JP7173045B2 - Laminate films, release films and laminates - Google Patents

Description

TECHNICAL FIELD The present invention relates to a laminated film, and more particularly to a laminated film having releasability.

In recent years, the number of automobiles equipped with liquid crystal panels has increased. Such automotive applications are often exposed to high and low temperatures for long periods of time, and adhesives that bond panel constituent members together are required to have a high degree of weather resistance and heat resistance. As a pressure sensitive adhesive suitable for this purpose, a silicone pressure sensitive adhesive with strong adhesiveness is attracting attention.
Silicone adhesives are used in the form of a tape (film) as an adhesive layer, but are usually stored with one or both sides covered with a release film before use. Used by peeling off the mold film. However, the strong adhesive silicone adhesive (adhesive layer) strongly adheres to the widely used organosilicone-coated release film, making it difficult to separate the release film during use.

A fluorinated silicone material having fluorine substituents has been proposed as a method for exhibiting releasability from a molded article formed by molding a mold resin such as a silicone resin composition. (Patent document 1)

Japanese Unexamined Patent Application Publication No. 2011-201035

However, when a fluorinated silicone material is used as the release layer, the adhesion between the polymer film and the release layer is insufficient, causing delamination, or the release layer is not formed uniformly. In some cases, problems such as deterioration of releasability from adherents occurred.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a release film having excellent releasability from an adhesive layer having strong adhesiveness such as a silicone adhesive. .

In order to solve the above-mentioned problems, the present inventors have made intensive studies and found that each layer of a laminated film in which a layer A and a layer B are laminated in this order on at least one side of a polymer film contains fluorine atoms. The inventors have found that the above problems can be solved by controlling the content of fluorine atoms in both layers, and have completed the present invention.
That is, the gist of the present invention is a laminated film in which a layer A and a layer B are laminated in this order on at least one side of a polymer film, wherein both the layers A and B contain fluorine atoms, In addition, the laminated film is characterized in that the content of fluorine atoms in the B layer is higher than the content of fluorine atoms in the A layer.

Further, the gist of the present invention is a laminated film in which a layer A and a layer B are laminated in this order on at least one side of a polymer film, wherein the layer B contains fluorine atoms, and is measured by the following method. The laminated film is characterized by having a normal peel strength of 100 mN/cm or less.
<Measurement of normal peel strength>
A tape with a silicone adhesive (No5413 tape, 50 mm width, manufactured by 3M Japan Co., Ltd.) is attached to the B layer surface of the laminated film, and a 180° peel test is performed at a peel speed of 0.3 m / min.

ADVANTAGE OF THE INVENTION According to this invention, the laminated|multilayer film which has the outstanding peelability with respect to the adhesive layer which has strong adhesiveness, such as a silicone adhesive, can be obtained.

1 is a schematic diagram of a laminated film of the present invention; FIG. It is a schematic diagram which shows the peeling state with the silicone adhesive layer in the laminated|multilayer film of prior art (a) and this invention (b).

Hereinafter, embodiments of the laminated film of the present invention will be described more specifically.
The laminated film of the present invention is a laminated film in which a layer A (undercoat layer) and a layer B (release layer) are laminated in this order on at least one side of a polymer film, as illustrated in FIG.
The laminated film of the present invention will be described below in the order of the polymer film, layer A (undercoat layer) and layer B (release layer).

1. Polymer Film Examples of the polymer film that serves as the base material for the laminated film of the present invention include films in which polymers such as polyethylene, polypropylene, polyester, polystyrene, polycarbonate, polyethersulfone, polyamide, and polyimide are formed into a film. . A mixture of these materials (polymer blend) or a composite of structural units (copolymer) may be used as long as they can be formed into a film.
The polymer film is not particularly limited as long as it is made into a film, and may be a non-stretched film or a stretched film, but a stretched film that is uniaxially or biaxially stretched is preferable. Among them, a biaxially stretched film is more preferable from the viewpoint of balance of mechanical properties and flatness.

The thickness of the polymer film constituting the laminated film in the present invention is not particularly limited as long as it is within a range that can be formed as a film, but is preferably 5 μm or more and 1000 μm or less, more preferably 10 μm or more or 500 μm or less. 15 μm or more or 200 μm or less is more preferable.

Among the films exemplified above, polyester films are preferable because of their excellent physical properties such as heat resistance, flatness, optical properties, and strength. Among them, biaxially stretched polyester films are particularly preferable.
The polyester film may be a single layer or a multilayer film (laminated film) having two or more layers having different properties.
In the present invention, the polyester used for the polyester film may be homopolyester or copolymer polyester. Preferred homopolyesters are those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. Examples of aromatic dicarboxylic acids include terephthalic acid and 2,6-naphthalene dicarboxylic acid, and examples of aliphatic glycols include ethylene glycol, diethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, and the like. be done.

Representative homopolyesters include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and the like. On the other hand, the dicarboxylic acid component of the copolymer polyester includes one or more of isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalene dicarboxylic acid, adipic acid, sebacic acid, and the like. One or more of glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol and the like can be used.

Among them, polyethylene terephthalate in which ethylene terephthalate units account for 60 mol % or more, preferably 80 mol % or more, is preferred in the present invention.
In the present invention, the surface of the polymer film is provided with antistatic properties, sealing properties against exudation (bleeding, plate-out) of compounds and oligomers on the film surface, and light transmittance of the film. An undercoat layer (base coat layer) may be provided in order to improve the adhesion with the layer A (undercoat layer).

The undercoat layer may be formed by either an in-line coating method in which the undercoat layer is formed simultaneously with the formation of the polymer film, or an off-line coating method in which the undercoat layer is separately formed on the already formed film.
When the undercoat layer is provided, it may be formed on at least one surface of the polymer film. When forming on both sides, the same undercoat layer may be formed on both sides, or different undercoat layers may be formed on each side. The undercoat layer may be any of a layer made of an organic substance, a layer made of an inorganic film, and a layer made of a mixture of an organic substance and an inorganic substance.

