JP2006104245A - Thermoplastic elastomer composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer containing less particles or fish eyes and excellent in surface appearance. <P>SOLUTION: This thermoplastic elastomer composition containing the following (A) to (C) and having 5-50 pts.wt. content of the (A), 50-95 pts.wt. content of the (B) (provided that the total amount of the (A) and (B) is 100 pts.wt.) and 1-20 pts.wt. (C) based on 100 pts.wt. total amount of the (A) and (B) is obtained by dynamic cross-linking. (A) An olefin-based resin, (B) An ethylene-α-olefin-based copolymer rubber, (C) A terpene-based resin having 50-150°C softening point measured in accordance with JIS K-2207 (1990). As the (A) olefin-based resin, a homopolymer or copolymer of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, etc., are cited, and among them, the polypropylene is preferable. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermoplastic elastomer composition. More specifically, the present invention is a thermoplastic elastomer composition excellent in tensile strength, compression set, flexibility, etc., and the surface of the extruded product is smooth and does not generate any spots or fish eyes. The present invention relates to a thermoplastic elastomer composition capable of obtaining an excellent molded body.

  Thermoplastic elastomers are excellent in properties such as tensile strength, compression set, and flexibility, and are easy to recycle, so home appliance parts (tubes), automobile parts (skin materials for doors, instrument panels, etc., weather strips) ), Building parts (gaskets, etc.), miscellaneous goods (grips such as ballpoint pens, etc.), etc., and especially widely used as an alternative material for vulcanized rubber and soft vinyl chloride. (Refer to Patent Document 1 and Patent Document 2) The thermoplastic elastomer having the above-described characteristics is used after being processed into various molded products. In particular, extrusion molded products such as sheet molded products and modified extrusion molded products are used. The appearance of the surface of the molded product is very important, and the surface of the molded product may be rough and minute protrusions called “butsu” or “fish eyes” may be generated, which may significantly impair the value of the product.

Japanese Patent No. 2891075 JP 2001-11249 A

  Under such circumstances, the problem to be solved by the present invention is a thermoplastic elastomer composition excellent in tensile properties, compression set, flexibility, and surface appearance. Therefore, the present invention resides in providing a thermoplastic elastomer composition capable of obtaining a molded article having excellent appearance.

That is, the present invention contains the following (A) to (C), the content of (A) is 5 to 50 parts by weight, and the content of (B) is 50 to 95 parts by weight (provided that ( The total amount of A) and (B) is 100 parts by weight), and the content of (C) per 100 parts by weight of the total amount of (A) and (B) is 1 to 20 and is obtained by dynamic crosslinking. The present invention relates to a thermoplastic elastomer composition.
(A) Olefin resin (B) Ethylene-α-olefin copolymer rubber (C) Terpene resin having a softening point of 50 to 150 ° C. measured according to JIS K-2207 (1990)

  According to the present invention, it is possible to provide a thermoplastic elastomer composition having less surface or fish eye and excellent surface appearance. The thermoplastic elastomer composition of the present invention is excellent in tensile properties, compression set, and flexibility, and a product using the thermoplastic elastomer composition is also excellent in appearance.

  The component (A) of the present invention is an olefin resin. Examples of the olefin resin include homopolymers or copolymers such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-decene. Of these, polypropylene is preferable.

  Polypropylene is a known polymer and is polymerized by a known polymerization method. When polymerizing propylene, you may copolymerize alpha olefins, such as ethylene, 1-butene, 1-pentene, 4-methyl 1-pentene. As the three-dimensional structure, an isotactic structure is preferable, but a syndiotactic structure, a mixture of these structures, or a structure partially including an atactic structure can also be used. Polypropylene is a polymer mainly composed of propylene, and is a propylene homopolymer, a propylene-α-olefin random copolymer or a block copolymer.

  The melt flow rate of polypropylene (measured at a temperature of 230 ° C. and a load of 21.18 N according to JIS K-7210) is usually 0.1 to 200 g / 10 minutes, but from the viewpoint of workability at the time of molding, Preferably it is 0.1-50 g / 10min, More preferably, it is 0.3-30g / 10min.

