KR20140001885A - Mold release film - Google Patents

Abstract

When using a double-sided adhesive sheet having no base material in optical applications such as a touch panel, a liquid crystal deflection plate, a retardation plate, etc., it is possible to minimize the peeling rate dependency and solve problems such as productivity and cost, Moreover, providing a release film of low cost which aimed at reducing process contamination and the foreign material to an adhesive by providing prevention property and testability to an oligomer is provided. It is a release film which consists of a polyester film containing a release layer, and is used by bonding a release layer to the adhesion layer of the double-sided adhesive sheet which does not have a base material, and a release layer has a silicone resin (a) and an alkyl group which have an alkenyl group as a functional group. It is a silicone mold release layer containing the silicone resin (b) which has, the transition component (c) to an adhesion layer, and a platinum catalyst (d), and content of a transition component (c) is 5-20 weight%, The release film whose low speed peeling force in a 300 mm / min speed range is 10-20 mN / cm, and whose high speed peeling force in a 10000 mm / min speed range is 2.5 times or less of a low speed peeling force.

Description

Release film {Mold release film}

The present invention relates to a release film, and more particularly, to a release film used for a double-sided pressure-sensitive adhesive sheet that does not have a substrate suitable for optical use.

Background Art Conventionally, various types of adhesive sheets for surface bonding between objects are known, and a double-sided adhesive sheet having no substrate as one of the adhesive sheets is known. The double-sided pressure-sensitive adhesive sheet having no base material is composed of a light-peeling sheet having a relatively low peeling force on both sides of the pressure-sensitive adhesive layer and a heavy-weight recycled sheet having a relatively high peeling force. After removing the peeling sheet on both sides, Sensitive adhesive sheet comprising only a pressure-sensitive adhesive layer having no substrate. In the double-sided pressure-sensitive adhesive sheet having no substrate, the light-exfoliation sheet is first peeled off, one side of the exposed pressure-sensitive adhesive layer is bonded to the object surface, and after the bonding, The surfaces are bonded to different object surfaces, whereby the objects are surface bonded.

BACKGROUND ART In recent years, double-sided pressure-sensitive adhesive sheets that do not have a base material have been widely used, and are also used in various optical applications. For example, as a member of the LCD, the release film on the light side of the peeling force of the double-sided pressure-sensitive adhesive sheet having no substrate is peeled off, a polarizing plate is bonded to the surface, and a release film having a large peeling force is used on the opposite surface side have.

Although processing at a high-speed station is considered to some extent in production workability, it is a matter of course that a light peeling force is achieved in a light-weight releasing film. However, It is very difficult to simultaneously achieve the fact that the difference in peeling force between the two layers does not decrease (Patent Document 1). If the difference in peeling force between the intermediate release film and the releasing film is reduced, the films on both sides are peeled off at the same time in the peeling step, and the peeling force difference becomes small, so that there is a problem that the pressure- (Patent Document 2).

The control of the difference in the peeling force is very difficult and various selection and control of the silicon component is required (Patent Documents 1 and 2), and furthermore, it is considered that control of the hardness of the silicone coating film is also required.

In applications where the double-sided pressure-sensitive adhesive sheet having no base material is used on the outside of a flat panel or the like having a relatively small area of a touch panel or a monitor, when the product is used as a product, the eyes of a person are close to each other, Since there is a problem visually, the inspection may be strengthened. At this time, inspection may be performed while bonding the release film to the double-sided pressure-sensitive adhesive sheet having no substrate. In this case, it is natural that there are few foreign matters in the film, and in order to facilitate inspection, it is necessary to manage the optical axis of the film, that is, the orientation of molecules (Patent Document 3).

Moreover, the low molecular component called an oligomer which is a polyester film group may originate in one of the foreign materials mentioned above. If this oligomer can be prevented, it is possible to suppress the foreign matter at the time of production and to prevent contamination of the film and the preceding process. In this invention, an oligomer (OL) is defined as cyclic trimer in the low molecular weight substance which crystallizes after heat processing and precipitates on a film surface.

Patent Document 1: JP-A-2009-220496 Patent Document 2: JP-A-10-158519 Patent Document 3: JP-A-2003-231214

The present invention has been made in view of the above circumstances, and a problem to be solved is that when a double-sided adhesive sheet having no substrate is used in optical applications, for example, a touch panel, a liquid crystal deflection plate, a retardation plate, or the like, the dependency of peeling rate is minimized. It is possible to provide a low-cost release film that enables suppression, solves problems such as productivity and cost, and provides an oligomer with preventing and inspecting properties, and aims to reduce foreign substances to process contamination and adhesives. Is in.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in view of the said situation, according to the polyester film which has a release layer of a specific structure, it discovered that the said subject could be easily solved and came to complete this invention.

That is, the summary of this invention consists of a polyester film containing a release layer, and is a release film used by bonding a release layer to the adhesion layer of the double-sided adhesive sheet which does not have a base material, and a release layer is an alkenyl group as a functional group. It contains the silicone resin (a) which has, the silicone resin (b) which has an alkyl group, the transition component (c) to a adhesion layer, and a platinum-type catalyst (d), and content of a transition component (c) is 5-20 weight% It is a silicone type release layer, and the low speed peeling force in the 300 mm / min speed range of a release layer is 10-20 mN / cm, and the high speed peeling force in a 10000 mm / min speed range is 2.5 times or less of the low speed peeling force. Present in the release film.

And in the laminated constitution of the preferable aspect of this invention, it has a coating layer obtained by apply | coating the coating liquid containing polyvinyl alcohol between a polyester film and a silicone type release layer.

According to this invention, since the release film which is light peeling and small peel rate dependence can be provided, the industrial value is high.

Carrying out the invention  Form for

<Polyester film>

The polyester film as a base of the release film of the present invention is a film obtained by stretching a melt-extruded sheet from an extrusion die according to a so-called extrusion method.

The polyester constituting the above film refers to a polymer containing an ester group obtained by polycondensation from a dicarboxylic acid and a diol or from a hydroxycarboxylic acid.

Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, adipic acid, azelaic acid, sebacic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and the like. As the diol, ethylene glycol, 1,4 -Butanediol, diethylene glycol, triethylene glycol, neopentyl glycol, 1,4-cyclohexane dimethanol, polyethylene glycol, etc. can be illustrated, As a hydroxycarboxylic acid, p-hydroxy benzoic acid, 6-hydroxy-2 -Naphthoic acid, etc. can be illustrated. Representative examples of such polymers include polyethylene terephthalate and polyethylene-2,6-naphthalate.

In the film, particles are preferably blended for the main purpose of imparting releasability and preventing scratches in each process. The type of particles to be blended is not particularly limited as long as it is a particle capable of imparting lubricity, and specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, And the like. Heat resistant organic particles as described in Japanese Patent Publication No. 59-5216 and Japanese Patent Application Laid-Open No. 59-217755 may also be used. Examples of the heat-resistant organic particles include thermosetting urea resin, thermosetting phenol resin, thermosetting epoxy resin, and benzoguanamine resin. In the polyester production process, precipitated particles in which a part of metal compounds such as catalysts are precipitated and finely dispersed can be used.

On the other hand, the shape of the particles is not particularly limited, and any of a spherical shape, a massive shape, a rod shape, a flat shape, and the like may be used. The hardness, specific gravity, color, and the like are not particularly limited. These series of particles may be used in combination of two or more kinds, if necessary.

Moreover, the average particle diameter of particle | grains is 0.01-3 micrometers normally, Preferably it is 0.1-2 micrometers. When average particle diameter is less than 0.01 micrometer, this activity may not be fully provided. On the other hand, when it exceeds 3 micrometers, transparency may fall because of the aggregate of the particle at the time of film forming, and breakage etc. are easy to be caused, and it may become a problem in terms of productivity.

The content of the particles is usually in the range of 0.001 to 5% by weight, preferably 0.005 to 3% by weight. When the content of the particles is less than 0.001% by weight, the film may not be sufficiently lubricated. On the other hand, when the content is more than 5% by weight, transparency of the film may be insufficient.

The method of blending the particles in the film is not particularly limited, and conventionally known methods can be employed. For example, it may be added at any stage of producing the polyester, but it is preferably added after completion of the esterification or transesterification reaction.

Also, a method of blending a slurry of particles dispersed in ethylene glycol or water or the like with a polyester material by using a vented kneading extruder, or a method of blending a dry material with a polyester material by using a kneading extruder do.

In addition to the above-mentioned particles, conventionally known antioxidants, antistatic agents, heat stabilizers, lubricants, dyes, pigments and the like can be added to the film, if necessary.

Although the thickness of a polyester film will not be specifically limited if it is a range which can form into a film as a film, Usually, 10-350 micrometers, Preferably it is 38-125 micrometers, More preferably, it is the range of 50-100 micrometers. When film thickness is thinner than 10 micrometers, when the adhesive sheet is processed by this application, the external foreign material which arose at the process etc. is transferred to an adhesive, and when a release film is processed, coating property is bad and the productivity deteriorates. Can be mentioned. When the film thickness is large, a problem of cost is caused.

Production examples of the polyester film will be specifically described below, but the production examples are not limited to the following examples. That is, it is preferable to use a polyester raw material as described above to cool and solidify a molten sheet extruded from a die in a cooling roll to obtain an unstretched sheet. In this case, in order to improve the planarity of the sheet, it is preferable to enhance the adhesion between the sheet and the rotary cooling drum, and the electrostatic adhesion method and / or the liquid application adhesion method are preferably employed. Then, the obtained unstretched sheet is stretched in the biaxial direction. In this case, first, the unstretched sheet is stretched in one direction by a roll or tenter type stretching machine. The stretching temperature is usually 90 to 140 占 폚, preferably 95 to 120 占 폚, and the stretching magnification is usually 2.5 to 7 times, preferably 3.0 to 6 times. Then, the stretching is carried out in a direction orthogonal to the stretching direction of the first stretch. In this case, the stretching temperature is usually 90 to 170 占 폚, and the stretch ratio is usually 3.0 to 7 times, preferably 3.5 to 6 times. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C under relaxation or within 30% of relaxation to obtain a biaxially oriented film. In the above stretching, a method of performing unidirectional stretching in two or more stages can be employed. In this case, it is preferable that the stretching magnifications in the two directions finally fall within the above ranges.

In the production of a polyester film, a simultaneous biaxial stretching method can be employed. The simultaneous biaxial stretching method is a method in which the above-mentioned unstretched sheet is simultaneously stretched in the machine direction and the width direction under the temperature-controlled state at 90 to 140 캜, preferably 80 to 110 캜, and oriented. The stretching magnification is, Preferably 4 to 50 times, more preferably 7 to 35 times, and still more preferably 10 to 25 times. Then, heat treatment is performed at a temperature of 170 to 250 DEG C under relaxation or within 30% to obtain a stretched oriented film. Conventionally known stretching methods such as a screw method, a pantograph method, and a linear driving method can be employed for the simultaneous axial stretching device employing the above-described stretching method.

&Lt; Coated layer obtained by applying a coating liquid containing polyvinyl alcohol >

The above-mentioned coating layer is provided not only for OL sealing but also for preventing process contamination by OL and contamination when bonding to a pressure-sensitive adhesive layer.

The content of polyvinyl alcohol in the coating layer is usually 10 to 100% by weight, preferably 20 to 90% by weight, and more preferably 30 to 90% by weight. If the content of polyvinyl alcohol is less than 10% by weight, the oligomer sealing effect is insufficient, which is not preferable.

The polyvinyl alcohol can be synthesized by a usual polymerization reaction, and is preferably water-soluble. The polymerization degree of polyvinyl alcohol is not particularly limited, but is usually 100 or more, preferably 300 to 40000. When the degree of polymerization is 100 or less, the water resistance of the coating layer tends to decrease. The saponification degree of the polyvinyl alcohol is not particularly limited, but is usually 70 mol% or more, preferably 80 mol% or more and 99.9 mol% or less.

