JPWO2007010830A1 - Cyclic olefin ring-opening copolymer, use thereof, and method for producing retardation plate containing the copolymer - Google Patents

Abstract

The cyclic olefin-based ring-opening copolymer of the present invention has a structural unit derived from a cyclic olefin having a polar group and a hydrocarbon group, and tricyclo [4.3.0.12,5] which may have a substituent. A structural unit derived from deca-3-ene and the like, and a structural unit derived from a cyclic olefin having no polar group. According to the present invention, it is excellent in heat resistance and optical properties, can form a film or sheet suitably, and can be stretched without causing problems such as cloudiness even at a relatively low temperature near Tg. An olefin copolymer and a film or sheet containing the cyclic olefin copolymer, which is excellent in optical properties and heat resistance and suitable for stretching at a relatively low temperature, can be provided. Furthermore, according to the present invention, it is possible to provide a retardation plate excellent in optical characteristics and heat resistance, exhibiting a uniform retardation, and free from optical axis fluctuation, and a method for producing the same.

Description

  The present invention relates to a cyclic olefin ring-opening copolymer that can be stretched at a relatively low temperature without causing problems such as cloudiness. The present invention also relates to a film, a sheet and a retardation plate containing such a cyclic olefin ring-opening copolymer, and a method for producing the retardation plate.

  The cyclic olefin ring-opening (co) polymer has a high glass transition temperature due to the rigidity of the main chain structure, and is amorphous and has a high light transmittance due to the presence of bulky groups in the main chain structure. In addition, it has features such as low birefringence due to its low refraction anisotropy, and has attracted attention as a transparent thermoplastic resin excellent in heat resistance, transparency and optical properties. Examples of the cyclic olefin-based ring-opening (co) polymer include those described in Patent Documents 1 to 6, for example.

  In recent years, using the above-mentioned features, for example, in the fields of optical materials such as optical disks, optical lenses, optical fibers, sealing materials such as optical semiconductor sealing, and the like, cyclic olefin ring-opening (co) polymers have been applied. Is being considered. In addition, attempts have been made to improve the problems of conventional optical films by applying to films or sheets (hereinafter referred to as films including sheets).

  In other words, films such as polycarbonate, polyester, and triacetyl acetate that have been used as optical films in the past have a large photoelastic coefficient. In order to solve these problems, films made of cyclic olefin-based ring-opening (co) polymers have been proposed as various optical films. For example, Patent Documents 7 to 10 describe a phase difference plate (an optical film having a function of imparting a phase difference to transmitted light, also referred to as a phase difference film) made of a cyclic olefin-based ring-opening (co) polymer film. Has been. Patent Documents 11 to 13 describe that a film of a cyclic olefin-based ring-opening (co) polymer is used as a protective film for a polarizing plate. Furthermore, Patent Document 14 describes a substrate for a liquid crystal display element comprising a film of a cyclic olefin-based ring-opening (co) polymer.

  By the way, in recent years, with the increase in size and functionality of liquid crystal display elements (LCDs), the required characteristics for retardation plates used in LCDs have become more sophisticated. Therefore, higher levels of uniformity and no optical axis blur are required, and control of the phase difference in the thickness direction is required to improve the viewing angle of LCDs. Therefore, in order to meet these requirements, ring-opening homopolymers (homopolymers) and ring-opening copolymers of various cyclic olefin monomers have been proposed as materials for retardation plates.

However, in the case of a homopolymer, the characteristics of the polymer obtained are uniquely determined by the characteristics of the cyclic olefin monomer used, and there is a limit to responding to all the various required characteristics.
On the other hand, in the case of a copolymer, stretching near the glass transition temperature (hereinafter also referred to as Tg) of the copolymer may cause the film after stretching to become cloudy or reduce the uniformity of retardation. Serious problems may occur. Of course, these problems can be avoided by increasing the film stretching temperature and stretching, but the stretching ratio for obtaining a desired retardation value decreases because the retardation develops when stretched at a high temperature. There is a problem in controlling the retardation value, such as increasing the thickness of the film or increasing the film thickness.

Therefore, it has excellent properties of cyclic olefin resins such as heat resistance and transparency, and also causes problems such as cloudiness even when film forming or film stretching is performed at a relatively low temperature such as near Tg. However, a resin suitable for applications such as a retardation plate has been strongly desired.
As a result of intensive studies in view of such circumstances, the present inventor has found that a cyclic olefin having a polar group and a hydrocarbon group, and a tricyclo [4.3.0.1 ^2,5 ] deca which may have a substituent. -3
A cyclic olefin-based ring-opening copolymer obtained from -ene and a cyclic olefin having no polar group such as bicyclo [2.2.1] hept-2-ene is stretched under a temperature condition near Tg. However, no problems such as white turbidity occurred, and the present invention was found to be suitable for use as a film or sheet and a retardation plate.
Japanese Patent Laid-Open No. 1-132625 JP-A-1-132626 JP 63-218726 A JP-A-2-133413 JP 61-120816 A Japanese Patent Laid-Open No. 61-115912 JP-A-4-245202 JP-A-4-36120 JP-A-5-2108 Japanese Patent Laid-Open No. 5-64865 Japanese Patent Laid-Open No. 5-212828 JP-A-6-511117 JP-A-7-77608 JP-A-5-61026

  The present invention is capable of meeting high-level characteristic requirements as a retardation plate, does not cause problems such as white turbidity even when stretched under a temperature condition near the glass transition temperature (Tg), and is suitable for film or sheet use. Another object of the present invention is to provide a cyclic olefin-based ring-opening copolymer that is suitable for sheet use, has a uniform desired retardation, and can easily obtain a retardation plate free from optical axis fluctuation. . It is another object of the present invention to provide a film or sheet containing the cyclic olefin-based ring-opening copolymer, a retardation plate comprising the film or sheet, and a method for producing the retardation plate.

  The cyclic olefin ring-opening copolymer of the present invention is a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), and a structural unit represented by the following formula (3). Characterized by having;

(In formula (1), m is 0, 1 or 2, X is independently a group represented by the formula: —CH═CH— or a group represented by the formula: —CH ₂ CH ₂ —, R ^{1 to} R ⁴ are each independently a hydrogen atom; a halogen atom; a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms which may have a linking group containing oxygen, nitrogen, sulfur or silicon; or Represents a polar group, provided that at least one of R ^{1 to} R ⁴ is a polar group and at least one of the other R ^{1 to} R ⁴ is a hydrocarbon group having 1 to 10 carbon atoms).

(In formula (2), X is independently a group represented by the formula: —CH═CH— or a group represented by the formula: —CH ₂ CH ₂ —, and R ^{5 to} R ¹⁰ are each independently hydrogen. An atom; a halogen atom; a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms which may have a linking group containing oxygen, nitrogen, sulfur or silicon; or a polar group.

(In the formula (3), n is 0, 1 or 2, X is independently a group represented by the formula: —CH═CH— or a group represented by the formula: —CH ₂ CH ₂ —, R ^{11 to} R ¹⁴ are each independently a hydrogen atom; a halogen atom; or a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms which may have a linking group containing oxygen, nitrogen, sulfur or silicon. Represents.)
The cyclic olefin ring-opening copolymer of the present invention preferably has a DSC differential differential scanning calorimetry curve having a single peak and a glass transition temperature (Tg) of 110 ° C. or higher.

The cyclic olefin-based ring-opening copolymer of the present invention preferably has no structural unit other than the structural units represented by the formulas (1) to (3).
In the cyclic olefin-based ring-opening copolymer of the present invention, the polar group in the structural unit represented by the formula (1) is preferably a group represented by the following formula (4);
− (CH ₂ ) _p COOR ′ (4)
(In Formula (4), p is 0 or an integer of 1 to 5, and R ′ is a hydrocarbon group having 1 to 15 carbon atoms).

The film or sheet of the present invention includes the cyclic olefin-based ring-opening copolymer of the present invention.
The retardation film of the present invention is characterized in that the film or sheet of the present invention is stretched and oriented.
In the method for producing a retardation plate of the present invention, the film or sheet of the present invention is stretched and oriented under a temperature condition of Tg to (Tg + 10) ° C. of the cyclic olefin copolymer contained in the film or sheet. It is characterized by.

  According to the present invention, it is excellent in heat resistance and optical properties, can suitably form a film or sheet, and can be stretched without causing problems such as cloudiness even at a relatively low temperature near Tg. A cyclic olefin copolymer can be provided. Moreover, according to this invention, the film or sheet | seat which is excellent in the optical characteristic and heat resistance containing such a cyclic olefin type copolymer, and is suitable also for extending | stretching at a comparatively low temperature can be provided. Furthermore, according to the present invention, it is possible to provide a retardation plate excellent in optical characteristics and heat resistance, exhibiting a uniform retardation, and free from optical axis fluctuation, and a method for producing the same.

These show the < ¹ > H-NMR measurement chart of copolymer (1 ') which is the copolymer before hydrogenation obtained in Example 1. FIG. These show the < ¹ > H-NMR measurement chart of the copolymer (1) which is the copolymer after hydrogenation obtained in Example 1. FIG.

