JP6238607B2 - Foamed thermoplastic elastomer composition for composite molding and molded article thereof - Google Patents

Description

The present invention relates to a polyolefin-based thermoplastic elastomer composition, and in particular, a foamed thermoplastic elastomer for composite molding with polypropylene, which is excellent in expansion ratio, composite moldability with polypropylene (heat-fusibility), injection moldability, and extrusion moldability. Relates to the composition.

In recent years, thermoplastic elastomers, which are soft materials with rubber elasticity, do not require a vulcanization process, and have thermoplastic processability and recyclability similar to those of thermoplastic resins, such as automotive parts, home appliance parts, wire coating materials, medical Widely used in fields such as parts, footwear and sundries.

Among thermoplastic elastomers, polyolefins in which ethylene / propylene / non-conjugated diene (for example, ethylidene norbornene) copolymer rubber synthesized with a multisite catalyst, polypropylene, and a component containing paraffin oil are crosslinked with a phenol resin crosslinking agent. Thermoplastic elastomers are rich in flexibility, have good rubber elasticity at room temperature, and the thermoplastic elastomer compositions obtained from these are excellent in processability, and are widely used as substitutes for vulcanized rubber. Yes.

However, when these polyolefin-based elastomers are foamed by adding a foaming agent, they have significant problems in terms of expansion ratio, composite moldability with polypropylene (heat-fusibility), injection moldability, and extrusion moldability. For this reason, the use of thermally expanded microcapsules as a foaming agent has been studied (for example, Patent Document 1), but is expensive and unsuitable for recycling. The wearability was not satisfactory.

Japanese Patent Laid-Open No. 11-343362

An object of the present invention is to provide a foamed thermoplastic elastomer composition for composite molding with polypropylene having excellent expansion ratio, composite moldability with polypropylene (heat-fusibility), injection moldability, and extrusion moldability. .

That is, according to the first invention of the present invention, (a) 100 parts by mass of ethylene / α-olefin / non-conjugated polyene copolymer rubber polymerized using a metallocene catalyst,
(B) 20 to 350 parts by mass of a polypropylene resin,
(C) 2 to 25 parts by mass of an alkylphenol formaldehyde resin crosslinking agent,
(H) 0.05 to 30 parts by mass of an acrylic-modified polytetrafluoroethylene polymer, and (i) 0.01 to 10 parts by mass of a foaming agent other than the thermal expansion microcapsule,
A foamed thermoplastic elastomer composition for composite molding with polypropylene is provided.

According to a second invention of the present invention, the thermoplastic elastomer composition according to the first invention, which has been once molded, contains 5 to 50% by mass as recycled, and the polypropylene according to the first invention, A foamed thermoplastic elastomer composition for composite molding is provided.

According to a third aspect of the present invention, there is provided a composite molded article formed from the foamed thermoplastic elastomer composition according to the first aspect or the second aspect and polypropylene.

The thermoplastic elastomer composition of the present invention is excellent in foaming ratio, composite moldability with polypropylene (heat-fusibility), injection moldability, and extrusion moldability, so it can be used for automobile interior materials (sheet skins, pillars, weather strips, etc.) ) And exterior materials (mall, trim, etc.), industrial parts (pipes, tubes, wire covering materials, etc.), furniture (chair seats, armrests, etc.), miscellaneous goods (shoes, slippers, etc.) It can be used suitably.

Hereinafter, components of the thermoplastic elastomer composition of the present invention, a method for producing the thermoplastic elastomer composition, and uses of the thermoplastic elastomer composition will be described in detail.

1. Components of the foamed thermoplastic elastomer composition Component (a): (Essential component)
Component (a) of the present invention is an ethylene / α-olefin / non-conjugated polyene copolymer rubber polymerized using a metallocene catalyst.

The metallocene catalyst is a single site catalyst or a semi-multisite catalyst and is distinguished from a multisite catalyst such as a Ziegler catalyst. Metallocene catalysts are known per se, and are highly active polymerization catalysts composed of a cyclopentadienyl derivative of a transition metal such as titanium or zirconium and a cocatalyst.

