JP2003285343A - Method for manufacturing optical thin film and optical thin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a uniform optical thin film which shows a superior film thickness distribution in the width direction and is free from a streak trouble, especially an anti-reflection film with a uniform reflection spectrum in the width direction. <P>SOLUTION: In the method for manufacturing the optical thin film and the anti-reflection film obtained by a coating and drying process using a die on a support, the die has a heat-retaining function and the difference between the retained die temperature and a coater chamber temperature is -2°C to +2°C. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing various optical thin films which require a strict film thickness accuracy and have an ultraviolet blocking effect, a heat ray reflecting effect, an antireflection effect, etc. having a dry film thickness of only 100 nm. The present invention relates to a method for producing a uniform and highly precise optical thin film.

[0002]

2. Description of the Prior Art Optical thin film forming methods such as sputtering and plasma CVD generally have a drawback of poor productivity because they are all batch processes. In recent years, various wet methods such as a roll coater are used. Highly efficient and inexpensive optical thin films have been produced. However, T
There are problems such as streaks in the D direction and variations in film thickness accuracy, and improvements have been made in the method of manufacturing various optical thin films that have an ultraviolet blocking effect, a heat ray reflection effect, an antireflection effect, etc. that require strict film thickness accuracy. It was wanted. When a thin optical material such as an antireflection film is manufactured by coating and drying, the optical function is impaired due to uneven thickness of several nanometers. In particular, since the low refractive index layer is provided on the surface side of the multilayer antireflection film, even a slight variation in thickness causes color unevenness of reflected light. This is because the wet coating amount was 10 μm or less, and the flow rate inside the die was small, so that the protrusion amount at the die outlet varied. As a means for solving this, it has been found that in addition to the accuracy of the die slot gap, it can be improved by making the temperature uniform and the physical properties of the coating liquid.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a uniform optical thin film having an excellent width distribution of a width and no streak defects, particularly an antireflection film having a uniform reflection spectrum of the width. To do.

[0004]

The above objects of the present invention have been achieved by the following constitutions.

1. In a method for producing an optical thin film obtained by coating and drying a support with a die, the die has a heat retaining function, and the difference between the die heat retaining temperature and the coater chamber temperature is from -2 ° C to
A method for producing an optical thin film, wherein the temperature is + 2 ° C.

2. 2. The method for producing an optical thin film as described in 1 above, wherein the die keeping temperature range is 21 ° C. to 26 ° C.

3. In the method for producing an optical thin film obtained by coating and drying a support on a support, the die and the liquid supply pipe have a heat retaining function, and the difference between the die heat retention temperature and the liquid supply temperature is -2 ° C to + 2 ° C. Yes, and the die heat retention temperature range is 21 ° C
The method for producing an optical thin film is characterized in that the temperature is ˜26 ° C.

4. A method for producing an optical thin film, which comprises using a static mixer for the pipe at the die inlet in the production of an optical thin film obtained by coating and drying a support with a die.

5. A method for producing an optical thin film obtained by applying and drying a support on a support using a die, wherein a jacket hot water heat exchanger and a static mixer are used for a die inlet pipe.

6. The accuracy of the slit exit of the die used in the manufacturing method of the optical thin film is 1 as the width distribution of the slit gap.
A method for producing an optical thin film, wherein the variation width per m (maximum value of 10-point average value-minimum value) is 2 μm or less.

7. 7. A method for producing an optical thin film, wherein the length of the lip parallel to the backup roll of the die used in the method for producing an optical thin film is 700 μm to 1300 μm in both upstream and downstream sides of the extrusion coater. The distance (coating gap) from the lip of the extrusion coater to the support using the reduced pressure used in the method for producing an optical thin film is 50 μm to 150 μm, and the reduced pressure is −2.
A method for producing an optical thin film, which is from 00 to -400 Pa.

9. Temperature dependence of viscosity of coating liquid is -2%
/ ° C or more and -0.5% / ° C or less coating solution is used, The manufacturing method of the optical thin film characterized by the above-mentioned.

10. 10. The method for producing an optical thin film as described in any one of 1 to 9 above, wherein the coating film thickness is 5 μm to 13 μm. 11. An optical thin film manufactured by the manufacturing method according to any one of 1 to 10 above.

12. 12. The optical thin film as described in 11 above, wherein the optical thin film is an antireflection film.

The present invention will be described in more detail. According to the invention of claim 1 of the present application, in a method for producing an optical thin film obtained by coating and drying a support with a die, the die has a heat retaining function, and the difference between the die heat retaining temperature and the coater chamber temperature (die heat retaining Temperature-coater chamber temperature) is from -2 ° C to + 2 ° C. It is preferably -1 ° C to + 1 ° C.
Normally, the heat retention of the die is adjusted by passing the heat retention water supply hole in the width direction and flowing the heat retention water of a certain temperature at a certain flow rate. The liquid enters from the supply pipe in the center of the die, is spread in the width direction by the cavity inside the die, and is uniformized and extruded by the slit portion. If there is a temperature difference between the temperature in the liquid supply pipe (= room temperature) and the die, the liquid thickness of the width is cooled (or warmed) by the die, and the temperature of the liquid differs depending on the width. It is caused by different viscosities. When the temperature of the liquid is higher than that of the die, the liquid is cooled inside the die, especially at the ends, and the viscosity at the ends increases. Since the flow inside the slit is a pressure flow and the flow rate is inversely proportional to the viscosity, the flow rate at the end drops and the distribution becomes convex in the center.

According to a second aspect of the present invention, there is provided a method for producing an optical thin film obtained by coating and drying a support using a die,
This is a method for producing an optical thin film in which the difference between the die heat retention temperature and the coater chamber temperature (die heat retention temperature-coater chamber temperature) is -2 ° C to + 2 ° C and the set temperature range is 21 ° C to 26 ° C. Preferably between -1 ° C and + 1 ° C, and a set temperature of 22 ° C
~ 24 ° C. If the room temperature is kept as it is, the phenomenon of local dripping occurs due to the type of solvent used and the difference in evaporation rate in the case of a mixed solvent. When it occurs on the upstream side of the die, it becomes a line. Further, if the temperature is too low, sharp streaks may occur on the downstream side of the die due to insufficient leveling. Therefore, the generation of streaks can be prevented by adjusting the entire temperature to 21 to 26 ° C.

According to a third aspect of the present invention, there is provided a method for producing an optical thin film obtained by coating and drying a support using a die,
The die and liquid supply pipe have a heat retention function, and the difference between the die heat retention temperature and the liquid supply temperature (die heat retention temperature-liquid supply temperature) is -2 ° C to
It is a method for producing an optical thin film in which the room temperature is + 2 ° C and the room temperature is 21 ° C to 26 ° C.

The invention of claim 4 is a method for producing an optical thin film, wherein a static mixer is used for a pipe at the die inlet in the production of an optical thin film obtained by coating and drying a support with a die. Specific examples of the static mixer include those manufactured by Noritake Co., Ltd. having 6 elements.

According to a fifth aspect of the present invention, there is provided a method for producing an optical thin film obtained by coating and drying a support using a die,
This is a method for producing an optical thin film using a hot water heat exchanger with a jacket mechanism and a static mixer in the die inlet pipe. With such a configuration, the inventions of claims 1 to 4 can be easily cleared.

According to the sixth aspect of the invention, in the accuracy of the die slit exit, the width distribution of the slit gap is 2 μm as a variation width per 1 m (maximum value of 10 point average value−minimum value).
This is a method for producing an optical thin film having a thickness of m or less. Normally, the slit gap is set to 100 μm to 400 μm. Two SU
The block made of S is ground in the width direction with high accuracy and the slit surfaces are aligned to adjust the gap. This is because the width distribution becomes exactly the same as the width accuracy at the slit exit of the die. It is preferably 1 μm or less.

