Laminated film and functional layer removal method

Abstract

To provide a laminated film which prevents an easily soluble resin layer provided on one film surface of a base material film from easily dissolved in warm water and hot water and is excellent in recyclability.SOLUTION: A laminated film has an easily soluble resin layer on at least one surface of a base material film, wherein the easily soluble resin layer contains a polyester component, the polyester component contains (A) a terephthalic acid and (B) a dicarboxylic acid having a sulfonate group as an acid component, and the total of the content ratio of the component (A) and the component (B) in the total acid component in the easily soluble resin layer is 86.0 mol% or more.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a laminated film and a method for removing a functional layer. [Background technology]

[0002] Traditionally, waste plastic has been disposed of by landfilling, dumping at sea, incineration, etc., but it is becoming difficult to secure landfill sites, and dumping at sea is posing an environmental problem because plastic does not decompose. In addition, while it is possible to use the waste as heat by incineration, this has the problem of emitting carbon dioxide, which contributes to global warming.

[0003] In light of the recent heightened environmental concerns, there is a need for recycling, such as reusing and regenerating waste plastics, and research and development into this area is being actively carried out. Furthermore, most plastics are produced using fossil fuels, and there is a need to develop recycling methods to make effective use of resources.

[0004] Meanwhile, polyester film, which is a type of plastic film, is useful as a base film, and is often used as a laminate film having various functional layers laminated on one or both sides thereof. There are various functional layers, such as a hard coat layer, an adhesive layer, a decorative layer, a light-shielding layer, a polarizing layer, and an ultraviolet-shielding layer, and a laminate film in which a material appropriate for the functional layer is laminated onto a polyester film is used.

[0005] Such laminated films are rarely reused after use, but are instead discarded or incinerated.

[0006] Even if an attempt is made to recycle a laminated film with a functional layer laminated thereon by simply remelting it, the material that constitutes the functional layer will be mixed into the molten polymer, causing an unpleasant odor during extrusion or a decrease in the melt viscosity of the polymer, which can lead to breakage during film production. Even if it were possible to produce a film, deterioration in quality due to discoloration of the resulting film or the inclusion of foreign matter is unavoidable.

[0007] Even if the functional layer is physically removed by scraping it off and then melt extrusion is performed, problems will arise such as the remaining functional layer clogging the filter during the filtration process during extrusion, making it impossible to produce a normal film.

[0008] Methods for recycling laminated films include, for example, the techniques disclosed in Patent Documents 1 and 2. These techniques involve a laminated film in which a readily soluble resin layer and a surface functional layer are laminated in this order on at least one surface of a base film. With this configuration, after use, the base film can be separated and recovered from the laminated film by washing with a solvent that can dissolve only the easily soluble resin layer but not the base film. The separated and recovered material is remelted, making it possible to regenerate the resin composition that constituted the base film. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2004-169005 A [Patent Document 2] JP 2002-265665 A Summary of the Invention [Problem to be solved by the invention]

[0010] In the above Patent Documents 1 and 2, the easily soluble resin layer is dissolved with warm water or hot water to separate and remove the surface functional layer, and only the base film is recovered. However, if there is a process in which heat is applied when providing the functional layer, the easily soluble resin layer on the surface of the film may dissolve in warm or hot water during the laminated film manufacturing process, resulting in problems such as the functional layer peeling off in situations where it does not need to be peeled off.

[0011] Therefore, the present invention has been made in consideration of the above-mentioned situation, and the problem to be solved is to provide a laminated film in which a soluble resin layer provided on one film surface of a base film is not likely to be easily dissolved in warm water or hot water, and which has excellent recyclability. [Means for solving the problem]

[0012] As a result of intensive research, the present inventors have found that the above problem can be solved by adjusting the total content of the (A) component and the (B) component in the total acid components in the soluble resin layer to 86.0 mol % or more, so that the above problem can be solved by making the soluble resin layer contain a polyester component, which contains, as acid components, (A) terephthalic acid and (B) a dicarboxylic acid having a sulfonate group. The present invention has been completed based on these findings and has the following aspects.

