JP7481884B2 - Ethylene/α-olefin/non-conjugated polyene copolymer composition and use thereof - Google Patents

Description

The present invention relates to an ethylene/α-olefin/non-conjugated polyene copolymer composition, and more specifically to an ethylene/α-olefin/non-conjugated polyene copolymer composition that has good injection moldability and can provide molded articles with excellent engine oil barrier properties, and uses thereof.

Olefin-based thermoplastic elastomers, which are a type of thermoplastic elastomer and are obtained by crosslinking a composition of an ethylene-α-olefin-non-conjugated polyene copolymer and a crystalline olefin polymer, are lightweight and easy to recycle, and therefore are widely used as energy-saving and resource-saving thermoplastic elastomers, particularly as a replacement for vulcanized rubber, in automobile parts such as hoses, pipes, and boots (blow molded products) for automobiles (for example, Patent Documents 1 and 2).

However, while these automobile parts are always required to be made lighter to improve fuel economy, the thermoplastic elastomers used contain a lot of filler, which tends to increase the specific gravity, preventing the weight reduction of parts. Furthermore, these automobile parts are used in places that come into contact with lubricating oils and greases, but since olefin-based thermoplastic elastomers generally have low oil resistance to paraffin-based process oils, these automobile parts obtained containing olefin-based thermoplastic elastomers also have low oil resistance, and further improvement is required.

JP 2001-294714 A JP 2011-202136 A

The object of the present invention is to obtain an ethylene-α-olefin-non-conjugated polyene copolymer composition that has good injection moldability and can provide molded articles with excellent engine oil barrier properties.

The present invention relates to an ethylene-α-olefin-non-conjugated polyene copolymer (A) containing ethylene (a1), α-olefin (a2), and non-conjugated polyene (a3) as constituent units, and an ethylene-α-olefin-non-conjugated polyene copolymer composition containing, relative to 100 parts by mass of the copolymer (A), 20 to 300 parts by mass of carbon black (C), 0.1 to 10 parts by mass of fatty acid amide (D), 10 to 300 parts by mass of inorganic filler (heavy calcium carbonate) (E), and 0.2 to 30 parts by mass of organic peroxide (F), and uses thereof.

The ethylene-α-olefin-non-conjugated polyene copolymer composition of the present invention has good injection moldability, and the crosslinked molded articles obtained by molding the composition have excellent engine oil barrier properties, making them suitable for a variety of applications including automotive parts.

<Ethylene/α-olefin/non-conjugated polyene copolymer (A)>
The ethylene-α-olefin-non-conjugated polyene copolymer (A) (hereinafter, may be referred to as "copolymer (A)"), which is one of the copolymers constituting the ethylene-α-olefin-non-conjugated polyene copolymer composition of the present invention, is an ethylene-α-olefin-non-conjugated polyene copolymer having structural units derived from ethylene (a1), an α-olefin (a2), and a non-conjugated polyene (a3).

The α-olefin (a2) constituting the copolymer (A) is usually an α-olefin having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-eicosene. Among these, α-olefins having 3 to 8 carbon atoms, such as propylene, 1-butene, 1-hexene, and 1-octene, are preferred, with propylene being particularly preferred. Such α-olefins are preferred because the raw material costs are relatively low, the resulting copolymer (A) exhibits excellent mechanical properties, and a molded article having rubber elasticity can be obtained.

The α-olefin (a2) constituting the copolymer (A) according to the present invention may be used alone or in combination of two or more. In other words, the copolymer (A) contains structural units derived from at least one α-olefin (a2) having 3 to 20 carbon atoms, and may contain structural units derived from two or more α-olefins (a2) having 3 to 20 carbon atoms.

The non-conjugated polyene (a3) constituting the copolymer (A) according to the present invention is not particularly limited as long as it is a compound having two or more non-conjugated unsaturated bonds, but is preferably a non-conjugated polyene containing, in the molecule, a total of two or more partial structures selected from the group consisting of the following general formulas (I) and (II).

Specific examples of the non-conjugated polyene (a3) include 5-vinyl-2-norbornene (VNB), norbornadiene, 1,4-hexadiene, and dicyclopentadiene. Among these, it is preferable that the non-conjugated polyene (a3) contains VNB, and it is more preferable that the non-conjugated polyene (a3) is VNB, because VNB is highly available, has good reactivity with peroxide during the crosslinking reaction after polymerization, and tends to improve the heat resistance of the polymer composition. The non-conjugated polyene (a3) may be used alone or in combination of two or more kinds.

The copolymer (A) according to the present invention may have, in addition to the structural units derived from the above (a1), (a2), and (a3), a structural unit derived from a non-conjugated polyene (a4) containing only one partial structure selected from the group consisting of the above general formulas (I) and (II) in the molecule.

The non-conjugated polyene (a4) may be 5-ethylidene-2-norbornene (ENB), 5-methylene-2-norbornene, 5-(2-propenyl)-2-norbornene, 5-(3-butenyl)-2-norbornene, 5-(1-methyl-2-propenyl)-2-norbornene, 5-(4-pentenyl)-2-norbornene, 5-(1-methyl-3-butenyl)-2-norbornene, 5-(5-hexenyl)-2-norbornene, 5-(1-methyl-4-pentenyl)-2-norbornene, 5-(2,3-dimethyl-3-butenyl)-2-norbornene, 5-(2-ethyl-3-butenyl)-2-norbornene, Examples of such compounds include 5-(1,2-dimethyl-5-hexenyl)-2-norbornene, 5-(1,2,3-trimethyl-4-pentenyl)-2-norbornene, 5-(6-heptenyl)-2-norbornene, 5-(3-methyl-5-hexenyl)-2-norbornene, 5-(3,4-dimethyl-4-pentenyl)-2-norbornene, 5-(3-ethyl-4-pentenyl)-2-norbornene, 5-(7-octenyl)-2-norbornene, 5-(2-methyl-6-heptenyl)-2-norbornene, 5-(1,2-dimethyl-5-hexenyl)-2-norbornene, 5-(5-ethyl-5-hexenyl)-2-norbornene, and 5-(1,2,3-trimethyl-4-pentenyl)-2-norbornene. Among these, ENB is preferred because it is easily available, has a high reactivity with sulfur and vulcanization accelerators during the crosslinking reaction after polymerization, is easy to control the crosslinking rate, and is easy to obtain good mechanical properties. The non-conjugated polyene (a4) may be used alone or in combination of two or more.

When the copolymer (A) according to the present invention contains a structural unit derived from the non-conjugated polyene (a4), the proportion is not particularly limited as long as it does not impair the object of the present invention, but is usually contained at a weight fraction of about 0 to 20% by weight, preferably 0 to 8% by weight, and more preferably 0.01 to 8% by weight (where the sum of the weight fractions of (a1), (a2), (a3), and (a4) is 100% by weight).

