JP7088718B2 - Copolymer composition for foam and its foam - Google Patents

Description

The present invention relates to a copolymer composition for a foam and a foam suitable for obtaining a foam used for automobiles, building materials, home appliances and the like.

Foams typified by sponges applied to gaps in automobiles, building materials, home appliances, etc. are required to have high sealing properties and mechanical strength even under large deformation in order to block rain, wind, and sound. To. In addition, sponges used in the opening and closing parts of automobiles, building materials, home appliances, etc., especially heat insulating sponges used around radiators and outside the metal tubes of air conditioners, require design and mechanical strength in addition to sealing properties. It has been considered desirable that the bubbles in the sponge are closed cells rather than open cells.

Ethylene / α-olefin copolymers and ethylene / α-olefin / non-conjugated diene copolymers do not have unsaturated bonds in the main chain, so they are weather resistant, heat resistant and resistant compared to conjugated diene rubbers. It is used in the above sponge products because it has excellent ozone properties.

Then, in order to improve the sealing performance of the sponge product, it has been proposed to add a polyolefin resin to the ethylene / α-olefin / non-conjugated diene copolymer (Patent Document 1).

Japanese Unexamined Patent Publication No. 2000-212318

An object of the present invention is to obtain an ethylene / α-olefin / non-conjugated diene copolymer composition suitable for obtaining a foam having a low specific gravity and an excellent balance of foaming ratio, shrinkage ratio and mechanical strength. ..

Therefore, the present inventors have added two or more types of olefin polymers having different melting points and densities to an ethylene / α-olefin / non-conjugated polyene copolymer to have a low specific gravity, a continuous foaming rate, and a shrinkage rate. It has been found that an ethylene / α-olefin / non-conjugated diene copolymer composition suitable for obtaining a foam having an excellent balance of mechanical strength can be obtained.

That is, the present invention relates to a copolymer composition for foams, which comprises the following components (A) to (E).
(A) An ethylene / α-olefin / non-conjugated polyene copolymer (A) composed of ethylene, an α-olefin having 3 to 20 carbon atoms, and a non-conjugated polyene that satisfies the following requirements (a) to (c). ..
(A) The molar ratio [ethylene / α-olefin] of ethylene to α-olefin having 3 to 20 carbon atoms is in the range of 40/60 to 90/10.
(B) Iodine value is in the range of 1 to 50.
(C) The ultimate viscosity [η] measured in decalin at 135 ° C. is in the range of 2.2 to 6.0 dl / g.
(B) An olefin polymer (B) having a melting point of 50 to 100 ° C. and a density of 930 to 990 kg / m ³ as determined by DSC measurement.
(C) An olefin polymer (C) having a melting point in the range of 100 to 190 ° C. and a density of 895 kg / m ³ or more and less than 930 kg / m ³ as determined by DSC measurement.
(D) Cross-linking agent and (E) Foaming agent.

The copolymer composition for foam of the present invention has excellent fluidity during extrusion processing, and the foam obtained by cross-linking and foaming the copolymer composition for foam has a low specific density and forms a skin layer. However, it becomes a foam having high mechanical strength due to its design and closed cell formation.

<Ethylene / α-olefin / non-conjugated polyene copolymer (A)>
The ethylene / α-olefin / non-conjugated polyene copolymer (A) (hereinafter, may be referred to as “component (A)”), which is the main component of the copolymer composition for foam of the present invention, is used. A non-polymer containing two or more partial structures selected from the group consisting of ethylene (a), α-olefin (b) having 3 to 20 carbon atoms, and the following general formulas (I) and (II) in total. It has a structural unit derived from the conjugated polyene (c).

このような本発明に係るエチレン・α－オレフィン・非共役ポリエン共重合体（Ａ）は、上記（ａ）、（ｂ）、（ｃ）に由来する構造単位に加えて、さらに上記一般式（Ｉ）および（II）からなる群から選ばれる部分構造を分子中に１つのみ含む非共役ポリエン（ｄ）に由来する構成単位を有していてもよい。

The ethylene / α-olefin / non-conjugated polyene copolymer (A) according to the present invention has the above general formula (A) in addition to the structural units derived from the above (a), (b) and (c). It may have a structural unit derived from a non-conjugated polyene (d) containing only one partial structure selected from the group consisting of I) and (II) in the molecule.

Examples of the α-olefin (b) having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene and 1-. Examples thereof include decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-eikosen and the like. Of these, α-olefins having 3 to 8 carbon atoms such as propylene, 1-butene, 1-hexene, and 1-octene are preferable, and propylene is particularly preferable. Such an α-olefin has a relatively low raw material cost, the obtained ethylene / α-olefin / non-conjugated polyene copolymer exhibits excellent mechanical properties, and a molded product having rubber elasticity is obtained. It is preferable because it can be used. These α-olefins may be used alone or in combination of two or more.

That is, the ethylene / α-olefin / non-conjugated polyene copolymer (A) according to the present invention contains at least one structural unit derived from the α-olefin (b) having 3 to 20 carbon atoms. It may contain a structural unit derived from two or more kinds of α-olefins (b) having 3 to 20 carbon atoms.