The inventions of claims 7 and 8 will be described with reference to FIG. In FIG. 1, lips 1 (downstream) and 1 '(upstream)
Part 2 (downstream) and 2 '(upstream) parallel to the backup roll 4 at the tip of each are 700 μm to 1300 μm
m (distance indicated by 3 in the figure), but preferably 800μ
It is m-1200 micrometers. The distance 6 (coating gap) between the lip end of the extrusion coater and the support 5 is 50μ.
m-150 μm, and the reduced pressure in the upstream part is -200-
-400 Pa, but preferably 80 μm to 120 μm
m, and the pressure reduction in the upstream part is -200 to -300 Pa.
Is. The coating liquid is set to a predetermined temperature using a jacket hot water heat exchanger and a static mixer, and then sent to the die through the inlet pipe and sent to the slit section 7.

The temperature dependence of the viscosity of the coating liquid of the present invention is -2.
% / ° C or more and + 2% / ° C or less. The viscometer was measured by using Yamaichi Denki (FVM80A-EX). The liquid temperature control is preferably measured at a set temperature ± 0.5 ° C.
The temperature dependence of the viscosity showed different results for the two types of liquids as shown in the graph of FIG. Regarding the temperature measurement range, the viscosity in the range of 20 to 30 ° C was plotted when the temperature at 25 ° C was 100%. The liquid A shows a viscosity change rate of ± 2% or less, and the liquid B shows ± 5%.

The coating film thickness of the present invention is preferably 5 μm to 13 μm. If the film thickness immediately after coating is 5 μm or less, it is difficult to apply a uniform coating. On the contrary, if the film thickness is 13 μm or more, the drying period becomes long, various disturbances are likely to occur, and local unevenness occurs. Preferably 7 μm to 12 μm
m.

The optical thin film of the present invention is characterized by being obtained through the above-mentioned manufacturing method. In the present invention,
The optical thin film is preferably an antireflection optical thin film.

A feature of the antireflection optical thin film in the present invention is a laminated body of optical interference layers in which a high refractive layer and a low refractive layer are laminated in that order on at least one surface of the support from the support side (in some cases, other It is possible to add layers of.

With respect to the light having the wavelength λ, the optical film thicknesses of the high-refractive layer and the low-refractive layer are set to λ / 4 to produce the antireflection laminate. The optical film thickness is a quantity defined by the product of the layer refraction n and the film thickness d. The high or low of the refractive index is almost determined by the metal or compound contained therein, and for example,
Ti is high, Si is low, and compounds containing F are even lower, and such a combination sets the refractive index. The refractive index and the film thickness are calculated and calculated by measuring the spectral reflectance.

When a solution containing a metal compound is applied to a support to obtain a film, the antireflection optical characteristics are determined only by the physical film thickness as described above.

Particularly, the color of the reflected light near 550 nm changes between reddish violet and bluish violet when the film thickness deviates by only a few nm. This color unevenness is hardly noticeable when the amount of light transmitted from the display is large, but when the amount of light is small or when the display is turned off, color unevenness is noticeable and the quality deteriorates.

When the deviation of the film thickness is large, 400
The reflectance at ˜700 nm cannot be lowered, and it becomes difficult to obtain desired antireflection characteristics.

[Support] The support used in the present invention is not particularly limited, and examples thereof include a polyester film, a cellulose ester film, a polycarbonate film, a polyether sulfone film, and a norbornene resin film. Of these, a cellulose ester film is preferable in the present invention, and a cellulose ester film stretched in at least one direction is particularly preferable.

Stretching is 1.02 in the machine direction (machine direction).
~ 1.50 times, or 1.02 in the lateral direction (width direction)
It is preferably performed 1.520 times, and more preferably biaxially stretched in the longitudinal and transverse directions.

The stretching method is not particularly limited as long as it can be stretched. For example, a method of passing the web through several closely-spaced rolls, a method of gripping both ends of the web with a clip or the like and stretching in the width direction, and the same method of clipping There is a method of gripping the sheet and widening the clip interval in the traveling direction, and the like, and any of them can be preferably used. The stretching not only increases the strength of the support, but also has the effect of improving the flatness and can improve the uniformity of the reflectance over the entire area of the support as an antireflection optical thin film.

Cellulose as a raw material of the cellulose ester preferably used in the present invention is not particularly limited, and examples thereof include cotton linter, wood pulp, kenaf and the like. The cellulose esters obtained from them can be used alone or as a mixture at an arbitrary ratio, but it is preferable to use 50% by mass or more of cotton linter.

In the cellulose ester, the acylating agent of the cellulose raw material is an acid anhydride (acetic anhydride, propionic anhydride,
Butyric anhydride), the reaction is carried out using an organic acid such as acetic acid or an organic solvent such as methylene chloride and a protic catalyst such as sulfuric acid. The acylating agent is an acid chloride (CH ₃ COCl, C ₂ H ₅ COCl, C ₃ H ₇ C
In the case of OCl), the reaction is carried out using a basic compound such as an amine as a catalyst. Specifically, JP-A-10
It can be synthesized by the method described in JP-A-45804. In the cellulose ester, the acyl group reacts with the hydroxyl group of the cellulose molecule. The cellulose molecule is composed of a large number of glucose units linked together, and each glucose unit has three hydroxyl groups. The number of acyl groups derived from these three hydroxyl groups is called the degree of substitution.

For example, cellulose triacetate has an acetyl group bonded to all three hydroxyl groups of the glucose unit.

The cellulose ester that can be used in the cellulose ester film is not particularly limited, but the total degree of substitution of acyl groups is preferably 2.40 to 2.98, and the degree of substitution of acetyl groups among the acyl groups is preferable. Is 1.4
The above is more preferably used.

The method of measuring the substitution degree of the acyl group is ASTM-
It can be measured according to D817-96.

The cellulose ester is a cellulose acetate such as cellulose triacetate or cellulose diacetate, an acetyl group such as cellulose acetate propionate, cellulose acetate butyrate, or cellulose acetate propionate butyrate, as well as a propionate group or a butyrate group. It is preferably a cellulose ester in which is bonded. Note that butyrate includes iso-in addition to n-. Cellulose acetate propionate having a large degree of substitution of propionate groups has excellent water resistance.

Number average molecular weight Mn of cellulose ester
(The measuring method is described below) is 70,000 to 250,000.
In the range of 00, the mechanical strength of the obtained film is high,
In addition, the dope viscosity is appropriate, which is preferable. Further 80,00
0 to 150,000 is preferable. Further, a cellulose ester having a ratio (Mw / Mn) to the mass average molecular weight Mw of 1.0 to 5.0 is preferably used, and more preferably 1.5.
~ 4.5.

<< Measurement of Number Average Molecular Weight of Cellulose Ester >> It is measured by high performance liquid chromatography under the following conditions.

Solvent: Acetone column: MPW × 1 (manufactured by Tosoh Corporation) Sample concentration: 0.2 (mass / volume)% Flow rate: 1.0 mL / min Sample injection amount: 300 μL Standard sample: Polymethylmethacrylate (mass) Average molecular weight 188,200) Temperature: 23 ° C.

Further, it is preferable that the amount of metal in the cellulose ester used during the production of the cellulose ester during production or mixed in the used material in a small amount is as small as possible, and the total content of metals such as Ca, Mg, Fe and Na is contained. Quantity is 10
0 ppm or less is preferable.

[Organic Solvent] Methylene chloride (methylene chloride), which is a chlorine-based organic solvent, can be mentioned as an organic solvent which dissolves a cellulose ester and is useful for forming a cellulose ester solution or dope. Dissolution of a cellulose ester, particularly cellulose triacetate. Suitable for As the non-chlorine organic solvent, for example, methyl acetate,
Ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1- Propanol, 1,3-difluoro-2-propanol,
1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3 Examples thereof include 3-pentafluoro-1-propanol and nitroethane.