The copolymer (A) according to the present invention preferably satisfies the following requirements (i) to (v) (hereinafter also referred to as requirements (i) to (v), respectively).
(i) The molar ratio of ethylene (a1)/α-olefin (a2) is 40/60 to 99.9/0.1.
(ii) The weight fraction of the structural units derived from the non-conjugated polyene (a3) is 0.07% by weight to 10% by weight in 100% by weight of the ethylene/α-olefin/non-conjugated polyene copolymer.
(iii) The weight average molecular weight (Mw) of the ethylene-α-olefin-non-conjugated polyene copolymer, the weight fraction of the structural unit derived from the non-conjugated polyene (a3) (weight fraction (wt %) of (a3)), and the molecular weight of the non-conjugated polyene (a3) (molecular weight of (a3)) satisfy the following formula (1):
4.5≦Mw×weight fraction of (a3)/100/molecular weight of (a3)≦40 (1)
(iv) The ratio P(η*(ω=0.1)/η*(ω=100)) of the complex viscosity η ^* ₍ ω _=0.1) (Pa sec) at a frequency ω=0.1 rad/s to the complex viscosity η ^* ₍ ω ₌₁₀₀₎ (Pa sec) at a frequency ω ₌ 100 _rad /s, which are obtained by linear viscoelasticity ^measurement _{( 190°} ^C ) using a rheometer, the intrinsic viscosity [η], and the weight fraction of the constituent unit derived from the non-conjugated polyene (a3) (weight fraction of (a3)), satisfy the following formula (2):
P / ([η] ^2.9 ) ≦ weight fraction of (a3) × 6 (2)
(v) The number of long chain branches per 1,000 carbon atoms (LCB _1000C ) and the natural logarithm of the weight average molecular weight (Mw) [Ln(Mw)], both obtained using 3D-GPC, satisfy the following formula (3):
LCB _1000C ≦1−0.07×Ln(Mw) … (3)

Requirement (i)
The requirement (i) specifies that the molar ratio of ethylene (a1)/α-olefin (a2) in the copolymer (A) satisfies 40/60 to 99.9/0.1, and this molar ratio is preferably 50/50 to 90/10, more preferably 55/45 to 85/15, and even more preferably 55/45 to 78/22.

By using the copolymer (A) satisfying the requirement (i), it is possible to obtain a copolymer composition excellent in rubber elasticity, mechanical strength and flexibility. The amount of ethylene (the content of structural units derived from ethylene (a1)) and the amount of α-olefin (the content of structural units derived from α-olefin (a2)) in the copolymer (A) can be determined by ¹³ C-NMR.

Requirement (ii)
Requirement (ii) specifies that in the copolymer (A) according to the present invention, the weight fraction of the structural units derived from the non-conjugated polyene (a3) is in the range of 0.07% by weight to 10% by weight in 100% by weight of the copolymer (A) (i.e., in the total weight fraction of all structural units, 100% by weight). The weight fraction of the structural units derived from the non-conjugated polyene (a3) is preferably 0.1% by weight to 8.0% by weight, more preferably 0.5% by weight to 5.0% by weight.

Copolymer (A) satisfying requirement (ii) has sufficient hardness and excellent mechanical properties, and when crosslinked with a peroxide, it exhibits a fast crosslinking rate. The amount of non-conjugated polyene (a3) in copolymer (A) (the content of constituent units derived from non-conjugated polyene (a3)) can be determined by ¹³ C-NMR.

Requirement (iii)
Requirement (iii) specifies that in the copolymer (A) according to the present invention, the weight average molecular weight (Mw) of the copolymer (A), the weight fraction of the constitutional unit derived from the non-conjugated polyene (a3) in the copolymer (A) (weight fraction of (a3): weight %), and the molecular weight of the non-conjugated polyene (a3) (molecular weight of (a3)) satisfy the above formula (1). The above formula (1) in requirement (iii) is preferably the following formula (1'):
4.5≦Mw×weight fraction of (a3)/100/molecular weight of (a3)≦35 (1′)

When the copolymer (A) of the present invention satisfies the requirement (iii), the content of structural units derived from the non-conjugated polyene (a3) is appropriate, and a molded article exhibiting sufficient crosslinking performance, excellent crosslinking rate, and excellent mechanical properties can be produced. The weight average molecular weight (Mw) of the copolymer (A) can be determined as a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

In the copolymer (A) according to the present invention, when "weight fraction of Mw × (a3)/100/molecular weight of (a3)" satisfies the above formula (1) or (1'), the degree of crosslinking is appropriate, and a molded product having a good balance of mechanical properties and heat aging resistance can be produced. If the value of "weight fraction of Mw × (a3)/100/molecular weight of (a3)" is too low, the crosslinking may be insufficient, resulting in a slow crosslinking rate, and if the value is too high, excessive crosslinking may occur, resulting in deterioration of mechanical properties.

Requirement (iv)
Requirement (iv) specifies that the ratio P(η*(ω=0.1)/η*(ω=100)) of the complex viscosity η ^* ₍ ω _=0.1) (Pa·sec) at a frequency ω= _{0.1 rad} /s to the complex viscosity η ^* ₍ ω ₌₁₀₀₎ (Pa·sec) at a ^frequency _ω = _{100 rad} / ^s , the intrinsic viscosity [η], and the weight fraction of the structural unit derived from the non-conjugated polyene (a3) (weight fraction of (a3): weight %) of the copolymer (A) obtained by linear viscoelasticity measurement (190°C) using a rheometer, satisfy the above formula (2). The above formula (2) in requirement (iv) is preferably the following formula (2'):

P/([η] ^2.9 )≦weight fraction of (a3)×5.7 (2′)
Here, the ratio P(η ^* (ω=0.1)/η ^* ₍ ω _{= 100))} of the complex viscosity η ^* ₍ ω _=0.1) at a frequency ω=0.1 rad/s to the complex viscosity η ^* ₍ ω ₌₁₀₀ ) at a frequency _ω =100 rad/s represents the frequency dependency of the viscosity, and P/([η] ^2.9 ) on the left side of formula (2) tends to show a high value when there are many long chain branches, although it is affected by short chain branches and molecular weight. Generally, in an ethylene-α-olefin-non-conjugated polyene copolymer, the more structural units derived from non-conjugated polyenes are contained, the more long chain branches are contained. However, it is considered that the copolymer (A) of the present invention has less long chain branches than the conventionally known ethylene-α-olefin-non-conjugated polyene copolymers, and therefore can satisfy the above formula (2).

In the present invention, the P value is the ratio (η* ratio) of the complex viscosity at 0.1 rad/s and the complex viscosity at 100 rad/s, which are measured at 190°C, 1.0% strain, and various frequencies using a viscoelasticity measuring device Ares (manufactured by ^Rheometric Scientific). The intrinsic viscosity [η] is the value measured in decalin at 135°C.