Examples of the non-conjugated polyene (c) containing two or more partial structures selected from the group consisting of the general formulas (I) and (II) in the molecule include 5-vinyl-2-norbornene (VNB) and norbornadiene. Examples thereof include 1,4-hexadiene and dicyclopentadiene. Among these, it is preferable that the non-conjugated polyene (c) contains VNB because it is easily available, cross-linked is good, and the heat resistance of the obtained cross-linked foam is easily improved. Therefore, the non-conjugated polyene (c) is preferably contained. Is more preferably VNB. The non-conjugated polyene (c) may be used alone or in combination of two or more.

The ethylene / α-olefin / non-conjugated polyene copolymer (A) according to the present invention is derived from ethylene (a), α-olefin (b) having 3 to 20 carbon atoms, and the non-conjugated polyene (c). In addition to the structural unit, even if it contains a structural unit derived from a non-conjugated polyene (d) containing only one partial structure selected from the group consisting of the general formulas (I) and (II) in the molecule. good. Examples of such non-conjugated polyene (d) include 5-ethylidene-2-norbornene (ENB), 5-methylene-2-norbornene, 5- (2-propenyl) -2-norbornene, and 5- (3-butenyl). -2-Norbornene, 5- (1-Methyl-2-propenyl) -2-Norbornene, 5- (4-Pentenyl) -2-Norbornene, 5- (1-Methyl-3-butenyl) -2-Norbornene, 5 -(5-Hexenyl) -2-norbornene, 5- (1-methyl-4-pentenyl) -2-norbornene, 5- (2,3-dimethyl-3-butenyl) -2-norbornene, 5- (2-) Ethyl-3-butenyl) -2-norbornene, 5- (6-heptenyl) -2-norbornene, 5- (3-methyl-5-hexenyl) -2-norbornene, 5- (3,4-dimethyl-4- Pentenyl) -2-norbornene, 5- (3-ethyl-4-pentenyl) -2-norbornene, 5- (7-octenyl) -2-norbornene, 5- (2-methyl-6-heptenyl) -2-norbornene , 5- (1,2-dimethyl-5-hexenyl) -2-norbornene, 5- (5-ethyl-5-hexenyl) -2-norbornene, 5- (1,2,3-trimethyl-4-pentenyl) -2-Norbornene and the like. Among these, ENB is preferable because it is easily available, it is easy to control the crosslinking rate at the time of crosslinking, and it is easy to obtain a crosslinked foam having good mechanical properties.

The non-conjugated polyene (d) may be used alone or in combination of two or more. The ethylene / α-olefin / non-conjugated polyene copolymer of the present invention comprises a non-conjugated polyene (d) containing only one partial structure selected from the group consisting of the general formulas (I) and (II) in the molecule. When the constituent unit derived from the substance is contained, the proportion thereof is not particularly limited as long as the object of the present invention is not impaired, but is usually 0 to 20% by weight, preferably 0 to 8% by weight, and more preferably 0. It is included in a weight fraction of about 01 to 8% by weight (however, the total weight fraction of (a), (b), (c), and (d) is 100% by weight).

As described above, the ethylene / α-olefin / non-conjugated polyene copolymer (A) according to the present invention contains ethylene (a), α-olefin (b) having 3 to 20 carbon atoms, and the above-mentioned non-conjugated polyene. It is a copolymer having a structural unit derived from (c) and, if necessary, the non-conjugated polyene (d), and satisfies the requirements of the following requirements (a) and (b).

[Requirement (a)]
Requirement (a) specifies that the molar ratio of ethylene / α-olefin in the ethylene / α-olefin / non-conjugated polyene copolymer (A) according to the present invention satisfies 40/60 to 90/10. The molar ratio is preferably 50/50 to 90/10, more preferably 55/45 to 85/15, and even more preferably 55/45 to 78/22. In such an ethylene / α-olefin / non-conjugated polyene copolymer according to the present invention, the crosslinked foam obtained by crosslinking and foaming exhibits excellent rubber elasticity, and is excellent in mechanical strength and flexibility. Therefore, it is preferable.

The amount of ethylene (content of the structural unit derived from ethylene (a)) and the amount of α-olefin (configuration derived from α-olefin (b)) in the ethylene / α-olefin / non-conjugated polyene copolymer (A). The unit content) can be determined by ¹³ C-NMR.

[Requirement (b)]
The iodine value of the ethylene / α-olefin / non-conjugated polyene copolymer (A) of the present invention is usually 1 to 50 g / 100 g, preferably 4 to 32, and more preferably 15 to 32. .. When the iodine value is in this range, the crosslink density is high and the mechanical strength is excellent.

The ethylene / α-olefin / non-conjugated polyene copolymer (A) according to the present invention is specifically produced, for example, by adopting the method described in the metallocene catalyst described in International Publication No. 2015/122495. can do.

<Olefin polymer (B)>
The olefin polymer (B) (hereinafter, may be referred to as “component (B)”), which is one of the components contained in the copolymer composition for foam of the present invention, is determined by DSC measurement. It is an olefin polymer having a melting point of 50 to 100 ° C., preferably 60 to 90 ° C., and a density of 930 to 990 kg / m ³ , preferably 935 to 965 kg / m ³ .

The component (B) according to the present invention preferably has a melt flow rate (MFR, 230 ° C., 2.16 kg load, 10 minutes) in the range of 1.0 to 40 g / 10 minutes, more preferably in addition to the above physical properties. It is in the range of 1.0 to 35 g / 10 minutes.

