JP2001316487A - Thermoplastic olefin elastomer and its use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic olefin elastomer which is excellent in rubber elasticity, especially low-temperature rubber elasticity, and can give an automotive sealing part excellent in sealing properties, especially low- temperature sealing properties. SOLUTION: This elastomer has a gel content of 80% or higher and gives a molded item having a tensile strength of 3.0 MPa or higher, an elongation at break of 250% or higher, and a compression set (-30 deg.C, 24 h) of 65% or lower. Preferably, the elastomer is thermoplastic elastomer composition which is obtained by dynamically thermally treating a mixture containing (A) an ethylene/α-olefin/nonconjugated polyene terpolymer having a molar ratio of ethylene to a 3-20C α-olefin of (55/45)-(70/30) and (B) an olefin resin in a specified ratio in the presence of a crosslinker. The automotive sealing part is prepared from the elastomer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an olefinic thermoplastic elastomer excellent in rubber elasticity, particularly rubber elasticity at low temperature, and its use.

[0002]

BACKGROUND OF THE INVENTION Vulcanized rubber has excellent flexibility and rubber elasticity, but has problems in moldability. For example, in the case of injection molding, it can be obtained by compounding and kneading additives to rubber. Since the kneaded material needs to be vulcanized after being supplied into the mold, a special molding machine is required, the molding cycle time is long, and the process is complicated. Extrusion molding also has a similar problem, which is a problem in mass-producing vulcanized rubber products. In addition, the vulcanized rubber does not melt even if reheated after being molded and vulcanized once, so that there is a problem that post-processing such as joining cannot be performed.

[0003] From these points, in recent years, thermoplastic elastomers have been used in place of vulcanized rubbers.
The use of olefin-based thermoplastic elastomers has been increasing from the viewpoints of environmental pollution resistance and economy.

However, conventional olefin-based thermoplastic elastomers have insufficient rubber elasticity, especially at low temperatures, as compared with vulcanized rubber, and improvement thereof is desired.

[0005] Further, in a vehicle of an automobile, various seal parts such as a glass run channel, a weather strip, various boots, and a draining molding are used. Most of them use vulcanized rubber, but from the viewpoint of improving fuel efficiency and environmental issues, in recent years, lightweight and recyclable olefin-based thermoplastic elastomers have begun to be used as part of the sealing parts.

[0006] However, conventional olefin-based thermoplastic elastomers have the disadvantage that rubber elasticity, tensile strength and elongation at break are inferior to vulcanized rubber. In particular, when rubber elasticity is inferior, sealing performance, which is the most important performance as a sealing part, is inferior, and this is a major problem, and the improvement in rubber elasticity of olefin-based thermoplastic elastomers, especially in the low temperature range, is strong. It has been demanded.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems associated with the prior art as described above, and it is an object of the present invention to produce a molded article having excellent sealing properties, especially low-temperature sealing properties, for example, a sealing part for automobiles. It is an object of the present invention to provide an olefin-based thermoplastic elastomer which is excellent in rubber elasticity, particularly rubber elasticity at low temperature, and a sealing part for automobiles.

[0008]

The olefin-based thermoplastic elastomer according to the present invention is an olefin-based thermoplastic elastomer having a gel content of 80% or more, and a molded product obtained by molding the olefin-based thermoplastic elastomer has a tensile strength. (JIS K-6251) is 3.0 MPa or more, elongation at break (JIS K-6251) is 250% or more, and JIS
It is characterized by having a compression set of 65% or less measured at -30 ° C for 24 hours based on the K6262 method.

The olefin-based thermoplastic elastomer includes (A) ethylene and an α-olefin having 3 to 20 carbon atoms.
Consisting of olefin and non-conjugated polyene, ethylene and α
-Molar ratio with olefin (ethylene / α-olefin)
40-85 parts by weight of an ethylene / α-olefin / non-conjugated polyene copolymer rubber which may be oil-extended, and 55 / 45-70 / 30, and (B) an olefin resin 15
６０60 parts by weight [the total amount of the component (A) and the component (B) is 1
00 parts by weight, and when the component (A) is oil-extended, the 40 to 85 parts by weight is ethylene.
Shows the compounding amount of the olefin / non-conjugated polyene copolymer rubber. And the thermoplastic elastomer composition obtained by dynamically heat-treating the mixture containing the crosslinking agent in the presence of a crosslinking agent.

[0010] The ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) (when the ethylene / α-olefin / non-conjugated polyene copolymer (A) is oil-extended, Of ethylene / α-olefin / non-conjugated polyene copolymer rubber) [ML _{1 + 4} (10
0 ° C.)] is preferably in the range of 100 to 160.

The olefin-based thermoplastic elastomer according to the present invention is prepared by previously blending the entire amount of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and the entire amount of the olefin-based resin (B) in a molten state. The pellets and the cross-linking agent prepared as described above are charged into a twin-screw extruder and dynamically heat-treated, and the above-mentioned ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) The pellets prepared by previously blending the whole amount of the olefin resin (B) and a part of the olefin resin (B) in a molten state, the remaining pellets of the olefin resin (B), and a cross-linking agent are charged into a twin-screw extruder. It can also be obtained by performing a thermal treatment.