The ethylene / α-olefin / nonconjugated polyene copolymer rubber is obtained by polymerizing ethylene, an α-olefin having 3 to 20 carbon atoms such as propylene, 1-butene, 1-pentene and the like and a nonconjugated polyene compound. It is a copolymer.

As the non-conjugated polyene, a non-conjugated diene is preferable. Examples of non-conjugated dienes include 5-ethylidene-2-norbornene (ENB), 1,4-hexadiene, 5-methylene-2-norbornene (MNB), 1,6-octadiene, 5-methyl-1,4- Hexadiene, 3,7-dimethyl-1,6-octadiene, 1,3-cyclopentadiene, 1,4-cyclohexadiene, tetrahydroindene, methyltetrahydroindene, dicyclopentadiene, 5-isopropylidene-2-norbornene, 5- Examples include vinyl-norbornene, dicyclooctadiene, and methylene norbornene. Of these, 5-ethylidene-2-norbornene (ENB) is preferred from the viewpoint of heat-fusibility with polypropylene.

Specific examples of the component (a) include, for example, ethylene / propylene / nonconjugated diene copolymer rubber, ethylene / 1-butene / nonconjugated diene copolymer rubber, and the like. Among these, ethylene / propylene / non-conjugated diene copolymer rubber (EPDM) is preferable from the viewpoint of composite moldability with polypropylene (heat-fusibility).

The ethylene / α-olefin / non-conjugated polyene copolymer rubber polymerized using a metallocene catalyst is
Compared to ethylene / α-olefin / non-conjugated polyene copolymer rubber polymerized using a multi-site catalyst such as a Ziegler-based catalyst, the molecular weight distribution and composition distribution are very narrow.

Therefore, by using ethylene / α-olefin / non-conjugated polyene copolymer rubber polymerized with a metallocene catalyst as component (a), the ethylene / α-olefin / non-conjugated polyene copolymer polymerized with a multi-site catalyst is used. Rather than using polymer rubber, the heat-fusibility in composite molding with polypropylene can be greatly improved.

40-80 mass% is preferable, and, as for the range of ethylene content of a component (a), More preferably, it is 40-75 mass%. Within the above range, the heat fusion property in the composite molding with polypropylene is excellent, and the foamability and the moldability are also excellent, which is very preferable. Moreover, 0.5-8 mass% is preferable, and, as for nonconjugated polyene content, More preferably, it is 3-8 mass%. In the said range, it is excellent in the heat sealing | fusion property in composite molding with a polypropylene.

Moreover, 10-180 are preferable and, as for the Mooney viscosity ML1 _{+ 4} (125 degreeC) of a component (a), More preferably, it is 20-150. When the Mooney viscosity ML _{1 + 4} (125 ° C.) of the component (a) is in the above range, the thermoplastic elastomer composition is excellent in heat fusion in composite molding with polypropylene, and foamability and moldability are also good.

Examples of commercially available products that can be used as component (a) include Nordel manufactured by DuPont Dow Elastomer Japan.
IP 4760P, 4725P and 4770R (trade names).

Ingredient (b): (essential ingredient)
Component (b) of the present invention is a polypropylene resin, and has the effects of improving oil resistance, adjusting hardness, and improving moldability.

Examples of the polypropylene resin used as component (b) include propylene homopolymers; propylene and other small amounts of α-olefins such as ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene and the like. Copolymer (block copolymer, random copolymer); and the like. Among these, the thing whose melting | fusing point (Tm) measured with the differential scanning calorimeter (DSC) is 150-167 degreeC is preferable. A melt mass flow rate (MFR) “ASTM-D-1238, L condition, 230 ° C.” of 0.1 to 10 g / 10 min is preferable.

The compounding quantity of a component (b) is 20-350 mass parts with respect to 100 mass parts of components (a) at the point of the heat-fusion property in composite molding with a polypropylene. Preferably it is 20-220 mass parts. If the blending amount of component (b) exceeds the above upper limit value, the heat-fusibility in the composite molding with polypropylene is inferior, and the extrusion moldability and the injection moldability deteriorate. It is inferior in wearability, and extrusion moldability and injection moldability are lowered.

