JP2015203768A - Manufacturing method of retardation film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a retardation film, capable of suppressing cissing in an alignment film, a retardation layer, etc. formed on a film base material, when manufacturing a retardation film utilizing the film base material with foreign substances such as a protein material adhered thereon.SOLUTION: In a manufacturing method of a retardation film 1, through conveying and sequentially treating a long film base material 11, an alignment film 12 and a retardation layer 13 are laminated on the film base material 11 in this order to obtain a retardation film 1. Cleansing is performed through making the film base material 11 contact with solvent including isopropyl alcohol by a gravure roll before applying an alignment film composition for forming the alignment layer 12.

Description

  The present invention relates to a method for producing a retardation film, and more specifically, by sequentially processing a long film substrate while conveying the film, an alignment film and a retardation layer are formed in this order on the film substrate. The present invention relates to a method for producing a retardation film obtained by laminating.

  In recent years, flat panel displays capable of three-dimensional display have been provided. In the three-dimensional image display, it is necessary to selectively provide a right-eye video and a left-eye video to the viewer's right eye and left eye, respectively, using, for example, a passive method.

  In the passive method, pixels that are continuous in the vertical direction of the image display panel are sequentially assigned to the right eye and the left eye, and driven by the image data for the right eye and the left eye, respectively. Display images simultaneously. In addition, a retardation film is disposed on the panel surface of the image display panel, and light emitted by linearly polarized light from the right-eye and left-eye pixels is converted into circularly polarized light having different directions for the right-eye and left-eye. Accordingly, in the passive method, glasses equipped with corresponding polarizing filters are attached, and a right eye image and a left eye image are selectively provided to the viewer's right eye and left eye, respectively.

  In the retardation film, an alignment film and a retardation layer (liquid crystal layer) are sequentially provided on a substrate made of a transparent film material. In the retardation film, the retardation layer is formed of a liquid crystal material, and the alignment of the liquid crystal material is patterned by the alignment regulating force of the alignment film. The alignment film exhibiting the alignment regulating force is manufactured by various manufacturing methods as described in Patent Documents 1 and 2, for example. By this patterning, in the retardation film, the right eye region and the left eye region are alternately formed with a constant width in correspondence with the pixel assignment in the liquid crystal display panel, and the right eye region and the left eye region are sequentially formed. A phase difference corresponding to each of the light emitted from the pixels is given.

  Thus, in the image display device, the image display panel is driven by the sequentially input image data, the pixels of the odd lines and the even lines are driven by the image data for the right eye and the left eye, respectively, and for the right eye and the left eye. Display images simultaneously. Also, the output light from the image display panel is converted to linearly polarized light by the polarizing filter placed on the image display panel, and the right and left eyes are handled by the retardation film placed on the polarizing filter. To give the phase difference.

  By the way, in an image display device such as a liquid crystal display device, various optical films for the purpose of hard coating, antireflection, electromagnetic wave shielding and the like are provided on the panel surface of the image display panel. In these optical films, various functional layers corresponding to the intended function are provided on the surface of the substrate made of a transparent film, and an adhesive layer (adhesive layer) is provided for the purpose of bonding to the upper and lower layers. It is done. Here, the adhesive layer is produced, for example, by applying an adhesive to the entire surface of the substrate, and is provided for attaching the optical film to a desired object. Thereby, the optical film mentioned above is affixed and hold | maintained on a panel surface by an adhesive layer in the manufacture process of an image display apparatus.

  In such an optical film, foreign substances such as human sebum (for example, about 20 to 30 μm) may adhere to the base material constituted by the film for some reason. In such a case, when the alignment film and retardation layer (liquid crystal layer) necessary for the production of the optical film are applied, and further an adhesive layer such as a primer layer or UV adhesive is applied, the difference in surface free energy Therefore, repelling occurs in each layer. Such a repellency has a diameter that can be seen (for example, about 300 μm), and is a defect as a product.

JP 2005-49865 A JP 2010-152296 A

  The present invention has been proposed in view of such circumstances, and in producing a retardation film using a film substrate to which foreign substances such as proteins are attached, an alignment film formed on the film substrate, It aims at providing the manufacturing method of the phase difference film which can suppress generation | occurrence | production of the repellency in a phase difference layer.

  This inventor repeated earnest examination for solving the subject mentioned above. As a result, prior to applying the alignment film composition for forming the alignment film on the film substrate, the gravure roll coated with a predetermined solvent is brought into contact with the film substrate and subjected to a cleaning treatment. Thus, the present inventors have found that it is possible to effectively remove foreign substances adhering to the film base material and to suppress the occurrence of repellency in the layer formed on the base material, thereby completing the present invention. That is, the present invention provides the following.

  (1) The present invention is a retardation film obtained by laminating an alignment film and a retardation layer in this order on the film substrate by sequentially treating the film substrate while conveying a long film substrate. A manufacturing method, wherein before the alignment film composition for forming the alignment film is applied, the film substrate is cleaned by bringing a solvent containing isopropyl alcohol into contact with the gravure roll. A method for producing a retardation film.

  (2) Moreover, this invention is a manufacturing method of the phase difference film characterized by the said film base material consisting of an acrylic resin in the invention which concerns on (1).

  (3) Moreover, this invention is a manufacturing method of the phase difference film characterized by the said solvent which is the invention which concerns on (1) or (2) being a mixed solvent of isopropyl alcohol and toluene.

  (4) Moreover, this invention is a manufacturing method of the phase difference film characterized by the said mixed solvent containing isopropyl alcohol in the ratio which is 50 mass% or more in the invention which concerns on (3).

  (5) Moreover, this invention is the invention which concerns on either of (1) thru | or (4), and conveys the said film base material with the conveyance speed of 10 m / min-50 m / min with respect to the said gravure roll. It is the manufacturing method of the retardation film characterized.

  (6) In the invention according to any one of (1) to (4), the contact length between the gravure roll and the film substrate is 2 cm to 10 cm. It is a manufacturing method.

  (7) Moreover, this invention is a manufacturing method of the retardation film characterized by the draw ratio being 50% to 150% in the invention according to any one of (1) to (4).

  According to the present invention, foreign substances such as proteins adhering to the surface of the film substrate can be effectively removed, so that an alignment film, a retardation layer, an adhesive layer, and the like formed on the film substrate are used. Even when the film is formed, the occurrence of cissing in each layer can be effectively suppressed, and the appearance defect of the retardation film can be prevented.

