JP5675246B2 - Multilayer film and method for producing the same - Google Patents

Description

  The present invention relates to a multilayer film suitable as a release film capable of suppressing migration of an oligomer contained in a polyester film to a silicone resin layer, and a method for producing the same.

  A polyester film on which a silicone resin layer is laminated is used as a release film in applications such as an adhesive film and a process film for molding a resin sheet. Recently, it is also used as a process film for various optical applications such as a liquid crystal display such as a liquid crystal polarizing plate (hereinafter abbreviated as LCD) and a plasma display panel (hereinafter abbreviated as PDP).

  When a polyester film laminated with a silicone resin is used as a process film for various optical applications as described above, high transparency and visibility such as viewing through light are regarded as important. It is desirable that there are as few foreign objects as possible.

  For example, in the case of a liquid crystal polarizing plate, when an adhesive is applied and then heat-treated in the drying process, oligomers that have leached from the inside of the film surface contaminate the inside of the process or are transferred to the adhesive layer of the polarizing plate. When the LCD is manufactured by being attached to a glass substrate, there may be a problem that the brightness of the LCD is lowered.

  As a method for solving such a problem, a method for reducing oligomer components contained in a polyester film (for example, Patent Document 1: JP 2000-141568 A) or an ultraviolet curable type such as glycerol diepoxy (meth) acrylate. A method of applying a sealing agent (Patent Document 1: Japanese Patent Application Laid-Open No. 2002-240203) has been proposed.

  As a method for improving the surface smoothness of a polyester film, a method of forming an acrylate compound layer on at least one side of a polyester film (Patent Document 2: JP-A-2006-159651) has been proposed.

  However, even if the acrylate compounds used in the examples of Patent Document 1 or Patent Document 2 are used, the effect of suppressing the migration of the silicone curing inhibitor contained in the polyester film to the silicone resin layer is insufficient.

JP 2000-141568 A JP 2002-240203 A JP 2006-159651 A

  An object of this invention is to obtain the multilayer film suitable as a release film which can suppress the transfer to the silicone resin layer of the oligomer contained in a polyester film.

  The present invention relates to a multilayer film in which a silicone resin layer is laminated on at least one surface of a polyester film via a dipentaerythritol alkyl acrylate cured layer, and a method for producing the same.

  Since the multilayer film of the present invention has a dipentaerythritol alkyl acrylate cured layer, the migration of the oligomer contained in the polyester film to the silicone resin layer is suppressed. For example, optical applications such as LCD and PDP Moreover, it can use suitably for the use which dislikes the oligomer derived from PET to the multilayer film surface.

<Polyester film>
The polyester film constituting the multilayer film of the present invention is a known polyester film, which may be any of unstretched, uniaxially stretched or biaxially stretched film, but the biaxially stretched film is in terms of mechanical strength, heat resistance, etc. preferable.

The thickness and surface roughness of the polyester film according to the present invention can be variously selected depending on the application. Usually, the thickness is 3 to 100 μm, preferably 5 to 50 μm.
The polyester film according to the present invention can be produced by a conventionally known method. For example, in the case of a biaxially stretched film, the raw material polyester is melted and cast on a cooling drum to form an unstretched film, and then the unstretched film is converted into a secondary transition point (Tg) of the polyester at −10 ° C. At the above temperature, the film is usually stretched 2 to 7 times in the machine direction, and is first made into a uniaxially stretched film. This uniaxially stretched film is further stretched usually 2 to 9 times in the transverse direction at 80 to 140 ° C. can do. In that case, the film excellent in heat-resistant shrinkage is obtained by heat-processing at 130-250 degreeC further. In addition, the biaxially stretched film may be further stretched in the machine direction and / or the transverse direction as necessary before heat treatment.

The polyester as a raw material for the polyester film according to the present invention comprises a dicarboxylic acid component and a glycol component (dihydroxy compound component).
Examples of the dicarboxylic acid component which is one of the components of the polyester include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, hexahydroterephthalic acid, 4,4′-diphenyldicarboxylic acid, etc. 2,6-naphthalenedicarboxylic acid is preferred because it is excellent in the mechanical properties and thermal properties of the polyester film. Moreover, 1 type, or 2 or more types may be sufficient as this dicarboxylic acid component.

