JP2014114379A - ETHYLENE/α-OLEFIN/NON-CONJUGATED POLYENE COPOLYMER COMPOSITION, CROSSLINKED FOAM OBTAINED FROM THE COMPOSITION, AND METHOD FOR MANUFACTURING THE SAME - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crosslinked foam having a low specific gravity and a high rigidity.SOLUTION: The provided ethylene/α-olefin/non-conjugated polyene copolymer composition includes 100 parts of an ethylene/α-olefin/non-conjugated polyene copolymer (A) satisfying requirements (1) through (3) and 30-160 parts of a filler (C) at a total mixing sum of at least 150 parts: (1) that the copolymer (A) contains structural units of: [A] ethylene; [B] a C3-20 α-olefin; [C-1] a non-conjugated polyene containing only one intramolecular partial structure of a cycloolefin of the formula (I) or partial structure of the formula (II) and [C-2] a non-conjugated polyene including at least two partial structures selected from between those of the formulae (I) and (II); (2) that the 100°C Mooney viscosity of the copolymer (A) satisfies the following: [ML(1+4)100°C]=20-45; and (3) that the copolymer (A) satisfies the following: Log[η(0.01)]/Log[η(10)]>0.0753×{apparent iodine value of units derived from [C-2]}+1.32 (η(0.01): viscosity at 190°C and 0.01 rad/sec (Pa sec); η(10): viscosity at 190°C and 10 rad/sec (Pa sec)).

Description

  The present invention relates to an ethylene / α-olefin / nonconjugated polyene copolymer composition, a crosslinked foam having a low specific gravity and sufficient rigidity obtained from the composition, and a method for producing the same.

  Since ethylene / propylene / diene copolymer rubber (EPDM) does not have a double bond in the main chain of its molecular structure, it is excellent in heat aging resistance, weather resistance, and ozone resistance compared to general-purpose conjugated diene rubber. Above all, EPDM foam is used as a cushioning material, pad material, sealing material such as airtightness and water stop, heat insulation material, soundproofing material, etc. based on its excellent cushioning property and compressibility, etc. It is widely used in various fields such as outdoor equipment such as houses and buildings such as houses.

  The weather strip sponge for automobiles, one of the typical uses of EPDM foam, is intended to prevent water, sound, and dust from entering the vehicle interior, reduce the impact when opening and closing the door, and prevent door vibration during travel. Used in car bodies, doors, trunks, etc. In recent years, there has been a strong demand for reducing the specific gravity of rubber foams from the viewpoint of saving materials and reducing weight. However, there is a problem that the sealing performance deteriorates with a decrease in specific gravity, and the surface smoothness is impaired. As a method for coping with these problems, for example, a method of increasing the rigidity by adding a crystalline polyolefin resin to a compound and a method of increasing the hardness by increasing the amount of filler have been studied.

  For example, Patent Document 1 discloses a method of obtaining a foamed product having a low specific gravity by blending a crystalline polyolefin resin. However, in the method of blending the crystalline polyolefin, the rigidity at normal temperature is improved, but the rubber elasticity at a low temperature tends to be lowered.

  On the other hand, Patent Literature 2 and Patent Literature 3 disclose foamed molded articles having increased hardness by increasing the amount of filler. However, the method of increasing the amount of filler tends to increase the viscosity of the uncrosslinked compound and reduce the processability of the compound. Moreover, in order to improve workability, it is necessary to increase the amount of plasticizer, but in that case, the expected rigidity cannot be obtained.

JP 2000-344980 A JP 2012-052032 A JP 2001-0772816 A

  The present invention has been made in view of the above problems. That is, an object of the present invention is to provide a polymer composition having sufficiently high foamability, and a crosslinked foam having a low specific gravity and sufficient rigidity as, for example, a sealing material, obtained by crosslinking and foaming the polymer composition. Is to provide.

  As a result of intensive studies to achieve the above object, the present inventors have found that ethylene / α-olefin / non-conjugated diene random copolymers having a low Mooney viscosity and a large amount of long-chain branches uniformly and carbon black, Cross-linked foam (foamed rubber molded product) obtained from a polymer composition containing a certain amount of filler (reinforcing filler) such as low specific gravity and rigidity, and exhibits good rubber elasticity even at low temperatures. The headline and the present invention were completed.

That is, the present invention contains 100 parts by mass of an ethylene / α-olefin / non-conjugated polyene copolymer (A) satisfying the following requirements (1) to (3) and 30 to 160 parts by mass of a filler (C). And an ethylene / α-olefin / non-conjugated polyene copolymer composition (X) having a total blending part of 150 parts by mass or more.
(1) The ethylene / α-olefin / non-conjugated polyene copolymer (A) is ethylene [A], an α-olefin [B] having 3 to 20 carbon atoms, the following general formula (I) or (II): A non-conjugated polyene [C-1] containing only one partial structure represented in the molecule,

(However, (I) is a partial structure of cyclic olefin.)

And a structural unit derived from non-conjugated polyene [C-2] containing two or more partial structures selected from the group consisting of general formulas (I) and (II) in the molecule.
(2) The Mooney viscosity [ML (1 + 4)] at 100 ° C. of the ethylene / α-olefin / non-conjugated polyene copolymer (A) is 20 to 45.
(3) The ethylene / α-olefin / non-conjugated polyene copolymer (A) satisfies the following formula (i).

Log {η ^* (0.01)} / Log {η ^* (10)}> 0.0753 × {apparent iodine value derived from non-conjugated polyene [C-2]} + 1.32 (i)
(Where η ^* (0.01) represents a viscosity (Pa · sec) of 0.01 rad / sec at 190 ° C., and η ^* (10) represents a viscosity (Pa · sec of 10 rad / sec at 190 ° C. ).

  Further, the present invention is a crosslinked foam (Y) obtained by crosslinking and foaming the above-mentioned ethylene / α-olefin / non-conjugated polyene copolymer composition (X).

  Furthermore, the present invention is a method for producing a crosslinked foam, wherein the above-mentioned ethylene / α-olefin / non-conjugated polyene copolymer composition (X) is crosslinked and foamed.

  Furthermore, the present invention is a weather strip sponge obtained from the above-mentioned ethylene / α-olefin / non-conjugated polyene copolymer (X).

  Furthermore, the present invention is a method for producing a weatherstrip sponge, characterized in that the above-mentioned ethylene / α-olefin / non-conjugated polyene copolymer composition (X) is crosslinked and foamed.

  Further, according to the present invention, the specific gravity is 0.3 to 0.5, and the low tensile stress (σ25) is 0, using a composition containing an ethylene / α-olefin / non-conjugated polyene copolymer and a filler. It is a weather strip sponge which is .15 to 0.35 MPa.

  Since the polymer composition (X) of the present invention contains a specific ethylene / α-olefin / non-conjugated polyene copolymer (A), the polymer composition (X) is heavy even if a relatively large amount of the filler (C) is blended. The viscosity of the combined composition (X) as a whole is moderate, and there is no problem in processability. Therefore, even if a relatively large amount of filler (C) is blended, the rigidity can be increased without causing a problem in workability. Furthermore, since the gas retainability at the time of foam molding is good, the specific gravity can be reduced, and the good shape retainability is exhibited without impairing the surface smoothness.

[Ethylene / α-olefin / non-conjugated polyene copolymer (A)]
The ethylene / α-olefin / non-conjugated polyene copolymer (A) used in the present invention is characterized by satisfying the requirements (1) to (3) described below.

[Requirement (1)]
The requirement (1) is that the ethylene / α-olefin / non-conjugated polyene copolymer (A) is ethylene [A], an α-olefin [B] having 3 to 20 carbon atoms, the following general formula (I) or ( II) a non-conjugated polyene [C-1] containing only one partial structure represented by

(However, (I) is a partial structure of cyclic olefin.)

And it is that the structural unit derived from the nonconjugated polyene [C-2] which contains two or more in total in the molecule | numerator the partial structure chosen from the group which consists of general formula (I) and (II) is included.

The molar ratio of the structural units derived from ethylene [A] is preferably 44 to 89 mol%, more preferably 50 to 74 mol%, in 100 mol% of all structural units of the copolymer (A). This molar ratio can be determined by ¹³ C-NMR.

  Examples of the α-olefin [B] having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene and 1-octene. Examples include decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-eicocene. Of these, α-olefins having 3 to 8 carbon atoms such as propylene, 1-butene, 1-hexene and 1-octene are particularly preferable. Such an α-olefin is preferable because the raw material cost is relatively low and the resulting copolymer exhibits excellent mechanical properties.

  In addition, the copolymer used for this invention contains the structural unit derived from an at least 1 sort (s) of C3-C20 alpha-olefin [B], and is 2 or more types of C3-C20 alpha. -The structural unit derived from olefin [B] may be included.

The molar ratio of the structural units derived from the α-olefin [B] having 3 to 20 carbon atoms is preferably 10 to 50 mol%, more preferably 100 mol%, more preferably 100 mol% of all structural units of the copolymer (A). Is 25 to 45 mol%. These ranges are suitable from the viewpoint of the flexibility of the crosslinked foam and the mechanical properties at low temperatures. This molar ratio can be determined by ¹³ C-NMR.

The non-conjugated polyene [C-1] containing only one partial structure represented by the general formula (I) or (II) in the molecule has, for example, vinyl groups (CH ₂ ═CH—) at both ends of the molecule. Aliphatic polyenes are not included. Specific examples of the non-conjugated polyene [C-1] include the following aliphatic polyenes and alicyclic polyenes.

