JP2000290445A - ETHYLENE-alpha-OLEFIN-NONCONJUGATED DIENE COPOLYMER RUBBER COMPOSITION - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject rubber composition highly expandable when expanded, excellent in processability, capable of suppressing 'gel' formation, in particular when subjected to knead processing and extrusion processing operations, also excellent in the shape retention and compression set, etc., in crosslinking and expansion when highly expanded, and excellent in surface texture of the molded form therefrom as well. SOLUTION: This rubber composition is obtained by compounding (A) 100 pts.wt. of an ethylene-α-olefin-nonconjugated diene copolymer rubber with (B) polytetrafluoroethylene-contg. mixed powder comprising (a) polytetrafluoroethylene particles each <=10 μm in size and (b) an organic polymer so that the polytetrafluoroethylene component stands at 0.0001-20 pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ethylene which has a high foaming property at the time of foaming, is excellent in workability, shape retention, compression set, etc., and is suitable for a wide range of uses including sealing materials for automobiles, particularly, sponge rubber. -Α-olefin-non-conjugated diene copolymer rubber composition.

[0002]

2. Description of the Related Art An ethylene-α-olefin-non-conjugated diene copolymer rubber composition is excellent in various properties such as heat resistance, ozone resistance and weather resistance. However, sponge rubber composed of ethylene-α-olefin-non-conjugated diene copolymer rubber has been required to have a high level of performance as the performance of automobiles has been improved. I have. For example, noise such as engine noise generated at the time of high-speed driving of a car, wind noise around a door, and the like, such as leakage into a room and rain leakage, largely depend on the sealing performance of sponge rubber around a door. Sponge rubber requires extremely high sealing performance. Also,
When a car door is closed, the sponge rubber is left in a compressed state for a long period of time. Therefore, it is important to reduce the "set" (generally represented by compression set as an index) due to compression. ing. Therefore, the demands for the sealing performance and low "sag" of sponge rubber are as follows:
It is becoming increasingly demanding. In recent years, since the cross-sectional shape of sponge rubber for automotive sealing materials has become more complicated, when sponge rubber is manufactured by the usual continuous cross-linking method, the sponge deforms due to its own weight before completion of cross-linking and foaming. As a result, there is a problem that the desired shape cannot be maintained. Therefore, a sponge rubber having excellent shape retention as an index of the shape collapse is required. Further, in order to respond to the demand for cost reduction of sponge rubber, sponge rubber is highly foamed, that is, while having a small foaming specific gravity, it has excellent overall characteristics including the sealing performance, low “set” property, shape retention property and the like. There is a new demand for sponge rubber. Furthermore, in addition to the above-mentioned various properties, it is excellent in workability such as kneading workability, roll workability, extruding workability, etc. In particular, the "gel" due to shear strain and heat history at the time of kneading work and extrusion work is removed. It is necessary that the sponge is not easily formed, and that the sponge surface is good, in order to reduce poor appearance of the product. Under such circumstances, various ethylene-α-olefin-non-conjugated diene copolymer rubber compositions having a bimodal molecular weight distribution composed of a low molecular weight component and a high molecular weight component have been proposed. However, in such a rubber composition, the number of factors that have a significant effect on the properties of the composition and the sponge rubber obtained therefrom is large, and these factors are complicatedly correlated. In fact, it is extremely difficult to select and combine. For example, JP-A-61-278540 discloses that the ethylene / α-olefin weight ratio is 40/60 to 40/60.
70/30, a rubber composition having a low molecular weight component content of 5 to 50% by weight and a Mooney viscosity (ML1 + 8, 120 ° C.) of 50 to 110 is disclosed. In terms of processability, general roll processability and extrusion processability are good, but they are not satisfactory particularly from the viewpoint of suppression of "gel" generation. JP-A-4-80245 discloses that the ethylene / α-olefin weight ratio is 40/60 to 73/27, the iodine value is 10 to 36, and the weight ratio between the low molecular weight component and the high molecular weight component is 51/60. 49-80 / 20, a rubber composition having a low molecular weight component and a high molecular weight component having an iodine value ratio of 1.1 / 1 to 4/1 and a Mooney viscosity (ML1 + 4 at 121 ° C.) of 50 to 100. Although the composition has good extrusion processability and shape retention, it is difficult to achieve a high degree of foaming, and the composition is not sufficient in sponge physical properties. Further, Japanese Patent Publication No. 2-62582 discloses ethylene, α-olefin, 5-ethylidene-2-norbornene (ENB) and 5-vinyl-2-norbornene (VNB),
ENB / VNB molar ratio of 1/1 to 20/1, ENB and V
The total content of NB is 2 to 40 in terms of elementary value like a copolymer, and a copolymer rubber having a specific molecular weight and a molecular weight distribution is disclosed. A sponge rubber with a smooth surface can be obtained, but it has the disadvantage that the compression set is large when highly foamed, and that a "gel" is easily generated during kneading or extrusion. That is, the conventional rubber composition for sponge has a high foaming property, and further has a problem of comprehensively improving kneading processability, extrusion processability, shape retention during crosslinking / foaming, compression set, and the like. , Still unresolved.

