CN117447743A

CN117447743A - Laminated film, release film, and laminate

Info

Publication number: CN117447743A
Application number: CN202311249495.7A
Authority: CN
Inventors: 大关阳介
Original assignee: Mitsubishi Chemical Corp
Current assignee: Mitsubishi Chemical Corp
Priority date: 2017-12-11
Filing date: 2018-12-10
Publication date: 2024-01-26
Also published as: KR102639595B1; JPWO2019117059A1; CN111465639A; TW201936390A; WO2019117059A1; JP7173045B2; KR20240005214A; CN111465639B; TWI801466B; KR20200090792A; TW202333953A

Abstract

The present invention provides a laminated film, a release film, and a laminate, each of which has excellent releasability from an adhesive layer having strong adhesion to a silicone adhesive or the like. The laminated film is characterized in that it is a laminated film in which an A layer and a B layer are laminated in this order on at least one side of a polymer film, the two layers of the A layer and the B layer contain fluorine atoms, and the fluorine atom content ratio of the B layer is larger than that of the A layer.

Description

Laminated film, release film, and laminate

The present application is a divisional application of application number 2018800799928, entitled "laminated film, release film, and laminate", having application date 2018, 12, 10.

Technical Field

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

Background

In recent years, automobiles having a liquid crystal panel mounted thereon have been increasing. In such applications for vehicles, there are many cases where the adhesive is exposed to high temperature and low temperature for a long period of time, and high weather resistance and heat resistance are also required for the adhesive for bonding panel constituent members. As an adhesive suitable for these requirements, a strong-adhesion silicone adhesive is attracting attention.

As the silicone adhesive, a material obtained by forming an adhesive layer into a tape (film) is used, and is usually stored in a state of being covered on one or both sides with a release film before use, and the release film is peeled off and used at the time of use. However, the silicone adhesive (adhesive layer) having strong adhesion has a problem that it firmly adheres to a widely used release film coated with an organosilicone and it is difficult to peel the release film at the time of use.

As a method for exhibiting peelability from a molded article formed by molding a molding resin such as a silicone resin composition, a fluorinated silicone material having a fluorine substituent has been proposed (patent document 1).

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2011-201035

Disclosure of Invention

Problems to be solved by the invention

However, when a fluorinated silicone material is used as the release layer, the following problems are observed: the adhesion between the polymer film and the release layer becomes insufficient to cause interlayer peeling, or the release layer is not uniformly formed, and peelability to an adherend is deteriorated.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a release film having excellent releasability from an adhesive layer having strong adhesion such as a silicone adhesive.

Solution for solving the problem

The present inventors have conducted intensive studies to solve the above problems, and as a result, found that: the present invention has been accomplished by solving the above-described problems by providing a polymer film having a layer a and a layer B laminated on at least one surface thereof in this order, each layer of the laminated film containing fluorine atoms, and controlling the ratio of fluorine atoms contained in the two layers.

Specifically, the gist of the present invention is a laminated film comprising a polymer film and, laminated on at least one side thereof, an a layer and a B layer in this order, wherein the two layers of the a layer and the B layer contain fluorine atoms, and the fluorine atom content ratio of the B layer is larger than that of the a layer.

The present invention also provides a laminated film comprising a polymer film and, laminated on at least one side thereof, a layer a and a layer B in this order, wherein the layer B contains fluorine atoms and has a normal peel force of 100mN/cm or less when measured by the following method.

< measurement of normal peel force >

A180 DEG peel test was performed under a condition that a tape (3M tape Limited, no5413 tape, 50mm wide) with a silicone adhesive was applied to the B layer surface of the laminated film, and the peel speed was 0.3M/min.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a laminated film having excellent peelability to an adhesive layer having strong adhesion to a silicone adhesive or the like can be obtained.

Drawings

Fig. 1 is a schematic view of a laminated film of the present invention.

Fig. 2 is a schematic view showing a state of peeling of a silicone adhesive layer in a laminated film of the prior art (a) and the present invention (b).

Detailed Description

Embodiments of the laminated film of the present invention will be described in more detail below.

As illustrated in fig. 1, the laminated film of the present invention is a laminated film in which an a layer (primer layer) and a B layer (release layer) are laminated in this order on at least one side of a polymer film.

The laminated film of the present invention will be described below in order of the polymer film, the a layer (primer layer), and the B layer (release layer).

1. Polymer film

Examples of the polymer film as a substrate of the laminated film of the present invention include films obtained by forming polymers such as polyethylene, polypropylene, polyester, polystyrene, polycarbonate, polyethersulfone, polyamide, and polyimide into a film shape. Further, as long as they can be made into a film, a film (polymer blend) obtained by mixing these materials and a film (copolymer) obtained by compounding structural units may be used.

The polymer film is not particularly limited as long as it is formed into a film, and may be an unstretched film or a stretched film, and is preferably a stretched film stretched in a uniaxial direction or a biaxial direction. Among them, biaxially stretched films are more preferable from the viewpoints 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 can be formed into a film, and is preferably 5 μm or more and 1000 μm or less, more preferably 10 μm or more and 500 μm or less, and still more preferably 15 μm or more and 200 μm or less.

Among the films exemplified above, a biaxially stretched polyester film is particularly preferred because the polyester film is excellent in physical properties such as heat resistance, flatness, optical properties, and strength.

The polyester film may be a single layer or a multilayer film (laminated film) having two or more layers different in property.

In the present invention, the polyester used in the polyester film may be a homo-polyester or a co-polyester. The homo-polyester is preferably a polyester obtained by polycondensing an aromatic dicarboxylic acid with an aliphatic diol. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2, 6-naphthalene dicarboxylic acid, and examples of the aliphatic diol include ethylene glycol, diethylene glycol, 1, 4-butanediol, and 1, 4-cyclohexanedimethanol.