Component (c): (Essential component)
Component (c) of the present invention is a phenol resin-based crosslinking agent.

Preferred phenolic resin crosslinkers, called resole resins, are prepared by condensation of alkyl-substituted phenols or unsubstituted phenols with aldehydes in alkaline media, preferably with formaldehyde, or condensation of bifunctional phenol dialcohols. Is done. Alkyl substituents of alkyl substituted phenols typically have from 1 to about 10 carbon atoms. Preferred are dimethylolphenols or phenolic resins substituted with an alkyl group having from 1 to about 10 carbon atoms in the p-position. These phenolic crosslinking agents are typically thermosetting resins and are referred to as phenolic resin crosslinking agents or phenolic resins. Specific examples of the crosslinking of thermoplastic vulcanizates with phenolic resins are described in U.S. Pat. No. 4,311,628, U.S. Pat. Nos. 2,972,600 and 3,287,440. Techniques can also be used in the present invention.

Preferred phenolic resin crosslinking agents include, for example, general formula (I),

(Wherein Q is a divalent group selected from the group consisting of —CH ₂ — and —CH ₂ —O—CH ₂ —, m is a natural number of 0 or 1-20, and R ′ is an organic group. Is)

Can be defined by
Q is preferably a divalent group —CH ₂ —.
m is preferably a natural number of 0 or 1 to 10, more preferably a natural number of 0 or 1 to 5.
The number of carbon atoms of R ′ is preferably a natural number of 1-20, more preferably a natural number of 4-12. The organic group is preferably an alkyl group.

Among the phenol resins, alkylphenol formaldehyde resins and methylolated alkylphenol resins are preferable. Also preferred are brominated phenolic resins in which the terminal hydroxyl groups are brominated, such as brominated alkylphenol resins. In particular, an alkylphenol formaldehyde resin is preferable.

Examples of commercially available products of the above-mentioned phenolic cross-linking agents include tackolol 201 (alkylphenol formaldehyde resin, manufactured by Taoka Chemical Co., Ltd.), tackolol 250-I (brominated alkylphenol formaldehyde resin having a bromination rate of 4%, Taoka Chemical Industries, Ltd.) Manufactured), tackolol 250-III (brominated alkylphenol formaldehyde resin, manufactured by Taoka Chemical Industry Co., Ltd.), PR-4507 (manufactured by Gunei Chemical Industrial Co., Ltd.), Vulkaresat 510E (manufactured by Hoechst), Vulkaresat 532E (manufactured by Hoechst), Vulcaresen E ( Hoechst), Vulkaresen 105E (Hoechst), Vulcaren 130E (Hoechst), Vulcaresol 315E (Hoechst) ), Amberol ST 137X (Rohm & Haas), Sumilite Resin PR-22193 (Sumitomo Durez), Symform-C-100 (Anchor Chem.), Symform-C-1001 (Anchor Chem.) , Tamorol 531 (manufactured by Arakawa Chemical Co., Ltd.), Schenectady SP1059 (manufactured by Schenectady Chem.), Schenectady SP1045 (manufactured by Schematy Chem.), CRR-0803 (manufactured by U.C.C.), Schenectady SP1055 Schemy Chem Manufactured), Spectady SP1056 (manufactured by Spectady Chem.), CRM-0803 (manufactured by Showa Union Synthesis Co., Ltd.) Vulkadur A (Bayer Corporation) and the like, can be preferably used Tackirol 201 (alkylphenol formaldehyde resin) among them.

The compounding amount of the component (c) is 2 to 25 parts by mass with respect to 100 parts by mass of the component (a) in terms of heat-fusibility in composite molding with polypropylene. Preferably it is 5-25 mass parts. When the blending amount of the component (c) exceeds the upper limit, the heat-fusibility in the composite molding with polypropylene is inferior, the fluidity of the thermoplastic elastomer composition is remarkably reduced, and the production / molding becomes difficult. On the other hand, if it is less than the lower limit, the heat-fusibility in the composite molding with polypropylene is inferior, and the injection moldability and extrusion moldability deteriorate.

