JP2003342384A - Stretched film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stretched film which excels in precision without wrinkling and ununiformity in thickness, does not cause dimensional change for a long period of time, excels in optical properties, and is useful as an optical film. <P>SOLUTION: The continuous stretched film is obtained by continuously stretching an unstretched film which has a content of a volatile component of ≤1,000 ppm and is composed of an alicyclic structure-containing polymer resin angularly in the direction at an angle of 1-50 degrees from the width direction. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretched film, and more specifically, it is excellent in accuracy without wrinkles and thickness unevenness
In addition, the present invention relates to a stretched film which has no dimensional change in the long term and is excellent in stability of optical properties.

[0002]

2. Description of the Related Art A liquid crystal display (LCD) is widely used as a flat panel display for televisions, personal computers, etc., because it has high image quality, thinness, light weight, and low power consumption. In addition, a super-twisted nematic (STN) liquid crystal having a simple matrix structure and a simple structure is used for a color liquid crystal display. However, due to elliptically polarized light based on the STN liquid crystal, the hue of the liquid crystal display is green or yellowish red. Cause As one of means for solving this problem, there has been taken a measure of using a retardation film, compensating the retardation by birefringence of STN liquid crystal, and returning elliptically polarized light to linearly polarized light.

As a method for producing this retardation film, for example, a film stretched uniaxially in the length direction or the width direction of an unstretched film has a predetermined orientation with respect to the side of the stretched film so as to have a desired orientation axis. A method is known in which the stretched film is cut so as to have an inclination angle.
However, this method has a problem that even if cutting is performed so that the maximum area is obtained, a cutting loss always occurs and the product yield is poor.

Further, in Japanese Patent Laid-Open No. 2000-9912, a film made of a plastic such as polycarbonate or polyester is uniaxially stretched in the transverse or longitudinal direction, and the left and right of the stretching direction are different from the stretching direction at different speeds. It has been proposed that the orientation axis be inclined with respect to the uniaxial stretching direction by stretching in the longitudinal or transverse direction. According to this method, the inclination angle of the orientation axis can be easily changed by controlling the stretching ratio in the longitudinal and transverse directions, and an oblique orientation film in which the orientation axis is inclined at various angles with respect to the edge can be efficiently obtained. be able to. However, the stretched film obtained by this method has wrinkles and uneven thickness, making it difficult to obtain a film with excellent accuracy.

Further, Japanese Patent Laid-Open No. 2002-86554 discloses a locus L1 of a holding means from a substantial holding start point of one end of a polymer film such as polyvinyl alcohol to a substantial holding release point, and a polymer film. The locus L2 of the holding means from the substantial holding start point to the substantial holding release point at the other end and the distance W to the two substantial holding release points are expressed by the formula (1): | L2-L1 | > 0.4W
The following describes a method for producing an optical polymer film, which satisfies the above relationship, retains the supportability of the polymer film, stretches in a state where the volatile content is 5% or more, and then shrinks while reducing the volatile content. ing. However, the film obtained by this method also has a problem that the optical characteristics change when it is used for a long period of time.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is excellent in accuracy without wrinkles and uneven thickness, and has no dimensional change in the long term and has optical characteristics. It is an object of the present invention to provide a stretched film which is useful as an optical film having excellent stability.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned object, the present inventors have found that there is no wrinkle or thickness unevenness, the accuracy is excellent, the dimensional change does not occur in the long term, and the optical characteristics are stable. In order to obtain a stretched film, it is preferable to use an unstretched film made of an alicyclic structure-containing polymer resin, and, as the unstretched film, the volatile component content is an alicyclic structure having a predetermined concentration or less. It has been found that it is preferable to obliquely stretch a resin containing polymer resin at a predetermined angle with respect to the width direction, and the present invention has been completed.

Thus, according to the present invention, an unstretched film having a volatile component content of 1000 ppm or less and made of an alicyclic structure-containing polymer resin is oriented in the direction of 1 to 50 degrees with respect to the width direction. A long stretched film obtained by continuously obliquely stretching is provided.