Requirement (v)
Requirement (v) specifies that the number of long chain branches per 1000 carbon atoms (LCB _1000C ) and the natural logarithm [Ln(Mw)] of the weight average molecular weight (Mw) of the copolymer (A) according to the present invention, obtained by 3D-GPC, satisfy the above formula (3). The above formula (3) in requirement (v) is preferably the following formula (3'):

LCB _1000C ≦1−0.071×Ln(Mw) … (3')
The upper limit of the long chain branch content per unit carbon number of the copolymer (A) according to the present invention is specified by the above formula (3) or (3').

When the copolymer (A) of the present invention satisfies requirement (v), it has a low proportion of long chain branches, and has excellent curing properties when crosslinked using a peroxide, and can produce a molded product with excellent heat aging resistance.

Here, Mw and the number of long chain branches per 1000 carbon atoms (LCB _1000C ) can be determined by a structural analysis method using 3D-GPC. In this specification, specifically, they were determined as follows.

The absolute molecular weight distribution was measured using a 3D-high temperature GPC device PL-GPC220 (Polymer Laboratories), and the intrinsic viscosity was measured using a viscometer. The main measurement conditions were as follows:
Detector: Differential refractometer/GPC device built-in two-angle light scattering photometer PD2040 type (Precision Detectors)
Bridge type viscometer PL-BV400 (Polymer Laboratories)
Column: 2 TSKgel GMH _HR -H(S)HT + 1 TSKgel GMH _HR -M(S) (each with inner diameter of 7.8 mm and length of 300 mm)
Temperature: 140℃
Mobile phase: 1,2,4-trichlorobenzene (containing 0.025% BHT)
Injection volume: 0.5mL
Sample concentration: ca 1.5mg/mL
Sample filtration: Filtration through a sintered filter with a pore size of 1.0 μm. In the above, the dn/dc value required to determine the absolute molecular weight was determined for each sample from the dn/dc value of standard polystyrene (molecular weight 190,000), which was 0.053, and the response intensity of the differential refractometer per unit injected mass.

The long chain branching parameter g'i for each eluted component was calculated from the relationship between the intrinsic viscosity obtained from the viscometer and the absolute molecular weight obtained from the light scattering photometer using the following formula (v-1).

Here, the relation: [η]=KM ^v ; v=0.725 was applied.
Further, the average values of g' were calculated from the following formulas (v-2), (v-3), and (v-4). Note that a trendline assuming the presence of only short chain branches was determined for each sample.

Furthermore, using g'w, the number of branching points per molecular chain BrNo, the number of long chain branches per 1000 carbons _LCB1000C , and the branching degree λ per unit molecular weight were calculated. BrNo was calculated using the following Zimm-Stockmayer formula (v-5), and _LCB1000C and λ were calculated using the following formulas (v-6) and (v-7). g is the long chain branching parameter calculated from the radius of gyration Rg, and the following simple correlation is made between g' calculated from the limiting viscosity. Various values of ε in the formula have been proposed depending on the shape of the molecule. Here, the calculation was performed assuming ε = 1 (i.e. g' = g).

λ=BrNo/M...(V-6)
LCB _1000C = λ × 14000 ... (V-7)
In formula (V-7), "14000" represents a molecular weight equivalent to 1000 methylene (CH ₂ ) units.

The intrinsic viscosity [η] of the copolymer (A) according to the present invention is preferably 0.1 to 5 dL/g, more preferably 0.5 to 5.0 dL/g, and even more preferably 0.9 to 4.0 dL/g.

In addition, the weight average molecular weight (Mw) of the copolymer (A) according to the present invention is preferably 10,000 to 600,000, more preferably 30,000 to 500,000, and even more preferably 50,000 to 400,000.

It is preferable that the copolymer (A) according to the present invention satisfies both of the above-mentioned intrinsic viscosity [η] and weight average molecular weight (Mw).
In the copolymer (A) according to the present invention, as described above, the non-conjugated polyene (a3) preferably contains VNB, and more preferably is VNB. That is, in the above-mentioned formula (1), formula (2), and formula (4) described later, it is preferable that the "weight fraction of (a3)" is the "weight fraction of VNB" (% by weight).

As described above, the copolymer (A) according to the present invention preferably contains, in addition to the structural units derived from (a1), (a2), and (a3), a structural unit derived from the non-conjugated polyene (a4) in a weight fraction of 0 to 20% by weight (where the sum of the weight fractions of (a1), (a2), (a3), and (a4) is 100% by weight). In this case, it is preferable that the following requirement (vi) is satisfied.

Requirement (vi)
The weight average molecular weight (Mw) of the copolymer (A) according to the present invention, the weight fraction of the structural unit derived from the non-conjugated polyene (a3) (weight fraction (wt%) of (a3)), the weight fraction of the structural unit derived from the non-conjugated polyene (a4) (weight fraction (wt%) of (a4)), the molecular weight of the non-conjugated polyene (a3) (molecular weight of (a3)), and the molecular weight of the non-conjugated polyene (a4) (molecular weight of (a4)) satisfy the following formula (4).

4.5≦Mw×{(weight fraction of (a3)/100/molecular weight of (a3))+(weight fraction of (a4)/100/molecular weight of (a4))}≦45 (4)
Formula (4) specifies the content of the non-conjugated diene (the total of (a3) and (a4)) in one copolymer molecule.

When the copolymer (A) containing the structural unit derived from the above (a4) satisfies the formula (4), a molded article having excellent mechanical properties and heat aging resistance can be obtained.
If the requirement (vi) is not satisfied and the value of "Mw × {(weight fraction of (a3)/100/molecular weight of (a3)) + (weight fraction of (a4)/100/molecular weight of (a4))}" in formula (4) is too low, that is, if the content of the non-conjugated diene is too low, sufficient crosslinking may not be achieved and appropriate mechanical properties may not be obtained. Conversely, if the value is too high, that is, if the content of the non-conjugated diene is too high, excessive crosslinking may occur, resulting in deterioration of mechanical properties and further deterioration of heat aging resistance.

Requirement (vii)
The copolymer (A) according to the present invention is not particularly limited, but it is preferable that the complex viscosity η ^* ₍ ω _=0.01) (Pa·sec) at a frequency ω=0.01 rad/s and the complex viscosity η ^* ₍ ω ₌₁₀₎ (Pa·sec) at a frequency ω=10 rad/s, which are obtained by linear viscoelasticity measurement (190° C.) using a rheometer, and the apparent iodine value derived from the non-conjugated polyene (a3), satisfy the following formula (5).

Log{η ^* ₍ ω _=0.01) }/Log{η ^* ₍ ω ₌₁₀₎ }≦0.0753×{apparent iodine value derived from non-conjugated polyene (a3)}+1.42 (5)
Here, the complex viscosities η ^* ₍ ω _=0.01) and η ^* ₍ ω ₌₁₀₎ are calculated in the same manner as the complex viscosities η ^* ₍ ω _=0.1) and η ^* ₍ ω ₌₁₀₀₎ in requirement (iv) except for the measurement frequency. The apparent iodine value derived from the non-conjugated polyene (a3) is calculated by the following formula.

