KR20110009094A - Drawn film, drawn film manufacturing method, and polarizer - Google Patents

Abstract

(Rth(T)/Rth(I))

0.9
식 I) 중, Rth(T) 는, 상기 필름의 적어도 2 변을 파지한 상태에서 온도 T 에 3 분간 둔 후의 상기 필름의 λ = 590 ㎚ 에서 측정한 두께 방향의 리타데이션값이고, Rth(I) 은, 상기 필름의 λ = 590 ㎚ 에서 측정한 두께 방향의 리타데이션의 초기값이다. 또, 상기 중량 감소율은, 중량 감소율 (%) = [{(초기의 필름 중량) - (온도 T 에서 60 분간 유지한 후의 필름 중량)}/(초기의 필름 중량)] × 100 에 의해 구해지는 것이다.The film formed by the solution casting method having an initial value of 30 nm or more in the retardation in the thickness direction is stretched at a temperature T satisfying the following formula I), and measured by TG-DTA at the temperature T. A stretched film, characterized in that a weight loss rate of about 60 minutes is 5% or less.
Equation I) 0.2

(Rth (T) / Rth (I))

0.9
In formula I), Rth (T) is a retardation value of the thickness direction measured at (lambda) = 590 nm of the said film after leaving it for 3 minutes in temperature T in the state which hold | maintained at least 2 sides of the said film, and Rth (I ) Is the initial value of the retardation in the thickness direction measured at λ = 590 nm of the film. In addition, the said weight reduction rate is calculated | required by weight reduction rate (%) = [{(initial film weight)-(film weight after holding for 60 minutes at temperature T)} / (initial film weight)] x100 .

Description

Stretched film, manufacturing method of stretched film, and polarizing plate {DRAWN FILM, DRAWN FILM MANUFACTURING METHOD, AND POLARIZER}

This invention relates to a stretched film, a manufacturing method of a stretched film, and a polarizing plate.

The polarizing plate is manufactured by bonding the protective film which has a cellulose triacetate as a main component to the both sides of the polarizing film which orientate-adsorbed iodine or a dichroic dye to polyvinyl alcohol normally. Cellulose triacetate is widely used as the protective film for polarizing plates mentioned above by the characteristics, such as high toughness, flame retardancy, and optical isotropy (low retardation value). The liquid crystal display device is comprised from a polarizing plate, a liquid crystal cell, etc. As described in Patent Literature 1, a liquid crystal display device having a high display quality is realized by inserting an optical compensation sheet (also referred to as an optical compensation film) between a polarizing plate and a liquid crystal cell.

As a material of a protective film, in addition to the said cellulose triacetate, a cyclic olefin resin film is proposed.

As a manufacturing method of these protective films, the solution casting method which makes the dope which made resin and another additive a solution the casting | flow_spread on a support body is known. However, in the solution casting method, when the solvent is volatilized, the solvent is volatilized from the surface on the film, so that the molecular chains overlap, thereby forming a state in which the molecules are stacked. For this reason, unlike melt film forming, there existed a problem that the retardation (Rth) of thickness direction tends to be expressed high.

On the other hand, although the invention which specified extending | stretching conditions at the time of manufacturing a functional film is disclosed, for example in patent documents 2 and 3, it searches for the temperature condition which actively lowers Rth of the film formed by the solution casting method, or a film There is no mention of the art of including an additive of to set the optimum temperature and obtaining a functional film having the desired optical properties.

Japanese Unexamined Patent Publication No. Hei 8-50206 Japanese Laid-Open Patent Publication 2006-235085 Japanese Patent Laid-Open No. 5-150115

As described above, in general, in the solution casting method, the molecular chain stacking effect when the solvent is volatilized causes overlapping of the molecular chains, which tends to increase Rth. This point is the point which differs most from molten film forming, and the film obtained by melt film forming has the value of the initial value of Rth near zero. Moreover, in general, the stretching of the polymer is often performed in the vicinity of the glass transition temperature (Tg) in view of the good efficiency of the optical property expressability. However, the crystalline polymer may increase in Rth on the contrary even if it is stretched in the vicinity of Tg.

By raising the stretching temperature, the polymer approaches the molten state and the Rth may be reduced, but crystallization proceeds depending on the stretching temperature, and the Rth is increased. If the temperature is set to a higher temperature and is not crystallized, decomposition of the polymer is initiated beyond the thermal decomposition point of the polymer. When the polymer decomposes, free acid is generated or the film color taste changes, so stretching at a temperature below the decomposition point is very important.

Moreover, when an additive is used, the volatilization property of an additive may become large with respect to film temperature depending on the volatility of the additive, and the intended optical characteristic may not be acquired.

As described above, depending on the type, structure, and additives of the polymer, the expression properties of the optical properties vary, and the optimum temperature range cannot be determined only by the Tg or the crystallization temperature.

Therefore, in the present invention, the polymer has no relationship with Tg or crystallinity, and the temperature at which the Rth initially expressed by the solution film forming method is lowered to the intended Rth and the weight reduction rate of the film are small, and the volatilization property is low. It was found out that arbitrary optical properties can be expressed by intentionally selecting a small temperature and thermal stretching.

That is, an object of the present invention is to provide a stretched film obtained by stretching a film formed by a solution casting method, wherein the stretched film has a lower Rth value than the initial Rth value and a smaller weight reduction rate.

The said subject was solved by the following structures.

1. The film formed by the solution casting method having an initial value of 30 nm or more in the retardation in the thickness direction is stretched at a temperature T that satisfies the following formula I), and is a TG-DTA at the temperature T. The stretched film for 60 minutes measured by 5% or less of the stretched film characterized by the above-mentioned.

(Rth(T)/Rth(I))

0.9Equation I) 0.2

(Rth (T) / Rth (I))

0.9

In formula I), Rth (T) is the retardation value of the thickness direction measured at (lambda) = 590 nm of the said film after leaving at temperature T for 3 minutes in the state which hold | maintained at least 2 sides of the said film, Rth (I) is an initial value of the retardation of the thickness direction measured by (lambda) = 590 nm of the said film. In addition, the said weight reduction rate is calculated | required by weight reduction rate (%) = [{(initial film weight)-(film weight after holding for 60 minutes at temperature T)} / (initial film weight)] x100 .

2. The stretched film of 1 whose optical characteristic after extending | stretching satisfy | fills the following conditions.

Rth/Re＋0.5

5 (식 중, Rth 는 λ = 590 ㎚ 에서 측정한 두께 방향의 리타데이션값이고, Re 는 λ = 590 ㎚ 에서 측정한 면내의 리타데이션값이다)1.75

Rth / Re + 0.5

5 (wherein Rth is a retardation value in the thickness direction measured at λ = 590 nm, and Re is an in-plane retardation value measured at λ = 590 nm)

3. Said stretched film of 1 or 2 whose said film is cyclic olefin resin film.

4. Said film is said stretched film as described in said 1 or 2 which has a C2-C4 acyl substituent and consists of cellulose resin whose substitution degree of acyl group is 2.1-2.7.

5. The stretched film according to the above 4, wherein the film has an acyl substituent having 2 to 4 carbon atoms and the substitution degree of the acyl group is made of a cellulose resin having 2.3 to 2.6.

Re

100 ㎚, 50 ㎚

Rth

300 ㎚ 를 만족하는 상기 1∼5 중 어느 하나에 기재된 연신 필름. (Re 는 λ = 590 ㎚ 에서 측정한 면내의 리타데이션값이고, Rth 는 λ = 590 ㎚ 에서 측정한 두께 방향의 리타데이션값이다)6. Optical properties, 25 nm

Re

100 nm, 50 nm

Rth

The stretched film in any one of said 1-5 which satisfy | fills 300 nm. (Re is the in-plane retardation value measured at λ = 590 nm, and Rth is the retardation value in the thickness direction measured at λ = 590 nm)

Re

70 ㎚, 90 ㎚

Rth

120 ㎚ 를 만족하는 상기 1∼5 중 어느 하나에 기재된 연신 필름. (Re 는 λ = 590 ㎚ 에서 측정한 면내의 리타데이션값이고, Rth 는 λ = 590 ㎚ 에서 측정한 두께 방향의 리타데이션값이다)7. Optical property, 50 nm

Re

70 nm, 90 nm

Rth

The stretched film in any one of said 1-5 which satisfy | fills 120 nm. (Re is the in-plane retardation value measured at λ = 590 nm, and Rth is the retardation value in the thickness direction measured at λ = 590 nm)

8. The stretched film in any one of said 1-7 in which the said film contains a retardation regulator.

9. Polarizing plate which has polarizer and two protective films on both sides of this polarizer, At least 1 of these two protective films is the stretched film in any one of said 1-8.

10. It has a process of extending | stretching the film formed by the solution casting | flow_spreading method which has the initial value whose retardation of thickness direction is 30 nm or more at the temperature T which satisfy | fills following formula I), and TG- in the temperature T 60 minutes of weight loss measured by DTA is 5% or less, The manufacturing method of the stretched film characterized by the above-mentioned.

(Rth(T)/Rth(I))

0.9Equation I) 0.2

(Rth (T) / Rth (I))

0.9

In formula I), Rth (T) is a retardation value of the thickness direction measured at (lambda) = 590 nm of the said film after leaving it for 3 minutes in temperature T in the state which hold | maintained at least 2 sides of the said film, and Rth (I ) Is the initial value of the retardation in the thickness direction measured at λ = 590 nm of the film. In addition, the said weight reduction rate is calculated | required by weight reduction rate (%) = [{(initial film weight)-(film weight after holding for 60 minutes at temperature T)} / (initial film weight)] x100 .

According to this invention, the stretched film obtained by extending | stretching the film formed by the solution casting method can provide the stretched film whose Rth value after extending | stretching is lower than the initial Rth value, and whose weight loss rate is small.

Moreover, this stretched film is equipped with the optical characteristic useful as each functional film. Moreover, the polarizing plate rich in durability using the stretched film can be provided.

Carrying out the invention  Best form for

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

In addition, in this specification, description of "(numerical value 1)-(numerical value 2)" "(numerical value 1)-(numerical value 2)" shows the meaning of "(numerical value 1) or more (numerical value 2) or less".

The stretched film of this invention is made by extending | stretching the film formed by the solution casting | flow_spreading method which has the initial value whose retardation of the thickness direction is 30 nm or more at temperature T which satisfy | fills following formula I), and to the temperature T It is characterized by the weight loss rate for 60 minutes measured by TG-DTA in 5% or less.

(Rth(T)/Rth(I))

0.9Equation I) 0.2

(Rth (T) / Rth (I))

0.9

In formula I), Rth (T) is a retardation value of the thickness direction measured at (lambda) = 590 nm of the said film after leaving it for 3 minutes in temperature T in the state which hold | maintained at least 2 sides of the said film, and Rth (I ) Is the initial value of the retardation in the thickness direction measured at λ = 590 nm of the film. In addition, the said weight reduction rate is calculated | required by weight reduction rate (%) = [{(initial film weight)-(film weight after holding for 60 minutes at temperature T)} / (initial film weight)] x100 .

In the present invention, any film can be used as long as it is a film formed by a solution casting method, but it is preferably a cyclic olefin resin film (also referred to as a cyclic polyolefin film) or a cellulose resin film.

The cyclic polyolefin film contains at least cyclic olefin resin (also called ring polyolefin resin or cyclic polyolefin). The cellulose resin film contains at least a cellulose resin. Cyclic olefin resin and cellulose resin are demonstrated below.

(Cyclic polyolefin resin)

In this invention, cyclic polyolefin type resin represents the polymer resin which has a cyclic polyolefin structure.

Examples of the polymer resin having a cyclic olefin structure that can be used in the present invention include (1) a norbornene-based polymer, (2) a polymer of a cyclic olefin of a single ring, (3) a polymer of a cyclic conjugated diene, and (4) Vinyl alicyclic hydrocarbon polymers, and hydrides of (1) to (4). The polymer resin preferably used in the present invention is an addition (co) polymer cyclic polyolefin containing at least one or more repeating units represented by the following General Formula (7) and, if necessary, the repeating represented by General Formula (6). It is an addition (co) polymer cyclic polyolefin which further contains at least 1 or more types of units. Moreover, the ring-opening (co) polymer containing at least 1 type of cyclic repeating unit represented by General formula (8) can also be used preferably.

[Formula 1]

In formula, m represents the integer of 0-4. R ¹ ~R ⁶ represents a hydrogen atom or a hydrocarbon group of 1 to 10 carbon ^{atoms, X 1 ~X 3, Y 1} ~Y 3 Is a hydrogen atom, a hydrocarbon group of 1 to 10 carbon atoms, a halogen atom, a hydrocarbon group of 1 to 10 carbon atoms substituted with a halogen atom,-(CH ₂ ) _n COOR ¹¹ ,-(CH ₂ ) _n OCOR ¹² ,-(CH ₂ ) _n NCO,-(CH ₂ ) _n NO ₂ ,-(CH ₂ ) _n CN,-(CH ₂ ) _n CONR ¹³ R ¹⁴ ,-(CH ₂ ) _n NR ¹³ R ¹⁴ ,-(CH ₂ ) _n OZ, -(CH ₂ ) _n W, or X ¹ And Y ¹ or X ² and Y ² or X ³ (-CO) ₂ O consisting of and Y ³ , (-CO) ₂ NR ¹⁵ Indicates. In addition, R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ Is a hydrogen atom, a hydrocarbon group of 1 to 20 carbon atoms, Z is a hydrocarbon group or a hydrocarbon group substituted by halogen, W is SiR ¹⁶ _p D _{3 -p} (R ¹⁶ is a hydrocarbon group of 1 to 10 carbon atoms, D is a halogen atom, -OCOR ¹⁵ or -OR ¹⁶ , p represents an integer of 0 to 3), n represents an integer of 0 to 10.

By introducing a minute a large polar functional group in the substituents of ^{X 1 ~X 3, Y 1 ~Y} 3, can increase the thickness direction retardation (Rth) of the film, and possible to increase the expression of the in-plane retardation (Re) . The Re value can be enlarged by extending | stretching in the film forming process of the film with large Re expressionability.

As the norbornene-based addition (co) polymer, those disclosed in JP-A-10-7732, JP-A-2002-504184, US2004229157 A1 specification, or International Publication No. 2004/070463 A1 pamphlet can be used. have. It is obtained by addition-polymerizing norbornene-type polycyclic unsaturated compounds. Moreover, if necessary, a norbornene-type polycyclic unsaturated compound and conjugated dienes, such as ethylene, propylene, butene, butadiene, and isoprene; Non-conjugated dienes such as ethylidene norbornene; The linear diene compounds, such as acrylonitrile, acrylic acid, methacrylic acid, maleic anhydride, acrylic acid ester, methacrylic acid ester, maleimide, vinyl acetate, and vinyl chloride, can also be addition-polymerized. A commercial item can also be used as this norbornene-type addition (co) polymer. Specifically, it is marketed under the trade name of Apel from Mitsui Chemicals Co., and glass transition temperature (Tg) is different, for example, APL8008T (Tg 70 degreeC), APL6013T (Tg 125 degreeC), APL6015T (Tg 145 degreeC), etc. There is a grade. Pellets, such as TOPAS8007, 6013, and 6015, are available from Polyplastics. In addition, Appear3000 is released from Ferrania.

