JP2013052553A - Mold release film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antistatic performance, a small amount of oligomer precipitation, a good long-term durability adhesion, a small change in peeling with time of a peeling force from an adhesive tape, and for various display component production and various adhesive layer protecting applications. A suitable release film is provided.
A release film in which a coating layer and a release layer are sequentially provided on one side of a polyester film stretched at least in a uniaxial direction, and the coating layer contains an organic compound containing zirconium and an organosilicon compound. The surface specific resistance (R) on the surface of the release layer is 10 ¹² or less, the peel force between the acrylic adhesive tape and the release layer is 30 to 60 mN / cm, and the release film in a 20 ml vial A release film for protecting a pressure-sensitive adhesive layer, characterized in that the amount of hydrogen gas generated after immersing (40 cm ² ) in a butanol solution containing 5% by weight of potassium hydroxide and heat-treating at 50 ° C. for 1 hour is 40 ppm or less. .
[Selection figure] None

Description

  The present invention relates to a release film having a very low oligomer precipitation amount, good antistatic performance, as little as possible variation in peeling over time, and good long-term durability adhesion, for protecting an adhesive layer. It is particularly suitable when a peeling force region of about 30 to 60 mN / cm is required for the peeling force with an acrylic adhesive tape. For example, a polarizing plate used in a liquid crystal display (hereinafter abbreviated as LCD), For manufacturing various display components such as for manufacturing LCD components such as phase difference plates, for manufacturing plasma display panel (hereinafter abbreviated as PDP) components, for manufacturing organic electroluminescence (hereinafter abbreviated as organic EL) components, etc. In addition, the present invention relates to a release film suitable for various adhesive layer protecting applications.

  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. Etc. are used. As a problem in the use of a release film, it is mentioned that, after application of the pressure-sensitive adhesive layer, fluctuations in peeling over time (heavy peeling) cause various problems.

  In recent years, with the advancement of IT (Information Technology) field, various problems associated with heavy peeling in the adhesive layer protection application as well as the improvement of the quality of release films used when manufacturing display members such as LCD, PDP, and organic EL. It is in a situation that becomes apparent.

  In order to cope with the various applications described above, it was desired to not only have excellent mold release properties but also to minimize the variation in peeling over time.

  For example, taking a manufacturing process of a polarizing plate for LCD as an example, the manufacturing process includes a process in which a release film and a polarizing plate are bonded together via an adhesive layer and wound into a roll. With the improvement of the property, the design of the release layer may need to be changed for reasons such as changing the composition of the pressure-sensitive adhesive layer used. For example, in the case where a peel force region with an acrylic adhesive tape of about 30 to 60 mN / cm is required, when designing a release film having the peel force region, by using a release control agent in combination In order to reach the target peeling force region, there is a method of adjusting the blending amount. However, while this method reaches the target level with the initial adhesive tape, the adhesive layer is applied on the release layer by the so-called transfer method, and then the peeling fluctuation occurs over time. There was a tendency for heavy peeling. Furthermore, the magnitude of the change in peeling over time is not long after applying a pressure-sensitive adhesive layer on the release film for a long period of time and leaving it in a state of being bonded to an untreated PET film. There was an inconvenience to not. For this reason, today, it has not always been a satisfactory situation when used for FPD fields where technological innovation is remarkable.

  On the other hand, in touch panel applications, more precise parts have been used as electronic components to be mounted in response to improvements in operability of touch panels. The adhesive is easily affected by the electric charge charged.

  As described above, for example, while satisfying a peeling force region of about 30 to 60 mN / cm with a peeling force by an acrylic adhesive tape, the contradictory characteristics of minimizing peeling fluctuation (heavy peeling) with time are made compatible. It was in a situation where it was necessary. Further, it is necessary to suppress the influence of static electricity and peeling electrification on the electronic component as an additional requirement.

  In recent years, with the advancement of IT (Information Technology) field, various defects associated with the precipitation of oligomers have become apparent along with the improvement of the quality of release films used in the production of LCD, PDP, organic EL and other display members. is there.

  In order to cope with the various uses described above, it is desired not only to have excellent mold releasability, but also to minimize foreign matter on the film surface. In other words, since it is also an application that places importance on so-called visibility, especially through light transmission, even a foreign matter on the film surface that is not a problem at all in a normal film application becomes a serious problem.

