JP3365670B2 - Ethylene / propylene rubber composition for vulcanized rubber - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ethylene / propylene rubber composition for vulcanized rubber , and more specifically, a vulcanized rubber that can be effectively used for applications such as automobile interior materials and sealing materials.
High hardness ethylene-propylene rubber composition for use in rubber.

[0002]

BACKGROUND OF THE INVENTION Various high hardness rubber products used for automobiles are manufactured by a molding method such as extrusion molding. For example, a rubber composition used as a raw material for a high-hardness extruded rubber product manufactured by an extrusion molding method has excellent mechanical properties such as hardness, strength and elongation of the rubber product obtained from the rubber composition, and also has good processability and economical efficiency. It is required to have excellent properties. Here, this processability is evaluated by the Mooney viscosity, which is an index of fluidity, and the strength (eg, green strength) of the unvulcanized rubber.

As a rubber composition satisfying such requirements, an ethylene / propylene rubber composition in which polyethylene is mixed with ethylene / propylene rubber is known. However, this ethylene-propylene rubber composition,
The addition of polyethylene provides a good balance between economic efficiency and the above mechanical properties, but there is a problem in that the dispersibility of polyethylene during kneading is poor.

Therefore, in order to solve this problem, the use of polyethylene having a low melting point of 115 ° C. or less was studied, but polyethylene having a low melting point can only provide a vulcanized rubber having a low mechanical strength. There was a problem.

Therefore, it has been desired from the past to provide an ethylene / propylene rubber composition for vulcanized rubber , which has an excellent balance of processability and mechanical properties of rubber products, and which is excellent in kneading property and can be produced at low cost. ing.

[0006]

SUMMARY OF THE INVENTION The present invention is intended to solve the problems associated with the prior art as described above, and has a good balance of processability and mechanical properties of rubber products, and a low kneading property. It is an object of the present invention to provide an ethylene / propylene rubber composition for vulcanized rubber, which can achieve cost reduction.

[0007]

SUMMARY OF THE INVENTION The ethylene / propylene rubber composition for vulcanized rubber according to the present invention is an ethylene / propylene rubber (A).
100 parts by weight and 5 to 40 parts by weight of polyethylene (B), the polyethylene (B) is a copolymer of (1) ethylene and an α-olefin having 4 to 8 carbon atoms, 2) The content of α-olefin having 4 to 8 carbon atoms is 10 to 3.
0% by weight, (3) specific gravity is 0.900 to 0.915, (4) melting point measured by DSC is in the range of 90 to 115 ° C., and (5) measured by X-ray method. The crystallinity is in the range of 20 to 50%.

The ethylene-propylene rubber (A) preferably used in the present invention has a Mooney viscosity [ML _{1 + 4} (10
0 ° C.)] is 50 to 250 and the ethylene content is 65 to
It is an ethylene / propylene / non-conjugated diene copolymer rubber having 80 mol% and an iodine value of 5 to 40.

Ethylene / propylene rubber set according to the present invention
Preferred Mooney viscosity of product [ML _{1 + 4} (100 ° C)]
Is in the range of 10 to 80.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The ethylene / propylene rubber composition for vulcanized rubber according to the present invention will be specifically described below.

The ethylene / propylene rubber composition for vulcanized rubber according to the present invention is an ethylene / propylene rubber (A).
And a specific polyethylene (B) in a specific ratio. Ethylene / Propylene Rubber (A) Examples of the ethylene / propylene rubber (A) used in the present invention include ethylene / propylene copolymer rubber and ethylene / propylene / non-conjugated diene copolymer rubber.

Specific examples of the non-conjugated diene constituting the ethylene / propylene / non-conjugated diene copolymer rubber include ethylidene norbornene, dicyclopentadiene, 1,4-hexadiene, methylene norbornene, methyl octadiene and vinyl. Examples include norbornene.

The ethylene / propylene copolymer rubber preferably has an ethylene content of 65 to 80 mol%, more preferably 70 to 80 mol%, and a Mooney viscosity [ML 1 _{+ 4} (100 ° C.)] of preferably. 50-250,
More preferably, it is 70-120.

The ethylene / propylene / non-conjugated diene copolymer rubber preferably has an ethylene content of 65.
To 80 mol%, more preferably 70 to 80 mol%, iodine value is preferably 5 to 40, more preferably 10 to 25, and Mooney viscosity [ML _{1 + 4} (100
C)] is preferably 50 to 250, more preferably 70 to 120.