Norbornene-based polymer hydrides are disclosed in Japanese Patent Application Laid-Open No. Hei 1-240517, Japanese Patent Laid-Open No. 7-196736, Japanese Patent Laid-Open No. 60-26024, Japanese Patent Laid-Open No. 62-19801, and Japanese Laid-Open Patent Publication. As disclosed in Japanese Patent Laid-Open Publication No. 2003-1159767 or Japanese Laid-Open Patent Publication No. 2004-309979, those produced by hydrogenation of a polycyclic unsaturated compound after addition polymerization or metathesis ring-opening polymerization can be used. In the norbornene-based polymer used in the present invention, R ⁵ to R ⁶ are a hydrogen atom or -CH ₃ Are preferred, X ³ , and Y ³ Silver hydrogen atom, Cl, -COOCH ₃ This is preferable and other groups are suitably selected. A commercial item can also be used for this norbornene-type resin, Specifically, it is marketed under the brand name of Arton G or Aton F from JSR, Zeonor ZF14, from Nippon Xeon It is marketed under the brand names ZF16, Zeonex 250 or Zeonex 280, and can be used.

As for the said cyclic polyolefin type resin which can be used by this invention, it is preferable that the mass mean molecular weight (Mw) measured by the gel permeation chromatography (GPC) is 5,000 to 1,000,000 in polystyrene molecular weight conversion, and it is 10,000 to 500,000. It is more preferable, and it is still more preferable that it is 50,000-300,000. Moreover, it is preferable that molecular weight distribution (Mw / Mn; Mn is the number average molecular weight measured by GPC) is 10 or less, More preferably, it is 5.0 or less, More preferably, it is 3.0 or less. It is preferable that glass transition temperature (Tg; measured by DSC) is 50-350 degreeC, More preferably, it is 80-330 degreeC, More preferably, it exists in the range of 100-300 degreeC.

(Cellulose-based resin)

Cellulose-based resin that can be used in the present invention is not particularly limited as long as the degree of substitution of all acyl groups is 2.0 to 2.95. A cellulose ester is preferable and, as for cellulose resin, a cellulose acylate is more preferable. As a raw material cellulose of a cellulose resin, there exist a cotton linter, a wood pulp (softwood pulp, a softwood pulp), etc., The cellulose water obtained from any raw material cellulose can be used, and you may mix and use as needed. For detailed descriptions of these raw celluloses, see, for example, Maruzawa, Uda, "Plastic Material Course (17) Fibrin-Based Resin," Nigangan Shimbun (Issued in 1970) or Invention Association Publication No. 2001-1745 ( Cellulose described in pages 7 to 8) can be used.

(Cellulose ester)

It describes in detail about the cellulose ester which can be used preferably for this invention. The glucose unit which (beta) -1,4 couple | bonded which comprises a cellulose has free hydroxyl group in 2, 3, and 6 positions. A cellulose ester is a polymer (polymer) which esterified some or all of these hydroxyl groups by the acyl group of 2 or more carbon atoms. Acyl substitution degree means the ratio (100% esterification is substitution degree 1) in which the hydroxyl group of the cellulose located in 2nd, 3rd, and 6th positions is esterified.

As for all acyl substitution degree, ie, DS2 + DS3 + DS6, 2.1-2.9 are preferable, More preferably, it is 2.1-2.7, Especially preferably, it is 2.3-2.6. The DS6 / (DS2 + DS3 + DS6) is preferably 0.08 to 0.66, more preferably 0.15 to 0.60, still more preferably 0.20 to 0.45. Here, DS2 is the substitution degree by the acyl group of the hydroxyl group of 2-position of a glucose unit (henceforth "acyl substitution degree of 2-position"), DS3 is the substitution degree by the acyl group of the hydroxyl group of 3-position (hereinafter, "3 DS6 is a substitution degree by the acyl group of the hydroxyl group of 6-position (henceforth "acyl substitution degree of 6-position"). In addition, DS6 / (DS2 + DS3 + DS6) is a ratio of the 6-position acyl substitution degree with respect to all acyl substitution degree, and is also called "the 6-position acyl substitution rate."

One type of acyl group to replace may be sufficient, or 2 or more types of acyl groups may be substituted. As cellulose resin, what has a C2-C4 acyl group as a substituent is preferable. As the acyl group having 2 to 4 carbon atoms, a propionyl group or a butyryl group is preferable. When using two or more types of acyl groups, it is preferable that one is an acetyl group. When the sum of the substitution degree by the acetyl group of the hydroxyl group of 2nd, 3rd and 6th position is DSA, and the sum of the substitution degree by the propionyl group or butyryl group of the hydroxyl group of 2nd, 3rd and 6th position is DSB, , DSA + DSB is preferably 2.0 to 2.9. As for the value of DSA + DSB, it is more preferable that it is 2.3-2.8, and the value of DSB is 0.10-1.70. More preferably, the value of DSA + DSB is 2.40-2.50 and the value of DSB is 0.5-1.2. By setting the values of DSA and DSB in the above ranges, a film having a small change in Re value and Rth value due to environmental humidity can be obtained, which is preferable.

In addition, it is preferable that 28% or more of the DSB is a substituent of the 6-position hydroxyl group, more preferably 30% or more is a substituent of the 6-position hydroxyl group, more preferably 31% or more is a substituent of the 6-position hydroxyl group, and 32% It is especially preferable that the above is a substituent of a 6-position hydroxyl group. By these cellulose esters, the solubility with which preferable solubility can be manufactured can be manufactured, and especially in non-chlorine organic solvent, manufacture of a favorable solution is attained. In addition, it is possible to prepare a solution having a low viscosity and good filterability.

The acyl group having 2 or more carbon atoms of the cellulose ester may be an aliphatic group or an aryl group, and is not particularly limited. They are alkylcarbonyl ester, alkenylcarbonyl ester, aromatic carbonyl ester, aromatic alkylcarbonyl ester, etc. of cellulose, for example, and may have group substituted further, respectively. Preferred examples thereof include propionyl group, butanoyl group, heptanoyl group, hexanoyl group, octanoyl group, decanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, hexadecanoyl group, octadecanoyl group, Isobutanoyl group, tert-butanoyl group, cyclohexanecarbonyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group, etc. are mentioned. Among these, propionyl group, butanoyl group, dodecanoyl group, octadecanoyl group, tert-butanoyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group and the like are more preferable, and particularly preferably propionyl Group, butanoyl group.

In the acylation of cellulose, when an acid anhydride or an acid chloride is used as an acylating agent, as an organic solvent which is a reaction solvent, an organic acid, for example, acetic acid, methylene chloride, etc. are used.

As the catalyst, when the acylating agent is an acid anhydride, a protic catalyst such as sulfuric acid is preferably used, and when the acylating agent is an acid chloride (for example, CH ₃ CH ₂ COCl), a basic compound is used.

The most common method of industrial synthesis of mixed fatty acid esters of cellulose is a method of acylating cellulose with mixed organic acid components comprising fatty acids (acetic acid, propionic acid, valeric acid, etc.) corresponding to acetyl groups and other acyl groups or their acid anhydrides. .

The cellulose ester which can be used for this invention can be synthesize | combined, for example by the method of Unexamined-Japanese-Patent No. 10-45804.

(additive)

The film of this invention may contain the additive. An additive is demonstrated below.

As an additive, the low molecular weight additive, high molecular weight additive, etc. which are well-known as an additive of a cellulose acylate film and a cyclic polyolefin film can be employ | adopted widely, for example.

(Low molecular weight additives)

It is preferable to contain at least 1 sort (s) of the film of this invention as an additive in the additive represented by following General formula (1)-(5).

[Formula 2]

(3)

First, the additive of General formula (1) and (2) is demonstrated.

In the general formula (1), R ¹ represents an alkyl group or an aryl group, and R ² and R ³ Each independently represents a hydrogen atom, an alkyl group or an aryl group. Moreover, it is especially preferable that the sum total of carbon number of R <^1> , R <^2> and R < ³ > is 10 or more. In addition, in General Formula (2), R ⁴ and R ⁵ Each independently represents an alkyl group or an aryl group. Moreover, the sum total of the number of carbon atoms of R <^4> and R <^5> is ten or more, and an alkyl group and an aryl group may have a substituent, respectively. As a substituent, a fluorine atom, an alkyl group, an aryl group, an alkoxy group, a sulfone group, and a sulfonamide group are preferable, and an alkyl group, an aryl group, an alkoxy group, a sulfone group, and a sulfonamide group are especially preferable. In addition, the alkyl group may be linear, branched, or cyclic, and preferably has 1 to 25 carbon atoms, more preferably 6 to 25, more preferably 6 to 20 (eg, methyl, Ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, amyl, isoamyl, t-amyl, hexyl, cyclohexyl, heptyl, octyl, bicyclooctyl, nonyl, adamantyl, decyl, t-octyl, Undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, didecyl) are particularly preferred. The aryl group preferably has 6 to 30 carbon atoms, and particularly preferably 6 to 24 carbon atoms (eg, phenyl, biphenyl, terphenyl, naphthyl, binaphthyl, triphenylphenyl).

Details of these additives are described in Japanese Unexamined Patent Publication No. 2005-139304.

Next, the additive of General formula (3), (4), (5) is demonstrated.

In formula (3), R ¹¹ represents an aryl group. R ¹² and R ¹³ each independently represent an alkyl group or an aryl group, and at least one is an aryl group. In addition, the alkyl group and the aryl group may each have a substituent.

In formula (4), R <^21> , R <^22> and R <^23> respectively independently represents an alkyl group. Moreover, each alkyl group may have a substituent.

In formula (5), R ³¹ , R ³² , R ³³ and R ³⁴ Represents a hydrogen atom, a substituted or unsubstituted aliphatic group, or a substituted or unsubstituted aromatic group, respectively. X ³¹ , X ³² , X ³³ and X ³⁴ Is divalent formed from at least one group selected from the group consisting of a single bond, -CO- and NR ^35- (R ³⁵ represents a substituted or unsubstituted aliphatic group or a substituted or unsubstituted aromatic group), respectively. It represents a linking group. a, b, c and d are integers of 0 or more, and a + b + c + d is 2 or more. Z <^31> represents (a + b + c + d) valence organic group (except having a ring type).

Details of these additives are described in Japanese Patent Laid-Open Nos. 2007-272177 to [0075] to [0085].

(Retardation adjustment agent)

The stretched film of this invention may contain the retardation regulator. From the viewpoint of raising the (Rth / Re) value, a compound having one or more aromatic rings is preferable, a compound having 2 to 15 aromatic rings is more preferable, and a compound having 3 to 10 aromatic rings is more preferable. Do. It is preferable that each atom other than the aromatic ring in the compound is a configuration close to the same plane as the aromatic ring, and when having a plurality of aromatic rings, the aromatic rings are also preferably arranged close to the same plane. Moreover, in order to raise a Rth value selectively, it is preferable that the presence state in the film of an additive exists in the direction parallel to a film plane. As a specific example of such a compound, it describes, for example as "retardation increasing agent" on pages 6-38 of Unexamined-Japanese-Patent No. 2006-235483, These can be used suitably, Especially, the compound C of the following structure Particularly preferred.

[Formula 4]

(High molecular weight additives)

The polymer additive is selected from polyester polymers, styrene polymers and acrylic polymers and copolymers thereof, and aliphatic polyesters, aromatic polyesters, acrylic polymers and styrene polymers are preferable. Moreover, it is preferable to contain at least 1 sort (s) of polymer which has negative intrinsic birefringence, such as a styrene polymer and an acryl-type polymer.

(Polyester-Based Polymer)

The polyester polymer used in the present invention is a mixture of aliphatic dicarboxylic acid having 2 to 20 carbon atoms and aromatic dicarboxylic acid having 8 to 20 carbon atoms, aliphatic diol having 2 to 12 carbon atoms and alkyl ether having 4 to 20 carbon atoms. It is preferable that it is obtained by reaction with at least 1 or more types of diols chosen from diol and C6-C20 aromatic diol. The both ends of the reactants may be the reactants as they are, and may be reacted with monocarboxylic acids, monoalcohols or phenols to carry out so-called terminal sealing. This terminal sealing is especially effective from the point of preservation | storage etc., in order not to contain free carboxylic acids. The dicarboxylic acid used for the polyester-based polymer is preferably an aliphatic dicarboxylic acid residue having 4 to 20 carbon atoms or an aromatic dicarboxylic acid residue having 8 to 20 carbon atoms.

Examples of the aliphatic dicarboxylic acid having 2 to 20 carbon atoms that are preferably used in the present invention include oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, pimeric acid, and suveric acid. And azelaic acid, sebacic acid, dodecanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid.

Moreover, as aromatic dicarboxylic acid having 8 to 20 carbon atoms, phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid , 2,8-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and the like.

Among these, preferred aliphatic dicarboxylic acids include malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, and 1,4-cyclohexanedicarboxylic acid. As aromatic dicarboxylic acid, phthalic acid, terephthalic acid, isophthalic acid, 1, 5- naphthalenedicarboxylic acid, and 1, 4- naphthalenedicarboxylic acid are preferable. Particularly preferably, the aliphatic dicarboxylic acid component is succinic acid, glutaric acid, adipic acid, and the aromatic dicarboxylic acid is phthalic acid, terephthalic acid, isophthalic acid.

Although the above-mentioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid are used in combination of each at least 1 type, the combination is not specifically limited, It does not matter even if each component combines several types.

The diol or aromatic ring-containing diol used for the high molecular weight additive is selected from, for example, aliphatic diols having 2 to 20 carbon atoms, alkyl ether diols having 4 to 20 carbon atoms and aromatic ring containing diols having 6 to 20 carbon atoms.

Examples of the aliphatic diol having 2 to 20 carbon atoms include alkyldiols and alicyclic diols. Examples thereof include ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1, 3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentylglycol), 2,2- Diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3propanediol (3,3-dimethylolheptane), 3-methyl-1, 5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1 , 9-nonanediol, 1,10-decanediol, 1,12-octadecanediol and the like, and these glycols are used as one kind or a mixture of two or more kinds.

Preferred aliphatic diols include ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4- Butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and particularly preferably ethane Diol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1, 4-cyclohexanediol and 1,4-cyclohexanedimethanol.

The alkyl ether diol having 4 to 20 carbon atoms is preferably polytetramethylene ether glycol, polyethylene ether glycol, polypropylene ether glycol and combinations thereof. Although the average polymerization degree is not specifically limited, Preferably it is 2-20, More preferably, it is 2-10, Furthermore, it is 2-5, Especially preferably, it is 2-4. Examples of these typically available commercially available polyetherglycols include Carbowax resin, Pluronics resin and Niax resin.

Although it does not specifically limit as C6-C20 aromatic diol, Bisphenol A, 1,2-hydroxybenzene, 1, 3-hydroxybenzene, 1, 4- hydroxybenzene, 1, 4- benzene dimethanol is mentioned. And bisphenol A, 1,4-hydroxybenzene, and 1,4-benzenedimethanol.