Hereinafter, the present invention will be specifically described.
<Cyclic olefin copolymer>
The cyclic olefin ring-opening copolymer of the present invention is a structural unit represented by the above formula (1), a structural unit represented by the above formula (2), and a structural unit represented by the above formula (3). Have
The structural unit represented by the formula (1) is derived from a cyclic olefin monomer (1) represented by the following formula (1 ′) by ring-opening copolymerization.

(In the formula (1 ′), m and R ^{1 to} R ⁴ are the same as those in the formula (1), m is 0, 1 or 2, and R ^{1 to} R ⁴ are each independently a hydrogen atom; A halogen atom; a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms which may have a linking group containing oxygen, nitrogen, sulfur or silicon; or a polar group, provided that R ^{1 to} R ⁴ And at least one of the other R ^{1 to} R ⁴ is a hydrocarbon group having 1 to 10 carbon atoms.)
In the formula (1) or the formula (1 ′), examples of the polar group include a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, a carbonyloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, a cyano group, an amide group, Examples thereof include an imide group, a triorganosiloxy group, a triorganosilyl group, an amino group, an acyl group, an alkoxysilyl group, a sulfonyl group, and a carboxyl group. More specifically, examples of the alkoxy group include a methoxy group and an ethoxy group; examples of the carbonyloxy group include an alkylcarbonyloxy group such as an acetoxy group and a propionyloxy group, and an aryl such as a benzoyloxy group. Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group; examples of the aryloxycarbonyl group include a phenoxycarbonyl group, a naphthyloxycarbonyl group, a fluorenyloxycarbonyl group, Biphenylyloxycarbonyl group and the like; examples of the triorganosiloxy group include trimethylsiloxy group and triethylsiloxy group; examples of the triorganosilyl group include trimethylsilyl group, Such Riechirushiriru group and the like; examples of the amino group include primary amino group, the alkoxysilyl group, for example trimethoxysilyl groups, such as triethoxysilyl group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom.
Examples of the hydrocarbon group having 1 to 10 carbon atoms include alkyl groups such as methyl group, ethyl group, and propyl group; cycloalkyl groups such as cyclopentyl group and cyclohexyl group; alkenyl groups such as vinyl group, allyl group, and propenyl group. Groups and the like.
The substituted or unsubstituted hydrocarbon group may be directly bonded to the ring structure, or may be bonded via a linkage. Examples of the linking group include a divalent hydrocarbon group having 1 to 10 carbon atoms (for example, an alkylene group represented by — (CH ₂ ) _m — (wherein m is an integer of 1 to 10)); oxygen , A linking group containing nitrogen, sulfur or silicon (for example, a carbonyl group (—CO—), an oxycarbonyl group (—O (CO) —), a sulfone group (—SO ₂ —), an ether bond (—O—), Thioether bond (—S—), imino group (—NH—), amide bond (—NHCO—, —CONH—), siloxane bond (—OSi (R ₂ ) — (wherein R is an alkyl such as methyl or ethyl) Group)) and the like, and a linking group containing a plurality of these may be used.

Specifically, as the cyclic olefin monomer (1), for example,
5-methyl-5-methoxycarbonyl-bicyclo [2.2.1] hept-2-ene,
5-methyl-5-phenoxycarbonyl-bicyclo [2.2.1] hept-2-ene,
5-methyl-6-methoxycarbonyl-bicyclo [2.2.1] hept-2-ene,
5-methyl-6-phenoxycarbonyl-bicyclo [2.2.1] hept-2-ene,
8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-ethoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene,
8-methyl-8-n-propoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene,
8-methyl-8-isopropoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene,
8-methyl-8-n-butoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene,
8-methyl-8-phenoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene etc. can be mentioned, but it is not limited to these examples.

In the present invention, the polar group in the structural unit represented by the formula (1) is preferably a group represented by the following formula (4). That is, in the structural unit represented by the formula (1) or the cyclic olefin monomer (1) represented by the formula (1 ′), at least one of R ^{1 to} R ⁴ is represented by the following formula (4). It is preferable that it is group represented by these.
− (CH ₂ ) _p COOR ′ (4)
(In Formula (4), p is 0 or an integer of 1 to 5, and R ′ is a hydrocarbon group having 1 to 15 carbon atoms.)
In the above formula (4), the smaller the value of n and the smaller R ′ is, the higher the glass transition temperature of the copolymer obtained and the better the heat resistance. That is, n is usually 0 or an integer of 1 to 5, preferably 0 or 1, and R 'is usually a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 3 carbon atoms. It is desirable that it is an alkyl group.

Further, in the above formula (1), when an alkyl group is further bonded to the carbon atom to which the polar group represented by the above general formula (4) is bonded, the heat resistance and water absorption ( It is preferable in order to balance the wetness). The alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 2, and particularly preferably 1.
The structural unit represented by the formula (2) is derived from a cyclic olefin monomer (2) represented by the following formula (2 ′) by ring-opening copolymerization.

(In the formula (2 ′), R ^{5 to} R ¹⁰ are the same as in the formula (2), and each independently has a hydrogen atom; a halogen atom; a linking group containing oxygen, nitrogen, sulfur or silicon. A good substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms; or a polar group.)
In the formula (2) or (2 ′), the halogen atom, hydrocarbon group, and polar group are the same as those described for the formula (1) or (1 ′).

As such a cyclic olefin monomer (2), specifically, for example,
Tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-methyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
8-methyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-ethyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-isopropyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-cyclohexyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-phenyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7,7-dimethyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7,8-dimethyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-methyl-8-ethyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-methoxycarbonyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
8-methoxycarbonyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-phenoxycarbonyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-methyl-7-methoxycarbonyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
8-methyl-8-methoxycarbonyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-fluoro-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
8-fluoro-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-chloro-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
8-chloro-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7,7-difluoro-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7,8-difluoro-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7,8-Dichloro-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene and the like can be mentioned, but are not limited to these examples.

The structural unit represented by the formula (2) is a cyclic olefin monomer (2-2) represented by the following formula (where R ^{5 to} R ⁷ and R ⁹ are the same as in the formula (2)). ) Can be obtained by ring-opening copolymerization and then hydrogenating the five-membered ring.

As such a cyclic olefin monomer (2-2), specifically, for example,
Tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene (DCP),
7-methyl-tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene,
8-methyl-tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene,
9-methyl-tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene,
7,8-dimethyl-tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene,
7-ethyl-tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene,
7-cyclohexyl-tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene;
7-phenyl-tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene,
7- (4-biphenyl) -tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene 7-methoxycarbonyl-tricyclo [4.3.0.1 ^2,5 ] deca-3, 7-diene,
7-phenoxycarbonyl-tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene;
7-methyl-7-methoxycarbonyl-tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene;
7-fluoro-tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene,
7,8-difluoro-tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene,
Examples thereof include 7-chloro-tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene, but are not limited to these examples. Of these, tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene is particularly preferably used in the present invention.

  The structural unit represented by the formula (3) is derived from a cyclic olefin monomer (3) represented by the following formula (3 ′) by ring-opening copolymerization.

(In the formula (3 ′), n is 0, 1 or 2, and R ^{11 to} R ¹⁴ each independently have a hydrogen atom; a halogen atom; or a linking group containing oxygen, nitrogen, sulfur or silicon. Represents a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms.
As such a cyclic olefin monomer (3), specifically, for example,
Bicyclo [2.2.1] hept-2-ene,
Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene,
Hexacyclo [6.6.1.1 ^3,6 . 1 ^10,13 . 0 ^2,7 . 0 ^9,14 ] hept-4-ene 5-ethyl-bicyclo [2.2.1] hept-2-ene,
Examples include 5-methyl-bicyclo [2.2.1] hept-2-ene, but are not limited to these examples. Of these, bicyclo [2.2.1] hept-2-ene is particularly preferably used.

The cyclic olefin-based ring-opening copolymer of the present invention comprises one or more cyclic olefin-based monomers (1), cyclic olefin-based monomers (2) (or (2-2)), and cyclic olefin-based polymers, respectively. The monomer (3) can be produced by ring-opening copolymerization. The cyclic olefin-based ring-opening copolymer of the present invention contains 8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene, tricyclo [4.3.0.1 ^2,5 ] deca-3,7-diene and bicyclo [2.2.1] hept-2-ene. It is particularly preferred that there is.

