JPH08151488A - Ethylene/alpha-olefin/nonconjugated diene copolymer rubber composition - Google Patents

Abstract

PURPOSE: To obtain an ethylene/α-olefin/nonconjugated diene copolymer rubber composition which is foamable at a high expansion ratio, undergoes no reduction in rigidity, has a low compression set when highly expanded, and is excellent in shape retentivity, etc., when crosslinked and expanded by using two specified ethylene/α-olefin/nonconjugated diene copolymers as the constituents. CONSTITUTION: This composition contains an ethylene/α-olefin/nonconjugated diene copolymer (A) wherein the weight ratio of ethylene to α-olefin is (40:60) to (70:30) and which contains a nonconjugated diene in an amount sufficient to provide an iodine value of 35 to 50 and has a branch index g' of 0.5 to 0.9 and a Mooney viscosity (ML1+8 120 deg.C) of 20 to 65 and an ethylene/α-olefin/ nonconjugated diene copolymer (B) wherein the weight ratio of ethylene to α-olefin is (70:30) to (90:10), which contains a nonconjugated diene in an amount sufficient to provide an iodine value of 3 to 20 and has a Mooney viscosity (ML1+8 120 deg.C) of 65 to 300 and of which the crystalline part comprising ethylene chains has a melting point of 40 deg.C or above as measured by DSC. The weight ratio of component A to component B is (30:70) to (70:30).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention contains two specific ethylene-α-olefin-non-conjugated diene copolymers, has high foaming property, good processability, and high foaming property. However, it has high rigidity and is excellent in compression set, kneading processability, extrusion processability, shape retention during vulcanization and foaming, etc., and is useful for a wide range of applications including sealing materials for automobiles. The present invention relates to a non-conjugated diene copolymer rubber composition.

[0002]

2. Description of the Related Art Ethylene-α-olefin-non-conjugated diene copolymer rubber is excellent in various properties such as heat resistance, ozone resistance and weather resistance, and sponge rubber, especially automobile door seals, roof side rails and trunks. It is widely used as a sealing material such as a seal, but as the performance of automobiles has increased in recent years, a high level is required for the performance required for these sponge rubbers. For example, problems such as engine noise generated when a car runs at high speed, noise such as wind noise around the door leaking into the room, and rain leakage are related to the sealing performance of the sponge rubber around the door (this is proportional to the rigidity of the sponge rubber). The sponge rubber used is required to have extremely high sealing performance. Further, when the door of an automobile is closed, the sponge rubber is put in a compressed state for a long time, so that the "settling" (which is generally represented by the compression set) as a result of compression is small. Is considered important. Therefore, the sealing performance of sponge rubber and low "fatigue"
The demands for realization are becoming more stringent. Further, in recent years, since the cross-sectional shape of sponge rubber for automobile sealing materials has become complicated, when sponge rubber is manufactured by a normal continuous vulcanization method, it is deformed by its own weight before the completion of vulcanization and foaming. Since there is also a problem that collapse occurs and the desired shape cannot be maintained, there is a strong demand for a sponge rubber excellent in shape retention, which is an index of shape collapse. Moreover, in order to meet the demand for cost reduction of sponge rubber, the sponge rubber is highly foamed, that is, the foaming specific gravity is reduced, while the high sealing performance, low “settling” property,
There is a new demand for sponge rubbers that are generally superior in shape retention. Further, in addition to the properties described above, it is also necessary that the sponge rubber has excellent kneading processability, roll processability, extrusion processability, etc., in addition to the performance as a sponge rubber. In particular, during kneading and extrusion processing, so-called "bugs" and "gels" are less likely to be generated, and the extruded surface is good, which is strictly required in order to improve the appearance of sponge rubber and enhance its commercial value. ing. Under such circumstances, for example, JP-A-3-20339 discloses that the ethylene / α-olefin-nonconjugated diene copolymer rubber has an ethylene / α-olefin weight ratio of 73/27 to 40/6.
0, Mooney viscosity (ML _{1 + 4} 121 ℃) 135-20
A method has been proposed in which the content of the diolefin is 0, the iodine value is 10 to 36, and the molecular weight is increased to improve the compression set. However, in such a method, since the molecular weight is high, the viscosity of the compound becomes high and it is difficult to highly foam the compound with a usual blending amount of carbon black and oil. Moreover, if high foaming is to be performed, a large amount of oil needs to be added, which has the drawback of lowering the shape retention and rigidity. In addition, JP-A-4-80245
The publication discloses that the copolymer comprises a low molecular weight copolymer and a high molecular weight copolymer, and has an ethylene / α-olefin weight ratio of 73/27.
~ 40/60, diolefin content is 10 in iodine value
36, the low molecular weight copolymer and the high molecular weight copolymer have an iodine value ratio of 1.1 / 1 to 4/1 and a Mooney viscosity (ML _{1 + 4} 121 ° C.). A rubber composition for sponge of 50 to 100 has been proposed. However, although this composition has a small compression set and good extrusion processability and shape retention, it has the drawback that the sponge rubber has a low rigidity when highly foamed. Further fairness 2
No. 62582 discloses ethylene, α-olefin,
5-ethylidene-2-norbornene (ENB) and 5
-Vinyl-2-norbornene (VNB) copolymer, ENB / VNB copolymer molar ratio of 1/1 to 20 /
1, the total content of ENB and VNB is 2 to 4 in iodine value
A copolymer rubber having an amount of 0 and having a specific molecular weight and molecular weight distribution is disclosed. However, this rubber has good roll processability and extrusion processability, and in particular, a sponge rubber having a smooth surface skin of the extrudate can be obtained, but the compression set of the sponge rubber when highly foamed is large, and the rigidity is high. Is also low.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to have a high foaming property, and when it is highly foamed, the rigidity is not particularly lowered, the compression set is small, and the shape retention property at the time of crosslinking / foaming is improved. An object of the present invention is to provide an ethylene-α-olefin-non-conjugated diene copolymer rubber composition which can provide a sponge rubber having a good balance of physical properties and which is excellent in kneading processability, extrusion processability and the like.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a relatively low molecular weight copolymer having a high iodine value and a high branching index, and a crystal with a low iodine value. Ethylene-α-olefin-non-conjugated diene copolymer rubber composition containing a relatively high molecular weight copolymer having a flexible portion has a high foaming property, and when it is highly foamed, the rigidity is particularly lowered. , Excellent in compression set and shape retention during vulcanization / foaming, less edge breakage during extrusion, smooth surface skin of extruded products, and generation of "bugs" and "gels" during kneading and extrusion Found that there are few,
The present invention has been completed. The present invention (A) has a weight ratio of ethylene / α-olefin of 40/60 to 70/30, contains an amount of non-conjugated diene to give an iodine value of 35 to 50, and has a branching index g ′ of 0. 5 to 0.9, and
Two-viscosity (ML _{1 + 8} 120 ° C.) 20-65 ethylene-α-olefin-non-conjugated diene copolymer, and (B) ethylene / α-olefin weight ratio 70 / 30-
90/10, containing an amount of non-conjugated diene of 3 to 20 in iodine value, and having a Muni-viscosity (ML _{1 + 8} 120
Ethylene) having a melting point of 40 ° C. or higher in the crystalline part composed of ethylene chains measured by DSC.
It contains an α-olefin-non-conjugated diene copolymer and has a weight ratio of component (A) to component (B) of 30/70 to 70/3.
Ethylene-α-olefin- characterized by being 0
The gist is a non-conjugated diene copolymer rubber composition.