It is especially preferable that the terminal is a high molecular weight additive sealed with an alkyl group or an aromatic group. This is a factor which is effective against deterioration with time at high temperature, high humidity by protecting a terminal by a hydrophobic functional group, and exhibits the role which delays the hydrolysis of an ester group.

It is preferable to protect with a monoalcohol residue or a monocarboxylic acid residue so that both ends of a polyester additive may not become a carboxylic acid or an OH group.

In this case, as monoalcohol, a substituted or unsubstituted monoalcohol having 1 to 30 carbon atoms is preferable, and methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, isopentanol, hexanol, isohexanol, Cyclohexyl alcohol, octanol, isooctanol, 2-ethylhexyl alcohol, nonyl alcohol, isononyl alcohol, tert-nonyl alcohol, decanol, dodecanol, dodecahexanol, dodecaoctanol, allyl alcohol, oleyl alcohol Aliphatic alcohols, such as benzyl alcohol, and substituted alcohols, such as 3-phenylpropanol, etc. are mentioned.

Terminal sealing alcohols that can be preferably used are methanol, ethanol, propanol, isopropanol, butanol, isobutanol, isopentanol, hexanol, isohexanol, cyclohexyl alcohol, isooctanol, 2-ethylhexyl alcohol, isononyl Alcohols, oleyl alcohol, benzyl alcohol, in particular methanol, ethanol, propanol, isobutanol, cyclohexyl alcohol, 2-ethylhexyl alcohol, isononyl alcohol, benzyl alcohol.

Moreover, when sealing with a monocarboxylic acid residue, the monocarboxylic acid used as a monocarboxylic acid residue has a C1-C30 substituted and unsubstituted monocarboxylic acid. Aliphatic monocarboxylic acid may be sufficient as these and aromatic ring containing carboxylic acid may be sufficient as them. When describing preferable aliphatic monocarboxylic acid, acetic acid, propionic acid, butanoic acid, caprylic acid, capronic acid, decanoic acid, dodecanoic acid, stearic acid, and oleic acid are mentioned, As an aromatic ring containing monocarboxylic acid, Examples include benzoic acid, p-tert-butylbenzoic acid, p-tert-amylbenzoic acid, orthotoluic acid, metatoluic acid, paratoluic acid, dimethylbenzoic acid, ethylbenzoic acid, normalpropylbenzoic acid, aminobenzoic acid, acetoxybenzoic acid, and the like. These can use 1 type (s) or 2 or more types, respectively.

The synthesis of such additives is carried out by thermal melting condensation by the polyesterification reaction or transesterification reaction of the dicarboxylic acid with diol and / or the terminal encapsulation monocarboxylic acid or monoalcohol by a conventional method, or these acids. It can be synthesize | combined easily by any of the interfacial condensation method of the acid chloride and glycols. These polyester additives are described in detail in Murai Koichi horseshoe "Theory and Application of Additives" (Saiishiba, Inc., first edition issued on March 1, 1973). Japanese Unexamined Patent Application Publication Nos. Hei 05-155809, Japanese Unexamined Patent Publication No. 05-155810, Japanese Unexamined Patent Application Publication No. 5-197073, Japanese Unexamined Patent Application Publication No. 2006-259494 and Japanese Unexamined Patent Application Publication No. 07-330670 The material described in each of Unexamined-Japanese-Patent No. 2006-342227, Unexamined-Japanese-Patent No. 2007-003679, etc. can also be used.

Although the specific example of the polyester polymer which can be used by this invention is described below, it is not limited to these.

In Table 1, PA is phthalic acid, TPA is terephthalic acid, IPA isophthalic acid, AA is adipic acid, SA is succinic acid, 2,6-NPA is 2,6-naphthalenedicarboxylic acid, 2 , 8-NPA is 2,8-naphthalenedicarboxylic acid, 1,5-NPA is 1,5-naphthalenedicarboxylic acid, 1,4-NPA is 1,4-naphthalenedicarboxylic acid, 1,8-NPA has shown 1,8- naphthalenedicarboxylic acid, respectively.

The polyester polymer is preferably a number average molecular weight of 700 to 10000, more preferably a number average molecular weight of 800 to 8000, still more preferably a number average molecular weight of 800 to 5000, and particularly preferably a number average molecular weight of 1000 to 5000. By setting it as such a range, it is excellent in compatibility.

(Styrene polymer and acrylic polymer)

As the additive, a compound (styrene polymer) having a structure represented by the following general formula (9) or a compound (acrylic polymer) having a structure represented by the following general formula (10) is also preferable.

[Chemical Formula 5]

{In General Formula (9) and (10), R ⁴¹ to R ⁴⁸ Each independently represents a hydrogen atom; Halogen atom; A hydrocarbon group having 1 to 30 carbon atoms, which may have a linking group containing an oxygen atom, a sulfur atom, a nitrogen atom or a silicon atom; Or a polar group, R ⁴⁴ May all be the same atom or contribution, and each may be a different atom or contribution, and combine with each other to form a carbon ring or a heterocyclic ring (these carbon rings and heterocycles may be monocyclic or different rings may be condensed to form a polycyclic structure) May be formed.}

-메틸스티렌, β-메틸스티렌, p-메틸스티렌 등의 알킬 치환 스티렌류 ; 4-클로로스티렌, 4-브로모스티렌 등의 할로겐 치환 스티렌류 ; p-하이드록시스티렌,

-메틸-p-하이드록시스티렌, 2-메틸-4-하이드록시스티렌, 3,4-디하이드록시스티렌 등의 하이드록시스티렌류 ; 비닐벤질알코올류 ; p-메톡시스티렌, p-t-부톡시스티렌, m-t-부톡시스티렌 등의 알콕시 치환 스티렌류 ; 3-비닐벤조산, 4-비닐벤조산 등의 비닐벤조산류 ; 메틸-4-비닐벤조에이트, 에틸-4-비닐벤조에이트 등의 비닐벤조산에스테르류 ; 4-비닐벤질아세테이트 ; 4-아세톡시스티렌 ; 2-부틸아미드스티렌, 4-메틸아미드스티렌, p-술폰아미드스티렌 등의 아미드스티렌류 ; 3-아미노스티렌, 4-아미노스티렌, 2-이소프로페닐아닐린, 비닐벤질디메틸아민 등의 아미노스티렌류 ; 3-니트로스티렌, 4-니트로스티렌 등의 니트로스티렌류 ; 3-시아노스티렌, 4-시아노스티렌 등의 시아노스티렌류 ; 비닐페닐아세토니트릴 ; 페닐스티렌 등의 아릴스티렌류, 인덴류 등을 들 수 있는데, 본 발명은 이들 구체예에 한정되는 것은 아니다. 이들 단량체는, 2 종 이상을 공중합 성분으로서 사용해도 된다. 이들 중, 공업적으로 입수가 용이하고, 또한 저가인 점에서, 스티렌,

-메틸스티렌이 바람직하다.The said general formula (9) is a structural unit obtained from an aromatic vinylic monomer. As a specific example of the said aromatic vinylic monomer, Styrene;

Alkyl substituted styrenes such as -methyl styrene, β-methyl styrene and p-methyl styrene; Halogen-substituted styrenes such as 4-chlorostyrene and 4-bromostyrene; p-hydroxystyrene,

Hydroxy styrenes such as -methyl-p-hydroxy styrene, 2-methyl-4-hydroxy styrene and 3,4-dihydroxy styrene; Vinyl benzyl alcohol; alkoxy substituted styrenes such as p-methoxy styrene, pt-butoxy styrene and mt-butoxy styrene; Vinyl benzoic acids such as 3-vinyl benzoic acid and 4-vinyl benzoic acid; Vinyl benzoic acid esters such as methyl-4-vinyl benzoate and ethyl-4-vinyl benzoate; 4-vinyl benzyl acetate; 4-acetoxy styrene; Amide styrenes such as 2-butylamide styrene, 4-methylamide styrene and p-sulfonamide styrene; Amino styrenes such as 3-amino styrene, 4-amino styrene, 2-isopropenyl aniline and vinyl benzyl dimethylamine; Nitrostyrenes such as 3-nitrostyrene and 4-nitrostyrene; Cyanostyrenes such as 3-cyanostyrene and 4-cyanostyrene; Vinyl phenyl acetonitrile; Aryl styrene, indenes, etc., such as phenyl styrene, are mentioned, However, This invention is not limited to these specific examples. These monomers may use 2 or more types as a copolymerization component. Among these, styrene, since it is easy to obtain industrially and is inexpensive,

-Methyl styrene is preferred.

General formula (10) is a structural unit obtained from an acrylate ester monomer. Examples of the acrylate monomers include methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), butyl acrylate (n-, i-, s-, t-), pentyl acrylate (n-, i-, s-), hexyl acrylate (n-, i-), heptyl acrylate (n-, i-), octyl acrylate (n-, i-), nonyl acrylate (n-, i-), myristyl acrylate (n-, i-), acrylic acid (2-ethylhexyl), acrylic acid (ε-caprolactone), acrylic acid (2-hydroxyethyl), acrylic acid (2-hydroxypropyl), acrylic acid (3-hydroxypropyl) , Acrylic acid (4-hydroxybutyl), acrylic acid (2-hydroxybutyl), acrylic acid (2-methoxyethyl), acrylic acid (2-ethoxyethyl) phenyl acrylate, phenyl methacrylate, acrylic acid (2 or 4- Chlorophenyl), methacrylic acid (2 or 4-chlorophenyl), acrylic acid (2 or 3 or 4-ethoxycarbonylphenyl), methacrylic acid (2 or 3 or 4-ethoxycarbonylphenyl), acrylic acid ( o or m or p-tolyl), methacryl Acids (o or m or p-tolyl), benzyl acrylate, benzyl methacrylate, phenethyl acrylate, phenethyl methacrylate, acrylic acid (2-naphthyl), cyclohexyl acrylate, cyclohexyl methacrylate, acrylic acid (4- Methylcyclohexyl), methacrylic acid (4-methylcyclohexyl), acrylic acid (4-ethylcyclohexyl), methacrylic acid (4-ethylcyclohexyl) or the like, or those in which the acrylic acid ester is replaced with methacrylic acid ester The present invention is not limited to these embodiments. These monomers may use 2 or more types as a copolymerization component. Among these, since it is industrially easy and inexpensive, methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), butyl acrylate (n-, i-, s-, t-), acrylic acid It is preferable to change pentyl (n-, i-, s-), hexyl acrylate (n-, i-), or the said acrylic acid ester into methacrylic acid ester.

As an additive, the copolymer which contains both the structure represented by General formula (9) and the structure represented by General formula (10) may be sufficient. Moreover, it is preferable that it is excellent in copolymerizability with the said monomer as another structure which comprises a copolymerization composition. Examples include maleic anhydride, citraconic anhydride, cis-1-cyclohexene-1,2-anhydrous dicarboxylic acid, 3-methyl-cis-1-cyclohexene-1,2-anhydrous dicarboxylic acid, 4 Nitrile-group-containing radically polymerizable monomers such as acid anhydrides such as -methyl-cis-1-cyclohexene-1,2-anhydrous dicarboxylic acid, acrylonitrile and methacrylonitrile; Amide bond-containing radically polymerizable monomers such as acrylamide, methacrylamide and trifluoromethanesulfonylaminoethyl (meth) acrylate; Fatty acid vinyls such as vinyl acetate; Chlorine-containing radically polymerizable monomers such as vinyl chloride and vinylidene chloride; Although conjugated diolefins, such as 1, 3- butadiene, isoprene, and 1, 4- dimethyl butadiene, are mentioned, It is not limited to these.

When using such a copolymer, it is preferable to contain at least 30 mol% of structures represented by General formula (9) in a copolymer composition. Moreover, it is preferable to contain at least 20 mol% or more of the structure represented by General formula (10). Moreover, it is preferable that the ratio of another copolymerization component is 50 mol% or less.

It is preferable that the weight average molecular weights of the compound which has a structure represented by General formula (9) or (10) are 500 or more and 300000 or less, It is excellent in compatibility with a binder, transparency of the film after film forming, and favorable optical characteristic. In order to obtain the film shown, it is more preferable that it is 500 or more and 15000 or less, and it is especially preferable that it is 500 or more and 5000 or less. The weight average molecular weight of the said compound is the value measured by GPC (developing solvent: tetrahydrofuran, the polystyrene conversion method).

(Synthesis of additives)

The additive used preferably by this invention mentioned above can also be synthesize | combined.

For example, the additive of General formula (1) can be obtained by condensation reaction of a sulfonyl chloride derivative and an amine derivative. Moreover, the compound of General formula (2) can be obtained by oxidation reaction of sulfide or Friedel-Crafts reaction of aromatic compound and sulfonic acid chloride.

(Addition amount of additive)

The addition amount of the additive represented by General Formula (1)-(5) used preferably by this invention mentioned above is 5 mass% or more, for example with respect to resin which comprises a film. It is preferable that it is 5-40 mass%, and it is more preferable that it is 20-30 mass%. When the added amount is less than 5% by mass, the value of moisture content x oxygen permeability is (1) low: the polarizing plate bonding ability is poor, and is easy to peel off after the polarizing plate processing, and (2) the high case: the problem of poor durability of the wet heat durability test It may occur.

Moreover, 1 type may be used for the said additive, and 2 or more types may be used for it. When 2 or more types are used, it is preferable that it is 5-40 mass%, and, as for the addition amount of two or more types of additives, the total amount of two types of addition adds 20-30 mass% more.

It is preferable that the compound which has a structure represented by General formula (9) or (10) used preferably by this invention mentioned above is 5-40 mass% of resin which comprises a film, and it is excellent in transparency after film forming, It is more preferable that it is 20-30 mass% in order to obtain the film which shows favorable expressivity of an optical characteristic.

Moreover, the compound which has a structure represented by these General formula (9) or (10) may be used independently, and may mix and use 2 or more types of compounds by arbitrary ratios.

It is preferable that the total content of the compound which has a structure represented by two or more types of general formula (9) or (10) is 5-40 mass% of resin which comprises a film, It is excellent in transparency after film forming, and favorable optical characteristic In order to obtain the film which shows the property, it is more preferable that it is 20-30 mass%.

(Addition method of additive)

Moreover, these additives may be used independently and may mix and use 2 or more types of additives in arbitrary ratios.

In addition, the timing of adding these additives may be any time in the solution (dope) manufacturing process of resin which comprises a film, and may be performed at the end of a dope preparation process.

5-40 mass% is preferable with respect to the polymer contained in a film, 8-35 mass% is more preferable, 10-30 mass% is further more preferable.

(Particulates)

By adding microparticles | fine-particles to the film of this invention, the film forming stability and processability of a film can be improved further, and the optical nonuniformity of the film derived from a winding imbalance etc. can be reduced. As microparticles | fine-particles which can be used by this invention, the microparticles | fine-particles of an organic or an inorganic compound can be used.

