JP3403859B2 - Release film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a release film,
For more details, please refer to the polarizing plate, retardation polarizing plate or foreign matter of the retardation plate
If the release film of the present invention is used by lamination during inspection,
Release films that can easily inspect objects
I do. [0002] 2. Description of the Related Art In recent years, liquid crystal displays (LCDs) have been
Technologies for higher performance, higher image quality, higher color, and larger screen
Mi, and CRT (Cathode Ray Tube)
Lighter and lower energy consumption than display
Therefore, for example, a notebook personal computer
Widely used in displays such as word processors or word processors.
It has been adopted and spread rapidly, and its growth is remarkable. However, further growth of LCDs is not
Points that need to be reduced and cost rationalization is important
It has become. Large screens with particularly high reject rates
TFT (Thin Film Transistor)
  Active Matrix method and STN (Super Tsui)
(Stonematic) LCDs to improve the yield
There is an urgent need to rationalize costs. In an LCD, a polarizing plate, a retardation polarizing plate,
Or the phase difference plate can be used to make the transmitted light of LCD
It is necessary and important part to change hue,
Maintaining stable quality is an important issue for these too.
Process inspection, quality inspection, and shipping inspection standards are becoming increasingly strict.
It is the current situation. A polarizing plate, a retardation polarizing plate or a retardation plate
An adhesive layer is provided on one surface of the optical base material, and is separated on the adhesive layer.
Rolls the laminated body further laminated with the mold film
Transported or stored. And when manufacturing LCD
Then, take out each laminate from the roll and
Punched out, cut and used for LCD production. [0006] These laminates provided for the manufacture of LCDs
Inspection of foreign matter contamination and adhesion as one of the important items in inspection
This includes the polarizer polarizer manufacturing process as well as
Laminating process with release film, punching
Differences in all processes up to the cutting process and the
Material management is important. [0007] However, the inspection of foreign substances in the above-mentioned laminated body is a problem.
Ross Nicol method (Two polarizing plates are arranged with their stretching axes perpendicular to each other)
The sample film between the polarizers,
Method of inspecting foreign substances by visual inspection).
Especially for large screens.
Anisotropy of biaxially oriented polyester film
May interfere with accurate visual inspection.
As a result, oversight of foreign material contamination occurs with considerable frequency
are doing. [0008] The base film of the release film is
Axial oriented polyester film is usually used, especially for mechanical
Characteristics (thermal) and thermal characteristics (vertical (longitudinal)) and horizontal (width)
Direction) balanced biaxially oriented polyethylene teref
Tarate film is used. And this two axis
The direction of the main axis of crystal orientation of the oriented polyester film is
It does not match in both vertical and horizontal directions, both directions
Is almost in the middle of Further, the direction of the main axis of the crystal orientation is a film.
Significantly changes depending on the position in the horizontal direction (width direction).
You. This change is due to the bowing phenomenon during film formation.
It gets larger as it gets closer to both ends than the center. On the other hand, a polarizing plate, a phase difference polarizing plate or a phase difference
The plate is made using a uniaxially oriented polarizing film.
The direction of the opposite axis is usually the vertical direction. Therefore, a long polarizing plate, a phase difference polarizing plate,
Shows the phase difference plate and the release film taken out of the roll.
When laminated, polarizing plate, retardation polarizing plate or retardation
The orientation of the orientation axis of the plate and the biaxial orientation of the release film
The orientation of the crystal orientation main axis of the polyester film is shifted,
Crystal orientation of the biaxially oriented polyester film
The direction gradually changes from the center of the film to the end,
In particular, the deviation increases as the distance to both ends increases. Gained for this
Laminated film (polarizing plate, retardation polarizing plate or
Visual foreign matter inspection of the laminated body of the retardation film and the release film)
Light interference color occurs when performing the cross Nicol method, and
The closer to both ends of the film, the stronger this is.
Object inspection becomes difficult. When the width of the laminate is narrow, in other words, L
If the CD is small, the light interference color may be slightly different
Object inspection accuracy can be secured to some extent, but if the width is wide,
In other words, if the LCD has a large screen,
It is extremely difficult to check all foreign substances. Also, a biaxially oriented film constituting a release film is provided.