Typical examples of the homopolyester include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT). On the other hand, the dicarboxylic acid component of the copolyester may be one or two or more of isophthalic acid, phthalic acid, terephthalic acid, 2, 6-naphthalene dicarboxylic acid, adipic acid, sebacic acid, and the like, and the diol component may be one or two or more of ethylene glycol, diethylene glycol, propylene glycol, 1, 4-butanediol, 1, 4-cyclohexanedimethanol, neopentyl glycol, and the like.

Among them, in the present invention, it is preferable that: polyethylene terephthalate in which 60 mol% or more, preferably 80 mol% or more, of the polyethylene terephthalate units are usually used.

In the present invention, a primer layer (base coat layer) may be provided on the surface of the polymer film in order to impart antistatic properties, blocking properties by bleeding out a compound or an oligomer (bleeding or plating out) to the surface of the film, or to improve light transmittance of the film and adhesion to a layer a (base coat layer) described later.

The foregoing substrate layer may be formed by any one of: an in-line coating method for forming a substrate layer while forming a polymer film, and an off-line coating method for separately forming a substrate layer on a film that has been formed.

In the case of providing the substrate layer, the substrate layer may be formed on at least one side of the polymer film. When the semiconductor device is formed on both surfaces, the same substrate layer may be formed on both surfaces, or different substrate layers may be formed on the respective surfaces. The substrate layer may be any one of a layer containing an organic substance, a layer containing an inorganic substance, and a layer containing a mixture of an organic substance and an inorganic substance.

Layer A (bottom coating)

In the present invention, the polymer film has an a layer (primer layer) on at least one side.

< constitution of A layer >

The a layer typically contains fluorine atoms. This provides adhesion between the layer a and the layer B described later, and exhibits light peelability between the layer B and the adhesive layer as an adherend when used as a release film, so that the adherend can be easily peeled off.

The method for forming the layer a to contain a fluorine atom is not limited, as long as at least the layer a contains a compound containing a fluorine atom. Specifically, a low molecular compound containing a fluorine atom, a resin containing a fluorine atom, and the like are exemplified. Among them, a resin containing fluorine atoms is preferably used, and the resin is particularly preferably curable.

Further, when used as a release film, the release film can be made light in release force against an adherend by laminating the layer B on the layer a. According to the presumption of the present inventors: when the layer a is not laminated on the laminated film, the adherend (adhesive) also follows in the peeling direction when the laminated film is peeled off, and therefore a larger force is required to peel off the adherend, and peeling (re-peeling) is difficult (fig. 2 (a)). On the other hand, as shown in the present invention, it can be presumed that: when the layer a containing fluorine atoms is laminated on the laminated film, the layer a is relatively flexible, and therefore, the layer a functions as a buffer at the time of peeling, and deformation of the adherend is suppressed, so that the adherend can be peeled off with a smaller force, and peeling (light peeling) is easy (fig. 2 (b)).

< fluorine atom content ratio of layer A >

The layer a contains a material containing fluorine atoms, and from the viewpoints of adhesion and light releasability, the fluorine atom content (atomic fraction) is preferably 50ppm or more, more preferably 500ppm or more, still more preferably 1000ppm or more, and particularly preferably 50000ppm or more, based on the entire layer a. On the other hand, the upper limit is not particularly limited, but is preferably less than 900000ppm, more preferably not more than 800000ppm, and still more preferably not more than 700000 ppm.

The fluorine atom content of the a layer can be confirmed by, for example, performing depth direction analysis by sputter etching in the vicinity of the polymer thin film and the primer layer constituting the laminated thin film by using X-ray photoelectron spectroscopy (XPS method). The fluorine atom content of the layer a may be quantified by using a material (fluorinated silicone or the like) whose fluorine atom content is known in advance as a reference. When confirmed by the XPS method, the fluorine atom content ratio is defined as the ratio of fluorine to all elements except hydrogen and helium.

When the fluorine atom content ratio of the layer a is set to the above range, the layer B (release layer) containing fluorine atoms can be uniformly coated on the layer a by the coating method, and adhesion between the coated and laminated layer a and layer B can be improved.

The resin used for the layer a may be a resin containing fluorine atoms alone or in combination with a resin (non-fluorinated resin) containing no fluorine atoms, as long as the fluorine atom content ratio is obtained in the entire layer a.

The layer a may have a composition in which the fluorine atom content ratio is inclined in the thickness direction. The same applies to layer B described below.

< resin containing fluorine atom >

The resin containing fluorine atoms used in the present invention includes resins containing fluorine atoms in side chain portions of a resin skeleton. Specific examples of the resin containing fluorine atoms include fluorocarbon resins such as polytetrafluoroethylene and other fluorinated resins, and among these, fluorinated silicone resins are preferable from the viewpoint of releasability.

The fluorinated silicone resin may be a curable resin or a non-curable resin, and may be used without particular limitation. Among them, curable fluorinated silicone resins are preferred from the point of forming a stronger layer. The fluorinated silicone resin may be a solvent-based resin, a solvent-free resin, or a resin obtained by mixing them. The curable fluorinated silicone resin is generally bonded with a functional group capable of forming a crosslinked structure by reaction (curing), such as an alkenyl group or a hydrosilyl group.

Examples of the curable fluorinated silicone resin include KP-911 and X-70-201S manufactured by Xinyue Chemicals; dow Corning Toray Co., ltd. FS1265-300CS, FS1265-1000CS, FS1265-10000CS, BY24-900, BY24-903, syl-off 3062, Q2-7785, etc.

The fluorine atom content (atomic fraction) of the fluorinated silicone resin is usually about several thousand ppm to several tens%.

< resin containing no fluorine atom >

Among these, a resin containing fluorine atoms is preferable, and a silicone resin is particularly preferable from the standpoint of compatibility with a fluorinated silicone resin (in the present invention, a silicone resin containing no fluorine atoms is sometimes referred to as a "non-fluorinated silicone resin"). The non-fluorinated resin may be either a curable resin or a non-curable resin, or both may be used in combination. Similar to the curable fluorinated silicone resin, the non-curable fluorinated silicone resin is generally bonded with a functional group such as an alkenyl group or a hydrosilyl group, which can form a crosslinked structure by reaction (curing).