The component (B) according to the present invention is a homopolymer of an α-olefin having 2 to 20 carbon atoms, a copolymer of different α-olefins, an α-olefin having 2 to 20 carbon atoms and another vinyl compound, for example. , Vinyl acetate, (meth) acrylic acid ester, (meth) acrylic acid, styrene, and the like, which is a polymer containing α-olefin having 2 to 20 carbon atoms in at least a part of its constituent components.

Specific examples of the component (B) according to the present invention include medium-density polyethylene (MDPE), high-pressure low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and an ethylene-vinyl acetate copolymer (EVA). , Ethethylene-α-olefin copolymer composed of polyethylene and α-olefin having 3 to 20 carbon atoms, preferably 3 to 8 carbon atoms, and propylene and α-olefin having 2 to 20 carbon atoms, preferably 4 to 8 carbon atoms. Examples thereof include a propylene / α-olefin copolymer, a 1-butene / α-olefin copolymer composed of 1-butene and an α-olefin having 3 to 20 carbon atoms, preferably 3 to 8 carbon atoms.

The component (B) according to the present invention is not limited to the above-mentioned specific examples as long as the melting point and the density satisfy the above-mentioned ranges.
Among these polymers, the component (B) according to the present invention is preferably an ethylene-vinyl acetate copolymer, particularly ethylene-vinyl acetate having a vinyl acetate content of 1 to 50% by weight and further 15 to 35% by weight. Vinyl copolymers are preferred.

<Olefin polymer (C)>
The olefin polymer (C) (hereinafter, may be referred to as "component (C)"), which is one of the components contained in the copolymer composition for foam of the present invention, is determined by DSC measurement. An olefin-based polymer having a melting point in the range of 100 to 190 ° C., preferably 100 to 135 ° C., and a density of 895 kg / m ³ or more and less than 930 kg / m ³ , preferably 900 to 915 kg / m ³ . ..

The component (C) according to the present invention preferably has a lutoflorate (MFR, 230 ° C., 2.16 kg load, 10 minutes) in the range of 1.0 to 25 g / 10 minutes, more preferably in addition to the above physical properties. It is in the range of 1.5 to 5 g / 10 minutes.

The component (C) according to the present invention is a homopolymer of an α-olefin having 2 to 20 carbon atoms, a copolymer of different α-olefins, an α-olefin having 2 to 20 carbon atoms and another vinyl compound, for example. , A polymer containing α-olefin having 2 to 20 carbon atoms in at least a part of its constituent components, such as a polymer with vinyl acetate, (meth) acrylic acid ester, (meth) acrylic acid, styrene and the like.

Specific examples of the component (C) according to the present invention include high-density polyethylene (HDPE), medium-density polyethylene (MDPE), linear low-density polyethylene (LLDPE), ethylene / vinyl acetate copolymer resin (EVA), and ethylene. An ethylene-based polymer such as an ethylene / α-olefin copolymer composed of α-olefin having 3 to 20 carbon atoms, preferably 3 to 8 carbon atoms, a propylene homopolymer, and propylene having 2 to 20 carbon atoms, preferably 2 carbon atoms. A propylene-based polymer (including a propylene block copolymer, a propylene random copolymer, etc.) such as a propylene / α-olefin copolymer composed of 8 to 8 α-olefins, a 1-butene homopolymer, and a 1-butene. 1-butene polymer such as 1-butene / α-olefin copolymer composed of α-olefin having 3 to 20 carbon atoms, preferably 3 to 8 carbon atoms, 4-methyl-1-pentene homopolymer, 4 4-Methyl-1-pentene-based weight such as 4-methyl-1-pentene / α-olefin copolymer composed of -methyl-1-pentene and α-olefin having 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms. Coalescence etc. can be mentioned.
The component (C) according to the present invention is not limited to the above-mentioned specific examples as long as the melting point and the density satisfy the above-mentioned ranges.

<Crosslinking agent (D)>
The cross-linking agent (D), which is one of the components contained in the copolymer composition for foam of the present invention, is a cross-linking agent widely used as a cross-linking agent for rubber and plastic, and specifically, sulfur. , Sulfur chloride, sulfur dichloride, morpholine disulfide, alkylphenol disulfide, tetramethylthium disulfide and selenium dithiocarbamate. Among these cross-linking agents, sulfur-based cross-linking agents are preferable, and sulfur and tetramethylthiuram disulfide are more preferable.

<Effervescent agent (E)>
As the foaming agent (E), which is one of the components contained in the copolymer composition for foam of the present invention, various known foaming agents can be used. Specifically, inorganic foaming agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, ammonium nitrite; N, N'-dimethyl-N, N'-dinitrosoterephthalamide, N, N'-di Nitroso compounds such as nitrosopentamethylenetetramine; azo compounds such as azodicarboxylicamide, azobisisobutyronitrile, azobiscyclohexylnitrile, azodiaminobenzene, barium azodicarboxylate; benzenesulfonyl hydrazide, toluenesulfonylhydrazide, p, p Sulfonyl hydrazide compounds such as'-oxybis (benzenesulfonyl hydrazide) (OBSH), diphenylsulfone-3,3'-disulfonylhydrazide; azodes such as calcium azide, 4,4'-diphenyldisulfonyl azide, p-toluenesulfonyl azide. Examples include compounds.