  For example, when the manufacturing process of a polarizing plate for LCD is given as an example, the manufacturing process includes a process in which a release film and a polarizing plate are bonded together via an adhesive layer and wound into a roll. Is considered to precipitate through a drying process after application of the adhesive. The oligomer deposited on the surface of the release layer is obtained when the LCD is manufactured by transferring the polarizing plate with the pressure-sensitive adhesive layer to which the oligomer is adhered to the glass substrate, by transferring to the surface of the opposite pressure-sensitive adhesive layer. In some cases, the brightness of the LCD is reduced.

  In recent years, there is a tendency to increase the brightness of the display screen for the purpose of improving the visibility of the LCD, and the above-mentioned problems have become serious problems.

  On the other hand, with the aim of reducing the manufacturing cost accompanying productivity improvement, there is a tendency to set the drying temperature higher in the drying process, especially with the speeding up of the manufacturing process, and the above-mentioned oligomer is more likely to precipitate. It has become.

  In the inspection process that involves optical evaluation such as display capability, hue, contrast, and foreign matter contamination of LCD polarizing plates, measures to prevent the outflow of defective products by visual or magnifying glass are taken. When the attached release film is used, it is judged as a defective product due to foreign matter mixing, and has a problem that a defect such as a decrease in product yield occurs.

JP-A-5-194768 JP-A-9-323392 Japanese Patent Laid-Open No. 52-3030 JP-A-9-59041 Japanese Patent Application No. 2010-56884 Japanese Patent Application No. 2010-121101 Japanese Patent Application No. 2010-97765 Japanese Patent Application No. 2010-97925 Japanese Patent Application No. 2010-165733 Japanese Patent Application No. 2011-48410 Japanese Patent Application No. 2011-75120

  The present invention has been made in view of the above circumstances, and the solution is to have good antistatic performance, extremely low oligomer precipitation amount, good long-term durability adhesion, especially peeling from acrylic adhesive tape. When a peeling force region of about 30 to 60 mN / cm is required by force, it becomes possible to provide a release film with as little peeling fluctuation (heavy peeling) as possible, such as a polarizing plate for LCD, To provide a release film suitable for various adhesive component protection applications in addition to the production of various display components, such as for the production of liquid crystal components such as retardation plates, the production of PDP components, the production of organic EL components, etc. It is in.

  As a result of intensive studies in view of the above circumstances, the present inventors have found that the above problem can be easily solved by a release film having a specific configuration, and have completed the present invention.

That is, the gist of the present invention is a release film in which a coating layer and a release layer are sequentially provided on one side of a polyester film stretched at least in a uniaxial direction, and the coating layer includes an organic compound containing zirconium, and organic silicon. The surface specific resistance (R) of the release layer surface is 10 ¹² or less, the peeling force between the acrylic adhesive tape and the release layer is 30 to 60 mN / cm, and in a 20 ml vial bottle Protecting the pressure-sensitive adhesive layer, wherein the release film (40 cm ² ) is immersed in a butanol solution in which 5% by weight of potassium hydroxide is dissolved and heat-treated at 50 ° C. for 1 hour, the amount of hydrogen gas generated is 40 ppm or less It exists in a release film.

  According to the release film of the present invention, it becomes possible to provide a release film having a small amount of oligomer precipitation, good antistatic performance, minimal fluctuation in peeling over time, and good long-term durability adhesion. Suitable for manufacturing various display components, for example, for manufacturing liquid crystal components such as polarizing plates for LCDs and retardation plates, for manufacturing PDP components, for manufacturing organic EL components, etc. Can provide a good release film, 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 structure or a two-layer structure as long as it does not exceed the gist of the present invention other than the two-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 kind of the particle to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness. Specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Examples of the particles include magnesium, 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, during the polyester production process, it is possible to use precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed. On the other hand, the shape of the particles to be used is not particularly limited. Either a rod shape or a flat shape may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. 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.

  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 to the above-mentioned particles, conventionally known antioxidants, antistatic agents, thermal stabilizers, lubricants, dyes, pigments, and the like can be added to the polyester film in the present invention as necessary.

  Although the thickness of the polyester film which comprises the release film of this invention will not be specifically limited if it is a range which can be formed into a film, Usually, 5-250 micrometers, Preferably it is the range of 5-188 micrometers.