2. A layer (undercoat layer)
In the present invention, a layer A (undercoat layer) is provided on at least one side of the polymer film.
<Structure of layer A>
The A layer usually contains fluorine atoms. As a result, not only does it have adhesion between the A layer and the later-described B layer, but when it is used as a release film, the B layer and the adhesive layer that is the adherend can be easily peeled off, and the adhesion The body can be easily peeled off.
The method for incorporating fluorine atoms into the A layer is not limited, and at least a compound containing a fluorine atom may be incorporated into the A layer. Specific examples include low-molecular-weight compounds containing fluorine atoms, resins containing fluorine atoms, and the like. Among them, it is preferable to use a resin containing a fluorine atom, and it is particularly preferable that the resin is curable.
Furthermore, when used as a release film, by laminating the B layer on the A layer, the peeling force to the adherend is reduced, and the release film can be easily peeled. According to the present inventor, when the A layer is not laminated on the laminated film, the adherend (adhesive) is also followed in the peeling direction when the laminated film is peeled off, so it is more difficult to peel off the adherend. It was presumed that a large force was required and that peeling was difficult (heavy peeling) (Fig. 2(a)). On the other hand, as in the present invention, when the A layer containing fluorine atoms is laminated on the laminated film, the A layer has relative flexibility, so the A layer acts like a cushion during peeling, and the adherend Since the deformation of is suppressed, it is possible to peel off from the adherend with a smaller force, and it is presumed that peeling became easier (light peeling) (Fig. 2(b)).

<Proportion of fluorine atom content in layer A>
The A layer contains a fluorine atom-containing material, and the fluorine atom content ratio (atom number fraction) of the entire A layer is preferably 50 ppm or more, more preferably 500 ppm or more, from the viewpoint of adhesion and easy peelability. , more preferably 1,000 ppm or more, and particularly preferably 50,000 ppm or more. On the other hand, the upper limit is not particularly limited, but is preferably less than 900,000 ppm, more preferably 800,000 ppm or less, and even more preferably 700,000 ppm or less.
The content of fluorine atoms in the layer A can be confirmed, for example, by analyzing the depth direction by sputter etching in the vicinity of the polymer film in the undercoat layer that constitutes the laminated film by X-ray photoelectron spectroscopy (XPS method). can be done. The fluorine atom content of the A layer can also be quantified by using a material (such as fluorinated silicone) whose fluorine atom content is known in advance as a reference. In addition, when confirming by the XPS method, the fluorine atom content ratio was defined as the ratio of fluorine to all the elements except hydrogen and helium.

By setting the fluorine atom content ratio of the A layer to the above range, the B layer (release layer) similarly containing fluorine atoms can be uniformly applied when provided on the A layer by a coating method, and after coating or lamination The adhesion between the A layer and the B layer can also be enhanced.
If the above fluorine atom content ratio is achieved for the entire A layer, the resin used for the A layer may be a resin containing a fluorine atom alone or mixed with a resin not containing a fluorine atom (non-fluorinated resin). good too.

Note that the A layer may have a composition in which the fluorine atom content ratio is graded in the thickness direction. The same applies to the B layer, which will be described later.

<Resin Containing Fluorine Atoms>
Resins containing fluorine atoms used in the present invention include resins containing fluorine atoms in the side chain portion of the resin skeleton. Specific examples of resins containing fluorine atoms include fluorinated silicone resins, fluorine-containing hydrocarbon resins such as polytetrafluoroethylene, and various other fluorinated resins. A fluorinated silicone resin is preferred from the viewpoint of releasability.

Both curable and non-curable fluorinated silicone resins can be used without particular limitation. Among them, a curable fluorinated silicone resin is preferable in terms of forming a stronger layer. Moreover, the fluorinated silicone resin may be solvent-type, non-solvent-type, or a mixture thereof. A curable fluorinated silicone resin usually has a functional group, such as an alkenyl group or a hydrosilyl group, that can form a crosslinked structure by reaction (curing).

Examples of curable fluorinated silicone resins include KP-911 and X-70-201S manufactured by Shin-Etsu Chemical Co., Ltd.; , BY24-903, Syl-off 3062, Q2-7785 and the like.
The fluorine atom content (atomic fraction) of the fluorinated silicone resin is generally several thousand ppm to several tens of percent.

<Resin containing no fluorine atom>
Examples of resins containing no fluorine atoms (non-fluorinated resins) used in the present invention include silicone resins, polyolefin resins, and acrylic resins. Silicone resins are preferred from the viewpoint of compatibility (in the present invention, silicone resins containing no fluorine atoms are sometimes referred to as "non-fluorinated silicone resins"). As the non-fluorinated resin, either a curable resin or a non-curable resin may be used, or a mixture of the two may be used. Like the curable fluorinated silicone resin, the non-curable fluorinated silicone resin usually has a functional group such as an alkenyl group or a hydrosilyl group that can form a crosslinked structure by reaction (curing).

Curable non-fluorinated silicone resin The curable non-fluorinated silicone resin may be solvent type or non-solvent type.
Specific examples of curable non-fluorinated silicone resins include KNS-3051, KNS-320A, KNS-316, KNS-3002, KNS-3300, X-62-1387 and KS-3656 manufactured by Shin-Etsu Chemical Co., Ltd. , KS-837, X-62-2829, KS-3650, KS-847, KS-847T, KS-847H, KS-776L, KS-776A, KS-774, KS-3703T, KS-3601, KS-830E , X-62-2825, X-62-9201-A, X-62-9201B, KM3951, KM-768, X-52-6015, KF-2005, X-62-7205, X-62-7028-A , X-62-7028-B, X-62-7052, X-62-7622, X-62-7660, X-62-7655; Dow Corning Toray Co., Ltd. SP7017, SP7015, SP7025, SP7031, LTC1006L, LTC1063L, LTC1036M, LTC1056L, SRX357, SRX211, SRX345, SRX370, LTC300B, LTC310, LTC355A, LTC759, LTC755, LTC750A, LTC752, LTC765, LTC861, LTC and the like.
Further, a heavy release additive may be added to the curable non-fluorinated silicone resin, examples of which include KS-3800 manufactured by Shin-Etsu Chemical Co., Ltd.; SD7292 and BY24 manufactured by Dow Corning Toray Co., Ltd. -4980 and the like.

