JP4558560B2 - Multilayer film - Google Patents

Description

  The present invention relates to a multilayer film excellent in surface smoothness.

  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 the production of multilayer ceramic capacitors.

  With regard to multilayer ceramic capacitors, electronic devices have recently been downsized and improved in performance, and it is required to further smooth the release film used as a process film. However, since the polyester film is handled in the form of a roll obtained by extrusion, there is a limit to improving the smoothness of the polyester film itself.

  In addition, in a release film in which a silicone resin is laminated on one side of a polyester film, a primer in which a silane coupling agent is previously crosslinked on the surface of the polyester film in order to improve the adhesion between the silicone resin and the base polyester film. It is known to provide a layer. (JP-A-1-5838)

  In order to improve the antistatic effect of the polyester film, it is known that a silicone resin layer is laminated after previously applying a coating solution made of a polymer having a pyrroldium ring in the main chain to the polyester film. (JP-A-1-171940) For the purpose of further improving the antistatic performance, an undercoat layer using a water-soluble organosilane compound is formed on at least one surface of a polyester film, and a metal compound and a charge transfer complex are formed thereon. It is also known to form an antistatic layer using an alkoxysilane and / or a partial hydrolyzate thereof, and a release layer using a curable silicone thereon. (Japanese Patent Laid-Open No. 5-25302)

  Similarly, it is known that an antistatic layer composed of a binder resin such as a polyvinyl resin and an antistatic agent is laminated on at least one surface of a polyester film, and a curable silicone resin layer is laminated thereon. (Japanese Patent Laid-Open No. 2002-192661)

JP-A-1-5838 JP-A-1-171940 JP-A-5-25302 JP 2002-192661

  A multilayer film in which a cured resin layer (B) made of a photocationically polymerizable substance and a silicone resin layer (C) are laminated in this order on at least one surface of a polyester film (A). An object of the present invention is to improve the smoothness of the surface of a polyester film having a silicone resin layer laminated on the surface thereof.

  That is, the present invention relates to a multilayer film in which a cured resin layer (B) made of a photocationically polymerizable substance and a silicone resin layer (C) are laminated in this order on at least one surface of a polyester film (A).

  According to the present invention, the smoothness of the surface of the silicone resin layer laminated on the polyester film can be improved by simple means. Furthermore, according to the present invention, even if the polyester film to be used does not have a high degree of smoothness, the surface of the applied silicone resin layer can be a surface having a very high degree of smoothness. Therefore, the laminated film of the present invention can be provided at economically advantageous costs for various uses that require a high degree of smoothness.

  In the present invention, the smoothness of the surface is improved by laminating a specific cured resin layer (B) and further a corn resin layer (C) on the polyester film (A).

Polyester film The polyester film used in the present invention is a known polyester film, and may be an unstretched, uniaxially stretched or biaxially stretched film, but a biaxially stretched film is preferred in terms of mechanical strength, heat resistance and the like. .
The thickness and surface roughness of the polyester film used in the present invention can be variously selected depending on applications. Usually, the thickness is 3 to 100 μm, preferably 5 to 50 μm. Even a thin film can be smoothed by the present invention. In the present invention, even if the surface roughness SRa is about 0.05 μm, it can be smoothed by the present invention.

  These polyester films 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.

The polyester film can be produced by a conventionally known method. For example, in the biaxially stretched film, the above polyester is melted and cast on a cooling drum to form an unstretched film, and then the unstretched film is subjected to a secondary transition point (Tg) of the polyester at a temperature of −10 ° C. or higher. The film can be stretched 2 to 7 times in the machine direction to form a uniaxially stretched film, and the uniaxially stretched film can be further biaxially stretched 2 to 9 times in the transverse direction at 80 to 140 ° C. to obtain a film.
In that case, it heat-processes 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 area stretch ratio of the biaxially stretched film is preferably 8 times or more, more preferably 9 times or more, and the upper limit of the area stretch ratio is 35 times, especially 30 times, although it depends on the use of the film. Is preferred. The orientation crystallization can be completed by heat treatment after stretching. The thickness of the biaxially laminated stretched film is usually 1 to 300 μm.

Cured resin layer In the present invention, the cured resin layer (B) is preferably formed by irradiating an curable composition comprising a photocationically polymerizable substance with an active energy ray and curing it.

