Elastomer composition and molded article

Abstract

To provide an elastomer composition which is excellent in impact resistance under a low temperature condition.SOLUTION: An elastomer composition contains a block copolymer (I) and a cyclic olefin-based resin (II), wherein a mass ratio of (I) to (II) is 1 / 99 to 90 / 10, and the component (I) satisfies conditions (i) to (iii). <Condition (i)>: a content of a vinyl aromatic monomer unit is 1.0-30 mass% with respect to the total amount of the component (I). <Condition (ii)>: a vinyl bond amount of 1.0-55%. <Condition (iii)>: a vinyl hydrogenation ratio of 5.0-55%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an elastomer composition and a molded article. [Background technology]

[0002] Most polyolefins, such as polyethylene and polypropylene, are opaque plastics. This is because most polyolefins are crystalline. Polyolefins have a structure in which crystalline parts are dispersed within amorphous parts, and because the densities of the crystalline and amorphous parts are different, the refractive index of light differs, causing light to scatter, making them opaque. In addition, because the shrinkage rates of the crystalline and amorphous parts are different, most polyolefins have poor dimensional stability. On the other hand, cyclic olefin resins have an alicyclic structure, which is a bulky structure with large steric hindrance, and therefore are less likely to crystallize, and are excellent in transparency and dimensional stability.

[0003] The cyclic olefin resin has a bulky structure with large steric hindrance, which makes the molecular chains rigid and restricts their movement, resulting in a high glass transition temperature and high heat resistance. Furthermore, since cyclic olefin resins contain almost no polar groups or double bonds, they are virtually free from deformation due to moisture absorption, alteration due to acids or bases, and degradation due to light or heat.Furthermore, the above properties can be further improved by adding hydrogen to the double bonds generated in the polymerization process.

[0004] Cyclic olefin resins having the above-described characteristic structure have been attracting attention in a wide range of fields, such as optical components, pharmaceutical containers, and electronics applications, due to their excellent transparency, low birefringence, high heat resistance, low moisture absorption, gas barrier properties, chemical resistance, and hygiene.

[0005] However, because cyclic olefin resins have a glass transition temperature (Tg) much higher than room temperature, they are hard and brittle materials in a glassy state near room temperature. Therefore, if sufficient breaking strength and impact resistance can be imparted, it is expected that the temperature range in which they can be used will be expanded. In particular, there is a growing need for improved impact resistance, not only for use at room temperature but also for use under low-temperature conditions, in view of the expansion of use areas, such as parts for refrigeration equipment, pharmaceuticals that must be stored under low-temperature conditions, and so on.

[0006] From the above-mentioned viewpoint, a technique has been disclosed relating to a cyclic olefin resin composition in which a thermoplastic elastomer is added to a cyclic olefin resin to improve impact resistance (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 4951883 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the cyclic olefin resin composition disclosed in Patent Document 1 has a problem in that the impact resistance is still insufficient under low-temperature conditions of −30° C. or less, and there is room for improvement.

[0009] In order to improve impact resistance under low-temperature conditions, it is preferable that the glass transition temperature of the thermoplastic elastomer modifier is lower than the use temperature, that is, that the thermoplastic elastomer has low rigidity even under low-temperature conditions. However, the thermoplastic elastomer added to the cyclic olefin resin composition disclosed in Patent Document 1 has a high content of aromatic vinyl monomer units, high rigidity, and a high hydrogenation rate, and therefore has a high glass transition temperature, leaving room for further improvement in impact resistance under low-temperature conditions.

[0010] In view of the above-mentioned problems of the prior art, an object of the present invention is to provide an elastomer composition having excellent impact resistance even under low temperature conditions. [Means for solving the problem]

[0011] As a result of intensive research conducted by the present inventors to solve the problems of the conventional techniques, they found that the problems of the conventional techniques can be solved by adding a block copolymer having a specific structure and physical properties to a cyclic olefin resin, and thus completed the present invention. That is, the present invention is as follows.

[0012] [1] Component (I): a block copolymer (I) having a polymer block (A) mainly composed of vinyl aromatic monomer units and a polymer block (B) mainly composed of conjugated diene monomer units; Component (II): a cyclic olefin resin; Contains the mass ratio of the component (I) to the component (II) is component (I) / component (II)=1 / 99 to 90 / 10; The elastomer composition, wherein the component (I) satisfies the following conditions (i) to (iii): <Condition (i)>: The content of the vinyl aromatic monomer unit is 1.0 to 30% by mass based on the total amount of the component (I). <Condition (ii)>: The polymer block (B) contains units (a) derived from a 1,2-bond and / or a 3,4-bond and units (b) derived from a 1,4-bond, and the content of the units (a) is 1.0 to 55% of the total amount of the polymer block (B). <Condition (iii)>: The polymer block (B) contains hydrogenated alkenyl monomer units (a1) of the units (a) derived from the 1,2-bond and / or the 3,4-bond, and hydrogenated alkenyl monomer units (b1) of the units (b) derived from the 1,4-bond, and the total content of the alkenyl monomer units (a1) and the alkenyl monomer units (b1) is 5.0 to 55% of the total amount of the polymer block (B). [2] The elastomer composition according to [1] above, wherein the component (I) further satisfies the following condition (iv): <Condition (iv)>: The content of hydrogenated alkenyl monomer units (a1) in the units (a) derived from a 1,2-bond and / or a 3,4-bond is 80% or more based on the total amount of the units (a) derived from a 1,2-bond and / or a 3,4-bond. [3] A molded article of the elastomer composition according to [1] or [2] above. [Effects of the Invention]

[0013] According to the present invention, an elastomer composition having excellent impact resistance even under low temperature conditions can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. It should be noted that the following embodiments are merely examples for explaining the present invention, and are not intended to limit the present invention to the following content, and the present invention can be implemented in various modified forms within the scope of its gist.

[0015] [Elastomer composition] The elastomer composition of the present embodiment is The composition includes a block copolymer (hereinafter also referred to as "block copolymer (I)" or "component (I)") having a polymer block (hereinafter also referred to as "polymer block (A)") mainly composed of vinyl aromatic monomer units and a polymer block (hereinafter also referred to as "polymer block (B)") mainly composed of conjugated diene monomer units, and a cyclic olefin resin other than component (I) (hereinafter also referred to as "cyclic olefin resin (II)" or "component (II)"). The mass ratio of the component (I) to the component (II) (component (I) / component (II)) is 1 / 99 to 90 / 10. In the elastomer composition of the present embodiment, the component (I) satisfies the following conditions (i) to (iii). <Condition (i)>: The content of the vinyl aromatic monomer unit is 1.0 to 30 mass % based on the total amount of component (I). <Condition (ii)>: The polymer block (B) contains units (a) (hereinafter sometimes simply referred to as "units (a)") derived from a 1,2-bond and / or a 3,4-bond, and units (b) (hereinafter sometimes simply referred to as "units (b)") derived from a 1,4-bond, and the content of the units (a) is 1.0 to 55% of the total amount of the polymer block (B). <Condition (iii)>: The polymer block (B) contains a hydrogenated alkenyl monomer unit (a1) (hereinafter, also referred to as "alkenyl monomer unit (a1)") of the unit (a) derived from the 1,2-bond and / or 3,4-bond, and a hydrogenated alkenyl monomer unit (b1) (hereinafter, also referred to as "alkenyl monomer unit (b1)") of the unit (b) derived from the 1,4-bond, and the total content of the alkenyl monomer unit (a1) and the alkenyl monomer unit (b1) is 5.0 to 55% of the total amount of the polymer block (B).

[0016] By having the above-mentioned constitution, an elastomer composition having excellent impact resistance even under low temperature conditions can be obtained.

[0017] (Component (I): Block Copolymer (I)) The elastomer composition of the present embodiment contains a block copolymer (I) having a polymer block (A) mainly composed of vinyl aromatic monomer units and a polymer block (B) mainly composed of conjugated diene monomer units.