When these organic solvents are used for cellulose triacetate, a dissolving method at room temperature can be used, but by using a dissolving method such as a high temperature dissolving method, a cooling dissolving method, or a high pressure dissolving method. Insoluble matter can be reduced, which is preferable.

For cellulose esters other than cellulose triacetate, methylene chloride can be used, but methyl acetate, ethyl acetate and acetone can be preferably used without using methylene chloride. Methyl acetate is particularly preferable. In the present invention, an organic solvent having good solubility in the above-mentioned cellulose ester is referred to as a good solvent, and also exhibits a main effect on dissolution, in which a large amount of organic solvent is the main (organic) solvent or the main ( Organic) solvent.

In the dope, in addition to the above organic solvent, 1 to 4
It is preferable to contain 0% by mass of an alcohol having 1 to 4 carbon atoms. These are used as a gelling solvent that makes the web gel when the dope is cast on a metal support and the solvent begins to evaporate and the ratio of alcohol increases, and makes the web tough and easy to peel from the metal support. When these proportions are small, it also has a role of promoting the dissolution of the cellulose ester of the non-chlorine organic solvent.

As the alcohol having 1 to 4 carbon atoms,
Methanol, ethanol, n-propanol, iso-
Propanol, n-butanol, sec-butanol,
Mention may be made of tert-butanol.

Of these, ethanol is preferable because it is excellent in stability of the dope, has a relatively low boiling point, has good drying property, and has no toxicity. These organic solvents alone are not soluble in cellulose ester and are therefore called poor solvents.

[Production of Cellulose Ester Film by Solution Casting Method] A method for forming a cellulose ester film used as a support will be described. The cellulose ester film is produced by a solution casting film forming method.

Dissolving step: a step of dissolving the cellulose ester, the polymer and the additives with stirring in an organic solvent mainly composed of a good solvent for the cellulose ester (flakes) to form a dope, or the cellulose ester This is a step of forming a dope by mixing a polymer solution and an additive solution with the solution. To dissolve the cellulose ester, a method carried out under normal pressure, a method carried out below the boiling point of the main solvent,
Method of pressurizing above the boiling point of the main solvent, JP-A-9-95
544, 9-95557 or 9-95538.
Japanese Patent Laid-Open Publication No. 11-1999
Although various dissolution methods such as a high pressure method described in JP-A-21379 can be used, in the present invention, a method of pressurizing above the boiling point of the main solvent is particularly preferable.

The concentration of cellulose ester in the dope is 1
0 to 35 mass% is preferable. An additive is added to the dope during or after the dissolution to dissolve and disperse it, and the dope is filtered through a filter medium, defoamed, and sent to the next step by a liquid sending pump.

Casting step: An endless metal belt, such as a stainless steel belt, or a rotating metal drum, which feeds the dope to a pressure die through a liquid feed pump (for example, a pressurization type fixed gear pump) and transfers it infinitely. This is a step of casting the dope from the pressure die slit at the casting position on the support. It is preferable to use a pressure die that can adjust the slit shape of the die of the die and can easily make the film thickness uniform. The pressure die includes a coat hanger die and a T die, and any of them is preferably used. The surface of the metal support is a mirror surface. In order to increase the film formation speed, two or more pressure dies may be provided on the metal support, and the dope amount may be divided to form multiple layers.

Solvent evaporation step: The web (the dope film is called the web after casting the dope on the metal support) is heated on the metal support until the web can be peeled from the metal support. This is a step of evaporating the solvent. To evaporate the solvent, a method of blowing a wind from the web side and / or
Alternatively, there are a method of transferring heat from the back surface of the metal support by a liquid, a method of transferring heat from the front and back sides by radiant heat, and the like, and the back surface liquid heat transfer method is preferable because of good drying efficiency. A method of combining them is also preferable. In the case of rear surface liquid heat transfer, it is preferable to heat at a temperature not higher than the boiling point of the main solvent of the organic solvent used for the dope or the organic solvent having the lowest boiling point.

Peeling step: This is a step of peeling the web having the solvent evaporated on the metal support at the peeling position. The peeled web is sent to the next step. If the residual solvent amount of the web at the time of peeling (the following formula) is too large, it is difficult to peel, or conversely if you peel it after drying it sufficiently on the metal support, part of the web may peel off in the middle .

As a method for increasing the film forming speed (the film forming speed can be increased by peeling while the residual solvent amount is as large as possible), there is a gel casting method (gel casting).

In the method for drying and producing the optical thin film of the present invention, a cellulose ester film produced by the solution casting film forming method is used as a support, but the solution casting film forming method itself is not particularly limited. , Methods commonly used in the art, eg, US Pat. No. 2,492,97.
No. 8, No. 2,739,070, No. 2,739,0
No. 69, No. 2,492,977, No. 2,336.
No. 310, No. 2,367,603, No. 2,60
7,704, British Patents 64,071, 73
No. 5,892, Japanese Patent Publication No. 45-9074, No. 49-45.
No. 54, No. 49-5614, No. 60-27562,
The methods described in No. 61-39890, No. 62-4208, etc. can be referred to.

The solvent used for preparing the dope solution of the cellulose ester used in the solution casting film formation method may be used alone or in combination of two or more kinds, but a good solvent of the cellulose ester and a poor solvent are mixed. It is preferable to use it in terms of production efficiency, and it is preferable that the amount of the good solvent is large in terms of the solubility of the cellulose ester. The preferable range of the mixing ratio of the good solvent and the poor solvent is 70 to 98% by mass of the good solvent,
The poor solvent is 30 to 2 mass%.

The good solvent and the poor solvent are defined as those in which the cellulose ester used alone is dissolved, and those in which the cellulose ester swells or does not dissolve alone are defined as the poor solvent. Therefore, depending on the average degree of acetylation of the cellulose ester, the target of good solvent and poor solvent changes. For example, when acetone is used as a solvent, the amount of bound acetic acid in the cellulose ester of 55% is a good solvent, and the amount of bound acetic acid is 60. %
Then it becomes a poor solvent.

The good solvent used in the present invention is not particularly limited. For example, in the case of cellulose triacetate, an organic halogen compound such as methylene chloride, dioxolanes, methyl acetate, or cellulose acetate propionate is used. , Methylene chloride, acetone, methyl acetate and the like.

The poor solvent used in the present invention is not particularly limited, but for example, methanol, ethanol, i-propyl alcohol, n-butanol, cyclohexane, acetone, cyclohexanone and the like are preferably used.

As a method for dissolving the cellulose ester in preparing the above dope solution, a general method can be used, but in a range above the boiling point of the solvent under normal pressure and under which the solvent does not boil under pressure. The method of heating at the temperature of 1 and dissolving with stirring is more preferable because it can prevent the generation of undissolved lumps called gel or mamako.

A method in which the cellulose ester is mixed with a poor solvent, moistened or swollen, and then mixed with a good solvent to dissolve the cellulose ester is also preferably used.

The type of the pressurizing vessel is not particularly limited as long as it can withstand a predetermined pressure and can heat and stir under pressure. In addition to the pressure gauge,
Appropriately install thermometers and other instruments. The pressurization may be carried out by a method of injecting an inert gas such as nitrogen gas or by increasing the vapor pressure of the solvent by heating. Heating is preferably performed from the outside. For example, a jacket type is preferable because temperature control is easy.

