JP5100226B2 - Antireflection film manufacturing method and antireflection film - Google Patents

Description

  The present invention relates to a method for producing an antireflection film and an antireflection film, and is particularly excellent in scratch resistance and adhesion at the interface of each layer, and is less reflective in appearance surface quality due to elution of additive components from the film surface. The present invention relates to an antireflection film manufacturing method and an antireflection film.

  Flat image display devices (FPD) such as cathode ray tube display (CRT), plasma display (PDP), electroluminescence display (ELD) and liquid crystal display (LCD) have improved visibility and scratch resistance. In order to improve, an optical functional film such as an antireflection film, an antiglare film, or a surface protective film is used as the outermost layer.

  The above optical functional films are often exposed directly to human eyes, and the optical functionality that is used due to the recent increase in screen size, brightness, resolution, and price. The film is required to have extremely strict appearance quality (no point defects, unevenness, dirt, etc.) and physical durability quality (excellent scratch resistance, antifouling property, etc.). In particular, when the surface of the display is scratched, the antireflection film becomes a permanent display defect, and the appearance quality of the image display device is remarkably deteriorated. Therefore, scratch resistance is important.

  The optical functional layer of the antireflection film is formed by repeating the application / drying of the functional material forming material solution on the base film, particularly the application / drying of the functional material forming material solution containing an organic solvent, a plurality of times. There are many. In the process of manufacturing an optical film provided with an optical functional layer by such a coating process, appearance failure (particularly unevenness failure) due to disturbance of the coating liquid immediately after coating, or disturbance of the coating thickness of the optical functional layer due to uneven drying. Is likely to occur.

  For this reason, in the coating solution, there is a method of adding an additive such as a fluorine-based compound or a silicone-based compound having a surface active action to the coating solution in order to improve coating property, uniform drying, and impart high-speed coating suitability. It has been proposed (see Patent Document 1). In addition, a method of controlling the drying speed during initial drying and performing non-contact conveyance is also performed. (See Patent Document 2).

  On the other hand, as a method for imparting scratch resistance, when a low refractive index layer located on the outermost surface is formed, a coating liquid mainly composed of an ionizing radiation curable resin composition having fine particles is applied, and this is applied to ultraviolet rays. A method of curing with an electron beam or heat is known (Patent Document 3).

Further, the antireflection film is formed by laminating a plurality of optical functional layers and physical functional layers, and in order to improve interlayer adhesion, the reactive functional group of the curable resin of the coated layer is in a half-cured state. (Patent Document 4).
JP 2005-257786 A JP 2006-334561 A JP-A-9-145903 JP 2003-311911 A

  Using the methods described in Patent Documents 1 to 4, an additive having a surface active action or the like is added to the coating solution for the purpose of improving coating properties, drying uniformity, and imparting high-speed coating suitability. Further, in order to improve interlayer adhesion with the coating layer (upper layer), an antireflection film is produced using the coated layer as a half cure. Then, after applying and drying the coating layer, heat curing treatment, ionizing radiation curing treatment, when imparting scratch resistance to the coating layer, white powder failure due to the substance eluted from the coating layer occurs on the coating layer surface, There is a problem of deteriorating appearance quality, and it is difficult to achieve both scratch resistance and appearance quality.

  The inventors of the present invention have added a fluorine-based compound or a silicone-based substance in which a white powder-like substance that causes a decrease in appearance quality is added to improve coating properties, dry uniformization, and impart high-speed coating suitability included in the coating. It was confirmed that the compound was an additive component having a surfactant activity of the compound. From this, the white powder failure is caused by heat shrinkage caused by curing the ionizing radiation curable resin composition with ultraviolet rays, electron beams, or heat in order to impart scratch resistance to the low refractive index layer which is the outermost layer. This is thought to be due to the elution (crying out) of the added components.

  However, an additive component having a surfactant activity of a fluorine-based compound or a silicone-based compound is an essential component for improving coating properties, uniforming drying, and imparting high-speed coating suitability, and it is not preferable to remove them. In addition, making the coating layer a half-cure is important for imparting scratch resistance in order to improve the interlayer adhesion between the coating layer and the coating layer.

  On the other hand, from the viewpoint of productivity, it is desired to shorten the heating (curing) drying time for imparting scratch resistance.

  The present invention has been made in view of such circumstances, and at the same time, provides both scratch resistance and appearance quality, produces an antireflection film with good quality and yield, and imparts scratch resistance from the viewpoint of improving productivity. It is an object of the present invention to provide an antireflection film manufacturing method and an antireflection film capable of shortening the heating (curing) drying time.

According to a first aspect of the present invention, in order to achieve the above object, a support, at least one optical function layer disposed on the support, and the optical function layer are disposed. In a method for producing an antireflection film having a low refractive index layer having a refractive index lower than that of a functional layer, a coating layer is formed by applying a liquid for forming the low refractive index layer on the surface of the optical functional layer. A coating step, a drying step for promoting the drying of the coating layer, and a curing step for thermally curing the coating layer whose drying has been accelerated to form a low refractive index layer. A first curing step of curing with a drying air at a first temperature; and a second curing step of curing the coating layer with a drying air at a second temperature lower than the first temperature after the first curing step . and curing step, the coated layer after the second curing step than the second temperature There a third curing step of curing the coating layer at a dry air of the third temperature, have a, the first temperature is 120 ° C. or less 100 ° C. or higher, the second temperature is 85 ° C. or higher 100 ° C. or less And the third temperature is 100 ° C. or higher and 120 ° C. or lower .
In addition, by adjusting the first temperature, the second temperature, and the third temperature to the above ranges, it is possible to provide a manufacturing method that suppresses the precipitation of a white powdery substance and improves the curing rate.

  It is known that a white powdery substance is generated by curing at a high curing temperature in the initial stage of curing. However, since the coating layer contains a large amount of solvent in the initial stage of this initial stage, heat is used for volatilization of the solvent without causing precipitation of a white powdery substance even if curing is performed at a high temperature. Can be cured. Therefore, in the present invention, in the first curing process, which is the initial stage of the curing process, the temperature of the drying air is cured with the drying air having the first temperature higher than the second temperature. Thereby, since curing is performed at a higher temperature than before, the curing and drying time can be shortened.

  Next, in the second curing step, the temperature of the drying air was set lower than that in the first curing step. When the amount of solvent in the coating layer is reduced by the first curing step, a white powdery substance is precipitated by curing of the coating layer. Therefore, in the second curing step, by reducing the temperature, Precipitation of substances can be prevented. Further, in the second curing step, by reducing the temperature, it is possible to prevent the curing compound from volatilizing from the coating layer in which the amount of the solvent is reduced, so that the crosslinking density of the antireflection film is reduced. Can be suppressed.

  Further, in the third curing step, the temperature of the drying air is cured at a third temperature higher than the second temperature. Since the coating layer is substantially cured by the second curing step, the coating layer is cured without precipitation of a white powdery substance even when the film surface temperature is increased in the third curing step. be able to. Further, in the third curing step, by raising the third temperature, the curing reaction of the coating layer can be sufficiently promoted, and a very high hardness layer can be obtained.

  Further, by setting the temperature distribution of the drying air in the curing step to a high first temperature, a low second temperature, and a high third temperature, even if the coating layer before curing is in a half-cured state, The coating layer can be cured without precipitation of a powdery substance.

  Therefore, as a result, it is possible to form an antireflection film having no appearance failure and excellent scratch resistance.

  A second aspect of the present invention is characterized in that, in the first aspect, the support is a transparent support having a Re value of 0 to 200 nm.

  According to the second aspect, by setting the retardation value of the support within the above range, it can be suitably used as an antireflection film of an image display device.

  According to a third aspect of the present invention, in the first or second aspect, the first curing step is a constant rate drying period of the coating film, and the second curing step is a decreasing rate drying period of the coating film, The curing step and the second curing step are partitioned at the position of the drying change point from the constant rate drying period to the decreasing rate drying period.

  The third aspect defines the sections of the first curing step and the second curing step. By setting the first curing step to a constant rate drying period, even if the temperature of the drying air is high, all the heat is used for solvent evaporation of the coating layer. Thus, it is possible to form an antireflection film free from precipitation of the above substances and having no appearance failure.

