JP2012139930A - Two sided release film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two sided release film which is especially suitably used in a photocurable resin layer manufacturing process, and is controlled excellent in light shielding and mold releasability.SOLUTION: A release film for manufacturing an optical member is a film which has release layers with different peel forces in both sides of a polyester film respectively is characterized in that the light transmittance in a wavelength region of 300-375 nm is 0.2% or less; a remaining Si-H rate of the release layer surface of larger peel force is 5% or less; the peel forces of the release layer concerned is 2.0-6.0 times of the peel force of the other release layer; and the residual bonding rates of both release layer are 80% or more.

Description

  TECHNICAL FIELD The present invention relates to a release film having ultraviolet absorptivity and releasability, and is used for manufacturing LCD components such as polarizing plates and retardation plates used in liquid crystal displays (hereinafter abbreviated as LCD), plasma displays. For the production of various display components such as panel (hereinafter abbreviated as PDP) component production, organic electroluminescence (hereinafter abbreviated as organic EL) component production, etc., for example, photocuring formed by ultraviolet irradiation The double-sided release film suitable for the manufacturing process which shape | molds a conductive resin layer is provided.

  Conventionally, release films based on polyester films have been used in various optical applications such as LCD polarizing plates, retardation plates, PDP components, organic EL components, and various display components. Is used.

  In recent years, with the advancement of IT (Information Technology) field, the required quality of optical members that constitute displays has been steadily improving with higher functionality in display members such as LCDs, PDPs, and organic ELs. Optical members are needed.

While the necessity of manufacturing an optical member with high accuracy is increasing, a photocurable resin may be used for the reason of being able to cope with a complicated surface shape with patterning when manufacturing an optical component (for example, Patent Document 1). A release film may be used in the manufacturing process for forming the photocurable resin layer. In the manufacturing process, for example, a photocurable resin is applied on a release film and dried, and then a desired pattern is formed by UV exposure from the release layer side, and the release film is peeled from the photocurable resin layer. It consists of manufacturing processes such as. In the manufacturing process, it is necessary to suppress the amount of ultraviolet light transmitted through the release film as much as possible during ultraviolet exposure.

  When the amount of ultraviolet light is large, the light-shielding property of the release film becomes insufficient, and when the ultraviolet ray is irradiated from the release surface side on which the photocurable resin is previously laminated, after the photocurable resin molding, after pattern formation, In some cases, the dimensional accuracy of the obtained optical member does not reach a desired level. For this reason, the release film tends to require a higher degree of light shielding than ever before.

As for the release layer constituting the release film, a photocurable resin is applied to the release layer surface.
After drying, when the production process is further performed by irradiating with ultraviolet rays from the surface of the release layer, the adhesion between the release layer and the photocurable resin layer is improved, so that it may be difficult to peel off when releasing the release film. .
Therefore, a release film in which the interaction between the release layer and the photocurable resin layer is as small as possible is required in the step of applying, drying, and irradiating the photocurable resin layer.

  On the other hand, in the configuration in which the release layer is provided only on the surface to which the photo-curing resin is applied, when the photo-curing resin is applied, and after drying, patterning by ultraviolet exposure is not performed in a series of steps, the mold release Although it is necessary to wind in the shape of a roll with the photocurable resin layer provided on the film, the photocurable resin layer is wound in contact with the non-release surface, so that the roll is used in the next step. At the time of unwinding, the photocurable resin peels off from the release surface (so-called floating) due to the adhesiveness due to the close contact with the non-release surface, so that it becomes impossible to cope with a complicated surface shape in patterning, etc. Will cause problems.

JP 2006-30621 A JP 2007-34026 A JP 2009-220462 A JP 2009-214331 A

  The present invention has been made in view of the above circumstances, and the problem to be solved is a double-sided mold release that is preferably used particularly in a photocurable resin layer manufacturing process, and in which the light shielding property and the mold release property are well controlled. To provide a film.

  As a result of intensive investigations in view of the above-mentioned actual situation, the present inventor has found that the above-mentioned problems can be easily solved by a release film having a specific configuration, and has completed the present invention.

  That is, the gist of the present invention is a film having release layers having different peeling forces on both sides of a polyester film, the light transmittance in the wavelength region of 300 to 375 nm is 0.2% or less, and the peeling force is large. The remaining Si—H ratio on the surface of the release layer is 5% or less, the release force of the release layer is 2.0 to 6.0 times the release force of the other release layer, The residual adhesion rate of the mold layer is 80% or more, and the present invention resides in a release film for producing an optical member.

  According to the release film of the present invention, the light transmittance in the wavelength region of 375 nm or less is small, the light shielding property is good, particularly for the molding of the photocurable resin layer. Is as small as possible and can provide a release film having good release properties, and its industrial value is high.

  The polyester film constituting the release film in the present invention may have a single-layer structure or a laminated structure. For example, the polyester film may have a four-layer or a three-layer structure as long as the gist of the present invention is not exceeded other than the two-layer or three-layer structure. It may be a multilayer having more than that, and is not particularly limited.

