JP3320904B2 - Laminated body with improved polarization characteristics and release film therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate having improved polarization characteristics and a release film which can be used therefor. More specifically, a polarizing plate, a retardation polarizing plate or a laminate having a structure in which an adhesive layer is provided on one surface of a retardation plate and a release film is laminated on the surface of the adhesive layer, and has excellent polarization characteristics. Also, the present invention relates to a laminate capable of easily performing visual foreign matter inspection and a release film usable therefor.

[0002]

2. Description of the Related Art In recent years, liquid crystal displays (LCD) have been
For example, notebook personal computers and word processors, because of the advancement of technologies for higher performance, higher image quality, higher color, and larger screen, and lighter and lower energy consumption than CRT (Cathode Ray Tube) displays It has been widely adopted for displays and has rapidly spread, and its growth is remarkable.

However, for further growth of liquid crystal displays (LCDs), cost rationalization in terms of price is an important point. Therefore, especially large screen TFT
(ThinFilm Transistor active matrix) and STN (super twisted nematic) methods have a high reject rate, and there is an urgent need to rationalize costs by improving yield.

In a liquid crystal display (LCD), a polarizing plate, a retardation polarizing plate, and a retardation plate are necessary and important components for imparting light and darkness of transmitted light of the LCD and changing a hue. Also, maintaining stable quality has become an important issue, and the standards for process inspection, quality inspection, and shipping inspection are becoming increasingly strict at present.

[0005] The polarizing plate, the retardation polarizing plate and the retardation plate
An adhesive layer is provided on one side of the polarizing substrate, and a release film is laminated on the adhesive layer. Each roll in a roll state is punched and cut into various sizes and provided for an LCD. One of the important items is the inspection of foreign matter contamination and adhesion. This includes not only the manufacturing process of polarizer polarizer but also the process of adhesive lamination with release film, punching and cutting process, and curing and packing process. It is important to control foreign substances in all processes up to this point.

However, the foreign substance inspection in the final inspection step is visually inspected by a human using the cross Nicol method (which is the same as the method of observing with a transmitted light, in which two polarizing plates are stretched at right angles to each other and a peeling film is interposed therebetween). Inspection, especially for large screen, accurate visual inspection may be hindered due to the optical anisotropy of the biaxially oriented aromatic polyester film that is the base of the release film, Oversight of foreign matter has occurred at a considerable frequency.

[0007]

The biaxially oriented aromatic polyester film, particularly the biaxially oriented polyethylene terephthalate film, as the base of the release film, has mechanical and thermal properties that are both longitudinal and transverse during film formation. Those that are balanced in direction are used. The direction of the main axis of the crystal orientation of the film does not coincide with either the longitudinal direction or the lateral direction of the film, and is substantially at the middle of both directions. Furthermore, the direction of the main axis of the crystal orientation greatly changes depending on the position in the lateral direction (width direction) of the film. This change is due to the bowing phenomenon at the time of film formation, and becomes larger as it approaches the both ends than the center.

On the other hand, a polarizing plate, a retardation polarizing plate, and a retardation plate are produced by using a uniaxially oriented polarizing film, and the direction of the orientation axis is usually a longitudinal direction.

Therefore, when a long polarizing plate, a retardation polarizing plate, or a retardation film and a roll-shaped release film are laminated, the orientation axes of both films are displaced, and the crystal orientation in the width direction of the release film. The direction of the main axis gradually changes from the center to the width, and the deviation increases particularly near the both ends. Therefore, in the visual inspection for foreign matter by the crossed Nicols method of the obtained laminate, light interference color occurs, and both ends are changed. The closer to, the greater this degree.

When the width of the laminate is narrow, in other words, L
If the CD is small, the accuracy of the visual foreign matter inspection can be maintained to some extent even if the light interference color is slightly present, but if the width is wide,
In other words, when the LCD has a large screen, it is extremely difficult to check all foreign substances by visual foreign substance inspection.

An object of the present invention is to provide a polarizing plate, a retardation polarizing plate, and the optical interference color does not substantially occur when laminated with the retardation plate, thereby facilitating visual foreign substance inspection by the crossed Nicols method.
Especially for large-screen LCDs, a release film for minimizing oversight of foreign matter as much as possible, thus improving the accuracy of foreign matter inspection and preventing the occurrence of defective products, and laminating the release film with improved polarization characteristics. Is to provide the body.

