JP2018154821A - Thermoplastic elastomer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition having excellent compression set.SOLUTION: A thermoplastic elastomer composition contains a propylene polymer (A) having a long-chain branch structure, an ethylene α-olefin nonconjugated diene copolymer (B) having a Mooney viscosity ML(125°C) of 45 or more, and a hydrocarbon rubber softener (C). The propylene polymer (A) satisfies the following requirements (A-1). In (A-1)C-NMR analysis, methylene carbon (Ca, Cb, Cc) is observed in each of 44.0-44.1 ppm, 44.7-44.8 ppm and 44.8-44.9 ppm, and methine carbon (Cbr) is observed in 31.6-31.7 ppm.SELECTED DRAWING: None

Description

  The present invention relates to a thermoplastic elastomer composition excellent in compression set and a molded body formed by molding this thermoplastic elastomer composition.

  The thermoplastic elastomer refers to an elastomer that is softened by heating and has fluidity, and has rubber elasticity when cooled. Specifically, at the time of molding, it can be melted at the processing temperature and can be easily molded in the same manner as a known thermoplastic resin, but the temperature actually used as various materials after the molding process. Has the same physical properties as the crosslinked rubber. Thus, the thermoplastic elastomer has molding processability similar to that of a thermoplastic resin, has a unique rubber elasticity, and can be recycled, so that it can be used for automobile parts, building parts, medical parts, Widely used in applications such as wire covering materials and sundries.

  When a thermoplastic elastomer composition is used as a substitute for vulcanized rubber, it is particularly important to have good rubber elasticity or compression set characteristics, and many studies have been made. As an example, Patent Document 1 discloses a thermoplastic elastomer composition containing a propylene polymer, an ethylene / α-olefin / non-conjugated polyene copolymer rubber, and dynamically crosslinked with an organic peroxide in an extruder. Patent Document 2 discloses a thermoplastic elastomer composition containing an olefin copolymer rubber, crystalline polypropylene, and an inorganic filler and crosslinked with a non-halogen phenol resin crosslinking agent. However, these prior arts are insufficient in practical use, and there is a demand for a thermoplastic elastomer composition having more excellent compression set.

  On the other hand, Patent Documents 3 to 5 disclose polymerization-type modified polypropylene having a long-chain branched structure. Patent Document 6 discloses a propylene-based resin composition obtained by adding ethylene / α-olefin rubber to modified polypropylene having a long-chain branched structure described in Patent Documents 3 to 5. Patent document 6 describes the improvement of rigidity, impact resistance, drawdown resistance, and thermal stability as its effect, but there is no description that compression set is improved by ethylene / α-olefin rubber. .

A composition obtained by adding an ethylene / α-olefin / non-conjugated diene copolymer having a Mooney viscosity ML _{1 + 4} (125 ° C.) of 45 or more to a modified polypropylene having a long-chain branched structure described in Patent Documents 3 to 5 is as follows: Although it is a known technique in Patent Document 6, there is a problem that the mixture of only these two components cannot be kneaded at the torque neck.

JP 2006-265319 A JP 2009-275213 A JP 2009-299045 A JP 2007-154121 A JP 2009-40959 A JP 2009-275147 A

  An object of this invention is to provide the thermoplastic elastomer composition excellent in compression set, and the molded object formed by shape | molding this thermoplastic elastomer composition.

As a result of studies conducted by the present inventors to solve the above problems, a thermoplastic elastomer containing a propylene polymer and an ethylene / α-olefin / non-conjugated diene copolymer having a Mooney viscosity ML _{1 + 4} (125 ° C.) of 45 or more. It was confirmed that the compression set is improved by replacing the propylene homopolymer of the composition with a modified polypropylene having a long-chain branched structure. Although the detailed mechanism of the effect of improving the compression set is unknown, it is presumed from the fact that such an effect is obtained that the propylene polymer having a long chain branched structure of the component (A) is used as a nucleating agent or a phase. It is considered that the compression set has been improved by functioning as an inversion accelerator.
Moreover, the problem of torque neck was improved by adding a hydrocarbon-based rubber softener, and the problem that could not be achieved in the past could be solved.

  That is, the gist of the present invention is as follows.

[1] Propylene polymer (A) having a long-chain branched structure, ethylene / α-olefin / non-conjugated diene copolymer (B) having a Mooney viscosity ML _{1 + 4} (125 ° C.) of 45 or more, and hydrocarbon rubber A thermoplastic elastomer composition comprising a softener (C), wherein the propylene polymer (A) satisfies the following requirement (A-1).
(A-1) In ¹³ C-NMR analysis, methylene carbon (Ca, Cb, Cc) was observed at 44.0-44.1 ppm, 44.7-44.8 ppm, and 44.8-44.9 ppm, respectively. Methine carbon (Cbr) is observed at 31.6-31.7 ppm.

[2] Propylene heavy polymer having a long chain branched structure in a total of 100 parts by mass of the propylene polymer (A) having a long chain branched structure and the ethylene / α-olefin / nonconjugated diene copolymer (B). Propylene-based heavy having a long chain branched structure containing 1 part by mass or more and less than 50 parts by mass of the blend (A), more than 50 parts by mass and 99 parts by mass or less of the ethylene / α-olefin / nonconjugated diene copolymer (B). [20] The hydrocarbon rubber softener (C) is contained in an amount of 20 parts by mass or more with respect to a total of 100 parts by mass of the blend (A) and the ethylene / α-olefin / non-conjugated diene copolymer (B). Thermoplastic elastomer composition

[3] The thermoplastic elastomer according to [1] or [2], wherein the propylene-based polymer (A) has a branching index g ′ in the range of 0.75 or more and 0.95 or less when the absolute molecular weight Mabs is 1,000,000. Composition.

[4] The crosslinking agent (D) is contained in an amount of 0.1 to 10 parts by mass with respect to 100 parts by mass of the ethylene / α-olefin / non-conjugated diene copolymer (B). The thermoplastic elastomer composition according to any one of the above.

[5] The thermoplastic elastomer composition according to [4], wherein the crosslinking agent (D) is an organic peroxide and / or a phenol resin.