  The photocationic polymerizable substance used is a compound that can be polymerized by cationic polymerization and has at least one photocationically polymerizable functional group in the molecule. The structure may be any of aliphatic, alicyclic, aromatic and the like. Moreover, the form may be any of a monomer, an oligomer, a polymer and the like. Examples of the photocationically polymerizable functional group include an epoxy group, an oxetane group, a vinyl ether group, and an episulfide group. These functional groups may be present at any site in the terminal, side chain, or molecular skeleton of the molecular skeleton constituting the photocationically polymerizable substance.

  The number of photocationically polymerizable functional groups in these photocationically polymerizable substances is preferably 1 or more per molecule, more preferably for the heat resistance of the cured resin layer (B) of the present invention. Two or more.

  The properties of the photocationically polymerizable substance can be used without any particular limitation.

  Preferable examples of the photocationically polymerizable substance include at least one epoxy group-containing compound, oxetane group-containing compound, and vinyl ether group-containing compound that can be polymerized by cationic polymerization in the molecule.

Epoxy group-containing compound Examples of the epoxy group-containing compound include the following compounds.
There are bisphenol A type epoxy compounds obtained by reacting bisphenol A and epichlorohydrin in the presence of alkali, bisphenol F type epoxy compounds, bisphenol AD type epoxy compounds, and the like. Examples of the novolak type epoxy compound include a phenol novolak type epoxy compound and a cresol novolak type epoxy compound. In addition, there are trisphenol methane triglycidyl ether type epoxy compounds and their hydrogenated products and brominated products.
As specific examples, Epicoat 825, Epicoat 827, Epicoat 828, Epicoat 828EL, Epicoat 828US (above Japan Epoxy Resin), KRM-2400, KRM-2405, KRM-2410, KRM-2510 (above Asahi Denka Kogyo Co., Ltd.) ), Epolite 4000, Epolite 3002 (the above are Kyoeisha Chemical Co., Ltd.) and the like bisphenol A type epoxy compounds.

Examples of the alicyclic epoxy compound include compounds obtained by oxidizing a double bond with peracetic acid in a compound containing a cyclohexene ring. Specifically, the following compounds are exemplified.
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate,
3,4-epoxy-2-methylcyclohexylmethyl-3,4-epoxy-2-methylcyclohexanecarboxylate,
Bis (3,4-epoxycyclohexyl) adipate,
Bis (3,4-epoxycyclohexylmethyl) adipate,
Bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate,
2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexanone-meta-dioxane,
And bis (2,3-epoxycyclopentyl) ether.
These include Celoxide 2021, Celoxide 2021A, Celoxide 2021P, Celoxide 2081 (manufactured by Daicel Chemical Industries), KRM-2110, KRM-2199 (manufactured by Asahi Denka Kogyo Co., Ltd.), and the like.

In addition, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl Examples include ethers, polyglycidyl ethers of long-chain polyols including polyoxyalkylene glycols containing 2 to 9 (preferably 2 to 4) carbon atoms alkylene groups, polytetramethylene ether glycols, and the like.

 Examples of the glycidyl ester type epoxy compounds include phthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, diglycidyl-p-oxybenzoic acid, salicylic acid glycidyl ether-glycidyl ester, dimer acid glycidyl ester, etc. As well as these hydrogenated products.

Examples of glycidylamine type epoxy resins include triglycidyl isocyanurate, N, N′-diglycidyl derivatives of cyclic alkylene urea, N, N, O-triglycidyl derivatives of p-aminophenol, and N, N, O of m-aminophenol. -Triglycidyl derivatives and the like and hydrogenated products thereof.
These epoxy group-containing compounds may be used alone or in combination of two or more.
Among these epoxy group-containing compounds, glycidyl group-containing epoxy compounds and alicyclic epoxy compounds are particularly suitable.

Oxetane group-containing compounds Oxetane group-containing compounds include 1,4-bis [{(3-ethyl-3-oxetanyl) methoxy} methyl] benzene, 3-ethyl-3-[(2-ethylhexyloxy). ) Methyl] oxetane, bis {[1-ethyl (3-oxetanyl)] methyl} ether, 3-ethyl-3-hydroxyethyloxetane,
3-ethyl-3- (phenoxymethyl) oxetane, 2-hydroxymethyl-2-methyloxetane, 2-hydroxymethyl-2-ethyloxetane, 2-hydroxymethyl-2-propyloxetane, 2-hydroxymethyl-2-butyl There is oxetane.