[0012] An automotive seal part according to the present invention is characterized by comprising the above-mentioned olefinic thermoplastic elastomer according to the present invention.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The olefin-based thermoplastic elastomer according to the present invention and its use will be specifically described below.

The olefinic thermoplastic elastomer according to the present invention has a gel content of at least 80%, preferably at least 90%, more preferably at least 95%, and is a molded article obtained by molding the olefinic thermoplastic elastomer. Has a tensile strength (JIS K-6251) of 3.0 MPa or more, usually 3.0
-25 MPa, preferably 3.5-20 MPa, more preferably 4.0-15 MPa or more, and elongation at break (JIS K-6251) of 250% or more, usually 250-1000.
%, Preferably 270-800%, more preferably 30%
0 to 700%, and a compression set of not more than 65%, usually 65 to 10%, preferably 60 to 60% measured at -30 ° C for 24 hours based on JIS K6262 method.
20%, more preferably 55 to 30%. The olefin-based thermoplastic elastomer having such properties is
It is suitable for applications such as automotive seal parts.

As the olefin-based thermoplastic elastomer, specifically, (A) ethylene and a compound having 3 carbon atoms
Consisting of an α-olefin of ~ 20 and a non-conjugated polyene,
The molar ratio of ethylene to α-olefin (ethylene / α-olefin
(Olefin) is 55 / 45-70 / 30, and 40-85 parts by weight of an ethylene / α-olefin / non-conjugated polyene copolymer rubber which may be oil-extended, and (B) an olefin resin (B) 60 A thermoplastic elastomer composition obtained by dynamically heat-treating a mixture containing 15 parts by weight [the total amount of the components (A) and (B) is 100 parts by weight] in the presence of a crosslinking agent. Is preferred.

Ethylene / α-olefin / non-conjugated polyether
The ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) used in the present invention comprises ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated polyene. An amorphous random elastic copolymer rubber having a molar ratio of ethylene to an α-olefin having 3 to 20 carbon atoms [ethylene / α-olefin] of 55/45 to 70/30. Among them, ethylene / α in which the molar ratio of ethylene to α-olefin is 60/40 to 70/30
-Olefin / non-conjugated polyene copolymer rubber (A) is particularly preferred.

The composition of the ethylene / α-olefin / non-conjugated polyene copolymer rubber is usually about 200 mg of the ethylene / α-olefin / non-conjugated polyene copolymer rubber in 1 ml of hexachlorobutadiene in a 10 mmφ sample tube. The ¹³ C-NMR spectrum of a sample dissolved in is measured at a measurement temperature of 120 ° C., a measurement frequency of 25.05 MHz, a spectrum width of 1500 Hz, a pulse repetition time of 4.2 sec., And a pulse width of 6 μsec. .

As the α-olefin having 3 to 20 carbon atoms, specifically, propylene, 1-butene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1- Hexene, 3-methyl-1-pentene, 4-methyl-1-pentene,
3,3-dimethyl-1-butene, 1-heptene, methyl-1-hexene, dimethyl-1-pentene, trimethyl-1-butene,
Ethyl-1-pentene, 1-octene, methyl-1-pentene, dimethyl-1-hexene, trimethyl-1-pentene,
Ethyl-1-hexene, methylethyl-1-pentene, diethyl-1-butene, propyl-1-pentene, 1-decene, methyl-1-nonene, dimethyl-1-octene, trimethyl-1
-Heptene, ethyl-1-octene, methylethyl-1-heptene, diethyl-1-hexene, 1-dodecene, 1-hexadedecene and the like.

These α-olefins can be used alone or in combination of two or more. Specific examples of the non-conjugated diene include dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylene norbornene, ethylidene norbornene, and vinyl norbornene.

As the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A), ethylene / propylene / non-conjugated diene copolymer rubber and ethylene / 1-butene / non-conjugated diene copolymer rubber are preferable. In particular, an ethylene / propylene / non-conjugated diene copolymer rubber, particularly an ethylene / propylene / ethylidene norbornene copolymer rubber, is particularly preferred in that a thermoplastic elastomer having an appropriate crosslinked structure can be obtained.

The ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) used in the present invention (when the ethylene / α-olefin / non-conjugated polyene copolymer (A) is oil-extended, The ethylene / α-olefin / non-conjugated polyene copolymer rubber before oil extension) preferably has a Mooney viscosity [ML _{1 + 4} (100 ° C.)] in the range of 100 to 160.

The ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) has an iodine value of 10 to 10.
It is preferably 30 and particularly preferably in the range of 20 to 30. When the iodine value of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) is in the above range, the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) is cross-linked in a well-balanced manner. Thus, an olefinic thermoplastic elastomer having excellent rubber elasticity can be obtained.

The ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) used in the present invention may be a so-called oil-extended product containing a softening agent. By using an oil-extended product, an olefin-based thermoplastic elastomer having excellent flexibility can be obtained. As the softening agent used for this oil-extended product, a softening agent used for ordinary rubber can be used.