If necessary, an aqueous solution other than the above-mentioned polyvinyl alcohol or a water-dispersible binder resin may be used in combination with the coating layer. The binder resin is a polymer compound having a number average molecular weight (Mn) of 1,000 or more as determined by gel permeation chromatography (GPC), in accordance with a polymer compound safety evaluation flow scheme (meeting of the Chemical Council, November 60, It can be defined as having a film formability. Examples of such a binder resin include a polyester, a polyurethane, an acrylic resin, a vinyl resin, an epoxy resin, an amide resin, and an acrylate resin. These skeleton structures may have a substantially complex structure by copolymerization or the like. Examples of the binder resin having a composite structure include acrylic resin graft polyesters, acrylic resin graft polyurethanes, vinyl resin graft polyesters, vinyl resin graft polyurethanes, and acrylate resin graft polyethylene glycols. The blending amount of the binder component is preferably 50 parts by weight or less, and more preferably 30 parts by weight or less, based on the weight of the coating layer.

The coating layer may contain a crosslinking reactive compound, if necessary. Examples of the crosslinking reactive compound include compounds such as methylol or alkylol urea compounds, melamine compounds, guanamine compounds, acrylamide compounds and polyamide compounds, polyamines, epoxy compounds, oxazoline compounds, aziridine compounds, block isocyanate compounds, A polyfunctional low molecular weight compound such as a silane coupling agent, a titanium coupling agent, a zircaluminate coupling agent, a metal chelate, an organic acid anhydride, an organic peroxide, a thermally or photoreactive vinyl compound or a photosensitive resin, and a polymer compound.

The crosslinking reactive compound is capable of improving the cohesiveness, surface hardness, frictional resistance, solvent resistance and water resistance of the coating layer by performing a crosslinking reaction with the functional group of the resin contained in the coating layer. For example, when the functional group of resin for adhesion is a hydroxyl group, as a crosslinkable compound, a melamine type compound, a block isocyanate compound, an organic acid anhydride, etc. are preferable, and when the functional group of polyester for adhesion is an organic acid and its anhydride, as a crosslinkable compound Epoxy-based compounds, melamine-based compounds, oxazoline-based compounds, metal chelates, and the like are preferable, and in the case where the functional group of the resin for adhesion is amines, the crosslinkable reactive compound is preferably an epoxy-based compound and the like, and the functional group contained in the resin It is preferable to select and use a thing with a high crosslinking reaction efficiency. Examples of the melamine compound include methoxymethylated melamine and butoxymethylated melamine, which are alkylol or alkoxyalkylated melamine compounds, and those obtained by co-condensing urea or the like with a part of melamine can also be used.

The crosslinking reactive compound may be either a low molecular weight compound or a polymer having a reactive functional group insofar as the reactive functional group necessarily contains two or more functional groups in one molecule. The blending amount of the crosslinking reactive compound is preferably 50 parts by weight or less, more preferably 30 parts by weight or less, particularly preferably 15 parts by weight or less, based on the weight of the coating layer.

When the binder resin and the crosslinking agent are blended at an arbitrary ratio, the coating layer densely forms the barrier layer, so that the OL can be more effectively suppressed. For this purpose, there is an effect that OL from the polyester film is not adhered to the maximal force, the pressure-sensitive adhesive, and does not come out in the previous processing step.

The coating layer may contain inert particles for the purpose of improving the sliding property of the coating layer, if necessary. Examples of the inert particles include inorganic inert particles and organic inert particles. Examples of the inorganic inert particles include silica sol, alumina sol, calcium carbonate, and titanium oxide. Examples of the organic inert particles include organic particles typified by crosslinked particles obtained by combining the particles with a polystyrene resin, a polyacrylic resin, a polyvinyl resin alone or a copolymer containing them, or a crosslinking component thereof. These inert particles preferably have a softening temperature or a decomposition temperature of about 200 캜 or higher, more preferably 250 캜 or higher, particularly 300 캜 or higher. The average particle diameter d of the inert particles is selected so as to satisfy the relationship of 1/3? D / L? 3 and 1/2? D / L? 2 when the average film thickness of the coating layer is .

The coating layer may contain a small amount of additives such as a surfactant, a defoaming agent, a coating improver, a thickener, a low molecular weight antistatic agent, an organic lubricant, an antioxidant, an ultraviolet absorber, a foaming agent, a dye and a pigment. These additives may be used alone or in combination of two or more thereof, if necessary. The coating layer may be formed on only one side of the polyester film or on both sides of the polyester film. In the case of forming only one surface, another type of coating layer may be formed on the opposite surface as necessary to give further different characteristics. The film before coating may be subjected to a chemical treatment or a discharge treatment in order to improve the coating property and adhesiveness of the coating liquid to the film.

The coating liquid used for forming the coating layer is preferably adjusted with water as a main medium in terms of stability and hygiene in general. In limiting water to a main medium, it may contain a small amount of an organic solvent for the purpose of improving dispersion in water or for improving film-forming performance. When the organic solvent is mixed with water as a main medium, it is preferable to use it in a range of dissolving in water. However, if it is a stable emulsion (emulsion) that can not be separated by long-term storage, it may be used in a state in which it is not dissolved in water . The organic solvent may be used alone or in combination of two or more thereof, if necessary.

As a method for applying the coating liquid to the surface of the polyester film, there can be used a reverse roll coater, a gravure coater, a rod coater, an air duct coater, etc. disclosed in "Coating Method" have.

The method of providing the coating layer is not particularly limited, but a method of applying the coating liquid (in-line coating) in the process of producing the polyester film is suitably employed. Specifically, there may be mentioned a method of applying a coating liquid on the surface of an unstretched sheet and drying, a method of applying a coating liquid on the uniaxially stretched film surface and drying, a method of applying a coating liquid on the surface of a biaxially stretched film and drying . Among them, a method of drying and curing the coating layer at the same time in the process of applying the coating liquid to the surface of the unstretched film or uniaxially stretched film and then performing the heat treatment on the film is economical. As a method of forming the coating layer, any of the above-mentioned coating methods may be used in combination if necessary. Specifically, a method in which a first layer is coated on a surface of an unstretched sheet, followed by drying, followed by stretching in a uniaxial direction, and then a second layer is applied and dried.

