JP5357468B2 - Method for producing thermoplastic resin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film good in optical property expression, having a tilted structure of a phase difference, and good in durability of an optical characteristic, and a process of manufacturing the same. <P>SOLUTION: The process of manufacturing the film includes: a step of melt kneading a composition containing a thermoplastic resin and additive; a step of cooling to solidify the melt kneaded composition to a glass transition temperature or below of the thermoplastic resin; a step of melt extruding a thermoplastic resin-containing composition containing the solidified composition from a die; and a step of continuously clamping to form the melt extruded molten article between a first clamping plane and second clamping plane comprising a clamping device, in a film-shape. Pressure applied to the molten article with the clamping device is 20-120 MPa, and moving speed of the first clamping plane is made faster than moving speed of the second clamping plane. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a thermoplastic resin film and a method for producing the same. The present invention also relates to a polarizing plate and a liquid crystal display device having the film.

  In recent years, various films have been developed with the rise of the liquid crystal display market. For example, Patent Documents 1 to 3 disclose tilted retardation films.

  For example, Patent Document 1 discloses that a film is passed between two rolls having different peripheral speeds, thereby applying a shearing force to the film to create a film with an inclined optical axis, and a TN type liquid crystal display. Applications are described. However, the method described in Document 1 has problems such as large variations in optical characteristics of the film and easy contact scratches on the film surface. Nor did it suggest application to melts. On the other hand, in patent documents 2 and 3, the film thickness which solved the above-mentioned problem by pinching a melt using two rolls of a metal roll which may differ from a rubber roll and peripheral speed, and giving shearing force. It is described that an optical film of 100 to 150 μm can be obtained.

On the other hand, attention has been focused on pellets of thermoplastic resin raw materials, and methods for preparing resin pellets before use in melt film formation have recently been studied. For example, Patent Document 4 discloses a method of improving foreign matter failure and die line failure of a film by re-pelletizing resin raw material pellets and uniformly dispersing a powder additive such as a matting agent. Patent Document 5 discloses a thermoplastic resin pellet in which resin raw material pellets are prepared under specific conditions using a twin-screw extrusion kneader to suppress coloring and molecular weight reduction, and a method for producing the same.
JP-A-6-22213 JP 2007-38646 A JP 2007-237495 A JP 2007-268872 A JP 2007-269941 A

However, when the present inventors examined the production methods described in Patent Documents 1 to 3, there is a retardation characteristic, but the optical developability is low, and further, the optical characteristic of the produced optical film is the use environment temperature. It has been found that there is a problem that it changes with time due to temperature and humidity.
On the other hand, Patent Document 4 discloses a method of re-pelletizing resin raw material pellets and uniformly dispersing a powder additive such as a matting agent. However, in this document, optical characteristics and inclined structures required for widening the viewing angle are disclosed. Nothing is disclosed about the production of optical films having Patent Document 5 discloses a method for producing a film using a raw material obtained by re-pelletizing resin raw material pellets, but this document also discloses nothing about the production of an optical film having optical characteristics and an inclined structure required for viewing angle expansion. It has not been. When the present inventors examined the production methods described in Patent Documents 4 and 5, the optical development was poor, the phase difference gradient structure was insufficient, and the optical properties were insufficient. It was. That is, it was found that the durability of the optical characteristics is not improved by simply re-pelletizing.

  As described above, a method for producing a film having good optical expression, a phase difference gradient structure and good optical property durability has not been known so far, and a film having such properties can be produced. A method was desired.

  A first object of the present invention is to provide a film having a good optical development property, a phase difference gradient structure, and a good optical property durability, and a method for producing the same. A second object of the present invention is to provide a polarizing plate and a liquid crystal display device using the film.

The present inventors have conducted intensive research in view of the above-mentioned problems, and as a result, the optical expression is greatly improved by forming a film by applying high pressure between the clamping devices, and shearing while applying high pressure between the clamping devices. By forming a film by applying stress, a phase difference gradient structure can be obtained. Furthermore, surprisingly, when a film is formed by applying a high pressure between the sandwiching devices using a re-pelletized thermoplastic resin raw material, Re and Rth It came to discover that durability could be improved.
In particular, it is not clear what theory is the cause of fluctuations in the durability of Re and Rth when a film is exposed to a high temperature for a long period of time, but the dispersibility between thermoplastic resin and additives I found out. The reason why the resin and the additive are non-uniformly dispersed is that the dispersion of the additive changes with time (for example, the additive bleeds out to the film surface over time). ) And the dispersibility itself at the time of film formation is non-uniform (for example, the dispersion of the film surface and the inside of the film becomes non-uniform due to the volatilization of the additive during the film formation process) And so on. Accordingly, in the present invention, the thermoplastic resin raw material pellets and additives to be used are once melt-kneaded and then re-pelletized, so that the resin melt at the time of melt film formation (hereinafter also referred to as melt) can be uniformly formed. It has been found that the additive can be dispersed. As a result, it was found that the durability of Re and Rth of the obtained optical film having a large phase difference gradient structure can be improved by applying a certain range of high pressure to the resin melt between the clamping devices.
Furthermore, it is unclear what theory it is based on compared to the case of high pressure only (no shear stress is applied), but the durability of Re and Rth is significantly improved by applying shear stress while applying high pressure. As a result, the present invention has been achieved.
That is, the inventors have found that the above-described problems can be solved by the following means, and have completed the present invention described below.

[1] A step of melt-kneading a composition containing a thermoplastic resin and an additive, a step of cooling and solidifying the melt-kneaded composition below the glass transition temperature of the thermoplastic resin, and a solidified composition A step of melt-extruding a thermoplastic resin-containing composition containing the die from a die, and continuously pressing the melt-extruded melt between a first clamping surface and a second clamping surface constituting a clamping device to form a film A pressure applied to the melt by the clamping device is 20 MPa to 120 MPa, and the moving speed of the first clamping surface is made faster than the moving speed of the second clamping surface. A method for producing a thermoplastic film.
[2] The method for producing a thermoplastic resin film according to [1], wherein the composition containing the thermoplastic resin and an additive is a pellet.
[3] In the step of continuously pressing the melt-extruded melt between the first clamping surface and the second clamping surface constituting the clamping device to form a film, the clamping devices are mutually circumferential. The method for producing a film according to [1] or [2], wherein the two rolls have different speeds.
[4] The moving speed ratio between the first clamping surface and the second clamping surface of the clamping device defined by the following formula (1) is 0.75 to 0.99. 3] The method for producing a thermoplastic film according to any one of [3].
Movement speed ratio = speed of second clamping surface / speed of first clamping surface (1)
[5] In the step of melt-extruding the thermoplastic resin-containing composition containing the solidified composition from a die, the solidified composition is used in an amount of 30 to 100% by mass with respect to the entire thermoplastic resin-containing composition. The method for producing a thermoplastic film according to any one of [1] to [4], wherein:
[6] The method for producing a thermoplastic film according to any one of [1] to [5], wherein the solidified composition contains 0.1 to 20% by mass of the additive.
[7] The additive according to any one of [1] to [6], wherein the additive is at least one selected from a stabilizer, a plasticizer, inorganic fine particles, an ultraviolet absorber, and an optical adjusting agent. A method for producing a thermoplastic film.
[8] The thermoplastic resin is at least one selected from a cyclic olefin resin, a cellulose acylate resin, a polycarbonate resin, an acrylic resin, and a styrene resin. [7] The method for producing a thermoplastic film according to any one of [7].
[9] Absolute value of fluctuation of Re [0 °] around 500 hours in an environment of 90 ° C. relative humidity 10% and absolute value of fluctuation of Rth around 500 hours in an environment of 90% relative humidity 10% Is 0-10 nm, and further satisfies the following formulas (I) and (II).
10 nm ≦ Re [0 °] ≦ 300 nm Formula (I)
(In the formula (I), Re [0 °] represents the retardation in the front direction at a wavelength of 550 nm measured from the normal in the plane including the film tilt direction and the film normal.)
40 nm ≦ γ ≦ 300 nm (II) Formula γ = | Re [+ 40 °] −Re [−40 °] | Formula (II ′)
(In the formulas (II) and (II ′), Re [+ 40 °] represents retardation in the front direction measured from a direction inclined + 40 ° with respect to the normal, and Re [−40 °] represents the normal. Represents the retardation in the front direction measured from a direction tilted by −40 ° with respect to the film, where “the direction tilted by θ ° from the film normal” refers to the film surface direction by θ ° from the normal direction to the tilt direction. It is the direction inclined to
[10] The thermoplastic film as described in [9], wherein retardation Rth in the film thickness direction is 30 to 500 nm.
[11] A thermoplastic film produced by the method for producing a thermoplastic film according to any one of [1] to [8].
[12] A polarizing plate comprising at least one thermoplastic film according to any one of [9] to [11].
[13] A liquid crystal display device comprising at least one thermoplastic film according to any one of [9] to [11].

  The thermoplastic resin film of the present invention has good optical developability, has a phase difference gradient structure, and has good optical property durability. Therefore, it can be suitably used for a polarizing plate, particularly a polarizing plate for a liquid crystal display device. Moreover, according to the manufacturing method of the thermoplastic resin film of this invention, this film can be manufactured.

  Hereinafter, the present invention will be described in more detail. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value. In the present specification, the “film longitudinal direction” means the MD (machine direction) direction. In this specification, “screw length” represents the length from the thermoplastic resin supply port of the extruder to the screw tip, and is represented by L. In the present specification, “gel” is a modified crosslinked product of a thermoplastic resin produced during the melting step and represents a substance that is insoluble in a solvent.

[Thermoplastic resin film]
The thermoplastic resin film of the present invention (hereinafter also referred to as the film of the present invention) has an absolute value of fluctuation of Re [0 °] and a relative humidity of 10 ° %, The absolute value of the fluctuation of Rth before and after the lapse of 500 hours is 0 to 10 nm and satisfies the following formulas (I) and (II).
10 nm ≦ Re [0 °] ≦ 300 nm (I) Formula (In the formula (I), Re [0 °] is the front direction at a wavelength of 550 nm measured from the normal line in the plane including the film tilt direction and the film normal line. Represents retardation.)
40 nm ≦ γ ≦ 300 nm (II) Formula γ = | Re [+ 40 °] −Re [−40 °] | Formula (II ′)
(In the formulas (II) and (II ′), Re [+ 40 °] represents retardation in the front direction measured from a direction inclined + 40 ° with respect to the normal, and Re [−40 °] represents the normal. Represents the retardation in the front direction measured from a direction tilted by −40 ° with respect to the film, where “the direction tilted by θ ° from the film normal” refers to the film surface direction by θ ° from the normal direction to the tilt direction. It is the direction inclined to
Hereinafter, details of the film of the present invention will be described.

(In-plane retardation Re, γ)
The film of the present invention satisfies the following formulas (I) and (II).
10 nm ≦ Re [0 °] ≦ 300 nm Formula (I)
40 nm ≦ γ ≦ 300 nm Formula (II)
γ = | Re [+ 40 °] −Re [−40 °] | Formula (II ′)

  In this specification, the “direction inclined by θ ° from the film normal” is defined as a direction inclined in the film surface direction by θ ° from the normal direction to the inclination direction. That is, the normal direction of the film surface is a direction with an inclination angle of 0 °, and an arbitrary direction within the film surface is a direction with an inclination angle of 90 °.

The film of the present invention more preferably satisfies the following formulas (III) and (IV).
40 nm ≦ Re [0 °] ≦ 280 nm Formula (III)
60 nm ≦ γ ≦ 250 nm Formula (IV)
More preferably, the following formulas (V) and (VI) are satisfied.
70 nm ≦ Re [0 °] ≦ 250 nm Formula (V)
80 nm ≦ γ ≦ 180 nm Formula (VI)

(Thickness direction retardation Rth)
The film of the present invention preferably has a thickness direction retardation Rth defined by the following formula (A) of 30 to 300 nm.

式中、Ｒｅ（θ）は法線方向から角度θ傾斜した方向におけるレターデーション値をあらわす。また、数式（Ｂ）中のβは、屈折率楕円体が一様傾斜したことを仮定した場合の傾斜角度を表し、傾斜型位相差フィルムの構造を単純に把握するときに使用される。
上記の測定において、平均屈折率の仮定値は、ポリマーハンドブック（ＪＯＨＮ ＷＩＬＥＹ＆ＳＯＮＳ，ＩＮＣ）、各種光学補償フィルムのカタログの値を使用することができる。また、平均屈折率の値が既知でないものについては、アッベ屈折計で測定することができる。主な光学補償フィルムの平均屈折率の値を以下に例示する：セルロースアシレート（１．４８）、シクロオレフィンポリマー（１．５２）、ポリカーボネート（１．５９）、ポリメチルメタクリレート（１．４９）、ポリスチレン（１．５９）である。 Rth is calculated by calculating the refractive indices nx, ny, and nz in each direction of the refractive index ellipsoid and substituting them into the following formula (A), assuming that the refractive index ellipsoid is uniformly inclined by β °. be able to.
Rth = ((nx + ny) / 2−nz) × d Formula (A)
In the film of the present invention, ny is the refractive index in the film width direction. nx is the refractive index in the direction in which the projection component on the x-axis of the film is larger than the projection component on the z-axis, and nz is the refractive index in the direction in which the projection component on the z-axis is larger than the projection component on the x-axis.
The method for obtaining nx, ny, and nz is described in the technical data of Oji Scientific Instruments Co., Ltd. (http://www.oji-keisoku.co.jp/products/kobra/kobra.html). For example, it is possible to calculate from the values of Re [0 °], Re [+ 40 °] and Re [−40 °], the value of average refractive index n _ave , and the film thickness value d using the following formula (B). I can do it.

In the formula, Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction. In addition, β in the mathematical formula (B) represents an inclination angle when it is assumed that the refractive index ellipsoid is uniformly inclined, and is used when the structure of the inclined retardation film is simply grasped.
In the above measurement, as the assumed value of the average refractive index, the values in the polymer handbook (John Wiley & Sons, Inc.) and catalogs of various optical compensation films can be used. Moreover, about the thing whose average refractive index value is not known, it can measure with an Abbe refractometer. The average refractive index values of the main optical compensation films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49) Polystyrene (1.59).

  The Rth is an index of the difference between the refractive index (orientation) in the thickness direction (Z direction) and the plane orientation (orientation in the XY direction). The Rth is preferably 40 nm to 400 nm, more preferably 50 nm to 350 nm, and still more preferably 60 nm to 250 nm.

  A film having γ, Re [0 °] and Rth in the above preferred ranges can be produced by the production method of the present invention described later. In addition, when the optical film having the preferable optical characteristics is used for optical compensation of a liquid crystal display such as a TN mode, an ECB mode, and an OCB mode, it contributes to an improvement in viewing angle characteristics and achieves a wide viewing angle. be able to.

  Variations in Re [0 °], Re [+ 40 °], and Re [−40 °] appear as display unevenness when used in a liquid crystal display. Therefore, the variation is preferably as small as possible. It is preferably within ± 3 nm, and more preferably within ± 1 nm. Similarly, the variation in the angle of the slow axis also causes display unevenness. Therefore, the variation is preferably as small as possible, specifically within ± 1 °, preferably within ± 0.5 °. It is more preferable that the angle is within ± 0.25 °.