The above curable non-fluorinated silicone may be used alone, or two or more different types may be mixed and used. By mixing two or more types of curable non-fluorinated silicones, it is possible to adjust the curing reaction, adjust the coating liquid viscosity of the A layer, and further improve the wettability and reactivity of the B layer. can be done. At that time, solvent-free silicones may be mixed together, solvent-type silicones may be mixed together, or solvent-free silicones and solvent-type silicones may be mixed. In particular, when the film thickness of the A layer is increased in order to obtain a release film that is easier to release, the solid content concentration of the coating solution forming the A layer tends to increase. As a result, the viscosity of the coating liquid increases, which may cause problems such as deterioration of coating appearance and increased unevenness in thickness. Therefore, by mixing a solvent-free silicone and a solvent-type silicone, the viscosity of the coating liquid can be lowered, and the A layer having a good coating appearance and a small variation in thickness can be formed.

Here, "solvent-free silicone" is a silicone with a viscosity that allows coating without being diluted with a solvent, and is composed of short polysiloxane chains and has a relatively low molecular weight.
The viscosity of the solvent-free silicone is preferably less than 1000 mPa s when the viscosity is 100% concentration, especially 50 mPa s or more or 900 mPa s or less, especially 80 mPa s or more or 800 mPa s. More preferably:

On the other hand, "solvent-type silicone" is a silicone having a viscosity so high that it cannot be coated without being diluted with a solvent, and has a relatively high molecular weight.
The viscosity of the solvent-type silicone is preferably 1000 mPa s or more when a 30% toluene solution is used, especially 2000 mPa s or more or 20000 mPa s or less, especially 3000 mPa s or more or 18000 mPa s or less. It is more preferable to have

By including a non-curable non-fluorinated silicone resin in the non-curable non-fluorinated silicone resin A layer, the controllability of the curing reaction can be improved, and sufficient flexibility is imparted to the A layer. The storage stability of the laminate laminated with the pressure-sensitive adhesive layer is also improved. As the non-curable non-fluorinated silicone resin, any of the above-listed non-fluorinated silicone resins having no reactive functional group can be used without particular limitation. Specifically, an organopolysiloxane represented by the following general formula (I) is preferred.
R ₃ SiO(R ₂ SiO) _m SiR ₃ (I)
(In the formula, R is the same or different monovalent hydrocarbon group having no aliphatic unsaturated bond, and m represents a positive integer.)

The mass mixing ratio of the curable silicone resin (total of fluorinated and non-fluorinated) and the non-curable non-fluorinated silicone resin is preferably in the range of 1:1000 to 1000:1, preferably 1:100 to It is more preferably in the range of 100:1, even more preferably in the range of 1:50 to 50:1. Particularly preferred is in the range from 1:20 to 20:1, with 1:1 to 20:1 being especially preferred.

The thickness of the layer A is preferably 10 nm or more and 100 μm or less, more preferably 20 nm or more and 10 μm or less, and even more preferably 50 nm or more and 1 μm or less. A particularly preferable range is 80 nm or more and 800 nm or less.
When this film thickness is too thin, such as less than 10 nm, not only the adhesion between the A layer and the B layer is deteriorated, but also the releasability between the silicone pressure-sensitive adhesive layer and the B layer of the laminated film tends to be deteriorated. . On the other hand, if the film thickness of the A layer is too thick, the amount of material used increases, and it is difficult to obtain an increase in the effect commensurate with the increase in the amount used.

3. B layer (release layer)
<Structure of Layer B>
As a material for forming the layer B (releasing layer), the same fluorine-containing resin as described for the layer A (undercoat layer) can be used. Among these, fluorinated silicone resins are preferable, and curable fluorinated silicone resins are particularly preferable, from the viewpoint of releasability from the adherend. By using a curable fluorinated silicone resin for the layer B (release layer), it is possible to obtain a release film having stable releasability from the silicone pressure-sensitive adhesive layer.

Layer B may be formed of a curable fluorinated silicone resin alone, or may be a mixture of multiple materials such as a mixture with a curable non-fluorinated silicone resin.
It is particularly preferable that the coating liquid for forming the B layer contains a fluorine-based solvent containing a fluorine atom for the purpose of enhancing the wettability with respect to the A layer.

If the thickness of the layer B is too thin, it may be difficult to obtain the effects of the present invention. .
The lower limit of the thickness of the layer B is preferably 5 nm or more, more preferably 10 nm or more, and particularly preferably 20 nm or more. Moreover, the upper limit thereof is preferably 50 μm or less, more preferably 1 μm or less, and particularly preferably 500 nm or less.

<Proportion of Fluorine Atoms in Layer B>
In the laminated film of the present invention, a layer B (release layer) is formed on a layer A (undercoat layer). Suitable materials for the B layer are the same as those described in the description of the A layer, but from the viewpoint of adhesion and easy peelability, the content of fluorine atoms per unit volume contained in the B layer is It must be contained more than the A layer.

In the present invention, the lower limit of the fluorine atom content ratio (atom number fraction) contained in the B layer measured by the SIMS method or the like is preferably 3,000 ppm or more, more preferably 5,000 ppm or more, 10,000 ppm or more is more preferable, and 20,000 ppm or more is particularly preferable. On the other hand, the upper limit is not particularly limited, but is preferably 900,000 ppm or less, more preferably 800,000 ppm or less, and particularly preferably 700,000 ppm or less.
The fluorine atom content of layer B can be confirmed, for example, by secondary ion mass spectroscopy (SIMS method) or X-ray photoelectron spectroscopy (XPS method) on the release layer surface of the laminated film. The fluorine atom content of layer B can also be quantified by using a material (such as fluorinated silicone) whose fluorine atom content is known in advance as a reference. In addition, when confirming by the XPS method, the fluorine atom content ratio was defined as the ratio of fluorine to all the elements except hydrogen and helium.

As described above, the case where the A layer and the B layer having different fluorine atom content ratios are sequentially laminated has been described. ), it may be possible to obtain a structure substantially equivalent to the lamination structure of the A layer and the B layer. For example, a resin containing a fluorine atom and a resin not containing a fluorine atom are diluted with a solvent to form a coating solution, and the coating solution is applied to at least one surface of a polymer film and dried to obtain a resin containing a fluorine atom. A method of forming a layer having a gradient structure in the thickness direction by concentrating it on the surface of the layer is exemplified. In the case where such a lamination process can be employed, it is not necessarily limited to the stepwise sequential lamination of the A layer and the B layer. Among the layers, the B layer is on the surface side and the A layer is on the polymer film side.
By forming the A layer and the B layer to have a gradient structure in this way, it is expected that the adhesion of the interface between the A layer and the polymer film and the interface between the A layer and the B layer will be substantially improved. Furthermore, since the content of fluorine atoms on the surface of the B layer can be increased, it may be possible to further improve the easy peelability while keeping the content of the resin containing fluorine atoms in the entire laminated film low.

