JP4828855B2 - Thermoplastic elastomer composition and molded article thereof - Google Patents

Description

  The present invention relates to an olefinic thermoplastic elastomer composition and a molded article thereof.

  Conventionally, as an automotive part, an electric / electronic part, or a building part, an extrusion vulcanized molded article made of a rubber compound of ethylene / propylene / non-conjugated diene terpolymer (EPDM) has a low hardness and rubber. It has been used in parts that require elasticity.

  On the other hand, instead of vulcanized rubber using ethylene / propylene / non-conjugated diene terpolymer (EPDM) as a sealing material for various applications, from the viewpoint of productivity, environmental friendliness and weight reduction, Thermoplastic elastomers (compositions) that do not require a vulcanization process are beginning to be used.

  As a technique relating to the composition of the thermoplastic elastomer, a technique for dynamically cross-linking an ethylene / propylene (non-conjugated diene) copolymer and a crystalline polyolefin is a known technique. In general, conventional thermoplastic elastomers have a problem in that the eyes adhere to the dies at the time of extrusion molding to deteriorate the appearance of the molded product. In order to improve the corners of the eyes, by reducing the amount of the crosslinking agent added during dynamic crosslinking, the corners of the eyes are reduced and the moldability is improved. However, by reducing the addition amount of the crosslinking agent, the rubber elasticity tends to deteriorate, and there is a case where the balance with the moldability cannot be achieved.

  As an improvement, as in JP-A No. 2001-123027 (Patent Document 1), in an extruder that performs dynamic cross-linking, a method is proposed in which resin is side-fed from a barrel in the middle to improve equal extrusion characteristics to the eyes. . However, with such a method, it is difficult to place a side feed of the resin and kneading. Moreover, since resin is added in the middle, there is a concern about deterioration of physical properties such as an increase in hardness.

Under such circumstances, a non-crosslinked thermoplastic elastomer containing a high molecular weight component is devised without adding a crosslinking agent in ethylene or propylene, and the rubber elasticity does not occur in the eyes and the rubber elasticity is a crosslinked thermoplastic elastomer. Something that is normal is being developed.
JP 2001-123027 A

  The present invention is intended to solve the problems associated with the prior art of the crosslinked thermoplastic elastomer as described above, which is non-crosslinked, and without adding a high molecular weight component as a rubber component. It is an object of the present invention to provide a thermoplastic elastomer composition excellent in the above and a molded product thereof.

The thermoplastic elastomer of the present invention comprises 10 to 50 parts by weight of a polybutene-1 resin (A) and a butene-1 content of 50 mol% to 80 mol% (excluding 80 mol%). The α-olefin random copolymer (B) is composed of 90 to 50 parts by weight, preferably a thermoplastic elastomer composition in which the α-olefin is propylene and is a molded product thereof. .

  Since the thermoplastic elastomer composition according to the present invention is excellent in appearance and extrusion moldability of a molded product, it can be easily molded into a desired molded product. Molded products are used for automotive parts, industrial machine parts, electrical and electronic parts, civil engineering and building parts, medical parts, etc., and are required to have flexibility, mechanical strength, shape recovery, rebound resilience, high temperature mechanical properties, etc. Things.

  Thermoplastic elastomers have physical properties similar to rubber, such as flexibility and impact resilience, and can be processed as thermoplastics as opposed to ordinary rubber. It is made in a large dictionary (Maruzen Co., Ltd., published in 1994).

The thermoplastic elastomer composition according to the present invention will be described.
The thermoplastic elastomer composition according to the present invention comprises a polybutene-1 resin (A) and a butene-1 / α-olefin random copolymer (B) as components.

Polybutene-1 resin (A)
As the polybutene-1 resin (A) used in the present invention, (co) polymers such as (1), (2) and (3) are preferably used.
(1) Butene-1 homopolymer, (2) Random copolymer of butene-1 with 10 mol% or less of other olefin, (3) Butene-1 with 30 mol% or less of other α-olefin Specific examples of the block copolymer and the α-olefin include ethylene, propylene, 4-methyl-1-pentene, 1-hexene, and 1-octene. Among these, a homopolymer of butene-1 or a random copolymer of butene-1 and ethylene or propylene is preferable. One type of polybutene-1 resin may be used, or two or more types may be used. The MFR (melt flow rate; 230 ° C., 2.16 kgf) of the polybutene-1 resin is in the range of 0.01 to 100, preferably 0.05 to 30.

