JP6229409B2 - Biaxially oriented polyester film for mold release - Google Patents

Description

The present invention relates to a biaxially oriented polyester film for mold release, and since it has low glossiness and high heat resistance on the mold release surface, it is particularly suitable as a heat resistant mold release film used for circuit process films that require matte tone. The present invention relates to a suitable biaxially oriented polyester film for release.

  In recent years, with the integration of circuits accompanying the expansion of smartphones and tablets, high precision and high density of printed wiring boards have been advanced. In the printed wiring board manufacturing process, a circuit is provided on the surface of an insulating substrate (polyimide resin, polyphenylene sulfide resin, etc.) and then covered with a cover lay, which is a heat-resistant resin film having an adhesive layer, for the purpose of insulation and circuit protection. Then, molding by press lamination is performed via a release film. At this time, the printed wiring board material, release property with the press plate, conformability to the shape, uniform formability, matte appearance, etc. are excellent. There is a need for release films. Further, there is an increasing need for a matte film excellent in appearance and releasability as a base material on which a functional layer such as an insulating layer or an electromagnetic wave shielding layer is transferred onto the surface of a circuit board by a hot press.

  A polyester film containing inorganic particles or organic particles at a high concentration has been proposed as a film to be applied to the application (for example, Patent Documents 1 and 2).

JP2013-56438A JP 2010-201858 A

  However, although the films described in Patent Documents 1 and 2 are excellent in matte tone, the heat resistance of the release surface is insufficient. It is difficult to maintain process stability in the manufacturing process.

  An object of the present invention is to eliminate the above-described problems of the prior art. That is, a biaxially oriented polyester film suitable for a heat-resistant release film used for circuit process films requiring a matte tone by having a matte appearance with a low glossiness and having a heat-resistant coating layer. Is to provide.

The gist of the present invention for solving this problem is as follows:
40 masses of melamine resin in the A layer of the base film having a polyester A layer containing 0.1 mass% or more and 10 mass% or less of inorganic particles and / or organic particles, with the entire polyester A layer being 100 mass%. A biaxially oriented polyester film for mold release, in which a coating layer containing not less than 90% and not more than 90% by mass is laminated, and the glossiness of the surface on which the coating layer is laminated is 30 or less,
It is.

The release biaxially oriented polyester film of the present invention has a low glossiness and a high heat resistance of the release surface, and therefore can be suitably used for a heat-resistant release film for circuit process films that require a matte tone. .

  The biaxially oriented polyester film for mold release of the present invention is a laminated film in which a coating layer having high heat resistance is laminated on a base film having at least one surface having a low glossiness.

  Examples of the resin constituting the base film used in the present invention include polyester, polyarylate, polyethylene, polypropylene, polyamide, polyimide, polymethylpentene, polyvinyl chloride, polystyrene, polymethyl methacrylate, polycarbonate, polyether ether ketone, and polysulfone. Polyethersulfone, fluororesin, polyetherimide, polyphenylene sulfide, polyurethane, and cyclic olefin resin can be used. In the present invention, the base film is preferably composed of a resin mainly composed of polyester from the viewpoint of heat resistance, strength, and productivity. In the present invention, “having polyester as a main component” means that 50% by mass or more of the resin constituting the base film is polyester. Among these, a biaxially oriented polyester film is most preferable in terms of heat resistance, strength, and productivity.

  The polyester used for the base film of the biaxially oriented polyester film for release according to the present invention is a general term for polymers having an ester bond as the main bond in the main chain, and is usually a dicarboxylic acid component and a glycol component. Can be obtained by polycondensation reaction.

  Examples of the dicarboxylic acid component used here include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenoxyethanedicarboxylic acid, and 5-sodiumsulfonedicarboxylic acid. Aromatic dicarboxylic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, 1,4-cyclohexanedicarboxylic acid and other alicyclic dicarboxylic acids, paraoxybenzoic acid Each component such as oxycarboxylic acid can be exemplified. Further, as dicarboxylic acid ester derivative components, esterified products of the above dicarboxylic acid compounds, such as dimethyl terephthalate, diethyl terephthalate, 2-hydroxyethyl methyl terephthalate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl isophthalate, adipic acid Examples of the components include dimethyl, diethyl maleate, and dimethyl dimer. In the polyester resin constituting the base film of the present invention, the ratio of terephthalic acid and / or naphthalenedicarboxylic acid in the total dicarboxylic acid component is preferably 95 mol% or more, more preferably 98 mol% or more. It is preferable from the viewpoint of heat resistance and productivity.

  Examples of the glycol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexane. Diol, aliphatic dihydroxy compounds such as 2,2-dimethyl-1,3-propanediol, diethylene glycol, polyethylene glycol, polypropylene glycol, polyoxyalkylene glycol such as polytetramethylene glycol, 1,4-cyclohexanedimethanol, spiroglycol Each component includes aromatic dihydroxy compounds such as alicyclic dihydroxy compounds such as bisphenol A and bisphenol S. Of these, ethylene glycol, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, and 1,4-cyclohexanedimethanol are preferably used in terms of moldability and handleability. In the polyester resin constituting the base film of the present invention, it is preferable from the viewpoint of heat resistance and productivity that the proportion of ethylene glycol in all diol components is 65 mol% or more.

  Two or more of these dicarboxylic acid components and glycol components may be used in combination.

From the viewpoint of moldability and dimensional stability, in the polyester resin constituting the base film, the proportion of terephthalic acid in the total dicarboxylic acid component in the polyester is 95 mol% or more, and the proportion of ethylene glycol in the total glycol component Is 65 to 95 mol%, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, and the total proportion of 1,4-cyclohexanedimethanol is preferably 5 to 35 mol%. More preferably, the total proportion of ethylene glycol is 75 to 95 mol%, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, and 1,4-cyclohexanedimethanol is 5 to 25. More preferably, the proportion of ethylene glycol is 80 to 95 mol%, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, 1,4-cyclohexanedimethanol 5 to 20 mol%.
The biaxially oriented polyester film for mold release according to the present invention contains 0.1% by mass of inorganic particles and / or organic particles with 100% by mass as a whole of the polyester A layer in order to reduce glossiness and achieve a matte appearance. It is necessary to have a polyester A layer that is contained in an amount of 10% by mass or less and disposed in at least one outermost layer of the base film.

  In addition, the inorganic particles and / or organic particles used in the present invention preferably have an average particle diameter of 2 μm or more and 10 μm or less from the viewpoint of suppressing the appearance of matte appearance and film tearing during peeling. It is more preferable if it is 4 μm or more and 8 μm or less. The average particle diameter in the present invention refers to the number average diameter D represented by D = ΣDi / N (Di: equivalent circle diameter of particles, N: number of particles).

  Here, the inorganic particles and / or organic particles to be used are not particularly limited. For example, the inorganic particles include wet and dry silica, colloidal silica, aluminum silicate, calcium carbonate, calcium phosphate, aluminum oxide, and the like. As the organic particles, particles containing styrene, silicone, acrylic acids, methacrylic acids, polyesters, divinyl compounds and the like as constituent components can be used. Among them, it is preferable to use inorganic particles such as wet and dry silica, colloidal silica, and aluminum silicate, and particles containing styrene, silicone, acrylic acid, methacrylic acid, polyester, divinylbenzene and the like as constituent components. From the viewpoint of mat appearance and economy, wet and dry silica, colloidal silica, and aluminum silicate are particularly preferably used. These externally added particles may be used in combination of two or more.

