JP6443155B2 - Biaxially oriented polyester film for mold release - Google Patents

Description

The present invention relates to a release biaxially oriented polyester film.

  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).

JP 2013-129077 A JP 2006-312263 A

However, although the film described in Patent Document 1 is excellent in matte tone, the anchor effect due to the unevenness of the film surface becomes a heavy peeling factor, and the film cannot be peeled at the time of peeling, or the film is broken or adhered. It may be difficult to maintain process stability in the circuit manufacturing process.
In addition, the film described in Patent Document 2 has excellent heat resistance and can be applied to high-temperature and high-load processing conditions. However, due to the uneven distribution of the convex portions on the surface, a release layer or Since adhesion spots are generated when the hard coat layer is laminated, problems such as occurrence of peeling force spots may occur when zipping or changing the peeling direction, resulting in a problem of reduced workability.
An object of the present invention is to eliminate the above-described problems of the prior art. That is, by containing inorganic particles and / or organic particles, and controlling the surface roughness of the film and the interparticle distance on the outermost surface within an appropriate range, in a circuit formation process that requires a matte tone, the peeling force spots are small, An object of the present invention is to provide a biaxially oriented polyester film for release which is particularly suitable as a heat-resistant release film having good processability and high process compatibility.

The gist of the present invention for solving this problem is that the polyester A layer containing inorganic particles and / or organic particles is provided in at least one outermost layer, and the center line of the polyester A layer surface of the outermost layer is provided. It is a biaxially oriented polyester film for mold release having an average roughness Ra of 0.38 μm or more and 1.0 μm or less and an average length RSm of the roughness curve element on the surface of the polyester A layer of 10 μm or more and 80 μm or less.

The biaxially oriented polyester film for mold release of the present invention contains inorganic particles and / or organic particles, and requires a matte tone by controlling the surface roughness of the film and the distance between the outermost particles within an appropriate range. In a circuit formation process, it can be suitably used as a heat-resistant release film having a small processability and having good peelability and high process compatibility.

A surface roughness curve is shown.

  The polyester constituting the biaxially oriented polyester film for mold release according to the present invention is a general term for polymer compounds having an ester bond as the main bond in the main chain. The polyester resin can be usually obtained by polycondensation reaction of dicarboxylic acid or its derivative with glycol or its derivative.

  In the present invention, from the viewpoint of appearance, heat resistance, dimensional stability and economy, 60 mol% or more of the glycol units constituting the polyester are structural units derived from ethylene glycol, and 60 mol% or more of the dicarboxylic acid units are terephthalic. A structural unit derived from an acid is preferred. Here, the dicarboxylic acid unit (structural unit) or the diol unit (structural unit) means a divalent organic group from which a portion to be removed by polycondensation has been removed. It is represented by

Dicarboxylic acid unit (structural unit): —CO—R—CO—
Diol unit (structural unit): —O—R′—O—
(Where R and R ′ are divalent organic groups)
In addition, when a trivalent or higher carboxylic acid or alcohol such as trimellitic acid unit or glycerin unit or a derivative thereof is included, the trivalent or higher carboxylic acid or alcohol unit (structural unit) is similarly obtained by polycondensation. The trivalent or higher valent organic group from which the part to be removed is removed is meant.

  Glycols or derivatives thereof that give polyester for use in the present invention include, in addition to ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, Aliphatic dihydroxy compounds such as 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, polyoxyalkylene glycols such as diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol , Alicyclic dihydroxy compounds such as spiroglycol, aromatic dihydroxy compounds such as bisphenol A and bisphenol S, and derivatives thereof. Among them, diethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol are heat resistant and easy to handle. Preferably used.

  In addition to terephthalic acid, the dicarboxylic acid or derivative thereof that provides the polyester used in the present invention includes isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenoxyethanedicarboxylic acid. Acids, aromatic dicarboxylic acids such as 5-sodiumsulfone 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, etc. Alicyclic dicarboxylic acids, oxycarboxylic acids such as paraoxybenzoic acid, and derivatives thereof. Examples of dicarboxylic acid derivatives include dimethyl terephthalate, diethyl terephthalate, 2-hydroxyethyl methyl terephthalate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl isophthalate, dimethyl adipate, diethyl maleate, and dimethyl dimer. An esterified product can be mentioned. Of these, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and esterified products thereof are preferably used from the viewpoint of heat resistance and handleability.