Apparent iodine value derived from (a3)=weight fraction of (a3)×253.81/molecular weight of (A3) In the above formula (5), the left side represents the shear rate dependency which is an index of the amount of long chain branching, and the right side represents an index of the content of non-conjugated polyene (a3) that is not consumed as long chain branching during polymerization. If the above copolymer (A) satisfies the above formula (5), it is preferable because the degree of long chain branching is not too high. On the other hand, if the above formula (5) is not satisfied, it can be seen that a large proportion of the copolymerized non-conjugated polyene (a3) is consumed to form long chain branches.

Furthermore, the copolymer (A) according to the present invention preferably contains a sufficient amount of structural units derived from the non-conjugated polyene (a3), and it is more preferable that the weight fraction of the structural units derived from the non-conjugated polyene (a3) in the copolymer (weight fraction (wt%) of (a3)) and the weight average molecular weight (Mw) of the copolymer satisfy the following formula (6).
6-0.45 × Ln (Mw) ≦ Weight fraction of (a3) ≦ 10 (6)

In addition, the copolymer (A) of the present invention has a number (n _a3 ) of structural units derived from non-conjugated polyene (a3) per weight average molecular weight (Mw) of preferably 6 or more, more preferably 6 or more and 40 or less, even more preferably 7 or more and 39 or less, and particularly preferably 10 or more and 38 or less.

The copolymer (A) according to the present invention contains a sufficient amount of structural units derived from a non-conjugated polyene (a3) such as VNB, has a low content of long chain branches, has excellent curing characteristics when crosslinked using a peroxide, has good moldability, and has an excellent balance of physical properties such as mechanical properties, and is particularly excellent in heat aging resistance.

In addition, the copolymer (A) according to the present invention has a number (n _a4 ) of structural units derived from the non-conjugated polyene (a4) per weight average molecular weight (Mw) of preferably 29 or less, more preferably 10 or less, and even more preferably less than 1.

In such copolymer (A), the content of structural units derived from non-conjugated polyene (a4) such as ENB is controlled within a range that does not impair the object of the present invention, and it is difficult for post-crosslinking to occur and has sufficient heat aging resistance.

Here, the number (n _a3 ) of structural units derived from non-conjugated polyene (a3) or the number (n _a4 ) of structural units derived from non-conjugated polyene (a4) per weight average molecular weight (Mw) of the copolymer (A) of the present invention can be calculated from the molecular weight of the non-conjugated polyene (a3) or (a4), the weight fraction of the structural units derived from the non-conjugated polyene (a3) or (a4) in the copolymer (weight fraction (wt %) of (a3) or (a4)), and the weight average molecular weight (Mw) of the copolymer (A) according to the following formula:

(n _a3 ) = (Mw) × {weight fraction of (a3)/100}/molecular weight of non-conjugated polyene (a3) (n _a4 ) = (Mw) × {weight fraction of (a4)/100}/molecular weight of non-conjugated polyene (a4) In the copolymer (A) of the present invention, when the numbers (n _a3 ) and (n a4 ) of structural units derived from non-conjugated polyenes (a3) and ( _a4 ) per weight average molecular weight (Mw) both satisfy the above ranges, the copolymer (A) has a low content of long chain branches, excellent curing characteristics when crosslinking is performed using a peroxide, good moldability, an excellent balance of physical properties such as mechanical properties, and is less likely to cause post-crosslinking, and is particularly excellent in heat aging resistance, which is preferable.

<<Method for producing ethylene/α-olefin/non-conjugated polyene copolymer (A)>>
The ethylene/α-olefin/non-conjugated polyene copolymer (A) according to the present invention is a copolymer obtained by copolymerizing monomers consisting of ethylene (a1), α-olefin (a2), non-conjugated polyene (a3), and, as necessary, non-conjugated polyene (a4).

The copolymer (A) according to the present invention may be prepared by any method as long as it satisfies the above requirements (i) to (iv). However, it is preferable that the copolymer (A) is prepared by copolymerizing monomers in the presence of a metallocene compound, and it is more preferable that the copolymer (A) is prepared by copolymerizing monomers in the presence of a catalyst system containing a metallocene compound.

As a specific method for producing the copolymer (A) according to the present invention, for example, it can be produced by adopting the production method using a metallocene catalyst described in JP-A-2018-119096 and WO 2015/122495.

Ethylene-α-olefin-non-conjugated polyene copolymer (B)
In addition to the copolymer (A), the copolymer composition of the present invention contains an ethylene/α-olefin/non-conjugated polyene copolymer (B) [hereinafter, sometimes abbreviated as "ethylene-based copolymer (B)."] which is an ethylene/α-olefin/non-conjugated polyene copolymer obtained by random copolymerization of ethylene (b1), an α-olefin (b2), and a non-conjugated polyene (b3).

The α-olefin (b2) constituting the ethylene-based copolymer (B) is usually an α-olefin having 3 to 20 carbon atoms, the same as the α-olefin (a2) constituting the copolymer (A) according to the present invention, and examples thereof include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-eicosene. Among these, α-olefins having 3 to 8 carbon atoms, such as propylene, 1-butene, 1-hexene, and 1-octene, are preferred, and propylene and 1-butene are particularly preferred. Such α-olefins are preferred because the raw material costs are relatively low, the resulting copolymer (B) exhibits excellent mechanical properties, and a molded article having rubber elasticity can be obtained.

The α-olefin (b2) constituting the copolymer (B) according to the present invention may be used alone or in combination of two or more. In other words, the copolymer (B) contains structural units derived from at least one type of α-olefin (b2) having 3 to 20 carbon atoms, and may contain structural units derived from two or more types of α-olefins (b2) having 3 to 20 carbon atoms.

The non-conjugated polyene (b3) constituting the copolymer (B) according to the present invention is a compound having two or more non-conjugated unsaturated bonds of the same category as the non-conjugated polyene (a4) constituting the copolymer (A) according to the present invention, and specifically, it is a non-conjugated polyene containing one partial structure selected from the group consisting of the above general formula (I) in the molecule. Specifically, the non-conjugated polyene (b3) is 5-ethylidene-2-norbornene (ENB), 5-methylene-2-norbornene, 5-(2-propenyl)-2-norbornene, 5-(3-butenyl)-2-norbornene, 5-(1-methyl-2-propenyl)-2-norbornene, 5-(4-pentenyl)-2-norbornene, 5-(1-methyl-3-butenyl)-2-norbornene, 5-(5-hexenyl)-2-norbornene, 5-(1-methyl-4-pentenyl)-2-norbornene, 5-(2,3-dimethyl-3-butenyl)-2-norbornene, 5-(2-ethyl-3-butenyl)-2-norbornene, 5-(6-heptenyl)-2-norbornene, 5-(3-methyl-5-hexenyl)-2-norbornene, 5-(3,4-dimethyl-4-pentenyl)-2-norbornene, 5-(3-ethyl 5-(7-octenyl)-2-norbornene, 5-(2-methyl-6-heptenyl)-2-norbornene, 5-(1,2-dimethyl-5-hexenyl)-2-norbornene, 5-(5-ethyl-5-hexenyl)-2-norbornene, 5-(1,2,3-trimethyl-4-pentenyl)-2-norbornene, etc. Among these, ENB is preferred because it is highly available, has high reactivity with sulfur and vulcanization accelerators during the crosslinking reaction after polymerization, is easy to control the crosslinking rate, and is easy to obtain good mechanical properties. The non-conjugated polyene (b3) may be used alone or in combination of two or more kinds.