4. Fluorine atom content ratio In the present invention, from the viewpoint of adhesion and easy peelability, in addition to the fact that both layers A and B contain fluorine atoms, the content ratio is the silicone that serves as the base material for each layer. It preferably has a specific relationship with the content of methylsiloxane ions (CH ₃ SiO ₂ ⁻ ) in the resin.
That is, the ratio of the fluorine ion content to the methylsiloxane ion content in the layer B calculated by the SIMS method or the like ([F ⁻ ]/[CH ₃ SiO ₂ ⁻ ]) (hereinafter referred to as “fluorine atom content ratio”) ) is preferably larger than the fluorine atom content ratio of the A layer.

Further, the fluorine atom content ratio of each of the A layer and the B layer is preferably 1 or more and 1,000 or less for the A layer, and 3 or more and 5,000 or less for the B layer.
The lower limit of the fluorine atom content ratio of the layer B is preferably 5 or more, more preferably 10 or more, and even more preferably 20 or more. Moreover, the upper limit is preferably 3,000 or less, and a more preferable upper limit is 1,000 or less.

The fluorine atom content ratio of layer B is preferably 1.1 times or more, more preferably 1.5 times or more, that of layer A from the viewpoint of easy release from the silicone pressure-sensitive adhesive layer. 2 times or more is more preferable, 3 times or more is particularly preferable, and 5 times or more is most preferable. On the other hand, the upper limit is not particularly limited, but from the viewpoint of adhesion between the A layer and the B layer, it is preferably 1000 times or less, more preferably 100 times or less.
In the present invention, the fluorine atom content ratio (atomic number fraction) in the B layer is 1 of the fluorine atom content ratio (atomic number fraction) in the A layer from the viewpoint of easy release from the silicone pressure-sensitive adhesive layer. 0.1 times or more is preferable, 1.5 times or more is more preferable, 2 times or more is more preferable, 3 times or more is particularly preferable, and 5 times or more is most preferable. On the other hand, the upper limit is not particularly limited, but from the viewpoint of adhesion between the A layer and the B layer, it is preferably 1000 times or less, more preferably 100 times or less.
Here, the "fluorine atom content ratio (atomic number fraction)" means the ratio of fluorine atoms to the layer. When both the A layer and the B layer are substantially composed of a silicone resin (including fluorinated, non-fluorinated, curable and non-curable), the above "fluorine atom content ratio" Regarding the "fluorine atom content ratio (atomic number fraction)", the ratios of the A layer and the B layer have the same value.

By setting the fluorine atom content ratio of the B layer within the above range, sufficient adhesion can be obtained between the A layer and the B layer, and good releasability between the B layer and the silicone pressure-sensitive adhesive layer can be exhibited. can be done.
Further, since the fluorine atom content and/or the fluorine atom content ratio of the B layer is higher than that of the A layer, sufficient adhesion between the A layer and the B layer can be obtained, and good adhesion between the B layer and the silicone pressure-sensitive adhesive layer can be achieved. Peelability can be stably exhibited.

The fluorine atom content ratio or the fluorine atom content ratio of the layers A and B can be calculated by structural analysis of the coating agent by a nuclear magnetic resonance spectroscopy (NMR) method. It can be quantified by mass spectrometry (SIMS method), X-ray electron spectroscopy (XPS method), or the like.
In the measurement by the SIMS method or the XPS method, the fluorine atom content rate of each layer can also be quantified based on a material (fluorinated silicone, etc.) whose fluorine atom content rate is known in advance.
When fluorine atoms are not uniformly present in each of the A layer and the B layer (for example, when the above-described tilted structure is used), the total amount of fluorine atoms contained in each layer measured by SIMS method etc. The fluorine atom content ratio per unit volume obtained by dividing by the volume of is used as the fluorine atom content ratio of each of the A layer and the B layer.

<Other compounding agents>
Regarding the A layer and the B layer, the coating liquid containing the curable non-fluorinated silicone resin and the curable fluorinated silicone resin preferably contains a cross-linking agent, a catalyst, and a reaction initiator (reaction accelerator). . Commercially available paints containing curable silicone resins sometimes contain cross-linking agents and catalysts from the beginning.

In forming the A layer and the B layer, it is preferable that a cross-linking agent is contained in order to form a cross-linked structure by reacting with the reactive functional groups contained in the resin. Examples of cross-linking agents include vinylsiloxanes and organosiloxanes having hydrosiloxane moieties. Specific examples of the cross-linking agent include SP7297, 7560, 3062A, 3062B, 3062C, and 3062D manufactured by Dow Corning Toray Co., Ltd.
Moreover, the cross-linking agent may contain a site having a fluorine substituent, and a silane coupling agent having a fluorinated substituent may be used.

Moreover, in forming the A layer and the B layer, it is preferable to contain a catalyst that promotes an addition-type reaction, and it is particularly preferable to contain a platinum catalyst. Examples of platinum catalysts include platinum-based compounds such as chloroplatinic acid, alcohol solutions of chloroplatinic acid, complexes of chloroplatinic acid and olefins, complexes of chloroplatinic acid and alkenylsiloxane, platinum black, platinum-supported silica, and platinum-supported activated carbon. are exemplified. The platinum catalyst may be used singly or in combination of two or more.
Specific examples of the catalyst include CAT PL-50T manufactured by Shin-Etsu Chemical Co., Ltd., and SRX212, SRX212P, NC-25 and FS XK-3077 manufactured by Dow Corning Toray Co., Ltd.

Examples of other additives that can be added to the layers A and B include (meth)acrylic acid alkyl esters having an ester group having 1 to 20 carbon atoms, acrylic resins, and olefin resins. Among them, a silane coupling agent having a fluorinated substituent is preferred.