[0003] JP-A-2-235943 discloses that a polyolefin resin such as an ethylene-α-olefin-non-conjugated diene copolymer rubber is used in combination with a pyrolytic foaming agent and a fluorine resin such as polytetrafluoroethylene. Discloses an attempt to improve processability by blending the compound. However, polytetrafluoroethylene has poor dispersibility with respect to a general thermoplastic resin containing no halogen atom, and this method requires a large amount of polytetrafluoroethylene to improve processability, There is a disadvantage that the surface properties of the molded article are impaired.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to have a high foaming property at the time of foaming and to be excellent in workability. In particular, it is possible to suppress the formation of "gel" at the time of kneading and extrusion, and to obtain a high foaming property. In this case, it is an object of the present invention to provide an ethylene-α-olefin-non-conjugated diene copolymer rubber composition which is excellent in shape retention at the time of crosslinking / foaming, excellent in compression set, etc., and also excellent in surface properties of a molded article. .

[0005]

The gist of the present invention is to provide an ethylene-α-olefin-non-conjugated diene copolymer rubber (A) 1
Polytetrafluoroethylene-containing mixed powder (B) composed of polytetrafluoroethylene particles (a) having a particle diameter of 10 μm or less and organic polymer (b) with respect to 00 parts by weight
However, the polytetrafluoroethylene component is 0.0001 to
In the ethylene-α-olefin-non-conjugated diene copolymer rubber composition blended to be 20 parts by weight.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The ethylene-α-olefin-non-conjugated diene copolymer rubber (A) used in the present invention. )
Consists of an ethylene-α-olefin-non-conjugated diene copolymer.

The α-olefin in the ethylene-α-olefin-non-conjugated diene copolymer is, for example, an α-olefin having 3 to 12 carbon atoms, specifically, propylene,
Butene-1,3-methylbutene-1, pentene-1,3
-Methylpentene-1,4-methylpentene-1,3-
Examples thereof include ethylpentene-1, hexene-1, octene-1, decene-1, and dodecene-1, and propylene is particularly preferred. These α-olefins can be used alone or in combination of two or more.

The non-conjugated diene in the ethylene-α-olefin-non-conjugated diene copolymer includes ethylidene norbornene, dicyclopentadiene, etc., with ethylidene norbornene being particularly preferred. When the non-conjugated diene in the ethylene-α-olefin-non-conjugated diene copolymer is dicyclopentadiene alone, the balance between the crosslinkability and the foaming property of the composition is lost, and a high foaming degree and a soft sponge rubber are obtained. This can be difficult.

The ethylene / α-olefin weight ratio in the ethylene-α-olefin-non-conjugated diene copolymer rubber (A) is 30/70 to 80/20, preferably 4/70.
0/60 to 70/30. In this case, ethylene / α
When the olefin weight ratio is less than 30/70, the dispersion of the filler in the composition becomes insufficient, and the sponge surface skin is damaged, and the strength of the sponge rubber is also reduced.
If it exceeds 20, the fluidity decreases and a large amount of energy is required at the time of kneading. In addition, the material rubber does not bite sufficiently into the roll or the extruder during processing, which causes a problem in processability. The heat resistance of rubber also decreases.

The ethylene-α- used in the present invention
The olefin-nonconjugated diene copolymer is prepared by a usual polymerization method using a medium / low pressure method, for example, a Ziegler-Natta catalyst comprising a transition metal compound and an organometallic compound in a suitable solvent, for example, at least one kind of solvent-soluble vanadium. Ethylene and an α-olefin in the presence of a catalyst comprising the compound and at least one organoaluminum compound;
A non-conjugated diene containing ethylidene norbornene as an essential component can be produced by a method of polymerizing while supplying hydrogen as a molecular weight regulator as required. The polymerization at that time can be carried out by a gas phase method (fluidized bed or stirred bed) or a liquid phase method (slurry method or solution method).

[0011] The solvent-soluble vanadium compound includes at least one of VOCl3, VCl4, VOCl3 or VCl4.
The reaction product of the species and the alcohol is preferred. in this case,
Examples of the alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, t-butanol, n-hexanol, n-octanol, 2-ethylhexanol, n-decanol, n-dodecanol and the like. Alcohols having 3 to 8 carbon atoms are particularly preferable.