  In the present invention, the copolymerization ratio of the cyclic olefin monomer (1), the cyclic olefin monomer (2) (or (2-2)) and the cyclic olefin monomer (3) is the sum of these. Is usually 50 to 90 parts by weight of the cyclic olefin monomer (1), and 10 to 40 parts by weight of the cyclic olefin monomer (2) (or (2-2)). The cyclic olefin monomer (3) is in the range of 0.5 to 20 parts by weight, preferably 50 to 80 parts by weight of the cyclic olefin monomer (1) and the cyclic olefin monomer (2 ) (Or (2-2)) is preferably in the range of 10 to 30 parts by weight and the cyclic olefin monomer (3) in the range of 1 to 10 parts by weight. When the amount of the cyclic olefin monomer (1) exceeds 90 parts by weight, the glass transition temperature of the resulting polymer may become too high, making extrusion molding difficult. The glass transition temperature can be adjusted by copolymerizing the cyclic olefin monomer (2) (or (2-2)), but when it exceeds 40 parts by weight, the resulting polymer in solution Filtration performance may deteriorate. Therefore, by using a small amount of the cyclic olefin monomer (3) as a copolymerization monomer together with the cyclic olefin monomer (2), the extrusion having the target glass transition temperature without lowering the filtration performance. A polymer excellent in moldability can be obtained.

  In the present invention, in addition to these cyclic olefin-based monomers (1), (2) (or (2-2)) and (3), other cyclic olefin-based ones are within the range not impairing the object of the present invention. A small amount of a monomer or other copolymerizable monomer can be used as a copolymerization raw material monomer, and the cyclic olefin-based ring-opening copolymer according to the present invention has the formulas (1), (2) and (3). Structural units other than the structural unit represented can be contained. Such structural units include, for example, cycloolefin monomers such as cyclobutene, cyclopentene, cycloheptene, cyclooctene and the like, and the cyclic olefin monomers (1), (2) (or (2-2)) and (3 ) And ring-opening copolymerization. In addition, in the presence of an unsaturated hydrocarbon polymer having an olefinically unsaturated bond in the main chain such as polybutadiene, polyisoprene, styrene-butadiene copolymer, ethylene-nonconjugated diene copolymer, polynorbornene, etc. It can also be formed by ring-opening copolymerization of the olefinic monomers (1), (2) (or (2-2)) and (3). The impact resistance of the copolymer of the present invention tends to be improved.

  However, in the present invention, it is preferable to carry out copolymerization using only the cyclic olefin monomers (1), (2) (or (2-2)) and (3). That is, the cyclic olefin-based ring-opening copolymer according to the present invention has other structures in addition to the structural units represented by the formulas (1), (2) and (3) as long as the object of the present invention is not impaired. Although it may have a unit, it is preferable not to have a structural unit other than the structural units represented by the formulas (1), (2) and (3).

  Copolymerization of each cyclic olefin monomer can be carried out by appropriately selecting the polymerization conditions in consideration of the reactivity of each monomer used. During copolymerization, it is preferable that the monomer composition ratio in the polymerization system does not change significantly between the initial and late stages of polymerization, and when the monomer concentration changes over time, the polymerization is stopped at an early stage. Alternatively, it is preferable to keep the monomer composition ratio constant by supplying the monomer having a reduced concentration into the polymerization system continuously or intermittently into the polymerization system. When copolymerization is performed while controlling the monomer composition ratio in this way, a copolymer capable of forming an optical film excellent in transparency can be obtained.

A ring-opening copolymer obtained by ring-opening copolymerization of each cyclic olefin-based monomer has an olefinic unsaturated bond in the molecule and has problems such as heat-resistant coloring. The olefinically unsaturated bond is preferably hydrogenated, but a known method can be applied to the hydrogenation reaction.
For example, the catalysts, solvents, temperature conditions, and the like described in JP-A-63-218726, JP-A-1-132626, JP-A-1-240517, JP-A-2-10221, and the like are applied. The ring-opening polymerization reaction and the hydrogenation reaction can be carried out.

  The hydrogenation rate of the olefinically unsaturated bond is usually 80 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more. In addition, as described above, the hydrogenation reaction in the present invention is for an olefinically unsaturated bond in the molecule, and when the cyclic olefin-based ring-opening copolymer of the present invention has an aromatic group, such aromatics The group does not necessarily need to be hydrogenated because it may have an advantageous effect on optical properties such as refractive index and heat resistance.

  As the molecular weight of the cyclic olefin-based ring-opening copolymer of the present invention, the number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC) is usually 8000 to 1,000,000, preferably The weight average molecular weight (Mw) in terms of polystyrene is usually 10,000 to 3,000,000, preferably 20,000, and is 10,000 to 500,000, more preferably 10,000 to 100,000. It is desirable to be in the range of ˜1,000,000, more preferably 30,000 to 500,000.

When the molecular weight is too small, the strength of the obtained film may be low. On the other hand, when the molecular weight is excessive, the solution viscosity becomes too high, and the productivity and processability of the copolymer of the present invention may deteriorate.
The molecular weight distribution (Mw / Mn) of the copolymer of the present invention is usually 1.5 to 10, preferably 2 to 8, and more preferably 2.2 to 5.

  The cyclic olefin ring-opening copolymer of the present invention has a saturated water absorption at 23 ° C. of usually 0.01 to 1% by weight, preferably 0.05 to 0.7% by weight, more preferably 0.1 to 0%. .5% by weight is desirable. If the saturated water absorption rate of the copolymer of the present invention is within the above range, various optical properties, transparency, retardation and retardation uniformity, or dimensional accuracy of the obtained film are high temperature and high humidity. It is stable even under conditions and has excellent adhesion and adhesion to other materials, so there is no peeling during use, and it is compatible with additives such as antioxidants. Since it is favorable, the freedom degree of selection of the kind and addition amount of an additive becomes large.

When this saturated water absorption is less than 0.01% by weight, the resulting film has low adhesion and adhesiveness to other materials, tends to cause peeling during use, and an antioxidant. The amount of additives such as these may be limited. On the other hand, when the saturated water absorption exceeds 1% by weight, the water absorption tends to cause changes in optical characteristics and dimensional changes.
Here, the saturated water absorption is a value obtained by immersing in water at 23 ° C. for 1 week and measuring an increased weight in accordance with ASTM D570.

  The glass transition temperature (Tg) of the cyclic olefin-based ring-opening copolymer of the present invention is usually 110 to 250 ° C, preferably 115 to 220 ° C, more preferably 120 to 200 ° C. A Tg of 110 ° C. or higher is preferable because of excellent heat resistance. When Tg is less than 110 ° C., the heat distortion temperature becomes low, which may cause a problem in heat resistance, and there may be a problem that a change in optical properties due to temperature in the obtained film becomes large. is there. On the other hand, when Tg exceeds 250 ° C., the processing temperature becomes too high during the drawing process, and the copolymer of the present invention may be thermally deteriorated.

Further, the cyclic olefin-based ring-opening copolymer of the present invention has a DSC differential differential scanning calorimetry curve showing a single peak, and a Tg distribution which is a rising temperature width of the peak is 40 ° C. or less, preferably 35 ° C. or less. It is preferable to have such a narrow distribution. The differential scanning calorimetric curve of DSC used in the present invention is obtained when measured in a nitrogen atmosphere at a heating rate of 20 ° C./min. The peak rising temperature width is the width between the inflection points where the peak rises from the baseline. Furthermore, the Tg of the cyclic olefin-based ring-opening copolymer is plotted on the differential scanning calorimetry curve with the maximum differential peak temperature (point A) of differential differential scanning calorific value and the temperature (point B) of −20 ° C. from the maximum peak temperature. , And the intersection of the tangent line on the baseline starting from point B and the tangent line starting from point A.
<Additives>
To the cyclic olefin-based ring-opening copolymer of the present invention, additives such as known antioxidants and ultraviolet absorbers are added for the purpose of improving heat deterioration resistance and light resistance within a range not impairing the effects of the present invention. can do. For example, at least one compound selected from the group consisting of the following phenol compounds, thiol compounds, sulfide compounds, disulfide compounds, and phosphorus compounds may be 0.01% with respect to 100 parts by weight of the copolymer of the present invention. By adding -10 parts by weight, the heat deterioration resistance can be improved.
-Phenol compounds As the phenol compounds, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) proonate], 1,6-hexanediol-bis [3- (3 , 5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -3,5 -Triazine, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylenebis [3- (3,5-di-t- Butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], N, N Hexamethylene bis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl -4-hydroxybenzyl) benzene, tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, 3,9-bis [2- [3- (3-t-butyl-4 -Hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane. Preferably, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,3,5-trimethyl-2,4,6-tris (3,5-di-t- Butyl-4-hydroxybenzyl) benzene, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], particularly preferably octadecyl-3- (3 5-di-t-butyl-4-hydroxyphenyl) propionate] and the like.
Thiol compounds As thiol compounds, alkyl mercaptans such as t-dodecyl mercaptan and hexyl mercaptan, 2-mercaptobenzimidazole, 2-mercapto-6-methylbenzimidazole, 1-methyl-2- (methylmercapto) benzimidazole 2-mercapto-1-methylbenzimidazole, 2-mercapto-4-methylbenzimidazole, 2-mercapto-5-methylbenzimidazole, 2-mercapto-5,6-dimethylbenzimidazole, 2- (methylmercapto) benz Examples include imidazole, 1-methyl-2- (methylmercapto) benzimidazole, 2-mercapto-1,3-dimethylbenzimidazole, mercaptoacetic acid, and the like.
-Sulfide compounds As the sulfide compounds, 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2-thiobis (4-methyl- 6-t-butylphenol), 2,4-bis (n-octylthiomethyl) -6-methylphenol, dilauryl 3,3′-thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl 3 , 3′-thiodipropionate, pentaerythrityltetrakis (3-laurylthiopropionate), ditridecyl 3,3′-thiodipropionate, and the like.
・ Disulfide compounds Disulfide compounds include bis (4-chlorophenyl) disulfide, bis (2-chlorophenyl) disulfide, bis (2,5-dichlorophenyl) disulfide, bis (2,4,6-trichlorophenyl) disulfide, bis (2-nitrophenyl) disulfide, ethyl 2,2′-dithiodibenzoate, bis (4-acetylphenyl) disulfide, bis (4-carbamoylphenyl) disulfide, 1,1′-dinaphthyl disulfide, 2,2′- Dinaphthyl disulfide, 1,2'-dinaphthyl disulfide, 2,2'-bis (1-chlorodinaphthyl) disulfide, 1,1'-bis (2-chloronaphthyl) disulfide, 2,2'-bis (1 -Cyanonaphthyl) disulfide, 2,2'-bis (1-acetyl) Fuchiru) disulfide, and the like dilauryl-3,3'-thiodipropionate.
Phosphorus compounds As phosphorus compounds, tris (4-methoxy-3,5-diphenyl) phosphite, tris (nonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, and the like.