  The polyester used for the polyester film in the present invention may be a homopolyester or a copolyester. In the case of a homopolyester, those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol are preferred. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Representative polyester includes polyethylene terephthalate (PET) and the like. On the other hand, examples of the dicarboxylic acid component of the copolyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acid (eg, P-oxybenzoic acid). 1 type or 2 types or more are mentioned, As a glycol component, 1 type or 2 types or more, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1, 4- cyclohexane dimethanol, neopentyl glycol, is mentioned. In any case, the polyester referred to in the present invention refers to a polyester that is usually 60 mol% or more, preferably 80 mol% or more of polyethylene terephthalate or the like which is an ethylene terephthalate unit.

  In the present invention, it is preferable to blend particles in the polyester layer mainly for the purpose of imparting slipperiness. The type of particles to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness as long as it does not impair the gist of the present invention. Specific examples include silica, calcium carbonate, magnesium carbonate, Examples of the particles include barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, and titanium oxide. Further, the heat-resistant organic particles described in JP-B-59-5216, JP-A-59-217755 and the like may be used. Examples of other heat-resistant organic particles include thermosetting urea resins, thermosetting phenol resins, thermosetting epoxy resins, benzoguanamine resins, and the like. Furthermore, it is possible to use precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed during the polyester production process.

  On the other hand, the shape of the particles to be used is not particularly limited, and any of a spherical shape, a block shape, a rod shape, a flat shape, and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color. These series of particles may be used in combination of two or more as required.

  Moreover, the average particle diameter of the particle | grains to be used is 0.01-3 micrometers normally, Preferably it is the range of 0.01-1 micrometer. When the average particle diameter is less than 0.01 μm, the particles are likely to aggregate and dispersibility may be insufficient. On the other hand, when the average particle diameter exceeds 3 μm, the surface roughness of the film becomes too rough and There may be a problem when a release layer is applied in the process.

  Furthermore, the particle content in the polyester layer is usually in the range of 0.001 to 5% by weight, preferably 0.005 to 3% by weight. When the particle content is less than 0.001% by weight, the slipperiness of the film may be insufficient. On the other hand, when the content exceeds 5% by weight, the transparency of the film is insufficient. There is a case.

  The method for adding particles to the polyester layer is not particularly limited, and a conventionally known method can be adopted. For example, it can be added at any stage of producing the polyester constituting each layer, but preferably a polycondensation reaction may be carried out after the esterification stage or after the transesterification reaction.

  Also, a method of blending a slurry of particles dispersed in ethylene glycol or water with a vented kneading extruder and a polyester raw material, or a blending of dried particles and a polyester raw material using a kneading extruder. It is done by methods.

  In addition, in the present invention, in the polyester film constituting the release film, in addition to the above-mentioned particles and fluorescent brightening agent, as long as it does not impair the gist of the present invention, conventionally known antioxidants, Antistatic agents, heat stabilizers, lubricants, dyes, pigments, ultraviolet absorbers and the like can be added and used in combination.

  The thickness of the polyester film constituting the release film of the present invention is not particularly limited as long as it can be formed as a film, but is usually 9 to 188 μm, preferably 12 to 100 μm, for use. is there.

  Next, although the manufacture example of the polyester film in this invention is demonstrated concretely, it is not limited to the following manufacture examples at all.

  First, a method of using the polyester raw material described above and cooling and solidifying a molten sheet extruded from a die with a cooling roll to obtain an unstretched sheet is preferable. In this case, in order to improve the flatness of the sheet, it is necessary to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method are preferably employed. Next, the obtained unstretched sheet is stretched in the biaxial direction. In that case, first, the unstretched sheet is stretched in one direction by a roll or a tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Subsequently, the extending | stretching temperature orthogonal to the extending | stretching direction of the 1st step is 70-170 degreeC normally, and a draw ratio is 3.0 to 7 times normally, Preferably it is 3.5 to 6 times. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C. under tension or relaxation within 30% to obtain a biaxially oriented film. In the above-described stretching, a method in which stretching in one direction is performed in two or more stages can be employed. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges.

  The simultaneous biaxial stretching method can also be adopted for the production of the polyester film in the present invention. The simultaneous biaxial stretching method is a method in which the unstretched sheet is usually stretched and oriented in the machine direction and the width direction at 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is as follows: The area magnification is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times. Subsequently, heat treatment is performed at a temperature of 170 to 250 ° C. under tension or under relaxation within 30% to obtain a stretched oriented film. With respect to the simultaneous biaxial stretching apparatus that employs the above stretching method, a stretching method such as a screw method, a pantograph method, or a linear drive method can be employed.

  Further, a so-called coating stretching method (inline coating: ILC) for treating the film surface during the above-described stretching process of the polyester film can be performed. When a coating layer is provided on a polyester film by a coating stretching method, coating can be performed simultaneously with stretching and the thickness of the coating layer can be reduced according to the stretching ratio, producing a film suitable as a polyester film. it can.

  Regarding the release film in the present invention, examples of a method for imparting light-shielding properties include a method in which a polyester film constituting the release film contains a dye, a pigment, an ultraviolet absorber, and the like.