When a coating layer is provided by in-line coating, the above-described series of compounds is used as an aqueous solution or an aqueous dispersion, and a coating solution adjusted on the basis of a solid concentration of about 0.1 to 50% by weight is applied to the polyester film It is preferable to produce a laminated polyester film. A small amount of an organic solvent may be contained in the coating liquid for the purpose of improving the dispersibility into water, improving the film formability, and the like without departing from the gist of the present invention. The organic solvent may be only one type, or two or more types may be suitably used.

The drying and curing conditions at the time of forming the coating layer on the polyester film are not particularly limited. For example, in the case of providing the coating layer by in-line coating, it is usually 3 to 200 seconds at 70 to 280 ° C. It is good to perform heat processing on the basis of. If necessary, active energy ray irradiation such as heat treatment and ultraviolet ray irradiation may be used in combination. The polyester film may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

When the release film has a coating layer containing polyvinyl alcohol, the amount of OL extracted from the surface of the coating layer by dimethylformamide after the release film is subjected to heat treatment (180 ° C, 10 minutes) is 1.0 mg / m ² or less desirable. When the OL is more than 1.0 mg / m ² , there is a process contamination, a foreign matter is generated at the time of bonding the pressure-sensitive adhesive, and the yield of the product is decreased.

The film thickness of the coating layer is usually in the range of 0.002 to 1.0 g / m ² , preferably 0.005 to 0.5 g / m ² , more preferably 0.01 to 0.2 g / m ² . When the film thickness is less than 0.002 g / m ² , there is a possibility that sufficient adhesion can not be obtained. When it exceeds 1.0 g / m ² , there is a possibility that appearance, transparency and blocking property of the film deteriorate. The components in the coating layer can be analyzed by, for example, surface analysis such as TOF-SIMS.

In the present invention, the film may be a film having a structure in which a polyester having a low content of OL is coextruded and laminated on at least one surface of a layer made of a polyester having a normal OL content. When such a structure is used, It is particularly preferable to obtain an effect of preventing the spots caused by the precipitated OL in the film.

&Lt;

The releasing layer in the present invention is a releasing layer comprising a silicone resin (a) having an alkenyl group as a functional group, a silicone resin (b) having an alkyl group as a functional group, a transition component (c) Based release layer.

First, the curable silicone resin containing an alkenyl group is a diorganopolysiloxane having a molecular chain end trimethylsiloxane-blocked dimethylsiloxane-methylhexenylsiloxane copolymer (dimethylsiloxane unit: 96 mol%, methylhexenylsiloxane unit: 4 mol% (Dimethylsiloxane unit: 97 mol%, methylhexenylsiloxane unit: 3 mol%), dimethylhexenylsiloxane-blocked dimethylsiloxane-blocked dimethylsiloxane-blocked dimethylsiloxane-methylhexenylsiloxane copolymer Methylhexenylsiloxane copolymer (95 mol% of dimethylsiloxane unit and 5 mol% of methylhexenylsiloxane unit).

Subsequently, the curable silicone resin containing an alkyl group is preferably an organohydrogenpolysiloxane having a molecular chain end trimethylsiloxy group-blocked methylhydrogenpolysiloxane, a molecular chain endblocked trimethylsiloxy group-blocked dimethylsiloxane-methylhydrogen siloxane polymer, Methylhydrogenpolysiloxane blocked with dimethylhydrogensiloxy group at both ends of the chain, dimethylhydrodystyrene siloxane blocked at both ends of the molecular chain with dimethylhydroxysilane, and methylhydrogenpolysiloxane copolymer.

The release film of the present invention is used by bonding the release layer to an adhesive layer of a double-sided pressure-sensitive adhesive sheet having no substrate, but the silicone resin contains a transition component to the pressure-sensitive adhesive layer. Silicon oil is typically used as the transition component. The silicone oil is a silicone oil called a straight silicone oil or a modified silicone oil, and the following may be mentioned. Examples of the straight silicone include dimethyl silicone oil, methylphenyl silicone oil and methylhydrogen silicone oil. Examples of the modified silicone oil include side chain type polyether modification, aralkyl modification, fluoroalkyl modification, long chain alkyl modification, high fatty acid ester modification, high fatty acid amide modification, polyether long chain alkyl modification and aralkyl modification, Modified, polyether-modified polyether and methoxy-modified polyether, and the like. Straight silicone oil and modified silicone oil are both non-reactive, non-trivial oils.

The content of the transition component is 5 to 20% by weight, preferably 10 to 13% by weight, more preferably 0.1 to 5.0% by weight. When the content of the transition component is lower than 5%, the rate dependency to be described later increases, while when it exceeds 20% by weight, the curability is remarkably lowered and the adhesion is also deteriorated.

KS-777, KS-778, KS-779H, KS-847H, KS-856, and X-62-KS-776 manufactured by Shinetsu Kagaku Kogyo Co., 2422, X-62-2461; DKQ3-202, DKQ3-203, DKQ3-204, DKQ3-205, DKQ3-210 manufactured by Dow Corning Asia Co., Ltd.; YSR-3022, TPR-6700, TPR-6720, TPR-6721 manufactured by Toshiba Silicone Co., Ltd .; LTC300 ', LTC303E, LTC310, LTC314, SRX357, BY24-749, SD7333, BY24 manufactured by Toray Dow Corning -179, SP7015, SP7259, SD7220, SD7226, SD7229, etc. are mentioned. In addition, a release control agent may be used in combination to adjust the releasability of the release layer.

(B) a silicone resin having an alkyl group as a functional group, and (c) a transition component (c) to the pressure-sensitive adhesive layer, but the silicone resin having an alkenyl group as a functional group The ratio of the resin (a) and the silicone resin (b) having an alkyl group as a functional group, and (b) / (a) is usually 0.5 to 2 parts by weight. In the present invention, a silicone resin having an alkenyl group and an alkyl group as a functional group may be used.

As a method of providing the releasing layer to the polyester film, a conventionally known coating method can be used as in the case of the above-mentioned coating layer. The coating amount when forming the releasing layer is usually in the range of 0.01 to 1 g / m ² .

The surface on which the release layer is not provided may be provided with a coating layer such as an adhesive layer, an antistatic layer, an oligomer precipitation preventing layer, or the like, and the polyester film may be subjected to surface treatment such as corona treatment or plasma treatment.