[0013] [1] A laminate film having a readily soluble resin layer on at least one surface of a base film, the readily soluble resin layer containing a polyester component, the polyester component containing, as acid components, (A) terephthalic acid and (B) a dicarboxylic acid having a sulfonate group, and the total content of the (A) component and the (B) component in all acid components in the readily soluble resin layer is 86.0 mol % or more. [2] The laminate film according to [1] above, wherein the content of the component (B) in all acid components is 8.0 mol % or less. [3] The laminate film according to the above [1] or [2], wherein the component (B) contains at least sodium 5-sulfoisophthalate. [4] The laminate film according to any one of the above [1] to [3], wherein the base film is a polyester film. [5] The laminate film according to any one of the above [1] to [4], which has a functional layer on the easily soluble resin layer. [6] The laminated film described in [5] above, wherein the functional layer is a silicone release layer. [7] A method for removing a functional layer, comprising: a functional layer removal step of cleaning the laminate film described in [5] or [6] above with a cleaning agent to remove the functional layer together with the easily soluble resin layer from the base film. [8] The method for removing a functional layer described in [7] above, wherein the cleaning agent is an alkaline aqueous solution. Effect of the Invention

[0014] The laminated film of the present invention has excellent recyclability because the easily soluble resin layer provided on one film surface is not likely to dissolve easily in warm water or hot water, and when a functional layer is laminated on the easily soluble resin layer, the functional layer can be easily removed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Next, an example of an embodiment of the present invention will be described, however, the present invention is not limited to the embodiment described below.

[0016] [Laminated film] The laminate film of the present invention (hereinafter also referred to as "the present film") has a readily soluble resin layer on at least one surface of a base film. In addition, the present film preferably has a functional layer formed from various resin materials laminated on the easily soluble resin layer.

[0017] <Base film> The substrate film constituting the present film may have a single layer structure or a multilayer structure. When the present film has a multilayer structure, it may have a two-layer structure, a three-layer structure, or a four-layer structure or more without departing from the gist of the present invention, and the number of layers is not particularly limited. The base film may be a non-stretched film (sheet) or a stretched film. Among them, a uniaxially or biaxially stretched film is preferable, and a biaxially stretched film is more preferable from the viewpoints of balance of mechanical properties, flatness, and thinning.

[0018] Examples of the substrate film include resin films such as polyester films, polycarbonate films, polyimide films, triacetyl cellulose films, polyolefin films, polyacrylate films, polystyrene films, polyvinyl chloride films, polyvinyl alcohol films, and nylon films. Among these, polyester films are particularly preferred.

[0019] The polyester constituting the polyester film is not particularly limited, and any polyester available on the market can be appropriately used. Specifically, polyesters obtained by polycondensation of dicarboxylic acids and diols are exemplified, and the dicarboxylic acids are preferably aromatic dicarboxylic acids, and the diols are preferably aliphatic glycols. The polyester film preferably contains polyester as a main component. When the base film has a multi-layer structure, the main component resin of each layer is preferably polyester. The term "main component resin" refers to the resin that is most abundant among the resins constituting each layer, and is, for example, a resin that accounts for 50% by mass or more, particularly 70% by mass or more, and even more particularly 80% by mass or more (including 100% by mass) of the resins constituting each layer.

[0020] Examples of the aromatic dicarboxylic acid include terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, and phthalic acid. Examples of the aliphatic glycol component include ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, 1,4-cyclohexanedimethanol, and neopentyl glycol.

[0021] The polyester may be a homopolyester or a copolymer polyester. Specific examples of polyesters include polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polybutylene-2,6-naphthalate, and the like, with polyethylene terephthalate being preferred among these.

[0022] The polyester may be a copolymer polyester containing a third component other than the dicarboxylic acid, preferably the aromatic dicarboxylic acid, that constitutes the polyester, and the diol, preferably the aliphatic glycol, that constitutes the polyester, as a copolymer component. For example, the third component is a component other than terephthalic acid and ethylene glycol in the case of polyethylene terephthalate. Specifically, polyethylene terephthalate may have about 30 mol % or less of dicarboxylic acid units other than terephthalic acid out of 100 mol % of dicarboxylic acid units, and may have about 30 mol % or less of diol units other than ethylene glycol out of 100 mol % of diol units.

[0023] The polyester polymerization catalyst is not particularly limited, and any conventionally known compound can be used, such as titanium compounds, germanium compounds, antimony compounds, manganese compounds, aluminum compounds, magnesium compounds, and calcium compounds.