The present invention will be described in detail below. The ethylene-α-olefin-non-conjugated diene copolymer rubber composition of the present invention (hereinafter referred to as “copolymer rubber composition”) is the specific (A) ethylene-α-olefin-non-conjugated diene copolymer. (Hereinafter, referred to as “copolymer rubber (A)”) and the specific (B) ethylene-α-olefin-non-conjugated diene copolymer (hereinafter, referred to as “copolymer rubber (B)”). It is characterized by doing. The copolymer rubber (A) is a copolymer rubber having a relatively low molecular weight, and basically lowers the molecular weight of the entire copolymer rubber composition to enhance high foamability, kneading processability, roll processability and It is a component that contributes to the improvement of extrusion processability. Further, the copolymer rubber (A) has a low ethylene content and a relatively high content of non-conjugated diene as compared with the conventional copolymer rubber composition in order to minimize a decrease in compression set and the like at a low temperature. In order to increase the vulcanization rate and to minimize the deterioration of the shape-retaining property due to the lower molecular weight, it has a small branching index g '. As described above, the high iodine value in the copolymer rubber (A) increases the vulcanization rate of the entire copolymer rubber composition because the copolymer rubber (B) described later is crystalline and has a low iodine value. It is a requirement that is necessary to improve the compression set of sponge rubber by increasing the content of non-conjugated diene because the low molecular weight rubber component has a large compression set. . Next, the copolymer rubber (B) is a copolymer rubber having a relatively high molecular weight, and basically contains a relatively large amount of ethylene to form a crystalline portion composed of an ethylene chain, It is a component that has a low content of conjugated dienes and contributes to the improvement of rigidity and shape retention of sponge rubber. As described above, according to the present invention, it is possible to achieve the purpose, particularly suitable for sponge rubber, only by blending the copolymer rubber (A) and the copolymer rubber (B) having different characteristics at a specific ratio. That is, a copolymer rubber composition that can be obtained is obtained. In addition, the copolymer rubber composition of the present invention is also characterized in that the rubber compound obtained therefrom becomes relatively hard due to the crystallinity of the copolymer rubber (B), and the compound can be easily pelletized. Have.

Copolymer rubber (A) and copolymer rubber (B)
Examples of the α-olefin used in C.
.About.12 .alpha.-olefins, specifically propylene, butene-1,3-methylbutene-1, pentene-1,3-methylpentene-1,4-methylpentene-1,3-ethylpentene. -1, hexene-1, octene-1, decene-1, dodecene-1 and the like can be mentioned, and propylene is particularly preferable. These α-olefins may be used alone or in combination of two or more. The non-conjugated diene used in the copolymer rubber (A) and the copolymer rubber (B) is, for example, 5-
In addition to ethylidene-2-norbornene (hereinafter referred to as “ENB”) and dicyclopentadiene (hereinafter referred to as “DCP”), α, ω-dienes having 8 to 20 carbon atoms in the main chain (hereinafter referred to as “α, ω”). -Diene ") and the like. The α, ω-diene is represented by the following formula (1).

[0007]

Embedded image

[In the formula (1), each R may be the same as or different from each other, and is a hydrogen atom, a saturated aliphatic hydrocarbon group having 1 to 10 carbon atoms, an unsaturated aliphatic hydrocarbon having 1 to 10 carbon atoms. Group, a saturated alicyclic hydrocarbon group having 1 to 10 carbon atoms or an unsaturated alicyclic hydrocarbon group having 1 to 10 carbon atoms, and n is 4
Is an integer from 16 to 16. ] Specific examples of such α, ω-dienes include 1,7-
Octadiene, 1,8-nonadiene, 1,9-decadiene, 1,11-dodecadiene, 1,13-tetradecadiene, 1,15-hexadecadiene, 1,17-octadecadiene, 1,19-icosadiene, 3,6-dimethyl-1,7-octadiene, 4,5-dimethyl-1,7
-Octadiene, 5-methyl-1,8-nonadiene and the like can be mentioned, and from the viewpoint of cost, 1,7-octadiene and 1,9-decadiene are particularly preferable. Α, ω-
The dienes may be used alone or in admixture of two or more.