As the foaming agent (E) according to the present invention, either a non-supported type or a supported type supported on an inorganic powder or the like may be used, but the foaming agent (E) has the same specific gravity as compared with the case where the supported type is used. Non-supported foaming agents are preferable because they have a low water absorption rate, excellent sealing performance (soundproofing, waterproofing, vibration-proofing), and excellent kneading workability.

Further, if necessary, a foaming aid may be used in combination with the foaming agent. The addition of the foaming aid is effective in controlling the decomposition temperature of the foaming agent and homogenizing the bubbles. Specific examples of the foaming aid include organic acids such as salicylic acid, phthalic acid, stearic acid and oxalic acid, urea and its derivatives.
When the component (A) contains a foaming aid, the blending amount of the foaming aid is usually 1 to 100 parts by mass, preferably 2 to 80 parts by mass with respect to 100 parts by mass of the foaming agent. Used.

<Copolymer composition for foam>
The copolymer composition for a foam of the present invention comprises the ethylene / α-olefin / non-conjugated polyene copolymer (A), the olefin polymer (B), the olefin polymer (C), and the crosslinked polymer. A composition containing the agent (D) and the foaming agent (E), preferably the weight fraction (X _A ) [component (A) / copolymer of the copolymer (A) in the copolymer composition. The composition] is in the range of 0.16 to 0.29, more preferably in the range of 0.21 to 0.27.

The copolymer composition for a foam of the present invention preferably has a weight fraction (X _B ) [component (B) / copolymer composition] of the olefin polymer (B) in the copolymer composition. It is in the range of 0.02 to 0.10, more preferably 0.02 to 0.09.

The foam copolymer composition of the present invention preferably contains 5 to 100 parts by mass, preferably 5 to 60 parts by mass, and more preferably 10 to 40 parts by mass of the component (B) with respect to 100 parts by mass of the component (A). 5 to 100 parts by mass, preferably 5 to 60 parts by mass, more preferably 10 to 40 parts by mass, and 0 to 12.0 parts by mass, preferably 1.0 to 1 part by mass of the component (C). 10.0 parts by mass, more preferably 1.5 to 9.0 parts by mass, and component (E) in the range of 20 to 100 parts by mass, preferably 30 to 60 parts by mass, more preferably 40 to 50 parts by mass. It is a composition containing.

By including the component (D) as a cross-linking agent in the copolymer composition for a foam of the present invention in the above range, a cross-linked foam having high rigidity can be obtained.
In the copolymer composition for foam of the present invention, in addition to the above-mentioned component (D) and component (E), other components include, for example, a vulcanization accelerator, a vulcanization aid, a plasticizer, a reinforcing agent, and the like. Examples thereof include various additives such as an inorganic filler, an antiaging agent (stabilizer), a processing aid, and an activator.

<Vulcanization accelerator>
When the copolymer composition for foam of the present invention contains a sulfur-based compound as a cross-linking agent, it is preferable to use a vulcanization accelerator in combination. Examples of the vulcanization accelerator include N-cyclohexyl-2-benzothiazolesulfenamide, N-oxydiethylene-2-benzothiazolesulfenamide, N, N'-diisopropyl-2-benzothiazolesulfenamide, and 2-mercapto. Thiazoles such as benzothiazole, 2- (2,4-dinitrophenyl) mercaptobenzothiazole, 2- (2,6-diethyl-4-morpholinothio) benzothiazole and dibenzothiadyldisulfide; diphenylguanidine, triphenylguanidine And guanidines such as diorsotrilguanidine; acetoaldehyde-aniline condensates, butylaldehyde-aniline condensates and aldehyde amines; imidazolines such as 2-mercaptoimidazoline; thioureas such as diethylthiourea and dibutylthiourea; tetramethylthiurammono Thiuram type such as sulfide; dithioate type such as zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate and telluryl diethyldithiocarbamate; zantate type such as zinc dibutylxatogenate; other zinc flower (zinc oxide) and the like. Of these, 2-mercaptobenzothiazole is preferred.

When sulfur is used as the cross-linking agent, it is preferable to use a vulcanization accelerator in combination, and examples of the vulcanization accelerator include tetramethylthiuram disulfide and the like in addition to the above-mentioned vulcanization accelerator. Of these, 2-mercaptobenzothiazole and tetramethylthiuram disulfide are preferred.

The vulcanization accelerator according to the present invention may be used alone or in combination of two or more.
When the copolymer composition for foam of the present invention contains a vulcanization accelerator, the blending amount thereof is usually 0.1 to 20 parts by mass, preferably 0, with respect to 100 parts by mass of the component (A). It is 2 to 15 parts by mass, more preferably 0.5 to 10 parts by mass. When the blending amount of the vulcanization accelerator is within the above range, the mechanical strength and heat aging resistance of the obtained foam are excellent, which is preferable.

<Vulcanization aid>
When the copolymer composition for foam of the present invention contains an organic peroxide as a cross-linking agent, it is preferable to use a vulcanization aid in combination. As vulcanization aids, quinone-dioxime type such as p-quinone dioxime; acrylic type such as ethylene glycol dimethacrylate and trimethylolpropanetrimethacrylate; allyl type such as diallyl phthalate and triallyl isocyanurate; other maleimide type; divinyl Examples include benzene.