As the inorganic compound, a compound containing silicon, silicon dioxide, titanium oxide, zinc oxide, aluminum oxide, barium oxide, zirconium oxide, strontium oxide, antimony oxide, tin oxide, tin oxide / antimony, calcium carbonate, talc, clay, Calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, and the like are preferred, and more preferably an inorganic compound or a metal oxide containing silicon. That is, in the present invention, a metal oxide or an inorganic silicon compound is preferably used as the fine particles. In the present invention, since turbidity of the film can be reduced, silicon dioxide is particularly preferably used. As microparticles | fine-particles of silicon dioxide, the commercial item which has brand names, such as aerosil R972, R974, R812, 200, 300, R202, OX50, TT600 (above Nippon Aerosil Co., Ltd. product) can be used, for example. have. As microparticles | fine-particles of a zirconium oxide, what is marketed under brand names, such as aerosil R976 and R811 (above Nippon Aerosil Co., Ltd. product), can be used, for example.

Examples of the organic compound include polytetrafluoroethylene, cellulose acetate, polystyrene, polymethyl methacrylate, polypropyl methacrylate, polymethyl acrylate, polyethylene carbonate, starch, and the like. Alternatively, a spherical polymer compound synthesized by a suspension polymerization method, a spray dry method or a dispersion method can be used.

As a primary average particle diameter of microparticles | fine-particles, it is 0.001 micrometer-20 micrometers, More preferably, it is 0.001 micrometer-10 micrometers, More preferably, it is 0.002 micrometer-1 micrometer from a viewpoint of suppressing haze low. Preferably it is 0.005 micrometer-0.5 micrometer. The measurement of the primary average particle diameter of microparticles | fine-particles can obtain a particle | grain with an average particle diameter with a transmission electron microscope. The purchased fine particles are often aggregated, and it is preferable to disperse them by a known method before use. It is preferable to make a secondary particle diameter into 0.2 micrometer-1.5 micrometers by dispersion, and 0.3 micrometer-1 micrometer are more preferable. 0.01 mass part-0.3 mass parts are preferable with respect to 100 mass parts of resin which comprises a film, as for the addition amount of microparticles | fine-particles, 0.05 mass part-0.2 mass part are more preferable, 0.08 mass part-0.12 mass part are the most preferable.

In the case of dispersing the particles, since the haze increases and the transparency is reduced, the average particle size is preferably 0.001 µm to 100 µm, more preferably 0.01 µm to 10 µm, still more preferably 0.01 µm to 5 µm. to be.

Moreover, it is preferable that content is 0.0001 mass%-10 mass% in the whole film, regardless of the case where it disperse | distributes to particulate form, such as spherical form and amorphous form, or disperse | distributes in molecular form, for example, Preferably they are 0.001 mass%-5 mass%, More preferably, they are 0.01 mass%-3 mass%.

The range of the preferable light transmittance of the film of this invention is 88.0% or more, 89.0% or more is more preferable, 90.0% or more is especially preferable. The said transmittance | permeability measured the sample 13 mm x 40 mm at 25 degreeC and 60% RH by the spectrophotometer (U-3210, Hitachi, Ltd.) at the measurement wavelength of 550 nm.

Although the injection | pouring method to the film of the said compound is not specifically limited, The coating liquid which contains the said compound in the film after casting | flow_spreading the resin which comprises a film and the solution containing the said compound, and the film | membrane which make up the film are cast | flow-spreaded. The method of coating and the method of carrying out middle layer casting | fusing etc. are mentioned. In this invention, it is preferable to manufacture a film by either of the following two manufacturing methods.

1. The manufacturing method of the film containing the resin which comprises a film, and the process of melt | dissolving or disperse | distributing at least 1 sort (s) of compound in a solvent, the process of casting, the process of drying, and the process of winding up.

2. A method for producing a film comprising the step of dissolving a resin constituting the film in a solvent, a step of casting, a step of drying, and a step of winding up, wherein at least one surface of the film after casting is formed. The manufacturing method of the film containing the process of coating the coating liquid containing a compound of a seed.

By manufacturing by either of the said two methods, the film suitable as an optical film excellent in planarity, uniformity, etc. can be manufactured, and it is more preferable.

In the method of 1 above, the solution containing the resin and the compound constituting the film is cast to form a film. In the case of this method, when preparing the solution of resin which comprises a film, the said compound is melt | dissolved or disperse | distributed, You may add the solution or dispersion liquid of the said compound just before making the solution of resin which comprises a film soft. In preparation of a dispersion liquid, well-known methods, such as a conventional stirrer, the soft high speed stirrer for homogenizers, the ball mill, the paint shaker, the dispersion | distribution using media like a dyno mill, an ultrasonic disperser, etc. can be used. When disperse | distributing the said compound to the solution of resin which comprises a film, you may add a small amount of surfactant or a polymer normally used as a dispersing adjuvant.

In the method of 2 above, the "coating solution" should just have the said compound as a main component. The coating liquid may be simply coated on the surface of the layer (that is, the film after casting) which contains the resin constituting the film as a main component, as a coating liquid, which is a solution or dispersion obtained by dissolving or dispersing the compound in a suitable solvent. Moreover, the coating liquid may contain the binder and may form the layer containing the said compound by coating this coating liquid.

The coating solution can be coated on one side or both sides of a layer composed mainly of resin constituting the film.

It does not specifically limit as a binder for layer formation of the said compound, A lipophilic binder may be sufficient and a hydrophilic binder may be sufficient. As the lipophilic binder, known thermoplastic resins, thermosetting resins, radiation curable resins, reactive resins, and mixtures thereof can be used.

80 degreeC-400 degreeC is preferable, and, as for Tg of the said resin, 120 degreeC-350 degreeC is more preferable. 10,000-1 million are preferable and, as for the mass mean molecular weight of the said resin, 10,000-500,000 are more preferable. When disperse | distributing the said compound in a coating liquid, the same dispersing method as the said 1 method can be used, You may add a small amount of surfactant or a polymer normally used as a dispersal auxiliary agent.

Examples of the thermoplastic resin include vinyl chloride and vinyl acetate copolymers, vinyl chloride, copolymers of vinyl acetate and vinyl alcohol, maleic acid and / or acrylic acid, vinyl chloride and vinylidene chloride copolymers, and vinyl acrylonitrile copolymers. Vinyl copolymers such as copolymers, ethylene-vinyl acetate copolymers, cellulose derivatives such as nitrocellulose, cellulose acetate propionate, cellulose acetate butyrate resin, cyclic polyolefin resins, acrylic resins, polyvinyl acetal resins, and polyvinyl buty Ral resin, polyester polyurethane resin, polyether polyurethane, polycarbonate polyurethane resin, polyester resin, polyether resin, polyamide resin, amino resin, styrene-butadiene resin, butadiene acrylonitrile resin and other rubber-based resins, silicone-based Resins, fluorine resins, and the like. The.

The layer thickness of the layer containing the compound is preferably from 0.0001 to 10 µm, more preferably from 0.001 to 5 µm, still more preferably from 0.01 to 1 µm.

More detail of the manufacturing method of a film is mentioned later.

(Other additives)

To the film of the present invention, various additives (for example, a deterioration inhibitor, a sunscreen, a peeling accelerator, a plasticizer, an infrared absorber, etc.) according to the use can be added to each film in the manufacturing process, and they may be solid, It may be an oily substance. That is, it is not specifically limited in the melting point or boiling point. For example, it is mixing of 20 degrees C or less and 20 degrees C or more ultraviolet absorbing material, similarly mixing deterioration inhibitor, etc. Moreover, as an infrared absorbing dye, it is described, for example in Unexamined-Japanese-Patent No. 2001-194522. Moreover, although the addition time may be added any time in the solution (dope) manufacturing process of resin which comprises a film, you may add and add the process of adding an additive to the last preparation process of a dope preparation process. In addition, the addition amount of each raw material is not specifically limited as long as a function is expressed. Moreover, when a film is formed in multiple layers, the kind and addition amount of the additive of each layer may differ.

(Deterioration inhibitor)

Known deterioration (oxidation) inhibitors in the solution of the resin constituting the film, for example 2,6-di-t-butyl, 4-methylphenol, 4,4'-thiobis- (6-t-butyl-3 -Methylphenol), 1,1'-bis (4-hydroxyphenyl) cyclohexane, 2,2'-methylenebis (4-ethyl-6-t-butylphenol), 2,5-di-t-butyl Phenol-type or hydroquinone type antioxidants, such as hydroquinone and pentaerythryl- tetrakis [3- (3, 5- di-t- butyl- 4-hydroxyphenyl) propionate], can be added. Further, tris (4-methoxy-3,5-diphenyl) phosphite, tris (nonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, bis (2,6-di It is preferable to add phosphorus antioxidant, such as -t- butyl- 4-methylphenyl) pentaerythritol diphosphite and bis (2, 4- di-t-butylphenyl) pentaerythritol diphosphite. Antioxidant adds 0.05-5.0 mass parts with respect to 100 mass parts of resin which comprises a film.

(UV absorber)

A ultraviolet absorber can be added to the solution of resin which comprises a film from a viewpoint of prevention of deterioration, such as a polarizing plate or a liquid crystal. As a ultraviolet absorber, the thing which is excellent in the absorption ability of the ultraviolet-ray of wavelength 370nm or less, and has the low absorption of the visible light of wavelength 400nm or more from a viewpoint of favorable liquid crystal display property is used preferably. As a specific example of the ultraviolet absorber used preferably for this invention, a hindered phenol type compound, an oxybenzo phenone type compound, a benzotriazole type compound, a salicylic acid ester type compound, a benzophenone type compound, a cyanoacrylate type, A compound, a nickel complex salt compound, etc. are mentioned. Examples of the hindered phenol compound include 2,6-di-tert-butyl-p-cresol and pentaerythryl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate], N, N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamid), 1,3,5-trimethyl-2,4,6-tris ( 3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris (3,5-di-tert-butyl-4-hydroxybenzyl) -isocyanurate, etc. are mentioned. Examples of the benzotriazole-based compound include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole and 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6 -(2H-benzotriazol-2-yl) phenol), (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino)- 1,3,5-triazine, triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], N, N'-hexamethylenebis (3, 5-di-tert-butyl-4-hydroxy-hydrocinnamid), 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) Benzene, 2 (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorbenzotriazole, (2 (2'-hydroxy-3', 5'-di-tert- Amylphenyl) -5-chlorbenzotriazole, 2,6-di-tert-butyl-p-cresol, pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxy Phenyl) propionate, etc. The addition amount of these ultraviolet inhibitors is 1 by mass ratio in the whole film. ppm-1.0% are preferable, and 10-1000 ppm are more preferable.

(Plasticizer)

A plasticizer can be added to the film of this invention. Specifically, phthalic acid ester, trimellitic acid ester, aliphatic dibasic acid ester, positive phosphate ester type, acetate ester type, polyester / epoxy ester type, ricinolic acid ester type, polyolefin type, polyethylene And glycol compounds.

As a plasticizer which can be used, it is preferable to select from the compound which is normal temperature, normal pressure, and a liquid phase, and whose boiling point is 200 degreeC or more. As a specific compound name, the following can be illustrated.

As an aliphatic dibasic ester type, dioctyl adipate (230 degreeC / 760 mmHg), dibutyl adipate (145 degreeC / 4 mmHg), di-2-ethylhexyl adipate (335 degreeC / 760 mmHg), for example. , Dibutyl diglycol adipate (230-240 ° C./2 mmHg), di-2-ethylhexyl azelate (220-245 ° C./4 mmHg), di-2-ethylhexyl sebacate (377 ° C./760 mmHg) ) Etc ; As phthalic acid ester type, diethyl phthalate (298 degreeC / 760 mmHg), diheptyl phthalate (235-245 degreeC / 10 mmHg), di-n-octyl phthalate (210 degreeC / 760 mmHg), diisodecyl phthalate, for example. (420 ° C./760 mmHg) and the like; As a polyolefin type, paraffin wax (average molecular weight 330-600, melting | fusing point 45-80 degreeC), such as normal paraffin, isoparaffin, cycloparaffin, liquid paraffins (JIS standard K2231ISO VG8, JIS standard K2231ISO VG15, JIS standard K2231ISO VG32, JIS standard K2231ISO VG68, JIS standard K2231ISO VG100, etc.), paraffin pellets (melting point 56-58 ° C, 58-60 ° C, 60-62 ° C, etc.), paraffin chloride, low molecular weight polyethylene, low molecular weight polypropylene, low molecular weight polyisopart Ten, hydrogenated polybutadiene, hydrogenated polyisoprene, squalane and the like.

As addition amount of a plasticizer, it is 0.5-40.0 mass parts with respect to 100 mass parts of resin which comprises a film, Preferably it is 1.0 mass part-30.0 mass parts, More preferably, it is 3.0-20.0 mass parts. If the amount of the plasticizer added is less than this, the plasticizing effect is insufficient, and workability is not improved. Moreover, when it is longer than this, when a long time passes, a plasticizer may separate and elute, and an optical nonuniformity, contamination with other components, etc. generate | occur | produce, and it is unpreferable.

Hereinafter, the manufacturing method of the film of this invention is demonstrated in detail. As a solution casting method, a film can be manufactured by either of the following two manufacturing methods.

1. Resin which comprises a film, If desired, The manufacturing method of the film containing the process of melt | dissolving or disperse | distributing at least 1 type of compound in a solvent, the process of casting | flow_spread, the process of drying, and the process of winding up.

2. A method for producing a film comprising a step of dissolving a resin constituting the film in a solvent, a step of casting, a step of drying, and a step of winding up, as desired, at least one side of the film after casting. The manufacturing method of the film containing the process of coating the coating liquid containing at least 1 sort (s) of compound on it.

Moreover, it extends | stretches after the said flexible process.

In addition, the two manufacturing methods of said 1 and said 2 differ in the injection method of a compound with respect to a film. In the method of 1 above, the compound is dissolved or dispersed in the same layer with respect to the layer containing the resin constituting the film as the main component, whereas in the method of 2, the compound is contained with respect to the layer containing the resin constituting the film as the main component. It differs in the point which coats the coating liquid containing these.

Hereinafter, although each process is explained in full detail from (process to melt | dissolve, dope preparation) to (process to wind up after drying), the said 1 manufacturing method is melt | dissolution or dispersion in (process to dissolve, dope preparation), It is the same as that of the said 2 manufacturing method except adding.

(Process to dissolve, dope preparation)

First, each material component is dissolved in the solvent mentioned later, and the solution (dope) of resin which comprises a film is prepared. About the preparation of dope, the method by room temperature stirring dissolution, the resin etc. which make up a film by stirring at room temperature, and swell are cooled, and it cools from -20 to -100 degreeC, and heats again to 20-100 degreeC, and melt | dissolves, sealing There exists a high temperature melt | dissolution method of melt | dissolving to the temperature more than the boiling point of a main solvent in a container, and also the method of melt | dissolving to high temperature and high pressure to the critical point of a solvent, etc. are mentioned. Room temperature dissolution is preferable for resins having good solubility, but resins having poor solubility are heated and dissolved in an airtight container. Solubility is not too bad, it is efficient to choose a temperature as low as possible.

In the present invention, the viscosity of the dope is preferably in the range of 1 to 500 Pa · s at 25 ° C. More preferably, it is the range of 5-200 Pa.s. Viscosity can be measured using a steel cone (both manufactured by TA Instruments) having a diameter of 4 cm / 2 ° on a rheometer (CLS 500). The sample solution is insulated until the liquid temperature becomes constant at the measurement start temperature in advance, and then starts the measurement.