[6] Ethylene / propylene / ethylidene norbornene in which the ethylene / α-olefin / nonconjugated diene copolymer (B) has an ethylene unit content of 30 to 90% by mass and a nonconjugated diene unit content of 1 to 10% by mass and / or Alternatively, the thermoplastic elastomer composition according to any one of [1] to [4], which is a vinylidene norbornene copolymer.

[7] The thermoplastic elastomer composition according to any one of [1] to [6], wherein the hydrocarbon rubber softener (C) is a paraffin oil having a kinematic viscosity at 40 ° C. of 20 to 800 centistokes. .

[8] The thermoplastic elastomer composition according to any one of [1] to [7], which is a composition for non-foamed molded articles.

[9] A molded article obtained by molding the thermoplastic elastomer composition according to any one of [1] to [8].

The thermoplastic elastomer composition of the present invention is excellent in compression set. For this reason, the thermoplastic elastomer composition of the present invention is particularly suitable as a composition for non-foamed molded articles and is industrially very useful as a substitute for a crosslinked rubber having excellent molding processability.
In addition, since the surface roughness value of the molded product can be improved, the deterioration of the surface appearance due to the occurrence of bumps (foreign matter, hypercrosslinked product, etc. appearing on the molded product surface) is reduced, and the surface of the molded product is reduced. It is expected to contribute to uniformity and design.

  The thermoplastic elastomer composition of the present invention can be suitably used in automotive fields such as seals, cushions, boots, and skins; architectural fields such as gaskets and packings; miscellaneous goods fields such as grips and casters.

  Embodiments of the present invention will be described in detail below, but the following descriptions are representative examples of embodiments of the present invention, and the present invention is not limited to these contents. In the present invention, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

[Thermoplastic elastomer composition]
The thermoplastic elastomer composition of the present invention comprises a propylene polymer (A) having a long-chain branched structure, an ethylene / α-olefin / non-conjugated diene copolymer (B) having a Mooney viscosity ML _{1 + 4} (125 ° C.) of 45 or more. And a thermoplastic elastomer composition containing a hydrocarbon rubber softener (C), wherein the propylene polymer (A) satisfies the following requirement (A-1).
(A-1) In ¹³ C-NMR analysis, methylene carbon (Ca, Cb, Cc) was observed at 44.0-44.1 ppm, 44.7-44.8 ppm, and 44.8-44.9 ppm, respectively. Methine carbon (Cbr) is observed at 31.6-31.7 ppm.

[Propylene polymer having long-chain branched structure (A)]
The propylene polymer (A) used in the present invention (sometimes referred to as “component (A)” in the present invention) has a specific long-chain branched structure. The details will be described below.

< ^13C -NMR>
Methylene carbon (Ca, Cb, Cc) was observed at 44.0 to 44.1 ppm, 44.7 to 44.8 ppm, and 44.8 to 44.9 ppm in ¹³ C-NMR measurement (that is, 44.0 to 44.0). Methylene carbon (Ca) was observed at 44.1 ppm, methylene carbon (Cb) was observed at 44.7-44.8 ppm, and methylene carbon (Cc) was observed at 44.8-44.9 ppm. Two methylene carbons are observed.) The observation of methine carbon (Cbr) at 31.6 to 31.7 ppm indicates that the propylene polymer (A) has a long-chain branched structure with branched carbons. .

  For this feature, Macromol. Chem. Phys. 2003, vol. Detailed descriptions are given in 204 and 1738 as follows.

The propylene-based polymer having a long chain branched structure has a specific branched structure as shown in the following structural formula (1). In Structural Formula (1), C _a , C _b , and C _c represent methylene carbon adjacent to the branched carbon, C _br represents the methine carbon at the root of the branched chain, and P ¹ , P ² , and P ³ represent Represents a propylene-based polymer residue.
P ¹ , P ² , and P ³ may contain a branched carbon (C _br ) different from C _br described in the structural formula (1) in itself.

Such a branched structure is identified by ¹³ C-NMR analysis. The assignment of each peak is described in Macromolecules, Vol. 35, no. 10. The description of 2002, pages 3839-3842 can be referred to. That is, a total of three methylene carbons (C _a , C _b , C _c ) are observed, each at 43.9-44.1 ppm, 44.5-44.7 ppm, and 44.7-44.9 ppm, Methine carbon (C _br ) is observed at 31.5-31.7 ppm. Hereinafter, the methine carbon observed at 31.5 to 31.7 ppm may be abbreviated as branched methine carbon (C _br ).
The feature is that three methylene carbons adjacent to the branched methine carbon C _br are observed in a diastereotopic manner and divided into three non-equivalents.

Such a branched chain assigned by ¹³ C-NMR indicates a propylene-based polymer residue having 5 or more carbon atoms branched from the main chain of the propylene-based polymer, and this and a branch having 4 or less carbon atoms are branched. Since the carbon peak positions can be distinguished from each other, in the present invention, the presence or absence of a long-chain branched structure can be determined by confirming the peak of the branched methine carbon.
In addition, about the measuring method of ¹³ C-NMR in this invention, it is as follows.

< ^13C -NMR measurement method>
A 200 mg sample is an NMR sample having an inner diameter of 10 mmφ together with 2.4 ml of o-dichlorobenzene / deuterated benzene bromide (C ₆ D ₅ Br) = 4/1 (volume ratio) and hexamethyldisiloxane which is a reference substance of chemical shift Dissolve in a tube and perform ¹³ C-NMR measurement.
^{The 13} C-NMR measurement is performed using an AV400M NMR apparatus manufactured by Bruker BioSpin Co., Ltd. equipped with a 10 mmφ cryoprobe.
The measurement is carried out by a proton complete decoupling method at a sample temperature of 120 ° C. Other conditions are as follows.
Pulse angle: 90 °
Pulse interval: 4 seconds Integration frequency: 20000 times The chemical shift was set at 1.98 ppm for the methyl carbon peak of hexamethyldisiloxane, and the chemical shifts for peaks due to other carbons were based on this.
The long chain branching amount can be calculated using a peak around 44 ppm.