[0009] Ethylene / alpha-olefin weight ratio in the copolymer rubber (A) the copolymer rubber (A) is 40 / 60-70 / 30, preferably 45/5
5 to 65/35. In this case, when the ethylene / α-olefin weight ratio is less than 40/60, the dispersion of the filler in the copolymer rubber composition becomes insufficient, the surface texture deteriorates, and the strength of the sponge rubber decreases, while 70 / Thirty
When it exceeds, the compression set of the sponge rubber at low temperature increases. The content of the non-conjugated diene in the copolymer rubber (A) is an amount that provides an iodine value of 35 to 50, preferably 42 to 50. In this case, the iodine value is 35
If it is less than 1, the compression set of the sponge rubber becomes large, and the crosslinking speed becomes slow, resulting in deterioration of the surface skin due to outgassing and deterioration of shape retention. On the other hand, if the iodine value is more than 50, the kneading process becomes difficult. In addition, "bugs" and "gels" are likely to occur during extrusion processing, and the balance between the crosslinking rate and the foaming rate is impaired, making it difficult to highly foam the copolymer rubber composition. From the viewpoint of increasing the vulcanization rate, ENB is preferable as the non-conjugated diene of the copolymer rubber (A), and DCP or α, ω-diene is preferably used in combination as a component contributing to branch formation, and particularly, From the viewpoint of easy availability, it is preferable to use DCP in combination with ENB. The content of each non-conjugated diene in the preferred copolymer rubber (A) is as follows. Copolymer rubber (A)
The ENB content of is an amount that provides an iodine value of 35 to 50, preferably 38 to 48. In this case, ENB
When the elemental value is less than 35, the compression set of the sponge rubber becomes large, and the crosslinking speed becomes slow, so that the surface texture is deteriorated due to gas escape and the shape retention is deteriorated. During the kneading process and the extrusion process, "bugs" and "gels" are likely to occur, the balance between the crosslinking rate and the foaming rate is impaired, and it becomes difficult to highly foam the copolymer rubber composition. In addition, DC of copolymer rubber (A)
The P content is an amount that provides an iodine value of 3 to 20, preferably 4 to 15. In this case, if the iodine value by DCP is less than 3, the shape retention of the sponge rubber tends to decrease, while if it exceeds 20, extrusion processability tends to decrease. When ENB and α, ω-diene are used together as the non-conjugated diene in the copolymer rubber (A), the α, ω-diene content is 0.0
It is 5 to 5% by weight, preferably 0.05 to 2% by weight.
In this case, if the α, ω-diene content is less than 0.05% by weight, the shape retention of the sponge rubber tends to decrease, while if it exceeds 5% by weight, the extrudability tends to decrease. However, when the copolymer rubber (A) contains ENB and DCP or an α, ω-diene as the non-conjugated diene, the total content of the non-conjugated diene is 35 to 5 in iodine value.
0. The branching index g'of the copolymer rubber (A) is 0.5.
˜0.9, preferably 0.5 to 0.8, more preferably 0.5 to 0.7. In this case, if the branching index g'is less than 0.5, roll processability, extrusion processability, etc. are deteriorated, while if it exceeds 0.9, the shape retention of the sponge rubber is deteriorated and the surface skin is deteriorated due to gas escape. Etc. Here, the branching index g ′ is defined by the following equation. g ′ = [η] obs / [η] liner where [η] obs is the measured intrinsic viscosity of the copolymer rubber (A), and [η] liner is a linear ethylene-propylene copolymer (EPM) in advance. ) Is the intrinsic viscosity obtained by substituting the measured molecular weight of the copolymer rubber (A). Furthermore, the Mooney viscosity (M) of the copolymer rubber (A)
L _{1 + 8} 120 ° C.) (hereinafter, simply referred to as “Moonie viscosity”) is 20 to 65, preferably 25 to 60. In this case, when the Mooney viscosity is less than 20, the shape retention of the sponge rubber is deteriorated and the surface texture is deteriorated due to gas escape during vulcanization and foaming. It becomes difficult, and kneading processability, extrusion processability, etc. are also deteriorated. The weight average molecular weight of the copolymer rubber (A) (M
The molecular weight distribution (Mw / Mn) represented by the ratio of w) to the number average molecular weight (Mn) is preferably 3 to 10.

Copolymer rubber (B) The copolymer rubber (B) has an ethylene / α-olefin weight ratio of 70/30 to 90/10, preferably 73/2.
7 to 85/15. In this case, when the ethylene / α-olefin weight ratio is less than 70/30, the crystalline portion composed of ethylene chains is reduced, and the rigidity of the sponge rubber is reduced, while when it exceeds 90/10, the copolymer rubber (B) is obtained.
The viscosity becomes high at the time of manufacturing, and the reactor is easily soiled. The content of the non-conjugated diene in the copolymer rubber (B) is such that the iodine value is 3 to 20, preferably 5 to 10.
Is the amount. In this case, when the iodine value due to the non-conjugated diene is less than 3, the compression set of the sponge rubber becomes large and the crosslinking rate becomes slower, so that the surface texture is deteriorated due to outgassing. The formation of a crystalline part composed of an ethylene chain in the copolymer rubber (B) is hindered, the rigidity of the sponge rubber is lowered, and "butsu" and "gel" are likely to occur during kneading and extrusion. The non-conjugated diene of the copolymer rubber (B) is E
NB is preferred, and DCP or α, ω-dienes can be used in combination with ENB if desired. The content of each non-conjugated diene in the preferable copolymer rubber (B) is as follows. The ENB content of the copolymer rubber (B) is such that the iodine value is 3 to 20, preferably 5 to 20, and particularly preferably 5 to 10. In this case, when the iodine value according to ENB is less than 3, the compression set of the sponge rubber becomes large and the crosslinking rate becomes slower, resulting in deterioration of the surface skin due to outgassing. The production of a crystalline part consisting of an ethylene chain in the rubber (B) is hindered, the rigidity of the sponge rubber is lowered, and "butsu" and "gel" are likely to occur during kneading and extrusion. Copolymer rubber (B) D
The CP content is an amount such that the iodine value is 0 to 10, preferably 0 to 6. In this case, when the elemental value by DCP exceeds 10, the extrusion processability tends to decrease. The α, ω-diene content of the copolymer rubber (B) is 0 to 2% by weight, preferably 0 to 1% by weight, based on the total monomer components. In this case, if the α, ω-diene content exceeds 2% by weight, the extrusion processability tends to decrease. However, when the copolymer rubber (B) contains ENB and DCP or an α, ω-diene as the non-conjugated diene, the total content of the non-conjugated diene is 3 to 20 in iodine value. The Mooney viscosity of the copolymer rubber (B) is 65 to 300, preferably 80 to 300. In this case, the Mooney viscosity is 65.
When it is less than 1, the shape retention of the sponge rubber is reduced and the compression set is increased, and the surface texture is deteriorated due to gas escape during vulcanization and foaming, and the ethylene chain length is shortened as the molecular weight is decreased. On the other hand, if the crystallinity exceeds 300, high foaming becomes difficult, and kneading processability, extrusion processability and the like also deteriorate. Further, the melting point (hereinafter, referred to as "ethylene crystal melting point") of the crystalline portion of the ethylene chain of the copolymer rubber (B) measured by DSC is 40 ° C or higher, preferably 40 to 120 ° C. In this case, if the ethylene crystal melting point is lower than 40 ° C., the rigidity of the sponge rubber is lowered. The molecular weight distribution (Mw / Mn) represented by the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the copolymer rubber (B) is preferably 2-4.

