Ethylene copolymer with improved impact resistance
Provided are ethylene copolymers with excellent impact resistance. More specifically, provided are ethylene copolymers satisfying certain correlation between the falling dart impact strength (F) or high rate impact resistant breakage energy (E) and Vicat softening point. The ethylene copolymers with improved impact properties are applicable to film, injection, compound, sheet, roto, pipe or blow molding.
1. Copolymer of ethylene with (C3˜C18) α-olefin comonomer, having a density of 0.900 to 0.910 g/cm 3 , and falling dart impact strength (F) satisfying the correlation with Vicat softening point as expressed by Formulas (1) and (2):
F≧ 0.55 ×e (9.3011/(1+((V−59.4592)/76.3517) 2 )) +15 [Formula 1]
F≦ 1.7 ×e (9.3011/1+((V−59.4592)/76.3517) 2 )) +200 [Formula 2]
wherein, V represents Vicat softening point measured according to ASTM D 1525; and F represents falling dart impact strength measured according to ASTM D1709.
2. The ethylene copolymer according to claim 1 , wherein the (C3˜C18) α-olefin comonomer is selected from propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, or mixtures thereof.
3. The ethylene copolymer according to claim 2 , wherein the content of α-olefin comonomer is from 1 to 40% by weight.
4. The ethylene copolymer according to claim 3 , wherein the content of α-olefin comonomer is from 1 to 30% by weight.
5. The ethylene copolymer according to claim 4 , which contains 0.1 to 3.0% by weight of extractable substances, determined by measurement of volatiles, wherein the measurement of volatiles is determined by analytic method of temperature rising elution fractionation applying elution at 35° C. for 10 minutes to the overall crystallization peak.
6. The ethylene copolymer according to claim 5 , satisfying Formulas (1), (2) and (3):
F≦ 1.5 ×e (9.3011/(1+((V−59.4592)/76.3517) 2 )) +150 [Formula 3]
wherein, V represents Vicat softening point measured according to ASTM D 1525; and F represents falling dart impact strength measured according to ASTM D1709.
7. The ethylene copolymer according to claim 6 , satisfying Formula (4) as well as Formulas (1) to (3):
F≦ 1.3 ×e (9.3011/(1+((V−59.4592)/76.3517) 2 )) +100 [Formula 4]
wherein, V represents Vicat softening point measured according to ASTM D 1525; and F represents falling dart impact strength measured according to ASTM D1709.
8. The ethylene copolymer according to claim 7 , which has Haze of 2˜16 measured according to ASTM D1003.
9. The ethylene copolymer according to claim 5 , of which the high rate impact resistant breakage energy (E) value satisfies Formulas (5) and (6):
E≧ 0.9×(−0.3306 V+ 57.898) [Formula 5]
E≧ 1.2×(−0.3306 V+ 57.898) [Formula 6]
wherein, V represents Vicat softening point measured according to ASTM D 1525; and E represents high rate impact resistant breakage energy value measured according to ASTM D3763.
10. Blown film, manufactured by extruding the ethylene copolymers according to claim 1 .
11. Sheet products, manufactured by applying the ethylene copolymers according to claim 1 under extrusion molding.