  In the present invention, the inorganic particles and organic particles used do not include coloring agents for coloring purposes such as dyes, inorganic pigments, and organic pigments. Specifically, Bengala, Molybdenum Red, Cadmium Red, Red Yellow Pb, Chromium Permillion, Blue Pigment, Bitumen, Cobalt Blue, Cerulean Blue, etc. Inorganic pigments such as yellow, yellow iron oxide, titanium yellow, manganese violet, mineral violet, titanium dioxide, barium sulfate, zinc white, zinc sulfate, carbon black, black iron oxide, condensed azo, phthalocyanine, quinacridone, dioxazine, isoindolinone Organic pigments such as quinophthalone and anthraquinone are not applicable to the inorganic particles and organic particles of the present invention.

  Further, the content of the inorganic particles and / or organic particles used in the biaxially oriented polyester film for release of the present invention is 0.1 mass with 100% by mass of the entire polyester A layer in order to achieve a matte appearance. % From 10% by mass to 10% by mass, but from the viewpoint of suppressing matte appearance and film breakage at the time of peeling, the entire polyester A layer is taken as 100% by mass and from 1.5% by mass to 8% by mass. It is preferable to contain, and it is preferable to contain 2 to 6 mass%.

The base film used for the release-oriented biaxially oriented polyester film of the present invention needs to be a biaxially oriented film from the viewpoint of heat resistance and dimensional stability. The biaxially oriented film is obtained by stretching an unstretched film in the longitudinal direction and then stretching in the width direction, or by stretching in the width direction and then stretching in the longitudinal direction, or by the longitudinal direction of the film. It can be obtained by stretching by a simultaneous biaxial stretching method in which the width direction is stretched almost simultaneously.
The stretching ratio of the biaxial stretching is preferably 3.0 to 4.2 times, more preferably 3.1 to 4.0 times, and further preferably 3 in the longitudinal direction and the width direction. .3 to 3.8 times. In this case, either of the stretching ratios in the longitudinal direction and the width direction may be increased or the same.

  The stretching speed is preferably 1,000% / min to 200,000% / min. More preferably, it is 1,500% / min to 50,000% / min, and more preferably 2,000% / min to 30,000% / min. By setting the stretching speed in the above range, the productivity is improved and the orientation can be easily controlled.

  In the case of the sequential biaxial stretching method in which stretching is performed in the width direction after stretching in the longitudinal direction, stretching is preferably performed under the following conditions because a difference in physical properties between the longitudinal direction and the width direction can be reduced. The stretching ratio is 3 to 4.2 times in the longitudinal direction, 3 to 4.2 times in the width direction, preferably 3.3 to 3.8 times in the longitudinal direction, and the width direction. The stretching ratio is 3.3 to 3.8 times, and the difference between the stretching ratios in the longitudinal direction and the width direction is 0.5 or less, more preferably 0.2 or less. In addition, the preheating temperature for stretching in the longitudinal direction (hereinafter sometimes referred to as longitudinal stretching) is preferably 80 to 100 ° C, more preferably 85 to 95 ° C. The longitudinal stretching temperature is preferably from 80 ° C. to 110 ° C., more preferably from 85 ° C. to 100 ° C., and most preferably from 85 ° C. to 95 ° C. The preheating temperature for the stretching in the width direction (hereinafter sometimes referred to as transverse stretching) is preferably 70 to 120 ° C, more preferably 75 to 110 ° C. The transverse stretching temperature is preferably 80 ° C. or higher and 165 ° C. or lower, more preferably 80 ° C. or higher and 150 ° C. or lower, and most preferably 80 ° C. or higher and 145 ° C. or lower. When the preheating temperature is equal to or higher than the above temperature range, thermal crystallization of the amorphous part in the film proceeds, and tearing may easily occur during stretching. Moreover, when preheating temperature is below the said temperature range, it becomes cold-temperature extending | stretching and thickness unevenness becomes large, and mechanical strength may deteriorate by the orientation degree of a film falling. When the stretching temperature exceeds the above range, process troubles such as roll adhesion and clip adhesion may occur. Moreover, when extending | stretching temperature is less than the said range, extending | stretching tension | tensile_strength raises rapidly, and a tear, clip peeling, etc. may arise, and productivity may fall significantly.

  The base film of the present invention is preferably obtained by performing a heat treatment after biaxially stretching an unstretched sheet. This heat treatment can be performed by any conventionally known method such as in an oven or on a heated roll. The heat treatment can be performed at an arbitrary temperature such that the temperature of the film is 120 ° C. or higher and 240 ° C. or lower, but is preferably 200 to 240 ° C. More preferably, it is 225 degreeC-240 degreeC. The heat treatment time can be any time, but preferably 1 to 60 seconds. More preferably, it is 1 to 30 seconds. The heat treatment may be performed while relaxing the film in the longitudinal direction and / or the width direction. Furthermore, re-stretching may be performed once or more in each direction, and then heat treatment may be performed.

  The base film of the present invention may be a single layer film or a laminated film having two or more layers. In the case of a three-layer structure, it is preferable that the compositions of both surface layers are the same from the viewpoint of productivity. Furthermore, in order to improve productivity, it is preferable to make the lamination | stacking thickness of both surface layers equal. When the base film of the present invention is a laminated film having two or more layers and the concentration of inorganic particles and / or organic particles of the polyester layer laminated on the outermost layer of the base film is different, the most inorganic particles and / or A layer having a high concentration of organic particles is defined as layer A as the outermost layer.

  The coating layer used in the present invention preferably contains a melamine resin as a main component from the viewpoint of increasing heat resistance and strength during hot pressing. Here, having melamine resin as the main component means that 40% by mass or more of the resin component of the release layer is melamine resin. By containing more than 40% by mass of the melamine resin, a crosslinking reaction with the binder resin and self-condensation of the melamine resin proceed during heating, and the heat resistance of the coating layer is greatly improved. When the concentration of the melamine resin is 40% by mass or less, the crosslinking reaction becomes insufficient, the heat resistance of the coating layer becomes insufficient, or the strength decreases, and the particles penetrate the coating layer during pressing and peel off. May be difficult. The concentration of the melamine resin is preferably 60% by mass or more and 90% by mass or less.

  Examples of the melamine resins include melamine formaldehyde resins, methylated melamine formaldehyde resins, butylated melamine formaldehyde resins, etherified melamine formaldehyde resins, melamine formaldehyde resins such as epoxy-modified melamine formaldehyde resins, urea melamine resins, and acrylic melamine resins. Melamine formaldehyde resin is preferable, and methylated melamine formaldehyde resin is particularly preferably used because it has an appropriate release property.

  When the coating layer used in the present invention contains a binder resin, the adhesiveness with the base film is improved, and the peeling force with the object to be peeled can be adjusted, or stretching at the time of molding in molding simultaneous transfer. This is preferable because the followability can be improved. Specific examples of the binder resin include polyester resins, acrylic resins, urethane resins, polyvinyls, polyalkylene glycols, polyalkyleneimines, celluloses, starches, etc., but stretch followability, release force at the time of release, and An acrylic resin is most preferably used from the viewpoint of peeling stability.

