JP5140323B2 - Thermoplastic elastomer composition - Google Patents

Description

  The present invention relates to a thermoplastic elastomer composition.

  Conventional techniques for thermoplastic elastomer composition include melt-kneading a peroxide-crosslinked hydrocarbon rubber-like material and crystalline polyolefin and simply blending them, or performing dynamic crosslinking in the presence of organic peroxides. Has been manufactured. Furthermore, since only the peroxide-crosslinked hydrocarbon rubber-like substance and the crystalline polyolefin are insufficient in fluidity and low hardness, a peroxide non-crosslinked hydrocarbon rubber-like substance or mineral oil-based softener is used as a softener. Is used. (Patent Document 1)

  However, in recent vulcanized rubber and vinyl chloride substitutes, the use of peroxide non-crosslinked hydrocarbon rubber materials and mineral softeners to improve fluidity and hardness will improve fluidity and hardness sufficiently. The low molecular weight components of mineral non-crosslinked hydrocarbon rubber-like substances and mineral oil softeners bleed, resulting in a solid feeling in the molded product after aging, shine, and the gloss of the molded product changes. The problem was occurring.

Therefore, the appearance of a thermoplastic elastomer composition that does not cause shine due to the non-sticky surface of the molded product over time even in the presence of a low molecular weight component of a non-crosslinked hydrocarbon rubber-like substance or a mineral oil softener. Is desired.
Japanese Patent Publication No. 5-57297

The present invention is intended to solve the problems associated with the prior art as described above, be used charcoal hydrocarbon rubbery substance and mineral oil softening agent containing a low molecular weight component, after aging An object of the present invention is to provide a thermoplastic elastomer composition in which the surface of the molded article is not sticky.

The thermoplastic elastomer according to the present invention comprises 1-50 parts by weight of a hydrocarbon-based rubber-like substance (A) selected from butyl rubber, polyisobutylene, propylene-ethylene copolymer rubber having 70 mol% or more of propylene, a mineral oil-based softener (B) 1 to 70 parts by weight, 1 to 90 parts by weight of a peroxide-crosslinked hydrocarbon-based rubber-like substance , and a peroxide non-crosslinked polyolefin-based resin (excluding propylene-ethylene copolymer rubber having 70 mol% or more of propylene) .) With respect to 100 parts by weight of the thermoplastic elastomer (C) obtained by crosslinking 1 to 80 parts by weight of the organic peroxide, 0.1 to 10.0 parts by weight of the maleimide compound is melted in the absence of the organic peroxide. It is characterized by being kneaded. In particular, the maleimide compound is preferably N, N′-m-phenylenebismaleimide. Further, 100 parts by weight of the thermoplastic elastomer (C) is 1 to 50 parts by weight of a hydrocarbon rubber-like substance (A), 1 to 70 parts by weight of a mineral oil softener (B), a peroxide-crosslinked hydrocarbon rubber. It preferably comprises 1 to 90 parts by weight of a particulate material and 1 to 80 parts by weight of a peroxide non-crosslinked polyolefin resin. More preferably, the peroxide-crosslinked hydrocarbon-based rubber-like substance is partially or completely crosslinked. The hydrocarbon rubber-like substance (A) is preferably selected from polyisobutylene and butyl rubber.

  The thermoplastic elastomer composition according to the present invention is excellent in tactile sensation and appearance after aging of a molded product. As a molded article, it is used for applications such as automobile parts, industrial machine parts, electrical and electronic parts, civil engineering and building parts, medical parts, etc., and a molded article having an appearance that does not have any problem even when used for a long time is obtained.

  Hereinafter, the thermoplastic elastomer composition according to the present invention and its use will be specifically described.

