JP5476172B2 - Flame-retardant rubber composition and rubber molded body - Google Patents

Description

  The present invention relates to a rubber composition and a rubber molded product obtained by crosslinking and foaming the rubber composition. More specifically, the present invention relates to a rubber composition exhibiting a sufficiently high foaming property, and more specifically, to a low specific gravity rubber molded article having high flame retardancy and excellent surface smoothness.

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

  One of these applications is a coated sponge used for the purpose of heat insulation and prevention of breakage of refrigeration, refrigerant piping, cold / hot pipes, and tube materials. Since these coated sponges are often used as building materials, high flame resistance is required from the viewpoint of fire spread, and more recently, the surface needs to be coated to give strength and slidability. It is also strongly desired to have excellent properties.

  In order to obtain a highly heat-insulating coated sponge, it is necessary to lower the specific gravity of the sponge. On the other hand, in order to obtain high flame retardancy, it is necessary to add a large amount of a flame retardant such as a metal oxide, a phosphorus compound, a halogen compound, or a silicone compound because an olefin polymer such as EPDM easily burns. As a result, it is difficult to achieve high foaming, and the foam appearance deteriorates.

  Patent Document 1 describes that a sponge having low specific gravity and flame retardancy can be obtained by blending a large amount of flame retardant using specific EPDM. However, regarding the surface appearance, only abnormal foaming by sensory evaluation is described, and surface smoothness is not specified.

  Moreover, as a method of obtaining a rubber foam having flame retardancy and low specific gravity, (1) a method of blending calcium carbonate and a hydrated inorganic filler in EPDM, (2) a blend of hydrated metal oxide and expansive graphite Patent Documents 2 to 5 describe a method for blending, (3) a method for blending a hydrated metal compound with ammonium polyphosphate, a melamine flame retardant, and pophenylene oxide, and (4) a method for blending decabromodiphenyl ether. However, in any method, it is difficult to improve the external appearance, and it has not been known so far that the foaming property and the external appearance are compatible with the formulation.

  On the other hand, as a method of obtaining a rubber foam having a good appearance, diene rubber such as NBR or SBR, which has a much faster vulcanization speed than EPDM, is used as a raw rubber, and the surface layer is quickly cross-linked, thereby smoothing the surface. A foam having excellent properties can be obtained. However, when a diene rubber is used, a coated sponge excellent in appearance using EPDM as a raw material rubber has been strongly desired due to problems such as poor heat resistance and ozone resistance and restrictions on outdoor use.

JP2007-204621 JP 2001-288292 A JP2002-128932 JP2002-293976 JP2007-21111

  The present invention is intended to solve the problems associated with the prior art as described above, and has a rubber composition having a sufficiently high foamability and a high degree of difficulty obtained by crosslinking and foaming the rubber composition. It aims at providing the low specific gravity rubber molding which has flammability and is excellent in surface smoothness.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have obtained an ethylene / α-olefin / non-conjugated diene random copolymer obtained by copolymerizing a specific diene using a metallocene catalyst. A rubber composition containing a flame retardant, a filler, a softener and a foaming agent in a specified ratio has sufficient foaming properties, and a rubber molded body obtained from the rubber composition has a high flame retardancy. The present invention was completed by finding that it has a low specific gravity and excellent surface appearance.

  That is, the rubber composition of the present invention comprises the following ethylene / α-olefin / non-conjugated diene random copolymer [I], vinyl chloride resin and / or flame retardant [II], softener [III], and foam. The content of [I], [II] and [III] satisfies the relational expression of formula (ii), and the foaming agent is 5 to 50 weights per 100 parts by weight of the copolymer [I]. It is characterized by containing a part.

Copolymer [I]: Ethylene [A], α-olefin [B] having 3 to 20 carbon atoms, one molecule of carbon / carbon double bond that can be polymerized with a metallocene catalyst among carbon / carbon double bonds Non-conjugated polyene [C-1] having only one carbon atom in the molecule and non-conjugated polyene having two carbon-carbon double bonds polymerizable with a metallocene catalyst among two carbon-carbon double bonds in one molecule [ A copolymer synthesized using a metallocene catalyst, comprising a structural unit derived from C-2],
(1) The structural unit derived from an α-olefin [B] having 3 to 20 carbon atoms is 10 to 50 mol% in 100 mol% of all structural units,
(2) Mol% of structural units derived from non-conjugated polyene [C-1] in which only one carbon / carbon double bond that can be polymerized with a metallocene catalyst is present in one molecule. And a total of mol% of structural units derived from non-conjugated polyene [C-2] in which two carbon / carbon double bonds that can be polymerized with a metallocene catalyst are present in one molecule. 1.0 to 6.0 mol%,
(3) Mol% of structural units derived from non-conjugated polyene [C-1] in which only one carbon / carbon double bond that can be polymerized with a metallocene catalyst is present in one molecule. Of carbon and carbon double bonds that can be polymerized with a metallocene catalyst among the carbon and carbon double bonds and the mol% of the structural unit derived from non-conjugated polyene [C-2] that exists in one molecule ([C-1] / [C-2]) is 75/25 to 99.5 / 0.5,
(4) Mooney viscosity [ML _{1 + 4} (100 ° C.)] measured at 100 ° C. is 10 to 90,
(5) The apparent iodine value (IV) of the structural unit derived from the non-conjugated polyene [C-2] is 0.1 to 3.0 g / 100 g,
(6) A copolymer satisfying the following formula (i).
50> Flow activation energy (Ea) [KJ / mol]> 35 (i)
(Vinyl chloride resin and / or flame retardant [II]) / (copolymer [I] + softener [III]) ≧ 1.50 (ii)
Among the carbon-carbon double bonds, a non-conjugated polyene [C-1] in which only one carbon-carbon double bond polymerizable with a metallocene catalyst exists in one molecule is 5-ethylidene-2-norbornene (ENB). Non-conjugated polyene [C-2] in which two carbon / carbon double bonds polymerizable with a metallocene catalyst are present in one molecule among the carbon / carbon double bonds is 5-vinyl-2- Norbornene (VNB) is a preferred embodiment in terms of polymerizability and crosslinking reactivity with a metallocene catalyst.

  It is a preferable embodiment in terms of productivity that the copolymer [I] is synthesized using a catalyst having a structure represented by the following formula (iii ′).

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

  The crosslinked foam obtained by crosslinking and foaming the rubber composition of the present invention has a specific gravity of 0.03 to 0.3, preferably 0.05 to 0.28, and the surface roughness of the foam is 30 μm. The flame retardant crosslinked foam is preferably 25 μm or less, more preferably 20 μm or less. “Flame retardancy” means a level that passes the HF-1 grade in the HBF test based on the UL94 standard.

  The rubber composition of the present invention has a sufficiently high foaming property, and a low specific gravity rubber molded article having high flame retardancy and excellent surface smoothness is obtained by crosslinking and foaming the rubber composition. Can do.

  Since the rubber molded body is a low specific gravity molded body having flame retardancy and excellent surface smoothness, a coated sponge used for heat insulation and damage prevention of pipes, pipes and tubes, and automobile seals It can be suitably used for a sponge.

Hereinafter, the rubber composition and the rubber foam according to the present invention will be specifically described.
[Ethylene / α-olefin / non-conjugated polyene copolymer rubber [I]]
The copolymer of the present invention has 1 carbon / carbon double bond that can be polymerized with a metallocene catalyst among ethylene [A], α-olefin [B] having 3 to 20 carbon atoms, and carbon / carbon double bond. Non-conjugated polyene [C-1] in which only one is present in the molecule and non-conjugated polyene in which two carbon / carbon double bonds that can be polymerized with a metallocene catalyst are present in one molecule. A copolymer synthesized using a metallocene catalyst, including a structural unit derived from [C-2], wherein (1) the structural unit derived from an α-olefin [B] having 3 to 20 carbon atoms 10% to 50% by mole in 100% by mole of all structural units, and (2) only one carbon / carbon double bond that can be polymerized with a metallocene catalyst is present in one molecule. The structural unit derived from the non-conjugated polyene [C-1] % Of the structural unit derived from the non-conjugated polyene [C-2] in which two carbon-carbon double bonds polymerizable with a metallocene catalyst are present in one molecule. The total amount is 1.0 to 6.0 mol%, and (3) non-conjugate in which only one carbon / carbon double bond that can be polymerized with a metallocene catalyst is present in one molecule. Non-conjugated polyene [C] having two carbon / carbon double bonds that can be polymerized with a metallocene catalyst among the mole% of structural units derived from polyene [C-1] and carbon / carbon double bonds -2] is a ratio ([C-1] / [C-2]) with the mol% of structural units derived from 75 / 25-99.5 / 0.5, and (4) measured at 100 ° C. that Mooney viscosity _{[ML 1 + 4 (100 ℃} )] is 10 to 90, to meet the (5) formula (I) And butterflies.
50> Flow activation energy (Ea) [KJ / mol]> 35 (I)

  In addition, in this specification, said (1)-(5) is also described as requirements (1)-(5), respectively. The copolymer of the present invention has 1 carbon / carbon double bond that can be polymerized with a metallocene catalyst among ethylene [A], α-olefin [B] having 3 to 20 carbon atoms, and carbon / carbon double bond. Non-conjugated polyene [C-1] in which only one is present in the molecule and non-conjugated polyene in which two carbon / carbon double bonds that can be polymerized with a metallocene catalyst are present in one molecule. [C-2] is a copolymer having a structural unit derived from the raw material.

  In the present specification, ethylene [A] can be polymerized by component [A], α-olefin [B] having 3 to 20 carbon atoms can be polymerized by component [B], and a metallocene catalyst among carbon / carbon double bonds. Non-conjugated polyene [C-1] in which only one carbon / carbon double bond exists in one molecule is component [C-1], and carbon / carbon that can be polymerized with a metallocene catalyst among carbon / carbon double bonds Non-conjugated polyene [C-2] having two double bonds in one molecule is also referred to as component [C-2].