The vulcanization aid according to the present invention may be used alone or in combination of two or more.
The blending amount of the vulcanization aid according to the present invention is usually 0.5 to 2 mol, preferably 0.5 to 1.5 mol, more preferably almost equimolar, with respect to 1 mol of the organic peroxide used. It is desirable to use the amount of.

<Plasticizer>
Examples of the plasticizer (softener) according to the present invention include plasticizers usually used for rubber. Specific examples thereof include process oil, lubricating oil, paraffin oil, liquid paraffin, petroleum asphalt, vaseline, coal tar, castor oil, flaxseed oil, sub, beeswax, atactic polypropylene, and bearloinden resin. Of these, process oil and paraffin oil are particularly preferably used.

The plasticizer according to the present invention may be used alone or in combination of two or more.
The plasticizer according to the present invention is usually used in a proportion of 20 parts by mass or more with respect to 100 parts by mass of the component (A) in order to obtain good kneading property in the copolymer composition for foam. When the process oil is used as the plasticizer, the blending amount thereof is preferably 20 to 150 parts by mass, more preferably 30 to 120 parts by mass with respect to 100 parts by mass of the component (A).

<Reinforcing agent and inorganic filler>
The copolymer composition for a foam of the present invention has a reinforcing agent or a reinforcing agent in order to improve mechanical properties such as tensile strength, tear strength and wear resistance of the obtained foam and further reduce the molding shrinkage rate. It is preferable to add an inorganic filler.

Specific examples of the reinforcing agent and the inorganic filler according to the present invention include Asahi # 55G, Asahi # 60G (all manufactured by Asahi Carbon Co., Ltd.), Sisto (SRF, GPF, FEF, MAF, HAF, ISAF, etc.). Carbon black (manufactured by Tokai Carbon Co., Ltd.) of SAF, FT, MT, etc.), those obtained by surface-treating these carbon blacks with a silane coupling agent, silica, activated calcium carbonate, fine powder talc, fine powder silicic acid, etc. Can be used.

Further, as the inorganic filler, light calcium carbonate, heavy calcium carbonate, talc, clay and the like can be used. Of these, Asahi # 55G, Asahi # 60G, and "Seest HAF" carbon black are preferred.

The reinforcing agent and / or the inorganic filler according to the present invention may be used alone or in combination of two or more.
The blending amount of the reinforcing agent and / or the inorganic filler according to the present invention is usually 1 to 500 parts by mass, preferably 1 to 400 parts by mass, and more preferably 1 to 300 parts by mass with respect to 100 parts by mass of the component (A). Is. When the blending amount of the reinforcing agent and / or the inorganic filler is within the above range, the obtained foam is suitable because it has excellent mechanical strength.

<Anti-aging agent (stabilizer)>
By adding an antiaging agent to the copolymer composition for foam of the present invention, it is possible to prolong the life of the obtained foam. As such an anti-aging agent, conventionally known anti-aging agents such as amine-based anti-aging agents, phenol-based anti-aging agents, sulfur-based anti-aging agents and the like can be used.

Specific examples of the anti-aging agent according to the present invention include aromatic secondary amine-based anti-aging agents such as phenylbutylamine, N, N-di-2-naphthyl-p-phenylenediamine, dibutylhydroxytoluene, and tetrakis [ Methylene (3,5-di-t-butyl-4-hydroxy) hydrocinnamate] Phenolic anti-aging agents such as methane; bis [2-methyl-4- (3-n-alkylthiopropionyloxy) -5-t -Butylphenyl] Thioether-based anti-aging agents such as sulfide; Dithiocarbamate-based anti-aging agents such as nickel dibutyldithiocarbamate; 2-mercaptobenzoimidazole, 2-zinc salt of 2-mercaptobenzoimidazole, dilaurylthiodipropionate, di Examples thereof include sulfur-based antiaging agents such as stearylthiodipropionate.

The anti-aging agent according to the present invention can be used alone or in combination of two or more, and the blending amount of the anti-aging agent is usually 0.01 to 10 mass by mass with respect to 100 parts by mass of the component (A). Parts, preferably 0.01 to 7 parts by mass, more preferably 0.01 to 5 parts by mass. When the blending amount of the anti-aging agent is within the above range, the heat-resistant aging property of the obtained foam is excellent, which is preferable.

<Processing aid>
As the processing aid according to the present invention, those generally blended in rubber as a processing aid can be widely used. Specific examples thereof include ricinoleic acid, stearic acid, palmitic acid, lauric acid, barium stearate, zinc stearate, calcium stearate, zinc lauric acid and esters. Of these, stearic acid is preferred.

The processing aid according to the present invention may be used alone or in combination of two or more.
When the processing aid according to the present invention is blended in the copolymer composition for foam, it is usually 30 parts by mass or less, preferably 25 parts by mass or less, and more preferably 20 parts by mass with respect to 100 parts by mass of the component (A). It can be appropriately blended in an amount of parts by mass or less. When the blending amount of the processing aid is within the above range, it is preferable because it is excellent in processability such as kneading processability, extrusion processability, and injection moldability.

<Activator>
Examples of the activator according to the present invention include glycols such as polyethylene glycol and diethylene glycol; amines such as di-n-butylamine and triethanolamine.

One type according to the present invention may be used alone, or two or more types may be used.
When the activator according to the present invention is blended in the copolymer composition for foam, the blending amount of the activator is 0.2 to 10 parts by mass, preferably 0 with respect to 100 parts by mass of the component (A). .3 to 5 parts by mass, more preferably 0.5 to 4 parts by mass.