[0018] The conjugated diene monomer units are formed by polymerizing a conjugated diene compound. Conjugated diene compounds are diolefins having a pair of conjugated double bonds. Examples of conjugated diene compounds include, but are not limited to, 1,3-butadiene, 2-methyl-1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, etc. Among these, 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred. 1,3-butadiene and isoprene are widely used and easily available, and are advantageous in terms of cost. They are also easily copolymerized with styrene, which is widely used as a vinyl aromatic compound. 1,3-butadiene is also the easiest to adjust the tan δ peak of the block copolymer (I) to a low temperature of -30°C or lower and / or an ultralow temperature of -50°C or lower. When 1,3-butadiene is polymerized, the resulting polymer has a 1,4-bond with a double bond in the main chain, and a 1,2-bond and a 3,4-bond (also called a vinyl bond) with a double bond in the side chain. The glass transition temperature of a block copolymer (I) using 1,3-butadiene as a polymerization monomer depends on the bonding mode of 1,3-butadiene and the hydrogenation of the double bonds remaining in the polymer. Therefore, the tan δ peak of the block copolymer (I) can be controlled by adjusting the bonding mode and the hydrogenation reaction of the double bonds present in the main chain and side chain.

[0019] The conjugated diene compounds may be used singly or in combination of two or more. In this specification, the term "conjugated diene monomer unit" refers to a structural unit derived from a conjugated diene compound in a polymer produced by polymerization of the conjugated diene compound.

[0020] The vinyl aromatic monomer units are formed by polymerizing a vinyl aromatic compound. Vinyl aromatic compounds are aromatic compounds containing vinyl bonds. Examples of vinyl aromatic compounds include, but are not limited to, styrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylethylene, N,N-dimethyl-p-aminoethylstyrene, N,N-diethyl-p-aminoethylstyrene, etc. Among these, styrene is preferred.

[0021] The vinyl aromatic compounds may be used alone or in combination of two or more. In this specification, the term "vinyl aromatic monomer unit" refers to a structural unit derived from a vinyl aromatic compound in a polymer produced by polymerization of the vinyl aromatic compound.

[0022] Component (I) is a block copolymer having a polymer block (A) mainly composed of vinyl aromatic monomer units and a polymer block (B) mainly composed of conjugated diene monomer units, and is a hydrogenated product as it satisfies the condition (iii) described below.

[0023] In this specification, when the polymer block (A) is mainly composed of vinyl aromatic monomer units, the term "mainly composed of" means that the content of vinyl aromatic monomer units is 70 mass% or more relative to the total amount of the polymer block (A). The content of the vinyl aromatic monomer unit in the polymer block (A) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 100% by mass (no other monomers are intentionally added), based on the total amount of the polymer block (A).

[0024] In this specification, when it is stated that the polymer block (B) is mainly composed of conjugated diene monomer units, the term "mainly composed of" means that the content of conjugated diene monomer units is 70 mass% or more relative to the total amount of the polymer block (B). The content of the conjugated diene monomer unit in the polymer block (B) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 100% by mass (no other monomers are intentionally added), based on the total amount of the polymer block (B).

[0025] The content of polymer block (A) in component (I) can be calculated from the following formula using the mass of the vinyl aromatic monomer block component (excluding vinyl aromatic monomer block components having an average degree of polymerization of about 30 or less) obtained, for example, by a method in which a copolymer before hydrogenation is oxidatively decomposed with tert-butyl hydroperoxide using osmium tetroxide as a catalyst (the method described in I. M. Kolthoff, et al., J. Polym. Sci. 1, 429 (1946)). Content (mass%) of polymer block (A)=(mass of vinyl aromatic monomer block component in block copolymer before hydrogenation / mass of block copolymer before hydrogenation)×100

[0026] When component (I) consists only of polymer blocks (A) and (B), the content of polymer block (B) in component (I) can be determined by subtracting the content of polymer block (A) from the total amount of component (I), or by a method similar to the method for determining the content of polymer block (A) described above.

[0027] Component (I) is preferably a block copolymer having a basic skeleton of polymer block (A) and polymer block (B), with these basic skeletons having a repeating structure.

[0028] The component (I) satisfies the following conditions (i) to (iii). <Condition (i)>: The content of the vinyl aromatic monomer unit is 1.0 to 30% by mass based on the total amount of the component (I). By having the content of vinyl aromatic monomer units of 30% by mass or less relative to the total amount of component (I), the elastomer composition of this embodiment becomes rubbery and has low rigidity under low-temperature conditions. Therefore, the elastomer composition has excellent impact resistance under low-temperature conditions. From the viewpoint of further improving the rigidity and impact resistance under low-temperature conditions, the content of the vinyl aromatic monomer units is preferably 28% by mass or less, more preferably 27% by mass or less, even more preferably 25% by mass or less, and even more preferably 23% by mass or less.

[0029] On the other hand, a smaller content of vinyl aromatic monomer units relative to the total amount of component (I) is preferable from the viewpoint of impact resistance under low temperature conditions. However, by having polymer blocks of vinyl aromatic monomer units that serve as pseudo-crosslinking points, it is possible to maintain fatigue recovery properties and tensile strength that are sufficiently good for practical use. From the above viewpoint, the content of the vinyl aromatic monomer unit relative to the total amount of component (I) is 1.0 mass% or more, and from the viewpoint of reducing blocking during storage, preservation, and transportation of the block copolymer (I), the content of the vinyl aromatic monomer unit relative to the total amount of component (I) is 5.0 mass% or more. It is preferably at least 7.0% by mass, more preferably at least 10% by mass.

[0030] The content of the vinyl aromatic monomer unit relative to the total amount of component (I) is preferably 3.0 to 28 mass%, more preferably 5.0 to 27 mass%, even more preferably 7.0 to 25 mass%, and even more preferably 10 to 23 mass%.

[0031] The content of the vinyl aromatic monomer unit in the block copolymer (I) can be controlled within the above-mentioned range by adjusting the polymerization conditions such as the amount of monomer added, the timing of addition, the polymerization temperature, etc. The content of the vinyl aromatic monomer unit in the block copolymer (I) can be calculated by the method described in the Examples.

[0032] <Condition (ii)> The polymer block (B) mainly composed of conjugated diene monomer units contains units (a) derived from 1,2-bonds and / or 3,4-bonds and units (b) derived from 1,4-bonds, and the content of the units (a) is 1.0 to 55% of the total amount of the polymer block (B). By controlling the content of the unit (a) to 55% or less of the total amount of the polymer block (B), the block copolymer (I) can maintain a rubbery state under low-temperature conditions. Furthermore, by containing 1.0% by mass or more of the unit (a) derived from 1,2-bonds and / or 3,4-bonds, which have plastic-like properties, good extrusion processability can be obtained. The content of the unit (a) relative to the total amount of the polymer block (B) is preferably 5.0 to 50%, more preferably 10 to 45%, and even more preferably 15 to 40%.

[0033] The content of the units (a) derived from 1,2-bonds and / or 3,4-bonds relative to the total amount of the polymer block (B) can be controlled by using a regulator such as a polar compound during polymerization of the block copolymer (I), and can be calculated by the method described in the examples below. As the adjuster, for example, a tertiary amine compound or an ether compound can be used, and it is preferable to use a tertiary amine compound. Tertiary amine compounds have the general formula R 1 R 2 R 3 N (wherein, R 1 , R 2 , R 3 is a hydrocarbon group having 1 to 20 carbon atoms or a hydrocarbon group having a tertiary amino group. Examples of tertiary amine compounds include, but are not limited to, trimethylamine, triethylamine, tributylamine, N,N-dimethylaniline, N-ethylpiperidine, N-methylpyrrolidine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetraethylethylenediamine, 1,2-dipiperidinoethane, trimethylaminoethylpiperazine, N,N,N',N",N"-pentamethylethylenetriamine, and N,N'-dioctyl-p-phenylenediamine. The amount of the regulator used during polymerization of the block copolymer (I) is preferably 2 mol or less, more preferably 1.5 mol or less, and even more preferably 1.0 mol or less, per mol of the polymerization initiator described below.