[Component [B]]
Specific 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- Examples include octene, 1-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 of this invention contains the structural unit derived from an at least 1 sort (s) of C3-C20 alpha-olefin [B], and has 2 or more types of C3-C20 alpha-. A structural unit derived from olefin [B] may be included.

[Component [C-1]]
Among the carbon-carbon double bonds, as the non-conjugated polyene [C-1] in which only one carbon-carbon double bond polymerizable with a metallocene catalyst exists in one molecule, both ends are vinyl groups (CH ₂ = CH-) is not included, one carbon-carbon double bond is present as a vinyl group at the end of the molecule, and the other carbon-carbon double bond (C = C) is a molecule It is preferably present in the form of an internal olefin structure in the chain (including the main chain and side chain). Examples of component [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, 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-propiene -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, Examples include 8-decadiene, 6-methyl-1,6-undecadiene, 9-methyl-1,8-undecadiene, and the like. 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.

  The alicyclic polyene is composed of an alicyclic portion having one carbon / carbon double bond (unsaturated bond) and a chain portion having an internal olefin bond (carbon / carbon double bond). Specific examples thereof include 5-ethylidene-2-norbornene (ENB), 5-propylidene-2-norbornene, 5-butylidene-2-norbornene, and the like. 5-ethylidene-2-norbornene (ENB) ) Is preferably used. Specific examples of the other alicyclic polyenes include 2-methyl-2,5-norbornadiene and 2-ethyl-2,5-norbornadiene.

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

[Component [C-2]]
As a specific example of the non-conjugated polyene [C-2] in which two carbon / carbon double bonds polymerizable with a metallocene catalyst among the carbon / carbon double bonds exist in one molecule, 5-vinyl-2 - norbornene (VNB), 5-allyl-2-norbornene and the like of 5-alkenyl-2-norbornene; 2,5-norbornadiene, dicyclopentadiene (DCPD), norbornadiene, tetracyclo [4,4,0,1 ^2.5, 1 ^7.10 ] Alicyclic polyenes such as deca-3,8-diene; α, ω-dienes such as 1,7-octadiene and 1,9-decadiene, and the like.

  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 of this invention contains the structural unit derived from at least 1 sort (s) of component [C-2], and may contain the structural unit derived from 2 or more types of components [C-2]. Good.

[Requirement (1)]
In the copolymer of the present invention, the structural unit derived from the α-olefin [B] having 3 to 20 carbon atoms is 10 to 50 mol%, preferably 25 to 45 mol in 100 mol% of all structural units. %.

  When the structural unit (mol%) derived from the component [B] is in the above range, the viewpoint of flexibility and low-temperature mechanical properties of the crosslinked foam obtained from the rubber composition containing the copolymer of the present invention. To preferred.

The molar ratio can be determined by ¹³ C-NMR.

[Requirement (2)]
The copolymer of the present invention is derived from a non-conjugated polyene [C-1] in which only one carbon / carbon double bond that can be polymerized with a metallocene catalyst is present in one molecule. Of the structural units derived from non-conjugated polyene [C-2] in which two moles of structural units and two carbon / carbon double bonds that can be polymerized with a metallocene catalyst are present in one molecule. The total of mol% is 1.0 to 6.0 mol%. The total of the mol% is preferably 1.0 to 5.0 mol%.

  It is preferable that the total of the mol% is within the above range because the vulcanization reaction rate can be controlled relatively easily.

In addition, the sum total of the said mol% can be calculated | required by totaling the molar amount of ENB and VNB calculated | required by < ¹³ > C-NMR.

[Requirement (3)]
The copolymer of the present invention is derived from a non-conjugated polyene [C-1] in which only one carbon / carbon double bond that can be polymerized with a metallocene catalyst is present in one molecule. Of structural units derived from non-conjugated polyene [C-2] in which two carbon / carbon double bonds that can be polymerized with a metallocene catalyst are present in a molecule, out of the mole% of structural units and carbon / carbon double bonds. The ratio ([C-1] / [C-2]) to mol% is 75/25 to 99.5 / 0.5. The ratio of the mol% of the structural unit derived from the component [C-1] and the mol% of the structural unit derived from the component [C-2] is preferably 78/22 to 97/3.

  When the ratio between the mol% of the structural unit derived from the component [C-1] and the mol% of the structural unit derived from the component [C-2] is within the above range, the vulcanization reactivity and the foaming reaction This is preferable because of excellent balance of gas retention.

The ratio of the mol% of the structural unit derived from the component [C-1] and the mol% of the structural unit derived from the component [C-2] can be determined by ¹³ C-NMR.

  Hereinafter, a copolymer obtained from ethylene, propylene, 5-ethylidene-2-norbornene (ENB) and 5-vinyl-2-norbornene (VNB), which are copolymers of the present invention, will be taken as an example, and requirements (1 ) To (3) are specifically shown.

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 ethylene chain-derived peak + {Integral value of ethylene-propylene chain-derived peak} / 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 position peak 4) VNB: integrated value of VNB-7 position peak Chemical formula of structure (E-form, Z-form) derived from ENB in the copolymer of the present invention and VNB The chemical formula of the 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 performed 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 (4)]
The copolymer of the present invention has a Mooney viscosity [ML _{1 + 4} (100 ° C.)] measured at 100 ° C. of 10 to 90. The Mooney viscosity is preferably 10-80.
When the Mooney viscosity is within the above range, the rubber compound viscosity as a foaming medium can be set relatively easily, and a blending design excellent in kneadability is possible, which is preferable.
The Mooney viscosity can be measured according to JIS K6300 using a Mooney viscometer (SMV202 type manufactured by Shimadzu Corporation).

[Requirement (5)]
The copolymer of the present invention satisfies the following formula (I), and preferably satisfies the following formula (I ′).
50> Flow activation energy (Ea) [KJ / mol]> 35 (I)
50> Flow activation energy (Ea) [KJ / mol]> 37 (I ') Generally, the viscosity of a polymer melt decreases with increasing temperature, like the viscosity of a simple rheological liquid. At a high temperature (Tg; glass transition temperature + 100 ° C.), it is known that the temperature dependence of the viscosity follows the Arrhenius type equation represented by the following equation (A).
Viscosity (ηo) = Aexp (Ea / RT) (A)
R: Gas constant, A: Frequency factor, Ea: Flow activation energy, T: Absolute temperature Since the flow activation energy does not depend on the molecular weight and molecular weight distribution but is influenced only by the molecular structure, the structure of the polymer It is a useful index that represents information.

  However, it is difficult to precisely control the molecular structure of an olefin polymer obtained using a Ziegler catalyst, and various structural information has been calculated by being included in the flow activation energy. In recent years, with the discovery of metallocene catalysts and advances in manufacturing technology, it has become possible to control molecular weight distribution, short chain branching degree, composition distribution and long chain branching degree, and the activation energy of flow of high density polyethylene (LDPE) is About 27 kJ / mol, the activation energy of the flow of low density polyethylene (LDPE) is reported to be about 56 kJ / mol. The difference in flow activation energy here is thought to be due to long-chain branching, but long-chain branching analysis can be accurately detected, although methods that are evaluated by NMR or light scattering are known. It is difficult, and research that focuses on rheological properties is still actively conducted (Reference 1; Masayuki Yamaguchi, Molding, Vol. 20, No. 7, 400-404 (2008), Reference 2 FJ Stadler, C. Gabriel, H. Munstedt, Macromolecular chemistry and Physics, 208, 2449-2454 (2007)).

  On the other hand, in EPDM, it has been reported that the distribution of diene components copolymerized as crosslinking sites is uniformized by using a metallocene catalyst (Reference 3; BA Harrington, MG Williams, Presented at a meeting of the Rubber Division). , American Chemical Society October, 14-17 (2003)).

  Therefore, by using a metallocene catalyst, it is possible to control the precise molecular structure of EPDM and to uniformize the cross-linking reactivity, and to grasp the relationship between the activation energy of the flow and the physical properties of the rubber composition and cross-linked foam. It has become possible to specify structural regions that express superior functions in the region.

  In general, in order to prepare a crosslinked foamed product by crosslinking and foaming a composition containing ethylene / propylene / diene copolymer rubber (EPDM), the properties of the composition, vulcanization reaction and foaming reaction are controlled. It is important to.

  For example, if the viscosity of the composition is too low, the retention of foaming gas is poor, the specific gravity cannot be lowered, and the appearance is further deteriorated. On the other hand, if the viscosity of the composition is too high, foaming will not occur. Further, as one of the factors affecting the viscosity of the composition, there is a network formation by a crosslinking reaction of EPDM, and the control of the crosslinking reaction is also important.

  Therefore, in the past, in order to improve the retention of foaming gas under the condition where the viscosity of the composition is lowered, the molecular design is made to widen the molecular weight distribution of EPDM, and the study to improve the gas retention by the high molecular weight component. Has been done. On the other hand, polyethylene is well known for improving gas retention by introducing long-chain branches into the polymer, but it is difficult to introduce long-chain branches with EPDM using conventional Ziegler catalysts. Furthermore, in the Ziegler catalyst, it is difficult to uniformly introduce the diene component into the polymer, and the cross-linking reaction is unevenly distributed. As a result, it is difficult to obtain a sufficiently high foam.

  Therefore, the copolymer of the present invention is synthesized using a metallocene catalyst to uniformly introduce the diene component into the polymer, control the crosslinking reaction, and as one of the diene components, 5-vinyl- By copolymerizing the component [C-2] such as 2-norbornene (VNB), more long chain branches were introduced, and the structural characteristics were specified by the activation energy of flow. The cross-linked foam of the present invention obtained by cross-linking and foaming the composition containing the copolymer of the present invention, whose flow activation energy satisfies the above formula (I), has been difficult to achieve until now. It became possible to prepare the body easily and stably. Moreover, it discovered that the crosslinked foam obtained by the composition containing the copolymer of this invention showed the surface smoothness which was remarkably excellent.