The propylene polymer (A) has a long chain branching amount determined from a peak around 44 ppm of the ¹³ C-NMR spectrum of 0.01 / 1000 total propylene (per 1000 total skeleton-forming carbons) or more. More preferably, 0.03 / 1000 total propylene or more, and still more preferably 0.05 / 1000 total propylene or more. On the other hand, the number is preferably 1.00 / 1000 total propylene or less, more preferably 0.50 / 1000 total propylene, and still more preferably 0.30 / 1000 total propylene. When the long-chain branching amount is within this range, a polypropylene resin having a high degree of strain hardening and no gel can be obtained.

<Branching index g '>
The propylene polymer (A) in the present invention has a branching index g ′ known as a direct index for long-chain branching of an absolute molecular weight Mabs of 1,000,000, and the lower limit is preferably 0.3 or more and 0.55 or more in order of preference. 0.75 or more and 0.78 or more, and the upper limit is less than 1.0, 0.98 or less, 0.96 or less, or 0.95 or less in order of preference, and the lower limit and the upper limit are in any combination. Can do. When the branching index g ′ is in a range between any of the above preferred lower limits and any of the above preferred upper limits, a highly crosslinked component is not formed, which is preferable in terms of molding appearance. The most preferable range of the branching index g ′ in the present invention is 0.78 or more and 0.95 or less.

  The branching index g ′ is known as a direct index for long chain branching. There is a detailed description in “Developments in Polymer Characterization-4” (JV Dawkins ed. Applied Science Publishers, 1983). The definition of the branching index g ′ is as follows.

Branch index g ′: [η] br / [η] lin
[Η] br: Intrinsic viscosity of the polymer (br) having a long-chain branched structure [η] lin: Intrinsic viscosity of a linear polymer having the same molecular weight as the polymer (br)

  As is clear from the above definition, when the branching index g ′ takes a value smaller than 1, it is determined that a long chain branching structure exists, and the value of the branching index g ′ decreases as the long chain branching structure increases. .

  The branching index g ′ can be obtained as a function of the absolute molecular weight Mabs by using GPC with a light scatterometer and viscometer in the detector. The method for measuring the branching index g ′ in the present invention is described in detail in JP-A-2015-40213, but is as follows.

<Measurement method>
GPC: Alliance GPCV2000 (Waters)
Detector: Described in the order of connection Multi-angle laser light scattering detector (MALLS): DAWN-E (Wyatt Technology)
Differential refractometer (RI): attached to GPC Viscometer (Viscometer): attached to GPC Mobile phase solvent: 1,2,4-trichlorobenzene (Irganox 1076 added at a concentration of 0.5 mg / mL)
Mobile phase flow rate: 1 mL / min Column: Tosoh Corporation GMHHR-H (S) Two HT connections Sample injection part temperature: 140 ° C.
Column temperature: 140 ° C
Detector temperature: 140 ° C for all
Sample concentration: 1 mg / mL
Injection volume (sample loop volume): 0.2175 mL

<Analysis method>
When calculating the absolute molecular weight (Mabs) obtained from the multi-angle laser light scattering detector (MALLS), the root mean square radius of inertia (Rg), and the intrinsic viscosity ([η]) obtained from the Viscometer, data processing attached to MALLS Calculation is performed using the software ASTRA (version 4.73.04) with reference to the following document.
References:
1. “Developments in Polymer Characterization-4” (JV Dawkins ed. Applied Science Publishers, 1983. Chapter 1.)
2. Polymer, 45, 6495-6505 (2004).
3. Macromolecules, 33, 2424-2436 (2000)
4). Macromolecules, 33, 6945-6952 (2000)

<MFR>
For the propylene polymer (A) having a long-chain branched structure, a melt flow rate (MFR) (230 ° C., measured at a measurement temperature of 230 ° C. and a measurement load of 21.2 N according to JIS K7210 (1999). 21.2N) is preferably 100 g / 10 min or less in order to prevent the occurrence of burrs during injection molding, and more preferably 30 g / in order to prevent the occurrence of burrs during injection molding and the drawdown during extrusion molding. 10 minutes or less.

  The propylene polymer (A) having such a long chain branched structure is produced by a method using a macromer copolymerization method in which a long chain branched structure is formed during polymerization. Examples of this method include, for example, JP-T-2001-525460, JP-A-10-338717, JP-A-2002-523575, JP-A-2009-57542, JP-A-05027353, JP-A-10 The method etc. which are indicated by -338717 gazette are mentioned. In particular, the macromer copolymerization method disclosed in JP2009-57542A is suitable for the present invention.

The propylene polymer (A) can be suitably used in the present invention as long as it satisfies the above-mentioned regulations, and only one type may be used or two or more types may be used.
As the propylene polymer (A) satisfying this rule, various grades of WAYMAX ^TM series manufactured by Nippon Polypro Co., Ltd. are available.

[Ethylene / α-olefin / non-conjugated diene copolymer (B)]
The ethylene / α-olefin / non-conjugated diene copolymer (B) used in the present invention (sometimes referred to as “component (B)” in the present invention) has a Mooney viscosity ML _{1 + 4} (125 ° C.) of 45. The above ethylene / α-olefin / non-conjugated diene copolymer.

  As the α-olefin unit in the component (B), propylene unit, 1-butene unit, 2-methylpropylene unit, 1-pentene unit, 3-methyl-1-butene unit, 1-hexene unit, 4-methyl-1 -A pentene unit, 1-octene unit, etc. can be illustrated. Among these, an α-olefin unit is preferably an α-olefin unit having 3 to 10 carbon atoms, and more preferably a propylene unit, a 1-butene unit, a 1-hexene unit, or a 1-octene unit. The α-olefin unit may contain only one type or two or more types.