In the present invention, the alicyclic structure-containing polymer resin contains 10% by weight of a repeating unit having a tricyclo [4.3.0.1 ^2,5 ] decane-7,9-diyl-ethylene structure. The above is contained and the weight average molecular weight is 25,000.
0 to 80,000 and a molecular weight distribution of 1.1 to 4.0
Preferably, the resin is
[3.3.0] Containing 55 to 90% by weight of a repeating unit having an octane-2,4-diyl-ethylene structure, having a weight average molecular weight of 25,000 to 50,000 and a molecular weight distribution of 1.2. Resins of up to 3.5 are more preferred. The unstretched film is preferably obtained by melt extrusion molding.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. 1) Unstretched Film The unstretched film used in the present invention comprises an alicyclic structure-containing polymer resin. The alicyclic structure-containing polymer resin is one having an alicyclic structure in the repeating unit of the polymer resin, and has an alicyclic structure in the polymer resin and a side chain having an alicyclic structure in the main chain. Any of the polymer resins that it has can be used.

Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and the cycloalkane structure is preferable from the viewpoint of thermal stability.
The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, and more preferably 6
~ 15. When the number of carbon atoms constituting the alicyclic structure is within this range, a stretched film having excellent heat resistance and flexibility can be obtained.

The proportion of repeating units having an alicyclic structure in the polymer resin having an alicyclic structure may be appropriately selected according to the purpose of use, but is usually 50% by weight or more, preferably 70% by weight. The above is more preferable, and 90% by weight or more is more preferable. If the repeating unit having an alicyclic structure is excessively small, the heat resistance is lowered, which is not preferable. The repeating unit other than the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer resin is appropriately selected according to the purpose of use.

Specific examples of the alicyclic structure-containing polymer resin include (1) norbornene-based polymers, (2) monocyclic cycloolefin polymers, (3) cyclic conjugated diene-based polymers,
(4) Vinyl alicyclic hydrocarbon polymer, and (1) to
Examples thereof include the hydride of (4). Among these,
A hydrogenated norbornene-based polymer, a vinyl alicyclic hydrocarbon polymer and a hydride thereof are preferable because of excellent heat resistance and mechanical strength, and a hydrogenated norbornene-based polymer is more preferable.

The norbornene-based polymer used in the present invention is
It is a polymer of a monomer containing a norbornene-based monomer as a main component, such as norbornene and its derivative, tetracyclododecene and its derivative, dicyclopentadiene and its derivative, methanotetrahydrofluorene and its derivative.

Specific examples of the norbornene-based polymer include:
Ring-opening polymer of norbornene-based monomer, ring-opening copolymer of norbornene-based monomer and other monomer copolymerizable therewith, addition polymer of norbornene-based monomer, norbornene-based monomer Examples thereof include addition polymers of the body with other monomers copolymerizable therewith, and hydrides of.

Examples of the norbornene-based monomer include
Bicyclo [2.2.1] hept-2-ene (conventional name: norbornene), tricyclo [4.3.0.1 ^2,5 ] deca
3,8-diene (conventional name: dicyclopentadiene),
7,8-Benzotricyclo [4.3.0.1 ^2,5 ] dec-3-ene (conventional name: methanotetrahydrofluorene), tetracyclo [4.4.0.1 ^2,5 . 1
^[7,10 ] dodeca-3-ene (common name: tetracyclododecene), derivatives of these compounds (having a substituent on the ring), and the like. Here, examples of the substituent include an alkyl group, an alkylene group, an alkoxycarbonyl group, and a carboxyl group. Further, a plurality of these substituents may be bonded to the ring, either the same or different. The norbornene-based monomers can be used alone or in combination of two or more.

Other monomers copolymerizable with the norbornene-based monomer include, for example, bicyclo [2.2.1] hept-2-ene (common name: norbornene) and its derivatives, tetracyclo [4. 4.0.1 ^2,5 . 1 ^{7, 10} ]
Norbornene-based monomers such as dodeca-3-ene (common name: tetracyclododecene) and its derivatives; monocyclic olefins such as cyclohexene, cycloheptene, cyclooctene and their derivatives; cyclohexadiene, cycloheptadiene, etc. Conjugated diene and derivatives thereof; and the like.

The ring-opening polymer of the norbornene-based monomer and the ring-opening copolymer of the norbornene-based monomer and another monomer copolymerizable with the norbornene-based monomer are prepared by reacting the monomer in the presence of a ring-opening polymerization catalyst. (Both)
It can be obtained by polymerization.

The ring-opening polymerization catalyst to be used is, for example, a catalyst comprising a halide of a metal such as ruthenium or osmium, a sulfate or an acetylacetone compound, and a reducing agent; or a metal such as titanium, zirconium, tungsten or molybdenum. And a catalyst consisting of an acetylacetone compound and an organoaluminum compound.