  Component (B) of the present invention: ethylene-α-olefin copolymer rubber contains an ethylene monomer unit and an α-olefin monomer unit, and is a copolymer rubber mainly composed of an olefin monomer unit. It is. Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-decene, and propylene is particularly preferable. In addition, as monomer units other than olefins, for example, non-conjugated diene units such as 1,4-hexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene and the like may be contained. For example, ethylene-propylene copolymer rubber (EPR) and ethylene-propylene-nonconjugated diene copolymer rubber (EPDM) can be used.

  From the viewpoint of enhancing the compression set resistance of the resulting thermoplastic elastomer composition, ethylene-propylene-nonconjugated diene copolymer rubber (EPDM) is preferred. The iodine value when ethylene-propylene-nonconjugated diene copolymer rubber (EPDM) is used is preferably 5 or more from the viewpoint of enhancing compression set resistance of the resulting thermoplastic elastomer composition. From the viewpoint of improving the weather resistance of the resulting thermoplastic elastomer composition, the iodine value is preferably 40 or less.

  The total amount of components (A) and (B) is 100 parts by weight. The flexibility of the thermoplastic elastomer obtained when the content of the component (A) is 5 to 50 parts by weight, the content of the component (B) is 50 to 95 parts by weight, and the component (A) is excessive. Compression set resistance decreases. On the other hand, when the component (A) is too small, the molding processability of the thermoplastic elastomer composition obtained is lowered.

Component (B): 100 ° C. Mooney viscosity (ML _{1 + 4} 100 ° C.) of the ethylene-α-olefin copolymer rubber is preferably 10 or more from the viewpoint of increasing the mechanical strength of the resulting thermoplastic elastomer composition. More preferably, it is 30 or more. From the viewpoint of enhancing the appearance of the obtained molded product, the Mooney viscosity is preferably 350 or less, more preferably 300 or less. In addition, this Mooney viscosity is measured on the conditions of the temperature of 100 degreeC according to ASTMD-927-57T.

  Component (B) of the present invention: ethylene-α-olefin copolymer rubber, from the viewpoint of enhancing moldability and flexibility of the resulting thermoplastic elastomer composition, ethylene-α-olefin copolymer rubber 100 The oil-extended ethylene-α-olefin copolymer rubber is preferably composed of 20 to 150 parts by weight of a mineral oil softener per part by weight. The mineral oil softener is selected from aroma, naphthenic, and paraffinic mineral oils that are usually blended in rubber. Among these mineral oils, paraffinic mineral oil is preferable from the viewpoint of enhancing the appearance and color tone of the molded product.

  Component (C) of the present invention is a terpene resin having a softening point of 50 to 150 ° C. measured according to JIS K-2207 (1990).

  The terpene resin is a resin made from terpene oil obtained from natural vegetable oil (pine, orange peel, etc.), and examples of the terpene oil include α-pinene, β-pinene, and dipentene. Examples of the component (C) of the present invention include homopolymers of these terpene oils, copolymers of terpene oils having different structures, and copolymers of terpene oils with phenols and other aromatic compounds. Further, those obtained by hydrogenating these polymers are also included.

  Component (C) has a softening point of 50 to 150 ° C., preferably 80 to 150 ° C., measured according to JIS K-2207 (1990). When the softening point is too small, the handling property of the terpene resin is inferior, the tackiness of the resulting thermoplastic elastomer composition is increased, or the heat resistance is lowered. On the other hand, a terpene resin having a high softening point is inferior in availability.

  Component (C) contains 1 to 20 parts by weight per 100 parts by weight of the total amount of components (A) and (B). When the component (C) is excessive, the mechanical properties of the thermoplastic elastomer composition obtained are lowered. On the other hand, if the component (C) is too small, the effect of reducing the irregularities and fish eyes generated on the surface of the molded article of the thermoplastic elastomer composition obtained is insufficient.

  The thermoplastic elastomer composition of the present invention is a crosslinked composition subjected to dynamic crosslinking. Here, dynamic crosslinking refers to, for example, melt-kneading the resin composition in the presence of an organic peroxide. Examples of the organic peroxide include 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne, 3-bis (t-butylperoxyisopropyl) benzene, 1,1-di (t-butylperoxy3,5,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (peroxybenzoyl) hexyne And dicumyl peroxide.