  In the present invention, the dyes contained in the polyester film constituting the release film can be classified into natural dyes and synthetic dyes, and examples of natural dyes include indigo (indigo). Synthetic dyes include azo dyes, anthraquinone dyes, indigoid dyes, sulfur dyes, triphenylmethane dyes, pyrazolone dyes, stilbene dyes, diphenylmethane dyes, xanthene dyes, alizarin dyes, acridine dyes, quinoneimine dyes (for example, azine dyes, oxazine dyes) , Thiazine dyes), thiazole dyes, methine dyes, nitro dyes, nitroso dyes, cyanine dyes and the like. In the present invention, the pigment to be used can be classified into an organic pigment and an inorganic pigment, and as the organic pigment, quinacridone, phthalocyanine-based, dioxazine-based, anthraquinone-based pigments, Examples include watch angle red and dioxazine violet. Examples of the inorganic pigment include titanium white, zinc white, lead white, carbon black, bengara, vermilion, cadmium red, yellow lead, ultramarine blue, cobalt blue, cobalt purple, zinc chromate and the like.

  These dyes and / or pigments can be used alone or in combination of two or more. The content of these in the polyester film is usually 0.01 to 10% by weight, preferably 0.05 to 7.5% by weight, and more preferably 0.1 to 5% by weight. If the content is less than 0.01% by weight, the degree of coloring is small, and it may be difficult to obtain the desired light shielding properties. On the other hand, if it exceeds 10% by weight, the degree of coloring is saturated, which is not only uneconomical, but also may cause problems such as reduced productivity. In the present invention, it is preferable that the polyester film contains the above-mentioned particles in addition to the dye and / or pigment in a range that does not impair the gist of the present invention in terms of the handleability of the release film.

  Among them, it is preferable to use carbon black particles because the ultraviolet transmittance can be further reduced. In the present invention, when carbon black is contained in the polyester film, specific examples of the carbon black particles to be used include channel black, thermal black, furnace black, and the like. It is 15 to 100 nm, preferably 20 to 70 nm, and more preferably 20 to 50 nm. When the primary particle size of the carbon black particles is less than 15 nm, the particles are easily aggregated, and therefore, the filter life in the extruder is shortened, leading to problems such as deterioration in productivity. Moreover, when the primary particle diameter of the carbon black particles exceeds 100 nm, the degree of roughening of the film surface becomes large, and it becomes difficult to cope with the case where a photocurable resin layer having a smooth surface is formed.

  In the present invention, the content of carbon black particles contained in the polyester film is usually 0.01 to 15% by weight, preferably 0.05 to 7.5% by weight, more preferably 0.1 to 5% by weight. Range. If the content of the particles is less than 0.01% by weight, the slipperiness of the film may be lowered. On the other hand, when the particle content exceeds 15% by weight, the blackness necessary for imparting light shielding properties is saturated, and in addition to being uneconomical, the surface roughness becomes large. When a smooth photo-curing resin is required, it may be difficult to cope with it.

  When the polyester film constituting the release film in the present invention contains an ultraviolet absorber, the ultraviolet absorber is usually contained in the range of 0.2 to 10% by weight, preferably 0.3 to 1.8% by weight. It is preferable to do this. When the ultraviolet absorber content is less than 0.1% by weight, the desired light shielding properties may not be obtained. On the other hand, when the content exceeds 10% by weight, the ultraviolet absorber bleeds out on the surface of the polyester film, which affects the release layer laminated on the polyester film, and may cause problems such as a decrease in releasability.

  Specific examples of ultraviolet absorbers that can be used in the present invention include benzophenone compounds, 1,3,5-triazine compounds, benzoxazinone compounds, and the like, and these may be used alone or in combination of two or more. However, when the color tone is taken into consideration, a benzoxazinone-based compound that does not easily have a yellowish tint is preferably used for the purpose. Specific examples of the benzoxazine-based compound include 2,2- (1,4-phenylene) bis [4H-3,1-benzoxazin-4-one].

  With respect to the method for imparting light-shielding properties to the polyester film constituting the release film in the present invention, each of the above-described methods may be used alone, or two or more types may be used in combination.

  Next, formation of the release layer in the present invention will be described.

  The release layer constituting the release film in the present invention refers to a layer having releasability, and specifically, the peeling force between the acrylic adhesive tape and the release layer (F (A) and F ( Both of B)) are in the range of 15 to 130 mN / cm, preferably 20 to 100 mN / cm for the purposes of the present invention. If the peel force is 15 mN / cm or less, the adhesive property of the photocurable resin is insufficient, and if it exceeds 130 mN /, the adhesive property is too high. There may be a problem when peeling the release film from the cured resin layer.

  Furthermore, the ratio of the normal peel forces on both sides is in the range of 2.0 to 6.0, preferably 2.1 to 5.5, and more preferably 2.2 to 5.0.

  Moreover, the residual adhesive rate of the release layers on both sides is usually 80% or more, and if the residual adhesive rate is low, the slipperiness of the surface of the release layer is high, and thus it tends to cause winding slippage during winding after drying and curing. There is. Further, due to the transferred release layer component, the coating layer may be repelled when there is a coating process or the like in the next process.