  Examples of the glycol component that is another component of the polyester include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol, polyethylene glycol, and polytetramethylene glycol. , Dipropylene glycol, triethylene glycol, bisphenol and the like are exemplified. Among them, ethylene glycol is preferable because it is excellent in mechanical properties, thermal properties and the like of the polyester film. Moreover, 1 type, or 2 or more types may be sufficient as this glycol component.

  Examples of these polyesters include polyethylene terephthalate and polyethylene-2,6-naphthalate. Such polyethylene terephthalate or polyethylene-2,6-naphthalate may be a polyester obtained by copolymerization of the above dicarboxylic acid component or glycol component, and the polyester substantially comprises trifunctional or higher polycarboxylic acid component or polyol component. It may be a polyester copolymerized in a small amount in a range that is in the form of, for example, 5 mol% or less.

These polyesters can be produced by a conventionally known method, and the average molecular weight is preferably 10,000 or more because the mechanical properties of the film are improved.
These polyesters can contain organic or inorganic fine particles as a lubricant in a blending ratio of, for example, 0.001 to 5% by weight in order to improve the slipperiness of the film.

  As such fine particles, calcium carbonate, calcium oxide, titanium oxide, graphite, kaolin, silica, alumina, silicon oxide, zinc oxide, carbon black, silicon carbide, tin oxide, acrylic resin particles, crosslinked polystyrene resin particles, melamine resin particles Cross-linked silicone resin particles and the like can be mentioned as suitable examples.

  In addition, as other compounding agents, antistatic agents, antioxidants, organic lubricants, catalysts, colorants, pigments, fluorescent brighteners, plasticizers, crosslinking agents, lubricants, UV absorbers, and other resins are required. It can be added depending on.

<Dipentaerythritol alkyl acrylate>
The dipentaerythritol alkyl acrylate forming the dipentaerythritol alkyl acrylate cured layer of the multilayer film of the present invention is one of polyol acrylate compounds and is an ester of a polyhydric alcohol and an unsaturated carboxylic acid having an acrylic group. Among these dipentaerythritol alkyl acrylates, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate are preferable.

<Silicone resin>
The silicone resin that forms the silicone resin layer of the multilayer film of the present invention is selected according to various uses. For example, it can be obtained by curing reaction with heat, ultraviolet rays, electron beams, etc. in consideration of adhesion to the release film substrate, stability of peel strength during the release process, and non-migration of the silicone resin component A silicone resin is desirable. In addition, an addition reaction of an organopolysiloxane having at least two alkenyl groups directly bonded to silicon atoms in one molecule and an organohydropolyene polysiloxane having at least two hydrogen atoms directly bonded to silicon atoms in one molecule The obtained silicone resin is desirable.

  Specific examples of organopolysiloxane include dimethylalkenylsiloxy group end-capped dimethylpolysiloxane, trimethylsiloxy group end-capped methylalkenylsiloxane / dimethylsiloxane copolymer, silanol group end-capped methylalkenylsiloxane / dimethylsiloxane copolymer, Examples thereof include dimethylalkenylsiloxy group end-capped methylphenylsiloxane / dimethylsiloxane copolymer, dimethylalkenylsiloxy group endcapped diphenylsiloxane / dimethylsiloxane copolymer, and the like.

  Specific examples of the organohydrodiene polysiloxane include dimethylhydrosiloxy group end-capped dimethylsiloxane / methylhydrodiene siloxane copolymer, trimethylsiloxy group end-capped dimethylsiloxane / methylhydrodiene siloxane copolymer, dimethyl Examples thereof include phenylsiloxy group-end-capped dimethylsiloxane / methylhydrodienesiloxane copolymer, trimethylsiloxy group-end-capped methylhydropolyenepolysiloxane, and cyclic methylhydrodienepolysiloxane.

In forming the silicone resin, the amount of this component used is usually 0.2 to 40 parts by weight of the organohydropolyene component relative to 100 parts by weight of the organopolysiloxane component. In order to accelerate the addition reaction by heat, a platinum catalyst etc. coexist, and in order to promote the addition reaction by ultraviolet light, a photopolymerization initiator etc. coexist to achieve the curing reaction relatively quickly. The desired silicone resin layer can be formed.
Within the scope of the present invention, the silicone resin may further contain a known reaction control agent, an inorganic filler such as silica, or a pigment as necessary.

