WO2017002957A1 - Ethylene-propylene-diene rubber foam and sealing material - Google Patents

Abstract

This ethylene-propylene-diene rubber foam is obtained by foaming a rubber composition containing an ethylene-propylene-diene rubber, a crosslinking agent, a crosslinking accelerator, a foaming agent, a foaming assistant, and a nonionic surfactant, and has a stretch rate of 300-1000%.

Description

Ethylene / propylene / diene rubber foam and sealing material

The present invention relates to an ethylene / propylene / diene rubber foam and a sealing material, and more particularly to an ethylene / propylene / diene rubber foam and a sealing material having the same.

Conventionally, ethylene, propylene, diene rubber (hereinafter referred to as EPDM) has been used as a sealing material in various industrial products such as automobiles, housing equipment, and household appliances to prevent the intrusion of water and sound by filling the gaps in the products. EPDM foams obtained by foaming are known.

EPDM foam is generally produced by foaming EPDM with a foaming agent and crosslinking with a crosslinking agent.

As such an EPDM foam, for example, an EPDM foam obtained by foaming a rubber composition containing EPDM, a quinoid crosslinking agent, a foaming agent, and the like has been proposed (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2012-17452

Incidentally, in recent years, the demand for water-stopping of EPDM foam has further increased, and further improvement in water-stopping has been demanded.

An object of the present invention is to provide an ethylene / propylene / diene rubber foam having good water blocking properties and a sealing material provided with the same.

The present invention [1] is obtained by foaming a rubber composition containing an ethylene / propylene / diene rubber, a crosslinking agent, a crosslinking accelerator, a foaming agent, a foaming aid and a nonionic surfactant, and has an elongation percentage. And an ethylene / propylene / diene rubber foam of 300% or more and 1000% or less.

The present invention [2] includes the ethylene / propylene / diene rubber foam according to [1], wherein the nonionic surfactant is a fatty acid amide.

This invention [3] is [1] or [2] whose content rate of the said nonionic surfactant is 3 to 20 mass parts with respect to 100 mass parts of said ethylene-propylene-diene rubbers. It contains the described ethylene / propylene / diene rubber foam.

In the present invention [4], the rubber composition contains the ethylene / propylene / diene rubber foam according to any one of [1] to [3], which further contains an aromatic sulfinic acid compound.

In the invention [5], the content ratio of the aromatic sulfinic acid compound is 10 parts by mass or more and 300 parts by mass or less with respect to 100 parts by mass of the nonionic surfactant. Contains propylene diene rubber foam.

The present invention [6], apparent density, a 0.050 g / cm ³ or more 0.200 g / cm ³ or less [1] to the ethylene-propylene-diene rubber foamed material according to any one of [5] Contains.

The invention [7] is a foam of ethylene / propylene / diene rubber according to any one of [1] to [6], wherein the 50% compression load is 0.1 N / cm ² or more and 2.0 N / cm ² or less. Contains the body.

The present invention [8] is a sealing material for filling gaps between members, and the ethylene / propylene / diene rubber foam according to any one of [1] to [7] and the ethylene / propylene / A sealing material including an adhesive layer provided on at least one surface of the diene rubber foam is included.

The ethylene / propylene / diene rubber foam of the present invention is obtained by foaming a rubber composition containing ethylene / propylene / diene rubber, a crosslinking agent, a crosslinking accelerator, a foaming agent, a foaming aid and a nonionic surfactant. The elongation is 300% or more and 1000% or less. Therefore, the water stopping property is good.

Further, according to the sealing material of the present invention, since the above-mentioned ethylene / propylene / diene rubber foam is provided, the gap between the members can be reliably filled and sealed.

FIG. 1 is a schematic view showing an embodiment of the sealing material of the present invention. FIG. 2 is a schematic view showing an outline of the water-stop test.

The ethylene / propylene / diene rubber (hereinafter sometimes referred to as EPDM) foam of the present invention is a rubber containing EPDM, a crosslinking agent, a crosslinking accelerator, a foaming agent, a foaming aid, and a nonionic surfactant. It is obtained by foaming the composition.

EPDM is a rubber obtained by copolymerization of ethylene, propylene and dienes. In addition to ethylene and propylene, dienes are further copolymerized to introduce unsaturated bonds and to be crosslinked by a crosslinking agent described later. Is possible.

Examples of dienes include 5-ethylidene-2-norbornene, 1,4-hexadiene, dicyclopentadiene, and the like. These dienes can be used alone or in combination of two or more.

As EPDM, for example, EPDM having a diene content (diene content) of less than 7.0% by mass (hereinafter, also referred to as “low diene EPDM”), EPDM having a diene content of 7.0% by mass or more. (Hereinafter also referred to as “high diene EPDM”).

The diene content of the low diene EPDM is less than 7.0% by mass, preferably 6.0% by mass or less, more preferably 5.0% by mass or less, and for example, 1.0% by mass or more, preferably Is 4.0 mass% or more. In addition, the amount of diene can be calculated | required by the mass ratio of raw material preparation. It can also be determined according to ASTM D 6047.

When the EPDM contains a low diene EPDM, the dienes in the low diene EPDM are preferably 5-ethylidene-2-norbornene among the above. Thereby, the EPDM foam of a low density and a low compression set can be obtained reliably.

For the low diene EPDM, a known method such as polymerization with a catalyst such as a Ziegler-Natta catalyst, a metallocene catalyst, or a vanadium catalyst is employed.