The heating temperature after the addition of the solvent is preferably not lower than the boiling point of the solvent used at normal pressure and in the range where the solvent does not boil from the viewpoint of the solubility of the cellulose ester, but the heating temperature is too high. Therefore, the required pressure increases and the productivity deteriorates. The preferred heating temperature is 45 to 120.
℃, more preferably 60 ~ 110 ℃, 70 ℃ ~ 1
The range of 05 ° C is more preferable. Also, the pressure is the set temperature,
The solvent is adjusted so that it does not boil.

In addition to the cellulose ester and the solvent, necessary additives such as a plasticizer and an ultraviolet absorber are mixed with the solvent in advance and dissolved or dispersed, and then added to the solvent before the dissolution of the cellulose ester. It may be added to the dope after dissolution.

After the dissolution, the product is taken out from the container while being cooled, or is taken out from the container by a pump or the like and cooled by a heat exchanger and the like, and is used for film formation. At this time, the cooling temperature is cooled to room temperature. However, it is more preferable to cool to a temperature 5 to 10 ° C. lower than the boiling point and perform casting at that temperature because the dope viscosity can be reduced. The method for measuring the degree of substitution of the acetyl group is ASTM-817-96.
It can be measured according to the regulations of.

These cellulose esters are manufactured (film formation) by a method generally called a solution casting film formation method as described later. This method is used for endless metal belts (eg stainless steel belts) or rotating metal drums (eg cast iron chrome-plated drums) that can be transferred indefinitely.
A dope (a cellulose ester solution) is cast from a pressure die onto a casting metal support (hereinafter, also simply referred to as a metal support), and a web (metal casting) on the metal support is cast. The doped film) from the metal support,
It is manufactured by drying.

From the viewpoint of preventing deterioration when the cellulose ester film is placed outdoors as an image display device, it is preferable to contain the ultraviolet absorber described below.

As the ultraviolet absorber, those which are excellent in the ability to absorb ultraviolet light having a wavelength of 370 nm or less and have little absorption of visible light having a wavelength of 400 nm or more can be preferably used. For example, oxybenzophenone compounds, benzotriazole compounds, salicylate compounds, benzophenone compounds, cyanoacrylate compounds,
Examples thereof include nickel complex salt compounds, but the present invention is not limited thereto.

In the present invention, the film thickness of the cellulose ester film is preferably 10 to 500 μm, and particularly preferably 10 to 80 μm.

The thickness of the optical thin film of the present invention is from 1 to 1
000 nm is preferred. In the present invention, when the optical thin film of the present invention is provided on the support surface as described above, it can be provided so that the film thickness deviation with respect to the average film thickness is ± 8%, more preferably within ± 5%. It is possible to form a thin film uniformly within ± 1%.

By laminating multiple thin films by the drying method and manufacturing method of the present invention, it is possible to obtain a uniform optical thin film without unevenness of each layer.

As described above, according to the present invention, it is possible to provide an optical thin film in which thin films having various functions are formed.

In the present invention, as the antistatic layer or the conductive layer, a layer having a thickness of 0.1 to 2 μm coated with conductive resin fine particles such as metal oxide fine particles and crosslinked cationic polymers may be provided.

The optical thin film obtained by the method for drying an optical thin film of the present invention is particularly useful as a polarizing plate protective film, and a polarizing plate can be produced by a known method using this. Since these optical thin films have high uniformity of thin films, they can be preferably used in various display devices and can obtain excellent display performance.

In the optical thin film of the present invention, if necessary, a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, a conductive layer, a light diffusing layer, an easily adhesive layer, an antifouling layer, an easily adhesive layer, Alignment layer,
A liquid crystal layer, an optically anisotropic layer and the like can be provided alone or in combination.

In a liquid crystal display device, it is usually preferable to dispose a substrate containing liquid crystal between two polarizing plates. Particularly, a polarizing plate protective film on the outermost surface of the liquid crystal display device on the display side has a hard coat layer and an antiglare layer. Since a layer, an antireflection layer and the like are provided, it is particularly preferable to use the polarizing plate in this portion.

The optical thin film of the present invention can be easily transported and wound by incorporating a matting agent into a cellulose ester film (support) described later.

The matting agent is preferably as fine particles as possible. Examples of the fine particles include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, and silica. Inorganic fine particles such as aluminum oxide, magnesium silicate, and calcium phosphate, polymethacrylic acid methyl acrylate resin powder, acrylic styrene resin powder, polymethyl methacrylate resin powder,
Silicon-based resin powder, polystyrene-based resin powder, polycarbonate resin powder, benzoguanamine-based resin powder, melamine-based resin powder, polyolefin-based resin powder, polyester-based resin powder, polyamide-based resin powder, polyimide-based resin powder, or polyfluorinated ethylene-based powder Resin powder and the like can be mentioned, but crosslinked polymer fine particles are particularly preferable. The present invention is not limited to these.

Among the above, silicon dioxide is particularly preferable for adjusting the dynamic friction coefficient and is preferable because it can reduce the haze of the film. The average particle diameter of the primary particles or secondary particles of the fine particles is in the range of 0.01 to 5.0 μm, and the content thereof is 0.005 to 0.
5 mass% is preferable.

Fine particles such as silicon dioxide are often surface-treated with an organic substance, but such particles are preferable because they can reduce the haze of the film.

Preferred organic substances for the surface treatment include halosilanes, alkoxysilanes, silazanes, siloxanes and the like. The larger the average particle size of the fine particles, the greater the slippery effect, and the smaller the average particle size, the more excellent the transparency.
It is preferably 0 nm or less, preferably 5 to 16 nm, and particularly preferably 5 to 12 nm.

In the cellulose ester film, these fine particles have 0.0% on the surface of the cellulose ester film.
It is preferable to generate unevenness of 1 to 1.0 μm.

Fine particles of silicon dioxide include Aerosil 200 and 2 manufactured by Nippon Aerosil Co., Ltd.
00V, 300, R972, R972V, R974, R
202, R812, OX50, TT600 and the like, preferably Aerosil 200V, R972,
R972V, R974, R202 and R812. Two or more kinds of these fine particles may be used in combination. When two or more kinds are used in combination, they can be mixed and used at an arbitrary ratio. In this case, fine particles having different average particle diameters and different materials, for example, Aerosil 200V and R972V in a mass ratio of 0.1: 9.
It can be used in the range of 9.9 to 99.9 to 0.1. As zirconium oxide, for example, Aerosil R976 or R
Commercially available products such as 811 (manufactured by Nippon Aerosil Co., Ltd.) can also be used.

As organic fine particles, for example, silicone resin, Tospearl 103, 105, 108, 12
0,145,3120,240 (Toshiba Silicone Co., Ltd.)
Commercially available products such as manufactured products can also be used.

The primary average particle diameter of the fine particles preferably used in the present invention is measured by a transmission electron microscope (magnification: 500,000 to
The particles were observed at a magnification of 2,000,000), 100 particles were observed, and the average value was taken as the primary average particle diameter.

The apparent specific gravity of the fine particles is preferably 70 g / liter or more, more preferably 90 to 200.
g / liter, particularly preferably 100 to 200
g / liter. The larger the apparent specific gravity is, the higher the concentration of the dispersion liquid can be made, and the haze and the agglomerates are improved, which is preferable, and when the dope having a high solid content concentration is prepared as in the present invention. , Particularly preferably used.

The silicon dioxide fine particles having an average primary particle diameter of 20 nm or less and an apparent specific gravity of 70 g / L or more are, for example, 1000 obtained by mixing vaporized silicon tetrachloride and hydrogen.
It can be obtained by burning in air at ~ 1200 ° C. In the present invention, the apparent specific gravity described above was calculated by the following formula by taking a certain amount of silicon dioxide fine particles in a graduated cylinder and measuring the weight at this time.