The addition polymer of the norbornene-based monomer and the addition copolymer of the norbornene-based monomer and another monomer copolymerizable with the norbornene-based monomer are obtained by polymerizing the monomer in the presence of an addition polymerization catalyst. Can be obtained by As the addition polymerization catalyst, for example, a catalyst composed of a compound of a metal such as titanium, zirconium, vanadium and an organic aluminum compound can be used.

Other monomers that can be addition-copolymerized with the norbornene-based monomer include, for example, ethylene, propylene,
Carbon number 2 such as 1-butene, 1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene
To α-olefins and their derivatives; cyclobutene, cyclopentene, cyclohexene, cyclooctene, cycloolefins such as 3a, 5,6,7a-tetrahydro-4,7-methano-1H-indene and their derivatives; 4-hexadiene, 4-methyl-
Examples include non-conjugated dienes such as 1,4-hexadiene, 5-methyl-1,4-hexadiene, and 1,7-octadiene. These monomers may be used alone or in combination of 2
A combination of two or more species can be used. Of these, α-olefins are preferable, and ethylene is more preferable.

Examples of the monocyclic cyclic olefin polymer used in the present invention include addition polymers such as cyclohexene, cycloheptene and cyclooctene.

The cyclic conjugated diene polymer used in the present invention is, for example, a polymer obtained by 1,2-addition polymerization or 1,4-addition polymerization of a cyclic conjugated diene monomer such as cyclopentadiene or cyclohexadiene. Can be mentioned.

The molecular weights of the norbornene-based polymer, the monocyclic cyclic olefin polymer and the cyclic conjugated diene polymer are appropriately selected according to the purpose of use, but cyclohexane (toluene when the polymer resin is not soluble is used as the solvent. ), The weight average molecular weight (Mw) of polyisoprene or polystyrene measured by gel permeation chromatography is usually 10,000 to 100,000.
00, preferably 25,000 to 80,000, more preferably 25,000 to 50,000. When the weight average molecular weight is in such a range, the mechanical strength of the film and the moldability are highly balanced, which is preferable.

The vinyl alicyclic hydrocarbon polymer is a polymer having a repeating unit derived from vinylcycloalkene or vinylcycloalkane. As the vinyl alicyclic hydrocarbon polymer, for example, a polymer of a vinyl alicyclic hydrocarbon compound such as a cycloalkane having a vinyl group such as vinylcyclohexane, a vinyl cycloalkene having a vinyl group such as vinylcyclohexene and the hydrogen thereof. Compounds, such as aromatic partial hydrides of polymers of vinyl aromatic hydrocarbon compounds such as styrene and α-methylstyrene.

The vinyl alicyclic hydrocarbon polymer is a random copolymer of a vinyl alicyclic hydrocarbon compound or a vinyl aromatic hydrocarbon compound and another monomer copolymerizable with these monomers. It may be a copolymer such as a polymer or a block copolymer and its hydride. Examples of block copolymers include diblock, triblock, or higher multiblock or gradient block copolymers,
There is no particular limitation.

The molecular weight of the vinyl alicyclic hydrocarbon polymer is appropriately selected according to the purpose of use, but by gel permeation chromatography using cyclohexane (toluene if the polymer resin does not dissolve) as a solvent. The measured polyisoprene or polystyrene equivalent weight average molecular weight is usually 10,000 to 300,000,
When it is in the range of preferably 15,000 to 250,000, more preferably 20,000 to 200,000, the mechanical strength and molding processability of the molded article are highly balanced and suitable.

Ring-opening polymer of norbornene-based monomer, ring-opening copolymer of norbornene-based monomer with other monomer capable of ring-opening copolymerization, addition polymer of norbornene-based monomer , And hydrides of addition polymers of norbornene-based monomers and other monomers copolymerizable therewith are known hydrogenation products containing a transition metal such as nickel or palladium in a solution of these polymers. It can be obtained by adding a catalyst and hydrogenating carbon-carbon unsaturated bonds, preferably 90% or more.

The glass transition temperature of the alicyclic structure-containing polymer resin used in the present invention may be appropriately selected according to the purpose of use, but is preferably 80 ° C. or higher, more preferably 10 ° C.
It is in the range of 0 to 250 ° C. The film containing the alicyclic structure-containing polymer resin having a glass transition temperature in such a range does not cause deformation or stress during use at high temperature and is excellent in durability.

