JP2014010178A - Evaluation method for alignment layer for retardation film and method for manufacturing retardation film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaluation method for an alignment layer for a retardation film, by which an alignment regulation force of an alignment layer for a liquid crystal can be preliminarily and easily evaluated, and a method for manufacturing a retardation film using the evaluation method, by which a retardation film having excellent aligning property of a liquid crystal layer can be manufactured.SOLUTION: The valuation method for an alignment layer 1 for a retardation film includes: a step of applying a curable composition for an alignment layer containing a photo-aligning compound on one surface side of a triacetylcellulose substrate 10 containing a phosphate, drying and irradiating the composition with light to form an impregnated layer 30 where the triacetylcellulose substrate 10 is impregnated with the photo-aligning compound, and an alignment layer 20; a step of, after the alignment layer 20 is formed, measuring ions derived from the phosphate on the surface of the alignment layer 20 by use of a TOF-SIMS (time-of-flight secondary ion mass spectrometer); and a step of evaluating whether the phosphate amount on the surface of the alignment layer 30 is permissible or not, based on the measurement results.

Description

  The present invention relates to a method for evaluating an alignment film for a retardation film and a method for producing a retardation film.

Conventionally, in a liquid crystal display device, various techniques have been developed in order to improve the problem of viewing angle dependency. As one of them, a retardation film having a retardation layer exhibiting birefringence is used as a liquid crystal cell. Liquid crystal display devices disposed between polarizing plates are known (for example, Patent Documents 1 and 2).
As the retardation film having the retardation layer, an alignment film having an alignment regulating force for aligning a liquid crystal material in a certain direction on a resin substrate, and a liquid crystal formed on the alignment film and arranged in a certain direction. What has a phase difference layer containing a material is used.

  Conventionally, as a flat panel display, a two-dimensional display has been mainstream, but in recent years, a flat panel display capable of three-dimensional display has begun to attract attention. Further, in future flat panel displays, it is a natural tendency to be capable of three-dimensional display, and flat panel displays capable of three-dimensional display are being studied in a wide range of fields.

In order to perform three-dimensional display on a flat panel display, it is usually necessary to display a right-eye video and a left-eye video separately to the viewer in some manner. As a method for separately displaying the right-eye video and the left-eye video, for example, a passive method is known. Such a passive three-dimensional display method will be described with reference to the drawings. FIG. 4 is a schematic diagram illustrating an example of a passive three-dimensional display. As shown in FIG. 4, in this method, first, the pixels constituting the flat panel display are classified into two types of pixels, a right-eye video display pixel and a left-eye video display pixel, and the right-eye pixel is displayed in the display display area. The pixels are arranged in a pattern so that the left-eye pixels are adjacent to each other. One group of pixels displays a right-eye image, and the other group of pixels displays a left-eye image. In addition, a linear polarizing plate and a pattern retardation film (hereinafter, simply referred to as a pattern retardation film) in which a pattern retardation layer corresponding to the arrangement pattern of the pixel is formed are used for the right eye. The image and the image for the left eye are converted into circularly polarized light that is orthogonal to each other. In addition, the viewer wears circular polarizing glasses that employ circular polarizing lenses that are orthogonal to each other for the right-eye lens and the left-eye lens, so that the right-eye image passes only through the right-eye lens and the left-eye image is displayed. Pass only through the lens for the left eye. In this way, the right-eye video reaches only the right eye, and the left-eye video reaches only the left eye, thereby enabling three-dimensional display.
Such a passive method has an advantage that three-dimensional display can be easily performed by using the pattern retardation film and the corresponding circular polarizing glasses.

  As the above-mentioned pattern retardation film, for example, in Patent Document 3, a photo-alignment film in which an alignment regulating force is controlled in a pattern shape on a glass substrate, and an alignment of a liquid crystal material formed on the photo-alignment film, A pattern retardation plate having a retardation layer (liquid crystal layer) regulated to follow the pattern of the alignment film is disclosed.

As described above, in each of the retardation films, the liquid crystal material is arranged in a certain direction by the alignment film, and the optical axis is required to be constant throughout the film or in each pattern in the film.
The retardation layer (liquid crystal layer) has insufficient alignment properties when the alignment regulating force of the alignment film is weak, and a sufficient retardation cannot be obtained. For example, a good three-dimensional image is obtained in a patterned retardation film. There is a problem that it cannot be displayed. In order for the retardation layer (liquid crystal layer) to obtain an appropriate retardation, it is important that the alignment film sufficiently draws out the orientation of the liquid crystal.