[0034] <Condition (iii)> The polymer block (B) mainly composed of conjugated diene monomer units contains hydrogenated alkenyl monomer units (a1) of units (a) derived from a 1,2-bond and / or a 3,4-bond, and hydrogenated alkenyl monomer units (b1) of units (b) derived from a 1,4-bond, and the total content of the alkenyl monomer units (a1) and the alkenyl monomer units (b1) is 5.0 to 55% of the total amount of the polymer block (B). When the total content of the alkenyl monomer unit (a1) and the alkenyl monomer unit (b1) is 55% or less based on the total amount of the polymer block (B), the main dispersion peak temperature of the tan δ curve of the block copolymer (I) can be set to -35°C or less. Generally, when the content of units (a) derived from 1,2-bonds and / or 3,4-bonds or the total amount of the alkenyl monomer units (a1) and the alkenyl monomer units (b1) relative to the total amount of the polymer block (B) is high, the peak tan δ temperature of the block copolymer (I) tends to be high and the impact resistance at low temperatures tends to be reduced. Therefore, as in the above-mentioned <Condition (ii)>, the content of units (a) derived from 1,2-bonds and / or 3,4-bonds relative to the total amount of the polymer block (B) is set to 55% or less, and as in <Condition (iii)>, the total content of the alkenyl monomer units (a1) and the alkenyl monomer units (b1) relative to the total amount of the polymer block (B) is set to 55% or less. This allows the block copolymer (I) to achieve excellent thermal stability. The total content of the alkenyl monomer unit (a1) and the alkenyl monomer unit (b1) relative to the total amount of the polymer block (B) is preferably 5.0 to 50%, more preferably 10 to 45%, and even more preferably 15 to 40%.

[0035] The total content of the alkenyl monomer unit (a1) and the alkenyl monomer unit (b1) relative to the total amount of the polymer block (B) can be controlled within the above-mentioned numerical range by appropriately adjusting the reaction temperature, reaction time, hydrogen supply amount, catalyst amount, etc. in the hydrogenation step of the block copolymer (I).

[0036] (Modification of elastomer composition with component (II)) In a typical polymer alloy, when impact resistance is imparted by dispersing a specific elastomer in a matrix resin, when the alloy is subjected to impact or stretching, voids are generated in the elastomer phase itself dispersed in the matrix resin, and destruction occurs starting from the elastomer phase. In this case, the lower the rigidity of the elastomer phase relative to the matrix resin, the more stress is concentrated at the interface. Therefore, in order to achieve a high modifying effect even under low-temperature conditions, it is preferable that the elastomer component be more flexible under low-temperature conditions. In other words, in order to achieve high impact resistance under low-temperature conditions, the added elastomer must be in a low-rigidity rubber state under those low-temperature conditions. The mechanism by which the above-mentioned physical properties are expressed also applies to elastomer compositions containing components (I) and (II). By dispersing block copolymer (I), which has low rigidity even at low temperatures, in cyclic olefin resin (II), which has a high glass transition temperature and high rigidity, the composition exhibits excellent impact resistance at low temperatures.

[0037] Whether an elastomer is in a rubbery state under certain temperature conditions can be approximately determined by the temperature at which micro-Brownian motion (primary dispersion) of the elastomer's main chain occurs, i.e., the primary dispersion peak temperature of the tan δ curve in the viscoelastic spectrum. If the temperature is higher than the primary dispersion peak temperature, the elastomer will be in a rubbery state. The vinyl bond content and hydrogenation rate in an elastomer affect the main dispersion peak temperature of the tan δ curve, and the rigidity under low temperature conditions tends to depend on the content of vinyl aromatic monomer units. Therefore, when designing the structure of an elastomer, it is necessary to set the vinyl bond content, hydrogenation rate, and content of vinyl aromatic monomer units according to the required performance. The main dispersion peak temperature of the tan δ curve can be controlled by adjusting the bonding state and hydrogenation amount of the polymer block (B) mainly composed of conjugated diene monomer units. The main dispersion peak of the tan δ curve in the viscoelasticity spectrum of the block copolymer (I) constituting the elastomer composition of the present embodiment is preferably present at −35° C. or lower, more preferably at −45° C. or lower, and even more preferably at −55° C. or lower. The "main dispersion peak of tan δ" refers to the movement of the main chain in the molecular structure, and refers to the maximum value of the tan δ curve before melting. By showing the maximum temperature at -35°C or below, the material exhibits excellent impact resistance even under low-temperature conditions. The lower limit of the main dispersion peak temperature of tan δ is not particularly limited, and it is preferable that the temperature be at a lower value. The "main dispersion peak temperature of tan δ" can be measured by the method described in the examples below.

[0038] The method for producing the hydrogenated block copolymer (I) is not particularly limited, and any conventionally known method can be applied, such as a method using a hydrogenation catalyst. Examples of hydrogenation catalysts that can be used include: (1) supported heterogeneous catalysts in which a metal such as nickel, platinum, palladium, or ruthenium is supported on carbon, silica, alumina, or diatomaceous earth; (2) so-called Ziegler-type hydrogenation catalysts that use a transition metal salt such as an organic acid salt or acetylacetonate of nickel, cobalt, iron, or chromium, etc., and a reducing agent such as organoaluminum; and (3) homogeneous hydrogenation catalysts such as so-called organometallic complexes of organometallic salt compounds of titanium, ruthenium, rhodium, zirconium, etc. Specific examples of the hydrogenation catalyst that can be used include the hydrogenation catalysts described in Japanese Patent Publication Nos. 42-8704, 43-6636, 63-4841, 1988-37970, 1989-53851, and 2-9041. Preferred hydrogenation catalysts include titanocene compounds and / or reducing organometallic compounds. The titanocene compound may be one described in JP-A-8-109219. Examples of the titanocene compound include compounds having at least one ligand with a (substituted) cyclopentadienyl skeleton, an indenyl skeleton, or a fluorenyl skeleton, such as biscyclopentadienyltitanium dichloride and monopentamethylcyclopentadienyltitanium trichloride. The titanocene compound may contain one of the above skeletons alone or a combination of two of them. Examples of the reducing organometallic compound include organic alkali metal compounds such as organolithium compounds, organomagnesium compounds, organoaluminum compounds, organoboron compounds, and organozinc compounds. These may be used alone or in combination of two or more. As mentioned above, it is important that the block copolymer (I) remains in a rubbery state and has low rigidity under low temperature conditions.

[0039] <Condition (iv)> In the block copolymer (I) of the present embodiment, the content of hydrogenated alkenyl monomer units (a1) of units (a) derived from 1,2-bonds and / or 3,4-bonds in the block (B) (hereinafter also referred to as "vinyl hydrogenation rate") is preferably 80% or more based on the total amount of units (a) derived from 1,2-bonds and / or 3,4-bonds. When the vinyl hydrogenation rate: (a1) / (a) is 80% or more, the block copolymer (I) has a main dispersion peak temperature of the tan δ curve of −55° C. or less, and has improved impact resistance under cryogenic conditions.

[0040] After polymerization, block copolymer (I) is melted and subjected to shear at high temperatures during the desolvation process and during the melt-kneading process with the cyclic olefin resin (II) that constitutes the elastomer composition of this embodiment. Therefore, thermal degradation (side reactions such as molecular scission, crosslinking, and gelation) caused by exposure to these high temperatures can result in increased rigidity and a higher tan δ peak temperature, potentially resulting in insufficient impact resistance at low temperatures. Furthermore, the units (a) derived from 1,2-bonds and / or 3,4-bonds in component (I) contain double bonds in their side chains, which is thought to make them more susceptible to the above-mentioned thermal degradation than the units (b) derived from 1,4-bonds. Therefore, particularly when the elastomer composition of the present embodiment contains a high amount of filler or the like or when melt-kneading and / or molding at a higher temperature than conventional elastomer compositions is required, from the viewpoint of suppressing the increase in rigidity due to the thermal degradation and the increase in the tan δ peak temperature, and from the viewpoint of improving the impact resistance of the elastomer composition of the present embodiment, the vinyl hydrogenation rate (a1) / (a) is preferably 80% or more, more preferably 83% or more, and even more preferably 85% or more. When the total content of the alkenyl units (a1) and (b1) is equal to or less than the content of the units (b) derived from 1,4-bonds, the ratio of the content of the alkenyl units (b1) to the total content, i.e., (b1) / ((a1)+(b1)), is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. This can suppress the increase in rigidity and the increase in the tan δ peak temperature due to the thermal degradation, thereby achieving sufficient impact resistance even at low temperatures and improving the impact resistance of the elastomer composition of this embodiment.