Specifically, petroleum-based substances such as process oil, lubricating oil, paraffin, liquid paraffin, petroleum asphalt and petrolatum; coal tars such as coal tar and coal tar pitch; castor oil, linseed oil, rapeseed oil,
Fatty oils such as soybean oil and coconut oil; waxes such as tall oil, beeswax, carnauba wax, and lanolin; fatty acids or metal salts thereof such as ricinoleic acid, palmitic acid, stearic acid, barium stearate, and calcium stearate; Synthetic polymer substances such as coumarone indene resin and atactic polypropylene; ester plasticizers such as dioctyl phthalate, dioctyl adipate and dioctyl sebacate; other microcrystalline waxes, sub (factice), liquid polybutadiene, modified liquid polybutadiene, liquid thiocol And the like.
Of these softeners, paraffinic process oils are particularly preferred.

In the present invention, the softener is ethylene.
α-olefin / non-conjugated polyene copolymer rubber (A) 1
150 parts by weight or less, preferably 2 parts by weight, per 100 parts by weight
To 100 parts by weight, more preferably 5 to 80 parts by weight.

The ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) which may be oil-extended as described above is composed of an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and an olefin It is used in an amount of 40 to 85 parts by weight, preferably 60 to 80 parts by weight, based on 100 parts by weight in total with the system resin (B). However, when the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) is oil-extended, the blending amount of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) is as follows. This is the amount excluding the oil-extended softener.

In the present invention, in addition to the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A), an ethylene / α-olefin / non-conjugated polyene copolymer may be used as long as the object of the present invention is not impaired. A rubber other than the rubber (A) and an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) can be used in combination. Examples of the rubber other than the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) include, for example, styrene / butadiene rubber and its hydrogenated product, styrene / isoprene rubber and its hydrogenated product, nitrile rubber, butyl rubber , Natural rubber, silicone rubber and the like.

Olefin resin (B) The olefin resin (B) used in the present invention is a high molecular weight solid obtained by polymerizing one or more monoolefins by either a high-pressure method or a low-pressure method. Consists of a product. Such resins include, for example, isotactic and syndiotactic monoolefin polymer resins. These representative resins are commercially available.

Examples of suitable raw olefins for the olefin resin (B) include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene,
Examples thereof include 1-decene, 2-methyl-1-propene, 3-methyl-1-pentene, 4-methyl-1-pentene, and 5-methyl-1-hexene. These olefins are used alone or in combination of two or more.

Regarding the above-mentioned polymerization mode, any polymerization mode may be employed, as long as a resinous material can be obtained, whether it is a random type or a block type. These olefinic resins (B) may be used alone or in combination of two or more.

Among these olefin resins (B), propylene polymers, specifically, propylene homopolymer, propylene / ethylene block copolymer,
A propylene / ethylene random copolymer or a propylene / ethylene / butene random copolymer is particularly preferred.

The olefin resin (B) used in the present invention has a melt flow rate (MFR; ASTM D 1238-).
65T, 230 ° C, 2.16kg load) is usually 0.01-100g /
It is preferably 10 minutes, and particularly preferably in the range of 0.05 to 50 g / 10 minutes.

The olefin resin (B) has a role of improving the fluidity and heat resistance of the olefin thermoplastic elastomer. In the present invention, the olefin resin (B) comprises an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and an olefin resin (B).
15 to 60 parts by weight with respect to 100 parts by weight of the total amount of
It is preferably used in a proportion of 20 to 40 parts by weight.

When the olefin-based resin (B) is used in the above ratio, a olefin-based thermoplastic elastomer having excellent flexibility and rubber elasticity and high heat resistance excellent in molding can be obtained.

Other Components The olefin-based thermoplastic elastomer according to the present invention includes:
In addition to the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and the olefin-based resin (B), a softening agent and / or an inorganic filler may be blended as long as the object of the present invention is not impaired. it can.

As described above, the softener is ethylene.α
-The olefin / non-conjugated polyene copolymer rubber (A) may be oil-extended or may be added later without oil-extension. When the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) is added later without oil-extending, the same softener as described above can be used.

When the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) is added later without being oil-extended, the amount of the softening agent is determined by adding 1 to 100 parts by weight of the total amount of the non-conjugated polyene copolymer rubber (A) and the olefin resin (B)
It is used in a proportion of not more than 00 parts by weight, preferably 3 to 80 parts by weight, more preferably 5 to 50 parts by weight. When the softening agent is used in the above ratio, the obtained olefin-based thermoplastic elastomer has excellent fluidity at the time of molding, and does not lower the mechanical properties of the molded article. In the present invention, when the amount of the softener exceeds 100 parts by weight, the heat resistance of the obtained olefin-based thermoplastic elastomer composition tends to decrease.

As the inorganic filler used as required in the present invention, specifically, calcium carbonate, calcium silicate, clay, kaolin, talc, silica, diatomaceous earth, mica powder, asbestos, alumina, Examples include barium sulfate, aluminum sulfate, calcium sulfate, basic magnesium carbonate, molybdenum disulfide, graphite, glass fiber, glass sphere, shirasu balloon, basic magnesium sulfate whisker, calcium titanate whisker, and aluminum borate whisker.