  Further, benzophenone compounds such as 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone, benzotriazole compounds such as N- (benzyloxycarbonyloxy) benzotriazole, 2-ethyloxanilide, 2-ethyl By adding 0.01 to 3 parts by weight, preferably 0.05 to 2 parts by weight, based on 100 parts by weight of the copolymer of the present invention, an oxanilide-based compound such as -2'-ethoxyoxanilide, Light resistance can be improved.

  In addition, the cyclic olefin-based ring-opening copolymer according to the present invention, when formed into a film or the like by melt extrusion, in order to prevent the ring-opening copolymer from being thermally deteriorated due to the heat history at the time of melt extrusion. Selecting an antioxidant to be added is an important technical factor. That is, when a film obtained by melt extrusion is stretched, the glass transition of the cyclic olefin-based ring-opening copolymer to be melt-extruded in order to reduce the retardation or minimize the degree of decrease. It is preferable to use, as an antioxidant, a hindered phenol compound having a melting point in the temperature range of + 20 ° C. to Tg + 130 ° C., preferably Tg + 30 ° C. to Tg + 130 ° C., rather than the temperature (Tg).

  If the melting point is less than + 20 ° C. than the Tg of the cyclic olefin ring-opening copolymer to be melt-extruded, even if a hindered phenol-based compound is used, the increase in the amount of retardation greatly decreases. There are things to do. On the other hand, if the melting point exceeds + 130 ° C. than the Tg of the cyclic olefin ring-opening copolymer to be melt-extruded, the antioxidant may not be dissolved during processing, which may cause film defects such as fish eyes and foreign matters. . In addition, even when the melting point is Tg + 20 ° C. to Tg + 130 ° C. of the cyclic olefin-based ring-opening copolymer, when a compound other than the hindered phenol-based compound is used as an antioxidant, a reduction in retardation is observed. There is a case.

  Specific examples of the antioxidant preferably used when the cyclic olefin ring-opening copolymer of the present invention is formed by melt extrusion include, for example, 1,3,5-trimethyl-2,4,6-tris ( 3,5-di-t-butyl-4-hydroxybenzyl) benzene, N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamide), tris- (3,5- Di-t-butyl-4-hydroxybenzyl) -isocyanate, tris (2,4-di-t-butylphenyl) phosphite, and the like, but the present invention is not limited to these, and these In some cases, the Tg of the cyclic olefin ring-opening copolymer to be melt-extruded may be unsuitable. In addition, as long as the effect of this invention is not impaired, these may be used in combination and may be used independently.

  The addition amount of these antioxidants is usually 0.01 to 5 parts by weight, preferably 0.05 to 4 parts by weight, and more preferably 0 to 100 parts by weight of the cyclic olefin ring-opening copolymer. 0.1 to 1.5 parts by weight. When the addition amount of the antioxidant is less than 0.01 parts by weight, a gel is likely to be generated in the resin during the extrusion process, and as a result, it may be recognized as a defect on the obtained film. There is not preferable. On the other hand, if the amount of the additive exceeds 5 parts by weight, it may cause the formation of eyes and the like during processing, and this eye and eyes may cause die lines, fish eyes on the film, and burns, which is not preferable.

Such an antioxidant may be added when the cyclic olefin ring-opening copolymer is produced, or may be blended together with the pellets of the cyclic olefin ring-opening copolymer when melt-extruding.
Further, in the case of molding the cyclic olefin-based ring-opening copolymer of the present invention by melt extrusion, as long as the effects of the present invention are not impaired, lubricants, ultraviolet absorbers, dyes or pigments other than the above antioxidants Additives can be used. Of course, even in this case, in the case of an additive having a melting point, the melting point is preferably in the range of the melting point of the essential antioxidant of the present invention.

  When the cyclic olefin-based ring-opening copolymer according to the present invention is used for production of a film or sheet, a retardation plate, etc., the amount of foreign matter / gel contained in the copolymer is as small as possible. Is preferred. When there are a lot of foreign objects and gels, fish-eye defects and die lines occur in the extruded film obtained by melt molding, resulting in a film with insufficient surface accuracy, especially for use in optical applications. Sometimes.

In the present invention, in order to obtain a film having good surface properties, the gel content contained in 1 g of the copolymer to be used is preferably 30 or less, more preferably 20 or less, particularly 10 The following is preferable.
Here, the gel content contained in 1 g of the copolymer can be measured, for example, as follows. Ie;
The precisely weighed copolymer is filtered through a 0.1 μm membrane filter and dissolved in tetrahydrofuran (THF) from which foreign matters have been completely removed, and this resin solution is subjected to suction filtration using a 0.5 μm membrane filter.

The membrane filter after filtration is heated in a muffle furnace at 260 ° C. for about 30 minutes.
The gel on the membrane filter (observed as “buzz” discolored to brown or the like) is observed with a 20 × stereo microscope, and the number is counted.
Further, in the present invention, in order to obtain a film having a good surface property, it is preferable that there is no foreign matter of 50 μm or more contained in the cyclic olefin-based ring-opening copolymer to be used, and there is no foreign matter of 20 μm or more. In particular, it is preferable that there is no foreign matter of 10 μm or more. In addition, the foreign material in a copolymer can be measured as follows, for example. That is, 10 g of copolymer is filtered through a 0.1 μm membrane filter and dissolved in tetrahydrofuran (THF) from which foreign matters are completely removed, and the number of foreign matters of 10 μm, 20 μm, and 50 μm is counted by a particle counter (light scattering method). To do. Unless observed by this method, it is defined that the corresponding size of foreign matter is not present in the copolymer.
<Film or sheet>
The cyclic olefin-based ring-opening copolymer of the present invention can be formed into a film by a known solution casting method (solvent casting method, melt molding method, etc.), and thus the film or sheet according to the present invention ( Hereinafter, a film including a sheet can be obtained.
-Solvent Cast Method As the solvent cast method, for example, a film-forming solution containing the copolymer of the present invention at an appropriate concentration is prepared by dissolving or dispersing the copolymer resin of the present invention in a solvent. The film forming solution is cast by pouring or coating on a suitable carrier, thereby forming a liquid phase of the film forming solution on the carrier, and then removing the solvent by drying or the like on the liquid layer. A preferred method is to perform the treatment and peel the resulting film from the carrier.

  In the preparation of the film forming solution by the solvent casting method, the concentration of the copolymer of the present invention is usually 0.1 to 70% by weight, preferably 1 to 50% by weight, more preferably 10 to 35% by weight. is there. When this concentration is too small, it becomes difficult to obtain a film having a required thickness, and when the solvent is removed by drying, foaming or the like is likely to occur with evaporation of the solvent, and surface smoothness is obtained. It may be difficult to obtain a good film. On the other hand, if this concentration is excessive, the viscosity of the film-forming solution becomes too high, and it may be difficult to obtain a film having a uniform thickness and surface condition.

The viscosity of the film-forming solution is usually 1 to 1,000,000 (mPa · s), preferably 10 to 100,000 (mPa · s), more preferably 100 to 80,000 (mPa · s) at room temperature. s), particularly preferably 1000 to 60,000 (mPa · s).
Solvents used for the preparation of the film forming liquid include aromatic solvents such as benzene, toluene and xylene, cellosolve solvents such as methyl cellosolve, ethyl cellosolve and 1-methoxy-2-propanol, diacetone alcohol, acetone and cyclohexanone. Ketone solvents such as methyl ethyl ketone, 4-methyl-2-pentanone, cyclohexanone, ethyl cyclohexanone and 1,2-dimethylcyclohexane, ester solvents such as methyl lactate and ethyl lactate, 2,2,3,3-tetrafluoro- Examples thereof include halogen-containing solvents such as 1-propanol, methylene chloride and chloroform, ether solvents such as tetrahydrofuran and dioxane, and alcohol solvents such as 1-pentanol and 1-butanol.