  However, since most of the heat is used for curing the coating layer in the decreasing rate drying period when the solvent in the coating film is low, the temperature of the coating film becomes high and the curing proceeds rapidly, so that the white powder form May be deposited.

  Therefore, in the second curing step, the temperature of the drying air is lowered at the drying change point where the constant rate drying period shifts to the decreasing rate drying period. Thereby, since hardening progresses slowly, it can harden | cure an application layer, without depositing a white powder-like substance.

  A fourth aspect of the present invention is characterized in that, in the third aspect, the drying change point is a range in which the solid content in the coating film is 60 to 80%.

  Claim 4 defines the position of the drying change point which is a change point between the first curing step and the second curing step, and the position where the solid content in the coating film is 60 to 80% by mass; It is preferable to do. Therefore, by measuring the solid content in the coating film, it is possible to know at which position in the curing process the first curing process and the second curing process should be changed.

A fifth aspect of the present invention is the composition for forming an optical functional layer according to any one of the first to fourth aspects, wherein the optical functional layer contains at least one selected from a fluorine-based compound having a surface active action and a silicone-based compound. It is characterized by that.

According to the fifth aspect , an optical functional layer having excellent antifouling properties and slipperiness can be formed by containing a fluorine-based compound or a silicone-based compound having a surface activity in the optical functional layer.

A sixth aspect of the present invention is characterized in that in the first to fifth aspects, the low refractive index layer contains a curing compound containing at least one monomer having two or more crosslinkable reactive groups.

According to claim 6 , a compound containing at least one monomer having two or more crosslinkable reactive groups as the curing compound, in particular, can produce an optical compensation sheet having both good adhesion and good surface condition. Because.

A seventh aspect is characterized in that, in the sixth aspect , the monomer having two or more crosslinkable reactive groups is an aldehyde compound containing two or more aldehyde groups.

According to the seventh aspect , since the monomer having two or more cross-linking reactive groups is an aldehyde compound having two or more aldehyde groups, the adhesion between the support and the coating film can be improved.

In order to achieve the above object, an eighth aspect provides an antireflection film manufactured by the manufacturing method according to any one of the first to seventh aspects.

8. are the antireflection film produced by the production method of the antireflective film according to claims 1 7, excellent scratch resistance, an excellent antireflection film appearance quality.

A ninth aspect is characterized in that, in the eighth aspect , the optical functional layer is an anti-glare layer.

A tenth aspect is characterized in that, in the eighth or ninth aspect , a refractive index of the optical functional layer is 1.58 or more and 2.00 or less.

An eleventh aspect is characterized in that, in the eighth to tenth aspects, a refractive index of the low refractive index layer is 1.31 or more and 1.45 or less.

According to the eighth to eleventh aspects, reflection from the support can be efficiently prevented by using the optical function layer as an antiglare property-imparting layer. Further, the reflectance can be reduced by setting the refractive index within the above range.

  According to the present invention, by reducing the temperature of the drying air in the second curing step in which the curing of the coating layer is accelerated, the adhesion between the coating layer and the coating layer is maintained and the scratch resistance is excellent, and the appearance quality is improved. Can be provided. Further, by raising the temperature of the drying air in the first curing step, the heat curing time can be shortened, so that productivity can be improved. Further, in the third curing step, by raising the temperature of the drying air, the curing reaction of the coating layer can be sufficiently promoted, and a very hard layer can be obtained. Therefore, as a result, it is possible to form an antireflection film having no appearance failure and excellent scratch resistance.

  Hereinafter, the manufacturing method of the antireflection film of the present invention and the antireflection film manufactured by the manufacturing method will be described with reference to embodiments. In addition, the form shown here is an example which concerns on this invention, and does not limit this invention. FIG. 1 shows a schematic diagram of a film production apparatus 1 used in the present embodiment.

  The film manufacturing apparatus 1 includes a base 70 for an antireflection film to be formed, that is, a delivery device 70 for feeding out the base film 2, a coating apparatus 10 for forming a coating layer by coating a liquid on the surface of the base film 2, A plurality of pass rollers 31, a drying device 30 for drying the coating layer, a front chamber 42 a, a middle chamber 42 b, and a rear chamber 42 c partitioned by a partition plate 41, for thermosetting the coating layer , A heating device 40, an ultraviolet lamp 50 for making the antireflection film 3 by sufficiently irradiating the coating layer with ultraviolet rays and curing the coating layer, and a winder 60 for winding the antireflection film 3 are provided. ing. In addition, the film manufacturing apparatus 1 includes a plurality of transport rollers 80 and a dust remover 90.

  The coating apparatus 10 includes a micro gravure roller 11 on which a gravure pattern is engraved and a tank (not shown) in which a coating liquid is placed below the conveyance path of the base film 2. The micro gravure roller 11 is a member for applying a coating liquid to a desired surface of the base film 2. Further, the tank is located below the micro gravure roller 11 and is disposed at a position where the surface of the micro gravure roller 11 comes into contact with the coating liquid, so that the surface of the micro gravure roller 11 contacts the coating liquid in the tank. By doing so, the coating liquid can be supplied to the gravure pattern. Here, since the excess coating liquid is removed by a doctor blade (not shown), the coating liquid supplied to the gravure pattern can be adjusted to an appropriate amount.

  The drying device 30 includes a transfer chamber 32 and an exhaust chamber 33 that are partitioned by an air conditioning plate 34. The air-conditioning plate 34 is a metal plate provided with a plurality of openings, and provides good ventilation between both chambers while partitioning the transfer chamber 32 and the exhaust chamber 33. The aperture ratio and material of the air conditioning plate 34 are not particularly limited, but a wire mesh or punching metal with an aperture ratio of 50% or less is preferable, and an aperture ratio is more preferably 20 to 40%. In the present embodiment, a wire mesh with 300 mesh and an aperture ratio of 30% is used. In addition, it is preferable to provide the air conditioning plate 34 so that the space | interval of the air conditioning plate 34 and the coating layer surface of the base film 2 may be about 10 mm.

  The transfer chamber 32 is provided with a plurality of pass rollers 31 for transferring the base film 2 while supporting it. In addition, it is preferable that each pass roller 31 is a form which can be attached or detached and can be easily attached or detached. For example, when the residual solvent amount of the liquid applied on the base film 2 is 20% or more and 45% or less, if the pass roller 31 is removed and conveyed to the base film 2 in a non-contact manner, the flatness is lowered. The base film 2 can be conveyed without making it.

  The exhaust chamber 33 is disposed in the width direction of the base film 2 and is opposed to the exhaust chamber 33. The exhaust pipe 33 exhausts air in the exhaust chamber 33 and a supply air for feeding new air into the exhaust chamber 33. An air pipe (both not shown) is attached. In the exhaust chamber 33, air is exhausted into the exhaust chamber 33 by the exhaust pipe, and dry air heated to a desired temperature is sent into the exhaust chamber 33 by the air supply pipe. Is adjusted accordingly. Thereby, drying of the coating layer on the base film 2 conveyed in the conveyance chamber 32 can be promoted. The air supplied from the air supply pipe may be a gas other than air and is not particularly limited.

  In the heating device 40, inside the front chamber 42a, the middle chamber 42b, and the rear chamber 42c partitioned by the partition plates 41a and 41b, an air supply duct 43a that is a temperature control means for adjusting the internal temperature of each chamber, 43b and 43c are respectively installed. The partition plates 41a and 41b are not particularly limited in shape and material, but are preferably formed of a material having low thermal conductivity. Also, the temperature control means is not particularly limited, and examples thereof include a heater that can arbitrarily control the heating temperature. Further, the film manufacturing apparatus 1 is appropriately provided with a transport roller 80 for transporting the base film 2 while supporting it. In addition, the installation location and the number of the transport rollers 80 are not particularly limited, and can be selected as necessary.

  Next, a method for producing an optical film using the film production apparatus 1 as described above will be described.