  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 simultaneously in the machine direction and the width direction in a state of temperature control at 70 to 120 ° C., preferably 80 to 110 ° C. 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-described stretching method, conventionally known stretching methods such as a screw method, a pantograph method, and a linear drive method can be employed.

  Furthermore, a so-called coating stretching method (in-line coating) in which the film surface is treated during the above-described polyester film stretching step can be applied. 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.

  Next, formation of the coating layer which comprises the release film in this invention is demonstrated. Regarding the coating layer, the above-described coating stretching method (in-line coating) may be used, so-called off-line coating that is applied outside the system on a once produced film may be employed, and any method may be employed. .

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

  The present invention makes it an essential requirement to contain an organic compound containing zirconium in the coating layer.

  Specific examples of the organic compound having a zirconium element include zirconium acetate, zirconium normal propyrate, zirconium normal butyrate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium bisacetylacetonate and the like.

  The amount of the zirconium compound contained in the coating layer is usually 0.001 to 70% by weight, preferably 1 to 30% by weight, and more preferably 1 to 4% by weight. When the amount of the zirconium compound is 0.001% by weight or less, the curing reaction of the coating layer does not proceed rapidly, and the long-term durability adhesion of the coating film on the release surface after forming the release layer on the coating layer May get worse.

  Among them, an organic compound having a chelate structure is preferable with respect to an organic compound containing zirconium, particularly in that the ability to prevent oligomer precipitation is favorable. It is also described in detail in the “Crosslinking agent handbook” (Yamashita Shinzo, Kaneko East Assistant Editor, Taiseisha, 1990 edition).

  The coating layer constituting the release film of the present invention has an essential requirement to use an organosilicon compound together in order to improve oligomer precipitation prevention and good antistatic performance. In particular, it is preferable to use a condensation polymer of an alkoxysilane compound and / or a partial hydrolyzate thereof.

As the alkoxysilane compound, a compound of the general formula Si (OR1) x (R2) 4-x is used. In the above general formula, x is preferably an integer of 2 to 4. In the above general formula, R1 is either an alkyl group or an acyl group. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, a tert-butyl group and the like, and an acyl group. Is, for example, an acyl group having 1 to 4 carbon atoms such as an acetyl group.

In the above general formula, R2 is an organic group having 1 to 10 carbon atoms, for example, an unsubstituted or substituted hydrocarbon group. Examples of the unsubstituted hydrocarbon group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, tert-butyl group, n-hexyl group, cyclohexyl group, n-octyl group, and tert- Examples thereof include alkyl groups such as octyl group and n-decyl group, aryl groups such as phenyl group, alkenyl groups such as vinyl group and allyl group. Examples of the substituted hydrocarbon group include γ-glycidoxypropyl group, γ-mercaptopropyl group, 3,4
-Epoxy cyclohexyl ethyl group, (gamma) -methacryloyloxypropyl group, etc. are mentioned. These alkoxysilane compounds are used individually by 1 type or in combination of 2 or more types.

Examples of the alkoxysilane compound with x = 4 include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, and tetra-acetoxysilane. Examples of the alkoxysilane compound of x = 3 include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, i-propyltrimethoxysilane. I-propyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloyloxypropyltri Methoxysilane, γ-mercaptopropyltriethoxysilane, phenyltrimethoxysilane, vinyltriethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane, 3,4-epoxycyclohexyl Triethoxysilane, and the like. Examples of the alkoxysilane compound of x = 2 include dimethyldimethoxysilane, dimethyldiethoxysilane, methylphenyldimethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, di-n-propyldimethoxysilane, di-n-propyldiethoxysilane, Examples include di-i-propyldimethoxysilane, di-i-propyldiethoxysilane, diphenyldimethoxysilane, and divinyldiethoxysilane.

  Further, inorganic particles may be contained for the purpose of improving the adhesion and slipperiness of the coating layer, and specific examples include silica, alumina, kaolin, calcium carbonate, titanium oxide, barium salt and the like.

  Moreover, an antifoamer, a coating property improving agent, a thickener, an organic lubricant, organic polymer particles, an antioxidant, a UV absorber foaming agent, a dye, and the like may be contained as necessary.

  In the range not exceeding the gist of the present invention, only one type of organic solvent may be used for the purpose of improving dispersibility, improving film forming property, etc., and two or more types may be used as appropriate.