Foreign matter that can be detected optically in the ester film
When the polarizing plate is present, the polarizing plate and the
Can be distinguished from a retardation polarizer or a foreign substance existing on a retardation plate.
In this case, accurate foreign substance inspection becomes difficult. [0013] SUMMARY OF THE INVENTION It is an object of the present invention to
When laminated with a plate, a retardation polarizing plate or a retardation plate,
Light interference color does not substantially occur, and visual observation by cross Nicol method
Easy inspection of foreign matter, especially for large screen LCD
Improve detection accuracy by minimizing oversight of foreign objects as much as possible
To prevent the occurrence of products, and a polarizing plate, a retardation polarizing plate or
Or good quality by increasing the detection accuracy of foreign substances present in the phase difference plate
Release film used to improve the yield of
To provide. [0014] [Means for Solving the Problems] According to the research of the present inventors,
If the object of the present invention is a transparent biaxially oriented polyester
Silicone resin as the main component on at least one side of the film
Release film provided with a release coating film
The axially oriented polyester film is25 in polyester
Polyester blended with lubricant to remove aggregated particles of μm or more
Extrusion of a steal composition with a sintered metal filter
Unstretched film obtained by extruding into a film from a
Lum is obtained by biaxial stretching, andDefined by the following equation (1)
Retardation value (R) is 1200 (nm) or less
Above, MO measured by microwave transmission type molecular orientation meter
R value is in the range of 1.3 to 1.8, and the minimum of the MOR value is
The difference between the value and the maximum value is 0.2 or less, and the length of one side is 2
10 mm and the width of the side orthogonal to it is 148 mm
(Area 310.8cm^Two25 μm per film)
Above foreign matter does not exist, foreign matter of 5 μm or more and less than 25 μm
Polarizer, retardation polarizer or retardation having 10 or less
Achieved by a release film for board inspection. [0015] R = △ n · d Equation (1) (However, in equation (1), Δn is the visible light (wavelength λ) of the film.
= 589 nm) and the refractive index (nx) in the film width direction.
The difference (nx−ny) from the refractive index (ny) in the perpendicular direction
And d is the thickness (nm) of the film. ) Hereinafter, the present invention will be described in detail. In the present invention, the base film of the release film is used.
Although the biaxially oriented polyester film is used for the film,
The polyester constituting the base film is dicarbohydrate.
A linear polyester consisting of an acid component and a glycol component
is there. As the dicarboxylic acid component, for example,
Phthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid
Aromatic substances such as tallic acid and 4,4'-diphenyldicarboxylic acid
Dicarboxylic acids, especially terephthalic acid
Alternatively, 2,6-naphthalenedicarboxylic acid is preferred. As the glycol component, for example,
Tylene glycol, diethylene glycol, propylene
Glycol, 1,3-propanediol, 1,4-buta
Diol, neopentyl glycol, 1,5-pentane
Diol, 1,6-hexanediol, 1,4-sic
Rohexane dimethanol and the like, in particular,
Ethylene glycol is preferred. Constituting the base film in the present invention
As the polyester, among the above polyesters, poly
Ethylene terephthalate or polyethylene-2,6-
Naphthalate is the base film's mechanical and thermal properties
Etc. are preferred because they are excellent. The above-mentioned polyester is made of the above-mentioned dicarboxylic acid
Polyester copolymerized with glycerol or glycol component
May be a trifunctional or higher polycarboxylic acid component or
Is a polyol component whose polyester is substantially linear
Polystyrene copolymerized in a small amount within the range (for example, 5 mol% or less)
Tell may be. In the present invention, the second film used for the base film is used.
The axially oriented polyester film is25 in polyester
Polyester blended with lubricant to remove aggregated particles of μm or more
Extrusion of a steal composition with a sintered metal filter
Unstretched film obtained by extruding into a film from a
Lum is obtained by biaxial stretching, andDefined by equation (1)
Retardation value (R) is 1200 (nm) or less
Above, MO measured by microwave transmission type molecular orientation meter
R value is in the range of 1.3 to 1.8, and the minimum of the MOR value is
The difference between the value and the maximum value is 0.2 or less, and the length of one side is 2
10 mm and the width of the side orthogonal to it is 148 mm
(Area 310.8cm^Two(Nippon Kogyo)
A film that conforms to the industry standard A5 size
In the following, it is abbreviated as “per A5 plate”. ) 25
No foreign matter of more than 5 μm and less than 25 μm
No more than 10 foreign objects. The base film micro according to the present invention
MOR (Maximum Orient) measured with a wave transmission type molecular orientation meter
ed Ratio) value is in the range of 1.3 to 1.8, preferably
Is in the range of 1.35 to 1.75. This MOR value is
The values measured at three points in the width direction of the
It is necessary to satisfy the enclosure. The location of the MOR value measurement is
The center point in the width direction of the lum and its center
1/5 point on the side of the end connecting the film and the film ends
A total of three places, that is, one in the straight line in the width direction of the film
At 10%, 50% and 90% distance from one end
Place. The MOR value is measured in the film width direction.
