JP3981811B2 - Method for producing cellulose triacetate film - Google Patents

Description

【００６７】
比較例１は、マット剤液ＢをドープＡに直接混合させたため、マット剤が十分に分散されずに凝集し、フィルム中の異物数が多くなっていると考えられる。
【００６８】
これに対して、実施例は、マット剤Ｂをまず添加剤に混合分散させた後、ドープＡに混合させるので、マット剤が十分に分散混合され、フィルム中の異物数をかなり減少させることができた。
【００６９】
以下に、製膜用ドープＡ、マット剤液Ｂ、紫外線吸収剤液Ｃ、可塑剤Ｄ、トリアジン系の化合物Ｅ、シクロヘキサンtrans-ジカルボン酸エステル系の化合物Ｆ、可塑剤とシクロヘキサンtrans-ジカルボン酸エステル系の化合物との混合物Ｇの調製方法について説明する。
（製膜用ドープＡの調製）
セルローストリアセテート( 酸化度６０. ８％) が１６. ９６重量％、トリフェニルフォスフェート が１. ３６重量％、ビフェニルジフェニルフォスフェート が０. ６８重量％、ジクロルメタン が７０. ４７重量％、メタノール が１０. ５３重量％から成る成分を攪拌溶解した。このドープを片ネル、濾紙( 東洋濾紙（株）製♯６３) 、金巾のセットで濾過後、焼結金属フィルター( 日本精線０６Ｎ公称孔径１０μｍ) で濾過し、さらに焼結金属フィルター( 日本精線１２Ｎ公称孔径４０μｍ) で濾過した。
（マット剤液Ｂの調製）
シリカ( 日本アエロジカル( 株) 製アエロジカルＲ９７２が２. ００重量％、製膜用ドープＡの濾過済みが１０．５３重量％、ジクロルメタン７６．１０重量％、メタノールが１１．３７重量％からなる溶液をアトライターにて体積平均粒径０. ３μｍになるように分散を行った。ここで、体積平均粒径は、堀場製作所製粒度分布測定装置ＬＡ９２０で測定した値を用いた。この液をアストロポア１０μｍ( 富士フイルム( 株) 製) で濾過後、更にアストロポア１０μｍ( 富士フイルム( 株) 製) で濾過した。
（紫外線吸収剤液Ｃの調製）
2(2 ′-ヒドロキシ-3′,5′ジ-tert‐ブチルフェニル)-5-クロルベンゾトリアゾール が５. ３３重量％、2(2 ′-ヒドロキシ-3′,5′ジ-tert‐アミルフェニル)ベンゾトリアゾール が１０. ６７重量％、製膜用ドープＡの濾過済みが２１．０５重量％、ジクロルメタンが５４．７７重量％、メタノール が８．１８重量％の液をアストロポア１０μｍ( 富士写真フイルム( 株) 製) で濾過した。
（可塑剤液Ｄの調製）
トリフェニルフォスフェート が１６．６７重量％、ビフェニルジフェニルフォスフェート が８．３３重量％、製膜用ドープＡの濾過済みが１２．１１重量％、ジクロルメタンが５４．７１重量％、メタノールが８．１８重量％の液をアストロポア１０μｍ( 富士フイルム( 株) 製) で濾過した。
（トリアジン系の化合物液Ｅの調製）
構造式１（図５参照）が１５．３８重量％、製膜用ドープＡの濾過済みが１３．８９重量％、ジクロルメタンが６１．５４重量％、メタノールが９．１９重量％の液をアストロポア１０μｍ( 富士フイルム( 株) 製) で濾過した。
（シクロヘキサンtrans-ジカルボン酸エステル系の化合物液Ｆの調製）
構造式２（図５参照）が１５．００重量％、製膜用ドープＡの濾過済みが１２．１１重量％、ジクロルメタンが６３．４１重量％、メタノールが９．４８重量％の液をアストロポア１０μｍ( 富士フイルム( 株) 製) で濾過した。
（可塑剤とシクロヘキサンtrans-ジカルボン酸エステル系の化合物との混合液Ｇの調製）
構造式２（図５参照）が１０．００重量％、トリフェニルフォスフェート が８．８７重量％、ビフェニルジフェニルフォスフェート が４．４３重量％、製膜用ドープＡの濾過済みが１２．１１重量％、ジクロルメタンが５６．３９重量％、メタノールが８．４３重量％の液をアストロポア１０μｍ( 富士フイルム( 株) 製) で濾過した。
【００７０】
【発明の効果】
以上説明したように、本発明に係るセルローストリアセテートフィルムの製造方法によれば、別々に調製したマット剤液と添加剤液を混合し、さらにこの混合液をドープに混合したので、マット剤が十分に混合分散され、マット剤起因の異物発生を防止できる。また、マット剤と添加物を別々に調製するので、それぞれの量を自由に調整することができる。
【図面の簡単な説明】
【図１】本発明を適用したフィルム製造装置の全体構成を示す概念図
【図２】スタチックミキサーの構成を示す断面図
【図３】紫外線吸収剤の分子構造の一例を示す構造図
【図４】紫外線吸収剤の分子構造の一例を示す構造図
【図５】実施例で使用した化合物の構造式を示す図
【符号の説明】
１０…製造装置、１２…ミキシングタンク、１４…ドープ、１６…ポンプ、１８…濾過装置、２０…送液ライン、２２…第一のインラインミキサー、２４…流延ダイ、２６…添加ライン、２８…第二のインラインミキサー、３０…マット剤液用ライン、３２…ストックタンク、３４…添加剤液用ライン、３６…ストックタンク、３８…流延バンド、３９…ドラム、４０…フィルム、４２…延伸乾燥部、４４…ロール乾燥部、４６…ロール、４８…可動パスロール、５０…エッジポジションコントロール装置、５２…ナーリング付与装置、５４…ローラ、５６…耳切装置、５８…除電器、６０…巻取装置、６２…巻芯、６４…コンタクトロール、６６…ケーシング、６８…エレメント[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a cellulose triacetate film, and more particularly to a method for producing a cellulose triacetate film used in a polarizing plate film, an optical use film, an LCD film, an organic EL film and the like.