  The biaxially oriented polyester film for mold release of the present invention needs to have a polyester A layer containing inorganic particles and / or organic particles in at least one outermost layer in order to achieve a matte appearance.

  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, Bengala, molybdenum red, cadmium red, red lead yellow lead, chromium permillion, blue pigments such as ultramarine, bitumen, cobalt blue, cerulean blue, chromium oxide, pyridian, emerald green, cobalt green, yellow lead, cadmium yellow, yellow iron oxide , Titanium yellow, manganese violet, mineral violet, titanium dioxide, barium sulfate, zinc white, zinc sulfate, carbon black, black iron oxide, etc., organic particles such as styrene, silicone, acrylic acid, methacrylic acid, polyester Le acids, divinyl compounds, condensed azo, phthalocyanine, quinacridone, dioxazine, isoindolinone, quinophthalone, particles can be used to like constituents anthraquinone. Among these, it is preferable to use inorganic particles such as heat-resistant 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.

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 1% by mass or more based on 100% by mass of the entire polyester A layer in order to achieve a matte appearance. It is preferably contained in an amount of 10% by mass or less, but from the viewpoint of preventing the appearance of matte appearance and film breakage at the time of peeling, the entire polyester A layer is preferably contained in an amount of 2% by mass to 8% by mass with 100% by mass. More preferably, it is contained in an amount of from 6% by mass to 6% by mass.
In addition, the inorganic particles and / or organic particles used in the present invention preferably have an average particle size of 2 μm or more and 10 μm or less, more preferably 3 μm or more and 9 μm or less from the viewpoint of matte appearance and tear propagation resistance. The thickness is most preferably 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).

  In the biaxially oriented polyester film for mold release of the present invention, the center line average roughness of the surface of the outermost polyester A layer needs to be 0.38 μm or more and 1.00 μm or less. It is preferable that the center line average roughness of the outermost polyester A layer surface is 0.38 μm or more and 1.00 μm or less because it is easy to achieve releasability and matte appearance as a circuit process film. When the center line average roughness is less than 0.38 μm, the mat feeling of the transfer body is insufficient, and the unevenness of the surface layer is small, so that the adhesion of the adhesive layer laminated on the surface layer is strong, and there is a concern of heavy peeling. When the center line average roughness is larger than 1.00 μm, the matte feeling is sufficient, but the releasability may be lowered and the matte tone may be insufficient. More preferably, the center line average roughness of the outermost polyester A layer surface is 0.45 μm or more and 0.65 μm or less. When the center line average roughness on the polyester A layer side of the outermost layer is 0.45 μm or more and 0.65 μm or less, 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 hot press. However, since the appearance of the functional layer is an excellent matte appearance, it is very preferable. The method of setting the center line average roughness of the outermost polyester A layer surface to 0.38 μm or more and 1.00 μm 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 The polyester A layer which contains 1 mass% or more and 10 mass% or less of the whole polyester A layer as 100 mass% is mentioned.

In the biaxially oriented polyester film for release of the present invention, the average length (RSm) of the roughness curve element on the surface of the outermost polyester A layer is preferably 10 μm or more and 80 μm or less. RSm here is obtained according to JIS B 0601 (2001), and represents the average length between roughness curve elements in the reference length. That is, when the number of peaks of the roughness curve is m and the distance between each peak is W ₁ , W ₂ , W ₃ ... W _m in the reference length (Lr) in FIG. RSm can be obtained by dividing the sum of the lengths of W _{1 to} W _m by the number m of peaks of the roughness curve as shown in FIG. RSm is a physical property value representing the unevenness of the film surface, and the larger the value, the larger the distance between the unevenness. It is thought that the peeling spot increases. From the viewpoint of suppressing such peeling-off spots, it is necessary to set the RSm to 10 μm or more and 80 μm or less. However, when RSm is larger than 80 μm, the peeling-off spots are different for each zipping or peeling direction. It may occur and is unsuitable because it impairs workability. RSm is most preferably 20 μm or more and 60 μm or less.