There are three places as described above.
Direction), for example, the length of the film width
1.0 to 5 times, preferably 2 to 3 times at intervals
You can choose a place. Here, the MOR value is a transmission type molecular orientation meter.
Of the maximum and minimum transmitted microwave intensities measured at
(Maximum value / minimum value). This MOR value is
Balanced film with a small difference in the stretching ratio in the transverse direction
The difference between the stretching ratio in the vertical and horizontal directions
Larger, the larger the stretching strength in one direction, the larger
You. This MOR value tends to change in the film width direction.
At the measurement points (three places) in the film width direction.
The difference (the difference between the maximum value and the minimum value) is 0.2 or less.
And it is particularly preferable that it is 0.15 or less.
Good. Further, the base used in the release film of the present invention is
Film is a retardation defined by the following equation (1).
The value (R) is 1200 nm or more. [0026] R = △ n · d Equation (1) (However, in equation (1), Δn is the visible light (wavelength λ) of the film.
= 589 nm) and the refractive index (nx) in the film width direction.
The difference (nx−ny) from the refractive index (ny) in the perpendicular direction
And d is the thickness (nm) of the film. ) Biaxially oriented polyester films are birefringent,
When incident, the incident light is divided into two beams whose vibration planes are orthogonal to each other.
It propagates as linearly polarized light. These two linearly polarized lights (ordinary ray and
The difference between the extraordinary rays is called the phase difference (retardation: R).
This phase difference causes color interference in the polarizing plate inspection process.
Influence as color. Michel-Le in orthogonal Nicols
According to the interference color chart (polarized light microscope) of the renovation, low Rita
In the dark area (black),
Interference color is yellow → red → purple → blue in proportion to the gradation
→ The color changes from green to yellow again, and the same cycle is repeated.
Return. However, according to the research of the present invention, the retardation
From about 1200 nm, the density of the interference color sharply increases.
Drastically drop, and therefore the retardation R
If it is large, the interference color is extremely small, and it is difficult to perform a visual inspection.
It turned out to be no harm. Therefore, optical rita
The optimal range of the retardation value (R) is 1200 (nm) or less.
The thickness of the film normally used is 25 to 50 μm.
1300 in the case of biaxially oriented polyester film of
(Nm) or more is most preferable for the release film.
I understood. In support of this requirement, generally birefringence
And the amount of transmitted light (I) under crossed Nicols of a transparent plate having
Radiation (I₀) Ratio (I / I₀) Is represented by the following formula (2).
It is. [0029] (Equation 4) (I / I₀) = Sin^Two(2θ) · Sin^Two(Π · △ nd · λ) Equation (2) The crossed Nicols of a transparent plate having birefringence make it transparent.
The ratio between the amount of excess light and the amount of incident light is the angle of existence of the birefringent body between Nicols.
The smaller the degree (θ: equivalent to the orientation angle in the present invention), the smaller the extinction position
Becomes Conditions for the extinction position include the following (a) and
(B). (A) When θ is small (B) △ n · d / λ = R / λ is a natural number 1, 2, 3, ...
(When R is an integral multiple of the light source wavelength: λ) The closer the orientation angle θ is to zero, the closer the ratio of the formula (2) is to zero.
The extinction position, and the foreign matter emerges white,
The efficiency of visual inspection is most improved. At the same time retardation
R is an average of 5 in the visible light wavelength range of 420 nm to 760 nm.
A multiple of about 90 nm is preferable, and R = 1200 (nm)
In the case of, when the orientation angle θ is small,
For further retardation R, the crossed Nicols
In the interference color chart, the light interference concentration will decrease sharply.