In the present invention, in order to make the release layer clean and firm, a platinum-based catalyst for promoting the reaction of the addition type is used. Examples of the component include platinum compounds such as chloroplatinic acid, an alcohol solution of chloroplatinic acid, a complex of chloroplatinic acid with olefin, complex of chloroplatinic acid with alkenylsiloxane, platinum black, platinum supported silica, and platinum supported activated carbon. The platinum-group catalyst content in the release layer is usually in the range of 0.3 to 3.0 wt%, preferably 0.5 to 2.0 wt%. If the content of the platinum-based catalyst in the release layer is lower than 0.3% by weight, the problem of the peeling force and the curing reaction in the coating layer become insufficient, so that problems such as surface deterioration may occur. On the other hand, If the content of the catalyst is more than 3.0% by weight, the cost is high. In addition, there is a case where a process problem such as generation of gel foreign matters due to high reactivity occurs.

In addition, acetylenic alcohol may be added as the reaction inhibitor, because the reaction of the addition type is highly reactive. The component is an organic compound having a carbon-carbon triple bond and a hydroxyl group, but preferably 3-methyl-1-butyn-3-ol, 3,5-dimethyl- &Lt; / RTI &gt;

<Peel strength>

In the present invention, the peeling force means that a double-sided adhesive tape (Nito Denkou manufactured "No. 31B") is adhered to the release layer surface and left at room temperature for 1 hour, after which the base film and the peeling angle are 180 ° and optional. Refers to the value measured by the tensile tester when the tape is peeled off at a tensile rate of.

Although the method of adjusting peeling force in this invention can be achieved by selecting the composition in a mold release layer, other means can also be employ | adopted, and mainly the kind of mold release agent of a silicone mold release layer according to a desired peeling force. It is preferable to change, and since peeling force is largely dependent on the application amount of the release agent to be used, the method of adjusting the application amount of the release agent is more preferable.

In the present invention, Nitto Denko Co., Ltd. Residual adhesion rate with a 31B tape is 65%-90% normally, Preferably they are 70%-85%. When the residual adhesion rate is lower than 65%, the transferability is high, and when the pressure-sensitive adhesive is processed, the transition to roll contamination or the pressure-sensitive adhesive surface occurs, resulting in a decrease in adhesive peeling force. When the residual adhesion rate is 90% or more, the speed dependency cannot be suppressed small.

The peeling force value of the release film of this invention is the range of 10-20 mN / cm of low speed peeling force in 300 mm / min speed range. When the peeling force is less than 10 mN / cm, the peeling force is so light that the problem of peeling easily occurs even in a scene where it is not necessary to peel off originally. When the peeling force exceeds 20 mN / cm, the peeling force is heavy. There exists a problem that the difference in peeling force with a release film becomes small, a problem arises in a peeling process, and the selection width of the release film with a heavy peeling force may become narrow.

Moreover, in consideration of workability, the high speed peeling force in the speed range of 10000 mm / min is 2.5 times or less of the said low speed peeling force. When the ratio of the said peeling force is larger than 2.5 times, the peeling force difference with a release film with a heavy peeling force becomes small, and peeling does not become easy in a peeling process, or even an adhesive peels off.

Martens hardness of the release layer of the release film of this invention is 400 N / mm <^2> normally. Above, preferably, 450 N / mm ² Or more. Martens hardness of release layer is 400 N / mm ² When smaller, the peeling force of a release film WHEREIN: The peeling speed dependence may become large, and the film surface may be easy to be damaged, and OL may arise easily.

Said Martens hardness means hardness calculated | required by the instrumented indentation hardness test of the surface layer using the hardness measuring instrument which used the triangular indenter, and it is a 115 degree triangular indenter and a test force of 0.10 mN. Measured at

About the release film of this invention, a foreign material and optical interference color may generate | occur | produce by optical inspection of a process, etc. according to a use. In order to reduce the occurrence of foreign matter and optical interference in the optical inspection of the process, the optimization of the MOR＿C value measured by the microwave system molecular alignment system is very important. Means for satisfying the MOR'C value range of a polyester film exist in selecting extending | stretching conditions suitably with respect to a desired film thickness at the time of film forming.

MOR'C value of a polyester film is 1.5-3.0 normally, Preferably it is 1.8-2.7, More preferably, it is 2.1-2.4. If the MOR＿C value is greater than 3.0, the uniformity of the release layer may be lacking, and in the case of optical inspection, there may be a problem such that the optical interference color is easily seen. If the MOR＿C value is smaller than 1.5, there is a problem that the production yield of the release film itself becomes poor.

Example

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples unless it departs from the gist thereof. Moreover, the measuring method and evaluation method used by this invention are as follows.

(1) Measurement of Intrinsic Viscosity of Polyester:

1 g of polyester from which other polymer components and pigments which were incompatible were removed to polyester was weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) was added to dissolve and measured at 30 ° C.

(2) Measurement of average particle diameter (d50: μm):

The value of 50% of the integrated (weight basis) in the equivalent spherical distribution measured using the centrifugal sedimentation type particle size distribution analyzer (SA-CP3 type by Shimadzu Corporation) was made into the average particle diameter.

(3) Transmittance Measurement of Polyester Film:

In accordance with JIS-K7105, the total light transmittance of the polyester film was measured by the Nippon Denshoku Kogyo Co., Ltd. integrating sphere turbidimeter NDH-300A.

(4) Measurement of heat shrinkage rate of polyester film:

The polyester film is sampled at an arbitrary length L (cm) in the longitudinal direction (hereinafter abbreviated as MD) and the transverse direction (hereinafter abbreviated as TD), respectively. Subsequently, this sample is heated at 160 degreeC for 5 minutes in oven, the sample is removed from oven, and the length (cm) is measured. This operation is performed three times, and the average value is adopted as the heat shrinkage percentage value. The heating shrinkage ratio can be calculated by the following formula.

Heating Shrinkage (%) = ｛(L-ｌ) / L｝ × 100

(5) Determination of the amount of catalyst in the coating layer:

Using SAICAS, the sample film was obliquely cut to expose the cross section. Then, the catalyst amount containing platinum contained in the polyester film coating layer was calculated | required using TOF-SIMS (flight time mass spectrometry mass spectrum).

