US 12,139,570 B2
Retardation film and production method for retardation film
Takeshi Asada, Tokyo (JP); Hironari Sudeji, Tokyo (JP); Kensaku Fujii, Tokyo (JP); Yusuke Yasu, Tokyo (JP); and Hiroya Nishioka, Tokyo (JP)
Assigned to ZEON CORPORATION, Chiyoda-ku (JP)
Appl. No. 16/981,693
Filed by ZEON CORPORATION, Tokyo (JP)
PCT Filed Mar. 18, 2019, PCT No. PCT/JP2019/011299
§ 371(c)(1), (2) Date Sep. 17, 2020,
PCT Pub. No. WO2019/181893, PCT Pub. Date Sep. 26, 2019.
Claims priority of application No. 2018-051030 (JP), filed on Mar. 19, 2018; and application No. 2018-225494 (JP), filed on Nov. 30, 2018.
Prior Publication US 2021/0032396 A1, Feb. 4, 2021
Int. Cl. C08F 297/04 (2006.01); B29C 48/00 (2019.01); B29C 48/88 (2019.01); B29C 55/06 (2006.01); C08J 5/18 (2006.01); G02B 1/04 (2006.01); G02B 5/30 (2006.01); B29K 25/00 (2006.01); B29K 96/04 (2006.01); B29K 105/00 (2006.01)
CPC C08F 297/04 (2013.01) [B29C 48/0018 (2019.02); B29C 48/914 (2019.02); B29C 55/06 (2013.01); C08J 5/18 (2013.01); G02B 1/04 (2013.01); G02B 5/3083 (2013.01); B29K 2025/00 (2013.01); B29K 2096/04 (2013.01); B29K 2105/0085 (2013.01); B29K 2995/0034 (2013.01); C08J 2347/00 (2013.01)] 14 Claims
 
1. A phase difference film composed of a resin C containing a copolymer P including a polymerization unit A and a polymerization unit B wherein the polymerization unit A is an aromatic vinyl-based unit and the polymerization unit B is a hydrogenated chain conjugated diene-based unit,
the phase difference film including a lamellar phase separation structure that generates a structural birefringence,
the phase separation structure including a phase (A) having the polymerization unit A as a main component and a phase (B) having the polymerization unit B as a main component,
an in-plane direction retardation Re(550) measured at a wavelength of 550 nm being 0 nm or more and 10 nm or less,
a thickness-direction retardation Rth(550) measured at a wavelength of 550 nm being 80 nm or more and 300 nm or less, and
the phase difference film satisfying the following formulae (1A) and (2), or the following formulae (1B) and (2),
f(A)>0.5  (1A)
f(B)>0.5  (1B)
D(A)>D(B)  (2)
wherein
f(A) represents a total weight ratio of the polymerization unit A in the copolymer P,
f(B) represents a total weight ratio of the polymerization unit B in the copolymer P,
D(A)=ReA(450)/ReA(550),
D(B)=ReB(450)/ReB(550),
ReA(450) represents an in-plane direction retardation (nm) of a film (A) formed from a polymer (A) composed of the polymerization unit A measured at a wavelength of 450 nm,
ReA(550) represents an in-plane direction retardation (nm) of the film (A) measured at a wavelength of 550 nm,
ReB(450) represents an in-plane direction retardation (nm) of a film (B) formed from a polymer (B) composed of the polymerization unit B measured at a wavelength of 450 nm, and
ReB(550) represents an in-plane direction retardation (nm) of the film (B) measured at a wavelength of 550 nm.