  Specific examples of the aliphatic polyene include 1,4-hexadiene, 1,5-heptadiene, 1,6-octadiene, 1,7-nonadiene, 1,8-decadiene, 1,12-tetradecadiene, and 3-methyl. 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 4-ethyl-1,4-hexadiene, 3,3-dimethyl-1,4-hexadiene, 5 -Methyl-1,4-heptadiene, 5-ethyl-1,4-heptadiene, 5-methyl-1,5-heptadiene, 6-methyl-1,5-heptadiene, 5-ethyl-1,5-heptadiene, 4 -Methyl-1,4-octadiene, 5-methyl-1,4-octadiene, 4-ethyl-1,4-octadiene, 5-ethyl-1,4-octadiene, 5-methyl-1,5-octadiene, 6 -Methyl-1 , 5-octadiene, 5-ethyl-1,5-octadiene, 6-ethyl-1,5-octadiene, 6-methyl-1,6-octadiene, 7-methyl-1,6-octadiene, 6-ethyl-1 , 6-octadiene, 6-propyl-1,6-octadiene, 6-butyl-1,6-octadiene, 7-methyl-1,6-octadiene, 4-methyl-1,4-nonadiene, 5-methyl-1 , 4-nonadiene, 4-ethyl-1,4-nonadiene, 5-ethyl-1,4-nonadiene, 5-methyl-1,5-nonadiene, 6-methyl-1,5-nonadiene, 5-ethyl-1 , 5-nonadiene, 6-ethyl-1,5-nonadiene, 6-methyl-1,6-nonadiene, 7-methyl-1,6-nonadiene, 6-ethyl-1,6-nonadiene, 7-ethyl-1 , 6-nonadiene, 7-methyl-1,7 -Nonadiene, 8-methyl-1,7-nonadiene, 7-ethyl-1,7-nonadiene, 5-methyl-1,4-decadiene, 5-ethyl-1,4-decadiene, 5-methyl-1,5 -Decadiene, 6-methyl-1,5-decadiene, 5-ethyl-1,5-decadiene, 6-ethyl-1,5-decadiene, 6-methyl-1,6-decadiene, 6-ethyl-1,6 -Decadiene, 7-methyl-1,6-decadiene, 7-ethyl-1,6-decadiene, 7-methyl-1,7-decadiene, 8-methyl-1,7-decadiene, 7-ethyl-1,7 -Decadiene, 8-ethyl-1,7-decadiene, 8-methyl-1,8-decadiene, 9-methyl-1,8-decadiene, 8-ethyl-1,8-decadiene, 6-methyl-1,6 -Undecadiene, 9-methyl-1,8-undecadiene It is below. In the present invention, these aliphatic polyenes can be used singly or in combination of two or more. Preferably 7-methyl-1,6-octadiene is used.

  As the alicyclic polyene, for example, an alicyclic portion having one carbon / carbon double bond (unsaturated bond) and a carbon atom constituting the alicyclic portion are bonded by a carbon / carbon double bond. And a polyene composed of a chain portion (ethylidene, propylidene, etc.). Specific examples thereof include 5-ethylidene-2-norbornene (ENB), 5-propylidene-2-norbornene, and 5-butylidene-2-norbornene. In particular, 5-ethylidene-2-norbornene (ENB) is preferable. Examples of other alicyclic polyenes include 2-methyl-2,5-norbornadiene and 2-ethyl-2,5-norbornadiene.

  In addition, the copolymer used for this invention contains the structural unit derived from the at least 1 sort (s) of component [C-1], and contains the structural unit derived from 2 or more types of components [C-1]. Also good.

  Examples of the non-conjugated polyene [C-2] containing two or more partial structures selected from the group consisting of the general formulas (I) and (II) in the molecule include carbon / carbon double bonds (unsaturated bonds). ) And an alicyclic polyene having a chain portion containing a vinyl group and bonded to a carbon atom constituting the alicyclic portion, an aliphatic having a vinyl group at both ends of the molecule Polyene is mentioned. Specific examples thereof include 5-alkenyl-2-norbornene such as 5-vinyl-2-norbornene (VNB) and 5-allyl-2-norbornene; 2,5-norbornadiene, dicyclopentadiene (DCPD), norbornadiene, tetracyclo [4,4,0,12.5,17.10] Alicyclic polyenes such as deca-3,8-diene; fats such as α, ω-diene such as 1,7-octadiene and 1,9-decadiene Group polyenes. Among these, 5-vinyl-2-norbornene (VNB), 5-alkenyl-2-norbornene, dicyclopentadiene, 2,5-norbornadiene, 1,7-octadiene, and 1,9-decadiene are preferable, and 5-vinyl 2-norbornene (VNB) is particularly preferred.

  In addition, the copolymer used for this invention contains the structural unit derived from the at least 1 sort (s) of component [C-2], and contains the structural unit derived from 2 or more types of components [C-2]. Also good.

The sum of the molar ratio of the structural units derived from the non-conjugated polyene [C-1] and the molar ratio of the structural units derived from the non-conjugated polyene [C-2] is 100 mol% of all structural units of the copolymer (A). The content is preferably 1.0 to 6.0 mol%, more preferably 1.0 to 5.0 mol%. These ranges are suitable from the viewpoint of relatively easily controlling the vulcanization reaction rate. Further, the ratio ([C-1] / [C-2] of mol% of structural units derived from non-conjugated polyene [C-1] and mol% of structural units derived from non-conjugated polyene [C-2]. ) Is preferably 75/25 to 99.5 / 0.5, more preferably 78/22 to 97/3. These ranges are suitable from the viewpoint of a balance between vulcanization reactivity and gas retention during foaming reaction. These can be determined by ¹³ C-NMR.

  The following is obtained from ethylene, propylene, 5-ethylidene-2-norbornene (ENB) and 5-vinyl-2-norbornene (VNB) which are examples of the ethylene / α-olefin / non-conjugated polyene copolymer (A). A method for obtaining the molar ratio of the copolymer will be specifically described.

The structure (composition) analysis of ethylene, propylene and ENB copolymer by ¹³ C-NMR was conducted by CJ Carman, RA Harrington, and CE Wilkes, Macromolecules, 10, p 536-544 (1977), Masahiro Kakugo, Yukio. Structures of VNB copolymers based on Naito, Kooji Mizunuma, and Tatsuya, Miyatake, Macromolecules, 15, p 1150-1152 (1982) and G. Van der Velden, Macromolecules, 16, p 85-89 (1983) Analysis was carried out by Harris Lasarov, Tuula T. Pakkanen, Macromol. Rapid Commun., 20, p 356-360 (1999), and Harri Lasarov *, Tuula T. Pakkanen, Macromol. Rapid Commun., 22, p 434-438 ( 2001).

First, the integrated value of each peak derived from ethylene, propylene, ENB and VNB was determined by ¹³ C-NMR.

1) Ethylene; [Integral value of peak derived from ethylene chain + [Integral value of peak derived from ethylene-propylene chain] / 2]
2) Propylene; [Integral value of peak derived from propylene chain + [Integral value of peak derived from ethylene-propylene chain] / 2]
3) ENB; integral value of ENB-3 position peak 4) VNB; integral value of VNB-7 position peak Chemical formula of structure (E body, Z body) derived from ENB in the copolymer used in the present invention, and VNB The chemical formula of the derived structure (endo (n), exo (x)) is shown below.

  From the obtained integrated value ratio, the mol% of the structural unit derived from ENB and VNB was calculated. The conversion to wt% was carried out with the molecular weight of ethylene being 28.05, the molecular weight of propylene being 42.08, and the molecular weight of ENB and VNB being 120.2.

[Requirement (2)]
The requirement (2) is that the Mooney viscosity [ML (1 + 4)] at 100 ° C. of the ethylene / α-olefin / non-conjugated polyene copolymer (A) is 20 to 45. Further, the Mooney viscosity [ML (1 + 4)] at 100 ° C. is preferably 25 to 40. These ranges are suitable from the viewpoint that even if a relatively large amount of filler (C) is blended, no problem occurs in workability.

[Requirement (3)]
The requirement (3) is that the ethylene / α-olefin / non-conjugated polyene copolymer (A) satisfies the following formula (i).

Log {η ^* (0.01)} / Log {η ^* (10)}> 0.0753 × {apparent iodine value derived from non-conjugated polyene [C-2]} + 1.32 (i)
(Where η ^* (0.01) represents a viscosity (Pa · sec) of 0.01 rad / sec at 190 ° C., and η ^* (10) represents a viscosity (Pa · sec of 10 rad / sec at 190 ° C. )
The above formula (i) is derived from the non-conjugated polyene [C-2] in the copolymer (A) by measuring η ^* (0.01) and η ^* (10) with a viscoelasticity measuring device and by NMR. The apparent iodine value can be specifically calculated from the following formula by measuring the content (% by mass) of the structural unit. The molecular weight of iodine is 253.81.