The solvent used when preparing dope is described. In this invention, the solvent which can be used is not specifically limited as long as the objective can be achieved in the range which resin etc. which comprise a film can melt | dissolve, cast | flow, and film forming. The solvent used in the present invention is preferably, for example, a chlorine-based solvent such as dichloromethane or chloroform, a chain hydrocarbon having 3 to 12 carbon atoms, a cyclic hydrocarbon, an aromatic hydrocarbon, an ester, a ketone, or an ether. . The ester, ketone, and ether may have a cyclic structure. Examples of the linear hydrocarbons having 3 to 12 carbon atoms include hexane, octane, isooctane and decane. Cyclopentane, cyclohexane, and its derivative (s) are mentioned as cyclic hydrocarbons of 3-12 carbon atoms. Examples of the aromatic hydrocarbon having 3 to 12 carbon atoms include benzene, toluene, xylene and the like. Examples of esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, and pentyl acetate. Examples of ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, and methylcyclohexanone. Examples of ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phentol Can be mentioned. 2-ethoxyethyl acetate, 2-methoxyethanol, and 2-butoxyethanol are mentioned as an example of the organic solvent which has two or more types of functional groups. Preferable boiling points of the organic solvent are 35 degreeC or more and 150 degrees C or less. The solvent used in the present invention can be used by mixing two or more kinds of solvents in order to adjust solution properties such as drying property and viscosity, and as long as the resin constituting the film with the mixed solvent is dissolved. A solvent may also be added.

A preferable poor solvent can be suitably selected according to the polymer type to be used. When using a chlorine organic solvent as a good solvent, alcohol can be used preferably. As alcohol, Preferably, it may be linear, may have a branch, or may be cyclic, and it is especially preferable that it is a saturated aliphatic hydrocarbon. The hydroxyl group of the alcohol may be any of the first to third classes. Examples of alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, 2-methyl-2-butanol and cyclohexanol. Moreover, a fluorine-type alcohol is also used as alcohol. For example, 2-fluoroethanol, 2,2,2-trifluoroethanol, 2,2,3,3- tetrafluoro-1-propanol, etc. are mentioned. Especially in a poor solvent, monohydric alcohol has the effect of reducing peeling resistance, and can be used preferably. Although particularly preferable alcohols change according to the positive solvent to select, in consideration of drying load, the alcohol whose boiling point is 120 degrees C or less is preferable, the monohydric alcohol of 1-6 carbon atoms is more preferable, and C1-C1 is preferable. The alcohols of 4 can be used especially preferably. A particularly preferable mixed solvent is a combination in which dichloromethane is the main solvent and at least one alcohol selected from methanol, ethanol, propanol, isopropanol or butanol is a poor solvent.

The cyclic polyolefin solution is characterized in that a high concentration of dope is obtained by appropriately selecting a solvent to be used, and a cyclic polyolefin solution having a high concentration and excellent stability is obtained regardless of the means of concentration. Moreover, in order to make it easy to melt | dissolve, you may melt | dissolve at low density | concentration, and you may concentrate using a concentration means. Although it does not specifically limit as a concentration method, For example, while a low concentration solution is guide | induced between the cylinder and the rotational trajectory of the rotating blade outer periphery which rotates in the circumferential direction inside it, A method of obtaining a high concentration solution while evaporating the solvent by providing a temperature difference between the two (eg, JP-A-4-259511, etc.), by blowing a heated low concentration solution from the nozzle into the container, and then pouring the solution from the nozzle. Flash evaporation of the solvent until it reaches the inner wall of the vessel, withdrawal of the solvent vapor from the vessel, and removal of the high concentration solution from the bottom of the vessel (e.g. U.S. Pat. No. 2,541,012, U.S. Pat.No. 2,858,229, U.S. Patent 4,414,341, US Pat. No. 4,504,355, etc.) and the like.

It is preferable to filter out foreign substances, such as undissolved matter, dust, and an impurity, using a suitable filter medium, such as a wire mesh or a nel, before a solution is cast. It is preferable to use the filter of 0.1 micrometer-100 micrometers of absolute filtration accuracy, and, further, to use the filter of 0.5 micrometer-25 micrometers of absolute filtration precision for the filtration of the resin solution which comprises a film. 0.1 micrometer-10 mm are preferable, and also as for the thickness of a filter, 0.2 mm-2 mm are preferable. In that case, the filtration pressure is preferably 1.6 MPa or less, more preferably 1.3 MPa or less, more preferably 1.0 MPa or less, particularly preferably 0.6 MPa or less. As a filter medium, conventionally well-known materials, such as fluororesins, such as glass fiber, a cellulose fiber, a filter paper, and a tetrafluoroethylene resin, can be used preferably, Ceramics, a metal, etc. are also used preferably.

What is necessary is just to be the range which can be flexible at the time of film forming, and the viscosity just before film forming of dope, It is preferable to be prepared in the range of 5 Pa.s-1000 Pa.s normally, 15 Pa.s-500 Pa.s are more preferable, 30 Pa.s-200 Pa.s are more preferable. The temperature at this time is not particularly limited as long as it is the temperature at the time of casting, but it is preferably -5 to 70 ° C, more preferably -5 to 35 ° C.

As the method and equipment for producing the film of the present invention, the same solution casting film forming method and solution casting film forming apparatus as those used for conventional film production made of cellulose triacetate are used. The dope prepared from the dissolver (kiln) is once stored in a storage kiln, and the air bubbles contained in the dope are defoamed to make final preparation. The dope is sent from the dope outlet to a pressurized die through a pressurized metering gear pump capable of metering at high accuracy according to the rotational speed, for example, and the dope is running endlessly from the detention (slit) of the pressurized die. At a peel point where the metal support is uniformly cast on the metal support and the metal support is almost round, the less dried dope film (also called a web) is peeled off from the metal support. Both ends of the web obtained are clipped, conveyed by a tenter, and dried, conveyed by the roll group of a drying apparatus, and drying is complete | finished and wound up to a predetermined length by a winder. The combination of a tenter and a drying apparatus of a roll group changes with the objective. In the solution casting film forming method used for the functional protective film for electronic displays, in addition to the solution casting film forming apparatus, the coating device is used for surface processing on films such as a lower layer, an antistatic layer, an antihalation layer, a protective layer, and the like. Is often added. Although each manufacturing process is briefly described below, it is not limited to these.

The dope is preferably casted on an endless metal support, for example on a metal drum or metal support (band or belt), and the solvent is evaporated to form a film. It is preferable that the dope before casting | flow_spread adjusts concentration so that the amount of resin which comprises a film may be 10-35 mass%. It is preferable to finish the surface of a drum or a band in a mirror surface state. It is preferable to make dope cast on the drum or band whose surface temperature is 30 degrees C or less, and it is especially preferable that it is a metal support temperature of -50-20 degreeC.

In addition, Japanese Unexamined Patent Publication No. 2000-301555, Japanese Unexamined Patent Publication No. 2000-301558, Japanese Unexamined Patent Publication No. Hei 7-032391, Japanese Unexamined Patent Publication No. 3-193316, Japanese Unexamined Patent Application Publication No. 5-086212, Japan Each of Unexamined-Japanese-Patent No. 62-037113, Unexamined-Japanese-Patent No. 2-276607, Unexamined-Japanese-Patent No. 55-014201, Unexamined-Japanese-Patent No. 2-111511, and Unexamined-Japanese-Patent No. 2-208650. The cellulose acylate film forming technique described in the publication can be applied in the present invention.

(Flexible, mid layer flexible)

The dope may be cast as a monolayer liquid on a smooth band or drum as a metal support, or a plurality of two or more layers of dope may be cast.

In the case where a plurality of dope is cast, a film may be produced while the dope is cast and laminated from a plurality of oil studies formed at intervals in the advancing direction of the metal support, for example, JP-A-61-158414, Japan The method described in Unexamined-Japanese-Patent No. 1-122419, Unexamined-Japanese-Patent No. 11-198285, etc. can be adapted.

Moreover, it can also film-form by making dope soft from two oil studies, For example, Unexamined-Japanese-Patent No. 60-27562, Unexamined-Japanese-Patent No. 61-94724, Unexamined-Japanese-Patent No. 61-947245, Japan It can carry out by the method as described in each Unexamined-Japanese-Patent No. 61-104813, Unexamined-Japanese-Patent No. 61-158413, and Unexamined-Japanese-Patent No. 6-134933. Moreover, the film casting method of wrapping the flow of the high viscosity dope of Unexamined-Japanese-Patent No. 56-162617 with the low viscosity dope, and simultaneously extruding the high viscosity and the low viscosity dope may be sufficient. Moreover, it is also a preferable aspect that the outer solution of Unexamined-Japanese-Patent No. 61-94724 and Unexamined-Japanese-Patent No. 61-94725 contains more alcohol component which is a poor solvent than an inner solution. Alternatively, the film may be prepared by peeling the film formed on the metal support by the first oil study and performing the second casting on the side in contact with the metal support surface using two oil studies. For example, it is the method of Unexamined-Japanese-Patent No. 44-20235. The dope to be cast may be the same solution, may be a different dope, and is not specifically limited. In order to give a some resin layer a function, what is necessary is just to extrude the dope according to the function from each oil research. Moreover, dope can also carry out simultaneously softening another functional layer (for example, an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, a mat agent layer, a UV absorption layer, a polarizing layer, etc.).

In the monolayer liquid, in order to achieve the required film thickness, it is necessary to extrude a high concentration and high viscosity dope, and in this case, the stability of the dope is poor, and a solid material is generated, which is a problem due to protrusion failure or poor planarity. In order to solve this problem, by casting a plurality of dope from oil research, a solution having a high viscosity can be extruded on a metal support at the same time, the planarity is also increased, and an excellent planar film can be produced. The reduction of a dry load can be achieved by this, and the production speed of a film can be raised.

In the case of the covalent lead, the thickness of the inside and the outside is not particularly limited, but preferably the outside is 1 to 50% of the total film thickness, and more preferably 2 to 30% of the thickness. . Here, in the case of three or more layers of covalent lead, the total film thickness of the layer which contact | connected the metal support body, and the layer which contact | connects the air side is defined as outer thickness. In the case of a covalent lead, the dope of which the above-mentioned additive concentration differs may be covalently leaded, and the film of a laminated structure can also be manufactured. For example, the film of the structure similar to a skin layer / core layer / skin layer can be manufactured. A deterioration inhibitor and a ultraviolet absorber can be put in a core layer more than a skin layer, and you may put only a core layer. Moreover, the kind of a degradation inhibitor and an ultraviolet absorber can also be changed in a core layer and a skin layer, For example, a low volatility inhibitor and / or an ultraviolet absorber are included in a skin layer, and a plasticizer excellent in plasticity or an ultraviolet-ray is included in a core layer. Ultraviolet absorbers excellent in water absorption can also be added. Moreover, it is also a preferable aspect to contain a peeling accelerator only in the skin layer of the metal support side. Moreover, in order to cool a metal support body and gelatinize a solution by the cooling drum method, it is also preferable to add more alcohol which is a poor solvent to a skin layer more than a core layer. Tg of a skin layer and a core layer may differ, and it is preferable that Tg of a core layer is lower than Tg of a skin layer. Moreover, although the viscosity of the dope at the time of casting | flow_spread may differ from a skin layer and a core layer, it is preferable that the viscosity of a skin layer is smaller than the viscosity of a core layer, but the viscosity of a core layer may be smaller than the viscosity of a skin layer.

(softness)

As a method of casting the dope, a method of uniformly extruding the prepared dope from the press die on the metal support, a method by the doctor blade for controlling the film thickness of the dope once cast on the metal support with the blade, or the reverse rotation Although there exist a method by the reverse roll coater adjusted with a roll, the method by a press die is preferable. There are a coat hanger type, a T-die type, etc. in pressurization die | dye, All can use it preferably. In addition to the method exemplified here, the conventionally known cellulose triacetate solution can be carried out by various methods for flexibly forming a film, and by setting the respective conditions in consideration of the difference in boiling point of the solvent to be used, The same effect is obtained. As an endless metal support used for producing the film of the present invention, a drum whose surface is mirror-finished by chrome plating or a stainless steel belt (also referred to as a band) mirror-finished by surface polishing is used. The press die used for the film production of this invention may be provided 1 group or 2 or more groups above the metal support body. Preferably it is 1 group or 2 groups. In the case where two or more units are provided, the amount of the dope to be cast may be divided into various dies at various ratios, or the dope may be fed to the dies at each ratio from a plurality of precision metering gear pumps. As for the temperature of the dope used for casting, -10-55 degreeC is preferable, More preferably, it is 25-50 degreeC. In that case, the whole process may be the same, or may differ in each part of a process. When different, what is necessary is just to desire temperature just before casting | flow_spread.

(dry)

Drying of the dope on the metal support which concerns on manufacture of a film is generally a method of shooting hot air from the surface side of a metal support (for example, a drum or a band), ie, the surface of the web on a metal support, a drum or Method of shooting hot air from the back of the band, liquid heat transfer method of controlling the surface temperature by heating the drum or the band by heat transfer by bringing the temperature-controlled liquid into contact with the back of the band or drum on the opposite side of the dope flexible surface. Etc., but the liquid electrothermal method is preferable. As long as the surface temperature of the metal support body before casting | flow_spread is below the boiling point of the solvent used for dope, you may be several degrees. However, in order to accelerate drying and to remove fluidity on the metal support, it is preferable to set the temperature at a temperature of 1 to 10 degrees lower than the boiling point of the solvent having the lowest boiling point. In addition, it does not apply when peeling without cooling and drying a casting dope.

(Peeling)

When peeling the less dried film from the metal support, if the peeling resistance (peel load) is large, the film is elongated irregularly in the film forming direction, causing optical anisotropy nonuniformity. In particular, when the peeling load is large, a portion that is extended in a short shape in the film forming direction and a portion that is not stretched alternately occur, causing distribution in the retardation. When it loads in a liquid crystal display device, a nonuniformity will be seen in linear form or strip | belt shape. In order not to produce such a problem, it is preferable to make the peeling load of a film into 0.25 N or less per 1 cm of film peeling widths. The peeling load is more preferably 0.2 N / cm or less, still more preferably 0.15 N or less, particularly preferably 0.10 N or less. When the peeling load is 0.2 N / cm or less, even in the liquid crystal display device in which nonuniformity tends to appear, the nonuniformity resulting from peeling is not confirmed at all, and it is especially preferable. As a method of reducing peeling load, there exist a method by which a peeling agent is added as mentioned above, and the method by selection of the solvent composition to be used.

The measurement of peeling load is performed as follows. The dope is dripped on the metal plate of the same material and surface roughness as the metal support body of a film forming apparatus, and it extends | stretches to equal thickness using a doctor blade, and it dries. An equal width of the sheath is inserted into the film with a cutter knife, the tip of the film is removed by hand, the clip is connected to the strain gauge, and the load gauge is measured while pulling the strain gauge in the inclined 45 degree direction. The volatile matter in the peeled film is also measured. The same measurement is performed several times by changing the drying time, and the peeling load at the same time as the residual volatile component at the time of peeling in the actual film forming step is determined. When the peeling rate is increased, the peeling load tends to be large, and it is preferable to measure at a peeling rate that is close to actuality.