  FIG. 2A shows a cross-sectional view of the antireflection film 3. The antireflection film 3 has a structure in which a low refractive index layer 24 is formed on the base film 2. First, the structure of the base film 2 serving as the base of the antireflection film 3 to be formed will be described. The base film 2 used in the present embodiment includes a transparent support 21, a first layer 22 disposed in contact with the support 21, and a plurality of translucent fine particles 25. The material and structure of the base film 2 are not particularly limited, and it is preferable to use a commercially available polymer film or the like that is provided by coating a desired optical functional layer on the support. Can do. Although the preferred range of the retardation value (Re value) of the support varies depending on the liquid crystal display device in which the antireflection film is used and the method of use thereof, the Re value is usually a transparent support having a thickness of 0 to 200 nm. preferable. By setting the Re value of the support within the above range, it can be suitably used as an antireflection film for an image display device. Also, the types of the first layer 22 and the second layer 23 are not particularly limited, but in the present embodiment, in order to obtain the antireflection film 3 having excellent optical characteristics, the first layer 22 is a hard coat layer. The second layer 23 is an antiglare hard coat layer. The translucent fine particles 25 will be described in detail later.

  First, the base film 2 is appropriately sent out from the delivery device 70, and the delivered base film 2 is blown from the dust remover 90 toward the surface while being conveyed while being supported by the conveyance roller 80. Thereby, impurities such as dust adhering to the surface of the film can be removed, so that an effect of reducing the possibility of impurities being mixed when forming the coating layer can be obtained. In addition, although the installation location and the number of installed units of the dust remover 90 are not particularly limited, the dust remover 90 is provided on the upstream side of the coating apparatus 10 as in the present embodiment in order to further enhance the above effect. And it is preferable to provide it at a position as close as possible to the coating apparatus 10.

  The dust-removed base film 2 is conveyed downstream of the equipment, and a liquid is applied to the surface by the coating device 10. In the present embodiment, a liquid for forming a layer having a lower refractive index than that of the optical functional layer 26 is applied to the surface of the base film 2 to provide a coating layer that becomes a low refractive index layer. The micro gravure roller 11 of the coating apparatus 10 rotates in the direction opposite to the conveying direction of the base film 2, and an appropriate amount of coating liquid is supplied to the gravure pattern formed on the surface thereof. When such a micro gravure roller 11 is brought into contact with the surface of the base film 2, the coating liquid can be transferred, so that a coating layer can be easily formed on the surface of the base film 2.

  The number of gravure patterns imprinted on the micro gravure roller 11 is preferably 50 to 800 lines / inch, and more preferably 100 to 300 lines / inch. Moreover, it is preferable that the depth of a gravure pattern is 1-600 micrometers, More preferably, it is 5-200 micrometers. Furthermore, the rotational speed of the micro gravure roller 11 is preferably 3 to 800 rpm, more preferably 5 to 200 rpm. In addition, it is preferable that the conveyance speed of the base film 2 shall be 0.5-100 m / min, More preferably, it is 1-50 m / min. As described above, a coating layer having a uniform thickness and little coating unevenness can be formed on the surface of the base film.

The amount of the coating solution is not particularly limited, and may be appropriately selected while preventing the occurrence of repelling on the surface of the base film 2 and considering the desired thickness of the coating layer. . However, if the amount of the coating solution is large, there is a problem that repellency may be formed on the surface of the base film 2 or the drying time may be prolonged. This problem also occurs when the coating layer is too thick. Therefore, in order to avoid this problem, the amount of the coating solution is preferably 1 to 40 ml, particularly preferably ² to 25 ml, per 1 m ² of the base film. In order to form a layer having desired characteristics while preventing the drying time from being prolonged, the thickness of the coating layer is preferably 0.01 to 20 μm, more preferably 0.05 to 10 μm. .

  The base film 2 fed into the drying device 30 is transported in the transport chamber 32 while being supported by the pass rollers 31 with the surface opposite to the coating layer side as a support surface. In the drying device 30, the internal temperature is adjusted by sending drying air whose temperature is adjusted from an air supply pipe (not shown). Thereby, initial drying that promotes drying of the coating layer to some extent can be performed. In addition, it is preferable that the internal temperature of the drying apparatus 30 is 20 to 120 degreeC, More preferably, it is 25 to 100 degreeC. Thereby, drying of an application layer can be advanced without generating heat shrink. However, if the internal temperature is less than 20 ° C., the solvent contained in the coating layer cannot be sufficiently evaporated, and the coating layer containing a large amount of the solvent is heated by the next heating device 40. As a result, in the heating device 40, since the solvent in the coating layer is rapidly evaporated, a large amount of drying unevenness and thickness unevenness are caused, and the appearance failure is remarkably deteriorated. On the other hand, when the internal temperature of the drying device 30 is higher than 120 ° C., the solvent in the coating layer rapidly evaporates inside the drying device 30, so that the coating layer thermally shrinks or the additive is added together with the evaporation of the solvent. There is a possibility that a layer having desired characteristics cannot be formed by evaporation.

  Each pass roller 31 preferably has a function of adjusting the surface temperature. Thereby, the coating layer can be dried more efficiently. At this time, the surface temperature of each pass roller 31 is preferably adjusted to be substantially equal to the temperature inside the drying device 30 in order to suppress drying unevenness of the coating layer.

  The wind speed in the transfer chamber 32 is preferably 0.1 m / second or more and 1.5 m / second or less. More preferably, it is 0.1 m / second or more and 1.0 m / second or less, and particularly preferably 0.2 m / second or more and 1.0 m / second or less. Thereby, the initial drying of the coating layer can be performed efficiently and satisfactorily by the drying device 30 while preventing the appearance failure. However, when the wind speed is 0.1 m / sec or less, the drying efficiency is significantly lowered, and the initial drying of the coating layer cannot be sufficiently performed. For this reason, since the heating device 40 dries the coating layer containing a large amount of the solvent, the solvent rapidly evaporates, resulting in a large amount of uneven drying and uneven thickness in the coating layer. Here, it is not preferable to lengthen the transfer chamber 32 in order to sufficiently dry, since it may cause an increase in equipment cost and a decrease in drying efficiency. On the other hand, if the wind speed is higher than 1.5 m / sec, there is a possibility that uneven thickness may occur in the coating layer, which is a problem.

  After the initial drying of the coating layer is completed, the base film 2 is sent out from the drying device 30 and then sent into the heating device 40. The heating device 40 adjusts the internal temperatures of the front chamber 42a, the middle chamber 42b, and the rear chamber 42c by adjusting the temperature of the dry air supplied from the air supply ducts 43a, 43b, and 43c.

  Here, the temperature of the drying air supplied into the heating device 40 is the temperature of the drying air supplied to the front chamber 42a, that is, the first temperature, the temperature of the drying air supplied to the middle chamber 42b, that is, the second temperature, and the temperature of the drying chamber 42c. The temperature of the supplied drying air, that is, the third temperature, has the following relationship. In the first curing step, which is a curing step in the front chamber 42a, the first temperature is cured at a temperature higher than the second temperature. In the second curing step, which is a curing step in the middle chamber 42b, the second temperature is cured at a temperature lower than the first temperature. Then, in the third curing step, which is a curing step in the rear chamber 42c, the third temperature is again set at a temperature higher than the second temperature.

  It is known that a white powdery substance is generated when the curing temperature is high at the initial stage of curing. However, in the first curing step, which is the initial stage of the initial stage, since the coating layer still contains a large amount of solvent, a white powdery substance is almost always deposited even when drying at high temperature. Absent. Moreover, there exists an effect that hardening time can be shortened by making hardening temperature into high temperature.

  Next, curing is performed in the middle chamber 42b at a second temperature lower than the first temperature. The coating layer on the base film 2 that has passed through the front chamber 42a has a small amount of solvent. Therefore, a white powdery substance is deposited by drying at a high temperature. Therefore, in the second curing step, precipitation of a white powder substance can be prevented by lowering the temperature.

  Finally, curing is performed in the rear chamber 42c at a temperature higher than the second temperature. By raising the third temperature, the coating layer can be sufficiently cured, so that a layer with very high hardness can be obtained.