Apparent iodine value derived from non-conjugated polyene [C-2] = [Content (% by weight) of structural unit derived from non-conjugated polyene [C-2]] × Y × 253.81 / Molecular weight of conjugated polyene [C-2]
(In the formula, Y represents the number of carbon-carbon double bonds contained in the structural unit derived from non-conjugated polyene [C-2].)
When the copolymer (A) is within the range defined by the above formula (i), the copolymer (A) has more long chain branches regardless of the small non-conjugated polyene [C-2] content. That is, long chain branching necessary for obtaining excellent shape retention and extrusion processability can be introduced by copolymerizing a small amount of non-conjugated polyene [C-2], and residual non-conjugated polyene [C- 2] The rubber molded body obtained because of its low content is excellent in compression set. If it is outside the range defined by the above formula (i), long chain branching that affects shape retention and foaming properties is introduced into the copolymer rubber, so that a large amount of non-conjugated polyene [C-2] Need. As a result, heat aging resistance and rubber elasticity are deteriorated, and excellent sponge performance and product yield are remarkably impaired by the formation of foreign matters due to gelation.

[Polymerization catalyst]
The copolymer (A) used in the present invention is preferably a copolymer synthesized using a metallocene catalyst. As the metallocene catalyst, a catalyst represented by the following formula (IA), (IIA) or (IIIA) is preferable.

  The compound represented by formula (IA) will be described.

In formula (IA), each R is independently a group or hydrogen atom selected from hydrocarbyl, halohydrocarbyl, silyl, germyl and combinations thereof, and the number of atoms other than hydrogen contained in the group is 20 or less. It is.
M is titanium, zirconium or hafnium.
Y is -O-, -S-, -NR ^* -or -PR ^* -. R ^* is a hydrogen atom, hydrocarbyl group, hydrocarbyloxy group, silyl group, halogenated alkyl group or halogenated aryl group, and when R ^* is not hydrogen, R ^* represents up to 20 non-hydrogen atoms. contains.
Z is a divalent group containing boron or a group 14 element and containing nitrogen, phosphorus, sulfur or oxygen, and the divalent group has 60 or less atoms other than hydrogen atoms. is there.
X is independently an anionic ligand having 60 or less atoms when a plurality of X are present (excluding a cyclic ligand in which π electrons are delocalized).
X ′ is a neutral linking compound having 20 or less atoms, independently when there are a plurality of X ′.
p is 0, 1 or 2;
q is 0 or 1.

  However, when p is 2 and q is 0, M is in the +4 oxidation state, X is halide, hydrocarbyl, hydrocarbyloxy, di (hydrocarbyl) amide, di (hydrocarbyl) phosphide, hydrocarbyl sulfide, silyl group, An anionic ligand selected from halo-substituted derivatives, di (hydrocarbyl) amino-substituted derivatives, hydrocarbyloxy-substituted derivatives and di (hydrocarbyl) phosphino-substituted derivatives, and the number of atoms other than hydrogen atoms in X is 20 or less . And when p is 1 and q is 0, M is in the +3 oxidation state, X is allyl, 2- (N, N′-dimethylaminomethyl) phenyl and 2- (N, N′-dimethyl) amino. It is an anionic stabilizing ligand selected from benzyl, or M is in the +4 oxidation state, and X is a divalent conjugated diene derivative to form M and a metallacyclopentene. When p is 0 and q is 1, M is in the +2 oxidation state, X ′ is a neutral conjugated or nonconjugated diene which may be substituted with one or more hydrocarbyl groups, and has 40 carbon atoms. It is contained in a number of 1 or less and forms a π complex with M.

  The compound represented by formula (IIA) will be described.

In formula (IIA), R ¹ and R ² are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and at least one of R ¹ and R ² is not a hydrogen atom.
R ^{3 to} R ⁶ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. R ^{1 to} R ⁶ may be bonded to each other to form a ring.
M is titanium.
Y is -O-, -S-, -NR ^* -or -PR ^* -.
Z ^{* _{is, SiR * 2, CR * 2}} , SiR * 2 SiR * 2, CR * 2 CR * 2, CR * = CR *, a CR ^* ₂ SiR ^* _2, or GeR ^* _2. Each R ^* is independently a hydrogen atom, hydrocarbyl group, hydrocarbyloxy group, silyl group, halogenated alkyl group or halogenated aryl group, and when R ^* is not hydrogen, R ^* is up to 20 hydrogen atoms; Contains atoms other than. Z two binding of the ^* R ^* (when R ^* is not hydrogen) may also form a ring, R ^* binding to R ^* and Y bonded to Z ^* may form a ring.
p is 0, 1 or 2;
q is 0 or 1.

  However, when p is 2, q is 0, M is in a +4 oxidation state, and X is independently a methyl group or a benzyl group. When p is 1, q is 0, M is in an oxidation state of +3, X is a 2- (N, N′-dimethyl) aminobenzyl group, or q is 0, and M is In the +4 oxidation state, X is 1,3-butadienyl. When p is 0, q is 1, M is in the +2 oxidation state, and X is 1,4-diphenyl-1,3-butadiene, 2,4-hexadiene, or 1,3-pentadiene.

  The compound represented by formula (IIIA) will be described.

In formula (IIIA), R ′ is a hydrogen atom, a hydrocarbyl group, a di (hydrocarbylamino) group, or a hydrocarbyleneamino group, and when R ′ has a carbon atom, the number of carbon atoms is 20 or less.
R ″ is a hydrocarbyl group having 1 to 20 carbon atoms or a hydrogen atom.
M is titanium.
Y is, -O -, - S -, - NR * -, - PR * -, - NR 2 *, or -PR ₂ ^*.
Z ^{* _{is, -SiR * 2 -, - CR}} * 2 -, - SiR * 2 SiR * 2 -, - CR * 2 CR * 2 -, - CR * = CR * -, - CR * 2 SiR * 2 - Or -GeR ^* _2- . R ^* is independently a hydrogen atom or a group containing at least one selected from the group consisting of hydrocarbyl, hydrocarbyloxy, silyl, alkyl halide, and aryl halide, when there are a plurality of R ^* , R ^* contains an atom of up to atomic number 2-20, two with the optionally Z ^* R ^* (when R ^* is not hydrogen atom) may form a ring, the Z ^* of R ^* and Y R ^* may form a ring.
X is a monovalent anionic ligand having 60 or less atoms, excluding the cyclic ligand in which π electrons are delocalized.
X ′ is a neutral linking group having 20 or less atoms.
X ″ is a divalent anionic ligand having 60 or less atoms.
p is 0, 1 or 2;
q is 0 or 1.
r is 0 or 1;

When p is 2, q and r are 0 and M is an oxidation state of +4 (except when Y is -NR ^* ₂ or -PR ^* ₂ ), or M is an oxidation state of +3 (provided that , Y is —NR ^* ₂ or —PR ^* ₂ , and X is a halide group, hydrocarbyl group, hydrocarbyloxy group, di (hydrocarbyl) amide group, di (hydrocarbyl) phosphide group, hydrocarbyl sulfide group, and silyl Groups, as well as groups in which these groups are halogen substituted, groups in which these groups are di (hydrocarbyl) amino substituted, groups in which these groups are hydrocarbyloxy substituted and groups in which these groups are di (hydrocarbyl) phosphino substituted An anionic ligand selected from the group consisting of the above groups, wherein the group comprises atoms having atomic numbers from 2 to 30.

  When r is 1, p and q are 0, M is an oxidation state of +4, and X ″ is a dianion selected from the group consisting of a hydrocarbazyl group, an oxyhydrocarbyl group, and a hydrocarbylene dioxy group X ″ has an atom number of 2 to 30. When p is 1, q and r are 0, M is the oxidation state of +3, X is allyl, 2- (N, N-dimethylamino) phenyl, 2- (N, N-dimethylaminomethyl) ) An anionic stabilizing ligand selected from the group consisting of phenyl and 2- (N, N-dimethylamino) benzyl. When p and r are 0, q is 1, M is in the +2 oxidation state, and X ′ is a neutral conjugated diene or neutral diconjugated, optionally substituted with one or more hydrocarbyl groups It is a diene, and the X ′ has a carbon atom number of 40 or less and forms a bond with M by π-π interaction.

  In a more preferred embodiment, in formula (IIIA), when p is 2 and q and r are 0, M is in the +4 oxidation state, and X is each independently methyl, benzyl, or halide. Yes, when p and q are 0, r is 1, M is in the +4 oxidation state, X ″ is a 1,4-butadienyl group that forms a metallacyclopentene ring with M, and p is When 1, q and r are 0, M is in the +3 oxidation state, X is 2- (N, N-dimethylamino) benzyl, and when p and r are 0, q is 1, M is the +2 oxidation state, and X ′ is 1,4-diphenyl-1,3-butadiene or 1,3-pentadiene.

  Of the formula (IIIA), a compound represented by the following formula (IIIA ′) is particularly preferable.

In the formula (IIIA ′), R ′ is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, R ″ is a hydrocarbyl group or hydrogen atom having 1 to 20 carbon atoms, M is titanium, Y Is —NR ^* —, Z ^* is —SiR ^* ₂ —, R ^* is independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and one of p and q Is 0, the other is 1, p is 0 and q is 1, M is in the +2 oxidation state and X ′ is 1,4-diphenyl-1,3-butadiene or 1, When 3-pentadiene, p is 1 and q is 0, M is in the +3 oxidation state and X is 2- (N, N-dimethylamino) benzyl.

  Examples of the hydrocarbyl group having 1 to 20 carbon atoms include linear alkyl groups such as a methyl group, an ethyl group, and a butyl group, and branched alkyl groups such as a t-butyl group and a neopentyl group. Examples of the hydrocarbyloxy group include linear alkyloxy groups such as methyloxy group, ethyloxy group and butyloxy group, and branched alkyloxy groups such as t-butyloxy group and neopentyloxy group. Examples of the halogenated alkyl group include those obtained by chlorinating, brominating, or fluorinating the linear alkyl group or the branched alkyl group. Examples of the halogenated aryl group include a chlorinated phenyl group and a chlorinated naphthyl group.