Butene-1, α-olefin random copolymer (B)
The butene-1 / α-olefin random copolymer (B) used in the present invention is obtained by a known polymerization technique, and the proportion of butene-1 is 50% by weight or more. Specifically, ethylene, propylene, 4-methyl-1-pentene, 1-hexene, 1-octene and the like can be mentioned. Among these, a random copolymer of butene-1 and propylene is preferable. One type of butene-1α-olefin random copolymer may be used, or two or more types may be used. The MFR (melt flow rate; 230 ° C., 2.16 kgf) of the butene-1 / α-olefin random copolymer is in the range of 0.01 to 100, preferably 0.05 to 30. The butene-1 content of the butene-1α-olefin random copolymer (B) is 40 mol% or more and less than 90 mol, preferably 50 mol% to 80 mol%.

  The blending amount of the butene-1 / α-olefin random copolymer (B) with respect to 1 to 99 parts by weight of the polybutene-1 resin (A) is 99 to 1 parts by weight. Preferably, the blending amount of the butene-1 / α-olefin random copolymer (B) is 95 to 5 parts by weight with respect to 5 to 95 parts by weight of the polybutene-1 resin (A). More preferably, considering flexibility, 90-50 parts by weight of a butene-1α-olefin random copolymer (B) with respect to 10-50 parts by weight of the butene-1 resin (A), more preferably polybutene. -1 resin (A) 20 to 40 parts by weight is 80 to 60 parts by weight of a butene-1α-olefin random copolymer (B).

  In the thermoplastic elastomer composition of the present invention, a softener may be used as a fluidity or hardness adjusting agent.

Specifically, petroleum-based softeners such as process oil, lubricating oil, paraffin, liquid paraffin, polyethylene wax, polypropylene wax, petroleum asphalt, and petroleum jelly;
Coal tar softeners such as coal tar and coal tar pitch;
Fatty oil softeners such as castor oil, linseed oil, rapeseed oil, soybean oil, coconut oil;
Tall oil;
Sub, (Factis);
Waxes such as beeswax, carnauba wax, lanolin;
Fatty acids and fatty acid salts such as ricinoleic acid, palmitic acid, stearic acid, barium stearate, calcium stearate, zinc laurate;
Naphthenic acid;
Pine oil, rosin or derivatives thereof;
Synthetic polymer materials such as terpene resin, petroleum resin, coumarone indene resin, atactic polypropylene;
Ester softeners such as dioctyl phthalate, dioctyl adipate, dioctyl sebacate;
Examples thereof include microcrystalline wax, liquid polybutadiene, modified liquid polybutadiene, liquid polyisoprene, terminal-modified polyisoprene, hydrogenated terminal-modified polyisoprene, liquid thiocol, and hydrocarbon-based synthetic lubricating oil. Among these, petroleum softeners, particularly process oils are preferably used.

In the thermoplastic elastomer composition according to the present invention, additives such as a nucleating agent, a slip agent, a filler, an antioxidant, a weathering stabilizer, a colorant, and the like, as long as necessary, do not impair the purpose of the present invention Can be blended.
Examples of the nucleating agent include phosphorus-based, sorbitol-based, aluminum-based, and talc fillers.

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.

  As the kneading apparatus for the thermoplastic elastomer according to the present invention, 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. The kneading temperature is not particularly limited, but a general kneading temperature of 160 to 300 ° C. is preferable.

  The melt flow rate (MFR; ASTM D 1238, 230 ° C., 2.16 kg load) of the thermoplastic elastomer according to the present invention is usually 0.01 to 1000 g / 10 minutes, preferably 0.02 to 500 g / 10 minutes. A thermoplastic elastomer having a melt flow rate in the above range is excellent in moldability.