Curable non-fluorinated silicone resin

The curable non-fluorinated silicone resin may be a solvent type or a solvent-free type.

Specific examples of curable non-fluorinated silicone resins include KNS-3051, KNS-320-A, KNS-316, KNS-3002, KNS-3300, X-62-1387, KS-3656, KS-837, X-62-2829, KS-3650, 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, and 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, LTC761, LTC856, LTC851, etc.

Further, a heavy release additive may be added to the curable non-fluorinated silicone resin, and examples thereof include KS-3800 manufactured by Xinyue chemical Co., ltd; SD7292, BY24-4980, manufactured BY Dow Corning Toray Co., ltd.

The curable non-fluorinated silicone may be used alone or two or more of the above-mentioned curable non-fluorinated silicones may be used in combination. By mixing two or more kinds of curable non-fluorinated silicones, the curing reaction or the viscosity of the coating liquid for the layer a can be adjusted, or the wettability and reactivity of the layer B can be further improved. In this case, the solvent-free silicones may be mixed with each other, or the solvent-free silicones and the solvent-free silicones may be mixed with each other. In particular, when the film thickness of the a layer is increased to further obtain a release film that is slightly peeled, the concentration of the solid content of the coating liquid for forming the a layer tends to be high. Therefore, there is a possibility that the viscosity of the coating liquid increases, the coating appearance deteriorates, and the thickness unevenness increases. Therefore, by mixing the solvent-free silicone and the solvent-based silicone, the viscosity of the coating liquid can be reduced, and an a layer having a good coating appearance and small thickness variation can be formed.

Here, the "solvent-free silicone" is a silicone having a viscosity that can be applied without dilution with a solvent, is formed of a short polysiloxane chain, and has a relatively low molecular weight.

The viscosity of the solvent-free silicone is preferably less than 1000mpa·s, more preferably 50mpa·s or more or 900mpa·s or less, and even more preferably 80mpa·s or more or 800mpa·s or less, based on the viscosity at 100% concentration.

On the other hand, "solvent-based silicone" is silicone having a viscosity up to such an extent that it cannot be applied without dilution with a solvent, and is silicone containing a relatively high molecular weight.

Regarding the viscosity of the solvent silicone, the viscosity at the time of preparing a 30% toluene solution is preferably 1000mpa·s or more, more preferably 2000mpa·s or more or 20000mpa·s or less, and further preferably 3000mpa·s or more or 18000mpa·s or less.

Non-curable non-fluorinated silicone resin

By including the non-curable non-fluorinated silicone resin in the layer a, the controllability of the curing reaction can be improved, sufficient flexibility can be imparted to the layer a, and the storage stability of the laminate in which the laminate film and the adhesive layer are laminated can be improved. As the non-curable non-fluorinated silicone resin, the silicone resin which is the non-fluorinated silicone resin listed above and has no reactive functional group can be used without particular limitation. Specifically, an organopolysiloxane represented by the following general formula (I) is preferable.

R ₃ SiO(R ₂ SiO) _m SiR ₃ ……(I)

(wherein R represents a monovalent hydrocarbon group of the same or different kinds having no aliphatic unsaturated bond, and m represents a positive integer.)

The mixing ratio by mass of the curable silicone resin (sum of fluorinated and nonfluorinated) to the non-curable nonfluorinated silicone resin is preferably 1: 1000-1000: 1, more preferably in the range of 1: 100-100: within the range of 1, further preferably within 1: 50-50: 1. Particularly preferably in the range of 1: 20-20: within the range of 1, 1 is particularly preferred: 1-20: 1.

the film thickness of the layer A is preferably 10nm to 100. Mu.m, more preferably 20nm to 10. Mu.m, still more preferably 50nm to 1. Mu.m. Particularly preferred ranges are 80nm to 800 nm.

When the film thickness is too small as less than 10nm, not only the adhesion between the a layer and the B layer but also the peelability between the silicone adhesive layer and the B layer of the laminated film tends to be deteriorated. On the other hand, when the film thickness of the a layer is too large, the amount of the material increases, and it is difficult to obtain an increase in effect corresponding to the increase in the amount.

Layer B (Release layer)

< construction of layer B >

As a material for forming the B layer (release layer), the same resin containing fluorine atoms as described for the above-described a layer (primer layer) can be used in the same manner. Among them, from the viewpoint of releasability from an adherend, fluorinated silicone resins are preferable, and curable fluorinated silicone resins are particularly preferable. By using a curable fluorinated silicone resin for the B layer (release layer), a release film having stable releasability from the silicone adhesive layer can be obtained.

The layer B may be formed of a curable fluorinated silicone resin alone, or a mixture of a plurality of materials such as a mixture with a curable non-fluorinated silicone resin may be used.

The coating liquid for forming the B layer preferably contains a fluorine-based solvent containing a fluorine atom for the purpose of improving wettability to the a layer.

If the film thickness of the B layer is too small, the effect of the present invention may be difficult to obtain, whereas if it is too thick, it may be difficult to obtain an increase in effect in accordance with the increase in the amount of the material used.

The lower limit of the film thickness of the layer B is preferably 5nm or more, more preferably 10nm or more, and particularly preferably 20nm or more. The upper limit is preferably 50 μm or less, more preferably 1 μm or less, and particularly preferably 500nm or less.

< fluorine atom content ratio of layer B >

The laminated film of the present invention has a layer B (release layer) formed on the layer a (primer layer). The material suitable for the layer B is the same as that described in the description of the layer a, but from the viewpoints of adhesion and light releasability, the fluorine atom content per unit volume in the layer B must be more than that in the layer a.