  In formula (III′A), R ″ is preferably a hydrogen atom or methyl, and more preferably methyl.

Particularly preferred catalysts are (t-butylamido) dimethyl (η ⁵ -2-methyl-s-indasen-1-yl) silane titanium (II) 2,4-hexadiene (IV), (t-butylamido) -dimethyl (η ^5-methyl -s- indacene-1-yl) silane - titanium (IV) dimethyl (V), (t-butylamido) - dimethyl (eta ^{5-2,3-dimethyl} indenyl) silane titanium (II) 1 , 4-Diphenyl-1,3-butadiene (VI), (t-butyl-amido) -dimethyl (η ⁵ -2,3-dimethyl-s-indasen-1-yl) silane titanium (IV) dimethyl (VII) , (T-Butylamido) -dimethyl (η ⁵ -2-methyl-s-indasen-1-yl) silane titanium (II) 1,3-pentadiene (VIII). Among them, (t-butylamido) -dimethyl (η ⁵ -2-methyl-s-indacene-1-yl) silane titanium (II) 1,3-pentadiene (VIII) is particularly preferable.

  In particular, when a catalyst having a structure represented by the above formula (VIII) is used, the polymerization reaction for obtaining the copolymer (A) used in the present invention is carried out by using a non-conjugated polyene (component [C-1] and component [C-1]. -2]) is excellent in copolymer properties, and for example, a double bond at the VNB end can be efficiently incorporated, and long-chain branching can be introduced at a high rate. Moreover, since the molecular weight distribution and composition distribution of the obtained copolymer (A) are narrow and a copolymer having a very uniform molecular structure can be prepared, there is a concern that rubber molding is concerned with the generation of long-chain branches. The formation of gel-like irregularities on the body surface is significantly suppressed. As a result, a rubber molded product comprising such a copolymer is excellent in surface appearance because it does not contain gel-like particles, and also has excellent production stability because of excellent shape retention.

  These catalysts can be prepared using well-known synthetic techniques. For example, it is disclosed in International Publication WO98 / 49212.

<Method for producing ethylene / α-olefin / non-conjugated polyene copolymer (A)>
When synthesizing the ethylene / α-olefin / non-conjugated polyene copolymer (A) used in the present invention, a metallocene catalyst, preferably a catalyst having the structure exemplified above is preferably used. For example, a continuous method or a batch method using a catalyst with a stirrer as a main catalyst, an organoaluminum compound such as a boron compound and / or a trialkyl compound as a cocatalyst, an aliphatic hydrocarbon such as hexane as a solvent, and the like. Thus, the copolymer (A) can be obtained.

  The reaction temperature can be raised to 100 ° C. because the catalyst is not deactivated even at high temperatures. The polymerization pressure is more than 0 to -8 MPa (gauge pressure), preferably more than 0 to -5 MPa (gauge pressure). The reaction time (average residence time when copolymerization is carried out in a continuous process) varies depending on conditions such as catalyst concentration and polymerization temperature, but is usually 0.5 minutes to 5 hours, preferably 10 minutes to 3 hours. It is. In the copolymerization, a molecular weight regulator such as hydrogen can be used.

  The molar (feed) ratio ([A] / [B]) of ethylene [A] and α-olefin [B] is preferably 25/75 to 80/20, more preferably 30/70 to 70/30. is there.

  The molar (charge) ratio ([C-1] / [C-2]) of nonconjugated polyene [C-1] and nonconjugated polyene [C-2] is preferably 60/40 to 99.5 / 0. .5, more preferably 65/35 to 99/1.

  Polymerization using the above catalyst is preferable because a non-conjugated polyene having a double bond is copolymerized at a high conversion rate, and an appropriate amount of long chain branching can be introduced into the resulting copolymer (A). .

  In the copolymer (A) thus obtained, the structural unit derived from the α-olefin [B] having 3 to 20 carbon atoms is contained in 100 mol% of all structural units, preferably 10 to 50 mol%. Yes, more preferably 25 to 45 mol%. Further, the total of the molar ratio of the structural units derived from the non-conjugated polyene [C-1] and the molar ratio of the structural units derived from the non-conjugated polyene [C-2] is preferably 1 in 100 mol% of all the structural units. It is 0.0-6.0 mol%, More preferably, it is 1.0-5.0 mol%. Further, the ratio ([C-1] / [C-2] of mol% of structural units derived from non-conjugated polyene [C-1] and mol% of structural units derived from non-conjugated polyene [C-2]. ) Is preferably 75/25 to 99.5 / 0.5, more preferably 78/22 to 97/3.

[Filler (C)]
The filler (C) used in the present invention is not particularly limited. For example, a reinforcing material or an inorganic filler known to be added for the purpose of improving mechanical properties such as tensile strength, tear strength, and abrasion resistance can be used.

  Examples of the filler (C) include reinforcing materials such as carbon black, carbon black surface-treated with a silane coupling agent, silica, activated calcium carbonate, fine talc, and fine silicate. Of these, carbon black is preferable. As commercial products of carbon black, for example, trade names of Asahi Carbon Co., Ltd. Asahi # 55G, Asahi # 50HG, Asahi # 80, Asahi # 70, Asahi # 60H, Asahi # 60, Asahi # 50, Asahi # 35, Asahi # 15, Asahi Thermal, Tokai Carbon Co., Ltd. product name SEAST V, SEAST SVH, SEAST 6, SEAST 3, SEAST 116, SEAST SO, SEAST S.

  Further, as the filler (C), for example, inorganic fillers such as light calcium carbonate, heavy calcium carbonate, talc and clay can be used. Of these, heavy calcium carbonate is preferred. As a commercial item of heavy calcium carbonate, for example, trade name Whiten SB manufactured by Shiroishi Calcium Co., Ltd. may be mentioned.

  The blending amount of the filler (C) is 30 to 160 parts by mass, preferably 45 to 145 parts by mass, and more preferably 60 to 130 parts by mass with respect to 100 parts by mass of the copolymer (A). When the blending amount of the filler (C) is within the above range, the composition is excellent in kneadability, and the crosslinked foam has mechanical properties such as strength and flexibility, low temperature flexibility (low temperature compression stress) and permanent compression. This is preferable because it is excellent in distortion.

<Ethylene / α-olefin / non-conjugated polyene copolymer composition (X)>
The ethylene / α-olefin / non-conjugated polyene copolymer composition (X) of the present invention comprises 100 parts by mass of the ethylene / α-olefin / non-conjugated polyene copolymer (A) described above and a filler (C ) A composition containing 30 to 160 parts by mass and having a total compounding part of 150 parts by mass or more.

  Since the copolymer composition (X) contains the filler (C), the viscosity at the time of non-crosslinking is low, so that the workability at the time of molding is good. Further, by using the copolymer composition (X), a crosslinked foam having a low specific gravity and sufficient rigidity can be molded satisfactorily. Therefore, the copolymer composition (X) is very useful in applications where low specific gravity and sufficient rigidity are required.

  The copolymer composition (X) is prepared by kneading the copolymer (A), the filler (C), and other optional components at a predetermined temperature using a conventionally known kneader such as a mixer, a kneader, or a roll. Can be prepared. Since the copolymer (A) is excellent in kneadability, the copolymer composition (X) can be prepared satisfactorily. In the present invention, the composition of the copolymer composition (X) is specified based on 100 parts by mass of the copolymer (A). That is, it is necessary to mix at least 30 to 160 parts by mass of the filler (C) with respect to 100 parts by mass of the copolymer composition (X). Further, the total number of blended parts of the copolymer composition (X), that is, the total mass of the copolymer composition (X) is at least 150 parts by mass or more with respect to 100 parts by mass of the copolymer composition (X). It is necessary. In other words, the total amount of the filler (C) and other optional components is 50 parts by mass or more with respect to 100 parts by mass of the copolymer composition (X).

  Examples of other optional components include various additives such as foaming agents, foaming aids, softeners, anti-aging agents (stabilizers), processing aids, activators, and hygroscopic agents. Further, a polymer rubber other than the copolymer (A) can be blended. However, it is preferable not to include a crystalline resin. This is because when the crystalline resin is blended, the rigidity at normal temperature is improved, but the rubber elasticity at low temperature is lowered.

  Furthermore, the copolymer composition (X) may contain, for example, a crosslinking agent or a foaming agent.

  As a crosslinking agent, what is generally known as a vulcanizing agent can be used. Examples of the vulcanizing agent include sulfur compounds, organic peroxides, phenol resins, and oxime compounds.

  As the sulfur compound, for example, sulfur, sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide and selenium dithiocarbamate are preferable, and sulfur and tetramethylthiuram disulfide are more preferable. The compounding quantity of a sulfur type compound is 0.3-10 mass parts normally with respect to 100 mass parts of copolymers (A), Preferably it is 0.5-5.0 mass parts, More preferably, it is 0.7-4. 0.0 part by mass. These ranges are preferred because there is no bloom on the surface of the resulting crosslinked foam and excellent crosslinking properties are exhibited.