The optical characteristic value can be measured by the following method.
In the present invention, Re [0 °], Re [+ 40 °] and Re [−40 °] of the film are measured using KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments Co., Ltd.). , The phase difference at an inclination angle of 0 °, the phase difference at an inclination angle of 40 degrees, and the phase difference at an inclination angle of −40 degrees were measured.
Here, the inclination direction was determined by the following method.
(1) The slow axis direction in the film plane is 0 °, the fast axis direction in the film plane is 90 °, and the temporary tilt direction is set in increments of 0.1 ° between 0 ° and 90 °.
(2) Re [+ 40 °] and Re [−40 °] are measured in a plane including each provisional tilt direction and the film normal to obtain | Re [+ 40 °] −Re [−40 °] |.
(3) The direction in which | Re [+ 40 °] −Re [−40 °] | is maximized is determined as the tilt direction.
The measurement wavelength is 550 nm. Note that a film made of a general thermoplastic resin by a melt film forming method has a value of | Re [+ 40 °] −Re [−40 °] | ≈0 nm regardless of the orientation. That is, when | Re [+ 40 °] −Re [−40 °] | is measured in the tilt direction, it is a feature of the film of the present invention that a phase difference of 0 nm or more is expressed.
In addition, variations in Re [0 °], Re [+ 40 °], and Re [−40 °] can be measured by the following method. Sampling is performed at any 10 or more positions on the film surface 2 mm or more away from each other, and Re [0 °], Re [+ 40 °] and Re [−40 °] are measured by the above method. The difference in value is defined as the variation of Re [0 °], Re [+ 40 °], and Re [−40 °].
Further, the variation of the slow axis and Rth is measured in the same manner.

(Re [0 °], Rth durability)
The film of the present invention has a small change in optical properties when stored for a long time at a high temperature. Thus, by improving the durability of optical properties, high retardation can be exhibited for a long time even at high temperatures, and a film suitable for use at high temperatures can be obtained.
The absolute value ΔRe [0 °] of the change in Re [0 °] around 500 hours at 90 ° C. relative humidity of 10% of the film of the present invention is preferably 10 nm or less, more preferably 5 nm or less. Particularly preferably, it is 3 nm or less.
The absolute value ΔRth of the fluctuation of Rth before and after 500 hours at 90 ° C. relative humidity of 10% of the film of the present invention is preferably 10 nm or less, more preferably 5 nm or less, and particularly preferably 3 nm or less. preferable.

(Thickness)
The film of the present invention preferably has a thickness of 10 μm to 90 μm, more preferably 20 μm to 80 μm, and even more preferably 25 μm to 70 μm.

[Method for producing thermoplastic resin film]
The method for producing a thermoplastic resin film of the present invention (hereinafter also referred to as the production method of the present invention) comprises a step of melting and kneading a composition containing a thermoplastic resin and an additive, A step of cooling to a glass transition temperature of the plastic resin or lower to solidify, a step of melt-extruding a thermoplastic resin-containing composition containing the solidified composition from a die, and a sandwiching device for the melt-extruded melt A step of continuously pressing between the first clamping surface and the second clamping surface to form a film, the pressure applied to the melt by the clamping device is 20 MPa to 120 MPa, and the first The moving speed of one clamping surface is made faster than the moving speed of the second clamping surface. Applying such a large pressure is a feature of the present invention that is different from the conventional method. Examples of the clamping device having different speeds on the first clamping surface and the second clamping surface include, for example, a combination of two rolls having different peripheral speeds, and rolls having different speeds described in Japanese Patent Application Laid-Open No. 2000-219752. Examples include a combination of touch belts (single-sided belt method), a combination of belts and belts (double-sided belt method), and the like. Among these, since it is possible to uniformly apply a high pressure of 20 to 120 MPa, it is preferable that the two rolls have different peripheral speeds. The roll pressure can be measured by passing a pressure measurement film (such as a prescale for medium pressure by Fuji Film) through two rolls. Etc.) can be measured by passing them through two rolls. By including the method for producing the thermoplastic resin composition of the present invention, it is possible to obtain a film having good optical developability, a phase difference gradient structure, and good optical property durability. Hereinafter, the manufacturing method of the thermoplastic resin film of this invention is demonstrated.

<Melting and kneading of a composition containing a thermoplastic resin and an additive>
(Additive)
In the production method of the present invention, an additive is added when melt-kneading the thermoplastic resin. The additive functions more efficiently by being more uniformly dispersed in the thermoplastic resin. In the method for producing a thermoplastic resin composition of the present invention, the amount of the additive is preferably 0.1% by mass to 20% by mass, more preferably 0.2% by mass to 15%, and still more preferably based on the thermoplastic resin. Is 0.3 mass% to 10 mass%. If the amount of the additive is 20% by mass or less with respect to the thermoplastic resin, the additive is preferable because it can be dispersed sufficiently uniformly without being excessive, and if it is 0.1% by mass or more, uniform dispersion is achieved. It is preferable because it is easy.
In the production method of the present invention, the additive is not particularly limited. For example, components other than the thermoplastic resin contained in commercially available thermoplastic resin pellets are also included in the additive, and the additive includes a stabilizer and a plasticizer. At least one selected from inorganic fine particles, ultraviolet absorbers and optical adjusting agents is preferable.

Stabilizer:
In the present invention, a stabilizer is added to suppress thermal decomposition. However, since thermal decomposition occurs evenly throughout the thermoplastic resin, the stabilizing action is better when the stabilizer is uniformly dispersed. It is easy to express more efficiently. Therefore, when a stabilizer is added in the method for producing the thermoplastic resin composition of the present invention, the effect of inhibiting the decomposition of the thermoplastic resin can be further enhanced.

The following are mentioned as said stabilizer.
Stabilizers include coloring and molecular weight, including unresolved decomposition reactions, such as preventing oxidation of film components, capturing acid generated by decomposition, and inhibiting or prohibiting decomposition reactions caused by radical species due to light or heat. It is useful for suppressing the generation of volatile components due to alterations such as degradation and decomposition of materials. At that time, the stabilizer itself is required to function without being decomposed even at a melting temperature for film formation. These stabilizers are used for the following effects, but are not limited thereto.

  Typical stabilizers include phenolic stabilizers, phosphite stabilizers (phosphite), thioether stabilizers, amine stabilizers, epoxy stabilizers, lactone stabilizers, amine stabilizers. Agents, metal deactivators (tin-based stabilizers), and the like. These are described in JP-A-3-199201, JP-A-5-1907073, JP-A-5-194789, JP-A-5-271471, JP-A-6-107854, and the like. Then, it is preferable to use at least one or more of phenol-based and phosphorous-based stabilizers.

  These stabilizers can be used alone or in combination of two or more, and the blending amount thereof is appropriately selected within a range not impairing the object of the present invention. Preferably, the addition amount of the stabilizer is preferably 0.001% by mass to 5% by mass, more preferably 0.005% by mass to 3% by mass, and still more preferably 0.01% by mass with respect to the mass of the acrylic resin. % By mass to 0.8% by mass.

  In the present invention, a hindered phenol stabilizer useful as a compound used for stabilizing the film constituting material at the time of heat melting is a known compound, for example, U.S. Pat. No. 4,839,405. 2,6-dialkylphenol derivative compounds such as those described in columns 12-14 are included. Especially, it is a preferable aspect to add especially the phenol type stabilizer of molecular weight 500 or more. Preferable phenolic stabilizers include hindered phenolic stabilizers. These materials are readily available as commercial products and are sold by the following manufacturers. Irganox 1076, Irganox 1010, Irganox 3113, Irganox 245, Irganox 1135, Irganox 1330, Irganox 259, Irganox 565, Irganox 1025, Irganox 1035, Irganox 1035, Irganox 1035, Irganox 1035 Moreover, it can obtain from Asahi Denka Kogyo Co., Ltd. as ADK STAB AO-50, ADK STAB AO-60, ADK STAB AO-20, ADK STAB AO-70, and ADK STAB AO-80. Furthermore, from Sumitomo Chemical Co., Ltd., it can obtain as Sumilizer BP-76, Sumilizer BP-101, Sumilizer GA-80. In addition, it is also possible to obtain as Sinox 326M and Sinox 336B from Sipro Kasei Co., Ltd.

  As the phosphite stabilizer, compounds described in [0023] to [0039] of JP-A No. 2004-182979 can be more preferably used. Specific examples of the phosphite ester stabilizer include JP-A No. 51-70316, JP-A No. 10-306175, JP-A No. 57-78431, JP-A No. 54-157159, and JP-A No. 54-157159. Listed are compounds described in JP-A-55-13765. Furthermore, as other stabilizers, the materials described in detail on pages 17 to 22 of the Japan Society for Invention and Technology (Public Technical Number 2001-1745, issued on March 15, 2001, Japan Society of Invention) are preferably used. Can do.

  The phosphite ester stabilizer of the present invention is useful to have a high molecular weight in order to maintain stability at high temperature, has a molecular weight of 500 or more, more preferably a molecular weight of 550 or more, and particularly a molecular weight of 600. The above is preferable. Furthermore, at least one substituent is preferably an aromatic ester group. The phosphite ester stabilizer is preferably a triester, and is desirably free of impurities such as phosphoric acid, monoester and diester. When these impurities are present, the content is preferably 5% by mass or less, more preferably 3% by mass or less, and particularly 2% by mass or less. These include compounds described in [0023] to [0039] of JP-A No. 2004-182979, JP-A-51-70316, JP-A-10-306175, JP-A-57. The compounds described in JP-A-78431, JP-A-54-157159, and JP-A-55-13765 can also be mentioned. Preferred specific examples of the phosphite stabilizer include the following compounds, but the phosphite stabilizer that can be used in the present invention is not limited thereto.

  These are commercially available from Asahi Denka Kogyo Co., Ltd. as ADK STAB 1178, 2112, PEP-8, PEP-24G, PEP-36G, HP-10, and Sandostab P-EPQ from Clariant. Is possible. Furthermore, stabilizers having phenol and phosphite ester in the same molecule are also preferably used, and specific compounds include the following. These compounds are further described in detail in JP-A-10-273494, and examples of such compounds are shown, but the stabilizers that can be used in the present invention are not limited thereto. A typical commercial product is Sumitizer GP available from Sumitomo Chemical Co., Ltd.

  A thioether-based stabilizer that is further used as a stabilizer will be described. In the present invention, the thioether stabilizer that can be added to the acrylic resin also preferably has a molecular weight of 500 or more, and any known thioether stabilizer can be used. These are commercially available from Sumitomo Chemical Co., Ltd. as Sumilizer TPL, TPM, TPS, TDP. It is also available from Asahi Denka Kogyo Co., Ltd. as ADK STAB AO-412S.

  As the epoxy stabilizer preferably used in the present invention, a compound having an aliphatic, aromatic, alicyclic, aromatic aliphatic or heterocyclic structure and having an epoxy group as a side chain is also useful. The epoxy group is preferably bonded to the residue of the molecule by an ether or ester bond as a glycidyl group, or is an N-glycidyl derivative of a heterocyclic amine, amide or imide. These types of epoxy compounds are widely known and are readily available as commercial products. These materials are described in detail in [0096] to [0112] of JP-A-11-189706. These epoxy materials can be obtained as commercial products from ADK STAB O-130P and ADK STAB O-180A (Asahi Denka Kogyo Co., Ltd.).

  Any known tin-based stabilizer can be used as the tin-based stabilizer. Specific examples of preferable tin-based stabilizers include octyl tin maleate polymer, monostearyl tin tris (isooctyl thioglycolate), and dibutyl tin dilaurate.

  In addition, the said stabilizer is the concept containing the acid supplementary agent and light stabilizer which are mentioned later. Acid stabilizers that focus on capturing acids, light stabilizers that focus on improving the light stability of acid supplements, and other effects other than acid supplements and light stabilizers that have the various effects described above Any of the above-mentioned stabilizers having the above may be used, but among them, a phenol-based stabilizer that captures radicals is preferred.

  Among thermoplastic resins, it is preferable to contain an acid scavenger when using a thermoplastic resin such as an acrylic resin whose decomposition is accelerated by an acid at high temperatures.

  Any acid scavenger useful in the present invention can be used without limitation as long as it is a compound that reacts with an acid to inactivate the acid, but is described in US Pat. No. 4,137,201. It preferably comprises an epoxy compound as an acid scavenger. Epoxy compounds as such acid scavengers are known in the art and are derived by condensation of various polyglycol diglycidyl ethers, particularly about 8-40 moles of ethylene oxide per mole of polyglycol. Glycol, diglycidyl ethers of glycerol, metal epoxy compounds (such as those conventionally used in and with vinyl chloride polymer compositions), epoxidized ether condensation products, diphenols of bisphenol A Glycidyl ether (ie, 4,4′-dihydroxydiphenyldimethylmethane), epoxidized unsaturated fatty acid ester (especially an ester of a fatty acid having 2 to 22 carbon atoms and an alkyl of 4 to 2 carbon atoms (eg , Butyl epoxy steer Epoxidized vegetable oils and other unsaturated natural oils (sometimes these may be represented and exemplified by compositions such as epoxidized soy oil, etc.) These are called epoxidized natural glycerides or unsaturated fatty acids, which generally contain 12 to 22 carbon atoms)). Particularly preferred are the commercially available epoxy group-containing epoxide resin compounds EPON 815c and epoxidized ether oligomer condensation products.

  Furthermore, examples of acid scavengers that can be used other than the above include oxetane compounds, oxazoline compounds, organic earth salts of alkaline earth metals and acetylacetonate complexes, and paragraphs 68 to 105 of JP-A-5-194788. Is included. In addition, although an acid scavenger may be called an acid scavenger, an acid capture agent, an acid catcher, etc., in this invention, it can use without a difference by these names.

  The acid scavenger in the film forming material used in the present invention can be selected from at least one of the above, and the amount added is 0.001% by mass with respect to the mass of the acrylic resin. -5 mass% is preferable, More preferably, it is 0.005 mass%-3 mass%, More preferably, it is 0.01 mass%-2 mass%.

  Examples of light stabilizers that can be used in the present invention include hindered amine light stabilizer (HALS) compounds, which are known compounds, such as those disclosed in US Pat. No. 4,619,956. 2-11 and US Pat. No. 4,839,405, columns 3-5, 2,2,6,6-tetraalkylpiperidine compounds, or their acid addition salts or their And a complex of a metal compound. These are commercially available from Asahi Denka as ADK STAB LA-57, LA-52, LA-67, LA-62, LA-77, and TINUVIN 765, 144 from Ciba Specialty Chemicals. .

  These hindered amine light stabilizers can be used alone or in combination of two or more, and used in combination with these hindered amine light stabilizers and additives such as plasticizers, acid scavengers, and UV absorbers. Alternatively, it may be introduced into a part of the molecular structure of the additive. The blending amount is appropriately selected within a range not impairing the object of the present invention, but is preferably 0.01 to 20 parts by mass, more preferably 0.02 to 15 parts with respect to 100 parts by mass of the polymer according to the present invention. Part by mass, particularly preferably 0.05 to 10 parts by mass. These may be added at any stage of the melt (melt) production process, and a process of adding an additive may be added at the end of the melt production process (melt preparation process).