The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the alicyclic structure-containing polymer resin used in the present invention is not particularly limited, but is usually 1.0 to 10.
0, preferably 1.0 to 4.0, more preferably 1.2.
The range is from 3.5.

In the present invention, among these alicyclic structure-containing polymer resins, tricyclo [4.3.0.1] is used.
A resin containing 10% by weight or more of a repeating unit having a ^2,5 ] decane-7,9-diyl-ethylene structure is preferable, and in addition to this, bicyclo [3.3.0] octane-2,4-diyl. -A resin containing 55 to 90% by weight of a repeating unit having an ethylene structure is more preferable. By using such a resin, it is possible to obtain a stretched film which is free from dimensional change for a long period of time and is excellent in stability of optical properties.

Tricyclo in polymer resin containing alicyclic structure
Examples of the method of setting the repeating unit having a [4.3.0.1 ^2,5 ] decane-7,9-diyl-ethylene structure in the above range include, for example, tetracyclo [4.4.0.
1 ^2,5 . 1 ^7,10 ] dodec-3-ene (also known as tetracyclododecene) or a derivative thereof (having a substituent on the ring) in an amount of 10% by weight or more,
A method of polymerizing by a known metathesis ring-opening polymerization method and then hydrogenating the carbon-carbon unsaturated bond of the ring by a known method can be mentioned.

Bicyclo [3.3.0] octane-2,4-
Examples of the method for setting the repeating unit having a diyl-ethylene structure in the above range include, for example, 55 to 55 norbornene-based monomers having a structure in which a five-membered ring is bonded to a norbornene ring.
A method is known in which a monomer mixture containing 90% by weight is polymerized by a known metathesis ring-opening polymerization method, and then the carbon-carbon unsaturated bond of the ring is hydrogenated by a known method. Examples of the norbornene-based monomer having a structure in which a five-membered ring is bonded to the norbornene ring include tricyclo [4.3.0.1]
^2,5 ] deca-3,7-diene and its derivatives (having a substituent on the ring), 7,8-benzotricyclo
[4.3.0.1 ^0,5 ] deca-3-ene and its derivative are mentioned.

In the present invention, a norbornene-based monomer having a structure in which a five-membered ring structure is bonded to the norbornene ring and / or tetracyclo [4.4.0.1] is used.
^{2, 5} . A polymer obtained by ring-opening copolymerization of [ ^17,10 ] dodeca-3-ene or a derivative thereof with another monomer copolymerizable therewith can also be preferably used.

Among these, as the alicyclic structure-containing polymer resin, 10% by weight of a repeating unit having a tricyclo [4.3.0.1 ^2,5 ] decane-7,9-diyl-ethylene structure is used. The above is contained, and the weight average molecular weight is 25,
000-80,000 and the molecular weight distribution is 1.1-
A resin of 4.0 is preferable, and in addition to this, it contains 55 to 90% by weight of a repeating unit having a bicyclo [3.3.0] octane-2,4-diyl-ethylene structure, and a weight average molecular weight of 25. It is particularly preferable that the resin has a molecular weight distribution of 1.2 to 3.5 and a molecular weight distribution of 1.2 to 3.5. By using such an alicyclic structure-containing polymer resin, a stretched film having no dimensional change in the long term, excellent stability of optical properties, and extremely excellent mechanical strength even when obliquely stretched is obtained. be able to.

The unstretched film can be obtained by molding a polymer resin containing an alicyclic structure into a film. In this case, other additives and other thermoplastic resins can be added within a range that does not impair the object of the present invention.

Examples of other additives include plasticizers and deterioration inhibitors. The plasticizer is added to improve the mechanical properties of the film or to improve the drying rate. Examples of the plasticizer used include phosphoric acid ester and carboxylic acid ester.

Examples of the phosphoric acid ester include triphenyl phosphate and tricresyl phosphate. Examples of the carboxylic acid ester include phthalic acid esters such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate and diphenyl phthalate; citric acid esters such as triethyl O-acetyl citrate and tributyl O-acetyl citrate; butyl oleate. Higher fatty acid esters such as methylacetyl ricinoleate and dibutyl sebacate;
Trimet acid ester; and the like.

Examples of the deterioration inhibitor include antioxidants, peroxide decomposers, radical inhibitors, metal deactivators, acid scavengers, amines and the like. Regarding the deterioration preventing agent, JP-A-3-199201 and JP-A-5-199201
-1907073, JP-A-5-194789, JP-A-5-271471, JP-A-6-107
No. 854, etc.