  Examples of the organic peroxide include dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, , 5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, di-t-butylperoxide, di-t-butylperoxy-3,3,5-trimethylcyclohexane, t-dibutylhydroperoxide are preferred Dicumyl peroxide, di-t-butyl peroxide and di-t-butylperoxy-3,3,5-trimethylcyclohexane are more preferred. The compounding amount of the organic peroxide is usually 0.001 to 0.05 mol, preferably 0.002 to 0.02 mol, more preferably 0.005 to 0.00 mol per 100 g of the copolymer (A). 015 mol. These ranges are suitable because they exhibit excellent crosslinking properties without blooming to the surface of the resulting crosslinked foam.

  When a sulfur compound is used as the vulcanizing agent, it is preferable to use a vulcanization accelerator in combination. Examples of the vulcanization accelerator include N-cyclohexyl-2-benzothiazole sulfenamide, N-oxydiethylene-2-benzothiazole sulfenamide, N, N′-diisopropyl-2-benzothiazole sulfenamide, 2 -Mercaptobenzothiazole (for example, Sunseller M (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)), 2- (4-morpholinodithio) penzothiazole (for example, Noxeller MDB-P (trade name; Ouchi Shinsei Chemical Industry Co., Ltd.) )), 2- (2,4-dinitrophenyl) mercaptobenzothiazole, 2- (2,6-diethyl-4-morpholinothio) benzothiazole and dibenzothiazyl disulfide, and the like; diphenylguanidine, triphenyl Guanidines such as guanidine and diorthotril guanidine Aldehydes such as acetaldehyde / aniline condensate and butyraldehyde / aniline condensate; imidazolines such as 2-mercaptoimidazoline; thioureas such as diethylthiourea and dibutylthiourea; tetramethylthiuram monosulfide and tetramethylthiuram disulfide, etc. Zinc thiodicarbamate: zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate (eg Sunseller PZ, Sunseller BZ, Sunseller EZ and Sunseller M (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.)) and tellurium diethyldithiocarbamate Dithioate salts such as ethylenethiourea (for example, Sunseller BUR (trade name; manufactured by Sanshin Chemical Co., Ltd.), Sunseller 22-C (trade name; Sanshin Chemical) Thiourea type such as N, N′-diethylthiourea; xanthate type such as zinc dibutylxatogenate; and others, zinc white (for example, META-Z102 (trade name; manufactured by Inoue Lime Industry Co., Ltd., zinc oxide) )). The blending amount of the vulcanization accelerator is usually 0.1 to 20 parts by mass, preferably 0.2 to 15 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the copolymer (A). Part.

  Vulcanizing aids can also be used. Examples of the vulcanization aid include quinone dioxime such as p-quinone dioxime; acrylic such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate; diallyl phthalate and triallyl isocyanurate (for example, M-60 ( And other maleimides; divinylbenzene; magnesium oxide / zinc oxide (for example, META-Z102 (trade name; manufactured by Inoue Lime Industry Co., Ltd.), etc.). It can be selected as appropriate according to the conditions. A vulcanization auxiliary may be used individually by 1 type, and may be used in combination of 2 or more types. The compounding quantity of a vulcanization adjuvant is 1-20 mass parts normally with respect to 100 mass parts of copolymers (A).

  When the copolymer composition (X) is crosslinked, for example, a hydrosilyl crosslinking agent or a resin crosslinking agent can be used as a known crosslinking agent other than the above-described sulfur vulcanizing agent and organic peroxide.

  The hydrosilyl crosslinking agent is a compound having at least two hydrosilyl groups in one molecule, and reacts with the copolymer rubber to act as a crosslinking agent. The blending amount of the hydrosilyl crosslinking agent is preferably 1.7 to 15 parts by mass, more preferably 1.7 to 10 parts by mass, particularly preferably 2.0 to 100 parts by mass of the copolymer (A). 10 parts by mass. These ranges are suitable because the mechanical strength of the resulting rubber molded article is improved and the roll addition time of the composition tends to be shortened.

  As the hydrosilyl crosslinking agent, those conventionally produced and marketed can be used. For example, it may have any structure such as a linear, annular, branched structure, or a resinous material having a three-dimensional network structure. Such a hydrosilyl group-based crosslinking agent is usually represented by the following general composition formula:

Can be used.

In the above general composition formula, R ⁴ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, excluding an aliphatic unsaturated bond. Examples of the monovalent hydrocarbon group include alkyl groups including isomers such as n-, iso-, sec-, and tert- ranging from methyl and ethyl groups to nonyl and decyl groups, phenyl groups, and halogen-substituted ones. An alkyl group, such as a trifluoropropyl group, can be mentioned. Of these, a methyl group, an ethyl group, a propyl group, a phenyl group, and a trifluoropropyl group are preferable, and a methyl group is particularly preferable. In the above general composition formula, b is 1 ≦ b <3, preferably 0.6 <b <2.2, particularly preferably 1.5 ≦ b ≦ 2, and c is 1 <c ≦ 3, preferably 1. ≦ c <2 and b + c is 0 <b + c ≦ 3, preferably 1.5 <b + c ≦ 2.7.

The hydrosilyl crosslinking agent is an organohydrogenpolysiloxane having preferably 2 to 1000, particularly preferably 2 to 300, most preferably 4 to 200 silicon atoms in one molecule. Specific examples thereof include siloxane oligomers, molecular chain-end-capped organohydrogenpolysiloxanes, R ⁴ ₂ (H) SiO _1/2 units and SiO _4/2 units, optionally R ⁴ ₃ SiO _{1/2. Mention} may be made of silicone resins which may comprise units, R ⁴ ₂ SiO _2/2 units, R ⁴ (H) SiO _2/2 units, (H) SiO _3/2 or R ⁴ SiO _3/2 units.

  When a crosslinking reaction with the copolymer (A) is performed using a hydrosilyl crosslinking agent, an addition reaction catalyst is usually used together. The catalyst is not particularly limited as long as it promotes the addition reaction (alkene hydrosilylation reaction) between the alkenyl group of the copolymer (A) and the hydrosilyl group of the hydrosilyl crosslinking agent. System catalysts are preferred. The amount of the catalyst is preferably 0.05 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, and particularly preferably 0.05 to 2.5 parts by mass with respect to 100 parts by mass of the copolymer (A). Part by mass. If this is 0.05 parts by mass or more, the crosslinking rate is high, and if it is 5 parts by mass or less, it is advantageous in terms of cost. Further, when a platinum-based catalyst is used in a blending amount within the above range, a vulcanized rubber molded article having an appropriate crosslinking density and excellent strength and elongation characteristics can be formed.

  The specific platinum-based catalyst may be a known one that is usually used for addition-curing type curing, such as a finely powdered metal platinum catalyst described in US Pat. No. 2,970,150, US Pat. Platinic acid catalyst described in US Pat. No. 3,823,218, platinum and hydrocarbon complex compounds described in US Pat. No. 3,159,601 and US Pat. No. 159,662, US Complex compounds of chloroplatinic acid and olefins described in Japanese Patent No. 3,516,946, platinum described in US Pat. No. 3,775,452 and US Pat. No. 3,814,780 And a complex compound of vinyl siloxane.

  More specifically, for example, platinum alone (platinum black), chloroplatinic acid, platinum-olefin complex, platinum-alcohol complex, or a carrier such as alumina, silica, etc., carrying a platinum carrier. They may be used alone or in combination of two or more at any ratio.

  The resin cross-linking agent is a synthetic resin that causes a cross-linking reaction to rubber by heating or the like. For example, phenol resin, melamine / formaldehyde resin, triazine / formaldehyde condensate, hexamethoxymethyl / melamine resin can be used. Among these, a phenol resin is preferable. Specific examples of the phenol resin include various phenol resins synthesized by reacting phenols such as phenol, alkylphenol, cresol, xylenol, and resorcin with aldehydes such as formaldehyde, acetaldehyde, and furfural. A halogenated phenol resin in which at least one halogen atom is bonded to the aldehyde unit of the phenol resin can also be used. In particular, alkylphenol-formaldehyde resins obtained by the reaction of formaldehyde with alkylphenols with alkyl groups bonded to the ortho or para position of benzene are excellent in compatibility with rubber and have a high reactivity, thus increasing the time for initiation of the crosslinking reaction. This is preferable because it can be done relatively quickly. The alkyl group of the alkylphenol / formaldehyde resin is usually an alkyl group having 1 to 10 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, and a butyl group. Moreover, the halide of this alkylphenol formaldehyde resin is also used suitably. Furthermore, a modified alkylphenol resin obtained by addition condensation of sulfurized p-tert-butylphenol and aldehydes, or an alkylphenol sulfide resin can also be used as a resin crosslinking agent.

  Examples of the foaming agent include inorganic foaming agents such as sodium bicarbonate and sodium carbonate; nitroso compounds such as N, N′-dinitrosopentamethylenetetramine and N, N′-dinitrosotephthalamide; azodicarbonamide and azo Azo compounds such as bisisobutyronitrile; hydrazide compounds such as benzenesulfonyl hydrazide and 4,4′-oxybis (benzenesulfonyl hydrazide); organic foams such as azide compounds such as calcium azide and 4,4′-diphenyldisulfonyl azide Agents. Commercially available products include, for example, VINYHALL AC # 3C-K2 (trade name; manufactured by Eiwa Kasei Kogyo Co., Ltd.), VINYHALL AC # LQ (trade name: manufactured by Eiwa Kasei Kogyo Co., Ltd., azodicarbonamide (abbreviated as ADCA)), neoselbon N # 1000SW, Neoselbon N # 1000M (trade name; manufactured by Eiwa Kasei Kogyo Co., Ltd., 4,4′-oxybis (benzenesulfonylhydrazide (abbreviation: OBSH)), Cellular D (trade name; manufactured by Eiwa Kasei Kogyo Co., Ltd., N, N ′) -Dinitrosopentamethylenetetramine (abbreviation DPT)), etc. The blending amount of the foaming agent is usually 1 to 70 parts by mass, preferably 3 to 60 parts by mass with respect to 100 parts by mass of the copolymer (A). It is preferable in terms of the amount of foaming gas generated.