JP-A-3-67219 JP-A-4-322223 JP 2005-49865 A

When preparing a retardation film using a triacetyl cellulose base material, the inventors prepared an alignment layer and at the same time provided an infiltration layer in which the alignment layer component penetrated the triacetyl cellulose base material. It was conceived to improve the adhesion of the layer to the substrate. However, in some cases, the adhesion is not improved and the orientation of the liquid crystal layer is disturbed. If the orientation of the liquid crystal layer is disturbed, a sufficient phase difference cannot be obtained, which affects display characteristics.
However, it has been unclear when the orientation of the liquid crystal layer is disturbed. Further, it is difficult to evaluate the alignment regulating force of the alignment film for retardation film by forming a liquid crystal layer each time, and the evaluation method can easily evaluate the alignment property of the liquid crystal layer of the retardation film in advance. Was demanded.

  The present invention has been made in view of the above circumstances, and uses a triacetyl cellulose base material containing a phosphate ester as a plasticizer, and a permeation layer formed by infiltrating an alignment layer component into the triacetyl cellulose base material. The method for evaluating an alignment film for retardation film, in which the alignment regulating force of the liquid crystal layer of the retardation film can be easily evaluated in advance when the alignment film for retardation film having the alignment layer laminated thereon is produced, and the evaluation It aims at providing the manufacturing method of the phase difference film which can manufacture the phase difference film excellent in the orientation of a liquid crystal layer by using the method.

As a result of intensive studies to achieve the above object, the present inventors have found a correlation between the amount of phosphate ester present on the surface of the alignment film for retardation film and the orientation of the liquid crystal layer of the retardation film. I got the knowledge that there is. The phosphate ester is included as a plasticizer in the triacetyl cellulose base material.
The present invention has been completed based on such knowledge.

The evaluation method for an alignment film for retardation film according to the present invention is an evaluation method for an alignment film for retardation film in which an alignment layer is provided in this order via a permeation layer on one side of a triacetyl cellulose substrate. And
By applying a curable composition for an alignment layer containing a photoalignment compound on one side of a triacetylcellulose substrate containing a phosphate ester, drying, and light irradiation, A step of forming an infiltration layer into which the photoalignment compound has infiltrated, and an alignment layer;
After forming the alignment layer, a step of measuring ions derived from phosphate ester on the surface of the alignment layer with a time-of-flight secondary ion mass spectrometer (TOF-SIMS);
And a step of evaluating whether or not the amount of phosphate ester on the surface of the alignment layer is allowed based on the result of the measurement.

The method for producing a retardation film according to the present invention is a method for producing a retardation film in which an alignment layer and a retardation layer are provided in this order on one side of a triacetyl cellulose base material via a permeation layer. ,
By applying a curable composition for an alignment layer containing a photoalignment compound on one side of a triacetylcellulose substrate containing a phosphate ester, drying, and light irradiation, A step of forming an infiltration layer into which the photoalignment compound has infiltrated, and an alignment layer;
After forming the alignment layer, a step of measuring ions derived from phosphate ester on the surface of the alignment layer with a time-of-flight secondary ion mass spectrometer (TOF-SIMS);
A determination step of determining whether or not the amount of phosphate ester on the surface of the alignment layer is allowed by comparing the result of the measurement with a predetermined value set in advance,
In the determination step, a curable composition for a retardation layer containing a polymerizable liquid crystal compound is applied onto an alignment layer that is determined to have an acceptable amount of phosphate ester on the surface of the alignment layer, dried, and cured. And a step of forming a retardation layer.

  In the method for producing a retardation film according to the present invention, the curable composition for an alignment layer is applied to one side of the triacetylcellulose substrate, and the thickness of the permeation layer is less than 0.4 μm. It has the process of forming the osmosis | permeation layer which the said photo-alignment compound osmose | permeated to the said triacetyl cellulose base material, and the process of forming an alignment layer by drying by the set drying conditions, and alignment of a liquid crystal, and adhesion | attachment It is preferable from the point which is excellent in property.

  According to the present invention, a phase difference in which a triacetyl cellulose base material containing a phosphate ester as a plasticizer is used, and an alignment layer is laminated through a permeation layer formed by infiltrating a component for alignment layer into the triacetyl cellulose base material. By using the evaluation method of the alignment film for retardation film, which can easily evaluate the alignment regulating force of the liquid crystal of the alignment layer in advance when the alignment film for film is manufactured, The manufacturing method of the retardation film which can manufacture the retardation film excellent in the orientation can be provided.

It is the figure which showed typically an example of the alignment film for retardation films of this invention. It is process drawing which shows an example of the orientation layer formation process in the evaluation method of the orientation film for retardation films of this invention. It is the figure which showed typically an example of the phase difference film of this invention. It is the schematic which shows an example of the liquid crystal display device which can display a three-dimensional image | video with a passive system.

Hereinafter, the evaluation method of the alignment film for retardation films according to the present invention and the manufacturing method of the retardation film will be described in order.
In the present invention, the term “permeability” includes the concept of swelling or wetting the substrate in addition to the property of penetrating the substrate. In the present invention, the osmotic layer refers to a layer in which at least a component of a triacetyl cellulose base material and a photoalignment compound are mixed.
In the present invention, the slow axis and the fast axis are collectively referred to as an optical axis.
In the present invention, the alignment regulating force means an interaction that aligns liquid crystal materials in a specific direction.
In the present invention, the retardation film includes a pattern retardation film unless otherwise specified.
Moreover, in this invention, (meth) acrylate represents a methacrylate and / or a methacrylate.