UV absorber:
In the present invention, one or more ultraviolet absorbers may be used. From the viewpoint of preventing deterioration, the ultraviolet absorbent is preferably excellent in the ability to absorb ultraviolet light having a wavelength of 380 nm or less and has little absorption of visible light having a wavelength of 400 nm or more from the viewpoint of transparency. Examples include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. Particularly preferred ultraviolet absorbers are benzotriazole compounds and benzophenone compounds. Among these, a benzotriazole-based compound is preferable because unnecessary coloring with respect to the cellulose mixed ester is small. These are disclosed in JP-A-60-235852, JP-A-3-199201, 5-1907073, 5-194789, 5-271471, 6-107854, 6-118233, 6 -148430, 7-11056, 7-11055, 7-11056, 8-29619, 8-239509, and JP-A-2000-204173.
The following commercially available products can also be used as these ultraviolet absorbers. As benzotriazoles, TINUBIN P (Ciba Specialty Chemicals), TINUBIN 234 (Ciba Specialty Chemicals), TINUBIN 320 (Ciba Specialty Chemicals), TINUBIN 326 (Ciba Specialty Chemicals) TINUBIN 327 (Ciba Specialty Chemicals), TINUBIN 328 (Ciba Specialty Chemicals), Sumisorb 340 (Sumitomo Chemical), ADK STAB LA-31 (Asahi Denka Kogyo Co., Ltd.), etc. . In addition, as benzophenone-based ultraviolet absorbers, Seasorb 100 (manufactured by Sipro Kasei Co., Ltd.), Seasorb 101 (manufactured by Sipro Kasei Co., Ltd.), Seasorb 101S (manufactured by Sipro Kasei Co., Ltd.), Seasorb 102 (manufactured by Sipro Kasei Co., Ltd.), Seasorb 103 (Sipro Kasei) Kasei Co., Ltd.), Adeka Stub LA-51 (Asahi Denka Kogyo Co., Ltd.), Chemisorp 111 (Kemipro Kasei Co., Ltd.), UVINUL D-49 (BASF Corp.), and the like. Examples of oxalic acid anilide UV absorbers include TINUBIN 312 (manufactured by Ciba Specialty Chemicals) and TINUBIN 315 (manufactured by Ciba Specialty Chemicals). In addition, as a salicylic acid ultraviolet absorber, Seasorb 201 (manufactured by Sipro Kasei) and Seasorb 202 (manufactured by Sipro Kasei) are marketed, and as a cyanoacrylate ultraviolet absorber, Seasorb 501 (manufactured by Sipro Kasei), UVINUL N-539 (BASF) is available. Among these, ADK STAB LA-31 is particularly preferable.
The addition amount of the ultraviolet absorber is preferably 0.01 to 2% by mass of the thermoplastic resin, and more preferably 0.01 to 1.5% by mass.

Plasticizer:
In the present invention, it is preferable to add at least one plasticizer in the film forming material.
The plasticizer is added to increase the fluidity of the thermoplastic resin molecules. However, if a dispersion failure occurs, the fluidity of the poorly dispersed portion decreases during kneading and melting, and is susceptible to shearing, from which the molecules are cut and decomposed. It is not preferable because it tends to generate a product. In addition, when a plasticizer is added, the melting temperature of the thermoplastic resin composition can be lowered, and the effect of suppressing the thermal decomposition of the thermoplastic resin composition can be enhanced.

  Generally, a plasticizer is an additive having an effect of improving brittleness or imparting flexibility by adding it to a polymer, but in the present invention, a thermoplastic resin alone is used. It is preferable to add a plasticizer in order to lower the melting temperature than the melting temperature, and to lower the melt viscosity of the film-constituting material containing the plasticizer than the thermoplastic resin alone at the same heating temperature. Moreover, since it adds also in order to improve the hydrophilic property of a thermoplastic resin and to improve the water vapor transmission rate of a thermoplastic resin film, it has a function as a moisture permeation preventive agent.

  Here, the melting temperature of the film constituting material means a temperature at which the material is heated and fluidity is developed. In order to melt and flow the thermoplastic resin, it is necessary to heat at least a temperature higher than the glass transition temperature. Above the glass transition temperature, the elastic modulus or viscosity decreases due to heat absorption, and fluidity is exhibited. However, in thermoplastic resins, the molecular weight of the thermoplastic resin may decrease due to thermal decomposition at the same time as melting at high temperatures, which may adversely affect the mechanical properties of the resulting film. Therefore, melt the thermoplastic resin at the lowest possible temperature. It is necessary to let In order to lower the melting temperature of the film constituting material, it can be achieved by adding a plasticizer having a melting point or glass transition temperature lower than the glass transition temperature of the thermoplastic resin.

The plasticizer may be a liquid or a solid, and is preferably colorless due to restrictions on the composition. Thermally, it is preferably stable at higher temperatures, and the decomposition start temperature is preferably 150 ° C. or higher, more preferably 200 ° C. or higher. The addition amount may be as long as optical properties and mechanical properties are not adversely affected, and the blending amount is appropriately selected within a range that does not impair the object of the present invention, and is preferably set to 0.1 parts by weight with respect to 100 parts by mass of the thermoplastic resin according to the present invention. It is 1-30 mass parts, More preferably, it is 0.5-25 mass parts. 1-20 mass% is especially preferable. If the amount is less than 0.1% by mass, the effect of improving the flatness is not recognized. If the amount is more than 30% by mass, bleeding out tends to occur and the temporal stability of the film decreases, which is not preferable.
As the plasticizer used in the present invention, for example, phosphate ester derivatives, carboxylic acid ester derivatives, polyvalent ester compounds having a structure in which alcohol is condensed, and polymer plasticizers are preferably used. Further, a polymer obtained by polymerizing an ethylenically unsaturated monomer having a weight average molecular weight of 500 to 10,000 described in JP-A No. 2003-12859, an acrylic polymer, an acrylic polymer having an aromatic ring in the side chain, or cyclohexyl An acrylic polymer having a group in the side chain is also preferably used.

  Hereinafter, although the specific example is given about the plasticizer used for this invention, it is not limited to these.

  Specific examples of the phosphate ester plasticizer include phosphoric acid cycloalkyl ester and phosphoric acid aryl ester. These substituents may be the same or different, and may be further substituted. Further, it may be a mix of an alkyl group, a cycloalkyl group, and an aryl group, and the substituents may be covalently bonded. Also alkylene bis (dialkyl phosphate) such as ethylene bis (dimethyl phosphate), butylene bis (diethyl phosphate), alkylene bis (diaryl phosphate) such as ethylene bis (diphenyl phosphate), propylene bis (dinaphthyl phosphate), phenylene bis (dibutyl phosphate) ), Arylene bis (dialkyl phosphate) such as biphenylene bis (dioctyl phosphate), phosphate esters such as arylene bis (diaryl phosphate) such as phenylene bis (diphenyl phosphate) and naphthylene bis (ditoluyl phosphate). These substituents may be the same or different, and may be further substituted. Further, it may be a mix of an alkyl group, a cycloalkyl group, and an aryl group, and the substituents may be covalently bonded.

  Furthermore, the phosphate ester partial structure may be part of the polymer or regularly pendant, and may be introduced into part of the molecular structure of additives such as antioxidants, acid scavengers, and UV absorbers. May be. Among the above-mentioned compounds, phosphoric acid aryl ester and arylene bis (diaryl phosphate) are preferable, and specifically, triphenyl phosphate and phenylene bis (diphenyl phosphate) are preferable. Moreover, it is also preferable to use the phosphate ester type plasticizer described in claims 3 to 7 of JP-T-6-501040. Further, as the phosphoric ester plasticizer, [0027] to [0034] of JP-A No. 2002-363423, [0027] to [0034] of JP-A No. 2002-265800, JP-A No. 2003-155292 Examples of preferable phosphoric acid ester compounds described in [0014] to [0040] are:

  Specific examples of the phosphate ester plasticizer are listed below, but the phosphate ester plasticizer that can be used in the present invention is not limited thereto. These compounds are commercially available from Asahi Denka Kogyo Co., Ltd. as ADK STAB FP-500, ADK STAB FP-600, ADK STAB FP-700, ADK STAB FP-2100, ADK STAB PFR, and the like. It can also be obtained from Ajinomoto Chemical Co., Ltd. as Leoforce BAPP.

  Examples of carboxylic acid esters include polyhydric alcohols such as phthalic acid esters, citric acid esters, adipic acid esters, aromatic polycarboxylic acid esters, aliphatic polycarboxylic acid esters, and diglycerin tetraacetate. And fatty acid esters. In addition, butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, etc. are preferably used alone or in combination.

In the present invention, the saccharide plasticizer is preferably a monosaccharide or a derivative of a carbohydrate containing 2 to 10 monosaccharide units. These monosaccharides or polysaccharides may be substituted with groups (for example, A hydroxyl group, a carboxyl group, an amino group, a mercapto group, and the like). Examples of the substituent include an ether group, an ester group, an amide group, and an imide group.
Examples of monosaccharides or carbohydrates containing 2-10 monosaccharide units include, for example, erythrose, threose, ribose, arabinose, xylose, lyxose, allose, altrose, glucose, fructose, mannose, gulose, idose, galactose, Tulose, trehalose, isotrehalose, neotrehalose, trehalosamine, kojibiose, nigerose, maltose, maltitol, isomaltose, sophorose, laminaribiose, cellobiose, α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, δ-cyclo Examples include dextrin, xylitol, sorbitol, and the like.

  Polymer plasticizers are also preferably used, specifically, aliphatic hydrocarbon polymers, alicyclic hydrocarbon polymers, acrylic polymers such as polyethyl acrylate and polymethyl methacrylate, polyvinyl isobutyl ether, poly N-vinyl. Vinyl polymers such as pyrrolidone, styrene polymers such as polystyrene and poly 4-hydroxystyrene, polybutylene succinate, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyethers such as polyethylene oxide and polypropylene oxide, polyamides, polyurethanes and polyureas Etc. The number average molecular weight is preferably about 1,000 to 500,000, particularly preferably 5,000 to 200,000. If it is 1,000 or less, a problem arises in volatility, and if it exceeds 500,000, the plasticizing ability is lowered, which adversely affects the mechanical properties of the thermoplastic resin. These polymer plasticizers may be a homopolymer composed of one type of repeating unit or a copolymer having a plurality of repeating structures. Two or more of the above polymers may be used in combination, and other plasticizers, antioxidants, acid scavengers, ultraviolet absorbers, slip agents, matting agents, and the like may be included.

  As the plasticizer used in the present invention, an ester compound having a structure in which an organic acid represented by the following general formula (1) and a trivalent or higher alcohol are condensed is preferably used.

In the formula, R ^{1 to} R ⁵ represent a hydrogen atom or a cycloalkyl group, an aralkyl group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an aralkyloxy group, an acyl group, a carbonyloxy group, an oxycarbonyl group, or an oxycarbonyloxy group. These may be further substituted. L represents a linking group and represents a substituted or unsubstituted alkylene group, an oxygen atom, or a direct bond.

The cycloalkyl group represented by R ^{1 to} R ⁵ is preferably a cycloalkyl group having 3 to 8 carbon atoms, and specifically, a group such as cyclopropyl, cyclopentyl, cyclohexyl and the like. These groups may be substituted, and preferred substituents include halogen atoms such as chlorine atom, bromine atom, fluorine atom, hydroxyl group, alkyl group, alkoxy group, cycloalkoxy group, aralkyl group (this phenyl group). The group may be further substituted with an alkyl group or a halogen atom), an alkenyl group such as a vinyl group or an allyl group, or a phenyl group (this phenyl group may be further substituted with an alkyl group or a halogen atom). Phenoxy group (this phenyl group may be further substituted by an alkyl group or a halogen atom), an acyl group having 2 to 8 carbon atoms such as an acetyl group or a propionyl group, an acetyloxy group, or a propionyloxy group. And an unsubstituted carbonyloxy group having 2 to 8 carbon atoms such as a group.

The aralkyl group represented by R ^{1 to} R ⁵ represents a group such as a benzyl group, a phenethyl group, and a γ-phenylpropyl group, and these groups may be substituted. Preferred substituents include The group which may be substituted with the said cycloalkyl group can be mentioned similarly.

Examples of the alkoxy group represented by R ^{1 to} R ⁵ include an alkoxy group having 1 to 8 carbon atoms, specifically, methoxy, ethoxy, n-propoxy, n-butoxy, n-octyloxy, isopropoxy. , Alkoxy groups such as isobutoxy, 2-ethylhexyloxy, and tert-butoxy. These groups may be substituted, and preferred substituents include halogen atoms such as chlorine atom, bromine atom, fluorine atom, hydroxyl group, alkoxy group, cycloalkoxy group, aralkyl group (this phenyl group). May be substituted with an alkyl group or a halogen atom), an alkenyl group, a phenyl group (this phenyl group may be further substituted with an alkyl group or a halogen atom), an aryloxy group (for example, phenoxy) An acyl group such as an acetyl group or a propionyl group, or an aryl group such as an acetyloxy group or a propionyloxy group (the phenyl group may be further substituted with an alkyl group or a halogen atom). Arylcarbonyl groups such as unsubstituted acyloxy groups and benzoyloxy groups Shi group.

Examples of the cycloalkoxy group represented by R ^{1 to} R ⁵ include an unsubstituted cycloalkoxy group having 1 to 8 carbon atoms, specifically, cyclopropyloxy, cyclopentyloxy, cyclohexyl. And groups such as oxy. In addition, these groups may be substituted, and preferred substituents include the same groups that may be substituted with the cycloalkyl group.

Examples of the aryloxy group represented by R ^{1 to} R ⁵ include a phenoxy group, and the phenyl group includes a substituent that is exemplified as a group that may be substituted with the cycloalkyl group such as an alkyl group or a halogen atom. May be substituted.

Examples of the aralkyloxy group represented by R ^{1 to} R ⁵ include a benzyloxy group, a phenethyloxy group, and the like. These substituents may be further substituted. Preferred substituents include the above-mentioned cycloalkyl. The group which may be substituted with a group can be mentioned similarly.

Examples of the acyl group represented by R ^{1 to} R ⁵ include an unsubstituted acyl group having 2 to 8 carbon atoms such as an acetyl group and a propionyl group (the hydrocarbon group of the acyl group includes alkyl, alkenyl, alkynyl). These substituents may be further substituted, and preferred substituents include the same groups that may be substituted with the cycloalkyl group.

The carbonyloxy group represented by R ^{1 to} R ⁵ is an unsubstituted acyloxy group having 2 to 8 carbon atoms such as acetyloxy group and propionyloxy group (the hydrocarbon group of the acyl group is alkyl, alkenyl, alkynyl). And arylcarbonyloxy groups such as a benzoyloxy group, and these groups may be further substituted with the same groups as those which may be substituted with the cycloalkyl group.

The oxycarbonyl group represented by R ^{1 to} R ⁵ represents an alkoxycarbonyl group such as a methoxycarbonyl group, an ethoxycarbonyl group or a propyloxycarbonyl group, or an aryloxycarbonyl group such as a phenoxycarbonyl group. These substituents may be further substituted, and preferred examples of the substituent include the same groups that may be substituted with the cycloalkyl group.

The oxycarbonyloxy group represented by R ^{1 to} R ⁵ represents a C 1-8 alkoxycarbonyloxy group such as a methoxycarbonyloxy group, and these substituents may be further substituted. Preferable substituents include the same groups that may be substituted on the cycloalkyl group.

Any one of R ^{1 to} R ⁵ may be connected to each other to form a ring structure.

The linking group represented by L represents a substituted or unsubstituted alkylene group, an oxygen atom, or a direct bond, and the alkylene group is a group such as a methylene group, an ethylene group, or a propylene group. These groups may be further substituted with the groups mentioned as the groups that may be substituted with the groups represented by R ^{1 to} R ⁵ .

  Among these, a direct bond and an aromatic carboxylic acid are particularly preferable as the linking group represented by L.

In addition, the organic acid represented by the general formula (1) constituting the ester compound serving as a plasticizer in the present invention includes at least R ¹ or R ² having the alkoxy group, acyl group, oxycarbonyl group, carbonyl group. Those having an oxy group or an oxycarbonyloxy group are preferred. A compound having a plurality of substituents is also preferred. In addition, the organic acid which substitutes the hydroxyl group of trihydric or more alcohol may be single type, or may be multiple types.

  The trivalent or higher alcohol compound that reacts with the organic acid represented by the general formula (1) to form a polyhydric alcohol ester compound is preferably a 3-20 valent aliphatic polyhydric alcohol. As for the above alcohol, what is represented by following General formula (3) is preferable.

  General formula (3) R '-(OH) m In the formula, R' represents an m-valent organic group, m represents a positive integer of 3 or more, and the OH group represents an alcoholic hydroxyl group. Particularly preferred is a polyhydric alcohol having 3 or 4 as m.

  Examples of preferred polyhydric alcohols include the following, but the present invention is not limited to these. Adonitol, arabitol, 1,2,4-butanetriol, 1,2,3-hexanetriol, 1,2,6-hexanetriol, glycerin, diglycerin, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, ga Examples include lactitol, glucose, cellobiose, inositol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, and xylitol. In particular, glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol are preferable.