  Moreover, in addition to a foaming agent, you may add a foaming adjuvant as needed. The foaming aid exhibits actions such as lowering the decomposition temperature of the foaming agent, promoting decomposition, or uniforming the bubbles. Examples of the foaming aid include organic acids such as salicylic acid, phthalic acid, stearic acid, oxalic acid and citric acid or salts thereof; urea or derivatives thereof. Examples of commercially available products include cell paste K5 (trade name; manufactured by Eiwa Kasei Kogyo Co., Ltd., urea) and FE-507 (trade name: manufactured by Eiwa Kasei Kogyo Co., Ltd., baking soda). The blending amount of the foaming assistant is usually 0.1 to 5 parts by mass, preferably 0.5 to 4 parts by mass with respect to 100 parts by mass of the copolymer (A).

  It is preferable that the blending amount of the foaming agent, foaming aid, vulcanizing agent, and vulcanization accelerator is in the above-mentioned range because there is no bloom on the surface of the resulting crosslinked foam and excellent crosslinking properties are exhibited.

  Also, physical foaming with high-pressure gas is possible. That is, for example, when extruding at a temperature near the melting point of the resin, the foam is continuously extruded by pressing a volatile or inorganic gas-based foaming agent through a press-fitting hole provided in the middle of the extruder and extruding it from the die. Can be obtained. Specific examples of the physical foaming agent include volatile foaming agents such as Freon, butane, pentane, hexane, and cyclohexane, and inorganic gas foaming agents such as nitrogen, air, water, and carbon dioxide. In addition, a bubble nucleating agent such as calcium carbonate, talc, clay or magnesium oxide may be added during extrusion foaming. The blending ratio of the physical foaming agent is usually 5 to 60 parts by mass, preferably 10 to 50 parts by mass with respect to 100 parts by mass of the copolymer (A). When the blending ratio of the physical foaming agent is too small, the foaming property of the foam is lowered, and conversely when it is too much, the strength of the foam is lowered.

  Softeners can also be used. Examples of softeners include process oils (eg, Diana Process Oil PS-430 (trade name; manufactured by Idemitsu Kosan Co., Ltd.)), lubricating oils, paraffin oil, liquid paraffin, petroleum asphalt, petroleum jelly and other petroleum softeners such as coal tar and Coal tar softeners such as coal tar pitch; fatty oil softeners such as castor oil, linseed oil, rapeseed oil, soybean oil and coconut oil; waxes such as beeswax, carnauba wax and lanolin; ricinoleic acid, palmitic acid, Fatty acids such as stearic acid, barium stearate, calcium stearate and zinc laurate or salts thereof; naphthenic acid, pine oil and rosin or derivatives thereof; synthetic polymers such as terpene resins, petroleum resins, atactic polypropylene and coumarone indene resins Material: Dioctylph Rate, ester softeners such as dioctyl adipate and dioctyl sebacate; other, microcrystalline wax, liquid polybutadiene, modified liquid polybutadiene, liquid Thiokol, hydrocarbon-based synthetic lubricating oil, tall oil and sub (factice), and the like. Of these, petroleum softeners are preferable, and process oil is particularly preferable. A softening agent may be used individually by 1 type, and may be used in combination of 2 or more types. The blending amount of the softener can be appropriately selected depending on the use. The blending amount is the maximum with respect to 100 parts by mass of the copolymer (A), usually 200 parts by mass, preferably 150 parts by mass, and more preferably 130 parts by mass.

  In addition, the product life can be extended by using an anti-aging agent (stabilizer) as in the case of a normal rubber composition. Examples of the anti-aging agent include conventionally known anti-aging agents such as amine-based anti-aging agents, phenol-based anti-aging agents, and sulfur-based anti-aging agents. Specifically, aromatic secondary amine-based antioxidants such as phenylbutylamine and N, N′-di-2-naphthyl-p-phenylenediamine; dibutylhydroxytoluene and tetrakis [methylene (3,5-di-t Phenolic antioxidants such as -butyl-4-hydroxy) hydrocinnamate] methane; thioethers such as bis [2-methyl-4- (3-n-alkylthiopropionyloxy) -5-t-butylphenyl] sulfide Anti-aging agent; dithiocarbamate anti-aging agent such as nickel dibutyldithiocarbamate; zinc salt of 2-mercaptobenzoylimidazole and 2-mercaptobenzimidazole; sulfur type such as dilaurylthiodipropionate and distearylthiodipropionate Anti-aging agent, etc.These anti-aging agents may be used alone or in combination of two or more. The blending amount of the anti-aging agent is usually 0.3 to 10 parts by mass, preferably 0.5 to 7.0 parts by mass, and more preferably 0.7 to 5 parts per 100 parts by mass of the copolymer (A). 0.0 part by mass. When the blending amount of the antioxidant is in the above range, there is no bloom on the surface of the resulting rubber composition, and it is preferable because vulcanization inhibition is not caused.

  Processing aids can also be used. As processing aids, those generally blended into rubber as processing aids can be widely used. Specific examples include ricinoleic acid, palmitic acid, lauric acid, stearic acid, stearates, barium stearate, zinc stearate, and calcium stearate. Of these, stearic acid is preferred. The blending amount of the processing aid is usually 10 parts by mass or less, preferably 8.0 parts by mass or less, more preferably 5.0 parts by mass or less with respect to 100 parts by mass of the copolymer (A). A blending amount of the processing aid within the above range is preferable because there is no bloom on the surface of the resulting rubber composition and vulcanization is not inhibited.

  Activators can also be used. Examples of the activator include amines such as di-n-butylamine, dicyclohexylamine, monoethanolamine, Acting B (trade name; manufactured by Yoshitake Pharmaceutical Co., Ltd.) and Acting SL (trade name; produced by Yoshitake Pharmaceutical Co., Ltd.); diethylene glycol, polyethylene glycol (Eg PEG # 4000 (trade name; manufactured by Lion)), lecithin, triarylate melitrate and zinc compounds of aliphatic and aromatic carboxylic acids (eg, Struktol activator 73, Struktol IB 531 and Struktol FA 541 (trade name) Active agents such as Scill &Seilacher)); zinc peroxide preparations such as ZEONET ZP (trade name; manufactured by Nippon Zeon); octadecyltrimethylammonium bromide; synthetic hydrotalcite; special quaternary ammonium compounds (eg, Arcard 2HT) -F (trade name; manufactured by Lion Akzo)) That. Among these, polyethylene glycol (for example, PEG # 4000 (trade name; manufactured by Lion Corporation)) and Arcade 2HT-F are preferable. This activator may be used individually by 1 type, and may be used in combination of 2 or more types. The blending amount of the activator is usually 0.2 to 10 parts by mass, preferably 0.3 to 5 parts by mass, more preferably 0.5 to 4 parts by mass with respect to 100 parts by mass of the copolymer (A). is there.

  Examples of the hygroscopic agent include calcium oxide, silica gel, sodium sulfate, molecular sieve, zeolite, white carbon and the like. Of these, calcium oxide is preferred. The amount of the hygroscopic agent is usually 0.5 to 15 parts by weight, preferably 1.0 to 12 parts by weight, more preferably 1.0 to 10 parts by weight with respect to 100 parts by weight of the copolymer (A). is there.

  In addition, additives usually used for rubber can be arbitrarily blended within a range not impairing the object of the present invention.

[Crosslinked foam (Y)]
The crosslinked foam (Y) of the present invention is a foam obtained by crosslinking and foaming the ethylene / α-olefin / non-conjugated polyene copolymer composition (X) described above. This crosslinked foam (Y) is molded using the copolymer composition (X), has a low specific gravity and sufficient rigidity, and also has good workability during molding. Therefore, this crosslinked foamed body (Y) is very useful in applications that require low specific gravity and sufficient rigidity (for example, automotive door sponge applications).

  The specific gravity of the cross-linked foam (Y) is preferably 0.3 to 0.5, more preferably 0.3 to 0.45, and the low elongation stress (σ25) is preferably 0.15 to 0.35 MPa, more It is preferably 0.15 to 0.30 MPa. In particular, when the low elongation stress (σ25) is within this range, a further special effect can be obtained, for example, excellent door closing performance in automotive door sponge applications.

  Examples of the method for crosslinking the copolymer composition (X) include the following two methods.

  In the first method, a rubber composition containing the above vulcanizing agent is usually mixed with an extrusion molding machine, a calender roll, a press, an injection molding machine, a transfer molding machine, hot air, a glass bead fluidized bed, UHF (ultra-high frequency). Electromagnetic wave), steam, and LCM (hot molten salt tank), etc., are pre-formed into a desired shape by a heating method such as a heating tank, and the preform is introduced into the vulcanizing tank at the same time as the pre-molding or heated. Method (i).

  In the case of the method (i), the vulcanizing agent described above is used, and if necessary, a vulcanization accelerator and / or a vulcanization auxiliary is also used. The heating temperature is generally 140 to 300 ° C, preferably 150 to 270 ° C, more preferably 150 to 250 ° C, usually 0.5 to 30 minutes, preferably 0.5 to 20 minutes, Preferably it is heated for 0.5 to 15 minutes.