The organic aluminum compounds include, for example, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, diethylaluminum monochloride, diisobutylaluminum monochloride, ethylaluminum sesquichloride,
Butylaluminum sesquichloride, ethylaluminum dichloride, butylaluminum dichloride, methylaluminoxane which is a reaction product of trimethylaluminum and water, and the like.Especially, ethylaluminum sesquichloride, butylaluminum sesquichloride, ethylaluminum sesquichloride and Mixtures with isobutylaluminum and mixtures of triisobutylaluminum and butylaluminum sesquichloride are preferred.

As the solvent, a hydrocarbon solvent is usually used, and preferred hydrocarbon solvents are n-pentane, n-hexane, n-heptane, n-octane, isooctane, cyclohexane and the like. These hydrocarbon solvents can be used alone or in combination of two or more.

The polytetrafluoroethylene-containing mixed powder (B) used in the present invention comprises polytetrafluoroethylene particles (a) having a particle diameter of 10 μm or less and an organic polymer (b). 10 tetrafluoroethylene
It is necessary that the aggregates have a size of not more than μm. As such a polytetrafluoroethylene-containing mixed powder, an aqueous dispersion of polytetrafluoroethylene particles (a) having a particle diameter of 0.05 to 1.0 μm and an organic polymer (b)
What is obtained by mixing with an aqueous dispersion of particles and pulverizing by coagulation or spray drying, or a particle diameter of 0.0
5 to 1.0 μm polytetrafluoroethylene particles (a) obtained by polymerizing the monomers constituting the organic polymer (b) in the presence of an aqueous dispersion, and then coagulating or spray-drying to obtain a powder. Or particle size 0.05 to
A monomer having an ethylenically unsaturated bond was emulsion-polymerized in a dispersion obtained by mixing an aqueous dispersion of 1.0 μm polytetrafluoroethylene particles (a) and an aqueous dispersion of organic polymer (b) particles. Thereafter, those obtained by pulverization by coagulation or spray drying are preferable. The aqueous dispersion of polytetrafluoroethylene particles (a) having a particle diameter of 0.05 to 1.0 μm used for obtaining the polytetrafluoroethylene-containing mixed powder (B) used in the present invention uses a fluorinated surfactant. It is obtained by polymerizing a tetrafluoroethylene monomer by emulsion polymerization.

In the emulsion polymerization of the polytetrafluoroethylene particles (a), hexafluoropropylene, chlorotrifluoroethylene, fluoroalkylethylene, perfluoroalkylvinyl ether may be used as a copolymer component as long as the properties of polytetrafluoroethylene are not impaired. Such as fluorinated olefins and perfluoroalkyl (meth)
Fluorine-containing alkyl (meth) acrylate such as acrylate can be used. The content of the copolymer component is preferably 10% by weight or less based on tetrafluoroethylene.

Commercially available raw materials for the dispersion of polytetrafluoroethylene particles (a) include Fluon AD-1, AD-936 manufactured by Asahi Glass Fluoropolymer Co., Ltd., and Polyflon D-1, D-2 manufactured by Daikin Industries, and DuPont Mitsui. A typical example is Teflon 30J manufactured by Fluorochemicals.

Although the organic polymer (b) constituting the polytetrafluoroethylene-containing mixed powder used in the present invention is not particularly limited, it is compounded with an ethylene-α-olefin-nonconjugated diene copolymer rubber. From the viewpoint of dispersibility at the time of the formation, it is preferable that the rubber has a high affinity with the ethylene-α-olefin-nonconjugated diene copolymer rubber.

Specific examples of the monomer for producing the organic polymer (b) include styrene, α-methylstyrene,
p-methylstyrene, o-methylstyrene, t-butylstyrene, o-ethylstyrene, p-chlorostyrene,
o-chlorostyrene, 2,4-dichlorostyrene, p-
Aromatic vinyl monomers such as methoxystyrene, o-methoxystyrene and 2,4-dimethylstyrene; methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, acrylic acid -2-ethylhexyl, methacrylic acid-
(Meth) acrylate monomers such as 2-ethylhexyl, dodecyl acrylate, dodecyl methacrylate, tridecyl acrylate, tridecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate;
Vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; α, β-unsaturated carboxylic acids such as maleic anhydride; maleimide monomers such as N-phenylmaleimide, N-methylmaleimide and N-cyclohexylmaleimide Epoxy group-containing monomers such as glycidyl methacrylate; vinyl ether-based monomers such as vinyl methyl ether and vinyl ethyl ether; vinyl carboxylate-based monomers such as vinyl acetate and vinyl butyrate; ethylene, propylene, isobutylene and the like Olefin-based monomers; and diene-based monomers such as butadiene, isoprene, and dimethylbutadiene. These monomers can be used alone or in combination of two or more.