Component (e): Cross-linking accelerator (optional component)
Component (e) is an optional component and is used to more effectively improve the function of the crosslinking agent of component (c). As the component (e), for example, zinc oxide, magnesium oxide, stannous chloride and the like can be used. In addition, when using zinc oxide as a crosslinking catalyst, a stearic acid metal salt etc. can be used together as a dispersing agent. As component (e), zinc oxide is particularly preferred.

A component (e) is mix | blended with the quantity of 20 mass parts or less with respect to 100 mass parts of components (a) as needed. In particular, when the component (e) is zinc oxide, 0.05 to 20 parts by mass is preferable with respect to 100 parts by mass of the component (a), and when the component (e) is stannous chloride, the component ( a) 0.1-10 mass parts is preferable with respect to 100 mass parts.

In the present invention, it is preferable to combine the component (c) phenol resin and the stannous chloride as the component (e), since the heat-fusibility with polypropylene can be further improved. Moreover, when zinc oxide and stannous chloride are used in combination, heat fusion, injection moldability, and extrusion moldability in composite molding with polypropylene are improved, which is more preferable.

Component (f): Non-aromatic rubber softener (optional component)
Component (f) is an optional component and is used for the purpose of imparting flexibility and improving moldability of the thermoplastic elastomer composition.

Examples of the non-aromatic rubber softener that can be used as the component (f) include paraffinic compounds having 4 to 155 carbon atoms, preferably paraffinic compounds having 4 to 50 carbon atoms. Is butane, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, nonadecane, eicosan, heneicosan, docosan, tricosan, tetracosan, pentacosan, hexacosan, heptacosan, octacosan, N-paraffins (linear saturated hydrocarbons) such as nonacosan, triacontane, hentriacontane, dotriacontane, pentatriacontane, hexacontane and heptacontane; isobutane, isopentane, neopentane Isohexane, isopentane, neohexane, 2,3-dimethylbutane, 2-methylhexane, 3-methylhexane, 3-ethylpentane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane, 2,2,3-trimethylbutane, 3-methylheptane, 2,2-dimethylhexane, 2,3-dimethylhexane, 2,4-dimethylhexane, 2,5-dimethylhexane, 3 , 4-dimethylhexane, 2,2,3-trimethylpentane, isooctane, 2,3,4-trimethylpentane, 2,3,3-trimethylpentane, 2,3,4-trimethylpentane, isononane, 2-methylnonane, Isodecane, Isoundecane, Isododecane, Isotridecane, Isotetradecane, Isope Tadekan, iso-octadecane, Isonanodekan, isoeicosane, isoparaffins such as 4-ethyl-5-methyl-octanoic (branched saturated hydrocarbons); and, may be mentioned derivatives of these saturated hydrocarbons. As the component (f), one or a mixture of two or more of these can be used. Moreover, what is liquid at room temperature is preferable.

Commercially available non-aromatic rubber softeners that are liquid at room temperature include NA Solvent (isoparaffinic hydrocarbon oil) manufactured by Nippon Oil & Fats Co., Ltd., and PW-90 (n-paraffinic process manufactured by Idemitsu Kosan Co., Ltd.). Oil), IP-solvent 2835 (synthetic isoparaffinic hydrocarbon, 99.8 wt% or more isoparaffin) manufactured by Idemitsu Petrochemical Co., Ltd., neothiozole (n-paraffinic process oil) manufactured by Sanko Chemical Co., Ltd., and the like. .

Moreover, a small amount of unsaturated hydrocarbons and derivatives thereof may coexist in the non-aromatic rubber softener used as component (f). Unsaturated hydrocarbons include ethylene, propylene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene, 3-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2 -Ethylene hydrocarbons such as butene, 1-hexene, 2,3-dimethyl-2-butene, 1-heptene, 1-octene, 1-nonene, 1-decene; acetylene, methylacetylene, 1-butyne, 2- And acetylene hydrocarbons such as butyne, 1-pentyne, 1-hexyne, 1-octyne, 1-nonine and 1-decyne.