  The flow activation energy (Ea) of the copolymer of the present invention depends on the frequency (unit: Hz) of the melt complex viscosity (unit: Pa · sec) at 190 ° C. based on the temperature-time superposition principle. It is a numerical value calculated by the Arrhenius equation from the shift factor (aT) when creating the master curve showing the property, and is obtained by the following method.

That is, the melt complex viscosity-frequency curve (unit of melt complex viscosity; Pa / sec, unit of frequency; Hz) of the copolymer at temperatures of 170 ° C. and 210 ° C. (T, unit; ° C.) Based on the principle of superposition, for each melt complex viscosity-frequency curve at each temperature (T), each temperature (T) obtained when superposed on the melt complex viscosity-frequency curve of the copolymer at 190 ° C. ) Is used to calculate a first-order approximate expression (formula (I) below) of [ln (aT)] and [1 / (T + 273.16)] by the method of least squares. Next, Ea is obtained from the slope m of the linear expression and the following expression (II).
ln (aT) = m (1 / (T + 273.16)) + n (I)
Ea = [0.008314 × m] (II)
aT: shift factor, Ea: activation energy of flow (unit: kJ / mol)
T: temperature (unit: ° C.), n: intercept For the above calculation, commercially available calculation software may be used. As the calculation software, RSI Orchestrator VER. 6.6.3 etc. are mentioned.

  The shift factor (aT) is obtained by moving the logarithmic curve of the melt complex viscosity-frequency at each temperature (T) in the log (Y) = − log (X) axis direction (however, the Y axis and the melt complex). Viscosity, with X axis as the frequency), and the amount of movement at the time of superposition on the melt complex viscosity-frequency curve at 190 ° C. In the superposition, both melt complex viscosity-frequency at each temperature (T) The logarithmic curve shifts the frequency by aT times and the melt complex viscosity by 1 / aT times for each curve. Also, the logarithmic curve is obtained from the three values of 170 ° C, 190 ° C and 210 ° C. The correlation coefficient obtained by multiplication is usually 0.99 or more.

The melt complex viscosity-frequency curve was measured using a viscoelasticity measuring apparatus (for example, a viscoelasticity tester (model RDS-2) manufactured by Rheometric). Specifically, as a sample, a 2 mm thick sheet obtained by pressing the copolymer at 190 ° C. and formed into a disk shape having a diameter of 25 mm × 2 mm was used, and the measurement was performed under the following conditions. . As data processing software, RSI Orchestrator VER. 6.6.3 (manufactured by TI Instruments Japan Co., Ltd.) was used. Moreover, it is preferable to mix | blend a suitable quantity (for example, 1000 ppm) of antioxidant previously with a measurement sample.
Geometry: Parallel plate Measurement temperature: 170 ° C, 190 ° C, 210 ° C
Frequency: 0.5-79.577Hz
Distortion rate: 1.0%
The frequency dependence of the viscosity was measured under the above conditions, and the activation energy of the flow was calculated by deriving the above-mentioned Arrhenius plot. Moreover, it is preferable that the copolymer of this invention has the following characteristics in addition to said requirements (1)-(5).

The copolymer of the present invention is derived from the non-conjugated polyene [C-2] in which two carbon / carbon double bonds that can be polymerized with a metallocene catalyst are present in one molecule. The apparent iodine value (IV) of the structural unit is preferably 0.1 to 3.0 g / 100 g. The apparent iodine value of the component [C-2] is preferably 0.4 to 3.0 g / 100 g, more preferably 0.5 to 3.0 g / 100 g.
By adjusting the iodine value, a copolymer having flow activation energy that satisfies the requirement (5) can be obtained.

It is preferable that the apparent iodine value of the component [C-2] is in the above range because foamability and kneading stability are excellent.
In addition, the apparent iodine number of the said component [C-2] can be calculated | required by < ¹ > H-NMR and < ¹³ > C-NMR.

  Hereinafter, a copolymer obtained from ethylene, propylene, 5-ethylidene-2-norbornene (ENB) and 5-vinyl-2-norbornene (VNB), which are copolymers of the present invention, will be taken as an example, and VNB (molecular weight) A method for obtaining an apparent iodine value derived from 120.2) will be specifically described.

First, as described above, the weight percent of each structural unit contained in the copolymer rubber was determined from ¹³ C-NMR. Subsequently, the integrated value of the peak derived from ENB and the integrated value of the peak derived from the vinyl group of VNB were determined from the ¹ H-NMR spectrometer as follows.

1) [Integral value of peak derived from ENB]; (a), {(total of plural peaks around 4.7 to 5.3 ppm) −2 × (c)}
In addition, since the (a) peak and the (b) peak are detected together in a plurality of peaks near 4.7 to 5.3 ppm, (a) is calculated from the above formula.

2) [Integral value of peak derived from vinyl group of VNB]; (c) Sum of peaks in the vicinity of 5.5 to 6.0 ppm. In the above formulas 1) and 2), (a), (b) and ( c) shows (a), (b) and (c) in the following formulas (X) and (Y), respectively. )

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

Apparent iodine value derived from VNB = [integral value of peak derived from vinyl group of VNB] / [integral value of peak derived from ENB] × [weight% of ENB determined from ¹³ C-NMR spectrometer] × 253.81 / 120.2
The copolymer of the present invention is a copolymer synthesized using a metallocene catalyst as described above. In the present invention, the metallocene catalyst is represented by the following formula (I), (II) or (III). The catalysts represented are preferred.

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

In formula (I), 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 a halo-substituted derivative, a di (hydrocarbyl) amino-substituted derivative, a hydrocarbyloxy-substituted derivative and a di (hydrocarbyl) phosphino-substituted derivative, wherein the number of atoms other than hydrogen atoms of X is 20 or less is there. 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) aminobenzyl. Or M is in an oxidation state of +4, and X is a divalent conjugated diene derivative to form metallacyclopentene with M. 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 (II) will be described.

In formula (II), 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 *, 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 (III) will be described.

In formula (III), 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.
In formula (III), R ″ is a hydrocarbyl group having 1 to 20 carbon atoms or a hydrogen atom.
In the formula (III), M is titanium.
In formula (III), Y represents —O—, —S—, —NR ^* —, —PR ^* —, —NR ₂ ^* , or —PR ₂ ^* .
Wherein (III), Z ^{* _{is, -SiR * 2 -, - CR}} * 2 -, - SiR * 2 SiR * 2 -, - CR * 2 CR * 2 -, - CR * = CR * -, - CR ^* ₂ SiR ^* _2- or -GeR ^* _2- .

Each of 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 ^* includes atoms from 2 to 20, and two R ^{* s} (if R ^* is not a hydrogen atom) that Z ^* optionally may form a ring, and R ^* and Y of Z ^* R ^* in the above may form a ring.

  In formula (III), X is a monovalent anionic ligand having 60 or less atoms, excluding a 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 in the +4 oxidation state, and X ″ is a dianionic selected from the group consisting of a hydrocarbazyl group, an oxyhydrocarbyl group, and a hydrocarbylene dioxy group A ligand, wherein X ″ has atoms of atomic numbers 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 (III), when p is 2 and q and r are 0, M is in the +4 oxidation state, and each X is 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 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 Where M is the +2 oxidation state and X ′ is 1,4-diphenyl-1,3-butadiene or 1,3-pentadiene.
Of the formula (III), a compound represented by the following formula (III ′) is particularly preferable.

In the above formula (III ′), R ′ is a hydrogen atom and 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 —, and each R ^* is independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and of p and q When one 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 , 3-pentadiene, when 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 include linear alkyloxy groups such as oxy group, ethyloxy group, and butyloxy group, and branched alkyloxy groups such as t-butyloxy group and neopentyloxy group. And chlorinated, brominated or fluorinated groups or branched alkyl groups. Examples of the halogenated aryl group include a chlorinated phenyl group and a chlorinated naphthyl group.
In the above formula (III ′), R ″ is preferably a hydrogen atom or methyl, and is 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) silanetitanium (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 of the present invention is carried out by a non-conjugated polyene (component [C-1] and component [C-2]). For example, a double bond at the VNB end can be efficiently incorporated and a long chain branching can be introduced at a high rate. In addition, since the copolymer has a narrow molecular weight distribution and composition distribution, and a copolymer having a very uniform molecular structure can be prepared, The formation of gelled spots 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 copolymer>
When synthesizing the copolymer of the present invention, a metallocene catalyst, preferably a catalyst having the structure exemplified above is used. More specifically, the above catalyst is used as a main catalyst, an organoaluminum compound such as a boron compound and / or a trialkyl compound is used as a cocatalyst, an aliphatic hydrocarbon such as hexane is used as a solvent, and a continuous process using a reactor with a stirrer or A batch method is mentioned.