Vinyl ether group-containing compounds The vinyl ether group-containing compounds include ethylene glycol monovinyl ether, ethylene glycol divinyl ether, propylene glycol monovinyl ether, propylene glycol divinyl ether, neopentyl glycol monovinyl ether, neopentyl glycol divinyl ether, glycerol divinyl ether. Glycerol trivinyl ether, trimethylolpropane monovinyl ether, trimethylolpropane divinyl ether, trimethylolpropane trivinyl ether, diglycerol trivinyl ether, sorbitol tetravinyl ether, allyl vinyl ether, 4-vinyl ether styrene, hydroquinone divinyl ether, phenyl vinyl ether, etc. Alkyl vinyl ethers such as t- butyl ether; Lumpur vinyl ether monomers obtained by modifying the hydroxyl group in ether, and the like oligomers.

Photocationic polymerization initiator In the present invention, a cationic polymerization initiator is used together with a photocationically polymerizable substance.
Cationic polymerization initiators include, for example, onium salts such as aryldiazonium salts, aryliodonium salts, arylhalonium salts, and arylsulfonium salts, organometallic complexes such as iron-allene complexes, titanocene complexes, and arylsilanol-aluminum complexes. Is mentioned.
These may be used independently and 2 or more types may be used together.

  Commercially available products include PCI-220, PCI-620 (manufactured by Nippon Kayaku Co., Ltd.), UVI 6990 (manufactured by Union Carbide), SP-150, SP-152, SP-170, SP-172 (and above Asahi Denka Kogyo Co., Ltd.) Manufactured), Uvacure 1590, 1591 (manufactured by Daicel UCB), Sun-Aid SI-110, SI-180, SI-100L, SI-80L, SI60L (manufactured by Sanshin Chemical).

The addition amount of a photocationic polymerization initiator is not specifically limited. For example, it is usual to use about 0.1 to 20 parts by weight with respect to 100 parts by weight of the photocationically polymerizable substance used.
The photosensitizer photocationic polymerization initiator is desirably used in combination with a photosensitizer.
Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfurized compounds, redox compounds, azo and diazo compounds, halogen compounds, and photoreductive dyes. Specific photosensitizers include, for example, benzoin methyl ether, benzoin isopropyl ether, benzoin derivatives such as α, α-dimethoxy-α-phenylacetophenone, benzophenone, 2,4-dichlorobenzophenone, o-benzoylbenzoic acid. Methyl, 4,4′-bis (dimethylamino) benzophenone, benzophenone derivatives such as 4,4′-bis (dimethylamino) benzophenone, thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone, 2-chloroanthraquinone Anthraquinone derivatives such as 2-methylanthraquinone, acridone derivatives such as N-methylacridone and N-butylacridone, α, α-diethoxyacetophenone, benzyl, fluorenone, xanthone, Sulfonyl compounds, and halogen compounds. However, it is not limited to these. These may be used alone or in combination. The photosensitizer is preferably added in an amount of about 0.1 to 20 parts by weight with respect to 100 parts by weight of the photocationically polymerizable substance.

  As for these photopolymerization initiators and photosensitizers, 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.

Formation of cured resin layer (B) The cured resin layer (B) is formed by applying a curable composition comprising a cationic photopolymerizable substance to at least one surface of the polyester film (A) and irradiating it with active energy rays. It is desirable to do.
In addition to the cationic photopolymerizable substance, the curable composition usually contains a photopolymerization initiator and an organic solvent, and further contains a photosensitizer as necessary.
As the organic solvent, a solvent having good compatibility with the photocationic polymerization initiator is preferably used.

  Furthermore, well-known inorganic fine particles, such as a silica, can also be mix | blended with a curable composition as needed within the scope of the present invention.

  Examples of the method for applying the solution of the curable composition to the surface of the polyester film include an air knife coater, a direct gravure coater, a gravure offset, an arc gravure coater, a gravure reverse coater, a gravure reverse coater, a top feed, and the like. Various known coating machines such as a reverse roll coater such as a reverse coater, a bottom feed reverse coater and a nozzle feed reverse coater, a 5-roll coater, a lip coater, a bar coater, a bar reverse coater and a die coater can be used.

  It is desirable to apply these polymerizable compound solutions by adjusting the concentration so that the thickness after application is 0.1 to 5 μm.

  After apply | coating a curable composition, it dries as needed, Then, active energy is irradiated to the formed coating film, and a cured resin layer (B) is formed.

Examples of the active energy rays include electron beams, ultraviolet rays, visible rays, X rays, and γ rays, and can be appropriately selected according to the type of active energy rays and curable compounds to be used. Among them, ultraviolet rays that are easy to handle and can obtain relatively high energy are preferable.
As a light source for irradiating ultraviolet rays, carbon arc, mercury vapor arc, fluorescent lamp, argon glow lamp, halogen lamp, incandescent lamp, low pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, metal halide lamp, flash UV lamp, deep UV lamp, xenon There are lamps and tungsten filament lamps.