[0041] In order to achieve the vinyl hydrogenation rate (a1) / (a) of 80% or more, it is effective to carry out the hydrogenation reaction of the block copolymer (I) using the hydrogenation catalyst described above, preferably at 55 to 200° C., more preferably at 60 to 170° C., even more preferably at 65 to 160° C., and even more preferably at 70 to 150° C. By setting the hydrogenation temperature to 55° C. or higher, the vinyl hydrogenation rate (a1) / (a) tends to be 80% or higher, while by setting the hydrogenation temperature to 200° C. or lower, the thermal degradation described above is prevented, and the tan δ peak temperature tends to shift to a lower temperature. The pressure of hydrogen used in the hydrogenation reaction is usually 0.1 MPa, preferably 0.2 to 10 MPa, and more preferably 0.3 to 5 MPa. The hydrogenation reaction time is usually 3 minutes to 10 hours, and preferably 10 minutes to 5 hours. The hydrogenation reaction can be a batch process, a continuous process, or any combination thereof.

[0042] <Weight-average molecular weight of block copolymer (I)> The weight average molecular weight of the block copolymer (I) is preferably 5.0×10 3 ~1.0×10 6 and more preferably 1.0 × 10 4 ~5.0×10 5 , and more preferably 3.0 × 10 4 ~3.0×10 5 , and more preferably 5.0 × 10 4 ~2.0×10 5 is. The weight average molecular weight of the block copolymer (I) is 5.0 × 10 3 By setting the weight average molecular weight to 1.0×10 or more, the stickiness of the block copolymer (I) is reduced, which improves handling and suppresses blocking during storage and transportation. 6 When the above condition is satisfied, the molding processability tends to be excellent.

[0043] (Component (II): Cyclic olefin resin) The elastomer composition of the present embodiment contains the above-described block copolymer (I) and a cyclic olefin resin (II). The cyclic olefin resin is a polymer of a cyclic olefin monomer, has a cyclic structure in the side chain, and has amorphous properties such that no melting point is observed when measured by a differential scanning calorimeter (DSC). The higher the content of cyclic olefin monomer units in a cyclic olefin resin, the more amorphous it becomes, and the higher the content of ethylene, a copolymer component, the more likely it is to exhibit crystallinity. The cyclic olefin resin used in this embodiment is a homopolymer of a cyclic olefin monomer, or a cyclic olefin copolymer in which ethylene is copolymerized to such an extent that the melting point is not observable by DSC measurement. In the elastomer composition of the present embodiment, when a commercially available cyclic olefin resin (II) is used, the indication of whether the resin is crystalline or non-crystalline is used depending on the properties of the target elastomer composition. The main chain of the addition homopolymer of a cyclic olefin, the addition copolymer of a cyclic olefin and an α-olefin, and the ring-opening polymer of a cyclic olefin may be partially or entirely hydrogenated.

[0044] Examples of the cyclic olefins used in the production of the cyclic olefin resin (II) include bicyclo(2.2.1)-2-heptene, 5-methylbicyclo(2.2.1)-2-heptene, 5,6-dimethylbicyclo(2.2.1)-2-heptene, tetracyclo(4.4.0.1)-2-heptene, and tetracyclo(4.4.0.1)-2-heptene. 2,5 .1 7,10 )-3-dodecene, 8-methyltetracyclo(4.4.0.1 2,5 .1 7,10 )-3-dodecene, 8,9-dimethyltetracyclo(4.4.0.1 2,5 .1 7,10 )-3-dodecene, etc. Further examples include Diels-Alder adducts of DCPD (dicyclopentadiene) and CPD (cyclopentadiene) with an olefin, etc. These cyclic olefins may be used alone or in combination of two or more.

[0045] When the cyclic olefin resin (II) is an addition copolymer, examples of the copolymerization component used to produce the cyclic olefin resin (II) include α-olefins having 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, and 1-decene. These α-olefins are usually used in an amount of 50 to 90 mol %, preferably 50 to 70 mol %, based on the cyclic olefin. If the amount of α-olefin copolymerized is too large, the resulting addition copolymer may become crystalline.

[0046] When the cyclic olefin resin (II) is a ring-opening polymer, examples of the cyclic olefin used to produce the cyclic olefin resin (II) include, but are not limited to, bicyclo(2.2.1)-2-heptene, 5-methylbicyclo(2.2.1)-2-heptene, 5,6-dimethylbicyclo(2.2.1)-2-heptene, 5-carboxymethylbicyclo(2.2.1)-2-heptene, dicyclopentadiene, 2,3-dihydrodicyclopentadiene, tetracyclo(4.4.0.1), ... 2,5 .1 7,10 )-3-dodecene, 8-methyltetracyclo(4.4.0.1 2,5 .1 7,10 )-3-dodecene, 8-ethyltetracyclo(4.4.0.1 2,5 .1 7,10 )-3-Dodecene, 8-carboxymethyltetracyclo(4.4.0.1 2,5 .1 7,10 )-3-dodecene, 8-methyl-8-carboxymethyltetracyclo(4.4.0.1 2,5 .1 7,10 )-3-dodecene, etc.

[0047] As a method for producing the cyclic olefin resin (II) by addition polymerization, various known methods can be employed. For example, polymerization can be carried out using a Ziegler catalyst or a metallocene catalyst. More specifically, copolymerization components such as cyclic olefin and ethylene are reacted in a hydrocarbon solvent such as cyclohexane using a catalyst in which a soluble vanadium compound, a soluble titanium compound, a soluble zirconium compound, or the like is combined with a cocatalyst such as an organoaluminum compound, typically at a temperature in the range of -50 to 100°C and a pressure in the range of 0 to 50 kg / cm. 2 The polymerization can be carried out in the pressure range of 1000 to 2000 kJ / min.

[0048] The cyclic olefin resin (II) can be produced by ring-opening polymerization using various known methods. For example, a cyclic olefin is subjected to a catalytic reaction in a catalyst system containing a transition metal compound or a platinum group metal compound and an organometallic compound such as an organoaluminum compound, and, if necessary, in the presence of an additive such as an aliphatic or aromatic tertiary amine, usually at a temperature range of −20 to 100° C., usually at a pressure of 0 to 50 kg / cm. 2 The polymerization can be carried out in the pressure range of 100 to 2000. Furthermore, the hydrogenation reaction after the polymerization can also be carried out in the presence of a known hydrogenation catalyst.

[0049] The cyclic olefin resin (II) is preferably an addition copolymer of a cyclic olefin and an α-olefin, or a hydrogenated product thereof.

[0050] The cyclic olefin resin containing a cyclic olefin component as a copolymerization component may be a commercially available general-purpose product. Examples of commercially available cyclic olefin resins include TOPAS (registered trademark) (manufactured by Polyplastics Co., Ltd.), APEL (registered trademark) (manufactured by Mitsui Chemicals, Inc.), ZEONOR (registered trademark) (manufactured by Zeon Corporation), ZEONEX (registered trademark) (manufactured by Zeon Corporation), and ARTON (registered trademark) (manufactured by JSR Corporation).

[0051] The component (II) may be used alone or in combination of two or more.