  The amount of the organic peroxide used for the dynamic crosslinking is 100 weights of the total amount of the component (A): olefin resin and the component (B): ethylene-α-olefin copolymer rubber from the viewpoint of improving the permanent strain resistance. Per part, preferably 0.01 parts by weight or more, more preferably 0.04 parts by weight or more, but from the viewpoint of improving molding processability, it is preferably 1.0 parts by weight or less, more preferably 0.5 parts by weight or less.

  For dynamic crosslinking in the presence of an organic peroxide, a crosslinking aid may be used in combination as necessary. Examples of the crosslinking aid include peroxide crosslinking aids such as N, N′m-phenylenebismaleimide, toluylenebismaleimide, p-quinonedioxime, nitrosobenzene, diphenylguanidine, trimethylolpropane; divinylbenzene, Examples thereof include polyfunctional vinyl monomers such as ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and allyl methacrylate.

  If necessary, the thermoplastic elastomer composition of the present invention may contain additives such as flame retardants, antistatic agents, heat stabilizers, anti-aging agents, release agents, and the like; pigments, etc. A resin component may be blended.

The thermoplastic elastomer composition of the present invention is a thermoplastic elastomer composition obtained by dynamically crosslinking the above (A) to (C). As the dynamic crosslinking apparatus, known apparatuses such as an open type mixing roll, a non-open type Banbury mixer, a kneader, an extruder, a twin screw extruder, and the like can be used. The temperature and time when the dynamic crosslinking treatment is performed using an organic peroxide is a temperature at which the half-life temperature of the organic peroxide used is less than 1 minute, usually 150 ° C. to 280 ° C., preferably 180 ° It is 1 to 30 minutes at 3O <0> C to 260 <0> C, preferably 3 to 20 minutes.
In the melt-kneading, all components to be kneaded may be melt-kneaded all at once, or components not selected after kneading some components may be added and melt-kneaded.

  The thermoplastic elastomer composition obtained by the present invention can be molded by a general extrusion molding machine and an injection molding machine used for processing a thermoplastic resin. In particular, it is suitable for extrusion molding and profile extrusion molding. Products include home appliance parts (tubes), automotive parts (skin materials such as doors and instrument panels, weather strips), building parts (gaskets, etc.), and miscellaneous goods (grips such as ballpoint pens).

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

[1] Evaluation method (1) Softening point of terpene resin The measurement was performed according to JIS K-2207.
(2) Melt flow rate (MFR)
In accordance with JIS K7210, a polypropylene resin is measured under the conditions of a load of 21.18 N and a temperature of 230 ° C., a polyethylene resin is measured under the conditions of a load of 21.18 N and a temperature of 190 ° C., and the thermoplastic elastomer composition is subjected to a load of 98.08 N. The temperature was measured at 230 ° C.
(3) Ratio of ethylene monomer unit amount to propylene monomer unit amount in ethylene-propylene-5-ethylidene-2-norbornene copolymer Measurement was performed by infrared spectroscopy.
(4) Mooney viscosity (ML _{1 + 4} 100 ° C)
Measurements were taken at 100 ° C. according to ASTM D-927-57T.
(5) Flexibility Durometer A hardness was measured according to ASTM D2240.
(6) Tensile test In accordance with JIS K-6251, the test was conducted using a JIS No. 3 dumbbell at a test speed of 200 mm / min.
(7) Measurement of lumps or fish eyes A thermoplastic elastomer composition sheet having a thickness of 1 mm, a width of 80 mm, and a length of 50 cm obtained by extrusion molding is visually observed. I counted the number of fish eyes.