Apparent specific gravity (g / L) = mass of silicon dioxide (g) / volume of silicon dioxide (L) As a method for preparing a dispersion of fine particles useful in the present invention and a method for adding it to a dope, For example, the following three methods can be mentioned.

<< Preparation Method A >> An organic solvent and fine particles are mixed by stirring, and then dispersed by a disperser. This is referred to as a fine particle dispersion liquid. The fine particle dispersion liquid is added to the dope liquid and stirred.

<< Preparation Method B >> The organic solvent and the fine particles are mixed by stirring, and then dispersed by a disperser. This is referred to as a fine particle dispersion liquid. Separately, a small amount of cellulose ester is added to an organic solvent and stirred and dissolved, and the fine particle dispersion is added and stirred. This is used as a fine particle added liquid, and is thoroughly mixed with the dope liquid by an in-line mixer. Here, after the addition of the following fine particle additive liquid,
An ultraviolet absorber may be added.

<< Preparation Method C >> A small amount of cellulose ester is added to an organic solvent and dissolved by stirring. Fine particles are added to this and dispersed by a disperser. This is used as a fine particle addition liquid. The fine particle added liquid is thoroughly mixed with the dope liquid by an in-line mixer.

The preparation method A is excellent in dispersibility of the silicon dioxide fine particles, and the preparation method C is excellent in that the silicon dioxide fine particles are hard to reaggregate. Above all, the above-mentioned preparation method B is a preferable preparation method which is excellent in both the dispersibility of the silicon dioxide fine particles and the difficulty of re-aggregation of the silicon dioxide fine particles.

<< Dispersion Method >> When the silicon dioxide fine particles are mixed with an organic solvent or the like and dispersed, the concentration of silicon dioxide is 5 to 5.
30 mass% is preferable, 10 to 25 mass% is more preferable, and 15 to 20 mass% is the most preferable.

The amount of the silicon dioxide fine particles added to the cellulose ester is preferably 0.01 to 0.5 parts by weight, more preferably 0.05 to 0.2 parts by weight, based on 100 parts by weight of the cellulose ester. , 0.0
Most preferably, it is 8 to 0.12 parts by mass. The larger the amount added, the better the dynamic friction coefficient of the cellulose ester film,
The smaller the added amount is, the better the haze is and the less agglomerates are.

The organic solvent used in the dispersion is preferably a lower alcohol, and examples of the lower alcohol include methanol, ethanol, propyl alcohol, isopropyl alcohol, butanol and the like. The organic solvent other than the lower alcohol is not particularly limited, but the organic solvent used when preparing the dope is preferable.

As the disperser, an ordinary disperser can be used. Dispersers are roughly divided into media dispersers and medialess dispersers. The latter is preferable for dispersing the silicon dioxide fine particles, since the haze is low. Examples of the media disperser include a ball mill, a sand mill and a dyno mill. Further, as the medialess disperser, there are an ultrasonic type, a centrifugal type, a high pressure type and the like. In the present invention, the high pressure type is preferable, and the high pressure dispersing device is preferable. The high-pressure dispersion device is a device that creates a special condition such as high shear or high-pressure state by passing a composition obtained by mixing fine particles and an organic solvent at high speed through a thin tube. In the case of processing with a high-pressure dispersion device, for example, the maximum pressure condition inside the device is preferably 9.8 MPa or more in a thin tube having a tube diameter of 1 to 2000 μm. More preferably, it is 19.6 MPa or more. At that time, it is preferable that the maximum reaching speed is 100 m / sec or more and the heat transfer speed is 420 kJ / hour or more.

The above high-pressure dispersing device is a Micro
There is an ultra-high pressure homogenizer (trade name: Microfluidizer) manufactured by fluidics Corporation or a nanomizer manufactured by Nanomizer. In addition, there is a Manton-Gaulin type high-pressure disperser, for example, a homogenizer manufactured by Izumi Food Machinery, a UHN- manufactured by Sanwa Machinery Co., Ltd. There is 01 etc.

In the present invention, when the above fine particles are contained, it is preferable that they are uniformly distributed in the thickness direction of the cellulose ester film, but it is more preferable that they are mainly distributed near the surface, for example, It is preferable that two or more kinds of dope are simultaneously cast from one die by a co-casting method, and the dope containing fine particles is arranged on the surface layer side. By doing so, the haze can be reduced and the dynamic friction coefficient can be lowered. More preferably, it is desirable to use three types of dopes to arrange the dope containing fine particles in one surface layer or both surface layers.

In order to adjust the dynamic friction coefficient of the support, a back coat layer containing fine particles may be provided on the back surface side. The coefficient of dynamic friction can be adjusted by the size and amount of the fine particles to be added, the material, and the like.

As the plasticizer preferably used in the present invention, a non-phosphate ester plasticizer is preferably used.

Examples of the non-phosphoric acid ester plasticizer include phthalic acid ester, citric acid ester, glycolic acid ester, fatty acid ester, pyromellitic acid ester and trimellitic acid ester.

Specific examples include, for example, dibenzyl phthalate, dibenzyl isophthalate, dibenzyl terephthalate, diphenyl phthalate, diphenyl isophthalate, diphenyl terephthalate, dicyclohexyl phthalate, dicyclohexyl isophthalate, dicyclohexyl terephthalate, phenyl cyclohexyl isophthalate, phenyl cyclohexyl. Examples thereof include phthalic acid-based esters such as terephthalate, phenylcyclohexyl phthalate, benzyl cyclohexyl phthalate, benzyl cyclohexyl terephthalate, and benzyl cyclohexyl isophthalate, but the present invention is not limited thereto.

Abietic acid, dehydroabietic acid, parastophosphoric acid, KE-604 (manufactured by Arakawa Kagaku), KE-8
5 (manufactured by Arakawa Chemical), Araldide EPN1139 (manufactured by Asahi Chiba Co., Ltd.), Araldide GY260 (Asahi Chiba Co., Ltd.)
(Made by Hitachi Chemical Co., Ltd.), Hirac 110H (manufactured by Hitachi Chemical Co., Ltd.), Hirac 111 (manufactured by Hitachi Chemical Co., Ltd.)
Ketone resins and the like are also preferably used.

JP-A-11-124445 and 11-9.
2574, 11-246704, 11-635.
No. 60, a non-phosphate ester plasticizer described in JP 2001-48840 A can also be used. These are preferably used alone or in combination.

The ultraviolet absorber preferably used in the present invention will be described. Specific examples of the ultraviolet absorber include, for example, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex salt compounds, and the like. However, other UV absorbers may also be used.

Specific examples include the following compounds. UV-1: 2- (2'-hydroxy-5'-methylphenyl) benzotriazole UV-2: 2- (2'-hydroxy-3 ', 5'-di-
tert-Butylphenyl) benzotriazole UV-3: 2- (2'-hydroxy-3'-tert-
Butyl-5'-methylphenyl) benzotriazole UV-4: 2- (2'-hydroxy-3 ', 5'-di-
tert-Butylphenyl) -5-chlorobenzotriazole UV-5: 2- (2'-hydroxy-3 '-(3 ",
4 ", 5", 6 "-tetrahydrophthalimidomethyl)
-5'-Methylphenyl) benzotriazole UV-6: 2,2-methylenebis (4- (1,1,3,3)
3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol) UV-7: 2- (2'-hydroxy-3'-tert-
Butyl-5'-methylphenyl) -5-chlorobenzotriazole UV-8: 2,4-dihydroxybenzophenone UV-9: 2,2'-dihydroxy-4-methoxybenzophenone UV-10: 2-hydroxy-4-methoxy -5-Sulfobenzophenone UV-11: Bis (2-methoxy-4-hydroxy-5)
-Benzoylphenylmethane) As the ultraviolet absorber, those having excellent absorption of ultraviolet rays having a wavelength of 370 nm or less and little absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display property. The ultraviolet absorption capacity of the optical thin film of the present invention is preferably 10% or less, more preferably less than 6%, particularly preferably less than 6%, with respect to light having a wavelength of 380 nm. Is less than.