Therefore, it is necessary that R is 1200 nm or more.
This is a necessary condition. The upper limit of the retardation R is the film thickness
Depending on the thickness, but in the range of 25 μm to 50 μm
Does not need to set an upper limit. Also, the base used in the release film of the present invention is
The film is 25 μm or less per A5 plate of the base film.
Above the foreign matter does not exist, foreign matter of 5μm or more and less than 25μm
10 or less. 2 per base film A5
If there is a foreign substance of 5 μm or more, or 5 μm or more and 25
When the number of foreign substances less than μm is 11 or more, the polarizing plate,
A retardation polarizing plate or a laminate of a retardation plate and a release film
If there is no foreign matter at the time of foreign matter inspection of
Non-defective polarizing plate, retardation polarizing plate or retardation plate
Therefore, the yield is significantly reduced.
In addition, 5 µm or more and 25 µm or less per base film A5
The number of full foreign substances is preferably 3 or less, particularly preferably 1
Not more than The smaller the number of these foreign substances, the more
It is preferable because the yield of the polarizing plate or the retarder is improved.
No. A polarizing plate, a phase difference polarizing plate or a phase difference plate
Foreign matter less than 5 μm in the
Foreign particles less than 25 μm are present in 10 or less per A5 size
It does not cause any problem even if it is used for LCD production
Therefore, there is a foreign substance of less than 5 μm in the base film.
5μm or less per base film A5
If the number of foreign substances less than 25 μm is 10 or less,
May be. Here, the foreign matter in the present invention is a cloth
Optically detectable by visual inspection by Nicol method
Foreign matter, for example, producing polyester film
Inorganic and organic lubricants added when agglomerated and coarsened
Or mixed during the production of polyester film
Foreign matter and the like can be mentioned. The size of the foreign matter in the present invention is as follows:
Measure as described. That is, visual observation by the cross Nicol method
Biaxially oriented polyester optically detected during inspection
Foreign matter in the film is transmitted through a separate optical microscope.
Observed as an optically abnormal area
The maximum diameter of the minute is defined as the size of the foreign matter. In addition, for example, the lubricant
The film was stretched around the gathered and coarse foreign substances.
When this occurs, a void is created, which is optically different.
If it is observed as a normal range, include it in the size of the foreign matter
Was. The number of foreign substances was measured by using a sample film from Nippon Kogyo.
Standard paper size A5 size (standard length 210m)
mx 148 mm wide: 310.8 cm area^TwoTo the size of
Cut and count the number of foreign objects in the entire area of this film.
And it was done by. Biaxially oriented poly used as base film
Ester film has the following characteristics in addition to the above characteristics.
Is preferred. (1) Transparency suitable for visual appearance inspection. Adhesive surface evenly
Flatness to the surface. Rays of biaxially oriented polyester film
The transmittance is preferably 80% or more, particularly preferably 85% or more.
New When the light transmittance is within this range, the polarizing plate, the phase difference
The release film of the present invention is laminated on a polarizing plate or a retardation plate.
When performing foreign substance inspection by the cross Nicol method,
Identification can be easily performed. (2) Adhesive coating and polarizing film performed under high tension heating
Heat resistance, high strength elongation and high elasticity to withstand lamination with
Sex rate. For example, the following elongation at break, elastic modulus and heat shrinkage
It is preferred to have. [0038]       Film elongation at break: 100-250% in the length direction                         50-150% in width direction       Film elastic modulus: Length direction 300 to 700 kg / mm^Two                         400-800Kg / mm in width direction^Two       Film heat shrinkage: 1.0% or less in the longitudinal direction (110 ° C x 30 minutes)                         0.5% or less in the width direction (110 ° C x 30 minutes) (3) Deviation from the adhesive interface due to heat shrinkage of the release film
Tunneling caused by the occurrence of
Dimensional stability with no elephant or curl. (4) 25 to 50 μm thickness. The biaxially oriented polyester fiber used in the present invention
Lum can be obtained, for example, by the following method. That is,
Melt the polyester and cast it on a cooling drum
Unstretched film, and then the unstretched film is
At a secondary transition point (Tg) of the ester of −10 ° C. or higher,
For example, 2.5 times or more and 6 times in the vertical and horizontal directions, respectively.
