JPWO2012017775A1 - Urethane resin for retardation film and retardation film - Google Patents

Abstract

An object of the present invention is to provide a retardation film having high heat resistance, capable of performing uniform polarization conversion in a wide wavelength range, and having high retardation development property, and a resin used for the film. . A diisocyanate structural unit represented by the general formula I: [Chemical formula 1] [wherein X is as described in the specification], and a general formula II: [Chemical formula 2] [wherein R1 to R3, l , M, and n are as described in the specification], and the above-described problem is solved by a urethane film resin for a retardation film having a fluorene structural unit represented by: Can do.

Description

  The present invention relates to a retardation film urethane resin having a structural unit including an alicyclic portion and a structural unit including a fluorene portion, and a retardation film including the urethane resin.

  As a retardation film used for a liquid crystal display device or the like, a polycarbonate film has been used in the early stages of development (for example, Patent Document 1). However, since polycarbonate has a large photoelastic coefficient, it has been difficult to obtain a film having a uniform retardation.

  In reflective and transflective liquid crystal display devices used for mobile device applications and the like, there is a demand for a film with a small wavelength dispersion of retardation that can perform uniform polarization conversion in a wide wavelength range. However, since the polycarbonate film has large wavelength dispersion, it cannot perform uniform polarization conversion in a wide wavelength range.

  Therefore, a film obtained by adding a retardation adjusting agent to triacetyl cellulose has been put into practical use (for example, Patent Document 2). However, triacetyl cellulose has a problem that it is inferior in heat resistance.

In order to solve this problem, a film made of a cycloolefin resin has begun to be used as a retardation film having high heat resistance and low wavelength dispersion (for example, Patent Document 3). However, a film made of cycloolefin-based resin has low retardation development property, and the retardation cannot be increased. Therefore, in order to obtain a predetermined retardation film, a certain amount of thickness is required, and it is difficult to make the film thin.
Furthermore, in the organic EL display, there is a problem that the contrast is remarkably lowered when light from the outside of the display is reflected inside and escapes to the outside again, and a λ / 4 plate and a polarizing plate, which are a kind of retardation film, are used. By using a combined circularly polarizing plate on the outer surface of the display, measures are taken to block external light reflected inside the display. The chromatic dispersion of the λ / 4 plate used for this has an inverse chromatic dispersion property in which the phase difference is λ / 4 for all wavelengths λ in the visible light region, that is, the chromatic dispersion is opposite to that of polycarbonate or the like. is necessary.

Japanese Patent Laid-Open No. 5-113506 European Patent No. 0911656 JP-A-4-361230

  An object of this invention is to provide the retardation film used suitably in the reflection type and transflective liquid crystal display device used for a mobile device use etc. Therefore, it has high heat resistance, can perform uniform polarization conversion in a wide wavelength range, and can perform reverse wavelength dispersion polarization conversion with a smaller phase difference as the wavelength is shorter. It is an object to provide a high retardation film and a resin used for the film.

  As a result of intensive studies by the present inventors, it has been found that the above-mentioned problems can be solved by using a retardation film using a urethane resin having a structural unit containing an alicyclic part and a structural unit containing a fluorene part. .

  That is, the present invention includes the following.

[式中、Ｘはシクロアルキレン、アルキレンシクロアルキレン、シクロアルキレンアルキレンシクロアルキレン、アルキレンシクロアルキレンアルキレン、又はビシクロアルキレン（これらは、ハロゲン、Ｃ_１−６アルキル及びＣ_１−６アルコキシからなる群から選択される少なくとも１つの置換基で置換されていてもよい）である]
で表されるジイソシアネート構成単位と、
一般式ＩＩ：

[式中、
Ｒ^１は互いに独立してアルキレン、シクロアルキレン、アリーレン、又はアリーレンアルキレンであり；
ｌは０又は１であり；
Ｒ^２は互いに独立してハロゲン、Ｃ_１−６アルキル、又はＣ_１−６アルコキシであり；
ｍは０〜４の整数であり；
Ｒ^３は互いに独立してハロゲン、Ｃ_１−６アルキル、又はＣ_１−６アルコキシであり；
ｎは０〜４の整数である]
で表されるフルオレン構成単位と、
を有する位相差フィルム用ウレタン樹脂。
（２）Ｘがシクロへキシレン、Ｃ_１−３アルキレンシクロへキシレン、シクロへキシレンＣ_１−３アルキレンシクロへキシレン、Ｃ_１−３アルキレンシクロへキシレンＣ_１−３アルキレン、又はビシクロへキシレン（これらは、Ｃ_１−３アルキルで置換されていてもよい）であり、
Ｒ^１が互いに独立してＣ_１−３アルキレンであり、
ｌが１であり、
ｍ及びｎが０である、
（１）に記載の位相差フィルム用ウレタン樹脂。
（３）一般式Ｉで表されるジイソシアネート構成単位がジシクロへキシルメタン−４，４’−ジイソシアネート、イソホロンジイソシアネート、シクロへキシレンジイソシアネート、又は１，３−ビス（イソシアナトメチル）シクロヘキサンに由来する、（１）又は（２）に記載の位相差フィルム用ウレタン樹脂。
（４）一般式ＩＩで表されるフルオレン構成単位が９，９−ビス[４−（ヒドロキシＣ_１−３アルコキシ）フェニル]フルオレンに由来する、（１）〜（３）のいずれかに記載の位相差フィルム用ウレタン樹脂。
（５）一般式ＩＩＩ：