The blending amount of the component (f) is preferably 480 parts by mass or less, more preferably 260 parts by mass or less with respect to 100 parts by mass of the component (a) as necessary.

(H) Acrylic modified polytetrafluoroethylene polymer (essential component)
The composition of the present invention contains component (h) acrylic-modified polytetrafluoroethylene (modified polytetrafluoroethylene, hereinafter abbreviated as modified PTFE). The component (h) is preferably a mixture of polytetrafluoroethylene and an alkyl (meth) acrylate having 5 to 30 carbon atoms. This mixture is commercially available, and examples thereof include METABRENE A-3000 (trade name) manufactured by Mitsubishi Rayon Co., Ltd.

The compounding quantity of a component (h) is 0.05-30 mass parts with respect to 100 mass parts of components (a) at the point of heat-fusibility with a polypropylene. Preferably it is 0.5-30 mass parts, More preferably, it is 1-25 mass parts.
If it is less than the lower limit, the foamability, heat-fusibility with polypropylene (composite moldability), extrusion moldability, and injection moldability deteriorate. When the upper limit is exceeded, foamability, heat-fusibility with polypropylene (composite moldability), extrusion moldability, and injection moldability deteriorate.

(I) Foaming agents other than thermal expansion microcapsules (essential components)
The foaming agent other than the thermal expansion microcapsule used as the component (i) of the present invention can be used regardless of whether it is organic or inorganic. Preferred specific examples of such foaming agents include azo compounds such as azodicarboxylic acid amide, nitroso compounds such as N, N′-dinitrosopentamethylenetetramine, carbonates such as sodium bicarbonate and ammonium bicarbonate, citric acid And organic acids such as sodium citrate and oxalic acid, sodium borohydride and the like. A combination of carbonate and organic acid may also be used. When foam molding is performed at a relatively high temperature, compounds such as p, p′-oxybisbenzenesulfonyl semicarbazide, p-toluenesulfonyl semicarbazide, trihydrazinotriazine, and barium azodicarboxylate can also be used. In general, azodicarboxylic acid amide is preferred. Moreover, you may use water as a component (i).

The foamed thermoplastic elastomer composition for composite molding of the present invention may be obtained by melt-kneading component (i) simultaneously with components (a), (b), (c), (h) and other optional components. However, from the viewpoint of heat-fusibility in composite molding with polypropylene, after producing a thermoplastic elastomer composition containing components (a), (b), (c), (h) and other optional components, Furthermore, it is preferable to obtain by adding component (i).

The amount of component (i) is 0.01 to 10 parts by mass with respect to 100 parts by mass of component (a) in terms of heat-fusibility with polypropylene, foamability, extrusion moldability, and injection moldability. . Preferably, it is 0.1-10 mass parts, More preferably, it is 1-8 mass parts. If it is less than the lower limit, foaming does not occur, and heat fusion with polypropylene (composite moldability), extrusion moldability, and injection moldability deteriorate. If the upper limit is exceeded, molding is not possible.

Other ingredients:
The thermoplastic elastomer composition of the present invention further includes a heat stabilizer, an antioxidant, a light stabilizer, an ultraviolet absorber, a crystal nucleating agent, an antiblocking agent, and a sealability improving agent as long as the object of the present invention is not impaired. , Mold release agents such as stearic acid and silicone oil, lubricants such as polyethylene wax, colorants, pigments, inorganic fillers (alumina, talc, calcium carbonate, mica, wollastonite, clay, carbon), flame retardants (hydration) Metal compounds, red phosphorus, ammonium polyphosphate, antimony, silicone) and the like can be blended.

Examples of the antioxidant include 2,6-di-tert-p-butyl-p-cresol, 2,6-di-tert-butylphenol, 2,4-dimethyl-6-tert-butylphenol, 4,4- Examples thereof include phenolic antioxidants such as dihydroxydiphenyl and tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, phosphite antioxidants, thioether antioxidants, and the like. Of these, phenolic antioxidants and phosphite antioxidants are particularly preferred.