It is sectional drawing of a phase difference film. It is sectional drawing which shows the optical film which affixed the polarizer on retardation film. It is a figure which shows typically a mode that repelling has arisen in alignment film, a phase difference layer, a primer layer, and an adhesive bond layer by foreign materials, such as a protein adhering on a film base material. It is a figure which shows an example of the manufacturing apparatus of retardation film. It is the schematic which showed the structure of the base-material washing | cleaning part typically. It is a figure where it uses for description of the 1st exposure part and 2nd exposure part in a manufacturing apparatus. It is the figure which showed the pattern of the phase difference layer typically.

Hereinafter, specific embodiments of the present invention (hereinafter referred to as “present embodiments”) will be described in detail in the following order with reference to the drawings. In addition, this invention is not limited to the following embodiment, A various change is possible in the range which does not change the summary of this invention.
1. 1. Outline of production method of retardation film 2. Configuration of retardation film 3. Method for producing retardation film 3-1. Surface cleaning of film substrate (Pretreatment method)
3-2. Retardation film production equipment

<< 1. Outline of retardation film manufacturing method >>
FIG. 1 is a cross-sectional view of a retardation film 1 according to the present embodiment. As shown in FIG. 1, the retardation film 1 has an alignment film 12 formed on a long film base material (hereinafter simply referred to as “base material”) 11 made of, for example, an acrylic resin, and the alignment film 12. A retardation layer (liquid crystal layer) 13 is formed by applying a polymerizable liquid crystal composition for forming a retardation layer thereon.

  In such a retardation film 1, the retardation layer 13 formed on the base material 11 is bonded or transferred to a polarizer via an adhesive layer such as a UV adhesive, and is applied to the retardation film 1. An optical film on which a polarizer is bonded is formed. Specifically, FIG. 2 is a cross-sectional view showing an example of the optical film 2. As shown in FIG. 2, the optical film 2 is obtained by bonding a polarizer 21 to a retardation film 1 via an adhesive layer 20 made of a UV adhesive or the like.

  Here, in the retardation film 1, foreign matters such as human sebum (for example, about 20 μm to 30 μm (width direction)) may adhere to the film base material that supports the alignment film, the retardation layer, and the like for some reason. . In such a case, a coating liquid for applying an alignment film composition and a liquid crystal composition on the substrate, and further forming a primer layer on the formed retardation layer, and a coating liquid for forming an adhesive layer When the coating is applied, due to the difference in surface free energy, so-called “repellency” occurs in which the coating liquid cannot be uniformly applied and the lower layer is exposed. FIG. 3 is a diagram schematically showing how the alignment film, the retardation layer, the primer layer, and the adhesive layer are repelled by foreign substances such as proteins adhering to the film substrate made of acrylic resin or the like. is there.

  As shown in FIG. 3, the foreign matter adhering to the film substrate has a visible diameter (eg, about 300 μm), and the height is about 3 μm to 4 μm. Thus, when repelling occurs due to the foreign matter adhering to the base material, the phase difference of the part where the repelling occurs is reduced, causing a defect or the like to cause an appearance defect, resulting in a defect as a product. Moreover, the occurrence of such repellency also reduces the yield of the retardation film. In ordinary films, foreign substances adhering to the substrate are removed by a slightly adhesive roll, etc., but in that case, the adhesive component may be transferred from the slightly adhesive roll to the substrate, resulting in the orientation of the retardation film. The problem of deteriorating the sex occurs.

  Therefore, in the present embodiment, a retardation obtained by laminating an alignment film and a retardation layer in this order on the film substrate by sequentially treating the long film substrate while conveying it. In the method for producing a film, before applying an alignment film composition for forming an alignment film, a cleaning treatment is performed by bringing a predetermined solvent into contact with the film substrate by a gravure method. Specifically, a solvent containing isopropyl alcohol is used as the solvent.

  In this way, by bringing a solvent containing isopropyl alcohol into contact with the film substrate by the gravure method, the solvent causes foreign substances such as proteins attached on the film substrate to float, and the surface of the gravure roll It is possible to scrape (scrap off) foreign matter that has been lifted by engraving (surface irregularities).

  In the method for producing a retardation film according to the present embodiment, before the alignment film composition for forming the alignment film is applied, the film base material is subjected to a cleaning treatment in this manner, thereby forming a foreign material. Is removed and the wettability of the film substrate surface is improved. After that, even when an alignment film composition, a liquid crystal composition, or a composition for forming a primer layer or an adhesive layer is applied. The occurrence of repelling in each layer formed on the film substrate can be prevented.

  Moreover, according to this method for producing a retardation film, the surface of the film base is modified by subjecting the film base to a cleaning treatment as described above. Adhesiveness with the alignment film formed thereon can be improved.

≪2. Composition of retardation film >>
Prior to description of a more specific method for producing a retardation film according to the present embodiment, first, the configuration of the retardation film shown as an example in FIGS. 1 and 2 will be briefly described.

(1) Substrate (film substrate)
The base material 11 is a transparent film material, has a function of supporting the alignment film 12, and is formed in a long shape. The substrate 11 preferably has a small phase difference, and an in-plane retardation (in-plane retardation value (Re value)) is preferably in the range of 0 nm to 10 nm, and is in the range of 0 nm to 5 nm. It is more preferable that it is in the range of 0 nm to 3 nm. If the Re value exceeds 10 nm, for example, the display quality of a flat panel display using a pattern alignment film may deteriorate, which is not preferable.

  As a film material which comprises the base material 11, it is preferable that it is a flexible material which has the flexibility which can be wound up in roll shape. Examples of such flexible materials include acrylic polymers (acrylic resins), polyethylene terephthalate, polybutylene terephthalate, polyesters such as polyethylene naphthalate and polyarylate, polyolefins such as polyethylene, polypropylene and polymethylpentene, and triacetyl cellulose. Can be mentioned.

  Among these film base materials, in the case of a base material made of an acrylic resin, foreign substances such as proteins are likely to adhere. In the method for producing a retardation film according to the present embodiment, even such an acrylic base material can be suitably used, and a retardation film can be produced while suppressing the occurrence of cissing.