In the present invention, the lower limit of the fluorine atom content ratio (atomic fraction) contained in the B layer measured by SIMS method or the like is preferably 3000ppm or more, more preferably 5000ppm or more, still more preferably 10000ppm or more, particularly preferably 20000ppm or more. On the other hand, the upper limit is not particularly limited, but is preferably 900000ppm or less, more preferably 800000ppm or less, and particularly preferably 700000ppm or less.

The fluorine atom content of the B layer can be confirmed on the release layer surface of the laminated film by, for example, secondary ion mass spectrometry (SIMS method) or X-ray photoelectron spectroscopy (XPS method). The fluorine atom content of the B layer may be quantified by using a material (fluorinated silicone or the like) whose fluorine atom content is known in advance as a reference. When confirmed by the XPS method, the fluorine atom content ratio is defined as the ratio of fluorine to all elements except hydrogen and helium.

While the case where the a layer and the B layer having different fluorine atom content ratios are laminated in this order has been described above, in one lamination step, the fluorine atom content ratio in the layer may be processed so as to have an inclined structure (form an inclined composition) in the thickness direction, and thus may have a structure substantially equivalent to the laminated structure of the a layer and the B layer. For example, the following methods are mentioned: a method in which a fluorine atom-containing resin and a fluorine atom-free resin are diluted with a solvent to prepare a coating liquid, and the coating liquid is applied to at least one side of a polymer film and dried, whereby the fluorine atom-containing resin is concentrated on the surface of the layer to prepare a layer having an inclined structure in the thickness direction. In the case of using such a lamination step, the means for laminating the a layer and the B layer in sequence stepwise is not necessarily limited, and the interface between the two layers may not be obvious, and the present invention is also included as long as the surface side of one layer is the B layer and the polymer film side is the a layer and substantially has the same structure.

By forming the layer a and the layer B in an inclined structure in this manner, it is also expected to improve the adhesion of the interface between the substantial layer a and the polymer film and the interface between the layer a and the layer B. Further, since the fluorine atom content ratio of the B layer surface can be increased, the content of the fluorine atom-containing resin in the entire laminated film may be suppressed to be low, and the light peelability may be further improved.

4. Fluorine atom content ratio

In the present invention, from the viewpoints of adhesion and light releasability, the two layers of the layer a and the layer B contain fluorine atoms in a proportion to the methyl siloxane ion (CH ₃ SiO ₂ ^- ) The content ratio of (2) is preferably in a specific relationship.

That is, the ratio of the fluorine ion content to the methyl siloxane ion content ([ F) of the layer B calculated by the SIMS method or the like ^- ]/[CH ₃ SiO ₂ ^- ]) (hereinafter abbreviated as "fluorine atom content ratio") is preferably larger than the fluorine atom content ratio of the layer A.

The fluorine atom content ratio of each of the a layer and the B layer is preferably 1 to 1000, and the B layer is preferably 3 to 5000.

The lower limit of the fluorine atom content ratio of the layer B is preferably 5 or more, more preferably 10 or more, and still more preferably 20 or more. The upper limit is preferably 3000 or less, more preferably 1000 or less.

From the viewpoint of light releasability from the silicone adhesive layer, the fluorine atom content ratio of the B layer is preferably 1.1 times or more, more preferably 1.5 times or more, still more preferably 2 times or more, particularly preferably 3 times or more, and most preferably 5 times or more the fluorine atom content ratio of the a layer. On the other hand, the upper limit is not particularly limited, but is preferably 1000 times or less, more preferably 100 times or less, from the viewpoint of adhesion between the a layer and the B layer.

In the present invention, the fluorine atom content ratio (atomic number fraction) in the B layer is preferably 1.1 times or more, more preferably 1.5 times or more, still more preferably 2 times or more, particularly preferably 3 times or more, and most preferably 5 times or more the fluorine atom content ratio (atomic number fraction) in the a layer from the viewpoint of light releasability from the silicone adhesive layer. On the other hand, the upper limit is not particularly limited, but is preferably 1000 times or less, more preferably 100 times or less, from the viewpoint of adhesion between the a layer and the B layer.

Here, "fluorine atom content ratio (atomic fraction)" means the ratio of fluorine atoms to the layer. When the layers a and B are each substantially composed of a silicone resin (including fluorinated, nonfluorinated, curable, and non-curable), the ratio of the layers a and B is the same as the ratio of the fluorine atoms in the above-mentioned "fluorine atom content ratio" and "fluorine atom content ratio (atomic fraction)".

By setting the fluorine atom content ratio of the B layer to the above range, sufficient adhesion between the a layer and the B layer can be obtained, and good peelability of the B layer from the silicone adhesive layer can be exhibited.

Further, by setting the fluorine atom content ratio and/or the fluorine atom content ratio of the B layer to be higher than those of the a layer, sufficient adhesion between the a layer and the B layer can be obtained, and good peelability between the B layer and the silicone adhesive layer can be stably exhibited.

The fluorine atom content ratio or fluorine atom content ratio of the a layer and the B layer may be calculated by analyzing the structure thereof by nuclear magnetic resonance spectroscopy (NMR) of the coating agent, or may be determined by Secondary Ion Mass Spectrometry (SIMS) or X-ray electron spectroscopy (XPS) after the formation of the layers.

In the measurement by the SIMS method or XPS method, the fluorine atom content of each layer may be quantified based on a material (fluorinated silicone or the like) whose fluorine atom content is known in advance.

When fluorine atoms are not uniformly present in each of the a layer and the B layer (for example, in the case of the above-described oblique structure), the fluorine atom content ratio per unit volume obtained by dividing the total amount of fluorine atoms contained in each layer by the volume of each layer, as measured by SIMS method or the like, may be defined 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 having the curable non-fluorinated silicone resin and the curable fluorinated silicone resin preferably contains a crosslinking agent, a catalyst, and a reaction initiator (reaction accelerator). Commercially available paints containing curable silicone resins may contain a crosslinking agent and a catalyst from the beginning.