Polyethylene (B) The polyethylene (B) used in the present invention is a copolymer composed of ethylene and an α-olefin having 4 to 8 carbon atoms.

Specific examples of the α-olefin having 4 to 8 carbon atoms include 1-butene, 4-methyl-1-pentene, 1-hexene and 1-octene. Of these, 1-butene is preferable.

Polyethylene (B) used in the present invention
Has an α-olefin content of 4 to 8 carbon atoms of 10 to 3
It is 0% by weight, preferably 10 to 20% by weight, more preferably 15 to 20% by weight.

The specific gravity of polyethylene (B) is 0.9
00 to 0.915, preferably 0.900 to 0.910
And more preferably 0.905 to 0.910. The polyethylene (B) used in the present invention is DSC.
The melting point measured by (differential scanning calorimetry) is in the range of 90 to 115 ° C.

The crystallinity of polyethylene (B) measured by the X-ray method is 20 to 50%, preferably 20 to 50%.
It is in the range of 30%. Polyethylene (B) melt flow rate (MFR, ASTM D 1238, 190 ° C,
Load 2.16 kg) is usually 0.1 to 20 g / 10 minutes,
Preferably 1 to 10 g / 10 minutes, more preferably 2 to
It is in the range of 5 g / 10 minutes.

In the present invention, polyethylene (B)
Is used in an amount of 5 to 40 parts by weight, preferably 10 to 30 parts by weight, and more preferably 15 to 20 parts by weight with respect to 100 parts by weight of the ethylene / propylene rubber (A).

In the present invention, when the polyethylene (B) having the above characteristics is used in the above proportions,
The obtained ethylene / propylene rubber composition is excellent in the processability and the balance of the mechanical properties of the rubber product, and also in the kneading property.

The ethylene / propylene rubber composition of the present invention comprising the above ethylene / propylene rubber (A) and polyethylene (B) has a Mooney viscosity [M
L _{1 + 4} (100 ° C.)] is preferably in the range of 10 to 80, more preferably 30 to 50.

The ethylene / propylene rubber composition for vulcanized rubber according to the present invention is vulcanized before use . The vulcanization of the ethylene / propylene rubber composition according to the present invention is carried out by preparing an unvulcanized compounded rubber once, and then forming this compounded rubber into an intended shape, as in the case of vulcanizing a general rubber. It is performed after molding.

Vulcanization of the ethylene / propylene rubber composition according to the present invention is usually carried out using a vulcanizing agent. Examples of the vulcanizing agent include sulfur, organic peroxides, polyfunctional amines, polyols and triazine compounds.

Examples of sulfur include pure sulfur, modified sulfur, and sulfur compounds that release active sulfur atoms in the vulcanization step. In the present invention, sulfur is added to 100 parts by weight of the ethylene / propylene rubber (A).
It is used in a proportion of 0.1 to 10 parts by weight, preferably 0.5 to 3.0 parts by weight.

Specific examples of the organic peroxide include dicumyl peroxide, di-tert-butyl peroxide, and 2,5-
Dimethyl-2,5-di- (tert-butylperoxy) hexane, 2,5-Dimethyl-2,5-di- (tert-butylperoxy)
Hexine-3,1,3-bis (tert-butylperoxyisopropyl) benzene, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4
-Bis (tert-butylperoxy) valerate, benzoyl peroxide, p-chlorobenzoyl peroxide,
2,4-dichlorobenzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl perbenzoate, tert-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, tert-butyl cumyl peroxide and the like can be mentioned.

In the present invention, the organic peroxide is used in a proportion of 0.5 to 10 parts by weight, preferably 1.0 to 4.0 parts by weight, based on 100 parts by weight of the ethylene / propylene rubber (A). .