I. Method for evaluating alignment film for retardation film The method for evaluating an alignment film for a retardation film according to the present invention is a retardation in which an alignment layer is provided in this order via a permeation layer on one side of a triacetylcellulose substrate. A method for evaluating an alignment film for a film, wherein a curable composition for an alignment layer containing a photoalignment compound is applied to one side of a triacetylcellulose substrate containing a phosphate ester, dried, and irradiated with light. Thus, after the formation of the alignment layer, a step of forming a permeation layer in which the photo-alignment compound has penetrated the triacetyl cellulose base material, and an alignment layer (hereinafter sometimes referred to simply as an alignment layer formation step). The step of measuring ions derived from phosphate ester on the surface of the alignment layer with a time-of-flight secondary ion mass spectrometer (TOF-SIMS) (hereinafter sometimes simply referred to as a measurement step) and the measurement. And a step of evaluating whether or not the amount of phosphate ester on the surface of the alignment layer is allowed (hereinafter, simply referred to as an evaluation step).
According to the evaluation method, a triacetyl cellulose base material containing a phosphate ester as a plasticizer is used, and the orientation layer is laminated via a permeation layer obtained by infiltrating the orientation layer component into the triacetyl cellulose base material. When the alignment film for retardation film is produced, the alignment regulating force of the liquid crystal of the alignment layer can be easily evaluated in advance.

Such an evaluation method of the alignment film for retardation film of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the alignment film 1 for retardation film of the present invention has an alignment layer 20 provided in this order on a triacetyl cellulose base material 10 with a permeation layer 30 interposed therebetween.
FIG. 2 is a process diagram showing an example of an alignment layer forming process in the method for evaluating an alignment film for retardation film of the present invention.
First, as shown to FIG. 2 (A), the curable composition for alignment layers containing a photo-alignment compound is apply | coated to the one surface side of the triacetyl cellulose base material 10 containing phosphate ester, and the coating film 70 is formed. . Next, as shown in FIG. 2B, the coating film 70 is dried to obtain a dried coating film 80. At this time, the solvent and the photoalignment compound contained in the alignment layer curable composition penetrate into the triacetylcellulose substrate 10, thereby forming a region 90 in which the solvent and the photoalignment compound are infiltrated. Next, as shown in FIG. 2C, by performing light irradiation 100 from the side where the alignment layer 20 is provided, the dried coating film 80 is photo-aligned and cured simultaneously, so that the alignment layer 20 is formed. At the same time, the permeable layer 30 in which the photoalignable compound has penetrated the triacetyl cellulose base material 10 is formed.
Next, after forming the alignment layer, a time-of-flight secondary ion mass spectrometer (for a retardation film provided with an alignment layer on one surface side of a triacetyl cellulose substrate via a permeation layer (time-of-flight secondary ion mass spectrometer) In TOF-SIMS), ions derived from phosphate ester on the surface of the alignment layer are measured. And based on the measurement result of the ion derived from the said phosphate ester, it is evaluated whether the phosphate ester amount of the said orientation layer surface is accept | permitted.

Manufactures an alignment film for retardation films using a triacetyl cellulose base material containing a phosphate ester as a plasticizer and laminating the alignment layer through a permeation layer in which the alignment layer component is infiltrated into the triacetyl cellulose base material In contrast, the present inventors have found that the alignment layer for the retardation film is present on the surface of the alignment film for the problem that the orientation of the alignment layer is not improved and the alignment of the liquid crystal layer may be disturbed. The present inventors have found that there is a correlation between the amount of phosphate ester and the orientation and adhesion of the liquid crystal layer of the retardation film.
Since the triacetyl cellulose base material is usually formed by a solution casting method, a plasticizer is blended in the raw material solution in order to obtain flexibility as a film, and phosphate ester is used as the plasticizer. In many cases. Therefore, the phosphate ester present on the surface of the alignment film for retardation film is derived from a triacetyl cellulose base material.
When a curable composition for an alignment layer containing a photoalignment compound is applied to one side of a triacetylcellulose substrate containing a phosphate ester and dried, the solvent and light contained in the curable composition for an alignment layer are dried. While the orientation compound penetrates into the triacetyl cellulose base material, it is presumed that the phosphate ester contained in the triacetyl cellulose base material is mixed into the orientation layer. And it is estimated that a part of the mixed phosphate ester bleeds out to the alignment layer surface during drying. It is estimated that the phosphoric acid ester present on the surface of the alignment layer becomes a foreign substance when the liquid crystal layer is aligned and inhibits the alignment of the liquid crystal. And it is estimated that the greater the amount of phosphate ester present on the surface of the alignment layer, the more the liquid crystal alignment is inhibited.
Therefore, it is estimated that there is a correlation between the evaluation of the amount of phosphate ester present on the surface of the alignment layer and the orientation of the liquid crystal. Therefore, in the present invention, by simply measuring the amount of phosphate ester present on the alignment layer surface of the alignment film for retardation film, the liquid crystal of the retardation film is based on the amount of phosphate ester. Can be easily evaluated.
Moreover, when the said evaluation method was used, it turned out that the adhesiveness of a base material and an orientation layer can also be evaluated. This indicates that the more phosphate ester present on the alignment layer surface, the more the solvent and photoalignment compound penetrated into the triacetylcellulose substrate, and in this case, the adhesion tends to deteriorate. It was issued. Therefore, if the said manufacturing method is used, adhesiveness is favorable and the retardation film excellent in the orientation of a liquid crystal layer can be manufactured.