  As the non-conjugated diene unit in the ethylene / α-olefin / non-conjugated diene copolymer of component (B), a dicyclopentadiene unit, a 1,4-hexadiene unit, a cyclooctadiene unit, a methylene norbornene unit, an ethylidene norbornene unit, And vinylidene norbornene units. Among these, an ethylidene norbornene unit and / or a vinylidene norbornene unit is preferable because an appropriate crosslinked structure can be given to the ethylene / α-olefin / non-conjugated diene copolymer of the component (B). The non-conjugated diene units listed above may contain only one type or two or more types.

  In the ethylene / α-olefin / non-conjugated diene copolymer of component (B), the content of ethylene units is preferably 30% by weight or more based on the total amount of monomer units constituting component (B). More preferably, it is 40% by weight or more, more preferably 50% by weight or more, and preferably 90% by weight or less, more preferably 80% by weight or less. It is preferable that the content of the ethylene unit is in the above range because moderate flexibility is provided.

  In the ethylene / α-olefin / non-conjugated diene copolymer of component (B), the content of α-olefin units is preferably 10% by weight or more based on the total amount of monomer units constituting component (B). More preferably, it is 20% by weight or more, while it is preferably 50% by weight or less, more preferably 40% by weight or less. It is preferable that the content of the α-olefin unit is in the above range in order to provide appropriate flexibility.

  In the ethylene / α-olefin / non-conjugated diene copolymer of component (B), the content of non-conjugated diene units is preferably 1% by weight relative to the total amount of monomer units constituting component (C). Or more, more preferably 3% by weight or more, while preferably 10% by weight or less, more preferably 8% by weight or less. When the content of the non-conjugated diene unit is not less than the above lower limit value, it is preferable from the viewpoint of increasing the degree of crosslinking of the thermoplastic elastomer composition, and when it is not more than the above upper limit value, it is preferable from the viewpoint of moldability.

  The content of each structural unit of the ethylene / α-olefin / non-conjugated diene copolymer can be determined by infrared spectroscopy.

The Mooney viscosity ML _{1 + 4} (125 ° C.) of the component (B) is 45 or more, preferably 50 or more. The Mooney viscosity ML _{1 + 4} (125 ° C.) of the component (B) is preferably at least the above lower limit from the viewpoint of good compression set.

  As a method for producing the component (B) ethylene / α-olefin / non-conjugated diene copolymer, a known polymerization method using a known catalyst for olefin polymerization is used. For example, a slurry polymerization method, a solution polymerization method, a bulk polymerization method, a gas phase polymerization method and the like using a complex catalyst such as a Ziegler-Natta catalyst, a metallocene complex, or a nonmetallocene complex may be used.

  As the component (B), an ethylene / α-olefin / non-conjugated diene copolymer may be a commercially available product. For example, JSR EPR manufactured by JSR, Mitsui EPT manufactured by Mitsui Chemicals, Esprene (registered trademark) manufactured by Sumitomo Chemical Co., Keltan (registered trademark) manufactured by LANXESS, Nordel (registered trademark) manufactured by Dow, and Vistalon (registered trademark) manufactured by ExxonMobil ) Etc., the corresponding product can be selected and used.

  As a component (B), only 1 type may be used and you may use together 2 or more types of what differs in the kind of alpha olefin and a nonconjugated diene, content of these monomer units, a physical property, etc.

[Content Ratio of Component (A) and Component (B)]
The thermoplastic elastomer composition of the present invention is composed of 1 part by mass or more and less than 50 parts by mass of component (A) and 50 parts by mass of component (B) in a total of 100 parts by mass of component (A) and component (B). It is preferable to contain more than 90 parts by mass, and when the content of component (A) is not less than the above lower limit and the content of component (B) is not more than the above upper limit, the long chain branched structure of component (A) The effect of improving the compression set by using a propylene-based polymer having the above can be obtained more effectively, the content of the component (A) is less than the above upper limit, and the content of the component (B) is more than the above lower limit. And improvement effects, such as a compression set improvement and a softness | flexibility improvement by using a component (B), can fully be acquired. A more preferable content rate is 5 to 48 parts by mass of component (A) and 52 to 95 parts by mass of component (B) in a total of 100 parts by mass of component (A) and component (B), more preferably component. (A) is 15 to 45 parts by mass, and component (B) is 55 to 85 parts by mass.

[Hydrocarbon softener (C)]
Examples of the hydrocarbon rubber softener (C) (may be referred to as “component (C)” in the present invention) include mineral oil softeners, synthetic resin softeners, and the like. From the viewpoint of affinity with mineral oil-based softeners are preferred. Mineral oil softeners are generally a mixture of aromatic hydrocarbons, naphthenic hydrocarbons and paraffinic hydrocarbons, with paraffinic oils in which 50% or more of all carbon atoms are paraffinic hydrocarbons, Those in which 30 to 45% of all carbon atoms are naphthenic hydrocarbons are called naphthenic oils, and those in which 35% or more of all carbon atoms are aromatic hydrocarbons are called aromatic oils. Among these, it is preferable to use paraffinic oil for the thermoplastic elastomer composition of the present invention. In addition, the hydrocarbon-based rubber softener of component (C) may be used alone or in combination of two or more.

  The kinematic viscosity at 40 ° C. of the softener for hydrocarbon rubber is preferably 20 centistokes or more, more preferably 50 centistokes or more, and on the other hand, it is preferably 800 centistokes or less. Preferably it is 600 centistokes or less. In addition, the flash point (COC method) of the hydrocarbon rubber softener is preferably 200 ° C. or higher, and more preferably 250 ° C. or higher.

  Component (C), a hydrocarbon rubber softener, can be obtained as a commercial product. Examples of applicable commercial products include Nisshi Polybutene (registered trademark) HV series manufactured by JX Nippon Oil & Energy Corporation, and Diana (registered trademark) process oil PW series manufactured by Idemitsu Kosan Co., Ltd. Can be appropriately selected and used.