[0012]

According to the study of the present inventors, the object of the present invention is to provide an adhesive layer on one surface of a polarizing plate, a retardation polarizing plate or a retardation plate, A laminate provided with a release film having a transparent biaxially oriented aromatic polyester film as a base film on the surface,
The biaxially oriented aromatic polyester film has a MOR value of 1.3 to 1.8 measured with a microwave transmission type molecular orientation meter.
And the difference between the minimum and maximum MOR values is 0.2 or less, and the retardation defined by the following equation (1):
The value (R) has at least 1200 (nm);

[Number 3] R = △ n · d ...... ( 1) ( here, △ n is film of visible light (wavelength λ = 589n
m) and the refractive index in the film width direction (nx) and its perpendicular direction
Is the difference (nx-ny) from the refractive index (ny) of the
This is the thickness (nm) of the film. ) Then, the laminate and the direction of the measured orientation main axis of a microwave transparent type molecular orientation meter of the biaxially oriented aromatic polyester film in (1) the releasing film, (2) a polarizing plate, a retardation polarizer Alternatively, this is achieved by a laminate having improved polarization characteristics, wherein the orientation axes of the retardation plates are positioned to be substantially the same or substantially 90 °. Was found.

Further, according to the present invention, there is provided a release film having at least one surface of a transparent biaxially oriented aromatic polyester film subjected to a release property imparting treatment by silicone coating, wherein the biaxially oriented aromatic polyester film is provided. is the difference between the minimum and maximum MOR value measured by a microwave transmission-type molecular orientation meter in the range of 1.3 to 1.8, and MOR values is 0.2 or less, by the following formula (1) Defined resource
The retardation value (R) is at least 1200 (nm)
Having,

[Number 4] R = △ n · d ...... ( 1) ( here, △ n is film of visible light (wavelength λ = 589n
m) and the refractive index in the film width direction (nx) and its perpendicular direction
Is the difference (nx-ny) from the refractive index (ny) of the
This is the thickness (nm) of the film. A) A polarizing plate, a retardation polarizing plate or a release film for inspection of a retardation plate is provided.

The laminate of the present invention having improved polarization characteristics and the release film used therein will be described in more detail. First, the release film will be described, and then the laminate will be described.

In the present invention, as the biaxially oriented aromatic polyester film used as the base film of the release film, for example, a polyethylene terephthalate film or a polyethylene-2,6-naphthalenedicarboxylate film can be preferably mentioned. Of these, a polyethylene terephthalate film is particularly preferred.

The transparent biaxially oriented aromatic polyester film used as the base film of the release film of the present invention has the following MOR (Maximum Oriented Ratio) value of 1.3 as measured by a microwave transmission type molecular orientation meter. ~ 1.8
, Preferably in the range of 1.35 to 1.75.
It is necessary that the MOR values measured at three points in the width direction of the film all satisfy the above range. The point to be measured is the center point in the width direction of the film (the direction perpendicular to the direction of the orientation main axis measured by the microwave transmission type molecular orientation meter) and the end point side connecting the center and both ends of the film. / 5 points, for a total of three places. That is, the MOR values are measured at three points at a distance of 10%, 50%, and 90% from one end of the straight line in the film width direction.

The MOR value is measured at the three locations in the width direction of the film. For the film length direction (perpendicular to the width direction), for example, the film width is 1.0 mm. It is measured at an interval of 2 to 5 times, preferably 2 to 3 times.

Here, the MOR value is a ratio (maximum value / minimum value) of the maximum value and the minimum value of the transmitted microwave intensity measured by the transmission type molecular orientation meter. This MOR value becomes smaller as the difference between the stretching ratio in the longitudinal direction and the transverse direction becomes smaller and the film becomes more balanced, while it becomes larger as the difference becomes larger and the stretching strength in one of the directions becomes stronger. And this MOR
It is not preferable that the value is too small or too large.

This MOR (Maximum Oriented Ratio) value tends to change in the film width direction, and it is preferable that the difference (the difference between the maximum value and the minimum value) at the three locations is 0.2 or less. In particular, it is desirable to be 0.15 or less.