The content of the ultraviolet absorber used in the optical thin film is an appropriate addition amount according to the setting of the transmittance of light having a wavelength of 380 nm.

The optical thin film and the antireflection thin film in the present invention preferably have a high refractive index layer, a medium refractive index layer and a low refractive index layer.

Titanium compounds used in the high refractive index layer and the medium refractive index layer include organic titanium compounds, titanium hydrogen compounds, titanium halides and the like. Examples of the organic titanium compounds are triethyl titanium, trimethyl titanium and triisopropyl titanium. , Tributyl titanium, tetraethyl titanium, tetraisopropyl titanium, tetrabutyl titanium,
Triethoxy titanium, trimethoxy titanium, triisopropoxy titanium, tributoxy titanium, tetraethoxy titanium, tetraisopropoxy titanium, methyldimethoxy titanium, ethyl triethoxy titanium, methyl triisopropoxy titanium, tetradimethylamino titanium, dimethyl titanium diacetate Acetonate, ethyltitanium triacetoacetonate, etc., examples of titanium hydrogen compounds include monotitanium hydrogen compounds, dititanium hydrogen compounds, etc., and examples of titanium halides include titanium trichloride, titanium tetrachloride, etc. Can be preferably used in.

The silicon compound used for the low refractive index layer may be an organic silicon compound, a silicon hydrogen compound, a silicon halide compound, or the like, and the organic silicon compound may be tetraethylsilane, tetramethylsilane, or tetramethylsilane. Isopropylsilane, tetrabutylsilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, dimethyldimethoxysilane, diethyldiethoxysilane, diethylsilanediacetoacetonate, methyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane As the silicon hydrogen compound, tetrahydrogenated silane, hexahydrogenated disilane and the like can be mentioned, and any of them can be preferably used in the present invention.

The preferred antireflection optical thin film of the present invention may be formed by directly forming the metal oxide layer on the support, or may be formed on at least one other layer. In the present invention, examples of the other layer include a hard coat layer and the like, and these layers are preferably actinic ray curable resin layers that are cured by actinic rays such as ultraviolet rays. By forming a metal oxide layer on such a resin layer cured by ultraviolet rays, an antireflection optical thin film having excellent scratch resistance can be obtained.

The actinic radiation curable resin layer such as the hard coat layer is
The resin layer is preferably formed by polymerizing a component containing an ethylenically unsaturated monomer.

Here, the actinic ray curable resin layer means a layer whose main component is a resin which is cured by a crosslinking reaction or the like by irradiation with actinic rays such as ultraviolet rays and electron beams.

Typical examples of the actinic ray curable resin include an ultraviolet curable resin and an electron beam curable resin, but a resin which is cured by irradiation with an actinic ray other than an ultraviolet ray or an electron beam may be used. As the ultraviolet curable resin, for example,
Examples thereof include UV-curable acrylic urethane-based resin, UV-curable polyester acrylate-based resin, UV-curable epoxy acrylate-based resin, UV-curable polyol acrylate-based resin, and UV-curable epoxy resin.

The ultraviolet curable acrylic urethane resin is
In general, a product obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer further includes 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter, when it is described as acrylate, methacrylate is included), 2 −
It can be easily obtained by reacting an acrylate-based monomer having a hydroxyl group such as hydroxypropyl acrylate (for example, JP-A-59-15111).
(See No. 0).

The UV-curable polyester acrylate resin can generally be easily obtained by reacting a polyester polyol with 2-hydroxyethyl acrylate or a 2-hydroxy acrylate monomer (for example, JP-A-59-151112). (See the description of).

As a specific example of the ultraviolet-curable epoxy acrylate resin, an epoxy acrylate as an oligomer, to which a reactive diluent and a photoreaction initiator are added and reacted (for example, Kaihei 1
-105738). As the photoreaction initiator, one or more selected from benzoin derivatives, oxime ketone derivatives, benzophenone derivatives, thioxanthone derivatives and the like can be used.

Specific examples of the UV-curable polyol acrylate resin include trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate and alkyl-modified dipenta. Examples thereof include erythritol pentaacrylate.

These resins are usually used together with known photosensitizers. The above photoreaction initiator can also be used as a photosensitizer. Specifically, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone,
Examples thereof include α-amyloxime ester, thioxanthone, and derivatives thereof. When using an epoxy acrylate-based photoreactive agent, n-butylamine,
Sensitizers such as triethylamine and tri-n-butylphosphine can be used. The photoreaction initiator or photosensitizer contained in the UV-curable resin composition excluding the solvent component that volatilizes after coating and drying can be added in an amount of usually 1 to 10% by mass of the composition. Mass% is preferred.

The actinic radiation curable resin layer preferably used in the present invention can be applied by a known method.

As the light source for forming the cured film layer by the photocuring reaction of the actinic ray curable resin, any light source which emits ultraviolet rays can be used.

For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a super high pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, etc. can be used. The irradiation conditions vary depending on individual lamps, but the amount of light irradiated may if 20~10000mJ / cm ^2, preferably from 50~2000mJ / cm ^2. It can be used by using a sensitizer having an absorption maximum in the near-ultraviolet region to the visible light region.

As the solvent for applying the actinic radiation curable resin layer, for example, hydrocarbons, alcohols, ketones,
It can be appropriately selected from esters, glycol ethers and other solvents, or can be used by mixing them.
Preferably, propylene glycol mono (having 1 to 4 carbon atoms
Alkyl group) alkyl ether of propylene glycol mono (alkyl group having 1 to 4 carbon atoms) alkyl ether ester is 5% by mass or more, more preferably 5 to 8%.
A solvent containing 0% by mass or more is used.

As a method for applying the ultraviolet-curable resin composition coating solution, known methods such as a gravure coater, a spinner coater, a wire bar coater, a roll coater, a reverse coater, an extrusion coater and an air doctor coater can be used. The coating amount is usually 0.1 to 30 μm in terms of wet film thickness, preferably 0.5 to 1
It is 5 μm. The coating speed is preferably 10 to 60 m / min.

The UV-curable resin composition is coated and dried and then irradiated with UV rays from a light source. The irradiation time is preferably 0.5 seconds to 5 minutes. Seconds to 2 minutes are more preferable.

Inorganic or organic fine particles are preferably added to the thus obtained cured film layer in order to prevent blocking and enhance scratch resistance.

For example, as the inorganic fine particles, silicon oxide,
Examples thereof include titanium oxide, aluminum oxide, tin oxide, zinc oxide, calcium carbonate, barium sulfate, talc, kaolin, calcium sulfate, and the like, and as the organic fine particles, polymethacrylic acid methyl acrylate resin powder, acrylic styrene resin Powder, polymethylmethacrylate resin powder, silicon resin powder, polystyrene resin powder, polycarbonate resin powder, benzoguanamine resin powder, melamine resin powder, polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin Powders, polyfluorinated ethylene-based resin powders and the like can be mentioned, which can be added to the ultraviolet curable resin composition. The average particle size of these fine particle powders is preferably 0.005 to 1 μm, and 0.0
Particularly preferably, it is 1 to 0.1 μm.

The ratio of the ultraviolet curable resin composition to the fine particle powder is 0.1 to 10 relative to 100 parts by mass of the resin composition.
It is desirable to mix them in such an amount that they will be part by mass.

In the present invention, when the optical thin film of the present invention is provided on the surface of the support as described above, it is preferable to provide it so that the deviation of the average film thickness is ± 10%.
It is more preferably within ± 5%, and most preferably ± 1.
It is preferable to provide it so as to be within%.