In forming the layer a and the layer B, a crosslinking agent is preferably contained so as to react with the reactive functional group contained in the resin to form a crosslinked structure. Examples of the crosslinking agent include vinyl siloxane and organosiloxane having a hydrosiloxane moiety. Specific examples of the crosslinking agent include Dow Corning Toray co., ltd. SP7297, 7560, 3062A, 3062B, 3062C, 3062D, and the like.

The crosslinking agent may contain a moiety having a fluorine substituent, or a silane coupling agent having a fluorinated substituent may be used.

Further, in forming the layer a and the layer B, a catalyst that promotes an addition reaction is preferably contained, and among them, a platinum catalyst is preferably contained. Examples of the platinum catalyst include platinum-based compounds such as chloroplatinic acid, an alcohol solution of chloroplatinic acid, a complex of chloroplatinic acid and an olefin, and a complex of chloroplatinic acid and an alkenylsiloxane; platinum black, platinum-supporting silica, and platinum-supporting activated carbon. The platinum catalyst may be used in an amount of 1 or 2 or more in combination.

Specific examples of the catalyst include CAT PL-50T, dow Corning Toray Co, manufactured by Xinyue chemical Co., ltd., SRX212P, NC-25, and FS XK-3077.

Examples of other additives that can be blended in the a layer and the B layer include alkyl (meth) acrylates having 1 to 20 carbon atoms in the ester group, acrylic resins, olefin resins, and the like. Among them, preferred is a silane coupling agent having a fluorinated substituent.

5. Physical Properties of the laminated film of the present invention

< normal peel force >

The normal peel force of the laminate film of the present invention is preferably 100mN/cm or less.

When the laminated film is used as a release film, the lower the normal peeling force, the less force is required to peel the self-adhesive layer. Therefore, the release film can be peeled from the laminate in which the adhesive layers are laminated, and defects such as peeling failure and deformation of the adhesive layers in the production process of attaching the adhesive layers to various members can be suppressed. Among these, the laminated film of the present invention has low peelability, while suppressing the above-described drawbacks even when it is an adhesive layer having strong adhesion such as a silicone adhesive. In addition, as the release film, the release film on the undesired side can be prevented from peeling in the laminate having the release films on both sides of the adhesive layer.

From this viewpoint, the normal peel force is preferably 70mN/cm or less, more preferably 40mN/cm or less, particularly preferably 35mN/cm or less, and most preferably 30mN/cm or less. On the other hand, the lower limit is not particularly limited, but is preferably 1mN/cm or more, more preferably 3mN/cm or more, from the viewpoint of storage stability of the laminate in which the laminate film and the adhesive layer are laminated.

Examples of the method for reducing the normal peel force include a method for adjusting the fluorine atom content ratio of the layer a and the layer B. The normal peel force was measured by the method described in examples below.

6. Laminated structure

The laminated film of the present invention may have a structure in which the a layer is provided on one side or both sides of the polymer film and the B layer is provided on the a layer. Other layers may be interposed between the polymer film and the layer a and between the layer a and the layer B, as required.

Examples of the other layer include an antistatic layer having antistatic properties, and an oligomer blocking layer for blocking oozing (bleeding or precipitation) of the compound or oligomer to the surface of the film.

The antistatic layer, the oligomer blocking layer, and the like may be formed by either an in-line coating method in which a polymer film is formed by film formation or an off-line coating method in which a polymer film is formed by a separate process.

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

7. The method for producing a laminated film of the present invention

< manufacturing method >

(1) Polymer film

As the polymer film as a base material of the laminated film of the present invention, as described above, a film obtained by forming polyethylene, polypropylene, polyester, polystyrene, polycarbonate, and other polymer materials into a film shape can be used.

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, the following method is preferable: using the polyester raw material such as polyethylene terephthalate, the molten sheet extruded from the die is cooled and solidified by a cooling roll to obtain an unstretched sheet. In this case, in order to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the rotating cooling drum by an electrostatic application encryption method and/or a liquid coating sealing method.

The resulting unstretched sheet may be used as it is, but is preferably subjected to at least uniaxial stretching, more preferably biaxial stretching. By stretching the polyester film uniaxially or more, good mechanical strength and dimensional stability can be obtained. In addition, when the adhesive sheet with a laminated film is produced by laminating an adherend (adhesive layer) in the case of using the adhesive sheet as a release film, occurrence of a defect in lamination can be suppressed.

The stretching conditions are not particularly limited either, and for example, a biaxially stretched polyester film is obtained by stretching an unstretched sheet to 2 to 6 times at 70 to 145 ℃ in the longitudinal direction (machine direction) by a roll stretching method, then stretching to 2 to 6 times at 80 to 160 ℃ in the direction perpendicular to the previous stretching direction (width direction) by a tenter, and further heat-treating at 150 to 250 ℃ for 1 to 600 seconds.

In this case, the following method is more preferable: in the heat treatment zone and/or the cooling zone of the heat treatment outlet, 0.1 to 20% of the relaxation is made in the longitudinal direction and/or the width direction.

(2) Formation of layer A (primer layer) and layer B (release layer)

The method for forming the a layer and the B layer is not limited, and may be formed by a coextrusion method or the like, but a coating method is preferable.

The number of applications of the layers a and B may be 1 or 2 or more. When the number of coating times is 2 or more to form the a layer and the B layer, different coating liquids may be applied. Wherein at least any of the coating liquids must contain fluorine atoms.

The coating method may be either in-line coating or off-line coating, and may use a coating technique such as that shown in "coating method" (original kiku, bookstore, 1979).

Examples of the coating head include a gas knife coater, a blade coater, a bar coater, a blade coater, an extrusion coater, an impregnation coater, a reverse roll coater, a transfer roll coater, a gravure coater, a roll lick coater, a casting coater, a spray coater, a curtain coater, a calender coater, and an extrusion coater.