<Multilayer film>
The multilayer film of the present invention is formed by laminating a silicone resin layer on at least one surface of a polyester film via a dipentaerythritol alkyl acrylate cured layer.

  The multilayer film of the present invention can suppress the transition to the silicone resin layer such as an oligomer contained in the polyester film by passing through the dipentaerythritol alkyl acrylate cured layer.

  Instead of dipentaerythritol alkyl acrylate, bisphenol A type epoxy acrylate compound, polyester acrylate compound, ditrimethylolpropane tetraacrylate, glycerol diepoxy (meth) acrylate, glycerol triepoxy (meth) acrylate, 1,6- When hexanediol diepoxy (meth) acrylate, neopentyl glycol diepoxy (meth) acrylate, rosin epoxy acrylate, or the like is used, the effect of suppressing migration of the oligomer to the silicone resin layer is insufficient.

  In the multilayer film of the present invention, the polyester film has a thickness of usually 3 to 100 μm, preferably 5 to 50 μm, and the dipentaerythritol alkyl acrylate cured layer has a thickness of usually 0.1 to 5 μm, preferably 0.00. The thickness of the 1-2 μm silicone resin layer is usually 0.01 to 5 μm, preferably 0.05 to 1 μm.

<Method for producing multilayer film>
In the multilayer film of the present invention, dipentaerythritol alkyl acrylate is applied to at least one surface of a polyester film, and then cured with active energy rays to form a dipentaerythritol alkyl acrylate cured layer. After applying a silicone resin on the acrylate cured layer, it can be efficiently prepared by curing.

<Formation of cured layer of dipentaerythritol alkyl acrylate>
The dipentaerythritol alkyl acrylate cured layer is formed by applying dipentaerythritol alkyl acrylate on a polyester film and curing it with active energy rays.

The dipentaerythritol alkyl acrylate may be blended with known inorganic fine particles such as silica as required within the scope of the present invention.
Dipentaerythritol alkyl acrylate is usually used after diluting with an organic solvent. The organic solvent is not particularly limited, but aromatic hydrocarbons such as benzene and toluene, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol and 2-ethoxyethanol, ketones such as methyl ethyl ketone, dipropyl ketone and diisobutyl ketone, These mixed solvents are exemplified.

  As a method of applying a solution of an organic solvent of dipentaerythritol alkyl acrylate to the surface of a polyester film, for example, an air knife coater, a direct gravure coater, a gravure offset, an arc gravure coater, a gravure coater such as a gravure reverse and jet nozzle method, Various known coating machines such as reverse roll coaters such as top feed reverse coater, bottom feed reverse coater and nozzle feed reverse coater, 5-roll coater, lip coater, bar coater, bar reverse coater and die coater may be used. it can.

  As for the application of the dipentaerythritol alkyl acrylate solution, it is desirable to adjust the concentration so that the thickness after application is usually 0.1 to 5 μm. If thickness is 0.1 micrometer or more, transfer to the silicone resin layer of the hardening inhibitor contained in a polyester film can be suppressed.

  It is desirable that a photopolymerization initiator is blended in the dipentaerythritol alkyl acrylate solution. Photopolymerization initiators include acetophenone, acetophenone benzyl ketal, anthraquinone, 1- (4-isopropylphenyl-2-hydroxy-2-methylpropan-1-one, carbazole, xanthone, 4-chlorobenzophenone, 4, 4'-diaminobenzophenone, 1,1-dimethoxydeoxybenzoin, 3,3'-dimethyl-4-methoxybenzophenone, thioxanthone, 2,2-dimethoxy-2-phenylacetophenone, 1- (4-dodecylphenyl) -2- Hydroxy-2-methylpropan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, triphenylamine, 2,4,6-trimethylbenzoyldiphenylphosphine Oxide, 1-hydroxycyclohexyl Phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, fluorenone, fluorene, benzaldehyde, benzoin ethyl ether, benzoisopropyl ether, benzophenone, Michler ketone, 3-methylacetophenone, 3,3 ′, 4,4 '-Tetra-tert-butylperoxycarbonylbenzophenone (BTTB), 2- (dimethylamino) -1- [4- (morpholinyl) phenyl] -2-phenylmethyl) -1-butanone, 4-benzoyl-4 Examples include '-methyldiphenyl sulfide, benzyl and the like.