The amount of addition of these other additives and other thermoplastic resins is usually 0 with respect to the alicyclic structure-containing polymer resin.
-20% by weight, preferably 0-10% by weight, more preferably 0-5% by weight.

The method for molding the alicyclic structure-containing polymer resin into a film is not particularly limited, and a known molding method can be adopted. For example, either the hot melt molding method or the solution casting method can be adopted, but it is preferable to use the hot melt molding method from the viewpoint of reducing the volatile components in the sheet.

More specifically, the hot melt molding method can be classified into a melt extrusion molding method, a press molding method, an inflation method, an injection molding method, a blow molding method, a stretch molding method and the like.
Among these, in order to obtain a stretched film excellent in mechanical strength and surface accuracy, it is preferable to use the melt extrusion molding method.

The molding conditions are appropriately selected depending on the purpose of use and the molding method, but in the case of the melt extrusion molding method, the cylinder temperature is appropriately set within the range of preferably 100 to 600 ° C, more preferably 150 to 350 ° C. To be done.

The thickness of the unstretched film can be appropriately determined according to the purpose of use of the stretched film obtained. The thickness of the film is preferably 10 to 3 from the viewpoint of obtaining a homogeneous stretched film by a stable stretching treatment.
The thickness is 00 μm, more preferably 30 to 200 μm.

2) Long stretched film The unstretched film obtained as described above is continuously obliquely stretched in the direction of an arbitrary angle θ (1 ° <θ <50 °) with respect to the width direction. Thereby, a long stretched film having an orientation axis of an angle θ with respect to the width direction of the film can be obtained.

By setting the angle θ to any value between 1 and 50 degrees, the in-plane refractive index nx in the slow axis direction, the in-plane refractive index ny in the direction perpendicular to the slow axis, and The refractive index nz in the thickness direction can be set to a desired value.

The oblique stretching method is not particularly limited as long as it is continuously stretched in the direction of 1 to 50 degrees with respect to the width direction and the orientation axis of the polymer is inclined at a desired angle. A known method can be adopted.

The stretching machine used for oblique stretching is not particularly limited, and a conventionally known tenter type stretching machine capable of applying a feeding force or a pulling force or a pulling force at different speeds in the lateral or longitudinal direction is used. can do. Further, the tenter type stretching machine includes a horizontal uniaxial stretching machine, a simultaneous biaxial stretching machine, etc., but is not particularly limited as long as it can continuously obliquely stretch a long film,
Various types of stretching machines can be used.

An example of oblique tenter stretching which can be used in the present invention is shown in FIG. As shown in FIG. 1, the unstretched film (11) obtained above was placed in a fixed direction (21).
While being conveyed to, the film is obliquely stretched using a tenter (31). The film chucked at a certain position (41, 42) in FIG. 1 has a slow speed (52L) on the left side and a position (51L).
The oblique stretching is performed by moving the right side to the position (51R) at a high speed (52R). FIG. 1 shows an example of oblique stretching at an angle θ (1 <θ <50) with respect to the width direction B, and the orientation axis is in the direction A.

The method of oblique stretching that can be used in the present invention is not limited to that shown in FIG. For example, JP-A-5
0-83482, JP-A-2-113920, JP-A-3-182701, and JP-A-2000-9.
Those described in Japanese Patent Application Laid-Open No. 912, Japanese Patent Application Laid-Open No. 2002-86554, Japanese Patent Application Laid-Open No. 2002-22944 and the like can be used.

The temperature at which the unstretched film is obliquely stretched is preferably Tg-30 ° C. to Tg + 60, where Tg is the glass transition temperature of the alicyclic structure-containing polymer resin.
C, more preferably Tg-10 ° C to Tg + 50 ° C
Temperature range. The draw ratio is usually 1.01.
˜30 times, preferably 1.01 to 10 times, more preferably 1.01 to 5 times.

The stretched film of the present invention is characterized by being substantially composed of an alicyclic structure-containing polymer resin and having a volatile component content of 1000 ppm or less, preferably 500 ppm or less. Volatile content 1000p
When it exceeds pm, the volatile component is released to the outside during use, and the stretched film undergoes dimensional change to generate internal stress. Therefore, for example, when a reflective liquid crystal display device is used, the black display is partially thinned (appears whitish).
This may cause display unevenness. A stretched film having a volatile component content in the above range is excellent in stability of optical properties in which display unevenness does not occur even when used for a long period of time.