The inorganic filler is used in an amount of 100 parts by weight or less, preferably 2 to 100 parts by weight, based on 100 parts by weight of the total of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and the olefin resin (B). Used in a proportion of 50 parts by weight.
In the present invention, if the amount of the inorganic filler exceeds 100 parts by weight, the rubber elasticity and moldability of the obtained olefin-based thermoplastic elastomer tend to decrease.

Further, in the present invention, a conventionally known heat-resistant stabilizer, an anti-aging agent, a weather-resistant stabilizer, an antistatic agent, a metal soap, a lubricant such as wax, etc. are added to the olefin-based thermoplastic elastomer. It can be added in a range that does not impair the purpose.

Preparation of olefin-based thermoplastic elastomer The olefin-based thermoplastic elastomer according to the present invention comprises the above-mentioned ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and olefin-based resin (B). After mixing with a softening agent and / or an inorganic filler compounded in accordance with the formula (1), and then dynamically performing heat treatment in the presence of a crosslinking agent.

Here, "dynamically heat-treating" means kneading in a molten state. In the present invention, prior to the dynamic heat treatment performed in the presence of the necessary raw material components in the presence of a crosslinking agent,
It is preferable that the whole amount of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and a part or the whole amount of the olefin resin (B) are previously blended in a molten state to form a pellet.

As described above, using a pellet in which the whole amount of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and a part or the whole amount of the olefin resin (B) are blended in a molten state, a crosslinking agent is used. , The total amount of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and the olefin resin (B) are highly dispersed, and the mechanical strength and elongation are excellent. An olefin-based thermoplastic elastomer capable of providing a molded article having excellent rubber elasticity is obtained.

The crosslinking agent used in the present invention includes organic peroxides, phenolic resins, sulfur, hydrosilicone compounds, amino resins, quinones or derivatives thereof, amine compounds, azo compounds, epoxy compounds, isocyanates and the like. Crosslinking agents commonly used in thermosetting rubbers can be mentioned. Among these crosslinking agents, organic peroxides are particularly preferred.

As the organic peroxide used in the present invention, specifically, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane , 2,5-dimethyl-2,5-di- (tert-
Butylperoxy) hexyne-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.

Among them, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane and 2,5-dimethyl-2,5-di-, in terms of odor and scorch stability. (Tert-butylperoxy) hexyne-3,1,3-bis (tert-butylperoxyisopropyl) benzene is preferred, and
5-Dimethyl-2,5-di- (tert-butylperoxy) hexane is most preferred.

The organic peroxide is used in an amount of 0.02 to 3 parts by weight, preferably 0.05 to 1 part by weight, based on 100 parts by weight of the whole object to be treated. If the compounding amount of the organic peroxide is less than the above range, the obtained olefin-based thermoplastic elastomer has a low degree of crosslinking, and thus the molded article has insufficient heat resistance, tensile properties, and rubber elasticity. If the amount is more than the above range, the obtained olefin-based thermoplastic elastomer may have an excessively high degree of cross-linking, resulting in a decrease in moldability.

In the present invention, sulfur, p-quinonedioxime, p, p'-
Peroxy crosslinking aids such as dibenzoylquinone dioxime, N-methyl-N-4-dinitrosoaniline, nitrosobenzene, diphenylguanidine, trimethylolpropane-N, N'-m-phenylenedimaleimide, or divinylbenzene , Triallyl cyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate,
Polyfunctional methacrylate monomers such as trimethylolpropane trimethacrylate and allyl methacrylate, and polyfunctional vinyl monomers such as vinyl butyrate and vinyl stearate can be blended.

By using a compound as described above,
A uniform and mild crosslinking reaction can be expected. Particularly, in the present invention, divinylbenzene is most preferred. Divinylbenzene is easy to handle and has good compatibility with the olefin-based resin (B) and the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A), which are the main components of the above-mentioned crosslinked product, In addition, it has a function of solubilizing the organic peroxide and acts as a dispersant for the organic peroxide, so that a crosslinking effect by heat treatment is uniform, and a thermoplastic elastomer having a good balance between fluidity and physical properties can be obtained. .

Compounds such as the above-mentioned cross-linking aids or polyfunctional vinyl monomers are used in the above-mentioned process.
5 parts by weight or less, preferably 0.3 part by weight,
It is used in such an amount that it becomes ３3 parts by weight.

In order to accelerate the decomposition of the organic peroxide, tertiary amines such as triethylamine, tributylamine, 2,4,6-tri (dimethylamino) phenol, aluminum, cobalt, vanadium, copper, calcium , Zirconium, manganese, magnesium, lead, mercury and other naphthenates and other decomposition accelerators may be used.

The dynamic heat treatment in the present invention is preferably performed in a non-open type apparatus, and is preferably performed in an atmosphere of an inert gas such as nitrogen or carbon dioxide. The temperature of the heat treatment is 300 degrees from the melting point of the olefin resin (B).
° C, usually 150 to 270 ° C, preferably 1 to
70 ° C to 250 ° C. The kneading time is usually 1 to 20 minutes, preferably 1 to 10 minutes. Further, the shear force applied is, 10～50,000Sec ^-1 shear rate, preferably in the range of 100~20,000sec ^-1.

