JP2010280777A - Rubber composition and rubber molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition showing excellent moldability because of its high green strength at relatively high temperatures (50-100°C), and to provide a rubber molded product obtained by vulcanizing the rubber composition and having mechanical properties and rubber elasticity in a well-balanced state. <P>SOLUTION: The rubber composition contains a resin obtained by micro-dispersing 2-15 pts.wt. of a polyolefin resin (B) having a melting point of 125-170°C in a molten state in 100 pts.wt. of an ethylene-α-olefin-nonconjugated diene random copolymer (A), and 30-240 pts.wt. of a filler. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rubber composition and a rubber molded body obtained by vulcanizing the rubber composition. More particularly, it relates to a rubber composition having improved green strength (strength before cross-linking), and more specifically, a rubber composition having excellent handling properties during molding and good extrudability, and mechanical properties. The present invention relates to a rubber molded body having a good balance of rubber elasticity.

  Generally, a rubber composition is prepared by formulating and kneading raw material rubber, a filler, a plasticizer and a crosslinking agent, a lubricant, an anti-aging agent, and the like in a desired ratio according to applications and purposes. At that time, a lot of high filling is possible because the production cost can be reduced by blending a lot of fillers (carbon black, various fillers, etc.) and plasticizers that are relatively cheap compared to raw rubber. Rubber compositions have been investigated so far. On the other hand, when a large amount of filler or oil is blended, the green strength (strength before crosslinking) of the rubber composition is greatly reduced, so that the rubber composition adheres to the mixer roll and the rubber is kneaded. There are problems such as remarkably impairing the properties and worsening the molding processability (such as the shape stability of the molded product) during extrusion. For example, a carbon oil high-filled rubber composition containing 90 parts by weight or more of carbon black and 50 parts by weight or more of oil with respect to 100 parts by weight of diene rubber generally has a problem that the green strength is greatly reduced. Therefore, Patent Document 1 describes blending polynorbornene rubber.

  On the other hand, Non-Patent Documents 1 and 2 describe that increasing the ethylene content and facilitating crystallization are effective in improving the green strength of ethylene / α-olefin / non-conjugated diene random copolymer (EPDM). Has been. However, increasing the ethylene content in EPDM causes deterioration of low temperature characteristics, and at the time of roll processing and extrusion molding, a high green strength is often required at a relatively high temperature (for example, 50 to 100 ° C.), In that case, the ethylene crystal component is melted, so that a sufficient green strength cannot be obtained.

JP-A-7-97485

New edition Rubber Technology Basics, P.123, Japan Rubber Association BANDO TECHNICAL REPORT NO.9 / 2005

  The present invention is intended to solve the problems associated with the prior art as described above, and by improving the green strength at high temperatures (50 to 100 ° C.), it has excellent handling properties and good molding. It is an object of the present invention to provide a rubber composition having processability and to provide a rubber molded article obtained from the rubber composition and having a good balance between mechanical properties and rubber elasticity.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that a blend of a specific polyolefin resin microdispersed in an ethylene / α-olefin / non-conjugated diene random copolymer and a filler. The rubber composition obtained by kneading the rubber composition contained at a temperature above the softening point of the polyolefin resin, then starting to apply shear at a temperature above the softening point of the polyolefin resin, and cooling to below the softening point while applying shear. The composition exhibits high green strength at high temperatures (50 to 100 ° C.), has excellent handling properties and good moldability during molding, and a rubber molded body obtained from the rubber composition is a machine. The present invention has been completed by finding that it has a good balance between mechanical properties and rubber elasticity. That is, the present invention includes the following matters.

(1) In 100 parts by weight of ethylene / α-olefin / non-conjugated diene random copolymer (A), 2 to 15 parts by weight of a polyolefin resin (B) having a melting point of 125 to 170 ° C. was microdispersed in a molten state. A rubber composition comprising 30 to 240 parts by weight of a resin and a filler.
(2) Melting and kneading a resin containing an ethylene / α-olefin / nonconjugated diene random copolymer (A) and a polyolefin resin (B) having a melting point of 125 to 170 ° C. at a temperature equal to or higher than the melting point of the polyolefin resin (B). Then, the first step of microdispersing the polyolefin resin (B) in the copolymer (A), a filler and, if necessary, additives are added, and the second kneading is performed at a temperature equal to or higher than the softening point of the polyolefin resin (B). (1) characterized by comprising a third step of starting to apply shear at a temperature equal to or higher than the softening point of the polyolefin resin (B) and then cooling to less than the softening point of the polyolefin resin (B) while applying shear. The manufacturing method of the rubber composition of description.

  The rubber composition of the present invention has excellent moldability by having a high green strength at a relatively high temperature (50 to 100 ° C.). By vulcanizing the rubber composition, excellent mechanical properties and A rubber molded body having both rubber elasticity can be obtained.

  Since the rubber molded body has a high green strength at a relatively high temperature (50 to 100 ° C.), an improvement in productivity due to an improvement in handling at the time of molding processing, a treatment for bending the molded unvulcanized rubber, etc. Since handling at the time of processing and reduction of product defects can be achieved, it can be suitably used as materials for automobile weather strips, grommets, and hoses, and for hoses.