It can be obtained by biaxial stretching within the impossible range
You. At this time, the stretching ratio in the vertical direction is equal to the stretching ratio in the horizontal direction.
0.5 or more, 0.7 or more, or
The elongation ratio is 0.5 or more than the elongation ratio in the longitudinal direction, and furthermore
It is preferably larger than 0.7. In the biaxial stretching, a simultaneous biaxial stretching method is used.
Stretching may be used, but the latter is preferred. And biaxial stretching
Reduces bowing across film width during subsequent heat setting
It is preferable to add a zoning treatment means such as soot. Twin shaft
The film after stretching and heat setting is 30 minutes at 150 ° C (no load
The heat shrinkage when holding the load is 4 in both the vertical and horizontal directions.
% Is preferable. The release film of the present invention comprises the above biaxially oriented film.
Silicone resin on at least one side of the polyester film
Provided a release coating (silicone release layer) as the main component
Things. The method of providing this silicone release layer is particularly
Although not limited, a coating liquid containing silicone resin is applied and added.
The method of coating by heating is preferable, and particularly,
It is preferable to apply a cone resin coating. This cure
The silicone resin coating is a coating containing a curable silicone resin.
Apply the liquid to at least one side of the film, dry and cure
Can be formed. As the curable silicone resin, for example,
Synthetic reaction type, addition reaction type, UV or
Use any reaction system such as a wire-curing system.
Can be. One or more of these can be used. The curing reaction of various silicones is as follows.
Can be shown. [0044] Embedded image As the silicone resin of the above condensation reaction system
Is, for example, a polydimethylsiloxane having an --OH group
Sun and polydimethylsiloxane with terminal -H group
(Hydrogensilane) with an organotin catalyst (eg, organotin)
Condensation reaction using an acylate catalyst)
There are things that make structures. As an addition reaction type silicone resin,
Is, for example, polydimethylsilyl with a vinyl group introduced at the end.
Reaction of xane and hydrogen silane using platinum catalyst
To form a three-dimensional cross-linked structure
You. Further, an ultraviolet curing reaction type silicone resin
For example, the most basic type is a regular
One that uses the same radical reaction as corn rubber crosslinking,
Photo-curing by introducing a krill group.
Decompose the salt to generate a strong acid, which opens the epoxy group.
Cleavable and cross-linked, thiol to vinyl siloxane
And the like which are crosslinked by the addition reaction of
In addition, the silicone resin of the electron beam curing reaction system
Use the same silicone resin as the curing reaction system
it can. Since electron beams have more energy than ultraviolet light,
An electron beam is emitted without using an initiator as in the case of UV curing.
Irradiation promotes the crosslinking reaction by radicals
Can be As the curable silicone resin, its polymerization
Degree of about 50 to 200,000, preferably 1,000
About 100,000 are preferable.
For example, 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; Toshiba Silicon Corporation
TPR-6701, -6702, -670
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; ICI
SILCOLASE 425 manufactured by Japan Corporation
Can be Also, Japanese Patent Application Laid-Open No. 47-34447
And silicon described in JP-B-52-40918.
Resin can also be used. The cured silicone resin coating was applied to a film table.
When forming on the surface, apply the coating liquid to the film surface
Bar coating method, doctor blade method, river
Roll coat method or gravure roll coat method
A conventionally known method can be used. still,
The application of the silicone resin coating prevents foreign matter from being mixed.
Do this in a facility where measures have been taken. Drying and curing of coating film (thermal curing, ultraviolet curing)
Can be performed individually or simultaneously.
You. When performing simultaneously, it is preferable to perform at 100 ° C or more.
New Drying and heat curing conditions are above 100 ° C
About 30 seconds is desirable. The drying temperature is 100 ° C. or less, and
When 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 particularly limited.
Not specified, but preferably in the range of 0.05-0.5μm
No. If it is too thin, the release performance will decrease and it should be satisfactory
Performance cannot be obtained. If it is too thick, it will cure
It takes time and causes inconvenience in production. The release film of the present invention comprises a polarizing plate, a retardation
On the surface of the adhesive layer provided on one side of the polarizing plate or retarder
The adhesive layer and the release film
Laminated so that the silicone resin coating surface of
You. The laminate obtained by laminating the release films is as follows:
Of biaxially oriented polyester film in release film
Crystal orientation principal axis measured by microwave transmission type molecular orientation meter
And the orientation of the polarizer, retarder or retarder
Match or make sure that the directions of the axes are substantially the same
Must be located at 90 °. here
"Substantially the same" means that the two directions exactly match.