  The curing temperature is appropriately selected depending on the material of the coating film to be dried, the coating amount, the thickness of the coating film, and the like. Specifically, the first temperature is 100 ° C. or higher and 120 ° C. or lower, preferably 105 ° C. or higher and 110 ° C. or lower. Moreover, 2nd temperature is 85 degreeC or more and 100 degrees C or less, Preferably they are 90 degreeC or more and 95 degrees C or less. Further, the third temperature is 100 ° C. or higher and 120 ° C. or lower, preferably 105 ° C. or higher and 110 ° C. or lower. The temperature of the drying air is adjusted so that the second temperature is lower than the first temperature, and the third temperature is adjusted so as to be higher than the second temperature. The temperature difference between the first temperature and the second temperature is preferably 5 ° C. or more and 15 ° C. or less. The temperature difference between the second temperature and the third temperature is preferably 5 ° C. or more and 15 ° C. or less.

  As described above, in the present invention, when the low refractive index layer is provided, the coating layer after the initial drying is dried at at least three different temperatures, so that the coating can be performed while suppressing elution of additives and the like. After the layer is thermally cured, the curing reaction of the coating layer can be more fully accelerated. Moreover, since the curing temperature in the initial stage of curing can be raised, the curing rate can be improved. For this reason, a white powdery substance due to elution of additives and the like is not generated on the surface, and a very hard layer can be obtained. As a result, there is no appearance failure and excellent scratch resistance. An application layer, that is, a low refractive index layer can be formed.

  However, when the first temperature is less than 100 ° C., the second temperature is less than 85 ° C., and the third temperature is less than 100 ° C., all are problematic because the temperature is too low to promote thermal curing of the coating layer. Here, if the transport speed of the base film 2 is slowed or the transport path is lengthened in order to promote the curing reaction, the productivity decreases due to the prolonged transport time, and the residence time in the heating device 40 In addition to the possibility that the base film 2 may be thermally damaged due to the prolonged time, the cost of equipment is increased due to the increase in equipment size. On the other hand, when the first temperature exceeds 120 ° C., when the second temperature exceeds 100 ° C., or when the third temperature exceeds 120 ° C., the additive contained in the coating layer dissolves on the surface of the coating layer. This is a problem because wrinkles and wrinkles due to appearance failure and thermal contraction of the coating layer may occur.

  Moreover, each hardening process performs a 1st hardening process in the constant rate drying period of a coating film, performs a 2nd hardening process in the decreasing rate drying period of a coating film, a 1st hardening process and a 2nd hardening process. Are preferably divided at the position of the drying change point from the constant rate drying period to the decreasing rate drying period.

  Here, the drying change point will be described. FIG. 3 shows the temperature change of the film surface temperature with respect to the drying time. In FIG. 3, the horizontal axis represents the drying time and the vertical axis represents the film surface temperature, and shows the temperature change of the film surface when the coating film is dried at a constant air speed and air temperature. As shown in FIG. 3, when drying is started, the film surface temperature, which has been the wet bulb temperature, increases from a certain time. The period before the increase is referred to as the constant rate drying period, and the point after the start of the increase is referred to as the decreasing rate drying period. Further, the changing point between the constant rate drying period and the decreasing rate drying period is referred to as a drying change point. In the constant rate drying period in which the film surface temperature is the wet bulb temperature, the movement of volatile components in the film is sufficiently fast to move within the film, and there is a sufficient amount of liquid that volatilizes from the surface. In the rate-decreasing drying period, even if the volatile matter in the film is insufficient on the surface and the same wind is applied, the drying rate is slow. When the solid content is measured at this drying change point, it is between 60 and 80%.

Next, a method for measuring the solid content will be described. Solid content here Solid content (%) = solid content / (volatile content + solid content) × 100
It is. The solid content and (volatile content + solid content) can be obtained from the following formulas (1) and (2) by weight measurement.
Solid content = [A: Weight of dried film] − [B: Weight of support before coating] (1)
Volatile content + solid content = [C: weight of film sampled in a certain drying zone] − [B: weight of support before coating] (2)
Therefore, when a sample is taken in a certain zone, A: a weight that is completely dried above the boiling point of volatile matter,
B: Weight measured by removing A,
C: Weight measured immediately after sampling,
The solid content can be obtained by measuring each.

  The base film 2 after the initial curing is performed by the heating device 40 is irradiated with ultraviolet rays from the ultraviolet lamp 50 toward the surface of the formed low refractive index layer. In this way, when the low refractive index layer is irradiated with ionizing radiation such as ultraviolet rays, the curing of the layer can be further promoted, so that a layer with extremely high hardness can be obtained. In addition, the ionizing radiation in this invention is rays, such as an electron beam, an X-ray, a gamma ray, a fast neutron beam, a fast charged particle beam other than an ultraviolet-ray, and means the radiation which brings an ionization effect | action to the irradiated substance. Finally, the antireflection film 3 is wound around the winder 60. However, the antireflection film 3 is not necessarily in a state (bulk) wound up by the winder 60, and the final form thereof is not particularly limited, for example, a sheet shape.

  The antireflection film 3 formed by the above method has a low refractive index layer 24 that is thermally cured after initial drying and further irradiated with ultraviolet rays, so that there is almost no appearance failure and scratch resistance. It has characteristics such as excellent properties.

  Next, the antireflection film according to the present invention will be described. The support 21 is transparent and is a member serving as a base for forming each layer, but is preferably a plastic film made of a polymer. Examples of the polymer include cellulose ester, polyamide, polycarbonate, polyester, polystyrene, polyolefin, norbornene resin, and amorphous polyolefin. Among these, it is preferable to use cellulose ester triacetyl cellulose, polyesters polyethylene terephthalate and polyethylene naphthalate, and triacetyl cellulose is particularly preferable.

  The optical functional layer 26 has a function as an optical functional layer, and is composed of at least one layer made of a binder, a polymerization initiator, a dispersant, or the like that is a polymer. Therefore, the optical functional layer 26 may have a multilayer structure of two or more layers. In the present embodiment, an optical functional layer 26 having a multilayer structure composed of the first layer 22 and the second layer 23 is formed. Examples of the layer constituting the optical functional layer include a light diffusion layer, a middle refractive index layer, a high refractive index layer, an optical compensation layer, and an antiglare layer. The layers constituting the optical functional layer 26 may be of the same type or may be layers having different compositions. The desired optical functional layer 26 may be formed by appropriately selecting from the above. However, in order to obtain an excellent antireflection effect, it is preferable that an antiglare property-imparting layer is included as a layer.

  Further, the binder used in the optical function layer 26 is preferably a polymer having a saturated hydrocarbon chain or a polyether chain as a main chain. By using a polymer as a binder by appropriately selecting the structure of the monomer constituting such a polymer, the presence or absence of an aromatic ring, the presence or absence of an atom such as a halogen atom, a sulfur atom, a phosphorus atom or a nitrogen atom. The refractive index of the layer to be formed can be suitably adjusted.

  A plurality of translucent fine particles 25 are added to the second layer 23. In the present invention, fine particles that do not absorb in the visible light region are referred to as translucent fine particles. When a plurality of such translucent fine particles 25 are added to the layer, the refractive index of the layer can be easily adjusted by the action of the fine particles, and the translucent fine particles transmit light. The antiglare property can be suitably adjusted. The translucent particles are specifically described in [0044] of JP-A No. 2003-302506, and can be applied to the present invention. In addition, it is preferable that the light-transmitting fine particles are appropriately selected in consideration of the refractive index difference according to the refractive index of the layer to be formed.

  Various characteristics of the layer to be formed can be controlled by properly using the light-transmitting fine particles in consideration of the difference in refractive index and particle size. For example, the use of light-transmitting fine particles having a large particle diameter can easily adjust the antiglare property of the layer, and the use of light-transmitting fine particles having a smaller particle diameter can easily adjust the refractive index of the layer. be able to. Therefore, it is preferable to use two or more types of translucent fine particles having different types and sizes. Thereby, for example, even if there is unevenness on the film surface which is a problem in order to reduce the uniformity of brightness, the above problem can be improved by using the light-transmitting fine particles while selecting the particle size. Can do.