The preferable residual volatile matter concentration at the time of peeling is 5 mass%-60 mass%. 10 mass%-50 mass% are more preferable, and 20 mass%-40 mass% are especially preferable. When peeling with high volatile matter, drying speed can be reduced and productivity improves and it is preferable. On the other hand, in high volatile matter, the strength and elasticity of the film are small, and the peeling force is insufficient, so that the film is cut or stretched. Moreover, the self-holding force after peeling is insufficient, and it becomes easy to generate a deformation | transformation, a wrinkle, and a Kunic. It also causes distribution in retardation.

(Stretching processing)

The stretched film of this invention is a film formed by said solution casting method, and it extends | stretches the film whose initial value of Rth (measured at (lambda = 590 nm)) is 30 nm or more at the temperature T which satisfy | fills following formula I). It is a film.

(Rth(T)/Rth(I))

0.9 Equation I) 0.2

(Rth (T) / Rth (I))

0.9

In the formula, Rth (T) is Rth (measured at λ = 590 nm) of the film after 3 minutes at temperature T in a state where at least two sides of the film are held, and Rth (I) is Initial value of Rth.

After measuring Tg of a film, temperature T can be determined by the method of evaluating each optical characteristic, etc. after actually processing a film at each temperature of Tg / Tg + 30 degreeC / Tg + 60 degreeC / Tg + 90 degreeC.

There is no restriction | limiting in particular in the method of extending a web. For example, a plurality of rolls have a circumferential speed difference, and in the meantime, a method of stretching in the longitudinal direction using the roll circumferential speed difference, both ends of the web are fixed with clips or pins, and the distance between the clips or pins in the advancing direction. The method of extending | stretching and extending | stretching to a longitudinal direction, the method of extending | stretching to a horizontal direction and extending | stretching to a transverse direction similarly, or the method of extending | stretching simultaneously to a longitudinal and horizontal direction, etc. are mentioned. Of course, you may use these methods in combination. In more detail, when a clip part is driven by a linear drive system, since extending | stretching can be performed smoothly and the risks, such as a fracture, can be reduced, the tenter method is more preferable.

Any general stretching machine may be used. For example, stretching may be performed by a single-sided five-stretch stretching method using film biaxial stretching apparatus 11A9 manufactured by Imoto Corporation. The manufacturing method of an unstretched film raises the temperature of a biaxial stretching apparatus to temperature T, and, in a stable state, opens a cover and grips a film as quickly as possible. Close the cover immediately and wait until the temperature reaches temperature T again. When temperature reaches, it is left to stand for 3 minutes. At the end of the standing time, the cover is opened to remove the sample and immediately cooled.

Next, about a stretched film, the temperature of a biaxial stretching apparatus is raised to temperature T, and in a stable state, a cover is opened and a film is gripped as quickly as possible. Close the cover immediately and wait until the temperature reaches temperature T again. When temperature reaches, it will stand for 1 minute in that state, and extending | stretching will start. Thereafter, the cover is opened to take out the sample and immediately cool.

(Rth(T)/Rth(I))

0.8 인 것이 더욱 바람직하다. In formula I), 0.5

(Rth (T) / Rth (I))

It is more preferable that it is 0.8.

When extending | stretching a film, it is preferable to carry out in the state in which the solvent remains still in the film just after peeling. The objective of extending | stretching is performed in order to obtain the film excellent in planarity without (1) wrinkles and a deformation | transformation, and (2) to enlarge in-plane retardation of a film. When extending | stretching for the purpose of (1), extending | stretching is performed at comparatively high temperature, and extending | stretching of low magnification from 1% to only 10% is also performed. Particular preference is given to stretching from 2% to 5%. When extending | stretching for both the objectives of (1) and (2), or the objective of (2) only, extending | stretching magnification is also extended | stretched to 5%-150% at comparatively low temperature.

Stretching of a film may be longitudinal or uniaxial uniaxial stretching, and simultaneous or sequential biaxial stretching may be sufficient as it. It is preferable that the birefringence of the VA liquid crystal cell and the optical compensation film for OCB liquid crystal cells becomes larger than the refractive index of a longitudinal direction. Therefore, it is preferable to extend | stretch a lot by the width direction.

In the film of this invention, the weight reduction rate for 60 minutes measured by TG-DTA in the temperature T which satisfy | fills said Formula I) is 5% or less. If the weight loss rate is greater than 5%, it is not preferable because of pyrolysis of molecules and volatilization contaminates the stretching process.

It is preferable that it is 4% or less, and, as for a weight reduction rate, it is more preferable that it is 3% or less.

A weight reduction rate is calculated | required by weight reduction rate (%) = [{(initial film weight)-(film weight after hold | maintaining at temperature T for 60 minutes)} / (initial film weight)] x100.

(After drying, winding up)

The film is dried again after stretching, and wound up with a residual volatile content of 2% or less.

Although the thickness of the completed (after drying) stretched film of this invention differs according to a use purpose, it is the range of 20 micrometers-500 micrometers normally, and the range of 30 micrometers-150 micrometers is preferable, and especially for a liquid crystal display device It is preferable that they are 40 micrometers-110 micrometers.

What is necessary is just to adjust the solid content concentration contained in dope, the slit gap of die | dye metal mold | die, the extrusion pressure from die | dye, the metal support speed, etc. so that the stretched film thickness may be made into desired thickness. 0.5 m-3 m are preferable, as for the width | variety of the stretched film obtained as mentioned above, More preferably, it is 0.6 m-2.5 m, More preferably, it is 0.8 m-2.2 m. If the width of the film is 0.5 m or more, the productivity is not reduced. If the width of the film is 3 m or less, the web handling property is deteriorated or the optical uniformity of the film is not reduced. It does not occur and is preferable. It is preferable to wind up the length in 100 m-10000 m per roll, More preferably, it is 500 m-7000 m, More preferably, it is 1000 m-6000 m. If the film length is 100 m or more, there is no reduction in productivity due to the increase in the frequency of roll replacement. If the film length is 10000 m or less, the web handling property is deteriorated, or the optical uniformity of the film is not reduced, and further, the film is twisted, It is preferable because undesirable phenomena such as streaks do not occur. When winding up, it is preferable to apply knurling to at least one end, the width is 3 mm-50 mm, More preferably, 5 mm-30 mm, The height is 0.5-500 micrometers, More preferably, 1-200 Μm. This may be one press or both presses. It is preferable that the deviation of the Re value of the full width is ± 5 nm, and more preferably ± 3 nm. In addition, the deviation of the Rth value is preferably ± 10 nm, more preferably ± 5 nm. Moreover, it is preferable that the deviation of Re value and Rth value of the longitudinal direction also exists in the range of the deviation of the width direction. In order to maintain transparency, the haze is preferably 0.01 to 2%.

(Optical Properties of Stretched Film)

Re

100 ㎚, 50 ㎚

Rth

300 ㎚ 를 만족하는 것이 바람직하다. 또, 50 ㎚

Re

70 ㎚, 90 ㎚

Rth

120 ㎚ 를 만족하는 것이 보다 바람직하다. 여기서, Re 는 λ = 590 ㎚ 에서 측정한 면내의 리타데이션 값이고, Rth 는 λ = 590 ㎚ 에서 측정한 두께 방향의 리타데이션 값이다. Although the preferable optical characteristic of the stretched film of this invention changes with the use of a film, in this invention, the optical characteristic after extending | stretching is 25 nm.

Re

100 nm, 50 nm

Rth

It is preferable to satisfy 300 nm. 50 nm

Re

70 nm, 90 nm

Rth

It is more preferable to satisfy 120 nm. Here, Re is an in-plane retardation value measured at λ = 590 nm, and Rth is a retardation value in the thickness direction measured at λ = 590 nm.

Moreover, it is preferable from the surface of the stretched film of this invention to satisfy the following conditions from the use of the optical film for liquid crystal display devices, especially for the retardation film for VA panels.

Rth/Re＋0.5

5 를 만족하는 것이 바람직하다 (Rth 는 λ = 590 ㎚ 에서 측정한 두께 방향의 리타데이션 값이고, Re 는 λ = 590 ㎚ 에서 측정한 면내의 리타데이션 값이다). 이 범위를 만족함으로써, VA 용의 액정 표시 장치를 광학 보상한다는 점에서 바람직하다. The stretched film of this invention is 1.75

Rth / Re + 0.5

It is preferable to satisfy 5 (Rth is a retardation value in the thickness direction measured at λ = 590 nm, and Re is an in-plane retardation value measured at λ = 590 nm). By satisfy | filling this range, it is preferable at the point of optically compensating for the liquid crystal display device for VA.

Moreover, as for the stretched film of this invention, it is preferable that haze is 3% or less. The haze measures a 40 mm x 80 mm film sample at 25 degreeC and 60% RH by haze meter "HGM-2DP" (made by Suga Test Machine Co., Ltd.) according to JIS K-6714.

The stretched film of this invention can implement | achieve a desired optical characteristic by suitably adjusting process conditions, such as structures, such as resin to be used, the kind and addition amount of an additive, a draw ratio, and the residual volatile matter at the time of peeling.

In this specification, Re ((lambda)) and Rth ((lambda)) represent the in-plane retardation in the wavelength (lambda), and the retardation of the thickness direction, respectively. Re (λ) is measured by injecting light having a wavelength of λ nm in the film normal direction in KOBRA 21ADH (manufactured by Oji Measuring Instruments Co., Ltd.). At the time of the selection of the measurement wavelength λ nm, the wavelength selection filter can be replaced manually or the measured value can be converted into a program or the like and measured. When the film to be measured is represented by the index ellipsoid of a single axis or a biaxial axis, Rth (λ) is calculated by the following method. Rth (λ) refers to Re (λ) as the in-plane slow axis (as determined by KOBRA 21ADH) as the inclination axis (rotation axis) (when there is no ground axis, any direction in the film plane is the rotation axis) Six points of light were measured by injecting light having a wavelength of λ nm from the inclined direction in 10-degree steps from the normal direction to the 50-degree one-side direction with respect to the film normal of, and the measured retardation value and the assumed refractive index average KOBRA 21ADH is calculated based on the input film thickness value. In addition, a slow axis is made into the inclination axis (rotation axis) (when there is no ground axis, arbitrary direction in a film plane shall be a rotation axis), the retardation value is measured from arbitrary 2 directions, and the hypothesis value of the value and an average refractive index And based on the input film thickness value, Rth can also be computed from following formula (1) and formula (2). Here, the assumption of the average refractive index may be a polymer handbook (JOHN WILEY & SONS, INC) or a value of a catalog of various optical films. If the value of the average refractive index is not already known, it can be measured with an Abbe refractometer. The value of the average refractive index of a main optical film is illustrated below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), polystyrene (1.59). By inputting the assumption values of these average refractive indices and the film thickness, KOBRA 21ADH calculates nx, ny, nz. From the calculated nx, ny and nz, Nz = (nx-nz) / (nx-ny) is further calculated.

Here, said Re ((theta)) shows the retardation value in the direction which inclined angle (theta) from a normal line direction.

Rth = ((nx + ny) / 2-nz) × d --- Equation (2)

Moreover, at this time, although the average refractive index n is needed as a parameter, this used the value measured by the Abbe refractometer ("Abe refractometer 2-T" by Atago Co., Ltd.).

Next, the polarizing plate which has the protective film for polarizing plates and optical compensation film which have the stretched film of this invention mentioned above, and this protective film for polarizing plates is demonstrated.

(Retardation Film-Optical Compensation Film)

When using a stretched film as retardation film, the range of Re and Rth differs according to the kind of retardation film, and there exists various requirements. It is preferable to use as an optical compensation film. The optical compensation film of this invention may be the stretched film itself of this invention, and may have another structural layer mentioned later. Moreover, it is preferable that the molecule | numerator contains a substituent with a large polarization ratio in a suitable ratio.

(Protective film for polarizing plate)

When using the stretched film of this invention as a protective film for polarizing plates, 5 nm or less is preferable and, as for in-plane retardation (Re), 3 nm or less is more preferable. Thickness direction retardation (Rth) FIG. 50 nm or less is preferable, 35 nm or less is more preferable, 10 nm or less is especially preferable.

The protective film for polarizing plates of this invention may be the stretched film itself of this invention, and may have another structural layer mentioned later.

(Polarizing plate)

The polarizing plate usually has a polarizer and two transparent protective films arranged on both sides thereof. And the polarizing plate of this invention uses the protective film for polarizing plates of this invention as both or one protective film. When using the protective film for polarizing plates of this invention only in one side, you may use a normal cellulose acetate film etc. for the other protective film. The polarizer includes an iodine polarizer and a dye polarizer or a polyene polarizer using a dichroic dye. An iodine type polarizer and a dye type polarizer are generally manufactured using a polyvinyl alcohol (PVA) type film. Although PVA is a polymer material which saponified polyvinyl acetate, it may contain the component copolymerizable with vinyl acetate, such as unsaturated carboxylic acid, unsaturated sulfonic acid, olefins, and vinyl ether, for example. Moreover, modified PVA containing an acetacetyl group, a sulfonic acid group, a carboxyl group, an oxyalkylene group, etc. can also be used.

Although the saponification degree of PVA is not specifically limited, From a viewpoint of solubility, etc., 80-100 mol% is preferable and 90-100 mol% is especially preferable. Moreover, although the polymerization degree of PVA is not specifically limited, 1000-10000 are preferable and 1500-5000 are especially preferable.

The syndiotacticity of PVA is preferably 55% or more in order to improve durability as described in Japanese Patent No. 2978219, but 45 to 52.5% described in Japanese Patent No. 3317494 can also be preferably used.

When using the stretched film of this invention as a protective film for polarizing plates and a retardation film, it is preferable to surface-treat as mentioned later to a film, and after that, to bond a film process surface and a polarizer using an adhesive agent. A polarizing plate is comprised by the polarizer and the protective film which protects both surfaces, Moreover, it is comprised by bonding a protective film to one surface of this polarizing plate, and a separate film to the opposite surface. A protective film and a separate film are used for the purpose of protecting a polarizing plate at the time of a polarizing plate shipment, a product inspection, etc. In this case, a protective film is bonded for the purpose of protecting the surface of a polarizing plate, and is used for the opposite surface side of the surface which bonds a polarizing plate to a liquid crystal plate. Moreover, a separator film is used for the purpose of covering the contact bonding layer bonded to a liquid crystal plate, and is used for the surface side which bonds a polarizing plate to a liquid crystal plate.