  Examples of the acrylic resin include a homopolymer or copolymer of (meth) acrylic acid alkyl ester, and a (meth) acrylic acid ester copolymer having a curable functional group at the side chain and / or main chain terminal. Examples of the functional group include a hydroxyl group, a carboxyl group, an epoxy group, and an amino group. Among them, an acrylic monomer copolymer obtained by copolymerizing an acrylic monomer and an acrylic ester having a curable functional group at the side chain and / or main chain terminal is preferable.

  Moreover, it is preferable that the coating layer used for this invention contains a mold release agent in the range which does not impair the target heat resistance and shaping | molding extension followable | trackability. When the release agent is uniformly dispersed on the surface of the coating film layer, the adhesiveness to the peeling layer to be laminated and peeled on the coating film layer and the peelability can be adjusted to an appropriate range. Examples of the mold release agent include fluorine compounds, long-chain alkyl compounds, and waxes. These release agents may be used alone or in combination.

  The fluorine compound is a compound containing a fluorine atom in the compound. Examples thereof include perfluoroalkyl group-containing compounds, polymers of fluorine-containing olefin compounds, and aromatic fluorine compounds such as fluorobenzene. When the release film of the present invention is used for molding simultaneous transfer foil applications and the like, a high heat load is applied at the time of transfer. Therefore, considering heat resistance and contamination, the fluorine compound is preferably a polymer compound.

  The long-chain alkyl compound is a compound having a linear or branched alkyl group having 6 or more, particularly preferably 8 or more carbon atoms. Specific examples include, but are not limited to, long-chain alkyl group-containing polyvinyl resins, long-chain alkyl group-containing acrylic resins, long-chain alkyl group-containing polyester resins, long-chain alkyl group-containing amine compounds, long-chain alkyl groups. And an ether compound, a long-chain alkyl group-containing quaternary ammonium salt, and the like. It is preferable that the long-chain alkyl compound is a polymer compound because the component derived from the coating layer on the surface of the counterpart base material bonded at the time of peeling can be suppressed.

  The wax is a wax selected from natural waxes, synthetic waxes, and blended waxes thereof. Natural waxes are plant waxes, animal waxes, mineral waxes, and petroleum waxes. Examples of plant waxes include candelilla wax, carnauba wax, rice wax, wood wax, and jojoba oil. Animal waxes include beeswax, lanolin, and whale wax. Examples of the mineral wax include montan wax, ozokerite, and ceresin. Examples of petroleum wax include paraffin wax, microcrystalline wax, and petrolatum. Synthetic waxes include synthetic hydrocarbons, modified waxes, hydrogenated waxes, fatty acids, acid amides, amines, imides, esters, and ketones. As synthetic hydrocarbons, Fischer-Tropsch wax (also known as Sazoir wax) and polyethylene wax are well known, but in addition to these, low molecular weight polymers (specifically, polymers having a viscosity average molecular weight of 500 to 20000) are used. The following polymers are also included. That is, there are polypropylene, ethylene / acrylic acid copolymer, polyethylene glycol, polypropylene glycol, polyethylene glycol and polypropylene glycol block or graft conjugate. Examples of the modified wax include montan wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives. The derivative herein is a compound obtained by any of purification, oxidation, esterification, saponification treatment, or a combination thereof. Hydrogenated waxes include hardened castor oil and hardened castor oil derivatives.

  By uniformly dispersing these release agents on the surface of the coating layer, the adhesion and peeling force with the coating layer to be laminated and peeled on the coating layer can be within an appropriate range. As the mold release agent, a long-chain alkyl compound is preferably used for the purpose of the present invention because the peel force can be adjusted over a wide range.

  Further, the resin constituting the coating layer used in the present invention may contain inert particles for the purpose of improving the adhesion and slipping property of the coating layer. Specific examples of the inert particles include silica, alumina, kaolin, calcium carbonate, titanium oxide, and organic particles.

  Furthermore, as long as it does not impair the gist of the present invention, an antifoaming agent, a coating property improver, a thickener, an organic lubricant, an antistatic agent, an antioxidant, an ultraviolet absorber, a foaming agent, a dye, etc. May be contained.

  In this invention, it is preferable to provide the resin composition containing a melamine compound (A) on the surface of A layer of a base film, and to heat after that and to form a coating film layer on a base film. In particular, it is preferable to set the heating temperature in the range of 200 ° C. or higher and 240 ° C. or lower so that the curing reaction of the coating layer further proceeds by using two or more steps having different temperatures. Thereby, a biaxially oriented polyester film for mold release having excellent heat release properties and mold release properties can be obtained.

  When providing the resin composition containing a melamine compound on a base film, a solvent may be used. That is, the melamine compound may be dissolved or dispersed in a solvent to form a coating solution, which may be applied to the base film. After coating, the solvent can be dried and heated to obtain a film having a coating layer laminated thereon. In the present invention, an aqueous solvent is preferably used as the solvent. By using an aqueous solvent, rapid evaporation of the solvent in the heating step can be suppressed, and a uniform coating layer can be formed, which is excellent in terms of environmental load.

  Here, the aqueous solvent is soluble in water such as water or water and alcohols such as methanol, ethanol, isopropyl alcohol and butanol, ketones such as acetone and methyl ethyl ketone, and glycols such as ethylene glycol, diethylene glycol and propylene glycol. A certain organic solvent is mixed at an arbitrary ratio.

  As a method for applying the resin composition to the base film, either an in-line coating method or an off-coating method can be used, but an in-line coating method is preferable. The in-line coating method is a method of applying in the process of manufacturing a polyester film. Specifically, it refers to a method of coating at any stage from melt extrusion of the resin constituting the base film to heat treatment after biaxial stretching, and usually obtained by rapid cooling after melt extrusion. A substantially amorphous unstretched (unoriented) film, a uniaxially stretched (uniaxially oriented) film stretched in the longitudinal direction, or a biaxially stretched (biaxially oriented before heat treatment) stretched further in the width direction. ) Apply to any film. In the coating by the off-coating method, the planarity may be remarkably lowered when heat treatment is performed under the above temperature conditions, and the film thickness control during the thin layer coating is difficult, so the process window is greatly increased. May be limited to

  In the present invention, the resin composition is applied to any of the unoriented film and the uniaxially oriented film before the crystal orientation is completed, the solvent is evaporated, and then the base film is uniaxially or biaxially. It is preferable to employ a method of stretching and heating to complete the crystal orientation of the base film and providing a coating layer. According to this method, since the film formation of the base film, the application of the resin composition, the drying of the solvent, and the heating (that is, the formation of the coating layer) can be performed at the same time, there is an advantage in manufacturing cost. . Moreover, it is easy to make the thickness of the coating layer thinner in order to perform stretching after coating.

  Among them, a method in which the resin composition is applied to a film uniaxially stretched in the longitudinal direction, the solvent is dried, and then stretched in the width direction and heated is preferable. Compared to the method of biaxial stretching after application to an unstretched film, the stretching process is less than once, so that the occurrence of defects and cracks in the coating layer due to stretching can be suppressed.

  On the other hand, the off-line coating method refers to a film-forming process on a film after stretching the unstretched film uniaxially or biaxially and performing a heat treatment to complete the crystal orientation of the base film, or an unstretched film. Is a method of applying the resin composition in a separate step. In this invention, it is preferable to provide by the in-line coating method from the various advantages mentioned above.

  Therefore, the best method for forming a coating layer in the present invention is to form a resin composition using an aqueous solvent by applying the resin composition on a base film using an in-line coating method, drying the aqueous solvent, and heating. It is a method to do.