The solid content mass concentration of the coating liquid for forming the a layer and the B layer is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, and still more preferably 0.1 mass% or more. On the other hand, the upper limit is preferably 90 mass% or less, more preferably 50 mass% or less, and particularly preferably 20 mass% or less.

The solvent used for dilution may be a polar solvent or a nonpolar solvent. In addition, a fluorine solvent having a fluorine atom may be used. Further, 2 or more solvents may be used in combination. In particular, in the coating liquid for forming the B layer, a fluorine solvent having a fluorine atom is preferably contained for the purpose of improving wettability with respect to the a layer.

Examples of the polar solvent 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, and diisobutyl ketone; glycols such as ethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether; n-methyl-2-pyrrolidone, N-dimethylformamide, tetrahydrofuran, acetonitrile, and the like.

Examples of the nonpolar solvent include aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as hexane, heptane, octane, etc.; hydrocarbons having a branched structure such as isohexane, isooctane and isononane; alicyclic hydrocarbons such as cyclohexane, cycloheptane and cyclooctane; dioxane, and the like. Examples of the fluorine solvent include hydrofluoroethers, m-bis (trifluoromethyl) benzene, tridecyl octane, and the like.

As a method for forming these layers, the following method can be exemplified: as the coating liquid, a coating liquid having a fluorine atom content equivalent to that of each layer after coating/drying was prepared in advance and used.

Further, by using a curable non-fluorinated silicone resin, a coating liquid having a composition corresponding to that of the a layer/B layer is prepared by mixing the curable non-fluorinated silicone resin with a fluorinated material in a predetermined amount, and coating/drying is performed on the resultant mixture, whereby a desired a layer and/or B layer containing fluorine atoms can be formed. This method is preferable because it can more easily produce a release film having an a layer/B layer with a specific fluorine atom content ratio.

The a layer and the B layer may be formed by coating the a layer and drying the B layer, and then coating the B layer and drying the B layer.

As other methods, there are the following: the method is more preferable because it can stably produce a release film, since it is preferable to apply a mixture of a curable fluorinated silicone resin and a curable non-fluorinated silicone resin to form a layer a and then apply a solution containing a curable fluorinated silicone resin as a main component to form a layer B.

Further, as another method, a non-fluorinated resin may be formed in advance by coating, and thereafter, a carbon tetrafluoride (CF ₄ ) A dry process such as plasma treatment to produce a fluorinated layer. Wherein the method requires the provision of a chamber for plasma processing, and therefore,it can be said that the method is suitable for mass production.

In the case of using so-called in-line coating in which coating is performed in the step of producing a polymer film, the method for producing a laminated film of the present invention may be carried out by in-line coating of both the a layer and the B layer, or may be carried out by in-line coating of only the a layer and off-line coating of the B layer.

When the layers a and B are both provided by off-line coating, they may be formed continuously by 1 "substrate film roll-out and roll-up process", or may be formed sequentially by a plurality of "substrate film roll-out and roll-up processes", the former method being simple in manufacturing process and capable of manufacturing at a lower cost, and thus being a particularly preferable method.

Further, it is preferable that the amount of heat applied to the film when the layer a is formed is smaller than the amount of heat applied when the layer B is formed, because deterioration in the flatness of the film when the layer B is formed can be suppressed, and uneven coating of the layer B can be effectively prevented.

8. Method for using laminated film

The laminated film of the present invention has excellent releasability, and therefore can be provided as, for example, an adhesive sheet with a laminated film having a structure in which the laminated film and the adhesive layer are laminated. In particular, the laminated film of the present invention has excellent releasability even with respect to a silicone adhesive having strong adhesion, and therefore can be provided as, for example, an adhesive sheet with a laminated film having a structure in which the aforementioned laminated film and an adhesive layer formed of a silicone adhesive are laminated.

The method of using the laminated film is not limited to the above method. For example, since the laminated film contains fluorine atoms, the laminated film is excellent in water resistance, water repellency, oil resistance, oil repellency, antifogging property, antifouling property, chemical resistance, corrosion resistance, and the like, and thus, printed boards, optical member protective films, films for building materials, agricultural films, highly water repellent films, films for packaging, cosmetic films, surface protective films, and the like can be cited. When the surface of the layer B is used as the outermost surface, an adhesive layer, a heat seal layer, or the like may be provided on the surface of the polymer film opposite to the surface having the layer a and the layer B.

< Silicone adhesive >

Examples of the silicone adhesive include addition reaction type, peroxide curing type, and condensation reaction type silicone adhesives. Among them, from the viewpoint of being capable of curing at a low temperature in a short time, addition reaction type silicone adhesives are preferably used. These addition reaction type silicone adhesives cure when an adhesive layer is formed on a support.

When an addition reaction type silicone adhesive is used as the silicone adhesive, the silicone adhesive may contain a catalyst such as a platinum catalyst.

For example, the aforementioned addition reaction type silicone adhesive may be cured as needed in the following manner: a catalyst such as a platinum catalyst is added to a silicone resin solution diluted with a solvent such as toluene, and the mixture is stirred until uniform, and then applied to a support, and cured at 100 to 130 ℃/1 to 5 minutes.

Further, a crosslinking agent, an additive for controlling the adhesive force, or a primer treatment may be applied to the support before the adhesive layer is formed, if necessary, to the addition reaction type silicone adhesive.

Examples of the commercially available silicone resins used in the addition reaction type silicone ADHESIVE include SD4580PSA, SD4584PSA, SD4585PSA, SD4587LPSA, SD4560PSA, SD4570PSA, SD4600FCPSA, SD4593PSA, DC7651 adhese, DC7652 adhese, LTC-755, LTC-310 (all Dow Corning Toray co., ltd.); 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 (all made by Xinyue chemical Co., ltd.); AS-PSA001, AS-PSA002, AS-PSA003, AS-PSA004, AS-PSA005, AS-PSA012, AS-PSA014, and PSA-7465 (all manufactured by Deskan chemical Co., ltd.); TSR1512, TSR1516, TSR1521 (manufactured by Inc. of Momentive Performance Materials), and the like.