  As described above, it is preferable that the refractive index of the optical functional layer 26 is 1.58 or more and 2.0 or less by appropriately selecting and using the light-transmitting fine particles. The refractive index of the low refractive index layer 24 is preferably 1.31 or more and 1.45 or less. The optical functional layer 26 as described above has excellent antiglare properties. The low refractive index layer 24 as described above has characteristics such as high hardness and resistance to scratches on the surface. Therefore, the antireflection film 3 composed of such a layer is an optical film excellent in antiglare property, scratch resistance, antifouling property and the like. The translucent fine particles are preferably contained in at least one of the optical function layer 26 or the low refractive index layer 24. Further, when the optical functional layer 26 or the like is composed of a plurality of layers as in the present embodiment, it may be contained in at least one of the layers.

The translucent fine particles are preferably at least one metal oxide of titanium, zirconium, aluminum, indium, zinc, tin, and antimony. The average particle size is preferably 0.2 μm or less, more preferably 0.1 μm or less, and particularly preferably 0.06 μm or less. Examples of the metal oxides, _{e.g., TiO 2, ZrO 2, Al} 2 O 3, In 2 O 3, ZnO, SnO 2, Sb 2 O 3, ITO, SiO ₂ or the like can be mentioned. Among these, TiO ₂ and ZrO ₂ are preferable in terms of increasing the refractive index. In addition, it is preferable to treat the surface of each fine particle with a silane coupling agent or a titanium coupling agent because dispersibility and compatibility with the binder can be improved. The addition amount of the fine particles is preferably 10 to 90%, more preferably 20 to 80%, and particularly preferably 30 to 75% with respect to the total mass of the layer to be added.

Of the translucent fine particles, as fine particles used for the purpose of imparting antiglare properties, mat particles having a particle size larger than the filler particles and an average particle size of about 1 to 10 μm can be preferably used. Examples of the mat particles include inorganic compound particles such as silica particles and TiO ₂ particles, and organic compound particles such as acrylic particles, cross-linked acrylic particles, polystyrene particles, cross-linked styrene particles, melamine particles, and benzoguanamine particles. Among them, it is preferable to use crosslinked styrene particles, crosslinked acrylic particles, and silica particles because high antiglare properties can be expressed. The shape of the mat particle is not particularly limited, regardless of whether it is a true sphere or an indefinite shape. Two or more kinds of mat particles having different particle sizes and shapes can be used in combination. In order to form the antiglare layer, the content of the matte particles is preferably a 10~2000mg to layer 1 m ² around to form. More preferably, it is 100-1400 mg.

  The mat particles are preferably uniformly dispersed in the layer. Moreover, it is preferable that the particle diameter of each particle is substantially the same. For example, when particles larger than the average particle diameter by 20% or more are used as coarse particles, the ratio of coarse particles contained in all particles is preferably 1% or less, more preferably 0.1% or less. . Therefore, it is preferable to use mat particles having substantially the same particle diameter and subjected to as many strong classifications as possible for the purpose of uniform dispersion in the layer. Note that the fine particles described above have a particle size sufficiently smaller than the wavelength of light, and thus light scattering does not occur.

  The optical functional layer preferably contains at least one of a fluorine-based compound and a silicone-based compound having a surface active action. By appropriately selecting and using such a compound, an optical functional layer having excellent antifouling properties and slipperiness can be formed. In addition, it is preferable that said compound shall be 0.01-20 mass% with respect to the total solid content of the layer forming material used for layer formation. More preferably, it is 0.05-10 mass%, Most preferably, it is 0.1-5 mass%.

  As the fluorine compound, a compound having a fluoroalkyl group is preferable. The fluoroalkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms. In this case, it may be a straight chain, branched structure, or alicyclic structure, or may have an ether bond. A plurality of fluoroalkyl groups may be contained in the same molecule.

  The fluorine-based compound preferably has a substituent that affects compatibility and adhesion at the interface between the optical functional layer and the low refractive index layer. These substituents may be the same or different, but preferably have a plurality. Examples of the substituent include acryloyl group, methacryloyl group, vinyl group, aryl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, polyoxyalkylene group, carboxyl group, amino group and the like. The fluorine compound may be a copolymer of a compound containing no fluorine atom and a compound containing a fluorine atom, or may be a copolymer oligomer, and the molecular weight thereof is not particularly limited. The fluorine atom content in the fluorine compound is not particularly limited, but is preferably 20% by mass with respect to the total amount of fluorine atoms. More preferably, it is 30-70 mass%, Most preferably, it is 40-70 mass%.

  Examples of the silicone compound include those having a substituent at the terminal and side chain of the compound chain containing a plurality of dimethylsilyloxy units as repeating units, or at either the terminal or the side chain. In addition, the compound containing the above units repeatedly may contain a structural unit other than dimethylsilyloxy. The substituents may be the same or different, but preferably have a plurality. Preferable examples of the substituent include acryloyl group, methacryloyl group, vinyl group, aryl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, fluoroalkyl group, polyoxyalkylene group, carboxyl group, amino group and the like. . Although there is no restriction | limiting in particular in molecular weight, In view of handleability etc., it is preferable that it is 100,000 or less. More preferably, it is 50000 or less, Most preferably, it is 3000-30000. The silicone atomic weight of the silicone compound is not particularly limited, but is preferably 18% by mass or more, more preferably 25 to 37.8% by mass, and particularly preferably 30 to 37% by mass with respect to the total amount of the compound. It is.

  The low refractive index layer 24 formed on the base film 2 will be described. The low refractive index layer is preferably a cured film formed by applying, drying and curing a curable composition containing at least one monomer having two or more crosslinkable reactive groups. The monomer having two or more crosslinkable reactive groups is preferably an aldehyde compound containing two or more aldehyde groups.

  Specific compounds include, for example, glyoxal, malonaldehyde, succinaldehyde, glutaraldehyde, adipaldehyde, pimeroaldehyde, suberoaldehyde, azelaaldehyde, sebacoaldehyde, aspartaldehyde, 1,2,4-butanetri Carbaldehyde, 3-formylhexane dial, cyclohexane dicarbaldehyde, cyclohexane diacetaldehyde, phthalaldehyde, isophthalaldehyde, terephthalaldehyde, benzenetrialdehyde, 1,4,5,8-naphthalenetetraacetaldehyde, both end aldehyded povalaldehyde, Examples include dialdehyde starch. The aldehyde compound used in the present invention is not limited to these.

  Among these, a highly reactive bifunctional (two aldehyde groups) aliphatic aldehyde compound is preferable.

  FIG. 2B shows an example of another form of the antireflection film that can be formed by the film manufacturing apparatus 1. As shown in FIG. 2B, the antireflection film 110 is composed of a support 21, an optical function layer 115, and a low refractive index layer 116. In addition, since the support body 21 is the same as what was demonstrated and shown in Fig.2 (a), it attaches | subjects the same code | symbol. The optical functional layer 115 has a multilayer structure in which a first layer 112, a second layer 113, and a third layer 114 are stacked in order from the support 21. Here, a layer having a function as a hard coat layer is formed as the first layer 112, a medium refractive index layer is formed as the second layer 113, and the third layer is selected by appropriately selecting the kind of fine particles and binder. When a high refractive index layer is formed as 114, an antireflection film 110 having excellent antireflection properties can be obtained.

  As for the coating method, in this embodiment, a method that is generally known as a microgravure coating method is used, but the present invention is not limited to this method. Examples of the coating method that can be suitably used in the present invention include a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a micro gravure coating method, and an extrusion coating method (for example, As described in US Pat. No. 2,681,294). Among these, in order to form a coating layer having a uniform thickness and less coating unevenness, it is preferable to use a wire bar coating method, an extrusion coating method, or a micro gravure coating method, and in particular, to use a micro gravure coating method. preferable.

  In the present embodiment, the heating device 40 has three sections. However, the number of the sections is not particularly limited as long as the first temperature, the second temperature, and the third temperature can be controlled. Is possible. In addition, the heating device 40 may be in a form in which a plurality of drying apparatuses capable of individually adjusting the internal temperature are combined, or separate drying apparatuses are arranged in parallel, instead of being partitioned. Form may be sufficient.