The photopolymerization initiator may be used in combination with a dye sensitizer. Examples of the dye sensitizer include xanthene, thioxanthene, coumarin, and ketocoumarin.
Examples of the combination of the photopolymerization initiator and the dye sensitizer include a combination of BTTB and xanthene, a combination of BTTB and thioxanthene, a combination of BTTB and coumarin, and a combination of BTTB and ketocoumarin.

  Examples of commercially available photopolymerization initiators include IRGACURE 651, IRGACURE 184, IRGACURE 500, IRGACURE 1000, IRGACURE 2959, DAROCUR 1173 sold by Ciba Specialty Chemicals, respectively, and ESACURE ONE sold by Lamberti, Examples include ESACURE KIP150.

  As for these photopolymerization initiators and dye sensitizers, it is desirable to avoid a substance that inhibits curing when the silicone resin layer is formed. For example, when using a platinum catalyst, it is desirable to avoid compounds containing nitrogen, phosphorus, sulfur, lead, tin, and the like.

  When using a photoinitiator, it is about 0.1-10 weight part normally with respect to 100 weight part of polymeric compounds used. If the amount used is too small, the curing rate tends not to increase as compared with the case where no photopolymerization initiator is used.

  After applying dipentaerythritol alkyl acrylate, it is dried as necessary, and then the formed coating film is irradiated with active energy rays to obtain a polyester film in which a cured layer of dipentaerythritol alkyl acrylate is formed. it can.

Examples of the activation energy rays include electron beams, ultraviolet rays, and visible rays, and can be appropriately selected according to the type of activation energy rays and curable compounds to be used.
The intensity | strength and irradiation time of the activation energy ray to irradiate can be suitably selected according to the kind of curable compound to be used, the thickness of the coating film containing a curable compound, etc. The activation energy ray may be irradiated in an inert gas atmosphere, and examples of the inert gas include nitrogen gas and argon gas.

  The film thickness of the dipentaerythritol alkyl acrylate cured layer is usually 0.1 to 5 μm, preferably 0.1 to 2 μm. When the thickness of the cured layer is increased, residual stress may be generated in the dipentaerythritol alkyl acrylate cured layer due to a crosslinking reaction of dipentaerythritol alkyl acrylate. For this reason, the dipentaerythritol alkyl acrylate cured layer tends to curl due to its shrinkage, and the handling property tends to be unfavorable. Furthermore, there is a possibility that the adhesiveness between the base polyester film and the dipentaerythritol alkyl acrylate cured layer is lowered.

  Moreover, in order to improve the adhesiveness of the dipentaerythritol alkylacrylate cured layer to the polyester film, an adhesive layer may be provided on the surface of the polyester film, and a dipentaerythritol alkylacrylate cured layer may be provided on the adhesive layer.

<< Formation of silicone resin layer >>
After forming the dipentaerythritol alkyl acrylate cured layer, a silicone resin layer is formed.

  The silicone resin layer is formed by various conventionally known methods. For example, in the case of coating a thermosetting silicone resin having a solvent type and an emulsion type, the solution or aqueous dispersion of the coated silicone resin is transferred to a drying step, and the drying temperature at that time is 50 to It may be in a range of 120 ° C, and a range of 60 to 110 ° C is preferable. If the drying temperature is less than 50 ° C., the thermosetting time becomes longer and the productivity is lowered, which is not preferable. On the other hand, if it exceeds 120 ° C., wrinkles occur in the film, which is not preferable.

  On the other hand, in the case of coating an ultraviolet or electron beam curable type silicone resin having a solvent type and an emulsion type, since the ultraviolet ray or electron beam irradiation step is provided after the drying step, the drying is performed in the solvent. Alternatively, it may be carried out at the minimum temperature necessary for drying and removing water.

  In order to improve the adhesion of silicone resin to polyester film, surface activation treatment such as corona discharge treatment, flame treatment, ozone treatment on the surface of the cured layer of dipentaerythritol alkyl acrylate of polyester film before coating with silicone resin Alternatively, an anchor coating treatment using an anchor treatment agent may be performed.