[式中、Ｙはシクロアルキレン、アルキレンシクロアルキレン、シクロアルキレンアルキレンシクロアルキレン、アルキレンシクロアルキレンアルキレン、又はビシクロアルキレン（これらは、ハロゲン、Ｃ_１−６アルキル及びＣ_１−６アルコキシからなる群から選択される少なくとも１つの置換基で置換されていてもよい）である]
で表されるジオール構成単位を更に有する、（１）〜（４）のいずれかに記載の位相差フィルム用ウレタン樹脂。
（６）Ｙがシクロへキシレン、Ｃ_１−３アルキレンシクロへキシレン、シクロへキシレンＣ_１−３アルキレンシクロへキシレン、Ｃ_１−３アルキレンシクロへキシレンＣ_１−３アルキレン、又はビシクロへキシレンである、（５）に記載の位相差フィルム用ウレタン樹脂。
（７）一般式ＩＩＩで表されるジオール構成単位が１，４−シクロへキサンジメタノール、１，４−シクロへキサンジオール、又は４，４’−ビシクロへキサンジオールに由来する、（５）又は（６）に記載の位相差フィルム用ウレタン樹脂。
（８）Ｘがシクロへキシレン（Ｃ_１−３アルキルで置換されていてもよい）であり、且つジイソシアネート構成単位における一方のイソシアネート部分の前記シクロヘキシレンに対する結合位置を１位とした場合に、他方のイソシアネート部分の結合位置が２位、３位、５位、又は６位であるか；
ＸがＣ_１−３アルキレンシクロへキシレン（Ｃ_１−３アルキルで置換されていてもよい）であり、且つジイソシアネート構成単位における一方のイソシアネート部分の前記シクロへキシレン部分に対する結合位置を１位とした場合に、他方のイソシアネート部分が結合する前記Ｃ_１−３アルキレン部分の結合位置が２位、３位、５位、又は６位であるか；又は
ＸがＣ_１−３アルキレンシクロへキシレンＣ_１−３アルキレン（Ｃ_１−３アルキルで置換されていてもよい）であり、且つジイソシアネート構成単位における一方のイソシアネート部分が結合する一方のＣ_１−３アルキレン部分の前記シクロへキシレン部分に対する結合位置を１位とした場合に、他方のイソシアネート部分が結合する他方のＣ_１−３アルキレン部分の結合位置が２位、３位、５位、又は６位である、（１）〜（７）のいずれかに記載の位相差フィルム用ウレタン樹脂。
（９）一般式Ｉで表されるジイソシアネート構成単位がイソホロンジイソシアネート、又は１，３−ビス（イソシアナトメチル）シクロヘキサンに由来する、（８）に記載の位相差フィルム用ウレタン樹脂。
（１０）一般式ＩＶ：

[式中、Ｘ’はＣ_１−１０アルキレン、又はアルキレンオキシアルキレン（全体で２〜１０個の炭素を有する）である]
で表されるジイソシアネート構成単位を更に有する、（８）又は（９）に記載の位相差フィルム用ウレタン樹脂。
（１１）一般式ＩＶで表されるジイソシアネート構成単位がヘキサメチレンジイソシアネートに由来する、（１０）に記載の位相差フィルム用ウレタン樹脂。
（１２）ガラス転移温度が１００〜２００℃である、（１）〜（１１）のいずれかに記載の位相差フィルム用ウレタン樹脂。
（１３）（１）〜（１２）のいずれかに記載の位相差フィルム用ウレタン樹脂を含む位相差フィルム。
（１４）以下の式：
Ｒｅ＝（ｎ_ｘ−ｎ_ｙ）×Ｄ
波長分散＝Ｒｅ（４４９）／Ｒｅ（５４８．７）
[式中、
ｎ_ｘは位相差フィルム面内における屈折率が最大となる遅相軸の方向の屈折率であり；
ｎ_ｙは前記遅相軸と直交する方向の屈折率であり；
Ｄは位相差フィルムの厚さ（ｎｍ）であり；
Ｒｅは面内位相差であって、Ｒｅ（４４９）は波長４４９ｎｍの光の面内位相差であり、Ｒｅ（５４８．７）は波長５４８．７ｎｍの光の面内位相差である]
により得られる波長分散が１．０２未満である、（１３）に記載の位相差フィルム。
本明細書は本願の優先権の基礎である日本国特許出願２０１０−１７５７３０号の明細書および／または図面に記載される内容を包含する。(1) General formula I:

Wherein X is cycloalkylene, alkylene cycloalkylene, cycloalkylene alkylene cycloalkylene, alkylene cycloalkylene alkylene, or bicycloalkylene (which are selected from the group consisting of halogen, C _1-6 alkyl and C _1-6 alkoxy Optionally substituted with at least one substituent)]
A diisocyanate structural unit represented by:
Formula II:

[Where
R ¹ is independently of each other alkylene, cycloalkylene, arylene, or arylene alkylene;
l is 0 or 1;
R ² is independently of each other halogen, C _1-6 alkyl, or C _1-6 alkoxy;
m is an integer from 0 to 4;
R ³ is independently of each other halogen, C _1-6 alkyl, or C _1-6 alkoxy;
n is an integer from 0 to 4]
A fluorene constituent unit represented by:
A urethane resin for retardation film.
(2) X is cyclohexylene, C _1-3 alkylenecyclohexylene, cyclohexylene C _1-3 alkylenecyclohexylene, C _1-3 alkylenecyclohexylene C _1-3 alkylene, or bicyclohexylene (these _May be substituted with C _1-3 alkyl),
R ¹ is independently of each other C _1-3 alkylene,
l is 1,
m and n are 0,
(1) Urethane resin for retardation films as described in (1).
(3) The diisocyanate structural unit represented by the general formula I is derived from dicyclohexylmethane-4,4′-diisocyanate, isophorone diisocyanate, cyclohexylene diisocyanate, or 1,3-bis (isocyanatomethyl) cyclohexane. The urethane resin for retardation films as described in 1) or (2).
(4) The fluorene structural unit represented by the general formula II is derived from 9,9-bis [4- (hydroxyC _1-3 alkoxy) phenyl] fluorene, according to any one of (1) to (3) Urethane resin for retardation film.
(5) General formula III:

Wherein Y is cycloalkylene, alkylene cycloalkylene, cycloalkylene alkylene cycloalkylene, alkylene cycloalkylene alkylene, or bicycloalkylene (which are selected from the group consisting of halogen, C _1-6 alkyl and C _1-6 alkoxy Optionally substituted with at least one substituent)]
The urethane resin for retardation films according to any one of (1) to (4), further having a diol structural unit represented by:
(6) Y is cyclohexylene, C _1-3 alkylenecyclohexylene, cyclohexylene C _1-3 alkylenecyclohexylene, C _1-3 alkylenecyclohexylene C _1-3 alkylene, or bicyclohexylene. Urethane resin for retardation films as described in (5).
(7) The diol structural unit represented by the general formula III is derived from 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, or 4,4′-bicyclohexanediol, (5) Or the urethane resin for retardation films as described in (6).
(8) When X is cyclohexylene (which may be substituted with _C1-3 alkyl) and the bonding position of one isocyanate moiety in the diisocyanate structural unit to the cyclohexylene is the 1st position, the other Whether the bonding position of the isocyanate moiety is 2-position, 3-position, 5-position, or 6-position;
X is C _1-3 alkylenecyclohexylene (which may be substituted with C _1-3 alkyl), and the bonding position of one isocyanate moiety in the diisocyanate structural unit to the cyclohexylene moiety is defined as the first position In some cases, the bonding position of the C _1-3 alkylene moiety to which the other isocyanate moiety is bonded is 2, 3, 5, or 6; or X is C _1-3 alkylenecyclohexylene C ₁ A bonding position of one C _1-3 alkylene moiety to which the one isocyanate moiety in the diisocyanate structural unit is bonded to the cyclohexylene moiety is a _-3 alkylene (which may be substituted with C _1-3 alkyl) when the 1-position, coupling position of the other C _1-3 alkylene moiety is other isocyanate moiety binds Position 2, 3, 5, or 6-position, (1) to the phase difference film urethane resin according to any one of (7).
(9) The urethane resin for retardation film according to (8), wherein the diisocyanate structural unit represented by the general formula I is derived from isophorone diisocyanate or 1,3-bis (isocyanatomethyl) cyclohexane.
(10) General formula IV:

[ _Wherein X ′ is C _1-10 alkylene or alkyleneoxyalkylene (having 2 to 10 carbons in total)]
The urethane resin for retardation films according to (8) or (9), further having a diisocyanate structural unit represented by:
(11) The urethane resin for retardation film according to (10), wherein the diisocyanate structural unit represented by the general formula IV is derived from hexamethylene diisocyanate.
(12) The urethane resin for retardation film according to any one of (1) to (11), wherein the glass transition temperature is 100 to 200 ° C.
(13) A retardation film comprising the urethane resin for retardation film according to any one of (1) to (12).
(14) The following formula:
_{Re = (n x -n y)} × D
Chromatic dispersion = Re (449) / Re (548.7)
[Where
_nx is the refractive index in the direction of the slow axis where the refractive index in the retardation film plane is maximum;
n _y is a refractive index in the direction perpendicular to the slow axis;
D is the thickness of the retardation film (nm);
Re is an in-plane phase difference, Re (449) is an in-plane phase difference of light having a wavelength of 449 nm, and Re (548.7) is an in-plane phase difference of light having a wavelength of 548.7 nm]
The retardation film according to (13), wherein the chromatic dispersion obtained by the method is less than 1.02.
This specification includes the contents described in the specification and / or drawings of Japanese Patent Application No. 2010-175730, which is the basis of the priority of the present application.

  ADVANTAGE OF THE INVENTION According to this invention, the retardation film of the reflection type and transflective liquid crystal display device used suitably for a mobile device use etc. can be provided. More specifically, a retardation film having high heat resistance, capable of performing uniform polarization conversion in a wide wavelength range, and having high retardation development, and a resin used for the film are provided. can do.

The wavelength dispersion characteristics (R / R0) of the urethane resin films and broadband λ / 4 plates of Examples 4 to 8 are shown.

Hereinafter, the present invention will be described in detail.
In the present invention, “alkylene” means a divalent group formed by losing two hydrogen atoms from a carbon atom of an alkane, and is generally represented by —C _n H _2n — (n is a positive integer). Is done. Alkylene may be linear or branched. In addition, so-called alkylidene generated by losing two hydrogen atoms from the same carbon atom is also included in the alkylene in the present invention.

As alkylene in this invention, _C1-6 alkylene is preferable and _C1-3 alkylene is especially preferable. For example, methylene, ethylene, propylene, butylene, pentylene, hexylene and the like can be mentioned.

In the present invention, “cycloalkylene” means a divalent group formed by losing two hydrogen atoms from a carbon atom of a cycloalkane. In general, —C _m H _2m-2 — (m is a positive number of 3 or more. It is an integer and represents a ring. So-called cycloalkylidene formed by losing two hydrogen atoms from the same carbon atom is also included in the cycloalkylene in the present invention.

As the cycloalkylene in the present invention, C _3-10 cycloalkylene is preferable, and C _5-8 alkylene is particularly preferable. For example, cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, cycloheptylene, cyclooctylene, and the like can be given.

The “alkylenecycloalkylene” in the present invention means a divalent group formed by losing one hydrogen atom from each carbon atom of the alkyl part of the alkylcycloalkane and from the carbon atom of the cycloalkane part. _{C n H 2n -C m H 2m} -2 - (n is a positive integer; m is a positive integer of 3 or more, to form a ring) represented by. The alkyl moiety may be linear or branched.

As the alkylene cycloalkylene in the present invention, C _1-6 alkylene C _3-10 cycloalkylene is preferable, and C _1-3 alkylene C _5-8 cycloalkylene is particularly preferable. For example, methylenecyclopentylene, methylenecyclohexylene, methylenecycloheptylene, ethylenecyclopentylene, ethylenecyclohexylene, ethylenecycloheptylene, propylenecyclopentylene, propylenecyclohexylene, propylenecycloheptylene, etc. Can do.