(6) Measurement of transition component amount:

To 15 g of the silicone resin diluted to 4% by weight of solid content in toluene, 0.04% by weight of platinum catalyst 0.04% was added, and after stirring, it was placed in a box made of a sheet made of Teflon (registered trademark) and thermosetted at 150 ° C. for 1 hour. (Sample 1). In the case of adding the transition component (corresponding to Comparative Example 2 described later), 30% by weight is added to the solid content of the silicone resin. Sample 1 is immersed in toluene per day, and the taken out sample is dried at 120 ° C for 30 minutes and allowed to cool to room temperature (sample 2). Subsequently, the component amount was computed by the following formula.

 Transfer component amount (% by weight) = (weight of sample 1-weight of sample 2) ÷ weight of sample 1 x 100

(7) Performance Evaluation of Release Film Adhesion Rate:

The sample film was cut out to A4, and a 75-micrometer-thick biaxially-stretched PET film (Mitsubishi Chemical Co., Ltd. product: Diamond F100-75) was superimposed on a release surface, and pressed for 2 hours under conditions of a temperature of 60 degreeC and a pressure of 1Mpa. do. The 75 micrometer-thick film pressed on this mold release surface is made into a transfer performance evaluation film. Similarly to an untreated PET film, a 75 micrometer-thick biaxially stretched PET film (same) is pressed, and it is set as a reference film. After sticking the adhesive tape (Nito Denko Co., Ltd. "No. 31B") to the surface where each film was pressed, it cuts into the size of 50 mm x 300 mm, and measures the peeling force after leaving at room temperature for 1 hour. It was. Peeling force was peeled 180 degree | times under the conditions of the tensile velocity of 0.3 (m / min) using "Ezgraph" made from Shimadzu Corporation.

Transferability Evaluation Adhesion Rate (%) = (Peeling Strength of Releasability Evaluation Film ÷ Peeling Force of Reference Film) × 100

In the film with large transferability, since much silicone adheres to the pressed film, the peeling force of an adhesive tape becomes small and a transferability evaluation adhesion rate (%) also falls.

(8) Evaluation of peeling force (F) of a release film:

After sticking the one side of the double-sided adhesive tape (Nito Denko "No. 31B") to the surface of the release layer of the sample film, it cut | disconnected to the size of 50 mm x 300 mm, and peeled after leaving for 1 hour at room temperature. Measure Peeling force was peeled 180 degree | times on the tensile speed of 300 mm / min and 10000 mm / min using the tensile tester (Intesco Model 2001 type | mold by Intesco Co., Ltd.). We judge based on the following criteria.

Peel force at 300 mm / min

(Circle): It is the range of 10-20 mN / cm.

×: less than 10 mN / cm or greater than 20 mN / cm

<Comparison of peel force at 10000 mm / min and peel force at 300 mm / min>

It determined by the value calculated | required by the following formula.

(10000 mm / min peel force (mN / cm)) ÷ (300 mm / min peel force (mN / cm))

(Circle): It is 2.5 or less.

×: greater than 2.5.

(9) Release characteristics:

The release property was evaluated from the situation when the release film was peeled off from the laminated film having the adhesive layer.

(Circle): A mold release film peels cleanly, and the phenomenon which an adhesive adheres to a mold release layer is not seen.

(Triangle | delta): Although a release film peels, an adhesive adheres to a release layer when it peels at high speed.

X: An adhesive adheres to a release film and does not peel easily.

(10) Hardness measurement of the coat surface of the polyester film:

About the surface layer of a polyester film, the triangular indenter (ridgeline angle 115 degrees, the Berkovich type), the test force: 0.10 mN, load support speed: using the dynamic ultra-micrometer altimeter (DUH-211) by the Misazu Corporation It measured on the conditions of 0.0060 mN / sec. And load support time: 2 sec., And Martens hardness was computed from the indentation depth with respect to the said test force. The frequency | count of a measurement is 12 times and these average values were taken.

(11) Measurement of OL extracted from anchor layer surface:

The release film of the heat treatment is heated in air at 180 캜 for 10 minutes in advance. Thereafter, the heat-treated film is brought into close contact with the inner surface of the box of 10 cm in length and 3 cm in height with the top open, to have a box shape. When providing an application layer, an application layer surface shall be inward. Subsequently, 4 ml of DMF (dimethylformamide) is placed in a box prepared by the above method and left for 3 minutes to recover DMF. The recovered DMF is supplied to liquid chromatography (Shimazu Corporation LC-7A), the amount of OL in the DMF is obtained, and the value is divided by the film area brought into contact with the DMF to make the film surface OL amount (mg / m ² ). .

The oligomer amount in DMF was calculated | required from the peak area ratio of a standard sample peak area and a measured sample peak area (absolute calibration curve method). The standard sample was prepared by accurately measuring OL (cyclic trimer), which had been aliquoted in advance, and dissolved in DMF accurately measured. The concentration of the standard sample is preferably in the range of 0.001 to 0.01 mg / ml. In addition, the conditions of the liquid chromatography were as follows.

Mobile phase A: acetonitrile

Mobile phase Ｂ: 2% acetic acid aqueous solution

Column: Mitsubishi Chemical Corporation, Inc.MCI GEL ODS 1HU

Column temperature: 40 ° C

Flow rate: 1 ml / min

Detection wavelength: 254 nm

(12) Measurement of MOR＿C value by microwave molecular alignment meter of polyester film:

The MOR_C value was calculated | required from the transmission microwave intensity pattern using the microwave type molecular orientation meter by Prince Instrument Co., Ltd. product.

(13) Measurement of MOR＿C value by microwave molecular alignment meter of polyester film:

The MOR_C value was calculated | required from the transmission microwave intensity pattern using the microwave type molecular orientation meter by Prince Instrument Co., Ltd. product. We judge based on the following criteria.

(Circle): It is the range of 2.0-2.5.

(Triangle | delta): It is the range of 1.5-1.9 or 2.6-3.0.

X: lower than 1.5% or higher than 3.0.