The coating amount of the coating layer provided on the polyester film constituting the release film of the present invention (after drying) typically, 0.005~1g / ^{m 2,} the range preferably from 0.005 to 0.5 / ^{m 2} It is. When the coating amount (after drying) is less than 0.005 g / m ² , the uniformity of coating thickness may be insufficient, and the amount of oligomer deposited from the coating layer surface may increase after heat treatment. . On the other hand, when the coating is applied in excess of 1 g / m ² , problems such as a decrease in slipperiness may occur.

  In the present invention, as a method for providing the coating layer, a conventionally known coating method such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating or the like can be used. As for the coating method, there is a description example in “Coating method” published by Yoji Harasaki in 1979.

  In the present invention, the curing conditions for forming the coating layer on the polyester film are not particularly limited. For example, when the coating layer is provided by off-line coating, usually at 60 to 200 ° C. for 3 to 40 seconds. The heat treatment is preferably performed at 80 to 180 ° C. for 3 to 40 seconds as a guide. Moreover, you may use together heat processing and active energy ray irradiation, such as ultraviolet irradiation, as needed.

  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. Specifically, the peel force (F) between the acrylic adhesive tape and the release layer is 30 to 90 mN / It is necessary to be cm, and preferably 30 to 60 mN / cm.
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, X-62-2422, X-62-2461, X-62- manufactured by Shin-Etsu Chemical Co., Ltd. 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, Toray Dow Corning SRX357, SRX211, SD7220, LTC750A, LTC760A, SP7259, BY24-468C, SP7248S, BY24-45DKQ3-202, DKQ3-203, DKQ3-204, DKQ3-205, DKQ3-210, Momentive Performance Material YSR-3 22, TPR-6700, TPR-6720, TPR-6721, TPR6500, TPR6501, UV9300, UV9425, XS56-A2775, XS56-A2982, UV9430, TPR6600, TPR6604, TPR6605, manufactured by Toray Dow Corning Co., Ltd. The Further, a release control agent may be used in combination to adjust the release property of the release layer.

  Specific examples of the release control agent include KS3800 manufactured by Shin-Etsu Chemical Co., Ltd., SD7292, Toray Dow Corning, 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, and when providing the release layer by off-line coating, usually at 120 to 200 ° C. for 3 to 40 seconds, The heat treatment is preferably performed at 100 to 180 ° C. for 3 to 40 seconds as a guide. 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 is usually from 0.005 to 1 g / m ² , preferably from 0.005 to 0.5 g / m ² , more preferably from 0.01 to 0.2 g / m from the viewpoint of coatability. ^{There are two} ranges. 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.

  The release film thus obtained was immersed and heat-treated (50 ° C. × 1 hour) using a butanol solution in which 5% by weight of potassium hydroxide was dissolved after the release film was produced for 24 hours. It is necessary to suppress the amount of hydrogen gas generated from the mold film to 40 ppm or less. Preferably it is 30 ppm or less. When the amount of generated hydrogen gas exceeds 40 ppm, when left in a state where the pressure-sensitive adhesive layer and the release layer of the release film are pasted together, there is a large change in peeling over time, and in the scene that needs to be peeled off, Problems such as difficulty in peeling occur.

  In the release film of the present invention, as a specific method for suppressing the hydrogen gas generation amount to 40 ppm or less, for example, in the case of using a release control agent for the purpose of adjusting the release of the release layer, it is derived from a crosslinking agent. Examples include a method of selecting a type having a small amount of Si—H groups.

  Conventionally, as a technique for making a peeling force heavy peel by those skilled in the art, a technique commonly used for the purpose of increasing the amount of Si—H groups derived from a crosslinking agent is used. However, this method tends to increase the peeling fluctuation as the amount of Si—H groups derived from the crosslinking agent decreases with time. Therefore, if the release layer and the adhesive layer of the release film are stored in a state of being bonded together for a long time after applying the adhesive, it may cause problems such as heavy release when the release film is peeled off. become.

  In order to improve such problems, the present inventors have previously made a Si-H derived from a butanol solution in which 5% by weight of potassium hydroxide is dissolved and a crosslinking agent in the release layer in an initial stage immediately after the release film processing. By using the reaction with the group and quantitatively evaluating the amount of hydrogen gas generated after the reaction, it is possible to determine the presence or absence of an inhibitory effect on peeling fluctuation over time by using it as an evaluation index for peeling stability.