[0052] In the elastomer composition of the present embodiment, the mass ratio of component (I) to component (II) (component (I) / component (II)) is 1 / 99 to 90 / 10, preferably 10 / 90 to 90 / 10, more preferably 10 / 90 to 70 / 30, and even more preferably 10 / 90 to 50 / 50. When the mass ratio of component (I) / component (II) is 1 / 99 to 90 / 10, an elastomer composition exhibiting impact resistance under low-temperature conditions can be obtained, and when the mass ratio is in the range of 1 / 99 to 30 / 70, a molded article of the elastomer composition of this embodiment can maintain high dimensional stability.

[0053] (Method for producing block copolymer (I)) The block copolymer (I) can be produced, for example, by carrying out living anionic polymerization in a hydrocarbon solvent using a polymerization initiator such as an organic alkali metal compound.

[0054] Examples of hydrocarbon solvents include, but are not limited to, aliphatic hydrocarbons such as n-butane, isobutane, n-pentane, n-hexane, n-heptane, and n-octane; alicyclic hydrocarbons such as cyclohexane, cycloheptane, and methylcycloheptane; and aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene.

[0055] Examples of the polymerization initiator include organic alkali metal compounds such as aliphatic hydrocarbon alkali metal compounds, aromatic hydrocarbon alkali metal compounds, and organic amino alkali metal compounds, which are generally known to have anionic polymerization activity for conjugated diene compounds and vinyl aromatic compounds. Examples of the alkali metal include lithium, sodium, and potassium. Examples of organic alkali metal compounds include, but are not limited to, aliphatic and aromatic hydrocarbon lithium compounds having 1 to 20 carbon atoms, including compounds containing one lithium atom per molecule, dilithium compounds containing multiple lithium atoms per molecule, trilithium compounds, and tetralithium compounds. Specific examples of organic alkali metal compounds include n-propyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, n-pentyllithium, n-hexyllithium, benzyllithium, phenyllithium, tolyllithium, a reaction product of diisopropenylbenzene and sec-butyllithium, and a reaction product of divinylbenzene, sec-butyllithium, and a small amount of 1,3-butadiene. Furthermore, 1-(t-butoxy)propyllithium, as disclosed in U.S. Patent No. 5,708,092, and lithium compounds into which one to several isoprene monomer molecules have been inserted to improve solubility, siloxy-containing alkyllithiums such as 1-(t-butyldimethylsiloxy)hexyllithium, as disclosed in British Patent No. 2,241,239, amino-containing alkyllithiums such as diisopropylamidelithium and hexamethyldisilazidelithium, as disclosed in U.S. Patent No. 5,527,753, can also be used.

[0056] As a method for polymerizing a vinyl aromatic compound and a conjugated diene polymer using an organic alkali metal compound as a polymerization initiator, a conventionally known method can be applied. The polymerization method may be, for example, batch polymerization, continuous polymerization, or a combination of these. In particular, batch polymerization is suitable for obtaining a block copolymer (I) having excellent heat resistance. The polymerization temperature is preferably 0°C to 180°C, more preferably 30°C to 150°C. The polymerization time varies depending on the conditions, but is usually within 48 hours, preferably 0.1 to 10 hours. The polymerization atmosphere is preferably an inert gas atmosphere such as nitrogen gas. The polymerization pressure is not particularly limited, as long as it is set within a pressure range that can maintain the monomer and solvent in a liquid phase within the above temperature range. Furthermore, care must be taken to prevent impurities that may inactivate the catalyst and living polymer, such as water, oxygen, and carbon dioxide, from entering the polymerization system.

[0057] Furthermore, at the end of the polymerization step, a required amount of a bifunctional or higher functional coupling agent may be added to carry out a coupling reaction. The bifunctional coupling agent is not particularly limited and any known bifunctional coupling agent can be used. Examples of bifunctional coupling agents include, but are not limited to, alkoxysilane compounds such as trimethoxysilane, triethoxysilane, tetramethoxysilane, tetraethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, dichlorodimethoxysilane, dichlorodiethoxysilane, trichloromethoxysilane, and trichloroethoxysilane; dihalogen compounds such as dichloroethane, dibromoethane, dimethyldichlorosilane, and dimethyldibromosilane; and acid esters such as methyl benzoate, ethyl benzoate, phenyl benzoate, and phthalates. Furthermore, as the polyfunctional coupling agent having three or more functionalities, conventionally known ones can be used, and are not limited to the following. For example, polyhydric or higher alcohols, epoxidized soybean oil, diglycidyl bisphenol A, polyhydric epoxy compounds such as 1,3-bis(N-N'-diglycidylaminomethyl)cyclohexane, etc.; n (wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 to 4), such as methylsilyl trichloride, t-butylsilyl trichloride, silicon tetrachloride, and bromides thereof; n (wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 3 to 4), for example, polyvalent halogen compounds such as methyltin trichloride, t-butyltin trichloride, and tin tetrachloride. Dimethyl carbonate, diethyl carbonate, etc. may also be used.

[0058] The solution of block copolymer (I) obtained after the polymerization step is optionally subjected to removal of catalyst residue, and the solvent is separated to obtain block copolymer (I). Examples of methods for separating the solvent include a method in which a polar solvent that is a poor solvent for the block copolymer (I), such as acetone or alcohol, is added to the reaction solution after the hydrogenation reaction to precipitate and recover the block copolymer (I); a method in which the reaction solution is poured into hot water under stirring, and the solvent is removed and recovered by steam stripping; and a method in which the polymer solution is directly heated to distill off the solvent. The block copolymer (I) may contain various stabilizers such as phenol-based stabilizers, phosphorus-based stabilizers, sulfur-based stabilizers, and amine-based stabilizers.

[0059] The block copolymer (I) used in the elastomer composition of the present embodiment may have a "polar group" to the extent that impact resistance under low temperature conditions is not impaired. The polar groups are preferably present at a concentration that does not cause gelation. Examples of the "polar group" include, but are not limited to, an atomic group containing at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, a thiocarbonyl group, an acid halide group, an acid anhydride, a carboxylic acid group, a thiocarboxylic acid group, an aldehyde group, a thioaldehyde group, a carboxylic acid ester group, an amide group, a sulfonic acid group, a sulfonate ester group, a phosphoric acid group, a phosphoric acid ester group, an amino group, an imino group, a nitrile group, a pyridyl group, a quinoline group, an epoxy group, a thioepoxy group, a sulfide group, an isocyanate group, an isothiocyanate group, a silicon halide group, a silanol group, an alkoxy silicon group, a tin halide group, a boronic acid group, a boron-containing group, a boronate salt group, an alkoxytin group, and a phenyltin group.

[0060] The "polar group" can be formed by using a modifying agent on the block copolymer. Examples of the modifying agent include, but are not limited to, tetraglycidyl meta-xylenediamine, tetraglycidyl-1,3-bisaminomethylcyclohexane, ε-caprolactone, δ-valerolactone, 4-methoxybenzophenone, γ-glycidoxyethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyldimethylphenoxysilane, bis(γ-glycidoxypropyl)methylpropoxysilane, 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, N,N'-dimethylpropyleneurea, N-methylpyrrolidone, maleic acid, maleic anhydride, maleic anhydride imide, fumaric acid, itaconic acid, acrylic acid, methacrylic acid, glycidyl methacrylate, and crotonic acid.

[0061] The method for forming the "polar group" can be any known method, and is not particularly limited. Examples include a melt-kneading method and a method in which each component is dissolved or dispersed in a solvent or the like and reacted. Other examples include a method of polymerization by living anionic polymerization using a polymerization initiator having a functional group or an unsaturated monomer having a functional group, a method of modification by addition reaction of a modifier that forms or contains a functional group at the living terminal, and a method of reacting a block copolymer with an organic alkali metal compound such as an organolithium compound (metalation reaction), and then adding a modifier that has a functional group to the block polymer to which the organic alkali metal has been added.