Hereinafter, the rubber composition and the rubber molded body according to the present invention will be specifically described.
[Ethylene / α-olefin / non-conjugated polyene copolymer rubber (A)]
The ethylene / α-olefin / nonconjugated polyene copolymer rubber according to the present invention is derived from a unit derived from ethylene, a unit derived from an α-olefin having 3 or more, preferably 3 to 20 carbon atoms, and a nonconjugated polyene. A copolymer rubber containing units.

  Specific examples of the α-olefin include propylene, 1-butene, 4-methylpentene-1, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1 Dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-nonadecene, 1-eicocene, 9-methyldecene-1, 11-methyldodecene-1, 12-ethyltetradecene-1, etc. Is mentioned. Of these, propylene, 1-butene, 4-methylpentene-1, 1-hexene and 1-octene are preferable, and propylene is particularly preferable.

These α-olefins are used alone or in combination of two or more.
Specific examples of the non-conjugated polyene include 1,4-hexadiene, 3-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 4 Chain unconjugated such as 1,5-dimethyl-1,4-hexadiene, 7-methyl-1,6-octadiene, 8-methyl-4-ethylidene-1,7-nonadiene and 4-ethylidene-1,7-undecadiene Diene; methyltetrahydroindene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 5-vinylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2 Cyclic non-conjugated dienes such as -norbornene, 5-vinyl-2-norbornene, 5-isopropenyl-2-norbornene, 5-isobutenyl-2-norbornene, cyclopentadiene and norbornadiene; 2,3-diisopropylidene-5-norbornene 2-ethylidene-3-isopro Isopropylidene-5-norbornene, 2-propenyl-2,2-norbornadiene, etc. trienes and 4-ethylidene-8-methyl-1,7-nonadiene and the like. Of these, 5-ethylidene-2-norbornene and 5-vinyl-2-norbornene are preferable.
These non-conjugated polyenes are used alone or in combination of two or more.

  The ethylene / α-olefin / non-conjugated polyene copolymer rubber according to the present invention has a molar ratio of the structural unit derived from ethylene (a) and the structural unit derived from α-olefin (b) [(a) / (B)] is 50/50 to 90/10, preferably 85/15, and the weight percent of structural units derived from non-conjugated polyene (c) is 1.0 wt% to 20.0 wt%, preferably 3 It is contained in an amount of 0.0 wt% to 15 wt%, more preferably 3.0 wt% to 14 wt%.

  The ethylene / α-olefin copolymer rubber and the ethylene / α-olefin / non-conjugated polyene copolymer rubber according to the present invention usually have an intrinsic viscosity [η] measured in decalin of 135 ° C. It is 0-5.0 dl / g, Preferably it is 1.0-4.0 dl / g.

  Specific examples of the ethylene / α-olefin / non-conjugated polyene copolymer rubber according to the present invention include ethylene / propylene / 5-ethylidene-2-norbornene random copolymer, ethylene / propylene / 5-ethylidene-2-norbornene. -A 5-vinyl-2-norbornene random copolymer can be exemplified.

[Polyolefin resin (B)]
The polyolefin resin (B) contained in the rubber composition of the present invention can be used without particular limitation as long as it is a polyolefin resin having a melting point measured by a differential scanning calorimeter (DSC) in the range of 125 to 170 ° C. And polypropylene such as high density polyethylene (HDPE), propylene homopolymer, propylene block copolymer, propylene random copolymer;
1-butene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, etc., a crystalline homopolymer or copolymer of an α-olefin having 4 to 20 carbon atoms, preferably 4 to 8 carbon atoms Etc.

  The said melting | fusing point is 125-170 degreeC normally, Preferably it is 130-165 degreeC. Among these, HDPE and polypropylene are preferable, and polypropylene is particularly preferable.

  As polyolefin resin (B) used for this invention, what was manufactured by the conventionally well-known method may be used, and a commercial item may be used.

  In the copolymer composition of the present invention, the polyolefin resin (B) is usually 2 to 15 parts by weight, preferably 3 to 13 parts by weight per 100 parts by weight of the ethylene / α-olefin / non-conjugated polyene copolymer (A). Parts, more preferably 3 to 11 parts by weight. If the polyolefin resin (B) is used within this range, excellent processability and rubber properties can be maintained.

[Other resins]
The rubber composition may contain other resins, such as ethylene / α-olefin copolymer resins.
The ethylene / α-olefin copolymer resin is a copolymer resin containing a unit derived from ethylene and a unit derived from an α-olefin having 3 or more carbon atoms, preferably 3 to 20 carbon atoms.
Examples of the α-olefin include the above olefins.

[Filler]
The filler that is one of the components contained in the rubber composition of the present invention is not particularly limited as long as it is a filler that is usually used as a filler for synthetic rubber. Examples of such fillers include carbon black such as SRF, GPF, FEF, MAF, HAF, ISAF, SAF, FT, MT, silica, activated calcium carbonate, light calcium carbonate, heavy calcium carbonate, fine powder talc, fine powder silicic acid. , Talc, clay and the like, and those obtained by treating the surface of these inorganic substances with a silane coupling agent or the like can be used. Commercially available carbon blacks include “Asahi # 55G”, “Asahi # 50HG”, “Asahi # 60G” (trade name; manufactured by Asahi Carbon Co., Ltd.), “Seast V”, “Seast SO” (trade name; Tokai Carbon Co., Ltd.). The specific surface area of such a filler is preferably 5 to 120 m ² / g.