[0002]
[Prior art]
Cellulose triacetate film is usually produced by a solution casting method. That is, a film is produced by casting a cellulose triacetate dope (concentrated solution) from a casting die onto an endless support, and stripping the dope from the endless support after the dope is self-supporting. In addition to cellulose triacetate, the film often contains a matting agent, a plasticizer, an ultraviolet absorber (additive), and the like. The matting agent is used for improving the slipperiness and adhesion resistance of the formed film, and the ultraviolet absorber is used for preventing deterioration of the polarizing plate when used for, for example, the polarizing plate. . These components are usually mixed together when preparing the dope.
[0003]
In preparing the dope, first, cellulose triacetate, a plasticizer, a solvent, and a dispersed matting agent are charged and dissolved. After filtering this dope with a filtration device, a UV absorber is mixed and kneaded. A film is produced by casting the dope thus prepared on an endless support.
[0004]
However, in this method, when the dope is filtered, the matting agent is trapped, and the amount of the matting agent may be reduced in the film, or the trapped matting agent may flow out to generate foreign matter due to the matting agent.
[0005]
Various methods have been proposed as measures to prevent this. For example, Japanese Patent Application Laid-Open No. 7-11055 proposes a method in which a matting agent and an ultraviolet absorber are mixed and dispersed together, and this dispersion is mixed with the dope immediately before the casting die. In addition, a method of mixing only the matting agent with the dope immediately before the casting die has been proposed.
[0006]
[Problems to be solved by the invention]
However, in the former method, since the matting agent and the UV absorber are mixed and dispersed together, the mixing ratio of the matting agent and the UV absorber cannot be easily changed. There was a problem that the amount could not be changed arbitrarily. There is also a problem that the amount of dispersion increases.
[0007]
On the other hand, in the latter method, the matting agent is not sufficiently dispersed in the dope, and there is a possibility that foreign matter is generated due to aggregation.
[0008]
  The present invention has been made in view of such circumstances, and provides a method for producing a cellulose triacetate film that can suppress the generation of foreign matter due to a matting agent and can separately adjust the amount of a matting agent and the amount of an additive. Aims to do.
[0009]
[Means for Solving the Problems]
  In order to achieve the above object, the invention according to claim 1 is a method for producing a cellulose triacetate film containing a matting agent and an additive.A matting agent solution is prepared by dispersing a matting agent, and an additive solution is prepared using an additive. The prepared matting agent solution and the prepared additive solution are mixed with a second in-line mixer.Mix continuously, and mix the mixture into cellulose triacetate dopeWith the first inline mixerThe film is produced by continuously mixing and casting the dope.
[0010]
According to the first aspect of the present invention, since the prepared matting agent solution is mixed with the additive solution and further mixed with the dope, the matting agent is sufficiently dispersed and cast. Therefore, the matting agent does not aggregate and foreign matter is not generated. Further, since the matting agent is not mixed when the dope is charged, the matting agent is not collected during the filtration of the dope, and the reduction of the matting agent and the generation of foreign matter due to the matting agent can be prevented.
[0011]
Further, according to the invention of claim 1, since the matting agent solution and the additive solution are separately prepared and mixed, the amount of the matting agent and the amount of the additive can be easily adjusted independently of each other. it can.
[0012]
  Claim 1According to the invention described in, since the mixing of the matting agent liquid and the additive liquid and the mixing of the mixed liquid and the dope are performed by an in-line mixer, it becomes possible to continuously process the production efficiency. Can be improved.
[0013]
As the matting agent applied to the present invention, silicon dioxide and its derivatives are preferable as described in claim 3, and as the additive, an ultraviolet ray comprising a benzotriazole-based compound as described in claims 4-8. Absorbers, phosphate ester plasticizers, triazine compounds, cyclohexane trans-dicarboxylic acid ester compounds, and mixtures thereof are contemplated. When two or more types of additives are used, two types of mixed liquids may be prepared in advance, or one type may be sequentially added using an in-line mixer.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a method for producing a cellulose triacetate film according to the present invention will be described in detail with reference to the accompanying drawings.
[0016]
FIG. 1 is a conceptual diagram showing the overall configuration of a cellulose triacetate film manufacturing apparatus 10 according to the present invention.
[0017]
As shown in the figure, the manufacturing apparatus 10 is provided with a mixing tank 12, and a dope 14 is stored in the mixing tank 12. After the dope 14 is stirred in the mixing tank 12, it is sent out to the filter device 18 by the pump 16 and filtered by the filter device 18. The filtered dope 14 is fed to the first in-line mixer 22 and further to the casting die 24 via the liquid feeding line 20.