  When preparing the coating liquid containing a resin composition, it is preferable to use an aqueous solvent as a solvent. The coating liquid containing the resin composition can be prepared by mixing and stirring a water-dispersed or water-soluble melamine compound and an aqueous solvent in any order at a desired weight ratio as necessary. Then, if necessary, various additives such as lubricants, inorganic particles, organic particles, surfactants, antioxidants, thermal initiators and the like are arbitrarily selected as long as the properties of the coating layer formed by the resin composition are not deteriorated. In this order, they can be mixed and stirred. The mixing and stirring methods can be performed by shaking the container by hand, using a magnetic stirrer or stirring blade, irradiating ultrasonic waves, vibrating and dispersing.

  As a method for applying the resin composition to the base film, any known method such as a bar coating method, a reverse coating method, a gravure coating method, a die coating method, or a blade coating method can be used.

  The coating layer used in the present invention preferably has a surface free energy of 25 mN / m or more and 40 mN / m or less. By setting the surface free energy to 25 mN / m or more and 40 mN / m or less, it is possible to achieve both appropriate adhesion in the pressing step and releasability at the time of peeling. More preferably, it is 30 mN / m or more and 38 mN / m or less, and most preferably it is 32 mN / m or more and 37 mN / m or less. The method for setting the surface free energy of the coating layer to 25 mN / m or more and 40 mN / m or less is not particularly limited. The method of doing is mentioned.

  The biaxially oriented polyester film for release according to the present invention has a glossiness of 30 or less on the surface where the coating layer is laminated on the polyester A layer in order to achieve excellent releasability and matte appearance. is necessary. By making the glossiness of the surface on which the coating film layer is laminated on the polyester A layer to be 30 or less, it is preferable because it is easy to achieve releasability and matte appearance as a circuit process film. When the glossiness is greater than 30, the mold release may be deteriorated and the matte tone may be insufficient. More preferably, the glossiness of the surface on which the coating layer is laminated on the polyester A layer is 25 or less, and most preferably 20 or less. Even when a functional layer such as an insulating layer or an electromagnetic wave shielding layer is transferred to a circuit board or the like by a heat press by setting the glossiness of the surface on which the coating layer is laminated to the polyester A layer to 20 or less The layer appearance is also very favorable because it provides an excellent matte appearance. The method of setting the glossiness of at least one side to 30 or less is not particularly limited. For example, inorganic particles and / or organic particles having a particle size of 2 μm or more and 10 μm or less are used in an amount of 1% by mass or more based on 100% by mass of the entire polyester A layer The method which has a polyester A layer containing 10 mass% or less is mentioned.

  The biaxially oriented polyester film for mold release of the present invention is an arbitrary one direction (X direction) of the film from the viewpoint of suppressing tearing at the time of film peeling when used as a heat-resistant release film as a process film for a circuit. The average value of tear propagation resistance in the direction orthogonal to the X direction (Y direction) is preferably 5 N / mm or more. When the average value of tear propagation resistance in any one direction (X direction) and the direction orthogonal to the X direction (Y direction) is less than 5 N / mm, when used as a heat-resistant release film, the film is torn during film peeling. There is a case. The average value of tear propagation resistance in any one direction (X direction) and the direction orthogonal to the X direction (Y direction) is more preferably 5.5 N / mm or more, and most preferably 6 N / mm or more. The higher the tear propagation resistance, the better from the viewpoint of suppressing film breakage, but from the viewpoint of film forming properties and practical properties, tear propagation in any one direction (X direction) and the direction orthogonal to the X direction (Y direction). The average value of resistance is more preferably 20 N / mm or less, and most preferably 10 N / mm or less.

  Especially as a method of setting the average value of tear propagation resistance in any one direction (X direction) of the biaxially oriented polyester film for mold release of the present invention and the direction orthogonal to the X direction (Y direction) to 5 N / mm or more. Although it is not limited, for example, inorganic particles and / or organic particles are contained more than inorganic particles and / or organic particles than a polyester A layer containing 0.1% by mass or more and 10% by mass or less, based on 100% by mass of the entire polyester A layer. The method of setting it as the structure which has a polyester B layer with little quantity is mentioned. When inorganic particles and / or organic particles are contained in the polyester film, the particles become the starting point and the tear propagation resistance is lowered, but the polyester B layer has a smaller content of inorganic particles and / or organic particles than the polyester A layer. In the polyester A layer, the glossiness can be lowered to 30 or less, and the tear propagation resistance can be kept high in the polyester B layer. In the present invention, the content of inorganic particles and / or organic particles in the polyester B layer having a smaller content of inorganic particles and / or organic particles than the polyester A layer is not particularly limited as long as it is lower than that of the polyester A layer. The amount is preferably less than 1% by mass, more preferably 0.5% by mass or less, and most preferably 0.1% by mass or less. For the purpose of increasing the average value of tear propagation resistance to 5 N / mm or more, the content of inorganic particles and / or organic particles in the polyester B layer is preferably 0% by mass.

  Moreover, since the biaxially oriented polyester film for mold release of the present invention needs to have a glossiness of 30 or less on the surface where the coating layer is laminated on the polyester A layer, the base film has a polyester B layer. In such a case, it is necessary that at least one surface layer of the A layer / B layer, A layer / B layer / A layer, or the like is the A layer.

  Moreover, as a method of setting the average value of tear propagation resistance in any one direction (X direction) of the biaxially oriented polyester film for mold release of the present invention and the direction orthogonal to the X direction (Y direction) to 5 N / mm or more. It is also preferable that the intrinsic viscosity (dl / g) of the polyester A layer is 0.6 or more. By making the intrinsic viscosity as high as 0.6 or more, it becomes possible to keep the tear propagation resistance high even if inorganic particles and / or organic particles are contained. The intrinsic viscosity of the polyester A layer is more preferably 0.62 or more, and most preferably 0.65 or more. In order to set the intrinsic viscosity of the polyester A layer to 0.6 or more, the intrinsic viscosity of the resin before the extrusion forming the polyester A layer is preferably 0.68 or more, more preferably 0.69 or more.

  In addition, the biaxially oriented polyester film for mold release of the present invention is obtained from the viewpoint of heat resistance when used for heat-resistant mold release applications, after heat-pressing for 2 hours at 180 ° C. × 3 MPa. It is preferable that the average value of tear propagation resistance in any one direction (X direction) and the direction orthogonal to the X direction (Y direction) is 5 N / mm or more. This is done by using a press machine heated to a temperature of 180 ° C. for both the upper mold temperature and the lower mold temperature, and a 0.2 mm thick aluminum plate / 0.125 mm thick polyimide film (Kapton 500H / V manufactured by Toray Du Pont ) / Biaxially oriented polyester film for mold release of the present invention / Polyimide film of 0.125 mm thickness (Kapton 500H / V manufactured by Toray DuPont) / Aluminum plate of 0.2 mm thickness 2 under the condition of 3 MPa It is a value obtained by taking out the biaxially oriented polyester film for release after heat-pressing after taking time-heating press and measuring the tear propagation resistance. When used in heat-resistant release applications, film peeling is generally performed after heating, and even if the tear propagation resistance before heating is high, the tear propagation resistance decreases after heating. In the film peeling process, the film may be torn. The average value of the tear propagation resistance in any one direction (X direction) and the direction orthogonal to the X direction (Y direction) after heat-pressing for 2 hours under the condition of 180 ° C. × 3 MPa is 5. 5 N / mm or more is more preferable, and 6 N / mm or more is most preferable. The average value of the tear propagation resistance in any one direction (X direction) and the direction orthogonal to the X direction (Y direction) after heating and pressing for 2 hours under the condition of 180 ° C. × 3 MPa is 5 N / mm. Although the method to make it above is not particularly limited, the average value of the tear propagation resistance in any one direction (X direction) and the direction perpendicular to the X direction (Y direction) of the film before pressing is 5 N / mm or more. In addition to the above method, a method in which the amount of carboxyl end groups of the polyester A layer is 20 eq / t or less is preferably used. By keeping the carboxyl end group amount of the polyester A layer as low as 20 eq / t or less, thermal decomposition of the polyester A layer during heating can be suppressed, and tear propagation resistance can be kept high even after heating. The method for setting the carboxyl end group amount of the A layer to 20 eq / t or less is not particularly limited, but the carboxyl end group amount of the resin constituting the polyester A layer is set to 20 eq / t or less, and further, the flow of nitrogen through the extruder during melt extrusion In the atmosphere, it is preferable to control the oxygen concentration to 0.7 volume% or less and the resin temperature to 265 ° C. to 285 ° C.