  Examples of boron compounds include trimethylammonium tetrakis (pentafluorophenyl) borate, di (hydrogenated tallow alkyl) methylammonium tetrakis (pentafluorophenyl) borate, triethylammonium tetrakis (pentafluorophenyl) borate, tripropylammonium tetrakis (penta Fluorophenyl) borate, tri (n-butyl) ammonium tetrakis (pentafluorophenyl) borate, tri (sec-butyl) ammonium tetrakis (pentafluorophenyl) borate, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, N, N-dimethylanilinium n-butyltris (pentafluorophenyl) borate, N, N-dimethylanilinium base Diltris (pentafluorophenyl) borate, N, N-dimethylanilinium tetrakis (4- (t-butyldimethylsilyl) -2,3,5,6-tetrafluorophenyl) borate, N, N-dimethylanilinium tetrakis ( 4- (triisopropylsilyl) -2,3,5,6-tetrafluorophenyl) borate, N, N-dimethylanilinium pentafluorophenoxytris (pentafluorophenyl) borate, N, N-diethylanilinium tetrakis (penta Fluorophenyl) borate, N, N-dimethyl-2,4,6-trimethylanilinium tetrakis (pentafluorophenyl) borate, trimethylammonium tetrakis (2,3,4,6-tetrafluorophenyl) borate, triethylammonium Trakis (2,3,4,6-tetrafluorophenyl) borate, tripropylammonium tetrakis (2,3,4,6-tetrafluorophenyl) borate, N, N-dimethylanilinium tetrakis (2,3,4, 6-tetrafluorophenyl) borate, N, N-diethylanilinium tetrakis (2,3,4,6-tetrafluorophenyl) borate, and N, N-dimethyl-2,4,6-trimethylanilinium tetrakis (2 , 3,4,6-tetrafluorophenyl) borate; dialkylammonium salts such as di- (i-propyl) ammonium tetrakis (pentafluorophenyl) borate, tri (n-butyl) ammonium tetrakis (2,3,4, 6-tetrafluorophenyl) borate, dimethyl (t-butyl) E) ammonium tetrakis (2,3,4,6-tetrafluorophenyl) borate, and dicyclohexylammonium tetrakis (pentafluorophenyl) borate; trisubstituted phosphonium salts such as triphenylphosphonium tetrakis (pentafluorophenyl) borate, Tri (o-tolyl) phosphonium tetrakis (pentafluorophenyl) borate and tri (2,6-dimethylphenyl) phosphonium tetrakis (pentafluorophenyl) borate; disubstituted oxonium salts such as diphenyloxonium tetrakis (pentafluoro Phenyl) borate, di- (o-tolyl) oxonium tetrakis (pentafluorophenyl) borate, and di (2,6-dimethylphenyl) oxonium tetrakis (Pentafluorophenyl) borate; disubstituted sulfonium salts such as diphenylsulfonium tetrakis (pentafluorophenyl) borate, di (o-tolyl) sulfonium tetrakis (pentafluorophenyl) borate, and bis (2,6-dimethylphenyl) ) Sulfonium tetrakis (pentafluorophenyl) borate and the like.

  Examples of the organoaluminum compound include triisobutylaluminum (hereinafter also referred to as “TIBA”). The reaction temperature can be raised to 100 ° C. because the catalyst is not deactivated even at high temperatures. The polymerization pressure is in the range of 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. Further, in the copolymerization, a molecular weight regulator such as hydrogen can be used.

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

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

  The molar (feed) ratio ([A] / [C-1]) of ethylene [A] and the non-conjugated polyene [C-1] is 70/30 to 99/1, preferably 80/20 to 98/2. It is.

  The molar (feed) ratio ([A] / [C-2]) of ethylene [A] and the non-conjugated polyene [C-2] is 70/30 to 99.9 / 0.1, preferably 80/20. ~ 99.5 / 0.5.

  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.

  In the copolymer of the present invention thus obtained, the structural unit derived from the α-olefin [B] having 3 to 20 carbon atoms is 10 to 50 mol% in 100 mol% of all structural units, Preferably it is 25-45 mol%. Further, among the carbon / carbon double bonds, the mol% of the structural unit derived from the non-conjugated polyene [C-1] in which only one carbon / carbon double bond polymerizable with a metallocene catalyst is present in one molecule and Among carbon / carbon double bonds, the total of mol% of structural units derived from non-conjugated polyene [C-2] in which two carbon / carbon double bonds that can be polymerized with a metallocene catalyst are present in one molecule is 1. It is 0.0-6.0 mol%, More preferably, it is 1.0-5.0 mol%. Among the carbon-carbon double bonds, the carbon-carbon double bond polymerizable by the metallocene catalyst is only one mol-% of the structural unit derived from the non-conjugated polyene [C-1], and carbon Ratio of carbon-carbon double bonds polymerizable by a metallocene catalyst among the carbon double bonds to the mol% of structural units derived from non-conjugated polyene [C-2] existing in one molecule ([C -1] / [C-2]) is 75/25 to 99.5 / 0.5, preferably 78/22 to 97/3.

  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.

<Rubber composition>
The rubber composition of the present invention contains the copolymer [I], a vinyl chloride resin and / or a flame retardant [II], a softener [III], and a foaming agent, and [I], [II] and The content of [III] satisfies the relational expression of formula (ii) and contains 5 to 50 parts by weight, preferably 8 to 40 parts by weight of the foaming agent with respect to 100 parts by weight of [I].
(Vinyl chloride resin and / or flame retardant [II]) / (copolymer [I] + softener [III]) ≧ 1.50 (ii)
Preferably,
It is (vinyl chloride resin and / or flame retardant [II]) / (copolymer [I] + softener [III]) ≧ 1.7.
The upper limit of formula (ii) is preferably 2.8 or less, more preferably 2.5 or less.

  Within the above range, good kneading workability is exhibited, and the vinyl chloride resin and / or the flame retardant functions effectively to exhibit excellent flame retardancy.

  Moreover, the rubber composition of the present invention may contain a polyolefin resin. When the polyolefin resin is contained in the rubber composition of the present invention, it is preferable that when the composition of the present invention is foamed, the polyolefin resin melts to obtain a crosslinked foam having a large expansion ratio.

  Examples of the polyolefin resin include polyethylene, polypropylene, polybutene, and an ethylene-α olefin copolymer. Among them, polyethylene and an ethylene-α olefin copolymer are preferable. When the polyolefin resin is contained in the rubber composition of the present invention, it is preferable to contain 5 to 60 parts by weight of the polyolefin resin with respect to 100 parts by weight of the copolymer. As the polyolefin resin, for example, commercially available Mirason 27 (polyethylene), Tuffmer (ethylene-butene copolymer), or the like can be used.

  The rubber composition of the present invention may contain components other than the copolymer, the foaming agent, and the polyolefin resin.

  Examples of other components include foaming aids, vulcanizing agents, vulcanization accelerators, vulcanizing aids, reinforcing agents, inorganic fillers, softeners, anti-aging agents (stabilizers), processing aids, activators. And various additives such as a hygroscopic agent. Moreover, rubber components other than the copolymer of this invention can also be mix | blended. The content of the copolymer (I) in the entire rubber composition of the present invention is preferably 20% by weight or more.

  The rubber composition of the present invention can be produced by kneading the copolymer of the present invention and other components at a predetermined temperature using a conventionally known kneader such as a mixer, a kneader, or a roll. . A specific example of the method for producing the rubber composition of the present invention is obtained by alloying the copolymer and other components with an extruder in the presence of a solvent. Since the copolymer of the present invention is excellent in kneadability, the rubber composition can be produced satisfactorily.

[Vinyl chloride resin]
Examples of the vinyl chloride resin include a vinyl chloride resin, a copolymer of vinyl chloride and a polymerizable monomer copolymerizable with the vinyl chloride, a graft polymer obtained by graft polymerization of vinyl chloride on the polymer, and post-chlorinated products thereof. Etc., and may be used alone or in combination of two or more.

  The polymerizable monomer is not particularly limited as long as it is copolymerizable with vinyl chloride. Examples thereof include α-olefins such as ethylene, propylene and butylene; vinyl esters such as vinyl acetate and vinyl propionate; butyl Vinyl ethers such as vinyl ether and cetyl vinyl ether; (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate; aromatic vinyls such as styrene and α-methylstyrene; halogens such as vinylidene chloride and vinyl fluoride Vinyl halides; N-substituted maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide;

  As the copolymer, an ethylene-vinyl chloride copolymer is preferable, and the composition ratio of the ethylene and vinyl chloride is 1:99 because the flame retardant property and heat resistance are lowered when the ethylene content is increased. -10: 90 is preferable, More preferably, it is 4: 96-8: 92.

  The polymer for graft polymerization of vinyl chloride is not particularly limited as long as vinyl chloride can be graft polymerized, and examples thereof include ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-carbon monoxide copolymer. Polymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, ethylene-ethyl acrylate-carbon monoxide copolymer, acrylonitrile-butadiene copolymer, polyurethane, chlorinated polyethylene, chlorinated polypropylene, etc. .

  As the polymer for graft polymerization of vinyl chloride, an ethylene-vinyl acetate copolymer is preferable. When the vinyl chloride content in the polymer increases, impact resistance and moldability deteriorate, and ethylene and vinyl acetate content. Since the flame retardancy and the heat resistance are reduced when the amount of A is increased, the weight ratio of ethylene, vinyl acetate and vinyl chloride (ethylene: vinyl acetate: vinyl chloride) is preferably from 2: 1: 97 to 25:20:55, and more Preferably they are 5: 2: 93-10: 6: 84.

  When the chlorine content of the vinyl chloride resin decreases, flame retardancy and heat resistance decrease, and when it increases, the moldability decreases. Therefore, it is used in the range of 50 to 73% by weight, preferably 56 to 71% by weight. is there.

  The compounding quantity of vinyl chloride-type resin is 20-100 weight part with respect to 100 weight part of copolymers [I], Preferably it is 30-80 weight part. When the blending amount is within the above range, the obtained crosslinked foam is excellent in flame retardancy (self-digestibility) and exhibits good moldability.

〔Flame retardants〕
Flame retardancy includes triphenyl phosphate, tricresyl phosphate, resorcinol bis (diphenyl) phosphate, aromatic phosphate ester, aromatic condensed phosphate ester, ammonium polyphosphate, etc. Inorganic flame retardants such as aluminum, magnesium hydroxide, zinc borate, molybdenum compound, zinc stannate, silicone compound, and phosphazene compound are used.

  The compounding quantity of a flame retardant is 80-260 weight part with respect to 100 weight part of copolymers [I], Preferably it is 100-250 weight part. When the blending amount is within the above range, the obtained crosslinked foam is excellent in flame retardancy and exhibits good moldability.

[Softener]
The softening agent can be appropriately selected depending on the application, and can be used alone or in combination of two or more. Specific examples of the softener include process oil (for example, “Diana Process Oil PS-430” (trade name; manufactured by Idemitsu Kosan Co., Ltd.)), lubricating oil, paraffin oil, liquid paraffin, petroleum asphalt, petroleum jelly and the like. Petroleum softeners; 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; beeswax, carnauba wax, and lanolin Waxes such as ricinoleic acid, palmitic acid, stearic acid, barium stearate, calcium stearate, and zinc laurate or salts thereof; naphthenic acid, pine oil, and rosin or derivatives thereof; terpene resins, petroleum resins, Synthesis of atactic polypropylene and coumarone indene resin Polymeric substances; ester softeners such as dioctyl phthalate, dioctyl adipate, and dioctyl sebacate; other microcrystalline wax, liquid polybutadiene, modified liquid polybutadiene, liquid thiocol, hydrocarbon synthetic lubricating oil, tall oil, and sub ( Factis). Of these, petroleum softeners are preferable, and process oil is particularly preferable.