[0018]
An addition line 26 is connected to the liquid feeding line 20 between the first in-line mixer 22 and the filtration device 18. The addition line 26 is connected to a second inline mixer 28, and the second inline mixer 28 is connected to a stock tank 32 via a matting agent liquid line 30 and via an additive liquid line 34. It is connected to the stock tank 36. The stock tank 32 is prepared by dispersing an arbitrary amount of matting agent and storing a filtered matting agent solution, and the stock tank 36 is prepared and filtered by preparing an arbitrary amount of UV absorber. The additive liquid is stored. The matting agent solution and the additive solution are fed to the second in-line mixer 28 and mixed. Then, a mixed liquid of the matting agent liquid and the additive liquid is injected into the dope 14 of the liquid feeding line 20 through the addition line 26 and mixed by the first in-line mixer 22.
[0019]
The first and second in-line mixers 22 and 28 may be any device that continuously mixes, and for example, a static mixer is used. The static mixer is a stationary mixer without a drive unit, and as shown in FIG. 2, a plurality of elements 68 having a rectangular plate twisted 180 degrees are provided inside a cylindrical casing 68. . As the element 68, there are a right element 68A and a left element 68B having different twisting directions, and the right element 68A and the left element 68B are alternately arranged in a state of being shifted by 90 °. When two kinds of liquids are fed to the static mixer configured in this way, the two kinds of liquids are divided into two parts by the element 68, and the central part and the peripheral part in the casing 66 along the element 68. Under the conversion operation to be converted and the reversal operation in which the rotation direction is changed for each element 68, it is sufficiently mixed and uniform.
[0020]
The casting band 38 is formed endlessly with a stainless steel plate or the like, and the surface thereof is mirror-finished. The casting band 38 is wound around a pair of drums 39, 39 and travels by rotating at least one of the pair of drums 39, 39. The dope 14 is cast on a running casting band 38 and peeled off after self-supporting. In this embodiment, band casting is adopted, but drum casting may be performed.
[0021]
The film 40 peeled off from the casting band 38 passes through a stretching / drying section 42 by a tenter and a roll drying section 44 and is dried. In particular, in the roll drying unit 44, the film 40 is sufficiently dried by blowing dry air onto the film 40 while conveying the film 40 through the rolls 46, 46,. The film 40 thus dried is guided to the movable path roll 48 at the final stage of the roll drying unit 44, and then the position in the width direction is adjusted by the edge position control device 50.
[0022]
The film 40 whose position has been adjusted is pinched by a pair of rollers 54 and 54 of the knurling applicator 52, and knurling (which is minute unevenness, also referred to as embossing or knurling) is applied to the side end. . Thereby, when the film 40 is wound in a roll shape, it is possible to suppress an end face shift and a blackish failure due to a knurling effect.
[0023]
The film 40 to which the knurling has been applied is subjected to ear cutting by the ear cutting device 56, and the width dimension is accurately aligned. The film 40 that has been subjected to the edge cutting is removed by a static eliminator 58 from the static electricity charged on the film 40, and then wound around the core 62 of the winding device 60 while being pressed by the contact roll 64.
[0024]
Next, the operation of the manufacturing apparatus 10 configured as described above will be described.
[0025]
The matting agent solution and the additive solution are prepared separately, filtered and stored in the stock tanks 32 and 36. After these are mixed in the second inline mixer 28, the mixed solution is mixed with the first inline mixer. 22 is mixed with the dope 14. That is, the matting agent and the additive (ultraviolet absorber) are mixed twice by the first and second in-line mixers 22 and 28, become sufficiently uniform, and the matting agent is not aggregated. Generation of foreign matter can be prevented.
[0026]
Further, since the manufacturing apparatus 10 mixes the matting agent solution with the dope 14 at the subsequent stage of the filtering device 18, the matting agent is not collected in the filtering device 18. Accordingly, it is possible to prevent foreign matters from being generated due to the outflow of the collected matting agent and a decrease in the amount of matting agent.
[0027]
As described above, the manufacturing apparatus 10 according to the present embodiment can prevent the generation of foreign matters due to the matting agent, can uniformly mix and disperse the matting agent, and can knead a stable amount of the matting agent. Therefore, since an appropriate amount of the matting agent is uniformly kneaded into the manufactured film 40, minute irregularities are uniformly formed on the surface of the film 40. As a result, it is possible to reliably prevent scratches and adhesion during transport and handling. Further, the produced film 40 has extremely low optical properties such as high transparency because it contains very little foreign matter, and is suitable for optical use films, for example, protective films for polarizing plates. Therefore, if the film 40 is used, a high quality polarizing plate can be manufactured.
[0028]
In addition, since the manufacturing apparatus 10 of the present embodiment prepares and mixes the matting agent solution and the additive solution separately, the amount of the matting agent or the additive can be freely adjusted independently. . Therefore, the manufacturing apparatus 10 can easily manufacture the film 40 in which the mixing ratio of the matting agent and the additive is different.
[0029]
Further, according to the manufacturing apparatus 10, since the second inline mixer 28 is used for mixing the matting agent solution and the additive solution and the first inline mixer 22 is used for mixing the mixed solution and the dope 14, Process can be performed, and production efficiency is good.
[0030]
In the above-described embodiment, an ultraviolet absorber is used as an additive, but the present invention is not limited to this, and a plasticizer and other additives may be used.
[0031]
Hereinafter, the matting agent, additive, and in-line mixer used in the present invention will be described.