  In the release layer of the release film according to the present invention (the one with the larger release force), the residual Si-H ratio is set to 5% or less in order to improve the release property in the photocurable resin layer forming process. It is necessary to suppress. The remaining Si—H ratio is preferably 2% or less, and the remaining Si—H ratio may be 5% or less even in the light release side (the one having a smaller peel force) release layer. In addition, when the residual Si-H ratio of the light release side release layer exceeds 5%, the peelability may be insufficient for the purpose of the present invention.

  The release layer constituting the release film in the present invention may be provided on the polyester film in the film production process such as the above-described coating stretching method (inline coating), and is applied outside the system on the once produced film. So-called off-line coating may be employed, and any method may be employed. The coating stretching method (in-line coating) is not limited to the following, but for example, in sequential biaxial stretching, the first stage of stretching may be completed and the coating treatment may be performed before the second stage of stretching. it can. When a release layer is provided on a polyester film by a coating and stretching method, the film can be applied simultaneously with stretching, and the thickness of the release layer can be reduced according to the stretching ratio. Can be manufactured.

  Moreover, it is preferable that the release layer which comprises the release film in this invention contains a curable silicone resin in order to make mold release property favorable. A type having a curable silicone resin as a main component may be used, or a modified silicone type by graft polymerization with an organic resin such as a urethane resin, an epoxy resin, or an alkyd resin may be used.

  As the type of the curable silicone resin, any of the curing reaction types such as an addition type, a condensation type, an ultraviolet curable type, an electron beam curable type, and a solventless type can be used. Specific examples include KS-774, KS-775, KS-778, KS-779H, KS-847H, KS-856, KS-723A, KS-723B, X-62-2422 manufactured by Shin-Etsu Chemical Co., Ltd. , X-62-2461, X-62-1387, KNS-3051, X-62-1496, KNS320A, KNS316, X-62-1574A / B, X-62-7052, X-62-7028A / B, X -62-7619, X-62-7213, DKQ3-202, DKQ3-203, DKQ3-204, DKQ3-205, DKQ3-210, DKQ3-33061, manufactured by Toray Dow Corning, Momentive Performance Materials Japan GK YSR-3022, TPR-6700, TPR-6720, TPR-672 TPR6500, TPR6501, UV9300, UV9425, XS56-A2775, XS56-A2982, UV9430, TPR6600, TPR6604, TPR6605, manufactured by Toray Dow Corning Co., Ltd. , SP7248S, BY24-452, etc.

  Moreover, the means for setting the peeling force of the release layer to a predetermined value is not particularly limited, and it may be achieved by the thickness of the release layer after curing or the blending of a heavy release agent.

  Specific examples of the heavy release agent include KS-3800 manufactured by Shin-Etsu Chemical Co., Ltd., SDY7292 manufactured by Toray Dow Corning Co., Ltd., BY24-843, BY24-4980, and the like.

  In the present invention, conventionally known coating methods such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating and the like can be used as a method for providing a release layer on the polyester film. Regarding the coating method, there is a description example in “Coating method” published by Yasuharu Harasaki in 1979.

In the present invention, the curing conditions for forming the release layer on the polyester film are not particularly limited. For example, when the release layer is provided by offline coating, it is usually 3 to 120 to 200 ° C. Heat treatment should be performed for 40 seconds, preferably 100 to 180 ° C. for 3 to 40 seconds. Moreover, you may use together heat processing and active energy ray irradiation, such as ultraviolet irradiation, as needed. In addition, a conventionally well-known apparatus and an energy source can be used as an energy source for hardening by active energy ray irradiation. The coating amount of the release layer from the viewpoint of coating property, usually 0.005~1g / ^{m 2,} preferably in the range from 0.005 to 0.5 / ^{m 2.} If the coating amount is less than 0.005 g / m ² , the coating property may be less stable and it may be difficult to obtain a uniform coating film. On the other hand, when the coating is thicker than 1 g / m ² , the coating layer adhesion and curability of the release layer itself may be lowered.

  Further, the polyester film constituting the release film may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

  In the release film of the present invention, the light transmittance in the range of 300 to 375 nm needs to be 0.2% or less, preferably 0.1% or less, and most preferably 0, in order to impart light shielding properties. .05% or less is good. When the light transmittance exceeds 0.2%, a desired pattern accuracy is obtained when a photocurable resin layer is applied on the release surface of the release film, dried, and then subjected to ultraviolet irradiation to form a pattern. It becomes difficult to secure.

  In the release film of the present invention, the method for imparting light shielding properties is not particularly limited, and conventionally known methods can be employed. For example, as described above, a method of containing a dye, a pigment, an ultraviolet absorber and the like in the polyester film constituting the release film is exemplified.

  Next, formation of the photocurable resin layer in the present invention will be described.

  For the photocurable resin layer, unsaturated polyester resin acrylic, addition polymerization, thiol / acrylic hybrid, cationic polymerization, and cationic polymerization and radical polymerization curing components can be used.