When sulfur is used as the vulcanizing agent, it is preferable to use a vulcanization accelerator together. As the vulcanization accelerator, specifically, N-cyclohexyl-2-benzothiazole sulfenamide, N-oxydiethylene-2-benzothiazole sulfenamide, N, N-diisopropyl
-2-Benzothiazole sulfenamide, 2-mercaptobenzothiazole, 2- (2,4-dinitrophenyl) mercaptobenzothiazole, 2- (2,6-diethyl-4-morpholinothio) benzothiazole, dibenzothiazyl disulfide Thiazole compounds such as diphenylguanidine,
Guanidine compounds such as triphenylguanidine, diorsonitrile guanidine, orthonitrile biguanide, diphenylguanidine phthalate; acetaldehyde-aniline reaction products, butyraldehyde-aniline condensates, hexamethylenetetramine, aldehyde amines such as acetaldehyde ammonia, or aldehyde-ammonia. -Based compounds; imidazoline-based compounds such as 2-mercaptoimidazoline; thiourea-based compounds such as thiocarbanilide, diethylthiourea, dibutylthiourea, trimethylthiourea, diorsotolylthiourea; tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethyl Thiuram disulfide, tetrabutyl thiuram disulfide, pentamethylene thiuram tetrasulfide Thiuram compounds; zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc di-n-butyldithiocarbamate, zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, selenium dimethyldithiocarbamate, tellurium dimethyldithiocarbamate. Examples thereof include dithioate-based compounds such as: xanthate-based compounds such as zinc dibutylxanthate; compounds such as zinc white. These vulcanization accelerators are used in an amount of 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of ethylene-propylene rubber (A).
Used in proportions by weight.

When an organic peroxide is used as a vulcanizing agent, it is preferable to use a vulcanizing auxiliary together. Specific examples of the vulcanization 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; Other examples include maleimide compounds; divinylbenzene and the like. Such a vulcanization aid is used in an amount of 0.5 to 2 mol, preferably about equimolar, relative to 1 mol of the organic peroxide used.

In the ethylene / propylene rubber composition according to the present invention, in addition to the above ethylene / propylene rubber (A), polyethylene (B), vulcanizing agent and vulcanization accelerator or vulcanization aid, a car A reinforcing material such as bonblack is added to 100 parts by weight of the above ethylene / propylene rubber (A).
It is desirable to use it in an amount of from 400 to 400 parts by weight, preferably from 50 to 200. When the reinforcing material is used in the above proportion, an ethylene / propylene rubber composition having high strength can be obtained.

As such a reinforcing material, specifically,
In addition to carbon black, silica, clay, calcium carbonate, etc. may be mentioned. Further, ethylene according to the present invention
An inexpensive extender may be added to the propylene rubber composition in order to reduce the compounding cost of the rubber. That is, if a large amount of the filler is added, the resulting ethylene / propylene rubber composition will be low in cost and excellent in economic efficiency.

Specific examples of such an extender include:
Examples include heavy calcium carbonate, light calcium carbonate, and clay. A filler such as clay may also serve as a reinforcing material.

In the present invention, the extender is ethylene.
Usually 10 to 100 parts by weight of propylene rubber (A)
300 parts by weight, preferably 10-200 parts by weight, more preferably 20-100 parts by weight, particularly preferably 40-
Used in a proportion of 80 parts by weight.

It is desirable to add a softening agent to the ethylene-propylene rubber composition according to the present invention in order to improve processability. As the softening agent, various mineral oils which are usually used as process oils in rubber, for example, paraffinic, naphthenic, and aromatic mineral oils, synthetic hydrocarbon oils, polyglycol oils, polyphenyl ether oils, ester oils, phosphate ester oils. , Polychlorotrifluoroethylene oil, fluoroester oil, chlorinated biphenyl oil, silicone oil and the like are used.

Among the above-mentioned softening agents, paraffin type process oil or naphthene type process oil is preferably used in an amount of about 20 to 100 parts by weight based on 100 parts by weight of the ethylene-propylene rubber (A).

Further, in the ethylene / propylene rubber composition according to the present invention, if necessary, additives such as a heat resistance stabilizer, an antistatic agent, a weather resistance stabilizer, an antiaging agent, a coloring agent and a lubricant may be added. It can be blended within a range that does not impair the object of the invention.

The unvulcanized compounded rubber is prepared, for example, by the following method. That is, after the above ethylene / propylene rubber (A), polyethylene (B), reinforcing material, extender and softening agent are kneaded at a temperature of 80 to 170 ° C. for 3 to 10 minutes with a mixer such as a Banbury mixer, and then opened. A roll such as a roll is used to additionally mix a vulcanizing agent and, if necessary, a vulcanization accelerator or a vulcanization aid, and the mixture is kneaded at a roll temperature of 40 to 80 ° C. for 5 to 30 minutes and then dispensed. A ribbon-shaped or sheet-shaped compounded rubber is prepared.