Examples

The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to the following examples. In the following examples, the raw materials denoted as "addition type" are all referred to as "curability".

(1) Evaluation method

(1-1) Normal Peel force

A tape (3M tape Limited, no5413 tape, 50mm wide) with a silicone adhesive was attached to the surface of the B layer (release layer) of the laminated film at 23℃and placed in a peel tester. The normal peel force was measured at a peel speed of 0.3 m/min and a peel angle of 180 °.

(1-2) ratio of the fluorine atom content to the fluorine atom content

The fluorine atom content ratio in the A layer and the B layer was evaluated by TOF-SIMS (ULVAC-PHI, inc. manufactured by TRIF V).

Au was used as the primary ion ³⁺ The acceleration voltage was set at 30kV.

To evaluate the fluorine atom content ratio per unit volume, etching with Ar gas (voltage: 5kV, current: 2nA, etching rate: 20 nm/min (in terms of PET film)) was performed for 0 min, 1 min, 2 min, 3 min, and anions ("F") detected at each etching time were measured ^- "and" CH ₃ SiO ₂ ^- ") is averaged and used as the fluorine atom content ratio per unit volume (" F) ^- ”/“CH ₃ SiO ₂ ^- ”)。

The value of [ the fluorine atom content ratio of layer B ]/[ the fluorine atom content ratio of layer A ] is set as the ratio of the fluorine atom content ratio. This value has the same meaning as the result obtained by measuring the fluorine atom content ratio (atomic number fraction) of each of the a layer and the B layer using XPS and calculating the ratio of the values of the respective layers.

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 became 4 mass%, to prepare "coating liquid 1".

< coating liquid 1 composition >

Addition of an organic silicone (KS-847, made by Xinyue chemical Co., ltd.): 67 parts by mass

Platinum catalyst (CAT-PL-50T, made by Xinyue chemical Co., ltd.): 0.7 part by mass

Addition fluorinated silicone (Dow Corning Toray co., ltd., sy-off 3062): 100 parts by mass

Crosslinking agent (Dow Corning Toray co., ltd., sy-off 3062A): 0.5 part by mass of a platinum catalyst (Dow Corning Toray co., ltd., FSXK-3077): 0.5 part by mass

(coating liquid 2)

The following compositions were mixed and FS diluent (believed to be chemical company)/ethyl acetate=1: 1 (mass ratio) was diluted so that the solid content concentration became 0.5 mass%, to prepare "coating liquid 2".

< coating liquid 2 composition >

Fluorinated silicone (X-70-201S, made by singe chemical Co., ltd.): 100 parts by mass

Platinum catalyst (CAT-PL-50T, made by Xinyue chemical Co., ltd.): 0.5 part by mass

(production of laminated film)

A PET film (T100-38, 38 μm thick, manufactured by Mitsubishi chemical corporation) was used as the polymer film, the coating liquid 1 was applied to the polymer film by a bar coater (No. 4 bar), and the resin of the layer A was cured by drying it in a dryer at 150℃for 30 seconds, thereby producing a polymer film having a layer A (primer layer).

The coating liquid 2 was further applied onto the layer a of the polymer film having the layer a (primer layer) by a bar coater (No 4 bar), and the resin of the layer B was cured by drying it in a dryer at 150 ℃ for 30 seconds, thereby producing a laminated film having the layer B (release layer) on the layer a (primer layer).

Example 2

A laminated film was produced in the same manner as in example 1, except that the solid content concentration of the coating liquid 2 was set to 4 mass%.

Since the coating liquid 2 was applied using the same bar coater as in example 1, the thickness of the B layer was increased as compared with example 1 by increasing the solid content concentration.

Comparative example 1

A laminated film consisting essentially of only a polymer film and a B layer (release layer) was produced in the same manner as in example 1, except that the polymer film was not provided with the a layer (primer layer) and only the coating liquid 2 was applied by a bar coater (No 4 bar).

Comparative example 2

A laminated film was produced in the same manner as in comparative example 1, except that the solid content concentration of the coating liquid 2 was set to 4 mass%.

Since the coating liquid 2 was applied using the same bar coater as in comparative example 1, the thickness of the B layer was increased as compared with comparative example 1 by increasing the solid content concentration.

Comparative example 3

A laminated film consisting essentially of only a polymer film and an a layer (primer layer) was produced in the same manner as in example 1, except that the coating liquid 2 was not applied to the a layer (primer layer) and a B layer (release layer) was not formed.

Comparative example 4

(coating liquid 3)

Coating liquid 3 was prepared according to the following composition.

< coating liquid 3 composition >

Addition of an organic silicone (KS-847H, made by Xinyue chemical Co., ltd.): 67 parts by mass

The above composition was diluted with a mixed solvent of n-hexane and MEK (mass ratio=1:1) so that the solid content concentration became 4 mass%.

(production of laminated film)

The coating liquid 3 was applied to the polymer film by a bar coater (No. 4 bar), and dried in a dryer at 150℃for 30 seconds, whereby a layer A (primer layer) was provided.

Next, the coating liquid 2 was applied onto the a layer (primer layer) by a bar coater (No 4 bar). However, the coating liquid 2 was not uniformly applied to the a layer (primer layer), and a phenomenon (repulsion) of dot or line shape (lattice shape) occurred, so that the B layer (release layer) could not be formed.

Comparative example 5

A laminated film was produced in the same manner as in comparative example 4 except that the solid content concentration of the coating liquid 2 was set to 4 mass% for the layer B (release layer). However, the "coating liquid 2" was not uniformly applied to the layer a (primer layer), and a phenomenon (repulsion) of dot-like or linear shape (lattice shape) occurred, and thus the layer B (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 became 4 mass%, to prepare "coating liquid 4".