As a method for setting the characteristics of the biaxially oriented film for mold release within the above range, the temperature rising crystallization temperature Tcc of the polyester A layer is set to 140 ° C. or less, and in the film production process, it is continuous with the transverse stretching process. For example, the temperature gradient between the heat treatment steps may be 80 ° C. or less. Under general process conditions, the convex portions are flattened in the heat treatment step, and the small convex portions are buried, resulting in an increase in the distance between the large convex portions. On the other hand, by reducing the temperature gradient between the transverse stretching process and the heat treatment process and setting it as a stepwise temperature increase condition, the surface layer gradually crystallizes after transverse stretching, the structure is fixed, and the projections in the heat treatment process are flattened. Suppress.

  In the biaxially oriented polyester film for release of the present invention, the melting point peak observed on the highest temperature side in the differential scanning calorimetry (DSC) of the polyester A layer is preferably 250 ° C. or higher and 270 ° C. or lower. Here, the polyester A layer may exhibit a plurality of melting points. It is preferable that the melting point of the polyester A layer is 250 ° C. or higher and 270 ° C. or lower because partial melting and low elasticity can be suppressed even in a high-temperature processing step, so that it can be applied to a wide range of processing conditions. When the melting point of the polyester A layer is less than 250 ° C., it may be difficult to control the peeling force due to low elasticity at the time of processing at a high temperature and increased adhesion with the adhesive layer. On the other hand, when the melting point of the polyester A layer is higher than 270 ° C., the film conformability is deteriorated, so that the workability is deteriorated.

The biaxially oriented polyester film for mold release of the present invention preferably has a surface energy of 35 to 43 mN / m measured on the surface of the outermost polyester A layer. More preferably, it is 38-42 mN / m. The present inventors have found that by controlling the surface energy of the outermost surface of the polyester A layer to 35 to 43 mN / m, a very advantageous characteristic as a release film for circuit formation is satisfied. If the surface energy measured on the outermost polyester A layer surface is smaller than 35 mN / m, the release film may be naturally peeled off during transportation or storage. Moreover, when the surface energy measured about the polyester A layer surface of outermost layer is larger than 43 mN / m, peelability will fall and a film and an adhesive layer may not peel well at the time of transcription | transfer.
The biaxially oriented polyester film for release of the present invention preferably has a color tone L value of 50 or more and 90 or less from the viewpoint of visibility at the time of peeling. By setting the color tone L value to 50 or more and 90 or less, it is possible to ensure appropriate visibility. The color tone L value is more preferably from 60 to 80, and most preferably from 65 to 75. As a method for setting the color tone L value of the biaxially oriented polyester film for release of the present invention to 50 or more and 90 or less, for example, the entire layer is 100% by mass, and titanium dioxide is 0.1% by mass or more and 5% by mass or less. It is preferable to have a layer containing 0.5% by mass or more and 4% by mass or less. Titanium dioxide may be contained in the polyester A layer as the outermost layer, and the biaxially oriented polyester film for release is a polyester A layer in addition to the outermost layer (hereinafter referred to as B layer, C layer. May be contained in each layer. When the color tone L value is less than 50, the visibility is insufficient, so that the film may be forgotten to be peeled off, which is unsuitable because the yield decreases. When the color tone L value is greater than 90, the amount of the additive for adjusting the color tone becomes large, and therefore, tearing starting from the additive tends to occur during film formation.

  The biaxially oriented polyester film for mold release according to the present invention is a block copolymer of polybutylene terephthalate and polyoxyalkylene glycol formed on the outermost polyester A layer from the viewpoint that the surface shape is a preferable mode and the peelability is good. Is preferably contained in an amount of 5 wt% to 30 wt%. More preferably, they are 8 weight% or more and 25 weight%, Most preferably, they are 10 weight% or more and 18 weight% or less. When a specific amount of flexible polyoxyalkylene glycol is contained, the crystallization speed is increased and Tcc is decreased, so that the surface shape of the present invention can be achieved. The structure of the polyoxyalkylene glycol used in the film of the present invention is not particularly limited, but polytetramethylene glycol is preferable from the viewpoint of heat resistance and crystallinity, and is preferably copolymerized as a glycol component of the polyester. .

