Thermoplastic elastomer composition and automotive weatherstrip

Abstract

To provide a thermoplastic elastomer composition exhibiting superior flowability over a broad temperature range and achieving reduced odor when molded.SOLUTION: A thermoplastic elastomer composition according to the present invention is a composition produced through melt-kneading of an ethylene-α-olefin-non-conjugated polyene copolymer rubber (A), which is a copolymer of ethylene, a C3-20 α-olefin, and a non-conjugated polyene, a polyolefin resin (B), and a mineral oil-based softener (C), in the presence of a crosslinker (D). The thermoplastic elastomer composition contains a deodorant (F).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a thermoplastic elastomer composition and an automotive weatherstrip.

Background Art

[0002] There is known an olefin-based thermoplastic elastomer obtained by dynamically heat-treating a composition composed of an ethylene-based copolymer and a polyolefin resin in the presence of an organic peroxide (see, for example, Patent Document 1). Molding using such an olefin-based thermoplastic elastomer as a material has the advantage that a vulcanization step is unnecessary during its production, and ordinary thermoplastic resin molding methods such as injection molding, profile extrusion molding, calendering, blow molding, etc. can be employed, and it can be applied to complex shapes.

[0003] On the other hand, since such an olefin-based thermoplastic elastomer needs to be heated to a molten state and molded while flowing into a mold having a specific shape, unreacted raw materials and the thermoplastic elastomer itself decompose to generate low molecular components, which cause odors.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Some aspects of the present invention provide a thermoplastic elastomer composition that is excellent in fluidity in a wide temperature range and has suppressed odor when molded.

Means for Solving the Problems

[0006] The present invention has been made to solve at least a part of the above-described problems and can be realized in the following aspects.

[0007] One aspect of the thermoplastic elastomer composition according to the present invention is a composition obtained by melt-kneading an ethylene·α-olefin·non-conjugated polyene copolymer rubber (A) which is a copolymer of ethylene, an α-olefin having 3 to 20 carbon atoms, and a non-conjugated polyene, a polyolefin resin (B), and a mineral oil-based softening agent (C) in the presence of a crosslinking agent (D), and is a thermoplastic elastomer composition containing a deodorant (F).

[0008] In one aspect of the thermoplastic elastomer composition, when the thermoplastic elastomer is subjected to differential scanning calorimetry with a temperature decrease rate of -10 °C / min from 200 °C to -80 °C in accordance with ISO11357-3:2018, the observed exothermic peak temperature can be 70 to 85 °C.

[0009] In any aspect of the thermoplastic elastomer composition, the component (F) can be at least one selected from the group consisting of silica, metal oxide particles, metal hydroxides, activated carbon, amine compounds, and phosphorus compounds.

[0010] In any aspect of the thermoplastic elastomer composition, when the total of the component (A), the component (B), and the component (C) is 100 parts by mass, the content ratio of the component (F) can be 0.1 to 20 parts by mass.

[0011] In any aspect of the thermoplastic elastomer composition, When the total of the component (A), the component (B), and the component (C) is 100 parts by mass, the content ratio of the component (A) is 10 to 50 parts by mass, the content ratio of the component (B) is 1 to 15 parts by mass, the content ratio of the component (C) is 4 to 50 parts by mass, the content ratio of the component (D) is 10 to 50 parts by mass, and the content ratio of the component (F) can be 0.1 to 20 parts by mass.

[0012] One aspect according to the present invention can be a weatherstrip for automobiles that uses at least a part of the thermoplastic elastomer composition.

Effects of the Invention

[0013] According to the thermoplastic elastomer composition of the present invention, since it has excellent fluidity in a wide temperature range, it is easy to mold into a preferable shape, and a molded product with a good appearance can be obtained.

Modes for Carrying Out the Invention

[0014] Hereinafter, preferred embodiments according to the present invention will be described in detail. It should be understood that the present invention is not limited only to the embodiments described below, and includes various modified examples implemented within the scope of not changing the gist of the present invention.