(Matting agent)
Matting agents are fine particles dispersed in the dope in order to prevent scratches or deterioration of transportability when handling the film after preparation, and are also referred to as anti-blocking agents and anti-wrinkle agents. The The matting agent preferably has an average height of protrusions on the surface of 0.005 to 10 μm, more preferably 0.01 to 5 μm. In addition, it is better that there are many protrusions on the surface, but if there are more protrusions than necessary, it becomes a problem and becomes a problem. A preferable protrusion is within a range having an average height of the protrusion, for example, when the protrusion is formed with a spherical or irregular matting agent, the content is 0.5 to 600 mg / m.²And more preferably 1 to 400 mg / m²It is.
[0032]
The matting agent is not particularly limited as long as it is a material exhibiting the above-mentioned function, but preferred specific examples of these matting agents include compounds containing silicon, silicon dioxide, titanium dioxide, zinc oxide, aluminum oxide, Barium oxide, zirconium oxide, strongtium oxide, antimony oxide, tin oxide, tin antimony oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, In addition, calcium phosphate and the like are preferable, and silicon-containing inorganic compounds and zirconium oxide are more preferable. However, since the turbidity of the cellulose triacetate film can be reduced, silicon dioxide is particularly preferably used. As fine particles of silicon dioxide, for example, commercially available products having trade names such as Aerosil R972, R974, R812, 130, 200, 300, R202, OX50, TT600 (manufactured by Nippon Aerosil Co., Ltd.) can be used. As the fine particles of zirconium oxide, for example, those commercially available under trade names such as Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) can be used.
[0033]
Examples of organic compound matting agents include polytetrafluoroethylene, cellulose acetate, polystyrene, polymethyl methacrylate, polypropylene methacrylate, polyethylene carbonate, acrylic styrene resin, silicone resin, polycarbonate resin, benzoguanamine resin, and melamine resin. Polyolefin powder, polyester resin, polyamide resin, polyimide resin, polyfluorinated ethylene resin, and pulverized classification of organic polymer compounds such as starch, among which silicone resin is preferably used. Among the silicone resins, those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, Tospearl 105, Tospearl 108, Tospearl 120, Tospearl 145, Tospearl 3120, Tospearl 240 (manufactured by Toshiba Silicone Co., Ltd.) A commercial product having the trade name of can be used.
[0034]
Alternatively, a high molecular compound synthesized by a suspension polymerization method, a high molecular compound made spherical by a spray drying method or a dispersion method, or an inorganic compound can be used. Moreover, it is also possible to form an antiglare layer by adding 0.1 to 10 μm particles and / or the above-mentioned fine particles having the same material and larger particle diameter. It is preferable to add 0.5 to 20% by mass of fine particles. These fine particles are preferably silicon dioxide such as silica, for example, Silicia manufactured by Fuji Silysia Chemical Co., Ltd. and Nippon Sil E manufactured by Nippon Silica Co., Ltd.
[0035]
It is also preferable to use fine particles having an alkyl group or aryl group having 2 to 20 carbon atoms on the surface of these fine particles of the present technology. The alkyl group preferably has 4 to 12 carbon atoms, and more preferably 6 to 10 carbon atoms. The smaller the number of carbons, the better the dispersibility, and the larger the number of carbons, the less reaggregation when mixed with the dope.
[0036]
Examples of inorganic compounds among fine particles having an alkyl group having 2 to 20 carbon atoms on the surface and fine particles having an aryl group used in the present technology include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, carbonic acid. Mention may be made of calcium, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. Silicon dioxide, titanium dioxide, and zirconium oxide are preferred, with silicon-containing compounds, particularly silicon dioxide being preferred. Silica fine particles whose surface is modified with silicone oil and spherical monodispersed silica fine particles are also preferably used.
[0037]
Fine particles of an inorganic compound having an alkyl group having 2 to 20 carbon atoms on the surface can be obtained, for example, by treating the fine particles of silicon dioxide with octylsilane. The fine particles of an inorganic compound having a phenyl group on the surface can be obtained, for example, by treating the fine particles of silicon dioxide with trichlorophenylsilane.
[0038]
Of the fine particles having an alkyl group having 2 to 20 carbon atoms and fine particles having a phenyl group on the surface, examples of the polymer include a silicone resin, a fluorine resin, and an acrylic resin, and polymethacrylate is particularly preferable. As described above, a compound containing silicon is preferable, but silicon dioxide or a silicone resin having a three-dimensional network structure is particularly preferable, and silicon dioxide is most preferable.
[0039]
It is also a preferred aspect that the matting agent described above is dissolved in advance using a solvent or a binder (preferably cellulose triacetate) or used as a solution dispersed and stabilized in some cases.
[0040]
The primary average particle diameter of these matting agents is preferably 0.001 to 20 μm, more preferably 0.001 to 10 μm, and still more preferably 0.002 from the viewpoint of keeping haze low. 1 μm, particularly preferably 0.005 to 0.5 μm. The measurement of the primary average particle diameter of the fine particles is obtained by a transmission electron microscope. The apparent specific gravity of the fine particles is preferably 70 g / liter or more, more preferably 90 to 200 g / liter, and particularly preferably 100 to 200 g / liter. For example, they are commercially available under the trade names of Aerosil 200 and Aerosil R972V (manufactured by Nippon Aerosil Co., Ltd.), and these can be used.
[0041]
Examples of the method for preparing the dispersion of the matting agent according to the present technology include the following four types. (1) After mixing and stirring the solvent and the matting agent, a matting agent dispersion is prepared with a disperser. (2) After mixing and stirring the solvent and the matting agent, use a disperser to form a matting agent dispersion. Separately, a small amount of cellulose triacetate is added to the solvent and dissolved by stirring, and then the matting agent dispersion is added and stirred. . (3) A small amount of cellulose triacetate is added to a solvent and dissolved by stirring. A matting agent is added thereto and dispersed by a disperser to obtain a matting agent dispersion. (4) A solvent, a cellulose triacetate dope, and a matting agent are stirred and mixed, and then dispersed by a disperser to obtain a matting agent dispersion.