(Rubber composition)
The rubber composition of the present invention comprises 2 to 15 parts by weight of a polyolefin resin (B) having a melting point of 125 to 170 ° C. in 100 parts by weight of the ethylene / α-olefin / non-conjugated diene random copolymer (A), Preferably 3 to 13 parts by weight, more preferably 3 to 11 parts by weight of a resin microdispersed in a molten state and the filler 30 to 240 parts by weight, preferably 40 to 220 parts by weight, more preferably 50 to 200 parts by weight. In the range of parts.

  A rubber composition having a blending amount of the polyolefin resin (B) of less than 2 parts by weight may not obtain a desired green strength, and there is a possibility that handling properties and extrusion processability during molding processing may not be improved. On the other hand, the rubber composition in which the blending amount of the polyolefin resin (B) exceeds 15 parts by weight, the extrusion processability is remarkably deteriorated as the viscosity of the rubber composition increases, and the rubber molding obtained by vulcanization is obtained. There is a possibility that the rubber elasticity and the like of the body may be lowered.

  In a rubber composition having a filler content of less than 30 parts by weight, the molded product obtained by vulcanization may be inferior in rigidity and mechanical strength and may have a significantly increased production cost. On the other hand, a rubber composition in which the blending amount of the filler exceeds 240 parts by weight has poor kneading processability, and there is a risk that the rubber elasticity, mechanical strength, etc. of the rubber molded product obtained by vulcanization will be reduced.

[Crosslinking agent]
In the rubber composition of the present invention, a cross-linking agent is added to the ethylene / α-olefin / non-conjugated diene random copolymer (A) and a resin obtained by microdispersing the polyolefin resin (B) in a molten state and a filler. May be added. Examples of the crosslinking agent used for crosslinking include vulcanizing agents such as sulfur and sulfur compounds, and organic peroxides.

(Vulcanizing agent)
As one of the crosslinking agents, sulfur and sulfur compounds can be used as the vulcanizing agent used in vulcanization. Specific examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur, insoluble sulfur and the like.

  Specific examples of the sulfur compound include sulfur chloride, sulfur dichloride, and polymer polysulfide. Also use sulfur compounds that release active sulfur at the vulcanization temperature, such as morpholine disulfide, alkylphenol disulfide, tetramethylthiuram disulfide, dipentamethylenethiuram tetrasulfide, selenium dimethyldithiocarbamate. Can do. Of these, sulfur is preferably used. These sulfur and sulfur compounds are used alone or in combination of two or more.

  Sulfur and sulfur compounds are usually 0.1 to 10 parts by weight, preferably 0.3 to 5 parts by weight per 100 parts by weight of ethylene / α-olefin / non-conjugated diene random copolymer (A). Although it is used, it is desirable to appropriately determine the optimum amount according to the required physical properties. Moreover, when using sulfur and a sulfur compound as a vulcanizing agent, it is preferable to use a vulcanization accelerator together.

(Vulcanization accelerator)
Specific examples of the vulcanization accelerator include N-cyclohexyl-2-benzothiazole sulfenamide, N-oxydiethylene-2-benzothiazol sulfenamide, N, N-diisopropyl-2-benzothiazol sulfenamide. Sulfenamide compounds such as 2-mercaptobenzothiazole, 2- (2 ', 4'-dinitrophenyl) mercaptobenzothiazole, 2- (4'-morpholinodithio) benzothiazole, dibenzothiazyl disulfide Compound: Guanidine compound such as diphenylguanidine, diorthotolylguanidine, diorthonitrile guanidine, orthonitrile biguanide, diphenylguanidine phthalate; acetaldehyde-aniline reactant, butyraldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde Aldehyde amines such as ammonia or aldehyde-ammonia compounds; Imidazoline compounds such as 2-mercaptoimidazoline; Thiuram compounds such as monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, pentamethylenethiuram tetrasulfide; zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc di-n-butyldithiocarbamate, ethylphenyldithiocarbamine Zinc acid, zinc butylphenyl dithiocarbamate, sodium dimethyldithiocarbamate, dimethyldithio Selenium carbamic acid, dithio acid salt-based compounds such as dimethyl dithiocarbamate tellurium; xanthate-based compounds such as dibutyltin xanthate zinc; zinc white (zinc oxide) may include compounds such as.

  These vulcanization accelerators are usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin / non-conjugated diene random copolymer (A). Although used in proportions, it is desirable to determine the optimum amount as appropriate according to the required physical properties.

(Organic peroxide)
The organic peroxide that is one of the crosslinking agents may be any one that is usually used for peroxide vulcanization of rubber. Specifically, dicumyl peroxide, di-t-butyl peroxide, di-t-butylperoxy-3,3,5-trimethylcyclohexane, t-butyl hydroperoxide, t-butylcumyl peroxide, benzoyl Peroxide, 2,5-dimethyl-2,5-di (t-butylperoxin) hexyne-3, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2 , 5-mono (t-butylperoxy) -hexane, α, α'-bis (t-butylperoxy-m-isopropyl) benzene, and the like. Of these, dicumyl peroxide, di-t-butyl peroxide, and di-t-butylperoxy-3,3,5-trimethylcyclohexane are preferably used. These organic peroxides are used alone or in combination of two or more.