5. Physical properties of the laminated film of the present invention <Normal peel strength>
The laminate film of the present invention preferably has a normal peel strength of 100 mN/cm or less.
When the laminated film is used as a release film, the lower the normal peel strength, the less force required for peeling from the pressure-sensitive adhesive layer. Therefore, it is possible to suppress defects such as failure of peeling and deformation of the adhesive layer in the production process such as peeling the release film from the laminate in which the adhesive layer is laminated and sticking the adhesive layer to various members. can be done. Above all, the laminated film of the present invention can suppress the above problems and have low releasability even with a highly adhesive layer such as a silicone adhesive. In addition, in a laminate having release films on both sides of an adhesive layer as release films, it is possible to prevent a phenomenon in which the release films on the unintended side are peeled off.
From this point of view, the normal peel force is preferably 70 mN/cm or less, more preferably 40 mN/cm or less, particularly preferably 35 mN/cm or less, and most preferably 30 mN/cm or less. preferable. On the other hand, the lower limit is not particularly limited, but is preferably 1 mN/cm or more, more preferably 3 mN/cm or more, from the viewpoint of storage stability of a laminate obtained by laminating a laminated film and an adhesive layer.

As a method for lowering the normal peeling force, a method such as adjusting the fluorine atom content ratio of the A layer or the B layer can be mentioned. In addition, the normal peel strength shall be measured by the method described in Examples described later.

6. Laminated Structure The laminated film of the present invention may have a structure in which a layer A is provided on one side or both sides of a polymer film, and a layer B is provided on the A layer. If necessary, other layers may be interposed between the polymer film and the A layer and between the A layer and the B layer.
Examples of other layers include an antistatic layer having antistatic properties, and an oligomer sealing layer for sealing blending and oligomer bleeding (bleeding, plate-out) on the film surface.

The layers such as the antistatic layer and the oligomer sealing layer can be formed by either an in-line coating method, which is formed at the same time as the polymer film is formed, or an offline coating method, which is formed in a separate process on the already formed polymer film. can also be formed using

The thickness of the entire laminate film in the invention is preferably 5 μm or more and 1250 μm or less, more preferably 10 μm or more and 500 μm or less, and even more preferably 10 to 200 μm or less.

7. Method for producing the laminated film of the present invention <Production method>
(1) Polymer film As the polymer film that serves as the base material of the laminated film of the present invention, films formed into films of polyethylene, polypropylene, polyester, polystyrene, polycarbonate, and other polymer materials are used as described above. .

Hereinafter, a method for producing a polyester film will be described as an example.
As a method for producing the polyester film used in the present invention, a method of obtaining an unstretched sheet by cooling and solidifying a molten sheet extruded from a die using a polyester raw material such as the polyethylene terephthalate described above with a cooling roll is preferable. . At this time, it is preferable to increase the adhesion between the sheet and the rotary cooling drum by an electrostatic application adhesion method and/or a liquid coating adhesion method in order to improve the flatness of the sheet.

The obtained unstretched sheet can be used as it is, but it is preferably at least uniaxially stretched, more preferably biaxially stretched. Good mechanical strength and dimensional stability can be obtained by stretching the polyester film uniaxially or more. Moreover, when it is used as a release film, when an adherend (adhesive layer) is laminated to produce a pressure-sensitive adhesive sheet with a laminated film, it is possible to suppress the occurrence of problems during lamination.
The stretching conditions are not particularly limited either. For example, an unstretched sheet is stretched 2 to 6 times in the longitudinal direction (longitudinal direction) at 70 to 145°C by a roll stretching method to obtain a uniaxially stretched polyester film, followed by a tenter. A biaxially stretched film is obtained by stretching 2 to 6 times at 80 to 160.degree.
In this case, a method of relaxing 0.1 to 20% in the longitudinal direction and/or the width direction in the heat treatment zone and/or the cooling zone at the exit of the heat treatment is more preferable.

(2) Formation of A layer (undercoat layer) and B layer (release layer) The method for forming the A layer and B layer is not limited, and may be formed by a coextrusion method or the like. is preferred.
The A layer and the B layer may be applied once, or two or more times. When the A layer and the B layer are formed by applying two or more coatings, different coating liquids may be applied. However, at least one of the coating liquids must contain fluorine atoms.

The coating method may be either in-line coating or off-line coating. For example, a coating technique such as that described in "Coating Method" (written by Yuji Harasaki, published by Maki Shoten, 1979) can be used.
Examples of coating heads include air doctor coaters, blade coaters, rod coaters, knife coaters, squeeze coaters, impregnation coaters, reverse roll coaters, transfer roll coaters, gravure coaters, kiss roll coaters, cast coaters, spray coaters, curtain coaters, calendar coaters. , an extrusion coater, and the like.

The solid content mass concentration of the coating solution forming the A layer and the B layer is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.1% by mass or more. On the other hand, the upper limit is preferably 90% by mass or less, more preferably 50% by mass or less, and particularly preferably 20% by mass or less.
A solvent for dilution may be a polar solvent or a non-polar solvent. A fluorine solvent containing fluorine atoms may also be used. Furthermore, two or more of the above solvents may be mixed and used. In particular, the coating liquid for forming the B layer preferably contains a fluorine solvent having a fluorine atom for the purpose of enhancing the wettability with respect to the A layer.
Polar solvents include alcohols such as ethanol and (isopropyl alcohol), esters such as methyl acetate, ethyl acetate, (iso)propyl acetate, (iso)butyl acetate, (iso)pentyl acetate, ethyl lactate, and ethyl benzoate. , ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, diacetone alcohol, diisobutyl ketone, ethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, etc. glycols, N-methyl-2-pyrrolidone, N,N-dimethylformamide, tetrahydrofuran, acetonitrile and the like.
Non-polar solvents include aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as hexane, heptane and octane; hydrocarbons having branched structures such as isohexane, isooctane and isononane; alicyclic hydrocarbons such as heptane and cyclooctane; dioxane; Examples of fluorine solvents include hydrofluoroethers, m-xylene hexafluoride, tridecafluorooctane, and the like.