[0024] In order to suppress the amount of precipitation of oligomer components, the polyester film may be produced using a polyester having a low content of oligomer components as a raw material. As a method for producing a polyester having a low content of oligomer components, various known methods can be used, such as a method of performing solid-phase polymerization after the production of a polyester. In addition, the amount of precipitation of oligomer components can be suppressed by configuring the polyester film constituting the base film as three or more layers and making the outermost layer of the polyester film a layer made of a polyester raw material with a low content of oligomer components. The polyester may also be obtained by carrying out esterification or transesterification, followed by melt polycondensation at a higher reaction temperature under reduced pressure.

[0025] The base film may contain particles for the main purpose of imparting easy slippage and preventing scratches during each process. The type of particles is not particularly limited as long as they are particles capable of imparting easy slippage, and specific examples include inorganic particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, and titanium oxide, and organic particles such as acrylic resin, styrene resin, urea resin, phenol resin, epoxy resin, and benzoguanamine resin. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process can also be used as the above particles.

[0026] The shape of the particles to be used is not particularly limited, and any of spherical, block, rod-like, flat, etc. may be used. There is also no particular restriction on the hardness, specific gravity, color, etc. These particles may be used alone or in combination of two or more kinds, if necessary.

[0027] The average particle size of the particles used is usually in the range of 0.05 to 5 μm, preferably 0.1 to 4 μm, and more preferably 0.1 to 3 μm, in consideration of both the transparency and the ease of handling of the film.

[0028] When the base film has a multi-layer structure and contains particles, the particles are preferably contained in at least one of the layers. When the base film has a surface layer and an intermediate layer, the particles are preferably contained in the surface layer. The particles may be contained in one surface layer or both surface layers. By containing particles in the surface layer, the content of particles in the entire base film can be reduced, while effectively imparting lubricity and the like.

[0029] The content of particles in the particle-containing layer is usually 0.01% by mass or more and less than 10% by mass, preferably 0.05 to 5% by mass, and more preferably 0.05 to 3% by mass. When there are no particles or when there are only a few particles, the transparency of the substrate film is high, resulting in a substrate film that is good in terms of transparency. On the other hand, when the particles are contained in the above range, the slipperiness is also good. When the base film has a multilayer structure, the layer containing the particles is preferably a surface layer, but when the base film has a single layer structure, the layer containing the particles is the entire base film.

[0030] The method of adding particles to the base film is not particularly limited, and any conventionally known method can be used. For example, the particles can be added at any stage of producing the resin (e.g., polyester) constituting each layer, but in the case of polyester, it is preferable to add the particles after the completion of the esterification or transesterification reaction.

[0031] In addition to the above-mentioned particles, the base film may contain additives such as conventionally known antioxidants, antistatic agents, ultraviolet absorbers, heat stabilizers, lubricants, dyes, pigments, etc. When the base film has a multilayer structure, each additive may be added to at least one of the multiple layers.

[0032] The thickness of the base film is not particularly limited as long as it is within a range that allows film formation, but is usually in the range of 9 to 100 μm, preferably 12 to 75 μm, more preferably 25 to 75 μm, and further preferably 25 to 50 μm. When the base film has a multilayer structure, the thickness of the base film as a whole is within the above range.

[0033] <Easily soluble resin layer> The readily soluble resin layer of the present film (hereinafter also referred to as "the readily soluble resin layer") is provided on at least one surface of the base film, and when the present film has a functional layer, it is preferable to provide the readily soluble resin layer between the base film and the functional layer. With this configuration, by washing the laminate film after use with a cleaning agent, it is possible to completely separate and remove the readily soluble resin in the cleaning agent and the functional layer and the residues and impurities attached to the functional layer. In other words, the base film can be separated and recovered from the laminate film. In addition, the separated and recovered base film can be remelted, making it possible to regenerate the resin that constitutes the base film.

[0034] The readily soluble resin layer includes a polyester component, and the polyester component includes, as a dicarboxylic acid, i.e., an acid component, (A) terephthalic acid (hereinafter also referred to as "component (A)") and (B) a dicarboxylic acid having a sulfonate group (hereinafter also referred to as "component (B)"). The polyester component may further include (C) another dicarboxylic acid (hereinafter also referred to as "component (C)") in addition to the components (A) and (B). The term "polyester component" refers to a polyester constituent obtained by polycondensation of at least one dicarboxylic acid component and at least one diol component.