  Although it does not specifically limit as thickness of the base material 11, For example, it is preferable to set it as the range of 20 micrometers-200 micrometers. If the thickness of the substrate 11 is less than 20 μm, it may not be possible to provide the minimum necessary self-supporting property as a retardation film, which is not preferable. On the other hand, when the thickness exceeds 200 μm, when the retardation film is long, the processing waste increases when the long retardation film is cut into a single-phase retardation film. Or wear of the cutting blade may be accelerated.

  The base material 11 is not restricted to the structure which consists of a single layer, You may have the structure by which the several layer was laminated | stacked. When it has the structure by which the several layer was laminated | stacked, the layer of the same composition may be laminated | stacked, and the several layer which has a different composition may be laminated | stacked.

(2) Alignment film The alignment film 12 consists of the hardened | cured material obtained by apply | coating (coating) the composition for alignment films (alignment film composition) on the base material 11, and making it harden | cure. Although this alignment film 12 is not specifically limited, For example, it can form by the photo-alignment system which aligns by light irradiation using the photo-alignment material which exhibits photo-alignment property by polarized light irradiation.

  The alignment film 12 may be a pattern alignment film formed in a pattern or a solid film formed in a solid form on the substrate 11. In the case of a pattern alignment film, the alignment pattern may be formed by, for example, a rubbing process in which the uneven shape is rolled with a roll having an uneven shape, and the photo-alignment property is obtained by irradiation with polarized light as described above. You may form by the photo-alignment system made to align by light irradiation using the photo-alignment material to exhibit. When forming a pattern alignment film by rubbing, the alignment film (pattern alignment film) 12 may be any material that contains a widely used energy ray curable resin (such as an ultraviolet curable resin). Also good.

  For example, when the alignment film (photo-alignment film) 12 is formed by a photo-alignment method, the alignment film 12 contains an alignment film composition. This alignment film composition contains a photo-alignment material that exhibits photo-alignment properties when irradiated with polarized light, and a solvent that dissolves the photo-alignment material.

(Photo-alignment material)
The photo-alignment material refers to a material that can exhibit an alignment regulating force by irradiation with polarized ultraviolet rays. The alignment regulating force means that an alignment film containing a photo-alignment material is formed, and a liquid crystal compound (polymerizable liquid crystal composition for forming a retardation layer) is formed on the alignment film, The function to arrange in the direction.

  The photo-alignment material is not particularly limited as long as it exerts alignment regulating force by irradiating polarized light. Such photo-alignment materials include a photoisomerization material that reversibly changes the alignment regulation force by changing only the molecular shape by cis-trans change, and a photoreactive material that changes the molecule itself by irradiating polarized light. Can be broadly classified. In the present embodiment, either a photoisomerization material or a photoreactive material can be suitably used, but it becomes possible to express an orientation regulating force irreversibly, and stability over time of the orientation regulating force. It is more preferable to use a photoreactive material because it is excellent in the above. Among photoreactive materials, it is more preferable to use a photodimerization type material from the viewpoint of stability and reactivity (sensitivity).

  Examples of the photodimerization-type material include polymers having cinnamate, coumarin, benzylidenephthalimidine, benzylideneacetophenone, diphenylacetylene, stilbazole, uracil, quinolinone, maleinimide, or cinnamylideneacetic acid derivatives. Among them, a polymer having one or both of cinnamate and coumarin is preferably used from the viewpoint of good alignment regulating power. In addition, only one type of photo-alignment material may be used, or two or more types may be mixed and used.

(solvent)
The solvent used in the alignment film composition is not particularly limited as long as it can dissolve the above-described photo-alignment material at a desired concentration. For example, hydrocarbon solvents such as benzene and hexane, methyl ethyl ketone, methyl isobutyl Ketone solvents such as ketone and cyclohexanone, ether solvents such as tetrahydrofuran, 1,2-dimethoxyethane and propylene glycol monoethyl ether, alkyl halide solvents such as chloroform and dichloromethane, methyl acetate, ethyl acetate, butyl acetate and propylene Ester solvents such as glycol monomethyl ether acetate, amide solvents such as N, N-dimethylformamide, sulfoxide solvents such as dimethyl sulfoxide, anone solvents such as cyclohexane, methanol, ethanol, isopropyl alcohol It can be exemplified an alcohol solvent such Lumpur. In addition, one type of solvent may be used alone, or two or more types of mixed solvents may be used.

  Further, the amount of the solvent is not particularly limited, but is preferably about 600 to 3900 parts by mass with respect to 100 parts by mass of the photo-alignment material. If the amount of the solvent is less than 600 parts by mass, the photo-alignment material may not be dissolved uniformly. On the other hand, when the amount of the solvent exceeds 3900 parts by mass, a part of the solvent remains, and when the alignment film composition is applied onto the substrate, the remaining solvent penetrates into the substrate, As a result, both the photo-alignment property and the adhesion to the substrate may be reduced.

  The thickness of the alignment film 12 is not particularly limited as long as it is within a range in which a desired alignment regulating force can be expressed with respect to a liquid crystal compound (polymerizable liquid crystal composition for forming a retardation layer) described later, but is 100 nm to 1000 nm. It is preferable to be within the range. When the thickness of the alignment film 12 is less than 100 nm, there is a possibility that a desired alignment regulating force cannot be expressed for the liquid crystal compound. On the other hand, if the thickness exceeds 1000 nm, the adhesion may be reduced.

(3) Retardation layer (liquid crystal layer)
The retardation layer (liquid crystal layer) 13 contains a polymerizable liquid crystal composition. This polymerizable liquid crystal composition contains a liquid crystal compound (rod-like compound) exhibiting liquid crystallinity and having a polymerizable functional group in the molecule.

  The liquid crystal compound has refractive index anisotropy and has a function of imparting a desired retardation by regularly arranging the liquid crystal compound. Examples of the liquid crystal compound include materials exhibiting a liquid crystal phase such as a nematic phase and a smectic phase, but the nematic phase is easier in order to arrange regularly than liquid crystal compounds exhibiting other liquid crystal phases. It is preferable to use a material exhibiting the above liquid crystallinity. In addition, when the alignment film 12 described above is made of a vertical alignment film and the liquid crystal compound is homeotropically aligned, there is no particular limitation as long as it is a homeotropic liquid crystal material capable of forming homeotropic alignment.