  The thermoplastic elastomer composition of the present invention contains 20 parts by mass or more of the hydrocarbon-based rubber softener of component (C) with respect to 100 parts by mass in total of component (A) and component (B). It is preferable for obtaining a sufficient torque neck improvement effect by component (C). The content of the component (C) is more preferably 30 parts by mass or more, and further preferably 40 parts by mass or more with respect to a total of 100 parts by mass of the component (A) and the component (B). In addition, it is preferable to contain 300 parts by mass or less of the hydrocarbon-based rubber softener of component (C) with respect to 100 parts by mass in total of component (A) and component (B) in order to improve fogging performance. . If the content of the component (C) is at least the above lower limit, the appearance of the molded product and moldability tend to be good, and if the content of the component (C) is below the above upper limit, the heat resistance tends to be good. is there.

[Crosslinking agent (D)]
The thermoplastic elastomer composition of the present invention preferably further contains a cross-linking agent (D) (in the present invention, sometimes referred to as “component (D)”). As described later, the thermoplastic elastomer of the present invention. By performing dynamic heat treatment of the elastomer composition in the presence of the crosslinking agent (D), at least a part of the component (B) is crosslinked, so that the thermoplastic elastomer composition of the present invention has rubber elasticity. It will be good.

  Examples of the crosslinking agent include organic peroxides, phenol resins, and other crosslinking agents (including crosslinking aids). These crosslinking agents can be used alone or in combination of two or more.

  As the organic peroxide that can be used as the cross-linking agent, any of aromatic organic peroxides and aliphatic organic peroxides can be used. Specifically, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl -2,5-di (t-butylperoxy) hexyne-3, 1,3-bis (t-butylperoxyisopropyl) benzene, 1,1-di (t-butylperoxy) -3,3,5 -Dialkyl peroxides such as trimethylcyclohexane; t-butylperoxybenzoate, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2 Peroxyesters such as, 5-di (benzoylperoxy) hexyne-3; acetyl peroxide, lauroyl peroxide, benzoy Peroxide, p- chlorobenzoyl peroxide, hydroperoxide, and the like, such as 2,4-dichlorobenzoyl peroxide and the like. Among these, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane is preferable. These organic peroxides may be used alone or in combination of two or more.

  Examples of the phenol resin that can be used as a crosslinking agent include alkylphenol formaldehyde, bromated alkylphenolanol formaldehyde, and the like. These phenol resins may be used alone or in combination of two or more.

Examples of crosslinking aids other than organic peroxides and phenolic resins include, for example, peroxide aids such as sulfur, p-quinonedioxime, p-dinitrosobenzene, 1,3-diphenylguanidine; stannous chloride・ Cross-linking assistants for phenolic resins such as anhydride, stannous chloride / dihydrate, ferric chloride; polyfunctional vinyl compounds such as divinylbenzene, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate; ethylene Examples thereof include polyfunctional (meth) acrylate compounds such as glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and allyl (meth) acrylate. These may be used alone or in combination of two or more.
For example, phenolic resin cross-linking agents are usually used with activators. Examples of activators that can be used here include stannous chloride, ferric chloride, chlorinated paraffin, chlorinated polyethylene, halogen donors such as chlorosulfonated polyethylene, and iron oxide, titanium oxide, Acid acceptors such as magnesium oxide, silicon dioxide, and zinc oxide are used. When the phenolic resin is halogenated, a halogen donor may not be used.

  In the thermoplastic elastomer composition of the present invention, the amount of the crosslinking agent (including the crosslinking aid) is sufficient for the crosslinking reaction with respect to a total of 100 parts by mass of the component (A), the component (B) and the component (C). From the viewpoint of proceeding to the above, it is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and further preferably 0.3 parts by mass or more. On the other hand, the use amount of the crosslinking agent is preferably 10 parts by mass or less, more preferably from the viewpoint of controlling the crosslinking reaction with respect to the total of 100 parts by mass of the component (A), component (B) and component (C). Is 8 parts by mass or less, more preferably 6 parts by mass or less, and particularly preferably 4 parts by mass or less.

[Other ingredients]
In the thermoplastic elastomer composition of the present invention, in addition to the components (A) to (D), other components can be blended as necessary within a range not impairing the effects of the present invention.

  Examples of other components include resins such as thermoplastic resins and elastomers other than components (A) and (B), antioxidants, fillers, heat stabilizers, light stabilizers, ultraviolet absorbers, neutralizers, Lubricant, anti-fogging agent, anti-blocking agent, slip agent, dispersant, colorant, flame retardant, antistatic agent, conductivity-imparting agent, metal deactivator, molecular weight regulator, antibacterial agent, antifungal material, fluorescence Examples thereof include various additives such as a brightener. Any of these may be used alone or in combination.

  Examples of thermoplastic resins other than components (A) and (B) include polyphenylene ether resins; polyamide resins such as nylon 6 and nylon 66; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyoxymethylene homo Examples thereof include polyoxymethylene resins such as polymers and polyoxymethylene copolymers; polymethyl methacrylate resins and polyolefin resins (excluding those corresponding to component (A) or component (B)). Examples of elastomers other than components (A) and (B) include styrene elastomers; polyester elastomers; polybutadiene and the like.

  Examples of the antioxidant include phenolic antioxidants, phosphite antioxidants, thioether antioxidants, and the like. When using antioxidant, it is normally used in 0.01-3.0 mass parts with respect to a total of 100 mass parts of a component (A), a component (B), and a component (C).

  Examples of the filler include glass fiber, hollow glass sphere, carbon fiber, talc, calcium carbonate, mica, potassium titanate fiber, silica, metal soap, titanium dioxide, and carbon black. When using a filler, it is normally used in 0.1-50 mass parts with respect to a total of 100 mass parts of a component (A), a component (B), and a component (C).

[Method for producing thermoplastic elastomer composition]
As described above, the thermoplastic elastomer composition of the present invention is preferably a composition containing a predetermined amount of the component (A), the component (B) and the component (C), and other components used as necessary. It is produced by dynamic heat treatment in the presence of a crosslinking agent (D).

  In the present invention, “dynamic heat treatment” means kneading in a molten or semi-molten state in the presence of a crosslinking agent. This dynamic heat treatment is preferably carried out by melt kneading. As a mixing and kneading apparatus therefor, for example, a non-open Banbury mixer, a mixing roll, a kneader, a twin screw extruder, or the like is used. Among these, it is preferable to use a twin screw extruder. As a preferable aspect of the manufacturing method using this twin-screw extruder, each component is supplied to the raw material supply port (hopper) of the twin-screw extruder which has a some raw material supply port, and dynamic heat processing is performed.