Copolymer rubber (A) and copolymer rubber (B)
The copolymer rubber (A) and the copolymer rubber (B) used in the present invention can be manufactured by an ordinary manufacturing method. Examples of the polymerization method include ethylene, α-olefin and non-conjugated diene in a suitable solvent in the presence of a Ziegler catalyst such as a catalyst consisting of a hydrocarbon solvent-soluble vanadium compound and an organoaluminum compound. Then, a method of polymerizing while supplying hydrogen as a molecular weight regulator if necessary, an organic transition metal compound such as a transition metal compound having a ligand composed of a group having a conjugated π electron in a suitable solvent, and an aluminoxane compound or in the presence of a catalyst comprising a silicon compound should have a fluorinated made from an aromatic group optionally substituted group, ethylene, supply hydrogen to α-olefin and a non-conjugated diene, as a molecular weight modifier if necessary And a method of polymerizing the same. In the above method, the hydrocarbon solvent-soluble vanadium compound is preferably VOCl ₃ , VCl ₄ , or a reaction product of VOCl ₃ and / or VCl ₄ and an alcohol. Examples of the alcohol include methanol, ethanol, n
-Propanol, i-propanol, n-butanol,
sec-butanol, t-butanol, n-hexanol, n-octanol, 2-ethylhexanol, n-
Examples thereof include decanol and n-dodecanol, but alcohols having 3 to 8 carbon atoms are preferable. Examples of the organic aluminum compound include triethylaluminum, tri-i-butylaluminum,
Examples thereof include tri-n-hexyl aluminum, diethyl aluminum monochloride, di-i-butyl aluminum monochloride, ethyl aluminum sesquichloride, butyl aluminum sesquichloride, ethyl aluminum dichloride and butyl aluminum dichloride. These organoaluminum compounds may be used alone or in combination of two or more, and particularly preferred organoaluminum compounds are ethylaluminum sesquichloride, butylaluminum sesquichloride,
It is a mixture of ethylaluminum sesquichloride and tri-i-butylaluminum, and a mixture of butylaluminum sesquichloride and tri-i-butylaluminum.

Next, in the above method, examples of the organic transition metal compound include bis (cyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) zirconium dibromide, and bis (cyclopentadienyl) zirconium dimethyl. Bis (cyclopentadienyl) zirconium diphenyl, dimethylsilylbis (cyclopentadienyl) zirconium dichloride,
Dimethylsilylbis (cyclopentadienyl) zirconium dimethyl, methylenebis (cyclopentadienyl)
Zirconium dichloride, ethylenebis (cyclopentadienyl) zirconium dichloride, bis (indenyl) zirconium dichloride, bis (indenyl) zirconium dimethyl, dimethylsilylbis (indenyl)
Zirconium dichloride, methylenebis (indenyl)
Zirconium dichloride, bis (4,5,6,7-tetrahydroindenyl) zirconium dichloride, bis (4,5,6,7-tetrahydroindenyl) zirconium dimethyl, dimethylsilylbis (4,5,6,7-
Tetrahydro-1-indenyl) zirconium dichloride, dimethylsilylbis (4,5,6,7-tetrahydro-1-indenyl) zirconium dimethyl, ethylenebis (4,5,6,7-tetrahydro-1-indenyl) zirconium dichloride, Bis (methylcyclopentadienyl) zirconium dichloride, bis (methylcyclopentadienyl) zirconium dimethyl, dimethylsilylbis (3-methyl-1-cyclopentadienyl)
Zirconium dichloride, methylenebis (3-methyl-
1-cyclopentadienyl) zirconium dichloride,
Bis (t-butylcyclopentadienyl) zirconium dichloride, dimethylsilylbis (3-t-butyl-1)
-Cyclopentadienyl) zirconium dichloride, bis (1,3-dimethylcyclopentadienyl) zirconium dichloride, dimethylsilylbis (2,4-dimethyl-1-cyclopentadienyl) zirconium dichloride, bis (1,2,2 4-trimethylcyclopentadienyl) zirconium dichloride, dimethylsilylbis (2,3,5-trimethyl-1-cyclopentadienyl) zirconium dichloride, bis (fluorenyl) zirconium dichloride, dimethylsilylbis (fluorenyl) zirconium dichloride, ( Fluorenyl) (cyclopentadienyl) zirconium dichloride, dimethylsilyl (fluorenyl) (cyclopentadienyl) zirconium dichloride, (t-butylamide) (1,
2,3,4,5-pentamethylcyclopentadienyl)
Zirconium dichloride, dimethylsilyl (t-butylamide) (2,3,4,5-tetramethyl-1-cyclopentadienyl) zirconium dichloride, methylene (t-butylamide) (2,3,4,5-tetramethyl- 1-cyclopentadienyl) zirconium dichloride, (phenoxy) (1,2,3,4,5-pentamethylcyclopentadienyl) zirconium dichloride, dimethylsilyl (o-phenoxy) (2,3,4,5-tetra Methyl-1-cyclopentadienyl) zirconium dichloride, methylene (o-phenoxy) (2,3,3
4,5-Tetramethyl-1-cyclopentadienyl) zirconium dichloride, ethylene (o-phenoxy)
Examples thereof include (2,3,4,5-tetramethyl-1-cyclopentadienyl) zirconium dichloride, and compounds in which zirconium in these compounds is replaced with titanium or hafnium, but are not limited thereto. is not. These organic transition metal compounds may be used alone or in combination of two or more.