The “cycloalkylenealkylenecycloalkylene” in the present invention means a divalent group formed by losing one hydrogen atom from each carbon atom of two cycloalkyl moieties of a dicycloalkylalkane. _m H _2m-2 —C _n H _2n —C _m H _2m-2 — (n is a positive integer; m is a positive integer of 3 or more and forms a ring). The alkane moiety may be linear or branched.

As the cycloalkylene alkylene cycloalkylene in the present invention, C _3-10 cycloalkylene C _1-6 alkylene C _3-10 cycloalkylene is preferable, and C _5-8 cycloalkylene C _1-3 alkylene C _5-8 cycloalkylene is particularly preferable. preferable. For example, cyclopentylenemethylenecyclopentylene, cyclohexylenemethylenecyclohexylene, cycloheptylenemethylenecycloheptylene, cyclopentyleneethylenecyclopentylene, cyclohexyleneethylenecyclohexylene, cycloheptyleneethylenecyclohexane Examples include butylene, cyclopentylenepropylenecyclopentylene, cyclohexylenepropylenecyclohexylene, and cycloheptylenepropylenecycloheptylene.

The “alkylenecycloalkylenealkylene” in the present invention means a divalent group formed by losing one hydrogen atom from each carbon atom of two alkyl portions of a dialkylcycloalkane, and generally is represented by —C _n H _{2n -C m H 2m-2 -C n} H 2n - (n is a positive integer; m is a positive integer of 3 or more, to form a ring) represented by. The alkyl moiety may be linear or branched.

As the alkylene cycloalkylene alkylene in the present invention, C _1-6 alkylene C _3-10 cycloalkylene C _1-6 alkylene is preferable, and C _1-3 alkylene C _5-8 cycloalkylene C _1-3 alkylene is particularly preferable. For example, methylenecyclopentylenemethylene, methylenecyclohexylenemethylene, methylenecycloheptylenemethylene, ethylenecyclopentyleneethylene, ethylenecyclohexyleneethylene, ethylenecycloheptyleneethylene, propylenecyclopentylenepropylene, propylenecyclohexylene Examples include propylene and propylene cycloheptylene propylene.

The “bicycloalkylene” in the present invention means a divalent group formed by losing one hydrogen atom from each carbon atom of the two cycloalkane portions of the bicycloalkane, and in general, —C _m H _{2m−2 -C m H 2m-2 - (} m is a positive integer of 3 or more, to form a ring) represented by.

As bicycloalkylene in this invention, _C3-10 cycloalkylene _C3-10 cycloalkylene is preferable and _C5-8 cycloalkylene _C5-8 cycloalkylene is especially preferable. For example, cyclopentylene cyclopentylene, cyclohexylene cyclohexylene, cycloheptylene cycloheptylene and the like can be mentioned.

  The “arylene” in the present invention means a divalent group formed by losing two hydrogen atoms from a carbon atom of an aromatic hydrocarbon. Arylene may be a single ring or a condensed ring.

  Examples of the arylene in the present invention include phenylene, naphthylene, biphenylylene and the like.

  The “arylene alkylene” in the present invention means a divalent group formed by losing one hydrogen atom from each of the carbon atom of the alkyl part and the carbon atom of the arene part. The alkyl moiety may be linear or branched, and the arene moiety may be a single ring or a condensed ring.

As the arylene alkylene in the present invention, arylene C _1-6 alkylene is preferable, and arylene C _1-3 alkylene is particularly preferable. Examples include phenylenemethylene, phenyleneethylene, naphthylenemethylene, naphthyleneethylene, biphenylylenemethylene, biphenylyleneethylene, and the like.

[式中、Ｘはシクロアルキレン、アルキレンシクロアルキレン、シクロアルキレンアルキレンシクロアルキレン、アルキレンシクロアルキレンアルキレン、又はビシクロアルキレン（これらは、ハロゲン、Ｃ_１−６アルキル及びＣ_１−６アルコキシからなる群から選択される少なくとも１つの置換基で置換されていてもよい）である]
で表されるジイソシアネート構成単位と、
一般式ＩＩ：

[式中、
Ｒ^１は互いに独立してアルキレン、シクロアルキレン、アリーレン、又はアリーレンアルキレンであり；
ｌは０又は１であり；
Ｒ^２は互いに独立してハロゲン、Ｃ_１−６アルキル、又はＣ_１−６アルコキシであり；
ｍは０〜４の整数であり；
Ｒ^３は互いに独立してハロゲン、Ｃ_１−６アルキル、又はＣ_１−６アルコキシであり；
ｎは０〜４の整数である]
で表されるフルオレン構成単位
から構成される。1. Urethane resin for retardation film The urethane resin for retardation film of the present invention has the general formula I:

Wherein X is cycloalkylene, alkylene cycloalkylene, cycloalkylene alkylene cycloalkylene, alkylene cycloalkylene alkylene, or bicycloalkylene (which are selected from the group consisting of halogen, C _1-6 alkyl and C _1-6 alkoxy Optionally substituted with at least one substituent)]
A diisocyanate structural unit represented by:
Formula II:

[Where
R ¹ is independently of each other alkylene, cycloalkylene, arylene, or arylene alkylene;
l is 0 or 1;
R ² is independently of each other halogen, C _1-6 alkyl, or C _1-6 alkoxy;
m is an integer from 0 to 4;
R ³ is independently of each other halogen, C _1-6 alkyl, or C _1-6 alkoxy;
n is an integer from 0 to 4]
It is comprised from the fluorene structural unit represented by these.

