbenzoate, benzoylperoxide, lauroylperoxide, dicumylperoxide, ditert-butylpropyloxide, 1,3-bis (tert-butylpropyloxy) Organic peroxide crosslinking agents such as isopropyl) benzene and the like. The amount of the crosslinking agent used is usually 0.05 to 10 parts by mass with respect to 100 parts by mass of the total amount of the gen-based rubber (1), the polypropylene resin (2) and the block copolymer (3). Is preferably in the range of 0.1 to 5 parts by mass.

ェンアミ ド、 N—ォキシジエチレン一 2—ベンゾチアゾ リルスルフェンアミ ドなどのスルフェンアミ ド系促進剤などが挙げられる。 これ らの架橋促進剤は 2種以上を組み合わせて使用してもよい。 In the present invention, a crosslinking accelerator or a crosslinking aid may be added as necessary. The crosslinking accelerator and the crosslinking assistant are not particularly limited, and can be appropriately selected and used according to the crosslinking agent used. Examples of the crosslinking accelerator include thiuram-based accelerators such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, and tetraethylthiuram disulfide; thiazole-based accelerators such as 2-mercaptobenzothiazol and dibed; N—cyclohexyl—2

Sulfenamide accelerators such as phenamide and N-oxydiethylene-12-benzothiazolylsulfenamide. These crosslinking accelerators may be used in combination of two or more.

 Examples of the crosslinking aid include metal oxides such as zinc oxide and magnesium oxide; metal hydroxides such as calcium hydroxide; metal carbonates such as zinc carbonate and basic zinc carbonate; fatty acids such as stearic acid and oleic acid. Metal salts of fatty acids such as zinc stearate and magnesium stearate; ethylene dimethacrylate, diaryl phthalate, N, N-m-phenylene dimaleide, triallyl isocyanurate, trimethylolpropane trimethacrylate And the like. These crosslinking aids may be used in combination of two or more.

The crosslinkable rubber composition of the present invention may further contain various additives such as an aging inhibitor, a filler, a plasticizer, and a softener, as long as the performance is not impaired. The crosslinkable rubber composition of the present invention employs a method generally used as a kneading method. A cross-linking agent, and if necessary, a cross-linking agent, a cross-linking accelerator, a cross-linking auxiliary agent, etc. for a predetermined amount of the gen-based rubber (1), the polypropylene resin (2), It is obtained by adding. In addition, a crosslinked product can be obtained by, for example, crosslinking with a press molding machine or crosslinking with a mold using such a crosslinkable rubber composition.

 ADVANTAGE OF THE INVENTION The rubber composition of this invention is excellent in miscibility, ie, the dispersion characteristic of a polypropylene resin, and the adhesiveness of the interface of a gen-type rubber and a polypropylene resin is improved. Further, a crosslinkable agent is added to the rubber composition of the present invention to form a crosslinkable rubber composition. Further, by cross-linking such a composition, a bridge having improved mechanical properties such as tensile properties and abrasion resistance has been improved. Therefore, it can be suitably used for applications such as tires, industrial belts, and industrial rubber hoses such as industrial rubber hoses.

 Hereinafter, the present invention will be described specifically with reference to Examples. The present invention is not limited by these examples. Reference example 1

 Into a 5-liter autoclave with nitrogen replacement, 480 g of degassed and dehydrated cyclohexane and 8 m 1 of a 10% by mass cyclohexane solution of s-butyllithium were charged. After that, the temperature was raised to 50, and 410 g of isoprene was added, and polymerization was carried out for 3 hours. A part of the reaction solution was sampled, and the product was analyzed by gel permeation chromatography (GPC). As a result, polystyrene (PSt) -converted Mn = 930,000 and Mw / Mn = 1. It was found that 15 polyisoprene was formed.

Subsequently, degassed and dehydrated N, N, Ν ', Ν'-tetramethylethylenediamine> 3 was added to the above reaction solution, and then 600 g of butadiene was added, followed by polymerization at 50 ° C for 3 hours. Was done. After adding 10 g of methanol to the polymerization solution and performing a polymerization termination reaction, a part of the reaction solution was sampled and analyzed by GPC. It was found that a polyisoprene-polybutadiene block copolymer having Mn = 1780 0 0 and Mw / Mn = 1.16 in terms of t was obtained.

 A hydrogenation catalyst consisting of nickel octylate and triisobutylaluminum was added to the reaction solution obtained above, the temperature was raised to 70 ° C, and hydrogen was supplied into the system until the pressure reached 1 MPa. A hydrogenation reaction was carried out until the iodine value reached 170 below. After the reaction, the reaction solution was poured into 23700 g of methanol to coagulate the polymer. The coagulated product was recovered by filtration, and further dried under reduced pressure at 80 ×: for 12 hours to obtain 1,050 g of the product.

When the obtained product was analyzed by GPC and ¹ H-NMR, 96% of the carbon-carbon double bonds (unsaturated bonds) contained in the polybutadiene block were converted to saturated bonds by hydrogenation. It was confirmed that 80% of the carbon-carbon double bonds (unsaturated bonds) contained in the polyisoprene block remained without hydrogenation. When analyzed by GPC, a diblock polymer of polyisoprene-hydrogenated polybutadiene having a Mn of 1 77300 and a Mw / Mn of 1.515 in terms of PSt (hereinafter referred to as a diblock copolymer) was obtained. The polymer was abbreviated as IR-EB). Example 1

Natural rubber (NR; RSS # 1, ribbed smoked sheet), polypropylene resin (PP; Grand Polymer Co., trade name: Grand Polypro J104W) and IR obtained by the method of Reference Example 1 EB was kneaded with the composition shown in Table 1 at 180, 100 rpm for 7 minutes using a Brabender to obtain a rubber composition. A part of the obtained rubber composition is cut with a freezing mouth tome, dyed with osmium tetroxide (only the natural rubber part is dyed), and then observed with a scanning electron microscope (SEM) to disperse the PP. And photographed. From the analysis of the photograph, the minimum particle diameter and the maximum particle diameter of the dispersed particles were determined, the distribution state of the dispersed particle diameter was examined, and the average dispersed particle diameter was determined. Table 1 shows the results. Comparative Example 1

 A rubber composition consisting of only NR and PP without adding IR-EB was prepared in the same manner as in Example 1, and SEM observation was performed in the same manner as in Example 1. The results are shown in Table 1.