[0062] (Method of producing elastomer composition) The method for producing the elastomer composition of the present embodiment is not particularly limited, and known methods can be applied. As a method for producing the elastomer composition of the present embodiment, for example, a method can be mentioned in which the above-mentioned component (I), component (II), and other additives, if necessary, are kneaded using a kneading device capable of uniformly mixing each known resin component to produce the elastomer composition. The kneading device is not particularly limited, and examples thereof include a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, and a roll. The melt-kneading temperature is preferably 100 to 400°C, more preferably 150 to 350°C. Dry blending can also be performed using various mixers, and methods such as melt-kneading using a general mixer such as a Banbury mixer, a single-screw extruder, a twin-screw extruder, a kneader, a multi-screw extruder, or a roll, or a method in which the components are dissolved or dispersed and mixed and then the solvent is removed by heating, can be used. In producing the elastomer composition of this embodiment, a melt mixing method using an extruder is preferred from the viewpoints of productivity and good kneading ability. The shape of the elastomer composition of the present embodiment is not particularly limited, and examples thereof include pellets, sheets, strands, chips, etc. After melt-kneading, a molded product can also be produced directly.

[0063] [Molded body] The molded article of this embodiment is an article molded from the elastomer composition of this embodiment described above. By processing and / or molding the elastomer composition of the present embodiment, a wide variety of molded articles can be obtained, such as sheets, films, containers, housings, etc. that can be used under ultra-low temperature conditions, as well as injection molded articles, blow molded articles, pressure molded articles, vacuum molded articles, extrusion molded articles, press molded articles, and other articles of various shapes. [Example]

[0064] Hereinafter, the present embodiment will be described in detail with reference to specific examples and comparative examples, but the present embodiment is not limited in any way by the following examples and comparative examples. The structure of the block copolymer (component (I)) used in the following examples and comparative examples was identified and the physical properties were measured as follows.

[0065] [Methods for identifying the structure of block copolymers and measuring their physical properties] ((1) Content of vinyl aromatic monomer units in block copolymers) The content (mass %) of vinyl aromatic monomer units in the block copolymer before hydrogenation was measured using an ultraviolet spectrophotometer (Shimadzu Corporation, "UV-2450").

[0066] ((2) Amount of vinyl bonds in block copolymer) The vinyl bond amount is the content of units (a) derived from 1,2-bonds and / or 3,4-bonds relative to the total amount of polymer blocks (B) mainly composed of conjugated diene monomer units in the block copolymer before hydrogenation. The vinyl bond content (%) of the block copolymer before hydrogenation was measured using an infrared spectrophotometer ("FT / IR-230" manufactured by JASCO Corporation) and calculated by the Hampton method.

[0067] ((3) Molecular weight and molecular weight distribution) The molecular weight distribution of the block copolymer before hydrogenation was determined by GPC (apparatus: LC-10 (trade name, manufactured by Shimadzu Corporation), column: TSKgel GMHXL (trade name, manufactured by Shimadzu Corporation, 4.6 mm x 30 cm)) as follows. In the GPC, tetrahydrofuran was used as the solvent. The measurement conditions were a temperature of 35°C. The molecular weight of the block copolymer was determined as the weight-average molecular weight (Mw) calculated from the molecular weight of the peak in the chromatogram using a calibration curve (prepared using the peak molecular weight of the standard polystyrene) obtained from the measurement of commercially available standard polystyrene. When there are multiple peaks in the chromatogram, the molecular weight was calculated as the average molecular weight calculated from the molecular weight of each peak and the composition ratio of each peak (calculated from the area ratio of each peak in the chromatogram). The molecular weight distribution of the block copolymer was determined as the ratio (Mw / Mn) of the molecular weight to the number average molecular weight (Mn) calculated using a calibration curve (prepared using the peak molecular weight of the standard polystyrene) obtained from the measurement of commercially available standard polystyrene in the same manner as for the molecular weight.

[0068] The values ​​measured in (1) to (3) above were measured using the block copolymer before hydrogenation as a sample, but these values ​​are not changed by the hydrogenation procedures in the examples and comparative examples described below.

[0069] ((4) Hydrogenation rate, vinyl hydrogenation rate) The hydrogenation rate is the ratio of the total content of the hydrogenated alkenyl monomer units (a1) of the above-mentioned units (a) and the hydrogenated alkenyl monomer units (b1) of the units (b) derived from 1,4-bonds to the total amount of the polymer block (B) mainly composed of conjugated diene monomer units. The hydrogenation rate (%) of the double bonds of the conjugated diene monomer units of the hydrogenated block copolymer after hydrogenation was measured using a nuclear magnetic resonance spectrometer (BRUKER "DPX-400"). The vinyl hydrogenation rate (%) was calculated as the ratio of the unit (a1) to the unit (a) (vinyl hydrogenation rate: (a1) / (a)).

[0070] ((5) tanδ peak temperature) First, the hydrogenated block copolymer was used as a sample, and these samples were cut into sheet-like molded bodies measuring 10 mm in width and 40 mm in length to prepare measurement samples. Next, this measurement sample was set in the torsion type geometry of the ARES device (manufactured by TA Instruments Corporation, trade name), and measurements were performed under the conditions of an effective measurement length of 25 mm, strain of 0.3%, frequency of 1 Hz, and heating rate of 3°C / min. The tan δ peak temperature was determined from the peak detected by automatic measurement using RSI Orchestrator (trade name, manufactured by TA Instruments Co., Ltd.).

[0071] [Preparation of hydrogenation catalyst] In the examples and comparative examples described later, the hydrogenation catalysts used in producing hydrogenated block copolymers were prepared by the following method. A reaction vessel equipped with a stirrer was purged with nitrogen, and 1 liter of dried and purified cyclohexane was placed in the vessel. Next, 100 mmol of bis(η5-cyclopentadienyl)titanium dichloride was added. While thoroughly stirring, an n-hexane solution containing 200 mmol of trimethylaluminum was added, and the reaction was carried out at room temperature for about 3 days. This produced a hydrogenation catalyst.

[0072] [Hydrogenated Block Copolymer] Hydrogenated products of block copolymers of vinyl aromatic compounds and conjugated dienes: hydrogenated block copolymers (1) to (14) were prepared as follows. The physical properties of the obtained hydrogenated block copolymer and the tan δ peak temperature obtained by the viscoelasticity spectrum are shown in Tables 1 and 2 below.

[0073] (Hydrogenated Block Copolymer (1)) Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 6.5 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.11 parts by mass of n-butyllithium as a polymerization initiator was added to 100 parts by mass of all monomers, and 0.2 moles of tetramethylethylenediamine (hereinafter referred to as TMEDA) was added to 1 mole of n-butyllithium, followed by polymerization at 70° C. for 20 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 87 parts by mass of butadiene was added and polymerization was carried out at 70° C. for 45 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 6.5 parts by mass of styrene was added, followed by the addition of heptanol to terminate the polymerization reaction, thereby obtaining a block copolymer (1). The obtained block copolymer (1) had a vinyl aromatic monomer unit content of 13% by mass, a unit (a) content derived from 1,2-bonds and / or 3,4-bonds (vinyl bond content: unit (a) / polymer block (B)) of 25%, and a weight-average molecular weight of 7.60×10 4 It was. The hydrogenation catalyst prepared as described above was added to the obtained block copolymer (1) in an amount of 90 ppm (Ti standard) per 100 parts by mass of the block copolymer, and hydrogen was then supplied at a rate of 0.2 L / s to carry out a hydrogenation reaction at a temperature of 80°C for 15 minutes to obtain a solution of the hydrogenated block copolymer. The resulting hydrogenated block copolymer solution was subjected to the deashing procedure described below to reduce the amount of metals resulting from the polymerization initiator and hydrogenation catalyst. Specifically, 30 parts by mass of a water / sulfuric acid mixture was added to 100 parts by mass of the hydrogenated block copolymer. The amount of sulfuric acid added was adjusted so that the pH of the water removed by decanter in a subsequent process would be 7.0. Most of the water was removed from the solution using a decanter until the amount of water was 3 parts by mass, and 0.4 mol of carbon dioxide gas per 1 mol of the metal polymerization initiator was added and mixed in. Then, 0.3 parts by mass of octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate was added as a stabilizer. The solution was subjected to the steam stripping method described in JP-B-05-54845, and most of the solvent was removed in water at 90 to 98°C. The aqueous dispersion slurry with a crumb concentration of about 5% by mass was then introduced into a twin-screw extruder to remove the solvent. This yielded a hydrogenated block copolymer (1). In the obtained hydrogenated block copolymer (1), when the total content of polymer block (B) was taken as 100%, the total content of the hydrogenated monomer units of the above units (a) (hydrogenated vinyl bond units (a1)) and the content of the hydrogenated alkenyl monomer units (b1) of the units (b) derived from 1,4-bonds (hydrogenation rate: ((a1) + (b1)) / (B)) was 34%, and the ratio of units (a1) to units (a) (hereinafter also referred to as vinyl hydrogenation rate) was 93%.