  In addition to the diisocyanate structural unit represented by the general formula I and the fluorene structural unit represented by the general formula II, the urethane resin for retardation film of the present invention has the general formula III:

[式中、Ｙはシクロアルキレン、アルキレンシクロアルキレン、シクロアルキレンアルキレンシクロアルキレン、アルキレンシクロアルキレンアルキレン、又はビシクロアルキレン（これらは、ハロゲン、Ｃ_１−６アルキル及びＣ_１−６アルコキシからなる群から選択される少なくとも１つの置換基で置換されていてもよい）である]
で表されるジオール構成単位を更に有することができる。

Wherein Y is cycloalkylene, alkylene cycloalkylene, cycloalkylene alkylene cycloalkylene, alkylene cycloalkylene alkylene, or bicycloalkylene (which are selected from the group consisting of halogen, C _1-6 alkyl and C _1-6 alkoxy Optionally substituted with at least one substituent)]
The diol structural unit represented by these can further be included.

In the case of having the diol constituent unit represented by the general formula III, the ratio of the fluorene unit to the total of the fluorene constituent unit and the diol constituent unit is the following formula for the retardation film produced from the urethane resin:
_{Re = (n x -n y)} × D
Chromatic dispersion = Re (449) / Re (548.7)
[Where
_nx is the refractive index in the direction of the slow axis where the refractive index in the retardation film plane is maximum;
n _y is a refractive index in the direction perpendicular to the slow axis;
D is the thickness of the retardation film (nm);
Re is an in-plane phase difference, Re (449) is an in-plane phase difference of light having a wavelength of 449 nm, and Re (548.7) is an in-plane phase difference of light having a wavelength of 548.7 nm]
Although it will not specifically limit if it is a ratio from which the chromatic dispersion obtained by this is less than 1.02, Especially preferably, it is 30 mol% or more. Moreover, the urethane resin may have other arbitrary structural units in the range which does not impair the effect of this invention.

  Although there is no restriction | limiting in particular in the weight average molecular weight (Mw) of the urethane resin of this invention, It is preferable that it is 200,000-5,000, It is especially preferable that it is 100,000-10,000, 50,000- Most preferred is 20,000. The weight average molecular weight can be measured using gel permeation chromatography (GPC).

  The glass transition temperature (Tg) of the urethane resin of the present invention is preferably 100 to 200 ° C, and particularly preferably 120 to 180 ° C. The glass transition temperature can be measured by differential scanning calorimetry (DSC). When the glass transition temperature is less than 100 ° C., problems such as a change in retardation value occur when a retardation film produced from a urethane resin is stored at a high temperature. On the other hand, when the glass transition temperature exceeds 200 ° C., processing such as stretching becomes difficult and it becomes difficult to produce a retardation film.

2. Diisocyanate Structural Unit In one embodiment of the present invention, X in the diisocyanate structural unit represented by Formula I is cyclohexylene, C _1-3 alkylenecyclohexylene, cyclohexylene C _1-3 alkylenecyclohexylene, C _1-3 alkylene cyclohexylene C _1-3 alkylene, or bicyclohexylene, which are substituted with at least one substituent selected from the group consisting of halogen, C _1-6 alkyl and C _1-6 alkoxy May be).

In preferred embodiments of the invention, X is cyclohexylene, methylenecyclohexylene, cyclohexylenemethylenecyclohexylene, methylenecyclohexylenemethylene, or bicyclohexylene, which are substituted with _C1-3 alkyl. May be).

[式中、Ｘ’はＣ_１−１０アルキレン、又はアルキレンオキシアルキレン（全体で２〜１０個の炭素を有する）である]
で表される別のジイソシアネート構成単位を共重合形態で含有することが好ましい。これにより、延伸などの成形加工がより行いやすいＴｇまで下げることができる。
本発明の一実施形態において、一般式ＩＶで表されるジイソシアネート構成単位におけるＸ’はＣ_４−８アルキレン、又はアルキレンオキシアルキレン（全体で４〜８個の炭素を有する）であり、好ましくはＣ_４−８アルキレンであり、特に好ましくはヘキシレンである。In a particularly preferred embodiment of the present invention, X is xylene C _1-3 alkylene (which cyclohexylene hexylene methylenecyclopropane, cyclohexylene, C _1-3 cyclohexylene alkylene cycloalkyl, or to C _1-3 alkylene cyclohexylene, _Optionally substituted with C _1-3 alkyl). In particular, in order to obtain a reverse wavelength dispersive urethane film for retardation film, X is cyclohexylene (which may be substituted with _C1-3 alkyl), and one isocyanate moiety in the diisocyanate constituent unit Is the first bonding position with respect to cyclohexylene, the bonding position of the other isocyanate moiety is 2, 3, 5, or 6; X is C _1-3 alkylenecyclohexylene ( C _1-3 alkyl may be substituted), and when the bonding position of one isocyanate moiety to the cyclohexylene moiety in the diisocyanate structural unit is the first position, the other isocyanate moiety is bonded C _1-3 bond position 2-position of the alkylene moiety, 3, 5, or 6; or X is _{C 1-3} Al Xylene C _1-3 alkylene to Renshikuro a (C _1-3 alkyl optionally substituted by), and xylene to said cyclo one C _1-3 alkylene moiety of which one isocyanate moiety in the diisocyanate structural unit is bound When the bonding position with respect to the moiety is 1-position, the bonding position of the other C _1-3 alkylene moiety to which the other isocyanate moiety is bonded is preferably the 2-position, 3-position, 5-position, or 6-position. In particular, it is preferable that the two isocyanate moieties are directly or indirectly bonded to cyclohexylene in the 1,3-position.
Furthermore, the urethane resin of the present invention has the general formula IV:

[ _Wherein X ′ is C _1-10 alkylene or alkyleneoxyalkylene (having 2 to 10 carbons in total)]
It is preferable to contain the another diisocyanate structural unit represented by these by copolymerization form. Thereby, it can be lowered to Tg at which molding such as stretching is easier.
In one embodiment of the present invention, X ′ in the diisocyanate structural unit represented by the general formula IV is C _4-8 alkylene or alkyleneoxyalkylene (having 4 to 8 carbons in total), preferably C _4-8 alkylene, particularly preferably hexylene.