  The organic peroxide is usually 0.0003 to 0.05 mol, preferably 0.001 to 0.03 mol with respect to 100 g of the ethylene / α-olefin / non-conjugated diene random copolymer (A). Although it is used, it is desirable to determine the optimum amount as appropriate according to the required physical properties.

  When using an organic peroxide as a crosslinking agent, it is preferable to use a crosslinking aid in combination. Specific examples of the crosslinking aid include sulfur; quinone dioxime compounds such as p-quinone dioxime; methacrylate compounds such as polyethylene glycol dimethacrylate; allyl compounds such as diallyl phthalate and triallyl cyanurate; Maleimide compounds; divinylbenzene and the like. Such a crosslinking aid is used in an amount of 0.5 to 2 mol, preferably about equimolar, with respect to 1 mol of the organic peroxide used.

[Other ingredients]
In the rubber composition according to the present invention, the polyolefin resin (B) is melted in an ethylene / α-olefin / non-conjugated diene random copolymer (A) according to the intended use and performance of the vulcanizate. In addition to micro-dispersed resins and fillers, various known compounding agents generally used in the manufacture of rubber products, such as softeners, vulcanization aids, anti-aging agents, processing aids, alkoxysilane compounds, and crosslinking agents , Crosslinking aids, activators, reaction inhibitors, colorants, dispersants, flame retardants, plasticizers, antioxidants, scorch inhibitors, UV absorbers, antistatic agents, lubricants, fungicides, peptizers , Tackifiers, various dyes such as disperse dyes and acid dyes, inorganic and organic pigments, surfactants, compounding agents such as paints, and foaming agents such as foaming agents and foaming aids as necessary Compounds, defoamers for the purpose of the present invention Suitably selected within a range that does not impair, it can be formulated appropriate amount.

(Softener)
As the softener, a softener usually used for rubber can be used.
Specifically, petroleum-based softeners such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt, and petroleum jelly; coal-tar softeners such as coal tar and coal tar pitch; castor oil, linseed oil, rapeseed oil, Fat oil-based softeners such as coconut oil; tall oil; sub; waxes such as beeswax, carnauba wax and lanolin; fatty acids and fatty acid salts such as ricinoleic acid, palmitic acid, barium stearate, calcium stearate and zinc laurate; petroleum Examples thereof include synthetic polymer materials such as resin, atactic polypropylene, and coumarone indene resin. Of these, petroleum softeners are preferably used, and process oil is particularly preferably used.

  The amount of these softeners can be appropriately selected depending on the use of the rubber molded body, but is usually 150 parts by weight or less with respect to 100 parts by weight of the ethylene / α-olefin / non-conjugated diene random copolymer (A), The maximum is preferably 130 parts by weight or less.

(Anti-aging agent)
If an anti-aging agent is used, the material life can be further extended. This is the same as in the case of ordinary rubber.

  Specific examples of the antioxidant used in the present invention include phenylnaphthylamine, 4,4 ′-(α, α-dimethylbenzyl) diphenylamine, N, N′-di-2-naphthyl-p-phenylenediamine, and the like. Aromatic secondary amine stabilizers: 2,6-di-t-butyl-4-methylphenol, tetrakis- [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl ) Propionate] phenol stabilizers such as methane; thioether stabilizers such as bis [2-methyl-4- (3-n-alkylthiopropionyloxy) -5-t-butylphenyl] sulfide; 2-mercaptobenzimidazole, etc. Benzoimidazole stabilizers; dithiocarbamate stabilizers such as nickel dibutyldithiocarbamate; quinoline stabilizers such as a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline. These anti-aging agents are used alone or in combination of two or more.

  Such an anti-aging agent is usually used in a proportion of 5 parts by weight or less, preferably 3 parts by weight or less, based on 100 parts by weight of the ethylene / α-olefin / non-conjugated diene random copolymer (A). It is desirable to determine the optimum amount as appropriate according to the required physical property value.

(Processing aid)
As the processing aid, a compound used for processing ordinary rubber can be used. Specifically, higher fatty acids such as ricinoleic acid, stearic acid, palmitic acid and lauric acid, higher fatty acid salts such as barium stearate, zinc stearate and calcium stearate, ricinoleic acid ester, stearic acid ester, palmitic acid ester and lauric acid And higher fatty acid esters such as acid esters.

  Such a processing aid is usually used in a proportion of 10 parts by weight or less, preferably 5 parts by weight or less, based on 100 parts by weight of the ethylene / α-olefin / non-conjugated diene random copolymer (A). It is desirable to determine the optimum amount as appropriate according to the required physical property value.

(Foaming agent and foaming aid)
The rubber molded body according to the present invention, which will be described later, is blended with a foaming agent and a foaming auxiliary agent that are usually used for rubber in the rubber composition according to the present invention as necessary, and is molded, foamed, and vulcanized. It can also be obtained.