As described above, the base film of the release film of the present invention has a range of the MOR value and a range of the difference between the maximum value and the minimum value satisfying the above-mentioned conditions, and is further defined by the following formula (1). It is necessary that the retardation value (R) is at least 1200 nm.
You .

[0021]

R = △ n · d (1) (where Δn is the visible light of the film (wavelength λ = 589n)
m) is the difference (nx-ny) between the refractive index (nx) in the film width direction and the refractive index (ny) in the direction perpendicular thereto, and d is the thickness (nm) of the film. The biaxially oriented aromatic polyester film is a birefringent body, and when light enters, the incident light propagates as two linearly polarized lights whose vibration planes are orthogonal to each other. The difference between the two linearly polarized lights (ordinary ray and extraordinary ray) is called a phase difference (retardation: R), and this phase difference has an effect as a color and as an interference color in a polarizing plate inspection process.

Michel-Le in orthogonal Nicols
According to the interference color chart (polarized light microscope) of the vy renovation, it is dark field (black) in the low retardation area, and the interference color changes from yellow → red → purple → blue → green in proportion to this retardation, It returns to yellow again and the same cycle is repeated. However, according to the study of the present invention, the density of the interference color sharply decreases when the retardation R exceeds 1200 nm. Therefore, when the retardation R is sufficiently large, the interference color is extremely small, and the visual inspection is performed. Turned out to be an obstacle. Therefore, the optimal range of the optical retardation value (R) is preferably 1200 (nm) or more, and most preferably 1300 in the case of a biaxially oriented aromatic polyester film having a normal film thickness standard of 25 to 50 μm. (Nm) or more was found to be the best as a release film.

As a proof of this requirement, the ratio (I / I ₀ ) of the amount of transmitted light (I) and the amount of incident light (I ₀ ) under crossed Nicols of a transparent plate having birefringence is generally expressed by the following equation (2). ).

[0024]

(I / I ₀ ) = Sin ² (2θ) · Sin ² (π · Δn · d / λ) (2) The ratio between the amount of transmitted light and the amount of incident light in the crossed Nicols of a birefringent transparent plate. The smaller the angle of existence of the birefringent body between Nicols (θ: corresponding to the orientation angle in the present invention), the smaller the extinction position.

Conditions for the extinction position include the following (a) and (b). (A) When θ is small (b) △ nd · λ = R / λ is a natural number 1, 2, 3,...
(R is an integral multiple of the wavelength of the light source: λ) As the orientation angle θ is closer to zero, the ratio of the above equation (2) becomes closer to zero and becomes an extinction position, and the foreign matter emerges white.
The efficiency of visual inspection is most improved. At the same time, the retardation R is preferably a multiple of an average of 590 nm in the visible light wavelength range of 420 nm to 760 nm, and R = 1200 (n
In the case of m), the extinction position can be further increased under the horizontal orientation condition where the orientation angle θ is small, and when the retardation R is larger than that, the light interference density sharply decreases in the interference color chart in the orthogonal Nicols. ≧ 1200 nm is a preferable condition as a foreign matter inspection condition.

Although the upper limit of the retardation R depends on the film thickness, it is not necessary to set the upper limit particularly when the thickness is in the range of 25 μm to 50 μm.

The biaxially oriented aromatic polyester film as the base film preferably has the following characteristics in addition to the above characteristics. (1) Transparency suitable for visual appearance inspection. Flatness to make the adhesive surface uniform. (2) Heat resistance, high strength and high elasticity that can withstand pressure-sensitive adhesive coating and polarizing film lamination performed under high tension heating. Specifically, it must have the following elongation at break, elastic modulus and heat shrinkage.

Film breaking elongation: 150-2 in the longitudinal direction
50% Width direction 50 to 150% Film elastic modulus: Length direction 300 to 700 kg / m
m ² width direction 400 to 800 kg / mm ² film heat shrinkage: 0.4% or less in length direction (110
(° C × 30 minutes) Width direction 0.3% or less (110 ° C. × 30 minutes) (3) Tunneling (fog phenomenon) and curl caused by the occurrence of misalignment with the adhesive interface due to thermal shrinkage of the release film Not dimensional stability. (4) The level of cleanliness used for optical applications (there is no foreign matter, adhering dust, etc. which cause harm). Specifically, a foreign substance existence frequency of 0 to 100/10 inch ² . (5) A thickness of 25 to 50 μm.

