THERMOPLASTIC ELASTOMERIC COMPOSITION FOR VEHICLE MOUNTS WITH IMPROVED SURFACE ENERGY AND COMPRESSION SET, AND MOLDED ARTICLE INCLUDING THE SAME
Disclosed are a thermoplastic elastomeric composition for vehicle mounts which has improved surface energy and compression set while solving reduction in wear strength, by blending EPDM rubber, polypropylene, silicon, and poly(styrene-ethylene-butadiene-styrene) (SEBS) in appropriate amounts, and a molded article including the same.
1 . A thermoplastic elastomeric composition comprising:
80 parts by weight of ethylene propylene diene monomer (EPDM) rubber;
30 to 70 parts by weight of polypropylene (PP);
2 to 15 parts by weight of silicon; and
20 to 40 parts by weight of poly(styrene-ethylene-butadiene-styrene) (SEBS).
2 . The thermoplastic elastomeric composition of claim 1 , wherein the EPDM rubber comprises:
an amount of 50 to 70 wt % of polyethylene (PE);
an amount of 5 to 10 wt % of ethylidene norbornene (ENB); and
a balance of polypropylene (PP),
based on the total weight of the EPDM rubber.
3 . The thermoplastic elastomeric composition of claim 1 , further comprising additives,
wherein the additives comprise a crosslinking agent, a crosslinking assistant, a surface modifier, a lubricant, an antioxidant, a crosslinking accelerator, a filler, a UV stabilizer, and a plasticizer.
4 . The thermoplastic elastomeric composition of claim 3 , wherein the additives comprise:
an amount of 0.1 to 0.9 parts by weight of the crosslinking agent,
an amount of 0.1 to 0.5 parts by weight of the crosslinking assistant,
an amount of 1 to 3 parts by weight of the surface modifier,
an amount of 1 to 3 parts by weight of the lubricant,
an amount of 0.1 to 0.5 parts by weight of the antioxidant,
an amount of 1 to 3 parts by weight of the crosslinking accelerator,
an amount of 10 to 30 parts by weight of the filler,
an amount of 1 to 5 parts by weight of the UV stabilizer, and
an amount of 60 to 80 parts by weight of the plasticizer, based on 80 parts by weight of the EPDM rubber.
5 . The thermoplastic elastomeric composition of claim 1 , having surface energy of 20 to 35 mN/m.
6 . The thermoplastic elastomeric composition of claim 1 , having a water contact angle of 100 to 120° with a surface of a tail gate bumper, and a diiodo methane contact angle of 60 to 80° with the surface of the tail gate bumper.
7 . A molded article for vehicle mounts, comprising a thermoplastic elastomeric composition of claim 1 .
8 . The molded article of claim 7 , having tensile strength of 5 to 10 MPa and elongation of 400 to 600%, measured based on ISO 37.
9 . The molded article of claim 7 , having a compression set of 35 to 45%, measured based on ISO 815.
10 . A vehicle comprising a molded article of claim 7 .