  The ester of the organic acid represented by the general formula (1) and a trihydric or higher polyhydric alcohol can be synthesized by a known method. In the examples, typical synthesis examples are shown. A method of condensing an organic acid represented by the general formula (1) and a polyhydric alcohol in the presence of an acid, for example, There are a method of reacting with a polyhydric alcohol by leaving it as a chloride or an acid anhydride, a method of reacting a phenyl ester of an organic acid with a polyhydric alcohol, etc., and a method with a good yield is appropriately selected according to the target ester compound. It is preferable.

  As the plasticizer comprising an organic acid represented by the general formula (1) and an ester of a trihydric or higher polyhydric alcohol, a compound represented by the following general formula (2) is preferable.

In the formula, R ^{6 to} R ²⁰ represent a hydrogen atom or a cycloalkyl group, an aralkyl group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an aralkyloxy group, an acyl group, a carbonyloxy group, an oxycarbonyl group, or an oxycarbonyloxy group. These may be further substituted. R ²¹ represents a hydrogen atom or an alkyl group.

The cycloalkyl group, aralkyl group, alkoxy group, cycloalkoxy group, aryloxy group, aralkyloxy group, acyl group, carbonyloxy group, oxycarbonyl group, and oxycarbonyloxy group represented by the above R ^{6 to} R ²⁰ The same group as R < ¹ > -R < ⁵ > of (1) is mentioned.

  Although there is no restriction | limiting in particular in the molecular weight of the polyhydric alcohol ester obtained in this way, it is preferable that it is 300-1500, and it is further more preferable that it is 400-1000. A higher molecular weight is preferred because it is less likely to volatilize, and a smaller one is preferred in terms of moisture permeability and compatibility with thermoplastic resins.

Fine particles:
In the present invention, fine particles may be mixed in the thermoplastic resin. Examples of the fine particles include fine particles of inorganic compounds and fine particles of organic compounds, and any of them may be used. The average primary particle size of the fine particles contained in the thermoplastic resin in the present invention is preferably 5 nm to 3 μm, more preferably 5 nm to 2.5 μm, more preferably 10 nm to 2.0 μm from the viewpoint of keeping haze low. More preferably. Here, the average primary particle size of the fine particles is determined by observing the thermoplastic resin film with a transmission electron microscope (magnification of 500,000 to 1,000,000 times) and determining the average value of the primary particle sizes of 100 particles. The addition amount of the fine particles is preferably 0.005 to 1.0% by mass with respect to the thermoplastic resin, more preferably 0.01 to 0.8% by mass, and further preferably 0.02 to 0%. 4% by mass.

The average secondary particle size of the fine particles in the thermoplastic resin film finally obtained by the production method of the present invention is preferably 0.01 to 5 μm, more preferably 0.02 to 3 μm. It is preferably 0.02 to 1 μm. Here, the average secondary particle size of the fine particles is obtained by observing the thermoplastic resin film with a transmission electron microscope (magnification: 100,000 to 1,000,000 times) and calculating the average value of the secondary particle sizes of 100 particles. decide. Examples of the inorganic _{compound, SiO 2, ZnO, TiO 2} , SnO 2, Al 2 O 3, ZrO 2, In 2 O 3, MgO, BaO, MoO 2, V 2 O 5, talc, clay, calcined kaolin, calcined Examples include calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, and calcium phosphate. Preferably, it is at least one of SiO ₂ , ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , ZrO ₂ , In ₂ O ₃ , MgO, BaO, MoO ₂ and V ₂ O ₅ , more preferably SiO _2. , TiO ₂ , SnO ₂ , Al ₂ O ₃ and ZrO ₂ .

As the SiO ₂ fine particles, for example, commercially available products such as Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (above, Nippon Aerosil Co., Ltd.) can be used. . As the ZrO ₂ fine particles, for example, commercially available products such as Aerosil R976 and R811 (above, manufactured by Nippon Aerosil Co., Ltd.) can be used. Seahoster KE-E10, E30, E40, E50, E70, E70, E150, W10, W30, W50, P10, P30, P50, P100, P150, P250 ) Etc. can also be used. Furthermore, silica micro beads P-400 and 700 (catalyst chemical industry product) can also be used. Also, SO-G1, SO-G2, SO-G3, SO-G4, SO-G5, SO-G6, SO-E1, SO-E2, SO-E3, SO-E4, SO-E5, SO-E6, SO-C1, SO-C2, SO-C3, SO-C4, SO-C5, SO-C6 (manufactured by Admatechs Co., Ltd.) can also be used. Further, silica particles 8050, 8070, 8100, and 8150 (manufactured by Moritex Co., Ltd., powdered water dispersion) can also be used.

Optical adjusting agent:
An optical adjusting agent can be added to the thermoplastic resin in the present invention. Examples of the optical adjusting agent include a retardation adjusting agent, for example, those described in JP-A Nos. 2001-166144, 2003-344655, 2003-248117, and 2003-66230. Can be used. By adding an optical adjusting agent, in-plane retardation (Re) and thickness direction retardation (Rth) can be controlled. A preferable addition amount is 0 to 10% by mass, more preferably 0 to 8% by mass, and further preferably 0 to 6% by mass.

(Thermoplastic resin)
There is no restriction | limiting in particular as a thermoplastic resin used with the manufacturing method of this invention, A well-known thermoplastic resin and a commercially available thermoplastic resin pellet can be used, and it is in a thermoplastic resin composition by the manufacturing method of this invention. The effect of reducing the volatilization component is obtained. In particular, the effect of the present invention can be remarkably obtained when unreacted monomers and additives in the thermoplastic resin are contained, such as when commercially available thermoplastic resin pellets are used.

  When the thermoplastic resin used in the present invention is produced by using a melt extrusion method, it is preferable to use a material having good melt extrusion moldability. From this viewpoint, a cyclic olefin resin, a cellulose acylate type is used. Resins, polycarbonate resins, polyesters, polyolefins such as transparent polyethylene, transparent polypropylene, polyarylates, polysulfones, polyethersulfones, maleimide copolymers, transparent nylons, transparent fluororesins, transparent phenoxys It is preferable to select polyetherimides, polystyrenes, acrylic resins, and styrene resins. One kind of the resin may be contained, or two or more kinds of the resins different from each other may be contained. The film of the present invention preferably contains at least one of a cyclic olefin resin, a cellulose acylate resin, a polycarbonate resin, a styrene resin, and an acrylic resin. The cyclic olefin resin, the cellulose acylate resin, and the polycarbonate It is more preferable that at least one of a resin and an acrylic resin is included. The cyclic olefins are preferably cyclic olefins obtained by addition polymerization.

In particular, when a cellulose acylate resin, a cyclic olefin resin, and a polycarbonate resin exhibiting positive intrinsic birefringence are subjected to shear deformation with two rolls, the slow axis faces the tilt direction, and | Re [ + 40 °] −Re [−40 °] |> 0 film can be produced. For example, when two rolls are arranged in parallel to the die exit, the tilt direction is the same as the film longitudinal direction.
Also, acrylic resin and styrene resin exhibiting negative intrinsic birefringence, when the above processing is performed, the fast axis is directed to the tilt direction, and | Re [+ 40 °] −Re [−40 °] | > 0 films can be created.

  When the film of the present invention is applied to a liquid crystal display device as a viewing angle compensation film, the positive or negative intrinsic birefringent resin is appropriately used in consideration of the characteristics of the liquid crystal display device and the convenience of polarizing plate processing. You can select and use.

Examples of the cyclic olefin resin that can be used in the present invention include a norbornene resin obtained by polymerization of a norbornene compound. Further, it may be a resin obtained by any polymerization method of ring-opening polymerization and addition polymerization.
Examples of the addition polymerization and the cyclic olefin-based resin obtained thereby include, for example, Japanese Patent No. 3517471, Japanese Patent No. 3559360, Japanese Patent No. 3867178, Japanese Patent No. 3871721, Japanese Patent No. 3907908, Japanese Patent No. 3945598, Special Table 2005 Nos. 527696, 2006-28993, 2006-11361, WO 2006/004376, and WO 2006/0307077. . Among these, those described in Japanese Patent No. 3517471 are particularly preferable.
Examples of the ring-opening polymerization and the cyclic olefin-based resin obtained thereby include International Publication WO 98/98499 pamphlet, Japanese Patent No. 30605532, Japanese Patent No. 3320478, Japanese Patent No. 3273046, Japanese Patent No. 3404027, Japanese Patent No. 3428176. , Japanese Patent No. 3687231, Japanese Patent No. 3873934, and Japanese Patent No. 3912159. Among these, those described in International Publication WO 98/14499 pamphlet and Japanese Patent No. 30605532 are particularly preferable.
Among these cyclic olefin-based resins, those obtained by addition polymerization are preferable from the viewpoint of the expression of birefringence and the melt viscosity. For example, “TOPAS # 6013” (manufactured by Polyplastics) can be used.

  Examples of the cellulose acylate resin that can be used in the present invention include any cellulose acylate in which three hydroxyl groups in a cellulose unit are at least partially substituted with an acyl group. The acyl group (preferably an acyl group having 3 to 22 carbon atoms) may be either an aliphatic acyl group or an aromatic acyl group. Among them, cellulose acylate having an aliphatic acyl group is preferable, those having an aliphatic acyl group having 3 to 7 carbon atoms are more preferable, those having an aliphatic acyl group having 3 to 6 carbon atoms are more preferable, and carbon number More preferably has 3 to 5 aliphatic acyl groups. A plurality of these acyl groups may be present in one molecule. Examples of preferred acyl groups include acetyl, propionyl, butyryl, pentanoyl, hexanoyl and the like. Among these, a cellulose acylate having one or more selected from an acetyl group, a propionyl group and a butyryl group is more preferable, and an even more preferable one has both an acetyl group and a propionyl group. Cellulose acylate (CAP). The CAP is preferable in terms of easy resin synthesis and high stability of extrusion molding.

  As the cellulose acylate, for example, those described in JP-A-2001-188128, JP-A-2006-142800, and JP-A-2007-98917 can be used, and the total acyl substitution degree is preferably 2.1 to 3.0. The substitution degree of the group is preferably 0.05 to 2.5, more preferably 0.05 to 0.5 or 1.5 to 2.5. The degree of propionyl substitution is preferably 0.1 to 2.8, more preferably 0.1 to 1.2 or 2.3 to 2.8. Such a cellulose acylate has a low melting temperature and improved meltability, and therefore has excellent melt extrusion film forming properties.

  There is no restriction | limiting in particular about the mass average polymerization degree and number average molecular weight of a cellulose acylate-type resin. In general, the mass average degree of polymerization is about 350 to 800, and the number average molecular weight is about 70000 to 230,000. The cellulose acylate resin can be synthesized using an acid anhydride or acid chloride as an acylating agent. In the industrially most general synthesis method, cellulose obtained from cotton linter, wood pulp, etc. is converted into organic acids (acetic acid, propionic acid, butyric acid) corresponding to acetyl groups and other acyl groups, or their acid anhydrides (anhydrous anhydride). A cellulose ester is synthesized by esterification with a mixed organic acid component containing acetic acid, propionic anhydride, and butyric anhydride). As a method for synthesizing cellulose acylate satisfying the above formulas (S-1) and (S-2), the technical report of the Japan Society of Invention (Public Technical Number 2001-1745, published on March 15, 2001, Japan Society of Invention) 7 Pp. 12 to 12, JP-A-2006-45500, JP-A-2006-241433, JP-A-2007-138141, JP-A-2001-188128, JP-A-2006-142800, JP-A-2007. Reference can be made to the method described in Japanese Patent No. 98917.

  Examples of polycarbonate resins that can be used in the present invention include polycarbonate resins having a bisphenol A skeleton, which are obtained by reacting a dihydroxy component and a carbonate precursor by an interfacial polymerization method or a melt polymerization method. JP-A-2006-277914, JP-A-2006-106386, and JP-A-2006-284703 can be preferably used. For example, “Taflon MD1500” (manufactured by Idemitsu Kosan Co., Ltd.) can be used as a commercial product.

The styrenic resin that can be used in the present invention refers to a resin obtained by polymerizing styrene and derivatives thereof as a main component, and copolymers of other resins, and is not particularly limited as long as the effects of the present invention are not impaired. A known styrene-based thermoplastic resin can be used, and a copolymer resin that can improve birefringence, film strength, and heat resistance is particularly preferable.
Examples of the copolymer resin include styrene-acrylonitrile resins, styrene-acrylic resins, styrene-maleic anhydride resins, and multi-component (binary, ternary, etc.) copolymer polymers thereof. Among these, styrene-acrylic resins and styrene-maleic anhydride resins are preferable from the viewpoints of heat resistance and film strength.
In the styrene-maleic anhydride resin, the mass composition ratio of styrene and maleic anhydride is preferably styrene: maleic anhydride = 95: 5 to 50:50, and styrene: maleic anhydride = 90: 10. More preferably, it is ˜70: 30. In order to adjust the intrinsic birefringence, hydrogenation of a styrene resin can be preferably used.
Examples of the styrene-maleic anhydride resin include “Daylark D332” manufactured by Nova Chemical Co., Ltd.
As the styrene-acrylic resin, “Delpet 980N” manufactured by Asahi Kasei Chemical Co., Ltd., which will be described later, can be used.

The acrylic resin that can be used in the present invention refers to a resin obtained by polymerizing acrylic acid, methacrylic acid and derivatives thereof as main components, and further derivatives thereof, as long as the effects of the present invention are not impaired. It does not specifically limit, A well-known methacrylic acid type thermoplastic resin etc. can be used.
Examples of the resin obtained by polymerizing acrylic acid, methacrylic acid and derivatives thereof include those having a structure represented by the following general formula (3).

前記一般式（３）中、Ｒ³¹およびＲ³²は、それぞれ独立に、水素原子または炭素数１〜２０の有機残基を示す。有機残基とは、具体的には、炭素数１〜２０の直鎖状、分枝鎖状、もしくは環状のアルキル基を示す。

In the general formula (3), R ³¹ and R ³² each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue specifically represents a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms.

Specific examples of resins obtained by polymerizing the acrylic acid, methacrylic acid and derivatives thereof include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic. N-butyl acid, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxy (meth) acrylate Propyl, 2,3,4,5,6-pentahydroxyexyl (meth) acrylate and 2,3,4,5-tetrahydroxypentyl (meth) acrylate are preferred, and in terms of excellent thermal stability (meta ) Methyl acrylate (hereinafter also referred to as MMA) is more preferable. Among these, only 1 type may be used and 2 or more types may be used together. Further, among these, it may be a single polymer, a copolymer of two or more, or a copolymer of other resins, but from the viewpoint of increasing the glass transition temperature, Particularly preferred is a copolymer with a resin.
Among the acrylic copolymer resins, those containing 30 mol% or more of MMA units (monomer) in all monomers constituting the resin are preferable. In addition to MMA, lactone ring units, maleic anhydride units, glutaric anhydrides More preferably, at least one unit of units is included, and for example, the following can be used.