2. Production of foamed thermoplastic elastomer composition for composite molding The foamed thermoplastic elastomer composition for composite molding of the present invention comprises the above components (a) to (c), (h), (i) and, if necessary. The other optional components used can be obtained by melting and kneading them simultaneously or in any order. Preferably, from the viewpoint of heat-fusibility in composite molding with polypropylene, components (a), (b), (c), (h) and other optional components are melt-kneaded to produce a thermoplastic elastomer composition. After that, it can be obtained by further adding component (i).

The method of melt kneading is not particularly limited, and generally known methods can be used. For example, a single screw extruder, a twin screw extruder, a roll, a mixer, or various kneaders can be used. For example, the above operation can be continuously performed by using a suitable L / D twin screw extruder, a mixer, a pressure kneader, or the like. Here, the temperature of the melt-kneading is preferably 160 to 240 ° C., and it is preferable to take a kneading time of 5 to 20 minutes in order to sufficiently advance the crosslinking. More preferably, it is 5 to 10 minutes.

The composite molded body of the present invention is formed from a polypropylene layer and the foamed thermoplastic elastomer composition layer of the present invention.

As a method for producing such a composite molded body, a T-die laminate molding method, a co-extrusion molding method, a blow molding method, an insert injection molding method, a two-color injection molding method, a core back injection molding method, a sandwich injection molding method, an injection Various molding methods such as a press molding method can be used. Among the above molding methods, the insert injection molding method is a method in which a core material (polypropylene) is injection molded in advance, and a molded product is inserted into a mold, and then a gap between the molded product and the mold is inserted. The surface layer material (the thermoplastic elastomer composition obtained by melt-kneading the components (a), (b), (c), (h) and other optional components of the present invention) The two-color injection molding method uses two or more injection molding machines to rotate or move the mold after the core material is injection molded. As a result, the mold cavity is replaced, and a gap is formed between the molded product and the mold, and a molding method for injection molding the surface layer material there, and the core back injection molding method are one unit. After the core material is injection molded using the injection molding machine and one mold, the mold To expand the cavity volume, a molding method for injection-molding the surface layer material in the gap between the molded article and the mold.

As injection molding conditions, molding is generally performed at a molding temperature of 100 to 300 ° C., preferably 150 to 280 ° C., and an injection pressure of 50 to 1,000 kg / cm ² , preferably 100 to 800 kg / cm ² .

When water is used as a foaming agent, it is preferable to press-fit water in a state where the thermoplastic elastomer composition is plasticized in extrusion molding.

The composite molded body comprising the foamed thermoplastic elastomer layer and the polypropylene layer of the present invention thus obtained can be used as various industrial parts. Specifically, because it is easy to recycle, automotive interior materials (seat skins, pillars, weather strips, etc.), exterior materials (malls, trims, etc.), industrial parts (pipes, tubes, wire coating materials) Etc.), furniture (chair seats, armrests, etc.), miscellaneous goods (shoes, slippers, etc.), etc.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to this.

1.
Evaluation Method (1) Method for Measuring Foaming Ratio Using a sheet die having a thickness of 2 mm, the foamed thermoplastic elastomer composition was extruded under the condition of a die outlet resin temperature of 220 ° C. to obtain a foamed sheet. Subsequently, the specific gravity (g1) of the foam sheet was determined from the volume and mass of the foam sheet.
Next, from the sheet obtained by extruding the thermoplastic elastomer composition having the same composition as the foamed thermoplastic elastomer composition used for the molding of the foamed sheet, except that the foaming agent is not contained, from the above-mentioned conditions, In the same manner as above, the specific gravity (g2) of the unfoamed sheet was determined.
The expansion ratio (h) was calculated by the following formula.
h = g2 / g1

(2) Extrudability:
A foamed thermoplastic elastomer composition obtained by dry blending a foaming agent in advance with a thermoplastic elastomer composition obtained by melt-kneading components other than the foaming agent was used. A 5 mm sheet was extruded at a die outlet resin temperature of 200-220 ° C. The presence or absence of drawdown and the surface appearance and shape of the molded product were visually observed and evaluated according to the following criteria.
○: There is no drawdown, the specularity of the surface of the molded product is good, the shape is stable, and no flaws are generated.
X: There is at least one defect that there is a drawdown, the surface of the molded product is poor in specularity, a pattern is generated, an edge is not clearly formed, a spot is noticeable, and a spot is generated.