  The liquid crystal compound is a polymerizable liquid crystal compound having a polymerizable functional group in the molecule as described above. By having a polymerizable functional group, it is possible to polymerize and fix the liquid crystal compound, so that the alignment stability is excellent and the phase change is less likely to occur over time. The polymerizable liquid crystal compound more preferably has a polymerizable functional group capable of three-dimensional crosslinking in the molecule. By having a polymerizable functional group capable of three-dimensional crosslinking, the sequence stability can be further enhanced. Note that “three-dimensional crosslinking” means that liquid crystal molecules are polymerized three-dimensionally to form a network structure. Examples of the polymerizable functional group include those that polymerize by the action of ionizing radiation such as ultraviolet rays and electron beams, or heat, and more specifically, radical polymerizable functional groups, cationic polymerizable functional groups, and the like. Is mentioned.

  The amount of the polymerizable liquid crystal compound is not particularly limited as long as the viscosity of the retardation layer forming coating liquid (liquid crystal composition) can be adjusted to a desired value according to the coating method applied onto the alignment film 12. For example, the amount in the liquid crystal composition can be in the range of about 5 to 40 parts by mass. In addition, a polymeric liquid crystal compound can be used individually by 1 type or in mixture of 2 or more types.

  The liquid crystal compound described above is usually dissolved in a solvent (dilution solvent). The solvent is not particularly limited as long as it can uniformly disperse liquid crystal compounds and the like. For example, hydrocarbon solvents such as benzene and hexane, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, tetrahydrofuran, 1, Ether solvents such as 2-dimethoxyethane and propylene glycol monoethyl ether, alkyl halide solvents such as chloroform and dichloromethane, ester solvents such as methyl acetate, ethyl acetate, butyl acetate and propylene glycol monomethyl ether acetate, N, N -Examples include amide solvents such as dimethylformamide, sulfoxide solvents such as dimethyl sulfoxide, anone solvents such as cyclohexane, and alcohol solvents such as methanol, ethanol, isopropyl alcohol. Kill, but is not limited to these. Moreover, one type of solvent may be single and 2 or more types of mixed solvents may be sufficient as it.

  The amount of the solvent is not particularly limited, and can be, for example, about 66 parts by mass to 900 parts by mass with respect to 100 parts by mass of the liquid crystal compound. If the amount of the solvent is less than 66 parts by mass, the liquid crystal compound may not be dissolved uniformly. On the other hand, when it exceeds 900 mass parts, a part of solvent may remain | survive and reliability may fall and it may not be able to apply uniformly.

  In addition, the liquid crystal composition may contain other compounds as necessary, as long as the alignment order of the liquid crystal compounds described above is not impaired. Examples thereof include a polymerization inhibitor, a plasticizer, a surfactant, and a silane coupling agent.

  The thickness of the retardation layer 13 formed by coating the liquid crystal composition as described above on the alignment film 12 is not particularly limited, but in order to obtain appropriate alignment performance, the thickness is about 500 nm to 2000 nm. Preferably there is.

≪3. About production method of retardation film >>
<3-1. Surface cleaning of film substrate (pretreatment method)>
As described above, foreign substances such as proteins such as human sebum may adhere to the film substrate constituting the retardation film for some reason. In such a case, a coating liquid for applying an alignment film composition and a liquid crystal composition on the substrate, and further forming a primer layer on the formed retardation layer, and a coating liquid for forming an adhesive layer When coating is performed, cissing occurs in each layer due to the difference in surface free energy (see the schematic diagram in FIG. 3). The occurrence of repelling due to such foreign matters adhering to the base material reduces the phase difference at that portion, causes defects and the like, causes a poor appearance, and becomes a defect as a product.

  Therefore, in the method for producing a retardation film according to the present embodiment, prior to the application of the alignment film composition for forming the alignment film 12 on the film substrate 11, the film substrate 11 is subjected to coating. The cleaning process is performed by bringing a predetermined solvent into contact with the gravure roll. Specifically, a solvent containing isopropyl alcohol is brought into contact with the film substrate using a gravure method. In the present embodiment, as described above, the solvent containing isopropyl alcohol is brought into contact with the film substrate 11 by the gravure method, whereby the foreign matter attached to the surface of the film substrate is lifted by the solvent, and The foreign matter in the lifted state can be scraped off (scratched) by engraving (surface irregularities) on the surface of the gravure roll.

  According to the method for producing a retardation film according to the present embodiment, the film substrate 11 is subjected to the above-described washing treatment as a pretreatment, thereby removing foreign substances and improving the wettability of the surface of the film substrate 11. Even when an alignment film composition, a liquid crystal composition, or a composition for forming a primer layer or an adhesive layer is applied on the film base material 11, the film base material 11 is coated on the base material 11. The occurrence of cissing in each formed layer can be prevented.

  Further, as a secondary effect of such a cleaning process for the film base material 11, the adhesion between the film base material 11 and the alignment film 12 formed on the film base material 11 can be enhanced.

  As described above, a solvent containing isopropyl alcohol is used as a solvent to be applied using the gravure method. The solvent may include isopropyl alcohol alone, but may be a mixed solvent with other organic solvents. The other solvent in the case of the mixed solvent is not particularly limited as long as it can effectively lift the foreign material on the surface of the film substrate as a mixed solvent with isopropyl alcohol. For example, methanol, ethanol, isobutyl alcohol Lower alcohols such as dibutyl ether, isopropyl ether and tetrahydrofuran, ketones such as acetone, diethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, methyl propyl ketone and cyclohexanone, ethyl acetate, n-propyl acetate, n-acetate Examples thereof include esters such as butyl and aromatic hydrocarbons such as benzene, toluene and xylene. Among these, it is particularly preferable to use a mixed solvent of isopropyl alcohol and toluene.

  Moreover, when using a mixed solvent, it is preferable to mix so that content of isopropyl alcohol may be 50 mass% or more. For example, when a mixed solvent of isopropyl alcohol and toluene is used, it is preferable to contain isopropyl alcohol in a proportion of 50% by mass or more and less than 100% by mass.

<3-2. Retardation Film Manufacturing Equipment>
Here, the manufacturing apparatus used for the manufacturing method of the retardation film which concerns on this Embodiment is demonstrated. FIG. 4 is a diagram illustrating an example of the retardation film manufacturing apparatus 3. The manufacturing apparatus 3 manufactures a retardation film by sequentially processing a long film base material 11 made of an acrylic resin or the like while conveying it.