The Mooney viscosity of the low diene EPDM is, for example, 1 (ML1 + 4, at 125 ° C) or more, preferably 10 (ML1 + 4, at125 ° C) or more, more preferably 35 (ML1 + 4, at125 ° C) or more. 100 (ML1 + 4, at 125 ° C.) or less, preferably 50 (ML 1 + 4, at 125 ° C.) or less.

The diene content of the high diene EPDM is 7.0% by mass or more, preferably 9.0% by mass or more, and for example, 15.0% by mass or less, preferably 12.0% by mass or less.

When the EPDM contains a high diene EPDM, the dienes in the high diene EPDM are preferably 5-ethylidene-2-norbornene among the above. Thereby, the EPDM foam of a low density and a low compression set can be obtained reliably.

The high diene EPDM preferably has a long chain branched structure. That is, in the viscoelasticity measurement (measurement temperature: 190 ° C., rotation angle: 1 °)), the complex viscosity η ^* (Γ = 0.15) of the shear rate (Γ = 0.15 (1 / s)) and the shear The ratio (η ^* (Γ = 0.15) / η ^* (Γ = 17.5)) of the speed (Γ = 17.5 (1 / s)) and the complex viscosity η ^* (Γ = 17.5) is For example, 9 or more, preferably 10 or more, and for example, 60 or less, preferably 40 or less, more preferably 20 or less. When the high diene EPDM has a long chain branched structure, the elongation viscosity increases due to the entanglement of the side chains, so that the rubber composition can be foamed well and the density of the EPDM foam can be further reduced. .

Viscoelasticity measurement is performed using a rheometer (RPA2000; manufactured by Alpha Technologies).

As a method for introducing a long branched chain structure into EPDM, a polymerization with a metallocene catalyst is preferable.

The Mooney viscosity of the high diene EPDM is, for example, 1 (ML1 + 4, at 100 ° C.) or more, preferably 10 (ML1 + 4, at 100 ° C.) or more, and for example, 100 (ML1 + 4, at 100 ° C.) or less, preferably 35 (ML1 + 4, at 100 ° C.).

The EPDM of the present invention may contain at least one of a low diene EPDM and a high diene EPDM, but preferably a low diene EPDM and a high diene EPDM are used in combination.

When EPDM uses low diene EPDM and high diene EPDM in combination, for example, the mass ratio of low diene EPDM to high diene EPDM is, for example, 5:95 to 95: 5, preferably 15:85 to 85:15. More preferably, it is 50:50 to 85:15, further preferably 55:45 to 80:20, and particularly preferably 60:40 to 80:20. By setting the mass ratio of the low diene EPDM and the high diene EPDM in the above-mentioned range, in particular, by increasing the content ratio of the low diene EPDM to the content ratio of the high diene EPDM, the EPDM having a low density and a low compression set. A foam can be obtained reliably.

The content ratio of EPDM (total amount of high diene EPDM and low diene EPDM) in the rubber composition is, for example, 5% by mass or more, preferably 10% by mass or more, and for example, 80% by mass or less, preferably It is 50 mass% or less, More preferably, it is 40 mass% or less.

Examples of the crosslinking agent include sulfur, for example, sulfur compounds such as 4,4′-dithiodimorpholine, for example, p-quinonedioxime, p, p′-dibenzoylquinonedioxime, poly-p-dinitrosobenzene. Quinoid compounds such as dicumyl peroxide, dimethyldi (t-butylperoxy) hexane, 1,1-di (t-butylperoxy) cyclohexane, α, α'-di (t-butylperoxy) diisopropyl Organic peroxides such as benzene, for example, nitroso compounds such as p-dinitrosobenzene, for example, formaldehyde resins such as alkylphenol-formaldehyde resins, melamine-formaldehyde condensates, and ammonium salts such as ammonium benzoate, etc. It is done. Moreover, for example, selenium, magnesium oxide, lead monoxide, polyamine and the like can be mentioned. These crosslinking agents can be used alone or in combination of two or more.

From the viewpoints of low density, low compressive load, water stoppage, etc., sulfur, sulfur compounds, and more preferably sulfur are preferable.

The content of the crosslinking agent is, for example, 0.1 parts by mass or more, preferably 1 part by mass or more, and for example, 20 parts by mass or less, preferably 10 parts by mass or less, with respect to 100 parts by mass of EPDM. More preferably, it is 5 parts by mass or less.

Examples of the crosslinking accelerator include thiazoles such as dibenzothiazyl disulfide and 2-mercaptobenzothiazole, thioureas such as diethylthiourea, trimethylthiourea, and dibutylthiourea such as sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, Dithiocarbamates such as zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibenzyldithiocarbamate, for example, guanidines such as diphenylguanidine, di-o-tolylguanidine, for example, benzothiazyl-2-diethylsulfenamide, N- Sulfenamides such as cyclohexyl-2-benzothiazylsulfenamide, such as tetramethylthiuram monosulfide, tetra Thiurams such as tilthiuram disulfide and tetrabenzylthiuram disulfide, for example, xanthogenic acids such as sodium isopropylxanthate and zinc isopropylxanthate, for example, aldehyde ammonias such as acetaldehyde ammonia and hexamethylenetetramine, for example n-butyraldehyde aniline And aldehyde amines such as butyraldehyde monobutylamine, for example, alcohols such as ethanol, ethylene glycol, glycerin, polyethylene glycol, and polypropylene glycol. These crosslinking accelerators can be used alone or in combination of two or more.