In the biaxially oriented polyester film for release of the present invention, it is preferable to use a layer having releasability by laminating it on the outermost polyester A layer from the viewpoint of improving releasability.
In this invention, it is preferable to laminate | stack the release layer containing a melamine resin and a release agent from a heat resistant viewpoint at the time of a heating. From the viewpoint of heat resistance and release stability, the content of the melamine resin in the release layer is preferably 50% by mass or more.
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. Moreover, it is preferable that the mold release layer of this invention contains binder resin other than binder resin and a mold release agent from a viewpoint of film forming property and extending | stretching followability. As the binder resin, a polyester resin, an acrylic resin, and a urethane resin are preferably used, and an acrylic resin is particularly preferably used. Examples of the acrylic resin include a homopolymer or copolymer of (meth) acrylic acid alkyl ester, a (meth) acrylic acid ester copolymer having a curable functional group at the side chain and / or main chain terminal, Examples of the curable 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, as a mold release agent contained in the mold release layer of this invention, a fluorine compound, a long-chain alkyl compound, a wax compound etc. are mentioned, for example. These release agents may be used alone or in combination.

  The fluorine compound that can be used in the present invention 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. Examples thereof include a containing ether compound and a long-chain alkyl group-containing quaternary ammonium salt. It is preferable that the long-chain alkyl compound is a polymer compound because the component derived from the release layer on the surface of the counterpart substrate that is bonded when the release film is peeled can be suppressed.

  The wax that can be used in the present invention 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 release layer, the adhesion and release force with the release layer laminated and peeled on the release 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 release layer of the present invention may contain inert particles for the purpose of improving the adhesion and slipperiness of the release layer. Specific examples of the inert particles include silica, alumina, kaolin, calcium carbonate, titanium oxide, and organic particles. Next, although the example of the specific manufacturing method of the biaxially-oriented polyester film for mold release of this invention is described, this invention is limited to this example and is not interpreted.

  When making a laminated polyester film having a polyester A layer and a polyester B layer, first, as polyester A used for the polyester A layer, silica particles having an average particle diameter of 5 μm in polyethylene terephthalate resin (a) and polyethylene terephthalate resin (a) Of polyethylene terephthalate resin (a ′) containing particles and polytetramethylene glycol copolymer polybutylene terephthalate resin (a ″) are weighed at a predetermined ratio. Polyester B used for the polyester B layer is polyethylene. A terephthalate resin (a) and a polytetramethylene glycol copolymer polybutylene terephthalate resin (a ") are used.

  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.

  The biaxially oriented polyester film for mold release 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.

  As a draw ratio in such a drawing method, 2.8 to 3.4 times, more preferably 2.9 to 3.3 times in the longitudinal direction is employed. The stretching speed is preferably 1,000% / min or more and 200,000% / min or less. Moreover, it is preferable that the extending | stretching temperature of a longitudinal direction shall be 70 degreeC or more and 100 degrees C or less. The stretching ratio in the width direction is preferably 2.8 times or more and 3.8 times or less, and more preferably 3 times or more and 3.6 times or less. The stretching speed in the width direction is desirably 1,000% / min or more and 200,000% / min or less. The stretching temperature in the width direction is desirably 80 ° C. or higher and 150 ° C. or lower. However, for the purpose of forming the surface shape that is the feature of the present invention on the surface of the release film, The stretching temperature is preferably set so that the difference is within 80 ° C.

  Further, after the biaxial stretching, the film is subjected to heat treatment. This heat treatment is performed for 1 to 30 seconds while maintaining a constant length or sequentially shrinking in an oven. In this heat treatment process, it is preferable to set the temperature rising conditions from the first half of the process stepwise, the first half temperature of the heat treatment is set to −30 ° C. or more from the latter half temperature of the heat treatment, and −15 ° C. or less from the second half temperature of the heat treatment. The conditions for setting to ° C are preferred. In order to further reduce the heat shrinkage rate, it is also preferable to perform slow cooling at 140 ° C. or more and less than 180 ° C. after the heat treatment.

Furthermore, the release layer can be coated in-line in order to ensure stable release properties. As a method of providing the coating layer in-line in the film manufacturing process, at least uniaxially stretched film with a coating layer composition dispersed in water is uniformly applied using a metalling ring bar or gravure roll. In addition, a method of drying the coating agent while performing stretching is preferable. In this case, the thickness of the release layer is preferably 0.02 μm or more and 0.1 μm or less. Also, various additives such as antioxidants, heat stabilizers, ultraviolet absorbers, infrared absorbers, pigments, dyes, organic or inorganic particles, antistatic agents, nucleating agents, etc. may be added to the release layer. Good.
The biaxially oriented polyester film for mold release of the present invention contains inorganic particles and / or organic particles, and the matte tone is controlled by controlling the center line average roughness of the film and the inter-particle distance on the outermost surface within an appropriate range. It can be suitably used for a heat-resistant release film such as a necessary process film for a circuit.