[0035] The components (A) to (C) in the polyester component may be derived from a single polyester constituting the present easily soluble resin layer, or may be derived from different polyesters. The readily soluble resin layer may be formed, for example, from a copolymer polyester containing the components (A) and (B) or from a copolymer polyester containing the components (A), (B) and (C). Furthermore, the readily soluble resin layer may be formed using, for example, a copolymer polyester containing at least two of the components (A), (B), and (C), specifically, a copolymer polyester containing the components (A) and (C) or a copolymer polyester containing the components (B) and (C).

[0036] Furthermore, a combination of a plurality of polyesters each having one kind of dicarboxylic acid component, such as a homopolyester, may be used so that the readily soluble resin layer contains the above-mentioned components (A) and (B). In addition to the copolymer polyester, a polyester consisting of one kind of dicarboxylic acid component, such as a homopolyester, may be used in combination. In any case, the readily soluble resin layer should ultimately contain the component (A) and the component (B). Moreover, the components (A) to (C) may all be derived from different polyesters (regardless of whether they are homopolyesters or copolymer polyesters).

[0037] As described above, the present easily soluble resin layer contains a polyester component, and the polyester component contains the (A) component and the (B) component as acid components, but these do not necessarily have to be contained as copolymerized polyesters, and may be a blend of polyesters containing each component. The component (B) is preferably contained as one of the acid components of the copolymer polyester. In addition, in the polyester consisting of one kind of dicarboxylic acid component, such as homopolyester, the dicarboxylic acid component is preferably a terephthalic acid component, and the homopolyester is preferably polyethylene terephthalate (PET).

[0038] The readily soluble resin layer contains a polyester component, and the polyester component contains the dicarboxylic acid having a sulfonate group (B) as an acid component, i.e., the component (B), thereby improving the solubility in a cleaning agent described later. Examples of the (B) component include alkali metal salts, alkaline earth metal salts, and ammonium salts of sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, and 4-sulfonaphthalene-2,7-dicarboxylic acid. Among them, from the viewpoint of solubility in a cleaning agent, it is preferable to contain at least 5-sodium sulfoisophthalate. These (B) components may be used alone or in combination of two or more kinds. In the present invention, the component (A) is terephthalic acid, which is the acid component contained in the polyester component, excluding the component (B).

[0039] The component (C) may be any dicarboxylic acid other than the components (A) and (B), and examples thereof include isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, and sebacic acid. These components (C) may be used alone or in combination of two or more.

[0040] In the present easily soluble resin layer, the total content of the (A) component and the (B) component in the total acid components in the present easily soluble resin layer is 86.0 mol % or more. If the total content is less than 86.0 mol %, the present easily soluble resin layer has a low glass transition temperature and is easily dissolved in warm water or hot water, causing defects in the laminate film. From this viewpoint, the total content of the (A) component and the (B) component is preferably 90.0 mol% or more, more preferably 94.0 mol% or more, and even more preferably 98.0 mol% or more. The upper limit is 100 mol%, that is, the acid components in the readily soluble resin layer are only the (A) component and the (B) component. If the total content of the (A) component and the (B) component in the total acid components in the readily soluble resin layer is within the above range, the readily soluble resin layer becomes a resin composition with a high glass transition temperature and becomes a coating that is resistant to heat and water, and as a result, the readily soluble resin layer is not likely to be easily dissolved in warm water or hot water. The term "total acid components" means all of the polyesters constituting the readily soluble resin layer, that is, dicarboxylic acid components in the polyester components.

[0041] In the present easily soluble resin layer, the content ratio of the (A) component in the total acid components is preferably 80.0 mol% or more, more preferably 85.0 mol% or more, even more preferably 90.0 mol% or more, and particularly preferably 93.0 mol% or more. If the content ratio of the (A) component is within this range, the present easily soluble resin layer becomes a resin composition with a high glass transition temperature, and there is no risk that the present easily soluble resin layer will easily dissolve in warm water or hot water. The upper limit is not particularly limited as long as it is less than 100 mol%, but is preferably 99.0 mol% or less, more preferably 98.0 mol% or less, and even more preferably 97.0 mol% or less.