The evaluation method of the present invention includes at least an alignment layer forming step, a measurement step, and an evaluation step, and may include other steps as necessary.
Hereafter, each process of the evaluation method of such this invention is demonstrated in order.

<Alignment layer formation process>
In the alignment layer forming step, the triacetyl cellulose base material containing a phosphate ester is coated on one surface side with a curable composition for alignment layer containing a photoalignment compound, dried, and irradiated with light. This is a step of forming an osmosis layer in which the photo-alignment compound has penetrated into an acetylcellulose substrate, and an alignment layer.
This will be described in order below.

(Triacetyl cellulose base material)
The triacetyl cellulose base material (hereinafter sometimes referred to as “TAC base material”) used in the present invention is characterized by containing a phosphate ester as a plasticizer. If it is a TAC substrate containing a phosphate ester, a known TAC substrate used for the retardation film may be appropriately selected and used.

  Examples of the phosphate ester used as the plasticizer include known phosphate esters as the plasticizer, such as triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, tri-n-butyl phosphate, and tris phosphate. (Butoxyethyl), tris (2-chloroethyl) phosphate and the like.

  The thickness of the TAC substrate may be set as appropriate. Usually, it exists in the range of 20 micrometers-200 micrometers, and it is preferable that it exists in the range of 30 micrometers-90 micrometers.

(Orientation layer)
The alignment layer is a layer having an alignment regulating force and for aligning the liquid crystal material contained in the retardation layer curable composition in a certain direction.

In the present invention, the alignment layer is formed using a curable composition for alignment layer containing a photoalignment compound. The composition of the curable composition for the alignment layer is not particularly limited as long as the photo-alignment compound is included, and is appropriately selected depending on the combination with a means for imparting alignment regulating force. In the present invention, the curability refers to a property that becomes hard through a chemical reaction. The curable composition usually contains a compound having a reactive group. Examples of the reactive group include a photodimerization reactive group, a polymerizable functional group, and a thermosetting functional group.
Since the alignment layer of the present invention contains a photoalignment compound, the alignment regulating force is imparted by a photoalignment method.

  Examples of the photo-alignment compound include a polymer having cinnamate, coumarin, benzylidenephthalimidine, benzylideneacetophenone, diphenylacetylene, stilbazole, uracil, quinolinone, maleimide, or a cinnamylideneacetic acid derivative. Among them, a polymer having at least one of cinnamate or coumarin, a polymer having cinnamate and coumarin are preferably used. Examples thereof include compounds described in JP-A-9-118717, JP-T-10-506420, JP-T2003-505561, and WO2010 / 150748.

  The curable composition for alignment layer may contain a compound other than the photo-alignment material as necessary. Such a compound is not particularly limited as long as it does not impair the alignment regulating force of the alignment layer. For example, a monomer or oligomer having a polymerizable functional group (hereinafter sometimes simply referred to as a polymerizable monomer or a polymerizable oligomer) is preferably used.

  Examples of the polymerizable monomer or polymerizable oligomer used in the present invention include a monofunctional monomer having an acrylate polymerizable functional group (for example, ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, N-vinylpyrrolidone) and polyfunctional monomers (for example, polymethylolpropane tri (meth) acrylate, hexanediol (meth) acrylate, triethylene (polypropylene) glycol diacrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) ) Acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl Cold di (meth) acrylate, isocyanuric acid poly (meth) acrylate (for example, isocyanuric acid EO diacrylate)) and bisphenol fluorene derivatives (for example, bisphenoxyethanol full orange (meth) acrylate, bisphenol full orange epoxy (meth) acrylate) Etc. can be used as a single substance or as a mixture.

  The solvent used in the curable composition for alignment layer is usually used to form a permeation layer in which at least the photoalignment compound has penetrated in the region on the alignment layer side of the TAC substrate. Thus, a permeable solvent having permeability is used.

  Examples of the permeable solvent having permeability to the TAC substrate include methyl isobutyl ketone, methyl ethyl ketone, methyl acetate, ethyl acetate, and butyl acetate. Among these, from the viewpoint of permeability, it is preferable to use methyl isobutyl ketone as the permeable solvent.