  Examples of the diisocyanate compound for producing the urethane resin having the diisocyanate structural unit represented by the general formula I include dicyclohexylmethane-4,4′-diisocyanate, isophorone diisocyanate, cyclohexylene diisocyanate, and 1,3-bis. (Isocyanatomethyl) cyclohexane and the like. Preferably, dicyclohexylmethane-4,4'-diisocyanate is used, and isophorone diisocyanate and 1,3-bis (isocyanatomethyl) cyclohexane are used to obtain a reverse wavelength dispersible urethane resin. These diisocyanate compounds may be used alone or in combination of two or more. Moreover, hexamethylene diisocyanate is mentioned as a preferable example of the compound for forming the diisocyanate structural unit represented by the general formula IV for facilitating forming processing such as stretching.

3. Fluorene Structural Unit In one embodiment of the present invention, R ¹ in the fluorene structural unit represented by the general formula II is independently C _1-3 alkylene, and 1 is 1.

In a preferred embodiment of the invention, R ¹ is both ethylene and l is 1.

In one embodiment of the present invention, R ² and R ³ in the fluorene structural unit are each independently C _1-3 alkyl, and m and n are each independently an integer of 0-2.

  In a preferred embodiment of the invention, m and n are both 0.

Examples of the fluorene compound for producing the urethane resin having the fluorene structural unit include 9,9-bis [4- (hydroxyC _1-3 alkoxy) phenyl] fluorene, and preferably 9,9-bis. [4- (2-hydroxyethoxy) phenyl] fluorene. These fluorene compounds may be used alone or in combination of two or more.

4). Diol Constituent Unit In one embodiment of the present invention, Y in the diol constituent unit represented by the general formula III is cyclohexylene, C _1-3 alkylenecyclohexylene, cyclohexylene C _1-3 alkylenecyclohexylene, C _1-3 alkylene cyclohexylene C _1-3 alkylene, or bicyclohexylene, which are substituted with at least one substituent selected from the group consisting of halogen, C _1-6 alkyl and C _1-6 alkoxy May be).

In preferred embodiments of the invention, Y is cyclohexylene, methylenecyclohexylene, cyclohexylenemethylenecyclohexylene, methylenecyclohexylenemethylene, or bicyclohexylene, which are substituted with _C1-3 alkyl. May be).

  In a particularly preferred embodiment of the invention, Y is methylenecyclohexylenemethylene.

  Examples of the diol compound for producing the urethane resin having the diol structural unit include 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, or 4,4′-bicyclohexanediol. Preferably, 1,4-cyclohexane dimethanol is mentioned. These diol compounds may be used alone or in combination of two or more.

5. Retardation film The retardation film of this invention can be manufactured from the said urethane resin. The retardation film may contain other optional components as long as the effects of the present invention are not impaired.

  The production method of the retardation film is not particularly limited, and various known methods can be used. For example, after a urethane resin is dissolved in a solvent and coated on a support, a method of drying and stretching, a method of supplying a urethane resin to an extruder, extruding into a film form from a T die, and further stretching be able to.

  The in-plane retardation (Re) of the retardation film of the present invention is preferably 100 to 2000 nm and particularly preferably 300 to 1500 nm in terms of a thickness of 100 μm. When the in-plane retardation is less than 100 nm, the retardation film must be thickened, which goes against the reduction in size and weight of mobile devices. On the other hand, if the in-plane retardation exceeds 2000 nm, the thickness of the film becomes too thin and processing becomes difficult.

The in-plane phase difference is given by the following formula:
_{Re = (n x -n y)} × D
[Where
_nx is the refractive index in the direction of the slow axis where the refractive index in the retardation film plane is maximum;
n _y is a refractive index in the direction perpendicular to the slow axis;
D is the thickness of the retardation film (nm)]
Can be obtained from

  As in the in-plane retardation, the thickness direction retardation of the retardation film of the present invention is preferably 100 to 2000 nm, particularly preferably 300 to 1500 nm, in terms of a thickness of 100 μm.

The thickness direction retardation is calculated by the following formula:
Thickness direction retardation (Re ′) = (n _x −n _z ) × D
[Where
_nx is the refractive index in the direction of the slow axis where the refractive index in the retardation film plane is maximum;
n _z is the refractive index in the thickness direction of the retardation film;
D is the thickness of the retardation film (nm)]
Can be obtained from

  The chromatic dispersion of the retardation film of the present invention is preferably less than 1.02, more preferably less than 0.92 and less than 1.02, in order to perform uniform polarization conversion in a wide wavelength range. Preferably they are 0.95 or more and 1.01 or less.

Chromatic dispersion is the following formula:
Chromatic dispersion = Re (449) / Re (548.7)
[Where
Re (449) is the in-plane phase difference of light with a wavelength of 449 nm;
Re (548.7) is the in-plane phase difference of light with a wavelength of 548.7 nm]
Can be obtained from
Further, in order to obtain a reverse wavelength dispersive film, the wavelength dispersion of the retardation film is preferably from 0.7 to 0.95, and particularly preferably close to 0.81.

  Since the retardation film of the present invention has high retardation, the film thickness can be reduced. For example, the film thickness is preferably 5 to 50 μm, and particularly preferably 10 to 30 μm.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, the technical scope of this invention is not limited by this.

Evaluation and analysis method The evaluation and analysis method used in this example is as follows.
(1) Heat resistance of resin It evaluated by the glass transition temperature (Tg) measured when it heated up at 20 degree-C / min by differential scanning calorimetry (DSC).
(2) Weight average molecular weight (Mw)
It measured using gel permeation chromatography (GPC).
(3) Optical characteristics of solvent cast film The resin was dissolved in a solvent and applied to a fluororesin coated plate. The film peeled after drying was uniaxially stretched twice at a glass transition temperature of 10 to 25 ° C., and then the following optical properties were evaluated.

(I) Phase difference The in-plane and thickness direction phase differences with respect to light having a wavelength of 589.3 nm were measured with an ellipsometer (KOBLA WPRXY2020, manufactured by Oji Scientific Instruments). The phase difference was converted to a value at a film thickness of 100 μm.