  When emphasizing curability, scratch resistance, surface hardness, flexibility and durability, it is preferable to use acrylic materials, which provide antifouling properties, kill resistance, antistatic properties and slipperiness to the surface. In this case, it is preferable to use a cationic copolymer composed of a cationic monomer unit, a hydrophobic monomer unit and an organopolysiloxane unit as main components.

  The acrylic curing component includes an acrylic oligomer and a reactive diluent as an ultraviolet polymerization component, and additionally contains a photopolymerization initiator, a photosensitizer, and a modifier as necessary. May be.

  Acrylic oligomers include polyester (meth) acrylates, epoxy (meth) acrylates, urethane (meth) acrylates, polyethers (meth), including those in which a reactive acryloyl group or methacryloyl group is bonded to an acrylic resin skeleton. ) Acrylate, silicone (meth) acrylate, polybutadiene (meth) acrylate, etc., and those having an acryloyl group or methacryloyl group bonded to a rigid skeleton such as melamine, isocyanuric acid, cyclic phosphazene, etc. It is not limited to these.

  The reactive diluent is a coating agent component having a group that reacts with a polyfunctional or monofunctional acrylic oligomer as well as serving as a solvent in the coating process as a coating medium. It will be. For example, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa ( Examples include (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene glycol (meth) acrylate, propylene glycol di (meth) acrylate, (meth) acryloyloxypropyltriethoxysilane, (meth) acryloyloxypropyltrimethoxysilane, and the like. It is done.

  In the present invention, examples of the ultraviolet ray generation source include a low-pressure mercury lamp, a high-pressure mercury lamp, a xenon lamp, and a metal halide lamp. Further, the method of irradiating with ultraviolet rays may be either batch type or continuous type, and is not particularly limited for the purpose of the present invention.

  In the present invention, the thickness of the photocurable resin layer to be molded is not particularly limited in terms of use, but is preferably 5 to 30 μm, more preferably 10 to 25 μm. If the thickness of the photocurable resin layer is out of any of the above ranges, it may be inappropriate for the purpose of the present invention.

  In the present invention, the light-curing resin to be molded is cast on a surface having a high peel strength (heavy release surface) when it is cast on a release film. It is good to use by the method of protecting the surface after hardening with the surface (light peeling surface) with low peeling force.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. The measuring method used in the present invention is as follows.

(1) Measurement of intrinsic viscosity of polyester 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed are precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added. It was dissolved and measured at 30 ° C.

(2) Measurement of average particle diameter (d ₅₀ : μm) Integration (weight basis) 50% in equivalent spherical distribution measured using centrifugal sedimentation type particle size distribution measuring device (SA-CP3 type manufactured by Shimadzu Corporation) Was the average particle size.

(3) Particle Primary Particle Size After a sample film piece was fixed and molded with an epoxy resin, it was cut with a microtome, and the cross section of the film was observed with a transmission electron microscope. The maximum diameter (a) of particles observed in the film cross section (a) and the diameter (b) orthogonal thereto are measured, the primary particle diameter of one particle is obtained from the following formula, and 500 particles are measured. The arithmetic average was taken as the primary particle size of the particles.
Primary particle size of one particle = (a + b) / 2

(4) Measurement of light transmittance of release film Using a spectrophotometer UV3100 manufactured by Shimadzu Corporation, the light transmittance is continuously measured in the region where the scanning speed is low, the sampling pitch is 2 nm, and the wavelength is 300 to 375 nm. It was taken as the light transmittance.

(5) Evaluation of light-shielding property of release film Using the measurement of the light transmittance obtained in the item (4), the determination was made according to the following criteria.
<Criteria>
○: Maximum light transmittance is less than 0.2% (practical level)
X: Maximum value of light transmittance is 0.2% or more (practical level)

(6) Measurement of release force of release film After attaching one side of a double-sided adhesive tape (Nitto Denko "No. 502") to the release layer surface of an A4 cut-size release film, 50 mm x 300 mm It was cut into a size and the peel strength after standing at room temperature for 1 hour was measured. For the peeling force, a tensile tester (“Intesco model 2001 type” manufactured by Intesco Co., Ltd.) was used, and 180 ° peeling was performed under a tensile speed of 300 mm / min.

(7) Measurement of residual adhesion rate of release film Adhesive tape (Nitto Denko (manufactured by “No. 31B”)) was reciprocated with a 2 kg rubber roller on the silicon cone surface of the sample film, and heated at 100 ° C. for 1 hour. To process. Next, the sample film is peeled off from the pressure-bonded sample, and the adhesive strength of the adhesive tape is measured according to the method of JIS-C-2107 (adhesive strength to stainless steel plate: 180 ° peeling method), and this is defined as residual adhesive strength. . The measurement is performed under conditions of a temperature of 20 ± 2 ° C. and a relative humidity of 65 ± 5%.