The biaxially oriented aromatic polyester film can be produced by the stretching and the method described below. That is, the film is stretched 3 times or more in the machine direction and the transverse direction, respectively, and the stretch ratio in the machine direction is 0.5 or more, more preferably 0.7 or more than the stretch ratio in the transverse direction,
The transverse stretching ratio is 0.5 or more than the longitudinal stretching ratio,
More preferably, it is larger by 0.7 or more.

It is preferable that the stretching ratio in the longitudinal and transverse directions of the film does not exceed 6 times.

The biaxial stretching treatment may be a simultaneous biaxial stretching method or a sequential biaxial stretching method, but the latter is preferred. It is preferable to add isotropic treatment means for reducing bowing in the entire width of the film at the time of heat setting after biaxial stretching. The film after biaxial stretching and heat setting has a heat shrinkage ratio of 4 in both the vertical and horizontal directions when held at 150 ° C. for 30 minutes (no load).
% Is preferable.

In the present invention, the release-imparting treatment applied to at least one surface of the biaxially oriented aromatic polyester film is not particularly limited, but a silicone coating treatment is preferred. Of these, a treatment for forming a cured silicone resin coating film is preferred.

The cured silicone resin coating film can be formed by applying a coating liquid containing a curable silicone resin on at least one side of a film, drying and curing.

As the curable silicone resin, any reaction system such as a condensation reaction system, an addition reaction system, and an ultraviolet or electron beam curing system can be used. One or more of these can be used.

The curing reaction of various silicones can be shown as follows.

[0036]

Embedded image

As the silicone resin for the condensation reaction system, for example, a polydimethylsiloxane having a terminal —OH group and a polydimethylsiloxane (hydrogensilane) having a —H group at a terminal may be an organic tin catalyst (eg, an organic tin acylate catalyst). ) To form a three-dimensional crosslinked structure.

As the silicone resin of the addition reaction system, for example, polydimethylsiloxane having a vinyl group introduced into a terminal and hydrogen silane are reacted using a platinum catalyst.
One that forms a three-dimensional crosslinked structure can be mentioned.

As the ultraviolet curing silicone resin,
For example, the most basic type uses the same radical reaction as ordinary silicone rubber crosslinking, the one that introduces an acrylic group and cures it, and the one that decomposes an onium salt with ultraviolet light to generate a strong acid, and this converts the epoxy group into an epoxy group. Examples thereof include those that are cleaved and crosslinked, and those that are crosslinked by the addition reaction of thiol to vinylsiloxane. Electron beams have higher energy than ultraviolet rays, and a radical crosslinking reaction occurs without using an initiator as in the case of ultraviolet curing.

The curable silicone resin has a degree of polymerization of about 50 to 200,000, preferably 1,000.
１００100,000 is preferred. Specific examples of these are KS-718, manufactured by Shin-Etsu Silicone Co., Ltd.
774, -775, -778, -779H, -830,
-835, -837, -838, -839, -841,
-843, -847, -847H, X-62-241
8, -2422, -2125, -2492, -249
4, -470, -2366, -630, X-92-14
0, -128, KS-723A / B, -705F, -7
08A, -883, -709, -719; TPR-6701, -6702, -670 manufactured by Toshiba Silicone Co., Ltd.
3, -3704, -6705, -6722, -672
1, -6700, XSR-7029, YSR-302
2, YR-3286; DK- manufactured by Dow Corning Co., Ltd.
Q3-202, -203, -204, -210, -24
0, -3003, -205, -3057, SFXF-2
560; SD-7226,7 manufactured by Toray Silicone Co., Ltd.
320, 7229, BY24-900, 171, 31
2,374, SRX-375, SYL-OFF23, S
RX-244, SEX-290; and SILCOLASE 425 manufactured by ICI Japan Ltd. Further, silicone resins described in JP-A-47-34447 and JP-B-52-40918 can also be used.