<Method for preparing copolymer composition for foam>
In the copolymer composition for foam of the present invention, the component (A), the component (B), the component (C), the component (D) and the component (E) are usually used as a rubber kneader in a Banbury mixer. , Can be prepared by kneading with the other components as needed using an internal mixer, a kneader, an open roll, or the like. The kneading temperature in this case is not particularly limited, but is preferably 80 to 250 ° C., more preferably 80 to 200 ° C., and the kneading time is preferably 1 to 20 minutes, more preferably 1 to 10 minutes. The mixing specific energy is preferably 0.001 to 10 kW · h / kg.

Further, in the copolymer composition for foam of the present invention, the above-mentioned components (A) to (E) and, if necessary, a vulcanization accelerator and a defoaming agent, using rolls such as open rolls. A copolymer for foams obtained by additionally mixing a foaming aid, a vulcanization aid, etc., kneading with a roll temperature of preferably 40 to 80 ° C. and a kneading time of preferably 5 to 30 minutes, and then dispensing the mixture. It may be a polymer composition.

<Crosslinked foam>
The crosslinked foam of the present invention is obtained by crosslinking and foaming the above-mentioned copolymer composition for foam.
The crosslinked foam of the present invention has a specific gravity in the range of 0.06 or less, preferably 0.05 to 0.02, and has an open cell ratio (hereinafter referred to as continuous foam ratio) of 10% or less, preferably 2 to 9. There are the following ranges, and the tensile breaking strength (TB) is in the range of 40 kPa or more, preferably 50 to 120 kPa.

The crosslinked foam of the present invention can be obtained by molding the copolymer composition for a foam of the present invention by an extrusion molding method, a transfer molding method, an injection molding method, a mold molding method, or a press molding method. .. Specifically, the foam copolymer composition obtained by the above method is extruded into a product shape by a rubber extruder, and then introduced into a vulcanization tank, where hot air, a fluidized bed, and a molten salt tank are used. It can be prepared by vulcanization and foaming by heating by means such as (LCM), PCM (Powder Curing Medium or Powder Curing Method) or microwave. Preferably, it can be obtained by continuous vulcanization and foaming by continuous extrusion using a hot air vulcanizer (HAV), LCM, PCM, or HAV and decimeter wave (UHF).

As the conditions for the above-mentioned crosslinking, the crosslinking temperature is usually 140 to 300 ° C., preferably 150 to 270 ° C., more preferably 150 to 250 ° C., and the crosslinking time is usually 0.5 to 30 minutes, preferably 0.5. It is ~ 20 minutes, more preferably 0.5 ~ 15 minutes.

The foam of the present invention can also be obtained by preforming the copolymer composition for a foam of the present invention by the above-mentioned molding method or the like and irradiating it with an electron beam.
In this case, an electron beam having an energy of 0.1 to 10 MeV may be irradiated so that the absorbed dose is usually 0.5 to 35 Mrad, preferably 0.5 to 20 Mrad, and more preferably 1 to 10 Mrad.

<Use>
The crosslinked foam of the present invention is suitably used in fields where weather resistance, heat aging resistance, abrasion resistance, low temperature flexibility and the like are required. Specifically, automobile parts, marine parts, civil engineering and construction parts, medical parts, electrical and electronic equipment parts, transport equipment and leisure parts, hoses (radiator hoses, heater hoses, etc.), anti-vibration rubber, etc. It is suitably used for sheets, various belts, various packings, sealing materials, potting materials, coating materials, adhesives and the like.

Automotive parts include, for example, glass run channels, weather strip sponges, door opening trims, sealing members, grommet, automotive engine gaskets, electrical components or oil filter sealing materials; Igniter HID or automotive hybrid IC potting materials; automobiles. Coating materials for bodies, automobile windowpanes, engine control boards; gaskets such as oil pans or timing belt covers, moldings, headlamp lenses, sunroof seals, and adhesives for mirrors. Examples of weatherstrip sponges include door weatherstrips, trunk weatherstrips, luggage weatherstrips, roof side rail weatherstrips, sliding door weatherstrips, ventilator weatherstrips, sliding roof weatherstrips, front window weatherstrips, rear window weatherstrips, etc. Examples include quarter window weather strips, lock pillar weather strips, door glass outer weather strips, and door glass inner weather strips.

These automobile parts are often molded by extrusion molding, and in this case, in particular, the kneadability of the copolymer composition for foam and the compatibility of the components contained in the copolymer composition are determined. It greatly affects the properties of the obtained foam. Since the copolymer composition for foam of the present invention is excellent in kneadability and compatibility of the components contained in the composition, a crosslinked foam having excellent physical properties can be obtained even when a molded body is formed by extrusion molding. be able to.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
The polymers used in Examples and Comparative Examples are as follows.