The compounded rubber prepared as described above is
The vulcanized product is molded into an intended shape by an extruder, a calender roll or a press, and simultaneously with molding or by introducing the molded product into a vulcanization tank and heating at a temperature of 150 to 270 ° C. for 1 to 30 minutes. can get. A mold may be used in this vulcanization step, or vulcanization may be carried out without using a mold. When a mold is not used, the molding and vulcanization steps are usually carried out continuously. As a heating method in the vulcanization tank, a heating tank such as hot air, a fluidized bed of glass beads, UHF (ultra high frequency electromagnetic wave), or steam can be used.

[0039]

The ethylene / propylene rubber composition for vulcanized rubber according to the present invention contains ethylene / propylene rubber and a specific polyethylene in a specific ratio. Therefore, the processability and the hardness and strength of the rubber product are improved. Excellent balance of mechanical properties such as elongation.

Further , the ethylene / propylene rubber composition for vulcanized rubber in the present invention has remarkably excellent kneading property as compared with the conventional rubber compounded with polyethylene, and is reduced by adding an extender or a reinforcing material. Cost can be reduced.

Therefore, the above-mentioned effect is obtained.
INDUSTRIAL APPLICABILITY The ethylene / propylene rubber composition for vulcanized rubber according to the present invention can be effectively used for automobile interior materials and sealing materials (such as glass run channels).

The present invention will be described below with reference to examples.
The present invention is not limited to these examples.

[0043]

Example 1 Ethylene content 70 mol%, iodine value 12,
100 parts by weight of ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber [hereinafter referred to as EPDM] having a Mooney viscosity [ML _{1 + 4} (100 ° C.)] of 100, and ethylene and 1-butene Combined, 1-butene content 1
5% by weight, melting point 106 ° C., specific gravity 0.905, MFR (A
(STM D 1238, 190 ° C, load 2.16 kg)
2.2 g / 10 min, crystallinity 25 measured by X-ray method
% Polyethylene [hereinafter abbreviated as polyethylene (1)]
20 parts by weight, 1 part by weight of stearic acid, 5 parts by weight of zinc white, FEF carbon black [manufactured by Asahi Carbon Co., Ltd.,
Product name: Asahi 60] 150 parts by weight, paraffin oil [manufactured by Idemitsu Kosan Co., Ltd., product name: Diana Process Oil PW-380] 80 parts by weight, and calcium oxide 5 parts by weight using a Banbury mixer, Kneading was performed at 150 ° C. for 5 minutes.

Then, the kneaded product thus obtained was mixed with 1.5 parts by weight of sulfur as a vulcanizing agent and MBT as a vulcanization accelerator [trade name: NOXCELLER M, Shin Ouchi Shinko] per 100 parts by weight of EPDM. Chemical Industry Co., Ltd.] 1.5 parts by weight, TeEDC [Product Name: Nox Cellar TTTE, Ouchi Shinko Chemical Industry Co., Ltd.] 0.5 parts by weight, ZnBDC [Product Name: Nox Cellar BZ, Ouchi Shinko Chemical Industry] Co., Ltd.]
5 parts by weight, 0.5 parts by weight of EU [trade name: Suncellar 22, manufactured by Sanshin Chemical Industry Co., Ltd.] and 0.5 parts by weight of DPTT [trade name: Noxceller TRA, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.] Is added with a mixing roll, and the compound (a-
1) was obtained.

Mooney viscosity of the obtained compound (a-1) [ML _{1 + 4} (100 ° C., JIS K 6300)]
Was 30. In addition, the above EPDM, polyethylene (1), stearic acid, zinc white, FEF carbon black, paraffin oil and calcium oxide were mixed in the above proportions using a Banbury mixer at 150 ° C.
Kneading was carried out for a minute to obtain a compound (a-2).

The physical properties of the vulcanized rubber were measured according to the following methods using the compound (a-1) obtained as described above, and the compound (a-2) obtained as described above was used. The green strength and kneadability were measured according to the following methods. (1) Measurement of Green Strength The above compound (a-2) was molded into a sheet using an open roll heated under the following conditions, and this compound was pressed at 50 ° C. for 5 minutes using a press molding machine. Then, an unvulcanized rubber sheet having a thickness of 2 mm was obtained. The tensile strength (tensile breaking point stress) of this sheet was determined and defined as the green strength (kg / cm ² ).