Among these monomers, preferred from the viewpoint of affinity with the ethylene-α-olefin-nonconjugated diene copolymer rubber composition are aromatic vinyl monomers,
Monomers containing at least 20% by weight of one or more monomers selected from the group consisting of (meth) acrylate-based monomers can be exemplified. Particularly preferred examples include those containing 20% by weight or more of an alkyl (meth) acrylate monomer having 5 to 30 carbon atoms in the alkyl group.

The content of polytetrafluoroethylene in the polytetrafluoroethylene-containing mixed powder used in the present invention is preferably from 0.1% by weight to 90% by weight, more preferably from 5% by weight to 85% by weight. More preferably, there is. If it is less than 0.1% by weight, the effect of improving the moldability becomes insufficient, and if it exceeds 90% by weight, the surface appearance may be adversely affected.

The mixed powder containing polytetrafluoroethylene used in the present invention is poured into hot water in which a metal salt such as calcium chloride or magnesium sulfate is dissolved, salted out, solidified, and dried. Alternatively, it can be powderized by spray drying.

[0022] Normal polytetrafluoroethylene fine powder forms aggregates of 100 µm or more in the step of recovering as a powder from the state of a particle dispersion, so that it is difficult to uniformly disperse it in a thermoplastic resin. On the other hand, the polytetrafluoroethylene-containing mixed powder used in the present invention is an ethylene-α-olefin-non-conjugated diene copolymer because polytetrafluoroethylene alone does not form a domain having a particle diameter of more than 10 μm. Excellent dispersibility in rubber. As a result, the ethylene-α-olefin-nonconjugated diene copolymer rubber composition of the present invention has polytetrafluoroethylene having ethylene-α
Fine fibers are efficiently formed in the olefin-non-conjugated diene copolymer rubber, and various moldability is excellent, and also the surface property is excellent.

The resin composition of the present invention comprises the ethylene-α
-The polytetrafluoroethylene-containing mixed powder (B) has a polytetrafluoroethylene component content of 0.0 to 100 parts by weight of the olefin-nonconjugated diene copolymer rubber (A).
001 to 20 parts by weight. If it is less than 0.0001 part, the effect of improving workability is poor, and if it exceeds 20 parts by weight, the fluidity at the time of melting may be too low.

In the present invention, the polytetrafluoroethylene-containing mixed powder (B) is used as a polyolefin resin (C).
And the ethylene-α-
It can also be blended with the olefin-non-conjugated diene copolymer rubber composition (A).

The polyolefin resin (C) used in the present invention
As, for example, a homopolymer or copolymer of an olefin monomer obtained by radical polymerization, ionic polymerization, or the like, a copolymer of a dominant amount of an olefin monomer and a inferior amount of a vinyl monomer, Examples include those containing a copolymer of an olefin monomer and a diene monomer as a main component, and these may be used alone or in combination of two or more. Known catalysts such as a Ziegler catalyst, a chromium catalyst, and a metallocene catalyst are used as the catalyst.

The olefinic monomer referred to herein includes:
Examples thereof include ethylene, propylene, butene-1, hexene-1, decene-1, octene-1, and 4-methyl-pentene-1, with ethylene and propylene being particularly preferred. Specific examples of the olefin-based monomer homopolymer or copolymer include low-density polyethylene, ultra-low-density polyethylene, ultra-low-density polyethylene, linear low-density polyethylene, high-density polyethylene, ultra-high-molecular-weight polyethylene, polypropylene , Ethylene-propylene copolymer, polymethylpentene, polybutene and the like. These olefin polymers are used alone or in combination of two or more. Among these, a polyolefin resin containing, as a main component, one or a mixture of two or more selected from the group consisting of polyethylene, polypropylene, and ethylene-propylene copolymer is particularly preferable.

The ethylene-α-olefin-non-conjugated diene copolymer rubber composition of the present invention is obtained by blending a filler, a softening agent, a crosslinking agent, a foaming agent and the like, if necessary, into a rubber compound. Crosslinking and foaming are performed by a commonly used method to produce a sponge rubber.

As the filler, for example, SRF, FE
Carbon blacks such as F, HAF, ISAF, SAF, FT, and MT; and inorganic fillers such as fine silica particles, calcium carbonate, magnesium carbonate, clay, and talc. These fillers can be used alone or in combination of two or more. The amount of the filler is usually 50 to 200 parts by weight based on 100 parts by weight of the total of the low molecular weight component and the high molecular weight component.