  Specific examples of the blowing agent include inorganic blowing agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, and ammonium nitrite; N, N'-dimethyl-N, N'-dinitrosotephthalamide, N Nitroso compounds such as, N'-dinitrosopentamethylenetetramine; Azo compounds such as azodicarbonamide, azobisisobutyronitrile, azocyclohexylnitrile, azodiaminobenzene, barium azodicarboxylate; benzenesulfonyl hydrazide, toluenesulfonyl hydrazide , Sulfonyl hydrazide compounds such as p, p'-oxybis (benzenesulfonylhydrazide), diphenylsulfone-3,3'-disulfonylhydrazide; calcium azide, 4,4-diphenyldisulfonyl azide, p-toluenesulfuronyl azide, etc. The azide compound of It is below.

  These foaming agents are used in a proportion of 0.5 to 30 parts by weight, preferably 1 to 20 parts by weight, based on 100 parts by weight of the ethylene / α-olefin / non-conjugated diene random copolymer (A). If necessary, the foaming aid used in combination with the foaming agent acts to lower the decomposition temperature of the foaming agent, promote decomposition, and make the bubbles uniform. Examples of such foaming aids include organic acids such as salicylic acid, phthalic acid, stearic acid, and oxalic acid, urea, and derivatives thereof.

  These foaming assistants are 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the ethylene / α-olefin / non-conjugated diene random copolymer (A). Although it is used, it is desirable to appropriately determine the optimum amount according to the required physical property value.

(Defoamer)
When the compounded rubber is vulcanized, bubbles may be formed or the degree of foaming may be different depending on the moisture contained. In order to prevent these, calcium oxide may be added as a defoaming agent.

  The defoaming agent is usually used in a proportion of 20 parts by weight or less, preferably 10 parts by weight or less, based on 100 parts by weight of the ethylene / α-olefin / non-conjugated diene random copolymer (A), but is required. It is desirable to determine the optimum amount as appropriate according to the physical property value.

[Method for producing rubber composition]
The rubber composition according to the present invention is a resin in which a polyolefin resin (B) having a melting point of 125 to 170 ° C. is microdispersed in a molten state in an ethylene / α-olefin / non-conjugated diene random copolymer (A). In addition to the filler, for example, it can be prepared from various known compounding agents generally used in the manufacture of rubber products, such as softeners and crosslinking agents, by a general method for producing rubber compounds.

  As a method for producing a rubber composition, first, an ethylene / α-olefin / non-conjugated diene random copolymer (A) and a polyolefin resin (B), which are essential components of the present invention, are mixed with, for example, a twin-screw extruder or Banbury. Micro-dispersion of polyolefin resin (B) in molten state in ethylene / α-olefin / non-conjugated diene random copolymer (A) using internal mixers (closed mixers) such as mixers, kneaders and intermixes Prepare the resin. Next, fillers, if necessary, additives such as softeners (for oil expansion), processing aids, vulcanization accelerators, internal mixers (closed mixers) such as Banbury mixers, kneaders and intermixes Depending on the type, the mixture is kneaded for 2 to 20 minutes at a temperature of 80 to 170 ° C. (a temperature higher than the softening point of the polyolefin resin). Next, using a roll such as an open roll or a kneader, the composition starts to be sheared at a temperature equal to or higher than the softening point of the polyolefin resin (B), and while applying the shear, the polyolefin resin (B) Cool to below softening point. Then, the resulting blend is added with a softening agent, a vulcanizing agent (for example, sulfur), a vulcanization accelerator, and, if necessary, an additive such as a foaming agent or a crosslinking agent. By adding a vulcanization accelerator, a crosslinking aid, a foaming aid, and a desiccant as necessary using a kneader, kneading at a roll temperature of 40 to 80 ° C. for 5 to 30 minutes, and then dispensing. Can be prepared.

[Rubber molded body and method for producing the same]
(Rubber molded product)
The rubber molded body of the present invention is formed by vulcanizing the rubber composition of the present invention, and is formed by microdispersing the polyolefin resin, and thus has both excellent mechanical properties and rubber elasticity. Therefore, it can be applied to various uses such as automobile parts, home appliance related parts, civil engineering / building material related parts, miscellaneous goods, and daily necessities, which are normal uses of ethylene / α-olefin / non-conjugated diene random copolymers. Examples of such applications include automotive weather strips such as door weather strips, trunk weather strips, luggage weather strips, roof side rail weather strips, sliding door weather strips, ventilator weather strips, sliding loop panel weather strips. , Front window weather strip, rear window weather strip, quarter window weather strip, lock pillar weather strip, door glass outer weather strip, door glass inner weather strip, dam windshield, glass run channel, bracket for door mirror, seal headlamp, seal Cowl top; automotive hoses such as brake hoses, radiators -Hose, heater hose, air cleaner hose; water supply hose; gas hose; building material seal parts such as gaskets, air tights, joint materials, door stops; home appliance seal parts; automotive cup seal materials such as master cylinder piston cups And wheel cylinder piston cups.

  The rubber molded body of the present invention may be a foam molded body as long as it does not impair the physical properties.

  Specific examples of the foamed molded product include door sponge sponges, opening trim sponges, food seal sponges, trunk seal sponges, and other weather strip sponge materials; heat-insulating sponges, dam rubber and other highly foamed sponge materials. .