(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) Identification of particle-containing layer 1 g of 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 then the liquid was centrifuged to settle the particles, and the supernatant was removed to confirm the presence of particles in the layer. 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. 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.

(3) Centerline average roughness Ra
According to JIS B 0601, centerline average roughness centerline roughness Ra was measured using VertScan2.0 R5300GL-Lite-AC manufactured by Ryoka System Co., Ltd. The measurement is performed on the surface of the polyester A layer side, and when both surface layers of the film are A layers, N = 3 for each side of the film (the surface with the largest Ra is the I surface and the opposite surface is the II surface). The average value was adopted. The details of the measurement conditions are as follows.
Manufacturer: Ryoka System Co., Ltd.
Device name: VertScan 2.0 R5300GL-Lite-AC
Measurement conditions: CCD camera SONY HR-57 1/2 inch
Objective lens 5x
Intermediate lens 0.5x
Wavelength filter 530nm white
Measurement mode Focus
Measurement software: VS-Measure Version5.5.1
Analysis software: VS-Viewer Version5.5.1
Measurement area: 1.252 × 0.939 mm ²
(4) Average length RSm of roughness curve elements
It calculated | required according to JISB0601. The measurement was performed using Ryoka System VertScan 2.0 R5300GL-Lite-AC, and the surface shape was obtained by correcting the surface of the captured image with polynomial fourth-order approximation using the attached analysis software. The measurement conditions are as follows. In the measurement, first, the A layer of the laminated film was specified, and the surface on the A layer side was measured. For the identification of the A layer, after confirming the particles contained in the outermost layer of the film by the method described in (2), the center line average roughness is measured by the method described in (3). When the roughness was 0.38 μm or more and 1.00 μm or less, the polyester layer was designated as A layer. In the case where both sides of the film satisfy the conditions as the A layer, the measurement was carried out with the A layer on both sides. In the biaxially oriented polyester film for release of the present invention, the measurement is performed on the surface on the polyester A layer side. When both surface layers of the film are A layers, both surfaces of the film (the surface with the largest Ra is the I surface). , The opposite surface is the II surface), N = 3, and the average value was adopted as the RSm of each surface.
Manufacturer: Ryoka System Co., Ltd.
Device name: VertScan 2.0 R5300GL-Lite-AC
Measurement conditions: CCD camera SONY HR-57 1/2 inch
Objective lens 5x
Intermediate lens 0.5x
Wavelength filter 530nm white
Measurement mode Focus
Measurement software: VS-Measure Version5.5.1
Analysis software: VS-Viewer Version5.5.1
Measurement area: 1.252 × 0.939 mm ² .

(5) Crystallization temperature Tcc
Using a scanning differential calorimeter RDC220 (DSC) manufactured by Seiko Denshi Kogyo Co., Ltd., a 5 mg sample was measured at a rate of 20 ° C./min under a nitrogen atmosphere in accordance with a plastic transition heat measurement method (JIS K7122). The temperature was raised to 300 ° C. and held for 5 minutes, then cooled to 10 ° C. at a cooling rate of 20 ° C./min, and again raised at a rate of 20 ° C./min. The peak temperature of the exothermic peak accompanying crystallization of the resin was defined as the melting point (Tcc). 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.

(6) Using a melting point differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., RDC220), measurement and analysis were performed in accordance with JIS K7121-1987 and JIS K7122-1987. Using 5 mg of a polyester film as a sample, the temperature at the apex of the endothermic peak obtained from the DSC curve when the temperature was raised from 25 ° C. to 300 ° C. at 20 ° C./min was defined as the melting point. When a plurality of endothermic peaks existed, the peak on the highest temperature side was taken as the melting point. In the case of a laminated film, the melting point of each layer alone can be measured by scraping each layer of the film according to the laminated thickness.