(1) Acrylic resin containing a lactone ring unit JP 2007-297615 A, JP 2007-63541 A, JP 2007-70607 A, JP 2007-100044 A, JP 2007-254726 A, JP 2007-254727 A , JP 2007-261265, JP 2007-293272, JP 2007-297619, JP 2007-316366, JP 2008-9378, and JP 2008-76764. Can be used. Among these, the resin described in JP-A-2008-9378 is more preferable.
(2) Acrylic resin containing maleic anhydride unit JP 2007-113109 A, JP 2003-292714 A, JP 6-279546 A, JP 2007-51233 A (described here), JP JP-A-2001-270905, JP-A-2002-167694, JP-A-2000-302988, JP-A-2007-111110, JP-A-2007-11565 can be used. Among these, the one described in JP 2007-113109 A is more preferable. A commercially available maleic acid-modified MAS resin (for example, Delpet 980N manufactured by Asahi Kasei Chemicals Corporation) can also be preferably used.
(3) Acrylic resin containing glutaric anhydride unit JP-A-2006-241263, JP-A-2004-70290, JP-A-2004-70296, JP-A-2004-126546, JP-A-2004-163924, JP-A-2004 -291302, JP-A-2004-292812, JP-A-2005-314534, JP-A-2005-326613, JP-A-2005-331728, JP-A-2006-131898, JP-A-2006-134882, JP-A-2006- 206881, JP 2006-241197, JP 2006-283013, JP 2007-118266, JP 2007-176982, JP 2007-178504, JP 2007-197703, JP 2008-74918. No., International Publication WO2005 / 105 Those described in each publication such as 918 can be used. Among these, those described in JP-A-2008-74918 are more preferable.
The glass transition temperature (Tg) of these resins is preferably 106 ° C to 170 ° C, more preferably 110 ° C to 160 ° C, still more preferably 115 ° C to 150 ° C.

Among these, the thermoplastic resin is preferably a cyclic olefin resin, more preferably a norbornene resin from the viewpoint of high transparency, birefringence and heat resistance, and an addition polymerization type norbornene. It is particularly preferable that the resin is a series resin.
In addition, when the thermoplastic resin is a copolymer, it may be a random copolymer or a block copolymer.

(Composition comprising the thermoplastic resin and additives)
In the manufacturing method of this invention, it is preferable that it is a pellet from a viewpoint of the handleability of the composition containing the said thermoplastic resin and an additive, and film forming aptitude.

(Melt kneading)
The production method of the present invention is characterized by pre-melting and kneading a composition containing a thermoplastic resin and an additive. At this time, if the kneading is strong, the thermoplastic resin is further decomposed. Therefore, it is preferable to use an extruder having a low kneading screw.

  Therefore, it is preferable that the pellet used for melt film formation is once melted to remove unstable parts, and then pelletized again and used for melt film formation.

  In such a method for producing a thermoplastic resin composition of the present invention, the extruder is not particularly limited, but it is preferable to use a twin-screw extruder having two screws on which kneading disks are installed. In addition, since the biaxial kneader can be exhausted during the kneading, the volatile matter derived from the unstable part in the thermoplastic resin can be exhausted and removed.

  The shape of the screw included in the multi-screw extruder used in the present invention is preferably the following configuration, but is not limited to this, and may be a combination of other general configurations as long as it does not contradict the gist of the present invention.

The screw rotation type is not particularly limited, and any of the commonly used same-direction rotation type and different-direction rotation type may be applied. However, if the shear stress applied to the resin inside the screw is too high, a gel is formed. Therefore, it is preferable to select a condition with small shear stress and a screw shape. In particular, the portion having the largest shear stress inside the screw is the meshing portion, but it is particularly preferable to use a counter-rotating screw in which the shear rate of the meshing portion is zero.
As for the meshing of the screw, any of general meshing type, non-meshing type, and partial meshing type may be used. In particular, in order to avoid the formation of a deteriorated product due to resin adhesion to the screw, It is preferable to use a meshing screw having a high self-cleaning effect.

The dimensions of the screw are not particularly limited, and the screw diameter Ds is not particularly limited. However, from the viewpoint of manufacturing technology and cost, it is preferably Ds <500 mm, more preferably 30 mm <Ds <450 mm. The ratio L / Ds between the screw diameter Ds and the screw length L is preferably 10 <L / Ds <120, more preferably 15 <L / Ds <60.
As for the shape of the screw, you may use a compression type screw whose groove depth becomes shallower at the tip for deaeration and full extrusion, but gel formation by resin shearing at the compression part, resin degradation products and volatilization components Because of the possibility of occurrence, it is usually preferable to install a vacuum pump or gear pump downstream of the non-compression type full flight screw to perform deaeration and full and stable extrusion. In addition, it is preferable that the screw is a segment type rather than a single connecting structure because it is easy to change to an arbitrary screw dimension.

  As for the screw of the extrusion kneader, the segmented screw elements can be appropriately combined. Typical screw elements include a screw segment mainly for conveying materials, a kneading disk segment with enhanced dispersion mixing, and a rotor segment. The kneading disc segment imparts strong shearing to the kneaded material between the disc and the inner surface of the barrel to advance the melting, dispersion and distribution of the polymer, but at the same time generates heat due to shearing. Similarly to the kneading disk segment, the rotor segment can impart a shearing force to the kneaded material to advance kneading, and generally has a characteristic that shear heat generation is smaller than that of the kneading disk segment and kneading can be performed at a low temperature. . The kneading disc segment and the rotor segment are used for the purpose of imparting stronger shear to the material compared to the screw segment and promoting the melting, dispersion and distribution of the polymer.

  The screw is preferably provided with a kneading disk element. The types of kneading disc elements are classified as feed, reverse feed and neutral. The kneading disc is twisted and attached for feed and reverse feed. Those that twist in the direction opposite to the screw rotation direction (feed) have high feeding ability and the dispersion effect is weak, and those that twist in the screw direction and forward direction have strong backflow (reverse feed) and high dispersion stress. . Neutral is a shape in which the kneading disc is orthogonal, and is intermediate between feed and reverse feed. Further, the paddle width constituting each element is narrow, wide, and combinations thereof. The kind, shape and paddle width of these kneading disk elements affect the behavior of the dispersion and mixing shearing of the resin inside the extruder. In order not to generate the gel, it is preferable to have low shear, low filling, and low residence time. Therefore, it is effective to use a paddle having a narrow width by using a feed screw. In addition, there are various kinds of special kneading disks, but they may be used. In the present invention, the screw can be configured by adding kneading disk segments as appropriate, with the screw segment as a main component so as to satisfy the range defined by the method for producing a thermoplastic resin of the present invention.

  There are also types of kneading screw shapes. For example, a reverse screw having a groove opposite to a normal feed screw has a reverse flow, so that the upstream pressure can be increased. Since the upstream is filled by increasing the pressure, a strong shearing stress is generated by the flowing resin and the residence time becomes long, so that deterioration of the mixed resin is promoted. For this reason, in order to suppress generation | occurrence | production of a gel, a reverse screw is not suitable and it is preferable to use a feed screw. However, only when kneading performance such as filler kneading is required, a reverse screw may be used as long as both kneadability and gel suppression can be achieved.

  In the method for producing the thermoplastic resin composition of the present invention, the kneading strength can be freely changed by changing the length (amount) of the kneading disk in the screw of the multi-screw kneading extruder. When a melt film is formed using pellets with a small amount of volatilization component, the volatilized product is difficult to adhere to the film surface, and the distribution (deviation) of the contact angle of the film can be reduced.

  The kneading disc screw may be a forward feed element (feed screw), a reverse feed element (reverse screw), or neutral, but the screw may stay as a forward feed element. This is preferable in that the time can be shortened and the deterioration of the resin and the generation of gel can be suppressed.

  The shape of the kneading disk used in the present invention is disclosed in JP-A Nos. 2004-17414, 2002-86541, 5-104610, JP-A-5-237914, JP-A-6-55612, and JP-A-6-6-1. 126809, Japanese Utility Model Laid-Open No. 6-68816, Japanese Patent Laid-Open No. 8-258110, Japanese Patent Laid-Open No. 9-136345, Japanese Patent Laid-Open No. 11-10639, Japanese Patent Laid-Open No. 2000-156629, Japanese Patent Laid-Open No. 2001-162671, Japanese Patent Laid-Open No. 2002-338728. And JP-A-2003-39527, JP-A-2003-62892, JP-A-2004-284195, and JP-A-2007-182041 are preferably used. Among these, those described in JP-A Nos. 2004-17414 and 2002-86541 are more preferable.

  Moreover, it is preferable that the temperature of the thermoplastic resin composition after melt-kneading a thermoplastic resin and an additive with a kneading disk is Tg + 80 degreeC-Tg + 130 degreeC. More preferably, it is Tg + 80 degreeC-Tg + 120 degreeC. Such a thermoplastic resin composition close to a molten state can be easily removed by evacuation of volatilized materials and deteriorated products derived from unstable parts of the thermoplastic resin composition, and the melt viscosity of the resin composition in a nearly molten state. Is low, it is difficult to stay, and generation of gels and deteriorated foreign substances can be suppressed.

(Step of cooling and solidifying the melt-kneaded composition)
When the melt-kneaded composition is cooled and solidified, it is preferably prepared by melt-kneading the composition and then extruding it from a die into a noodle shape and solidifying and cutting in air or water. Further, after melting by an extruder, it is preferable to cool and solidify by an underwater cutting method or the like in which it is cut while being directly extruded from a die into water, and pelletized.
The number of rotations of the extruder is preferably 10 rpm to 1000 rpm, more preferably 20 rpm to 700 rpm. Moreover, there is no restriction | limiting in particular as said die | dye, A well-known die | dye can be used.
No particular limitation is imposed on the size of the pellets is generally about 10mm ³ ~1000mm ^3, more preferably about 30 mm ³ 500 mm ^3.

  In the production method of the present invention, the solidified composition preferably contains 0.1 to 20% by mass of the additive, more preferably 0.3 to 18% by mass, and 0.5 to 15% by mass. It is particularly preferable to include it.

(Configuration of multi-screw extruder)
FIG. 1 shows the configuration of the twin screw extruder 22. As shown in the figure, the twin screw extruder 22 is a twin screw type vent type extruder and includes two screws 48 and 48 in a cylinder 42. Each screw 48 is configured by attaching a screw blade 46 to a screw shaft 44, is rotatably supported, and is rotationally driven by a motor (not shown). The twin-screw extruder 22 may be one in which two screw shafts 44, 44 are arranged in parallel, or one in which the two screw shafts 44, 44 are inclined. Also good. Further, the two screw shafts 44, 44 may be rotated in the same direction or in different directions. Then, from the vent holes 54 and 56, volatile components, resin degradation products, residual monomers, and moisture contained in the thermoplastic resin composition in the melting process are removed.

  A jacket (not shown) is attached to the outer peripheral portion of the cylinder 42 so that the temperature can be controlled to a desired temperature. This temperature control is controlled so that the resin temperature does not exceed the resin deterioration temperature due to shearing heat generation. A hopper is provided at a supply port 50 of the cylinder 42 via a not-shown quantitative supply device (feeder), and a thermoplastic resin and an additive are supplied from the hopper, and are supplied into the cylinder 42 through the quantitative supply device. .

  The above-described thermoplastic resin is supplied into the cylinder 42 via the supply port 50 of the twin screw extruder 22. Inside the cylinder 42, in order from the supply port 50 side, a supply unit (area indicated by A1) for quantitatively transporting the thermoplastic resin and additives supplied from the supply port 40, and a compression unit for kneading and compressing the thermoplastic resin composition (Area indicated by A2) and a measuring section (area indicated by A3) for measuring the kneaded and compressed thermoplastic resin composition.

  For example, the screw compression ratio of the extruder 22 is preferably set to 1.1 to 4.0, and L / D is preferably set to 20 to 100. Here, the screw compression ratio refers to the degree to which the molding material is compressed in a molten state for kneading under back pressure, and the volume ratio between the supply unit A1 and the metering unit A3 (that is, the unit length of the supply unit A1). Per volume / volume per unit length of the measuring portion A3), and the outer diameter d1 of the screw shaft 44 of the supplying portion A1, the outer diameter d2 of the screw shaft 44 of the measuring portion A3, and the groove diameter a1 of the supplying portion A1. And the groove part diameter a2 of the measuring part A3. L / D is the ratio of the length (L) of the cylinder 42 to the cylinder inner diameter (D) in FIG. When the temperature in the twin screw extruder 22 exceeds the resin deterioration temperature, a cooler (not shown) may be provided between the twin screw extruder 22 and the die.

In addition, if the screw compression ratio is 1.1 or more or L / D is 20 or more, the thermoplastic resin and the additive are sufficiently kneaded, and the volatilized substance derived from the unstable part of the thermoplastic resin composition In addition, it is sufficient to remove degradation products derived from pyrolysis of thermoplastic resin. On the contrary, when the screw compression ratio is 4.0 or less, the shear stress is not excessively applied, and the resin is hardly deteriorated by suppressing the heat generation, so that a deteriorated resin is hardly produced. Further, if the shear stress is not excessively applied, the molecules are not easily cut and the molecular weight is unlikely to decrease, so that the mechanical strength of the film does not decrease, which is preferable. If L / D is 100 or less, the residence time of the resin will not be too long, and it will be difficult for the resin to deteriorate.
In order to prevent volatilization derived from the unstable part of the thermoplastic resin composition and to make the thermoplastic resin difficult to deteriorate, the screw compression ratio is preferably in the range of 1.1 to 4.0, more preferably. Is in the range of 1.2 to 3.8, particularly preferably in the range of 1.5 to 3.5.

  The residence time of the thermoplastic resin melt in the multi-screw extruder of the present invention is preferably 30 seconds to 600 seconds, more preferably 40 seconds to 400 seconds, still more preferably 50 seconds to 300 seconds. The first residence time is obtained by measuring the time from when the thermoplastic resin material and the additive are supplied to the multi-screw extruder to when the melt comes out from the multi-screw extruder outlet (die).

<Melting extrusion>
In the production method of the present invention, the thermoplastic resin-containing composition containing the solidified composition is melt-extruded from a die. Furthermore, in the production method of the present invention, it is preferable to use pellets as the solidified composition. Prior to melt extrusion, the thermoplastic resin composition is preferably pelletized (or re-pelletized). Commercially available thermoplastic resins (for example, TOPAS # 6013, Toughlon MD1500, Delpet 980N, DayLark D332, etc.) may be pelletized, but if not pelletized, the following method may be used. it can. The thermoplastic resin composition produced by the method for producing a thermoplastic resin composition of the present invention and the thermoplastic resin composition of the present invention can also be pelletized (or repelletized) by the following method.

In the production method of the present invention, in the step of melt-extruding the thermoplastic resin-containing composition containing the solidified composition from a die, the solidified composition is 30 to 100 with respect to the entire thermoplastic resin-containing composition. It is preferable to use mass%, and the thermal decomposition component can be greatly suppressed. If the said ratio is 30% or more, since durability of the optical characteristic of the film obtained improves remarkably, it is preferable.
As for the said ratio, it is more preferable that it is 50-100 mass%, and it is especially preferable that it is 70-100 mass%.

  Moreover, it is possible to produce the film of the present invention at low cost by combining the re-pelletized pellets with commercially available thermoplastic resin pellets other than the present invention, which is preferable.

  In the production method of the present invention, from the viewpoint of controlling the durability of optical properties within the preferred range, the additive is preferably contained in an amount of 0.1 to 20% by mass with respect to the entire thermoplastic resin-containing composition. , 0.3 to 18% by mass is more preferable, and 0.5 to 15% by mass is particularly preferable.

The thermoplastic resin composition is dried, melted at 150 ° C. to 300 ° C. using a twin-screw kneading extruder, and then extruded into noodles, and solidified in air or water and cut. Further, after melting by an extruder, it can be pelletized by an underwater cutting method in which it is cut while being directly extruded from a die into water.
Extruders used for pelletization include single screw extruders, non-meshing different direction rotating twin screw extruders, meshing different direction rotating twin screw extruders, and meshing same direction rotating twin screw extruders. Etc. can be used. The number of revolutions of the extruder is preferably 10 rpm to 1000 rpm, more preferably 20 rpm to 700 rpm. The extrusion residence time is 10 seconds to 10 minutes, more preferably 20 seconds to 5 minutes.
No particular limitation is imposed on the size of the pellets is generally about 10mm ³ ~1000mm ^3, more preferably about 30 mm ³ 500 mm ^3.

  It is preferred to reduce the moisture in the pellets prior to melt extrusion. A preferable drying temperature is 40 to 200 ° C, more preferably 60 to 150 ° C. Thereby, the moisture content is preferably 1.0% by mass or less, and more preferably 0.1% by mass or less. Drying may be performed in air, nitrogen, or vacuum.