Preferred crosslinking accelerators include thiazoles, thioureas, and dithiocarbamates, more preferably thiazoles and dithiocarbamates, and more preferably a combination of thiazoles and dithiocarbamates. .

The content ratio of the crosslinking accelerator is, for example, 0.1 parts by mass or more, preferably 0.5 parts by mass or more, and, for example, 15 parts by mass or less, preferably 5 parts by mass with respect to 100 parts by mass of EPDM. Or less. Moreover, it is 1 mass part or more with respect to 100 mass parts of crosslinking agents, Preferably, it is 10 mass parts or more, for example, is 100 mass parts or less, Preferably, it is 50 mass parts or less.

When the rubber composition contains a crosslinking accelerator, the speed of the crosslinking reaction by the crosslinking agent can be increased. Therefore, the obtained EPDM foam has a small stress relaxation and can retain a repulsive stress, and therefore has a good water stop characteristic.

Examples of the foaming agent include organic foaming agents and inorganic foaming agents.

Examples of the organic foaming agent include azo foaming agents such as azodicarbonamide (ADCA), barium azodicarboxylate, azobisisobutyronitrile (AIBN), azocyclohexylnitrile, azodiaminobenzene, and the like. N-nitroso-based blowing agents such as N′-dinitrosopentamethylenetetramine (DTP), N, N′-dimethyl-N, N′-dinitrosoterephthalamide, trinitrosotrimethyltriamine, such as 4,4′-oxybis (Benzenesulfonyl hydrazide) (OBSH), paratoluenesulfonyl hydrazide, diphenylsulfone-3,3'-disulfonyl hydrazide, 2,4-toluene disulfonyl hydrazide, p, p-bis (benzenesulfonyl hydrazide) ether, benzene-1 , 3-Disulfo Hydrazide-based blowing agents such as nylhydrazide and allylbis (sulfonylhydrazide), for example, p-toluylenesulfonyl semicarbazide and semicarbazide-based blowing agents such as 4,4′-oxybis (benzenesulfonyl semicarbazide), such as trichloromonofluoromethane, dichloro Other known organic foaming agents such as fluorinated alkane foaming agents such as monofluoromethane, for example, triazole foaming agents such as 5-morpholyl-1,2,3,4-thiatriazole, and the like.

Examples of the organic foaming agent include thermally expandable fine particles in which a heat-expandable substance is enclosed in a microcapsule. Examples of such thermally expandable particles include microspheres (trade name, Matsumoto). And commercial products such as those manufactured by Yushi Corporation.

Examples of the inorganic foaming agent include hydrogen carbonates such as sodium hydrogen carbonate and ammonium hydrogen carbonate, for example, carbonates such as sodium carbonate and ammonium carbonate, for example, nitrites such as sodium nitrite and ammonium nitrite, for example hydrogen. Other known inorganic foaming agents such as borohydride salts such as sodium borohydride, for example, azides, and the like can be mentioned.

These foaming agents can be used alone or in combination of two or more.

Preferably, an organic foaming agent, more preferably an azo foaming agent, and even more preferably ADCA. Thereby, the EPDM foam of a low density and a low compressive load can be obtained reliably.

The content of the foaming agent is, for example, 5 parts by mass or more, preferably 10 parts by mass or more, and for example, 50 parts by mass or less, preferably 30 parts by mass or less with respect to 100 parts by mass of EPDM.

Examples of foaming aids include salicylic acid-based foaming aids, benzoic acid-based foaming aids, urea-based foaming aids, and metal oxides (eg, zinc oxide). These foaming assistants can be used alone or in combination of two or more.

Preferably, a metal oxide, more preferably zinc oxide is used.

The content ratio of the foaming assistant is, for example, 1 part by mass or more, preferably 3 parts by mass or more, and for example, 20 parts by mass or less, preferably 15 parts by mass or less with respect to 100 parts by mass of EPDM. . Moreover, it is 1 mass part or more with respect to 100 mass parts of foaming agents, Preferably, it is 10 mass parts or more, for example, is 100 mass parts or less, Preferably, it is 50 mass parts or less.

When the rubber composition contains a foaming aid, the foaming temperature (for example, the decomposition temperature of the organic foaming agent) can be lowered during foaming. Therefore, the EPDM foam obtained is a foam with a low density and a low compression load.

Nonionic surfactants contain hydrophilic groups (eg, amide groups, polyoxyethylene groups, monooxyethylene groups, hydroxyl groups) and hydrophobic groups (eg, C ₆ -C ₂₄ aliphatic groups). It is a nonionic compound.

Preferred examples of the nonionic surfactant include fatty acid amides, polyoxyethylenes, and monooxyethylenes.

Examples of fatty acid amides include fatty acid monoamides such as stearic acid monoamide, oleic acid monoamide, and erucic acid monoamide, such as ethylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, and ethylene bishydroxystearic acid. Amide, Ethylene bis behenic acid amide, Hexamethylene bis stearic acid amide, Hexamethylene bis behenic acid amide, Hexamethylene bishydroxy stearic acid amide, Ethylene bis oleic acid amide, Ethylene bis erucic acid amide, Hexamethylene bis oleic acid amide, m Bis-fatty acid amides such as xylylene bis-stearic acid amide, m-xylylene bis-hydroxystearic acid amide, such as N, N′-distearyl adipic acid amide, N, N′-dialkyl fatty acids such as N, N′-distearyl sebacic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide, N, N ′ distearyl isophthalic acid amide Examples include amides.