  The blending amount of the softening agent is 5 to 150 parts by weight, preferably 10 to 100 parts by weight, and more preferably 10 to 90 parts by weight with respect to 100 parts by weight of the copolymer [I]. When the blending amount is within the above range, good moldability is exhibited, and the resulting crosslinked foam is excellent in flexibility.

[Foaming agent]
Examples of the foaming agent that the rubber composition of the present invention may contain include inorganic foaming agents such as sodium bicarbonate and sodium carbonate; N, N′-dinitrosopentamethylenetetramine, N, N′-dinitrosotephthale Nitroso compounds such as amides; azo compounds such as azodicarbonamide and azobisisobutyronitrile; hydrazide compounds such as benzenesulfonyl hydrazide and 4,4′-oxybis (benzenesulfonylhydrazide); calcium azide and 4,4′-diphenyl Organic foaming agents such as azide compounds such as disulfonyl azide.

The blending amount of the foaming agent is 5 to 50 parts by weight, preferably 7 to 40 parts by weight with respect to 100 parts by weight of the copolymer [I]. As the foaming agent, for example, commercially available VINYHALL AC # LQ (trade name; Eiwa Kasei Kogyo Co., Ltd., Azodicarbonamide (abbreviation ADCA)), Neocerbon N # 1000SW (trade name; Eiwa Kasei Kogyo Co., Ltd. 4,4 ′) -Oxybis (benzenesulfonylhydrazide) (abbreviation OBSH)), Cellular D (trade name; Eiwa Chemical Industry Co., Ltd. N, N'-dinitrosopentamethylenetetramine (abbreviation DPT))
Etc. can be used.

[Foaming aid]
The rubber composition of the present invention may contain a foaming aid together with a foaming agent, if necessary. The foaming assistant exhibits actions such as a reduction in the decomposition temperature of the foaming agent, acceleration of decomposition, and uniformization of bubbles. Examples of such foaming aids include organic acids such as salicylic acid, phthalic acid, stearic acid, oxalic acid, and citric acid, salts thereof, urea, and derivatives thereof.

  The blending amount of the foaming aid is 0.1 to 5 parts by weight, preferably 0.5 to 4 parts by weight, based on 100 parts by weight of the copolymer. As the foaming aid, for example, commercially available cell paste K5 (trade name; Yawa Chemical Industry Co., Ltd. urea), FE-507 (trade name; Eiwa Chemical Industries, Ltd. baking soda) and the like can be used.

(Vulcanizing agent (crosslinking agent))
As the vulcanizing agent (crosslinking agent), a sulfur compound, an organic peroxide, a phenol resin, an oxime compound, or the like can be used.

  Examples of sulfur compounds include sulfur, sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide, selenium dithiocarbamate, and the like. The sulfur compound is preferably sulfur or tetramethylthiuram disulfide, and is usually 0.3 to 10 parts by weight, preferably 0.5 to 5.0 parts by weight, more preferably 100 parts by weight of the copolymer. 0.7 to 4.0 parts by weight can be blended. When the blending amount is within the above range, there is no bloom on the surface of the obtained crosslinked foamed material, which is preferable since 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, 2, Examples include 5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, di-t-butyl peroxide, di-t-butylperoxy-3,3,5-trimethylcyclohexane, t-dibutyl hydroperoxide, etc. it can. Of these, dicumyl peroxide, di-t-butyl peroxide, and di-t-butylperoxy-3,3,5-trimethylcyclohexane are preferable.

  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 0.015 mol with respect to 100 g of the copolymer. is there. When the amount of the organic peroxide is within the above range, it is preferable because excellent crosslinking characteristics are exhibited without blooming on the surface of the resulting crosslinked foam.

[Vulcanization accelerator]
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) benzothiazole (for example, “ Noxeller MDB-P "(trade name; manufactured by Sanshin Chemical Industry Co., Ltd.), 2- (2,4-dinitrophenyl) mercaptobenzothiazole, 2- (2,6-diethyl-4-morpholinothio) benzo Thiazoles such as thiazole and dibenzothiazyl disulfide; guanidines such as diphenylguanidine, triphenylguanidine and diorthotolylguanidine; acetaldehyde-aniline condensate, butyraldehyde-aniline condensate, aldehyde amine; 2-mercaptoimidazoline, etc. Imidazoline; diethylthiourea Thiourea series such as dibutylthiourea; Thiuram series such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; Zinc dimethyldithiocarbamate, Zinc diethyldithiocarbamate, Zinc dibutyldithiocarbamate (for example, “Suncellar PZ” (trade name; Kogyo Co., Ltd.), "Sunseller BZ" (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.), dithioates such as tellurium diethyldithiocarbamate; ethylenethiourea (for example, "Sunseller BUR" (trade name; three) Shin Chemical Industry Co., Ltd.), "Sunseller 22-C" (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.), thiourea type such as N, N'-diethylthiourea, xanthate type such as zinc dibutylxatogenate Other zinc white (for example, “META-Z102” ( Product name; manufactured by Inoue lime Industry Co., Ltd.), and the zinc oxide), or the like, such as.

  The amount of these vulcanization accelerators is 0.1 to 20 parts by weight, preferably 0.2 to 15 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the copolymer. It is. When the blending amount of the vulcanization accelerator is within the above range, it is preferable because the resulting crosslinked foam does not bloom on the surface and exhibits excellent crosslinking characteristics.

[Vulcanization aid]
Vulcanization aids can be appropriately selected depending on the application, and can be used alone or in combination of two or more. Specific examples of the vulcanization aid include magnesium oxide and zinc white (for example, zinc oxide such as “META-Z102” (trade name; manufactured by Inoue Lime Industry Co., Ltd.)). The compounding quantity is 1-20 weight part normally with respect to 100 weight part of copolymers. As vulcanization aids, quinone dioximes such as p-quinonedioxime; acrylics such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate; allyls such as diallyl phthalate and triallyl isocyanurate; other maleimides; Examples include divinylbenzene.

[Reinforcing agent and inorganic filler]
In the rubber composition of the present invention, a reinforcing agent may be blended in order to improve mechanical properties such as tensile strength, tear strength, and abrasion resistance of the rubber composition. As a reinforcing agent, specifically, “Asahi # 55G” and “Asahi # 50HG” (trade name; manufactured by Asahi Carbon Co., Ltd.), “Seast (trade name)” series: SRF, GPF, FEF, Carbon black (manufactured by Tokai Carbon Co., Ltd.) such as MAF, HAF, ISAF, SAF, FT, MT, etc., those carbon black surface-treated with a silane coupling agent, silica, activated calcium carbonate, fine talc, fine powder silica An acid or the like can be used. Of these, carbon black of “Asahi # 55G”, “Asahi # 50HG”, “Seast HAF” is preferable. As the inorganic filler, light calcium carbonate, heavy calcium carbonate, talc, clay, or the like can be used. Of these, heavy calcium carbonate is preferred. As heavy calcium carbonate, commercially available “Whiteon SB” (trade name; Shiraishi Calcium Co., Ltd.) and the like can be used.

  The compounding amount of the reinforcing agent and / or inorganic filler is usually 30 to 200 parts by weight, preferably 50 to 180 parts by weight, and more preferably 70 to 160 parts by weight with respect to 100 parts by weight of the copolymer. A blending amount within the above range is preferable because the rubber composition is excellent in kneading processability, mechanical properties (for example, strength, flexibility, etc.) of the resulting rubber molded article and compression set.

[Anti-aging agent (stabilizer)]
The rubber composition of the present invention is the same as a normal rubber composition in that the product life can be extended by using an anti-aging agent, and a conventionally known anti-aging agent such as an amine-based anti-aging agent is used. An inhibitor, a phenol-based anti-aging agent, a sulfur-based anti-aging agent and the like can be used.

  Specific examples of the antioxidant include aromatic secondary amine-based antioxidants such as phenylbutylamine, N, N-di-2-naphthyl-pphenylenediamine, dibutylhydroxytoluene, tetrakis [methylene (3,5 -Di-tert-butyl-4-hydroxy) hydrocinnamate] phenolic antioxidants such as methane; bis [2-methyl-4- (3-n-alkylthiopropionyloxy) -5-tert-butylphenyl] sulfide Thioether-based anti-aging agents such as dibutyl dithiocarbamate nickel dithiocarbamate-based anti-aging agents; 2-mercaptobenzoylimidazole, zinc salt of 2-mercaptobenzimidazole, dilauryl thiodipropionate, distearyl thiodipropionate And sulfur-based anti-aging agents such as

  These anti-aging agents can be used alone or in combination of two or more, and the blending amount of such anti-aging agents is usually 0.3 to 10 parts by weight with respect to 100 parts by weight of the rubber composition. , Preferably 0.5 to 7.0 parts by weight, more preferably 0.7 to 5.0 parts by weight. When the blending amount of the anti-aging agent is within the above range, there is no bloom on the surface of the rubber composition to be obtained, and further, vulcanization inhibition does not occur.

[Processing aid]
As processing aids, those generally blended into rubber as processing aids can be widely used. Specific examples include ricinoleic acid, stearic acid, palmitic acid, lauric acid, barium stearate, zinc stearate, calcium stearate or esters. Of these, stearic acid is preferred. The processing aid can be appropriately blended in an amount of 10 parts by weight or less, preferably 8.0 parts by weight or less, more preferably 5.0 parts by weight or less, relative to 100 parts by weight of the copolymer. When the blending amount of the processing aid is within the above range, there is no bloom on the surface of the rubber composition to be obtained, and further, vulcanization inhibition does not occur.