  Further, when the ionizing radiation is irradiated to the heat-cured low refractive index layer, in the present embodiment, the mode of irradiating with ultraviolet rays is shown.For example, instead of the ultraviolet rays, the electron beam which is ionizing radiation is irradiated, These can also be used in combination. Thus, when using a plurality of ionizing radiations together, prepare a desired irradiation device such as an ultraviolet irradiation device or an electron beam irradiation device, and use them in parallel to provide a low refractive index layer. What is necessary is just to irradiate an ultraviolet-ray and an electron beam continuously. In addition, the installation location, order, etc. of each irradiation apparatus are not specifically limited, It is possible to select suitably.

  As the ultraviolet irradiation device, for example, a known ultraviolet irradiation device such as a high-pressure mercury lamp, a xenon lamp, a metal halide lamp, or a fusion lamp can be suitably used. Also, the ionizing radiation irradiation apparatus is not particularly limited, and various ionizing radiation irradiation apparatuses can be used. However, when irradiating with ionizing radiation, for the purpose of sufficiently promoting curing while reducing damage to the base film, the irradiation amount is preferably 30 mJ or more and 800 mJ or less. More preferably, it is set to 50 mJ or more and 300 mJ or less, and when ionizing radiation is used, the accelerated electron pressure is preferably set to 80 kV or more and 300 kV or less.

  In addition, it is related with the formation method of each layer etc., such as the support body which concerns on this invention, curable resin used for forming an optical function layer and a low-refractive-index layer, microparticles | fine-particles, and additives, such as a polymerization initiator and a dispersing agent. Details are described in detail in JP-A-2005-257786, [0061], and this description can also be applied to the present invention.

  The antireflection film obtained by the present invention can be suitably used as a protective film for a polarizing plate. The polarizing plate is mainly composed of two protective films sandwiching the polarizing film from both sides, and is preferably used for at least one of the protective films. At this time, since the antireflection film also serves as a protective film, the manufacturing cost of the polarizing plate can be reduced, and by using the antireflection film as the outermost layer, reflection of light from the outside is prevented, and scratch resistance A polarizing plate having excellent antifouling properties and the like can be obtained. In addition, it is preferable that one of the two protective films is an antireflection film and the other is an optical compensation film having an optically anisotropic layer. Such an optical compensation film can be used to form an optical functional layer having an optically anisotropic layer. The optical compensation film is also called a retardation film, and can improve the viewing angle characteristics of the liquid crystal display screen.

  As described above, when the antireflection film obtained by the present invention is used as a protective film for a polarizing film, it can be used for a TN, STN, VA, IPS, OCB or other mode transmissive, reflective, or transflective liquid crystal display device. It can be used suitably.

  As the polarizing film, a known polarizing film or a polarizing film cut out from a long polarizing film whose absorption axis is neither parallel nor perpendicular to the longitudinal direction may be used, and the polarizing film is not particularly limited. The latter polarizing film is formed by stretching by applying tension to the width direction while holding both ends of the continuously supplied polymer film by the holding means. The film is stretched at a rate of 1.1 to 20 times at least in the width direction, and the difference in the traveling speed with respect to the longitudinal direction of the film in the holding means at both ends of the film is within 3%. When the direction of travel of the film is bent while holding both ends of the film so that the angle between the direction of travel and the direction of substantial stretching of the film is inclined by 20 to 70 °, a polarizing film having a desired stretch is produced. be able to. In addition, when said angle is set to 45 degrees, it is preferable from a viewpoint of productivity.

  The antireflection film obtained by the present invention can be preferably used for image display devices such as LCD, PDP, ELD, and CRT. Further, when an antireflection film having a transparent support as obtained by the present invention is used with the transparent support side adhered to the image display surface of the image display device, an image display device having excellent display quality can be provided. .

  The polarizing film, polymer film, image display device and the like relating to the antireflection film of the present invention are described in JP-A-2005-257786, [0067] and thereafter, and this description also applies to the present invention. Can do.

  Hereinafter, the practical effects of the present invention will be described by way of examples, but the present invention is not limited to these examples.

<Example 1>
[Preparation of base film]
Diameter having a gravure pattern of 135 lines / inch and a depth of 60 μm on the surface of a triacetylcellulose film (TD80U, manufactured by Fuji Film Co., Ltd.) as a support, using an optical functional layer forming liquid A described later as a coating liquid. A 50 mm micro gravure roller and a doctor blade were used for coating at a conveying speed of 20 m / min to provide a coating layer. Thereafter, the coating layer was dried at 100 ° C. for 40 seconds. Subsequently, the surface of the coating layer is irradiated with ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 250 mJ / cm ² using a 160 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) under a nitrogen purge. Thus, the coating layer was cured to form an optical functional layer A having an action as an optical functional layer. The thickness of the optical functional layer A after curing was about 10 μm. In addition, the film in which this optical function layer A was formed was wound up by the winding roll, and the roll-shaped base film (diffusion film A) which is a light-diffusion film was obtained.

[Preparation of antireflection film]
An antireflection film was produced by the film production apparatus 1 shown in FIG. First, on the surface of the base film produced as described above, a coating layer is provided by applying a low refractive index layer coating solution A described later as a coating solution by the coating device 10, and then the drying device 30 is used for 120 seconds at 120 ° C. Meanwhile, the coating layer was dried. The coating apparatus 10 uses a form including a micro gravure roller 11 having a diameter of 200 μm / inch and a gravure pattern having a depth of 30 μm and a diameter of 50 mm and a doctor blade. It was 30 rpm and the conveyance speed was 20 m / min. Next, the temperature of the drying air in the front chamber 42a of the heating device 40 is set to 105 ° C., the temperature of the drying air in the middle chamber 42b is set to 95 ° C., and the temperature of the drying air in the rear chamber 42c is set to 105 ° C. The coating layer was heated and cured at a heating time of ˜42c for 2 minutes. Thereafter, using an ultraviolet-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) under a nitrogen purge as an ultraviolet lamp 50, drying promotes ultraviolet rays with an illuminance of 400 mW / cm ² and an irradiation amount of 900 mJ / cm ^2. The coated layer was irradiated to obtain an antireflection film. In this antireflection film, the thickness of the low refractive index layer was 100 nm.

[Optical function layer forming liquid A]
First liquid (zirconia-containing UV curable hard coat liquid; manufactured by JSR Corporation, Desolite Z7404, solid content concentration: about 61% by mass, ZrO ₂ content in solid content: about 70% by mass, polymerizable monomer, polymerization initiator Contained) 100 parts by mass / second liquid (mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate; manufactured by Nippon Kayaku Co., Ltd., DPHA) 30 parts by mass / methyl isobutyl ketone 21 parts by mass / methyl ethyl ketone 6 parts by mass Silane coupling agent A (acryloyloxypropyltrimethoxysilane; manufactured by Shin-Etsu Chemical Co., Ltd., KBM-5103) 98 parts by mass The above composition was mixed and stirred to prepare a mixed solution A1. In addition, after apply | coating this liquid mixture A1 to a triacetyl cellulose film (TD80UF, Fuji Photo Film Co., Ltd. product) and providing an application layer, the layer obtained by irradiating this application layer with an ultraviolet-ray and making it harden | cure The refractive index of was 1.61.

  Next, 35 parts by mass of a fine particle dispersion A containing classified strengthened crosslinked PMMA particles (manufactured by Soken Chemical Co., Ltd., MXS-300, refractive index 1.49) having an average particle size of 3.0 μm is added to the mixed solution A1. Thereafter, 90 parts by mass of a fine particle dispersion B containing silica particles having an average particle diameter of 1.5 μm (manufactured by Nippon Shokubai Co., Ltd., Seahosta KE-P150, refractive index 1.46) was added to obtain a mixed liquid A2. And this liquid mixture A2 was used as the optical function layer forming liquid A which can form a light-diffusible hard-coat layer by filtering with a polypropylene filter with a pore diameter of 30 μm. The fine particle dispersion A is a dispersion obtained by dispersing a methyl isobutyl ketone dispersion containing 30% by mass of the above PMMA particles in a polytron dispersing machine at 10,000 rpm for 20 minutes. The fine particle dispersion B is a dispersion obtained by dispersing a methyl ethyl ketone dispersion containing 30% by mass of the above silica particles with a polytron disperser at 10,000 rpm for 30 minutes.