(Method for producing rubber molded body)
In order to produce a rubber molded body from the rubber composition according to the present invention, an unvulcanized compounded rubber is prepared once by the method described above, as in the case of vulcanizing ordinary rubber, Vulcanization may be performed after the compounded rubber is formed into the intended shape.

  The unvulcanized rubber composition prepared as described above can be molded and vulcanized by various molding methods, but can be molded and vulcanized by molding such as compression molding, extrusion molding and injection molding. The characteristics can be exhibited most when vulcanizing.

  That is, in the case of compression molding, a pre-weighed unvulcanized compounded rubber composition is put into a mold, and after closing the mold, heated at a temperature of 120 to 270 ° C. for 30 seconds to 120 minutes. A vulcanized rubber molding is obtained.

  In the case of extrusion molding, the compounded rubber composition in the form of a ribbon or pellets is supplied to an extruder in which a die having a desired shape is set. Next, the rubber composition prepared in a desired shape is continuously supplied into a vulcanization tank set at a temperature of 150 ° C. to 350 ° C., and heated for 30 seconds to 20 minutes, whereby the desired rubber molded body is obtained. Is obtained.

  In the case of injection molding, a ribbon-like or pellet-like compounded rubber composition is supplied to the pot by a preset amount with a screw. Subsequently, the preheated compounded rubber is fed into the mold by a plunger in 1 to 20 seconds. After injecting the compounded rubber, the target rubber molded body is obtained by heating at a temperature of 120 to 270 ° C. for 30 seconds to 120 minutes.

  EXAMPLES Next, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited by these.

In the examples and comparative examples, the following was used.
(I): Ethylene / propylene / 5-ethylidene-2-norbornene terpolymer (trade name: Mitsui EPT3090E (trademark), manufactured by Mitsui Chemicals, Inc., ethylene content 58 wt%, oil extended amount 10 parts by weight)
(Ii): Ethylene / propylene / 5-ethylidene-2-norbornene terpolymer (trade name: Mitsui EPT3062E (trademark), manufactured by Mitsui Chemicals, Inc., ethylene content 69 wt%, oil extended amount 20 parts by weight)
(Iii): high density polyethylene (HDPE) [trade name: HI-ZEX 2200J (trade mark) Corporation manufactured by Prime Polymer Co., density 964Kg / m ^3, melting point 135 ° C., a Vicat softening point 130 ° C.]
(Iv): Propylene homopolymer [trade name: Prime Polypro J105G (trademark) manufactured by Prime Polymer Co., Ltd., melting point 162 ° C., Vicat softening point 149 ° C., density 900 kg / m ³ ]
(V): Propylene random copolymer [Brand name: Prime Polypro J226FT (trademark) manufactured by Prime Polymer Co., Ltd., melting point 146 ° C., Vicat softening point 133 ° C., density 910 kg / m ³ ]
(Vi): Low-density polyethylene [trade name: Mirason 9 (trademark) manufactured by Mitsui DuPont Polychemical Co., Ltd., melting point 110 ° C., Vicat softening point 95 ° C., density 921 kg / m ³ , melting point 110 ° C.]
[Melting point and Vicat softening point]
The melting point was measured according to JIS K-7121, and the Vicat softening point was measured according to JIS K-7206.

[Minimum viscosity (Vm) and scorch time (t5)]
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 the time from when the minimum viscosity Vm is increased by 5 points is measured. This was determined as the scorch time (min.).

[Green strength (maximum stress value)]
The unvulcanized rubber composition was pressed at 100 ° C. for 5 minutes to form a sheet having a thickness of 2 mm, punched with a dumbbell-shaped JIS No. 3 test piece, and 100 mm / min under each atmosphere of 23 ° C., 50 ° C., and 100 ° C. . A tensile test was conducted at a tensile speed of and a maximum stress value (yield point modulus) was measured.

[Tensile test]
The vulcanized molded body was subjected to a tensile test according to JIS K6251 under the conditions of a measurement temperature of 23 ° C. and a tensile speed of 500 mm / min, and the strength at break (TB) and elongation at break (EB) were measured.

[Hardness test]
The flat portion of the vulcanized molded body was overlapped to 12 mm, and the hardness (JIS-A) was measured according to JIS K6253.

[Compression set test]
A sample was extracted from the vulcanized molded article in accordance with JIS K6250 6.5, and the compression set after treatment at 125 ° C. × 24 hours and −25 ° C. × 24 hours was measured according to JIS K6262 (1997).

[Reference Example 1]
The rubber composition before vulcanization in the rubber composition was ethylene / propylene / 5-ethylidene-2 using MIXTRON BB MIXER (manufactured by Kobe Steel, BB-4 type, volume 2.95 L, rotor 4WH). -Norbornene terpolymer [trade name: Mitsui EPT3090E, manufactured by Mitsui Chemicals, oil extension: 10 parts by weight] 110 parts by weight (EPT content: 100 parts by weight) (A), vulcanization acceleration 5 parts by weight of zinc oxide (trade name; 2 types of zinc oxide, manufactured by Hakusuitec Co., Ltd.) as auxiliary agents, 1 part by weight of stearic acid and PEG # 4000 as processing aids, and "Asahi # 60G" as filler (Trade name: manufactured by Asahi Carbon Co., Ltd.) 125 parts by weight, “Whiteon SB” (trade name: manufactured by Shiraishi Calcium Co., Ltd.) 30 parts by weight, Oil PS-430 "; and (trade name manufactured by Idemitsu Kosan Co., Ltd.) 75 parts by weight of kneading. The kneading conditions were such that the rotor rotation speed was 50 rpm, the floating weight pressure was 3 kg / cm ² , the kneading time was 5 minutes, and the kneading discharge temperature was 157 ° C.