Examples of the aluminoxane compound include a linear aluminoxane compound represented by the following general formula [I] and / or a cyclic aluminoxane compound represented by the following general formula [II]. During R ₂ Al-O-[Al (R) -O] _n -AlR ₂ ... [I] [Al (R) -O] _{n + 2} ... [II] the formulas, each R is either the same Can be different and have 1 carbon
To an alkyl group having 20 to 40 carbon atoms, an aryl group having 6 to 40 carbon atoms, an alkaryl group having 7 to 40 carbon atoms or an aralkyl group having 7 to 40 carbon atoms, preferably a methyl group, an ethyl group, and particularly preferably a methyl group. , N is an integer of 2 to 50, preferably 4 to 30. These aluminoxane compounds can be used alone or in combination of two or more kinds. Examples of the boron compound include trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate, tri-n-butylammonium tetraphenylborate, methyl (di-n-butyl) ammonium tetraphenylborate, and dimethylaniline tetraphenylborate. Aluminum, methylpyridinium tetraphenylborate, methyl tetraphenylborate (2-cyanopyridinium), methyl tetraphenylborate (4-cyanopyridinium), trimethylammonium tetrakis (pentafluorophenyl) borate, triethylammonium tetrakis (pentafluorophenyl) borate, Tetrakis (pentafluorophenyl)
Tri-n-butylammonium borate, methyl (di-n-butyl) ammonium tetrakis (pentafluorophenyl) borate, dimethylanilinium tetrakis (pentafluorophenyl) borate, methylpyridinium tetrakis (pentafluorophenyl) borate, tetrakis (pentafluoro) Phenyl) methyl borate (2-cyanopyridinium), tetrakis (pentafluorophenylphenyl) methyl borate (4-cyanopyridinium), tetrakis [bis (3,5-di-trifluoromethyl) phenyl] dimethylanilinium borate, tetraphenyl Examples thereof include, but are not limited to, ferrocenium borate, silver tetraphenylborate, and ferrocenium tetrakis (pentafluorophenyl) borate. These boron compounds can be used alone or in admixture of two or more.

Further, as the solvent used in the above-mentioned methods and, for example, hydrocarbon solvents such as n-pentane, n-hexane, n-heptane, n-octane, i-octane, cyclohexane, toluene and xylene; Examples thereof include halogenated hydrocarbon solvents such as methyl chloride, methylene chloride, chlorobenzene, etc., among which hydrocarbon solvents are preferable.

Copolymer rubber composition The weight ratio of the copolymer rubber (A) to the copolymer rubber (B) in the copolymer rubber composition of the present invention is 30/70 to 70/3.
0, preferably 50/50 to 70/30. In this case, if the weight ratio is less than 30/70, the high foamability, roll processability, Banbury processability, extrusion processability and the like of the copolymer rubber composition deteriorate, while if it exceeds 70/30, sponge rubber Shape retention, rigidity, etc. are reduced. More specifically, examples of the preferred copolymer rubber composition in the present invention are as follows (a) to (g). (A) A copolymer rubber composition in which the copolymer rubber (A) and the copolymer rubber (B) contain ENB as a non-conjugated diene. (B) A copolymer rubber composition in which the copolymer rubber (A) contains ENB and DCP or an α, ω-diene as a non-conjugated diene, and the copolymer rubber (B) contains ENB as a non-conjugated diene. (C) The DCP content of the copolymer rubber (A) is 3 in iodine value.
.About.20 or .alpha.,. Omega.-diene content is 0.05 to 5% by weight of all monomer components, and the total content of non-conjugated diene in the copolymer (A) is 35 to 50 in iodine value. The copolymer rubber composition according to (b) above, wherein the ENB content of the copolymer (B) is 3 to 20 in iodine value. (D) The copolymer rubber (A) contains ENB as a non-conjugated diene, and the copolymer rubber (B) is E as a non-conjugated diene.
A copolymer rubber composition containing NB and DCP or an α, ω-diene. (E) The ENB content of the copolymer (A) is 35 in iodine value.
Is 50 to 50, the DCP content of the copolymer rubber (B) is 0 to 10 in iodine value, or the α, ω-diene content is 0 to 2% by weight of all monomer components, and the copolymer (B The copolymerized rubber composition according to (d) above, wherein the total content of the non-conjugated dienes in 3) is 3 to 20 in iodine value. (F) The copolymer rubber (A) contains ENB and DCP or α, ω-diene as a non-conjugated diene, and the copolymer rubber (B) contains ENB and DCP or α, ω-diene as a non-conjugated diene. A copolymer rubber composition containing: (G) The copolymer rubber (A) contains ENB and DCP or an α, ω-diene as a non-conjugated diene, and the DCP content thereof is an iodine value of 3 to 20 or the α, ω-diene content is total. The total content of non-conjugated dienes in the copolymer rubber (A) is 0.05 to 5% by weight of the monomer component, and the iodine value is 35 to 35.
50, and the copolymer rubber (B) contains ENB and DCP or α, ω-diene as a non-conjugated diene, and the DCP content thereof is 0 to 10 or α, ω-diene content in iodine value. Is 0 to 2% by weight of the total monomer components, and the total content of the non-conjugated diene in the copolymer rubber (B) is 3 to 3 in iodine value.
20 is a copolymer rubber composition.