Or slightly deviated to the extent that it does not actually interfere with visual inspection
Means that it may be. Usually 5 ° or less, preferably
A deviation of 3 ° or less is acceptable. In general, biaxially oriented polyester films
Crystal orientation principal axis measured by microwave transmission type molecular orientation meter
(Hereinafter, this may be simply referred to as “orientation main axis”)
The direction of the film can be either vertical (longitudinal) or horizontal
(Width direction).
The longitudinal direction of the polarizing plate, the retardation polarizing plate or the length of the retardation plate
Direction (length direction; orientation axis direction)
The above-mentioned lamination conditions can be satisfied. The above-mentioned laminate is composed of the main axis of orientation of the release film.
And the alignment axis of the polarizing plate, retardation polarizing plate or retardation plate
Eyes by crossed Nicols method
Light interference color is not generated in visual foreign matter inspection, and foreign matter or missing
Can detect a fall. In addition, the orientation main axis of the film and the polarizing plate,
The alignment axis of the phase difference polarizing plate or the phase difference plate matches
Inspection in the bright field and dark field
In the field, inspection is performed only with reflected light, but in any case
Foreign substance inspection is easy. For example, length 900mm, width 6
Inspection is easy even with a size of 00 mm, and foreign matter and defects are
There is almost no oversight. Polarizing plate, retardation polarizing plate, retardation plate and the same
For the adhesive layer to be laminated, a conventionally known adhesive layer
Can be used. Among these, polarizing plate, phase contrast polarization
The large screen TFT (activator)
Bumatric), STN (Super Twisted Nemate)
Dick) type is preferred. FIG. 1 shows a product using the release film of the present invention.
It is a schematic diagram which shows the structure of a layer body, and the state of a visual inspection.
In FIG. 1, reference numeral 1 denotes a configuration of a laminate, and 2 denotes an example of a protective film.
For example, a polyethylene film having a thickness of 50 to 70 μm,
Polarizer (or retardation polarizer or retarder) usually 1
20-200 μm thickness, 4 is an adhesive layer, usually 20-50
μm thickness, 5 is silicone release layer, 6 is biaxially oriented poly
Ester film, 7 is a polarizing plate for cross Nicol inspection, 8
Is a milky light diffusion plate, 9 is a light source, for example, two fluorescent lamps 20W.
is there. The laminate 1 is made of a biaxially oriented polyester film from a protective film.
From the structure up to film 6 and the release film
Cone release layer 5 and biaxially oriented polyester film 6
It is composed of [0058] The present invention will be further described below with reference to examples.
You. The physical properties in the examples were measured by the following methods. (1) MOR value, inclination of main axis of crystal orientation (distribution)
Diagonal) Transmission using a microwave molecular orientation meter manufactured by Kanzaki Paper Co., Ltd.
The pattern of the biaxially oriented polyester film
MOR value of the film sample, inclination of the main axis of crystal orientation (orientation
Angle). (2) Visual inspection status (under crossed Nicols)
Effect of optical interference) A visual inspection is performed using the configuration shown in FIG.
Evaluation was made according to the following criteria. Good: Visual inspection No light interference Slightly poor: visual inspection Optical interference occurs but inspection is possible Defective: visual inspection Inspection impossible with optical interference (3) Visual inspection status (defective product detection rate) With the configuration shown in FIG. 1, the laminate (protective film, polarizing plate, adhesive
Layer, release layer and biaxially oriented polyester film)
An inspection was performed, and defective products as a laminate were extracted. Then
Release film (release) from the laminate extracted as defective
Layer and biaxially oriented polyester film)
Of the obtained polarizing plate (protective film, polarizing plate and adhesive layer)
Perform a visual inspection to extract defective polarizers,
Calculate the defective detection rate when measuring with
Was. Good: Defective product detection rate is 90% or more Slightly defective: defective rate is 50% or more and less than 90% Defective: Defective product ratio is less than 50% or cannot be inspected (4) Measurement of the number of foreign substances Biaxially oriented polyester film sample
Size according to the standard base paper size A5
0 mm x 148 to 149 mm wide: about 310 cm in area^Two)
And cut the entire area of this film by the cross Nicol method.