[Activator]
In the present invention, the activator used as necessary can be appropriately selected depending on the application, and can be used alone or in combination of two or more. Specific examples of the activator include di-n-butylamine, dicyclohexylamine, monoelaanolamine, “Acting B” (trade name; manufactured by Yoshitake Pharmaceutical Co., Ltd.), and “Acching SL” (trade name; Yoshitsugu Pharmaceutical Co., Ltd.). Amines such as diethylene glycol, polyethylene glycol (for example, “PEG # 4000” (manufactured by Lion Corporation)), lecithin, triarylate melitrate, zinc compounds of aliphatic and aromatic carboxylic acids (for example, “Struktol activator”). 73 "," Struktol IB 531 "and" Struktol FA541 "(trade name; manufactured by Schill &Seilacher)); zinc peroxide preparations such as" ZEONET ZP "(trade name; manufactured by Nippon Zeon Co., Ltd.) ; Kutadecyl Trime Le ammonium bromide, synthetic hydrotalcite, special quaternary ammonium compounds (e.g., "Arquad 2HF" (trade name, manufactured by Lion Akzo Co., Ltd.)), and the like. Among these, polyethylene glycol (for example, “PEG # 4000” (manufactured by Lion Corporation)) and “Arcade 2HF” are preferable. The compounding quantity of an activator is 0.2-10 weight part with respect to 100 weight part of copolymers, Preferably it is 0.3-5 weight part, More preferably, it is 0.5-4 weight part.

[Hygroscopic agent]
In the present invention, the hygroscopic agent used as necessary can be appropriately selected depending on the application, and can be used alone or in combination of two or more. Specific examples of the activator 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 0.5 to 15 parts by weight, preferably 1.0 to 12 parts by weight, and more preferably 1.0 to 10 parts by weight with respect to 100 parts by weight of the copolymer.
In addition, the additive normally used for a rubber composition can be arbitrarily used within the range which does not impair the objective of this invention.

<Crosslinked rubber>
The crosslinked rubber of the present invention is obtained by crosslinking the rubber composition. Examples of the method for crosslinking the rubber composition include the following two methods. As a first method, (i) a rubber composition blended with the vulcanizing agent, usually 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, LCM (hot molten salt bath), etc. are heated into a desired shape, such as a heating bath, and the molded product is introduced into the vulcanizing tank at the same time as the pre-molding. The second method is (ii) a method in which the rubber composition of the present invention is preformed by the above molding method and irradiated with an electron beam.

In the case of (i), the vulcanizing agent is used, and if necessary, the vulcanization accelerator and / or the vulcanization auxiliary can be used in combination. Moreover, as temperature at the time of heating, it is generally 140-300 degreeC, Preferably it is 150-270 degreeC, More preferably, it is 150-250 degreeC, 0.5-30 minutes, Preferably it is 0.5-20 minutes, More preferably, it is desirable to heat for 0.5 to 15 minutes.
When molding and vulcanizing the rubber composition, a mold may be used or a mold may not be used. When a mold is not used, the rubber composition is usually molded and vulcanized continuously.

  (Ii) When the rubber composition of the present invention is preformed by the above molding method and irradiated with an electron beam, an electron beam having an energy of 0.1 to 10 MeV is absorbed into the preformed rubber composition. Of 0.5 to 35 Mrad, preferably 0.5 to 20 Mrad, more preferably 1 to 10 Mrad.

<Crosslinked foam>
The crosslinked foam of the present invention is a crosslinked foam obtained by crosslinking and foaming the rubber composition, and has a specific gravity of 0.03 to 0.3 and a surface roughness of the foam of 30 μm or less. It is characterized by that.

  In order to cross-link and foam the rubber composition, a rubber composition containing a foaming agent is usually used for crosslinking and foaming. As an example of cross-linked foam molding, a rubber composition is extruded using a 60φ mm extruder equipped with a tubular die (inner diameter / outer diameter 4/11 Φmm) under conditions of a die temperature of 80 ° C. and a cylinder temperature of 60 ° C. A molded sponge is obtained, and this molded body is introduced into a vulcanizing tank at the same time as molding and heated at a temperature of 180 ° C. for 10 minutes to perform crosslinking and foaming to obtain a tubular sponge. Is mentioned.

  Since the cross-linked foam of the present invention has a high foaming ratio and a low specific gravity and exhibits good surface smoothness, the coated sponge material, the highly foamed sponge material, the heat-insulating sponge, etc. made of the cross-linked foam of the present invention are lightweight and Flexible and preferable.

  The cross-linked foam of the present invention is suitably used for, for example, piping, pipe and tube covering sponges, automobile seal sponges, and the like.

EXAMPLES Next, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited by these.
Each physical property of the obtained copolymer was measured according to the following.

[Mole amount of structural unit derived from α-olefin [B] having 3 to 20 carbon atoms, carbon / carbon double bond polymerizable with metallocene catalyst among carbon / carbon double bonds is 1 Mol% of structural units derived from only one non-conjugated polyene [C-1], and two carbon / carbon double bonds that can be polymerized with a metallocene catalyst among carbon / carbon double bonds in one molecule Mol% of structural units derived from non-conjugated polyene [C-2] present]
^It calculated | required by the intensity | strength measurement by a < ¹³ > C-NMR spectrum meter.

[Apparent iodine value of structural unit derived from non-conjugated polyene [C-2] in which two carbon / carbon double bonds polymerizable with a metallocene catalyst are present in one molecule. IV)]
^It calculated | required with the < ¹ > H-NMR spectrum meter and the < ¹³ > C-NMR spectrum meter.

[Mooney viscosity [ML _{1 + 4} (100 ° C)]]
Mooney viscosity [ML _{1 + 4} (100 ° C.)] was measured according to JIS K6300 using a Mooney viscometer (SMV202 type, manufactured by Shimadzu Corporation).

[Flow activation energy (Ea)]
Temperature-time superposition of the melt complex viscosity-frequency curve (unit of melt complex viscosity; Pa / sec, unit of frequency; Hz) of the copolymer at temperatures of 170 ° C. and 210 ° C. (T, unit; ° C.) For each temperature (T) obtained when superimposed on the melt complex viscosity-frequency curve of the copolymer at 190 ° C. for each melt complex viscosity-frequency curve at each temperature (T) based on the principle of From the shift factor (aT), a first-order approximate expression (formula (I) below) of [ln (aT)] and [1 / (T + 273.16)] was calculated by the method of least squares. Next, Ea was determined from the slope m of the linear equation and the following equation (II).
ln (aT) = m (1 / (T + 273.16)) + n (I)
Ea = [0.008314 × m] (II)
aT: shift factor, Ea: activation energy of flow (unit: kJ / mol)
T: temperature (unit: ° C.), n: intercept The above calculation was performed using commercially available calculation software (RSI Orchestrator VER. 6.6.3, manufactured by T.A. Instruments Japan Co., Ltd.). .

  The shift factor (aT) is obtained by moving the logarithmic curve of the melt complex viscosity-frequency at each temperature (T) in the log (Y) = − log (X) axis direction (however, the Y axis and the melt complex). Viscosity, with X axis as the frequency), and the amount of movement at the time of superposition on the melt complex viscosity-frequency curve at 190 ° C. In the superposition, both melt complex viscosity-frequency at each temperature (T) The logarithmic curve shifts the frequency by aT times and the melt complex viscosity by 1 / aT times for each curve. Also, the logarithmic curve is obtained from the three values of 170 ° C, 190 ° C and 210 ° C. The correlation coefficient when obtained by multiplication is usually 0.99 or more.

The melt complex viscosity-frequency curve was measured using a viscoelasticity measuring device (Rheometric Viscoelasticity Tester (Model RDS-2)). Specifically, as a sample, a 2 mm thick sheet obtained by pressing the copolymer at 190 ° C. and formed into a disk shape having a diameter of 25 mm × 2 mm was used, and the measurement was performed under the following conditions. . As data processing software, RSI Orchestrator VER. 6.6.3 (manufactured by TI Instruments Japan Co., Ltd.) was used. Moreover, it is preferable to mix | blend an appropriate quantity (for example, 1000 ppm) of antioxidant previously with a measurement sample.
Geometry: Parallel plate Measurement temperature: 170 ° C, 190 ° C, 210 ° C
Frequency: 0.5-79.577Hz
Distortion rate: 1.0%
The frequency dependence of the viscosity was measured under the above conditions, and the activation energy of the flow was calculated by deriving the above-mentioned Arrhenius plot.
〔Flame retardance〕
An HBF flame retardant test based on the UL94 standard was performed to evaluate whether or not the HF-1 grade was met.

[EPDM-1]
Using a 300 L polymerization vessel equipped with a stirring blade, component [A]: ethylene, component [B]: propylene, component [C-1]: 5-ethylidene-2-norbornene (ENB) and component [C-2]: A quaternary copolymer composed of 5-vinyl-2-norbornene (VNB) was subjected to a polymerization reaction at 95 ° C.

As a polymerization solvent, hexane (feed amount 41 kg / h) was used, ethylene feed amount 5.3 kg / h, propylene feed amount 5.6 kg / h, ENB feed amount 900 g / h, VNB feed amount 90 g / h. h was continuously fed to the polymerization vessel. (T-Butylamido) -dimethyl (η ⁵ -2-methyl-s-indacene-1-yl) is a catalyst having a structure represented by the above formula (VIII) as a main catalyst while maintaining the polymerization pressure at 1.5 MPa. ) Using silane titanium (II) 1,3-pentadiene, it was continuously fed to the polymerization vessel so as to be 0.05 mmol / h. Further, (C ₆ H ₅ ) ₃ CB (C ₆ F ₅ ) ₄ is 0.25 mmol / h as a cocatalyst, and triisobutylaluminum (hereinafter also referred to as “TIBA”) is ₁₅ mmol / h as an organoaluminum compound. Each was continuously fed to the polymerization vessel.

  In this way, a polymerization liquid containing 16.6% by weight of a copolymer composed of ethylene, propylene, ENB and VNB was obtained. A small amount of methanol was added to the polymerization solution extracted from the lower part of the polymerization vessel to stop the polymerization reaction. The polymer was separated from the solvent by a steam stripping treatment, and then dried under reduced pressure at 80 ° C. overnight. The physical properties of the obtained copolymer are shown in Table 1.