The ethylene/α-olefin/non-conjugated polyene copolymer (B) of the present invention has a molar ratio of ethylene to α-olefin (ethylene/α-olefin) in the range of usually 40/60 to 90/10, preferably 50/50 to 80/20, and particularly preferably 55/45 to 70/30.

These non-conjugated polyenes (b3) are used alone or in combination of two or more, and the copolymerization amount is desirably 1 to 40, preferably 2 to 35, and more preferably 3 to 30, in terms of iodine value.

Among these non-conjugated polyenes, 5-ethylidene-2-norbornene (ENB) is preferred.
The ethylene/α-olefin/non-conjugated polyene copolymer (B) according to the present invention has an intrinsic viscosity [η] measured in decahydronaphthalene at 135° C. of preferably 0.1 to 5 dL/g, more preferably 0.5 to 5.0 dL/g, and even more preferably 0.9 to 4.0 dL/g.

The ethylene-α-olefin-non-conjugated polyene copolymer (B) of the present invention may be a modified product graft-copolymerized with an unsaturated carboxylic acid or a derivative thereof, such as an acid anhydride.

As the ethylene/α-olefin/non-conjugated polyene copolymer (B) according to the present invention, an ethylene/propylene/non-conjugated polyene copolymer is most preferred.
The ethylene/α-olefin/non-conjugated polyene copolymer (B) according to the present invention may be used alone or in combination of two or more. The ethylene/α-olefin/non-conjugated polyene copolymer (B) having the above-mentioned properties may be prepared by a known method such as that described in "Polymer Manufacturing Process" (published by Kogyo Chosakai Co., Ltd., pp. 309-330).

Carbon Black (C)
Carbon black (C), which is one of the components contained in the copolymer composition of the present invention, is a type of known rubber reinforcing agent that is compounded in rubber compositions, and is an inorganic substance generally known as carbon black.

Specific examples of carbon black (C) used in the present invention include Asahi #55G, Asahi #60G, and Asahi #60UG (all manufactured by Asahi Carbon Co., Ltd.), and Seast (V, SO, 116, 3, 6, 9, SP, TA, etc.) carbon blacks (manufactured by Tokai Carbon Co., Ltd.), and carbon blacks that have been surface-treated with a silane coupling agent, etc.

<<Fatty acid amide (D)>>
The fatty acid amide (D), which is one of the components contained in the copolymer composition of the present invention, is an amide of a higher fatty acid, and specific examples thereof include monoamides of higher fatty acids such as stearamide, oxystearoamide, oleylamide, erucic acid amide, laurylamide, palmitylamide, behenamide, and methylolamide; diamides of higher fatty acids such as methylene bis-stearoamide, ethylene bis-stearoamide, ethylene bis-oleylamide, and ethylene bis-laurylamide; complex amides of higher fatty acids such as stearyl oleylamide, N-stearyl erucamide, and N-oleyl palmitamide; and special fatty acids commercially available under the trade names Plastrodin ^™ (manufactured by Fujisawa Pharmaceutical Co., Ltd.) and Plastrodin S ^™ (manufactured by Fujisawa Pharmaceutical Co., Ltd.).

<<Inorganic filler (heavy calcium carbonate) (E)>>
Specific examples of the inorganic filler according to the present invention include light calcium carbonate, heavy calcium carbonate, talc, clay, and the like, and one or more of these are used. Among these, heavy calcium carbonate such as "Whiten SB" (product name; Shiraishi Calcium Co., Ltd.) is preferred.

<<Organic Peroxide (F)>>
The organic peroxide (F) according to the present invention includes dicumyl peroxide (DCP), di-tert-butyl peroxide, 2,5-di-(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexyne-3, 1,3-bis(tert-butylperoxyisopropyl)benzene, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butylperoxybenzoate, ert-butylperoxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, and tert-butylcumyl peroxide.

<Ethylene/α-olefin/non-conjugated polyene copolymer composition>
The copolymer composition of the present invention contains the copolymer (A) and, relative to 100 parts by mass of the copolymer (A), 20 to 300 parts by mass, preferably 30 to 300 parts by mass, and more preferably 50 to 250 parts by mass of the carbon black (C), 0.1 to 10 parts by mass, preferably 0.2 to 8 parts by mass, and more preferably 0.5 to 5 parts by mass of the fatty acid amide (D), 10 to 300 parts by mass, preferably 10 to 250 parts by mass, and more preferably 20 to 200 parts by mass of the inorganic filler (heavy calcium carbonate) (E), and 0.2 to 30 parts by mass, preferably 0.2 to 25 parts by mass, and more preferably 0.5 to 20 parts by mass of the organic peroxide (F).

The copolymer composition of the present invention contains, relative to 100 parts by mass of the copolymer (A) and the copolymer (B) and the total amount of the copolymer (A) and the copolymer, 20 to 300 parts by mass, preferably 30 to 300 parts by mass, and more preferably 50 to 250 parts by mass of carbon black (C), 0.1 to 10 parts by mass, preferably 0.2 to 8 parts by mass, and more preferably 0.5 to 5 parts by mass of the fatty acid amide (D), 10 to 300 parts by mass, preferably 10 to 250 parts by mass, and more preferably 20 to 200 parts by mass of the inorganic filler (heavy calcium carbonate) (E), and 0.2 to 30 parts by mass, preferably 0.2 to 25 parts by mass, and more preferably 0.5 to 20 parts by mass of the organic peroxide (F).

When the copolymer composition of the present invention contains the above-mentioned copolymer (A) and copolymer (B), the mass ratio of copolymer (A)/copolymer (B) (copolymer (A) + copolymer (B) = 100 parts by mass) is in the range of 95/5 to 5/95, preferably 90/10 to 10/90.

When the copolymer composition of the present invention contains the copolymer (B) in the above range, the resulting copolymer composition is (processable), and the molded article obtained by crosslinking the copolymer composition maintains its rigidity (modulus), while improving microcracks in the molded article and exhibiting excellent engine oil barrier properties.

In addition to the copolymer (A), the copolymer (B), the carbon black (C), the fatty acid amide (D), the inorganic filler (heavy calcium carbonate) (E) and the organic peroxide (F), the copolymer composition of the present invention may contain other components as necessary within a range that does not impair the effects of the present invention. Examples of other components include polymers, crosslinking agents, crosslinking assistants, vulcanization accelerators, vulcanization assistants, and inorganic fillers. At least one selected from softeners, antiaging agents (stabilizers), processing assistants, activators, moisture absorbents, heat stabilizers, weather stabilizers, antistatic agents, colorants, lubricants, and thickeners may be contained. Each of the polymers and additives may be used alone or in combination of two or more. Also, known foaming agents, foaming assistants, colorants, dispersants, flame retardants, and the like may be used as other components as necessary.