  Next, after confirming that the temperature of the blend became 40 ° C., “Sunseller TT” (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 BZ” (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.) as a vulcanization accelerator, 1.8 parts by weight, and “Sunseller 22-C” (trade name; 0.5 parts by weight of Shin Kagaku Kogyo Co., Ltd., 1.5 parts by weight of “Sanfell R” (trade name; manufactured by Sanshin Chemical Co., Ltd.) as a vulcanization accelerator, and 0 sulfur as a vulcanizing agent Kneaded 5 parts by weight. 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. This blend was pressed at 100 ° C. for 5 minutes using a press molding machine to form a sheet having a thickness of 2 mm, and the green strength was measured. Next, the compound was vulcanized at 170 ° C. for 10 minutes using a press molding machine to prepare a rubber sheet having a thickness of 2 mm. A rubber block for compression set test was prepared by vulcanization at 170 ° C. for 15 minutes.

  About the obtained vulcanizate, the unvulcanized physical property, the tensile test, the hardness test, and the compression set test were performed by the above method. The results are shown in Table 1.

[Reference Example 2]
In Reference Example 1, the ethylene / propylene / 5-ethylidene-2-norbornene terpolymer (A) was changed from (i) 3090E to (ii) 3062E, and the softener “Diana Process Oil PS- 430 "trade name; manufactured by Idemitsu Kosan Co., Ltd.) was performed in the same manner as in Reference Example 1 except that the amount added was changed from 75 parts by weight to 65 parts by weight. The results are shown in Table 1.

[Example 1]
Ethylene / propylene / 5-ethylidene-2-norbornene terpolymer [trade name: Mitsui EPT3090E, manufactured by Mitsui Chemicals, oil extended amount: 10 parts by weight] 110 parts by weight (EPT content: 100 parts by weight) ( a), and high density polyethylene (HDPE) [trade name: HI-ZEX 2200J (trade mark) Corporation manufactured by Prime polymer Co., density 964Kg / m ^3, melting point 135 ° C., a Vicat softening point 130 ° C.] (B) 6 parts by weight, The mixture was placed in MIXTRON BB MIXER (Kobe Steel Works, BB-4 type, volume 2.95 L, rotor 4WH) and kneaded at about 165 ° C. for 5 minutes to uniformly disperse HDPE in Mitsui EPT3090E. Then, it discharged from the mixer and cooled naturally. For the resin composition, 5 parts by weight of 2 types of zinc oxide (trade name; 2 types of zinc oxide, manufactured by Hakusuitec Co., Ltd.) as a vulcanization acceleration aid, and 1 each of stearic acid and PEG # 4000 as processing aids. 119 parts by weight of “Asahi # 60G” (trade name; manufactured by Asahi Carbon Co., Ltd.), 30 parts by weight of “Whiteon SB” (trade name: manufactured by Shiraishi Calcium Co., Ltd.), and “ 75 parts by weight of Diana Process Oil PS-430 (trade name; manufactured by Idemitsu Kosan Co., Ltd.) 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 162 ° C. Next, the compounded rubber composition began to be sheared using a 14-inch roll while being at 162 ° C., and was cooled while being sheared. As a result, the temperature of the rubber composition was 70 ° C. 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 5 minutes.

  Next, after confirming that the temperature of the blend became 40 ° C., “Sunseller TT” (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 BZ” (trade name; manufactured by Sanshin Chemical Industry Co., Ltd.) as a vulcanization accelerator, 1.8 parts by weight, and “Sunseller 22-C” (trade name; 0.5 parts by weight of Shin Kagaku Kogyo Co., Ltd., 1.5 parts by weight of “Sanfell R” (trade name; manufactured by Sanshin Chemical Co., Ltd.) as a vulcanization accelerator, and 0 sulfur as a vulcanizing agent Kneaded 5 parts by weight. 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. This blend was pressed at 100 ° C. for 5 minutes to form a 2 mm thick sheet, and the green strength was measured.

  Next, the compound was vulcanized at 170 ° C. for 10 minutes using a press molding machine to prepare a rubber sheet having a thickness of 2 mm. Also. A rubber block for compression set test was prepared by vulcanization at 170 ° C. for 15 minutes.

  About the obtained vulcanizate, the unvulcanized physical property, the tensile test, the hardness test, and the compression set test were performed by the above method. The results are shown in Table 1.