As a kneading apparatus, a mixing roll, an intensive mixer (for example, Banbury mixer, kneader), a single-screw or twin-screw extruder can be used, and a non-open type apparatus is preferable. Particularly preferred.

According to the present invention, by the dynamic heat treatment described above, an olefin-based thermoplastic resin containing an ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and an olefin-based resin (B) An elastomer (composition) is obtained.

The olefin-based thermoplastic elastomer obtained by the above method has a gel content of 8 measured by the following method.
0% or more, preferably 90% or more. [Measurement method of gel content] A sample of an olefin-based thermoplastic elastomer was
00 mg was collected, and 0.5 mm × 0.5 mm × 0.
A sample cut into 5 mm strips is 30 m in a closed container.
After immersing in 1 l of cyclohexane at 23 ° C. for 48 hours,
The sample is taken out on a filter paper and dried at room temperature for 72 hours or more to constant weight.

From the weight of the dried residue, the weight of all cyclohexane-insoluble components (fibrous filler, filler, pigment, etc.) other than the polymer component and the weight of the olefin resin (B) in the sample before immersion in cyclohexane were subtracted. The resulting value is referred to as “corrected final weight (Y)”.

On the other hand, the weight of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) in the sample is referred to as “corrected initial weight (X)”. Where the gel content is
It is obtained by the following equation.

Gel content [% by weight] = [corrected final weight (Y) / corrected initial weight (X)] × 100 A molded article formed from such an olefin-based thermoplastic elastomer is obtained by the JIS K6251 method. Is 3.0 MPa or more, usually 3.0 to 25 M
Pa, preferably 3.5 to 20 MPa, more preferably 4.0 to 15 MPa, and an elongation at break measured based on the JIS K6251 method of 250% or more, usually 250% or more.
-1000%, preferably 270-800%, more preferably 300-700%, and the compression set at -30 ° C for 24 hours measured under JIS K6262 method is 65% or less, usually 65-10%. %, Preferably 60 to 20%, more preferably 55 to 30%.

The olefin-based thermoplastic elastomer according to the present invention can provide a molded article excellent in rubber elasticity, particularly at low temperatures. Automotive seal parts The automotive seal parts according to the present invention are composed of the olefin-based thermoplastic elastomer obtained as described above,
The olefin-based thermoplastic elastomer is obtained by molding into a shape for a seal member by, for example, extrusion molding or injection molding.

The molding method depends on the shape, size and required physical properties of the final product, and is not particularly limited. Further, on the surface of the automotive seal component obtained by the present invention, polyurethane, nylon, an olefin-based resin, a thermoplastic elastomer, or the like may be laminated for improving scratch resistance or lubricity, and design. . The lamination method is not particularly limited, such as lamination using an adhesive.
Here, when manufacturing a laminate comprising a main body and a skin part, the olefin-based thermoplastic elastomer according to the present invention is used as a body-forming material, and an olefin-based resin or an olefin-based thermoplastic elastomer is used as a material for forming the skin part. When is selected, it is possible to extrude the main body and the skin part at the same time with a multilayer extrusion molding machine and heat-seal them,
A laminate can be easily obtained in one simple step.

The olefin resin used as the material for forming the skin part may be the olefin resin (B) or an olefin resin other than the olefin resin (B). Further, the olefin-based thermoplastic elastomer used as the material for forming the skin part may be an olefin-based thermoplastic elastomer other than the olefin-based thermoplastic elastomer according to the present invention, or the present invention used for forming the main body. The olefin-based thermoplastic elastomer according to the present invention, which has a different property from the olefin-based thermoplastic elastomer, may be used.

[0062]

The olefin-based thermoplastic elastomer according to the present invention is excellent in rubber elasticity, particularly rubber elasticity at low temperatures, and can provide a sealing part for automobiles having excellent sealing properties, especially low-temperature sealing properties. .

Since the automotive seal component according to the present invention is made of the olefin-based thermoplastic elastomer according to the present invention, it has excellent sealing properties, especially low-temperature sealing properties. As a seal component for a vehicle, for example, a glass run channel, a weather strip, a window molding, a roof molding, various boots, a draining molding, and the like can be used. Among them, it is particularly suitable for a glass run channel.

[0064]

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

The raw materials used for preparing the olefin-based thermoplastic elastomers of the examples and comparative examples are as follows. (A-1) an oil-extended ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber; the molar ratio of units derived from ethylene to units derived from propylene (ethylene / propylene) is 63/37; 5-ethylidene-2-
100 parts by weight of an ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber having an iodine value of 24 based on norbornene (ENB) and a Mooney viscosity [ML _{1 + 4} (MLC ₊ 100 (100 ° C.)) of 140] are mixed with paraffin-based rubber. Process oil [PW-380 (trade name) manufactured by Idemitsu Kosan Co., Ltd.]
EPDM with oil by weight. (A-2) an oil-extended ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber; a molar ratio of units derived from ethylene to units derived from propylene (ethylene / propylene) is 77/23; 5-ethylidene-2-
100 parts by weight of an ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber having an iodine value of 24 based on norbornene (ENB) and a Mooney viscosity of 140 [ML _{1 + 4} (100 ° C.)] are subjected to a paraffin-based process. EPDM with 60 parts by weight of oil [PW-380 (trade name) manufactured by Idemitsu Kosan Co., Ltd.]. (B-1) Propylene homopolymer; MFR (ASTM D 1
(238, 230 ° C, 2.16 kg load) = 5 g / 10 min (B-2) propylene / ethylene block copolymer;
MFR (ASTM D 1238, 230 ° C, 2.16kg load) = 3g / 1
0 minutes Ethylene content = 8 mol% Propylene content = 92 mol%