Also in addition to the above solvent, SP value (solubility parameter) of usually 10 to 30 (MPa ^1/2), preferably 10 to 25 (MPa ^1/2), more preferably 15-25 (MPa ^1/2 ), And particularly preferably, by using a solvent in the range of 15 to 20 (MPa ^1/2 ), a film having good surface state uniformity and optical properties can be obtained.
Said solvent can be used individually or in combination of 2 or more types. When two or more solvents are used in combination, the SP value of the obtained mixed solvent is preferably within the above range. Here, the SP value of the mixed solvent can be determined from the SP value of each solvent and the weight ratio thereof. For example, in a mixed solvent obtained from two kinds of solvents, the weight fraction of each solvent is set to W1 and When W2 is set and SP values are SP1 and SP2, the SP value of the mixed solvent can be calculated by the formula: SP value = W1 · SP1 + W2 · SP2.

The temperature at which the copolymer of the present invention is dissolved or dispersed in the solvent may be room temperature or high, and by sufficiently stirring, a film-forming solution in which the copolymer of the present invention is uniformly dissolved or dispersed can be obtained. .
Moreover, coloring agents, such as dye and a pigment, can be suitably added to a film formation liquid as needed, and thereby a colored film can be obtained.

Moreover, you may add a leveling agent to a film formation liquid for the purpose of improving the surface smoothness of the film obtained. As such leveling agents, various ones can be used as long as they are general, and specific examples thereof include fluorine-based nonionic surfactants, special acrylic resin-based leveling agents, silicone-based leveling agents, and the like. .
As a carrier for forming the liquid layer of the film forming liquid, a metal drum, a steel belt, a polyester film made of polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), a polytetrafluoroethylene belt, or the like may be used. it can.

As a method for applying the film forming liquid, a method using a die or a coater, a spray method, a brush coating method, a roll coating method, a spin coating method, a dipping method, or the like can be used.
Moreover, the thickness and surface smoothness of the film obtained can also be controlled by repeatedly applying the film forming liquid.

  When a polyester film is used as the carrier, a surface-treated film may be used. Here, as a surface treatment method, a commonly-used hydrophilic treatment method, for example, a method of forming a layer made of these resins by coating or laminating an acrylic resin or a sulfonate group-containing resin. Or the method etc. which improve the hydrophilic property of the film surface by corona discharge treatment etc. are mentioned.

  In addition, as a carrier, for example, a metal drum, a steel belt, a polyester film, or the like that has been subjected to sand mat treatment or emboss treatment to form irregularities, the surface of the resulting film has irregularities on the surface of the carrier. Is transferred, whereby a film having a light diffusion function can be produced. Of course, it is also possible to impart a light diffusion function to the film by subjecting the film to a sand mat treatment.

  In the solvent casting method, a specific method for removing the solvent in the liquid layer is not particularly limited, and a commonly used drying treatment method, for example, a method of passing through a drying furnace with a large number of rollers is used. However, if bubbles are generated as the solvent evaporates in the drying step, the properties of the resulting film are significantly reduced. To avoid this, the drying step is divided into a plurality of steps of two or more steps. It is preferable to control the temperature or the air volume at.

  The amount of residual solvent in the film thus obtained is usually 10% by weight or less, preferably 5% by weight or less, more preferably 1% by weight or less, and particularly preferably 0.5% by weight or less. Here, when the residual solvent amount in the film exceeds 10% by weight, the dimensional change with time becomes large when the film is actually used, which is not preferable. Further, the residual solvent lowers the glass transition temperature and lowers the heat resistance, which is not preferable.

  In addition, in order to perform the extending | stretching process mentioned later suitably, it may be necessary to adjust the amount of residual solvents in a film suitably within the said range. Specifically, the amount of residual solvent in the film is usually 10 to 0.1% by weight, preferably 5 to 0.1% by weight, in order to stably and uniformly express the phase difference in the film by the stretching and orientation treatment. More preferably, it may be 1 to 0.1% by weight. By leaving a trace amount of solvent in the film, the stretching and orientation treatment may be facilitated or the retardation may be easily controlled.

  The thickness of the film of the present invention obtained by the solvent casting method is usually 0.1 to 3,000 μm, preferably 0.1 to 1,000 μm, more preferably 1 to 500 μm, and most preferably 5 to 300 μm. When this thickness is too small, it becomes difficult to actually handle the film. On the other hand, when this thickness is excessive, it becomes difficult to wind in a roll shape.

The thickness distribution of the film of the present invention obtained by the solvent casting method is usually within ± 20%, preferably within ± 10%, more preferably within ± 5%, particularly preferably within ± 3% relative to the average value. It is. Further, the variation rate of the thickness per 1 cm is usually 10% or less, preferably 5% or less, more preferably 1% or less, and particularly preferably 0.5% or less. By controlling the thickness distribution of the film within the above range, it is possible to prevent occurrence of retardation unevenness when the film is stretched and oriented.
・ Extrusion molding method (melt extrusion method)
The film of the present invention can also be obtained by melt extrusion molding the cyclic olefin-based ring-opening copolymer according to the present invention.

Hereinafter, although an example is given and demonstrated about facilities, such as an extruder used by this invention, this invention is not limited to these examples.
In the melt extrusion method of the present invention, usually, before the cyclic olefin ring-opening copolymer is charged into the extruder, moisture, gas (such as oxygen) contained in the cyclic olefin ring-opening copolymer, The resin is dried at an appropriate temperature not higher than Tg for the purpose of removing residual solvent and the like in advance.

  The dryer used for drying is not particularly limited. Usually, a hot air circulating dryer, a dehumidifying dryer, a vacuum dryer, an inert gas circulating dryer such as nitrogen is used, and a thermoplastic norbornene resin. It is particularly preferable to use an inert gas circulation drier or a vacuum drier from the viewpoint of efficiently removing volatile components or dissolved oxygen. In order to suppress moisture absorption and oxygen absorption in the hopper, it is also preferable to seal the hopper with an inert gas such as nitrogen or argon, or to use a vacuum hopper that can be kept under reduced pressure. Furthermore, the extruder cylinder may be provided with a vent function to remove volatile components generated during melt extrusion and a function to seal with an inert gas such as nitrogen or argon in order to push the deterioration of the polymer due to oxygen contamination. preferable.

As an extrusion molding method, the resin is melted by an extruder, and a fixed amount is supplied by a gear pump, impurities are removed by filtration with a metal filter, the film is shaped by a die, and the film is drawn by using a take-up machine. A method is generally used in which the is cooled and wound using a winder.
As an extruder used for extrusion molding, any of a single screw, a twin screw, a planetary type, a kneader, a Banbury mixer type and the like may be used, but a single screw extruder is preferably used. In addition, there are vent type, tip dull mage type, double flight type, full flight type, etc. as extruder screw shape, and compression type includes slow compression type, quick compression type, etc., but full flight type slow compression. Type is preferred.

  For gear pumps used for metering, there is an internal lubrication system in which the resin returned from the downstream side between gears enters the system and an external lubrication system that is discharged to the outside, but thermoplastic norbornene with poor thermal stability In the case of a resin, an external lubrication method is preferable. As for the gear teeth of the gear pump, the helical type is more preferable than the direction parallel to the shaft from the viewpoint of stabilization of measurement.

  Regarding the filter used for filtering foreign matter, there are leaf disc type, candle filter type, leaf type, screen mesh, etc., but leaf disc type with relatively small residence time distribution and large filtration area. Are preferred. Examples of the filter element include a metal fiber sintered type, a metal powder sintered type, and a metal fiber / powder laminated type.

The shape of the center pole of the filter includes external flow type, hexagonal column internal flow type, cylindrical internal flow type, etc., but any shape can be selected as long as the retention part is small, The external flow type is preferable.
The melted cyclic olefin-based ring-opening copolymer is discharged from a die, and is solidified in close contact with a cooling drum to be formed into a target film. Regarding the die shape, it is essential to make the resin flow inside the die uniform, and in order to maintain the uniformity of the film thickness, the pressure distribution inside the die near the die outlet must be constant in the width direction. Is essential. In addition, the flow rate of the resin in the width direction is almost constant, and the fine adjustment of the flow rate at the die outlet is constant within a range that can be adjusted by the lip opening. It is. In order to satisfy the above conditions, the coat hanger type is preferable for the manifold shape, and the straight manifold, fishtail type and the like are not preferable because the flow rate distribution in the width direction is likely to occur.

  Further, in order to make the thickness distribution of the film uniform, it is important to make the temperature distribution at the die exit constant in the width direction, and the temperature distribution is preferably ± 1 ° C. or less, more preferably ± 0.5 ° C. or less. If temperature unevenness exceeds ± 1 ° C in the width direction, a difference in melt viscosity of the resin occurs, resulting in uneven thickness, uneven stress distribution, etc., and therefore uneven retardation occurs during the stretching operation. It becomes easy and it is not preferable.