< coating liquid 4 composition >

Addition of an organic silicone (KS-847, made by Xinyue chemical Co., ltd.): 133 parts by mass

Platinum catalyst (CAT-PL-50T, made by Xinyue chemical Co., ltd.): 1.3 parts by mass

Crosslinking agent (Dow Corning Toray co., ltd., sy-off 3062A): 0.5 part by mass

Platinum catalyst (Dow Corning Toray co., ltd., FSXK-3077): 0.5 part by mass

(production of laminated film)

A laminated film was produced in the same manner as in example 1, except that the coating liquid 4 was applied to the polymer film instead of the coating liquid 1 and cured, and the coating liquid 2 diluted so that the solid content concentration became 2 mass% was applied to the a layer (primer layer) thus obtained.

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 became 4 mass%, to prepare "coating liquid 5".

< coating liquid 5 composition >

Addition of an organic silicone (KS-847, made by Xinyue chemical Co., ltd.): 200 parts by mass

Platinum catalyst (CAT-PL-50T, made by Xinyue chemical Co., ltd.): 2.0 parts by mass

(production of laminated film)

A laminated film was produced in the same manner as in example 3, except that the coating liquid 5 was applied to the polymer film instead of the coating liquid 4 to form an a layer (primer 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 became 4 mass%, to prepare "coating liquid 6".

< coating liquid 6 composition >

Addition of an organic silicone (KS-847, made by Xinyue chemical Co., ltd.): 267 parts by mass

(production of laminated film)

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

(3) Evaluation of results

The fluorine atom content ratio of the layer a (primer layer) and the layer B (release layer) was measured for the obtained laminated film, and the normal peel force of the silicone adhesive tape was measured. The results are shown in table 1 below.

It can be seen that: in examples 1 and 2, since the layer a (primer layer) and the layer B (release layer) specified in the present invention were formed on the PET film, good peelability was obtained as compared with comparative examples 1 and 2 obtained using a film having only the layer B (release layer).

In particular, the laminated film of example 1 was formed to be thinner (the concentration of the coating liquid 2 was "0.5 mass%") but still had the same level of peelability as the release film of example 2 (the concentration of the coating liquid 2 was "4 mass%") in which the B layer (the release layer) was thicker than that of example 1. From this, it was determined that a release film having excellent releasability from a silicone adhesive can be produced using a smaller amount of a fluorine-based material.

Furthermore, it is determined that: the release films of examples 3 to 5, in which the fluorine atom content ratio of the a layer (primer layer) was smaller than that of example 1, also obtained release films having the same level of peelability as the release film of example 1, and release films having excellent peelability to silicone adhesives could be produced using a smaller amount of fluorine-based material.

In order to evaluate the fluorine atom content ratio of each layer, the fluorine atom content ratio by TOF-SIMS was measured as the value of each of the A layer and the B layer for the samples of comparative example 3 (A layer only) and comparative example 2 (B layer only). As a result, it was confirmed that the fluorine atom content per unit volume of the B layer was larger than that of the a layer.

Since the coating liquids had the same composition, the fluorine atom content ratio of each layer in examples 1 and 2 and comparative example 1 was set to be the value. The fluorine atom content ratio of the a layer in examples 3 to 5 was calculated from the raw material composition ratio based on the value of the fluorine atom content ratio in example 1.

Note that, it can be considered that: the fluorine atom content ratio of the a layer is largest on the surface (etching time of 0 minutes in TOF-SIMS), and the longer the etching time (that is, the closer to the substrate PET film side), the smaller the etching time becomes, and an inclined structure having an increased fluorine atom content ratio on the surface side can be formed. The values shown in table 1 are average values in the thickness direction.

TABLE 1

Description of the reference numerals

1. Polymer film

2A layer (bottom coating)

3B layer (Release layer)

4. Silicone adhesive layer

Claims

1. A laminated film comprising a polymer film and, laminated on at least one side thereof, an A layer and a B layer in this order,

The two layers of the layer A and the layer B contain fluorine atoms, and the fluorine atom content ratio of the layer B is larger than that of the layer A.

2. The laminated film according to claim 1, wherein the content ratio of fluorine atoms in the B layer is 1.1 times or more with respect to the content ratio of fluorine atoms in the a layer.

3. A laminated film comprising a polymer film and, laminated on at least one side thereof, an A layer and a B layer in this order,

the layer B contains fluorine atoms, and has a normal peel force of 100mN/cm or less when measured by the following method,

determination of normal peel force:

a180 DEG peel test was performed by bonding a tape with a silicone adhesive, which was 3M tape Limited, no5413 tape, and 50mm wide, to the surface of the B layer of the laminated film at a peel speed of 0.3M/min.

4. 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 a layer and the B layer contain fluorinated silicone resin.

6. The laminated film according to claim 1, wherein the a layer contains a non-fluorinated silicone resin and a fluorinated silicone resin.

7. The laminated film according to claim 1, wherein the a layer and the B layer are layers formed by curing a curable fluorinated silicone resin.

8. The laminated film according to claim 5, wherein the fluorine ion (F ^- ) The content ratio of the methyl siloxane ion (CH) ₃ SiO ₂ ^- ) Ratio of content ([ F) ^- ]/[CH ₃ SiO ₂ ^- ]) Layer A is 1 to 1000, layer B is 3 to 5000.

9. The laminated film according to claim 1, wherein the fluorine atom content ratio of the layer A is 50ppm or more and less than 900000ppm, and the fluorine atom content ratio of the layer B is 3000ppm or more and 900000ppm or less.

10. A release film using the laminated film according to any one of claims 1 to 9.

11. A laminate comprising the release film according to claim 10 and an adhesive layer.

12. The laminate according to claim 11, wherein an adhesive layer is provided on a surface of the B layer on a side not in contact with the a layer.