Lg Chem, Ltd

Sang-Eun An

Kyung-Seop Noh

Nan-Young Lee

Won-Hee Kim

Sang-Jin Jeon

Choong-Hoon Lee

Cheon-Il Park

Kwang-Seung Park

Sang-Choll Han

Yune-Hyoun Kim

Seung-Ki Park

The present description relates to an olefin block copolymer having excellences in elasticity and heat resistance and its preparation method. The olefin block copolymer includes a plurality of blocks or segments, each of which includes an ethylene or propylene repeating unit and an &#x3b1;-olefin repeating unit at different weight fractions. The olefin block copolymer has a density of 0.85 to 0.92 g/cm, and density X (g/cm) and TMA (Thermal Mechanical Analysis) value Y (&#xb0; C.) satisfy a defined relationship.

Olefin block copolymer and preparation method thereof

The present description relates to an olefin block copolymer having excellences in elasticity, heat resistance, and processability. The olefin block copolymer includes a plurality of blocks or segments, each of which includes an ethylene or propylene repeating unit and an &#x3b1;-olefin repeating unit at different weight fractions. In the olefin block copolymer, a first derivative of the number Y of short-chain branches (SCBs) per 1,000 carbon atoms of each polymer chain contained in the block copolymer with respect to the molecular weight X of the polymer chains is a negative or positive number of &#x2212;1.5&#xd7;10or greater; and the first derivative is from &#x2212;1.0&#xd7;10to 1.0&#xd7;10in the region corresponding to the median of the molecular weight X or above.

Olefin block copolymer

The present description relates to an olefin block copolymer preferably useful to form nonslip pads due to excellences in elasticity and heat resistance, and a sheet-shaped molded body comprising the olefin block copolymer The olefin block copolymer includes a plurality of blocks or segments, each of which includes an ethylene or propylene repeating unit and an &#x3b1;-olefin repeating unit at different weight fractions. The olefin block copolymer satisfies a defined relationship when a load of 5 to 10 kg is applied to a sheet-shaped molded body of the block copolymer for 12 hours or longer at a temperature of 60&#xb0; C. or higher, and then removed.

Olefin block copolymer and sheet-shaped molded body

Provided is a backlight unit. The backlight unit includes a light source, an optical member configured to uniformly distribute light emitted from the light source, and at least two condensing films configured to condense light from the optical member. Hetero-conic lenses are two-dimensionally arranged on a surface of each of the condensing films, and each of the hetero-conic lenses is formed by combining a first conic lens expressed by Formula (1) below and a second conic lens expressed by Formula (2) below: 

Backlight unit comprising condensing film having hetero-conic lenses

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Daejeon, South Korea

Sang-Eun An