  The temperature at which the dynamic heat treatment is performed is usually 80 to 300 ° C, preferably 100 to 250 ° C. Moreover, the time which performs dynamic heat processing is 0.1 to 30 minutes normally.

In the case of producing the thermoplastic elastomer composition of the present invention by performing dynamic heat treatment with a twin-screw extruder, the barrel radius (R (mm)) of the twin-screw extruder and the screw rotation speed (N (rpm)) And the discharge amount (Q (kg / hour)) is preferably extruded while maintaining the relationship of the following formula (1), more preferably extruded while maintaining the relationship of the following formula (2).
2.6 <NQ / R3 <22.6 (1)
3.0 <NQ / R3 <20.0 (2)

  It is thermoplastic that the relationship among the barrel radius (R (mm)), screw rotation speed (N (rpm)) and discharge rate (Q (kg / hour)) of the twin screw extruder is larger than the lower limit value. It is preferable for efficiently producing an elastomer composition. On the other hand, it is preferable that the relationship is smaller than the above upper limit value because it suppresses heat generation due to shearing and makes it difficult for foreign matters that cause poor appearance to occur.

  In the raw material supply method, it is more preferable that a part of the component (A) is introduced from a supply port in the middle of the extruder from the viewpoint of improvement in tensile strength and compression set. The amount of the component (A) introduced from the supply port in the middle is preferably 70% or less of the total amount of the component (A) for improving tensile strength and heat resistance, and 55% of the total amount of the component (A). The following is more preferable. Further, the amount of the component (A) introduced from the supply port in the middle is preferably 10% or more of the total amount of the component (A) for improving compression set, and 20% of the total amount of the component (A). The above is more preferable.

  In the production of the thermoplastic elastomer composition of the present invention, the ethylene / α-olefin / non-conjugated diene copolymer of component (B) is replaced with at least part of the hydrocarbon-based rubber softener of component (C). The component (B) can also be used as an oil-extended ethylene / α-olefin / non-conjugated diene copolymer after treatment.

  As a method (oil-extended method) for producing an oil-extended ethylene / α-olefin / non-conjugated diene copolymer with the component (B) and the component (C), a known method can be used. As the oil spreading method, for example, using a mixing roll or a Banbury mixer, an ethylene / α-olefin / non-conjugated diene copolymer and a hydrocarbon rubber softener are mechanically kneaded and oil-extended. A method of adding a predetermined amount of a mineral oil rubber softener to an α-olefin / non-conjugated diene copolymer and then removing the solvent by a method such as steam stripping, crumb-like ethylene / α-olefin / non-conjugated diene Examples thereof include a method of stirring and impregnating a mixture of a copolymer and a mineral oil-based rubber softener with a Henschel mixer or the like.

  Such an oil-extended ethylene / α-olefin / non-conjugated diene copolymer can be obtained as a commercial product. For example, a corresponding product can be selected and used from JSR EPR manufactured by JSR, Mitsui EPT manufactured by Mitsui Chemicals, Espren (registered trademark) manufactured by Sumitomo Chemical, Keltan (registered trademark) manufactured by LANXESS, and the like.

[Physical properties of thermoplastic elastomer composition]
The thermoplastic elastomer composition of the present invention has a melt flow rate (MFR) (230 ° C., 49 N) measured at a measurement temperature of 230 ° C. and a measurement load of 49 N by a method based on JIS K7210 standard of 0.01 g / 10 min or more. From the viewpoint of moldability, the MFR (230 ° C., 49N) is more preferably 0.05 g / 10 min or more, and further preferably 0.1 g / 10 min or more. From the viewpoint of moldability, the MFR (230 ° C., 49N) is preferably 100 g / 10 min or less, more preferably 50 g / 10 min or less, and further preferably 20 g / 10 min or less. preferable.

  Moreover, it is preferable that the hardness duro A measured based on JISK6253 (JIS-A) about the molded object formed by shape | molding the thermoplastic elastomer composition of this invention is the range of 35-95, 40- A range of 90 is more preferable.

[Molded products / uses]
The thermoplastic elastomer composition of the present invention can be formed into a molded body by various molding methods such as injection molding, extrusion molding, hollow molding, compression molding, etc., which are usually used for thermoplastic elastomer compositions. Of these, injection molding and extrusion molding are preferred. Moreover, it can also be set as the molded object which performed secondary processing, such as lamination molding and thermoforming, after performing these shaping | molding.

  The thermoplastic elastomer composition of the present invention comprises an automobile part such as a skin, weather strip, ceiling material, interior sheet, cushion, boot, bumper molding, side molding, air spoiler, air duct hose, sealing material; Civil engineering and building materials parts such as window frames and seal materials (gaskets, packing); sports equipment such as golf club grips and tennis racket grips; industrial parts such as hose tubes and gaskets; hoses, packings, etc. Home appliance parts; medical parts such as medical containers, gaskets, and packing; food parts such as containers and packing; medical equipment parts; electric wires; miscellaneous goods and the like.

  EXAMPLES Hereinafter, although the content of this invention is demonstrated more concretely using an Example, this invention is not limited by a following example, unless the summary is exceeded. The values of various production conditions and evaluation results in the following examples have meanings as preferred values of the upper limit or lower limit in the embodiments of the present invention, and the preferred ranges are the upper limit or lower limit values described above, and It may be a range defined by a combination of values of the examples or values between the examples.

[raw materials]
The raw materials used in the following examples and comparative examples are as follows.