(8) Evaluation of remaining Si—H ratio (%) of release layer in release film A sample film corresponding to 40 cm 2 is prepared in advance. Next, cut out to about 5 mm square and place in a 20 cc vial. Further, 4 cc of a saturated butanol solution of potassium hydroxide is added and sealed with a Teflon (registered trademark) tube. Then, it is allowed to stand for 45 minutes in a constant temperature bath at 50 ° C. and 80 ° C., respectively. After cooling to room temperature, the amount of hydrogen gas generated in the vial was quantitatively analyzed by gas chromatography under the following measurement conditions. Using the obtained hydrogen gas generation amount, the residual Si—H ratio (%) was determined by the following formula, and the determination was made according to the following criteria.
* Gas chromatography measurement conditions <Detector>: TCD
<Carrier>: Nitrogen gas <Temperature setting>: Column: 150 ° C.
Injection: 150 ° C
TCD: 150 ° C
Residual Si-H ratio = (amount of generated hydrogen gas (80 ° C. treatment)) × 100 / (amount of generated hydrogen gas (50 ° C. treatment))
The larger the residual Si-H ratio, the more the Si remaining on the surface of the coating after the release layer coating is formed.
Since there is much H group amount, the adhesiveness with respect to the photocurable resin layer manufactured in this invention comes to improve.
<Criteria>
○: Residual Si—H ratio (%) is 5% or less and good peelability (practical level)
X: Since the residual Si-H ratio (%) exceeds 5%, the peelability is poor (practical level).

(9) Coating film adhesion promotion evaluation of release film (practical property substitution evaluation)
The sample film was left in a constant temperature and humidity chamber at 60 ° C. and 70% RH for 48 hours, and then the sample film was taken out. Thereafter, the release surface of the sample film was rubbed with a tentacle five times, and the degree of release of the release layer was determined according to the following criteria.
<Criteria>
○: No dropout of the coating film (practical level)
Δ: The coating film turns white but does not fall off (practical level)
×: Detachment of the coating film was confirmed (practically difficult level)

(10) Evaluation of processability of UV curable resin layer (practical property substitution evaluation)
On the heavy release side release layer of the release film, a resin composition composed of the following ultraviolet curable resin composition was dried with hot air at 120 ° C. for 30 seconds, and then applied to a coating thickness (after drying) of 20 μm. . Thereafter, while pressing a mold having a quadrangular pyramid shape (bottom length is 50 μm, width is 150 μm, top surface is 50 μm, width is 100 μm, height is 20 μm) against the resin coating surface side, the resin coating surface side Thus, ultraviolet irradiation was performed under an irradiation amount of 120 mJ / cm 2 to obtain an ultraviolet curable resin layer having the lens pattern shape shown in FIG. 35 of JP-A-2006-30621. Next, the release film was peeled off. The processability in a series of manufacturing processes was determined according to the following criteria.

(11) Peelability evaluation of ultraviolet curable resin layer After applying an ultraviolet curable resin layer having the following composition on an A4 cut size release film (A) in advance so that the coating thickness (after drying) is 5 μm, Heat treatment was performed at 80 ° C. for 1 minute. Next, ultraviolet irradiation was performed under the following ultraviolet irradiation conditions. After cooling to room temperature, an A4 cut-size release film (B) was placed on the surface and bonded together with a rubber roller with a load of 2 kg.
The release film (B) was peeled from the ultraviolet curable resin layer by hand from the sample, and the peelability was evaluated according to the following criteria.
<< UV curable resin composition >>
UV curable resin: KAYANOBA FOP5000 manufactured by Nippon Kayaku
<Ultraviolet irradiation conditions>
Equipment: “UVC-402 type” manufactured by USHIO
Line speed: 5 m / min Line output: 120 w / cm
Irradiation distance: 10cm
<< UV curable resin peelability, criteria >>
○: The release film B is smoothly peeled off without being caught, and at the same time, does not float from the release film A (practical level).
Δ: Although the release film B is slightly caught, it peels off smoothly, and at the same time, it does not float from the release film A. (Practical level>
Alternatively, the release film A peels off smoothly, but at the same time the release film B slightly floats (practical level)
X: The release film B is strongly peeled off and does not peel off smoothly, or is lifted from the release film A (practical level)

(12) Winding property of photo-curable resin after UV irradiation The photo-curing resin is cast on the release layer on the heavy release side of the release film, and the winding property of the resin cured after UV irradiation is as follows. Judged according to.
《Windability of photo-curing resin after UV irradiation, criterion》
○: When winding the film after application of the photocurable resin into a roll with a tension of 200 N / m, there is no meandering in the middle of winding or winding deviation on the end face of the roll after winding. Careful handling is required because the roll end face does not shift after winding or winding in the same way during winding. ×: Rolling easily after winding or winding in the same way as above If any of the deviations are seen on the end face

(13) Comprehensive evaluation Based on the evaluation result in each item of the sample film, the determination was made according to the following criteria.
<Criteria>
○: The light transmittance is 0.1% or less, the residual Si—H ratio is 2% or less, the ratio of the peel strengths on both sides is 2.2 times or more and 5.0 times or less, and the residual adhesion rate is 95%. That is above, UV curable resin peelability is ○, and photocurable resin winding property is ○ (practical level)
Δ: The light transmittance is 0.2% or less, the residual Si—H ratio is more than 2% and 5% or less, and the ratio of the peeling forces on both sides is 2.0 times or more and 6.0 times or less, Residual adhesion rate is 95% or more, UV curable resin peelability is ◯, and photocurable resin winding property is △ (practical level) × ×: light transmittance exceeds 0.2%, or Since the residual Si-H ratio exceeds 5%, the light-shielding property is unsuitable, the ratio of the peeling forces on both sides is less than 2.0 times or more than 6.0 times, and the residual adhesion ratio on the light peeling surface is 80%. The peel strength of the heavy release surface exceeds 130 mN / cm, the UV curable resin peelability is x, and the rollability of the photocurable resin is x (practical level).
The polyester used in the examples and comparative examples was prepared as follows.