[0042]
The dispersion may be diluted with a solvent or a binder (preferably cellulose triacetate) solution to form a matting agent addition solution. The matting agent dispersion and matting agent addition liquid are preferably filtered. Unlike the filtration after dope (that is, filtration by the filtration device 18), this filtration does not increase the pressure because the viscosity of the additive is low. Therefore, the matting agent held by the filter does not flow out due to the pressure, so that no foreign matter is generated due to the matting agent. Further, the filtration here has an advantage that the diameter of the filter can be selected depending on the matting agent type irrespective of the dope.
[0043]
The concentration of silicon dioxide when the silicon dioxide fine particles are mixed and dispersed with a solvent is preferably 0.1 to 30% by mass, more preferably 0.2 to 20% by mass, and most preferably 0.3 to 10% by mass. preferable.
[0044]
Examples of the solvent used include dichloromethane or a mixture of dichloromethane and lower alcohols, preferably methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol and the like. A solvent used at the time of film formation of cellulose triacetate is preferable.
[0045]
The amount of silicon dioxide fine particles added to cellulose triacetate is preferably 0.01 to 0.3 parts by mass, and more preferably 0.02 to 0.2 parts by mass with respect to 100 parts by mass of cellulose triacetate.
[0046]
Examples of the media disperser include attritors, ball mills, sand mills, and dyno mills. As the medialess disperser, there are an ultrasonic type, a centrifugal type, a high pressure type, and the like.
(Additive)
The ultraviolet absorber is preferably used from the viewpoint of preventing deterioration of the polarizing plate or the liquid crystal when the cellulose triacetate film is used for the polarizing plate or the liquid crystal display member. As the ultraviolet absorber, those excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and having a small absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display properties. Specific examples of ultraviolet absorbers preferably used in the present technology include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. Although the specific example as a benzotriazole type ultraviolet absorber is given, this technique is not limited to these.
[0047]
2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ′ -Tert-butyl-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy -3 ′-(3 ″, 4 ″, 5 ″, 6 ″ -tetrahydrophthalimidomethyl) -5′-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3-tetramethyl) Butyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2,4- Dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis (2-methoxy-4- Droxy-5-benzoylphenylmethane), (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2 ( 2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, (2 (2'-hydroxy-3', 5'-di-tert-amylphenyl) -5-chloro Benzotriazole, 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]^ThreeTriethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate]^Three1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3 , 5-Di-tert-butylanilino) -1,3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]^ThreeOctadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), 1, 3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-tert-butyl-4-hydroxybenzyl)- And isocyanurate. In particular, (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, 2 (2′-hydroxy-3 ′, 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2 (2'-hydroxy-3 ', 5'-di-tert-amylphenyl) -5-chlorobenzotriazole, 2,6-di- tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]^ThreeTriethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] is preferred. Further, for example, hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] K drazine and tris (2,4-di- Phosphorus processing stabilizers such as tert-butylphenyl) phosphite may be used in combination.
[0048]
When an ultraviolet absorber is used as the additive solution, a solution of a solvent and an ultraviolet absorber, or a mixed solution of an ultraviolet absorber of a solvent and a binder (preferably cellulose acetate) is preferable. Examples of the solvent used include dichloromethane or a mixture of dichloromethane and lower alcohols, preferably methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol and the like. A solvent used at the time of film formation of cellulose triacetate is preferable. The concentration of the ultraviolet absorber in the additive liquid is preferably 5 to 30%, more preferably 10 to 20%, by mass. The binder concentration is preferably 0 to 10%, and more preferably 0 to 6%.
[0049]
The addition amount of the ultraviolet absorber is preferably from 0.1 to 10%, more preferably from 0.5 to 6.0% by mass ratio with respect to cellulose triacetate.
[0050]
Further, an ultraviolet absorber described in JP-A-6-148430 can also be preferably used. The ultraviolet absorber described above preferably used in the present technology is highly transparent and excellent in preventing the deterioration of the polarizing plate and the liquid crystal element, and a benzotriazole-based ultraviolet absorber with particularly less unnecessary coloring is preferable. The amount of UV absorber used is not uniform depending on the type of compound and the usage conditions, but usually 1 m of cellulose triacetate film.²It is preferably 0.2 to 5.0 g, more preferably 0.4 to 3.0 g, and particularly preferably 0.6 to 2.0 g.
[0051]
For the cellulose triacetate film of the present technology, an ultraviolet absorber having a melting point of 30 ° C. or higher is preferable, and an ultraviolet absorber having a melting point of 50 ° C. to 200 ° C. is further used. The cellulose triacetate film of the present technology is preferably used for a liquid crystal display member because of high dimensional stability and good ultraviolet cut performance. A liquid crystal display member is a member used for a liquid crystal display device, for example, a polarizing plate, a polarizing plate protective film, a retardation plate, a viewing angle improving film, an antiglare film, an antireflection film, an antistatic film, etc. It is done. Among the above descriptions, the cellulose triacetate film of the present technology is more preferably used in polarizing plates and polarizing plate protective films that have strict requirements on dimensional stability. In particular, as a polarizing plate protective film for recent notebook personal computers and the like, a cellulose triacetate film that has been made thinner than before has been demanded. Even when the film thickness is reduced, in order to sufficiently protect the ultraviolet rays, it is necessary to increase the amount of the ultraviolet absorber used per unit weight than before. The thinned polarizing plate protective film tends to cause elution and precipitation of ultraviolet rays. In particular, the cellulose triacetate film of the present technology containing an ultraviolet absorber having a melting point of 100 ° C. or more has an extremely high merit in the production process because the amount of the ultraviolet absorber is increased and the elution and precipitation are small even when the film is thinned. .