Hydrocarbon rubber-like substance (A)
The charcoal hydrocarbon rubbery substance Te present invention smell (A), for example, butyl rubber, polyisobutylene, propylene 70 mol% or more of propylene - selected from ethylene copolymer rubber is mixed with peroxide, kneading with heating Even if it does not bridge | crosslink, it says the hydrocarbon-type rubber-like substance which does not fall fluidity. Of these, polyisobutylene and butyl rubber are preferable in terms of performance and handling. In the present invention, the term “crosslinking” refers to a phenomenon in which a crosslinking reaction occurs in a competitive reaction between a decomposition reaction and a crosslinking reaction that occur when a polymer is thermally reacted with an organic peroxide. A reaction phenomenon in which the apparent molecular weight of a polymer decreases . Preferably in that Mooney viscosity of coal hydrocarbon rubbery substance (A) is 60 or less to improve the flowability of the composition, particularly preferred in the case of polyisobutylene or butyl rubber. The amount of coal hydrocarbon rubbery substance (A) is a thermoplastic elastomer (C) 1 to 50 parts by weight in 100 parts by weight, preferably 5 to 40 parts by weight.

Mineral oil softener (B)
The mineral oil-based softener (B) in the present invention usually weakens the intermolecular force at the time of roll processing of rubber, facilitates processing, helps disperse carbon black, white carbon, etc., or vulcanized rubber It is a high-boiling petroleum fraction used for the purpose of reducing the hardness and increasing flexibility and elasticity, and is classified into paraffinic, naphthenic or aromatic. The blending amount of the mineral oil softener in the present invention is 1 to 70 parts by weight, preferably 5 to 60 parts by weight, more preferably 10 to 50 parts by weight, in 100 parts by weight of the total amount of the thermoplastic elastomer components.

  In the present invention, when the mineral oil-based softening agent (B) is used in the above proportion, the resulting thermoplastic elastomer composition (D) of the present invention has excellent fluidity during molding, and the molding machine The physical properties are not reduced. In the present invention, the mineral oil softener (B) may be added during the production of the thermoplastic elastomer (C), or may be previously oil-extended into a peroxide-crosslinked hydrocarbon rubber-like substance.

Thermoplastic elastomer (C)
As the thermoplastic elastomer in the present invention (C), carbon hydrocarbon rubbery substance (A), it is essential to contain mineral oil-based softener (B), further to peroxide crosslinked type hydrocarbon rubber include Jo substance 1 to 90 parts by weight and the peroxide non-crosslinked type olefinic resin 1-80 parts by weight, a thermoplastic elastomer a peroxide crosslinking type hydrocarbon rubbery substance is partially or completely crosslinked (C).

[Peroxide non-crosslinked polyolefin resin]
Peroxide non-crosslinked polyolefin resin used as a component of the thermoplastic elastomer (C) ( excluding propylene-ethylene copolymer rubber with 70 mol% or more of propylene) is either a high pressure method or a low pressure method . A crystalline high molecular weight solid product obtained by polymerizing one or more monoolefins by a method. Examples of such a peroxide non-crosslinked polyolefin resin include isotactic and syndiotactic monoolefin polymer resins. These representative resins are commercially available.

  Specific examples of suitable raw material olefins for the above-mentioned peroxide non-crosslinked polyolefin resin include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 2-methyl-1- Examples thereof include α-olefins having 2 to 20 carbon atoms, preferably 2 to 12 carbon atoms such as propene, 3-methyl-1-pentene, 4-methyl-1-pentene, and 5-methyl-1-hexene. These α-olefins are used alone or in combination of two or more.

  The polymerization mode may be random type or block type, and any polymerization mode can be adopted as long as a resinous material is obtained.

  As the peroxide non-crosslinked polyolefin resin, a propylene polymer is preferable, and specifically, a propylene homopolymer, a propylene / ethylene block copolymer, propylene / ethylene, and a propylene / ethylene / butene random copolymer are preferable.