<Manufacture of polyester>
Production Example 1 (Polyethylene terephthalate A)
100 parts of dimethyl terephthalate, 60 parts of ethylene glycol and 0.09 part of magnesium acetate tetrahydrate are placed in a reactor, the temperature is raised by heating, methanol is distilled off, transesterification is performed, and 4 hours are required from the start of the reaction. The temperature was raised to 230 ° C. to substantially complete the transesterification reaction. Next, 0.04 part of ethylene glycol slurry ethyl acid phosphate, 0.03 part of antimony trioxide and 0.01 part of silica particles having an average particle diameter of 1.5 μm were added, and then the temperature was 280 ° C. and the pressure was increased in 100 minutes. The pressure reached 15 mmHg, and the pressure was gradually reduced thereafter to finally reach 0.3 mmHg. After 4 hours, the system was returned to normal pressure to obtain polyethylene terephthalate A having an intrinsic viscosity of 0.61.

Production Example 2 (Polyethylene terephthalate B)
99.3 parts of polyethylene terephthalate A produced in Production Example 1 and 0.6 part of carbon black particles having a primary particle diameter of 20 nm were dry blended and extruded using a biaxial kneading extruder to obtain polyethylene terephthalate B. The intrinsic viscosity of the obtained polyethylene terephthalate (B) was 0.60.

Production Example 3 (Polyethylene terephthalate C)
97.5 parts of polyethylene terephthalate A produced in Production Example 1 and 2.5 parts of titanium oxide particles having an average particle size of 0.35 μm are dry blended and extruded using a twin-screw kneading extruder to obtain polyethylene terephthalate C. It was. The intrinsic viscosity of the obtained polyethylene terephthalate (C) was 0.61.

Example 1:
The polyethylene terephthalate B produced in Production Example 2 was dried at 180 ° C. for 4 hours in an inert gas atmosphere, melted at 290 ° C. by a melt extruder, extruded from a die, and the surface temperature was adjusted to 40 using an electrostatic application adhesion method. The sheet was cooled and solidified on a cooling roll set to ° C. to obtain an unstretched sheet. First, the obtained unstretched sheet was stretched 3.6 times in the MD direction at 95 ° C., then led to a tenter, and sequentially biaxially stretched 4.3 times in the TD direction. Thereafter, it was heat-set at 230 ° C. for 3 seconds to obtain a PET film having a thickness of 50 μm. Next, offline, a release agent having the composition described in the following release layer (1) was applied by a reverse gravure coating method so that the coating amount (after drying) was 0.1 g / m 2, and then 180 ° C., 10 ° C. After drying for 2 seconds, the film was wound on a roll to obtain a single-sided release film. The obtained single-sided release film was unwound, and the release layer having the composition described in the following release layer (2) was processed in the same manner on the opposite surface where the release layer was previously provided to obtain a double-sided release film. It was.

<Release layer (1): Composition of silicone resin liquid (C)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 14 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Heavy release agent (KS-3800; Shin-Etsu) 6 parts by weight curing agent (PL-5000; manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

<Release layer (2): Composition of silicone resin liquid (A)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 20 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Curing agent (PL-5000; Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluting solvent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

Example 2:
In Example 1, except that the release layer had the following release agent composition, it was produced in the same manner as in Example 1 to obtain a double-sided release film.
<Release layer (1): Composition of silicone resin liquid (D)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 12 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Heavy release agent (KS-3800; Shin-Etsu) 8 parts by weight curing agent (PL-5000; manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

<Release layer (2): Composition of silicone resin liquid (A)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 20 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Curing agent (PL-5000; Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluting solvent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

Example 3:
In Example 1, except that the release layer had the following release agent composition, it was produced in the same manner as in Example 1 to obtain a double-sided release film.
<Release layer (1): Composition of silicone resin liquid (E)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 10 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Heavy release agent (KS-3800; Shin-Etsu) 10 parts by weight curing agent (PL-5000; manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

<Release layer (2): Composition of silicone resin liquid (B)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 16 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Heavy release agent (KS-3800; Shin-Etsu) 4 parts by weight curing agent (PL-5000; manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

Comparative Example 1:
In Example 1, except that the release layer had the following release agent composition, it was produced in the same manner as in Example 1 to obtain a double-sided release film.
<Release layer (1): Composition of silicone resin liquid (B)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 16 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Heavy release agent (KS-3800; Shin-Etsu) 4 parts by weight curing agent (PL-5000; manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

<Release layer (2): Composition of silicone resin liquid (A)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 20 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Curing agent (PL-5000; Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluting solvent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