Conditions for heating as described above: Roll temperature = 50 ° C. Roll gap = 2 mm Tensile strength: Measured by a vulcanized rubber test method defined in JIS K6301. (2) Measurement of physical properties of vulcanized rubber Using the press vulcanizer, the compound (a-1)
It was vulcanized at 60 ° C. for 10 minutes to obtain a vulcanized rubber sheet having a thickness of 2 mm. The hardness of the sheet (JIS A hardness), tensile strength (tensile stress at break, T _B), elongation (E _B) JIS
It was measured by the vulcanized rubber test method specified in K 6301. (3) Measurement of kneading property The compound (a-2) was formed into a sheet having a thickness of 0.1 mm by an open roll, and the number of undispersed polyethylenes in a 10 cm square was measured.

The results are shown in Table 1.

[0049]

Comparative Example 1 Compound (b-1) and compound (b-2) were obtained in the same manner as in Example 1 except that polyethylene (1) was not used.

Using the compound (b-1) obtained as described above, the physical properties of the vulcanized rubber were measured according to the methods described above, and the compound (b-2) obtained as described above was used. Green strength and kneadability were measured according to the methods described above.

The results are shown in Table 1.

[0052]

Comparative Example 2 In Example 1, instead of polyethylene (1), ethylene content was 100 mol%, melting point was 106.
° C, specific gravity 0.908, MFR (ASTM D 1238,
Except for using high-pressure polyethylene (hereinafter abbreviated as polyethylene (2)) having a crystallinity of 0% measured by X-ray method at 190 ° C., load 2.16 kg) 2.0 g / 10 min.
In the same manner as in Example 1, a compound (c-1) and a compound (c-2) were obtained.

Using the compound (c-1) obtained as described above, the physical properties of the vulcanized rubber were measured according to the methods described above, and the compound (c-2) obtained as described above was used. Green strength and kneadability were measured according to the methods described above.

The results are shown in Table 1.

[0055]

COMPARATIVE EXAMPLE 3 In Example 1, instead of polyethylene (1), a copolymer of ethylene and 1-butene was used.
1-butene content 6% by weight, melting point 122 ° C, specific gravity 0.92
0, MFR (ASTM D 1238, 190 ° C., load 2.16 kg) 2.1 g / 10 minutes, except that polyethylene having a crystallinity of 38% measured by X-ray [hereinafter abbreviated as polyethylene (3)] was used. In the same manner as in Example 1, compound (d-1) and compound (d-
2) was obtained.

Using the compound (d-1) obtained as described above, the physical properties of the vulcanized rubber were measured according to the above-mentioned methods, and the compound (d-2) obtained as described above was used. Green strength and kneadability were measured according to the methods described above.

The results are shown in Table 1.

[0058]

[Table 1]

Claims (6)

(57) [Claims] 1. An ethylene / propylene rubber (A) comprising 100 parts by weight and polyethylene (B) comprising 5 to 40 parts by weight, wherein the polyethylene (B) comprises: (1) ethylene and α having 4 to 8 carbon atoms. -A copolymer of olefin and (2) the content of α-olefin having 4 to 8 carbon atoms is 10 to 3
0% by weight, (3) specific gravity is 0.900 to 0.915, (4) melting point measured by DSC is in the range of 90 to 115 ° C., and (5) measured by X-ray method. An ethylene / propylene rubber composition for vulcanized rubber having a crystallinity in the range of 20 to 50%. 2. The ethylene / propylene rubber (A) comprises:
Mooney viscosity [ML _{1 + 4} (100 ° C)] is 50-250
Ethylene ethylene having a content of 65 to 80 mol% and an iodine value of 5 to 40.
The ethylene / propylene rubber composition for vulcanized rubber according to claim 1, which is a non-conjugated diene copolymer rubber. 3. The ethylene / propylene rubber (A) 10
The ethylene / propylene rubber composition for vulcanized rubber according to claim 1 or 2, wherein the reinforcing material is contained in an amount of 20 to 400 parts by weight with respect to 0 parts by weight. 4. The ethylene / propylene rubber (A) 10
The ethylene / propylene rubber composition for vulcanized rubber according to any one of claims 1 to 3, wherein the softening agent is contained in an amount of 20 to 100 parts by weight relative to 0 parts by weight. 5. The vulcanized rubber according to claim 1, wherein the ethylene-propylene rubber composition has a Mooney viscosity [ML _{1 + 4} (100 ° C.)] of 10 to 80. Ethylene / propylene rubber composition. 6. The ethylene / propylene rubber composition for vulcanized rubber according to claim 1, further containing a vulcanizing agent.