The copolymer rubber composition of the present invention can be prepared by various methods, examples of which are as follows:
The method of can be mentioned. A method of obtaining a solid rubber composition by mixing a solution of a copolymer rubber (A) and a solution of a copolymer rubber (B) and then removing a solvent, using two reaction tanks connected in series, The polymerized rubber (A) and the copolymerized rubber (B) are polymerized in the first reaction tank to produce, and the obtained copolymerized rubber is supplied to the second reaction tank, and the second reaction tank is supplied. A method for producing a solid rubber composition by removing the solvent after polymerizing the other copolymer rubber with, a copolymer rubber (A) and a copolymer rubber (B) in a solid state, respectively, in a Banbury mixer, Examples thereof include a method of obtaining a solid rubber composition by mixing using a usual kneader such as a roll mixer and an extruder. The copolymer rubber composition of the present invention contains a vulcanizing agent or a cross-linking agent (hereinafter, these are collectively referred to as "vulcanizing / cross-linking agent").
Say. ), A foaming agent, a filler, a softening agent, and the like to form a rubber compound, and then vulcanization / foaming is performed by a commonly used method to produce a sponge rubber.
Examples of the vulcanizing / crosslinking agent include sulfur such as powdered sulfur, precipitated sulfur, colloidal sulfur and insoluble sulfur; inorganic vulcanizing agents such as sulfur chloride, selenium and tellurium; morpholine disulfides, alkylphenol disulfides, thiuram disulfides. , Sulfur-containing organic compounds such as dithiocarbamates; 1,1-di-t-butylperoxy-3,3
5-trimethylcyclohexane, di-t-butyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 1,3-bis Examples thereof include organic peroxides such as (t-butylperoxy-i-propyl) benzene. These vulcanizing / crosslinking agents may be used alone or in admixture of two or more. The blending amount of the vulcanizing / crosslinking agent varies depending on the type,
For example, in the case of sulfur, it is usually 0.1 to 10 parts by weight, preferably 0.5 to 100 parts by weight of the copolymer rubber composition.
In the case of an organic peroxide, it is usually 0.1 to 10 parts by weight, preferably 0.5 to 8 parts by weight with respect to 100 parts by weight of the copolymer rubber composition. When sulfur is used as the vulcanization / crosslinking agent, a vulcanization accelerator and a vulcanization acceleration aid can be further added, if necessary. Examples of such vulcanization accelerators include aldehyde ammonias such as hexamethylenetetramine; diphenylguanidine,
Guanidines such as di (o-tolyl) guanidine and o-tolyl-biguanide; thioureas such as thiocarbanilide, di (o-tolyl) thiourea, N, N'-diethylthiourea, tetramethylthiourea, trimethylthiourea and dilaurylthiourea Mercaptobenzothiazole, dibenzothiazole disulfide, 2- (4-
Morpholinothio) benzothiazole, 2- (2,4-
Dinitrophenyl) mercaptobenzothiazole, N,
Thiazoles such as N ′-(diethylthiocarbamoylthio) benzothiazole; Nt-butyl-2-benzothiazylsulfenamide, N, N′-dicyclohexyl-2-benzothiazylsulfenamide, N, N Sulfenamides such as'-di-i-propyl-2-benzothiazylsulfenamide and N-cyclohexyl-2-benzothiazylsulfenamide; tetramethylthiuram disulfide, tetraethylthiuram disulfide,
Thiurams such as tetrabutyl thiuram disulfide, tetramethyl thiuram monosulfide, dipentamethylene thiuram tetrasulfide; zinc dimethyl (di) thiocarbamate, zinc diethyl (di) thiocarbamate, di-n-butyl (di) thiocarbamine Zinc acid, zinc ethylphenyl (di) thiocarbamate, sodium dimethyl (di) thiocarbamate, copper dimethyl (di) thiocarbamate, tellurium dimethyl (di) thiocarbamate, iron dimethyl (di) thiocarbamate, etc. (Di) thiocarbamate salts; xanthate salts such as zinc n-butyl thioxanthate and the like can be mentioned. These vulcanization accelerators may be used alone or in admixture of two or more. The compounding amount of the vulcanization accelerator is usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the copolymer rubber composition. Examples of the vulcanization accelerator include metal oxides such as magnesium oxide, zinc white, litharge, red lead, and lead white; organic acids (salts) such as stearic acid, oleic acid, and zinc stearate. In particular, zinc white and stearic acid are preferable. These vulcanization accelerating aids can be used alone or in admixture of two or more. The compounding amount of the vulcanization acceleration aid is usually 3 to 20 parts by weight with respect to 100 parts by weight of the copolymer rubber composition. When organic peroxides are used as the vulcanizing / crosslinking agent, a crosslinking aid can be further added if necessary. Examples of such a cross-linking aid include sulfur and sulfur or sulfur compounds such as dipentamethylene thiuram tetrasulfide; polyethylene dimethacrylate, divinylbenzene, diallyl phthalate, triallyl cyanurate, metaphenylene bismaleimide, toluylene bismaleimide, etc. And polyfunctional monomers; oxime compounds such as p-quinone oxime and p, p′-benzoylquinone oxime. These cross-linking aids can be used alone or in admixture of two or more. Examples of the foaming agent include inorganic foaming agents such as ammonium carbonate, sodium bicarbonate, and anhydrous sodium nitrate; dinitrosopentamethylenetetramine, N, N′-dimethyl-N, N′-dinitrosoterephthalamide, benzenesulfonylhydrazide, and the like. p,
p'-oxybis (benzenesulfonyl hydrazide),
3,3′-disulfone hydrazide diphenyl sulfone,
Organic foaming agents such as azoisobutyronitrile and azobisformamide can be mentioned. These foaming agents may be used alone or in admixture of two or more.
Further, together with the foaming agent, a foaming auxiliary agent such as urea-based, organic acid-based or metal salt-based foaming agent can be used. The blending amount of the foaming agent and the foaming auxiliary agent is such that the foaming agent is the copolymer rubber composition 1
The amount is usually 0.5 to 20 parts by weight, preferably 1 to 15 parts by weight, based on 00 parts by weight, and the foaming aid is usually 1 to 20 parts by weight, based on 100 parts by weight of the copolymer rubber composition. Parts by weight. Examples of the filler include SRF and FE
Carbon blacks such as F, HAF, ISAF, SAF, FT and MT; inorganic fillers such as fine particle silicic acid, calcium carbonate, magnesium carbonate, clay and talc are preferable. These fillers can be used alone or in admixture of two or more. The amount of the filler compounded is usually 50 to 20 with respect to 100 parts by weight of the copolymer rubber composition.
0 parts by weight. Examples of the softening agent include process oils such as aromatic oils, naphthenic oils and paraffin oils commonly used for rubber; vegetable oils such as coconut oil. Process oils are preferable, and paraffin oils are particularly preferable. These softening agents may be used alone or in admixture of two or more. The blending amount of the softening agent is 100 parts by weight of the copolymer rubber composition.
Usually, it is 30 parts by weight or more. Furthermore, the copolymer rubber composition of the present invention includes a reinforcing material, a hygroscopic agent, a plasticizer, an antioxidant, an antioxidant, a heat stabilizer, an ultraviolet absorber, a lubricant, a release agent, a flame retardant, an antistatic agent. Further, other additives such as dyes and pigments, and other rubber-like or resin-like polymers can be blended. Examples of the other polymer include butyl rubber, natural rubber, polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, ethylene-α-other than copolymer rubber (A) and copolymer rubber (B). Examples thereof include olefin-non-conjugated diene copolymer, ethylene-α-olefin copolymer, polyethylene and polypropylene. These other polymers may be used alone or in admixture of two or more. The blending method and blending order of the above-mentioned various additives to the copolymer rubber composition of the present invention are not particularly limited, and known kneaders, extruders and the like can be used, but usually a Banbury mixer. And so on,
After mixing the copolymer rubber (A), the copolymer rubber (B), the filler, the softening agent and the like, a roll mixer is used to mix the vulcanizing / crosslinking agent, the foaming agent and the like. Then, according to the procedure generally used for the production of sponge rubber, for example, a method of heating a rubber compound in a mold of a known vulcanizing / foaming device to vulcanize / foam, or an extruder for molding the rubber compound. A desired sponge rubber can be produced by a method of continuously molding in a vulcanization tank after molding it into a desired shape using. The heating temperature and heating time during vulcanization / foaming vary depending on the type of the vulcanizing agent or the foaming agent, the degree of foaming, etc., but the heating temperature is usually 150 to 280 ° C., preferably 180 to 280 ° C.
250 ° C., and the heating time is usually 2 to 15 minutes,
It is preferably 3 to 10 minutes.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to examples. However, the present invention is not limited to these examples. Each measurement / evaluation in Examples and Comparative Examples was performed according to the following procedures. (1) Propylene content (% by weight) It was measured by an infrared absorption spectrum method. (2) Iodine value Measured by infrared absorption spectroscopy. (3) Mooney viscosity The measurement temperature was 120 ° C., the residual heat time was 1 minute, and the time until the viscosity was read was 8 minutes. (4) Molecular weight distribution (Mw / Mn) It was measured by the following procedure by gel permeation chromatography (GPC). (I) Polystyrene with known molecular weight (Toyo Soda Co., Ltd.)
"Mono-dispersed polystyrene"), and the concentration is 0.02
GPC (Gel Permiation Chromatograph) as weight%
The count is measured, and a correlation diagram calibration curve of its molecular weight M (Mw and Mn) and EV (Elution Volume) is prepared. (Ii) The GPC count of the sample is measured, Mw and Mn of the sample are obtained from the correlation diagram calibration curve, and the molecular weight distribution (Mw / Mn) is calculated. The sample preparation and GPC measurement in this case were performed as follows. Sample preparation (a) After the sample was collected into an Erlenmeyer flask together with o-dichlorobenzene so as to have a concentration of 0.15% by weight,
An antioxidant (2,6-di-t-butyl-p-cresol) is added in an amount of 0.08% by weight based on the total amount of the sample and the solvent. (B) This Erlenmeyer flask is heated to 135 ° C.
After stirring for a minute to dissolve the sample, it is filtered. (C) This filtrate is subjected to GPC measurement. GPC measurement (a) device: Water (Water) 150CV
Type (b) Column: SHODEX × 4 (c) Sample solution amount: 500 μl (d) Temperature: 135 ° C. (v) Flow rate: 1 ml / min (5) Branch index g ′ Intrinsic viscosity of sample ([η] obs) and a linear ethylene-
Intrinsic viscosity formula determined for propylene copolymer (EPM)