Examples of polyoxyethylenes include polyoxyethylene ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene monolaurate, polyoxyethylene Examples thereof include polyoxyethylene esters such as oxyethylene monostearate, polyoxyethylene sorbitan monolaurate, and polyoxyethylene sorbitan monostearate.

Examples of monooxyethylenes include ethylene glycol esters such as ethylene glycol distearate.

These nonionic surfactants can be used alone or in combination of two or more.

Preferably, fatty acid amides, more preferably fatty acid monoamides, bis fatty acid amides, still more preferably bis fatty acid amides, and particularly preferably ethylene bis stearic acid amide. Thereby, the water stop of EPDM foam can be made still better. Further, the density and compressive load of the EPDM foam can be further reduced.

The content ratio of the nonionic surfactant is, for example, 1 part by mass or more, preferably 3 parts by mass or more, more preferably 4 parts by mass or more, with respect to 100 parts by mass of EPDM. Part or less, preferably 20 parts by weight or less, more preferably 10 parts by weight or less, and still more preferably 8 parts by weight or less.

When the rubber composition contains a nonionic surfactant, the adhesion between the EPDM foam and the adherend can be improved, and the waterstop property of the EPDM foam can be improved.

The rubber composition preferably contains an aromatic sulfinic acid compound.

The aromatic sulfinic acid compound is preferably an aromatic sulfinic acid metal salt.

Examples of aromatic sulfinic acid metal salts include sodium benzenesulfinate, potassium benzenesulfinate, lithium benzenesulfinate, zinc di-benzenesulfinate, calcium di-benzenesulfinate, lead di-benzenesulfinate, and di-benzene. Benzenesulfinate metal salts such as barium sulfinate, cadmium di-benzenesulfinate, magnesium di-benzenesulfinate; for example, sodium p-toluenesulfinate, potassium p-toluenesulfinate, lithium p-toluenesulfinate, bis- zinc p-toluenesulfinate, calcium bis-p-toluenesulfinate, lead bis-p-toluenesulfinate, barium bis-p-toluenesulfinate, bis-p-toluenesulfinate Toluene sulfinate metal salts such as magnesium, bis-p-toluenesulfinate magnesium; for example, sodium p-chlorobenzenesulfinate, potassium p-chlorobenzenesulfinate, lithium p-chlorobenzenesulfinate, zinc bis-p-chlorobenzenesulfinate, Chlorobenzenesulfinate metal such as calcium bis-p-chlorobenzenesulfinate, lead bis-p-chlorobenzenesulfinate, barium bis-p-chlorobenzenesulfinate, cadmium bis-p-chlorobenzenesulfinate, magnesium bis-p-chlorobenzenesulfinate Salts; for example, sodium 2,4-dimethylbenzenesulfinate, potassium 2,4-dimethylbenzenesulfinate, 2,4-dimethylbenzenesulfine Lithium, zinc bis-2,4-dimethylbenzenesulfinate, calcium bis-2,4-dimethylbenzenesulfinate, lead bis-2,4-dimethylbenzenesulfinate, barium bis-2,4-dimethylbenzenesulfinate, Cadmium bis-2,4-dimethylbenzenesulfinate, magnesium bis-2,4-dimethylbenzenesulfinate, sodium 2,5-dimethylbenzenesulfinate, zinc bis-2,5-dimethylbenzenesulfinate, 3,4- Metal salts of dimethylbenzenesulfinate such as sodium dimethylbenzenesulfinate and zinc bis-3,4-dimethylbenzenesulfinate; for example, sodium 2-chloro-4-methylbenzenesulfinate, bis-2-chloro-4-methylbenzene Zinc sulfinate, 2-methyl Chloromethylbenzenesulfinate metal salts such as sodium 4-chlorobenzenesulfinate, zinc bis-2-methyl-4-chlorobenzenesulfinate, zinc bis-2,3,4,5,6-pentachlorobenzenesulfinate; Fluorobenzenesulfinic acid metal salts such as sodium p-fluorobenzenesulfinate and zinc bis-p-fluorobenzenesulfinate; for example, bromobenzenesulfin such as sodium p-bromobenzenesulfinate and zinc bis-p-bromobenzenesulfinate Acid metal salts; for example, butylbenzenesulfinate metal salts such as sodium p-tert-butylbenzenesulfinate and zinc bis-p-tert-butylbenzenesulfinate; for example, bis-2,3,4,5,6- Pentamethylbenzenes Such as pentamethyl benzene sulfinic acid metal salts such as fins zinc and the like. These aromatic sulfinic acid compounds can be used alone or in combination of two or more.

Preferably, toluenesulfinic acid metal salts are used, more preferably zinc bis-p-toluenesulfinate.

The content ratio of the aromatic sulfinic acid compound is, for example, 1 part by mass or more, preferably 2 parts by mass or more, more preferably 3 parts by mass or more, and further preferably 4 parts by mass or more with respect to 100 parts by mass of EPDM. Yes, for example, 20 parts by mass or less, preferably 15 parts by mass or less, more preferably 8 parts by mass or less. Moreover, the content rate of an aromatic sulfinic acid compound is 10 mass parts or more with respect to 100 mass parts of nonionic surfactants, Preferably, it is 50 mass parts or more, More preferably, it is 70 mass parts or more. Also, for example, it is 300 parts by mass or less, preferably 150 parts by mass or less, and more preferably 90 parts by mass or less. By setting the content ratio of the aromatic sulfinic acid compound in the above range, the water stoppage can be further improved while suppressing fogging. In addition, an EPDM foam having a low density and a low compressive load can be obtained with certainty.