In the release film of the present invention, the surface specific resistance (R) of the release layer surface needs to be 10 ¹² (Ω) or less in order to suppress the influence of static electricity, peeling charge, etc. on the electronic component, Is preferably 10 ¹¹ (Ω) or less. When the R value exceeds 10 ¹² (Ω), peeling electrification occurs when the release film is peeled off. For example, after processing the pressure-sensitive adhesive, problems such as peeling electrification occur when the release film is peeled off.

Regarding the coating layer constituting the release film in the present invention, it is a material that can be applied on the polyester film and the surface specific resistance (R) of the release layer surface can satisfy 10 ¹² (Ω) or less. If it is, conventionally well-known material can be used and it does not necessarily limit. For example, there is a description example in the supervision of Kiyoshi Akamatsu, a popular edition “Technology and Application of Antistatic Materials” published in July 2002 by CMC Publishing Co., Ltd.

  As specific examples, a coating layer composed of a siloxane hydrolyzate or a coating layer containing a polyaniline-based, polypyrrole-based, or thiophene-based conductive polymer material is used as a constituent material of the release film of the present invention. be able to.

  Regarding the release film in the present invention, a coating layer such as an adhesive layer, an antistatic layer and an oligomer precipitation preventing layer may be provided on the surface where the release layer is not provided, as long as the gist of the present invention is not impaired.

  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 present invention, when a release layer is provided on the coating layer, the film may be temporarily wound after the coating layer is provided, and the release layer may be provided again. In addition, after the coating layer is provided, the release layer is continuously released. A mold layer may be provided on the coating layer, and any method may be adopted.

After the release film of the present invention is heat-treated (180 ° C., 10 minutes), the amount of oligomer (OL) extracted from the release layer surface with dimethylformamide is preferably 2.0 mg / m ² or less. Preferably it is 1.0 mg / m ² or less, particularly preferably 0.3 mg / m ² or less. When the OL exceeds 2.0 mg / m ² , for example, when the liquid crystal component is manufactured, the adhesive layer is used for protecting the adhesive layer, the transparency of the adhesive is lowered, the adhesive strength of the adhesive layer is reduced, or optical evaluation is performed. There may be problems such as causing trouble in the accompanying inspection process.

  In the present invention, “oligomer” is defined as a cyclic trimer of low molecular weight substances that crystallize and precipitate on the film surface after heat treatment.

  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) Release force (F) measurement of release film Affixed with one side of a double-sided adhesive tape (Nitto Denko “No. 502”) on the release layer surface of the sample film, then cut into a size of 50 mm × 300 mm Measure the peel force after standing at room temperature for 1 hour. 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.
Thereafter, the peeling condition was determined according to the following criteria.
<Criteria>
○: A range of 30 to 60 mN / cm. Peeling is good (practical level)
X: Less than 30 mN / cm or more than 60 mN / cm, peeling condition is poor (practically problematic level)

(4) Determination of the amount of hydrogen (H ₂ ) gas generated from the release film after heat treatment A sample film of 40 cm ² is cut out in advance and weighed. Again cut out amount to be used for measuring the ^second corner 5 mm, filling the sample film in 20ml vial bottle gas chromatography only (approximately 0.213g with a release film of 38 [mu] m). Next, 3 ml of a butanol solution in which 5% by weight of potassium hydroxide is dissolved (prepared by adding 1 g of potassium hydroxide to 19 g of butanol) is sampled with a pipetter, and the entire sample film is immersed in a 5% by weight of potassium hydroxide butanol solution. Add as follows. Thereafter, the vial is sealed with a crimper, and heat-treated at 50 ° C. for 1 hour using a heating block (model: HF21, manufactured by Yamato Kagaku). Then, using the following gas chromatography measuring apparatus, the amount of hydrogen (H ₂ ) gas generated from the sample film was quantitatively analyzed and judged according to the following criteria.
<< Gas chromatography measurement conditions >>
Equipment: EAGanalyzer (SENSORTEC Co, Ltd)
Measurement condition:
Pressure Gauge Low: 0.05 MPa
High: 0.05 MPa
Column temperature: 50 ° C
Column flow rate: 30.0sccm
Syringe injection volume: 1cc
Measurement time: 5 minutes << Criteria >>
A: 30 ppm or less (practical level, particularly good)
○: 40 ppm or less (practical level)
×: Exceeding 40 ppm (practical level)

(5) Measurement of amount of metal element from release surface side of release film Fluorescent X-ray measurement apparatus (Shimadzu Corp. model “XRF-1500” from the surface provided with the release layer of the sample sample in advance. The amount of metal elements was measured by the FP (Fundamental Parameter Method) method under the measurement conditions described in the following table.