(Ii) Wavelength dispersion In-plane phase difference between light having a wavelength of 449 nm and light of 548.7 nm [R (449) and R (548.7)] using an ellipsometer (KOBLA WPRXY2020, manufactured by Oji Scientific Instruments). And chromatic dispersion [R (449) / R (548.7)] was determined.

Example 1
9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene (23.9 parts by weight) and 1,4-cyclohexanedimethanol (18.4 parts by weight) were added to the reaction vessel, and dimethylformamide ( 60 parts by weight) was added and dissolved. Then, dicyclohexylmethane-4,4′-diisocyanate (47.7 parts by weight) was slowly added while stirring the solution. After completion of the addition, the reaction was carried out at 130 ° C. for 11 hours, then heated to 220 ° C. and the solvent was removed under reduced pressure.
The heat resistance, molecular weight, and optical properties of the obtained resin were evaluated, and the results are shown in Table 1.

Examples 2 and 3
Example 1 except that 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene, 1,4-cyclohexanedimethanol, and dicyclohexylmethane-4,4′-diisocyanate were changed as shown in Table 1. A resin was prepared in the same manner as described above.
The heat resistance, molecular weight, and optical properties of the obtained resin were evaluated, and the results are shown in Table 1.

Comparative Example 1
1,4-Cyclohexanedimethanol (31.9 parts by weight) was added to the reaction vessel, and dimethylformamide (60 parts by weight) was added and dissolved. Next, dicyclohexylmethane-4,4′-diisocyanate (58.1 parts by weight) was slowly added while stirring the solution. After completion of the addition, the reaction was carried out at 130 ° C. for 4 hours, then heated to 220 ° C. and the solvent was removed under reduced pressure.
The heat resistance, molecular weight, and optical properties of the obtained resin were evaluated, and the results are shown in Table 1.

Comparative Example 2
A film made of cycloolefin resin (Zeonor (registered trademark) film manufactured by Nippon Zeon Co., Ltd.) was uniaxially stretched in the same manner as in Example 1 to evaluate optical properties.

Comparative Example 3
A polycarbonate resin (manufactured by Mitsubishi Engineering Plastics, product number H4000) was supplied to an extruder, and the film produced by extrusion from a T die at 280 ° C. was uniaxially stretched in the same manner as in Example 1 to evaluate optical properties.

  In the urethane resin (Comparative Example 1) and polycarbonate film (Comparative Example 3) that do not have a fluorene skeleton, the wavelength dispersion of the film is as large as 1.02 and 1.07, respectively, so that uniform polarization conversion is performed in a wide wavelength range. It is difficult.

  Further, in the film made of cycloolefin resin (Comparative Example 2), the wavelength dispersion of the film is as small as 1.00, but it is difficult to obtain a thin retardation film because the retardation at the time of double stretching is small. .

実施例４〜８のウレタン樹脂はフィルムの波長分散が０．９を下回り、逆波長分散性を示した。更に、全ての波長λで位相差がλ／４となる広帯域λ／４板の波長分散[Ｒｅ（４４９）／Ｒｅ（５４８．７）]は０．８１であり、実施例５〜８は広帯域λ／４板の波長分散と同等かそれを下回る波長分散特性を示した。
（４）高倍率延伸フィルムの位相差
樹脂を溶媒に溶解し、フッ素樹脂コート板に塗布した。乾燥後に剥がしたフィルムをガラス転移温度＋１０〜２５℃で３倍に一軸延伸した後、上記評価分析方法の（３）（ｉ）と同様に位相差を評価した。
その結果、実施例４及び５のウレタン樹脂の高倍率延伸フィルムは、それぞれ、３１０ｎｍ、２３２ｎｍと高い位相差を示した。すなわち、広帯域λ／４板（波長５８９．３ｎｍでの位相差は１４７．３ｎｍ）とするための厚さはそれぞれ、４８μｍ、６３μｍとなり、これはモバイル機器に搭載するのに十分な薄さであった。
本明細書で引用した全ての刊行物、特許、及び特許出願をそのまま参考として本明細書に取り入れるものとする。On the other hand, the urethane resins of the present invention (Examples 1 to 3) have high heat resistance with a glass transition temperature of 100 ° C. or higher, the wavelength dispersion of the film is less than 1.02, and further, when stretched twice. The phase difference is large. Therefore, a thin retardation film capable of uniform polarization conversion in a wide wavelength range can be obtained.
Example 4
9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene (50.7 parts by weight) and 1,4-cyclohexanedimethanol (7.1 parts by weight) were added to the reaction vessel, and dimethylformamide ( 60 parts by weight) was added and dissolved. Then, isophorone diisocyanate (18.3 parts by weight) and hexamethylene diisocyanate (13.9 parts by weight) were slowly added while stirring the solution. After completion of the addition, the reaction was carried out at 130 ° C. for 16 hours, then heated to 160 ° C. and the solvent was removed under reduced pressure.
Examples 5-8
Resin as in Example 4 except that 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene, 1,4-cyclohexanedimethanol, isophorone diisocyanate, and hexamethylene diisocyanate were changed as shown in Table 2. It was created.
The heat resistance, molecular weight, and optical properties of the obtained resin were evaluated, and the results are shown in Table 2. Further, the phase difference R for the light having a wavelength of 449 nm to 749.4 nm and the phase difference R0 for the light having a wavelength of 589.3 nm were measured, and the chromatic dispersion characteristic (R / R0) was obtained. The results are shown in FIG.