[0042] In the present easily soluble resin layer, the content of the (B) component in the total acid components is preferably 8.0 mol % or less, more preferably 7.5 mol % or less, even more preferably 7.0 mol % or less, and particularly preferably 6.6 mol % or less. Furthermore, there is no particular lower limit to the content of the (B) component as long as it exceeds 0%, but it is preferably 1.0 mol % or more, more preferably 2.0 mol % or more, and even more preferably 3.0 mol % or more. When the content of the component (B) in the total acid components is equal to or higher than the lower limit, the solubility in the detergent is good, whereas when the content is equal to or lower than the upper limit, the blocking resistance is good.

[0043] When the easily soluble resin layer contains the above-mentioned (C) other dicarboxylic acid, i.e., the (C) component, the content ratio of the (C) component in the total acid components is preferably 14.0 mol % or less, more preferably 10.0 mol % or less, further preferably 6.0 mol % or less, and particularly preferably 2.0 mol % or less. The lower limit is 0 mol %. When the content of the component (C) is within this range, the readily soluble resin layer has a resin composition with a high glass transition temperature, and there is no risk of the readily soluble resin layer being easily dissolved in warm water or hot water.

[0044] The diol component in the polyester component is not particularly limited, and examples thereof include ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, etc. The diol components may be used alone or in combination of two or more. In the present easily soluble resin layer, it is preferable that the diol component in the polyester component contains ethylene glycol, which maintains crystallinity and improves the basic properties of the film, such as heat resistance and strength. The content of ethylene glycol is preferably in the range of 40 to 100 mol %, more preferably in the range of 60 to 100 mol %, further preferably in the range of 80 to 100 mol %, and particularly preferably in the range of 80 to 96 mol % of the total diol components. In addition, when polyester is produced (polycondensed) using ethylene glycol as one of the raw materials, diethylene glycol is usually produced as a by-product from ethylene glycol. In this specification, this diethylene glycol is referred to as by-product diethylene glycol. The amount of diethylene glycol produced as a by-product from ethylene glycol varies depending on the type of polycondensation, etc., but is about 5 mol % or less of the ethylene glycol. In the present invention, the by-product diethylene glycol of 5 mol % or less is also included in ethylene glycol. On the other hand, depending on the content of diethylene glycol, more specifically, when diethylene glycol is contained in excess of 5 mol %, diethylene glycol is distinguished from ethylene glycol.

[0045] The easily soluble resin layer only needs to contain the above-mentioned polyester component, and may contain other resin components in addition to the polyester component.

[0046] The thickness of the easily soluble resin layer in the present film is preferably from 0.01 to 10 μm, more preferably from 0.05 to 6 μm, and even more preferably from 0.5 to 5 μm, from the viewpoint of improving solubility in a cleaning agent. The thickness of the present film is preferably from 9 to 110 μm, more preferably from 12 to 85 μm, further preferably from 25 to 85 μm, and particularly preferably from 25 to 60 μm.

[0047] The easily soluble resin layer may also contain particles from the viewpoint of imparting easy slippage and preventing the occurrence of scratches in each process. As the particles, the same particles as those contained in the base film can be used, and the particle size, content, etc. are also the same.

[0048] As an example of a method for producing the easily soluble resin layer, a commonly known film production method can be adopted. For example, when the main component resin of each layer constituting the present film is polyester and the surface layer of the multi-layer structure is produced as an easily soluble resin layer, the film can be produced as follows. However, the following explanation is an example of a method for producing a laminated film, and the present film is not limited to a laminated film produced by such a production method. In addition, when the present film consists of three layers of three types, namely Layer A / Layer B / Layer C, and Layer A is a readily soluble resin layer, Layer B / Layer C serves as a base film, and the present film can be said to be a laminate film having a readily soluble resin layer on one surface of the base film.

[0049] For example, when producing a biaxially stretched film, a method is preferred in which the above-mentioned raw material polyester is extruded as a molten sheet from a die using multiple extruders, and then cooled and solidified on a rotating cooling drum (casting drum) to obtain an unstretched laminate sheet. In this case, it is preferred to increase the adhesion between the laminate sheet and the rotating cooling drum in order to improve the flatness of the laminate sheet, and an electrostatic application adhesion method and / or a liquid application adhesion method are preferably used. In this way, an unstretched laminate sheet is obtained. The polyester raw material may be fed to the extruder in the form of pellets or the like after being appropriately dried. Particles, an ultraviolet absorbing agent, and other additives may be appropriately mixed into the pellets.