[0015] In this specification, a numerical range described using "X to Y" is interpreted as including the numerical value X as the lower limit value and including the numerical value Y as the upper limit value.

[0016] In this specification, ethylene·α-olefin·non-conjugated polyene copolymer rubber (A) may be abbreviated as "component (A)", polyolefin resin (B) as "component (B)", mineral oil-based softening agent (C) as "component (C)", crosslinking agent (D) as "component (D)", crosslinking assistant (E) as "component (E)", deodorant (F) as "component (F)", and differential scanning calorimetry as "DSC measurement", respectively.

[0017] 1. Thermoplastic Elastomer Composition The thermoplastic elastomer composition according to an embodiment of the present invention is a composition obtained by blending a deodorant (F) into a kneaded product obtained by melt-kneading an ethylene·α-olefin·non-conjugated polyene copolymer rubber (A) which is a copolymer of ethylene, an α-olefin having 3 to 20 carbon atoms and a non-conjugated polyene, a polyolefin resin (B), and a mineral oil-based softening agent (C) in the presence of a crosslinking agent (D) and a crosslinking aid (E).

[0018] Hereinafter, each component contained in the thermoplastic elastomer composition according to the present embodiment will be described.

[0019] 1.1. Ethylene·α-olefin·non-conjugated polyene copolymer rubber (A) Examples of the ethylene·α-olefin·non-conjugated polyene copolymer rubber (A) used in the present embodiment include random copolymers mainly composed of ethylene and an α-olefin having 3 to 10 carbon atoms, such as ethylene·propylene·non-conjugated diene terpolymer rubber and ethylene·1-butene·non-conjugated diene terpolymer rubber.

[0020] Examples of the α-olefin having 3 to 10 carbon atoms include propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3-ethyl-1-pentene, 1-heptene, 1-octene, 1-decene, etc. These can be used alone or in combination of two or more. Among these, propylene and 1-butene are particularly preferable.

[0021] Examples of the non-conjugated diene include 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,7-octadiene, 1,9-decadiene, 3,6-dimethyl-1,7-octadiene, 4,5-dimethyl-1,7-octadiene, 5-methyl-1,8-nonadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, 2,5-norbornadiene, etc. These can be used alone or in combination of two or more. Among these, 1,4-hexadiene, dicyclopentadiene, and 5-ethylidene-2-norbornene are particularly preferred.

[0022] Specific examples of component (A) include ethylene·propylene·dicyclopentadiene terpolymer, ethylene·propylene·5-ethylidene-2-norbornene terpolymer, and ethylene·1-butene·5-ethylidene-2-norbornene terpolymer, etc.

[0023] In these terpolymers, when the total of ethylene units and propylene or 1-butene units is 100 mol%, the ethylene content is preferably 50 - 95 mol%, more preferably 60 - 90 mol%. Also, when the total of ethylene units and propylene or 1-butene units is 100 mol%, the propylene or 1-butene content is preferably 5 - 50 mol%, more preferably 10 - 40 mol%. When the ethylene content of the above terpolymer is within the above range, the crosslinking efficiency tends to improve, so the compression set characteristics may be suppressed low.

[0024] Also, when the total of ethylene units and propylene or 1-butene units is 100 mass%, the dicyclopentadiene or 5-ethylidene-2-norbornene content is preferably 3 - 10 mass%, more preferably 3 - 8 mass%.

[0025] When the intrinsic viscosity [η] of the ethylene·α-olefin·non-conjugated polyene copolymer rubber (A) is measured at 135 °C in a decalin solvent, it is preferably 1 to 10 dl / g, more preferably 2 to 10 dl / g, and particularly preferably 3 to 9 dl / g.

[0026] Also, the dispersion ratio (Mw / Mn) of the ethylene·α-olefin·non-conjugated polyene copolymer rubber (A) is preferably 5.0 or less, more preferably 4.5 or less, and particularly preferably 4.0 or less. Here, Mw represents the weight-average molecular weight, Mn represents the number-average molecular weight, and Mw and Mn are polystyrene conversion values measured by gel permeation chromatography (GPC).