(7) Method for calculating surface energy As the measuring solution, water, ethylene glycol, formamide and diiodomethane were used, and each liquid was measured using a contact angle meter (CA-D type manufactured by Kyowa Interface Science Co., Ltd.). The static contact angle with respect to the film surface was determined. Each liquid is measured five times, and each component of the average contact angle (θ) and the surface tension of the measurement liquid (j) is substituted into the following equation, and the simultaneous equations consisting of four equations are expressed as γL, γ +, γ− Solved about.

(ΓLγjL) 1/2 + 2 (γ + γj−) 1/2 + 2 (γj + γ−) 1/2
= (1 + cos θ) [γjL + 2 (γj + γj−) 1/2] / 2
However, γ = γL + 2 (γ + γ−) 1/2
γj = γjL + 2 (γj + γj−) 1/2
Here, γ, γL, γ +, and γ− are the surface energy of the film surface, the long-range force term, the Lewis acid parameter, and the Lewis base parameter, respectively, and γj, γjL, γj +, and γj− are respectively used. The surface energy, long-range force term, Lewis acid parameter, and Lewis base parameter of the measurement liquid are shown. 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)).
In the measurement, the A layer of the laminated film was first identified by the method described in (4), and the surface on the A layer side was measured. Moreover, in the biaxially oriented polyester film for mold release of the present invention, when both surface layers of the film are A layers, N = 3 is performed for each of the film both surfaces (I surface / II surface), and the average value is set for each. Adopted as surface energy of surface.

(8) Color tone L value Based on JIS-Z-8722 (2000), using a spectroscopic color difference meter (SE-2000 manufactured by Nippon Denshoku Industries Co., Ltd., light source halogen lamp 12V4A, 0 ° to −45 ° post spectroscopic method) The color tone L value was measured by the reflection method. The measurement was performed in an atmosphere at a temperature of 23 ° C. and a humidity of 65%. Measurements were made by selecting five arbitrary positions on the film, and the average value was adopted. (9) Heat-resistant release property The biaxially oriented polyester film for release of the present invention was coated with a hard coat layer (Kyoeisha Chemical Co., Ltd.). UF-TCI-1) manufactured was coated to a thickness of 40 μm after drying and 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, a press machine heated to a temperature of 160 ° C. for both the upper mold temperature and the lower mold temperature was used, and a 0.2 mm thick aluminum plate / 0.125 mm thick polyimide film (manufactured by Toray DuPont) 1 Kapton 500H / V) / biaxially oriented polyester film for mold release / HC laminate / 0.125 mm thick polyimide film (Toray DuPont Kapton 500H / V) /0.2 mm thick aluminum plate Heat pressing was performed for 1 hour under the condition of 5 MPa. After the heat press, the biaxially oriented polyester film / HC laminate is taken out, irradiated with ultraviolet rays having an illuminance of 2000 mJ / cm ² , and the releasability between the biaxially oriented polyester film and the HC layer is evaluated according to the following criteria. The above was regarded as passing.
A: A mold release test was performed 10 times, and no film tearing or adhesion occurred 10 times.

B: The mold release test was performed 10 times, and film tearing and adhesion occurred once.
C: The mold release test was performed 10 times, and film tearing and adhesion occurred twice or more.

(10) Matte appearance transferability The appearance of the peeled HC layer (peeling surface) obtained in (9) was observed, and the matte appearance transferability was evaluated according to the following criteria. In addition, 60 degree glossiness was measured using the digital variable angle glossiness meter UGV-5D by Suga Test Instruments according to the method prescribed | regulated to JIS-Z-8741 (1997). Measurement was performed at n = 5, and an average value excluding the maximum value and the minimum value was adopted.
A: 60 degrees The glossiness is 15 or less.

B: 60 degree glossiness is 25 or less.
C: 60 degree glossiness is larger than 25.
(11) Uniform peelability The peel strength of the laminate of the biaxially oriented polyester film and the HC layer after ultraviolet irradiation obtained in (9) was measured in the following manner. Forcibly peeled between the biaxially oriented polyester film and HC layer, and 180 ° peeled using a tensile tester (Orientec Tensilon UCT-100) with an initial tensile chuck distance of 100 mm and a tensile speed of 20 mm / min. A test was conducted. 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 in each of two directions in which the peeling direction was changed by 90 degrees in the plane. After calculating the average value of N = 3 for each of the obtained peel strengths in the two directions, the absolute value of the difference was taken and evaluated according to the following criteria, and B or higher was regarded as acceptable.
A: The absolute value of the difference in peel strength in two directions different by 90 degrees was 0 or more and less than 0.10 N / 10 mm.
B: The absolute value of the difference in peel strength in two directions different by 90 degrees was 0.10 or more and less than 0.50 N / 10 mm.
C: The absolute value of the difference in peel strength in two directions different by 90 degrees was 0.50 N / 10 mm or more.