(3) Injection moldability:
Using a foamed thermoplastic elastomer composition obtained by dry blending a foaming agent in advance with a thermoplastic elastomer composition obtained by melt-kneading components other than the foaming agent, a sheet of 130 mm × 130 mm × 2 mm with a 120 t injection molding machine Was injection molded at a nozzle and cylinder temperature of 200-220 ° C. The appearance of the molded product was visually observed, and the presence or absence of flow marks, sink marks, and bumps was evaluated according to the following criteria.
◯: The surface of the molded product has good specularity, and no flaws are generated.
X: A pattern due to a flow mark or material peeling occurs on the surface of the molded product, and the irregularities are conspicuous.

(4) Peel strength (heat fusion with polypropylene)
A core material (polypropylene) is injection-molded in advance, and the molded product is inserted into the mold, and then the surface layer material (components other than the foaming agent is melt-kneaded in the gap between the molded product and the mold. A foamed thermoplastic elastomer composition obtained by dry blending a foaming agent in advance with the thermoplastic elastomer composition obtained above was injection molded to obtain a composite injection molded article. A strip-shaped test piece having a width of 25 mm and a length of 100 mm was punched from the composite injection-molded product obtained above. About the test piece obtained above, the skin material layer and the core material layer were subjected to a tensile test in a 180 ° direction at a tensile speed of 200 mm / min, and the peel strength at the fusion interface of the skin material layer / core material layer (kg / 25 mm ) Was measured.

2.
Used raw material component (a):
(A-1) Nordel IP 4760P (manufactured by DuPont Dow Elastomer Japan);
Ethylene / propylene / ethylidene norbornene copolymer rubber (EPDM) polymerized using a metallocene catalyst, density 0.88 g / cm ³ , Mooney viscosity ML _{1 + 4} (125 ° C.) 70 (ASTM D-1646), mass average molecular weight 210,000, ethylene content 67% by mass, ENB content 4.9% by mass, melting point 5 ° C.
(A-2) Nordel IP 4520 (manufactured by DuPont Dow Elastomer);
Ethylene / propylene / ethylidenenorbornene copolymer rubber (EPDM) polymerized using a metallocene catalyst, density 0.86 g / cm ³ , Mooney viscosity ML _{1 + 4} (125 ° C.) 20 (ASTM D-1646), weight average molecular weight 115,000, ethylene content 50% by mass, ENB content 4.9% by mass, melting point cannot be measured (because crystallinity is less than 1% by mass).

Comparative component (a ′):
EP57P (manufactured by JSR); ethylene / propylene / ethylidene norbornene copolymer rubber (EPDM) polymerized using a nonmetallocene catalyst (Ziegler catalyst), specific gravity 0.86, Mooney viscosity ML _{1 + 4} (100 ° C.) 88 (ASTM D-1646), iodine value 15, MFR (230 ° C., 21.18N load) 0.4 g / 10 min, hardness 55 (JIS A), ethylene content 66 mass%, ENB content 4.5 mass %.

Component (b):
Novatec BC08AHA (manufactured by Nippon Polychem Co., Ltd.); polypropylene; density: 0.902 g / cm ³ , hardness 94 (Shore A), MFR (230 ° C., 21.18 N load) 80 g / 10 min, weight average molecular weight 100,000 Melting point 160 ° C.

Component (c):
Tackirol 201 (manufactured by Taoka Chemical Co., Ltd.); alkylphenol formaldehyde resin:

Ingredient (e):
(E-1) Zinc oxide: 2 types of zinc oxide (manufactured by Sakai Chemical Co., Ltd.)
(E-2) stannous chloride: anhydrous stannous chloride (manufactured by Showa Kako Co., Ltd.)