When the rubber composition contains an aromatic sulfinic acid compound, the aromatic sulfinic acid compound plays a role as a foaming aid, promotes the foamability of the foaming agent, and improves the foamability and flexibility of the EPDM foam. Can be improved. Moreover, since the aromatic sulfinic acid compound suppresses generation of fogging-causing substances such as urea, fogging of the EPDM foam can be suppressed.

The rubber composition preferably contains a basic metal compound.

Examples of the basic metal compound include basic oxides such as calcium oxide, magnesium oxide, ferrous oxide (FeO), and ferric oxide (Fe ₂ O ₃ ), such as calcium hydroxide and magnesium hydroxide. And basic hydroxides. These basic metal compounds can be used alone or in combination of two or more.

From the viewpoints of fogging suppression, water-stopping property, etc., calcium oxide and magnesium hydroxide are preferable, and calcium oxide is more preferable.

The content of the basic metal compound is, for example, 1 part by mass or more, preferably 3 parts by mass or more, and for example, 20 parts by mass or less, preferably 10 parts by mass or less with respect to 100 parts by mass of EPDM. is there.

Since the rubber composition contains a basic metal compound, the basic metal compound traps a decomposition product (for example, cyanic acid) generated by the decomposition of the foaming agent (for example, ADCA). Generation of (for example, urea) can be suppressed. As a result, fogging of the EPDM foam can be suppressed.

Further, the rubber composition may contain a softener, a filler, a processing aid, a pigment, and the like as appropriate, if necessary.

Examples of the softener include dry oils, animal and vegetable oils (eg flaxseed oil), asphalts (eg blown asphalt), petroleum oils (eg paraffinic process oil, naphthenic process oil, aroma Process oils), low molecular weight polymers, organic acid esters (eg, phthalate esters (eg, di-2-ethylhexyl phthalate (DOP), dibutyl phthalate (DBP)), phosphate esters, higher fatty acid esters , Alkyl sulfonic acid ester, etc.). These softeners can be used alone or in combination of two or more. Preferably, asphalt and petroleum oils are used.

The content ratio of the softening agent is, for example, 50 parts by mass or more, preferably 110 parts by mass or more, and for example, 250 parts by mass or less, preferably 180 parts by mass or less with respect to 100 parts by mass of EPDM.

Examples of the filler include inorganic fillers such as calcium carbonate, magnesium carbonate, silicic acid and salts thereof, clay, talc, mica powder, bentonite, silica, alumina, aluminum silicate, aluminum powder, and organic materials such as cork. System fillers and other known fillers. These fillers can be used alone or in combination of two or more. Preferably, an inorganic filler, more preferably calcium carbonate is used.

The content of the filler is, for example, 50 parts by mass or more, preferably 80 parts by mass or more, more preferably 110 parts by mass or more, and for example, 250 parts by mass or less, preferably 100 parts by mass of EPDM. Is 180 parts by mass or less, more preferably 130 parts by mass or less.

Examples of processing aids include stearic acid and esters thereof, and zinc stearate. These processing aids can be used alone or in combination of two or more.

The content of the processing aid is, for example, 0.1 parts by mass or more, preferably 3 parts by mass or more, and, for example, 20 parts by mass or less, preferably 15 parts by mass or less with respect to 100 parts by mass of EPDM. It is.

Examples of the pigment include carbon black. The average particle diameter of the pigment is, for example, 1 μm or more and 200 μm or less. These pigments can be used alone or in combination of two or more.

The content ratio of the pigment is, for example, 1 part by mass or more, preferably 2 parts by mass or more, and for example, 50 parts by mass or less, preferably 30 parts by mass or less with respect to 100 parts by mass of EPDM.

Furthermore, the rubber composition can be used, for example, in the range that does not affect the excellent effect of the obtained EPDM foam, depending on its purpose and application, for example, polymer, flame retardant, tackifier, anti-aging agent, antioxidant, coloring Known additives such as agents and fungicides can be contained in an appropriate ratio.

The rubber composition is preferably substantially free of urea. Thereby, generation | occurrence | production of fogging can be suppressed. The content ratio of urea is 1.0% by mass or less, preferably 0.5% by mass or less, and more preferably 0% by mass with respect to the rubber composition.

Next, a method for producing an EPDM foam will be described.

In order to produce an EPDM foam, first, the above-described components are blended and kneaded using a kneader, a mixer, a mixing roll, or the like to knead the rubber composition as an admixture (kneading step).

In the kneading step, for example, first, a component other than a crosslinking agent, a crosslinking accelerator, a nonionic surfactant, an aromatic sulfinic acid compound, and a basic metal compound is kneaded to obtain a primary mixture, , Adding a cross-linking agent, a cross-linking accelerator, a nonionic surfactant, an aromatic sulfinic acid compound, and a basic metal compound to the primary mixture and kneading to obtain a rubber composition (secondary mixture) You can also. Further, in the kneading step, kneading can be performed while appropriately heating.

Then, the obtained rubber composition (admixture) is extruded into a sheet or the like using an extruder (molding step), and then the extruded rubber composition is heated to foam (foaming). Process).