  Furthermore, if necessary, another polyester film is laminated on the surface of the multilayer film (the side opposite to the silicone resin layer) via an anchor treatment agent or an adhesive, or a printing layer or an antistatic agent. It can be used by providing a layer.

  In addition, when a dipentaerythritol alkyl acrylate hardened layer and a silicone resin layer are provided only on one side, another resin layer may be provided on the opposite side. As such another resin layer, there is the above-mentioned dipentaerythritol alkyl acrylate cured layer.

  The silicone resin layer can be provided by a coating method. In that case, any one of a solvent type, an emulsion type, and a solventless type can be used in terms of form. However, in order to uniformly form a thin film of a silicone resin, a solvent type or an emulsion type is desirable, and a solvent type or an emulsion type is also desirable from the viewpoint of pot life of a curable silicone resin component.

  The method of coating the silicone resin on the polyester film depends on whether it is a solvent type, an emulsion type, or a solvent-free form. For example, a roll coating method, a screen printing method, a bar coating method, a spray coating method, etc. Any method can be adopted, and the roll coating method is suitable as a method for forming a uniform film at a high speed.

  The thickness of the silicone resin layer is usually from 0.01 to 5 μm, preferably from 0.05 to 1 μm. For example, within this range, the performance can be adjusted in terms of adhesion to the release film substrate, stability of the peel strength during the release process, and non-migration of the silicone resin component. As a result, the desired excellent releasability can be obtained.

EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.
The physical property values and the like in Examples and Comparative Examples were measured by the following methods.

(1) Preparation of sample Each of the following polymerizable compounds and initiators for each sample was prepared as a solution of methyl ethyl ketone, each having a width of 210 mm × length of 290 mm (A4 size), a film thickness of 38 μm, and a surface roughness (center plane). On one side of a PET film having an average roughness SRa) of 0.027 μm, Mayaba No. 4 was dried in an oven at 70 ° C. for 20 seconds, and further cured by ultraviolet (UV) irradiation (120 W × 8 m / min) to obtain a coated film.

Sample 1
(Dipentaerythritol alkyl acrylate): Example 1
Polymerizable compound: Dipentaerythritol hexaacrylate compound (CH ₂ ═CHCOOCH ₂ ) ₃ CCH ₂ 0CH ₂ C (CH ₂ ═CHCOOCH ₂ ) ₃
(CH ₂ = CHCOOCH ₂ ) ₃ CCH ₂ 0CH ₂ C (CH ₂ = CHCOOCH ₂ ) ₂ OH
(* Note 1) (Concentration in solution: 2% by mass)
Initiator: Bifunctional alpha hydroxy ketone (* Note 2) (concentration in solution: 0.3% by mass)
* Note 1: Aronix M-406 (manufactured by Toa Gosei Co., Ltd.)
* Note 2: ESACURE ONE (Lamberti)

Sample 2
(Glycerin diepoxy (meth) acrylate): Comparative Example 1
Mixture of glycerin diepoxy acrylate Glycerin diepoxy acrylate (* Note 3) (concentration in solution 0.7 mass%)
Rosin epoxy acrylate (* Note 4) (concentration in solution 0.6% by mass)
Hexaethylene diacrylate (* Note 5) (concentration in solution: 0.7% by mass)
Initiator: Hydroxycyclohexyl ketone (* Note 6) (concentration in solution: 0.2% by mass)
* Note 3: 80MFA (manufactured by Kyoeisha Chemical Co., Ltd.)
* Note 4: Beam Set 101 (Arakawa Chemical Industries)
* Note 5: New Frontier PE-300 (Daiichi Kogyo Seiyaku Co., Ltd.)
* Note 6: Irgacure 184 (Ciba Specialty Chemicals)

Sample 3
(Bisphenol A type epoxy acrylate compound): Comparative Example 2
Polymerizable compound: bisphenol A type epoxy acrylate compound _{CH = CHCOOCH 2 CH (OH)} CH 2 0-φ-C (CH 3) 2 -φ-OCH 2 CH (OH) CH 2 OOCCH = CH 2 (* Note 7 (Concentration in solution: 15% by mass)
Initiator: Bifunctional alpha hydroxy ketone (* Note 2) (concentration in solution: 0.3% by mass)
* Note 7: NK Oligo EA-1020 (Shin Nakamura Chemical Co., Ltd., molecular weight 540)

Sample 4
(Trimethylolpropane tetraacrylate compound): Comparative Example 3
Trimethylolpropane tetraacrylate (* Note 8) (concentration in solution of 2% by mass)
Initiator: Bifunctional alpha hydroxy ketone (* Note 2) (concentration in solution: 0.3% by mass)
* Note 8: AD-TMP (manufactured by Shin-Nakamura Chemical Co., Ltd.)