  Next, the method for forming a coating layer used in the present invention will be specifically described, but the present invention is not construed as being limited to such examples.

  When the base film is a laminated polyester film having a polyester A layer and a polyester B layer, first, as polyester A used for the polyester A layer, the average particle diameter of polyethylene terephthalate resin (a) and polyethylene terephthalate resin (a) A particle-containing polyethylene terephthalate resin (a ′) containing 5 μm silica particles is weighed at a predetermined ratio. Moreover, polyethylene terephthalate resin (a) is used as polyester B used for the polyester B layer.

  Then, the mixed polyester resin is supplied to a single screw extruder and melt extruded. At this time, the resin temperature is preferably controlled to 265 ° C to 295 ° C. Next, foreign matter is removed and the amount of extrusion is leveled through a filter and a gear pump, respectively, and discharged from the T die onto a cooling drum in a sheet form. At that time, an electrostatic application method in which a cooling drum and the resin are brought into close contact with each other by static electricity using an electrode applied with a high voltage, a casting method in which a water film is provided between the casting drum and the extruded polymer sheet, The sheet-like polymer is brought into close contact with the casting drum, cooled and solidified by a method of sticking the extruded polymer at a glass transition point to (glass transition point−20 ° C.) or a combination of these methods, and unstretched. Get a film. Among these casting methods, when using polyester, a method of applying an electrostatic force is preferably used from the viewpoint of productivity and flatness.

  This film is stretched 3 to 4.2 times in the longitudinal direction with a roll heated to 80 to 120 ° C. to obtain a uniaxially oriented PET film. A coating solution having a resin composition containing a melamine compound, prepared at a predetermined concentration, is applied to one side of the film. At this time, surface treatment such as corona discharge treatment may be performed on the coated surface of the PET film before coating. By performing surface treatment such as corona discharge treatment, the coating property of the resin composition on the PET film is improved, so that the wettability is improved, the repelling of the resin composition is prevented, and a uniform coating thickness is achieved. be able to.

  After coating, the edge of the PET film is held with a clip and guided to a preheating zone of 80 to 130 ° C., and the solvent of the coating solution is dried. After drying, the film is stretched 3 to 4.2 times in the width direction at a temperature of 100C to 160C. Subsequently, the first stage heat treatment is conducted for 1 to 30 seconds, and then the second stage heat treatment is performed at a temperature higher than the first stage heat treatment temperature and in the range of 200 to 240 ° C. Perform for ˜30 seconds to complete the crystal orientation and complete the formation of the coating layer. In this heating step (heat treatment step), 3 to 15% relaxation treatment may be performed in the width direction or the longitudinal direction as necessary.

  As a method for making the heat-resistant peelability and coating properties of the release biaxially oriented polyester film practically acceptable, it is preferable to form a coating layer under the following conditions.

After applying a coating liquid of a resin composition containing more than 40% by mass of a melamine resin to the entire resin composition constituting the coating layer on at least one side of the base film, the solvent is evaporated in a drying step. Then, in the method of forming a coating film layer in the heat treatment step, (i) to (iii) should be satisfied.
(I) The temperature of the heat treatment step is 200 to 240 ° C.
(Ii) The temperature difference between processes or between processes should be within 80 ° C. between the drying process and the heat treatment process.
(Iii) The thickness of the coating layer should be 0.02 μm or more and 0.5 μm or less.

  By performing the above heat treatment temperature at a high temperature of 200 ° C. or more and 240 ° C. or less, the self-condensation reaction between melamine resins or the crosslinking reaction between the melamine resin and the binder proceeds, and the heat resistance of the coating layer is improved. it can. Preferably it is 225 degreeC-240 degreeC. In addition, since the self-condensation reaction between melamine resins or the crosslinking reaction between melamine resin and binder resin proceeds, the follow-up property of the coating layer is improved. Accordingly, it is possible to suppress problems such as transfer of the coating layer and migration of particles.

  In the process of forming the coating film layer, the temperature difference between the processes or between the processes is within 80 ° C. between the drying process and the heat treatment process, so that the resin in the coating film layer can be relaxed and recycled. Dispersion occurs and the cross-linking reaction and self-condensation reaction proceed to a high degree, thereby forming a dense coating surface and increasing the heat resistance of the coating layer surface.

  In addition, when the thickness of the coating layer exceeds 0.5 μm, the mold followability at the time of pressing is lowered and cracks are likely to occur in the coating layer, so that the transfer of the coating layer and the transfer of particles may occur. is there. On the other hand, when the thickness of the coating layer is less than 0.02 μm, it is difficult to obtain a uniform coating layer, and heavy peeling may occur. The thickness of the coating layer is preferably 0.025 μm or more and 0.2 μm or less, and most preferably 0.03 μm or more and 0.1 μm or less. By satisfying the above process conditions (i) and (ii), it becomes possible to achieve sufficient heat resistance and releasability even in thin film coating of 0.1 μm or less. The thickness of the coating layer is measured by observing the cross section of the release-oriented biaxially oriented polyester film with a scanning electron microscope, transmission electron microscope, optical microscope or the like at a magnification of 500 to 10,000 times. be able to.

  An example of a method for producing a release biaxially oriented polyester film that satisfies the above three requirements simply and economically is an in-line coating method in which a coating layer is provided in the film production process. The inline coating method as used herein refers to a film obtained by dispersing a coating layer composition in water at least on a uniaxially stretched film, uniformly applied using a metalling bar, gravure roll, etc. This is a method of drying the coating agent. In this process, the heat treatment temperature of the film is set to 200 ° C. or more and 240 ° C. or less, and the maximum temperature of the drawing process, which is the previous process, is set to a temperature within 80 ° C. from the heat treatment temperature. The condition can be achieved. Moreover, thinning of a coating-film layer can be achieved by performing an extending | stretching process after coating-film layer composition application | coating. At this time, the heat treatment time is preferably 5 seconds or more and less than 25 seconds from the viewpoint of promoting the crosslinking reaction of the coating layer with the melamine resin. If the heat treatment time is less than 5 seconds, the crosslinking reaction of the coating layer does not proceed sufficiently, and the desired heat resistance is not exhibited. On the other hand, if the heat treatment time is longer than 25 seconds, thermal crystallization of the base film proceeds and becomes brittle, which may cause a handling problem such as notching during trimming. Specifically describing the temperature requirements in the above production, for example, by setting the transverse stretching temperature to 150 ° C. and the heat treatment temperature to 230 ° C., the temperature change between the steps is set to 80 ° C., and the heat treatment at a high temperature is realized. The

  The biaxially oriented polyester film for mold release according to the present invention has a film thickness of preferably 15 μm or more and 150 μm, more preferably 25 μm or more and 100 μm or less, and more preferably 30 μm or more, from the viewpoints of heat resistance, handleability and economy. Most preferably, it is 75 μm or less.