[2] Raw material (1) Olefin resin Nobrene D101 (Homopolypropylene, MFR = 0.5 g / 10 min) manufactured by Sumitomo Chemical Co., Ltd.
(2) Ethylene-α-olefin copolymer rubber Esprene 670F manufactured by Sumitomo Chemical Co., Ltd. (oil-extended ethylene-propylene-5-ethylidene-2-norbornene copolymer rubber (ethylene ethylene-propylene-5-ethylidene- 2-norbornene copolymer (ethylene monomer unit / propylene monomer unit (weight ratio) = 70/30, iodine value = 12))) 100 parts by weight, extension oil 100 parts by weight, ML _{1 + 4} 100 ° C. = 53)
(3) Organic peroxide 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (manufactured by Kayaku Akzo Corporation)
(4) Crosslinking aid Trimethylolpropane trimethacrylate (Seiko Chemical High Cross M)
(7) Terpene resin Terpene resin (1): Yasuhara Chemical Co., Ltd. hydrogenated terpene resin Clearon P85 (softening point = 85 ° C)
Terpene resin (2): Yasuhara Chemical Co., Ltd. hydrogenated terpene resin Clearon P115 (softening point = 115 ° C)
Terpene resin (3): Yasuhara Chemical Co., Ltd. hydrogenated terpene resin Clearon P135 (softening point = 135 ° C)
Terpene resin (4): Yasuhara Chemical Co., Ltd. aromatic modified hydrogenated terpene resin Clearon M115 (softening point = 115 ° C)
Terpene resin (5): Yasuhara Chemical Co., Ltd. aromatic modified hydrogenated terpene resin Clearon K110 (softening point = 110 ° C)

Examples 1 to 5 and Comparative Example 1
The formulations shown in Table 1 were kneaded using a Banbury mixer, and the obtained kneaded material was passed through a roll to form a sheet, and then formed into square pellets with a sheet pelletizer. Subsequently, the square pellets were subjected to dynamic crosslinking treatment at a cylinder temperature of 200 ° C. in the presence of an organic peroxide using a twin screw extruder. As the organic peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane was used, and 0 per 100 parts by weight of the total amount of the olefin resin and the ethylene-α-olefin copolymer rubber. 2 parts by weight were blended to obtain a thermoplastic elastomer composition.
Further, the obtained thermoplastic elastomer composition was evaluated by preparing a sheet having a width of 80 mm and a thickness of 1 mm using a single screw extruder having a cylinder temperature of 220 ° C. The results are shown in Table 2.

酸化防止剤：チバスペシャリティケミカルズ（株）社製 ＩＲＧＡＮＯＸ１０１０
光安定剤(1)：住友化学工業（株）社製 ＳＵＭＩＳＯＲＢ３００
光安定剤(2)：チバスペシャリティケミカルズ（株）社製 ＴＩＮＵＶＩＮ６２２ＬＤ

Antioxidant: IRGANOX1010 manufactured by Ciba Specialty Chemicals Co., Ltd.
Light stabilizer (1): SUMISORB300 manufactured by Sumitomo Chemical Co., Ltd.
Light stabilizer (2): TINUVIN622LD manufactured by Ciba Specialty Chemicals Co., Ltd.

Claims (3)

The following (A) to (C) are contained, the content of (A) is 5 to 50 parts by weight, and the content of (B) is 50 to 95 parts by weight (however, (A) and (B )), And the thermoplastic elastomer composition obtained by dynamic crosslinking, wherein the content of (C) per 100 parts by weight of the total amount of (A) and (B) is 1-20. .
(A) Olefin resin (B) Ethylene-α-olefin copolymer rubber (C) Terpene resin having a softening point of 50 to 150 ° C. measured according to JIS K-2207 (1990) Oil-extended in which component (B) comprises 100 parts by weight of ethylene-α-olefin copolymer rubber and 20 to 150 parts by weight of a mineral oil softener and has a Mooney viscosity (ML _{1 + 4} 100 ° C.) of 20 to 350 The thermoplastic elastomer composition according to claim 1, which is an ethylene-α-olefin copolymer rubber. The ethylene-α-olefin copolymer rubber used in component (B) is at least one selected from ethylene-propylene-nonconjugated polyene copolymer rubber and / or ethylene and an α-olefin having 3 to 20 carbon atoms. The thermoplastic elastomer composition according to claim 1 or 2, comprising a copolymer rubber with an α-olefin.