[0052]
The plasticizer is contained in the cellulose triacetate film. As the plasticizer, known plasticizers that can be used for cellulose triacetate can be used. For example, phosphate esters such as triphenyl phosphate, biphenyl diphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, trioctyl phosphate, tributyl phosphate, diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl Phthalic acid esters such as phthalate and di-2-ethylhexyl phthalate, and glycolic acid esters such as triacetin, tributyrin, butyl phthalyl butyl glycolate, ethyl phthalyl glycolate, and methyl phthalyl ethyl glycolate . These plasticizers can be used alone or in combination as necessary. Further, the entire amount can be mixed from the additive solution, or a part can be mixed at the time of the original dope preparation, and the rest can be mixed from the additive solution. In the case of using a part of the original dope mixed with the original dope, the kind and composition of the plasticizer contained in the original dope and the additive solution may be the same or different.
[0053]
When a plasticizer is used as the additive solution, a solution of a solvent and a plasticizer or a mixed solution of a solvent, a binder (preferably cellulose acetate) and a plasticizer is preferable. Examples of the solvent used include dichloromethane or a mixture of dichloromethane and lower alcohols, preferably methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol and the like. A solvent used at the time of film formation of cellulose triacetate is preferable. The concentration of the plasticizer in the additive liquid is, by mass ratio, preferably 5 to 40%, more preferably 15 to 30%. The binder concentration is preferably 0 to 10%, and more preferably 0 to 6%.
[0054]
The ratio of the plasticizer in the completed film is preferably 1 to 20% by mass, particularly preferably 5 to 15%, and most preferably 8 to 15% as a liquid crystal member such as a polarizing plate.
[0055]
The triazine-based compound is used as a material for a biaxial film or a viewing angle widening film, and the compounds shown in FIGS. 3A to 3E are used. When a triazine compound is used as the additive solution, a solution of a solvent and a triazine compound or a mixed solution of a solvent, a binder (preferably cellulose acetate) and a triazine compound is preferable. Examples of the solvent used include dichloromethane or a mixture of dichloromethane and lower alcohols, preferably methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol and the like. A solvent used at the time of film formation of cellulose triacetate is preferable. The concentration of the triazine-based compound in the additive solution is preferably 5 to 30%, more preferably 10 to 20%, by mass ratio. The binder concentration is preferably 0 to 10%, and more preferably 0 to 6%. The ratio of the triazine compound in the completed film is preferably 0.5 to 10% by mass, and more preferably 1 to 8% for a liquid crystal member such as a polarizing plate.
[0056]
As shown in FIG. 4, a cyclohexane trans-dicarboxylic acid ester compound is used as a material for the λ / 4 film. In the case of FIG. 4, the structural formula of the terminal R chain site is -C₇H₁₅And -COO-C₈H₁₇, -COO-C₉H₁₉, -COO-C_TenH_{twenty one},-(CH₂) -COO-C₇H₁₅,-(CH₂)₂-COO-C₇H₁₅,-(CH₂)₂-OCO-C₉H₁₉, -OCO-C_FiveH₁₁, -OCO-C₇H₁₅, -OCO-C₈H₁₇, -OCO-C₉H₁₉, -OCO-C₁₁H_{twenty three}, C₈H₁₇O-C₆H_Four-(CH₂) O-C₆H_Four-O (CH₂) -C₆H_Four-OC₈H₁₇, C₈H₁₇-C₆H_Four-C_FourH₈N₂-C₆H_Four-C₈H₁₇, C₂H_Five-C₆H_Four-C_ThreeH_FiveO₂B-C₆H_FiveAnd the like. When a cyclohexane trans-dicarboxylic acid ester compound is used as the additive, a solvent and a trans-dicarboxylic acid ester compound solution, or a solvent, a binder (preferably cellulose acetate) and a cyclohexane trans-dicarboxylic acid ester A mixed solution with the above compound is preferred. Examples of the solvent used include dichloromethane or a mixture of dichloromethane and lower alcohols, preferably methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol and the like. A solvent used at the time of film formation of cellulose triacetate is preferable. The concentration of the cyclohexane trans-dicarboxylic acid ester compound in the additive liquid is, by mass ratio, preferably 5 to 30%, more preferably 10 to 20%. The binder concentration is preferably 0 to 10%, and more preferably 0 to 6%. The ratio of the cyclohexane trans-dicarboxylic acid ester compound in the finished film is preferably 0.5 to 10% by mass, and more preferably 1 to 5% for a liquid crystal member such as a polarizing plate.
(Inline mixer)
The in-line mixer is an apparatus for performing in-line addition and mixing. For example, an in-line mixer such as a static mixer (manufactured by Noritake, Toray Engineering), SWJ (Toray static type in-pipe mixer Hi-Mixer) or the like is preferably used. It is done.