The rubber composition is appropriately selected according to the crosslinking start temperature of the blended crosslinking agent, the foaming temperature of the blended foaming agent, and the like, for example, using a hot air circulating oven, for example, 40 ° C. or higher, preferably 60 ° C. or higher, for example, 200 ° C. or lower, preferably 160 ° C. or lower, for example, 1 minute or longer, preferably 5 minutes or longer, and for example, 60 minutes or shorter, preferably 40 minutes or shorter, Preheat. After preheating, for example, 450 ° C. or less, preferably 250 ° C. or less, for example, 100 ° C. or more, preferably 160 ° C. or more, for example, 5 minutes or more, preferably 10 minutes or more, or, for example, 80 Heated for not more than minutes, preferably not more than 50 minutes.

Thereby, the rubber composition is crosslinked while being foamed to obtain an EPDM foam.

According to such a method for producing an EPDM foam, an EPDM foam having good water-stopping and elongation can be produced easily and reliably.

The obtained rubber composition is extruded into a sheet shape (molding step) while being heated using an extruder (that is, a rubber composition sheet is produced) to obtain a sheet-like rubber composition. The (rubber composition sheet) can also be continuously crosslinked and foamed (foaming step). According to this method, the EPDM foam can be produced with high production efficiency.

The thickness of the obtained EPDM foam is, for example, 0.1 mm or more, preferably 1 mm or more, and for example, 50 mm or less, preferably 45 mm or less.

The EPDM foam has, for example, an open-cell structure (open cell ratio: 100%) or a semi-continuous semi-closed cell structure (open-cell ratio exceeds, for example, 0%, and preferably has an open-cell ratio of 10% or more, For example, it is less than 100%, preferably 98% or less. A semi-continuous semi-closed cell structure is preferable. When the EPDM foam has a semi-continuous semi-closed cell structure, the flexibility can be improved, and consequently, the sealing property of the EPDM foam can be improved with respect to the gap between the members.

The average cell diameter of the EPDM foam is, for example, 100 μm or more, preferably 500 μm or more, more preferably 800 μm or more, and, for example, 1500 μm or less, preferably 1200 μm or less, more preferably 900 μm or less. . When the average cell diameter of the EPDM foam is in the above range, the sealing property and flexibility can be improved.

The volume expansion ratio (density ratio before and after foaming) of the EPDM foam is, for example, 5 times or more, preferably 15 times or more, and for example, 30 times or less.

The apparent density (according to JIS K 6767 (1999)) of the EPDM foam is, for example, 0.050 g / cm ³ or more, preferably 0.080 g / cm ³ or more, more preferably 0.090 g / cm ^3. or more, also, for example, 0.200 g / cm ³ or less, preferably 0.150 g / cm ³ or less, more preferably 0.120 g / cm ³ or less. When the apparent density is in the above range, the flexibility of the EPDM foam can be improved.

The 50% compressive load value (according to JIS K 6767 (1999)) of the EPDM foam is, for example, 0.1 N / cm ² or more, preferably 0.2 N / cm ² or more, more preferably 0.3 N. / cm ² or more, also, for example, 2.0 N / cm ² or less, preferably, 1.0 N / cm ² or less, more preferably 0.5 N / cm ² or less. When the 50% compression load value is in the above range, the flexibility of the EPDM foam is good. Moreover, since the load concerning a member can be reduced when compressing and sealing to a member, while being able to seal a member easily, a deformation | transformation or destruction of a member can be suppressed.

EPDM strength of the foam (JIS K 6767 (maximum load in a tensile test according to 1999)), for example, 1.0 N / cm ² or more, preferably, 5.0 N / cm ² or more, more preferably 7. and at 0N / cm ² or more, and is, for example, 20 N / cm ² or less, preferably, 15N / cm ² or less, more preferably 10 N / cm ² or less. When the tensile strength is within the above range, the strength of the EPDM foam is good.

The elongation of the EPDM foam (according to JIS K-6767 (1999)) is not less than 300% and not more than 1000%. Preferably, it is 500% or more, more preferably 600% or more, and preferably 900% or less, more preferably 800% or less. When the elongation is within the above range, the flexibility of the EPDM foam is good. Further, the EPDM can be brought into close contact with the shape and unevenness of the adherend as various members, and the gaps between the various members can be reliably sealed.

The volatilization amount by fogging of the EPDM foam is, for example, 3.0 mg or less, preferably 1.0 mg or less under the condition that an EPDM foam having a length of 100 mm, a width of 50 mm, and a thickness of 10 mm is left in a sealed container at 100 ° C. for 20 hours. It is. When the volatilization amount is in the above range, it is possible to suppress the occurrence of fogging (fogging) such as glass in the peripheral member.

The EPDM foam is not particularly limited, and seals gaps between various members for automobile use, residential use use, home appliance use, etc. for the purpose of water stop, vibration control, sound absorption, sound insulation, dust prevention, heat insulation, buffering, etc. can do. For example, it can be used as a water-stopping material, a vibration-proofing material, a sound-absorbing material, a sound-insulating material, a dust-proofing material, a heat-insulating material, a shock-absorbing material and the like. Preferably, it can be used as a water stop material for the purpose of water stop. More specifically, gaps between automobile casings and parts (for example, instrument panels, door trims, air ducts, door speakers, taillights, etc.), electrical and electrical equipment casings and parts (for example, engine control units (ECUs)) Etc.).

The EPDM foam is obtained by foaming a rubber composition containing ethylene / propylene / diene rubber, a crosslinking agent, a crosslinking accelerator, a foaming agent, a foaming aid and a nonionic surfactant. Therefore, the water stopping property is good.

Moreover, the elongation percentage of the EPDM foam is 300% or more and 1000% or less. Therefore, EPDM can be brought into close contact with the shape and unevenness of the adherend that is various members, and the gaps between the various members can be reliably sealed.