[0027] Component (A) may be compounded as an oil-extended rubber with a mineral oil-based softener (C) added during the manufacturing process. By compounding component (A) as an oil-extended rubber, the moldability tends to be improved.

[0028] When the total amount of component (A), component (B), and component (C) is 100% by mass, the content ratio of component (A) in the thermoplastic elastomer composition according to this embodiment is preferably 17 to 50% by mass, more preferably 20 to 47% by mass, and particularly preferably 22 to 44% by mass.

[0029] 1.2. Polyolefin resin (B) When the polyolefin resin (B) used in this embodiment is subjected to DSC measurement by cooling from 200 °C to -80 °C at -10 °C / min in accordance with ISO 11357-3:2018, and the total heat of the peaks observed is taken as 100%, when the temperature reaches 95% by integrating the observed peaks from the high-temperature side, it is preferably 75 to 95 °C. The observation of an exothermic peak at a low temperature makes it easier to obtain a thermoplastic elastomer composition that does not solidify and has fluidity even at low temperatures. Such a thermoplastic elastomer composition is (1 It is possible to have characteristics such as a wider process window for molding than conventional ones, (2) less likely to cause defects such as poor molding appearance, and (3) being able to be processed even at relatively low temperatures, so an improvement in productivity can be expected.

[0030] Examples of the polyolefin resin include polypropylene, propylene-ethylene copolymer, propylene-1-butene copolymer, propylene-1-pentene copolymer, propylene-3-methyl-1-butene copolymer, propylene-1-hexene copolymer, propylene-3-methyl-1-pentene copolymer, propylene-4-methyl-1-pentene copolymer, propylene-3-ethyl-1-pentene copolymer, propylene-1-octene copolymer, propylene-1-decene copolymer, and propylene-1-undecene copolymer. Among these, polypropylene and propylene-ethylene copolymer are preferably used. These can be used alone or in combination of two or more.

[0031] When the total amount of components (A), (B), and (C) is 100% by mass, the content ratio of the polyolefin resin (B) in the thermoplastic elastomer composition according to the present embodiment is preferably 8 to 50% by mass, more preferably 15 to 40% by mass, and particularly preferably 20 to 35% by mass.

[0032] 1.3. Mineral oil-based softener (C) The mineral oil-based softener used in the present embodiment preferably has a weight average molecular weight of 300 to 2000, particularly 500 to 1500. The rubber softener composed of mineral oil hydrocarbons is generally a mixture of an aromatic ring, a naphthene ring, and a paraffin chain. Those in which the carbon number of the paraffin chain accounts for 50% or more of the total carbon number are paraffin-based oils, those in which the carbon number of the naphthene ring is 30 to 45% of the total carbon number are naphthene-based oils, and those in which the carbon number of the aromatic ring is 30% or more of the total carbon number are aromatic-based oils, and they are classified respectively. In the present invention, paraffin-based ones are preferred, and particularly hydrogenated paraffin-based ones are preferred. Also, the mineral oil hydrocarbon has a kinematic viscosity at 40°C of 2×10-5 ~8×10 -4 m 2 / s (20~800 cSt), particularly 5×10 -5 ~6×10 -4 m 2 / s (50~600 cSt), and those having a pour point of -40~0°C, particularly -30~0°C, are preferred.

[0033] When the component (A) used in this embodiment is an oil-extended rubber, the extender oil contained in the oil-extended rubber is preferably also a mineral oil-based softener.

[0034] The blending ratio of the mineral oil-based softener (C) is such that the mass ratio (C) / (A) of the mineral oil-based softener (C) to the ethylene·α-olefin·non-conjugated polyene copolymer rubber (A) is preferably 0.8~1.9, more preferably 0.9~1.8, and particularly preferably 1~1.7. When the blending ratio of the softener is within the above range, appropriate fluidity is imparted to the thermoplastic elastomer composition, and the occurrence of oil bleed can be suppressed.