Embedded image (However, M is the molecular weight of EPM, K = 0.040356, α = 0.30
89. ), And the intrinsic viscosity ([η] liner) obtained by substituting the Mw of the sample measured in (4) above, it was determined by the equation g ′ = [η] obs / [η] liner. (6) Ethylene crystal melting point (° C.) Using DSC220C manufactured by Seiko Denshi KK, heating from room temperature to 160 ° C. at a heating rate of 20 ° C./min to 160 ° C.
At 10 ° C./min for 10 minutes, then at −110 ° C. for 10 minutes and then again heated at 20 ° C./min to 160 ° C. According to the endothermic peak during the second heating, JIS K
The melting point was determined according to 7121. (7) Extrudability (Garbedy score) The extrudability was evaluated according to the ASTM-D2230A method. (8) Shape retention (%) An unvulcanized rubber compound was extruded using a die having a shape shown in FIG. 1, and this molded product was left to stand horizontally in an atmosphere of 220 ° C. for 7 minutes, and then the vertical dimension was measured. Ratio of La to lateral dimension Lb (L
It was evaluated by a / Lb) × 100. (9) Physical properties of sponge (a) Specific gravity The sponge was measured in accordance with the standard specifications of the Japan Rubber Association and the physical test method for expanded rubber. (B) Compression set (%) According to JIS K6301, a molded product extruded using a die having a shape shown in FIG. 1, vulcanized and foamed, is subjected to a compression strain of 50% in the longitudinal direction of FIG. Then, the compression strain was measured after 22 hours at 70 ° C. and after 200 hours at 70 ° C. (C) Rigidity Sponge rubber is punched into a test piece of 100 mm x 5 mm x about 2 mm, and 25% is stipulated in accordance with JIS K6301.
The extension stress (kPa) was measured to evaluate the rigidity. (D) Sponge surface skin: Based on the smoothness of the surface of the sponge rubber, the presence of gloss, the presence or absence of tackiness, etc., it was visually evaluated in three grades of excellent, good and poor. (10) Gelation time (second) Using a sample prepared by kneading the rubber compound shown in [I] of Table 1,
13 using a stress relaxation measuring device (JSR Elastograph manufactured by Japan Synthetic Rubber Co., Ltd., Japanese Patent Publication No. 5-25059)
At 0 ° C. and a shear strain rate of 20 per second, the time at which the torque started to rise was measured and used as the gel time.