(14) practical characteristics:

<Visual inspection under reflected light>

Taking the polarizing plate inspection into consideration, the release film was applied through the pressure-sensitive adhesive so that the width direction of the release film obtained by applying a release agent on the film to a dryer temperature of 120 ° C. and a line speed of 30 m / min was parallel to the alignment axis of the polarizing film. To the polarizing film to make a polarizing plate, the polarizing plate was visually observed under fluorescent lamp reflection, and visual inspection under the reflected light was evaluated according to the following criteria. At the time of measurement, the sample of A4 size was cut | disconnected and implemented.

"Criteria"

(Circle): Inspection property is favorable.

(Triangle | delta): The inspection can be performed almost without a problem.

X: Poor testability.

(Circle) and (triangle | delta) are the levels which are satisfactory practically.

 <Visual inspection under cross nicol>

Taking the polarizing plate inspection into consideration, the release film was applied through the pressure-sensitive adhesive so that the width direction of the release film obtained by applying a release agent on the film to a dryer temperature of 120 ° C. and a line speed of 30 m / min was parallel to the alignment axis of the polarizing film. To the polarizing film to make a polarizing plate. Here, when preparing the said polarizing plate, the black metal powder (foreign substance) which has a size of 50 micrometers or more was mixed between an adhesive and a polarizing film so that it might become 50 pieces / m <^2> . The polarizing plate for inspection is superimposed on the polarizing plate mold release film which mixed the foreign material obtained in this way so that an orientation axis may be orthogonal to a release film width direction, irradiate white light from the polarizing plate side, and visually observe from the polarizing plate for inspection, and cross It evaluated according to the following criteria whether the foreign material mixed between an adhesive and a polarizing film can be found under Nicole. At the time of a measurement, the sample of A4 size was cut | disconnected and implemented from three places of the center part and both ends with respect to the width direction of the obtained film, respectively.

"Criteria"

(Circle): Foreign object recognition is favorable.

(Triangle | delta): A foreign material can be recognized without a comparative problem.

X: Foreign object recognition is bad.

(Circle) and (triangle | delta) are the levels which are satisfactory practically.

Among the said determination criteria, it is a level which can be used without problems practically more than (circle).

(15) comprehensive evaluation:

Evaluation taking into account all of the film forming properties, productivity, inspection characteristics, and the like is performed. We judge based on the following criteria.

(Circle): Even if it produces, it can fully supply as a product.

(Triangle | delta): Productivity is good and there is little frequency of problems in optical inspection.

X: The productivity is bad. Problems in optical inspection often occur.

The polyester used in Examples and Comparative Examples was prepared as follows.

<Method for producing polyester (a)>

100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol were used as starting materials, tetrabutoxy titanate was added to the reactor as a catalyst, the reaction starting temperature was set to 150 ° C, and the reaction temperature was gradually increased with distillation of methanol. After 3 hours, the temperature was 230 ° C. After 4 hours, after substantially transesterification, the polycondensation reaction was carried out for 4 hours.

That is, the temperature was gradually raised from 230 占 폚 to 280 占 폚. On the other hand, the pressure was gradually decreased from the atmospheric pressure to finally be 0.3 mmHg. After the start of the reaction, the reaction was stopped at the point corresponding to the intrinsic viscosity of 0.61 by the change in the stirring power of the reaction tank, and the polymer was discharged under nitrogen pressure to obtain a polyester (a) having the intrinsic viscosity of 0.61.

<Method for producing polyester (b)>

In the method for producing the polyester (a), after adding ethyl acid phosphate, an ethylene glycol slurry of synthetic calcium carbonate particles having an average particle diameter of 0.8 μm was added so that the content of the polyester was 1% by weight. Polyester (b) was obtained using the method similar to the manufacturing method of polyester (a). Obtained polyester (b) was intrinsic viscosity 0.60.

&Lt; Preparation of polyester (c) >

100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol were used as starting materials. Magnesium acetate tetrahydrate was added as a catalyst to the reactor. It was set to 230 degreeC after time.

After 4 hours, the transesterification reaction was substantially terminated. Ethyl phosphate was added to the reaction mixture, which was then transferred to a polycondensation tank. 0.04 parts of antimony trioxide was added thereto, followed by a polycondensation reaction for 4 hours. That is, the temperature was gradually raised from 230 deg. C to 280 deg.

On the other hand, the pressure was gradually decreased from the atmospheric pressure to finally be 0.3 mmHg. After the start of the reaction, the reaction was stopped at a point corresponding to the intrinsic viscosity of 0.45 due to the change in the stirring power of the reaction tank, and the polymer was discharged under nitrogen pressure to obtain a chip (c) of polyester. The intrinsic viscosity of this polyester was 0.45.

&Lt; Production of polyester (d) >

Intrinsic viscosity was raised for this polyester chip by the solid-phase polycondensation method. After 0.5 hour treatment in a preliminary crystallization tank under a nitrogen atmosphere at 170 ° C., the resultant was dried at 200 ° C. under a temperature of 200 ° C. using a tower dryer flowing in an inert gas. Then, it sent to the solid-state polymerization tank, solid-state polymerization was performed at 240 degreeC for 3 hours, and the polyester (d) of intrinsic viscosity 0.70 was obtained.

&Lt; Production of polyester (e) >

In producing the polyester (d), solid phase polymerization was carried out in a solid-phase polymerization vessel for 5 hours to obtain a polyester (e) having an intrinsic viscosity of 0.80.

Example  One

(Production of Polyester Film)

70 weight% of polyester (e) and 30 weight% of polyester (b) are mixed as a raw material of a surface layer, 84 weight% of polyester (a) and 16 weight% of polyester (b) are mixed as a raw material of an intermediate | middle layer, Each of them was fed to two vented extruders, melt-extruded at 290 ° C, and then cooled and solidified on a cooling roll having a surface temperature of 40 ° C using an electrostatically applied adhesion method to obtain an unstretched sheet. Subsequently, after extending | stretching 2.8 times longitudinally at 100 degreeC, after carrying out a preheating process in a tenter and performing lateral stretch of 5.1 times at 120 degreeC, heat processing is performed at 220 degreeC for 10 second, and then width direction at 180 degreeC after that 4% of relaxation was added, and the master roll of width 4000mm was obtained. Slitting was performed from the position of 1400 mm from the edge part of this master roll, it wound up to 1000 m in the core, and the polyester film was obtained. The total thickness of the obtained film was 50 micrometers (layer structure: 2.5 micrometers of surface layers / 45 micrometers of intermediate | middle layers / 2.5 micrometers of surface layers).