Comparative Example 2:
In Example 1, except that the release layer had the following release agent composition, it was produced in the same manner as in Example 1 to obtain a double-sided release film.
<Release layer (1): Composition of silicone resin liquid (C)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 14 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Heavy release agent (KS-3800; Shin-Etsu) 6 parts by weight curing agent (PL-5000; manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

<Release layer (2): Composition of silicone resin liquid (H)>
Cured silicone resin (DKQ3-3061; manufactured by Toray Dow Corning) 50 parts by weight Curing agent (SRX67; manufactured by Toray Dow Corning) 0.7 parts by weight Diluent: methyl ethyl ketone / toluene mixed solvent 550 parts by weight

Comparative Example 3:
In Example 1, except that the release layer had the following release agent composition, it was produced in the same manner as in Example 1 to obtain a double-sided release film.
<Release layer (1): Composition of silicone resin liquid (F)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 6 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Heavy release agent (KS-3800; Shin-Etsu) 14 parts by weight Curing agent (PL-5000; manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

<Release layer (2): Composition of silicone resin liquid (B)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 16 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Heavy release agent (KS-3800; Shin-Etsu) 4 parts by weight curing agent (PL-5000; manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

Comparative Example 4:
In Example 1, except that the release layer had the following release agent composition, it was produced in the same manner as in Example 1 to obtain a double-sided release film.
<Release layer (1): Composition of silicone resin liquid (I)>
Cured silicone resin (KS-3703; manufactured by Shin-Etsu Chemical Co., Ltd.) 29 parts by weight Heavy release agent (KS-3800; manufactured by Shin-Etsu Chemical Co., Ltd.) 70 parts by weight Curing agent (PL-5000; manufactured by Shin-Etsu Chemical Co., Ltd.) 1 weight Part Diluent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

<Release layer (2): Composition of silicone resin liquid (F)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 6 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Heavy release agent (KS-3800; Shin-Etsu) 14 parts by weight Curing agent (PL-5000; manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

Comparative Example 5:
A PET film was obtained in the same manner as in Example 1 except that the polyethylene terephthalate C produced in Production Example 3 was used. Next, offline, a release agent having the composition described in the following release layer (1) was applied by a reverse gravure coating method so that the coating amount (after drying) was 0.1 g / m 2, and then 180 ° C., 10 ° C. After drying for 2 seconds, the film was wound on a roll to obtain a single-sided release film. The obtained single-sided release film was unwound, and the release layer having the composition described in the following release layer (2) was processed in the same manner on the opposite surface where the release layer was previously provided to obtain a double-sided release film. It was.

<Release layer (1): Composition of silicone resin liquid (G)>
Cured silicone resin (DKQ3-3061; manufactured by Toray Dow Corning) 50 parts by weight Cured silicone resin (SH21PA; manufactured by Toray Dow Corning) 0.3 parts by weight Curing agent (SRX67; manufactured by Toray Dow Corning) 0. 7 parts by weight diluent solvent: 550 parts by weight of methyl ethyl ketone / toluene mixed solvent

<Release layer (2): Composition of silicone resin liquid (A)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 20 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Curing agent (PL-5000; Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluting solvent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

Comparative Example 6:
A PET film was obtained in the same manner as in Example 1 except that the polyethylene terephthalate A produced in Production Example 1 was used. Next, offline, a release agent having the composition described in the following release layer (1) was applied by a reverse gravure coating method so that the coating amount (after drying) was 0.1 g / m 2, and then 180 ° C., 10 ° C. After drying for 2 seconds, it was wound on a roll to obtain a single-sided release film. The obtained single-sided release film was unwound, and the release layer having the composition described in the following release layer (2) was processed in the same manner on the opposite surface where the release layer was previously provided to obtain a double-sided release film. It was.

<Release layer (1): Composition of silicone resin liquid (C)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 14 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Heavy release agent (KS-3800; Shin-Etsu) 6 parts by weight curing agent (PL-5000; manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent

<Release layer (2): Composition of silicone resin liquid (A)>
Cured silicone resin (X-62-5039; manufactured by Shin-Etsu Chemical Co., Ltd.) 20 parts by weight Cured silicone resin (X-92-185; manufactured by Shin-Etsu Chemical Co., Ltd.) 0.4 parts by weight Curing agent (PL-5000; Shin-Etsu Chemical Co., Ltd.) 1 part by weight Diluting solvent: 700 parts by weight of methyl ethyl ketone / toluene mixed solvent The results obtained are summarized in Tables 1 and 2 below.

  The film of the present invention is suitably used, for example, for the production of various display components, such as for the production of LCD components such as polarizing plates and retardation plates used in LCDs, for the production of PDP components, and for the production of organic EL components. can do.

Claims (1)

Each of the release films having different release forces on both sides of the polyester film has a light transmittance of 0.2% or less in the wavelength region of 300 to 375 nm, and the residual Si on the release layer surface having the higher release force. -H ratio is 5% or less, the release force of the release layer is 2.0 to 6.0 times the release force of the other release layer, and the residual adhesion rates of both release layers are both A release film for producing an optical member, characterized by being 80% or more.