As the antioxidant, hindered phenol compounds are preferably used.
6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4)
-Hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,
6-hexanediol-bis [3- (3,5-di-t-
Butyl-4-hydroxyphenyl) propionate],
2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3
5-triazine, 2,2-thio-diethylenebis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate], octadecyl-3- (3,5-di-
t-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5-di-t-
Butyl-4-hydroxy-hydrocinnamamide), 1,
3,5-Trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, Tris- (3,5-di-t-butyl-4-hydroxybenzyl)- Isocyanurate and the like can be mentioned. In particular, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5
-Methyl-4-hydroxyphenyl) propionate]
Is preferred. Further, for example, N, N'-bis [3- (3,3
5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and other hydrazine-based metal deactivators and tris (2,4-di-t-butylphenyl) phosphite and other phosphorus-based processing stabilizers You may. The addition amount of these compounds is preferably 1 ppm to 1.0% by mass ratio with respect to the cellulose ester, and is 10 to 1000 p.
pm is more preferred.

These antioxidants are also called deterioration inhibitors, and when the liquid crystal image display device is placed in a high-humidity and high-temperature state, the cellulose ester film may be deteriorated. Since the cellulose ester film has a role of delaying or preventing decomposition due to the residual solvent amount of halogen, phosphoric acid of a phosphoric acid plasticizer, or the like, it is preferably contained in the cellulose ester film.

[0133]

EXAMPLES The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1 << Preparation of Dope Liquid >> (Preparation of Silicon Oxide Dispersion Liquid) Aerosil 200V (manufactured by Nippon Aerosil Co., Ltd.) 1 kg Ethanol 9 kg After stirring and mixing the above materials with a dissolver for 30 minutes, Manton-Gaulin type high pressure dispersion Dispersion was performed using the device.

(Preparation of Additive Solution A) Cellulose acetate propionate (acetyl substitution degree: 1.9, propionyl group substitution degree: 0.7) 4 kg Methylene chloride 76 kg Tinuvin 326 (manufactured by Ciba Specialty Chemicals) 3 kg Tinuvin 109 (Ciba) Specialty Chemicals Co., Ltd.) 4 kg Tinuvin 171 (Ciba Specialty Chemicals Co., Ltd.) 4 kg The above materials are placed in a closed container, heated and stirred,
It was completely dissolved and filtered. To this, 9 kg of the above silicon oxide dispersion was added with stirring, and the mixture was further stirred for 30 minutes and then filtered to prepare an addition liquid A.

(Preparation of Dope A) Compound 1 18 kg Methylene chloride 320 kg Ethanol 60 kg Cellulose acetate propionate (acetyl substitution degree: 1.9, propionyl group substitution degree: 0.7) 110 kg A closed container while stirring the above materials in order. It was put into a vessel and completely dissolved and mixed while heating and stirring. The dope was cooled to a temperature at which it was cast, allowed to stand overnight, and subjected to a defoaming operation. Then, the solution was added to Azumi Filter Paper No. Filtered using 244. Furthermore, the additive solution A per 100 kg of the solution
Was added at a rate of 2 kg, thoroughly mixed with an in-line mixer (Toray static type in-tube mixer Hi-Mixer, SWJ), and filtered to prepare a dope (A).

[0137]

[Chemical 1]

<< Preparation of Transparent Support >> After filtering the dope solution A, a dope temperature of 35.degree.
It was evenly cast on the stainless steel band support. After drying on the support for 90 seconds, the web formed on the stainless band support was peeled off.

After the web was peeled from the stainless band support and dried while being conveyed by a roll in a drying zone of 80 ° C., when the residual solvent amount in the web was 20% by mass or less, a biaxial stretching tenter was used. 1.07 times in TD direction (width direction) and 1.01 in MD direction (film formation direction)
After being double-stretched and dried at 90 ° C., the width grip was released, and further drying was completed in a drying zone at 120 ° C. while being conveyed by rolls to prepare a transparent support having a film thickness of 60 μm.

The film width was 1300 mm and the winding length was 2000 m. The amount of residual solvent in the film after winding was less than 0.1% by mass.

Here, the MD direction indicates the film forming direction of the film during the casting film formation, and the TD direction indicates the width direction of the film during the casting film formation.

The following hard coat layer composition (1) was coated on one surface of the above transparent support with the following hard coat layer composition (1) using an extrusion die at a set room temperature of 24 ° C. and dried at 120 ° C. Next, the coating layer was cured by irradiating with ultraviolet rays to prepare a transparent support having a hard coat layer having a thickness of 3.0 μm. The refractive index of the hard coat layer was 1.50.

[0143]   <Hard coat layer composition (1)>   Dipentaerythritol hexaacrylate monomer 60 parts by mass   Dipentaerythritol hexaacrylate dimer 20 parts by mass   Dipentaerythritol hexaacrylate trimer or more components                                                           20 parts by mass   2 parts by weight of diethoxybenzophenone (UV photoinitiator)   Aerosil R-972V (manufactured by Nippon Aerosil Co., Ltd.) 1 part by mass   Methyl ethyl ketone 50 parts by mass   50 parts by mass of ethyl acetate   Isopropyl alcohol 50 parts by mass The above composition was ultrasonically dispersed while stirring.

<< Preparation of Multi-Layer Antireflection Optical Thin Film >><Coating Liquid for Medium Refractive Index Layer> Tetra (n) butoxytitanium 250 parts by mass Terminal reactive dimethyl silicone oil (L-9000 manufactured by Nippon Unicar Co., Ltd.) 0.48 parts by mass Aminopropyltrimethoxysilane (KBE903 manufactured by Shin-Etsu Chemical Co., Ltd.) 22 parts by mass UV curable epoxy resin (KR500 manufactured by Asahi Denka Co., Ltd.) 21 parts by mass propylene glycol monomethyl ether 4900 parts by mass isopropyl alcohol 4840 parts by mass <Coating liquid for high refractive index layer > Tetra (n) butoxy titanium 310 mass parts Terminal reactive dimethyl silicone oil (L-9000 manufactured by Nippon Unicar Co., Ltd.) 0.4 mass part Aminopropyltrimethoxysilane (KBE903 manufactured by Shin-Etsu Chemical Co., Ltd.) 4.8 mass parts UV curability Epoxy resin (KR500 manufactured by Asahi Denka Co., Ltd.) 4.6 parts by mass Propylene glycol monomethyl ether 4900 parts by mass Isopropyl alcohol 4800 parts by mass <Coating liquid for low refractive index layer> Tetraethoxysilane hydrolyzate A 1020 parts by mass Terminal reactive dimethyl silicone oil (L-9000 manufactured by Unicar Japan) ) 0.42 parts by mass Propylene glycol monomethyl ether 2700 parts by mass Isopropyl alcohol 6300 parts by mass On the transparent support having the hard coat layer, a medium refractive index layer, a high refractive index layer, and a low refractive index layer are sequentially coated on the hard coat layer. Was coated using a die and dried at 120 ° C., and then the coating layer was cured by irradiation with ultraviolet rays to form a laminated film. The flow rate condition was controlled while measuring the film thickness of the formed layer online. In this way, the medium refractive layer (thickness: 0.0
75 μm), a high refraction layer (thickness: 0.070 μm) and a low refraction index layer (thickness: 0.093 μm) were formed to prepare a multilayer antireflection film.

The refractive index and the film thickness of each layer are obtained from the measurement results of the spectral reflectance of a spectrophotometer for a sample in which each layer is applied alone. Using spectrophotometer U-4000 (Hitachi), after roughening the back surface of the sample, perform light absorption treatment with a black spray to prevent reflection of light on the back surface and correct it at 5 degrees. Visible light range (400-70
0 nm) reflectance measurement is performed.