Examples of the softening agent include aromatic oils, process oils such as naphthenic oils and paraffin oils, and vegetable oils such as coconut oil, which are usually used for rubber. Of these softeners, process oils are preferred, and paraffin oil is particularly preferred. These softeners can be used alone or in combination of two or more. The amount of the softener is usually 30 parts by weight or more based on 100 parts by weight of the ethylene-α-olefin-nonconjugated diene copolymer rubber.

Examples of the crosslinking agent include sulfur such as powdered sulfur, precipitated sulfur, colloidal sulfur and insoluble sulfur; inorganic vulcanizing agents such as sulfur chloride, selenium and tellurium; morpholine disulfides, alkylphenol disulfides;
Sulfur-containing organic compounds such as thiuram disulfides and dithiocarbamic acids; 1,1-di-t-butylperoxy-
3,3,5-trimethylcyclohexane, di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di (t
Organic peroxides such as -butylperoxy) hexane and 1,3-bis (t-butylperoxy-isopropyl) benzene. These crosslinking agents can be used alone or in combination of two or more.
The amount of the crosslinking agent varies depending on the type of the crosslinking agent,
For example, in the case of sulfur, based on 100 parts by weight of the ethylene-α-olefin-nonconjugated diene copolymer rubber composition,
0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight. When sulfur is used as a cross-linking agent, a vulcanization accelerator and a vulcanization accelerator can be further compounded, if necessary.
Examples of such a vulcanization accelerator include aldehyde ammonias such as hexamethylenetetramine and acetaldehyde ammonia; guanidines such as diphenylguanidine, di (o-tolyl) guanidine, o-tolyl-biguanide; thiocarbanilide and di (o- Thioureas such as tolyl) thiourea, N, N'-diethylthiourea, tetramethylthiourea, trimethylthiourea, dilaurylthiourea; mercaptobenzothiazole, dibenzothiazole disulfide, 2- (4-morpholinothio) benzothiazole, 2- ( Benzothiazoles such as 2,4-dinitrophenyl) mercaptobenzothiazole and N, N ′-(diethylthiocarbamoylthio) benzothiazole; Nt-butyl-2-benzothiazylsulfenamide; N'- dicyclohexyl-2
Sulfenamides such as benzothiazylsulfenamide, N, N'-diisopropyl-2-benzothiazylsulfenamide, N-cyclohexyl-2-benzothiazylsulfenamide; tetramethylthiuram disulfide, tetraethylthiuram disulfide Thiurams such as tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram tetrasulfide; zinc dimethylthiocarbamate, zinc diethylthiocarbamate, zinc di-n-butylthiocarbamate, zinc ethylphenyldithiocarbamate ,
Sodium dimethyldithiocarbamate, copper dimethyldithiocarbamate, tellurium dimethylthiocarbamate,
Thiocarbamates such as iron dimethylthiocarbamate; and xanthates such as zinc butylthioxanthate and zinc isopropylxanthate. These vulcanization accelerators can be used alone or in combination of two or more. The amount of the vulcanization accelerator is usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the ethylene-α-olefin-nonconjugated diene copolymer rubber. . Examples of the vulcanization accelerating aid include metal oxides such as magnesium oxide, zinc white, litharge, leadtan, and lead white; and organic acids such as stearic acid, oleic acid, and zinc stearate. Particularly, zinc white and stearic acid are preferred. These vulcanization accelerators can be used alone or in combination of two or more. The amount of the vulcanization accelerator is usually 0.5 to 20 parts by weight based on 100 parts by weight of the ethylene-α-olefin-non-conjugated diene copolymer rubber.

When an organic peroxide is used as a crosslinking agent, a crosslinking aid may be further added as necessary. Examples of such a crosslinking aid include sulfur and sulfur compounds such as sulfur and dipentamethylenethiuram tetrasulfide; polyethylene dimethacrylate, divinylbenzene, diallyl phthalate, triallyl cyanurate, metaphenylene bismaleimide, toluylene bismaleimide and the like. And oxime compounds such as p-quinone oxime and p, p'-benzoylquinone oxime. These crosslinking assistants can be used alone or in combination of two or more.

Examples of the foaming agent include inorganic foaming agents such as ammonium carbonate, sodium bicarbonate and anhydrous sodium nitrate; dinitrosopentamethylenetetramine;
N, N'-dimethyl-N, N'-dinitrosoterephthalamide, benzenesulfonyl hydrazide, p, p'-oxybis (benzenesulfonyl hydrazide), 3,3 '
-Organic blowing agents such as disulfone hydrazide diphenyl sulfone, azoisobutyronitrile, azobisformamide and the like. These foaming agents can be used alone or in combination of two or more. Further, a foaming aid such as a urea-based, organic acid-based, or metal salt-based foaming agent can be used together with the foaming agent. The amount of the foaming agent and the foaming auxiliary varies depending on the kind and the desired degree of foaming, but the foaming agent is usually 0 parts by weight based on 100 parts by weight of the ethylene-α-olefin-nonconjugated diene copolymer rubber. .5-
It is 20 parts by weight, preferably 1 to 15 parts by weight, and the foaming aid is usually 1 to 20 parts by weight.