<Crosslinking aid, vulcanization accelerator and vulcanization aid>
Examples of the crosslinking aid include sulfur; quinone dioxime-based crosslinking aids such as p-quinone dioxime; acrylic crosslinking aids such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate; allyl crosslinking aids such as diallyl phthalate and triallyl isocyanurate; maleimide-based crosslinking aids; divinylbenzene; and metal oxides such as zinc oxide (e.g., ZnO#1/zinc oxide type 2 (JIS standard (K-1410)), manufactured by Hakusui Tech Co., Ltd.), magnesium oxide, and activated zinc oxide (e.g., zinc oxide such as "META-Z102" (trade name; manufactured by Inoue Seki Kogyo Co., Ltd.)).

When a crosslinking aid is used, the amount of the crosslinking aid in the copolymer composition is usually 0.5 to 10 moles, preferably 0.5 to 7 moles, and more preferably 1 to 6 moles, per mole of organic peroxide.

<Softener>
Specific examples of the softener according to the present invention include petroleum-based softeners such as process oil, lubricating oil, paraffin oil, liquid paraffin, petroleum asphalt, Vaseline, liquid ethylene-propylene copolymer, and liquid ethylene-1-butene copolymer; coal tar-based softeners such as coal tar; fatty oil-based softeners such as castor oil, linseed oil, rapeseed oil, soybean oil, and coconut oil; waxes such as beeswax and carnauba wax; fatty acids or salts thereof such as ricinoleic acid, palmitic acid, stearic acid, barium stearate, and calcium stearate; naphthenic acid, pine oil, rosin, and derivatives thereof; synthetic polymer substances such as terpene resins, petroleum resins, and coumarone-indene resins; ester-based softeners such as dioctyl phthalate and dioctyl adipate; and other microcrystalline waxes, liquid polybutadiene, modified liquid polybutadiene, hydrocarbon-based synthetic lubricating oils, tall oil, and sub (factice). Petroleum-based softeners are preferred, and process oils are particularly preferred.

The amount of the softener in the copolymer composition is generally 2 to 300 parts by mass, and preferably 10 to 250 parts by mass, per 100 parts by mass of copolymer (A) or the combined amount of copolymer (A) and copolymer (B).

<Anti-aging agent (stabilizer)>
The copolymer composition according to the present invention can be blended with an antioxidant (stabilizer) to extend the life of a molded article formed therefrom. Examples of such antioxidants include conventionally known antioxidants, such as amine-based antioxidants, phenol-based antioxidants, and sulfur-based antioxidants.

Further examples of antioxidants include aromatic secondary amine antioxidants such as phenylbutylamine and N,N-di-2-naphthyl-p-phenylenediamine; phenolic antioxidants such as dibutylhydroxytoluene and tetrakis[methylene(3,5-di-t-butyl-4-hydroxy)hydrocinnamate]methane; thioether antioxidants such as bis[2-methyl-4-(3-n-alkylthiopropionyloxy)-5-t-butylphenyl]sulfide; dithiocarbamate antioxidants such as nickel dibutyldithiocarbamate; and sulfur-based antioxidants such as 2-mercaptobenzoylimidazole, 2-mercaptobenzimidazole, zinc salt of 2-mercaptobenzimidazole, dilaurylthiodipropionate, and distearylthiodipropionate.

These antioxidants can be used alone or in combination of two or more, and the amount of the antioxidant is usually 0.3 to 10 parts by mass, and preferably 0.5 to 7.0 parts by mass, per 100 parts by mass of copolymer (A) or per 100 parts by mass of the total amount of copolymer (A) and copolymer (B). By keeping the amount within this range, no bloom occurs on the surface of the molded article obtained from the crosslinked product of the copolymer composition, and furthermore, the occurrence of crosslinking inhibition can be suppressed.

<Processing aids>
As the processing aid according to the present invention, a wide variety of processing aids that are generally compounded with rubber can be used.

Specific examples of processing aids include ricinoleic acid, stearic acid, palmitic acid, lauric acid, barium stearate, zinc stearate, calcium stearate, esters, etc. Of these, stearic acid is preferred.

The amount of the processing aid is usually 10 parts by mass or less, and preferably 8.0 parts by mass or less, per 100 parts by mass of copolymer (A) or the combined amount of copolymer (A) and copolymer (B) contained in the copolymer composition.

<Activator>
Specific examples of the surfactant include amines such as di-n-butylamine, dicyclohexylamine, and monoethanolamine; surfactants such as diethylene glycol, polyethylene glycol, lecithin, triaryl methylate, and zinc compounds of aliphatic or aromatic carboxylic acids; zinc peroxide preparations; octadecyltrimethylammonium bromide, synthetic hydrotalcite, and special quaternary ammonium compounds.

When an activator is included, the amount of the activator is usually 0.2 to 10 parts by mass, preferably 0.3 to 5 parts by mass, per 100 parts by mass of copolymer (A) or the total amount of copolymer (A) and copolymer (B).

<Moisture absorbent>
Specific examples of the moisture absorbent include calcium oxide, silica gel, sodium sulfate, molecular sieve, zeolite, and white carbon.

When a moisture absorbent is contained, the amount of the moisture absorbent is usually 0.5 to 15 parts by mass, and preferably 1.0 to 12 parts by mass, per 100 parts by mass of copolymer (A) or the combined amount of copolymer (A) and copolymer (B).

<Crosslinked Product of Copolymer Composition>
The crosslinked product of the copolymer composition of the present invention is obtained by crosslinking the above-mentioned copolymer composition of the present invention.
As a method for crosslinking the copolymer composition of the present invention, the copolymer composition is kneaded using a conventionally known kneading device, such as an open-type mixing roll, a closed-type Banbury mixer, an extruder, a kneader, a continuous mixer, etc. Among these, a closed-type kneading device is preferred, and kneading is preferably carried out in an atmosphere of an inert gas such as nitrogen gas or carbon dioxide gas.

<<Uses of the copolymer composition>>
The copolymer composition of the present invention can be molded by a commonly used molding method such as injection molding, extrusion molding, blow molding, compression molding, and the like. It is used in a wide range of applications, including automotive parts (clean side ducts, bellows-shaped hollow rubber products such as grommets, weather strips, ceiling materials, interior seats, bumper moldings, side moldings, air spoilers, air duct hoses, cup holders, handbrake grips, shift knob covers, seat adjustment knobs, flapper door seals, wire harness grommets, rack and pinion boots, suspension cover boots, glass guides, inner belt line seals, roof guides, trunk lid seals, molded quarter window gaskets, corner moldings, glass encapsulations, hood seals, glass run channels, secondary seals, clean side ducts, various packings, etc.), civil engineering and building material parts (waterstopping materials, joint materials, architectural window frames, etc.), sporting goods (golf clubs, tennis racket grips, etc.), industrial parts (hose tubes, gaskets, etc.), home appliance parts (hoses, packings, etc.), medical equipment parts, electric wires, and miscellaneous goods.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.
In the examples and comparative examples, the following copolymers were used.