  Since the biaxially oriented polyester film for mold release of the present invention has low gloss and high tear propagation resistance, it can be suitably used as a heat-resistant release film as a circuit process film application requiring a matte tone. Moreover, since it is easy to control mold release property, it can use suitably as a protective film and a mold release film.

(1) Composition of polyester A polyester resin and a film are dissolved in hexafluoroisopropanol (HFIP), and the content of each monomer residue component and by-product diethylene glycol can be quantified using ¹ H-NMR and ¹³ C-NMR. it can. In the case of a laminated film, the components constituting each layer can be collected and evaluated by scraping off each layer of the film according to the laminated thickness. In addition, about the film of this invention, the composition was computed by calculation from the mixing ratio at the time of film manufacture.

(2) Intrinsic viscosity of polyester The intrinsic viscosity of the polyester resin and the film was measured at 25 ° C. using an Ostwald viscometer after dissolving the polyester in orthochlorophenol. In the case of a laminated film, the intrinsic viscosity of each layer can be evaluated by scraping each layer of the film according to the laminated thickness.

(3) Composition analysis of coating film layer The composition analysis of the coating film layer is performed on the surface of the release biaxially oriented polyester film by using an X-ray photoelectron spectrometer (ESCA), a Fourier infrared spectrophotometer (FT-IR). An ATR method and a time-of-flight secondary ion mass spectrometer (TOF-SIMS) were used. In addition, the coating layer is dissolved and extracted with a solvent and separated by chromatography, and then proton nuclear magnetic resonance spectroscopy (1H-NMR), carbon nuclear magnetic resonance spectroscopy (13C-NMR), Fourier infrared spectrophotometry. The structure was analyzed with a meter (FT-IR), and pyrolysis gas chromatography / mass spectrometry (GC-MS) was performed to analyze the composition of the coating layer.
By the above method, the identification of each constituent component in the coating layer and the quantitative determination of the composition ratio were performed.

(4) Film thickness, layer thickness The film was embedded in an epoxy resin, and the film cross section was cut out with a microtome. The cross section was observed with a transmission electron microscope (TEM H7100, manufactured by Hitachi, Ltd.) at a magnification of 5000 times, and the thickness of the film, the polyester layer, and the coating layer were determined.

(5) Average particle diameter of particles Polyester is removed from the polyester film by a plasma low-temperature ashing method (PR-503, manufactured by Yamato Kagaku) to expose the particles. This is observed with a transmission electron microscope (TEM H7100 manufactured by Hitachi, Ltd.) at a magnification of 2000 times, and the image of the particles (light density produced by the particles) is linked to an image analyzer (QTM900 manufactured by Cambridge Instrument). And the following numerical processing was performed with 5000 or more particles, and the number average diameter D determined thereby was defined as the average particle diameter.
D = ΣDi / N
Here, Di is the equivalent circle diameter of the particles, and N is the number of particles.

(6) Content of particles 1 g of the polymer was put into 200 ml of 1N-KOH methanol solution and heated to reflux to dissolve the polymer. 200 ml of water was added to the solution after dissolution, and the liquid was then centrifuged to settle the particles, and the supernatant was removed. Water was further added to the particles, and washing and centrifugation were repeated twice. The particles thus obtained were dried, and the content of the particles was calculated by measuring the mass of the particles.

(7) Glossiness According to the method specified in JIS-Z-8741 (1997), 60 ° mirror surface on both sides of film (I side / II side) using Suga Test Instruments' digital variable angle gloss meter UGV-5D The glossiness was measured for each surface at N = 3, and the average value was adopted for each.

(8) Using a tear propagation resistance load tear tester (manufactured by Toyo Seiki Co., Ltd.), it was measured according to JIS K-7128-2-1998. The sample has a rectangular shape with a length of 75 mm and a width of 63 mm in any one direction (X direction) of the film and a direction orthogonal to the X direction (Y direction). Read the indicated value when the remaining 43 mm is torn. The tear propagation resistance value was obtained by dividing the tear force (N) obtained from the indicated value by the film thickness (mm). The measurement was performed 10 times in each direction, and the average value was adopted.

(9) Tear propagation resistance after 2 hours of heating and pressing under conditions of 180 ° C. × 3 MPa Aluminum having a thickness of 0.2 mm using a press machine heated to a temperature of 180 ° C. for both the upper mold temperature and the lower mold temperature Plate / 0.125mm thick polyimide film (Toray DuPont Kapton 500H / V) / Releasable biaxially oriented polyester film / 0.125mm thick polyimide film (Toray DuPont Kapton 500H / V) / Thickness 0 A 2 mm aluminum plate was heated and pressed under a condition of 3 MPa for 2 hours. The biaxially oriented polyester film after hot pressing was taken out and the tear propagation resistance was measured in the same manner as (7).

(10) Amount of carboxyl end groups The polyester A layer was dissolved in cresol / chloroform (weight ratio 7/3) at 95 ° C., and the potential difference was measured with an alkali.

(11) Surface free energy Four types of water, ethylene glycol, formamide and diiodomethane are used as measurement solutions, and the surface of each liquid film using a contact angle meter (CA-D type manufactured by Kyowa Interface Science Co., Ltd.). The static contact angle with respect to was determined. Each liquid is measured five times, and the average contact angle (θ) and the surface tension component of the measurement liquid (j) are substituted into the following equations, respectively, and simultaneous equations consisting of four equations are expressed as γ ^L , γ ⁺ , Solved for γ ⁻ .
(Γ ^L γj ^L ) ^1/2 +2 (γ ⁺ γj ⁻ ) ^1/2 +2 (γj ⁺ γ ⁻ ) ^1/2
= (1 + cos θ) [γj ^L +2 (γj ⁺ γj ⁻ ) ^1/2 ] / 2
However, γ = γ ^L +2 (γ ⁺ γ ⁻ ) ^1/2
γj = γj ^L +2 (γj ⁺ γj ⁻ ) ^1/2
Here, γ, γ ^L , γ ⁺ and γ ⁻ are the surface free energy, long-range force term, Lewis acid parameter, and Lewis base parameter of the film surface, respectively, and γj, γj ^L , γj ⁺ , γj ^−. Indicates the surface free energy, long-range force term, Lewis acid parameter, and Lewis base parameter of the measurement solution used. The surface tension of each liquid used here was the value proposed by Oss (“fundamentals of Adhesion”, LH Lee (Ed.), P153, Plenum ess, New York (1991)).
The coating film layer of the measurement film was identified by observation of the film cross section shown in (4) and component analysis of the coating film layer shown in (3). The surface provided with the coating layer was specified by this method, and the surface free energy was measured as described above.