When the cured silicone resin film is formed on the film surface, a conventionally known method such as a bar coating method, a doctor blade method, a reverse roll coating method or a gravure roll coating method is used as a coating method. it can.

Drying and curing (thermal curing, ultraviolet curing, etc.) of the coating film can be performed individually or simultaneously. When performing simultaneously, it is preferable to perform at 100 degreeC or more. Desirable drying and heat curing conditions are 100 ° C. or higher and about 30 seconds. If the drying temperature is 100 ° C. or less, and the curing time is 30 seconds or less, the curing of the coating film is incomplete,
Uneasiness remains in durability such as falling off of the coating film.

The thickness of the cured silicone resin coating is not particularly limited, but is preferably in the range of 0.05 to 0.5 μm. If the thickness is too small, the release performance is reduced, and satisfactory performance cannot be obtained. On the other hand, if the thickness is too large, it takes a long time for curing, which causes inconvenience in production.

In the present invention, the above-mentioned release film is provided on a surface of the adhesive layer of a polarizing plate, a retardation polarizing plate or a retardation plate having an adhesive layer on one surface to form a laminate. At this time, the adhesive layer is laminated so that the cured silicone resin coated surface of the release film is in contact with the release layer.

The laminate of the present invention comprises a biaxially oriented aromatic polyester film in a release film, a direction of an orientation main axis measured by a microwave transmission type molecular orientation meter, a polarizing plate,
It is necessary that the directions of the orientation axes of the phase difference polarizing plate or the phase difference plate be substantially the same or positioned so as to be 90 °. Here "substantially the same"
This means that the two directions may be completely coincident or slightly deviated so as not to substantially interfere with visual inspection. Usually, a deviation of 5 ° or less, preferably 3 ° or less, is acceptable.

In general, the orientation of the principal axis of the biaxially oriented aromatic polyester film measured by a microwave transmission type molecular orientation meter (hereinafter, this may be simply referred to as “orientation principal axis”) is the longitudinal direction of the film. (Longitudinal direction) or lateral direction (width direction), so that, for example, the longitudinal direction of the film and the longitudinal direction (length direction; orientation axis direction) of the polarizing plate, retardation polarizing plate or retardation plate. Are satisfied, the above-mentioned lamination conditions can be satisfied.

In the laminate according to the present invention, the alignment principal axis of the release film and the alignment axis of the polarizing plate, the phase difference polarizing plate or the phase difference plate are coincident or deviated by 90 degrees. No interference color is generated, and foreign substances and defects can be easily detected. In addition, when the orientation main axis of the film and the orientation axis are coincident, the inspection is performed in a bright field, and when the orientation is shifted by 90 degrees, the inspection is performed in a dark field and only by reflected light. Inspection is easy. For example, inspection can be easily performed even with a size of 900 mm in length and 600 mm in width, and almost no foreign matter or defect is overlooked.

As the above-mentioned polarizing plate, retardation polarizing plate, retardation plate and adhesive layer, those conventionally known or used per se can be used. Among these, the polarizing plate, the phase difference polarizing plate, and the phase difference plate are preferably a large-screen TFT (active matrix) type or STN (super twisted nematic) type.

FIG. 1 is a schematic diagram showing the structure of the laminate of the present invention and the state of a visual inspection. In FIG. 1, 1 is the configuration of the laminated body, 2 is a protective film, for example, a thickness of 50 to 70 μm.
m, a polyethylene film, 3 is a polarizing plate (or retardation polarizing plate or retardation plate), usually having a thickness of 120 to 200 μm, 4 is an adhesive layer, usually having a thickness of 20 to 50 μm, 5 is a silicone release layer, and 6 is a silicone release layer. An axially oriented aromatic polyester film, 7 is a foreign substance or a defect, for example, having a size of 50 to 200 μm, and is present in the protective film 2. 8 is a polarizing plate for cross Nicol inspection, 9 is a light source such as a fluorescent lamp 20W. The lamp 10 is an opalescent diffusion plate. The laminate 1 is composed of a structure from a protective film to a biaxially oriented aromatic polyester film 6, and the release film is composed of a silicone release layer 5 and a biaxially oriented aromatic polyester film 6.