Sample 5
(Pentaerythritol triacrylate compound): Comparative Example 4
Pentaerythritol triacrylate (* Note 9) (concentration in solution: 2% by mass)
Initiator: Bifunctional alpha hydroxy ketone (* Note 2) (concentration in solution: 0.3% by mass)
* Note 9: A-TMM-3LM-N (manufactured by Shin-Nakamura Chemical Co., Ltd.)

Sample 6
(Tricyclodecane dimethanol diacrylate compound): Comparative Example 5
Tricyclodecane dimethanol diacrylate (* Note 10) (concentration in solution of 2% by mass)
Initiator: Bifunctional alpha hydroxy ketone (* Note 2) (concentration in solution: 0.3% by mass)
* Note 10: A-DCP (manufactured by Shin-Nakamura Chemical Co., Ltd.)

Next, a solution of the following silicone / catalyst mixed solvent of toluene / methyl ethyl ketone (70/30 volume ratio) was prepared. No. 4 was used to apply silicone (: KS-847 (manufactured by Shin-Etsu Chemical Co., Ltd.)) and catalyst (PL-50T (manufactured by Shin-Etsu Chemical Co., Ltd.)), dried in an oven at 100 ° C. for 20 seconds, and 0.1 g / A coating film of m ² was formed to prepare a multilayer film sample.

(2) Observation of oligomers with a scanning electron microscope The prepared samples were heat-treated in an oven at 160 ° C. for 10 minutes and 30 minutes, then taken out and cooled, and then Au was sputtered onto the release layer surface of each sample. Observing a 200 μm × 200 μm field of view with a scanning electron microscope at a magnification of 500 times, and extruding the oligomer onto the surface and removing the oligomer crystal (hexagonal columnar crystal) from the release film The oligomer was not present on the surface of the layer. The apparatus used was JSM-5600 manufactured by JEOL Ltd.

Example 1 and Comparative Examples 1-5
Using the above samples 1 to 6, the above was measured.
The results are shown in Table 1.

実施例１の多層フィルム（サンプル１）は、熱処理を施しても離型層表面へのオリゴマー析出は観察されなかった。比較例１〜５の多層フィルム（サンプル２〜６）は、離型層表面への析出が観察され、オリゴマー析出抑制能は不十分なものであった。

In the multilayer film of Example 1 (Sample 1), oligomer deposition on the surface of the release layer was not observed even when heat treatment was performed. In the multilayer films of Comparative Examples 1 to 5 (Samples 2 to 6), precipitation on the surface of the release layer was observed, and the oligomer precipitation suppressing ability was insufficient.

  The multilayer film of the present invention can be suitably used as a release film for a polarizing plate, for example.

Claims (3)

On at least one surface of the polyester film, through a dipentaerythritol acrylate cured layer dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate containing no antistatic agent, an alkenyl group directly attached to a silicon atom in a molecule A silicone resin layer obtained by an addition reaction of an organopolysiloxane having at least two hydrogen atoms and an organohydropolyene polysiloxane having at least two hydrogen atoms directly bonded to silicon atoms in one molecule is laminated. A multilayer film.   The multilayer film according to claim 1, which is a polyester film having a thickness of 5 to 50 µm, a cured layer of dipentaerythritol alkyl acrylate having a thickness of 0.1 to 5 µm, and a silicone resin layer having a thickness of 0.01 to 5 µm. . On at least one surface of the polyester film, after dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate containing no antistatic agent is applied, after forming a dipentaerythritol acrylate cured layer is cured by active energy ray Next, an organopolysiloxane having at least two alkenyl groups directly bonded to silicon atoms in one molecule and at least two hydrogen atoms directly bonded to silicon atoms in one molecule on the dipentaerythritol alkyl acrylate cured layer. A method for producing a multilayer film, comprising: applying a silicone resin comprising an organohydrodiene polysiloxane, and then curing the silicone resin by heating.