<Component (A)>
(A-1): Modified polypropylene / Nippon Polypro Co., Ltd. WAYMAX MFX8
MFR (230 ° C., 21.2 N): 1 g / 10 min Methylene carbon (Ca, Cb, Cc) and methine carbon (Cbr): Observed long chain branching of 0.1 / 1000 total propylene (total skeleton forming carbon) Per 1000)
The branching index g ′ when the absolute molecular weight Mabs is 1 million: 0.89
(A-2): Modified polypropylene / manufactured by Nippon Polypro Co., Ltd. WAYMAX MFX3
MFR (230 ° C., 21.2 N): 8 g / 10 min Methylene carbon (Ca, Cb, Cc) and methine carbon (Cbr): Observed long chain branching amount: 0.2 / 1000 total propylene Absolute molecular weight Mabs is Branch index g 'at 1 million: 0.87

<Component (B)>
(B-1) + (C-1) mixture: oil-extended ethylene / propylene / 5-ethylidene-2-norbornene copolymer (100 parts by mass of component (B-1) and 100 parts by mass of component (C-1)) blend)
(B-1): Ethylene / propylene / 5-ethylidene-2-norbornene copolymer Mooney viscosity ML _{1 + 4} (125 ° C.): 64
Ethylene unit content: 67% by mass
5-ethylidene-2-norbornene unit content: 4.5% by mass
(C-1) Paraffin oil / Diana process oil PW-90 manufactured by Idemitsu Kosan Co., Ltd.
Kinematic viscosity at 40 ° C: 95.54 centistokes Pour point: -15 ° C
Flash point: 272 ° C
(B-2): Ethylene / propylene / 5-ethylidene-2-norbornene copolymer / MITI CHEMICAL CO., LTD. EPT3092PM
Mooney viscosity ML _{1 + 4} (125 ° C.): 61
Ethylene unit content: 65% by mass
5-ethylidene-2-norbornene unit content: 4.6% by mass

[Component (C)]
(C-1): Paraffin oil / Diana process oil PW-90 manufactured by Idemitsu Kosan Co., Ltd.
Kinematic viscosity at 40 ° C: 95.54 centistokes Pour point: -15 ° C
Flash point: 272 ° C

[Component (D)]
(D-1): Mixture of 2,5-dimethyl-2,5-di (t-butylperoxy) hexane 40% by mass and calcium carbonate 60% by mass / Kayahexa AD-40C manufactured by Kayaku Akzo Corporation
(D-2) + (C-1) mixture: phenol resin (component (D-2)) 30 parts by mass and component (C-1) 70 parts by mass (D-2) Both ends are methylol groups. Alkylphenol formaldehyde resin / Takaki roll 201 manufactured by Taoka Chemical Co., Ltd.
(C-1) Paraffin oil / Diana process oil PW-90 manufactured by Idemitsu Kosan Co., Ltd.
Kinematic viscosity at 40 ° C: 95.54 centistokes Pour point: -15 ° C
Flash point: 272 ° C

[Component (E)]
(E-1): Mixture of 55% by mass of divinylbenzene and 45% by mass of ethylvinylbenzene / Divinylbenzene manufactured by Wako Pure Chemical Industries, Ltd.

[Component (F)]
(F-1): Polypropylene / MA3 manufactured by Nippon Polypro Co., Ltd.
MFR (230 ° C., 21.2 N): 11 g / 10 minutes (F-2): Polypropylene / Nippon Polypro Corporation FY6
MFR (230 ° C., 21.2 N): 2.5 g / 10 minutes

[Component (G)]
(G-1): Crosslinking aid / Wako Pure Chemical Industries, Ltd. stannous chloride dihydrate

[Ingredient (H)]
(H-1): Acid acceptor / Zinc oxide manufactured by Wako Pure Chemical Industries, Ltd.

[Component (I)]
(I-1): Filler / Talc PHSH manufactured by Takehara Chemical Co., Ltd.

[Evaluation method]
Evaluation methods of thermoplastic elastomer compositions in the following examples and comparative examples are as follows.
In the following measurements (2) to (4), an injection pressure of 50 MPa and a cylinder temperature of 220 ° C. are used with an in-line screw type injection molding machine (“IS130” manufactured by Toshiba Machine Co., Ltd.) using each thermoplastic elastomer composition. , And injection-molded into a sheet having a thickness of 2 mm, a width of 120 mm, and a length of 80 mm at a mold temperature of 40 ° C. The sheet (thickness of 2 mm × width of 120 mm × length of 80 mm) was measured for the tensile test in (3) After molding, a test piece conforming to JIS K6251 (JIS-3 dumbbell) was punched out and used.
For the measurement of compression set of (4), after forming the sheet (thickness 2 mm × width 120 mm × length 80 mm), JIS K6262 compliant (Type A disk: 29 mmφ) punched out test pieces are used in six layers. did.
In the measurement of the surface roughness in (5), a 40 mm diameter single screw extruder (L / D = 22, compression ratio = 2.77, full flight screw) manufactured by Mitsubishi Heavy Industries Ltd., a sheet shape having a width of 25 mm and a thickness of 1 mm. , Under the hopper: 170 ° C., cylinder: 180 ° C. to 200 ° C., die: 200 ° C., molding under the conditions of screw rotation: 30 rpm, and measurement using the obtained sheet did.

(1) Melt flow rate (MFR)
Measurement was performed at a measurement temperature of 230 ° C. and a measurement load of 49 N by a method based on the standard of JIS K7210.

(2) Duro hardness A
Hardness (after 15 seconds) was measured by a method based on JIS K6253 (JIS-A).

(3) Tensile strength at cutting / elongation at cutting (tensile test)
It was measured at a test speed of 500 mm / min by a method based on the standard of JIS K6251.

(4) Compression set The measurement was performed at 70 ° C. for 22 hours under 25% compression conditions by a method based on the standard of JIS K6262.

(5) Surface roughness The arithmetic average roughness was measured based on the standard of JIS B0601 (2001).