[0066]

Example 1 112 parts by weight of oil-extended ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber (A-1) pellets (70 parts by weight of rubber polymer, 42 parts by weight of softener); 30 parts by weight of the propylene homopolymer (B-1) pellets were fed to a twin-screw extruder set at 220 ° C and kneaded at a maximum shear rate of 2000 (1 / sec) to obtain a master batch pellet (1).

Next, 100 parts by weight of the obtained masterbatch pellet (1) was added to an organic peroxide [2,5-dimethyl-
2,5-di- (tert-butylperoxy) hexane] 0.
After thoroughly mixing 8 parts by weight and 1.4 parts by weight of divinylbenzene (DVB) in a Henschel mixer, the mixture is fed to a twin-screw extruder and subjected to dynamic heat treatment under the following conditions to obtain an olefin-based thermoplastic elastomer. A pellet was obtained. <Dynamic heat treatment conditions> Extruder: ZSK-53 manufactured by Werner & Freidel
(Part number), Screw diameter 53mm Temperature setting: C1 / C2 / C3 / C4 / C5 / D = 140
/ 160/180/220/220/200 (° C.) Maximum shear rate: 2800 (1 / second) Extrusion amount: 50 (kg / h) Then, a test piece for a predetermined compression set is obtained by injection molding using the pellets. JIS K6
-30 ° C, 23 ° C and 7
The residual strain after compression deformation at 0 ° C. for 24 hours was measured. Also, JIS-3 dumbbells were punched out of a 2 mm thick sheet press-formed at 200 ° C., and JIS K62
A tensile test was performed based on Method 51 to measure tensile strength and elongation at break. Table 1 shows the results.

Further, this thermoplastic elastomer is
1 and 2 to form a glass run channel main body 2 and a draining part 3 as shown in FIGS. 1 and 2. The intrinsic viscosity [η] measured in a decalin solvent at 135 ° C. is 28 dl. / G ultra high molecular weight polyethylene 23% and low molecular weight polyethylene 77 having an intrinsic viscosity [η] of 0.73 dl / g measured in a decalin solvent at 135 ° C.
% By weight of a polyethylene composition (intrinsic viscosity [η] of 7.0 dl / g measured in a decalin solvent at 135 ° C.) was laminated and extruded to obtain a glass run channel 1.

The obtained glass run channel 1 has a substantially trapezoidal shape. In FIG. 3, the total length of the inclined portion and the horizontal portion of the glass run channel 1 fixed to the window frame 13 is 1500 mm. The length of the vertical portion is 900 mm, the outer width at the bottom of the main body 2 is 15 mm, the outer width at the side is 20 mm, and the length of the drainer 3 is 10 mm in FIG. Equally, the average thickness of the ultrahigh molecular weight polyethylene composition layer was 30 μm.

The obtained glass run channel 1 will be described in detail.
In FIG. 1 showing its cross-sectional structure, a main body 2 having a groove-like (U-shape) cross-section in a cross section and a tongue-shaped drain portion 3 protruding from the vicinity of the top of the side wall toward the center. ing. The pair of drainers 3 and 3 extend inclining toward the inside of the groove of the main body 2, and the outer surface side is a window glass contact part 4, and the tips 5 and 5 can be opened and closed with each other. Is in a good positional relationship. The main body 2 is provided with a hook 6 for attachment to a window frame on an outer wall thereof.

The main body 2 and the draining part 3 are integrally formed of an elastomer. The window glass contact part 4 is composed of a base layer made of a thermoplastic elastomer and a slip resin layer made of an ultrahigh molecular weight polyolefin composition. Constitute. As shown in FIG. 2 showing the window glass contact portion 4 in an enlarged manner, the surface 8 of the base layer 7 made of a thermoplastic elastomer has a repeating pattern of fine irregularities. A lubricating resin layer 9 made of an ultrahigh molecular weight polyolefin composition is laminated on the surface 8 having such a sharkskin-like fine uneven pattern by heat fusion, and the outer surface 10 has the same fine unevenness. The pattern is repeated. 3 and 4 for explaining attachment of the glass run channel 1 to an automobile.
In FIG. 5 and FIG. 5, a window glass 12 is provided on a door 11 of the automobile so as to be opened and closed by a vertical movement, while a glass run channel 1 is fixed to a window frame 13. That is, in FIG. 4 and FIG.
The cross section is formed in a U-shape as a whole, and an inward projection 15 is formed at the entrance of the concave portion 14. The glass run channel 1 is fixed to the window frame 13 by inserting the glass run channel 1 into the concave portion 14 and engaging the engaging hook 6 with the projection 15. As shown in FIG. 4, when the window glass 12 is lowered, the tips 5, 5 of the glass sliding parts face each other and are closed, and as shown in FIG. In the figure, the tips 5, 5 of the window glass sliding portions are separated by the window glass 12 inserted between them, but are in contact with the window glass surface.