Therefore, this EPDM foam can reliably prevent water from entering in the gaps between the various members.

The EPDM foam is preferably obtained by foaming a rubber composition further containing an aromatic sulfinic acid compound. Therefore, fogging can be suppressed while improving flexibility.

FIG. 1 is a schematic configuration diagram showing an embodiment of a sealing material of the present invention.

That is, in FIG. 1, the sealing material 1 includes the above-described EPDM foam 2 and an adhesive layer 3 provided on one surface (surface) of the EPDM foam 2.

The adhesive layer 3 is formed from, for example, a known adhesive.

Examples of adhesives include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, polyamide adhesives, epoxy adhesives, vinyl alkyl ether adhesives, fluorine System adhesives and the like. Examples of the pressure sensitive adhesive include hot melt pressure sensitive adhesive. These pressure-sensitive adhesives can be used alone or in combination of two or more.

As the pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive and a rubber-based pressure-sensitive adhesive are preferable.

The acrylic pressure-sensitive adhesive is, for example, a pressure-sensitive adhesive mainly composed of (meth) acrylic alkyl ester, and can be obtained by a known method.

The rubber-based pressure-sensitive adhesive can be obtained by a known method from, for example, natural rubber and / or synthetic rubber, specifically, rubber such as polyisobutylene rubber, polyisoprene rubber, chloroprene rubber, butyl rubber, and nitrile butyl rubber.

The form of the pressure-sensitive adhesive is not particularly limited, and various forms such as an emulsion-based pressure-sensitive adhesive, a solvent-based pressure-sensitive adhesive, an oligomer-based pressure-sensitive adhesive, and a solid pressure-sensitive adhesive can be employed.

The thickness of the pressure-sensitive adhesive layer 3 is, for example, 10 μm or more, preferably 50 μm or more, and for example, 10,000 μm or less, preferably 5000 μm or less.

The method for forming the sealing material 1 is not particularly limited, and a known method can be employed. Specifically, for example, the adhesive layer 3 is laminated on the surface of the EPDM foam 2 by a known method.

And according to such a sealing material 1, since it has the EPDM foam 2 with good water-stopping properties, the EPDM 2 can be easily adhered to the member, and the gaps between the various members can be reliably sealed. it can.

Further, in the embodiment of FIG. 1, the adhesive layer 3 is provided only on one surface of the EPDM foam 2, but although not illustrated, for example, the adhesive layer 3 is provided on both surfaces (front surface and back surface) of the EPDM foam 2. It can also be provided.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In addition, this invention is not limited to an Example and a comparative example at all. Specific numerical values such as blending ratio (content ratio), physical property values, and parameters used in the following description are described in the above-mentioned “Mode for Carrying Out the Invention”, and the corresponding blending ratio (content ratio) ), Physical property values, parameters, etc. The upper limit value (numerical value defined as “less than” or “less than”) or lower limit value (number defined as “greater than” or “exceeded”) may be substituted. it can.

Examples 1 to 6 and Comparative Examples 1 to 5
(1) Manufacture of EPDM Foam EPDM, foaming agent, foaming aid, softening agent, filler, processing aid and pigment are blended in the blending amounts shown in the blending prescription shown in Table 1 into a 3 L pressure kneader. And kneaded to prepare a primary mixture.

Separately, a crosslinking agent, a crosslinking accelerator, a surfactant, an aromatic sulfinic acid compound, a basic metal compound, and the like are blended, blended into a primary blend, kneaded with a 10 inch mixing roll, and a rubber composition. (Secondary mixture) was prepared (kneading step).

Next, the rubber composition was extruded into a sheet having a thickness of about 8 mm using a single screw extruder (45 mmφ) to produce a rubber composition sheet (molding step).

Subsequently, the rubber composition sheet was preheated at 140 ° C. for 20 minutes in a hot air circulating oven. Thereafter, the temperature was raised to 180 ° C. in a hot air circulation oven over 11 minutes, and the rubber composition sheet was heated at 180 ° C. for 10 minutes to be foamed (foaming step) to produce an EPDM foam.

(2) Physical property measurement Each physical property of the EPDM foam of each Example and each comparative example was measured by the method shown below. The results are shown in Table 1.

<Apparent density>
The apparent density of the EPDM foam was measured according to JIS K 6767 (1999). Specifically, the skin layer of the EPDM foam was removed to prepare a test piece having a thickness of about 10 mm. Then, mass was measured and the mass per unit volume (apparent density) was computed.

<50% compression load value>
The compression load value of the EPDM foam was measured according to JIS K 6767 (1999). Specifically, the skin layer of the EPDM foam was removed to prepare a test piece having a thickness of about 10 mm. Thereafter, the compression load value was measured 10 seconds after 50% compression at a compression speed of 10 mm / min using a compression tester.

<Tensile strength and elongation>
The tensile strength and elongation of the EPDM foam were measured according to JIS K 6767 (1999). Specifically, the skin layer of the EPDM foam was removed to prepare a test piece having a thickness of about 10 mm. Then, using the dumbbell No. 1, the test piece was punched out to obtain a measurement sample. With a tensile tester, the measurement sample was pulled at a pulling speed of 500 mm / min, and the load (tensile strength) and elongation (breaking elongation) when the measurement sample was cut at the dumbbell-shaped parallel portion were measured.