The solvent may be one type or a combination of two or more types. If the permeable solvent is included so that the curable composition for the alignment layer has permeability to the TAC substrate, another solvent that does not have permeability to the TAC substrate may be included.
Moreover, content of the solvent in the curable composition for alignment layers is 30-70 mass% normally with respect to the whole curable composition for alignment layers, and 35-55 mass% is preferable.

(Application)
The coating method is not particularly limited as long as it can uniformly coat the curable composition for the alignment layer on the surface of the TAC substrate. For example, dip coating, air knife coating, curtain coating Known methods such as a roll coating method, a wire bar coating method, a gravure coating method, a die coating method, a blade coating method, a micro gravure coating method, a spray coating method, and a spin coating method are used.
Moreover, as a coating amount of the curable composition for alignment layers on the TAC substrate, the thickness of the alignment layer to be obtained may be appropriately adjusted so that it is 1 to 1000 nm and 3 to 100 nm. .

(Dry)
After applying by any of the above methods, the solvent contained in the curable composition for the alignment layer is dried. Here, the thickness of the permeation layer can be adjusted by selecting the solid content concentration, the coating solution temperature, the drying temperature, the wind speed of the drying air, the drying time, the solvent atmosphere concentration in the drying zone, and the like. In particular, a method of adjusting the thickness of the osmotic layer by selecting drying conditions is preferable. As the permeation layer is thicker, the amount of phosphate ester on the alignment layer surface tends to increase. Therefore, it is preferable to dry under the drying conditions set so that the thickness of the permeation layer is less than 0.4 μm and further 0.3 μm or less.
Specifically, it is preferable to dry immediately after application while blowing air with a blower or the like. As specific drying temperature, 30 degreeC-120 degreeC is mentioned, for example, and 30-70 degreeC is preferable. Further, the drying wind speed is preferably 0.2 m / s to 50 m / s, and the drying time is suitably adjusted within a range of about 20 seconds to 3 minutes, preferably about 30 seconds to 1 minute.
By controlling the drying temperature, the penetrability of the photo-alignment compound and the solvent into the substrate can be controlled, and accordingly, the amount of phosphate ester on the alignment layer surface can be controlled to some extent.

(Light irradiation)
As shown in FIG. 2C, the light irradiation is preferably performed from the side where the alignment layer 20 is provided, but may be performed from the triacetyl cellulose substrate 10 side.
For light irradiation, ultraviolet rays, visible light, electron beams, ionizing radiation, etc. are mainly used. In the case of ultraviolet curing, ultraviolet rays emitted from light such as an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, and a metal halide lamp are used.
The irradiation amount of the energy beam source may be adjusted as appropriate so that the photo-alignment compound contained in the alignment layer curable composition is aligned and cured so that it can be cured.

(Penetration layer)
As shown in FIG. 2 (C), by applying light irradiation 100, the dried coating film 80 is photo-aligned and cured at the same time, whereby the alignment layer 20 is formed and the triacetyl cellulose substrate 10 is formed. A penetration layer 30 in which the photo-alignment compound has penetrated is formed.
In the permeation layer, the photo-alignment compound of the alignment layer is mixed with the resin of the triacetyl cellulose base material.
The presence of the permeation layer can be confirmed by, for example, an electron micrograph of a cross section of the alignment film for retardation film or the retardation film, mapping by a microscopic IR of the cross section, or a TOF-SIMS method.

In the present invention, the thickness of the osmotic layer is preferably less than 0.4 μm, and more preferably 0.3 μm or less from the viewpoint of the orientation of the liquid crystal and the adhesion between the substrate and the alignment layer.
In addition, the thickness of a osmosis | permeation layer means average layer thickness, for example, can be calculated | required from the electron micrograph of the electron micrograph of the cross section of the orientation film for retardation films or retardation film.

  Moreover, the manufacturing method of the alignment film for pattern retardation films which can manufacture a pattern retardation film can use the method of Unexamined-Japanese-Patent No. 2012-14064, for example.

<Measurement process>
After the alignment layer is formed, ions derived from phosphate ester on the surface of the alignment layer are measured with a time-of-flight secondary ion mass spectrometer (TOF-SIMS).
As a measurement of TOF-SIMS, it can measure on the measurement conditions as described in the Example mentioned later, for example.
The ions derived from the phosphate ester on the surface of the alignment layer preferably detect negative ions.