The volatile component is a substance having a molecular weight of 200 or less and a relatively low boiling point, which is contained in a trace amount in the alicyclic structure-containing polymer resin, and examples thereof include a residual monomer and a solvent.
The content of volatile components is the total of substances having a molecular weight of 200 or less contained in the alicyclic structure-containing polymer resin in a trace amount, and quantified by analyzing the alicyclic structure-containing polymer resin by gas chromatography. You can

Examples of the method for obtaining a stretched film having a volatile component content of 1000 ppm or less include (a) a method of obliquely stretching an unstretched film having a volatile component content of 1000 ppm or less, and (b) a volatile component content. Amount is 1000
Examples include a method of reducing the content of volatile components by using an unstretched film in excess of ppm and drying during or after the oblique stretching step. Among these, in order to obtain a stretched film in which the volatile component content is further reduced,
The method (a) is preferable. In the method (a), in order to obtain an unstretched film having a volatile component content of 1000 ppm or less, it is preferable to melt-extrude a resin having a volatile component content of 1000 ppm or less.

The saturated water absorption of the stretched film of the present invention is not particularly limited, but is preferably 0.01% or less, more preferably 0.007% or less. Saturated water absorption is 0.01
If it exceeds%, dimensional change may occur in the stretched film depending on the use environment and internal stress may occur. Then, for example, when it is used in a reflective liquid crystal display device, there is a possibility that display unevenness may occur such that a black display is partially thinned (looks whitish). A stretched film having a saturated water absorption in the above range is excellent in stability of optical properties in which display unevenness does not occur even when used for a long period of time.

The stretched film of the present invention obtained as described above has an orientation axis of 1 ° to 50 ° in the width direction. Further, since it has no wrinkles and thickness unevenness, has no dimensional change over a long period of time, and has excellent stability of optical properties, it is useful as a polarizing film or a retardation film.

[0057]

EXAMPLES The present invention will be described in more detail below with reference to production examples, examples and comparative examples. In these examples
[Parts] and [%] are based on weight unless otherwise specified.
However, the present invention is not limited to the following production examples and examples.

Various physical properties were measured according to the following methods. (1) Gel permeation with molecular weight cyclohexane as a solvent
The weight average molecular weight (Mw) in terms of standard polystyrene was obtained by measurement by chromatography (GPC). (2) Molecular weight distribution The weight average molecular weight (Mw) and the number average molecular weight (Mn) in terms of standard polystyrene are measured by GPC using cyclohexane as a solvent, and the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn). (Mw / Mn) was calculated. (3) Glass transition temperature (Tg) The glass transition temperature (Tg) was measured by DSC based on JIS K7121.

(4) Hydrogenation rate The hydrogenation rate (%) of the main chain and aromatic ring of the polymer is ¹ H
-It was calculated by measuring NMR. (5) Method for measuring the amount of volatile components The volatile component content of the film was quantified by gas chromatography as the total of components having a molecular weight of 200 or less. (6) Film thickness of film The thickness was measured using an offline thickness measuring device (model: TOF-4R, manufactured by Yamabun Electric Co., Ltd.).

(7) Method of measuring saturated water absorption The saturated water absorption of the stretched film was measured according to JIS K7209. (8) Dimensional stability test of stretched film After processing the produced stretched film under the following two conditions, the dimensional change rate in the orientation axis direction was measured. The case where the dimensional change rate was within ± 0.05% was evaluated as “good”, and the case where it exceeded ± 0.05% was evaluated as “poor”. The sign is "-" for the contraction direction and "+" for the expansion direction. Condition A: Left for 30 days in an environment of temperature 30 ° C. and humidity 40% Condition B: Left for 30 days in an environment of temperature 30 ° C., humidity 80%

(8) Optical property test of stretched film The variation in the orientation angle of the produced stretched film with respect to the width direction was measured in the entire width direction (width of the tenter chuck portion was 50 mm).
Over the average value), the case of ± 0.5 degrees or less with respect to the average value was evaluated as “good”, and the case of exceeding ± 0.5 degrees was evaluated as “poor”.