 2) P P: GrandPolypro J104W manufactured by GrandPolymer

As a result of SEM observation, the average dispersed particle diameter of the polypropylene resin was 3 m in Comparative Example 1 and the average dispersed particle diameter was 5 m in the dispersion particle diameter distribution of 3 to 8πι, whereas in Example 1, the dispersed particle diameter was The distribution is 1-3 / xm and the average dispersed particle size is 2 ηι. By adding IR-—, the dispersed particle size is made uniform and the average dispersed particle size is reduced. Was completed. Example 2

NR (RS S # 1, ribbed smoked sheet), PP (manufactured by Grand Polymer Co., Ltd., trade name: Grand Polypro J 104W), IR—EB obtained by the method of Reference Example 1, EB, power pump rack, zinc flower And stearic acid were kneaded in a Banbury mixer at a mixing ratio shown in Table 2 at 180 ° C for 10 minutes. Then, sulfur and a cross-linking accelerator [trade name "NOXELLA MSA-G" (N-oxydiethylene-12-benzothiazolylsulfenamide), manufactured by Ouchi Shinko Chemical Co., Ltd. ], An anti-aging agent [trade name "NOCRACK 8100NA"(N-isopropyl-1-N'-phen-2-u-p-phenylenediamine), manufactured by Ouchi Shinko Chemical Co., Ltd.] Mix by open roll in the ratio by volume, and cross-link by pressing at 145 ° A crosslinked rubber sheet having a thickness of 2 mm was obtained.

 The hardness of the obtained crosslinked rubber sheet was measured by a type A durometer overnight in accordance with JIS 6250. On the other hand, a dumbbell-shaped No. 5 test piece was prepared from the obtained vulcanized rubber sheet by punching, and a tensile test was performed in accordance with JIS K6251, and tensile strength and elongation at break were measured. Also, from the obtained vulcanized rubber sheet, an angle-shaped test piece with no notch was prepared by punching in accordance with JISK 6252, and a tear test was performed according to ft according to JISK6252 to determine the tear strength. Was measured. Further, in accordance with JISK 6264, a test piece was prepared by cross-linking the uncrosslinked rubber under the conditions of 1450 ° C and 40 minutes, and a load of 27 Under 0.0 N, an Akron abrasion test was performed to determine the abrasion volume per 100 abrasion wheels. Table 2 shows the results. Comparative Example 2

 A crosslinked rubber was obtained by performing the same operation as in Example 2 except that IR-EB was not added. Table 2 shows the results of the hardness, tensile test, tear strength and Akron abrasion test of the obtained crosslinked rubber.

 From Table 2, when comparing the physical properties of the crosslinked rubber obtained in Example 2 and the crosslinked rubber obtained in Comparative Example 2, in terms of abrasion resistance, the amount of abrasion decreased by 14% at the same hardness. It can be seen that it is superior to the crosslinked rubber obtained in 2.

Four Formulation Example 2 Comparative Example 2

 N R ° 80 80

PP ²⁾ 2 0 20

IR-EB 5-Zinc white 5 5 Stearic acid 33 Sulfur 22 Nocrack 8 10 NA ³ ) 1 1 Noxeller MS A—G ⁴ ) 1.5 5 1.5 Tensile strength (MPa) 23.4 4 6. 2 elongation at break (%) 47 0 45 0 hardness (JISA) 82 82 tear strength (kg / cm) 84. 2 88. 3 Akron abrasion test (cm ^3/1000 times) 0.1 8 0.2 1

1) NR: RS S # 1, ribbed smoked seat

 2) P P: Grand Polypro J 104 W manufactured by Grand Polymer

3) Anti-aging agent

 (Manufactured by Ouchi Shinko Chemical Co., Ltd., N-iso: 7 ° Π-pill-N'-phene :: --Ρ-phenyleneamine)

4) Vulcanization accelerator

 (Ouchi Shinko Kagaku Kogyo Co., Ltd., ォ -Axoxy 'ethylene-2-ene', thiaryl 'rylsulfenamide)

Industrial applicability

 According to the present invention, a rubber composition, a crosslinkable rubber composition, and a crosslinked product having improved miscibility of a gen-based rubber and a polypropylene resin, that is, improved dispersion properties and interfacial adhesion, and excellent mechanical properties and abrasion resistance are provided. can get.

Claims

The scope of the claims 1. It consists of (1) Gen-based rubber, (2) Polypropylene resin, (3) Gen-based polymer block A and hydrogenated J-based polymer block B, and (A— B) _x , (AB) _x -A, B-(A- B) _x  (In the formula, x represents an integer of 1 or more.) A block copolymer having the primary structure of any one of the above, wherein 0.1 to 70 parts by mass of the polypropylene resin (2) is added to 100 parts by mass of the gen-based rubber (1). And a block copolymer (3) having a total mass of 100 parts by mass of the gen-based rubber (1) and the polypropylene resin (2) in an amount of 0.1 to 25 parts by mass. Composition.  2. A crosslinkable rubber composition comprising the rubber composition according to claim 1 and a crosslinking agent.  3. A crosslinked product obtained by crosslinking the crosslinkable rubber composition according to claim 2.