As a method for forming these layers, as a coating liquid, a coating liquid having a fluorine atom content ratio corresponding to each layer after coating and drying is prepared in advance, and a method using this is exemplified. can.
Further, by using a curable non-fluorinated silicone resin and mixing a predetermined amount of this with a fluorinated material to prepare a coating liquid having a composition corresponding to the layer A/layer B, and then coating and drying, A layer and/or B layer containing desired fluorine atoms can be formed. This method is preferable because a release film having A layer/B layer with a predetermined fluorine atom content can be produced more easily.
Further, these A and B layers can be formed by coating and drying the A layer and then coating and drying the B layer. In the present invention, the B layer is coated after the A layer is coated. It can be formed by a wet coating method that is followed by drying, which is expected to shorten the production process and improve energy efficiency.

Alternatively, the A layer is formed by coating a mixture of a curable fluorinated silicone resin and a curable non-fluorinated silicone resin, and then the B layer is a solution based on the curable fluorinated silicone resin. There is a method of forming by coating, and this method is more preferable because the release film can be stably produced.
Alternatively, a non-fluorinated resin can be pre-coated and then a dry process such as carbon tetrafluoride (CF ₄ ) plasma treatment can be used to create the fluorinated layer. However, since this method requires a chamber for plasma processing, it can be said to be suitable for large-scale production.

In the case of using so-called in-line coating, which is coating in the process of producing a polymer film, as the method for producing the laminated film of the present invention, both the A layer and the B layer may be in-line coated, or only the A layer may be in-line coated. , and the B layer may be an offline coating.
When both the A layer and the B layer are provided by offline coating, even if they are continuously formed in one "base film unwinding-winding step", or multiple times "base film unwinding- The former may be formed sequentially through the winding process, but the former is a particularly preferable method because the manufacturing process is simple and the manufacturing can be performed at a lower cost.
Furthermore, by making the amount of heat applied to the film during the formation of the A layer lower than the amount of heat applied during the formation of the B layer, it is possible to suppress the deterioration of the film flatness during the formation of the B layer, and the occurrence of uneven coating of the B layer. It is preferable because it can be effectively prevented.

8. Method of Using Laminated Film Since the laminated film of the present invention has excellent releasability, it can be provided, for example, as a pressure-sensitive adhesive sheet with a laminated film having a structure in which the laminated film and the pressure-sensitive adhesive layer are laminated. In particular, since the laminated film of the present invention has excellent releasability even with respect to a silicone pressure-sensitive adhesive having strong adhesiveness, for example, the laminated film and a pressure-sensitive adhesive layer made of a silicone pressure-sensitive adhesive are laminated. It can be provided as a pressure-sensitive adhesive sheet with a laminated film.
However, the usage method of the laminated film is not limited to such usage method. For example, since the laminated film contains fluorine atoms, it is excellent in water resistance, water repellency, oil resistance, oil repellency, anti-fogging, stain resistance, chemical resistance, corrosion resistance, etc. Examples include substrates, optical member protective films, films for building materials, films for agriculture, highly water-repellent films, films for packaging, decorative films, and surface protective films. In the case of applications where the B layer surface is used as the outermost surface, an adhesive layer, an adhesive layer, a heat seal layer, etc. may be provided on the surface of the polymer film opposite to the surface having the A layer and the B layer. .

<Silicone adhesive>
Examples of silicone pressure-sensitive adhesives include addition reaction type, peroxide curing type and condensation reaction type silicone pressure-sensitive adhesives. Among them, the addition reaction type silicone pressure-sensitive adhesive is preferably used from the viewpoint that it can be cured at a low temperature in a short time. These addition-reactive silicone pressure-sensitive adhesives cure when the pressure-sensitive adhesive layer is formed on the support.
When an addition-reactive silicone pressure-sensitive adhesive is used as the silicone pressure-sensitive adhesive, the silicone pressure-sensitive adhesive may contain a catalyst such as a platinum catalyst.
For example, the addition reaction type silicone pressure-sensitive adhesive can be applied to a support after a silicone resin solution diluted with a solvent such as toluene is added with a catalyst such as a platinum catalyst and stirred to be uniform, if necessary. and can be cured at 100-130° C./1-5 minutes.
In addition, if necessary, a cross-linking agent or an additive for controlling adhesive force may be added to the addition reaction type silicone pressure-sensitive adhesive, or the support may be subjected to a primer treatment before forming the pressure-sensitive adhesive layer. good too.

Commercially available silicone resins used for the addition reaction type silicone adhesive include SD4580PSA, SD4584PSA, SD4585PSA, SD4587LPSA, SD4560PSA, SD4570PSA, SD4600FCPSA, SD4593PSA, DC7651ADHESIVE, DC7652ADHESIVE, LTC-755, and LTC-310 (all of which are manufactured by Dow Toray Co., Ltd.). Corning), KR-3700, KR-3701, X-40-3237-1, X-40-3240, X-40-3291-1, X-40-3229, X-40-3323, X-40 -3306, X-40-3270-1 (both manufactured by Shin-Etsu Chemical Co., Ltd.), AS-PSA001, AS-PSA002, AS-PSA003, AS-PSA004, AS-PSA005, AS-PSA012, AS-PSA014, PSA-7465 (all manufactured by Arakawa Chemical Industries, Ltd.), TSR1512, TSR1516, and TSR1521 (all manufactured by Momentive Performance Materials).

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. In the following examples, the raw materials described as "addition type" all mean "curability".

(1) Evaluation method (1-1) Normal peel strength
In an environment of 23° C., a tape with a silicone pressure-sensitive adhesive (No.5413 tape, 50 mm width, manufactured by 3M Japan) was attached to the layer B (releasing layer) surface of the laminated film, and set in a peel tester. The normal peel strength was measured under the conditions of a peel speed of 0.3 m/min and a peel angle of 180°.

(1-2) Fluorine Atom Content Ratio, Fluorine Atom Content Ratio The fluorine atom content ratio in the A layer and the B layer was evaluated using TOF-SIMS (TRIF V, manufactured by Ulvac-Phi).
Au ³⁺ was used as primary ions and the accelerating voltage was 30 kV.
In order to evaluate the fluorine atom content ratio per unit volume, etching with Ar gas (voltage: 5 kV, current: 2 nA, etching rate: 20 nm / min (PET film conversion)) was performed for 0 min, 1 min, 2 min, and 3 min. Fluorine atom content ratio per unit _volume ^{(“F − ” /} “ _{CH 3} SiO ₂ ⁻ ”).
Further, the value of [ratio of fluorine atom content in layer B]/[ratio of fluorine atom content in layer A] was taken as the ratio of the fluorine atom content ratio. This value has the same meaning as the result of measuring the fluorine atom content ratio (atomic number fraction) of each layer A and B using XPS and calculating the ratio of the values of each layer.