<Foging properties>
The skin layer of the EPDM foam was removed to prepare a test piece having a length of 100 mm, a width of 50 mm, and a thickness of 10 mm. Thereafter, a test piece was placed on the bottom of a glass bottle having an opening inner diameter of 40 mm, a bottom inner diameter of 70 mm, and a height of 160 mm, and the glass bottle was immersed in a 100 ° C. silicone oil bath (oil depth 110 mm). Next, a glass plate was placed in the opening of the glass bottle to cover the opening and left for 20 hours. After being allowed to stand, the mass of the glass plate was measured, and the amount of increase in the mass with respect to the glass plate before being left was measured.

<70% water-stop test>
An outline of the 70% water-stop test is shown in FIG. The EPDM foam sample 2 was punched into a U shape with a thickness of 10 mm, a width of 10 mm, a height of 148 mm, and a distance between both ends of 54 mm. The sample 2 was bolted 7 with a spacer 6 via an acrylic plate 4 and an aluminum plate 5 and compressed in the thickness direction by 70% (that is, compressed until the thickness of the sample 2 became 3 mm). Water 8 was put in a U-shape of sample 2 to a height of 100 mm, and the time until water leakage was measured. When there is a water leak in less than 1 hour, “X”, when there is a water leak within 1 to 12 hours, “△”, and when there is no water leak after 12 hours, “○” ".

<80% water-stop test>
Except that the EPDM foam sample 2 was compressed by 80% in the thickness direction, it was carried out in the same manner as the 70% water-stop test, and the time until water leakage was measured. When there is a water leak in less than 1 hour, “X”, when there is a water leak within 1 to 12 hours, “△”, and when there is no water leak after 12 hours, “○” ".

The numerical values in Table 1 indicate the number of parts by mass in each component. Details of the abbreviations described in Table 1 are shown below. Details of other general components are omitted.
EPT8030M: long chain branched structure content (η ^* (Γ = 0.15) / η ^* (Γ = 17.5) = 11.3), diene (5-ethylidene-2-norbornene) content 9.5 mass %, Catalyst: metallocene catalyst, 32 (ML (1 + 4) 100 ° C.), manufactured by Mitsui Chemicals, EP24: diene (5-ethylidene-2-norbornene) content 4.5% by mass, manufactured by JSR, ADCA: azodicarbon Amide-blown asphalt: "Trumbll Base Asphalt 4402", asphalt, manufactured by Trumbll, Sulfur: "Alphagran S-50EN", sulfur masterbatch, manufactured by Tochi Co., Ltd. thiazoles: 2-mercaptobenzothiazole
・ Dithiocarbamate: Zinc dibenzyldithiocarbamate ・ Ethylenebisstearic acid amide: “Alflow H-50TF”, nonionic surfactant, manufactured by NOF Corporation ・ Stearic acid monoamide: “Alflow S-10”, nonionic Surfactant, manufactured by NOF Corporation, polyoxyethylene monostearate: “Nonion S-15”, nonionic surfactant, manufactured by NOF Corporation: ethylene glycol distearate: “Unistar E-275”, nonionic Surfactant, manufactured by NOF Corporation, calcium stearate: “SC-P”, cationic surfactant, manufactured by Sakai Chemical Co., Ltd., polyethylene glycol: “PEG 4000”, manufactured by Sanyo Chemical Industries, Ltd., bis-p-toluenesulfinic acid Zinc: “Cell Paste P”, manufactured by Eiwa Kasei Co., Ltd. Calcium oxide: “CML # 31”, Omi Chemical Co., Ltd. The above invention has been provided as illustrative embodiments of the present invention, this is merely illustrative and should not be construed restrictively. Variations of the present invention apparent to those skilled in the art are included within the scope of the following claims.

The ethylene-propylene-diene rubber foam and the sealing material of the present invention can be applied to various industrial products, for example, suitable for a sealing material that seals gaps of various members such as automobile use, housing use use, and home appliance use. Can be used.

1 Sealing material 2 EPDM foam 3 Adhesive layer

Claims (8)

1. It is obtained by foaming a rubber composition containing an ethylene / propylene / diene rubber, a crosslinking agent, a crosslinking accelerator, a foaming agent, a foaming aid and a nonionic surfactant,
   Elongation rate is 300% or more and 1000% or less, an ethylene / propylene / diene rubber foam.
2. The ethylene-propylene-diene rubber foam according to claim 1, wherein the nonionic surfactant is a fatty acid amide.
3. 2. The ethylene / propylene according to claim 1, wherein a content ratio of the nonionic surfactant is 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the ethylene / propylene / diene rubber. -Diene rubber foam.
4. The ethylene / propylene / diene rubber foam according to claim 1, wherein the rubber composition further contains an aromatic sulfinic acid compound.
5. 5. The ethylene / propylene according to claim 4, wherein a content ratio of the aromatic sulfinic acid compound is 10 parts by mass or more and 300 parts by mass or less with respect to 100 parts by mass of the nonionic surfactant. -Diene rubber foam.
6. Apparent density, and equal to or less than 0.050 g / cm ³ or more 0.200 g / cm ^3, ethylene-propylene-diene rubber foamed material according to claim 1.
7. ^2. The ethylene / propylene / diene rubber foam according to claim 1, wherein a 50% compressive load is 0.1 N / cm ² or more and 2.0 N / cm ² or less.
8. A sealing material for filling a gap between members,
   The ethylene-propylene-diene rubber foam according to claim 1;
   An adhesive layer provided on at least one surface of the ethylene / propylene / diene rubber foam.

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