[EPDM-2]
The synthesis was performed under the same conditions as in Example 1 except that the feed amounts of ethylene, propylene, ENB and VNB were changed. The physical properties of the obtained copolymer are shown in Table 1.

[EPDM-3]
The synthesis was performed under the same conditions as in Example 1 except that the feed amounts of ethylene, propylene, ENB and VNB were changed. The physical properties of the obtained copolymer are shown in Table 1.

[EPDM-4]
The synthesis was performed under the same conditions as in Example 1 except that the feed amounts of ethylene, propylene, ENB and VNB were changed. The physical properties of the obtained copolymer are shown in Table 1.

[EPDM-5]
The synthesis was performed under the same conditions as in Example 1 except that the feed amounts of ethylene, propylene, ENB and VNB were changed. The physical properties of the obtained copolymer are shown in Table 1.

[EPDM-6]
The synthesis was performed under the same conditions as in Example 1 except that the feed amounts of ethylene, propylene, ENB and VNB were changed. The physical properties of the obtained copolymer are shown in Table 1.

[EPDM-7]
Ethylene / propylene / 5-ethylidene-2-norbornene terpolymer [trade name: Esprene 505A (trademark), manufactured by Sumitomo Chemical Co., Ltd., ethylene content: 54 wt%, diene content: 9.5 wt%, ML1 + 4 (100 ° C.) 47, flow activation energy 32.6 KJ / mol]

[Reference Example: NBR]
Acrylonitrile butadiene rubber (NBR) [trade name: NIPOL3350 (trademark), manufactured by Nippon Zeon Co., Ltd., bound acrylonitrile amount 33.0%, ML1 + 4 (100 ° C.) 50]

Hereinafter, the measuring method of each physical property of a rubber composition is shown.
[Minimum viscosity (Vm) and scorch time (t5)]
The physical property test of the unvulcanized rubber was performed according to JIS K6300. Specifically, using a Mooney viscometer (SMV202 type manufactured by Shimadzu Corporation), the change in Mooney viscosity is measured at 125 ° C., the minimum viscosity (Vm) is obtained from the start of measurement, and further 5 from the minimum viscosity Vm. The time until the point was raised was determined and this was taken as the scorch time (t5, min).

〔specific gravity〕
The upper part of the tubular sponge was punched with a 20 mm × 20 mm test piece, and the surface dirt was wiped off with alcohol. This test piece was attached to an automatic hydrometer (manufactured by Toyo Seiki Seisakusho: M-1 type) in an atmosphere of 25 ° C., and the specific gravity was measured from the difference in mass between air and pure water.

[Evaluation of surface smoothness]
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.

[Ozone resistance]
Dynamic ozone resistance of vulcanized rubber sheet with a thickness of 2 mm under the conditions of ozone concentration 50 pphm, measurement temperature 40 ° C., elongation rate (dynamic elongation) 0 → 25%, frequency 1 Hz in accordance with JISK6259 (2001) An evaluation test was conducted, and the occurrence of cracks 72 hours after the start of the test was observed and evaluated. The occurrence of cracks was recorded by [1] number of cracks and [2] size and depth of cracks determined by the following evaluation criteria, and combining [1] and [2]. “NC” in the table indicates that no crack was confirmed.
[1] Number of cracks A): Few cracks, B): Many cracks, C): Myriad cracks [2] Crack size and depth 1): What can not be seen with the naked eye but can be confirmed with a 10x magnifier 2): What two people can do with the naked eye 3): Deep crack and relatively large (less than 1 mm)
4): Deep and large cracks (1 mm or more and less than 3 mm)
5): Those that are likely to cause cracks or cuts of 3 mm or more

〔Flame retardance〕
An HBF flame retardant test based on the UL94 standard was performed to evaluate whether or not the HF-1 grade was met.

[Reference example]
The rubber composition and sponge (cross-linked foam) described in Reference Examples were obtained by the following production method.
First, the rubber composition before vulcanization and foaming in the rubber composition of the reference example is MIXTRON BB MIXER (Kobe Steel Co., Ltd., BB-4 type, volume 2.95 L, rotor 4WH), NBR [ Product name: NIPOL 3350 (trademark), manufactured by Nippon Zeon Co., Ltd., bound acrylonitrile amount 33.0%, ML1 + 4 (100 ° C.) 50] 100 parts by weight as a vinyl chloride resin “Luron 810 (trade name; Tosoh Corporation) Co., Ltd.) 40 parts by weight, "META-Z102" (trade name; manufactured by Inoue Lime Industry Co., Ltd.) as a vulcanization aid, 5 parts by weight of stearic acid as a processing aid, and "Heidi" as a flame retardant 50 parts by weight of “Light H42M” (trade name; manufactured by Showa Denko KK) and 10 parts by weight of “TCP” (trade name; manufactured by Daihachi Chemical Industry Co., Ltd.) 10 parts by weight of “antimony” (trade name; manufactured by Nippon Seiko Co., Ltd.), 30 parts by weight of “Asahi # 50G” (trade name; manufactured by Asahi Carbon Co., Ltd.) as a reinforcing agent, and “DOP” (trade name) as a softening agent 15 parts by weight of Daihachi Chemical Industry Co., Ltd., 1 part by weight of “Kaoh Wax EB” (trade name; manufactured by Kao Corporation) as a lubricant, and “Rheodor SP-S10V8” (trade name; manufactured by Kao Corporation) 1 part by weight was kneaded.
The kneading conditions were a rotor rotation speed of 50 rpm, a floating weight pressure of 3 kg / cm ² , a kneading time of 5 minutes, and a kneading discharge temperature of 126 ° C.

  Next, after confirming that the temperature of the blend became 40 ° C., “Sunseller M” (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.) was used as a vulcanization accelerator to the blend using a 14-inch roll. 0.5 parts by weight, "Sunseller CM" (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.) as a vulcanization accelerator, 1.0 parts by weight, "Sunseller TT" (trade name; Sanshin Chemical) as a vulcanization accelerator 0.5 parts by weight of Kogyo Co., Ltd. and 1.0 part by weight of sulfur as a vulcanizing agent were kneaded. The kneading conditions were as follows: roll temperature: front roll / rear roll = 65 ° C./50° C., roll rotation speed: front roll / rear roll = 13 rpm / 11.5 rpm, roll gap of 5 mm, and kneading time 8 minutes. -1 was prepared. This compound-1 was vulcanized at 160 ° C. for 10 minutes using a press molding machine to prepare a rubber sheet having a thickness of 2 mm. About the obtained vulcanizate, the ozone-proof test was done by the said method. The results are shown in Table 2. In addition, 31.25 parts by weight of “Neothrene HM804A” (trade name: Eiwa Kasei Kogyo Co., Ltd.) as a foaming agent and “Cell Paste K5” (trade name: Eiwa Kasei Kogyo Co., Ltd.) as a foaming aid are added to this formulation-1. ) Was mixed with 2.0 parts by weight and “VESTA 18” (trade name; Inoue Lime Industry Co., Ltd.) as a hygroscopic agent. The kneading conditions are as follows: roll temperature is front roll / rear roll = 80 ° C./80° C., roll peripheral speed is front roll / rear roll = 13 rpm / 11.5 rpm, roll gap is 5 mm, and kneading time is 15 minutes. Product-2 was prepared. This rubber compound-2 was extruded under the conditions of a die temperature of 80 ° C. and a cylinder temperature of 60 ° C. using a 60 φmm extruder attached to a tube die (inner diameter / outer diameter 4/11 Φmm), and formed into a tube flat plate shape. This molded body was introduced into a vulcanizing tank simultaneously with molding and heated at a temperature of 180 ° C. for 10 minutes to carry out a crosslinking reaction and a foaming reaction to obtain a tubular sponge. Table 2 shows the physical property values of the obtained tubular sponge.

[Example 1]
The rubber composition and sponge (crosslinked foam) of the present invention were obtained by the following production method.
First, the rubber composition before vulcanization and foaming in the rubber composition of the present invention was mixed using MIXTRON BB MIXER (Kobe Steel Works, BB-4 type, volume 2.95 L, rotor 4WH). As a vinyl chloride resin, 50 parts by weight of “Luron 810 (trade name; Tosoh Corporation) as a vulcanization aid is used for 100 parts by weight of the blend (ethylene / propylene / non-conjugated polyene copolymer of EPDM-1). 8 parts by weight of “META-Z102” (trade name; manufactured by Inoue Lime Industry Co., Ltd.), 2 parts by weight of stearic acid as a processing aid, and “PEG # 4000” (trade name; polyethylene glycol, Lion Corporation) 1 part by weight, aluminum hydroxide “Hijilite H42M” (trade name; manufactured by Showa Denko KK) as a flame retardant and 160 parts by weight -Based flame retardant “TCP” (trade name; manufactured by Daihachi Chemical Industry Co., Ltd.) 10 parts by weight, “Asahi # 50G” (trade name; manufactured by Asahi Carbon Co., Ltd.) as a reinforcing agent, 20 parts by weight of Diana Process Oil PS-430 (trade name; manufactured by Idemitsu Kosan Co., Ltd.), 1 part by weight of “Kaoh Wax EB” (trade name; manufactured by Kao Corporation) as a lubricant, and “Leodol SP-S10V8” ( 1 part by weight of a product name (manufactured by Kao Corporation) was kneaded. The kneading conditions were a rotor rotation speed of 50 rpm, a floating weight pressure of 3 kg / cm ² , a kneading time of 5 minutes, and a kneading discharge temperature of 137 ° C.