[0035] 1.4. Crosslinking agent (D) As the crosslinking agent (D) used in this embodiment, known substances known as crosslinking agents can be used, and preferably, organic peroxides (D1) or phenolic resin-based crosslinking agents (D2) can be used.

[0036] Examples of the organic peroxide (D1) include 1,3-di(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexene-3, 1,3-bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,2-di(tert-butylper -oxy)-p-isopropylbenzene, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl peroxide, tert-butyl cumyl peroxide, di-tert-butyl peroxide, p-menthane peroxide, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, dilauroyl peroxide, diacetyl peroxide, tert-butyl peroxybenzoate, 2,4-dichlorobenzoyl peroxide, p-chlorobenzoyl peroxide, benzoyl peroxide, di(tert-butylperoxy) diperbenzoate, n-butyl-4,4-bis(tert-butylperoxy) valerate, tert-butyl peroxyisopropyl carbonate, and the like. Among these organic peroxides, dialkyl peroxides such as 1,3-bis(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane are preferred.

[0037] The phenolic resin crosslinking agent (D2) is typically a resol resin obtained by condensing an alkyl-substituted or unsubstituted phenol with an aldehyde compound such as formaldehyde in the presence of an alkali catalyst. The alkyl group of the alkyl-substituted phenol is preferably an alkyl group having 1 to 10 carbon atoms, and a part of the hydrogen atoms in the alkyl group may be substituted with a halogen atom. In particular, dimethylol phenols or phenolic resins substituted with an alkyl group having 1 to 10 carbon atoms or a halogenated alkyl group are preferred.

[0038] From the viewpoint of making dynamic crosslinking more likely to occur and making it easier to adjust the heat resistance, tensile properties, etc. of the molded article within a desired range, the content of the crosslinking example is preferably 0.01 part by mass or more and 15 parts by mass or less, more preferably 0.03 part by mass or more and 12 parts by mass or less, when the component (A) is 100 parts by mass.

[0039] 1.5. Crosslinking Aid (E) When an organic peroxide (D1) is used as the crosslinking agent (D) in this embodiment, the crosslinking aid (E) optionally used is preferably a polyfunctional compound. In the present invention, the "polyfunctional compound" is a low molecular weight compound having two or more non-conjugated carbon-carbon double bonds in one molecule, and by using it in combination with other crosslinking agents having no such double bonds, the crosslinking reaction can proceed efficiently, and a uniform crosslinked structure and excellent rubber elasticity can be exhibited.

[0040] Examples of the polyfunctional compound include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, diallyl phthalate, diallyl terephthalate, tetraallyloxyethane, triallyl cyanurate, N,N'-m-phenylenebismaleimide, N,N'-tolylene bismaleimide, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, divinylbenzene, zinc di(meth)acrylate, and the like. These polyfunctional compounds may be used alone or in combination of two or more.

[0041] By using in combination a polyfunctional compound having high reactivity with free radicals generated during melt-kneading, the crosslinking reaction can proceed rapidly to form a rubber domain with a high crosslink density, and side reactions other than the crosslinking reaction of free radicals (for example, disproportionation reaction between free radical species, hydrogen abstraction reaction not involved in the crosslinking reaction, β-elimination reaction involving main chain scission of copolymer rubber or polyolefin resin) can be suppressed.

[0042] From the viewpoint of maintaining the uniformity of the phase structure and the moldability, the blending ratio of the crosslinking aid (E) is preferably 3 parts by mass or less, more preferably 0.1 to 1.5 parts by mass, and particularly preferably 0.2 to 1.2 parts by mass with respect to 100 parts by mass in total of the component (A), the component (B), and the component (C).