The glass run channel 1 obtained as described above was mounted on a test window frame, and a window glass having a thickness of 3.2 mm was mounted thereon, and a durability test was performed 50,000 times repeatedly.

The sealability was evaluated by measuring the distance between the two lip portions (tips 5 and 5 of the glass sliding portion) before and after the durability test. When the distance between the lips after the endurance test is larger than that before the endurance test, it indicates that the sealing property has decreased.

The results are shown in Table 1.

[0075]

Example 2 128 parts by weight of oil-extended ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber (A-1) pellets (80 parts by weight of rubber polymer, 48 parts by weight of softener); 20 parts by weight of a propylene / ethylene block copolymer (B-2) pellet were kneaded in the same manner as in Example 1 to obtain a master batch pellet (2).

Next, 90 parts by weight of the obtained master batch pellets (2), 10 parts by weight of propylene / ethylene block copolymer (B-2) pellets, and an organic peroxide [2,5-dimethyl-2,5 -Di- (tert-butylperoxy) hexane] and 1.0 part by weight of divinylbenzene (D
1.8 parts by weight of VB) were sufficiently mixed in a Henschel mixer, and then fed to a twin-screw extruder to perform dynamic heat treatment in the same manner as in Example 1 to obtain pellets of an olefin-based thermoplastic elastomer.

Next, the compression set, tensile strength and elongation at break were measured in the same manner as in Example 1 using the pellets. Further, a glass run channel main body and a drain portion were formed from the thermoplastic elastomer pellets in the same manner as in Example 1, and a durability test was performed to evaluate the sealability.

Table 1 shows the results.

[0079]

Comparative Example 1 112 parts by weight of oil-extended ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber (A-2) pellets (70 parts by weight of rubber polymer, 42 parts by weight of softener); 30 parts by weight of propylene / ethylene block copolymer (B-1) pellets were kneaded in the same manner as in Example 1 to obtain a master batch pellet (3).

Next, 100 parts by weight of the obtained masterbatch pellet (3) was added to an organic peroxide [2,5-dimethyl-
2,5-di- (tert-butylperoxy) hexane] 0.
After thoroughly mixing 8 parts by weight and 1.4 parts by weight of divinylbenzene (DVB) in a Henschel mixer, the mixture is fed to a twin-screw extruder, subjected to a dynamic heat treatment in the same manner as in Example 1, and subjected to olefin heat treatment. A pellet of a plastic elastomer was obtained.

Next, compression set, tensile strength and elongation at break were measured using the pellets in the same manner as in Example 1. Further, a glass run channel main body and a drain portion were formed from the thermoplastic elastomer pellets in the same manner as in Example 1, and a durability test was performed to evaluate the sealability.

The results are shown in Table 1.

[0083]

Comparative Example 2 128 parts by weight of an oil-extended ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber (A-2) pellet (80 parts by weight of a rubber polymer and 48 parts by weight of a softener); 20 parts by weight of the propylene / ethylene block copolymer (B-2) pellets were kneaded in the same manner as in Example 1 to obtain a master batch pellet (2).

Next, 90 parts by weight of the obtained master batch pellets (2), 10 parts by weight of propylene / ethylene block copolymer (B-2) pellets, and an organic peroxide [2,5-dimethyl-2,5 -Di- (tert-butylperoxy) hexane] and 1.0 part by weight of divinylbenzene (D
1.8 parts by weight of VB) were sufficiently mixed in a Henschel mixer, and then fed to a twin-screw extruder to perform dynamic heat treatment in the same manner as in Example 1 to obtain pellets of an olefin-based thermoplastic elastomer.

Next, compression set, tensile strength and elongation at break were measured in the same manner as in Example 1 using the pellets. Further, a glass run channel main body and a drain portion were formed from the thermoplastic elastomer pellets in the same manner as in Example 1, and a durability test was performed to evaluate the sealability.

The results are shown in Table 1.

[0087]

Example 3 112 parts by weight of oil-extended ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber (A-1) pellets (70 parts by weight of rubber polymer, 42 parts by weight of softener); Organic peroxide [2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane] without melt-kneading 30 parts by weight of propylene homopolymer (B-1) pellets in advance. After thoroughly mixing with 14 parts by weight and 1.99 parts by weight of divinylbenzene (DVB) in a Henschel mixer, the mixture is fed to a twin-screw extruder, subjected to a dynamic heat treatment in the same manner as in Example 1, and subjected to olefin-based thermoplastics. An elastomer pellet was obtained. The raw materials and the compounding ratio are the same as in Example 1.

Next, the compression set, tensile strength and elongation at break were measured in the same manner as in Example 1 using the pellets. Further, a glass run channel main body and a drain portion were formed from the thermoplastic elastomer pellets in the same manner as in Example 1, and a durability test was performed to evaluate the sealability.