(1) Ethylene/α-olefin/non-conjugated polyene copolymer (A)
As the ethylene/α-olefin/non-conjugated polyene copolymer (A), the ethylene/propylene/non-conjugated polyene copolymer (A-1) obtained in Production Example 1 was used.

[Production Example 1] Production of ethylene-propylene-non-conjugated polyene copolymer (A-1) Using a 300L volume polymerization vessel equipped with an agitator, a polymerization reaction of ethylene, propylene, and 5-vinyl-2-norbornene (VNB) was continuously carried out at 87°C. Hexane (feed rate: 32.6L/h) was used as the polymerization solvent, and the ethylene feed rate was continuously 3.6kg/h, the propylene amount was 6.1kg/h, the VNB feed rate was 290g/h, and the hydrogen feed rate was 6.3NL/h. While maintaining the polymerization pressure at 1.6MPaG and the polymerization temperature at 87°C, di(p-tolyl)methylene(cyclopentadienyl)(octamethyloctahydrodibenzofluorenyl)zirconium dichloride was used as the main catalyst, and the feed rate was continuously 0.0015mmol/h. Furthermore, (C ₆ H ₅ ) ₃ CB(C ₆ F ₅ ) ₄ as a cocatalyst was continuously fed at a feed rate of 0.0075 mmol/h, and triisobutylaluminum (TIBA) as an organoaluminum compound was continuously fed at a feed rate of 20 mmol/h to the polymerization reactor.

In this way, a solution containing 15.2% by mass of ethylene-propylene-VNB copolymer formed from ethylene, propylene and VNB was obtained. A small amount of methanol was added to the polymerization reaction liquid extracted from the bottom of the polymerization vessel to terminate the polymerization reaction, and the ethylene-propylene-VNB copolymer was separated from the solvent by steam stripping, and then dried under reduced pressure at 80°C overnight.

By the above operations, ethylene-propylene-VNB copolymer (A-1) formed from ethylene, propylene and VNB was obtained at a rate of 4.7 kg per hour. The physical properties of the obtained copolymer (A-1) were measured by the method described above. The results are shown in Table 1.

(2) Ethylene/α-olefin/non-conjugated polyene copolymer (B)
As the ethylene-α-olefin-non-conjugated polyene copolymer (B), an ethylene-propylene-ethylidenenorbornene (ENB) copolymer (B-1) was used.
Mitsui Chemicals, Inc. Product name: Mitsui EPT 3072EM (Mooney viscosity (ML(1+4) 125°C): 51, ethylene content: 64% by weight, ENB content: 5.4% by weight, oil extension amount: 40 phr)

[Physical Properties of Uncrosslinked Copolymer Composition]
(Mooney Viscosity (ML(1+4)100°C))
The Mooney viscosity at 100°C (ML(1+4)100°C) was measured at 100°C using a Mooney viscometer (SMV202 model, manufactured by Shimadzu Corporation) in accordance with JIS K6300.

(Mooney Scorch (Vm, t5; 145°C))
The Mooney scorch was measured in accordance with JIS K6300 using a Mooney viscometer (Model SMV202, manufactured by Shimadzu Corporation) at 145°C.

(Vulcanization speed)
Using the copolymer compositions (before crosslinking) in the examples and comparative examples, the scorch time (TS1) and vulcanization rate (TC90) were measured as follows using a measuring device: MDR2000P (manufactured by ALPHA TECHNOLOGIES) under the measurement conditions of a temperature of 170°C and a time of 20 minutes.

The sample was set in the measuring device, and the torque change obtained under the conditions of a constant temperature and a constant shear rate was measured to obtain a vulcanization curve. The minimum torque value _S'Min and the maximum torque value _S'Max were obtained from the vulcanization curve, and the time until the torque increased by 1 point from the start of the measurement was defined as TS1, and the time until the torque reached ( _S'Max - _S'Min ) x 0.9 was defined as the vulcanization speed (TC90; min).

<Physical properties of molded body (crosslinked product)>
(Tensile stress at break, tensile elongation at break)
The tensile stress at break and the tensile elongation at break of the sheet were measured by the following method.

The sheet was punched out to prepare No. 3 dumbbell test pieces as described in JIS K 6251 (1993). Using these test pieces, tensile tests were carried out according to the method specified in JIS K6251, paragraph 3, at a measurement temperature of 25°C and a tensile speed of 500 mm/min, and the modulus at 100% elongation (M100), tensile stress at break (TB), and tensile elongation at break (EB) were measured.

(Durometer A hardness)
In accordance with JIS K 6253, the hardness of the sheet (type A durometer, HA) was measured using six 2 mm sheet-like rubber molded products with smooth surfaces, with the flat parts stacked to a thickness of approximately 12 mm. However, test pieces containing foreign matter, air bubbles, or scratches were not used. The dimensions of the measurement surface of the test piece were set so that measurements could be made with the tip of the indenter at a position 12 mm or more away from the end of the test piece.

(Engine oil barrier test)
1. 1.8 g of NISSAN Engine Oil SN Strong Save X-OW20 (trade name) was added to a 2 mm thick sheet folded into a cylindrical stainless steel container with a diameter of 10 cm and a height of 10 cm.
2. Close the lid and heat in an oven at 130℃.
3. After 24 hours, the presence or absence of oil penetration and the state of oil adhesion on the sheet surface were checked and evaluated using the following scale.

Rating 4: No oil penetration.
Score 3: Oil seeps through; visual confirmation not possible; oil sticks to hands when touched.
Score 2: Oil penetration; visible; oil adhesion.
Score 1: Oil penetration; visible; drops visible.

(Injection moldability)
Using an injection molding die, the ethylene-α-olefin-non-conjugated polyene copolymer composition (blended material 2) obtained in the Examples and Comparative Examples was injected at a die temperature of 170° C., and held for 10 minutes to obtain a round bellows-shaped pipe.

The injection-molded round bellows-like pipe had a length of 100 mm, an outer diameter of 120 mm, a wall thickness of 2 mm, a pitch between bellows peaks of 15 mm, and a depth from peak to valley of bellows of 10 mm.
The molded round bellows-like pipe was removed from the mold and the appearance of the round bellows-like pipe was observed. If there was any crack in the bellows portion, it was judged as "present"; if there was no crack at all, it was judged as "absent."