[0043] 1.6. Deodorant (F) The deodorant (F) used in this embodiment may be a component that physically adsorbs odor substances or a component that chemically acts on odor substances to suppress volatilization. Examples of such deodorants include activated carbon, silica, alumina, zeolite, quaternary ammonium salts, heterocyclic compounds, metal compounds, acidic compounds, basic compounds, and the like.

[0044] Examples of quaternary ammonium salts include alkylbenzyldimethylammonium salts, didecyldimethylammonium salts, alkyltrimethylammonium salts, and the like. Examples of heterocyclic compounds include cetylpyridinium salts, isothiazolin-based compounds such as methylisothiazolinone and octylisothiazolinone, and the like. Examples of metal compounds include silver oxide, silver-containing water-soluble glass, zeolite supported with silver, silver nanoparticles, silver ions, silver nitrate, silver sulfide, zinc oxide, copper oxide, zinc ions, copper ions, gold nanoparticles, and the like. Examples of acidic compounds include citric acid, malic acid, hydrochloric acid, lactic acid, and the like. Examples of basic compounds include sodium hydroxide, potassium hydroxide, sodium hydrogen carbonate, sodium carbonate, calcium oxide, calcium hydroxide, and the like.

[0045] These deodorants may be used alone or in combination of a plurality of them, such as a deodorant that physically adsorbs odor components and a deodorant that chemically acts.

[0046] The content of the component (F) in the thermoplastic elastomer can be arbitrarily adjusted according to the type of the deodorant component, the type of the odor component, and the like. When the total of the component (A), the component (B), and the component (C) is 100 parts by mass, the content of the component (F) is usually 0.1 to 20 parts by mass, preferably 0.2 to 15 parts by mass, more preferably 0.3 to 10 parts by mass.

[0047] 1.7. Amorphous polyolefin resin (G) The amorphous polyolefin resin (G) optionally used in the present embodiment, when subjected to DSC measurement with a temperature increase rate of 10 °C / min from -80 °C to 200 °C in accordance with ISO 11357-3:2018, the endothermic amount of the peak observed is 1 to 25 J·g -1 It is preferably this. By including such an amorphous polyolefin resin, the composition has a low hardness and while maintaining fluidity at low temperatures, a molded product with good appearance can be obtained.

[0048] Examples of the amorphous polyolefin resin include homopolymers such as atactic polypropylene and atactic poly-1-butene, and copolymers of propylene (containing 50 mol% or more) and other α-olefins (ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, etc.), copolymers of 1-butene (containing 50 mol% or more) and other α-olefins (ethylene, propylene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, etc.), and the like. Among these, atactic polypropylene (propylene content 50 mol% or more), copolymers of propylene (containing 50 mol% or more) and ethylene, and copolymers of propylene and 1-butene are particularly preferred. These can be used alone or in combination of two or more.

[0049] 1.8. Other additives In the thermoplastic elastomer composition according to the present embodiment, various additives, for example, lubricants, anti-aging agents, heat stabilizers, weather resistance agents, metal deactivators, ultraviolet absorbers, light stabilizers, copper damage prevention Stabilizers such as inhibitors, antibacterial and antifungal agents, dispersants, plasticizers, crystal nucleating agents, flame retardants, silicone oil, silicone polymers, tackifiers, foaming aids, colorants such as titanium oxide and carbon black, metal powders such as ferrite, inorganic fibers such as glass fibers and metal fibers, organic fibers such as carbon fibers and aramid fibers, composite fibers, inorganic whiskers such as potassium titanate whiskers, glass beads, glass balloons, glass flakes, asbestos, mica, calcium carbonate, talc, silica, calcium silicate, hydrotalcite, kaolin, diatomaceous earth, graphite, pumice, EVA powder, cotton flock, cork powder, barium sulfate, fluororesin, fillers such as polymer beads or mixtures thereof, fillers such as polyolefin wax, cellulose powder, rubber powder, and wood powder, low molecular weight polymers, etc. can be compounded and used.