The results are shown in Table 1.

[0090]

Example 4 77.8 parts by weight of oil-extended ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber (A-1) pellets (48.7 parts by weight of rubber polymer,
(29.2 parts by weight of a softening agent) and 22.2 parts by weight of propylene / ethylene block copolymer (B-2) pellets without prior melt-kneading, an organic peroxide [2,5-dimethyl-2,5 -Di- (tert-butylperoxy) hexane]
1.0 part by weight, and divinylbenzene (DVB) 1.
After sufficiently mixing with 8 parts by weight in a Henschel mixer, the mixture was fed to a twin-screw extruder and subjected to dynamic heat treatment in the same manner as in Example 1 to obtain pellets of an olefin-based thermoplastic elastomer. The raw materials and the compounding ratio are the same as in Example 2.

Next, compression set, tensile strength and elongation at break were measured using the pellets in the same manner as in Example 1. Further, a glass run channel main body and a drain portion were formed from the thermoplastic elastomer pellets in the same manner as in Example 1, and a durability test was performed to evaluate the sealability.

Table 1 shows the results.

[0093]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a sectional view of a glass run channel obtained in an example and a comparative example.

FIG. 2 is an enlarged sectional view of a contact portion of the glass run channel shown in FIG. 1 with a window glass.

FIG. 3 is a diagram illustrating attachment of a glass run channel to an automobile door.

FIG. 4 is a sectional view showing a state of a glass run channel when a window glass is opened.

FIG. 5 is a cross-sectional view showing a state of the glass run channel when the window glass is closed.

[Explanation of symbols]

1 ····· Glass run channel 2 ····· Glass run channel body 3 ····· Draining part 4 ····· Contact part with window glass 7 ····· Made of thermoplastic elastomer Base layer 8 ····· Substrate layer surface having repeating pattern of fine irregularities 9 ····· Slip resin layer made of ultrahigh molecular weight polyolefin composition 10 ··· Slip resin having repeating pattern of fine irregularities Layer surface

Continuation of the front page (72) Inventor Akira Uchiyama 3 Chigusa Beach, Ichihara City, Chiba Prefecture Mitsui Chemicals Co., Ltd. F-term (reference) 3D127 AA11 AA15 BB01 CB05 CC05 CC13 DE01 DE09 DE17 EE15 EE16 EE25 4F070 AA13 AA15 AA16 AC56 AE08 FB03 FB06 FC05 GA05 GC07 4F071 AA15 AA15X AA20 AA20X AA21 AA76 AC08 AH07 BB06 4J002 AE05W BB03X BB12X BB15W BB17X FD146 GN00

Claims (6)

[Claims] An olefin-based thermoplastic elastomer having a gel content of 80% or more, and a molded product obtained by molding the olefin-based thermoplastic elastomer has a tensile strength (JIS K-6251) of 3.0 MPa. The elongation at break (JIS K-6251) is 250% or more, and -30 based on JIS K6262 method.
A thermoplastic elastomer having a compression set of 65% or less measured at 24 ° C. for 24 hours. 2. The olefin-based thermoplastic elastomer comprises: (A) ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated polyene, and a molar ratio of ethylene to α-olefin (ethylene / α -Olefin) 55 /
45-70 / 30 ethylene / α-olefin / non-conjugated polyene copolymer rubber 40 which may be oil-extended
And (B) 15 to 60 parts by weight of the olefin resin [component (A)
The total amount of the component (B) and the component (B) is 100 parts by weight, and when the component (A) is oil-extended, the 40 to 85 parts by weight is the amount of the ethylene / α-olefin / non-conjugated polyene before oil extension. Shows the compounding amount of the copolymer rubber. And a mixture comprising
The olefin-based thermoplastic elastomer according to claim 1, which is a thermoplastic elastomer composition obtained by dynamically heat-treating in the presence of a crosslinking agent. 3. The ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) (when the ethylene / α-olefin / non-conjugated polyene copolymer (A) is oil-extended, the oil Mooney viscosity of the ethylene / α-olefin / non-conjugated polyene copolymer rubber before expansion [ML _{1 + 4} (10
0 ° C.) is in the range of 100 to 160. 3. The olefin-based thermoplastic elastomer according to claim 2, wherein 4. A pellet prepared by previously blending the whole amount of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and the whole amount of the olefin resin (B) in a molten state, and a crosslinking agent. The olefinic thermoplastic elastomer according to claim 2, wherein the olefinic thermoplastic elastomer is obtained by throwing into a twin-screw extruder and dynamically performing heat treatment. 5. A pellet, which is prepared by previously blending the whole amount of the ethylene / α-olefin / non-conjugated polyene copolymer rubber (A) and a part of the olefin resin (B) in a molten state. The olefin-based thermoplastic elastomer according to claim 2, which is obtained by charging the remaining pellets of the resin (B) and the cross-linking agent into a twin-screw extruder and dynamically performing heat treatment. 6. An automotive seal component comprising the olefin-based thermoplastic elastomer according to claim 1.