  Next, the dried pellets are supplied into the cylinder through the supply port of the film-forming extruder, and are kneaded and melted. For example, the inside of the cylinder of the extruder includes a supply unit, a compression unit, and a metering unit in order from the supply port side. The screw compression ratio of the extruder is preferably 1.5 to 4.5, the ratio of the cylinder length to the cylinder inner diameter (L / D) is preferably 20 to 70, and the cylinder inner diameter is preferably 30 mm to 150 mm. The extrusion temperature of the die (hereinafter also referred to as the discharge temperature) is determined according to the melting temperature of the thermoplastic resin, but generally it is preferably about 190 to 300 ° C. Furthermore, in order to prevent the molten resin from being oxidized by residual oxygen, it is also preferable to carry out the inside of the extruder in an inert (nitrogen or the like) air flow or while evacuating using an extruder with a vent.

  It is preferable to provide a filtration apparatus incorporating a breaker plate type filtration or a leaf type disk filter for filtering foreign matter in the thermoplastic resin composition. Filtration may be performed in one stage or may be performed in multistage filtration. The filtration accuracy is preferably 15 μm to 3 μm, more preferably 10 μm to 3 μm. It is desirable to use stainless steel as the filter medium. As the configuration of the filter medium, a knitted wire, a sintered metal fiber or metal powder (sintered filter medium) can be used, and among them, a sintered filter medium is preferable.

  In order to reduce the fluctuation of the discharge amount and improve the thickness accuracy, it is preferable to provide a gear pump between the extruder and the die. Thereby, the resin pressure fluctuation width in the die can be within ± 1%. In order to improve the quantitative supply performance by the gear pump, a method of controlling the pressure before the gear pump to be constant by changing the number of rotations of the screw can also be used.

  The molten resin is melted by the extruder configured as described above, and the molten resin is continuously fed to the die via a filter and a gear pump as necessary. The die may be any of a T die, a fish tail die, and a hanger coat die. It is also preferable to insert a static mixer immediately before the die to increase the uniformity of the resin temperature.

The clearance of the die exit portion is generally 1.0 to 30 times the film thickness, preferably 5.0 to 20 times.
In the manufacturing method of the present invention, the radius of curvature of the tip of the die lip is not particularly limited, and a known die can be used.

It is preferable that the die can be adjusted in thickness at intervals of 5 to 50 mm. An automatic thickness adjustment die that calculates downstream film thickness and thickness deviation and feeds back the results to die thickness adjustment is also effective.
In addition to the single layer film forming apparatus, it is also possible to manufacture using a multilayer film forming apparatus.
Thus, the residence time from when the resin enters the extruder through the supply port until it exits from the die is preferably 3 to 40 minutes, more preferably 4 to 30 minutes.

<Cast>
Next, the melt of the thermoplastic resin is extruded from the die into a film, and the melt-extruded melt is continuously sandwiched between the first sandwiching surface and the second sandwiching surface constituting the sandwiching device, and then cooled and solidified. To obtain a film. At this time, from the viewpoint of stabilization of productivity, one of the first clamping surface and the second clamping surface is peeled off from the melt first, and then the melt is peeled off from the other surface. preferable. In the manufacturing method of the present invention, the moving speed of the first pressing surface is faster than the moving speed of the second pressing surface, but the surface to be peeled first is the second pressing surface even if it is the first pressing surface. However, from the viewpoint of suppressing the peeling dan, it is preferable that the first surface to be peeled first is the first pinching surface (pressing surface having a high moving speed).

  In the manufacturing method of the present invention, in addition to the conventional method in which a melt melt-extruded from a die is continuously pressed between a first pressing surface and a second pressing surface constituting a pressing device to form a film. The film having the optical characteristics of the present invention is produced by applying a pressure of 20 to 120 MPa between the clamping devices. A preferable roll pressure is 20 to 100 MPa, and a more preferable pressure is 30 to 90 MPa. If the pressure is 20 MPa or more, Re [0 °] and γ are within the scope of the present invention, and ΔRe [0 °] and ΔRth are also within the scope of the present invention. If the said pressure is 25 Mpa or more, since Rth will also express to the preferable range, it is more preferable. If the pressure is 120 MPa or less, Re [0 °], γ, Rth, ΔRe [0 °], and ΔRth are preferably within the scope of the present invention.

In the manufacturing method of the present invention, the moving speed ratio between the first clamping surface and the second clamping surface of the clamping device defined by the following formula (1) is adjusted to 0.75 to 0.99, and the molten resin is sandwiched. It is preferable to apply a shear stress when passing through the pressure device to produce the film of the present invention. The moving speed ratio of the clamping device is more preferably 0.75 to 0.98.
Movement speed ratio = speed of second clamping surface / speed of first clamping surface (1)
If the moving speed ratio is 0.75 or more, ΔRe [0 °] and ΔRth are further improved, and if the moving speed ratio is 0.99 or less, sufficient shear stress can be applied to the melt. Since ΔRe [0 °] and ΔRth are remarkably improved as compared with the case of constant speed, it is preferable.

(Discharge temperature)
In the production method of the present invention, the discharge temperature (resin temperature at the die outlet) is preferably Tg + 50 to Tg + 200 ° C., more preferably Tg + 70 to Tg + 180 ° C., from the viewpoint of improving the moldability of the resin and suppressing deterioration. Tg + 90 to Tg + 150 ° C. is particularly preferable. That is, if Tg + 50 ° C. or higher, the viscosity of the resin is sufficiently low and the moldability is good, and if Tg + 200 ° C. or lower, the resin is less likely to deteriorate.

(Air gap)
In the production method of the present invention, the air gap (distance from the die outlet to the melt landing point of the pinching device) is preferably as close as possible from the viewpoint of heat retention of the melt between the die and the pinching device, Specifically, the thickness is preferably 10 to 300 mm, more preferably 20 to 250 mm, and particularly preferably 30 to 200 mm.

(Film forming speed)
In the production method of the present invention, the film forming speed (line speed) is preferably 10 to 50 m / min, and preferably 12 to 40 m / min from the viewpoint of generating an air flow near the touch roll and removing the pyrolyzate. It is more preferable, and it is especially preferable that it is 14-33 m / min. As the line speed increases, cooling of the melt in the air gap can be suppressed, and more uniform shear deformation can be imparted by the two rolls in a state where the melt temperature is high. On the other hand, if it is 50 m / min or less, there is no need to increase the screw rotation speed in the melt-kneader and the resin is not decomposed due to the increased shearing force of the screw. This is preferable.
In addition, the said conveyance speed represents the speed at which a melt passes between two rolls, and the film conveyance speed in a conveying apparatus.

  In the production method of the present invention, the width of the film-like melt is not particularly limited, and can be, for example, 200 to 2000 mm.

(Cast using two rolls)
Among the methods in which the melt-extruded melt is continuously pressed between a first pressing surface and a second pressing surface constituting a pressing device to form a film, two rolls (for example, a touch roll ( It is preferable to pass between the first roll) and the chill roll (second roll)). In addition, in this specification, when it has multiple casting rolls which convey the said melt, the casting roll nearest to the most upstream die | dye is also called a chill roll. Hereinafter, the preferable aspect of the manufacturing method of this invention using two rolls is demonstrated.

  In the method for producing a film of the present invention, there is no particular limitation on the landing point of the melt extruded from the die, and the landing point of the melt extruded from the die is closest to the touch roll and the cast roll. The distance from the vertical line passing through the midpoint of the gap in the portion may be zero or may be shifted. The landing point of the melt refers to a point where the melt extruded from the die comes into contact (landing) with the touch roll or chill roll for the first time. The midpoint of the gap between the touch roll and the cast roll refers to the midpoint of the touch roll surface and the cast roll surface where the gap between the touch roll and the cast roll is the narrowest.

  The surface of the two rolls (for example, a touch roll or a casting roll) preferably has an arithmetic average height Ra of 100 nm or less, more preferably 50 nm or less, and further preferably 25 nm or less.

  In the production method of the present invention, the width of each of the two rolls is not particularly limited, and can be freely changed and employed according to the width of the film-like melt.

  The roll pressure between the two rolls is preferably 20 MPa to 120 MPa, more preferably 25 MPa to 90 MPa, and even more preferably 30 MPa to 85 MPa. If the pressure is 20 MPa or more, Re [0 °] and γ are within the scope of the present invention, and ΔRe [0 °] and ΔRth are also within the scope of the present invention. If the said pressure is 25 Mpa or more, since Rth will also express to the preferable range, it is more preferable. If the pressure is 120 MPa or less, Re [0 °], γ, Rth, ΔRe [0 °], and ΔRth are preferably within the scope of the present invention.

  In the manufacturing method of the present invention, in order to pressurize the roll pressure in the above range, the cylinder set value is appropriately changed. The cylinder set value varies depending on the resin material used and the material of the two rolls. For example, when the effective width of the film-like melt is 200 mm, it is preferably 3 to 100 KN, and preferably 3 to 50 KN. Is more preferable, and 3 to 25 KN is particularly preferable.

In the production method of the present invention, in order to pressurize the roll pressure in the above range, it is preferable to use a roll having a roll hardness of 45 HS or more. The Shore hardness of the two preferable rolls is preferably 50 HS or more, and more preferably 60 to 90 HS.
The Shore hardness can be determined from the average value of values measured at 5 points in the roll width direction and 5 points in the circumferential direction using the method of JIS Z 2246.

The material of the two rolls is preferably a metal from the viewpoint of achieving the Shore hardness, more preferably stainless steel, and a roll whose surface is plated is also preferred. Moreover, if the material of two rolls is a metal, since the surface unevenness | corrugation is small and the surface of a film is hard to be damaged, it is preferable. On the other hand, a rubber roll or a metal roll lined with rubber can be used without particular limitation as long as the roll pressure can be achieved.
As for the touch roll, for example, JP-A-11-314263, JP-A-2002-36332, JP-A-11-235747, WO97 / 28950, JP-A-2004-216717, JP The thing of 2003-145609 gazette can be utilized.

Furthermore, in the production method of the present invention, by adjusting the peripheral speed ratio of the two rolls through which the film-like melt passes, a shear stress is applied when the molten resin passes through the two rolls. It is preferable to produce a film. The peripheral speed ratio between the two rolls is preferably 0.75 to 0.99, and more preferably 0.75 to 0.98. Here, the peripheral speed ratio of the two rolls means the peripheral speed of the slow roll / the peripheral speed of the fast roll.
If the moving speed ratio is 0.75 or more, ΔRe [0 °] and ΔRth are further improved, and if the moving speed ratio is 0.99 or less, sufficient shear stress can be applied to the melt. Since ΔRe [0 °] and ΔRth are remarkably improved as compared with the case of constant speed, it is preferable. Moreover, it is preferable to set the peripheral speed ratio of the two rolls to 0.75 to 0.99 because a film having a good smoothness can be stably produced with less scratching on the film surface.
In order to obtain the film of the present invention, whichever speed of the two rolls may be high, when the touch roll is slow, a bank (excess of melt stays on the roll and forms on the roll side). Formed residue) is formed. Since the touch roll has a short contact time with the melt, the bank formed on the touch roll side cannot be sufficiently cooled, and a peeling dan is generated, which easily causes a surface failure. Therefore, it is preferable that the slow roll is a chill roll (second roll) and the fast roll is a touch roll (first roll).

  Furthermore, in the production method of the present invention, it is preferable to use a roll having a large diameter as each of the two rolls. Specifically, two rolls having a diameter of 350 to 600 nm, more preferably 350 to 500 nm are used. Is preferred. When a roll with a large diameter is used, the contact area between the film-like melt and the roll becomes wide, and the time for shearing becomes longer. Therefore, a film with a large difference between Re [+ 40 °] and Re [−40 °] is used. Moreover, it can be manufactured while suppressing variations in Re [0 °], Re [+ 40 °] and Re [−40 °]. In the production method of the present invention, the diameters of the two rolls may be the same or different.

  In the manufacturing method of the present invention, the two rolls are driven at different peripheral speeds. The two rolls may be driven or driven independently. However, in order to suppress variations in Re [0 °], Re [+ 40 °] and Re [−40 °], the two rolls are preferably driven independently. .

Further, in order to increase the difference between Re [40 °] and Re [−40 °], the surface temperature of the two rolls may be made different. A preferable temperature difference is 5 ° C to 80 ° C, more preferably 20 ° C to 80 ° C, and further preferably 20 ° C to 60 ° C. At that time, the set temperature of the two rolls is preferably Tg−70 ° C. to Tg + 20 ° C., more preferably Tg−50 ° C. to Tg + 10 ° C., more preferably Tg−40 ° C., using the glass transition temperature Tg of the resin. Set to ~ Tg + 5 ° C. Such temperature control can be achieved by passing a temperature-controlled liquid or gas through the touch roll.
The glass transition temperature of the thermoplastic resin is measured by adding a resin to a measurement pan using a scanning differential calorimeter (DSC) and raising the temperature from 30 ° C. to 300 ° C. at 10 ° C./min in a nitrogen stream. (1st-run), and then cooled to 30 ° C. at −10 ° C./min, and again heated from 30 ° C. to 300 ° C. at 10 ° C./min (2nd-run). The temperature at which the baseline starts to deviate from the low temperature side in 2nd-run can be obtained as the glass transition temperature (Tg).

In the production method of the present invention, the melt is preferably kept warm until the melt is extruded from the die and comes into contact with at least one of the two rolls to reduce the temperature distribution in the width direction. The temperature distribution in the direction is preferably within 5 ° C. In order to reduce the temperature distribution, a member having a heat insulating function or a heat reflecting function is disposed in at least a part of the passage between the melt die and the two rolls to shield the melt from the outside air. Is preferred. Thus, by arranging the heat insulating member in the passage and shielding it from the outside air, it is possible to suppress the influence of the external environment, for example, wind, and to suppress the temperature distribution in the width direction of the film. The temperature distribution in the width direction of the film-like melt is more preferably within ± 3 ° C., and even more preferably within ± 1 ° C.
Furthermore, when the said shielding member is used, since it can pass between rolls in the state with the high temperature of a film-form melt, ie, a state with low melt viscosity, there also exists an effect which is easy to produce the film of this invention.
The temperature distribution of the film-like melt can be measured with a contact thermometer or a non-contact thermometer.

The said shielding member is provided inside the both ends of two rolls, for example, via the width direction side surface of die | dye, and a clearance gap. The shielding plate may be directly fixed to the side surface of the die, or may be supported and fixed by a support member. For example, the width of the shielding member is preferably equal to or greater than the width of the side surface of the die so that the rising airflow due to heat dissipation of the die can be efficiently blocked.
The gap between the shielding member and the end in the width direction of the film-like melt is preferably narrow so as to efficiently shield the rising airflow flowing along the surface of the roll. More preferably, it is about 50 mm from the part. Note that the gap between the side surface of the die and the shielding member is not necessarily provided, but is preferably formed to an extent that allows airflow in the space surrounded by the shielding member to be discharged, for example, 10 mm or less.
In addition, as the material having a heat insulating function and / or a heat reflecting function, a material excellent in wind insulation and heat retention is preferable. For example, a metal plate such as stainless steel can be preferably used.

  As a method of eliminating variations in Re [0 °], Re [+ 40 °], and Re [−40 °], there is a method of increasing adhesion when a film-like melt comes into contact with a casting roll. Specifically, the adhesion can be improved by combining electrostatic application method, air knife method, air chamber method, vacuum nozzle method and the like. Such an adhesion improving method may be performed on the entire surface of the film-like melt or may be partially performed.

  After film formation in this way, it is preferable to cool the film by using one or more casting rolls in addition to two rolls (for example, a casting roll and a touch roll) that allow the film-like melt to pass through. The touch roll is usually arranged so as to touch the first casting roll on the most upstream side (closer to the die). In general, it is relatively common to use three cooling rolls, but this is not a limitation. The distance between the plurality of casting rolls is preferably 0.3 mm to 300 mm, more preferably 1 mm to 100 mm, and still more preferably 3 mm to 30 mm between the surfaces.