[Example 1]
(Coating liquid 1)
The following compositions were mixed and diluted with a mixed solvent of isopropyl ether and ethyl acetate (mass ratio = 1:1) so that the solid content concentration was 4% by mass to prepare "Coating liquid 1".

<Coating liquid 1 composition>
Addition-type organosilicone (manufactured by Shin-Etsu Chemical Co., Ltd., KS-847): 67 parts by mass Platinum catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., CAT-PL-50T): 0.7 parts by mass Addition-type fluorinated silicone (manufactured by Dow Corning Toray Co., Ltd. , Syl-off 3062): 100 parts by mass Crosslinking agent (manufactured by Dow Corning Toray Co., Syl-off 3062A): 0.5 parts by mass Platinum catalyst (manufactured by Toray Dow Corning Co., FSXK-3077): 0.5 mass Department

(Coating liquid 2)
The following composition is mixed and diluted with a mixed solvent of FS thinner (manufactured by Shin-Etsu Chemical Co., Ltd.) / ethyl acetate = 1: 1 (mass ratio) so that the solid content concentration is 0.5% by mass. A coating liquid 2” was prepared.

<Coating liquid 2 composition>
Addition type fluorinated silicone (manufactured by Shin-Etsu Chemical Co., Ltd., X-70-201S): 100 parts by mass platinum catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., CAT-PL-50T): 0.5 parts by mass

(Creation of laminated film)
A PET film ("T100-38" manufactured by Mitsubishi Chemical Co., Ltd., thickness 38 μm) was used as the polymer film. was dried for 30 seconds to cure the layer A resin, thereby producing a polymer film having a layer A (undercoat layer).
On the A layer of the polymer film having the A layer (undercoat layer), the above coating liquid 2 is further applied using a bar coater (No. 4 bar) and dried in an oven at 150° C. for 30 seconds to form the resin of the B layer. was cured to prepare a laminated film in which a layer B (release layer) was provided on a layer A (undercoat layer).

[Example 2]
A laminated film was produced in the same manner as in Example 1, except that the coating liquid 2 had a solid content concentration of 4% by mass.
Since the coating liquid 2 is applied using the same bar coater as in Example 1, the thickness of the layer B is increased compared to that in Example 1 by increasing the solid content concentration.

[Comparative Example 1]
A polymer film was substantially formed in the same manner as in Example 1 except that only the coating solution 2 was applied by a bar coater (No. 4 bar) without forming an A layer (undercoat layer) on the polymer film. and a layer B (releasing layer) alone.

[Comparative Example 2]
A laminate film was produced in the same manner as in Comparative Example 1, except that the coating liquid 2 had a solid content concentration of 4% by mass.
Since the same bar coater as in Comparative Example 1 is used to apply the coating liquid 2, the thickness of the B layer is increased compared to Comparative Example 1 by increasing the solid content concentration.

[Comparative Example 3]
Substantially a polymer film was formed in the same manner as in Example 1 except that the B layer (release layer) was not formed on the A layer (undercoat layer) without applying the coating liquid 2. A laminated film consisting of only layer A (undercoat layer) was produced.

[Comparative Example 4]
(Coating liquid 3)
A coating liquid 3 was prepared with the following composition.
<Coating liquid 3 composition>
Addition type organosilicone (manufactured by Shin-Etsu Chemical Co., Ltd., KS-847H): 67 parts by mass Platinum catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., CAT-PL-50T): 0.7 parts by mass Mix the above composition with n-hexane and MEK It was diluted with a solvent (mass ratio=1:1) so that the solid content concentration was 4% by mass.

(Creation of laminated film)
The above coating liquid 3 was applied on the polymer film by a bar coater (No. 4 bar) and dried in an oven at 150° C. for 30 seconds to form a layer A (undercoat layer).
Next, an attempt was made to coat the coating liquid 2 on the layer A (undercoat layer) using a bar coater (No. 4 bar). However, the coating liquid 2 was not uniformly applied on the A layer (undercoat layer), and a phenomenon (repellence) occurred in which it became dotted or linear (mesh). could not be formed.

[Comparative Example 5]
An attempt was made to produce a laminated film in the same manner as in Comparative Example 4, except that the coating liquid 2 had a solid concentration of 4% by mass for the layer B (releasing layer). However, the "coating liquid 2" was not uniformly applied on the A layer (undercoat layer), and a phenomenon (repellence) occurred in which it became dotted or linear (mesh), so the B layer (release layer) ) could not be formed.

[Example 3]
(Coating liquid 4)
The following compositions were mixed and diluted with a mixed solvent of isopropyl ether and ethyl acetate (mass ratio=1:1) so that the solid content concentration was 4% by mass to prepare "Coating Liquid 4".
<Coating liquid 4 composition>
Addition-type organosilicone (manufactured by Shin-Etsu Chemical Co., Ltd., KS-847): 133 parts by mass Platinum catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., CAT-PL-50T): 1.3 parts by mass Addition-type fluorinated silicone (manufactured by Dow Corning Toray Co., Ltd. , Syl-off 3062): 100 parts by mass Crosslinking agent (manufactured by Dow Corning Toray Co., Syl-off 3062A): 0.5 parts by mass Platinum catalyst (manufactured by Toray Dow Corning Co., FSXK-3077): 0.5 mass Department

(Creation of laminated film)
Coating liquid 4 instead of coating liquid 1 was coated on a polymer film and then cured. A laminated film was produced in the same manner as in Example 1, except that the coating liquid 2 was applied.

[Example 4]
(Coating liquid 5)
The following compositions were mixed and diluted with a mixed solvent of isopropyl ether and ethyl acetate (mass ratio=1:1) so that the solid content concentration was 4% by mass to prepare "Coating Liquid 5".
<Coating liquid 5 composition>
Addition-type organosilicone (manufactured by Shin-Etsu Chemical Co., Ltd., KS-847): 200 parts by mass Platinum catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., CAT-PL-50T): 2.0 parts by mass Addition-type fluorinated silicone (manufactured by Dow Corning Toray Co., Ltd. , Syl-off 3062): 100 parts by mass Crosslinking agent (manufactured by Dow Corning Toray Co., Syl-off 3062A): 0.5 parts by mass Platinum catalyst (manufactured by Toray Dow Corning Co., FSXK-3077): 0.5 mass Department

(Creation of laminated film)
A laminated film was produced in the same manner as in Example 3, except that the coating liquid 5 was applied on the polymer film instead of the coating liquid 4 to form a layer A (undercoat layer).