[0050] <Softening agents other than mineral oil-based> There is no particular limitation as long as it is a commonly used rubber softening agent. For example, vegetable oils (such as palm oil), esters of fatty acids and higher alcohols (such as phthalic acid diesters), triester phosphates, low molecular weight hydrocarbons such as polybutene-based and polybutadiene-based, etc. can be mentioned.

[0051] 1.9. Molded article and uses The thermoplastic elastomer composition according to this embodiment can be made into a molded article using various molding methods such as injection molding methods such as gas injection molding method, injection compression molding method, and short shot foaming molding method, extrusion molding method, blow molding method, compression molding method, etc. Among these, the injection molding method is preferable. For example, when performing injection molding, the molding temperature is generally 130 to 280°C, preferably 150 to 250°C. Also, the injection pressure is usually 5 to 100 MPa, preferably 10 to 80 MPa. On the other hand, the mold temperature is usually 0 to 80°C, preferably 20 to 60°C. In addition, after performing these moldings, secondary processes such as laminating molding and thermoforming can be further performed on the obtained molded article.

[0052] The thermoplastic elastomer composition according to this embodiment is suitable as a member for automobiles and building materials, particularly as a weatherstrip member for automobiles. Further, the thermoplastic elastomer composition according to this embodiment can be used in a wide range of fields such as automotive parts (airbag storage covers, center panels, center console boxes, door trims, pillars, assist grips, steering wheels, weatherstrips, ceiling materials, interior seats, bumper moldings, side moldings, air spoilers, air duct hoses, cup holders, side brake grips, shift knob covers, flapper door seals, wire harness grommets, rack and pinion boots, suspension cover boots, glass guides, inner belt line seals, roof guides, trunk lid seals, molded dead quarter window gaskets, corner moldings, glass encapsulations, hood seals, glass run channels, secondary seals, body panels, side shields, door skins, hoses, wire harness covers, seat adjuster covers, various packings, etc.), civil engineering and building materials parts (soil improvement sheets, water supply boards, civil engineering materials and building materials such as noise and vibration prevention walls, various gaskets and sheets for civil engineering and construction, waterstop materials, joint materials, window frames, window frame packings, etc.), sanitary products (sanitary products, disposable diapers, toothbrush grips, etc.), sports goods (grips for golf clubs and tennis rackets, etc.), industrial parts (medical containers, gaskets, packings, etc.), food parts (containers, packings, etc.), medical device parts, electric wires, miscellaneous goods, toys, etc.).

[0053] 2. Method for manufacturing thermoplastic elastomer composition The thermoplastic elastomer composition according to this embodiment can also be obtained by melt-kneading an ethylene·α-olefin·non-conjugated polyene copolymer rubber (A), a polyolefin resin (B), a mineral oil-based softening agent (C), and a deodorant (F) in the presence of a crosslinking agent (D) and an optional crosslinking aid (E). Alternatively, the ethylene·α-olefin·non-conjugated polyene copolymer rubber (A), the polyolefin resin (B), and the mineral oil-based softening agent (C) can be mixed with the crosslinking agent (D) and an optional crosslinking aid It is also possible to obtain a composition by further mixing a deodorant (F) with the composition obtained by melt-kneading in the presence of (E). "Melt-kneading" in the present invention refers to performing both applying a shearing force and heating.

[0054] Examples of the apparatus capable of performing melt-kneading include apparatuses such as an open-type mixing roll, a non-open-type Banbury mixer, a kneader, a single-screw extruder, a co-rotating continuous twin-screw extruder, and a counter-rotating continuous twin-screw kneader. Further, the treatment performed with this kneading apparatus may be either batch type or continuous type.

[0055] From the viewpoint of the balance between the melting and cross-linking reaction of components (A) and (B), the temperature condition of melt-kneading is preferably carried out in the range of 150 to 250°C. The treatment time of melt-kneading is not particularly limited, but considering productivity and the like, it is usually 0.1 to 30 minutes.

[0056] 3. Examples Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples in any way. In the examples and comparative examples, "% " or "parts" is based on mass unless otherwise specified.