It is preferable to bond together the bonding method with respect to the polarizer of the protective film for polarizing plates of this invention so that the transmission axis of a polarizer may match the slow axis of the protective film for polarizing plates of this invention. Moreover, as a result of evaluating the polarizing plate manufactured under polarizing plate cross nicol, when the orthogonal precision of the slow axis of the protective film for polarizing plates of this invention, and the absorption axis (axis orthogonal to a transmission axis) of a polarizer is larger than 1 degree, polarizing plate cross nicol It was found that the polarization degree under the performance was reduced to generate light leakage. In this case, when combined with a liquid crystal cell, sufficient black level and contrast will not be obtained. Therefore, the shift | offset | difference of the direction of the principal refractive index nx of the protective film for polarizing plates of this invention, and the direction of the transmission axis of a polarizing plate is 1 degrees or less, Preferably it is within 0.5 degrees.

UV3100PC (made by Shimadzu Corporation) can be used for the measurement of single-plate transmittance TT, parallel transmittance PT, and orthogonal transmittance CT of a polarizing plate. In the measurement, it measures in the range of 380 nm-780 nm, and the average value of 10 times of measurement can be used for a single plate, a parallel, and an orthogonal transmittance | permeability.

It is preferable that the amount of change of a polarizing plate durability test before and after a test is small. For example, about the polarization degree of a polarizing plate, two polarizing plates are installed in 60 degreeC and 90% RH under cross nicol, and durability can be evaluated by comparing the light transmittance after 500 hours with the transmittance before a test.

Change rate of transmittance, that is, {(light transmittance at cross nicol after polarizing plate durability test)-(light transmittance at cross nicol before polarizing plate durability test)} / (light transmittance at cross nicol before polarizing plate durability test) × 100 (%) The smaller the value of, the better. The value of is preferably 0.5% or less.

(Surface Treatment of Stretched Film)

In order to improve the adhesiveness with a polarizer, the protective film for polarizing plates of this invention surface-treats the surface of a stretched film. As for the surface treatment, any method may be used as long as the adhesiveness can be improved. Examples of preferred surface treatments include glow discharge treatment, ultraviolet irradiation treatment, corona treatment, and flame treatment. The glow discharge treatment herein refers to a so-called low temperature plasma occurring under a low pressure gas. In the present invention, plasma treatment under atmospheric pressure is also preferable. In addition, details of the glow discharge treatment are described in the specifications of US Pat. No. 3,346,335, US Pat. 3761299, US Pat. No. 40,2769, and UK Pat. The method of Unexamined-Japanese-Patent No. 59-556430 which uses only the gas species generate | occur | produced in a container by discharge-gas atmosphere composition receiving a discharge process by the polyester support itself after a discharge start is also used. Moreover, when performing a vacuum glow discharge process, the method of Unexamined-Japanese-Patent No. 60-16614 which carries out a discharge process by making the surface temperature of a film into 80 degreeC or more and 180 degrees C or less can also be applied.

The vacuum degree during the glow discharge treatment is preferably 0.5 Pa to 3000 Pa, more preferably 2 Pa to 300 Pa. The voltage is preferably between 500 V and 5000 V, more preferably 500 V to 3000 V. The discharge frequency to be used is from DC to thousands of MHz, more preferably from 50 Hz to 20 MHz, still more preferably from 1 KHz to 1 MHz. The discharge treatment strength is preferably from 0.01 KV · A · min / m 2 to 5 KV · A · min / m 2, and more preferably 0.15 KV · A · min / m 2 to 1 KV · A · min / m 2.

In this invention, it is also preferable to perform an ultraviolet irradiation method as surface treatment. For example, it can carry out by the processing methods as described in each of Unexamined-Japanese-Patent No. 43-2603, 43-2604, and 45-3828. The mercury lamp is a high pressure mercury lamp made of a quartz tube, and preferably has a wavelength of 180 to 380 nm. About the method of ultraviolet irradiation, the high pressure mercury lamp lamp whose main wavelength is 365 nm can use a light source as long as there is no problem in the performance of a support body that surface temperature of a protective film rises to around 150 degreeC. When low temperature treatment is required, a low pressure mercury lamp having a 254 nm dominant wavelength is preferable. It is also possible to use an ozoneless type high pressure mercury lamp and a low pressure mercury lamp. Regarding the amount of light to be treated, the greater the amount of light to be treated, the more the adhesion between the film and the polarizer is improved. However, as the amount of light increases, the film becomes colored and weak. Therefore, the high-pressure mercury lamp whose main wavelength is 365 nm is preferably 20 mJ / cm 2 to 10000 mJ / cm 2, more preferably 50 mJ / cm 2 to 2000 mJ / cm 2. In the case of the low-pressure mercury lamp whose main wavelength is 254 nm, the irradiation light quantity is 100 mJ / cm <2> -10000 mJ / cm <2>, More preferably, it is 300 mJ / cm <2> -1500 mJ / cm <2>.

Moreover, in this invention, it is also preferable to perform corona discharge treatment as surface treatment. For example, the process of the thing of each of Unexamined-Japanese-Patent No. 39-12838, Unexamined-Japanese-Patent No. 47-19824, Unexamined-Japanese-Patent No. 48-28067, and Unexamined-Japanese-Patent No. 52-42114, etc. are processed. It can carry out by a method. As the corona discharge treatment apparatus, a solid state corona treatment machine manufactured by Pillar, a LEPEL surface treatment machine, a VETAPHON type treatment machine, or the like can be used. The treatment can be carried out at normal pressure in air. The discharge frequency at the time of processing is 5KV-40KV, More preferably, it is 10KV-30KV, The waveform is preferably an AC sine wave. The gap transparent lance of an electrode and a dielectric roll is 0.1 mm-10 mm, More preferably, it is 1.0 mm-2.0 mm. The discharge is processed above the dielectric support roller formed in the discharge zone, and the throughput is from 0.34 KV · A · min / m 2 to 0.4 KV · A · min / m 2, more preferably from 0.344 KV · A · min / m 2. 0.38 KV · A · min / m2.

In this invention, it is also preferable to perform flame processing as surface treatment. The gas to be used may be any of natural gas, liquefied propane gas and city gas, but the mixing ratio with air is important. This is because the effect of surface treatment by the flame treatment is considered to be caused by the plasma containing active oxygen, and the point is how much the activity (temperature) and oxygen of the plasma, which are important properties of the flame, are. The governing factor of this point is gas / oxygen consumption, and when the reaction is performed without excess or deficiency, the energy density is the highest and the plasma activity is increased. Specifically, the preferred mixing ratio of natural gas / air is 1/6 to 1/10 in volume ratio, preferably 1/7 to 1/9. Moreover, in the case of liquefied propane gas / air, it is 1 / 14-1 / 22, Preferably 1 / 16-1 / 19, In the case of city gas / air, 1 / 2-1 / 8, Preferably 1/3 It is -1/7. In addition, the flame treatment amount may be performed in a range of 1 Kcal / m 2 to 50 Kcal / m 2, more preferably 3 Kcal / m 2 to 20 Kcal / m 2. The distance between the tip of the flame resistant flame of the burner and the film may be 3 cm to 7 cm, more preferably 4 cm to 6 cm. The nozzle shape of the burner is a ribbon type of Prince Burner (USA), a multi-blood type of Wise (USA), a ribbon type of Aerogen (UK), and a zigzag multi-blood type of Kasuga Electric (Japan). The zigzag multi-blood type of Koike oxygen (Japan) is preferable. The back-up roll which supports a film in flame processing is a hollow roll, It is preferable to carry out water cooling by passing cooling water, and to always process at a constant temperature of 20-50 degreeC.

About the degree of surface treatment, although the preferable range also differs according to the kind of surface treatment and the kind of resin to be used, as a result of surface treatment, the contact angle with the surface pure water of the protective film which surface-treated was less than 50 degrees. desirable. As for the said contact angle, it is more preferable that they are 25 degrees or more and less than 45 degrees. When the contact angle with the pure water of the protective film surface exists in the said range, the adhesive strength of a protective film and a polarizing film will become favorable.

(glue)

When bonding together the polarizer which consists of a polyvinyl alcohol-type film, and the stretched film processed as a protective film for polarizing plates, it is preferable to use the adhesive agent containing a water-soluble polymer. As the water-soluble polymer preferably used for the adhesive, N-vinylpyrrolidone, acrylic acid, methacrylic acid, maleic acid, β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, vinyl alcohol, methyl vinyl ether Homopolymers or copolymers having ethylenically unsaturated monomers, such as vinyl acetate, acrylamide, methacrylamide, diacetone acrylamide and vinylimidazole as components, and polyoxyethylene, polyoxypropylene, poly-2-methyl Oxazoline, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, gelatin and the like. In this invention, PVA and gelatin are preferable among these.

The preferable PVA characteristic at the time of using PVA for an adhesive agent is the same as the preferable characteristic of PVA used for the polarizer mentioned above. In this invention, it is preferable to use a crosslinking agent further. A boric acid, a polyhydric aldehyde, a polyfunctional isocyanate compound, a polyfunctional epoxy compound, etc. are mentioned, The crosslinking agent used preferably together when PVA is used for an adhesive agent, Boric acid is especially preferable in this invention. When gelatin is used for the adhesive, so-called lime-treated gelatin, acid-treated gelatin, enzyme-treated gelatin, gelatin derivatives, denatured gelatin and the like can be used. Among these gelatins, preferably used are lime treated gelatin and acid treated gelatin. In the case of using gelatin in the adhesive, as a crosslinking agent to be preferably used together, an active halogen compound (such as 2,4-dichlor-6-hydroxy-1,3,5-triazine and its sodium salt) and active vinyl Compound (1,3-bisvinylsulfonyl-2-propanol, 1,2-bisvinylsulfonylacetamide) ethane, bis (vinylsulfonylmethyl) ether or vinyl polymer having vinylsulfonyl group in the side chain) , N-carbamoylpyridinium salts ((1-morpholinocarbonyl-3-pyridinio) methanesulfonate, etc.) or haloamidinium salts (1- (1-chloro-1-pyridinomethylene) Pyrrolidinium 2-naphthalenesulfonate, etc.) etc. are mentioned. In the present invention, an active halogen compound and an active vinyl compound are particularly preferably used.

The preferable addition amount of the crosslinking agent in the case of using the above-mentioned crosslinking agent together is 0.1 mass part or more and less than 40 mass parts with respect to 100 mass parts of water-soluble polymers in an adhesive agent, More preferably, it is 0.5 mass part or more and less than 30 mass parts to be. It is preferable to form an adhesive bond layer by applying an adhesive agent to at least one surface of a protective film or a polarizer, and to bond, and to apply an adhesive agent to the surface treatment surface of a protective film, to form an adhesive bond layer, and to bond it to the surface of a polarizer. desirable. 0.01 micrometer-5 micrometers are preferable, and, as for an adhesive bond layer thickness, 0.05 micrometer-3 micrometers are especially preferable.

(Reflective layer)

It is preferable to form functional layers, such as an antireflection layer, in the transparent protective film arrange | positioned on the opposite side to a liquid crystal cell of a polarizing plate. In particular, in the present invention, the anti-reflection layer in which the light scattering layer and the low refractive index layer are laminated in this order on the transparent protective film or the anti-reflection layer in which the medium refractive index layer, the high refractive index layer, and the low refractive index layer are laminated in this order on the transparent protective film is It is preferably used. Their details are described in published publication 2001-1745 (issued March 13, 2001).

(Other layers of antireflective layer)

Moreover, you may form a hard-coat layer, a front-scattering layer, a primer layer, an antistatic layer, an undercoat layer, a protective layer, etc.

(Hard coat layer)

The hard coat layer is formed on the surface of the transparent support in order to impart physical strength to the transparent protective film on which the antireflection layer is formed. In particular, it is preferable to form between a transparent support body and the said high refractive index layer. It is preferable that a hard-coat layer is formed by the crosslinking reaction of a curable compound of light and / or heat, or a polymerization reaction. As a curable functional group, a photopolymerizable functional group is preferable, and the organic alkoxy silyl compound is preferable for the organometallic compound containing a hydrolysable functional group.

As a specific example of these compounds, the thing similar to what was illustrated by the high refractive index layer is mentioned. As a specific structural composition of a hard-coat layer, what was described in Unexamined-Japanese-Patent No. 2002-144913, Unexamined-Japanese-Patent No. 2000-9908, International Publication No. 00/46617 pamphlet, etc. are mentioned, for example.

The high refractive index layer can also serve as a hard coat layer. In such a case, it is preferable to form by disperse | distributing microparticles | fine-particles finely and containing in a hard-coat layer using the method described by the high refractive index layer.

The hard coat layer may also serve as an antiglare layer containing particles having an average particle diameter of 0.2 μm to 10 μm and imparting an antiglare function (antiglare function).

The film thickness of a hard coat layer can be designed suitably according to a use. It is preferable that the film thickness of a hard-coat layer is 0.2 micrometer-10 micrometers, More preferably, they are 0.5 micrometer-7 micrometers.

In the pencil hardness test according to JIS K 5400, the strength of the hard coat layer is preferably H or more, more preferably 2 H or more, and most preferably 3 H or more. In the taper test according to JIS K 5400, the smaller the amount of abrasion of the test pieces before and after the test, the more preferable.

(Antistatic layer)

When forming an antistatic layer, it is preferable to provide electroconductivity whose volume resistivity is ^10-8 ohm ^- cm- ³ or less. Depending on the use of hygroscopic substances, water-soluble inorganic salts, surfactants of any kind, cationic polymers, anionic polymers, colloidal silicas, etc., the volume resistivity of 10 ^-8 Ωcm ^{- 3} can be given, but the temperature-humidity dependence is large, At low humidity, there is a problem in that sufficient conductivity cannot be secured. Therefore, as an antistatic layer material, a metal oxide is preferable. Although some metal oxides are colored, when these metal oxides are used as an antistatic layer material, the whole film is colored and it is unpreferable. Zn, Ti, Al, In, Si, Mg, Ba, Mo, W, or V can be given as a metal which forms a metal oxide without coloring, and it is preferable to use the metal oxide which has this as a main component. As a specific example, ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , SiO ₃ , MgO, BaO, MoO ₃ , V ₂ O ₅ , or a composite oxide thereof is preferable, and in particular ZnO, TiO ₂ and SnO ₂ are preferred. Examples containing hetero atoms include, for example, additives such as Al and In for ZnO, addition of Sb, Nb and halogen elements for SnO ₂ , and addition of Nb and TA for TiO ₂ . effective. As described in Japanese Patent Application Laid-Open No. 59-6235, a material in which the metal oxide is attached to another crystalline metal particle or fibrous material (for example, titanium oxide) may be used. In addition, although the volume resistance value and the surface resistance value are different physical property values and cannot be compared simply, in order to ensure the conductivity of 10 ^-8 Ωcm ^-3 or less in the volume resistance value, the antistatic layer is generally 10 ^-10 Ω / □. What is necessary is just to have the following surface resistance values, More preferably, it is ^10-8 ohms / square. The surface resistance value of an antistatic layer needs to be measured as a value when the antistatic layer is made into the outermost layer, and can be measured in the middle of forming the laminated | multilayer film described in this specification.

Next, the liquid crystal display device of this invention which has at least any one of the said stretched film, the said protective film for polarizing plates, the said optical compensation film, and the said polarizing plate is demonstrated.