The ethylene-α-olefin-non-conjugated diene copolymer rubber composition of the present invention may further comprise, if desired,
Other additives such as reinforcing materials, hygroscopic agents, plasticizers, antioxidants, antioxidants, heat stabilizers, ultraviolet absorbers, lubricants, mold release agents, flame retardants, antistatic agents, dyes, pigments and fungicides Can also be blended, and polymers other than the above, for example, natural rubber,
Polyisoprene rubber, polybutadiene rubber, styrene
Butadiene rubber, acrylonitrile-butadiene rubber,
Butyl rubber, acrylic rubber, ethylene-α-olefin copolymer, other ethylene-α-olefin-non-conjugated diene copolymer, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene,
Polypropylene or the like may be blended.

The method and order of compounding each component in producing the sponge rubber are not particularly limited, and a kneader or an extruder can be used, but in particular, a Banbury mixer is used. And ethylene-α
-After kneading olefin-non-conjugated diene copolymer rubber (A), polytetrafluoroethylene-containing mixed powder (B), filler, softener, etc., kneading a crosslinking agent, a foaming agent, etc. using a roll mixer. Is preferred. In addition, when compounding using an extruder, a part of the compounding components may be kneaded by previously kneading with a Banbury mixer or the like and then supplying the extruder, and then supplying the remaining compounding components separately to the extruder.
All the components can be fed to an extruder and kneaded.
At the time of such compounding, compounding other than the above-mentioned ethylene-α-olefin-non-conjugated diene copolymer rubber (A), polytetrafluoroethylene-containing mixed powder (B), filler, softener, cross-linking agent and foaming agent. The components can be added at an appropriate kneading stage. Then, according to the procedure used in the production of ordinary sponge rubber, for example, a method of crosslinking and foaming the rubber compound by heating it in a mold of a known crosslinking and foaming apparatus, or an extruder for the rubber compound. After molding into a desired shape using a method such as heating in a crosslinking tank, etc.
The desired sponge rubber can be manufactured. The heating temperature and the heating time at the time of crosslinking / foaming vary depending on the type of the crosslinking agent and the foaming agent, the degree of foaming, and the like.
50-280 ° C, preferably 180-250 ° C,
The heating time is usually 2 to 15 minutes, preferably 3 to 1 minute.
0 minutes.

Hereinafter, the present invention will be described with reference to Examples.
The present invention is not limited to these.

[0036]

EXAMPLES In each description, "parts" indicate parts by weight, and "%" indicates% by weight.
And physical properties are measured by the following methods.

(1) Solid content concentration: 170 ° C. of the particle dispersion
And dried for 30 minutes.

(2) Particle size distribution, weight average particle size: A solution obtained by diluting a particle dispersion with water was used as a sample liquid, and a dynamic light scattering method (ELS800, manufactured by Otsuka Electronics Co., Ltd., temperature: 25 ° C., scattering angle: 90) Degree).

(3) Zeta potential: 0.0
An electrophoresis method (ELS800, manufactured by Otsuka Electronics Co., Ltd.)
At a temperature of 25 ° C. and a scattering angle of 10 °).

(4) Ethylene / propylene weight ratio: Measured by infrared absorption spectroscopy.

(5) Iodine value: Measured by an infrared absorption spectrum method.

(6) Mooney viscosity (ML1 + 8,120
° C): Measured at a measurement temperature of 120 ° C, a residual heat time of 1 minute, and a time of 8 minutes until the viscosity was read.

(7) Roll workability: The compound (ii) of each of Examples and Comparative Examples was wound around a 10-inch roll at a temperature of 50 ± 5 ° C. with a nip width of 2 mm, and the wound state shown in FIG. The following four stages were used to evaluate the time required to attach.

In FIG. 2, 1 is a rear roll, 2 is a front roll, and 3 is a compound (ii).

(8) Extrusion processability (Garve die rating): A
It evaluated based on STM-D2230.

(9) Shape retention (%): The compound (ii) of each of Examples and Comparative Examples was extruded using a die having the shape shown in FIG. After leaving it for 7 minutes, it is crosslinked and foamed and left at room temperature, and then the ratio of the vertical dimension La to the horizontal dimension Lb at room temperature (L
a / Lb) × 100.