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

  Polybutene-1 resin (A) used in Examples and Comparative Examples (BL2000 manufactured by Mitsui Chemicals, density 907 kg / m3, MFR = 0.2 g / 10 min, melting point 123 ° C.), butene-1α- Olefin Random Copolymer (B) (Butene-1 / Propylene Random Copolymer BL2281, manufactured by Mitsui Chemicals, Inc., butene-1 content 75 mol%, density 900 kg / m 3, MFR = 2.0 g / 10 min, melting point 71 ° C. ), Polypropylene resin (C) (E111G manufactured by Mitsui Chemicals, density 907 kg / m 3, MFR = 0.5 g / 10 min, melting point 160 ° C.), ethylene / propylene / non-conjugated polyene copolymer rubber (D) (ethylene) Content 78 mol%, 5-ethylidene-2-norbornene 4.5 wt%, Mooney viscosity ML (1 + 4) 100 ° C. 74, iodine value 13 g / 1 0 g) (oil extended amount): 40.5 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) Heat obtained in Examples and Comparative Examples Measurement of melt flow rate (MFR) of thermoplastic elastomer (TPE) compositions, hardness, tensile strength, elongation, compression set (CS) of molded articles made of thermoplastic elastomer compositions obtained in Examples and Comparative Examples Evaluation was performed according to the following method.

(1) Melt flow rate (MFR)
The melt flow rate of the thermoplastic elastomer composition was measured at 230 ° C. and a 2.16 kg load according to ASTM D1238.
(2) Hardness The hardness was measured as Shore A hardness or Shore D hardness according to JIS K6253.
For measurement, a sheet was prepared by a press molding machine, and the scale was read immediately after contact with the pressing needle using an A or D type measuring instrument.
(3) Tensile strength and elongation In accordance with JIS K6251, a tensile test was performed under the following conditions, and the tensile strength and elongation at break were measured.
In the test, a sheet was prepared by a press molding machine, and a JIS No. 3 test piece was punched out under the condition of a tensile speed of 500 mm / min.
(4) Compression set CS
In the test, a sheet was produced with a press molding machine, and in accordance with JIS K6262, 25% compression was performed with a spacer, and heat treatment was performed at 70 ° C. × 24 hours, 100 ° C. × 24 hours. Then, the thickness was measured.

[Example 1]
20 parts by weight of polybutene-1 resin (A),
80 parts by weight of a butene-1 / α-olefin random copolymer (B),
0.1 part by weight of a phenolic antioxidant [Nippon Ciba Geigy Co., Ltd., trade name: Irganox 1010] as an antioxidant,
Diazo weathering stabilizer [manufactured by Ciba Geigy Japan Ltd., trade name: Tinuvin 326] as a weathering agent and 0.1 part by weight of HALS weathering stabilizer [Sankyo Co., Ltd., trade name: Sanol LS-770] 0.05 weight Part,
Fatty acid amide type lubricant [manufactured by Lion Co., Ltd., trade name Armoslip CP] 0.3 parts by weight as a lubricant is 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 Granulation was performed at an amount of 30 kg / h] to obtain pellets of a thermoplastic elastomer composition.

A molded body obtained from the pellet-shaped thermoplastic elastomer composition was evaluated according to the above method.
The results are shown in Table 1.

[Example 2]
The same procedure as in Example 1 was performed except that 40 parts by weight of the polybutene-1 resin (A) and 60 parts by weight of the butene-1 / α-olefin random copolymer (B) were used. The results are shown in Table 1.

[Comparative Example 1]
The same procedure as in Example 1 was performed except that the polybutene-1 resin (A) in Example 1 was changed to a polypropylene resin (C). The results are shown in Table 1.

[Comparative Example 2]
The same procedure as in Example 1 was performed except that the butene-1 / α-olefin random copolymer (B) was changed to an ethylene / propylene / non-conjugated polyene copolymer rubber (D).
The results are shown in Table 1.

Claims (4)

Polybutene-1 resin (A) 10 to 50 parts by weight and butene-1 content is 50 mol% to 80 mol% (however, excluding 80 mol%) B) A thermoplastic elastomer composition comprising 90 to 50 parts by weight.   A thermoplastic elastomer composition wherein the α-olefin of the butene-1 • α-olefin random copolymer (B) according to claim 1 is propylene.   The heat according to claim 1 or 2, comprising 80 to 60 parts by weight of the butene-1α-olefin random copolymer (B) with respect to 20 to 40 parts by weight of the polybutene-1 resin (A). Plastic elastomer composition.   The thermoplastic-elastomer molded object formed by shape | molding the thermoplastic-elastomer composition of any one of Claims 1-3.