[Component (A)]
The following ethylene / propylene / ENB copolymer was used as the component (A).
Ethylene / propylene / ENB copolymer [Component (A-1) (trade name: Mitsui EPT, 8030M (manufactured by Mitsui Chemicals, Inc.), structural unit content derived from ethylene: 47% by mass, 5-ethylidene-2) -Structural unit content derived from norbornene (ENB): 9.5% by mass, Mooney viscosity [ML1 + 4 (100 ° C)]: 32,

[Component (B)]
The following ethylene-vinyl acetate copolymer was used as the component (B).
Ingredient (B-1) Ethylene-vinyl acetate copolymer (trade name: Evaflex Brand name: EVA150 (manufactured by Mitsui DuPont Polychemical Co., Ltd.) Vinyl acetate Content: 33% by weight, Density: 960 kg / m ³ , Melting point : 61 ° C., and MFR: 30 g / 10 minutes.
Ingredients (B-2) Ethylene-vinyl acetate copolymer (trade name: Evaflex Brand name: EVA170 (manufactured by Mitsui DuPont Polychemical Co., Ltd.) Vinyl acetate Content: 33% by weight, Density: 960 kg / m ³ , Melting point : 62 ° C., and MFR: 1 g / 10 minutes.
Ingredients (B-3) Ethylene-vinyl acetate copolymer (trade name: Evaflex Brand name: EVA450 (manufactured by Mitsui DuPont Polychemical Co., Ltd.) Vinyl acetate Content: 19% by weight, Density: 940 kg / m ³ , Melting point : 84 ° C., and MFR: 15 g / 10 minutes.
Ingredients (B-4) Ethylene-vinyl acetate copolymer (trade name: Evaflex Brand name: V523 (manufactured by Mitsui DuPont Polychemical Co., Ltd.) Vinyl acetate Content: 33% by weight, Density: 960 kg / m ³ , Melting point : 63 ° C., and MFR: 14 g / 10 minutes.

[Component (C)]
The following ethylene / 1-hexene copolymer was used as the component (C).
Melting point: 116 ° C, density: 913 kg / m ³ , MFR: 2.0 g / 10 min ethylene / 1-hexene copolymer: trade name Evolu SP1520 [component (C-1)] [manufactured by Prime Polymer Co., Ltd.] Was used.
The compounding agents used in Examples and Comparative Examples are shown below.

[Crosslinking agent (D)]
Sulfur (manufactured by Junsei Chemical Co., Ltd.)
[Vulcanization aid]
Activated zinc oxide (trade name: META-Z102 (manufactured by Inoue Lime Industry Co., Ltd.))
[Vulcanization accelerator]
(1-1) Thiazole-based vulcanization accelerator: 2-mercaptobenzothiazole (trade name: Sunseller M, manufactured by Sanshin Chemical Industry Co., Ltd.)
(1-2) Dithiocarbamate-based vulcanization accelerator: Zinc dibutyldithiocarbamate (trade name: Sunseller BZ manufactured by Sanshin Chemical Industry Co., Ltd.)
(1-3) Dithiocarbamate-based vulcanization accelerator: Zinc diethyldithiocarbamate (trade name: Sunseller PZ manufactured by Sanshin Chemical Industry Co., Ltd.)
(1-4) Thiourea-based vulcanization accelerator: N, N'-dibutylthiourea (trade name: Sunseller BUR Sanshin Chemical Industry Co., Ltd.)

[Effervescent agent (E)]
Azodicarbonamide (trade name: Neoslen HM80A manufactured by Eiwa Kasei Kogyo Co., Ltd.)
[Effervescent aid]
Urea (trade name: Neoslen HM51U manufactured by Eiwa Kasei Kogyo Co., Ltd.)
[Processing aid]
Stearic acid (trade name: powdered stearic acid Sakura NOF CORPORATION))
[Activator]
Polyethylene glycol (trade name: PEG # 4000 manufactured by Lion Corporation)
[Reinforcing agent]
Carbon black (Product name: Asahi # 50G, manufactured by Asahi Carbon Co., Ltd.)
[Inorganic filler]
Calcium carbonate (trade name: Whiten SB Shiraishi Calcium Co., Ltd.)
[Softener]
Paraffin oil (trade name: Diana Process Oil PS-430, manufactured by Idemitsu Kosan Co., Ltd.)
The measurements and tests obtained in the examples and comparative examples were performed as follows.

<Physical characteristics of foam>
<< Tensile breaking point stress (TB) and tensile breaking point elongation (EB) >>
The crosslinked foam sheets obtained in Examples and Comparative Examples were punched out to prepare a No. 3 dumbbell test piece described in JIS K 6251 (2001). Using this test piece, a tensile test was conducted under the conditions of a measurement temperature of 25 ° C. and a tensile speed of 500 mm / min according to the method specified in JIS K 6251, and the tensile breaking point stress (TB) and the tensile breaking point elongation (EB) were performed. Was measured.

《Continuous foam rate》
A 20 mm × 20 mm test piece was punched from the crosslinked foam vulcanized with hot air, and the pressure was reduced to 125 mmHg and 635 mmHg at a position 50 mm below the water surface, and the mixture was held for 3 minutes. Subsequently, after returning to atmospheric pressure for 3 minutes, the weight of the test piece absorbed in water was measured, and the continuous foam ratio (Wa) was calculated from the following formula.
Wa (%) = [(W2-W1) / W1] x 100
W1: Weight before immersion (g), W2: Weight after immersion (g)

"Shrinkage factor"
Within 30 seconds after being taken out of the vulcanization tank, it was cut to a length of 1 m, the length was measured (L0), the length after cooling (after 30 minutes had passed) (L1) was measured, and the shrinkage rate was calculated from the following formula. It was set to (%).
Shrinkage rate (%) = (L0-L1) / L0 × 100

[Example 1]
Using an MS type pressurized kneader (manufactured by Moriyama Co., Ltd.), 2000 g (100 parts by mass) of the component (A-1) and 200 g (10 parts by mass) of the above ethylene / 1-hexene copolymer [component (C-1)]. ) And 200 g (10 parts by mass) of the above ethylene / vinyl acetate copolymer [component (B-1)] were kneaded (total kneading time: 10 minutes).