The peroxide non-crosslinked polyolefin resin has a melt flow rate (MFR: ASTM D 1238-65T, 230 ° C., 2.16 kg load) usually 0.01 to 100 g / 10 min, preferably 0.05 to 50 g / 10 min. It is desirable to be in the range.
The peroxide non-crosslinked polyolefin-based resin has a role of improving the fluidity and heat resistance of the thermoplastic elastomer composition (D) of the present invention. Peroxide non-crosslinked polyolefin resins may be used alone or in combination of two or more. Although there is no restriction | limiting in particular as said peroxide non-crosslinking type polyolefin resin, A polypropylene etc. can be illustrated and especially a polypropylene is preferable.

[Peroxide-crosslinked hydrocarbon-based rubber-like material]
The peroxide-crosslinked hydrocarbon rubber-like substance used as a component of the thermoplastic elastomer (C) is not particularly limited, but ethylene / α-olefin / non-conjugated polyene copolymers such as ethylene / α-olefin / non-conjugated polyene copolymers Examples include polyene copolymers and ethylene / α-olefin copolymers.

 The ethylene content of the ethylene / α-olefin (• non-conjugated polyene) copolymer rubber is usually 25 to 95 mol%, preferably 30 to 90 mol%, and more preferably 35 to 85 mol%.

  Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 2-methyl-1-propene, 3-methyl-1-pentene and 4-methyl-1- Although C3-C20 alpha olefins, such as pentene and 5-methyl-1-hexene, are mentioned, Propylene is especially preferable.

Further, as the non-conjugated polyene, specifically,
1,4-hexadiene, 3-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 4,5-dimethyl-1,4-hexadiene, 7- Linear unconjugated dienes such as methyl-1,6-octadiene, 8-methyl-4-ethylidene-1,7-nonadiene, 4-ethylidene-1,7-undecadiene;
Methyltetrahydroindene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 5-vinylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene Cyclic non-conjugated dienes such as 5-vinyl-2-norbornene, 5-isopropenyl-2-norbornene, 5-isobutenyl-2-norbornene, cyclopentadiene, norbornadiene;
2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,2-norbornadiene, 4-ethylidene-8-methyl-1,7-nanodiene, etc. And triene. Of these, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, cyclopentadiene, and 4-ethylidene-8-methyl-1,7-nanodiene are preferable.

The ethylene / α-olefin (• nonconjugated polyene) copolymer rubber preferably has an iodine value of 1 to 30 g / 100 g, more preferably 3 to 25 g / 100 g. Moreover, it is preferable that Mooney viscosity (ML1 _{+ 4} , 100 degreeC) is 10-250.

  The use ratio of the peroxide non-crosslinked polyolefin resin and the peroxide cross-linked hydrocarbon rubber-like substance is such that the peroxide non-crosslinked polyolefin resin is 1 to 80 weights in a total of 100 parts by weight of all the components of the thermoplastic elastomer (C). Parts, preferably 15 to 60 parts by weight, and 1 to 90 parts by weight, preferably 45 to 80 parts by weight of peroxide-crosslinked hydrocarbon-based rubber-like substance. When the usage ratio of the peroxide non-crosslinked polyolefin resin and the peroxide cross-linked hydrocarbon rubber-like substance is in the above range, the heat-resistant thermoplastic elastomer composition of the present invention is excellent in flexibility and rubber elasticity and excellent in molding processing. A thing is obtained.

  In addition, the peroxide-crosslinked hydrocarbon-based rubber-like substance of the present application is used by pre-oiling or adding a softener and an inorganic filler that are usually used for rubber, such as a mineral oil-based softener and an inorganic filler. Can do. As the mineral oil-based softener, 0 to 150 parts by weight of oil may be extended with respect to 100 parts by weight of the peroxide-crosslinked hydrocarbon-based rubber-like substance.

Maleimide Compound As the maleimide compound according to the present invention, N, N′-m-phenylene bismaleimide, N, N′-toluylene bismaleimide and the like can be raised. preferable.

  The amount of the maleimide compound added to 100 parts by weight of the thermoplastic elastomer (C) is 0.1 to 10.0 parts by weight, preferably 0.2 to 5.0 parts by weight, more preferably 0.3 parts by weight. Parts to 2.5 parts by weight.