  Further, the lip opening amount of the die outlet (hereinafter referred to as “lip gap”) is usually 0.05 to 1 mm, preferably 0.3 to 0.8 mm, more preferably 0.35 to 0. 0.7 mm. If the lip gap is less than 0.05 mm, the resin pressure inside the die becomes too high, and the resin tends to leak from a place other than the lip of the die, which is not preferable. On the other hand, when the lip gap exceeds 1 mm, it is difficult to increase the resin pressure of the die, which is not preferable because the uniformity of the thickness in the width direction of the film is deteriorated.

Examples of methods for tightly solidifying the film extruded from the die include a nip roll method, an electrostatic application method, an air knife method, a vacuum chamber method, a calendar method, and the like, and an appropriate method is selected according to the film thickness and application. Is done.
Various surface treatments are preferably performed on the surface of the cooling roll for solidifying the film extruded from the die as well as the extruder cylinder and the inner surface of the die. These surface treatments prevent the adhesion of the extruded film to the roll surface and prevent the occurrence of uneven thickness of the film. Also, the surface accuracy of the cooling roll is increased, and the surface hardness is high, so that the film is not easily damaged. Even if it manufactures, it is preferable at the point which can maintain the film surface precision stably and can manufacture a film without a thickness spot.

Examples of the material of the extruder (cylinder, screw, etc.) and the die include, but are not limited to, SCM steel and stainless steel such as SUS. In addition, the inner surface of the extruder cylinder, the die and the screw surface of the extruder are plated with chromium, nickel, titanium, etc., PVD (Physical Vapor Deposition) method, etc., TiN, TiAlN, TiCN, CrN, DLC It is preferable to use a material in which a film such as (diamond-like carbon) is formed, a tungsten-based material such as WC, a material sprayed with a ceramic such as cermet, or a material whose surface is nitrided. Such a surface treatment is preferable in that a uniform molten state of the resin can be obtained because the coefficient of friction with the resin is small.

  In this invention, as resin temperature (extruder cylinder temperature) at the time of manufacturing a melt-extrusion film, it is 200-350 degreeC normally, Preferably it is 220-320 degreeC. If the resin temperature is less than 200 ° C., the resin cannot be melted uniformly. On the other hand, if the resin temperature exceeds 350 ° C., the resin is thermally deteriorated during melting, making it difficult to produce a high-quality film with excellent surface properties. . Furthermore, it is particularly preferable that the temperature is within the above-mentioned temperature range and within the range of Tg + 120 ° C. to Tg + 160 ° C. with respect to the glass transition temperature (Tg) of the resin. For example, if the Tg of the resin is 130 ° C., a particularly preferable temperature range for film production is 250 ° C. to 290 ° C.

  The shear rate during melt extrusion is usually 1 to 500 (1 / sec), preferably 2 to 350 (1 / sec), more preferably 5 to 200 (1 / sec). If the shear rate at the time of extrusion is less than 1 (1 / sec), the resin cannot be uniformly melted, and thus an extruded film with small thickness unevenness cannot be obtained, while if it exceeds 500 (1 / sec), In some cases, the shear force is too great, and the resin and additives are decomposed and deteriorated, and defects such as foaming, die lines, and deposits may occur on the surface of the extruded film.

  In the present invention, the thickness of the melt-extruded film is usually 10 to 800 μm, preferably 20 to 500 μm, more preferably 40 to 500 μm. When the thickness is less than 10 μm, it may be difficult to perform post-processing such as stretching due to insufficient mechanical strength. On the other hand, when the thickness exceeds 800 μm, a film having uniform thickness and surface properties is produced. In addition to being difficult, it may be difficult to wind up the resulting film.

The thickness distribution of the raw film of the present invention obtained by the melt extrusion method is usually within ± 5%, preferably within ± 3%, more preferably within ± 1% of the average value. If the thickness distribution exceeds ± 5%, retardation unevenness may easily occur when a retardation film is obtained by performing a stretching treatment.
<Phase difference plate and manufacturing method thereof>
The film of the present invention has a function of regularly aligning the molecular chains of the copolymer of the present invention forming the film in a certain direction and giving a phase difference to transmitted light by performing a stretching process (stretch orientation process). Thus, the retardation film according to the present invention can be obtained.

  Here, “regularly oriented” means that when a normal polymer compound (polymer) is formed into a film by a melt extrusion method or a casting method, the distortion of the film generated in the process is also small. However, while the molecular chain of the polymer compound is in a random state without facing a specific direction, the molecular chain of the polymer compound is regular in the uniaxial direction, biaxial direction, or thickness direction of the plane of the film. It means that it is oriented. The degree of regularity of the orientation of the polymer compound varies and can be controlled by the stretching conditions.

Specific examples of the stretching method include known uniaxial stretching methods and biaxial stretching methods. That is, by the horizontal uniaxial stretching method by the tenter method, the compression stretching method between rolls, the longitudinal uniaxial stretching method using two sets of rolls with different circumferences, or the biaxial stretching method combining the horizontal uniaxial and the longitudinal uniaxial, the inflation method A stretching method or the like can be used.
When the uniaxial stretching method is used, the stretching speed is usually 1 to 5,000% / min, preferably 50 to 1,000% / min, and more preferably 100 to 1,000% / min. Yes, particularly preferably 100 to 500% / min.

  As the biaxial stretching method, a method of stretching in two directions intersecting each other at the same time or a method of stretching in a direction different from the first stretching direction after uniaxial stretching can be used. In these methods, the intersecting angle between the two stretching axes is not particularly limited because it is determined according to the desired characteristics, but is usually in the range of 120 to 60 degrees. The stretching speed may be the same or different in each stretching direction, and is usually 1 to 5,000% / min, preferably 50 to 1,000% / min, and more preferably 100 -1,000% / min, particularly preferably 100-500% / min.

  The processing temperature in the stretching process is not particularly limited, but is usually in the range of Tg-5 ° C to Tg + 20 ° C, preferably Tg to Tg + 10 ° C, where Tg is the glass transition temperature of the copolymer used. Is desirable. By setting the treatment temperature within the above range, it is possible to suppress the occurrence of high phase difference and phase difference unevenness, and it is preferable because the control of the refractive index ellipsoid becomes easy.

  In addition, even if it draw-processes in the temperature range which concerns, as long as the cyclic olefin type ring-opening copolymer of this invention is used, problems, such as cloudiness, will not arise in the phase difference plate obtained. This is presumably because the copolymer of the present invention has a relatively small Tg distribution and is plasticized substantially uniformly by heating in the vicinity of Tg. Conversely, in the case of a cyclic olefin-based ring-opening copolymer having a large Tg distribution, it is not uniformly plasticized only by heating in the vicinity of Tg, and there is a partially unplasticized part. It is thought to cause white turbidity.

The draw ratio is not particularly limited because it is determined according to the desired properties such as retardation, but is usually 1.01 to 10 times, preferably 1.03 to 5 times, more preferably 1.03 to 3 times. It is.
In the case of the cyclic olefin ring-opening copolymer of the present invention, since it can be stretched in the vicinity of Tg, it is possible to apply a high stress to the film even at a low magnification, and thus a high retardation can be obtained. In addition, when the draw ratio is relatively low as described above, it is possible to easily produce a retardation plate without transparency and optical axis deviation. When the stretch ratio is excessive, it may be difficult to control the phase difference and the optical axis.

  Although the stretched film may be cooled as it is at room temperature, it is kept in a temperature atmosphere of about Tg-100 ° C. to Tg for at least 10 seconds, preferably 30 seconds to 60 minutes, more preferably 1 minute to 60 minutes. It is also preferable to heat-set and then cool to room temperature, whereby a retardation plate having stable retardation characteristics with little change over time in the retardation of transmitted light is obtained.

  The retardation plate obtained as described above gives a retardation to transmitted light due to the orientation of molecules by stretching. This retardation is determined by the stretching ratio or the thickness of the film before stretching. It is possible to control by adjusting. For example, as for the draw ratio, even if the film has the same thickness before drawing, the absolute value of the retardation of transmitted light tends to increase as the draw ratio increases. A film that imparts a retardation to transmitted light can be obtained. As for the thickness of the film before stretching, even if the stretching ratio is the same, the larger the thickness of the film before stretching, the greater the absolute value of the phase difference given to transmitted light. By changing the thickness of the retardation plate, it is possible to obtain a retardation plate that imparts a desired retardation to transmitted light.

  In the retardation plate obtained as described above, the value of the phase difference given to the transmitted light is determined depending on the use and is not uniquely determined. However, the liquid crystal display element or the electroluminescence display element is used. Or when using for the wavelength plate of a laser optical system, it is desirable that it is 1-10,000 nm normally, Preferably it is 10-2,000 nm, More preferably, it is 15-1,000 nm.