(6) Evaluation of peel force change amount (ΔF) of release film / Measurement method of peel force (F1) Baker type so that the coating amount is 2 mil on a sample film in advance with an adhesive layer composed of the following adhesive composition Application was performed using an applicator, and heat treatment was performed at 150 ° C. for 3 minutes using a hot air circulation furnace, and the untreated PET film 188 μm and the adhesive layer of the adhesive layer with the sample film were bonded together with a 2 kg rubber roller. Next, the bonded sample film was allowed to stand at room temperature (23 ° C. ± 2 ° C., 50% RH ± 5% RH) for 24 hours. Thereafter, the sample film is cut into a size of 50 mm × 300 mm, and the peel force after standing for 1 hour at room temperature is 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.
・ Measuring method of peel force (F2) Apply a pressure sensitive adhesive layer composed of the following pressure sensitive adhesive composition to a sample film in advance using a baker type applicator so that the coating amount (before drying) is 2 mil, hot air circulation furnace Then, heat treatment was performed at 150 ° C. for 3 minutes, and the untreated PET film 188 μm and the adhesive layer of the adhesive layer with the sample film were bonded together with a 2 kg rubber roller. Next, the bonded sample film was left in an oven at 80 ° C. × 50% RH for 4 days. Thereafter, the sample film is cut into a size of 50 mm × 300 mm, and the peel force after standing for 1 hour at room temperature is 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.

<Adhesive composition>
Main agent: AT352 (manufactured by Seiden Chemical) 100 parts Curing agent: AL (manufactured by Seiden Chemical) 0.25 part Additive: X-301-375SK (manufactured by Seiden Chemical) 0.25 part Additive: X-301-352S (Siden) 0.4 parts toluene 40 parts

  Using the peel force values (F1, F2) obtained above, the change amount (ΔF) of the peel force was determined, and then the determination was made according to the following criteria.

ΔF (%) = (F2−F1)
<Criteria>
○: ΔF is 20 mN / cm or less (practical level)
X: ΔF exceeds 30 mN / cm (practical level)

(7) Initial evaluation of coating film adhesion of release film (practical property substitution evaluation)
The release surface of the sample film immediately after coating was rubbed 5 times with a tentacle, 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)

(8) Evaluation of coating film adhesion promotion of release film (practical property substitution evaluation)
The sample film was left in a constant temperature and humidity chamber at 80 ° C. and 90% RH for 2 weeks, and then the sample film was taken out. Thereafter, the release surface of the sample film was rubbed 100 times with absorbent cotton soaked with MEK (methyl ethyl ketone) and then rubbed 5 times with a tentacle, and the degree of removal 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)

(9) Measurement of surface specific resistance (R) of release film In the sample film, the surface specific resistance (R) of the film surface provided with the release layer was measured and judged according to the following criteria. The measurement conditions were 23 ° C. and 50% RH atmosphere.
Yokogawa Hewlett-Packard's inner electrode 50mm diameter, outer electrode 70mm diameter concentric circular electrode 16008A (trade name) was placed on the sample in an atmosphere of 23 ° C, 50% RH, and a voltage of 100V was applied, The surface resistivity of the sample was measured with 4329A (trade name), a company's high resistance meter.
<Criteria>
A: R (Ω) is 10 ¹⁰ or less (practical level, particularly good)
○: R (Ω) is 10 ¹² or less (practical level)
X: R (Ω) exceeds 10 ¹² (practical level)

(10) Comprehensive evaluation Using the release films produced in the examples and comparative examples, hydrogen (H ₂ ) gas generation amount, peel force (F), peel force change amount (ΔF) evaluation, release film coating film A comprehensive evaluation was performed according to the following criteria for each of the evaluation items of initial adhesion evaluation, evaluation of promotion of film adhesion of the release film, and surface resistivity (R).
(Criteria)
○: Hydrogen (H ₂ ) gas generation amount, peel force (F), peel force change amount (ΔF) evaluation, initial evaluation of release film coating film adhesion evaluation, release film adhesion promotion evaluation, surface specific All of the resistance (R) is ○ (a level that causes no problem in practical use)
Δ: Hydrogen (H ₂ ) gas generation amount, peel force (F), peel force change amount (ΔF) evaluation, initial evaluation of release film coating film adhesion evaluation, release film adhesion promotion evaluation, surface specific At least one of the resistances (R) is Δ (a level that may cause a problem in practical use)
×: Hydrogen (H ₂ ) gas generation amount, peel force (F), peel force change amount (ΔF) evaluation, initial evaluation of release film coating film adhesion evaluation, release film adhesion promotion evaluation, surface specific At least one of the resistances (R) is x (practically problematic level)