[0074] (Hydrogenated Block Copolymer (2)) Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 13.5 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.11 parts by mass of n-butyllithium per 100 parts by mass of the total monomers and 0.2 moles of TMEDA per mole of n-butyllithium were added, and polymerization was carried out at 70° C. for 20 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 73 parts by mass of butadiene was added and polymerization was carried out at 70° C. for 45 minutes. Next, a cyclohexane solution containing 13.5 parts by mass of styrene (concentration: 20% by mass) was added. Thereafter, heptanol was added to terminate the polymerization reaction, and the same hydrogenation reaction as in the hydrogenated block copolymer (1) was carried out for 13 minutes. As a result, a hydrogenated block copolymer (2) was obtained. The hydrogenated block copolymer (2) obtained as described above had a vinyl aromatic monomer unit content of 27% by mass, a vinyl bond content of 25%, and a weight-average molecular weight of 7.80×10 4 The hydrogenation rate was 34% and the vinyl hydrogenation rate was 95%.

[0075] (Hydrogenated Block Copolymer (3)) The same operations as in the above-mentioned hydrogenated block copolymer (1) were carried out to carry out the polymerization reaction and hydrogenation reaction, except that the amount of TMEDA added was changed to 0.11 mol per 1 mol of n-butyllithium, thereby obtaining hydrogenated block copolymer (3). The hydrogenated block copolymer (3) obtained as described above had a vinyl aromatic monomer unit content of 13% by mass, a vinyl bond content of 15%, and a weight-average molecular weight of 7.20×10 4 The hydrogenation rate was 34% and the vinyl hydrogenation rate was 95%.

[0076] (Hydrogenated Block Copolymer (4)) The same operations as in the above-mentioned hydrogenated block copolymer (1) were carried out to carry out the polymerization reaction and hydrogenation reaction, except that the amount of TMEDA added was changed to 0.25 mol per 1 mol of n-butyllithium, thereby obtaining hydrogenated block copolymer (4). The hydrogenated block copolymer (4) obtained as described above had a vinyl aromatic monomer unit content of 13% by mass, a vinyl bond content of 30%, and a weight-average molecular weight of 7.30×10 4The hydrogenation rate was 34% and the vinyl hydrogenation rate was 90%.

[0077] (Hydrogenated Block Copolymer (5)) The same operations as in the above-mentioned hydrogenated block copolymer (1) were carried out to carry out the polymerization reaction and hydrogenation reaction, except that the amount of TMEDA added was changed to 0.74 mol per 1 mol of n-butyllithium, thereby obtaining hydrogenated block copolymer (5). The hydrogenated block copolymer (5) obtained as described above had a vinyl aromatic monomer unit content of 13% by mass, a vinyl bond content of 50%, and a weight-average molecular weight of 7.30×10 4 The hydrogenation rate was 34% and the vinyl hydrogenation rate was 88%.

[0078] (Hydrogenated Block Copolymer (6)) The polymerization reaction and hydrogenation reaction were carried out in the same manner as in the above-mentioned hydrogenated block copolymer (1), except that the hydrogenation reaction time was changed to 11 minutes, to obtain hydrogenated block copolymer (6). The hydrogenated block copolymer (6) obtained as described above had a vinyl aromatic monomer unit content of 13% by mass, a vinyl bond content of 25%, and a weight-average molecular weight of 7.60×10 4 The hydrogenation rate was 25% and the vinyl hydrogenation rate was 95%.

[0079] (Hydrogenated Block Copolymer (7)) The polymerization reaction and hydrogenation reaction were carried out in the same manner as in the above-mentioned hydrogenated block copolymer (1), except that the hydrogenation reaction time was changed to 20 minutes, to obtain hydrogenated block copolymer (7). The hydrogenated block copolymer (7) obtained as described above had a vinyl aromatic monomer unit content of 13% by mass, a vinyl bond content of 25%, and a weight-average molecular weight of 7.60×10 4 The hydrogenation rate was 45% and the vinyl hydrogenation rate was 95%.

[0080] (Hydrogenated Block Copolymer (8)) The polymerization reaction and hydrogenation reaction were carried out in the same manner as in the above-mentioned hydrogenated block copolymer (1), except that the hydrogenation reaction time was changed to 24 minutes, to obtain hydrogenated block copolymer (8). The hydrogenated block copolymer (8) obtained as described above had a vinyl aromatic monomer unit content of 13% by mass, a vinyl bond content of 25%, and a weight-average molecular weight of 7.40×10 4 The hydrogenation rate was 55% and the vinyl hydrogenation rate was 94%.

[0081] (Hydrogenated Block Copolymer (9)) Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, 0.12 parts by mass of n-butyllithium was added as a polymerization initiator to 100 parts by mass of all the monomers, and 0.19 moles of TMEDA were added to 1 mole of n-butyllithium. Next, a cyclohexane solution (concentration: 20% by mass) containing 100 parts by mass of butadiene was added, and polymerization was carried out for 45 minutes at 70° C. Thereafter, heptanol was added to terminate the polymerization reaction, and a hydrogenation reaction similar to that for the hydrogenated block copolymer (1) was carried out for 18 minutes to obtain hydrogenated block copolymer (9). The hydrogenated block copolymer (9) obtained as described above had a vinyl bond content of 25% and a weight-average molecular weight of 6.80×10 4 The hydrogenation rate was 34% and the vinyl hydrogenation rate was 95%.

[0082] (Hydrogenated Block Copolymer (10)) Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 17.5 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.10 parts by mass of n-butyllithium as a polymerization initiator was added to 100 parts by mass of the total monomers, and 0.2 moles of TMEDA were added to 1 mole of n-butyllithium, followed by polymerization at 70° C. for 20 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 65 parts by mass of butadiene was added and polymerization was carried out at 70° C. for 45 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 17.5 parts by mass of styrene was added, followed by the addition of heptanol to terminate the polymerization reaction, and the same hydrogenation reaction as for the hydrogenated block copolymer (1) was carried out for 12 minutes to obtain the hydrogenated block copolymer (10). The hydrogenated block copolymer (10) obtained as described above had a vinyl aromatic monomer unit content of 35% by mass, a vinyl bond content of 25%, and a weight-average molecular weight of 8.50×10 4 The hydrogenation rate was 34% and the vinyl hydrogenation rate was 93%.

[0083] (Hydrogenated Block Copolymer (11)) The same operations as in the above-mentioned hydrogenated block copolymer (1) were carried out to carry out the polymerization reaction and hydrogenation reaction, except that the amount of TMEDA added was changed to 1.2 mol per 1 mol of n-butyllithium, thereby obtaining hydrogenated block copolymer (11). The hydrogenated block copolymer (11) obtained as described above had a vinyl aromatic monomer unit content of 13% by mass, a vinyl bond content of 60%, and a weight-average molecular weight of 7.30×10 4 The hydrogenation rate was 34% and the vinyl hydrogenation rate was 87%.

[0084] (Block copolymer (12)) A polymerization reaction was carried out in the same manner as in the hydrogenated block copolymer (1) above, except that the hydrogenation reaction time was changed to 0 minutes, to obtain a block copolymer (12). The block copolymer (12) obtained as described above had a vinyl aromatic monomer unit content of 13% by mass, a vinyl bond content of 25%, and a weight-average molecular weight of 7.60×10 4 The hydrogenation rate was 0% and the vinyl hydrogenation rate was 0%.