[Example 5]
(Coating liquid 6)
The following compositions were mixed and diluted with a mixed solvent of isopropyl ether and ethyl acetate (mass ratio = 1:1) so that the solid content concentration was 4% by mass to prepare "Coating liquid 6".
<Coating liquid 6 composition>
Addition type organosilicone (manufactured by Shin-Etsu Chemical Co., Ltd., KS-847): 267 parts by mass Platinum catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., CAT-PL-50T): 2.0 parts by mass Addition-type fluorinated silicone (manufactured by Dow Corning Toray Co., Ltd. , Syl-off 3062): 100 parts by mass Crosslinking agent (manufactured by Dow Corning Toray Co., Syl-off 3062A): 0.5 parts by mass Platinum catalyst (manufactured by Toray Dow Corning Co., FSXK-3077): 0.5 mass Department

(Creation of laminated film)
A laminated film was produced in the same manner as in Example 3, except that the coating liquid 6 was applied on the polymer film instead of the coating liquid 4 to form a layer A (undercoat layer).

(3) Evaluation of Results Regarding the obtained laminated film, the content ratio of fluorine atoms in layer A (undercoat layer) and layer B (releasing layer) and normal peel strength using a silicone adhesive tape were measured. The results are shown in Table 1 below.
In Examples 1 and 2, since the A layer (undercoat layer) and the B layer (release layer) defined in the present invention were formed on the PET film, a film of only the B layer (release layer) was used. It was found that better peelability was obtained than in Comparative Examples 1 and 2.

In particular, in the laminated film of Example 1, despite the fact that the thickness of the B layer (release layer) is thin (the concentration of the coating liquid 2 is "0.5% by mass"), The same level of releasability as that of the release film of Example 2 (concentration of coating liquid 2 is "4% by mass") with a thick layer B (release layer) is obtained. From this, it was found that a release film having excellent releasability from a silicone pressure-sensitive adhesive can be produced with a smaller amount of fluorine-based material.
In addition, the release films of Examples 3 to 5, in which the content of fluorine atoms in the layer A (undercoat layer) is smaller than that of Example 1, exhibited the same level of peelability as that of the release film of Example 1. Therefore, it was found that a release film having excellent releasability from a silicone pressure-sensitive adhesive can be produced with a smaller amount of fluorine-based material.

In order to evaluate the fluorine atom content ratio of each layer, the fluorine atom content ratio was measured by TOF-SIMS for the samples of Comparative Example 3 (A layer only) and Comparative Example 2 (B layer only). layer value. As a result, it was confirmed that the B layer contained more fluorine atoms per unit volume than the A layer.
Further, since the composition of the coating liquid was the same, this value was used as the value of the fluorine atom content ratio of each layer in Examples 1 and 2 and Comparative Example 1. Further, the fluorine atom content ratio of the layer A in Examples 3 to 5 was obtained by calculating from the raw material composition ratio based on the value of the fluorine atom content ratio in Example 1.
The fluorine atom content of the A layer is the highest on the surface (etching time 0 minutes in TOF-SIMS), and decreases as the etching time increases (that is, closer to the base PET film side). It is considered that a tilted structure with a high atomic content ratio is formed. The values shown in Table 1 are average values in the thickness direction.

1 polymer film 2 A layer (undercoat layer)
3 B layer (release layer)
4 Silicone adhesive layer

Claims (11)

A laminated film in which a layer A and a layer B are laminated in this order on at least one side of a polymer film,
Both the layers A and B contain a fluorinated silicone resin, the fluorine atom content ratio (atomic number fraction) of the A layer is 50 ppm or more and less than 900,000 ppm, and the fluorine atom content ratio of the B layer (atomic number fraction) is 3,000 ppm or more and 900,000 ppm or less, and a layer B has a higher fluorine atom content than the A layer. 2. The laminated film according to claim 1, wherein the content of fluorine atoms in the B layer is 1.1 times or more the content of fluorine atoms in the A layer. A laminated film in which a layer A and a layer B are laminated in this order on at least one side of a polymer film,
Both the layers A and B contain a fluorinated silicone resin, the fluorine atom content ratio (atomic number fraction) of the A layer is 50 ppm or more and less than 900,000 ppm, and the fluorine atom content ratio of the B layer (atomic number fraction) is 3,000 ppm or more and 900,000 ppm or less,
A laminated film having a normal peel strength of 100 mN/cm or less when measured by the following method.
<Measurement of normal peel strength>
A tape with a silicone pressure-sensitive adhesive (No.5413 tape, 50 mm width, manufactured by 3M Japan Co., Ltd.) is attached to the layer B surface of the laminated film, and a 180° peel test is performed at a peel speed of 0.3 m/min. The laminated film according to any one of Claims 1 to 3, wherein the polymer film is a biaxially stretched polyester film. 5. The laminated film according to claim 1, wherein the layer A has a thickness of 50 nm or more and 1 μm or less, and the layer B has a thickness of 5 nm or more and 1 μm or less. The laminated film according to any one of Claims 1 to 5, wherein the layer A contains a non-fluorinated silicone resin and a fluorinated silicone resin. The laminated film according to any one of claims 1 to 6, wherein the A layer and the B layer are layers formed by curing a curable fluorinated silicone resin. Ratio of fluorine ion (F−) content to methylsiloxane ion (CH ₃ SiO ₂ ⁻ ) content ([F ⁻ ]/ [CH ₃ SiO ₂ ⁻ ]) is 1 or more and 1,000 or less in the A layer, and 3 or more and 5,000 or less in the B layer. A release film using the laminated film according to any one of claims 1 to 8 . A laminate obtained by laminating the release film according to claim 9 and an adhesive layer. 11. The laminate according to claim 10 , wherein a pressure-sensitive adhesive layer is provided on the surface of the B layer that is not in contact with the A layer.

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