  Specifically, the manufacturing apparatus 3 includes a base material providing unit 31 that provides the film base material 11, and an alignment film forming unit 32 that forms the alignment film 12 by applying the alignment film composition to the film base material 11. The first exposure unit 33 that exposes the first polarized light through the first mask having a predetermined shape along the flow direction of the substrate 11 to form the first alignment region, and the second exposure portion 33 having the predetermined shape along the flow direction. A second exposure part 34 that exposes a second polarized light different from the first polarized light through a mask to form a second alignment region, and a composition for forming a retardation layer (liquid crystal composition) on the alignment film 12 A retardation layer forming composition coating portion 35 for coating 13 ′, a retardation layer forming portion 36 for forming the retardation layer 13 from the retardation layer forming composition 13 ′, and the retardation layer 13 are formed. And a take-up part 37 for taking up the film after being wound.

  And in this Embodiment, the base-material washing | cleaning part 30 for wash | cleaning the surface of the film base material 11 is provided in the front | former stage of the base-material provision part 31, It is characterized by the above-mentioned. In this base-material washing | cleaning part 30, before applying the coating liquid which consists of alignment film composition with respect to the film base material 11 as above-mentioned, the removal of the foreign material adhering to the surface of the film base material 11 is removed. Do.

[Substrate cleaning unit 30]
The substrate cleaning unit 30 cleans and removes foreign substances such as proteins attached to the surface of the film substrate before applying the alignment film composition for forming the alignment film 12 on the film substrate 11.

  In FIG. 5, the schematic which showed the structure of the base-material washing | cleaning part 30 typically is shown. As shown in FIG. 5, the substrate cleaning unit 30 includes a transport roll mechanism 61 that transports a long film substrate 11 having a predetermined width while applying a predetermined tension, and a gravure roll 62 coated with a predetermined solvent. Is provided.

  The conveyance roll mechanism 61 conveys and sends out the long film base material 11 wound up in a roll shape by a plurality of rollers. In the transport roll mechanism 61, as indicated by an arrow X in FIG. 5, it can be moved up and down in the height direction, and by changing the transport position of the film substrate 11 in the height direction in this way. The contact length (L in FIG. 5) between the gravure roll 62 and the film substrate 11 can be adjusted. The contact length L between the gravure roll 62 and the film substrate 11 will be described later.

  The gravure roll 62 applies the solvent containing isopropyl alcohol to the film base 11 transported with a predetermined tension by the transport roll mechanism 61, and engraves the surface of the film base 11 by surface engraving (surface irregularities). Scrape off foreign material on the surface. As shown in FIG. 5, a part of the gravure roll 62 is accommodated in a predetermined container 62 </ b> A, and a solvent containing isopropyl alcohol stored in the container 62 </ b> A is applied to the surface of the gravure roll 62. It has become so. As this gravure roll 62, what is generally used by the coating by the gravure (coat) method can be used. The gravure roll 62 is provided with a doctor 62B at a predetermined position of the roll (position immediately before contact with the film substrate 11 after solvent application with respect to the rotation direction) to adjust the amount of solvent applied to the roll. It is possible to do.

  In the base-material washing | cleaning part 30 which consists of such a structure, as above-mentioned, the elongate film base material 11 is conveyed to the gravure roll 62 by the conveyance roll mechanism 61, and the gravure roll is conveyed with respect to the conveyed film base material 11 At 62, a solvent containing isopropyl alcohol is brought into contact. As a result, the foreign matter on the surface of the film substrate 11 is lifted by the solvent applied to the surface of the gravure roll 62, and the foreign matter is scraped off (scratched off) by the surface irregularities formed on the surface of the gravure roll 62. It becomes like this.

  Here, when the film base material 11 is brought into contact with the gravure roll 62, it is preferable to appropriately adjust the degree of contact. If the contact between the film substrate 11 and the gravure roll 62 is too weak (too small), there is a possibility that foreign matter on the surface of the film substrate 11 is sufficiently lifted and cannot be scraped off, while the contact is too strong. When the film is rubbed to the inside of the film substrate 11 and an alignment film or retardation layer is formed on the substrate 11, the alignment of the liquid crystal compound in the retardation layer is adversely affected. Properties may be degraded. Therefore, in the substrate cleaning unit 30, the transport roll mechanism 61 and the gravure roll 62 are appropriately controlled in the following points, for example, so that the film substrate 11 and the gravure roll 62 are appropriately brought into contact with each other. It is preferable to make it.

  For example, the line (conveyance) speed of the film substrate 11 conveyed by the conveyance roll mechanism 61 is not particularly limited, but is preferably 10 m / min to 50 m / min, and about 20 m / min to 40 m / min. More preferably. When the line speed is less than 10 m / min, the time until drying is delayed and the solvent penetrates more than expected into the film substrate 11, so that the orientation group becomes insufficient on the substrate surface, and the orientation may deteriorate. There is sex. On the other hand, if the line speed exceeds 50 m / min, the drying speeds up, so that the solvent cannot sufficiently and sufficiently penetrate the film base material 11, and the adhesiveness of the solvent to the base material 11 is lowered. There is a possibility that foreign matter on the surface of the film substrate 11 cannot be removed by washing.

  The draw ratio is not particularly limited, but is preferably 50% to 150%, more preferably 100 to 120%. Here, the draw ratio is the ratio of the converted peripheral speed when the rotation speed of the gravure roll 62 with respect to the transport speed of the film substrate 11 is converted into the peripheral speed, and the value (ratio) when the transport speed is 100. It is. If the draw ratio is less than 50%, the contact length between the film substrate 11 and the gravure roll 62 per unit length may be shortened, and the amount of scraping of foreign matter adhering to the substrate may be reduced. There is. On the other hand, when the draw ratio exceeds 150%, the gravure roll 62 comes into contact with the film base material 11 in a state where the solvent supply is insufficient, and thus the base material 11 may be damaged.