[0057]
【Example】
Film-forming dope A, matting agent B, ultraviolet absorber C, plasticizer D, triazine compound E, cyclohexane trans-dicarboxylic acid ester compound F, plasticizer and cyclohexane trans-dicarboxylic acid ester compound After preparing the mixture G separately and mixing these by the method shown below, the film was manufactured by the film-forming casting method, and the number of the foreign materials contained in this was compared. Film-forming dope A, matting agent B, ultraviolet absorber C, plasticizer D, triazine compound E, cyclohexane trans-dicarboxylic acid ester compound F, plasticizer and cyclohexane trans-dicarboxylic acid ester compound The mixture G is described at the end of the examples.
[0058]
In Example 1, first, the matting agent liquid B was mixed with the ultraviolet absorbent liquid C using a static mixer (38 elements). Then, the mixed solution was added to the dope A and mixed with a static mixer (42 element). Using this dope, a film having a dry film thickness of 80 μm was obtained by a casting film forming method. The ultraviolet absorber at this time was 1.04% by weight in the dry film. Further, the matting agent was 0.13% by weight in the dry film.
[0059]
In Example 2, the UV absorber was 2.08 wt% in the dry film, and a dry film having a thickness of 40 μm was obtained in the same manner as in Example 1.
[0060]
In Example 3, first, the matting agent B was mixed with the plasticizer D using a static mixer (38 elements). And this liquid mixture was added to dope A, it mixed with the static mixer (42 elements), the ultraviolet absorber C was added to the dope after mixing, and it mixed with the static mixer (36 elements). And the dope after mixing was obtained by the same method as in Example 1 to obtain a film having a dry film thickness of 80 μm. The ultraviolet absorber at this time was 1.04 mass% in the dry film. The matting agent was 0.13 mass% in the dry film, and the plasticizer was 13.0 mass% including the original plasticizer in the dry film.
[0061]
In Example 4, the liquid of matting agent B was mixed with the liquid of triazine compound E by a static mixer (38 elements). A film having a dry film thickness of 80 μm was obtained from this mixed solution in the same manner as in Example 1. At this time, the triazine compound was 4.46% by mass in the dry film. Further, the matting agent was 0.13% by mass in the dry film.
[0062]
In Example 5, the liquid of the matting agent B was mixed with the liquid of the cyclohexane trans-dicarboxylic acid ester compound F with a static mixer (38 elements). A film having a dry film thickness of 80 μm was obtained from this mixed solution in the same manner as in Example 1. The cyclohexane trans-dicarboxylic acid ester compound at this time was 1.76% by mass in the dry film. Further, the matting agent was 0.13% by mass in the dry film.
[0063]
In Example 6, the liquid of the matting agent B was mixed with a mixture G of a plasticizer and a cyclohexane trans-dicarboxylic acid ester compound with a static mixer (38 elements). A film having a dry film thickness of 80 μm was obtained from this mixed solution in the same manner as in Example 1. At this time, the cyclohexane trans-dicarboxylic acid ester compound was 1.71% by mass in the dry film, and the plasticizer was 13.0% by mass including the original plasticizer in the dry film. Further, the matting agent was 0.13% by mass in the dry film.
[0064]
In Comparative Example 1, the matting agent solution B is added to the dope A, mixed with a static mixer (42 elements), the ultraviolet absorber C is added to the mixed dope, and the mixture is mixed with a static mixer (36 elements). did. Then, the mixed dope was cast, formed into a film, and dried to obtain a film having a dry thickness of 80 μm. The proportions of the UV absorber and matting agent in the dry film were the same as in Example 1.
[0065]
The foreign matters in the film were measured and are shown in Table 1. 720cm for measuring foreign matter²Were visually observed, and 10 μm or more were counted at an optical microscope magnification of 200 times. The comparative example is 7.2 cm.²720cm²Converted into
[0066]
[Table 1]

[0067]
In Comparative Example 1, since the matting agent liquid B was directly mixed with the dope A, it is considered that the matting agent is aggregated without being sufficiently dispersed, and the number of foreign matters in the film is increased.
[0068]
In contrast, in the example, the matting agent B is first mixed and dispersed in the additive and then mixed in the dope A, so that the matting agent is sufficiently dispersed and mixed, and the number of foreign matters in the film can be considerably reduced. did it.
[0069]
The following are the film forming dope A, matting agent liquid B, ultraviolet absorber liquid C, plasticizer D, triazine compound E, cyclohexane trans-dicarboxylic acid ester compound F, plasticizer and cyclohexane trans-dicarboxylic acid ester. The preparation method of the mixture G with the compound of a system is demonstrated.
(Preparation of dope A for film formation)
Cellulose triacetate (oxidation degree 60.8%) is 16.96% by weight, triphenyl phosphate is 1.36% by weight, biphenyl diphenyl phosphate is 0.68% by weight, dichloromethane is 70.47% by weight, and methanol is 10%. A component consisting of 53% by weight was dissolved by stirring. This dope is filtered with a piece of paper, filter paper (# 63 manufactured by Toyo Filter Paper Co., Ltd.), and a gold width set, then filtered with a sintered metal filter (Nippon Seisen 06N nominal pore size 10 μm), and further, a sintered metal filter (Nippon Seiki). Line 12N nominal pore size 40 μm).
(Preparation of matting agent solution B)
Silica (Aerological R972 manufactured by Nippon Aerological Co., Ltd.) is 2.00% by weight, the filtered dope A for membrane formation is 10.53% by weight, 76.10% by weight of dichloromethane, and 11.37% by weight of methanol. Dispersion was performed with an attritor so that the volume average particle size was 0.3 μm, where the volume average particle size was a value measured with a particle size distribution measuring apparatus LA920 manufactured by Horiba, Ltd. This solution was used as an astropore 10 μm. After filtration with (Fuji Film Co., Ltd.), the mixture was further filtered with Astropore 10 μm (Fuji Film Co., Ltd.).