[Example / Comparative Example]
<Example 1>
Part (15.5 parts by mass) of component (A-1), 46 parts by mass of component (B-1) + (C-1), 46 parts by mass of component (B-2), component (D-1) 0.62 parts by mass, 0.46 parts by mass of component (E-1), 0.15 parts by mass of Irganox (registered trademark / manufactured by BASF Japan Ltd.) 1010 as an antioxidant, and black pigment (carbon concentration 40 masses) % Mass) and 3 parts by mass were blended with a Henschel mixer for 1 minute. The mixture was fed into the supply port upstream of the same-direction twin-screw extruder (Nippon Steel Works “TEX30”, L / D = 46, number of cylinder blocks: 12) with a weight feeder. The remaining component (A-1) 15.5 parts by mass (50% by mass of the amount of component (A-1) added) was charged from the supply port in the middle of the extruder, and then the component (C- 1) 31 parts by mass are supplied from a supply port in the middle of the extruder, and the temperature is raised in the range from 120 to 180 ° C. from the upstream part to the downstream part at a discharge rate of 20 kg / h, and pelletized. Thus, a thermoplastic elastomer composition was produced. About the obtained thermoplastic elastomer composition, evaluation of said (1)-(4) was implemented. The obtained evaluation results are shown in Table-1.

<Example 2 and Comparative Examples 1-2>
Except having changed the compounding composition as shown in Table 1, it implemented like Example 1 and obtained the pellet of the thermoplastic elastomer composition. Evaluation similar to Example 1 was implemented about the obtained thermoplastic elastomer composition. The obtained evaluation results are shown in Table-1.

<Example 3>
Component (A-1) 37 parts by mass, Component (B-1) + (C-1) 126 parts by mass, Component (G-1) 1.3 parts by mass, Component (H-1) 0.65 parts by mass 2.6 parts by mass of component (I-1), 0.16 parts by mass of Irganox (registered trademark / manufactured by BASF Japan Ltd.) 1010 as an antioxidant, irgastab (registered trademark / manufactured by BASF Japan KK) FS301FF 0.16 part by mass was blended with a Henschel mixer for 1 minute. The mixture was fed into the supply port upstream of the same-direction twin-screw extruder (Nippon Steel Works “TEX30”, L / D = 52.5, number of cylinder blocks: 14) with a weight feeder. The remaining component (D-2) + (C-1) mixture 8.1 parts by mass and (C-1) 10.6 parts by mass were respectively supplied from the supply port in the middle of the extruder with a liquid pump, and the total At a discharge rate of 20 kg / h, the temperature from the upstream portion to the downstream portion was raised in the range of 150 to 200 ° C., melted and kneaded, and pelletized to produce a thermoplastic elastomer composition. About the obtained thermoplastic elastomer composition, evaluation of said (1)-(5) was implemented. The obtained evaluation results are shown in Table-2.

<Example 4 and Comparative Example 3>
Except having changed the compounding composition as shown in Table-2, it implemented similarly to Example 3 and obtained the pellet of the thermoplastic elastomer composition. Evaluation similar to Example 3 was implemented about the obtained thermoplastic elastomer composition. The obtained evaluation results are shown in Table-2.

[Discussion]
As shown in Tables 1 and 2, it can be seen that Examples 1 to 4 corresponding to the thermoplastic elastomer composition of the present invention all have good compression set characteristics. Moreover, it turns out that all of Examples 3 and 4 have high surface roughness.
On the other hand, Comparative Examples 1 to 3 do not use the component (A) of the present invention, but instead use the component (F), but Comparative Examples 1 and 2 have insufficient compression set characteristics, Comparative Example 3 had a low surface roughness.

  The thermoplastic elastomer composition of the present invention is excellent in compression set and can improve the surface roughness value of the molded product and contribute to the uniformity and design of the molded product surface. It is useful in automobile fields such as boots and skins; architectural fields such as gaskets and packings; miscellaneous goods fields such as grips and casters.

Claims (9)

Propylene polymer (A) having a long chain branched structure, ethylene / α-olefin / non-conjugated diene copolymer (B) having a Mooney viscosity ML _{1 + 4} (125 ° C.) of 45 or more, and a hydrocarbon rubber softener ( A thermoplastic elastomer composition comprising C), wherein the propylene polymer (A) satisfies the following requirement (A-1).
(A-1) In ¹³ C-NMR analysis, methylene carbon (Ca, Cb, Cc) was observed at 44.0-44.1 ppm, 44.7-44.8 ppm, and 44.8-44.9 ppm, respectively. Methine carbon (Cbr) is observed at 31.6-31.7 ppm.   In a total of 100 parts by mass of the propylene-based polymer (A) having a long-chain branched structure and the ethylene / α-olefin / non-conjugated diene copolymer (B), a propylene-based polymer (A ) In an amount of 1 part by mass to less than 50 parts by mass, a propylene-based polymer having a long chain branched structure (A) containing more than 50 parts by mass of ethylene / α-olefin / non-conjugated diene copolymer (B) (A). ) And ethylene / α-olefin / non-conjugated diene copolymer (B) in a total of 100 parts by mass, the thermoplastic rubber softener (C) is contained in an amount of 20 parts by mass or more. Elastomer composition   The thermoplastic elastomer composition according to claim 1 or 2, wherein the propylene-based polymer (A) has a branching index g 'in the range of 0.75 or more and 0.95 or less when the absolute molecular weight Mabs is 1,000,000.   The crosslinking agent (D) is contained in an amount of 0.1 to 10 parts by mass with respect to 100 parts by mass of the ethylene / α-olefin / non-conjugated diene copolymer (B). The thermoplastic elastomer composition described in 1.   The thermoplastic elastomer composition according to claim 4, wherein the crosslinking agent (D) is an organic peroxide and / or a phenol resin.   Ethylene / propylene / ethylidene norbornene and / or vinylidene norbornene in which ethylene / α-olefin / nonconjugated diene copolymer (B) has an ethylene unit content of 30 to 90% by mass and a nonconjugated diene unit content of 1 to 10% by mass The thermoplastic elastomer composition according to any one of claims 1 to 4, which is a copolymer.   The thermoplastic elastomer composition according to any one of claims 1 to 6, wherein the hydrocarbon rubber softener (C) is a paraffin oil having a kinematic viscosity at 40 ° C of 20 to 800 centistokes.   The thermoplastic elastomer composition according to any one of claims 1 to 7, which is a composition for a non-foamed molded article.   The molded object formed by shape | molding the thermoplastic elastomer composition of any one of Claim 1 to 8.