Foreign material inspection by visual inspection was performed. Then detected
Foreign matter in the sample film
Observed due to excessive light, observed as an optically abnormal range
The maximum diameter of the portion where the diameter is equal to the size of the foreign matter. In addition, around the foreign matter
Existing cavities (voids) are viewed as optically abnormal areas.
If it was detected, it was included in the size of the foreign matter. In addition, the size of foreign matter
Is 25 μm or more, and 5 μm or more and less than 25 μm
And the number of foreign substances per A5 plate was measured.
Was. (5) Light transmittance Murakami Color Research Laboratory Co., Ltd. HR-100 type
Light with a wavelength of nm is incident on the film,
The ratio of the total transmitted light amount to the emitted light amount was defined as the light transmittance. [Example 1] Polyethylene terephthalate
25 parts by air classifier as lubricant for 100 parts by weight
Alumina particles from which aggregated particles of μm or more have been removed 0.00
An extruder (extruder) containing 5 parts by weight of the polyester composition
A sintered metal filter was installed between the machine tip and the die
Polyethylene terephthalate supplied and melted
Extruded into a film and contacted with a rotating cooling drum at 20 ° C.
It was quenched and quenched to obtain an unstretched film. Then, the unstretched
The film was sequentially biaxially stretched at the stretching ratio shown in Table 1, and further
Heat-fixed under the conditions shown in Table 1, thickness 38 μm, light transmittance
88% biaxially oriented polyethylene terephthalate film
I got This biaxially oriented polyethylene terephthalate film
Lum film thickness, film width, MOR value, MOR value
The difference between the maximum and minimum values of the retardation value (R) and
Table 1 shows the results of measuring the number of foreign substances. Next, the biaxially oriented polyethylene terephthalate
One side of the rate film is coated with a silicone resin of the following composition.
8 g / m of liquid application amount (wet)^TwoApply at 130 ℃
Drying and curing treatment under the condition of 30 seconds and coating thickness 0.24μ
m of release film was obtained. [0066]   <Composition of coating liquid> 100 parts by weight of curable silicone resin (KS847H) 2 parts by weight of curing agent (CAT PL-50T; Shin-Etsu Silicone) Diluent solvent: 898 parts by weight of methyl ethyl ketone / xylene / methyl isobutyl ketone Polyester adhesive tape on the release surface of the release film
(Knit-31B) and stick with 5kg pressure roller
Measure the 180 degree tape peeling force after reciprocating and leaving for 20 hours.
After all, it was within the range of 9g ± 2g / 25mm.
And used as a release film (release liner) for polarizing plates.
And had sufficient mold release characteristics. Peel off this release film
The measurement results of the separation force, the vertical thermal shrinkage and the horizontal thermal shrinkage are displayed.
It is shown in FIG. Using this release film, FIG.
A laminate was made with the following configuration, and each characteristic was evaluated. As a result
Are shown in Table 1. Examples 2-3 and Comparative Examples 1-4 Stretching
Except that the magnification and heat setting temperature were changed to the conditions shown in Table 1.
As in Example 1, the thickness is 38 μm, and the light transmittance is 85 to 85 μm.
90% biaxially oriented polyethylene terephthalate film
I got These biaxially oriented polyethylene terephthalates
Film thickness, film width, MOR value, MO of film
Difference between maximum and minimum values of R value, retardation value (R)
Table 1 shows the measurement results of the number of foreign substances. Next, these biaxially oriented polyethylene fibers
On one side of the phthalate film, in the same manner as in Example 1.
Applying a silicone resin coating to release with sufficient release characteristics
Mold film, and then using these release films
A laminate was made in the same manner as in Example 1, and each characteristic was evaluated.
Was. Table 1 shows the results. In Table 1, symbols B, C and F are film-forming films.
Of the whole width (2190mm) into three equal parts (730mm)
Cut B: Film part on the left side when viewed from the film winding position
Minute C: Film part at the center when viewed from the film forming film winding position
Minute F: Film part on the right side when viewed from the film winding position
Minute Is shown. Film used in Comparative Example 1 above and implementation
The film used in Example 3 was a film formed
Is divided into three equal parts in the width direction. That is, Comparative Example 1
Film (B) is viewed from the winding position of the film
The left side of the film portion, the film of Example 3 (C and
And F) are the film parts in the center when viewed from the same winding position.