(10) Gelation time: Compound (i) of each of Examples and Comparative Examples was measured at 130 ° C. at a shear strain rate of 20 per second using a stress relaxation measuring device (JSR Elastograph manufactured by Japan Synthetic Rubber Co., Ltd.). The gel rise time was defined as the time at which the rise in torque measured in the above section was started. The longer the gelation time, the harder it is to form a "gel".

(11) Physical properties and specific gravity of sponge: Measured in accordance with the Japan Rubber Association Standards Standard, a physical test method for expanded rubber.

Compression set: According to JIS K6301, a molded product extruded using a die having the shape shown in FIG. 1 was subjected to a compression set of 50% in the longitudinal direction of FIG.
The compression strain after 00 hours was measured.

Surface skin: Based on the smoothness of the surface of the sponge rubber, gloss, the presence or absence of adhesion, etc., the following 3
It was evaluated on a scale.

Excellent: Normal: Not possible Reference Example 1 <Polytetrafluoroethylene-containing powder (B-
Production of 1)> 0.1 part of 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved in a mixed solution of 70 parts of dodecyl methacrylate and 30 parts of methyl methacrylate. 2.0 parts of sodium dodecylbenzenesulfonate and 3 parts of distilled water
Add 00 parts of the mixed solution, and mix
After stirring for 4 minutes at rpm, 30MP was added to the homogenizer.
2 times at the pressure of a, stable dodecyl methacrylate /
A methyl methacrylate preliminary dispersion was obtained. This was charged into a separable flask equipped with a stirring blade, a condenser, a thermocouple, and a nitrogen inlet, the internal temperature was raised to 80 ° C. under a nitrogen stream, and the mixture was stirred for 3 hours to undergo radical polymerization, and dodecyl methacrylate / methyl A methacrylate copolymer particle dispersion (hereinafter referred to as P-1) was obtained.

The solid content concentration of P-1 was 25.1%, the particle size distribution showed a single peak, and the weight average particle size was 190.
nm, and the surface potential was -39 mV.

On the other hand, as a polytetrafluoroethylene-based particle dispersion, Fluon AD manufactured by Asahi Glass Fluoropolymers Co., Ltd.
936 was used. AD936 has a solid content of 63.0%
And containing 5 parts of polyoxyethylene alkylphenyl ether per 100 parts of polytetrafluoroethylene. The particle size distribution of AD936 shows a single peak, the weight average particle size is 290 nm, and the surface potential is −
20 mV.

To 833 parts of AD936, 1167 parts of distilled water was added to obtain a polytetrafluoroethylene particle dispersion F-1 having a solid concentration of 26.2%. F-1 contains 25% of polytetrafluoroethylene particles and 1.2% of polyoxyethylene nonylphenyl ether.

F-1 was mixed with 80 parts (polytetrafluoroethylene 20 parts) and 239.0 parts P-1 (dodecyl methacrylate / methyl methacrylate copolymer 60 parts) with a stirring blade, a condenser, a thermocouple, and nitrogen introduction. The mixture was charged into a separable flask equipped with a mouth and a dropping funnel, and stirred at room temperature for 1 hour under a nitrogen stream. Thereafter, the temperature in the system was raised to 80 ° C., and a mixed solution of 0.001 part of iron (II) sulfate, 0.003 part of disodium ethylenediaminetetraacetate, 0.24 part of Rongalite salt, and 10 parts of distilled water was added. A mixture of 20 parts of methyl methacrylate and 0.1 part of tertiary butyl peroxide was added dropwise over 30 minutes, and after completion of the addition, the internal temperature was maintained at 80 ° C. for 1 hour to complete the radical polymerization. No solid matter was separated through a series of operations, and a uniform particle dispersion was obtained. The solid content concentration of the particle dispersion was 28.6%, the particle size distribution was relatively broad, and the weight average particle size was 220 nm.

349.7 parts of this particle dispersion was poured into 600 parts of 75 ° C. hot water containing 5 parts of calcium chloride, and the solid was separated, filtered and dried to obtain a mixed powder containing polytetrafluoroethylene (B). -1) 98 parts were obtained.

The dried B-1 was shaped into strips at 220 ° C. by a press molding machine, and ultrathin sections were observed with a microtome without staining using a transmission electron microscope.
Polytetrafluoroethylene was observed as a dark part, but no aggregate larger than 10 μm was observed.