  Further, it is preferable to trim both ends of the processed film. The portion cut off by trimming may be crushed and used again as a raw material. Further, it is also preferable to perform a thickness increasing process (knurling process) on one or both ends. The height of the unevenness due to the thickness increasing process is preferably 1 μm to 50 μm, more preferably 3 μm to 20 μm. Thickening processing may be convex on both sides or convex on one side. The width of the thickness increasing process is preferably 1 mm to 50 mm, more preferably 3 mm to 30 mm. Extrusion can be performed at room temperature to 300 ° C.

  It is also preferable to attach a lami film on one side or both sides before winding. The thickness of the laminated film is preferably 5 μm to 100 μm, more preferably 10 μm to 50 μm. The material is not particularly limited, such as polyethylene, polyester, and polypropylene.

  The winding tension is preferably 2 kg / m width to 50 kg / width, more preferably 5 kg / m width to 30 kg / width.

  The unstretched film thickness of the film obtained by the production method of the present invention is preferably 10 μm to 90 μm, more preferably 20 μm to 80 μm, and further preferably 25 μm to 70 μm. The thinner the film thickness, the smaller the amount of decomposition products per unit area, and the effect of the present invention is easily exhibited.

<Stretching and relaxation treatment>
Furthermore, after film formation by the above method, stretching and / or relaxation treatment may be performed. For example, each process can be implemented by the following combinations (a) to (g).
(A) transverse stretching (b) transverse stretching → relaxation treatment (c) longitudinal stretching (d) longitudinal stretching → relaxation treatment (e) longitudinal (transverse) stretching → lateral (longitudinal) stretching (f) longitudinal (transverse) stretching → lateral (Longitudinal) stretching → relaxation treatment (g) Transverse stretching → relaxation treatment → longitudinal stretching → relaxation treatment Among these, the steps (a) to (d) are particularly preferable.

The transverse stretching can be performed using a tenter. That is, the film is stretched by holding both ends in the width direction with clips and widening the film in the lateral direction. At this time, the stretching temperature can be controlled by sending wind at a desired temperature into the tenter. The stretching temperature is preferably Tg-30 ° C to Tg + 50 ° C, more preferably Tg-20 ° C to Tg + 45 ° C, and even more preferably Tg-10 ° C to Tg + 20 ° C. Moreover, a preferable lateral stretch ratio is 1.05 to 4.0 times, more preferably 1.1 to 3 times, and still more preferably 1.2 to 2.5 times.
By performing preheating before stretching and heat setting after stretching, the Re and Rth distribution after stretching can be reduced, and the variation in orientation angle associated with bowing can be reduced. Either preheating or heat setting may be performed, but both are more preferable. These preheating and heat setting are preferably performed by holding with a clip, that is, preferably performed continuously with stretching.
Preheating can be performed at a temperature about 1 ° C to 50 ° C higher than the stretching temperature, preferably 2 ° C to 40 ° C or less, more preferably 3 ° C to 30 ° C. The preheating time is preferably 1 second to 10 minutes, more preferably 5 seconds to 4 minutes, and even more preferably 10 seconds to 2 minutes. During preheating, it is preferable to keep the width of the tenter substantially constant. Here, “substantially” refers to ± 10% of the width of the unstretched film.
The heat setting can be performed at a temperature lower by 1 ° C. to 50 ° C. than the stretching temperature, more preferably 2 ° C. to 40 ° C., further preferably 3 ° C. to 30 ° C. More preferably, it is less than the stretching temperature and less than Tg. The preheating time is preferably 1 second to 10 minutes, more preferably 5 seconds to 4 minutes, and even more preferably 10 seconds to 2 minutes. During the heat setting, it is preferable to keep the width of the tenter substantially constant. Here, “substantially” refers to 0% (the same width as the tenter width after stretching) to −10% (shrinking by 10% from the tenter width after stretching = reduced width) of the tenter width after stretching. If the width is wider than the stretched width, residual strain tends to occur in the film, which is not preferable.

Longitudinal stretching can be achieved by making the peripheral speed on the outlet side faster than the peripheral speed on the inlet side while heating between two pairs of rolls. Under the present circumstances, the expression of the retardation of the thickness direction can be changed by changing the space | interval (L) between and the film width (W) before extending | stretching. When L / W (referred to as aspect ratio) is 2 to 50 or less (long span stretching), it is easy to produce a film having a small Rth, and when L / W is 0.01 to 0.3 (short span), a film having a large Rth is used. Can be created. In this embodiment, any of long span stretching, short span stretching, and a region between them (intermediate stretching = L / W exceeds 0.3 and 2 or less) may be used. Span stretching and short span stretching are preferred. Further, when aiming at high Rth, it is more preferable to use short span stretching, and when aiming at low Rth, it is distinguished from long span stretching.
The stretching temperature is preferably Tg-30 ° C to Tg + 50 ° C, more preferably Tg-20 ° C to Tg + 45 ° C, and even more preferably Tg-10 ° C to Tg + 20 ° C. Moreover, preferable longitudinal draw ratio is 1.05-4.0 times, More preferably, 1.1-3 times, More preferably, it is 1.2-2.5 times.

Furthermore, dimensional stability can be improved by performing relaxation treatment after these stretching. Thermal relaxation is preferably performed either after film formation, after longitudinal stretching, or after lateral stretching, or both. The relaxation treatment may be performed online continuously after stretching, or may be performed offline after winding after stretching.
Thermal relaxation is (Tg-30) ° C to (Tg + 30) ° C, more preferably (Tg-30) ° C to (Tg + 20) ° C, and more preferably (Tg-15) ° C to (Tg + 10) ° C for 1 second to 10 minutes. More preferably 5 seconds to 4 minutes, still more preferably 10 seconds to 2 minutes, 0.1 kg / m to 20 kg / m, more preferably 1 kg / m to 16 kg / m, still more preferably 2 kg / m to 12 kg / m. It is preferable to carry out while conveying with tension.

[Polarizer]
The polarizing plate of the present invention can be obtained by laminating at least a polarizer (hereinafter also referred to as a polarizing film) on the film of the present invention. Hereinafter, the polarizing plate of the present invention will be described. Examples of the polarizing plate of the present invention include a polarizing plate formed on the surface of a polarizing film for the purpose of two functions of a protective film and viewing angle compensation, and a composite polarizing plate laminated on a protective film such as TAC. Can be mentioned.

  If the polarizing plate of this invention uses the film and polarizer of this invention, there will be no restriction | limiting in particular in a structure. For example, when the polarizing plate of the present invention is composed of a polarizer and two polarizing plate protective films (transparent polymer films) that protect both sides of the polarizer, the film of the present invention may be used as at least one polarizing plate protective film. it can. Moreover, the polarizing plate of this invention may have an adhesive layer for sticking with another member in the at least one surface. Moreover, in the polarizing plate of this invention, if the surface of the film of this invention is an uneven | corrugated structure, it will have an anti-glare (anti-glare) function. Further, the polarizing plate of the present invention has an antireflection film of the present invention in which an antireflection layer (low refractive index layer) is further laminated on the surface of the film of the present invention, and further optical anisotropy on the surface of the film of the present invention. It is also preferable to use the optical compensation film of the present invention in which layers are laminated.

  In general, a liquid crystal display device includes four polarizing plate protective films because a liquid crystal cell is provided between two polarizing plates. The film of the present invention may be used for any of the four polarizing plate protective films, but the film of the present invention is particularly advantageous as a protective film disposed between a liquid crystal cell and a polarizing plate in a liquid crystal display device. Can be used.

  The polarizing plate of the present invention more preferably has a configuration in which a cellulose acylate film, a polarizer and a film of the present invention are laminated in this order. Moreover, the structure which the cellulose acylate film, the polarizer, the film of this invention, and the adhesive layer are laminated | stacked in this order is also more preferable.

(Optical film)
The film of the present invention is used for the optical film of the polarizing plate of the present invention. The film can be surface treated. Examples of the surface treatment method include methods such as corona discharge, glow discharge, UV irradiation, and flame treatment.

(Cellulose acylate film)
As the cellulose acylate film of the polarizing plate of the present invention, a known cellulose acylate film for a polarizing plate is used. For example, a known triacetyl cellulose (TAC) film (for example, Fujitac T-60 manufactured by Fuji Film Co., Ltd.) can be preferably used. The lurose acylate film may be surface treated. Examples of the surface treatment method include saponification treatment.

(Polarizer)
As the polarizer, for example, a film obtained by immersing and stretching a polyvinyl alcohol film in an iodine solution can be used.

  As the polarizer used in the present invention, any appropriate one can be selected as long as the object of the present invention can be achieved. Examples of the polarizer include a uniaxially stretched film obtained by adsorbing a dichroic substance such as iodine or a dichroic dye on a hydrophilic polymer film, a dehydrated polyvinyl alcohol product or a dehydrochlorinated polyvinyl chloride product. And polyene-based oriented films. Examples of the hydrophilic polymer film include a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, and an ethylene / vinyl acetate copolymer partially saponified film. In the present invention, a polarizer in which iodine is adsorbed on a polyvinyl alcohol film is preferable.

  The polarizer preferably further contains at least one of potassium and boron. When the polarizer contains potassium and boron, a polarizer (polarizing plate) having a composite elastic modulus (Er) in a preferable range and having a high degree of polarization can be obtained. For production of a polarizer containing at least one of potassium and boron, for example, a film which is a material for forming a polarizer may be immersed in a solution of at least one of potassium and boron. The solution may also serve as a solution containing iodine.

  Any appropriate molding method can be adopted as a method for obtaining the polyvinyl alcohol film. A conventionally known method can be applied as the molding method. Moreover, a commercially available film can be used as it is for the polyvinyl alcohol film. Examples of commercially available polyvinyl alcohol films include the product name “Kuraray Vinylon Film” manufactured by Kuraray Co., Ltd., the product name “Tosero Vinylon Film” manufactured by Tosero Co., Ltd., and the product manufactured by Nippon Synthetic Chemical Industry Co., Ltd. Names include “Nippon Vinylon Film”.

  Regarding an example of a method for producing a polarizer, for example, a polymer film (raw film) mainly composed of a polyvinyl alcohol resin is immersed in a swelling bath containing pure water and a dyeing bath containing an aqueous iodine solution. Swelling treatment and dyeing treatment are performed while applying tension in the film longitudinal direction with different rolls. Next, the film subjected to the swelling treatment and the dyeing treatment is immersed in a crosslinking bath containing potassium iodide, and is subjected to crosslinking treatment and final stretching treatment while tension is applied in the longitudinal direction of the film with rolls having different speed ratios. Is given. The film subjected to crosslinking treatment is immersed in a washing bath containing pure water by a roll and subjected to a washing treatment. The film subjected to the water washing treatment is dried and wound up after adjusting the moisture content. Thus, the polarizer can be obtained by stretching the original film, for example, 5 to 7 times the original length.

  The polarizer may be subjected to any surface modification treatment in order to improve the adhesion with the adhesive. Examples of the surface modification treatment include corona treatment, plasma treatment, glow discharge treatment, flame treatment, ozone treatment, UV ozone treatment, and ultraviolet treatment. These treatments may be used alone or in combination of two or more.

(Adhesive layer)
The polarizing plate of the present invention may have an adhesive layer as at least one of the outermost layers (such a polarizing plate may be referred to as an adhesive polarizing plate). As a particularly preferred embodiment, a pressure-sensitive adhesive layer for adhering to another member such as another optical film or a liquid crystal cell can be provided on the side of the optical film where the polarizer is not adhered.

(Production method of polarizing plate)
The manufacturing method of the polarizing plate of this invention is demonstrated.
The polarizing plate of the present invention can be produced by bonding one side of the film of the present invention (a surface-treated surface in the case of surface treatment) to at least one side of the polarizer using an adhesive. When the cellulose acylate film, the polarizer, and the film of the present invention are bonded together in this order, the polarizing plate of the present invention can be produced by laminating the polarizer and other films using an adhesive on both sides of the polarizer. . In the manufacturing method of the polarizing plate of this invention, it is preferable that the film of this invention is directly bonded with the polarizer.

  As the adhesive, a known polarizing plate production adhesive can be used. Moreover, the aspect which has an adhesive bond layer between the said polarizer and each film is also preferable. Specific examples of the adhesive include an aqueous solution of polyvinyl alcohol or polyvinyl acetal (eg, polyvinyl butyral) and a latex of a vinyl-based polymer (eg, polybutyl acrylate). A particularly preferred adhesive is an aqueous solution of fully saponified polyvinyl alcohol. The polyvinyl alcohol-based adhesive preferably contains a polyvinyl alcohol-based resin and a crosslinking agent.

  The manufacturing method of the polarizing plate of this invention is not limited to said method, Another method can also be used. For example, JP 2000-171635, JP 2003-215563, JP 2004-70296, JP 2005-189437, JP 2006-199788, JP 2006-215463, JP 2006-227090. JP, 2006-243216, JP 2006-243681, JP 2006-259313, JP 2006-276574, JP 2006-316181, JP 2007-10756, JP 2007-128025, Use methods described in JP 2007-140092, JP 2007-171943, JP 2007-197703, JP 2007-316366, JP 2007-334307, JP 2008-20891, etc. it can. Among these, the methods described in JP2007-316366A and JP2008-20891A are more preferable.

  It is preferable that a protective film is also attached to the other surface of the polarizing film, and the protective film may be the film of the present invention. Moreover, the various films conventionally used as a protective film of a polarizing plate, such as a cellulose acylate film and a cyclic polyolefin polymer film, can be used.

  The polarizing plate of the present invention thus obtained is preferably used in a liquid crystal display device, and may be provided on either the viewing side or the backlight side of the liquid crystal cell, or on both sides. Not. Specific examples of the image display device to which the polarizing plate of the present invention can be applied include a self-luminous display device such as an electroluminescence (EL) display, a plasma display (PD), and a field emission display (FED: Field Emission Display). Can be mentioned. The liquid crystal display device is applied to a transmissive liquid crystal display device, a reflective liquid crystal display device, and the like.

[Liquid Crystal Display]
The film and polarizing plate of the present invention can be used for liquid crystal display devices of various modes. Preferably, it can be used for TN (Twisted Nematic), OCB (Optically Compensatory Bend), ECB (Electrically Controlled Birefringence) mode liquid crystal display devices, and more preferably for TN and ECB mode liquid crystal displays.

  The film of the present invention can be preferably used as a film for optical applications, and can be particularly preferably used as an optical compensation film.

  It can also be set as a laminated | multilayer film by providing another layer to the film of this invention.

  The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

(Measurement method)
Details of the measurement methods used in each Example and Comparative Example are shown below.

(1) Re, Rth, γ
20 points are sampled at intervals of 10 cm in the longitudinal direction and 20 points are equally spaced in the width direction, and Re [0 °], Re [40 °], Re [−40 °], and Rth are measured by the method described above. From these values, γ was calculated.

(2) ΔRe [0 °], ΔRth
A change in Re [0 °] around 500 hours in an environment of 90 ° C. and 10% relative humidity is ΔRe [0 °], and a change in Rth around 500 hours in an environment of 90 ° C. and 10% relative humidity is ΔRth. It was. The measuring method is the same as (1) above.