The intensity | strength and irradiation time of the active 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 active energy ray may be irradiated in an inert gas atmosphere, and examples of the inert gas include nitrogen gas and argon gas.
The amount of active energy ray irradiation can be appropriately determined according to the type and amount of each component of the curable composition, the thickness to be applied, the light irradiation source, and the like.

  The thickness of the cured resin layer (B) is usually from 0.01 to 5 μm, and particularly preferably from 0.01 to 2 μm. When the thickness of the cured resin layer is increased, residual stress tends to occur in the cured resin layer during polymerization of the cured resin, resulting in a decrease in adhesion between the base polyester film (A) and the cured resin layer (B). There is a fear of curling.

Moreover, in order to improve the adhesiveness of the cured resin layer (B) to the polyester film (A), an adhesive layer is provided on the surface of the polyester film (A), and the cured resin layer (B) is provided on the adhesive layer. May be.
Examples of such adhesion improvers include silane coupling agents, titanium coupling agents, aluminum coupling agents, and the like. These may be used alone or in combination of two or more.

Silicone resin layer (C)
A silicone resin layer (C) is continuously laminated on the cured resin layer (B).

  The silicone resin used 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 between 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.

  Examples of specific organohydrodiene polysiloxanes include dimethylhydrodisiloxy 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 layer (C), the amount of this component used is usually 0.2 to 40 parts by weight of the organohydropolysiloxane component relative to 100 parts by weight of the organopolysiloxane component. In order to promote the addition reaction by heat, these are made to coexist with a platinum catalyst, and in order to promote the addition reaction by ultraviolet rays, a photopolymerization initiator is made to coexist relatively quickly. A curing reaction can be achieved, and a 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.

The thickness of the silicone resin layer (C) is usually 0.01 to 5 μm, preferably 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. Thus, the desired excellent release film can be obtained.

  The silicone resin layer (C) 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 cured resin layer (B) differs depending 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. Any method such as a spray coating method can be employed. Above all, the roll coating method is suitable as a method for forming a uniform film at a high speed.

  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 process, and the drying temperature at that time is 50 to 120 ° C. The range of 60-110 degreeC 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 the silicone resin to the cured resin layer (B), the surface of the cured resin layer (B) of the polyester film is subjected to corona discharge treatment, flame treatment, ozone treatment, etc. before coating with the silicone resin. An activation treatment or 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, as for the release film which provided the cured resin layer (B) only on the single side | surface, the polyester film surface is exposed on the opposite surface side, and these may be wound up depending on a process process. If the laminate is uncured or tacky, they may transfer to the exposed polyester film surface and contaminate the surface.
It is preferable to provide a resin having a small surface energy as a contamination-preventing layer on the polyester film surface so that such contamination can be eliminated or easily removed even if it is contaminated. For example, a silicone resin is preferable, and those having methylpolysiloxane or phenylmethylpolysiloxane as a main component are particularly preferable.

(Example)
EXAMPLES Next, although this invention is demonstrated through an Example, this invention is not limited at all by these Examples.

(1) Preparation of sample The polymerizable compound and initiator of each of the following samples were each 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 (central surface average) On one side of a PET film having a roughness SRa) of 0.028 μm, a Mayba-No. 3 was dried in an oven at 70 ° C. for 20 seconds, and further cured by ultraviolet (UV) irradiation (120 W × 8 m / min × 4 times irradiation) to obtain a coated film.

Sample 1
Adekaoptomer KRM-2110 (Asahi Denka Kogyo Co., Ltd.) Alicyclic epoxy compound 1500 parts by mass SP-170 (Asahi Denka Kogyo Co., Ltd.) Photocationic polymerization initiator 75 parts by mass Methyl ethyl ketone Organic solvent 8425 parts by mass

Sample 2
Adeka optomer KRM-2405 (manufactured by Asahi Denka Kogyo Co., Ltd.) Epoxy compound (Note 1) 1500 parts by mass SP-170 (manufactured by Asahi Denka Kogyo Co., Ltd.) Photocationic polymerization initiator 75 parts by mass Organic solvent 8425 parts by mass Note 1 : Diglycidyl ether-modified product of 2,2-bis (4-hydroxyphenyl) propane with epichlorohydrin or 2-methylepichlorohydrin