Next, using MIXTRON BB MIXER (manufactured by Kobe Steel, Ltd., BB-4 type, volume 2.95 L, rotor 4WH), a filling rate of 72% and a conventional method (total kneading time of 5 minutes). 72 g (8 parts by mass) of vulcanization aid, 18 g (2 parts by mass) of processing aid, 9 g (1 part by mass) of activator, 270 g (30 parts by mass) of reinforcing material, and filling with respect to 1080 g of the obtained kneaded product. 1350 g (150 parts by mass) of the material and 450 g (50 parts by mass) of the softening material were kneaded to obtain a compound.

Subsequently, using an 8-inch two-roll kneader, the vulcanization accelerator 1-1 16.2 g (1.8 parts by mass) and the vulcanization accelerator 1-2 16.2 g (1.8) were added to the above formulation. Vulcanization accelerator 1-3 16.2 g (1.8 parts by mass), vulcanization accelerator 1-4 16.2 g (1.8 parts by mass), vulcanization agent 16.2 g (1.8 parts by mass) (By mass), 450 g (50 parts by mass) of the foaming agent, and 4.5 g (0.5 parts by mass) of the foaming aid were added and kneaded to obtain a kneaded product.

The obtained kneaded product is extruded by a rubber extruder (manufactured by Mitsuha Seisakusho Co., Ltd.) having a diameter of 50 mm, and is used for a sheet-shaped foam having a length of 2000 cm, a width of 2 cm, and a thickness of 0.6 cm. A copolymer composition was prepared. The temperature condition of the extruder was HD / C2 / C1 / SC = 80/70/60/50 ° C.

This composition was crosslinked and foamed at 170 ° C. for 8 minutes in a hot air vulcanization tank (manufactured by Microelectronics Co., Ltd.) to obtain a crosslinked foam.
The physical characteristics of the obtained crosslinked foam were measured by the method described above. The results are shown in Table 1.

[Examples 2 to 4]
The same procedure as in Example 1 was carried out except that the components shown in Table 1 were used instead of the copolymer composition for foam used in Example 1 to obtain a copolymer composition for foam and a crosslinked foam. rice field.
The physical characteristics of the obtained crosslinked foam were measured by the method described above. The results are shown in Table 1.

[Comparative Examples 1 to 4]
The same procedure as in Example 1 was carried out except that the components shown in Table 1 were used instead of the copolymer composition for foam used in Example 1 to obtain a copolymer composition for foam and a crosslinked foam. rice field.
The physical characteristics of the obtained crosslinked foam were measured by the method described above. The results are shown in Table 1.

Claims (4)

A copolymer composition for a foam, which is a copolymer composition containing the following components (A) to (E), wherein the copolymer composition satisfies the following requirement (II).
(A) An ethylene / α-olefin / non-conjugated polyene copolymer (A) composed of ethylene, an α-olefin having 3 to 20 carbon atoms, and a non-conjugated polyene that satisfies the following requirements (a) to (c). ..
(A) The molar ratio [ethylene / α-olefin] of ethylene to α-olefin having 3 to 20 carbon atoms is in the range of 40/60 to 90/10.
(B) Iodine value is in the range of 1 to 50.
(C) The ultimate viscosity [η] measured in decalin at 135 ° C. is in the range of 2.2 to 6.0 dl / g.
(B) An olefin polymer (B) having a melting point of 50 to 100 ° C. and a density of 930 to 990 kg / m ³ as determined by DSC measurement.
(C) An olefin polymer (C) having a melting point in the range of 100 to 190 ° C. and a density of 895 kg / m ³ or more and less than 930 kg / m ³ as determined by DSC measurement.
(D) Cross-linking agent and (E) Foaming agent.
(II) The weight fraction X _B of the olefin polymer (B) with respect to the copolymer composition is in the range of 0.02 to 0.10.
However, neither the olefin-based polymer (B) nor the olefin-based polymer (C) contains a non-conjugated polyene as a copolymerization component. 5 to 100 parts by mass of the olefin polymer (B) and 5 to 100 parts by mass of the olefin polymer (C) are crosslinked with respect to 100 parts by mass of the ethylene / α-olefin / non-conjugated polyene copolymer (A). The copolymer composition for a foam according to claim 1, wherein the agent (D) is contained in an amount of 1.0 to 12.0 parts by mass and the foaming agent (E) is contained in an amount of 20 to 100 parts by mass. A foam that satisfies the following requirements (i) to (iii), which is obtained from the copolymer composition for a foam according to any one of claims 1 or 2.
(I) Shrinkage rate is 1.00% or less,
(Ii) The open cell ratio is 1 to 20%,
(Iii) The ethylene-vinyl acetate copolymer in which the olefin polymer (B) has a vinyl acetate content in the range of 1 to 50% by weight. A sealing material containing the foam according to claim 3.