(Liquid crystal display device)

The stretched film of this invention, the optical compensation film which has this film, and the polarizing plate using this film can be used for the liquid crystal cell of various display modes, and a liquid crystal display device. Twisted Nematic (TN), In-Plane Switching (IPS), Ferroelectric Liquid Crystal (FLC), Anti-ferroelectric Liquid Crystal (AFLC), Optimal Compensatory Bend (OCB), Super Twisted Nematic (STN), Vertically Aligned (VA), and Various display modes such as HAN (Hybrid Aligned Nematic) and ECB (Electrically Controlled Birefringence) have been proposed. Among these, it can use suitably for IPS mode, ECB mode, OCB mode, or VA mode.

(IPS type liquid crystal display device and ECB type liquid crystal display device)

The stretched film of this invention is especially advantageous also used as a support film of the optical compensation sheet of an IPS type liquid crystal display device and an ECB type liquid crystal display device which have a liquid crystal cell of an IPS mode and an ECB mode, or a polarizing plate. These modes are embodiments in which the liquid crystal material is oriented almost in parallel during black display. The liquid crystal molecules are aligned in parallel with the substrate surface in a state where no voltage is applied, and the black display is performed. In these aspects, the polarizing plate using the stretched film of the present invention contributes to enlargement of the viewing angle and improvement of contrast.

(OCB type liquid crystal display device)

The liquid crystal cell of OCB mode is a liquid crystal display device using the liquid crystal cell of the bend alignment mode which orientates rod-like liquid crystalline molecules substantially (symmetrically) in the upper and lower portions of the liquid crystal cell. The liquid crystal cell of the OCB mode is disclosed in the specifications of US Pat. No. 4,458,525 and 5410422. Since the rod-shaped liquid crystal molecules are symmetrically aligned at the top and bottom of the liquid crystal cell, the liquid crystal cell in the bend alignment mode has a magneto-optical compensation function. Therefore, this liquid crystal mode is also called OCB (Optically Compensatory Bend) liquid crystal mode. The liquid crystal display device of the bend alignment mode has an advantage that the response speed is high.

(VA type liquid crystal display device)

In the liquid crystal cell of VA mode, when a voltage is not applied, rod-shaped liquid crystalline molecules are orientated substantially vertically.

In the liquid crystal cell of VA mode, (1) VA mode liquid crystal cell which aligns rod-shaped liquid crystalline molecules substantially vertically when no voltage is applied, and is substantially horizontally aligned when voltage is applied. (2) Liquid Crystal Cell (in MVA mode) (SID97, Digest of tech.Papers (Preliminary Notice) 28 (1997) 845) Base material), (3) Liquid crystal cell of the mode (n-ASM mode) which makes a rod-shaped liquid crystalline molecule substantially vertically orientate at the time of voltage no application, and twist-domain orientation at the time of voltage application. 59 (1998)) and (4) liquid crystal cells in SURVAIVAL mode (presented by LCD International 98).

The liquid crystal display device of VA mode consists of a liquid crystal cell and two polarizing plates arrange | positioned at both sides. The liquid crystal cell carries liquid crystal between two electrode substrates. In one aspect of the transmissive liquid crystal display device of the present invention, one sheet of the optical compensation film of the present invention is disposed between the liquid crystal cell and one polarizing plate, or two sheets are disposed between the liquid crystal cell and both polarizing plates.

In another aspect of the transmissive liquid crystal display device of the present invention, an optical compensation film having the stretched film of the present invention is used as the transparent protective film of the polarizing plate disposed between the liquid crystal cell and the polarizer. That is, the transparent protective film of a polarizing plate can also serve as an optical compensation film. Said optical compensation film may be used only for the transparent protective film (between liquid crystal cell and polarizer) of one polarizing plate, or the said optical compensation film may be used for two transparent protective films (between liquid crystal cell and polarizer) of both polarizing plates. You may use it. When using the said optical compensation film only in one polarizing plate, it is especially preferable to use as a liquid crystal cell side protective film of the backlight side polarizing plate of a liquid crystal cell. It is preferable that bonding to a liquid crystal cell makes the stretched film of this invention the VA cell side. The other protective film may be a cellulose acylate film usually used. For example, 40 micrometers-80 micrometers are preferable, and commercially available KC4UX2M (40 micrometers made by Konica Opt Co., Ltd.), KC5UX (60 micrometers made by Konica Opt Co., Ltd.), TD80 (80 micrometers made by Fuji Photo Film), etc. are mentioned. Although it does mention, it is not limited to these.

In the liquid crystal display device and TN liquid crystal display device of OCB mode, an optical compensation film is used for viewing angle expansion. As an optical compensation film for OCB cells, what formed the optically anisotropic layer which fixed and fixed the discotic liquid crystal on the optical uniaxial or biaxial film is used. As an optical compensation film for TN cells, what formed the optically anisotropic layer which fixed and fixed the discotic liquid crystal on the film which has an optical axis in optical isotropic or a thickness direction is used. The stretched film of this invention is also useful in manufacture of the said optical compensation film for OCB cells, and the optical compensation film for TN cells.

Example

EMBODIMENT OF THE INVENTION Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these.

<Synthesis of Cyclic Polyolefin Polymer K-1>

100 parts by mass of purified toluene and 100 parts by mass of norbornene carboxylic acid methyl ester were added to the reaction kiln. Then 25 mmol% ethylhexanoate-Ni dissolved in toluene (large monomer mass), 0.225 mol% tri (pentafluorophenyl) boron (large monomer mass) and 0.25 mol% triethylaluminum dissolved in toluene (large monomer mass) Was added to the reaction kiln. It was made to react for 18 hours, stirring at room temperature. After the reaction was completed, the reaction mixture was poured into excess ethanol to produce a polymer precipitate. The cyclic polyolefin polymer K-1 obtained by refining the precipitate was vacuum dried and dried at 65 ° C for 24 hours.

The obtained polymer was dissolved in tetrahydrofuran and the molecular weight measured by GPC was measured. As a result, the number average molecular weight in terms of polystyrene was 79,000, and the weight average molecular weight was 205,000. The refractive index measured by the Abbe refractometer was 1.52.

Example  One

The following composition was put into a mixing tank and stirred, and after dissolving each component, it filtered with the filter paper of 34 micrometers of average hole diameters, and the sintered metal filter of 10 micrometers of average hole diameters, and prepared the dope for film forming.

Cyclic polyolefin polymer K-1 100 parts by mass

325 parts by mass of dichloromethane

28.5 parts by mass of methanol

20 parts by mass of the following additive A

10 parts by mass of the following additive B

0.3 parts by mass of the following additive E

The dope was cast with a band softener. The film peeled off from the band by the amount of residual solvent about 30 mass% was shot and dried by hot air of 140 degreeC, maintaining with a tenter. Then, it shifted from tenter conveyance to roll conveyance, and it dried at 120 degreeC-140 degreeC, and obtained the 1440 mm width cyclic olefin resin film. The film thickness of the film was 25 micrometers.

[Manufacture of Film]

In the casting method of the solution, the prepared dope was cast with a band softener.

Although extending | stretching was performed by the tenter method, you may extend | stretch the film wound up once again, and in that case, (1) the film wound up is sent, (2) it puts in the extending zone adjusted to temperature T, and (3) extending | stretching And (4) it implemented by the process of winding up again.

The manufacturing conditions of the stretched film A thus obtained are shown in Table 2. Moreover, the following optical characteristics of the stretched film A were investigated. The results are shown in Table 2. Re and Rth were measured by the method mentioned above in (lambda) = 590 nm.

(1) Initial values of Re and Rth (Re (I), Rth (I))

(2) Re, Rth (Re (T), Rth (T)) after leaving at temperature T for 3 minutes while holding at least two sides of the film.

(3) the value of (Rth (T) / Rth (I))

(4) weight loss rate (%)

In the differential thermal thermogravimetry device (TG / DTA): SII, type EXSTAR6000 TG / DTA, the weight loss rate was increased to temperature T at a rate of 20 ° C./min, and then maintained at temperature T for 60 minutes. It was calculated by measuring the weight loss at the time. % Weight loss = [{(Initial film weight)-(film weight after 60 minutes hold at temperature T))} / (initial film weight)] × 100

(5) Initial value of film haze (%)

The haze measured the film sample 40 mm x 80 mm at 25 degreeC and 60% RH by the haze meter "HGM-2DP" (made by Suga Test Machine Co., Ltd.) according to JIS K-6714.

(6) Haze (%) after leaving at temperature T for 3 minutes in a state where at least two sides of the film are gripped (haze after heat treatment)

(7) Optical Properties of Stretched Film A (Re, Rth)

(8) NZ measured and calculated Re and Rth of the produced film.

(9) Changes in optical properties after treatment at 60 ° C for 90% RH for 24 hours

About the film after extending | stretching, it controlled humidity for 24 hours on 25 degreeC 60% RH conditions, and measured Re and Rth (respectively, Re-Before and Rth-Before).

In addition, after the said stretched film was humidified for 24 hours on 60 degreeC 90% RH conditions, it was taken out from thermostat conditions, and it was humidified for 24 hours under 25 degreeC 60% RH conditions, and Re and Rth were measured (Re-After, Rth, respectively). -After). ΔRe (60 w) and ΔRth (60 w) were calculated by the following equation.

ΔRe (60 w) = (Re-After)-(Re-Before)

ΔRth (60 w) = (Rth-After)-(Rth-Before)

Evaluation was performed based on the following criteria.

5 ㎚, 또한, |ΔRth(60 w)|

5 ㎚◎: | ΔRe (60 w) |

5 nm, and | ΔRth (60 w) |

5 nm

10 ㎚, 또한, 5 ㎚ ＜ |ΔRth(60 w)|

10 ㎚○: 5 nm <| ΔRe (60 w) |

10 nm, and 5 nm <| ΔRth (60 w) |

10 nm

Δ: 10 nm <| ΔRe (60w) |, and 10 nm <| ΔRth (60w) |

(10) film wavelength dispersion

Re (λ) and Rth (λ) each represent an in-plane retardation and a retardation in the thickness direction at the wavelength λ. Re (λ) is measured by injecting light having a wavelength of λ nm in the film normal direction in KOBRA 21ADH (manufactured by Oji Measuring Instruments Co., Ltd.).

Film wavelength dispersion (ΔRe) was determined by Re (440) -Re (630).

(11) VA polarizer compatibility

The obtained film was mounted on the liquid crystal display device of VA mode as a protective film for polarizing plates, and it used the measuring instrument (EZ-contrast 160D, ELDIM Co., Ltd.) in the black display state in 25 degreeC 60% RH at 45 degrees of azimuth angles. The black luminance (inclined black luminance) at the polar angle of 60 ° was measured. The measured gradient blackness was evaluated according to the following evaluation criteria.

Inclined black brightness was 0.4 cd / m <2> or less as the polarizing plate suitability for VA ((circle)). Since the film did not have VA aptitude, it was set as (-) not to test.

Examples 2 to 57 and Comparative Examples 1 to 8

Except having changed into the manufacturing conditions shown in Tables 2-5 using the polymer shown in Tables 2-5, it carried out similarly to Example 1, the stretched film was produced, and each evaluation was performed. The results are shown in Tables 6-9.

Additives A-G, X, and Y are as follows.

Additive A: Toa Synthetic Co., Ltd., trade name UH2041

Additive B: Toa Synthetic Fiber, trade name UH2180

[Formula 6]

[Formula 7]

Additive E: Ciba company make, brand name IRG1010

Additive F: Triphenyl Phosphate

Additive G: Biphenyldiphenyl Phosphate

Additive X: polyester-based polymer P-64

Additive Y: polyester-based polymer P-6

In Tables 2-5, the addition amount of an additive is a mass part of an additive with respect to 100 mass parts of polymers.

Industrial availability

The stretched film manufactured by the manufacturing method of this invention is equipped with the optical characteristic useful as each functional film, and can be used suitably as a protective film for polarizing plates, for example.

This application is based on the JP Patent application (Japanese Patent Application 2008-94235) of an application on March 31, 2008, The content is taken in here with reference.

Claims (10)

The film formed by the solution casting method having an initial value of 30 nm or more in the retardation in the thickness direction is stretched at a temperature T satisfying the following formula I), and measured by TG-DTA at the temperature T. A stretched film, characterized in that a weight loss rate of about 60 minutes is 5% or less.
Equation I) 0.2

(Rth (T) / Rth (I))

0.9
In formula I), Rth (T) is a retardation value of the thickness direction measured at (lambda) = 590 nm of the said film after leaving it for 3 minutes in temperature T in the state which hold | maintained at least 2 sides of the said film, and Rth (I ) Is the initial value of the retardation in the thickness direction measured at λ = 590 nm of the film. In addition, the said weight reduction rate is calculated | required by weight reduction rate (%) = [{(initial film weight)-(film weight after holding for 60 minutes at temperature T)} / (initial film weight)] x100 . The method of claim 1,
The stretched film in which the optical characteristic after extending | stretching satisfy | fills the following conditions.
1.75

Rth / Re + 0.5

5 (wherein Rth is a retardation value in the thickness direction measured at λ = 590 nm, and Re is an in-plane retardation value measured at λ = 590 nm) The method according to claim 1 or 2,
The stretched film whose said film is a cyclic olefin resin film. The method according to claim 1 or 2,
The stretched film which the said film has a C2-C4 acyl substituent and consists of cellulose resin whose substitution degree of an acyl group is 2.1-2.7. The method of claim 4, wherein
The stretched film in which the said film has a C2-C4 acyl substituent and consists of cellulose resin whose substitution degree of an acyl group is 2.3-2.6. 6. The method according to any one of claims 1 to 5,
Optical properties, 25 nm

Re

100 nm, 50 nm

Rth

Stretched film which satisfy | fills 300 nm. (Re is the in-plane retardation value measured at λ = 590 nm, and Rth is the retardation value in the thickness direction measured at λ = 590 nm) 6. The method according to any one of claims 1 to 5,
Optical properties, 50 nm

Re

70 nm, 90 nm

Rth

Stretched film which satisfy | fills 120 nm. (Re is the in-plane retardation value measured at λ = 590 nm, and Rth is the retardation value in the thickness direction measured at λ = 590 nm) The method according to any one of claims 1 to 7,
The stretched film in which the said film contains a retardation regulator. As a polarizing plate which has a polarizer and two protective films on both sides of the polarizer,
At least one of said two protective films is a stretched film in any one of Claims 1-8. It has a process of extending | stretching the film formed by the solution casting | flow_spreading method which has the initial value whose retardation of thickness direction is 30 nm or more at the temperature T which satisfy | fills following formula I), and also it is TG-DTA in said temperature T. The weight reduction rate for 60 minutes measured is 5% or less, The manufacturing method of the stretched film characterized by the above-mentioned.
Equation I) 0.2

(Rth (T) / Rth (I))

0.9
In formula I), Rth (T) is a retardation value of the thickness direction measured at (lambda) = 590 nm of the said film after leaving it for 3 minutes in temperature T in the state which hold | maintained at least 2 sides of the said film, and Rth (I ) Is the initial value of the retardation in the thickness direction measured at λ = 590 nm of the film. In addition, the said weight reduction rate is calculated | required by weight reduction rate (%) = [{(initial film weight)-(film weight after holding for 60 minutes at temperature T)} / (initial film weight)] x100 .