Minute and right film part. The film is formed like this
Film that has been cut lengthwise from the same film
MOR value and maximum value of MOR value respectively
The difference between the minimum value and
Orientation axis changes with position due to
It is presumed that. Comparative Example 5 A filter made of sintered metal was mounted.
Biaxially stretched polyester is the same as in Example 1 except that
Make a telfilm and release it in the same manner as in Example 1.
Films and laminates were made and their properties were evaluated. this
Table 1 shows the results. Example 4 Polyethylene Terephthalate
Instead of polyethylene-2,6-Natalendicarboki
Using a sylate, the temperature of the rotary cooling drum was set to 50 ° C,
Same as Example 1 except that stretching and heat setting were performed under the conditions shown in Table 1.
Biaxially oriented polyethylene having a light transmittance of 90%
A 2,6-natalenedicarboxylate film was obtained.
This biaxially oriented polyethylene-2,6-natalendicarbo
Xylate film thickness, film width, MO
R value, difference between MOR maximum and minimum, retardation
Table 1 shows the measurement results (R) and the number of foreign particles. Next, the biaxially oriented polyethylene-2,
6-Natalen dicarboxylate film
A silicone resin coating solution was applied in the same manner as in Example 1, and dried and hardened.
To obtain a release film with a coating thickness of 0.24 μm
Was. Table 1 shows the characteristics of the release film. Furthermore, this
Using a release film, a laminate is formed in the same manner as in Example 1.
Each characteristic was evaluated. This result is good as shown in Table 1.
It was good. [0074] [Table 1][0075] The release film of the present invention can be used as a polarizing plate and a retardation film.
Foreign matter by the crossed Nicols method laminated on a polarizing plate or retardation plate
When used for inspection, light interference color at crossed Nicols is substantially
For large LCD screen
Also improves the accuracy of foreign substance inspection to prevent defective products
can do.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing the structure of a polarizing plate foreign matter visual inspection [Description of symbols] 1 polarizing plate laminate, retardation polarizing plate laminate or retardation plate laminate 2 protective film 3 polarization Plate (stretching axis: lateral direction), retardation polarizing plate or retardation plate 4 Adhesive layer 5 Silicone release layer 6 Biaxially oriented polyester film 7 Polarizing plate for cross Nicol inspection 8 Opalescent diffusion plate 9 Light source arrow (←) The vertical direction (longitudinal direction) of the film is shown.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI G02B 5/30 G02B 5/30 B29K 67:00 B29K 67:00 B29L 7:00 B29L 7:00 (58) Fields surveyed (Int. .Cl. ⁷ , DB name) B32B 1/00-35/00 B29C 55/00-55/30 B29C 47/00-47/96 G01N 21/84-21/958 G02B 5/30

Claims (1)

(57) Claims: 1. A release film comprising a transparent biaxially oriented polyester film provided on at least one surface with a release coating mainly composed of a silicone resin. The axially oriented polyester film has a thickness of 25 μm or more in the polyester.
Polyester composition with lubricant removed aggregated particles
From the extruder equipped with a sintered metal filter.
Unstretched film obtained by extruding and quenching into a
A film obtained by stretching and having a retardation value (R) defined by the following formula (1) of not less than 1200 (nm);
The MOR value measured by a microwave transmission type molecular orientation meter is 1.
3 to 1.8, the difference between the minimum value and the maximum value of the MOR value is 0.2 or less, and the width (area 31) of 210 mm on one side and 148 mm on the side orthogonal to it.
A release film for inspecting a polarizing plate, a retardation polarizing plate or a retardation plate, in which no foreign matter of 25 μm or more is present in the film per 0.8 cm ² ) and there are no more than 10 foreign matter of 5 μm to less than 25 μm. . R = △ n · d Equation (1) (where, in Equation (1), Δn is the visible light (wavelength λ) of the film.
= 589 nm), the difference (nx-ny) between the refractive index (nx) in the film width direction and the refractive index (ny) in the direction perpendicular to the film width, and d is the thickness (nm) of the film. )