The polyester used in the examples and comparative examples was prepared as follows.
<Manufacture of polyester>
Production Example 1 (Polyethylene terephthalate A1)
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 atmospheric pressure to obtain polyethylene terephthalate A1 having an intrinsic viscosity of 0.61.

Example 1:
The polyethylene terephthalate A1 produced in Production Example 1 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., led to a tenter, and sequentially biaxially stretched 4.3 times in the TD direction. Thereafter, it was heat-fixed at 230 ° C. for 3 seconds to obtain a PET film having a thickness of 38 μm. Next, the following coating agent was applied by a reverse gravure coating method so that the coating amount (after drying) was 0.05 g / m ^2, and then heat-treated at 120 ° C. for 30 seconds.

Examples of compounds constituting the coating layer are as follows.
(Example compounds)
・ Organic compound containing zirconium element: (A1)
Partial hydrolyzate of zirconium tetraacetylacetonate / alkoxysilane compound: (A2)
Colcoat N-103X (manufactured by Colcoat)

<< Coating composition >>
Organic compound having zirconium element (A1): 1% by weight
Partially hydrolyzed alkoxysilane compound (A2): 99% by weight
The coating agent was diluted with methyl ethyl ketone (MEK) to make the solid content concentration 2% by weight.

Thereafter, a release agent having the following release agent composition was coated on the coating layer by a reverse gravure coating method so that the coating amount (after drying) was 0.1 g / m ² and heat-treated at 150 ° C. for 30 seconds. A release film was obtained later.
<< Releasing Agent Composition >> Compound Example Curable Silicone Resin (a1): (X-62-5039: manufactured by Shin-Etsu Chemical Co., Ltd.)
Curable silicone resin (a2): (KS-847H: manufactured by Shin-Etsu Chemical Co., Ltd.)
Peel control agent (b1): (KS-3800: manufactured by Shin-Etsu Chemical Co., Ltd.)
Peeling control agent (b2): (SD7292: manufactured by Toray Dow Corning)
Peeling control agent (b3): (BY24-4980: manufactured by Toray Dow Corning)
Curing agent (c1) (PL-5000: manufactured by Shin-Etsu Chemical Co., Ltd.)
Curing agent (c2) (PL-50T: manufactured by Shin-Etsu Chemical Co., Ltd.)

(Mixing conditions)
a1: 75% by weight
a2: 0% by weight
b1: 0% by weight
b2: 0% by weight
b3: 20% by weight
c1: 5% by weight
c2: 0% by weight
The release agent was diluted with a MEK / toluene mixed solvent (mixing ratio was 1: 1) to prepare a coating solution having a concentration of 2% by weight.

Examples 2-6 and Comparative Examples 1-8
In Example 1, the coating agent composition was changed to the coating agent composition shown in Table 2 below, and the release agent composition was manufactured in the same manner as in Example 1 except that the release agent composition was changed to the release agent composition shown in Table 2 below. A release film was obtained.

  Tables 3 and 4 show the characteristics of the release films obtained in the above Examples and Comparative Examples.

  The release film of the present invention can be suitably used for protecting various pressure-sensitive adhesive layers in addition to optical applications such as LCD, PDP, organic EL, and display member production.

Claims (1)

A release film in which a coating layer and a release layer are sequentially provided on one side of a polyester film stretched at least in a uniaxial direction, the coating layer containing an organic compound containing zirconium and an organosilicon compound, The surface specific resistance (R) of the layer surface is 10 ¹² or less, the peeling force between the acrylic adhesive tape and the release layer is 30 to 60 mN / cm, and the release film (40 cm ² ) in the 20 ml vial bottle A release film for protecting a pressure-sensitive adhesive layer, wherein the amount of hydrogen gas generated after immersion in a butanol solution containing 5% by weight of potassium hydroxide and heat-treated at 50 ° C. for 1 hour is 40 ppm or less.