Example 1
Using a MIXTRON BB MIXER (manufactured by Kobe Steel, Ltd., BB-4 type, volume 2.95 L, rotor 4WH), 80 parts by mass of copolymer (A-1) obtained in Production Example 1 and 28 parts by mass of copolymer (B-1) (containing 8 parts by mass of oil extension) in a total amount of 108 parts by mass [copolymer (A-1) + copolymer (B-1) = 100 parts by mass] were mixed with 5 parts by mass of active zinc oxide (product name Meta Z102, manufactured by Inoue Lime Industries Co., Ltd.) as a crosslinking aid, 2 parts by mass of stearic acid as a processing aid, 169 parts by mass of carbon black (product name Asahi #60UG, manufactured by Asahi Carbon Co., Ltd.), 100 parts by mass of calcium bicarbonate (product name Whiten SB, manufactured by Bihoku Powder Industry Co., Ltd.), paraffin-based process oil (product name Diana Process Oil PW-100) as a softener, and 111 parts by mass of a phenolic antioxidant (product name: Irganox 1010 manufactured by BASF Japan Ltd.) as an antiaging agent, 1 part by mass of 2-mercaptobenzimidazole (product name: Sandant MB manufactured by Sanshin Chemical Industry Co., Ltd.) as an antiaging agent, and 2 parts by mass of fatty acid amide (product name: Struktol WB16: calcium soap & saturated fatty acid amide mixture manufactured by S&S Japan Co., Ltd.) as a lubricant were blended and kneaded to obtain Blend 1.

The kneading conditions for preparing Compound 1 were a rotor rotation speed of 50 rpm, a floating weight pressure of 3 kg/cm ² , a kneading time of 5 minutes, and a kneading discharge temperature of 170°C.
The Mooney viscosity ML(1+4) 100° C. of Blend 1 was measured using a Mooney viscometer (Shimadzu Corporation, Model SMV202) in accordance with JIS K6300 (1994).

Next, after confirming that the temperature of Compound 1 had reached 40°C, 18.5 parts by mass of 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane (product name Perhexa 25B-40 (purity: 40%), manufactured by Nippon Oil & Fats Co., Ltd.) was added as a crosslinking agent to Compound 1 and kneaded using a 6-inch roll to obtain Compound 2.

The kneading conditions for preparing compound 2 were: roll temperature front roll/rear roll = 50°C/50°C, roll peripheral speed front roll/rear roll = 18 rpm/15 rpm, roll gap 2 mm, and kneading time 8 minutes to obtain compound 2.

Blend 2 was pressed at 170° C. for 10 minutes using a press molding machine to produce a crosslinked sheet having a thickness of 2 mm. The physical properties of the resulting crosslinked sheet were evaluated by the methods described above.
The evaluation results are shown in Table 2.

[Comparative Examples 1 to 3]
A crosslinked sheet was obtained in the same manner as in Example 1, except that the calcium bicarbonate blended in Example 1 was not blended, the other blending ingredients were blended in the amounts shown in Table 1, and 12.5 parts by mass of dicumyl peroxide (trade name: Percumyl D-40 (dicumyl peroxide 40% by mass), manufactured by NOF Corporation) was blended in place of the 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane used in Example 1.
The physical properties of the resulting crosslinked sheet were evaluated by the methods described above. The evaluation results are shown in Table 1.

Comparative Example 4
A crosslinked sheet was obtained in the same manner as in Example 1, except that in the formulation of Comparative Example 3, 18.5 parts by mass of 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane [product name Perhexa 25B-40 (purity: 40%), manufactured by Nippon Oil & Fats Co., Ltd.] was blended as a crosslinking agent.
The physical properties of the resulting crosslinked sheet were evaluated by the methods described above. The evaluation results are shown in Table 1.

Claims (4)

An ethylene/α-olefin/non-conjugated polyene copolymer (A) containing ethylene (a1), α-olefin (a2), and a non-conjugated polyene (a3) as structural units derived therefrom, and an ethylene/α-olefin/non-conjugated polyene copolymer (B) containing ethylene (b1), α-olefin (b2), and a non-conjugated polyene (b3) as structural units derived therefrom, wherein the total amount of the copolymers (A) and (B) is 100 parts by mass, and the copolymers (A) and (B) contain 20 to 300 parts by mass of carbon black (C), 0.1 to 10 parts by mass of fatty acid amide (D) , 10 to 300 parts by mass of heavy calcium carbonate ( E) , 0.2 to 30 parts by mass of organic peroxide (F) , and 111 to 300 parts by mass of a softener ,
the non-conjugated polyene (a3) constituting the ethylene/α-olefin/non-conjugated polyene copolymer (A) contains, in the molecule, a total of two or more partial structures selected from the group consisting of the following general formulas (I) and (II), and the ethylene/α-olefin/non-conjugated polyene copolymer (A) satisfies the following conditions (i) to (v):
The non-conjugated polyene (b3) constituting the ethylene/α-olefin/non-conjugated polyene copolymer (B) contains, in the molecule, one partial structure selected from the group consisting of the following general formula (I):
The fatty acid amide (D) is a saturated fatty acid amide,
The organic peroxide (F) is 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane.
The ethylene/α-olefin/non-conjugated polyene copolymer composition is characterized in that
(i) the molar ratio of the structural units derived from ethylene (a1) to the structural units derived from the α-olefin (a2) [(a1)/(a2)] is 40/60 to 99.9/0.1;
(ii) the content of the structural unit derived from the non-conjugated polyene (a3) is 0.07 to 10% by weight, relative to 100% by weight of the total of the structural units of (a1), (a2) and (a3);
(iii) the weight average molecular weight (Mw) of the ethylene/α-olefin/non-conjugated polyene copolymer (A), the weight fraction of the structural unit derived from the non-conjugated polyene (a3) (weight fraction (wt %) of (a3)), and the molecular weight of the non-conjugated polyene (a3) (molecular weight of (a3)) satisfy the following formula (1);
4.5≦Mw×weight fraction of (a3)/100/molecular weight of (a3)≦40 (1)
(iv) the ratio P(η*(ω=0.1)/η*(ω=100)) of the complex viscosity η*(ω=0.1) (Pa sec) at a frequency ω=0.1 rad/s to the complex viscosity η*(ω=100) (Pa sec) at a frequency ω=100 rad/s, which are obtained by linear viscoelasticity measurement (190° C.) using a rheometer, the intrinsic viscosity [η], and the weight fraction of the structural unit derived from the non-conjugated polyene (a3) (weight fraction of (a3)) satisfy the following formula (2);
P / ([η] ^2.9 ) ≦ weight fraction of (a3) × 6 (2)
(v) The number of long chain branches per 1,000 carbon atoms (LCB _1000C ) and the natural logarithm of the weight average molecular weight (Mw) [Ln(Mw)], both obtained using 3D-GPC, satisfy the following formula (3):
LCB _1000C ≦1−0.07×Ln(Mw) … (3)

The ethylene/α-olefin/non-conjugated polyene copolymer composition according to claim 1 , characterized in that the non-conjugated polyene (a3) constituting the ethylene/α-olefin/non-conjugated polyene copolymer (A) contains 5-vinyl-2-norbornene (VNB). A crosslinked molded article comprising the ethylene/α-olefin/non-conjugated polyene copolymer composition according to claim 1 or 2 . 4. The crosslinked molding according to claim 3 , which is a bellows-shaped hollow body.