[Low refractive index layer coating solution A]
The following composition is put into a mixing tank, stirred, and then filtered through a polypropylene filter having a pore size of 1 μm to prepare a low refractive index layer coating solution A which is a coating solution for forming a low refractive index layer. did.
First polymer solution (thermally crosslinkable fluorine-containing polymer composition; manufactured by JSR Corporation, Opstar JN7228A) 100 parts by mass Silica dispersion A (Nissan Chemical Co., Ltd., MEK-ST, average particle size 15 nm) 4 .3 parts by mass-Silica Dispersion B (manufactured by Nissan Chemical Co., Ltd., MEK-ST different particle size, average particle size 45 nm) 5.1 parts by mass-sol solution E 2.2 parts by mass-methyl ethyl ketone 15.0 Mass part · Cyclohexanone 3.6 parts by mass However, the sol solution E was prepared by the method described later.

[Sol solution E]
In a reactor equipped with a stirrer and a reflux condenser, 120 parts by mass of methyl ethyl ketone, 100 parts by mass of silane coupling agent A, 3 parts by mass of diisopropoxyaluminum ethyl acetoacetate (manufactured by Hope Pharmaceutical Co., Ltd.), After addition, this was mixed to make a mixture. Next, 30 parts by mass of ion-exchanged water was added to the mixture, and the mixture was reacted at 60 ° C. for 4 hours, and then cooled to about room temperature to obtain a sol solution E. The sol solution E had a mass average molecular weight of 1800, and among the components higher than the oligomer component, the component having a molecular weight of 1000 to 20000 was 100% by mass. It was confirmed by gas chromatography analysis that no silane coupling agent A as a raw material remained in the sol solution E.

<Example 2>
An antireflection film was produced in the same manner as in Example 1 except that the film surface temperature of the coating layer in the front chamber 42a and the rear chamber 42c was 110 ° C.

<Example 3>
In Example 1, instead of the optical functional layer forming liquid A, an optical functional layer forming liquid B shown below is used, and a roll-shaped base film (antiglare hard coating layer film B) which is an antiglare hard coat layer film is used. ) The base film was manufactured in the same manner as in Example 1 except that the antireflective film was manufactured by applying the low refractive index layer coating solution B to the surface of the base film.

[Optical function layer forming liquid B]
-Third liquid (mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate; Nippon Kayaku Co., Ltd., PETA) 50 parts by mass-Toluene 38.5 parts by mass-Polymerization initiator A (Ciba Specialty Chemicals Co., Ltd.) Manufactured by Irgacure 184) 2 parts by mass The above composition was mixed and stirred to prepare a mixed solution B1. A layer obtained by applying this mixed solution B1 to a triacetylcellulose film (TD80UF, manufactured by Fuji Photo Film Co., Ltd.) to provide a coating layer, and then irradiating the coating layer with ultraviolet rays and curing it. The refractive index of was 1.51.

  Next, 1.7 mass of the fine particle dispersion C containing polystyrene particles (manufactured by Soken Chemical Co., Ltd., SX-350, refractive index 1.60) having an average particle size of 3.5 μm in the mixed solution B1. After adding 1 part by mass, 13.3 parts by mass of the fine particle dispersion D containing acrylic-styrene particles having an average particle size of 3.5 μm (manufactured by Soken Chemical Co., Ltd., refractive index 1.55) was added, and the mixture B2 was added. Prepared. Then, 0.75 parts by mass of the fluorine-based surface modifier (FP-13, mass average molecular weight 14000; refer to [0080] of JP-A-2005-283849) and 10 silane coupling agent A are added to the mixed solution B2. An optical functional layer forming liquid B for forming an anti-glare hard coat layer was added with parts by mass. In addition, the fine particle dispersion C is a dispersion obtained by dispersing a mixed liquid in which the above polystyrene particles are contained in toluene at a ratio of 30% by mass with a polytron dispersing machine at 10,000 rpm for 20 minutes. The fine particle dispersion D is a mixed liquid in which the above-mentioned acrylic-styrene particles are contained in toluene at a ratio of 30% by mass.

[Low refractive index layer coating solution B]
The following composition is put into a mixing tank, stirred, and then filtered through a polypropylene filter having a pore size of 1 μm to prepare a low refractive index layer coating solution B which is a coating solution for forming a low refractive index layer. did.
・ Second polymer solution (thermally crosslinkable fluorine-containing polymer composition; manufactured by JSR Corporation, OPSTAR JTA-113) 100 parts by mass ・ Silica dispersion A 4.3 parts by mass ・ Silica dispersion B 5.1 parts by mass Sol liquid E 2.2 parts by mass, methyl ethyl ketone 15.0 parts by mass, cyclohexanone 3.6 parts by mass

<Example 4>
An antireflection film was produced in the same manner as in Example 3 except that the film surface temperature of the coating layer in the front chamber 42a and the rear chamber 42c was 110 ° C.

<Example 5>
Reflection is performed in the same manner as in Example 3 except that the low refractive index layer coating liquid H is applied instead of the low refractive index layer coating liquid G, and the temperature of the coating layers in the front chamber 42a and the rear chamber 42c is 100 ° C. A prevention film was produced.

[Low refractive index layer coating solution C]
The following composition was put into a mixing tank, stirred, and then filtered through a polypropylene filter having a pore size of 1 μm to prepare a low refractive index layer coating solution C.
-Second polymer solution 100 parts by mass-Silica dispersion A 4.3 parts by mass-Silica dispersion B 5.1 parts by mass-Sol liquid E 2.2 parts by mass-Methanol 10.0 parts by mass-Methyl ethyl ketone 5.0 parts by mass Parts / cyclohexanone 3.6 parts by mass

<Example 6>
An antireflection film was produced in the same manner as in Example 5 except that the temperature of the coating layer in the front chamber 42a and the rear chamber 42c was 105 ° C.

<Example 7>
An antireflection film was produced in the same manner as in Example 5 except that the temperature of the coating layers in the front chamber 42a and the rear chamber 42c was 110 ° C.

<Example 8>
An antireflection film was produced in the same manner as in Example 6 except that the temperature of the coating layer in the middle chamber 42b was 100 ° C.

<Example 9>
An antireflection film was produced in the same manner as in Example 7 except that the temperature of the coating layer in the middle chamber 42b was 85 ° C.

<Example 10>
In Example 1, instead of the optical functional layer forming liquid A, an optical functional layer forming liquid C shown below was used to obtain a roll-shaped base film (high refractive index film C) as a high refractive index film. The base film was manufactured in the same manner as in Example 1 except that the antireflective film was manufactured by applying the low refractive index layer coating solution B to the surface of the base film.

[Optical functionality forming liquid C]
An optical functional layer having a high refractive index can be formed by filtering the mixture obtained by putting the following materials into a mixing tank and stirring the mixture with a filtration device having a polypropylene filter having a pore diameter of 0.4 μm. An optical functional layer forming solution C was prepared as a coating solution that can be used.
-Titanium dioxide dispersion 88.9 parts by mass-Second liquid 58.9 parts by mass-Polymerization initiator B (manufactured by Ciba Specialty Chemicals Co., Ltd., Irgacure 907) 3.1 parts by mass-Photosensitizer (Nipponization) Yaku Co., Ltd., Kayacure DETX) 1.1 parts by mass / methyl ethyl ketone 482.4 parts by mass / cyclohexanone 1869.8 parts by mass The titanium dioxide dispersion prepared by the following method was used.