To the obtained polyester film, the mold release agent which consists of mold release agent composition-A shown below is apply | coated by the reverse gravure coat system so that application amount (after drying) may be set to 0.12 g / m <^2> , and the dryer temperature is 120 degreeC, and the line speed of 30 m / min. On the conditions, a rolled release polyester film was obtained. In the obtained release polyester film, the peeling force in the 300 mm / min speed range was 14 mN / cm, and the peeling force in the 10000 mm / min speed range was 32 mN / cm.

<Releasing agent composition -A>

20 parts of curable silicone resin (LTC303E: manufactured by Toray Dow Corning)

0.2 part of addition type platinum catalyst (SRX212: Toray Dow Corning)

MEK / toluene / n-heptane mixed solvent (mixing ratio 1: 1: 1)

Amount of transition component of mold release agent composition-A: 15 weight%

The obtained polyester film created the polarizing plate by the following method, and evaluated the optical characteristic and the peeling characteristic. The obtained release film had the favorable inspection property by reflection, the foreign material recognition property was favorable, and the polarizing plate peeled off cleanly, and the phenomenon which an adhesive adheres to a release layer was not seen.

<Production of Polarizing Plate with Release Film>

After apply | coating the acrylic adhesive shown below to a polarizing plate so that the thickness after drying may be set to 25 micrometers, and letting an inside pass through a 130 degreeC drying furnace for 30 second, a release film is bonded and the release film and a polarizing film were closely contacted through the adhesive. The polarizing plate with a release film was created. The bonding direction of the film was implemented so that the width direction of a release film might be parallel to the orientation axis of a polarizing film.

(Acrylic adhesive coating liquid)

100 parts of acrylic adhesive (Orivine BPS 429-4: Dongyang Ink Co., Ltd.)

Hardener (BPS 8515: Dongyang Ink Co., Ltd.) 3 parts

50 parts of MEK / toluene mixed solvent (mixing ratio 1: 1)

Example  2-4:

Example 1 WHEREIN: Except changing the application amount (after drying) of the coating layer containing polyvinyl alcohol, the silicone type release layer, and the amount of the shifting component of a mold release agent composition which change the draw ratio at the time of polyester film manufacture, and film thickness. And the same procedure as in Example 1 to obtain a polyester film. The obtained results are collectively shown in Table 1 below.

Comparative Example  One:

A polyester film was obtained in the same manner as in Example 1 except that the release agent composition was changed as follows. The obtained results are summarized in Table 2 below.

<Release agent composition-Ｂ>

Curable Silicone Resin (KS-847H: manufactured by Shin-Etsu Chemical Co., Ltd.)

Additional platinum catalyst (PL-50T: manufactured by Shin-Etsu Chemical) 가 0.2 part

MEK / toluene / n-heptane mixed solvent (mixing ratio 1: 1: 1)

Transfer component amount of mold release agent composition-B: 5 weight%

Comparative Example  2:

Except changing a mold release agent composition as follows, it manufactured similarly to Example 1, and obtained the polyester film. The obtained results are summarized in Table 2 below.

<Release Agent Composition-C>

20 parts of curable silicone resin (LTC303E: manufactured by Toray Dow Corning)

Silicone Oil (KS-64-100cs) 0.18part

Additive platinum catalyst (SRX212: manufactured by Toray Dow Corning) 0.2 part

MEK / toluene / n-heptane mixed solvent (mixing ratio 1: 1: 1)

Amount of transition component of mold release agent composition-C: 23 weight%

Comparative Example  3:

In Example 1, except having changed the application amount into 0.25 g / m < ² > in <release agent composition-A>, it manufactured like Example 1 and obtained the polyester film. The obtained results are collectively shown in Table 2 below.

Comparative Example  4:

In the comparative example 1, it manufactured similarly to the comparative example 1 except having changed the application amount into 0.08 g / m < ² > in <release agent composition-C>, and obtained the polyester film. The obtained results are collectively shown in Table 2 below.

Comparative Example  5-9:

In Example 1, it manufactured similarly to Example 1 except changing the application amount (after drying) of the coating layer containing polyvinyl alcohol, and the silicone type release layer which change the film thickness at the time of polyester film manufacture, , Polyester film was obtained. The obtained results are collectively shown in Table 3 below.

Comparative Example  10:

In Example 1, it manufactured similarly to Example 2 except having apply | coated the thing which added 3 parts of silicone oil (AL-1) to mold release agent composition-A, and obtained the polyester film. The obtained results are collectively shown in Table 3 below.

Claims (5)

It is a release film which consists of a polyester film containing a release layer, and is used by bonding a release layer to the adhesion layer of the double-sided adhesive sheet which does not have a base material, and a release layer has a silicone resin (a) and an alkyl group which have an alkenyl group as a functional group. It is a silicone mold release layer containing the silicone resin (b) which has, the transition component (c) to an adhesion layer, and a platinum catalyst (d), and content of a transition component (c) is 5-20 weight%, The release film characterized in that the low-speed peeling force in the 300 mm / minute speed range is in the range of 10 to 20 mN / cm, and the high-speed peeling force in the 10000 mm / minute speed range is 2.5 times or less of the low-speed peeling force. The release film of Claim 1 which has an application layer obtained by apply | coating the coating liquid containing polyvinyl alcohol between a polyester film and a silicone type release layer. The release film of Claim 1 or 2 in which the transition component in a silicone type release layer contains cyclic siloxane. The Martens hardness of any one of Claims 1-3 in a test force of 115 degree triangle indenter and 0.10 mN of a silicon type | mold release layer is 4,5 N / mm <^2>. Release film which is ideal. The release film of any one of Claims 1-4 whose MOR'C value of a polyester film is 1.5-3.0.