  Further, the contact length between the film base 11 and the gravure roll 62 (“L” in FIG. 5) is not generally determined depending on the above-described line speed or the like, but for example, about 2 cm to 10 cm It is preferable to do. When the contact length L is less than 2 cm, the contact between the film substrate 11 and the gravure roll 62 becomes very weak, and there is a possibility that the foreign matter on the surface of the film substrate 11 cannot be sufficiently washed away. On the other hand, when the contact length L exceeds 10 cm, the contact between the film substrate 11 and the gravure roll 62 becomes too strong, and the optical properties of the obtained retardation film 1 are rubbed to the inside of the film substrate 11. May be reduced.

  The line speed, the draw ratio, and the contact length L described above are conditions that are related to the contact between the film base material 11 and the gravure roll 62, and are cleaned by appropriate contact while considering each condition. It is preferable to set so that processing can be realized.

[Substrate providing unit 31]
The base material provision part 31 provides the base material 11 from the long film wound up by the roll. The base material provision part 31 will not be specifically limited if a long film can be conveyed continuously, A general conveyance means can be used. Further, it is preferable that the sheet is conveyed with a predetermined tension applied. Specifically, an unwinder for supplying a roll-shaped long film, a winder for winding the long film, a belt conveyor, a transport roll, and the like can be used. Further, a levitating conveyance table that conveys the film for forming a long alignment film in a floating state by discharging and sucking air may be used.

[Alignment film forming section 32]
The alignment film forming unit 32 forms an alignment film (photo-alignment film) 12 by applying, for example, an alignment film composition for forming a photo-alignment film to the provided base material 11. As described above, the alignment film composition contains, for example, a photo-alignment material that exhibits photo-alignment by irradiation with polarized light, and a solvent that dissolves the photo-alignment material.

  In the alignment film forming part 32, for example, a gravure coating technique is applied to apply the alignment film composition onto the substrate 11, but the present invention is not limited thereto. Specifically, in addition to the gravure coating method, reverse coating method, knife coating method, dip coating method, spray coating method, air knife coating method, roll coating method, printing method, dipping and lifting method, curtain coating method, die coating method, Coating may be performed by a casting method, a bar coating method, an extrusion coating method, an E-type coating method, or the like.

  The thickness of the alignment film composition applied to the substrate 11 is not particularly limited as long as the desired planarity can be achieved, but is preferably in the range of 0.03 μm to 10 μm. More preferably within the range of 0.03 μm to 5 μm, even more preferably within the range of 0.05 μm to 3 μm.

[First exposure unit 33 and second exposure unit 34]
The 1st exposure part 33 moves the base material 11 after photo-alignment film formation to the flow direction continuously or discontinuously, and exposes 1st polarization | polarized-light through the striped 1st mask along a flow direction. A stripe-shaped first alignment region is formed. In addition, the second exposure unit 34 exposes the second polarized light different from the first polarized light through the stripe-shaped second mask along the flow direction, and forms a stripe-shaped second alignment region between the first alignment regions. Form.

  The first exposure unit 33 and the second exposure unit 34 will be described with reference to FIG. First, as shown in FIG. 6A, the first alignment preparation region 12′A corresponding to the right eye region is not shielded, and only the second alignment preparation region 12′B corresponding to the left eye region is shielded. Through the first mask 41, ultraviolet rays (polarized ultraviolet rays) by linearly polarized light are irradiated toward the photoalignment film forming layer 12 ′. As a result, the first alignment preparation region 12'A that is not shielded from light is aligned in a desired direction. Subsequently, as shown in FIG. 6B, the first alignment preparation region 12′B corresponding to the region for the left eye is not shielded, and only the second alignment preparation region 12′A corresponding to the region for the right eye is used. Through the light-shielded second mask 42, ultraviolet rays (polarized ultraviolet rays) by linearly polarized light are irradiated toward the photo-alignment film forming layer 12 ′. Thereby, the second alignment preparation region 12'B that is not shielded from light is aligned in a desired direction. Two types of alignment patterns are formed by these two UV irradiations. In this example, the first alignment preparation region 12'A is irradiated with polarized ultraviolet light, and then the second alignment preparation region 12'B is irradiated with polarized ultraviolet light, but this is not restrictive.

  The material constituting the masks 41 and 42 is not particularly limited as long as a desired opening can be formed, and examples thereof include metals, quartz, and ceramics that are hardly deteriorated by ultraviolet rays. Specifically, a metal substrate such as SUS that has been patterned by etching, laser processing, or electroforming, and further subjected to surface treatment such as nickel plating as necessary can be used.

  The polarization direction of the polarized ultraviolet rays is not particularly limited as long as the polarization direction with respect to the region corresponding to the region for the right eye is different from the polarization direction with respect to the region corresponding to the region for the left eye, but differs by 90 ° between the two. It is preferable.

  The polarized ultraviolet rays may be collected or may not be collected. However, when the pattern irradiation is performed on the long film on the transport roll, that is, the polarized ultraviolet rays are When a difference in the distance from the light source of polarized ultraviolet rays occurs in the irradiated region, the light is preferably condensed with respect to the transport direction. The wavelength of the polarized ultraviolet light is appropriately set according to the photo-alignment material to be used, and can be set to a wavelength used when the orientation regulating force is expressed in a general photo-alignment material. Can use irradiation light having a wavelength of 210 nm to 380 nm, preferably 230 nm to 380 nm, more preferably 250 nm to 380 nm.

  Examples of ultraviolet light sources include low-pressure mercury lamps (sterilization lamps, fluorescent chemical lamps, and black lights), high-pressure discharge lamps (high-pressure mercury lamps, metal halide lamps), short arc discharge lamps (super-high pressure mercury lamps, xenon lamps, mercury xenon). Lamp) and the like. Among these, a metal halide lamp, a xenon lamp, a high-pressure mercury lamp, and the like can be preferably used.

In this embodiment, since the masks 41 and 42 are used in both the first exposure and the second exposure, the irradiation amount of polarized ultraviolet rays in the first exposure and in the second exposure The irradiation amount of polarized ultraviolet rays is preferably the same. By making the irradiation amount the same, the degree of the alignment regulating force of the alignment film 12 for each alignment region can be made the same. The irradiation amount of polarized ultraviolet rays needs to be able to form an alignment region having a desired alignment regulating force. When the wavelength is 310 nm, it is preferably within a range of 5 mJ / cm ^{2 to} 500 mJ / cm ^2. more preferably ^{2 ~300mJ} / cm is in the range of ^2, and still more preferably in the range of ^{5mJ / cm 2 ~100mJ / cm 2} .