  Next, after confirming that the temperature of the blend became 40 ° C., “Sunseller M” (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.) was used as a vulcanization accelerator to the blend using a 14-inch roll. 2.0 parts by weight, "Sunseller PZ" (trade name; manufactured by Sanshin Chemical Co., Ltd.) as a vulcanization accelerator 0.5 parts by weight, "Sunseller BZ" (trade name; Sanshin Chemical) as a vulcanization accelerator 1.5 parts by weight of Kogyo Co., Ltd., 1.5 parts by weight of “Sunseller BUR” (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.) as a vulcanization accelerator, and 0.5% of sulfur as a vulcanizing agent Part by weight was kneaded. The kneading conditions were as follows: roll temperature: front roll / rear roll = 65 ° C./50° C., roll rotation speed: front roll / rear roll = 13 rpm / 11.5 rpm, roll gap of 5 mm, and kneading time 8 minutes. -1 was prepared. This compound-1 was vulcanized at 160 ° C. for 15 minutes using a press molding machine to prepare a rubber sheet having a thickness of 2 mm. About the obtained vulcanizate, the ozone-proof test was done by the said method. The results are shown in Table 2. In addition, 31.25 parts by weight of “Neothrene HM804A” (trade name: Eiwa Kasei Kogyo Co., Ltd.) as a foaming agent and “Cell Paste K5” (trade name: Eiwa Kasei Kogyo Co., Ltd.) as a foaming aid are added to this formulation-1. ) Was mixed with 0.5 parts by weight and 4 parts by weight of “VESTA 18” (trade name; Inoue Lime Industry Co., Ltd.) as a hygroscopic agent. The kneading conditions are as follows: roll temperature is front roll / rear roll = 80 ° C./80° C., roll peripheral speed is front roll / rear roll = 13 rpm / 11.5 rpm, roll gap is 5 mm, and kneading time is 15 minutes. Product-2 was prepared. This rubber compound-2 was extruded under the conditions of a die temperature of 80 ° C. and a cylinder temperature of 60 ° C. using a 60 φmm extruder attached to a tube die (inner diameter / outer diameter 4/11 Φmm), and formed into a tube flat plate shape. This molded body was introduced into a vulcanizing tank simultaneously with molding and heated at a temperature of 180 ° C. for 10 minutes to carry out a crosslinking reaction and a foaming reaction to obtain a tubular sponge. Table 2 shows the physical property values of the tubular sponge.

[Example 2]
As in Example 1, except that an ethylene / propylene / non-conjugated polyene copolymer of EPDM-1 was used instead of an ethylene / propylene / non-conjugated polyene copolymer of EPDM-1 as the copolymer rubber. went. Table 2 shows physical property values of the sheet molded body and the tubular sponge.

Example 3
As in Example 1, except that an ethylene / propylene / non-conjugated polyene copolymer of EPDM-1 was used instead of an ethylene / propylene / non-conjugated polyene copolymer of EPDM-1 as the copolymer rubber. went. Table 2 shows physical property values of the sheet molded body and the tubular sponge.

Example 4
As in Example 1, except that an ethylene / propylene / non-conjugated polyene copolymer of EPDM-4 was used instead of the ethylene / propylene / non-conjugated polyene copolymer of EPDM-1 as the copolymer rubber. went. Table 2 shows physical property values of the sheet molded body and the tubular sponge.

[ Reference Example 5]
50 to 0 parts by weight of “Lureon 810 (trade name; Tosoh Corporation) as a vinyl chloride resin, and 160 to 140 weights of“ Hijilite H42M ”(trade name; manufactured by Showa Denko KK) as a flame retardant. Parts, and 60 parts by weight of magnesium hydroxide “KISUMA5B” (trade name; manufactured by Kyowa Chemical Industry Co., Ltd.) as a flame retardant was added in the same manner as in Example 1. Table 2 shows physical property values of the sheet molded body and the tubular sponge.

[ Reference Example 6]
As a flame retardant, aluminum hydroxide “Hijilite H42M” (trade name; manufactured by Showa Denko KK) is 140 to 160 parts by weight, and magnesium hydroxide “KISUMA5B” (trade name; manufactured by Kyowa Chemical Industry Co., Ltd.) is 60 weights. 100 parts by weight of parts, phosphorus-based flame retardant "TCP"; except for changing the (trade name Daihachi chemical industry Co., Ltd.) to 0 parts by weight from 20 parts by weight, were carried out in the same manner as in example 5. Table 2 shows physical property values of the sheet molded body and the tubular sponge.

[Comparative Example 1]
The copolymer rubber was changed to the EPDM-1 ethylene / propylene / nonconjugated polyene copolymer, but the EPDM-5 ethylene / propylene / nonconjugated polyene copolymer was used in the same manner as in Example 1. went. Table 2 shows physical property values of the sheet molded body and the tubular sponge.

[Comparative Example 2]
As in Example 1, except that an ethylene / propylene / non-conjugated polyene copolymer of EPDM-6 was used instead of the ethylene / propylene / non-conjugated polyene copolymer of EPDM-1 as the copolymer rubber. went. Table 2 shows physical property values of the sheet molded body and the tubular sponge.

[Comparative Example 3]
As in Example 1, except that an ethylene / propylene / nonconjugated polyene copolymer of EPDM-1 was used instead of an ethylene / propylene / nonconjugated polyene copolymer of EPDM-1 as the copolymer rubber. went. Table 2 shows physical property values of the sheet molded body and the tubular sponge.

[Comparative Example 4]
140 to 100 parts by weight of “Heidilite H42M” (trade name; manufactured by Showa Denko KK) as a flame retardant, and 60 to 50 parts by weight of “KISUMA5B” (trade name; manufactured by Kyowa Chemical Industry Co., Ltd.), The same procedure as in Reference Example 5 was performed except that “Diana Process Oil PS-430” (trade name; manufactured by Idemitsu Kosan Co., Ltd.) was changed from 20 parts by weight to 40 parts by weight as the softening agent. Table 2 shows physical property values of the sheet molded body and the tubular sponge.

  The rubber molded body of the present invention is obtained by crosslinking and foaming a rubber composition exhibiting sufficiently high foaming properties, and has both high flame retardancy and heat insulation properties and excellent smoothness of the sponge surface. Therefore, the surface of the sponge can be coated to provide functionality (strength improvement, slidability improvement, etc.), and the coated sponge used for heat insulation and damage prevention of pipes, pipes and tubes, and for automobiles It can be suitably used for a seal sponge.

Claims (5)

Ethylene-alpha-olefin-non-conjugated diene random copolymer [I], a vinyl resin and flame retardant chloride [II], the softening agent [III], and contains a blowing agent, [I], [II] And [III], the content of the formula (ii) is satisfied, and 5 to 50 parts by weight of a foaming agent is contained per 100 parts by weight of [I].
Copolymer [I]: ethylene [A], α-olefin [B] having 3 to 20 carbon atoms, and one molecule of carbon / carbon double bond that can be polymerized with a metallocene catalyst among carbon / carbon double bonds Non-conjugated polyene [C-1] having only one carbon atom in the molecule and non-conjugated polyene having two carbon-carbon double bonds polymerizable with a metallocene catalyst among two carbon-carbon double bonds in one molecule [ A copolymer synthesized using a metallocene catalyst, comprising a structural unit derived from C-2],
(1) The structural unit derived from an α-olefin [B] having 3 to 20 carbon atoms is 10 to 50 mol% in 100 mol% of all structural units,
(2) Mol% of structural units derived from non-conjugated polyene [C-1] in which only one carbon / carbon double bond that can be polymerized with a metallocene catalyst is present in one molecule. And a total of mol% of structural units derived from non-conjugated polyene [C-2] in which two carbon / carbon double bonds that can be polymerized with a metallocene catalyst are present in one molecule. 1.0 to 6.0 mol%,
(3) Mol% of structural units derived from non-conjugated polyene [C-1] in which only one carbon / carbon double bond that can be polymerized with a metallocene catalyst is present in one molecule. Of carbon and carbon double bonds that can be polymerized with a metallocene catalyst among the carbon and carbon double bonds and the mol% of the structural unit derived from non-conjugated polyene [C-2] that exists in one molecule ([C-1] / [C-2]) is 75/25 to 99.5 / 0.5,
(4) Mooney viscosity [ML _{1 + 4} (100 ° C.)] measured at 100 ° C. is 10 to 90,
(5) The apparent iodine value (IV) of the structural unit derived from the non-conjugated polyene [C-2] is 0.1 to 3.0 g / 100 g,
(6) A copolymer satisfying the following formula (i).
50> Flow activation energy (Ea) [KJ / mol]> 35 (i)
(A vinyl chloride resin and flame retardant [II]) / (copolymer [I] + softener [III]) ≧ 1.50 ··· ( ii)   The non-conjugated polyene [C-1] in which only one carbon / carbon double bond polymerizable with a metallocene catalyst exists in one molecule among the carbon / carbon double bonds according to claim 1 is 5-ethylidene-2. -Norbornene (ENB), a non-conjugated polyene [C-2] in which two carbon-carbon double bonds polymerizable with a metallocene catalyst among the carbon-carbon double bonds exist in one molecule is 5- The rubber composition according to claim 1, wherein the rubber composition is vinyl-2-norbornene (VNB). The rubber composition according to claim 1 or 2, wherein the copolymer [I] according to claim 1 is synthesized using a catalyst having a structure represented by the following formula (iii ').

In the formula (III ′), R ′ is a hydrogen atom, a hydrocarbyl group having 1 to 20 carbon atoms, R ″ is a hydrocarbyl group having 1 to 20 carbon atoms or a hydrogen atom, M is titanium, Y is —NR ^* —, Z ^* is —SiR ^* ₂ —, and each R ^* is independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms; One is 0, the other is 1, and when p is 0 and q is 1, M is in the +2 oxidation state and X ′ is 1,4-diphenyl-1,3-butadiene or When 1,3-pentadiene, p is 1 and q is 0, M is in the +3 oxidation state and X is 2- (N, N-dimethylamino) benzyl.   The rubber composition according to any one of claims 1 to 3, further comprising a crosslinking agent.   A flame retardant crosslinked foam, wherein the specific gravity obtained by crosslinking and foaming the rubber composition according to claim 4 is 0.03 to 0.3, and the surface roughness of the foam is 30 μm or less.