(Preparation of UV absorber liquid C)
2 (2′-Hydroxy-3 ′, 5′di-tert-butylphenyl) -5-chlorobenzotriazole is 5.33% by weight, 2 (2′-Hydroxy-3 ′, 5′di-tert-amylphenyl) ) A solution containing 10.67% by weight of benzotriazole, 21.05% by weight of the dope A for membrane formation, 54.77% by weight of dichloromethane, and 8.18% by weight of methanol, 10 μm of astropore (Fuji Photo Film ( Filtered).
(Preparation of plasticizer liquid D)
16.67% by weight of triphenyl phosphate, 8.33% by weight of biphenyl diphenyl phosphate, 12.11% by weight of filtered dope A for film formation, 54.71% by weight of dichloromethane, and 8.18 of methanol The liquid of wt% was filtered through Astropore 10 μm (manufactured by FUJIFILM Corporation).
(Preparation of triazine-based compound liquid E)
Astropore 10 μm is a solution in which structural formula 1 (see FIG. 5) is 15.38 wt%, filtered dope A is 13.89 wt%, dichloromethane is 61.54 wt%, and methanol is 9.19 wt%. The solution was filtered through (manufactured by FUJIFILM Corporation).
(Preparation of cyclohexane trans-dicarboxylic acid ester compound liquid F)
Astropore 10 μm is a liquid having a structural formula 2 (see FIG. 5) of 15.00% by weight, 12.11% by weight of filtered dope A, 63.41% by weight of dichloromethane, and 9.48% by weight of methanol. The solution was filtered through (manufactured by FUJIFILM Corporation).
(Preparation of liquid mixture G of plasticizer and cyclohexane trans-dicarboxylic acid ester compound)
Structural formula 2 (see FIG. 5) is 10.00% by weight, triphenyl phosphate is 8.87% by weight, biphenyl diphenyl phosphate is 4.43% by weight, and dope A for film formation is filtered by 12.11% by weight. %, Dichloromethane (56.39% by weight) and methanol (8.43% by weight) were filtered through Astropore 10 μm (manufactured by FUJIFILM Corporation).
[0070]
【The invention's effect】
As described above, according to the method for producing a cellulose triacetate film according to the present invention, the matting agent solution and the additive solution prepared separately are mixed, and further, this mixing solution is mixed with the dope, so that the matting agent is sufficient. It is possible to prevent the generation of foreign matters due to the matting agent. Moreover, since a mat agent and an additive are prepared separately, each quantity can be adjusted freely.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing the overall configuration of a film manufacturing apparatus to which the present invention is applied.
FIG. 2 is a cross-sectional view showing the structure of a static mixer
FIG. 3 is a structural diagram showing an example of the molecular structure of an ultraviolet absorber.
FIG. 4 is a structural diagram showing an example of the molecular structure of an ultraviolet absorber.
FIG. 5 is a diagram showing the structural formulas of compounds used in Examples.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Manufacturing apparatus, 12 ... Mixing tank, 14 ... Dope, 16 ... Pump, 18 ... Filtration apparatus, 20 ... Liquid feeding line, 22 ... First in-line mixer, 24 ... Casting die, 26 ... Addition line, 28 ... Second in-line mixer, 30 ... matting agent liquid line, 32 ... stock tank, 34 ... additive liquid line, 36 ... stock tank, 38 ... casting band, 39 ... drum, 40 ... film, 42 ... stretch drying , 44 ... roll drying section, 46 ... roll, 48 ... movable path roll, 50 ... edge position control device, 52 ... knurling application device, 54 ... roller, 56 ... ear-cutting device, 58 ... static eliminator, 60 ... winding device, 62 ... winding core, 64 ... contact roll, 66 ... casing, 68 ... element

Claims (8)

In the method for producing a cellulose triacetate film containing a matting agent and an additive,
A matting agent solution is prepared by dispersing a matting agent, and an additive solution is prepared with an additive. The prepared matting agent solution and the prepared additive solution are continuously mixed with a second in-line mixer , A method for producing a cellulose triacetate film, wherein the mixed liquid is continuously mixed with a dope of cellulose triacetate by a first in-line mixer , and the dope is cast to produce a film. The matting agent liquid and the additive liquid are respectively filtered and mixed by the second in-line mixer, and the dope is filtered and mixed by the first in-line mixer. Manufacturing method of cellulose triacetate film.   The method for producing a cellulose triacetate film according to claim 1 or 2, wherein the matting agent is silicon dioxide or a derivative thereof.   The method for producing a cellulose triacetate film according to any one of claims 1 to 3, wherein the additive is an ultraviolet absorber made of a benzotriazole-based compound.   The method for producing a cellulose triacetate film according to any one of claims 1 to 3, wherein the additive is a phosphate ester plasticizer.   The method for producing a cellulose triacetate film according to any one of claims 1 to 3, wherein the additive is a triazine-based compound.   The method for producing a cellulose triacetate film according to any one of claims 1 to 3, wherein the additive is a cyclohexane trans-dicarboxylic acid ester-based compound.   The said additive is a 2 or more types of mixture of the compound of Claims 4-7, The manufacturing method of the cellulose triacetate film of any one of Claims 1-3 characterized by the above-mentioned.

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