  Moreover, when irradiating polarized ultraviolet rays with respect to a thin film, it is preferable to adjust temperature so that the temperature of a thin film may become fixed. Thereby, the alignment region can be formed with high accuracy. The temperature of the thin film is preferably 15 ° C to 90 ° C, and more preferably 15 ° C to 60 ° C. Examples of the temperature control method include a method using a temperature control device such as a general heating / cooling device.

[Phase difference layer forming composition coating part 35]
The phase difference layer forming composition coating part 35 is provided on the alignment layer (photo-alignment film) 12 after exposure, and the phase difference layer forming composition (liquid crystal composition) 13 used for forming the phase difference layer 13. 'Coating. As described above, the retardation layer forming composition (liquid crystal composition) 13 ′ contains a liquid crystal compound that exhibits liquid crystallinity and has a polymerizable functional group in the molecule. The liquid crystal compound has a refractive index anisotropy and has a function of imparting a desired retardation by regularly arranging the alignment material along an alignment pattern that is expressed by irradiating polarized ultraviolet rays to the photo-alignment material. Have.

  In the phase difference layer forming composition coating section 35, the phase difference layer forming composition 13 ′ is applied onto the alignment film 12 from the supply device. A specific coating method is not particularly limited as long as it can stably form a coating film made of the retardation layer forming composition 13 ′ on the alignment film 12.

[Retardation layer forming portion 36]
The phase difference layer forming part 36 forms a liquid crystal phase with a leveling part 51 for uniformizing the layer thickness of the phase difference layer forming composition 13 ′ and a liquid crystal compound contained in the coating film of the phase difference layer forming composition 13 ′. A drying unit 52 for heating to a temperature or higher and a third exposure unit 53 for irradiating the liquid crystal compound with energy rays are provided.

  The leveling unit 51 makes the layer thickness of the retardation layer forming layer uniform. The thickness of the retardation layer forming layer composed of the retardation layer forming composition 13 ′ is in a range in which the in-plane retardation of the retardation layer 13 formed thereafter corresponds to λ / 4 minutes. It is preferable to apply as described above. Thereby, as shown in FIG. 7 to be described later, the linearly polarized light passing through the first phase difference region 13A and the second phase difference region 13B can be made into circularly polarized light that is orthogonal to each other.

  The drying unit 52 heats the liquid crystal compound contained in the coating film of the retardation layer forming composition 13 ′ to a temperature higher than the liquid crystal phase formation temperature, and the first alignment region and the first alignment region included in the alignment film (photo-alignment film) 12. The liquid crystal compounds are aligned along different alignment directions of the two alignment regions.

  FIG. 7 is a diagram schematically showing the pattern of the retardation layer 13 formed using the manufacturing apparatus 3. The retardation film 1 is formed by sequentially forming an alignment film (photo-alignment film) 12 and a retardation layer 13 on a substrate 11 made of a transparent film material. The pattern of the retardation layer 13 is the same as the pattern of the alignment film 12, and the first retardation region 13A is formed on the first alignment region, and the second retardation region 13B is formed on the second alignment region. The

  When the liquid crystal compound is heated above the liquid crystal phase formation temperature by the drying unit 52, not only the liquid crystal compound is arranged in a desired direction, but also the coating film of the retardation layer forming composition 13 'is dried. The drying of the coating film may be appropriately adjusted according to the amount of solvent remaining, but the wind speed of the drying air applied to the coating film is preferably 3 m / second or less, and particularly preferably 2 m / second or less. . The temperature condition depends on the liquid crystal → isotropic phase transition temperature of the liquid crystal used, but is preferably in the range of about 40 ° C. to 150 ° C., and in the range of about 50 ° C. to 120 ° C. Is more preferable, and it is particularly preferably within a range of about 55 ° C to 110 ° C. The drying time is preferably in the range of about 0.2 to 30 minutes, more preferably in the range of about 0.5 to 10 minutes, and about 0.5 to 5 minutes. It is particularly preferable that the value falls within the range. By satisfying these conditions, the solvent can be removed stably.

  The third exposure part 53 polymerizes and cures the polymerizable liquid crystal compound contained in the coating film of the retardation layer forming composition 13 ′. The method for polymerizing the polymerizable liquid crystal compound may be arbitrarily determined according to the type of the polymerizable functional group of the liquid crystal compound. For example, an appropriate amount of a polymerization initiator is added and cured by irradiation with actinic radiation. The method can be used. The actinic radiation is not particularly limited, but it is preferable to use ultraviolet light or visible light, and specifically, it can be the same as the ultraviolet light used when forming the alignment film 12. By undergoing such a curing treatment, they can be polymerized to form a network structure, so that the retardation layer 13 having column stability and excellent optical properties can be obtained. Can be formed.

  In the above description, after the alignment film composition is applied to the substrate 11 in the alignment film forming unit 32, the first exposure unit 33 and the second exposure unit 34 respectively use masks (first masks). 41, the flow of manufacturing the patterned retardation film 1 by forming the stripe-shaped first alignment region and the second alignment region via the second mask 42) is not limited thereto. That is, in the first exposure unit 33 and the second exposure unit 34, the retardation film 1 having the solid alignment film 12 without performing the exposure process without using the mask and forming the alignment film 12 in a pattern shape is obtained. It may be manufactured.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.

<< Manufacture of retardation film >>
[Cleaning treatment for film substrate (pretreatment)]
Using the retardation film manufacturing apparatus 3 schematically shown in FIG. 4 and FIG. 5, the film substrate / alignment film / retardation layer are sequentially processed while conveying a long film substrate made of acrylic resin. Produced a retardation film laminated in this order. That is, in this example, prior to coating the coating liquid made of the alignment film composition on the film substrate, the substrate cleaning unit 30 shown in the schematic diagram of FIG. A cleaning process was performed based on a gravure method in which a predetermined solvent was brought into contact with the gravure roll 62.

  Specifically, the manufacturing examples 1-21 which show the washing | cleaning process conditions in the following Table 1 are implemented, and the base material washing | cleaning part 30 applies to the film base material before coating the coating liquid which consists of alignment film composition. On the other hand, a predetermined solvent was contacted by a gravure method to perform a cleaning process. As the solvent type, a mixed solvent having a ratio of isopropyl alcohol (IPA) and toluene of 50:50, a solvent containing IPA at a ratio of 100%, and a solvent containing toluene at a ratio of 100% are used. Adjusting the line (conveyance) speed [m / min] of the film substrate by the mechanism 61, the contact length L [cm] between the film substrate and the gravure roll 62, and the draw ratio [%], and performing the cleaning treatment did.