(Production Example 1) Sikh dehydrated in a nitrogen atmosphere
To 500 parts of rohexane, 0.82 parts of 1-hexene and dib
Chill ether 0.15 parts, triisobutylaluminum
0.30 parts were put in a reactor at room temperature and mixed, and then the mixture was heated to 45 °
While keeping it, tricyclo [4.3.0.1 ^2,5] Deca
-3,7-diene (dicyclopentadiene, hereinafter "DC
It is abbreviated as "P". ) 80 parts, 7,8-benzotricyclo
[4.3.0.1^2,5] Dec-3-en (hereinafter referred to as "MT
Abbreviated as "F". ) 70 parts, and tetracyclo [4.
4.0.1^2,5． 1^{7, 10}] Dodeca-3-en (below
Below, it is abbreviated as "TCD". ) Consisting of norbornene
Monomer mixture and tungsten hexachloride (0.7% toluene)
Solution) and 40 parts of
It matched. Butyl glycidyl ether 1.06 in the polymerization solution
Parts and 0.52 parts of isopropyl alcohol are added to give a polymerization feel.
The medium was inactivated and the polymerization reaction was stopped.

Next, 270 parts of cyclohexane was added to 100 parts of the reaction solution containing the obtained ring-opening polymer, and 5 parts of nickel-alumina catalyst (manufactured by JGC Chemical Co., Ltd.) was used as a hydrogenation catalyst. In addition, 5 MPa due to hydrogen
After pressurizing and heating to 200 ° C with stirring,
The reaction was carried out for 4 hours to obtain a reaction solution containing 20% of hydride polymer of DCP / MTF / TCD ring-opening copolymer. After removing the hydrogenation catalyst by filtration, an antioxidant (trade name: Irganox 1010, manufactured by Ciba Specialty Chemicals) was added to and dissolved in the obtained solution (the amount of the antioxidant added was 0.1 per 100 parts of polymer
Part).

Then, using a cylindrical concentrating dryer (manufactured by Hitachi, Ltd.), the solvent cyclohexane and other volatile components were removed from the solution at a temperature of 270 ° C. and a pressure of 1 kPa or less. A hydrogenated ring-opening polymer (hydrogenated polymer) was obtained.

The copolymerization ratio of each norbornene-based monomer in the obtained hydrogenated polymer was determined by the composition of residual norbornenes in the solution after polymerization (by gas chromatography method).
Calculated from DCP / MTF / TCD = 440
The composition was almost equal to that of / 25/35. The weight average molecular weight (Mw) of this hydride was 35,000, the molecular weight distribution was 2.1, the hydrogenation rate was 99.9%, and the Tg was 134.
It was ℃.

Next, the ring-opened polymer hydride obtained above was used in a width of 5 by using a T-die type film extruder having a resin melt extruder equipped with a 65 mmφ screw.
An unstretched film A was obtained by extrusion-molding a film having a thickness of 00 mm and a thickness of 100 μm. The volatile component content of the obtained unstretched film A was 100 ppm or less, and the thickness unevenness was 3.2 μm.

(Production Example 2) 170 parts of DCP and 8-ethyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^{7, 10} ]
Dodeca-3-en (hereinafter abbreviated as "ETD") 3
Polymerization and hydrogenation reaction were carried out in the same manner as in Production Example 1 except that a norbornene-based monomer mixture consisting of 0 part was used to obtain a hydrogenated ring-opening polymer. The weight average molecular weight (Mw) of this hydrogenated ring-opening polymer was 35,000, the hydrogenation rate was 99.9%, the molecular weight distribution was 2.0, and the Tg was 10.
The temperature was 5 ° C., and then the ring-opened polymer hydride obtained above was extruded in the same manner as in Production Example 1 to give a width of 500 mm
An unstretched film B having a thickness of 100 μm was obtained. The volatile component content of the obtained unstretched film B was 100 ppm or less, and the thickness unevenness was 3.5 μm.

Example 1 Production of Stretched Film A The unstretched film A obtained in Production Example 1 was heated to 120 ° C. and introduced into a tenter stretching machine according to FIG. Horizontal uniaxial stretching (width direction) with a speed difference of
At the same time, a stretched film A was obtained by performing tensile stretching in the machine direction due to the speed difference. The angle of the orientation axis with respect to the width direction of this stretched film was 19.5 degrees on average.

Example 2 Production of Stretched Film B The unstretched film B obtained in Production Example 2 was heated to 95 ° C. and introduced into a tenter stretching machine according to FIG. A stretched film B was obtained by performing transverse uniaxial stretching (width direction) with a speed difference and stretching in the machine direction by a speed difference. The orientation axis of the stretched film B in the width direction was 45 degrees on average.