The refractive index of each of the completed layers was a medium refractive layer 1.65, a high refractive layer 1.90 and a low refractive layer 1.45.

[Evaluation Criteria for Width Distribution] The distribution was evaluated by the variation (maximum value-minimum value) of 10 points of the reflectance (1300 mm width) of 440 nm. 440 nm corresponds to the rising timing of the reflection spectrum on the lower side of visible light, and is the part where sensitivity is most severe. Width uniformity ○ Less than ± 1% △ Less than ± 2%: Lower limit of practicable range × ± 2% or more: Not practical

Difference between coater chamber temperature and die heat retention temperature ΔT
(Coater room temperature-die heat retention temperature)

[0149]

[Table 1]

As shown in Table 1, a high quality optical thin film having an excellent width distribution was obtained. Example 2 A laminated antireflection film was prepared in the same manner as in Example 1. At this time, the set room temperature was changed as follows, and the distribution and the generation state of the streaks were evaluated.

[Evaluation Criteria for Streaks] A black acrylic plate was attached to the back surface of the antireflection thin film, and the streaks were visually evaluated.

○ No black streaks in black-painted products △ Vaguely visible in black-painted products, invisible in transparent film × Clearly visible in black-painted products and transparent products

[0153]

[Table 2]

As shown in Table 2, the total temperature is 21 to 26.
By adjusting the temperature to 0 ° C., it is possible to obtain an optical thin film in which the generation of streaks is prevented and the distribution is secured.

Example 3 A laminated antireflection film was prepared in the same manner as in Example 1. At this time, the set room temperature was changed as follows, and the width distribution and the occurrence of streaks were evaluated. Room temperature 28 ° C Die heat retention temperature and liquid supply temperature difference: ΔT '(die heat retention temperature-liquid temperature difference)

[0156]

[Table 3]

As shown in Table 3, the total temperature is 21 to 26.
By adjusting the temperature to 0 ° C., it is possible to obtain an optical thin film in which the generation of streaks is prevented and the distribution is secured.

Example 4 A laminated antireflection film was prepared in the same manner as in Example 1. At this time, a 6-element static mixer manufactured by Noritake Co., Ltd. was installed at the entrance of the die. In addition, a static mixer with a heat retaining function using jacket warm water was also evaluated. Die insulation temperature 25 ℃, room temperature, 22 ℃ (= liquid temperature)

[0159]

[Table 4]

The improvement in distribution as shown in Table 4 means that
It can be estimated that the temperature distribution of the entire pipe is made uniform by the static mixer.

Example 5 A laminated antireflection film was prepared in the same manner as in Example 1. At this time, the distribution width was evaluated by adjusting the variation width using a die having an adjusting mechanism for the exit slit gap of the die. Room temperature 28 ℃

[0162]

[Table 5]

As shown in Table 5, it is possible to obtain an optical thin film whose performance is ensured when the variation width of the slit gap is 2 μm or less.

Example 6 A laminated antireflection film was prepared in the same manner as in Example 1. At this time, dies having different lip lengths were produced and the occurrence of streaks was evaluated. Room temperature 28 ℃

[0165]

[Table 6]

As shown in Table 6, the total temperature is set to 21 to 26.
By adjusting the temperature to ℃, it is possible to obtain an optical thin film in which generation of streaks is prevented.

Example 7 A laminated antireflection film was prepared in the same manner as in Example 1. At this time, the coating gap and the reduced pressure value were changed as follows, and the distribution and the generation state of streaks were evaluated.

[0168]

[Table 7]

By setting the coating gap and the reduced pressure value as shown in Table 7, it is possible to obtain an optical thin film which prevents the generation of streaks and secures the distribution.

Example 8 A laminated antireflection film was prepared in the same manner as in Example 1. At this time, the solvent ratio of the liquid was changed to the ratio of (PGME / IPA) to change the viscosity dependence. Room temperature 28 ℃

[0171]

[Table 8]

As shown in Table 8, by setting the temperature dependence of the viscosity of the coating liquid to -0.5% to -2% or less, an optical thin film with a secured distribution can be obtained.

Example 9 A laminated antireflection film was prepared in the same manner as in Example 1. At this time, the finished solid film thickness was kept constant, and the coating was carried out while changing the concentration of the coating liquid and the wet film thickness at the time of coating.

Room temperature 28 ° C

[0175]

[Table 9]

As shown in Table 9, the coating film thickness is 5 to 13 μm.
It is possible to obtain an optical thin film in which the distribution is ensured while preventing the generation of streaks by adjusting to 1.

[0177]

According to the present invention, the width distribution of the width is excellent,
It was possible to provide a method for producing a uniform optical thin film having no streak defect, particularly an antireflection film having a uniform reflection spectrum on the width.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a coating section of the present invention.

FIG. 2 is a graph showing the temperature dependence of viscosity.

[Explanation of symbols]

1, 1'Lip 2, 2'Lip tip parallel to backup roll 4 Backup roll 5 Support 7 Slit

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2K009 AA06 BB24 BB28 CC02 CC09                       CC14 CC26 CC42 DD02 DD05                       DD06 DD09                 4F202 AG01 AH73 AR06 AR12 CA07                       CB01 CN01                 4F205 AG01 AH73 AM26 AM28 AR06                       AR17 GA07 GB02 GC07 GN19                       GN21 GN28

Claims (12)

[Claims] 1. A method for producing an optical thin film obtained by coating and drying a support on a support using a die, wherein the die has a heat retaining function, and the difference between the die heat retaining temperature and the coater chamber temperature is −2 ° C. to +.
The method for producing an optical thin film is characterized in that the temperature is 2 ° C. 2. The method for producing an optical thin film according to claim 1, wherein the die keeping temperature range is 21 ° C. to 26 ° C. 3. A method for producing an optical thin film obtained by coating and drying a support on a support using a die, wherein the die and the liquid supply pipe have a heat retention function, and the difference between the die heat retention temperature and the liquid supply temperature is −.
2 ° C to + 2 ° C and the die heat retention temperature range is 21 ° C to
The method for producing an optical thin film, wherein the temperature is 26 ° C. 4. A method for producing an optical thin film, characterized in that a static mixer is used for a pipe at the die inlet in the production of an optical thin film obtained by coating and drying a support on a support using a die. 5. A method for producing an optical thin film obtained by coating and drying a support on a support using a die, wherein a jacket hot water heat exchanger and a static mixer are used for piping of the die inlet. Thin film manufacturing method. 6. The accuracy of the slit exit of the die used in the method for producing an optical thin film is 1 m as a width distribution of the slit gap.
Variation range (maximum value of 10-point average-minimum value)
Is 2 μm or less, a method for producing an optical thin film. 7. The length of the portion of the die lip parallel to the backup roll used in the method for producing an optical thin film is upstream,
A method for manufacturing an optical thin film, which is an extrusion coater having a downstream diameter of 700 μm to 1300 μm. 8. The distance (coating gap) from the lip of the extrusion coater to the support using reduced pressure used in the method for producing an optical thin film is 50 μm to 150 μm, and the reduced pressure is −200 to −400 Pa. A method for producing a characteristic optical thin film. 9. The temperature dependence of the viscosity of the coating liquid is -2% /
A method for producing an optical thin film, which comprises using a coating liquid of not less than 0 ° C and not more than -0.5% / ° C. 10. The method for producing an optical thin film according to claim 1, wherein the coating film thickness is 5 μm to 13 μm. 11. An optical thin film manufactured by the manufacturing method according to any one of claims 1 to 10. 12. The optical thin film according to claim 11, wherein the optical thin film is an antireflection film.