(12) Heat-resistant peelability After drying a hard coat layer (UF-TCI-1 manufactured by Kyoeisha Chemical Co., Ltd.) on the coating layer side of the release-oriented biaxially oriented polyester film specified by the method described in (11), the thickness becomes 40 μm. And then dried at 80 ° C. for 10 minutes. Thereafter, the sample was cut into a rectangle having a width of 10 mm and a length of 150 mm. Using the laminate, pressing was performed in the same manner as in (8) under the following conditions of temperature, pressing pressure, and time.
(i): 190 ° C., 4 MPa, 3 hours
(ii): 180 ° C., 3 MPa, 2 hours
(iii): After heat pressing at 170 ° C. and 1 MPa for 30 minutes, the release biaxially oriented polyester film / hard coat laminate is taken out and irradiated with 2000 mJ / cm ² of ultraviolet light to release the biaxially oriented polyester for release The peelability between the film and the hard coat layer was evaluated according to the following criteria.
A: The peel test was performed 10 times, and no film tearing or particle adhesion occurred 10 times.

B: The peel test was performed 10 times, and film breakage and particle adhesion occurred 1 to 2 times.
C: The peel test was performed 10 times, and film breakage and particle adhesion occurred 3 times or more.
Particle adhesion was evaluated by visual judgment of the hard coat layer surface.
The peel test was performed by the following method.
About the biaxially oriented polyester film / hard coat laminate for mold release after UV irradiation, Nitto Denko Co., Ltd. OPP adhesive tape (Damplon tape No. 375) is bonded to the surface of the hard coat layer side, and the width is 10 mm. A sample was cut into a rectangle with a length of 150 mm. The sample was forcibly peeled between the biaxially oriented polyester film for release and the OPP adhesive tape layer, and the occurrence of film tearing and particle adhesion was confirmed.

(13) Releasability The following criteria evaluated the releasability when the same test as in (12) was performed. A: The biaxially oriented polyester film for release was peeled at the interface with the hard coat layer, and the peel strength was 0.01 N / 10 mm or more and 0.2 N / 10 mm or less.
B: The biaxially oriented polyester film for mold release was peeled off at the interface with the hard coat layer, and the peel strength was higher than 0.2 N / 10 mm and 1 N / 10 mm or less.
C: The biaxially oriented polyester film for release was peeled off at the interface with the hard coat layer, and the peel strength was higher than 1 N / 10 mm or lower than 0.01 N / 10 mm.
The peel strength was measured by the following method.
A laminated sample of the biaxially oriented polyester film / hard coat laminate for release described in (12) and the Nitto Denko Corporation OPP adhesive tape (Damplon Tape No. 375) is used as the hard coat layer and the OPP adhesive tape. Peeling was forcibly peeled between the layers, and a 180 ° peel test was conducted using a tensile tester (Tensilon UCT-100 manufactured by Orientec Co., Ltd.) with an initial tensile chuck distance of 100 mm and a tensile speed of 20 mm / min. The measurement was performed until the peel length reached 130 mm (distance between chucks 230 mm), and the average value of the loads having a peel length of 25 mm to 125 mm was defined as the peel strength. The measurement was performed at N = 3, and the average value was adopted.

(Manufacture of polyester)
The polyester resin used for film formation was prepared as follows.

(Polyester A)
Polymerization was performed from terephthalic acid and ethylene glycol using antimony trioxide as a catalyst by a conventional method to obtain polyester A (intrinsic viscosity 0.65).

(Polyester B)
The polyester A was solid-phase polymerized by a conventional method to obtain polyester B (intrinsic viscosity 0.8).

(Particle Master C)
When producing the polyester A, an ethylene glycol slurry of agglomerated silica particles having an average particle size of 5.5 μm was added and then a polycondensation reaction was performed to prepare a particle master C having a particle concentration of 10% by mass in the polymer (inherent Viscosity 0.65).

(Particle Master D)
When the polyester A was produced, an ethylene glycol slurry of aggregated silica particles having an average particle diameter of 2.5 μm was added and then a polycondensation reaction was performed to prepare a particle master D having a particle concentration of 10% by mass in the polymer (inherent Viscosity 0.65).

(Particle Master E)
When the polyester A was produced, an ethylene glycol slurry of aggregated silica particles having an average particle size of 3.5 μm was added and then a polycondensation reaction was performed to prepare a particle master E having a particle concentration of 10% by mass in the polymer (inherent Viscosity 0.65).
(Particle Master F)
When producing the polyester A, an ethylene glycol slurry of agglomerated silica particles having an average particle size of 5.5 μm was added and then a polycondensation reaction was performed to prepare a particle master F having a particle concentration of 20% by mass in the polymer (inherent Viscosity 0.65).

(Additive)
As polyethylene wax,
(Coating layer forming solution)
The following crosslinking agent: binder resin: release agent: particles were mixed at a mass ratio shown in the table, respectively, and adjusted by diluting with pure water so that the solid content was 1%.
Crosslinking agent I: Methylated melamine / urea copolymer cross-linked resin (“Nicarac” (registered trademark) “MW12LF” manufactured by Sanwa Chemical Co., Ltd.)
Cross-linking agent II: Butylated melamine / urea copolymer cross-linked resin ("Bekkamin" (registered trademark): "J101" manufactured by Dainippon Ink & Chemicals, Inc.)
・ Binder resin I: Acrylic monomer copolymer (Nippon Carbide)
-Binder resin II: 25 mol% of terephthalic acid, 24 mol% of isophthalic acid, 1 mol% of 5-Na sulfoisophthalic acid, 25 mol% of ethylene glycol and 25 mol% of neopentyl glycol are mixed with 25% by mass of water. Diluted dispersion.
Release agent I: 200 parts of xylene and 600 parts of octadecyl isocyanate were added to a four-necked flask and heated with stirring. From the time when xylene began to reflux, 100 parts of polyvinyl alcohol having an average degree of polymerization of 500 and a degree of saponification of 88 mol% was added in small portions over a period of about 2 hours. After the addition of polyvinyl alcohol, the reaction was completed by further refluxing for 2 hours. When the reaction mixture was cooled to about 80 ° C. and added to methanol, the reaction product was precipitated as a white precipitate. This precipitate was filtered off, added with 140 parts of xylene, and heated to dissolve completely. Then, after repeating the operation of adding methanol again for precipitation several times, the precipitate was washed with methanol, dried and pulverized, and a dispersion obtained by diluting with water to 8.6% by mass was obtained.
Release agent II: 300 g of oxidized polyethylene wax having a melting point of 105 ° C., an acid value of 16 mgKOH / g, a density of 0.93 g / mL, and an average molecular weight of 5000 in an emulsification facility having an internal volume of 1.5 L equipped with a stirrer, a thermometer and a temperature controller After adding 650 g of ion-exchanged water and 50 g of decaglycerin monooleate surfactant and 10 g of 48% potassium hydroxide aqueous solution and replacing with nitrogen, it was sealed, stirred at 150 ° C. for 1 hour at high speed, cooled to 130 ° C., and a high-pressure homogenizer A wax emulsion obtained by passing the solution under a pressure of 400 atm and cooling to 40 ° C.
Mold release agent III: CF ₃ (CF ₂ ) _n CH ₂ CH ₂ OCOCH═CH ₂ (n = 5 to 11, n average = 9) 80 which is a perfluoroalkyl group-containing acrylate in a glass reaction vessel 0.0 g, acetoacetoxyethyl methacrylate 20.0 g, dodecyl mercaptan 0.8 g, deoxygenated pure water 354.7 g, acetone 40.0 g, C ₁₆ H ₃₃ N (CH ₃ ) ₃ Cl 1.0 g and C ₈ H ₁₇ C Add 3.0 g of ₆ H ₄ O (CH ₂ CH ₂ O) _n H (n = 8), add 0.5 g of azobisisobutylamidine dihydrochloride, and stir in a nitrogen atmosphere at 60 ° C. for 10 hours. A copolymer emulsion obtained by polymerization reaction.
Particles: Obtained by diluting silica particles having a number average particle diameter of 170 nm (“Snowtex” (registered trademark) MP2040 manufactured by Nissan Chemical Industries, Ltd.) with pure water so that the solid content concentration becomes 40% by weight. Water dispersion.