  When molding and vulcanizing the copolymer composition (X), a mold may or may not be used. When no mold is used, the rubber composition is usually molded and vulcanized continuously.

  The second method is a method (ii) in which the copolymer composition (X) is preformed by the above molding method and irradiated with an electron beam.

  In the case of method (ii), an electron beam of 0.1 to 10 MeV is applied to the preformed material so that the absorbed dose is, for example, 0.5 to 35 Mrad, preferably 0.5 to 20 Mrad, more preferably 1 to 10 Mrad. Irradiate.

  In order to perform cross-linking foam molding, usually, a foaming agent is added to the copolymer composition (X) to perform cross-linking and foaming. As an example of the cross-linked foam molding, the copolymer composition (X) is subjected to a die temperature of 80 ° C. using a 60 φmm extruder equipped with a tubular die (inner diameter; height 13 mm × width 11 mm, wall thickness 1.5 mm). , Extruded at a cylinder temperature of 60 ° C. and a screw temperature of 50 ° C., molded into a tube shape and simultaneously introduced into a vulcanizing tank, UHF vulcanization (200 ° C., output 2 kW × 1 min) and hot air vulcanization (250 ° C. × 4 For example, a method for obtaining a tubular sponge by crosslinking and foaming.

  As described above, the copolymer composition (X) and the crosslinked foamed molded product (Y) of the present invention relate to a foam having good molding workability, low specific gravity and sufficient rigidity. Therefore, it can be suitably used for various applications by taking advantage of its characteristics. The crosslinked foamed body (Y) of the present invention is particularly useful as a sealing material, and can be suitably used in applications such as a high-foaming sealing material, automotive sealing material, civil engineering / architectural sealing material, and various industrial sealing materials. . Particularly suitable for weatherstrip sponge material (foaming ratio is preferably 1.3 to 4.0 times), and for example, high foaming sponge material used for sponges, dam rubber, etc. (foaming ratio is preferably 3.0 times) More than 30 times less).

  Specific examples of such rubber moldings include sponges for weather strips such as door sponges, opening trim sponges, hood seal sponges, trunk seal sponges, etc .; high foam sponge materials such as heat insulation sponges and dam rubbers Etc.

[Weather strip sponge]
Since the weatherstrip sponge of the present invention has a low specific gravity and sufficient rigidity, it is lightweight and has excellent door closing properties. The specific gravity of the weatherstrip sponge of the present invention is preferably 0.3 to 0.5, more preferably 0.3 to 0.45, and the low tensile stress (σ25) is preferably 0.15 to 0.35 MPa, more It is preferably 0.15 to 0.30 MPa. The weatherstrip sponge of the present invention is preferably obtained by crosslinking and foaming the above copolymer composition (X).

  Hereinafter, the present invention will be described in more detail with reference to examples. In the following description, “part” means “part by mass”. Moreover, each physical property was evaluated by the following methods.

(1) Composition and physical properties of copolymer (A) (content ratio of structural unit derived from component [A] and structural unit derived from component [B])
The content ratio (molar ratio and weight ratio) of the structural unit derived from component [A] and the structural unit derived from component [B] ([A] / [B]) is the intensity of the ¹³ C-NMR spectrometer. Obtained by measurement.

(Contents of structural unit derived from component [C] and structural unit derived from component [D])
Content (mol% and weight%) of the structural unit derived from the component [C] and the structural unit derived from the component [D] was determined by intensity measurement using a ¹³ C-NMR spectrometer.

The following is a description of copolymer rubbers obtained from ethylene, propylene, ENB, and VNB with respect to the compositional analysis of the copolymer rubber by a ¹³ C-NMR spectrometer (molar amount of each structural unit contained in the copolymer rubber). An example will be described.

The structure (composition) analysis of ethylene, propylene and ENB copolymer by ¹³ C-NMR spectrum meter was carried out by CJ Carman, RA Harrington, and CE Wilkes, Macromolecules, 10, p 536-544 (1977), Masahiro Kakugo. , Yukio Naito, Kooji Mizunuma, and Tatsuya, Miyatake, Macromolecules, 15, p 1150-1152 (1982) and G. Van der Velden, Macromolecules, 16, p 85-89 (1983). The analysis was performed in Harris Lasarov, Tuula T. Pakkanen, Macromol. Rapid Commun., 20, p 356-360 (1999) and Harri Lasarov *, Tuula T. Pakkanen, Macromol. Rapid Commun., 22, p 434-438 (2001). ).

First, the integrated value of each peak derived from 1) ethylene, 2) propylene, 3) ENB, and 4) VNB was determined by a ¹³ C-NMR spectrometer.
1) Ethylene; [Integral value of peak derived from ethylene chain + [Integral value of peak derived from ethylene-propylene chain] / 2],
2) Propylene; [Integral value of peak derived from propylene chain + [Integral value of peak derived from ethylene-propylene chain] / 2],
3) ENB; integrated value of ENB-3 peak, and 4) VNB; integrated value of VNB-7 peak.

  Each mol% was calculated from the obtained integral value ratio. The conversion to wt% was carried out with the molecular weight of ethylene being 28.05, the molecular weight of propylene being 42.08, and the molecular weights of ENB and VNB being 120.2 respectively.

(Apparent iodine value derived from VNB)
The apparent iodine value derived from the VNB (molecular weight 120.2) used as the component [D] of the copolymer rubber was calculated as follows using a ¹ H-NMR spectrometer and a ¹³ C-NMR spectrometer. did.

First, the weight% of each structural unit contained in the copolymer rubber was determined from a ¹³ C-NMR spectrometer.

Next, ¹ ) the integrated value of the peak derived from ENB and 2) the integrated value of the peak derived from the vinyl group of VNB were determined from a ¹ H-NMR spectrometer. The integrated values of the peaks represented by (a), (b) and (c) in the following 1) and 2) are respectively (a) and (b) in the following formulas (X) and (Y). And the integral value of the proton peak represented by (c).
1) Integral value of peak derived from ENB: (a) = {(total of plural peaks in the vicinity of 4.7 to 5.3 ppm) −2 × (c)}
(However, since (a) peak and (b) peak are detected together in the above (plural peaks in the vicinity of 4.7 to 5.3 ppm), only the peak of (a) was calculated from the above formula. )
2) Integral value of peak derived from vinyl group of VNB: (c) = (total of peaks around 5.5 to 6.0 ppm)

  The apparent iodine value derived from VNB (molecular weight 120.2) was calculated from the following equation using the obtained integrated value. The molecular weight of iodine is 253.81.

(Apparent iodine value derived from VNB) = {integral value of peak derived from vinyl group of VNB (c)} / {integral value of peak derived from ENB (a)} × { ¹³ C-NMR spectrum meter Obtained ENB content (% by weight)} × 253.81 / 120.2
(Intrinsic viscosity [η])
The intrinsic viscosity [η] (dL / g) of the copolymer rubber was measured in 135 ° C. decalin.

(Mooney viscosity [ML (1 + 4) 100 ℃])
The Mooney viscosity [[ML (1 + 4) 100 ° C.] at 100 ° C. was measured using a Mooney viscometer (SMV202 type, manufactured by Shimadzu Corporation) under the condition of 100 ° C. in accordance with JIS K6300.

[Viscoelasticity (branch index)]
(Frequency dependence of viscosity [η ^* ])
η ^* (0.01) and η ^* (10) were measured using a rheometric viscoelasticity tester (model ARES). Specifically, a sample formed into a disk shape having a diameter of 25 mm × 2 mm from a 2 mm thick sheet pressed at 190 ° C. was used, and the measurement was performed under the following conditions. Note that RSI Orchestrator (Rheometric) was used as data processing software.
Geometry: parallel plate,
Measurement temperature: 190 ° C.
Frequency: 0.01 to 500 rad / sec,
Distortion rate: 1.0%.

Under such conditions, the frequency dependence of the viscosity [η ^* ] was measured, and the viscosity [η ^* ] at 0.01 and 10 rad / sec were respectively determined as η ^* (0.01) and η ^* (10). It was. The following formula was calculated using the obtained numerical values.
Log {η ^* (0.01)} / Log {η ^* (10)}
(2) Physical properties of composition (X) [vulcanization rate (t5, Δt)]
(Minimum viscosity [Vm] and scorch time [t5])
Using a Mooney viscometer (SMV202 type, manufactured by Shimadzu Corporation), the change in Mooney viscosity was measured at 125 ° C., the minimum viscosity [Vm] was determined from the start of measurement, and 5 from the minimum viscosity [Vm]. The time until the point was raised was determined, and this was defined as the scorch time [t5] (min).

(3) Physical properties of foam [specific gravity]
Specific gravity was measured according to the underwater substitution method (JIS K 6268).

[Water absorption]
A test piece of 20 mm × 20 mm was punched out from the flat foam rubber vulcanized with hot air, and the surface dirt was wiped off with alcohol. The test piece was depressurized to -625 mmHg at a position 50 mm below the water surface and held for 3 minutes. Then, after returning to atmospheric pressure and passing for 3 minutes, the weight of the water-absorbed test piece was measured, and the water absorption rate was calculated from the following formula.
(Water absorption) = {(W2-W1) / W1}
W1: Weight before immersion (g).
W2: Weight after immersion (g).

[Low elongation stress (σ25)]
In accordance with JIS K 6254), the stress at an elongation (E _B ) of 25% was measured, and this measured value was defined as a low elongation stress (σ25).