<Evaluation process>
The evaluation step is a step of evaluating whether or not the amount of phosphate ester on the alignment layer surface is allowed based on the measurement result of the TOF-SIMS measurement.
From the value of ions derived from the phosphate ester determined in the measurement step, the alignment regulating force of the liquid crystal of the alignment layer can be evaluated. Calculate the ratio of the value of the phosphate ester-derived ion obtained in the above measurement step and the value of the total ion or the value derived from the TAC substrate, etc., and the calculated ratio etc. on the surface of the alignment layer From the correlation with the orientation of the liquid crystal when the liquid crystal is applied and aligned, a predetermined value can be appropriately set as an evaluation criterion.
By comparing the ratio calculated from the value of ions derived from phosphate ester obtained by the method for evaluating an alignment film for retardation film according to the present invention with a predetermined value that is a preset evaluation criterion. It can be determined whether or not the phosphate ester amount on the surface of the alignment layer is allowed. The predetermined value to be compared is appropriately set in the same manner as described in the determination step of the manufacturing method described later.
The above description of the method for evaluating the alignment film for retardation film of the present invention also applies to the alignment film for pattern retardation film as it is. In addition, when an alignment film for a patterned retardation film is produced under the same conditions using a curable composition for an alignment layer that constitutes an alignment film for a retardation film that has been determined to have excellent liquid crystal alignment regulating power, The alignment film for a pattern retardation film is also excellent in liquid crystal alignment regulating power.

II. Manufacturing method of retardation film The manufacturing method of the retardation film according to the present invention is a retardation film in which an orientation layer and a retardation layer are provided in this order on one surface side of a triacetyl cellulose substrate via a permeation layer. A manufacturing method of
By applying a curable composition for an alignment layer containing a photoalignment compound on one side of a triacetylcellulose substrate containing a phosphate ester, drying, and light irradiation, A permeation layer into which the photoalignment compound has permeated, and a step of forming the alignment layer (alignment layer forming step);
After forming the alignment layer, a step (measurement step) of measuring ions derived from phosphate ester on the surface of the alignment layer with a time-of-flight secondary ion mass spectrometer (TOF-SIMS);
A determination step of determining whether or not the amount of phosphate ester on the surface of the alignment layer is allowed by comparing the result of the measurement with a predetermined value set in advance,
In the determination step, a curable composition for a retardation layer containing a polymerizable liquid crystal compound is applied onto an alignment layer that is determined to have an acceptable amount of phosphate ester on the surface of the alignment layer, dried, and cured. And a step of forming a retardation layer (retardation layer forming step).

As shown in FIG. 3, the phase difference film 2 is a film in which an alignment layer 20 and a phase difference layer 40 are provided in this order on one surface side of a triacetyl cellulose substrate 10 with a permeation layer 30 interposed therebetween. And may have other layers.
According to the production method of the present invention, a retardation film excellent in liquid crystal orientation is produced by measuring ions derived from phosphate ester on the surface of the alignment layer and comparing the measurement result with a predetermined value set in advance. can do.
The production method of the present invention includes at least the alignment layer formation step, the measurement step, the determination step, and the retardation layer formation step, and may include other steps as necessary. is there.
Hereinafter, the manufacturing method of the present invention will be described. However, the alignment layer forming step and the measuring step are steps common to the evaluation method of the alignment film for retardation film according to the present invention. Since it is the same, description here is abbreviate | omitted.

<Judgment process>
Whether the determination step allows the phosphate ester amount on the alignment layer surface by comparing the result of ion measurement derived from the phosphate ester on the alignment layer surface in the measurement step with a predetermined value set in advance. It is the process of determining.
The predetermined value may be set appropriately as a numerical value capable of determining whether or not the liquid crystal alignment regulating force is excellent. For example, the alignment layer is manufactured by the same method as the evaluation method according to the present invention, using several alignment films for retardation films manufactured by the same manufacturing method as some retardation films that allow liquid crystal alignment. Measure ions derived from phosphate ester on the surface, and calculate the ratio of the normalized value, for example, the value of ions derived from phosphate ester and the value of total ions or the value derived from TAC substrate, etc. Based on these, the predetermined value can be determined. The value of the predetermined value is not particularly limited. For example, TOF-SIMS measurement is performed under the same measurement conditions as described in the Examples, and in negative ion analysis, PO2, PO3, C9H14PO derived from triphenyl phosphate with respect to the total normalized strength (T) of negative ions, The ratio (P / T) of the total normalized strength (P) of C12H10PO4 and C18H14PO4 can be set to 0.02 or less. In addition, the said normalization intensity | strength shall obtain | require the normalization intensity | strength of each fragment as [peak area of each fragment] / [total ion amount] x10000.

  For example, as a result of comparing the value calculated in the same manner as the predetermined value with the predetermined value based on the measurement result of the measurement step, if the calculated value is equal to or less than the predetermined value, the alignment layer It is determined that the amount of phosphate ester on the surface is acceptable, and this is used in the next step of forming the retardation layer. On the other hand, when it is determined that the amount of phosphate ester on the surface of the alignment layer is unacceptable, it is not used in the retardation layer forming step.

<Phase difference layer forming step>
In the retardation layer forming step, a curable composition for a retardation layer containing a polymerizable liquid crystal compound is applied on the alignment layer determined to allow the amount of phosphate ester on the alignment layer surface in the determination step. It is a step of forming a retardation layer by drying and curing.
The retardation layer is a layer made of a cured product of a curable composition for retardation layer containing a polymerizable liquid crystal compound, and a liquid crystal material is arranged in a certain direction by the alignment layer.
The curable composition for a retardation layer contains at least a polymerizable liquid crystal compound and may contain other components.