[Titanium dioxide dispersion]
The following materials were prepared by dispersing with a dynomill until the mass average diameter became 70 nm.
Fine particle dispersion F (manufactured by Ishihara Sangyo Co., Ltd., MPT-129C (TiO ₂ : Co ₃ O ₄ : Al ₂ O ₃ : ZrO ₂ in mass ratio, 90.5: 3.0: 4.0: 0) .5) 257.1 parts by mass / Dispersant A 38.6 parts by mass / cyclohexanone 704.3 parts by mass

<Example 11>
An antireflection film was produced in the same manner as in Example 8, except that the temperature of the coating layer in the front chamber 42a and the rear chamber 42c was 110 ° C.

<Comparative Examples 1-9>
In the method for producing an antireflection film of Examples 1 to 9, a heating device consisting of two chambers was used instead of the heating device 40, and the heating time in each room was set to 5 minutes. An antireflection film was formed.

<Evaluation results>
The following items were evaluated using the antireflection films prepared in each Example and Comparative Example.

[1. Average reflectance]
Using a spectrophotometer (U4100, manufactured by Hitachi, Ltd.), the spectral reflectance of the sample at an incident angle of 5 ° was measured in a wavelength region of 380 to 780 nm. And the average reflectance of 450-650 nm was made into the average reflectance of an optical film.

[2. Pencil hardness scratch resistance]
The antireflection film was conditioned at a temperature of 25 ° C. and a humidity of 60% RH for 2 hours, and then pencil hardness was evaluated by the method described in JIS K 5400.

[3. Steel wool scratch resistance]
The surface of the film was rubbed 10 times under a load of 500 g using steel wool # 0000, and then the level of scratching was confirmed. The determination was in accordance with the following criteria.

○: No scratches are observed Δ: Fine scratches are visible ×: Scratches are remarkable

[4. Bencott scratch resistance]
Using a Gakushin type friction fastness tester (Tester Sangyo Co., Ltd., AB-301), a rubbing test was performed on the sample under the conditions described below. And after applying oily black ink to the surface opposite to the low refractive index layer side of the sample that has been rubbed, the surface on the low refractive index layer side is visually observed, and scratches on the rubbed portion seen by reflected light are observed. Was evaluated according to the following criteria as the Bencott scratch resistance of the optical film in three stages.

  ○: Even when viewed very carefully, no scratches are visible, and there is no problem on the product.

  Δ: Some weak scratches can be seen, but acceptable in product.

  X: There are scratches that can be confirmed at first glance, which also causes problems on the product.

[Rubbing test conditions]
-Evaluation environmental conditions: 25 ° C, 60% RH
・ Scraping material: A tester that comes into contact with the sample was wrapped with Bencot (M-3, manufactured by Asahi Kasei Kogyo Co., Ltd.) around the tip (1 cm × 1 cm) of the tester, and then fixed with a band.
・ Movement distance (one way): 13cm
・ Rubbing speed: 13 cm / sec ・ Load: 200 g / cm ²
-Tip contact area: 1 cm x 1 cm
・ Rubbing frequency: 250 round trips

[5. White powder breakdown]
When the low refractive index layer of the sample was used as the surface, oil-based black ink was applied to the surface located on the back surface of this surface, and then the surface of the low refractive index layer was irradiated with a light source. And the grade of the white powder failure which can be confirmed on the surface at this time was evaluated in three stages according to the following criteria. As the light source, a three-wavelength fluorescent lamp and an artificial sunlight lamp were used.

  ○: No white powder failure has occurred, and appearance quality does not cause a problem on the product.

  Δ: White powder failure is thin, but the appearance quality is acceptable on the product.

  X: A white powder failure occurs on the entire surface, which causes a problem in appearance quality.

  The evaluation results obtained in each example and comparative example are shown in FIGS.

  The antireflection films of Comparative Examples 1 to 9 are excellent in Bencott scratch resistance and white powder failure, but the antireflection film having a pencil hardness scratch resistance of 3H and a low film surface temperature of 105 ° C. during curing is steel wool. As for the scratch resistance, some weak scratches were confirmed. Further, the antireflection films of Examples 1 to 9 also had a pencil hardness scratch resistance of 4H, which was higher than that of the comparative example, and good results were obtained for all the samples with respect to the steel wool scratch resistance.

  In addition, regarding the curing time, the examples were cured in 2 minutes for each step and a total of 6 minutes, whereas the comparative example was cured for 5 minutes in each step for a total of 10 minutes. Therefore, it was confirmed that the curing time can be shortened.

  From the above results, according to the present invention, an antireflection film having excellent quality in which the appearance failure is suppressed to such an extent that white powder failure is hardly confirmed while being excellent in scratch resistance is manufactured with excellent productivity. Can do.

It is the schematic of an example of the film manufacturing apparatus which concerns on this invention. It is sectional drawing (a) of an example of the optical film which concerns on this invention, and sectional drawing (b) of another example. It is a figure which shows the temperature change of the film surface temperature with respect to the drying time on fixed temperature conditions. It is a figure which shows the result of an Example. It is a figure which shows the result of a comparative example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Film manufacturing apparatus, 2 ... Base film, 3, 110 ... Antireflection film, 10 ... Coating apparatus, 11 ... Micro gravure roller, 21 ... Support body, 22, 112 ... 1st layer, 23, 113 ... 2nd layer , 114 ... third layer, 24, 116 ... low refractive index layer, 25 ... translucent fine particles, 26, 115 ... optical functional layer, 30 ... drying device, 31 ... pass roller, 32 ... transport chamber, 33 ... exhaust chamber, 34 ... Air conditioning plate, 40 ... Heating device, 41 ... Partition plate, 42a ... Front chamber, 42b ... Middle chamber, 42c ... Rear chamber, 43 ... Duct, 50 ... Ultraviolet lamp, 60 ... Winding machine, 70 ... Sending machine, 80 ... conveying roller, 90 ... dust remover

Claims (11)

A reflection having a support, at least one optical functional layer disposed on the support, and a low refractive index layer disposed on the optical functional layer and having a refractive index lower than that of the optical functional layer In the manufacturing method of a prevention film,
An application step of forming a coating layer by applying a liquid for forming the low refractive index layer on the surface of the optical functional layer;
A drying step for promoting drying of the coating layer;
A curing step in which drying is accelerated and the coating layer is thermally cured to form a low refractive index layer;
The curing step includes a first curing step of curing the coating layer at a dry air of a first temperature, the coating layer after the first curing step in dry air of lower than said first temperature second temperature A second curing step for curing the coating layer; and a third curing step for curing the coating layer with a drying air having a third temperature higher than the second temperature on the coating layer after the second curing step. , have a,
The first temperature is 100 ° C. or higher and 120 ° C. or lower, the second temperature is 85 ° C. or higher and 100 ° C. or lower, and the third temperature is 100 ° C. or higher and 120 ° C. or lower . Production method.   The method for producing an antireflection film according to claim 1, wherein the support is a transparent support having an Re value of 0 to 200 nm.   The first curing step is a constant rate drying period of the coating film, the second curing step is a decreasing rate drying period of the coating film, the first curing step and the second curing step, 3. The method for producing an antireflection film according to claim 1, wherein: is partitioned at a position of a drying change point from the constant rate drying period to the decreasing rate drying period.   The method for producing an antireflection film according to claim 3, wherein the drying change point is in a range of 60 to 80% of the solid content in the coating film. Wherein the optical functional layer, one of claims 1, characterized in that the optically functional layer forming composition containing at least one selected from among fluorine compounds and silicone compounds with surface activity 4 A method for producing an antireflection film as described above. The low refractive index layer, method of manufacturing the anti-reflection film according to any one of claims 1 5, characterized in that it contains a curing compound including at least one kind of monomer having two or more crosslinkable reactive groups. The method for producing an antireflection film according to claim 6, wherein the monomer having two or more crosslinkable reactive groups is an aldehyde compound containing two or more aldehyde groups. Antireflection film produced by the method according to any one of claims 1 7. The antireflection film according to claim 8 , wherein the optical functional layer is an antiglare property-imparting layer. The antireflective film according to claim 8 or 9, wherein the refractive index of the optical functional layer is 1.58 or more and 2.00 or less. The refractive index of the low refractive index layer, an antireflection film according to any one of claims 8, wherein 10 to be at 1.31 to 1.45.

Images