Retardation element
A retardation element containing a liquid crystalline compound, and at least one compound selected from the group consisting of a compound represented by the following formula (1), a compound represented by the following formula (2) and a compound represented by the following formula (3). In the formula (1), n represents an integer of 3 to 10 and R 2 represents a —CH 2 —CH 2 — group, a —CH 2 —CH(CH 3 )— group or a —CH 2 —CH 2 —CH 2 — group. In the formula (2), R 3 represents a —(CH 2 ) p — group or a phenylene group and p represents an integer of 4 to 8. In the formula (3), R 4 represents a substituted phenylene group. In the formulas (1) to (3), R 1-1 , R 1-2 and R 1-3 each represent an alkyl group having a branched structure having 5 or more carbon atoms and R 1-1 , R 1-2 and R 1-3 may be the same or different.
1. A retardation element,
which comprises a blend of a liquid crystalline compound and at least one compound selected from the group consisting of a compound represented by the following formula (1), a compound represented by the following formula (2) and a compound represented by the following formula (3):
wherein in the formula (1), n represents an integer of 3 to 10 and R 2 represents a —CH 2 —CH 2 — group, a —CH 2 —CH(CH 3 )— group or a —CH 2 —CH 2 —CH 2 — group,
in the formula (2), R 3 represents a —(CH 2 ) p — group or a phenylene group and p represents an integer of 4 to 8,
in the formula (3), R 4 represents a substituted phenylene group, and
in the formulas (1) to (3), R 1-1 , R 1-2 and R 1-3 each represent an alkyl group having a branched structure having 5 or more carbon atoms and R 1-1 , R 1-2 and R 1-3 may be the same or different,
wherein the retardation element has excellent heat resistance, exhibits little variation in its retardation value in high-temperature atmospheres, and can maintain stable optical properties,
wherein the liquid crystalline compound is a polymerizable liquid crystal and said polymerizable liquid crystal is polymerized, and
wherein the polymerizable liquid crystal is a polymerizable liquid crystal represented by the following formula (4):
wherein q and r each represent an integer of 1 to 10, X represents —COO— or —O—, Y represents —OC(O)O— or —O—, Z represents —COO or —OCO—, R 5 represents a phenylene group, R 6 represents a substituted phenylene group, a substituted biphenylene group or a fluorenyl group, R 7 represents —H, —(CH 2 ) w —CH 3 or —COO—(CH 2 ) w —CH 3 and w represents an integer of 0 to 11.
2. The retardation element according to claim 1 ,
wherein the diester compound represented by the formula (1) is triethylene glycol di-2-ethylhexanoate, tetraethylene glycol di-2-ethylhexanoate, triethylene glycol di-2-ethylbutyrate, tetraethylene glycol di-2-ethylbutyrate, pentaethylene glycol di-2-ethylhexanoate, octaethylene glycol di-2-ethylhexanoate, nonaethylene glycol di-2-ethylhexanoate or decaethylene glycol di-2-ethylhexanoate.
3. The retardation element according to claim 1 ,
wherein the diester compound represented by the formula (2) is bis(2-ethylhexyl) adipate, bis(2-ethylbutyl) adipate, bis(2-ethylhexyl) azelate, bis(2-ethylbutyl) azelate, di-2-ethylhexyl sebacate, di-2-ethylbutyl sebacate, di-2-ethylhexyl phthalate or di-2-ethylbutyl phthalate.
4. The retardation element according to claim 1 ,
wherein the triester compound represented by the formula (3) is tri-2-ethylhexyl trimellitate or tri-2-ethylbutyl trimellitate.
5. The retardation element according to claim 1 ,
wherein the content of at least one compound selected from the group consisting of the compound represented by the formula (1), the compound represented by the formula (2) and the compound represented by the formula (3) is 0.1 to 300 parts by weight with respect to 100 parts by weight of the liquid crystalline compound.
6. A retardation element with an adhesive layer, comprising the retardation element according to claim 1 , 2 , 3 , 4 , or 5 , and an adhesive layer,
wherein the adhesive layer is formed on at least one surface of the retardation element, and contains a copolymer of a plurality of monomers including acrylic acid.
7. A composite retardation element, comprising a plurality of layers laminated,
wherein at least one layer is the retardation element with an adhesive layer according to claim 6 .
8. An optical element,
which is a laminate of the retardation element with an adhesive layer according to claim 6 and a polarizing plate.
9. An image display device,
which comprises the retardation element with an adhesive layer according to claim 6 .
10. A liquid crystal display,
which comprises the retardation element with an adhesive layer according to claim 6 .
11. A composite retardation element, comprising a plurality of layers laminated,
wherein at least one layer is the retardation element according to claim 1 , 2 , 3 , 4 , or 5 .
12. An optical element,
which is a laminate of the composite retardation element according to claim 11 and a polarizing plate.
13. An image display device,
which comprises the composite retardation element according to claim 11 .
14. A liquid crystal display,
which comprises the composite retardation element according to claim 11 .
15. An optical element,
which is a laminate of the retardation element according to claim 1 , 2 , 3 , 4 , or 5 and a polarizing plate.
16. An image display device,
which comprises the optical element according to claim 15 .
17. A liquid crystal display,
which comprises the optical element according to claim 15 .
18. An image display device,
which comprises the retardation element according to claim 1 , 2 , 3 , 4 , or 5 .
19. A liquid crystal display,
which comprises the retardation element according to claim 1 , 2 , 3 , 4 , or 5 .