(Thermoplastic resin)
A-1:
As COC (addition polymerization type norbornene resin), Polyplastics Co., Ltd., TOPAS6013 (trade name), Tg = 136 ° C. was used.
A-2:
COP (ring-opening polymerization type norbornene resin), the compound of Example 1 of International Publication WO98 / 14499, Tg = 136 ° C. was used.
A-3:
As the polycarbonate resin, Idemitsu Kosan Co., Ltd., Toughlon MD1500 (trade name), Tg = 142 ° C. was used.
A-4:
According to the manufacture example 1 of [0222]-[0224] of Unexamined-Japanese-Patent No. 2008-9378 as an acryl-type resin, it synthesize | combines from 2500 g of methyl methacrylate = 7500g and methyl 2- (hydroxymethyl) acrylate, and is lactonized. An acrylic resin having a rate of 98% and Tg = 134 ° C. was used.
A-5:
As the cellulose acylate resin, pellets described in Example 1 of JP-A-2008-87398, Tg = 174 ° C. was used.
A-6:
As the cellulose acylate resin, the resin of Example 101 described in Table 3 of JP 2008-50562 A, Tg = 137 ° C. was used.

(Additive)
B-1:
With respect to 100 parts by weight of the thermoplastic resin composition, IRGANOX-1010 (trade name) manufactured by Ciba Specialty Chemicals Co., Ltd. was used as the stabilizer in the addition amounts shown in Tables 1 and 2 below.
B-2:
With respect to 100 parts by weight of the thermoplastic resin composition, IRGANOX-1010 (trade name) as a stabilizer, 0.6 parts by weight manufactured by Ciba Specialty Chemicals, Sumitizer GP (trade name), manufactured by Sumitomo Chemical Co., Ltd. as stabilizers What added 0.4 weight part was used.
B-3:
IRGANOX-1010 (trade name) as a stabilizer, 0.6 parts by weight manufactured by Ciba Specialty Chemicals, and glycerin tribenzoate as a plasticizer, based on 100 parts by weight of the thermoplastic resin composition. Used in.
B-4:
IRGANOX-1010 (trade name) as a stabilizer, 0.6 parts by weight manufactured by Ciba Specialty Chemicals, as a stabilizer, and bisphenol A diphenyl phosphate as a plasticizer, ADEKA, ADEKA STAB FP700 with respect to 100 parts by weight of the thermoplastic resin composition 3 parts by weight of (trade name), Aerosil R972V (trade name) as silica particles, 0.05 part by weight of Nippon Aerosil Co., Ltd. (primary average diameter 16 nm, apparent specific gravity 90 g / L), LA-31 (ultraviolet absorber) (Trade name) and 1.1 parts by weight of ADEKA manufactured by ADEKA Corporation were used.
B-5:
With respect to 100 parts by weight of the thermoplastic resin composition, IRGANOX-1010 (trade name) as a stabilizer, 1.0 part by weight manufactured by Ciba Specialty Chemicals, and bisphenol A diphenyl phosphate as a plasticizer, ADEKA, ADEKA STAB FP600 What added 10 weight part (brand name) was used.
B-6:
What added 1.0 weight part of IRGANOX-1010 (brand name) and the product made by Ciba Specialty Chemicals as a stabilizer with respect to 100 weight part of thermoplastic resin compositions was used.

[Example 1]
(Kneading process (re-pelletization))
100 parts by weight of thermoplastic resin pellets listed in Table 1 and a hopper of a twin-screw kneading extruder filled with a nitrogen stream after adding additives with the composition and addition amount described in Table 1 and mixing with a blender It was thrown into. The screw of the twin-screw kneading extruder is kneaded in a twin-screw extruder having a screw having a kneading disk while being evacuated at a pressure of 300 rpm and an extrusion rate of 200 kg / hr and 0.1 atm. A resin melt was obtained. The evacuation was performed by attaching an exhaust port to the casing of the twin-screw kneading extruder screw and piping it to a vacuum pump. The obtained thermoplastic resin melt was extruded from a die, solidified in water at 60 ° C., and then cut into a diameter of 3 mm and a length of 2 to 6 mm (mostly 3 mm) to prepare a thermoplastic resin composition pellet. .

(Film formation)
The thermoplastic resin composition pellets were dried at 100 ° C. for 2 hours or more, then supplied to a single screw extruder and melted at 265 ° C.
In order to increase the thickness accuracy of the melted melt resin, a certain amount was sent out using a gear pump. The molten polymer sent out from the gear pump passes through a 5 μm sintered filter to remove foreign matter, and then sent out to a die having slit-like gaps, and touch rolls and cast rolls at Tg-10 ° C and Tg-5 ° C. The film was formed under the conditions shown in Table 1. The solidified sheet was peeled off from the polishing roll and wound on a roll film. In addition, after trimming both ends (each 5% of the total width) immediately before winding, a thickness increasing process (knurling) having a width of 10 mm and a height of 50 μm was applied to both ends. The film forming width was 1.5 m, and the film was wound up 3000 m at a film forming speed of 15 m / min. The diameters of the cast roll and touch roll used were 500 mm and 400 mm, respectively, and the surface roughness Ra was a 25 nm metal roll.

(Characteristics of film)
The characteristics of the obtained film of Example 1 are also shown in Table 1. In addition, the inclination direction which measured Re [+40 degree] and Re [-40 degree] of the film of this invention was all the longitudinal direction of the film.

[Examples 2 to 24, Comparative Examples 1 to 4]
Except that the resin used and the film forming conditions were changed as described in Table 1 below, films of Examples and Comparative Examples were obtained in the same manner as Example 1. During melting before film formation, the cyclic olefin resin was melted at 265 ° C., the polycarbonate resin was melted at 275 ° C., the acrylic resin was 270 ° C., and the cellulose acylate resin was melted at 240 ° C.
The re-pelletized raw material usage rate means the weight% of the added amount of the pellets that have undergone the method for producing the thermoplastic resin composition of the present invention relative to the total amount of the thermoplastic resin pellets used. The pellets that have not undergone the manufacturing method of the plastic resin composition use the same type of resin as the thermoplastic resin pelletized by the manufacturing method of the thermoplastic resin composition of the present invention, and have the same type and amount of additive used. It was used.
The characteristics and durability of the films of each Example and Comparative Example are shown in Table 1 below.

From Table 1, it was found that the films of Examples 1 to 24 all showed good optical properties and the durability of the optical properties was also good.
In Comparative Example 1, the touch pressure was set to the lower limit of the present invention, Re [0 °] and γ were insufficiently expressed, and ΔRe [0 °] and ΔRth both exceeded 10 nm. . In Comparative Example 2, the touch pressure was set to be equal to or higher than the upper limit of the present invention, the expression of Re [0 °] and γ was insufficient, and ΔRe [0 °] and ΔRth both exceeded 10 nm. . On the other hand, the films of Examples 1 to 4 having a touch pressure within the range of the present invention showed good optical characteristics, and the durability of the optical characteristics was also good. In Comparative Example 3, the re-pelletized raw material was 0%, that is, a commercially available pellet was used as it was, and ΔRe [0 °] and ΔRth both exceeded 10 nm. On the other hand, the films of Examples 6 to 8 in which the usage rate of the re-pelletized raw material is within the range of the present invention showed good optical characteristics and the durability of the optical characteristics was also good.
In Comparative Example 4, the peripheral speed ratio between the two rolls was outside the scope of the present invention, and the two rolls were formed at a constant speed. The obtained film exhibited γ (gradient phase difference structure). In addition, both ΔRe [0 °] and ΔRth exceeded 10 nm.
Moreover, from Examples 1-24, it turned out that the film of this invention is a film suitable for an optical use, and can be used suitably especially as an optical compensation film.

Mounting and evaluation on TN liquid crystal panel (production of polarizing plate for TN mode)
A polyvinyl alcohol (PVA) film having a thickness of 80 μm is dyed by immersing in an iodine aqueous solution (30 ° C.) having an iodine concentration of 0.05 mass% and a KI concentration of 3 mass% for 60 seconds, and then boric acid concentration is 4 mass%. The film was longitudinally stretched 5.5 times the original length while immersed in an aqueous solution (55 ° C.) with a KI concentration of 3.5% by mass for 55 seconds, and then dried at 50 ° C. for 4 minutes to obtain a thickness. A 20 μm polarizer was obtained.
Separately, a cellulose acylate film (manufactured by Fuji Film Co., Ltd., Fujitac T60) was immersed and saponified in an aqueous sodium hydroxide solution at 55 ° C. at a concentration of 2.0 mol / L, and then sufficiently washed with water. The sodium oxide was washed away. Then, after being immersed for 1 minute in 35 degreeC dilute sulfuric acid aqueous solution at 0.005 mol / L, it was immersed in water, the dilute sulfuric acid aqueous solution was washed away sufficiently, and it dried at 105 degreeC.
The film surface of Example 1 was subjected to corona discharge treatment, and was attached to one side of the polarizer using a polyvinyl alcohol-based adhesive. The saponified Fujitac T60 was attached to the opposite side of the polarizer using a polyvinyl alcohol adhesive to obtain a polarizing plate.
Each film of Example 19 and Comparative Example 4 was subjected to fighting under the same conditions as Fujitac T60. Using a polyvinyl alcohol-based adhesive, each film / polarizer / Fujitack T60 was bonded to obtain a polarizing plate.

(Production of liquid crystal display device)
A pair of polarizing plates provided on a liquid crystal display device (AQUAS LC-20C1-S, manufactured by Sharp Corporation) using a TN type liquid crystal cell is peeled off, and the films of Example 1 and Example 19 of the present invention are used instead. Each of the polarizing plates prepared using a film was attached to the viewer side and the backlight side one by one through an adhesive so that the film prepared in the present invention was on the liquid crystal cell side. The transmission axis of the polarizing plate on the observer side and the transmission axis of the polarizing plate on the backlight side were arranged so as to be orthogonal to each other. Using the measuring device (EZ-Contrast 160D, manufactured by ELDIM), the manufactured liquid crystal display device was evaluated for viewing angle characteristics (contrast viewing angle characteristics) with a black-and-white contrast ratio exceeding 10, and the vertical and horizontal viewing angles were all 40 °. It was confirmed that this is the case.
On the other hand, the polarizing plate produced using the film of Comparative Example 4 of the present invention is attached to the observer side and the backlight side one by one through an adhesive so that the film of Comparative Example 4 is on the liquid crystal cell side. I attached. The transmission axis of the polarizing plate on the observer side and the transmission axis of the polarizing plate on the backlight side were arranged so as to be orthogonal to each other. When viewing angle characteristics with a black-and-white contrast ratio exceeding 10 were measured, it was confirmed that there was a viewing angle orientation of less than 40 ° in the vertical and horizontal viewing angles.
Thus, when the film of the present invention is used, viewing angle compensation can be performed when it is incorporated in a TN liquid crystal display device.

(Preparation of transflective ECB mode polarizing plate)
A polarizing plate was prepared using the film of the film of Example 1 that was created. Specifically, first, a polarizer was prepared by adsorbing iodine to a stretched polyvinyl alcohol film. Using this polarizer, a 60 μm cellulose acylate film (manufactured by Fuji Film Co., Ltd.), a uniaxially stretched norbornene-based polymer film, and a λ / 2 plate with Re = 270 nm, as shown in FIG. The film of Invention Example 1 was laminated. In this manner, two polarizing plates using the film of Example 1 were produced.
Each film of Examples 18 to 19 and Comparative Example 4 was prepared in the same manner as the film of Example 1 to prepare an ECB mode polarizing plate.

(Production and evaluation of transflective ECB mode liquid crystal display)
Next, an ECB type transflective liquid crystal display device was manufactured using the polarizing plate. The liquid crystal cell used uses ZLI-1695 (manufactured by Merck) as the liquid crystal material, and the liquid crystal layer thickness is 2.4 μm in the reflective electrode region (reflective display portion) and 4.9 μm in the transmissive electrode region (transmissive display portion). did. The pretilt angle at the substrate interface of the liquid crystal layer was 2 degrees, and Δnd of the liquid crystal cell was about 150 nm for the reflective display portion and about 320 nm for the transmissive display portion.
The prepared polarizing plates were arranged above and below the liquid crystal cell as shown in FIG. The arrows in the polarizing plates P1 and P2 indicate the respective absorption axes, the arrows in the retardation film indicate the respective slow axes, and the arrows of the ECB cells indicate the rubbing direction of the rubbing treatment applied to the respective facing surfaces. Here, the 12 o'clock direction is 0 ° and the clockwise direction is +.

Regarding a liquid crystal display device (ECB-LCD) using a polarizing plate having the films of Examples 1, 18, and 19 of the present invention, a viewing angle having a contrast ratio of 10 or more in monochrome display was obtained. Has achieved a viewing angle of 70 ° or more in any of the left, right, top and bottom directions. In addition, the polarizing plates having the films of Examples 1, 18 and 19 were similarly incorporated into a liquid crystal display device (ECB-LCD) in the environment of 90 ° C. and 10% relative humidity for about 500 hours. It was confirmed that the change was less than 10%.
On the other hand, the liquid crystal display device (ECB-LCD) using the film of Comparative Example 4 was confirmed to have a viewing angle azimuth with a viewing angle with a contrast ratio of 10 or more and a vertical and horizontal viewing angle of less than 40 °. Further, the polarizing plate having the film of Comparative Example 4 was similarly incorporated into a liquid crystal display device (ECB-LCD) for about 500 hours in an environment of 90 ° C. and 10% relative humidity, and the change in viewing angle exceeded 30%. It was confirmed.
Thus, when the film of the present invention is used, a large viewing angle compensation can be performed when incorporated in a liquid crystal display device.

It is sectional drawing of an example of the twin-screw extruder which can be used by this invention. It is a top view showing the absorption axis of the polarizing plate, the orientation direction of a liquid crystal cell, and the slow axis of a film in the transflective ECB mode liquid crystal display device of the present invention.

Explanation of symbols

22 Twin Screw Extruder 42 Cylinder 44 Screw Shaft 46 Screw Blade 48 Screw 49 Screw Tip 50 Supply Port 52 Discharge Port 54 Vent Hole 56 Vent Hole A1 Supply Portion A2 Compression Portion A3 Metering Portion D Cylinder Inner Diameter L Screw Length

Claims (8)

A step of melt-kneading a composition containing a thermoplastic resin and an additive;
Cooling and solidifying the melt-kneaded composition below the glass transition temperature of the thermoplastic resin;
Melting and extruding a thermoplastic resin-containing composition containing the solidified composition from a die;
Including a step of continuously pressing the melt-extruded melt between a first pressing surface of a metal roll constituting a pressing device and a second pressing surface of another metal roll to form a film,
The pressure applied to the melt by the clamping device is 25 MPa to 90 MPa, and the moving speed of the first clamping surface is made faster than the moving speed of the second clamping surface. A method for producing a film.   The method for producing a thermoplastic resin film according to claim 1, wherein the composition containing the thermoplastic resin and an additive is a pellet. In the step of continuously pressing the melt-extruded melt between a first pressing surface of a metal roll constituting a pressing device and a second pressing surface of another metal roll to form a film, The method for producing a film according to claim 1 or 2, wherein the pressure device is two rolls having different peripheral speeds. The moving speed ratio of the first pressing surface of the metal roll of the pressing device defined by the following formula (1) and the second pressing surface of another metal roll is 0.75 to 0.99. The manufacturing method of the thermoplastic film as described in any one of Claims 1-3.
Movement speed ratio = speed of second clamping surface / speed of first clamping surface (1)   In the step of melt-extruding the thermoplastic resin-containing composition containing the solidified composition from a die, the solidified composition is used in an amount of 30 to 100% by mass with respect to the entire thermoplastic resin-containing composition. The manufacturing method of the thermoplastic film as described in any one of Claims 1-4.   The method for producing a thermoplastic film according to any one of claims 1 to 5, wherein the solidified composition contains 0.1 to 20% by mass of the additive.   The thermoplastic film according to any one of claims 1 to 6, wherein the additive is at least one selected from a stabilizer, a plasticizer, inorganic fine particles, an ultraviolet absorber, and an optical adjusting agent. Production method.   The thermoplastic resin is at least one selected from a cyclic olefin resin, a cellulose acylate resin, a polycarbonate resin, an acrylic resin, and a styrene resin. A method for producing a thermoplastic film according to item 1.

Images