The foreign substances and defects inspected by using the laminate of the present invention are not limited to those existing in the protective film 2 as shown in FIG. It may be present in the plate, the adhesive layer, the silicone release layer or the biaxially oriented aromatic polyester film, and may be present between them. In any case, foreign matter and defects contained in the laminate can be easily found by visual inspection.

[0051]

EXAMPLES The present invention will be further described below with reference to examples. The physical properties in the examples were measured by the following methods.

(1) MOR value, inclination of oriented crystal main axis (orientation angle) Using a microwave molecular orientation meter manufactured by Kanzaki Paper Co., Ltd., MOR value, inclination of oriented crystal main axis (orientation) Angle).

(2) Visual Inspection Status (Effect of Optical Interference under Crossed Nicols) A visual inspection is performed using the configuration shown in FIG. 1, and the occurrence of optical interference is evaluated based on the following criteria. Good: Visual inspection No light interference occurred Slightly poor: Visual inspection Light interference occurred but inspection is possible Poor: Visual inspection Light interference occurred and inspection impossible

Examples 1-3 and Comparative Examples 1-4 Melted polyethylene terephthalate was extruded into a film, contacted with a rotating cooling drum at 20 ° C. and rapidly cooled to obtain an unstretched film. The film was successively biaxially stretched at the stretching ratio shown in Table 1 and heat-set under the conditions shown in Table 1 to obtain a transparent biaxially oriented polyethylene terephthalate film having a thickness of 38 µm.

Next, a silicone resin coating solution having the following composition was applied to one surface of the biaxially oriented polyethylene terephthalate film at a coating amount (wet) of 8 g / m ² ,
Drying and curing treatment under the conditions of × 30 seconds and coating film thickness of 0.24
A μm release film was obtained.

<Composition of coating liquid> Curable silicone resin (KS847H) 100 parts by weight Curing agent (CAT PL-50T; manufactured by Shin-Etsu Silicone Co., Ltd.) 2 parts by weight Diluent solvent: methyl ethyl ketone / xylene / methyl isobutyl ketone 898 parts by weight A polyester adhesive tape (Knit-31B) was adhered to the release surface of the release film, reciprocated with a 5 kg pressure roller, and the 180 ° tape peeling force after standing for 20 hours was measured. All were 9 g ± 2 g / 25 mm. And had sufficient release properties as a release film for a polarizing plate (release liner).

Using this release film, a laminate was formed with the structure shown in FIG. 1 and each characteristic was evaluated. Table 1 shows the results.

In Tables 1 and 2, symbols B, C, and F represent the total width (2190 mm) of the film-forming film divided into three equal parts (730 m).
m: The film portion on the left side when viewed from the winding position of the film forming film C: The central film portion when viewed from the winding position of the film forming film F: The film portion on the right side when viewed from the winding position of the film forming film. The physical property values are those of silicone coating.

The film used in Comparative Example 1 and the film used in Example 3 are obtained by dividing the film formed into three equal parts in the width direction. That is, the film (B) of Comparative Example 1 is the film portion on the left side when viewed from the winding position of the film forming film, and the films (C and F) of Example 3 are the film portion at the center when viewed from the same winding position. And the right film part. The difference between the MOR value and the difference between the maximum value and the minimum value of the MOR value in spite of the film cut in the length direction from the same film formed as described above is due to the bowing phenomenon at the time of film formation. It is presumed that the orientation main axis changes depending on the position.

[0060]

[Table 1]

Example 4 Instead of polyethylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate was used, and the temperature of the rotary cooling drum was set to 50 ° C.
A biaxially oriented polyethylene-2,6-natalenedicarboxylate film was obtained in the same manner as in Example 1 except that the film was heat-fixed under the conditions shown in Table 2. Next, a silicone resin coating solution was applied to one surface of the biaxially oriented polyethylene-2,6-natalenedicarboxylate film in the same manner as in Example 1, dried and cured to release a 0.24 μm thick coating. I got a film. Using this release film, a laminate was formed with the configuration shown in FIG. 1 and each characteristic was evaluated. Table 2 shows the results.