Example 1
The composition is as shown in the table, and the raw materials are supplied to separate single screw extruders each having an oxygen concentration of 0.2% by volume, and the A layer extruder cylinder temperature is 270 ° C. and the B layer extruder cylinder temperature is melted at 270 ° C. Then, the short tube temperature after joining the A layer and the B layer was set to 275 ° C., the die temperature was set to 280 ° C., the resin temperature was 280 ° C., and the sheet was discharged in a sheet form onto a cooling drum controlled to 25 ° C. from the T die. . At that time, a wire electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched sheet. Next, the film temperature was raised with a heated roll before stretching in the longitudinal direction, and the film was stretched 3.1 times in the longitudinal direction at a stretching temperature of 85 ° C., and immediately cooled with a metal roll whose temperature was controlled at 40 ° C. Thereafter, a corona discharge treatment was applied, and a coating layer forming solution (aqueous dispersion) adjusted to the composition shown in the table was applied using a metalling bar so that the wet thickness was 13.5 μm, and then tenter-type transverse stretching The first half temperature of stretching is 100 ° C., the middle temperature of stretching is 130 ° C., the second half of stretching temperature is 150 ° C., and the heat treatment is performed at 230 ° C. in the tenter as it is, and the annealing temperature is 170 ° C. Heat treatment is performed while relaxing 5% in the width direction, and the film thickness is 50 μm (stacking ratio is as shown in the table), and the coating layer thickness is 0.038 μm. A polyester film was obtained.

(Example 2)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the composition was changed as shown in the table.

(Example 3)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the composition was changed as shown in the table.

Example 4
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the composition was as shown in the table and the laminated structure was changed to a two-layer structure of A layer / B layer.

(Example 5)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the composition was as shown in the table and the composition was changed to a single film configuration having only the A layer.

(Example 6)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the composition was changed as shown in the table.

(Example 7)
The temperature of the A-layer extruder cylinder was 280 ° C, the temperature of the B-layer extruder cylinder was 280 ° C, the short tube temperature after joining the A-layer and B-layer was set to 285 ° C, and the die temperature was set to 290 ° C. A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 14 except that the sheet was discharged at 290 ° C. onto a cooling drum controlled to 25 ° C. from a T die.

(Example 8)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the composition was changed as shown in the table.

Example 9
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the coating composition was changed as shown in the table.

(Example 10)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the coating composition was changed as shown in the table.

(Example 11)
A biaxially oriented polyester having a film thickness of 50 μm as in Example 1 except that the stretching temperature conditions in the width direction were changed to a first half temperature of stretching 90 ° C., a middle stretching temperature 120 ° C., a second half stretching temperature 140 ° C., and a heat treatment temperature 205 ° C. A film was obtained.

(Example 13)
A biaxially oriented polyester having a film thickness of 50 μm as in Example 1 except that the stretching temperature condition in the width direction was changed to a first half temperature of stretching 100 ° C., a middle stretching temperature 130 ° C., a second half stretching temperature 160 ° C., and a heat treatment temperature 240 ° C. A film was obtained.

(Example 14)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the heat treatment time was changed to 25 seconds.

(Example 15)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the heat treatment time was changed to 15 seconds.

(Example 16)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the heat treatment time was changed to 2 seconds.

(Example 17)
A biaxially oriented polyester film having a film thickness of 50 μm and a coating layer thickness of 0.023 μm was obtained in the same manner as in Example 1 except that the wet thickness after application of the coating layer forming solution was changed to 8.2 μm.

(Example 18)
A biaxial film having a film thickness of 50 μm and a coating film layer thickness of 0.5 μm in the same manner as in Example 1 except that the solid content concentration of the solution for forming a coating film layer was 10% and the wet thickness after coating was 17.8 μm. An oriented polyester film was obtained.

(Example 19)
A biaxial film having a film thickness of 50 μm and a coating film layer thickness of 0.095 μm in the same manner as in Example 1 except that the solid content concentration of the coating layer forming solution was 5% and the wet thickness after coating was 16.9 μm. An oriented polyester film was obtained.

(Example 20)
A biaxially oriented polyester film having a film thickness of 50 μm and a coating layer thickness of 0.055 μm was obtained in the same manner as in Example 1 except that the wet thickness after application of the coating layer forming solution was 19.6 μm.

(Example 21)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the coating composition was changed as shown in the table.

(Example 22)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the coating composition was changed as shown in the table.

(Example 23)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the coating composition was changed as shown in the table.

(Example 24)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the coating composition was changed as shown in the table.

(Example 25)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the coating composition was changed as shown in the table.

(Example 26)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the coating composition was changed as shown in the table.

(Example 27)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the coating composition was changed as shown in the table.

(Example 28)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the coating composition was changed as shown in the table.

(Comparative Example 1)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the composition was changed as shown in the table.

(Comparative Example 2)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the composition was changed as shown in the table.

(Comparative Example 3)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the laminated structure was changed as shown in the table.

(Comparative Example 4)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the coating composition was changed as shown in the table.
(Comparative Example 5)
A biaxially oriented polyester film having a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the coating composition was changed as shown in the table.

The release biaxially oriented polyester film of the present invention has a low glossiness and a high heat resistance of the release surface, and therefore can be suitably used for a heat-resistant release film for circuit process films that require a matte tone. .

Claims (6)

40 masses of melamine resin in the A layer of the base film having a polyester A layer containing 0.1 mass% or more and 10 mass% or less of inorganic particles and / or organic particles, with the entire polyester A layer being 100 mass%. A biaxially oriented polyester film for mold release, wherein a coating layer containing from 90% to 90% by mass is laminated, and the glossiness of the surface on which the coating layer is laminated is 30 or less.
The biaxially oriented polyester film for mold release according to claim 1, wherein the surface free energy of the surface on which the coating layer is laminated is 25 mN / m or more and 40 mN / m or less. The biaxially oriented polyester film for mold release according to claim 1 or 2, wherein the thickness of the coating layer is 0.02 µm or more and 0.5 µm or less. The biaxially oriented polyester film for mold release according to any one of claims 1 to 3, wherein the amount of carboxyl end groups of the polyester A layer is 20 eq / t or less. The average value of tear propagation resistance in an arbitrary one direction (X direction) of the film and a direction orthogonal to the X direction (Y direction) is 5 N / mm or more. Biaxially oriented polyester film. The average value of the tear propagation resistance in any one direction (X direction) and the direction orthogonal to the X direction (Y direction) after heat pressing for 2 hours under the condition of 180 ° C. × 3 MPa is 5 N / mm It is the above, The biaxially-oriented polyester film for mold release in any one of Claims 1-5.