  The maleimide compound in the present invention is added in the absence of an organic peroxide, unlike the case where it is usually used as a crosslinking aid. When used in combination with an organic peroxide, a crosslinking reaction occurs, and the physical properties of the thermoplastic elastomer (C) are affected.

  Further, the addition of the maleimide compound in the present invention is preferably carried out in a non-open type apparatus, and is preferably carried out in an inert gas atmosphere such as nitrogen or carbon dioxide.

  Here, as a method for adding the maleimide compound to the thermoplastic elastomer, dry blending may be performed before molding, but kneading in a molten state is preferable from the viewpoint of dispersion.

The kneading temperature is usually 150 to 280 ° C, preferably 170 to 240 ° C. The kneading time is usually 1 to 20 minutes, preferably 3 to 10 minutes. Further, the shear force applied is, 10～100,000Sec ^-1 as the shear rate is preferably 100~50,000sec ^-1.

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

Other components When a maleimide compound is added to the thermoplastic elastomer according to the present invention, additives such as slip agents, fillers, antioxidants, weathering stabilizers, colorants, foaming agents, etc. It can mix | blend in the range which does not impair the objective of invention.

  Examples of the slip agent include fatty acid amide, silicone oil, glycerin, wax, and paraffinic oil.

  Examples of the filler include conventionally known fillers, specifically, carbon black, clay, talc, calcium carbonate, kaolin, diatomaceous earth, silica, alumina, graphite, glass fiber and the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited at all by these Examples.

The evaluation was performed according to the following method.
(1) Hardness As for hardness, Shore A hardness was measured in accordance with JIS K6253.
(Measurement conditions) A sheet was prepared by a press molding machine, and the scale was read immediately after contact with the pressing needle using an A-type measuring instrument.
(2) Solid of molded article over time About the composition pellet obtained by the Example and the comparative example, the injection temperature is 250 degreeC and the mold temperature is 40 degreeC with the Sumitomo Heavy Industries Co., Ltd. vertical 50t injection molding machine. A molded product having a length of 10 cm, a width of 2 mm, and a thickness of 2 mm was prepared. The molded product was left in an oven at 80 ° C. for 10 days, and then the solid feeling of the molded product was examined.

[Reference example]
Preparation of thermoplastic elastomer ( preparation of thermoplastic elastomer pellet-1)
As a peroxide-crosslinked hydrocarbon-based rubber-like substance, oil-extended ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber [ethylene content: 78 mol%, propylene content: 22 mol%, iodine value: 13, Mooney viscosity [ML _{1 + 4} (100 ° C.)] 74, oil extended amount: 40 parts by weight of paraffinic process oil (manufactured by Idemitsu Kosan Co., Ltd., trade name PW-380) with respect to 100 parts by weight of rubber; Abbreviated. ] 70 parts by weight;
As a peroxide non-crosslinked polyolefin resin, propylene homopolymer [MFR (ASTM D 1238, 230 ° C., 2.16 kg load): 0.5 g / 10 min, melting point (Tm): 162 ° C .; hereinafter abbreviated as PP-1. . ] 15 parts by weight,
15 parts by weight of Butyl065 (manufactured by Nippon Butyl Co., Ltd. ) as a hydrocarbon rubber-like substance (A) 0.1 parts by weight of a phenolic antioxidant [manufactured by Ciba Geigy Japan, Inc., trade name: Irganox 1010] And
0.1 parts by weight of a diazo weathering stabilizer [Nippon Ciba-Geigy Co., Ltd., trade name: Tinuvin 326] as a weathering agent,
As a cross-linking agent, 0.2 part by weight of an organic peroxide [manufactured by Nippon Oil & Fats Co., Ltd., trade name Perhexa 25B] was sufficiently mixed with a Henschel mixer, and an extruder [product number TEM-50, manufactured by Toshiba Machine Co., Ltd., L / D = 40, cylinder temperature: C1-C2 120 ° C., C3-C4 140 ° C., C5-C6 180 ° C., C7-C8 200 ° C., C9-C12 220 ° C., die temperature: 210 ° C., screw rotation speed: 280 rpm, extrusion rate: At 40 kg / h], granulation is performed while injecting 10 parts by weight of paraffinic process oil [trade name PW-100, manufactured by Idemitsu Kosan Co., Ltd.] into a cylinder, and first, a pellet-1 of a thermoplastic elastomer composition is obtained. It was.