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

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

(Polyester B)
A polyethylene terephthalate particle master having an intrinsic viscosity of 0.65, in which polyester A contains aggregated silica particles having a number average particle size of 3.5 μm at a particle concentration of 20% by mass.

(Polyester C)
After heating up to 40 degreeC and making it a uniform solution, 0.054 weight part of tetra-n-butyl orthotitanate and 0.054 weight part of monohydroxybutyltin oxide were added, and esterification reaction was performed by the conventional method. Next, 0.066 parts by weight of tetra-n-butyl orthotitanate was added and a polycondensation reaction was performed under reduced pressure to obtain a polybutylene terephthalate resin having an intrinsic viscosity of 0.88. Thereafter, solid-state polymerization was performed to obtain a polybutylene terephthalate resin having an intrinsic viscosity of 1.20. (Polyester D)
A mixture of 100 parts by weight of terephthalic acid and 110 parts by weight of 1,4-butanediol was heated to 140 ° C. under a nitrogen atmosphere to obtain a homogeneous solution, and then 0.054 parts by weight of tetra-n-butyl orthotitanate, 0.054 parts by weight of hydroxybutyltin oxide was added, and esterification was performed by a conventional method. Next, 0.066 parts by weight of tetra-n-butyl orthotitanate was added and a polycondensation reaction was performed under reduced pressure to obtain a polybutylene terephthalate resin having an intrinsic viscosity of 0.88. Thereafter, solid-state polymerization was performed to obtain a polybutylene terephthalate resin having an intrinsic viscosity of 1.20.

(Polyester D)
Hytrel 7247 manufactured by Toray-DuPont was used.
(Polyester E)
Polyethylene terephthalate particle master (inherent viscosity 0.6) containing 50% by mass of anatase-type titanium dioxide in polyester A.

(Polyester F)
To a mixture of 88 parts by mass of dimethyl terephthalate, 12 parts by mass of dimethyl isophthalate, and 67 parts by mass of ethylene glycol, 0.08 parts by mass of magnesium acetate, 0.
022 parts by mass was added, the temperature was gradually raised, and a transesterification reaction was finally carried out while distilling 220 ° C. methanol. Subsequently, 0.020 parts by mass of an 85% aqueous solution of phosphoric acid was added to the transesterification reaction product, and then transferred to a polycondensation reaction kettle. The temperature of the reaction system is gradually reduced while heating in the polymerization kettle, and finally the temperature is raised to 280 ° C. and 1 hPa and the pressure is reduced.
The polycondensation reaction is carried out until it becomes, then discharged into a strand, cooled, cut and polyethylene terephthalate resin in which 12 mol% of the isophthalic acid component is copolymerized with respect to the dicarboxylic acid component in the resin (by-product of the diethylene glycol component). The copolymerization rate was 1.8 mol%). (Release layer forming solution (water dispersion)
The following crosslinking agent: binder resin: release agent: particles were mixed at a mass ratio of 60:23:17, respectively, and diluted with pure water to adjust the solid content to 1%.
・ Crosslinking agent: Methylated melamine / urea copolymer cross-linked resin (“Nicarac” (registered trademark) “MW12LF” manufactured by Sanwa Chemical Co., Ltd.))
-Binder resin I: Acrylic monomer copolymer (Nippon Carbide)
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 B layer is set to 275 ° C, the die temperature is set to 280 ° C, and the resin temperature is 280 ° C. did. 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, the film was stretched 3.5 times in the width direction at a stretching first half temperature of 110 ° C., a stretching middle temperature of 125 ° C., and a stretching latter half temperature of 140 ° C. in a tenter type transverse stretching machine, and the first half heat treatment at 220 ° C. and the latter half of the heat treatment in the tenter. After heat treatment at 240 ° C., heat treatment was performed while relaxing 5% in the width direction at a slow cooling temperature of 170 ° C., and the film thickness was 50 μm (lamination ratio is as shown in the table). A layer / B layer / A layer A biaxially oriented polyester film having a three-layer structure 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 changed as shown in the table.