  Further, the phase difference of light transmitted through the film is preferably highly uniform. Specifically, the variation at a light wavelength of 550 nm is usually ± 20% or less, preferably ± 10% or less, more preferably. It is desirable that it be ± 5% or less. When the variation in the phase difference exceeds the range of ± 20%, when used in a liquid crystal display element or the like, color unevenness or the like may occur, resulting in a problem that the performance of the display body deteriorates. Similarly, the variation of the optical axis is usually ± 2.0 degrees or less, preferably ± 1.0 degrees or less, more preferably ± 0.5 degrees or less.

The retardation plate of the present invention can be used alone or in a laminate of two or more or bonded to a transparent substrate or the like. Moreover, it can also be laminated | stacked and used for another film, a sheet | seat, and a board | substrate.
When laminating a film or the like, a pressure-sensitive adhesive or an adhesive can be used. As the pressure-sensitive adhesive and adhesive, those having excellent transparency are preferably used. Specific examples thereof include natural rubber, synthetic rubber, vinyl acetate / vinyl chloride copolymer, polyvinyl ether, acrylic resin, and modified polyolefin. Adhesives such as resins, curable adhesives in which curing agents such as isocyanato group-containing compounds are added to the resins having functional groups such as hydroxyl groups and amino groups, polyurethane-based dry laminate adhesives, and synthetic rubber adhesives Agents, epoxy adhesives and the like.

In addition, a pressure-sensitive adhesive layer or an adhesive layer can be laminated in advance on the retardation plate in order to improve the workability of lamination with other films, sheets, substrates, and the like. In the case where the pressure-sensitive adhesive layer or the adhesive layer is laminated, the pressure-sensitive adhesive or the adhesive as described above can be used as the pressure-sensitive adhesive or the adhesive.
EXAMPLES Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples. In the following, parts or% are based on weight unless otherwise specified.

Various physical properties were measured or evaluated as follows.
Glass transition temperature (Tg )
Using a DSC6200 manufactured by Seiko Instruments Inc., the temperature increase rate was measured at 20 ° C. per minute under a nitrogen stream. Tg is the tangent on the baseline starting from point B, with the differential peak scanning calorie maximum peak temperature (point A) and the temperature at −20 ° C. from the maximum peak temperature (point B) plotted on the differential scanning calorimetry curve. And the intersection of the tangent starting from point A.
The hydrogenation rate nuclear magnetic resonance spectrometer (NMR) used was AVANCE 500 manufactured by Bruker, and ¹ H-NMR was measured using d-chloroform as the measurement solvent. The hydrogenation rate was calculated after calculating the monomer composition from the integral value of 5.1 to 5.8 ppm of vinylene group, 3.7 ppm of methoxy group, and 0.6 to 2.8 ppm of aliphatic proton.
Weight average molecular weight Using HLC-8020 gel permeation chromatography (GPC) manufactured by Tosoh Corporation, polystyrene-converted weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) were measured with tetrahydrofuran (THF) solvent. Mn represents a number average molecular weight.
The residual solvent amount sample was dissolved in toluene and measured using GC-14B gas chromatography manufactured by Shimadzu Corporation.
Filtration rate measurement Compact cartridge filter manufactured by ADVANTEC: MCP-HX-E10S (average pore diameter 2.0 μm, filtration area 2000 cm ² ), MCP-JX-E10S (average pore diameter 1.0 μm, filtration area 2000 cm ² ), MCS-020- E10SR (average pore size 0.2 μm, filtration area 1800 cm ² ) each one was connected in series in this order, and the polymer solution after hydrogenation was continuously filtered at room temperature with nitrogen pressure of 3.0 kgf / cm ² and filtered. The change in speed over time was measured. In addition, these filters were used using the housing for compact cartridges: MTA-2000T.
Film with phase difference unevenness, optical axis unevenness 20 cm long, 20 cm wide and 130 μm thick, stretching temperature: copolymer Tg + 5 ° C., 1.5 times under the condition of 300% / min in the longitudinal direction by free end uniaxial stretching method Drawing was performed. The film was cut into 312 cm ² with a length of 26 cm and a width of 12 cm from the center of the stretched film, and the phase difference was measured at intervals of 2 cm and 2 cm, and the optical axis was measured using an optical birefringence analyzer KOBRA-21ADH.

[Example 1]
8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene (DNM) 71 parts, dicyclopentadiene (DCP) 15 parts, and bicyclo [2.2.1] hept-2-ene (NB) 1 part are used as monomers. Together with 18 parts of molecular weight regulator 1-hexene and 200 parts of toluene were charged into a nitrogen-substituted reaction vessel and heated to 100 ° C.

To this, 0.005 part of triethylaluminum and 0.005 part of methanol-modified WCl ₆ (anhydrous methanol: PhPOCl ₂ : WCl ₆ = 103: 630: 427 weight ratio) were added and reacted for 1 minute, and then 10 parts of DCP and NB3 A copolymer (1 ') was obtained by adding another part in 5 minutes and making it react for another 45 minutes.
FIG. 1 shows a ¹ H-NMR measurement chart of the obtained copolymer (1 ′). A double bond of the main chain of the copolymer was observed at 5.2 to 5.6 ppm at 5.8 ppm in DCP-derived vinylene proton (Hc), 3.65 ppm at DNM-derived methoxy proton (He). The NB content in the copolymer is determined by subtracting the DCP structural unit (protons 3 times that of Hb) and the DNM structural unit (protons that are 2/3 times that of He), so that the monomer structural units in the copolymer are subtracted. As a result of the calculation, it was DNM / DCP / NB = 69.77 / 26.01 / 4.23 (wt%).

Subsequently, the solution of the obtained copolymer (1 ') was put into the autoclave, and 200 parts of toluene was further added. Next, 1 part of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate as a reaction modifier and RuHCl (CO) [P (C ₆ H ₅ )] as a hydrogenation catalyst After 0.06 part of ₃ was added and heated to 155 ° C., hydrogen gas was charged into the reactor, and the pressure was adjusted to 10 MPa. Thereafter, the reaction was carried out at 165 ° C. for 3 hours while maintaining the pressure at 10 MPa. After completion of the reaction, 100 parts by weight of toluene, 3 parts by weight of distilled water, 0.72 parts by weight of lactic acid and 0.00214 parts by weight of hydrogen peroxide were added and heated at 60 ° C. for 30 minutes. Thereafter, 200 parts by weight of methanol was added and heated at 60 ° C. for 30 minutes. When this was cooled to 25 ° C., it was separated into two layers. Remove 500 parts by weight of the supernatant, add 350 parts by weight of toluene and 3 parts by weight of water again, heat at 60 ° C. for 30 minutes, then add 240 parts by weight of methanol, heat at 60 ° C. for 30 minutes, and cool to 25 ° C. Separated into two layers. Remove 500 parts by weight of the supernatant, add 350 parts by weight of toluene and 3 parts by weight of water, heat at 60 ° C. for 30 minutes, then add 240 parts by weight of methanol, heat at 60 ° C. for 30 minutes, and cool to 25 ° C. Separated into two layers. Finally, after removing 500 parts by weight of the supernatant, the remaining polymer solution was filtered at a temperature of 50 ° C. with 2.0 μm, 1.0 μm and 0.2 μm filters connected in series. Thereafter, the polymer solution was concentrated to a solid content concentration of 55%, subjected to solvent removal treatment at 250 ° C., 4 torr and a residence time of 1 hour, and passed through a 10 μm polymer filter to obtain a copolymer (1). When the polymer solution before the solvent removal treatment was continuously filtered and the change in filtration rate with time was followed, the filter was not clogged after 1000 hours and the filtration rate did not decrease.

The obtained copolymer (1) has a weight average molecular weight (Mw) = 6.10 × 10 ⁴ , a molecular weight distribution (Mw / Mn) = 3.8, an intrinsic viscosity (η _inh ) = 0.52, and a glass transition. The temperature (Tg) was 131 ° C. Moreover, Tg distribution was 25 degreeC. A ¹ H-NMR chart of copolymer (1), which is a hydrogenated copolymer, is shown in FIG. From this, the hydrogenation rate of the copolymer (1) was determined, and the olefinically unsaturated bond was hydrogenated by 99.9% or more.

The copolymer (1) was formed into a film by melt extrusion to obtain a cast film (1) having a thickness of 130 μm. Thereafter, the stretched film (1) was obtained by stretching the copolymer (1) by Tx + 5 ° C., which is 136 ° C., and a free end uniaxial stretching method, stretching speed = 300% / min, 1.5 times.
The stretched film (1) had a thickness of 85 μm, a retardation of 343 nm, a birefringence of 0.00404, and a haze value of 0.1, and was confirmed to be a transparent film having no appearance defect. Moreover, the area which satisfy | fills the phase difference +/- 3nm and optical axis +/- 0.5 degrees or less after extending | stretching was 64 cm < ² >.