[Confirmation of whitening level of film substrate after cleaning]
Appearance inspection was performed on the film substrate thus subjected to the cleaning treatment, and the level of whitening (whitening level) caused by contact with the gravure roll 62 was evaluated in six stages of “1” to “6”. . In the 6-level evaluation, the larger the number, the higher the whitening level.

[Confirmation of the presence of foreign matter on the film substrate surface]
In addition, the presence of foreign substances such as proteins attached to the surface of the film substrate after the cleaning treatment was visually confirmed.

[Production of retardation film (lamination of alignment film and retardation layer)]
After performing the washing treatment as described above, an alignment film was formed on the film substrate. That is, an alignment film composition is prepared by dissolving 100 parts by mass of a photo-alignment material (trade name: ROP-103, manufactured by Lorick Co., Ltd.) having both a photodimerization site and a thermal crosslinking site in 900 parts by mass of methyl ethyl ketone (MEK). Then, the prepared alignment film composition was applied to a film substrate made of an acrylic resin subjected to a cleaning treatment by a die coating method so that the film thickness after curing was 200 nm. And it was made to flow for 2 minutes in the dryer adjusted to 100 degreeC, the solvent was evaporated, and the composition was thermoset. Subsequently, a striped pattern having a width of 500 μm is applied to the thin film in a direction parallel to the transport direction of the original fabric by applying polarized ultraviolet light (polarization axis is 45 ° with respect to the transport direction of the film) through a wire grid. Then, irradiation was performed through a mask formed on synthetic quartz. Subsequently, polarized ultraviolet rays (with a polarization axis of −45 ° with respect to the film transport direction) that passed through a wire grid without passing through a mask were irradiated. As the ultraviolet irradiation device, “H bulb” (manufactured by Fusion) was used. The wavelength of polarized ultraviolet light was 313 nm, and the integrated light quantity was 40 mJ / cm ² . The integrated light quantity was measured using an ultraviolet light quantity meter “UV-351” (manufactured by Oak Manufacturing Co., Ltd.).

Subsequently, on the formed alignment film (pattern alignment film), a polymerizable liquid crystal composition (product name: licrivue (registered trademark) RMS03-013C, manufactured by Merck & Co., Inc.) was applied by a die coating method to a coating amount of 3.6 g / It was coated as m ^2. Then, it flows for 1 minute in the first dryer adjusted to 60 ° C., 0.5 minute in the second dryer adjusted to 95 ° C., and 0.5 minute in the third dryer adjusted to 105 ° C., and is cooled to near room temperature. After that, a retardation layer (liquid crystal layer) is formed by irradiating ultraviolet rays with a wavelength of 260 nm using an ultraviolet irradiating device of the same type as the above-described ultraviolet irradiating device until the integrated light quantity becomes 300 mJ / cm ^2. Got.

[Evaluation of occurrence of repelling]
With respect to the obtained retardation film, the presence or absence of repelling in the alignment film and the retardation layer was observed using an optical microscope.

[Evaluation of orientation]
For the obtained retardation film, using an optical axis measuring device Imaging Mueller Matrix Polarimeter (manufactured by Axometrics), the orientation is σ value (standard deviation of optical axis variation) every 3.4 mm × 2.7 mm. And the orientation of the retardation film was evaluated. With regard to the orientation, those having a σ value of less than 0.5 are evaluated as “◯”, those having a σ value of 0.5 or more and less than 1 are evaluated as “Δ”, and those having a σ value of 1 or more are evaluated as “×”. did.

≪Evaluation≫
Table 1 below collectively shows the cleaning treatment conditions for the film base material, the appearance inspection after the washing treatment, the presence of foreign matter, and the evaluation results for the orientation of the retardation film.

  As is apparent from the results shown in Table 1, the film substrate before coating the alignment film composition is subjected to a cleaning treatment by bringing a solvent containing isopropyl alcohol into contact with the gravure roll 62 to thereby obtain the film. Foreign substances such as proteins adhering to the substrate surface could be effectively removed, and repelling in the alignment film and retardation layer could be suppressed.

  On the other hand, when a solvent containing toluene at a ratio of 100% was used (Production Example 21), foreign matters could not be removed effectively and repelling occurred.

  In addition, from the results of adjusting the line speed, the contact length L, and the draw ratio, the degree of contact between the film substrate and the gravure roll 62 is appropriately controlled from the viewpoint of exhibiting good orientation in the retardation film. Was found to be preferable.

DESCRIPTION OF SYMBOLS 1 Retardation film 2 Optical film 3 Retardation film manufacturing apparatus 11 Film base material (base material)
DESCRIPTION OF SYMBOLS 12 Alignment film 13 Retardation layer 20 Adhesive layer 21 Polarizer 30 Base material washing | cleaning part 31 Base material provision part 32 Alignment film formation part 33 1st exposure part 34 2nd exposure part 35 Composition coating part for retardation layer formation 36 retardation layer forming part 61 transport roll mechanism 62 gravure roll

Claims (7)

A process for producing a retardation film obtained by sequentially laminating an alignment film and a retardation layer on the film substrate by sequentially processing while conveying a long film substrate,
Before coating an alignment film composition for forming an alignment film, the film substrate is washed by bringing a solvent containing isopropyl alcohol into contact with a gravure roll. Production method.   The method for producing a retardation film according to claim 1, wherein the film substrate is made of an acrylic resin.   The method for producing a retardation film according to claim 1, wherein the solvent is a mixed solvent of isopropyl alcohol and toluene.   The said mixed solvent contains isopropyl alcohol in the ratio of 50 mass% or more, The manufacturing method of the retardation film of Claim 3 characterized by the above-mentioned.   The method for producing a retardation film according to any one of claims 1 to 4, wherein the film substrate is transported at a transport speed of 10 m / min to 50 m / min with respect to the gravure roll.   The method for producing a retardation film according to claim 1, wherein a contact length between the gravure roll and the film base is 2 cm to 10 cm. The method for producing a retardation film according to claim 1, wherein the draw ratio is 50% to 150%.

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