[0018]

【Example】

Examples 1 to 3 and Comparative Examples 1 to 9 Using the copolymer rubbers shown in Table 2 to Table 5, the components shown in [I] of Table 1 were set at a temperature of 50 ° C. in a BR type Banbury mixer (content 1 Rotation speed 60r
The mixture was kneaded at pm for 5 minutes to obtain a compound (I). To this compound (I), the components shown in [II] of Table 1 were blended and kneaded for 5 minutes with a 10 inch roll mixer maintained at 50 ° C. to obtain compound (II). After that, put it in a 50 mm extruder and put it on
0 compliant), with a cylinder temperature of 60 ° C,
The die temperature was set at 80 ° C. and the screw rotation speed was set at 30 rpm, and the compound (II) was extruded to evaluate the extrudability. A 50 mm extruder equipped with a die having the shape shown in FIG. 1 has a cylinder temperature of 60 ° C. and a die temperature of 80.
After extruding the compound (II) at a temperature of 30 ° C. and a screw rotation speed of 30 rpm, the compound (II) was heated in a hot air bath at 200 ° C. for 10 minutes for vulcanization and foaming to obtain a sponge rubber. The evaluation results of the obtained sponge rubber are shown in Table 2.
~ Shown in Table 5. As a result, the copolymer rubber composition of the present invention has a high foaming property, a small sponge specific gravity, no decrease in rigidity, excellent extrusion processability, good shape retention, and a small compression set. Moreover, the gelation time was long. In contrast, the copolymer rubber composition of Comparative Example 1 had a low ethylene crystal melting point of the high molecular weight copolymer rubber, insufficient crystallinity, low rigidity, and poor extrusion processability. Since the copolymer rubber composition of Comparative Example 2 has a low iodine value like a low molecular weight copolymer rubber, it has a large sponge specific gravity, is inferior in shape retention, has a large compression set, and has a bad sponge surface due to gas escape. It was In the copolymer rubber composition of Comparative Example 3, the low molecular weight copolymer rubber had a high Mooney viscosity, so that the sponge specific gravity was large, the extrusion processability was poor, and the gelation time was short. The copolymer rubber composition of Comparative Example 4 is
Since the propylene content of the high molecular weight copolymer rubber was high, the crystallinity was insufficient and the rigidity was low. The copolymer rubber composition of Comparative Example 5 was inferior in shape retention, had a large compression set, and had a poor sponge surface texture due to gas release because the Mooney viscosity of the high molecular weight copolymer rubber was low. Comparative Example 6
The copolymer rubber composition of Example 2 has a composition that is almost the same as the average composition of the copolymer rubber composition of Example 2, but unlike the copolymer rubber composition of the present invention, it is composed of a single copolymer rubber, and therefore has a sponge specific gravity of Was large, the extrusion processability and the shape retention were poor, and the gelation time was short. The copolymer rubber composition of Comparative Example 7 had a high weight ratio of the low molecular weight copolymer rubber and the high molecular weight copolymer rubber, and thus had high rigidity, poor shape retention, and poor sponge surface texture. In the copolymer rubber composition of Comparative Example 8, the weight ratio of the low molecular weight copolymer rubber and the high molecular weight copolymer rubber was small, so that high foaming was not possible and the extrusion processability was poor. Further, the copolymer rubber composition of Comparative Example 9 was poor in extrusion processability and shape retention because the branching index g'of the low molecular weight copolymer rubber was large, and the surface of the sponge was poor due to gas release.

[0019]

[Table 1]

In Table 1, (* 1) to (* 10) are as follows. (* 1) Asahi Carbon Co., Ltd. Asahi 50HG (* 2) Idemitsu Kosan Co., Ltd. Diana Process Oil PW
-380 (* 3) Vesta PP (* 4) Mercaptobenzothiazole (* 5) Zinc dimethyldithiocarbamate (* 6) Zinc di-n-butyldithiocarbamate (* 7) Dipentamethylene thiuram tetra Sulfide (* 8) Tetraethylthiuram disulfide (* 9) Morpholine disulfide (Ouchi Shinko Chemical Co., Ltd.)
(* 10) p, p'-oxybis (benzenesulfonylhydrazide)

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

[0024]

[Table 5]

[0025]

EFFECT OF THE INVENTION The copolymer rubber composition of the present invention has a high foaming property, and when it is highly foamed, the rigidity is not particularly lowered, the compression set and surface texture of sponge rubber are excellent, and the vulcanization is excellent.・ Excellent shape retention during foaming, less amount of "bugs" and "gels" generated during kneading and extrusion, no edge breakage during extrusion, excellent kneading processability, extrusion processability, etc. Easy to pelletize. Therefore, the copolymer rubber composition of the present invention can be used very preferably as a sponge rubber, particularly as a sealing material for automobile door seals, roof side rails, trunk seals, etc., as well as civil engineering / construction sealing materials, It is useful for a wide range of applications including sealing materials for machinery and equipment, wire coating materials, etc.

[Brief description of drawings]

FIG. 1 is a view showing the shape of a die used for evaluation of shape retention and compression set.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsumi Oka 2-11-24 Tsukiji, Chuo-ku, Tokyo Within Nippon Synthetic Rubber Co., Ltd. (72) Yoji Mori 2-11-24 Tsukiji, Chuo-ku, Tokyo Within Nippon Synthetic Rubber Co., Ltd.

Claims (1)

[Claims] 1. A weight ratio of ethylene / α-olefin (A) is 40/60 to 70/30 and iodine value is 35 to 50.
And a branching index g ′ of 0.
5 to 0.9 and the Mooney viscosity (ML _{1 + 8} 120
(C) 20 to 65 ethylene-α-olefin-non-conjugated diene copolymer, and (B) ethylene / α-olefin weight ratio of 70/30 to 90/10 and iodine value of 3 to 20. The amount of non-conjugated diene contained in the crystalline portion is 40-300, and the Muni-viscosity (ML _{1 + 8} 120 ° C.) is 65 to 300.
An ethylene-containing ethylene-α-olefin-non-conjugated diene copolymer having a temperature of ℃ or more, wherein the weight ratio of the component (A) and the component (B) is 30/70 to 70/30. α-Olefin-non-conjugated diene copolymer rubber composition.