Reference Example 2 <Production of Master Pellets (M-1) of Mixed Powder Containing Polytetrafluoroethylene> In Reference Example 1, 60 parts of a polypropylene resin [Novatech PP (FY4) manufactured by Nippon Polychem Co., Ltd.] was used. After blending 40 parts of the obtained tetrafluoroethylene-containing mixed powder B-1 and hand blending, a twin-screw extruder (WERNER & P) was used.
Using a melter kneading at a barrel temperature of 240 ° C. and a screw rotation speed of 200 rpm, the mixture was shaped into pellets by using FSKLEDERER ZSK30) to obtain a master pellet (hereinafter referred to as M-1) of a polytetrafluoroethylene-containing mixed powder. Obtained.

Examples 1 to 6 and Comparative Examples 1 to 3 The rubber shown in Table 1 was blended with the component [I] shown in Table 2 and B-1 or M-1 obtained in each Reference Example. A compound (i) was obtained by kneading using a Banbury mixer (internal capacity: 1.7 liters) at 130 rpm and a rotation speed of 80 rpm for 200 seconds. To the compound (i), the component [II] shown in Table 2 was blended, and the mixture was kept at 50 ° C.
Using a 0-inch roll mixer, the number of rotations of the front roll (r
(pm) / post-roll rotation speed (rpm) = 24/22, and kneaded for 5 minutes to obtain compound (ii). Then, a garbage die (ASTM-D2330) was placed in a 50 mm extruder.
The compound (ii) was extruded at a cylinder temperature of 60 ° C., a die temperature of 80 ° C., and a screw rotation speed of 30 rpm, and the extrudability was evaluated. A die having the shape shown in FIG. 2 was attached to a 50 mm extruder, the cylinder temperature was set at 60 ° C., the die temperature was set at 80 ° C., and the screw rotation speed was set at 30 rpm. 5 in hot air bath
The mixture was heated for one minute to perform crosslinking and foaming, thereby obtaining a sponge rubber. Table 2 shows the evaluation results of each compound and sponge rubber.

As a result, the copolymer rubber composition of the present invention
It has high foaming properties, low sponge specific gravity, and excellent roll processability and extrusion processability, especially hard to generate "gel",
In addition, the sponge rubber has excellent shape retention at the time of crosslinking and foaming, and has a small compression set and a good surface texture.

On the other hand, for comparison, a mixture extruded without adding a polytetrafluoroethylene-containing mixed powder (Comparative Example 1), and a polytetrafluoroethylene fine powder (CD123 manufactured by Asahi ICI) were added. Those (Comparative Examples 2 and 3) were similarly evaluated. Table 2 shows the results.

[0062]

[Table 1]

[Table 2]

[0063]

The ethylene-α-olefin-nonconjugated diene copolymer rubber composition of the present invention has a high melt tension.
It has high foaming properties during foaming, kneading workability, roll workability,
It has excellent extrudability and hardly generates "gel", and when highly foamed, it has excellent shape retention during crosslinking and foaming,
The compression set is small, the sponge surface skin is good, and it has an excellent property balance. Therefore, in particular, it can be very suitably used as a sponge rubber, as a sealing material for automobile door seals, roof side rails, trunk seals, etc., as well as other transportation sealing materials, civil engineering / architecture sealing materials, and general machinery. -Useful for a wide range of applications including sealing materials for equipment, wire coating, extruded products, etc.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a wrapped state of a compound (ii) during roll processing.

FIG. 2 is a view showing the shape of a die used for evaluation of shape retention and compression set.

[Explanation of symbols]

 1 Back roll 2 Front roll 3 Compound (ii)

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4J002 AC022 AC032 AC062 BB032 BB034 BB101 BB122 BB124 BB151 BB154 BB171 BB174 BB182 BB191 BB194 BC032 BC082 BC092 BC112 BC122 BD153 BE042 BF012 BF022 BG042 BG05102 BG06 CD02 BD022

Claims (2)

[Claims] 1. A particle diameter of 10 to 100 parts by weight of an ethylene-α-olefin-non-conjugated diene copolymer rubber (A).
The polytetrafluoroethylene-containing mixed powder (B) comprising the polytetrafluoroethylene particles (a) and the organic polymer (b) having a particle size of μm or less has a polytetrafluoroethylene component of 0.0001 to 20 parts by weight. Ethylene-α-olefin-non-conjugated diene copolymer rubber composition compounded as described above. 2. An ethylene-α-olefin-non-conjugated diene copolymer rubber (A) of 100 parts by weight has a particle diameter of 10 parts by weight.
A master pellet comprising a polytetrafluoroethylene-containing mixed powder (B) comprising polytetrafluoroethylene particles (a) having a particle size of not more than μm and an organic polymer (b) and a polyolefin resin (C) comprises a polytetrafluoroethylene component Is an ethylene-α-olefin-non-conjugated diene copolymer rubber composition blended so as to be 0.0001 to 20 parts by weight.