(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 changed as shown in the table.

(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)
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 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 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 first half temperature of the heat treatment was changed to 210 ° C.

(Example 11)
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 12)
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 13)
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 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 composition was changed as shown in the table.

(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 composition was changed as shown in the table.

(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 composition was changed as shown in the table.

(Example 17)
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 18)
The composition is as shown in the table, and the raw material is supplied to a single screw extruder having an oxygen concentration of 0.2% by volume. The extruder cylinder temperature is melted at 270 ° C., the short tube temperature is 275 ° C., and the die temperature is 280 ° C. The resin temperature was 280 ° C., and the sheet was discharged in a sheet form onto a cooling drum whose temperature was controlled from a T die to 25 ° C. Thereafter, in the same manner as in Example 1, a biaxially oriented polyester film having a single film structure consisting of only an A layer having a film thickness of 50 μm was obtained.

(Example 19)
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 B layer is set to 275 ° C, the die temperature is set to 280 ° C, and the resin temperature is 280 ° C. did. 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 is performed, and a release layer forming solution (aqueous dispersion) is applied using a metalling bar so that the wet thickness becomes 13.5 μm, and the first half temperature of stretching is 110 with a tenter type horizontal stretching machine. , Intermediate stretching temperature 125 ° C., stretching second half temperature 140 ° C., stretched 3.5 times in the width direction, followed by heat treatment in the tenter as it was at the first half of heat treatment 220 ° C. and the second half of heat treatment 240 ° C., followed by a slow cooling temperature 170 Biaxially oriented in a three-layer configuration of A layer / B layer / A layer with a film thickness of 50 μm (lamination ratio is as shown in the table) and a release layer thickness of 40 nm at 5 ° C. with 5% relaxation in the width direction. A polyester film was obtained.
(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 first half temperature of the heat treatment was changed to 230 ° C.
(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 first half temperature of the heat treatment was changed to 240 ° C.
(Comparative Example 3)
A biaxially oriented polyester film with a film thickness of 50 μm was obtained in the same manner as in Example 1 except that the intermediate stretching temperature was 110 ° C., the latter half temperature was 120 ° C., and the first half temperature was 220 ° C.
(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 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 composition was changed as shown in the table.
(Comparative 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.
(Comparative Example 7)
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 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.
(Comparative 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 composition was changed as shown in the table.
(Comparative 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 composition was changed as shown in the table.
(Comparative Example 11)
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 12)
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 13)
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.

The biaxially oriented polyester film for mold release of the present invention contains inorganic particles and / or organic particles, and controls the center line average roughness of the film and the inter-particle distance on the outermost surface to within an appropriate range, thereby causing peeling force unevenness. Therefore, it can be suitably used for heat-resistant release films such as circuit process film applications that require a matte tone.

1: Roughness curve

Claims (7)

The polyester A layer containing inorganic particles and / or organic particles has at least one outermost layer, and the center line average roughness Ra of the outermost layer polyester A layer surface is 0.38 μm or more and 1.0 μm or less, A biaxially oriented polyester film for mold release, wherein the average length RSm of the roughness curve element on the surface of the polyester A layer is 10 μm or more and 80 μm or less. The biaxially oriented polyester film for mold release according to claim 1, wherein the highest melting point peak of the polyester A layer is observed at 250 ° C or higher and 270 ° C or lower by differential scanning calorimetry (DSC). The biaxially oriented polyester film for mold release according to claim 1 or 2, wherein the surface energy of the outermost polyester A layer is 35 mN / m or more and 43 mN / m or less. The biaxially oriented polyester film for mold release according to any one of claims 1 to 3, wherein the color tone L value is 50 or more and 90 or less. The biaxially oriented polyester film for mold release according to any one of claims 1 to 4, wherein the polyester A layer contains 5% by weight to 30% by weight of a polyester having butylene terephthalate as a main repeating unit. The biaxially oriented polyester film for mold release according to any one of claims 1 to 5, wherein the polyester A layer contains 5% by weight to 30% by weight of a polyester copolymerized with polyoxyalkylene glycol. The laminated body which provided the release layer in the biaxially-oriented polyester film for mold release in any one of Claims 1-6.

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