Sample 3
Adekaoptomer KRM-2604 (Asahi Denka Kogyo Co., Ltd.) Epoxy Compound (Note 2) 1500 parts by mass SP-170 (Asahi Denka Kogyo Co., Ltd.) Photocationic polymerization initiator 75 parts by mass Methyl ethyl ketone Organic solvent 8425 parts by mass Note 2: Phenol Modified glycidyl ether of novolak type epoxy compound phenol / formaldehyde polycondensate or alkyl (C = 1-9) phenol / formaldehyde polycondensate with epichlorohydrin or 2-methylepichlorohydrin

Next, a solution of the following silicone / catalyst mixed solvent of toluene / methyl ethyl ketone (70/30 volume ratio) was prepared. 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.)), and dried in an oven at 100 ° C. for 20 seconds. A coating film of 0.1 g / m ² was formed and aged by tens of hours at 40 ° C. to prepare a sample.

(2) Peeling force [N / 50mm]
Each of the above samples was placed on a horizontal table with the coating film facing upward, and an adhesive tape “No. 31B” (manufactured by Nitto Denko Corporation) was attached to the coating film side to measure 200 mm × 50 mm. It was cut into a size, and a load was further applied from the top of the adhesive tape to 20 g / cm ² and aging was carried out at 70 ° C. for 20 hours.
Thereafter, 180 ° peeling was performed at a tensile speed of 300 mm / min with a tensile tester, and an average peeling load in a region where peeling was stable was obtained as a peeling force.

(3) Residual adhesion rate [%]:
Each of the above samples was placed on a horizontal table with the coating film facing upward, and an adhesive tape “No. 31B” (manufactured by Nitto Denko Corporation) was attached to the coating film side to measure 200 mm × 50 mm. It was cut into a size, and a load was further applied from the top of the adhesive tape to 20 g / cm ² and aging was carried out at 70 ° C. for 20 hours. Thereafter, the release film is peeled off, and the adhesive tape is pressure-bonded 3 times with a 2 kg rubber roller to a stainless steel plate and heat-treated at 70 ° C. for 2 hours. Next, the adhesive force F is measured according to the method of JIS-C-2107 (adhesive strength to stainless steel plate, 180 ° peeling method). The percentage of F (F / F ₀ × 100) relative to the adhesive force F ₀ when the adhesive tape “No. 31B” was directly adhered to and peeled from the stainless steel plate was determined as the residual adhesion rate.

(4) Surface roughness (central surface average roughness SRa)
The surface roughness of the coated film of the film is a stylus type using a three-dimensional surface roughness measuring instrument SE-30K manufactured by Kosaka Laboratory, detector: PU-DJ2S, radius of stylus tip: R2 μm, measuring force : 0.7 mN, measurement length: 1 mm, Y feed pitch: 2 μm, number of measurement: 201, low cut-off value: 0.25, wide cut-off value: R + W

Examples 1 to 4 and Comparative Example Using the above samples 1 to 3, the above (2) to (5) were measured.
Further, in the case of the sample 1 described above, the measurement was similarly performed when the cured resin layer (B) was omitted (comparative example). The results are shown in Table 1.

Table 1 Example 1 Example 2 Example 3 Comparative Example Sample Name Sample 1 Sample 2 Sample 3 −
Surface roughness SRa [μm] 0.008 0.009 0.009 0.027
Peeling force [N / 50mm] 0.08 0.08 0.08 0.09
Residual adhesive strength [%] 94 93 93 94

Since the multilayer film of the present invention has improved surface smoothness, it is used in various applications such as capacitors, especially laminated ceramic capacitors and release films.

Claims (4)

On at least one side of the polyester film (A), a cured resin layer (B) made of a cationic photopolymerizable substance, an organopolysiloxane having at least two alkenyl groups directly bonded to silicon atoms in one molecule, and in one molecule multilayer film is that the silicone resin layer obtained by addition reaction of organohydrogenpolysiloxane having at least two hydrogen atoms directly bonded to silicon atom (C) are laminated in this order. 2. The multilayer film according to claim 1, wherein a cured resin layer (B) obtained by irradiating and curing an active energy ray on a curable composition comprising a photocationically polymerizable substance is used. The multilayer film according to claim 1 or 2, wherein the cationic photopolymerizable substance is at least one kind of cationic photopolymerizable substance selected from epoxy group-containing compounds. A polyester film (A) having a thickness of 1 to 300 μm, a cured resin layer (B) having a thickness of 0.1 to 5 μm, and a silicone resin layer (C) having a thickness of 0.01 to 5 μm. The multilayer film according to any one of 1 to 3.