(Preparation of thermoplastic elastomer pellet-2)
As a peroxide-crosslinked hydrocarbon-based rubber-like substance, oil-extended ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber [ethylene content: 78 mol%, propylene content: 22 mol%, iodine value: 13, Mooney viscosity [ML _{1 + 4} (100 ° C.)] 74, oil extended amount: 40 parts by weight of paraffinic process oil (manufactured by Idemitsu Kosan Co., Ltd., trade name PW-380) with respect to 100 parts by weight of rubber; Abbreviated. ] 70 parts by weight;
As a peroxide non-crosslinked polyolefin resin, propylene homopolymer [MFR (ASTM D 1238, 230 ° C., 2.16 kg load): 0.5 g / 10 min, melting point (Tm): 162 ° C .; hereinafter abbreviated as PP-1. . ] 15 parts by weight,
15 parts by weight of Butyl065 (manufactured by Nippon Butyl Co., Ltd.) as a hydrocarbon rubber-like substance, 0.1 parts by weight of a phenolic antioxidant [Nippon Ciba Geigy Co., Ltd., trade name: Irganox 1010] as an antioxidant;
0.1 parts by weight of a diazo weathering stabilizer [Nippon Ciba-Geigy Co., Ltd., trade name: Tinuvin 326] as a weathering agent,
As a cross-linking agent, 0.2 part by weight of an organic peroxide [manufactured by Nippon Oil & Fats Co., Ltd., trade name Perhexa 25B] was sufficiently mixed with a Henschel mixer, and an extruder [product number TEM-50, manufactured by Toshiba Machine Co., Ltd., L / D = 40, cylinder temperature: C1-C2 120 ° C., C3-C4 140 ° C., C5-C6 180 ° C., C7-C8 200 ° C., C9-C12 220 ° C., die temperature: 210 ° C., screw rotation speed: 280 rpm, extrusion rate: At 40 kg / h], granulation is performed while injecting 25 parts by weight of paraffinic process oil [trade name PW-100, manufactured by Idemitsu Kosan Co., Ltd.] into a cylinder, and first, pellet 1 of a thermoplastic elastomer composition is obtained. It was.

(Preparation of thermoplastic elastomer pellet-3)
Oil-extended ethylene / propylene / 5-ethylidene-2-norbornene copolymer rubber [ethylene content: 78 mol%, propylene content: 22 mol%, iodine value: 13, Mooney viscosity [ML _{1 + 4} (100 ° C. ], 74, oil extended amount: 40 parts by weight of paraffinic process oil (trade name PW-380, manufactured by Idemitsu Kosan Co., Ltd.) with respect to 100 parts by weight of rubber; hereinafter abbreviated as EPT. ] 70 parts by weight;
Propylene homopolymer as peroxide non-crosslinked polyolefin resin [MFR (ASTM D 1238, 230 ° C., 2.16 kg load): 1.5 g / 10 min, melting point (Tm): 162 ° C .; hereinafter abbreviated as PP-1. ] 30 parts by weight,
0.1 part by weight of a phenolic antioxidant [Nippon Ciba Geigy Co., Ltd., trade name: Irganox 1010] as an antioxidant,
0.1 parts by weight of a diazo weathering stabilizer [Nippon Ciba-Geigy Co., Ltd., trade name: Tinuvin 326] as a weathering agent,
As a cross-linking agent, 0.2 part by weight of an organic peroxide [manufactured by Nippon Oil & Fats Co., Ltd., trade name Perhexa 25B] was sufficiently mixed with a Henschel mixer, and an extruder [product number TEM-50, manufactured by Toshiba Machine Co., Ltd., L / D = 40, cylinder temperature: C1-C2 120 ° C., C3-C4 140 ° C., C5-C6 180 ° C., C7-C8 200 ° C., C9-C12 220 ° C., die temperature: 210 ° C., screw rotation speed: 280 rpm, extrusion rate: At 40 kg / h], granulation is performed while injecting 10 parts by weight of paraffinic process oil [product name PW-100, manufactured by Idemitsu Kosan Co., Ltd.] into the cylinder, and first, pellet 2 of a thermoplastic elastomer composition is obtained. It was.