  The polymerizable liquid crystal compound has a polymerizable functional group in the liquid crystal molecule, and can be cross-linked between the liquid crystal molecules by the action of a radical generated from the photopolymerization initiator by irradiation of light or an electron beam. Stability of the retardation film is improved. Examples thereof include nematic liquid crystalline molecular materials, cholesteric liquid crystalline molecular materials, chiral nematic liquid crystalline molecular materials, smectic liquid crystalline molecular materials, and discotic liquid crystalline molecular materials having a polymerizable group.

  The method for forming the retardation layer is not particularly limited as long as it can accurately coat a retardation layer having a desired thickness. About the method of application | coating, drying, and hardening, the method similar to having demonstrated at the said orientation layer formation process can be used.

  Although the thickness of a phase difference layer is not specifically limited, For example, it can set within the range of 1 nm-2000 nm, Preferably, it is 500 nm-1000 nm.

  Hereinafter, the present invention will be specifically described with reference to examples. These descriptions do not limit the present invention.

(Example 1: Evaluation of alignment film for retardation film)
(1) Production of Alignment Film 1 for Retardation Film On one side of a triacetylcellulose (TAC) substrate (thickness 60 μm) containing triphenyl phosphate, polyvinyl cinnamate as a photoalignment compound and PGME (propylene as a solvent) Immediately after applying the alignment layer-containing curable composition containing glycol monomethyl ether), it was dried in an oven at 120 ° C. for 2 minutes while applying air at a wind speed of 5 m / sec with a blower. Next, the alignment layer was photo-aligned and cured by light irradiation to form a permeation layer and an alignment layer, thereby obtaining an alignment film 1 for retardation film.
When measured with a white interferometer, the thickness of the permeation layer was less than 100 nm.

(2) TOF-SIMS measurement The alignment film 1 for retardation film obtained above was subjected to TOF-SIMS measurement under the following conditions.
<TOF-SIMS measurement conditions>
Device name: Time-of-flight secondary ion mass spectrometer (manufactured by ION-TOF, model: TOF-SIMS5)
Primary ion species: Bi3 ++
Primary ion acceleration voltage: 25 kV
Primary ion current value: 0.2 pA
Frequency: 10kHz
Measurement area: 500μm × 500μm
Scan: 128 pixels x 128 pixels x 64 scans Charging correction: Electronic irradiation

(3) Evaluation process
About the measurement result of said TOF-SIMS, it normalized from the secondary ion mass and the total ion amount.
Normalized intensity: [peak area of each fragment] / [total ion amount] × 10000
In the negative ion analysis, the ratio (P / T) of the total normalized strength (P) of PO2, PO3, C9H14PO, C12H10PO4 and C18H14PO4 derived from triphenyl phosphate to the total normalized strength (T) of negative ions is obtained. It was. The results are shown in Table 1. As a result, it was judged that P / T was 0.018, and the amount of triphenyl phosphate was small and acceptable.

(Example 2: Evaluation of alignment film for retardation film)
(1) Manufacture of alignment film 2 for retardation film Curing for alignment layer containing polyvinyl cinnamate as a photoalignment compound on one side of a triacetyl cellulose (TAC) substrate (thickness 60 μm) containing triphenyl phosphate The composition was applied with a blower without applying air, and then dried in an oven at 120 ° C. for 2 minutes. Next, the alignment layer was photo-aligned and cured by light irradiation to form a permeation layer and an alignment layer, and an alignment film 2 for retardation film was obtained.
When measured with a white interferometer, the thickness of the permeation layer was 400 nm.

(2) TOF-SIMS measurement In the same manner as in Example 1, TOF-SIMS measurement was performed.
(3) Evaluation step In the same manner as in Example 1, the measurement results of TOF-SIMS were evaluated. In the negative ion analysis, the ratio (P / T) of the total normalized strength (P) of PO2, PO3, C9H14PO, C12H10PO4 and C18H14PO4 derived from triphenyl phosphate to the total normalized strength (T) of negative ions is obtained. It was. The results are shown in Table 1. As a result, it was judged that P / T was 0.038, which was an unacceptable amount due to a large amount of triphenyl phosphate.

(Example 3: Production of retardation film)
From Examples 1 and 2, in the negative ion analysis, the ratio (P / T) of the total normalized strength (P) derived from triphenyl phosphate to the total normalized strength (T) of negative ions is 0.020 or less. If so, a predetermined value was set to be an allowable amount.
In the alignment film 1 for retardation film having P / T of 0.018, it was determined that the amount of phosphate ester on the surface of the alignment layer was allowed.
Using the alignment film for retardation film 1, a curable composition for retardation layer containing a polymerizable liquid crystal compound (nematic liquid crystal) is applied on the alignment layer, dried, and cured by light irradiation. A retardation layer was formed to obtain a retardation film 1.