[Stress at break [TB] and elongation at break [EB]]
A test piece was prepared by punching the upper part of the tubular sponge in the length direction with a No. 3 type dumbbell described in JIS K-6251 (1993). Using this test piece, in accordance with the method defined in JIS K-6251, paragraph 3, a tensile test was performed under the conditions of a measurement temperature of 25 ° C. and a tensile speed of 500 mm / min, and the tensile stress at break [TB] (MPa). And elongation at break [EB] (%) was determined.

[Surface roughness]
The surface roughness of the tube-like sponge was expressed by quantifying the irregularities on the upper surface of the tube-like sponge using a stylus type surface roughness measuring instrument. Actually, the sponge is cut to a length of 50 mm, and the height of the concave portion from the lowest to the tenth is calculated from “the sum of the heights of the convex portions from the highest to the tenth (h1)”. The value obtained by subtracting the value (h1−h2) obtained by subtracting “total (h2)” from 10 was defined as the surface roughness (μm) of the tubular sponge.

[50% compressive stress]
A hot-air crosslinked tube-like sponge is cut to 30 mm in the length direction and compressed so that the height of the test piece becomes 1/2 of the height before the load is applied, and the compression load (23 ° C., −30 ° C. ) And the compressive stress per unit cross-sectional area was calculated. The cross-sectional area was determined by the thickness of the sponge × the length of the sponge.

[Compression set (CS)]
The tubular sponge was cut 30 mm in the length direction, and the obtained test piece was attached to a compression set measuring mold. The specimen was compressed so that the height of the specimen was half that before applying the load, and the mold was set in a gear oven at 70 ° C. and heat-treated for 22 hours or 197 hours. Next, the test piece was taken out from the mold, allowed to cool for 30 minutes, the height of the test piece was measured, and compression set (CS) (%) was calculated from the following formula.

Compression set (CS) (%) = {(t ₀ −t ₁ ) / (t ₀ −t ₂ )} × 100
t ₀ : Height of the test piece before the test.
t ₁ : Height after heat-treating the specimen and allowing it to cool for 30 minutes.
t ₂ : Height of the test piece attached to the measurement mold.

[Shape retention]
Inner diameter: Height 13mm x Width 11mm, Wall thickness: 1.5mm Thickness of rubber composition formed into a tube shape and horizontal length (width) and rubber without changing the length and width The ratio of the height of the sponge obtained by crosslinking and foaming the composition and the length in the horizontal direction (width) was measured to obtain the shape retention rate (%).
Shape retention (%) = (L / D) / (L ₀ / D ₀ ) × 100
(In the formula, L ₀ is the height of the rubber composition molded into a tube shape; D ₀ is the width of the rubber composition molded into a tube shape; L is the height of the tube-shaped sponge; D is the tube shape. (Represents the width of the sponge.)
[Example 1]
First, 100 parts of the copolymer (A) shown in Table 1 and the following components were kneaded using MIXTRON BB MIXER (Kobe Steel Works, BB-4 type, volume 2.95 L, rotor 4WH). .

100 parts of copolymer (A) [ethylene-propylene-ENB-VNB quaternary copolymer obtained using a metallocene catalyst (ethylene content 62 mole ratio, ENB content 20 g / 100 g, VNB content 0.8 g / 100 g, ML (1 + 4) 100 ° C. = 32, Log [η ^* (0.01)] / Log [η ^* (10)] = 1.41, 0.0753 × D + 1.32 = 1.38 (D is non-conjugated polyene [C -2] Apparent iodine number derived from]
Filler (C): Carbon black (Asahi Carbon Co., Ltd., trade name Asahi # 50G) 64 parts Filler (C): Heavy calcium carbonate (Shiraishi Calcium Co., Ltd., trade name Whiten SB) 30 parts Process oil (Idemitsu Kosan Co., Ltd., trade name Diana Process Oil PS-430) 11 parts Hygroscopic material (Inoue Lime Industry, trade name Vesta 18) 5 parts Vulcanizing aid (Inoue Lime Industry, trade name Meta Z102) 5 parts 1 part of stearic acid 1 part of polyethylene glycol (manufactured by Lion, trade name PEG # 4000) The above kneading conditions were: rotor rotation speed 50 rpm, floating weight pressure 3 kg / cm ² , kneading time 5 minutes, kneading discharge temperature 150 ° C. .

  Subsequently, after confirming that this compounded temperature became 40 degrees C or less, each following component was further knead | mixed using the 14-inch roll.

Vulcanization accelerator (manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sunseller DM) 1.5 parts Vulcanization accelerator (manufactured by Sanshin Chemical Industry Co., Ltd., trade name Sunceller BZ) 1 part Vulcanization accelerators (Sanshin Chemical Industry Co., Ltd.) Product name 22) 1 part Vulcanization accelerator (manufactured by Sanshin Chemical Industry Co., Ltd., trade name TE) 0.2 part Sulfur (S) 1.5 parts Foaming agent (Yewa Kasei Kogyo Co., Ltd., trade name N1000SW) 4 Part The kneading conditions are as follows: roll temperature is front roll / rear roll = 55 ° C./60° C., roll peripheral speed is front roll / rear roll = 13.5 rpm / 12 rpm, roll gap is 4 mm, and kneading time is 8 minutes. I put it out.

  The polymer composition (X) obtained as described above was converted into a tube-like sponge (inner diameter: height 13 mm × width 11 mm, wall thickness) using an extruder (cylinder diameter 60 mmφ, compression ratio 1.5). 1.5mm) after extrusion (extrusion speed 3m / min), UHF vulcanization (200 ° C, output 2kW x 1min) and hot air vulcanization (250 ° C x 4min), and cut the extrudate to 150mm length Thus, each test piece (crosslinked foam) was prepared. Each physical property value is shown in Table 1.

[Example 2]
Example 1 except that 4 parts of vulcanization accelerator (trade name N1000M, manufactured by Sanshin Chemical Industry Co., Ltd.) was used instead of 4 parts of vulcanization accelerator (trade name: N1000SW, manufactured by Sanshin Chemical Industry Co., Ltd.) Similarly, a polymer composition was prepared to obtain a crosslinked foam. Each physical property value is shown in Table 1.

[Comparative Examples 1-5]
Except having changed the copolymer (A) as shown in Table 1, the polymer composition was prepared like Example 1 and the crosslinked foam was obtained. Each physical property value is shown in Table 1.

Claims (10)

Contains 100 parts by mass of ethylene / α-olefin / non-conjugated polyene copolymer (A) satisfying the following requirements (1) to (3) and 30 to 160 parts by mass of filler (C), and the total number of blended parts Is an ethylene / α-olefin / non-conjugated polyene copolymer composition (X) of 150 parts by mass or more.
(1) The ethylene / α-olefin / non-conjugated polyene copolymer (A) is ethylene [A], an α-olefin [B] having 3 to 20 carbon atoms, the following general formula (I) or (II): A non-conjugated polyene [C-1] containing only one partial structure represented in the molecule,

(However, (I) is a partial structure of cyclic olefin.)

And a structural unit derived from non-conjugated polyene [C-2] containing two or more partial structures selected from the group consisting of general formulas (I) and (II) in the molecule.
(2) The Mooney viscosity [ML (1 + 4) 100 ° C.] at 100 ° C. of the ethylene / α-olefin / non-conjugated polyene copolymer (A) is 20-45.
(3) The ethylene / α-olefin / non-conjugated polyene copolymer (A) satisfies the following formula (i).
Log {η ^* (0.01)} / Log {η ^* (10)}> 0.0753 × {apparent iodine value derived from non-conjugated polyene [C-2]} + 1.32 (i)
(Where η ^* (0.01) represents a viscosity (Pa · sec) of 0.01 rad / sec at 190 ° C., and η ^* (10) represents a viscosity (Pa · sec of 10 rad / sec at 190 ° C. )   The ethylene / α-olefin / non-conjugated polyene copolymer composition (X) according to claim 1, comprising at least 30 parts by mass of carbon black as at least one filler (C).   The non-conjugated polyene [C-1] is 5-ethylidene-2-norbornene (ENB), and the non-conjugated polyene [C-2] is 5-vinyl-2-norbornene (VNB). Ethylene / α-olefin / non-conjugated polyene copolymer composition (X).   A crosslinked foam (Y) obtained by crosslinking and foaming the ethylene / α-olefin / non-conjugated polyene copolymer composition (X) according to claim 1.   The cross-linked foam (Y) according to claim 4, wherein the specific gravity is 0.3 to 0.5, and the low tensile stress (σ25) is 0.15 to 0.35 MPa.   A method for producing a crosslinked foam, wherein the ethylene / α-olefin / non-conjugated polyene copolymer composition (X) according to claim 1 is crosslinked and foamed.   A weatherstrip sponge obtained from the ethylene / α-olefin / non-conjugated polyene copolymer composition (X) according to claim 1.   The weatherstrip sponge according to claim 7, wherein the specific gravity is 0.3 to 0.5, and the low tensile stress (σ25) is 0.15 to 0.35 MPa.   A method for producing a weatherstrip sponge, wherein the ethylene / α-olefin / non-conjugated polyene copolymer composition (X) according to any one of claims 1 to 3 is crosslinked and foamed.   The specific gravity is 0.3 to 0.5, and the low tensile stress (σ25) is 0.15 to 0.5, using a composition containing an ethylene / α-olefin / nonconjugated polyene copolymer and a filler. A weatherstrip sponge of 35 MPa.