[0062]

[Table 2]

[0063]

According to the present invention, when laminated with a polarizing plate, a retardation polarizing plate or a retardation plate, light interference color in crossed Nicols does not substantially occur, visual inspection of foreign substances is facilitated, and a large screen is realized. LC
Also in the case of D, it is possible to provide a release film capable of preventing the occurrence of defective products by increasing the accuracy of foreign substance inspection, and providing a laminate having the improved polarization characteristics by laminating the release film.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a configuration of a polarizing plate foreign matter visual inspection;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 polarizing plate laminate, retardation polarizer laminate or retardation plate laminate 2 protective film 3 polarizing plate (stretching axis: lateral direction), retardation polarizer or retardation plate 4 adhesive layer 5 silicone release layer 6 2 Axial orientation aromatic polyester film 7 Foreign matter or defect 8 Polarizing plate for inspection of crossed Nicols 9 Light source 10 Opaque light diffusion plate Arrows (←) indicate the longitudinal direction (longitudinal direction) of the film.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI // B29C 71/02 B29C 71/02 G01N 21/84 G01N 21/84 EB29K 67:00 B29K 67:00 B29L 7:00 B29L 7:00 (56) References JP-A-1-127329 (JP, A) JP-A-60-192628 (JP, A) JP-A-1-165423 (JP, A) JP-A-3-161319 (JP, A) A) JP-A-5-157914 (JP, A) JP-A-4-277719 (JP, A) JP-A-5-107149 (JP, A) JP-A-6-297562 (JP, A) JP-A-6 JP-A-297561 (JP, A) JP-A-3-114735 (JP, A) JP-A-6-155567 (JP, A) JP-A-6-91811 (JP, A) JP-A-6-3664 (JP, A) ) Japanese Utility Model 58503 (JP, U) Japanese Utility Model 5-4103 (JP, U) (58) Fields surveyed (In t.Cl. ⁷ , DB name) G02B 5/30 B29C 55/14 B32B 7/02 B32B 27/00 B32B 27/36

Claims (5)

(57) [Claims] 1. A release film having an adhesive layer provided on one surface of a polarizing plate, a retardation polarizing plate or a retardation plate, and a transparent biaxially oriented aromatic polyester film as a base film on the surface of the adhesive layer. In the provided laminate, the biaxially oriented aromatic polyester film has a MOR value measured by a microwave transmission type molecular orientation meter in a range of 1.3 to 1.8,
And the difference between the minimum value and the maximum value of the MOR value is 0.2 or less, and the retardation value defined by the following equation (1)
(R) has at least 1200 (nm), ## EQU1 ## R = △ n · d ...... ( 1) ( where, △ n is the film of the visible light (wavelength λ = 589n
m) and the refractive index in the film width direction (nx) and its perpendicular direction
Is the difference (nx-ny) from the refractive index (ny) of the
This is the thickness (nm) of the film. ) Then, the laminate and the direction of the measured orientation main axis of a microwave transparent type molecular orientation meter of the biaxially oriented aromatic polyester film in (1) the releasing film, (2) a polarizing plate, a retardation polarizer Alternatively, a laminate having improved polarization characteristics, wherein the orientation directions of the orientation axes of the retardation plates are substantially the same or substantially 90 °. 2. The laminate according to claim 1, wherein the release film is a transparent biaxially oriented aromatic polyester film having at least one surface thereof subjected to release treatment by a silicone coating. 3. The laminate according to claim 1, wherein said aromatic polyester film is a polyethylene terephthalate film. 4. A release film in which at least one surface of a transparent biaxially oriented aromatic polyester film is subjected to a release property treatment by a silicone coating, wherein the biaxially oriented aromatic polyester film has a microwave transmission property. range of MOR values measured in a type molecular orientation meter is 1.3 to 1.8, and the difference between the minimum and maximum MOR value Ri <br/> Oh below 0.2, by the following formula (1) Defined retardation value
(R) has at least 1200 (nm), [Equation 2] R = △ n · d ...... ( 1) ( where, △ n is the film of the visible light (wavelength λ = 589n
m) and the refractive index in the film width direction (nx) and its perpendicular direction
Is the difference (nx-ny) from the refractive index (ny) of the
This is the thickness (nm) of the film. ) Polarizer, retardation polarizer or release film for inspection of retarder. 5. The release film according to claim 4 , wherein said aromatic polyester film is a polyethylene terephthalate film.