Retardation film web, circularly polarizing plate and organic EL panel
View Patent ↗The present invention provides a retardation film web having sufficient reversed wavelength dispersion characteristics and favorable for film lamination according to a roll-to-roll system. A retardation film web of the present invention includes a polycarbonate resin or a polyester carbonate resin, an orientation angle θ which is an angle between a slow axis and a width direction satisfies the following formula (I), and a ratio of an in-plane retardation R450 measured at a wavelength of 450 nm to an in-plane retardation R550 measured at a wavelength of 550 nm satisfies the following formula (II): 38°≦θ≦52° (I) R450/R550<1 (II).
1. A retardation film web, comprising:
a polycarbonate resin or a polyester carbonate resin,
wherein an orientation angle θ which is an angle between a slow axis and a width direction satisfies formula (1):
38°≦θ≦52° (I)
and
a ratio of an in-plane retardation R450 measured at a wavelength of 450 nm to an in-plane retardation R550 measured at a wavelength of 550 nm satisfies formula (II):
R450/R550<1 (II),
wherein the polycarbonate resin or the polyester carbonate resin comprises a structural unit derived from a dihydroxy compound having a cyclic ether structure.
2. The retardation film web according to claim 1 ,
wherein a glass transition temperature of the polycarbonate resin or the polyester carbonate resin is 190° C. or lower.
3. The retardation film web according to claim 1 ,
wherein the polycarbonate resin or the polyester carbonate resin comprises a structural unit having a 9,9-diarylfluorene structure.
4. The retardation film web according to claim 1 ,
wherein the polycarbonate resin or the polyester carbonate resin comprises a structural unit having a bonding structure represented by structural formula (1):
—CH 2 —CH 2 —O— (1).
5. The retardation film web according to claim 3 ,
wherein the polycarbonate resin or the polyester carbonate resin comprises a structural unit derived from a dihydroxy compound represented by formula (2):
wherein R 1 to R 4 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group having from 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having from 6 to 20 carbon atoms, or a substituted or unsubstituted aryl group having from 6 to 20 carbon atoms, and as four substituents of benzene rings, the same or different groups thereof are arranged,
X represents a substituted or unsubstituted alkylene group having from 2 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having from 6 to 20 carbon atoms, or a substituted or unsubstituted arylene group having from 6 to 20 carbon atoms; and
m and n each independently indicate an integer of from 0 to 5.
6. The retardation film web according to claim 1 ,
wherein the polycarbonate resin or the polyester carbonate resin comprises a structural unit derived from a dihydroxy compound represented by formula (3):
H—(O—R 5 ) p —OH (3),
wherein R 5 represents a substituted or unsubstituted alkylene group having from 2 to 10 carbon atoms; and
p indicates an integer of from 2 to 100.
7. The retardation film web according to claim 1 ,
wherein the polycarbonate resin or the polyester carbonate resin comprises a structural unit derived from a dihydroxy compound represented by structural formula (6):
8. The retardation film web according to claim 1 ,
wherein the polycarbonate resin or the polyester carbonate resin comprises a structural unit derived from a dihydroxy compound represented by formula (4):
9. The retardation film web according to claim 1 ,
wherein the retardation film web has a thickness of 100 μm or less, and
the in-plane retardation R550 thereof measured at a wavelength of 550 nm is from 100 to 160 nm.
10. A laminate film web, comprising:
the retardation film web according to claim 1 ; and
a polarizing film web,
wherein the retardation film web is laminated with the polarizing film web having an absorption axis in any of a longitudinal direction and a width direction thereof, in such a manner that their longitudinal directions are aligned with each other.
11. A circularly polarizing plate obtained by cutting the laminate film web according to claim 10 .
12. The circularly polarizing plate according to claim 11 , the circularly polarizing plate has a thickness of 200 μm or less.
13. An organic EL panel, comprising:
the circularly polarizing plate according to claim 11 .
14. A method for producing a circularly polarizing plate, the method comprising:
feeding, in a longitudinal direction thereof, a retardation film web comprising a polycarbonate resin or a polyester carbonate resin, in which an orientation angle θ which is an angle between a slow axis and a width direction satisfies formula (I) of
38°≦θ≦52° (I), and
a ratio of an in-plane retardation R450 measured at a wavelength of 450 nm to an in-plane retardation R550 measured at a wavelength of 550 nm satisfies formula (II):
R450/R550<1 (II);
feeding, in a longitudinal direction thereof, a polarizing film web having an absorption axis in any of the longitudinal direction and a width direction thereof; and
laminating the retardation film web and the polarizing film web in such a manner that their longitudinal directions are aligned with each other to thereby continuously form a laminate film,
wherein the polycarbonate resin or the polyester carbonate resin comprises a structural unit derived from a dihydroxy compound having a cyclic ether structure.