Diisopropyl fumarate-cinnamic acid derivative copolymer and retardation film using the same

Patent metadata

Field	Value
Publication number	US-9321870-B2
Application number	US-201314415923-A
Country	US
Kind code	B2
Filing date	Jul 16, 2013
Priority date	Jul 20, 2012
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

To provide a novel diisopropyl fumarate-cinnamic acid derivative-based copolymer expected to be formed into a retardation film having excellent optical properties ensuring that, for example, the refractive index in the film thickness direction and the out-of-plane retardation are large and even in the form of a thin film, the film has a high out-of-plane retardation, and a retardation film using the same. The diisopropyl fumarate-cinnamic acid derivative-based copolymer contains: a diisopropyl fumarate residue unit; and a cinnamic acid residue unit or a cinnamic acid ester residue unit having an alkyl group with a carbon number of 1 to 6.

First claim

The invention claimed is:

1. A diisopropyl fumarate-cinnamic acid derivative-based copolymer, comprising:
a diisopropyl fumarate residue unit; and
a cinnamic acid residue unit or a cinnamic acid ester residue unit having an alkyl group with a carbon number of 1 to 6.

2. The diisopropyl fumarate-cinnamic acid derivative-based copolymer according to claim 1 , comprising:
from 50 to 99 mol % of the diisopropyl fumarate residue unit; and
from 1 to 50 mol % of the cinnamic acid residue unit or from 1 to 50 mol % of the cinnamic acid ester residue unit having an alkyl group with a carbon number of 1 to 6.

3. The diisopropyl fumarate-cinnamic acid derivative-based copolymer according to claim 1 ,
wherein a number average molecular weight in terms of standard polystyrene is from 30,000 to 500,000.

4. The diisopropyl fumarate-cinnamic acid derivative-based copolymer according to claim 1 , which is a copolymer selected from the group consisting of a diisopropyl fumarate-methyl cinnamate copolymer, a diisopropyl fumarate-ethyl cinnamate copolymer, and a diisopropyl fumarate-isopropyl cinnamate copolymer.

5. A retardation film comprising the diisopropyl fumarate-cinnamic acid derivative-based copolymer according to claim 1 .

6. The retardation film according to claim 5 ,
wherein when a refractive index in a fast axis direction in a film plane is denoted by nx, a refractive index in a film in-plane direction orthogonal thereto is denoted by ny, and a refractive index in a film thickness direction is denoted by nz, respective refractive indices satisfy relationship of nx≦ny<nz.

7. The diisopropyl fumarate-cinnamic acid derivative-based copolymer according to claim 1 , comprising:
the diisopropyl fumarate residue unit; and
the cinnamic acid residue unit.

8. The diisopropyl fumarate-cinnamic acid derivative-based copolymer according to claim 1 , comprising:
the diisopropyl fumarate residue unit; and
the cinnamic acid ester residue unit having an alkyl group with a carbon number of 1 to 6.

9. The diisopropyl fumarate-cinnamic acid derivative-based copolymer according to claim 1 , comprising:
from 50 to 99 mol % of the diisopropyl fumarate residue unit; and
from 1 to 50 mol % of the cinnamic acid residue unit.

10. The diisopropyl fumarate-cinnamic acid derivative-based copolymer according to claim 1 , comprising:
from 50 to 99 mol % the diisopropyl fumarate residue unit; and
from 1 to 50 mol % of the cinnamic acid ester residue unit having an alkyl group with a carbon number of 1 to 6.

11. The diisopropyl fumarate-cinnamic acid derivative-based copolymer according to claim 1 , which is a diisopropyl fumarate-methyl cinnamate copolymer.

12. The diisopropyl fumarate-cinnamic acid derivative-based copolymer according to claim 1 , which is a diisopropyl fumarate-ethyl cinnamate copolymer.

13. The diisopropyl fumarate-cinnamic acid derivative-based copolymer according to claim 1 , which is a diisopropyl fumarate-isopropyl cinnamate copolymer.

Assignees

• Tosoh Corp

Inventors

• Kitagawa Takahiro
• Toyomasu Shinsuke
• Fujii Yasuyoshi

Classifications

• C08J7/0427

  with only one layer of a composition containing a polymer binder (with more layers C08J7/042) · CPC title

• G02B1/08

  made of polarising materials · CPC title

• C08J2333/04

  esters · CPC title

• G02F1/13363

  Birefringent elements, e.g. for optical compensation · CPC title

• G02F1/133634

  the refractive index Nz perpendicular to the element surface being different from in-plane refractive indices Nx and Ny, e.g. biaxial or with normal optical axis · CPC title