[Comparative Example 1]
In Example 1, a copolymer (2) was obtained in the same manner as in Example 1 except that 50 parts of DCP and 50 parts of DNM were used as monomers.
The copolymer (2) has a weight average molecular weight (Mw) = 13.3 × 10 ⁴ , a molecular weight distribution (Mw / Mn) = 4.0, an intrinsic viscosity (η _inh ) = 0.74, a glass transition temperature (Tg). ) = 130 ° C. Moreover, Tg distribution was 42 degreeC. In addition, when the hydrogenation rate of the copolymer (2) was calculated | required by < ¹ > H-NMR measurement, the olefinic unsaturated bond was hydrogenated 99.9% or more. Further, when the polymer solution before the solvent removal treatment was continuously filtered in the same manner as in Example 1 and the change in the filtration rate with time was followed, a decrease in the filtration rate was observed after 300 hours, and after 500 hours. Found that the filter was clogged and the solution contained gel.

Then, a film (2) having a thickness of 130 μm was produced in the same manner as in Example 1. Thereafter, the copolymer (2) was stretched 1.5 times at 135 ° C., which is Tg + 5 ° C., to obtain a stretched film (2-1).
The stretched film (2-1) had a thickness of 85 μm, a retardation of 343 nm, a birefringence of 0.00401, and a haze value of 1.8, and was a film with poor transparency. The area satisfying the phase difference of ± 3 nm after stretching and the optical axis of ± 0.5 degrees or less was 32 cm ² , and the area without uniform phase difference and optical axis unevenness was very small.

Moreover, 1.5 times of extending | stretching was performed at 155 degreeC which is Tg + 25 degreeC of a copolymer (2) using the film (2), and the stretched film (2-2) was obtained. The stretched film (2-2) had a thickness = 85 μm, a phase difference = 163 nm, a birefringence index = 0.00192, and a haze value = 0.4. Moreover, the area which satisfy | fills the phase difference +/- 3nm and optical axis +/- 0.5 degrees or less after extending | stretching was 64 cm < ² >. Transparency, uniform phase difference, and an area free from optical axis unevenness were improved, but the birefringence decreased and the phase difference was greatly reduced.

[Comparative Example 2]
In Example 1, a copolymer (3) was obtained in the same manner as in Example 1 except that 86 parts of DNM and 14 parts of norbornene (NB) were used as monomers.
The copolymer (3) has a weight average molecular weight (Mw) = 10.3 × 10 ⁴ , a molecular weight distribution (Mw / Mn) = 3.5, an intrinsic viscosity (η _inh ) = 0.64, a glass transition temperature (Tg). ) = 121 ° C. Moreover, Tg distribution was 45 degreeC. In addition, when the hydrogenation rate of the copolymer (3) was calculated | required by < ¹ > H-NMR measurement, the olefinic unsaturated bond was hydrogenated 99.9% or more. Further, when the polymer solution before the solvent removal treatment was continuously filtered in the same manner as in Example 1 and the change in the filtration rate with time was followed, the filter was not clogged after 1000 hours, and the filtration rate was It did not drop.

In the same manner as in Example 1, a 130 μm thick film (3) was prepared. Thereafter, the copolymer (3) was stretched 1.5 times at 126 ° C., which is Tg + 5 ° C., to obtain a stretched film (3-1).
The stretched film (3-1) had a thickness of 85 μm, a retardation of 325 nm, a birefringence of 0.00387, and a haze value of 4.3, and was a film with poor transparency. The area satisfying the phase difference ± 3 nm after stretching and the optical axis ± 0.5 degrees or less was 24 cm ² , and the area without uniform phase difference and optical axis unevenness was very small.

Using the cast film (3), the copolymer (3) was stretched 1.5 times at 146 ° C. which is Tg + 25 ° C. to obtain a stretched film (3-2).
The stretched film (3-2) has a thickness of 85 μm, a retardation of 102 nm, a birefringence of 0.00109, and a haze value of 0.8. The area satisfying the phase difference after stretching of ± 3 nm and the optical axis of ± 0.5 degrees or less was 56 cm ² . Although the transparency, the uniform phase difference, and the area without optical axis unevenness were improved as compared with Comparative Example 1, the birefringence decreased and the phase difference expression was greatly reduced.

[Example 2]
Other than changing the catalyst type, addition amount and hydrogenation start temperature of the hydrogenation reaction, and not using octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, which is a reaction modifier Produced a copolymer (1 ′) in the same manner as in Example 1. In the hydrogenation reaction, the obtained copolymer solution was placed in an autoclave, and 200 parts of toluene was further added. Next, 0.0251 parts of pnC ₅ H ₁₃ -Ph-COO-RuH (CO) [P (C ₆ H ₅ )] ₂ , which is a hydrogenation catalyst, is added as a reaction modifier and heated to 85 ° C. Hydrogen gas was charged into the reactor and the pressure was 10 MPa. Thereafter, the reaction was carried out at 165 ° C. for 3 hours while maintaining the pressure at 10 MPa.

The obtained copolymer (4) has a weight average molecular weight (Mw) = 6.08 × 10 ⁴ , a molecular weight distribution (Mw / Mn) = 3.8, an intrinsic viscosity (η _inh ) = 0.52, a glass transition. The temperature (Tg) was 131 ° C. Moreover, Tg distribution was 25 degreeC. Moreover, when the hydrogenation rate of the copolymer (4) was calculated | required like Example 1, the olefinic unsaturated bond was hydrogenated 99.9% or more.

Then, a film (4) having a thickness of 130 μm was produced in the same manner as in Example 1. Thereafter, at 136 ° C., which is Tg + 5 ° C. of the copolymer (4), the stretching is performed at a stretching rate = 300% / min, 1.5 times by the free uniaxial stretching method in the same manner as in Example 1, and stretching is performed. A film (4) was obtained.
The stretched film (4) had a thickness of 85 μm, a retardation of 345 nm, a birefringence of 0.00406, and a haze value of 0.1, and was confirmed to be a transparent film having no appearance defect. Moreover, the area which satisfy | fills the phase difference +/- 3nm and optical axis +/- 0.5 degrees or less after extending | stretching was 64 cm < ² >.

Industrial applicability

The cyclic olefin-based ring-opening copolymer of the present invention is excellent in heat resistance and can be suitably used for general optical applications, but it can be suitably used by processing into a film or sheet, and is stretched in the vicinity of Tg. However, since it can be processed stably without problems such as cloudiness, it is most suitable for an application requiring stretching, for example, an optical film such as a retardation plate. More specifically, the film or sheet according to the present invention, and in particular the phase difference plate, is a mobile phone, a digital information terminal, a pager, a navigation, an in-vehicle liquid crystal display, a liquid crystal monitor, a light control panel, a display for OA equipment. It can be used for various liquid crystal display elements such as displays for AV equipment, electroluminescence display elements or touch panels. It is also useful as a wave plate used in an optical disk recording / reproducing apparatus such as a CD, CD-R, MD, MO, and DVD.

Claims (7)

A cyclic olefin ring-opening copolymer comprising a structural unit represented by the following formula (1), a structural unit represented by the following formula (2), and a structural unit represented by the following formula (3): Polymer;

(In formula (1), m is 0, 1 or 2, X is independently a group represented by the formula: —CH═CH— or a group represented by the formula: —CH ₂ CH ₂ —, R ^{1 to} R ⁴ are each independently a hydrogen atom; a halogen atom; a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms which may have a linking group containing oxygen, nitrogen, sulfur or silicon; or Represents a polar group, provided that at least one of R ^{1 to} R ⁴ is a polar group and at least one of the other R ^{1 to} R ⁴ is a hydrocarbon group having 1 to 10 carbon atoms).

(In formula (2), X is independently a group represented by the formula: —CH═CH— or a group represented by the formula: —CH ₂ CH ₂ —, and R ^{5 to} R ¹⁰ are each independently hydrogen. An atom; a halogen atom; a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms which may have a linking group containing oxygen, nitrogen, sulfur or silicon; or a polar group.

(In the formula (3), n is 0, 1 or 2, X is independently a group represented by the formula: —CH═CH— or a group represented by the formula: —CH ₂ CH ₂ —, R ^{11 to} R ¹⁴ are each independently a hydrogen atom; a halogen atom; or a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms which may have a linking group containing oxygen, nitrogen, sulfur or silicon. Represents.)   2. The cyclic olefin ring-opening copolymer according to claim 1, wherein the differential differential scanning calorimetry curve of DSC shows a single peak, and the glass transition temperature (Tg) is 110 ° C. or higher.   3. The cyclic olefin-based ring-opening copolymer according to claim 1, wherein the cyclic olefin-based ring-opening copolymer has no structural unit other than the structural units represented by the formulas (1) to (3). The cyclic olefin ring-opening according to any one of claims 1 to 3, wherein the polar group in the structural unit represented by the formula (1) is a group represented by the following formula (4). Copolymer;
− (CH ₂ ) _p COOR ′ (4)
(In Formula (4), p is 0 or an integer of 1 to 5, and R ′ is a hydrocarbon group having 1 to 15 carbon atoms).   A film or sheet comprising the cyclic olefin-based ring-opening copolymer according to claim 1.   A retardation film obtained by stretching and orienting the film or sheet according to claim 5. A method for producing a phase difference plate, wherein the film or sheet according to claim 5 is stretched and oriented under a temperature condition of Tg to (Tg + 10) ° C. of the cyclic olefin copolymer contained in the film or sheet.

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