[Example 1]
100 parts by weight of the thermoplastic elastomer pellet-1 prepared in the reference example and 2.2 parts by weight of N, N′-m-phenylenebismaleimide are sufficiently mixed with a Henschel mixer, and an extruder [product number TEM-50, Toshiba Machine ( Co., Ltd., L / D = 40, cylinder temperature: C1-C4 160 ° C., C5-C12 200 ° C., die temperature: 210 ° C., screw rotation speed: 280 rpm, extrusion rate: 40 kg / h] First, pellets of a thermoplastic elastomer composition were obtained.
This pellet-shaped thermoplastic elastomer composition was evaluated according to the method described above.
As a result, the hardness was A55, and the molded product was not solid after aging.

[Example 2]
In Example 1, pellets of a thermoplastic elastomer composition were obtained in the same manner as in Example 1 except that the amount of maleimide compound added was 5.3 parts by weight.
As a result, the hardness was A56, and the molded product was not solid after aging.

[Example 3]
A pellet of a thermoplastic elastomer composition was obtained in the same manner as in Example 1 except that the thermoplastic elastomer pellet-2 was used instead of the thermoplastic elastomer pellet-1 in Example 1.
As a result, the hardness was A41, and the molded product was not solid after aging.

[Comparative Example 1]
The pellets of the thermoplastic elastomer composition were obtained in the same manner as in Example 1 without adding the maleimide compound in Example 1.
As a result, the hardness was A54, and solids were observed in the molded product after aging.

[Comparative Example 2]
A pellet of the thermoplastic elastomer composition was obtained in the same manner as in Example 1 except that the maleimide compound was not added in Example 1 and that the thermoplastic elastomer pellet-3 was used instead of the thermoplastic elastomer pellet-1.
As a result, the hardness was A80, and no solidity was found in the molded product after a lapse of time, but a reduction in hardness could not be realized.

Claims (4)

1 to 50 parts by weight of a hydrocarbon-based rubber-like substance (A) selected from butyl rubber, polyisobutylene, propylene-ethylene copolymer rubber having 70 mol% or more of propylene, 1 to 70 parts by weight of a mineral oil-based softener (B), 1 to 90 parts by weight of a peroxide-crosslinked hydrocarbon rubber-like substance and 1 to 80 parts by weight of a peroxide non-crosslinked polyolefin resin (excluding propylene-ethylene copolymer rubber of 70 mol% or more of propylene) It is characterized in that 0.1 to 10.0 parts by weight of a maleimide compound is melt-kneaded in the absence of an organic peroxide with respect to 100 parts by weight of a thermoplastic elastomer (C) obtained by crosslinking with a peroxide. Thermoplastic elastomer composition (D).   The thermoplastic elastomer composition (D) according to claim 1, wherein the maleimide compound is N, N'-m-phenylenebismaleimide.   The thermoplastic elastomer composition (D) according to claim 1 or 2, wherein the peroxide-crosslinked hydrocarbon-based rubber-like substance of the thermoplastic elastomer (C) is partially or completely crosslinked.   The thermoplastic elastomer composition (D) according to any one of claims 1 to 3, wherein the hydrocarbon rubber-like substance (A) is at least one selected from polyisobutylene and butyl rubber.