Component (f):
PW-90 (Idemitsu Kosan Co., Ltd.); paraffin oil

Ingredient (h):
METABLEN A3000 (Made by Mitsubishi Rayon Co., Ltd., a mixture of methyl methacrylate / dodecyl methacrylate / tridecyl methacrylate copolymer and polytetrafluoroethylene)

Component (i):
(I-1) Master batch ("Fine blow S20N" manufactured by Mitsubishi Chemical Corporation) containing 20% by mass of an organic and inorganic mixed foaming agent ("Fine Cellol 100" manufactured by Mitsubishi Chemical Corporation)
(I-2) Masterbatch containing 20% by mass of azodicarboxylic acid amide (“Fine Blow BX037” manufactured by Mitsubishi Chemical Corporation)
(I-3) Tap water

Examples 1-22 and Comparative Examples 1-17
Each component is charged into a 3 L pressurized kneader type mixer at a component ratio (parts by mass) shown in any one of Tables 1 to 7, and melt kneaded at a kneading temperature of 180 to 200 ° C. and a kneading time of 10 to 30 minutes. And pelletized. Next, a foaming agent was mixed with the obtained pellets, and injection molding and press molding were performed to prepare test pieces, which were subjected to respective tests. The evaluation results are shown in any one of Tables 1-7.

As is clear from Tables 1 to 4, the thermoplastic elastomer composition of the present invention had good characteristics (Examples 1 to 22).

Further, as a recycling test for the thermoplastic elastomer composition of the present invention, the thermoplastic elastomer composition of the present invention (Example 19) once molded was foamed at a recycling rate of 5% by mass, 15% by mass, and 30% by mass (1). When magnification, (2) extrusion moldability, (3) injection moldability, and (4) heat-fusibility with polypropylene were evaluated, at a recycling rate of 5% by mass, (1) 2.2%, (2) ○ (3) ○, (4) 4.7 kg / 25 mm. At a recycling rate of 15% by mass, (1) 2.1%, (2) ○, (3) ○, and (4) 4.6 kg / 25 mm. When the recycling rate was 30% by mass, they were (1) 2.2%, (2) ○, (3) ○, and (4) 4.7 kg / 25 mm. The recyclability of the composition of the present invention is good.
Here, the recycling rate is a value defined by the following equation.
Recycling rate = mass of recycled material / (mass of virgin material + mass of recycled material) x 100

On the other hand, as shown in Tables 5 to 7, the comparative examples had problems in any of expansion ratio, heat fusion property with polypropylene, injection moldability, and extrusion moldability.

Further, when all 5 parts by mass of the foaming agent in Example 19 were replaced with thermal expansion microcapsules (Expansel 092DU-120, manufactured by Expancel), the heat-fusibility (peel strength) was 1.8 kg / It has fallen to 25 mm.

The thermoplastic elastomer composition of the present invention has a stable foaming characteristic and extremely excellent composite moldability with polypropylene, excellent oil resistance, and excellent flexibility and moldability. Therefore, materials such as automobile parts and elastic polymer parts are used. Can be suitably used.

Claims (4)

(A) 100 parts by mass of ethylene / α-olefin / non-conjugated polyene copolymer rubber polymerized using a metallocene catalyst,
(B) 20 to 350 parts by mass of a polypropylene resin,
(C) 2 to 25 parts by mass of an alkylphenol formaldehyde resin crosslinking agent,
(H) 0.05 to 30 parts by mass of an acrylic-modified polytetrafluoroethylene polymer, and (i) 0.01 to 10 parts by mass of a foaming agent other than the thermal expansion microcapsule,
A foamed thermoplastic elastomer composition for composite molding with polypropylene, comprising:
2. The foamed thermoplastic elastomer for composite molding with polypropylene according to claim 1, wherein the foaming agent other than the component (i) thermal expansion microcapsule is a mixture of an organic foaming agent and an inorganic foaming agent. Composition.
Recycled material of the thermoplastic elastomer composition according to claim 1 or 2 to 5 to 50% by mass, and
The virgin material 95-50 mass% of the thermoplastic-elastomer composition of Claim 1 or 2
A foamed thermoplastic elastomer composition for composite molding with polypropylene according to claim 1 or 2 .
A composite molded body of the foamed thermoplastic elastomer composition according to any one of claims 1 to 3 and polypropylene.