[0057] 3.1. Materials Used (1) Ethylene·α-olefin·non-conjugated polyene copolymer rubber For the ethylene·α-olefin·non-conjugated polyene copolymer rubber shown in Table 1 below, an oil-extended ethylene·α-olefin·non-conjugated polyene copolymer rubber (A)-1 containing a mineral oil-based softening agent (trade name "Diana Process Oil PW90", manufactured by Idemitsu Kosan Co., Ltd.) at the ratio shown in Table 1 below was used.

[0058]

Table 1

[0059] The limiting viscosity in Table 1 above is the value of the limiting viscosity of the ethylene·α-olefin·non-conjugated polyene copolymer rubber measured at a temperature of 135°C in a decalin solvent. Mw / Mn in Table 1 above was determined from the polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0060] (2) Polyolefin resin ·(B)-1: Polypropylene / ethylene / 1-butene random copolymer. Manufactured by Nippon Polypropylene Corporation, trade name "Novatec PP FW4BAT". ·(B)-2: Propylene / 1-butene amorphous copolymer, manufactured by Evonik Industries AG, trade name "VESTPLAST 508"

[0061] (3) Crosslinking agent ·(D): 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane, manufactured by NOF Corporation, trade name "Perhexa 25B-40"

[0062] (4) Crosslinking aid ·m-Phenylenebismaleimide, manufactured by Daiwa Kasei Kogyo Co., Ltd., trade name "BMI-3000"

[0063] (5) Antioxidant · Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), manufactured by ADEKA Corporation, trade name "ADEKA STAB AO-60"

[0064] (6) Light stabilizer · Tetrakis(1,2,2,6,6-pentamethylpiperidin-4-yl) butane-1,2,3,4-tetracarboxylate, manufactured by ADEKA Corporation, trade name "ADEKA STAB LA-52"

[0065] (7) Silicone oil · Dimethyl silicone oil, manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KF-96-100cs"

[0066] (8) Silicone masterbatch · Polypropylene resin silicone masterbatch, manufactured by Shin-Etsu Chemical Co., Ltd., product name "X-22-2101"

[0067] (9) Deodorant · (F-1): Copper-containing inorganic compound, manufactured by Toagosei Co., Ltd., product name "KESMON NS-20C" · (F-2): Zirconium compound, manufactured by Toagosei Co., Ltd., product name "KESMON NS-80E" · (F-3): Zirconium compound, manufactured by Toagosei Co., Ltd., product name "KESMON NS-10" · (F-4): Aluminum dihydrogen tripolyphosphate, manufactured by Teika Co., Ltd., product name "K-FRESH #100P"

[0068] 3.2. Example 1 3.2.1. Production of thermoplastic elastomer composition 74 parts by mass of an oil-extended ethylene·α-olefin·non-conjugated polyene copolymer rubber (A-1), 23 parts by mass of a polyolefin resin (B)-1, 3 parts by mass of a polyolefin resin (B)-2, 10 parts by mass of an additional mineral oil-based softening agent (C), 0.5 parts by mass of a crosslinking aid, 0.1 parts by mass of an antioxidant, 0.2 parts by mass of a light stabilizer, 1 part by mass of silicone oil, 3 parts by mass of a silicone masterbatch were charged into a 7-liter pressure kneader (manufactured by Nippon Spindle Co., Ltd., model "WDS7-30") heated to 150°C and kneaded at 60 rpm for 10 minutes. Then, the molten composition was pelletized using a twin-screw single-screw extruder (manufactured by Nippon Spindle Co., Ltd., model "2TR-75") set at 180°C and 20 rpm. 0.5 parts by mass of a crosslinking agent (D) was compounded into the obtained pellets, mixed for 30 seconds using a Henschel mixer, and extruded while performing a melt-kneading treatment under the conditions of 250°C, 500 rpm, and a residence time of 2 minutes using a twin-screw extruder (manufactured by Kobe Steel, Ltd., model "HYPERKTX 30", co-rotating fully intermeshing screw, the ratio of the length L of the screw flight part to the screw diameter D, L / D, is 74) to obtain pellets. Further, 0.5 parts by mass of an odor eliminator (F-1) was compounded into the obtained pellets, mixed for 30 seconds using a Henschel mixer, and extruded while performing a melt-kneading treatment under the conditions of 250°C, 500 rpm, and a residence time of 2 minutes using a twin-screw extruder (manufactured by Kobe Steel, Ltd., model "HYPERKTX 30", co-rotating fully intermeshing screw, the ratio of the length L of the screw flight part to the screw diameter D, L / D, is 74) to obtain a pelletized thermoplastic elastomer composition.