(Comparative Example 1: Production of retardation film)
The alignment film 1 for retardation film having P / T of 0.038 was determined to have an unacceptable amount of phosphate ester on the surface of the alignment layer.
Using the alignment film 2 for retardation film, apply | coat the curable composition for retardation layers containing a polymeric liquid crystal compound on the said alignment layer similarly to Example 3, dry, and light-irradiate. Was cured to form a retardation layer, and a comparative retardation film 1 was obtained.

(Verification of evaluation)
(1) Evaluation of liquid crystal orientation About the phase difference film 1 obtained in Example 3, and the comparison phase difference film 1 obtained by the comparative example 1, the liquid crystal orientation of the phase difference layer was evaluated.
As a result, the retardation film 1 obtained in Example 3 had good liquid crystal alignment. On the other hand, the comparative retardation film 1 obtained in Comparative Example 1 had poor liquid crystal alignment.
(2) Evaluation of adhesiveness About the retardation film 1 obtained in Example 3 and the comparative retardation film 1 obtained in Comparative Example 1, a cross cut was made on the surface of the retardation layer at 10 × 10 squares. Adhesion was evaluated with a ding tape. Evaluation was made to display brightly under crossed Nicols after tape peeling, and the liquid crystal missing part (dark part) in the crosscut was measured.
As a result, in the retardation film 1 obtained in Example 3, 100 squares out of 100 squares were not peeled off, and the adhesion was good. On the other hand, in the comparative retardation film 1 obtained in Comparative Example 1, 100 squares were peeled from 100 squares, and the adhesion was poor.

(Example 4: Production of pattern retardation film)
A patterned retardation film was produced by the method described in Example 1 of JP2012-014064. On one side of a triacetylcellulose (TAC) substrate (trade name Fujitac, manufactured by Fuji Film Co., Ltd., thickness 60 μm) containing a long triphenyl phosphate, the same curability for alignment layer as in Example 1 of the present application The composition was applied and dried under the same drying conditions as Example 1 to prepare an irradiated substrate. Subsequently, the penetration layer and the alignment layer were formed by photo-aligning and curing the alignment layer by light irradiation.
Subsequently, when the ions derived from the phosphate ester on the surface of the alignment layer were measured and evaluated by TOF-SIMS in the same manner as in Example 1 of the present application, the P / T was 0.020 or less.
On the alignment layer, a curable composition for a retardation layer containing the same polymerizable liquid crystal compound as in Example 3 of the present application is applied, dried, and cured by light irradiation to form a retardation layer. A retardation film 2 was obtained.

DESCRIPTION OF SYMBOLS 1 Alignment film for retardation films 10 Triacetyl cellulose base material 20 Alignment layer 30 Penetration layer 70 Coating film 80 Dry coating film 90 The area | region which the solvent and photoalignment compound are osmose | permeating 100 Light irradiation

Claims (3)

A method for producing a retardation film in which an orientation layer and a retardation layer are provided in this order on one surface side of a triacetylcellulose substrate via a permeation layer,
By applying a curable composition for an alignment layer containing a photoalignment compound on one side of a triacetylcellulose substrate containing a phosphate ester, drying, and light irradiation, A step of forming an infiltration layer into which the photoalignment compound has infiltrated, and an alignment layer;
After forming the alignment layer, a step of measuring ions derived from phosphate ester on the surface of the alignment layer with a time-of-flight secondary ion mass spectrometer (TOF-SIMS);
A determination step of determining whether or not the amount of phosphate ester on the surface of the alignment layer is allowed by comparing the result of the measurement with a predetermined value set in advance,
In the determination step, a curable composition for a retardation layer containing a polymerizable liquid crystal compound is applied onto an alignment layer that is determined to have an acceptable amount of phosphate ester on the surface of the alignment layer, dried, and cured. And a step of forming a retardation layer. A method for producing a retardation film.   On one side of the triacetylcellulose substrate, the orientation layer curable composition is applied, dried under drying conditions set so that the thickness of the permeation layer is less than 0.4 μm, and irradiated with light. 2. The method for producing a retardation film according to claim 1, comprising a step of forming a permeation layer in which the photo-alignment compound has permeated into the triacetyl cellulose base material, and an orientation layer. An evaluation method of an alignment film for a retardation film in which an alignment layer is provided in this order via a permeation layer on one side of a triacetyl cellulose substrate,
By applying a curable composition for an alignment layer containing a photoalignment compound on one side of a triacetylcellulose substrate containing a phosphate ester, drying, and light irradiation, A step of forming an infiltration layer into which the photoalignment compound has infiltrated, and an alignment layer;
After forming the alignment layer, a step of measuring ions derived from phosphate ester on the surface of the alignment layer with a time-of-flight secondary ion mass spectrometer (TOF-SIMS);
And a step of evaluating whether or not the amount of phosphate ester on the surface of the alignment layer is allowed based on the result of the measurement, the method for evaluating an alignment film for retardation film.