[0085] (Hydrogenated Block Copolymer (13)) The polymerization reaction and hydrogenation reaction were carried out in the same manner as in the above-mentioned hydrogenated block copolymer (1), except that the hydrogenation reaction time was changed to 27 minutes, to obtain hydrogenated block copolymer (13). The hydrogenated block copolymer (13) obtained as described above had a vinyl aromatic monomer unit content of 13% by mass, a vinyl bond content of 25%, and a weight-average molecular weight of 7.60×10 4 The hydrogenation rate was 60% and the vinyl hydrogenation rate was 98%.

[0086] (Hydrogenated Block Copolymer (14)) The polymerization reaction and hydrogenation reaction were carried out in the same manner as in the hydrogenated block copolymer (1) above, except that the hydrogenation reaction temperature was changed to 45°C, to obtain a hydrogenated block copolymer (14). The hydrogenated block copolymer (14) obtained as described above had a vinyl aromatic monomer unit content of 13% by mass, a vinyl bond content of 25%, and a weight-average molecular weight of 7.60×10 4 The hydrogenation rate was 34% and the vinyl hydrogenation rate was 78%.

[0087] (Hydrogenated Block Copolymer (15)) The polymerization reaction and hydrogenation reaction were carried out in the same manner as in the above-mentioned hydrogenated block copolymer (1), except that the hydrogenation reaction time was changed to 45 minutes, to obtain hydrogenated block copolymer (15). The hydrogenated block copolymer (15) obtained as described above had a vinyl aromatic monomer unit content of 13% by mass, a vinyl bond content of 25%, and a weight-average molecular weight of 7.60×10 4 The hydrogenation rate was 95% and the vinyl hydrogenation rate was 98%.

[0088] (Hydrogenated Block Copolymer (16)) Batch polymerization was carried out using a tank reactor (internal volume: 10 L) equipped with a stirrer and a jacket. First, a cyclohexane solution containing 2.5 parts by mass of styrene (concentration: 20% by mass) was added. Next, 0.11 parts by mass of n-butyllithium as a polymerization initiator was added to 100 parts by mass of the total monomers, and 0.2 moles of TMEDA were added to 1 mole of n-butyllithium, followed by polymerization at 70° C. for 20 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 95 parts by mass of butadiene was added and polymerization was carried out at 70° C. for 45 minutes. Next, a cyclohexane solution (concentration: 20% by mass) containing 2.5 parts by mass of styrene was added, followed by addition of heptanol to terminate the polymerization reaction. A hydrogenation reaction similar to that for the hydrogenated block copolymer (1) was carried out for 16 minutes to obtain a hydrogenated block copolymer (16). The hydrogenated block copolymer (16) obtained as described above had a vinyl aromatic monomer unit content of 5% by mass, a vinyl bond content of 25%, and a weight-average molecular weight of 7.30×10 4 The hydrogenation rate was 34% and the vinyl hydrogenation rate was 93%.

[0089] [Table 1]

[0090] [Table 2]

[0091] [Examples 1 to 16], [Comparative Examples 1 to 9] The elastomer compositions were prepared using the resulting hydrogenated block copolymers (1) to (16) as component (I) and the following component (II) according to the following preparation method. The component ratios and evaluation results for each example are shown in Tables 3 to 5 below.

[0092] (Component (II): Cyclic olefin resin) The following commercially available products were used as component (II). Cyclic olefin copolymers: TOPAS 8007F (manufactured by Polyplastics Co., Ltd., abbreviated as "8007F" in the table)

[0093] (Method for preparing elastomer composition) The temperature of the entire area in the length direction of the twin-screw extruder was set to 180 to 200°C, and the components (I) and (II) were compounded in the twin-screw extruder. The extrusion conditions were a screw rotation speed of 250 rpm and an extrusion rate of 5 kg / h. In general, components (I) and (II) were fed from the throat of a twin-screw extruder. The strands discharged from the twin-screw extruder were pelletized and dried in an oven at 50°C. The dried pellets were used to injection mold ASTM dumbbells for measuring physical properties at a cylinder temperature of 250°C and a mold temperature of 40°C.

[0094] (Method for evaluating elastomer compositions) <(1) Impact resistance> The above-mentioned ASTM dumbbell was cut out to prepare a rectangular test piece measuring 63.5 mm x 12.7 mm x 4 mm. The prepared test pieces were used to measure the notched Izod impact strength in accordance with JIS K 7110;1999, and evaluated as impact resistance. The measurement temperatures were 23°C, -30°C, and -50°C. The unit is kJ / m 2 is. The larger the Izod impact strength value, the better the impact resistance. In particular, Examples 1, 3, 4, and 6 exhibited impact strengths of 14.0 kJ or more at room temperature and 3.5 kJ or more even under cryogenic conditions. Furthermore, it was found that in Examples 11 to 16, the impact strength under cryogenic temperature conditions was improved by increasing the amount of hydrogenated block copolymer (1) added. On the other hand, the elastomer compositions of Comparative Example 4, in which block copolymer (12) with a hydrogenation rate of 0% was added, and Example 9, in which block copolymer (14) with a low vinyl hydrogenation rate was added, showed reduced impact resistance due to the above-mentioned effects.

[0095] <(2) Flexural modulus> The stress-strain curve was measured in accordance with JIS K 7074, and the flexural modulus was evaluated. The test specimens were ASTM dumbbells, and the flexural modulus was calculated by the secant method from the stress-strain curve obtained in the three-point bending test. A smaller value indicates lower rigidity, i.e., greater flexibility. By adding the hydrogenated block copolymer of component (I) to component (II) in an amount of 1% by mass or more in the elastomer composition, the flexural modulus became 2000 MPa or less. Furthermore, it was found from Comparative Examples 8 and 9 that sufficient flexibility could not be obtained when the amount of component (I) hydrogenated block copolymer added was less than 1% by mass.

[0096] [Table 3]

[0097] [Table 4]

[0098] [Table 5] [Industrial Applicability]

[0099] The elastomer composition of the present invention has industrial applicability in applications such as aircraft equipment and refrigeration equipment parts that are exposed to cryogenic environments during use, pharmaceutical containers and food packaging materials that must be stored, preserved, and transported at low temperatures, etc.

Claims

1. Component (I): a block copolymer (I) having a polymer block (A) mainly composed of vinyl aromatic monomer units and a polymer block (B) mainly composed of conjugated diene monomer units; Component (II): a cyclic olefin resin; Contains the mass ratio of the component (I) to the component (II) is component (I) / component (II)=1 / 99 to 90 / 10; The component (I) satisfies the following conditions (i) to (iii): <Condition (i)>: The content of the vinyl aromatic monomer unit is 1.0 to 30% by mass based on the total amount of the component (I). <Condition (ii)>: The polymer block (B) contains units (a) derived from a 1,2-bond and / or a 3,4-bond and units (b) derived from a 1,4-bond, and the content of the units (a) is 1.0 to 55% based on the total amount of the polymer block (B). <Condition (iii)>: The polymer block (B) contains a hydrogenated alkenyl monomer unit (a1) of the unit (a) derived from the 1,2-bond and / or the 3,4-bond, and a hydrogenated alkenyl monomer unit (b1) of the unit (b) derived from the 1,4-bond, and the total content of the alkenyl monomer unit (a1) and the alkenyl monomer unit (b1) is 5.0 to 55% based on the total amount of the polymer block (B).

2. The component (I) further satisfies the following condition (iv): The elastomer composition of claim 1. <Condition (iv)>: The content of the hydrogenated alkenyl monomer units (a1) of the units (a) derived from the 1,2-bond and / or the 3,4-bond is 80% or more based on the total amount of the units (a) derived from the 1,2-bond and / or the 3,4-bond.

3. A molded article of the elastomer composition according to claim 1 or 2.

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