[0069] 3.2.2. Evaluation Method The obtained pelletized thermoplastic elastomer composition was injection molded into a flat plate of 120 mm × 120 mm × 2 mm (length × width × thickness) using an injection molding machine (manufactured by Nippon Steel Corporation, product name "J-110AD") with a clamping force of 110 tons to obtain test pieces. The odor intensity of the obtained test pieces was evaluated.

[0070] (*) Odor Intensity In accordance with VDA 270 B3, the odor intensity was evaluated in six grades from Grade 1 (odorless) to Grade 6 (intolerable odor). It can be judged that the smaller the grade number, the weaker the odor.

[0071] 3.3. Examples 2 to 7, Comparative Example 1 Pellet-shaped thermoplastic elastomer compositions and test pieces were prepared in the same manner as in Example 1 at the ratios shown in Table 2 below, and evaluated in the same manner as in Example 1.

[0072] 3.4. Evaluation Results Table 2 below shows the compositions and evaluation results of the thermoplastic elastomer compositions of each example and each comparative example.

[0073]

Table 2

[0074] From the evaluation results in Table 2 above, it was found that the thermoplastic elastomer compositions of Examples 1 to 7 had less odor than the thermoplastic elastomer composition of Comparative Example 1. In addition, all compositions could be molded without problems.

[0075] The present invention is not limited to the above-described embodiments, and various modifications are possible. The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations having the same functions, methods, and results, or configurations having the same purposes and effects). The present invention also includes configurations in which non-essential parts of the configurations described in the above embodiments are replaced with other configurations. Furthermore, the present invention includes configurations that exhibit the same operational effects as the configurations described in the above embodiments or configurations that can achieve the same purpose. Furthermore, the present invention also includes configurations in which known techniques are added to the configurations described in the above embodiments.

Claims

1. A thermoplastic elastomer composition obtained by melt-kneading an ethylene-α-olefin-non-conjugated polyene copolymer rubber (A), which is a copolymer of ethylene, an α-olefin having 3 to 20 carbon atoms, and a non-conjugated polyene, a polyolefin resin (B), and a mineral oil-based softener (C) in the presence of a crosslinking agent (D), and containing a deodorant (F).

2. The thermoplastic elastomer composition according to Claim 1, wherein the component (F) is at least one selected from the group consisting of silica, metal oxide particles, metal hydroxides, activated carbon, amine compounds, and phosphorus compounds.

3. The thermoplastic elastomer composition according to Claim 1, wherein when the total of the component (A), the above component (B), and the component (C) is 100 parts by mass, the content ratio of the component (F) is 0.1 to 20 parts by mass.

4. When the total of the component (A), the above component (B), and the component (C) is 100 parts by mass, The thermoplastic elastomer composition according to Claim 1, wherein the content ratio of the component (A) is 10 to 50 parts by mass, the content ratio of the component (B) is 1 to 15 parts by mass, the content ratio of the component (C) is 4 to 50 parts by mass, the content ratio of the component (D) is 10 to 50 parts by mass, and the content ratio of the component (F) is 0.1 to 20 parts by mass.

5. An automotive weatherstrip using at least partially the thermoplastic elastomer composition according to any one of Claims 1 to 4.

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