In the urethane resins of Examples 4 to 8, the wavelength dispersion of the film was less than 0.9, and the reverse wavelength dispersion was exhibited. Further, the wavelength dispersion [Re (449) / Re (548.7)] of the broadband λ / 4 plate having a phase difference of λ / 4 at all wavelengths λ is 0.81, and Examples 5 to 8 are broadband. The wavelength dispersion characteristic was equal to or less than the wavelength dispersion of the λ / 4 plate.
(4) Retardation of high magnification stretched film The resin was dissolved in a solvent and applied to a fluororesin coated plate. The film peeled off after drying was uniaxially stretched 3 times at a glass transition temperature of +10 to 25 ° C., and then the phase difference was evaluated in the same manner as in the evaluation analysis method (3) (i).
As a result, the urethane resin high-magnification stretched films of Examples 4 and 5 exhibited high retardations of 310 nm and 232 nm, respectively. In other words, the thicknesses for the broadband λ / 4 plate (the phase difference at a wavelength of 589.3 nm is 147.3 nm) are 48 μm and 63 μm, respectively, which are thin enough to be mounted on a mobile device. It was.
All publications, patents, and patent applications cited herein are incorporated herein by reference in their entirety.

Claims (14)

Formula I:

Wherein X is cycloalkylene, alkylene cycloalkylene, cycloalkylene alkylene cycloalkylene, alkylene cycloalkylene alkylene, or bicycloalkylene (which are selected from the group consisting of halogen, C _1-6 alkyl and C _1-6 alkoxy Optionally substituted with at least one substituent)]
A diisocyanate structural unit represented by:
Formula II:

[Where
R ¹ is independently of each other alkylene, cycloalkylene, arylene, or arylene alkylene;
l is 0 or 1;
R ² is independently of each other halogen, C _1-6 alkyl, or C _1-6 alkoxy;
m is an integer from 0 to 4;
R ³ is independently of each other halogen, C _1-6 alkyl, or C _1-6 alkoxy;
n is an integer from 0 to 4]
A fluorene constituent unit represented by:
A urethane resin for retardation film. X is cyclohexylene, C _1-3 alkylenecyclohexylene, cyclohexylene C _1-3 alkylenecyclohexylene, C _1-3 alkylenecyclohexylene C _1-3 alkylene, or bicyclohexylene (these are C _Optionally substituted with _1-3 alkyl),
R ¹ is independently of each other C _1-3 alkylene,
l is 1,
m and n are 0,
The urethane resin for retardation films according to claim 1.   The diisocyanate structural unit represented by the general formula I is derived from dicyclohexylmethane-4,4'-diisocyanate, isophorone diisocyanate, cyclohexylene diisocyanate, or 1,3-bis (isocyanatomethyl) cyclohexane. 2. Urethane resin for retardation film according to 2. The urethane for retardation films according to claim 1, wherein the fluorene structural unit represented by the general formula II is derived from 9,9-bis [4- (hydroxyC _1-3 alkoxy) phenyl] fluorene. resin. Formula III:

Wherein Y is cycloalkylene, alkylene cycloalkylene, cycloalkylene alkylene cycloalkylene, alkylene cycloalkylene alkylene, or bicycloalkylene (which are selected from the group consisting of halogen, C _1-6 alkyl and C _1-6 alkoxy Optionally substituted with at least one substituent)]
The urethane resin for retardation films according to claim 1, further comprising a diol structural unit represented by: Y is cyclohexylene, C _1-3 alkylenecyclohexylene, cyclohexylene C _1-3 alkylenecyclohexylene, C _1-3 alkylenecyclohexylene C _1-3 alkylene, or bicyclohexylene. 5. Urethane resin for retardation film of 5.   The diol structural unit represented by the general formula III is derived from 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, or 4,4′-bicyclohexanediol. The urethane resin for retardation films as described. When X is cyclohexylene (which may be substituted with _C1-3 alkyl) and the bonding position of one isocyanate moiety in the diisocyanate structural unit to the cyclohexylene is the 1st position, the other isocyanate moiety Whether the bonding position is at the 2-position, 3-position, 5-position, or 6-position;
X is C _1-3 alkylenecyclohexylene (which may be substituted with C _1-3 alkyl), and the bonding position of one isocyanate moiety in the diisocyanate structural unit to the cyclohexylene moiety is defined as the first position In some cases, the bonding position of the C _1-3 alkylene moiety to which the other isocyanate moiety is bonded is 2, 3, 5, or 6; or X is C _1-3 alkylenecyclohexylene C ₁ A bonding position of one C _1-3 alkylene moiety to which the one isocyanate moiety in the diisocyanate structural unit is bonded to the cyclohexylene moiety is a _-3 alkylene (which may be substituted with C _1-3 alkyl) when the 1-position, coupling position of the other C _1-3 alkylene moiety is other isocyanate moiety binds Position 2, 3, 5, or 6-position, the phase difference film urethane resin according to claim 1.   The urethane resin for retardation films according to claim 8, wherein the diisocyanate structural unit represented by the general formula I is derived from isophorone diisocyanate or 1,3-bis (isocyanatomethyl) cyclohexane. Formula IV:

[ _Wherein X ′ is C _1-10 alkylene or alkyleneoxyalkylene (having 2 to 10 carbons in total)]
The urethane resin for retardation films of Claim 8 or 9 which has further the diisocyanate structural unit represented by these.   The urethane resin for retardation films according to claim 10, wherein the diisocyanate structural unit represented by the general formula IV is derived from hexamethylene diisocyanate.   The urethane resin for retardation films according to claim 1, wherein the glass transition temperature is 100 to 200 ° C.   The retardation film containing the urethane resin for retardation films in any one of Claims 1-12. The following formula:
_{Re = (n x -n y)} × D
Chromatic dispersion = Re (449) / Re (548.7)
[Where
_nx is the refractive index in the direction of the slow axis where the refractive index in the retardation film plane is maximum;
n _y is a refractive index in the direction perpendicular to the slow axis;
D is the thickness of the retardation film (nm);
Re is an in-plane phase difference, Re (449) is an in-plane phase difference of light having a wavelength of 449 nm, and Re (548.7) is an in-plane phase difference of light having a wavelength of 548.7 nm]
The retardation film of Claim 13 whose wavelength dispersion obtained by is less than 1.02.

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