[Example 2]
In Example 1, as the polyolefin resin (B) component, (iv) propylene homopolymer [trade name: Prime Polypro J105G (trademark) manufactured by Prime Polymer Co., Ltd., density 900 kg / m ³ , melting point 162 ° C., Vicat softening point 149 ° C. ] Was changed to 3 parts by weight, and “Asahi # 60G” in the filler was changed to 122 parts by weight. At that time, the temperature at which the ethylene / propylene / 5-ethylidene-2-norbornene terpolymer and the propylene homopolymer were kneaded was 185 ° C. The compounded rubber composition began to be sheared using a 14-inch roll at 165 ° C., and was cooled while being sheared. As a result, the temperature of the rubber composition was 70 ° C. The results are shown in Table 1.

Example 3
In Example 2, it carried out similarly to Example 2 except having changed the compounding quantity of the polyolefin resin (B) component into 6 weight part and changing "Asahi # 60G" in a filler into 119 weight part. The results are shown in Table 1.

Example 4
In Example 2, it carried out like Example 2 except having changed the compounding quantity of polyolefin resin (B) component into 9 weight part, and changing "Asahi # 60G" in a filler into 116 weight part. The results are shown in Table 1.

Example 5
In Example 1, as the polyolefin resin (B) component ((v): propylene random copolymer [trade name: Prime Polypro J226FT trademark] manufactured by Prime Polymer Co., Ltd., density 910 kg / m ³ , melting point 146 ° C., Vicat softening Point 133 ° C.] The procedure was the same as Example 1 except that the change was made. At that time, the temperature at which the ethylene / propylene / 5-ethylidene-2-norbornene terpolymer and the propylene homopolymer were kneaded was 170 ° C. Further, the compounded rubber composition began to be sheared at 161 ° C. using a 14-inch roll and was cooled while being sheared. As a result, the temperature of the rubber composition was 70 ° C. The results are shown in Table 1.

[Comparative Example 1]
In Example 2, it carried out like Example 2 except having changed the compounding quantity of polyolefin resin (B) component into 20 weight part, and changing "Asahi # 60G" in a filler into 105 weight part. The results are shown in Table 1.

[Comparative Example 2]
In Example 1, the component (B) of polyolefin resin was (vi): low density polyethylene [trade name: Milason 9 (trademark), Mitsui / DuPont Polychemical Co., Ltd., density 921 kg / m ³ , melting point 110 ° C., Vicat softening point 95 The procedure was the same as Example 1 except that the temperature was changed to [° C.]. At that time, the temperature at which the ethylene / propylene / 5-ethylidene-2-norbornene terpolymer and the propylene homopolymer were kneaded was 155 ° C. Further, the compounded rubber composition began to be sheared using a 14-inch roll at 155 ° C. and cooled while being sheared. As a result, the temperature of the rubber composition was 70 ° C. The results are shown in Table 1.

[Comparative Example 3]
In Comparative Example 2, the same procedure was performed as in Comparative Example 2, except that the amount of the polyolefin resin (B) component was 20 parts by weight and “Asahi # 60G” in the filler was changed to 105 parts by weight. The results are shown in Table 1.

[Comparative Example 4]
In Example 3, the compounded rubber composition prepared by kneading was naturally cooled to 50 ° C., and the shearing was started using a 14-inch roll at a temperature of 50 ° C. The same procedure as in Example 3 was performed except that the temperature of the rubber composition was 70 ° C. The results are shown in Table 1.

  The rubber molded body of the present invention is obtained by vulcanizing a rubber composition that exhibits high green strength at a relatively high temperature (50 to 100 ° C.) and has excellent moldability, and has excellent mechanical properties and rubber elasticity. Have both. Therefore, it is possible to improve productivity due to improved handling during molding, reduce handling defects during processing such as bending the molded unvulcanized rubber, and reduce weather defects such as automotive weather strips and grommets. This material can be suitably used as a material for hose.

Claims (10)

  Filled with 100 parts by weight of ethylene / α-olefin / non-conjugated diene random copolymer (A) with a resin in which 2 to 15 parts by weight of a polyolefin resin (B) having a melting point of 125 to 170 ° C. is microdispersed in a molten state. A rubber composition comprising 30 to 240 parts by weight of an agent.   The rubber composition according to claim 1, wherein the polyolefin resin (B) is contained in an amount of 2 to 11 parts by weight.   The rubber composition according to claim 1 or 2, further comprising a plasticizer.   The rubber composition according to any one of claims 1 to 3, further comprising a crosslinking agent.   A rubber molded article obtained by crosslinking the rubber composition according to claim 4.   The weather strip for motor vehicles obtained using the rubber composition as described in any one of Claims 1-4.   The grommet obtained using the rubber composition as described in any one of Claims 1-4.   The hose obtained using the rubber composition as described in any one of Claims 1-4.   The sealing material obtained using the rubber composition as described in any one of Claims 1-4.   A resin composition comprising an ethylene / α-olefin / non-conjugated diene random copolymer (A) and a polyolefin resin (B) having a melting point of 125 to 170 ° C. is melt-kneaded at a temperature equal to or higher than the melting point of the polyolefin resin (B). , The first step of microdispersing the polyolefin resin (B), the second step of kneading at a temperature above the softening point of the polyolefin resin (B) by adding a filler and additives as necessary, and subsequently the polyolefin resin (B) The method for producing a rubber composition according to claim 1, further comprising a third step of starting to apply shear at a temperature equal to or higher than the softening point, and cooling to a temperature lower than or equal to the softening point of the polyolefin resin (B) while applying shear.