Comparative Example 1 Production of Stretched Film C A polycarbonate resin having a width of 500 mm and a thickness of 100 μm (thickness unevenness of 6.7 μm) was obtained by subjecting the polycarbonate resin to the same melt extrusion molding as in Production Example 1. Then, this film was heated to 150 ° C., introduced into a tenter stretching machine according to FIG. 1, and subjected to lateral uniaxial stretching (width direction) with a left / right moving speed having a speed difference of 5%. The stretched film C was obtained by performing tensile stretching in the direction. The orientation axis in the width direction of this stretched film C was 18.9 degrees on average.

Comparative Example 2 Production of Stretched Film D Polycarbonate film (width 500 mm, thickness 100 μm) obtained by a solution casting method as a methylene chloride solvent.
m, thickness unevenness 2.6 μm, volatile component content 30,000
(0 ppm) was used to perform continuous oblique stretching in the same manner as in Comparative Example 1, and after stretching, drying was continuously performed with hot air at 100 ° C. for 60 seconds. The volatile component content of the obtained stretched film was 5,000 ppm.

The angle of the orientation axis with respect to the width direction of the stretched films A to D obtained in Examples and Comparative Examples, the variation of the orientation axis angle, the presence or absence of wrinkles, the thickness unevenness (difference between the maximum thickness and the minimum thickness), and the volatility. Table 1 shows the evaluations of the component contents and the dimensional stability and optical property stability. In Table 1, the presence or absence of wrinkles was evaluated by visually observing the stretched film and ◯ when no wrinkles were observed, and x when no wrinkles were observed.

[0073]

[Table 1]

From Table 1, the stretched films A and B of Examples 1 and 2 have no wrinkles, and the stretched films C of Comparative Examples 1 and 2
Compared with D, there was no thickness unevenness, and it was excellent in dimensional stability and optical property stability over a long period of time.

[0075]

EFFECT OF THE INVENTION The stretched film of the present invention is excellent in accuracy without wrinkles and thickness unevenness, and has no dimensional change in the long term.
It is excellent in stability of optical properties and is useful as a retardation film. Further, since the stretched film of the present invention is long, it can be wound into a roll and stored. For example, when the stretched film of the present invention is used as a retardation plate and a (elliptical) circularly polarizing plate is produced by laminating it with a long quarter-wave plate, continuous production is possible, resulting in high productivity. Has the advantage that Further, since the stretched film of the present invention is stretched at a predetermined angle, it is not necessary to cut out obliquely to have a predetermined angle, for example,
Continuous processing such as roll-to-roll is possible.

[Brief description of drawings]

FIG. 1 is an explanatory plan view in which an unstretched film is obliquely stretched in Examples and Comparative Examples.

[Explanation of symbols]

11 ... Unstretched film 21 ... Film transport direction 31 ... tenter 41, 42 ... Chuck position 51R ... film right moving position 51L ... film left movement position 52R ... right moving speed 52L ... leftward moving speed A ... Direction of orientation axis B ... Width direction

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 45:00 C08L 45:00 65:00 65:00 F term (reference) 4F071 AA39 AA69 AF30 AH19 BA01 BB06 BB07 BC03 4F210 AA12A AF16 AG01 AH73 AM32 QA02 QC03 QG01 QG18

Claims (4)

[Claims] 1. An unstretched film having a volatile component content of 1000 ppm or less and comprising an alicyclic structure-containing polymer resin is continuously obliquely stretched in a direction of 1 to 50 degrees with respect to its width direction. A long stretched film obtained by. 2. The alicyclic structure-containing polymer resin is tricyclo [4.3.0.1 ^2,5 ] decane-7,9-diyl-
The stretched film according to claim 1, which is a resin containing 10% by weight or more of a repeating unit having an ethylene structure, having a weight average molecular weight of 25,000 to 80,000 and a molecular weight distribution of 1.1 to 4.0. . 3. The alicyclic structure-containing polymer resin further comprises bicyclo [3.3.0] octane-2,4-diyl-
55 to 90% by weight of repeating unit having an ethylene structure
Containing and having a weight average molecular weight of 25,000 to 50,000
The stretched film according to claim 2, which is a resin having a molecular weight distribution of 1.2 to 3.5. 4. The stretched film according to claim 1, wherein the unstretched film is obtained by melt extrusion molding.