[0050] Next, the unstretched laminate sheet obtained by the above method is stretched in one direction by a roll or tenter type stretching machine. The stretching temperature is usually 70 to 120° C., preferably 80 to 110° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3 to 6 times. Next, the film is stretched in a direction perpendicular to the first-stage stretching direction. In this case, the stretching temperature is usually 70 to 170° C., preferably 80 to 120° C., and the stretch ratio is usually 3 to 7 times, preferably 3.5 to 6 times.

[0051] Subsequently, the film is heat-treated under tension or relaxation of 30% or less at a temperature of 180 to 270°C to obtain a biaxially stretched film. In the above stretching, a method of stretching in one direction in two or more stages can be adopted. In that case, it is preferable to perform the stretching so that the final stretch ratios in both directions are each within the above range.

[0052] A simultaneous biaxial stretching method can also be used to produce the laminated film. The simultaneous biaxial stretching method is a method in which the unstretched sheet is simultaneously stretched and oriented in the longitudinal and transverse directions under a temperature controlled condition usually at 70 to 120° C., preferably 80 to 110° C. The stretching ratio is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times in terms of area ratio. Subsequently, the film is heat-treated under tension or relaxation of 30% or less at a temperature of 170 to 250° C. to obtain a stretched and oriented film. Regarding the simultaneous biaxial stretching device employing the above-mentioned stretching method, a conventionally known stretching method such as a screw method, a pantograph method, or a linear drive method can be employed.

[0053] The longitudinal direction of the film refers to the direction in which the film advances during the film production process, i.e., the winding direction of the film roll. The width direction refers to the direction parallel to the film surface and perpendicular to the longitudinal direction, i.e., the direction parallel to the central axis of the roll when the film is in a roll shape.

[0054] The easily soluble resin layer may be provided by in-line coating, which treats the film surface during the polyester film production process, or by off-line coating, which applies the resin outside the system onto a film that has already been produced.

[0055] <Functional layer> The laminated film of the present invention may have a functional layer. The components of the functional layer are not particularly limited, but from the viewpoint of removal by the functional layer removal method of the present invention, it is preferable that the functional layer is composed of a resin. Examples of the functional layer include a hard coat layer, a tacky adhesive layer, a release layer, a decorative layer, a light-shielding layer, an ultraviolet shielding layer, an easy-adhesion layer (primer layer), an antistatic layer, a refractive index adjustment layer, and an oligomer sealing layer.

[0056] The hard coat layer is a layer provided to impart scratch resistance to the base film, etc. Materials for forming the hard coat layer are not particularly limited, but examples thereof include monofunctional (meth)acrylates, polyfunctional (meth)acrylates, and cured products of reactive silicon compounds such as tetraethoxysilane.

[0057] The adhesive layer is a layer provided for adhesively adhering the present film to other devices, etc. The material constituting the adhesive layer is not particularly limited, but for example, known adhesive resins such as acrylic, rubber, and silicone adhesive resins can be used.

[0058] The release layer is a layer provided to impart releasability to a base film, and is, for example, a layer provided on a release film used in forming green sheets used in the manufacture of ceramic electronic components, or in adhesive separators for optical components used in the manufacture of flat panel displays such as polarizing plates and optical filters. The material constituting the release layer is not particularly limited, and examples thereof include those containing a curable silicone resin as a main component, modified silicone resins obtained by graft polymerization with urethane resins, epoxy resins, etc., compounds containing long-chain alkyl groups, fluorine compounds, hydrocarbon waxes, etc. Among these, silicone release layers are preferred.

[0059] The decorative layer is a layer provided to impart design. The material constituting the decorative layer is not particularly limited, but examples thereof include polyurethane resin, vinyl resin, polyamide resin, polyester resin, acrylic resin, polyvinyl acetal resin, etc. Pigments, dyes, etc. are added to these resins to provide decoration.

[0060] The light-shielding layer or ultraviolet-shielding layer is a layer provided to protect the contents from ultraviolet light, visible light, etc. Materials constituting the light-shielding layer or ultraviolet-shielding layer are not particularly limited, and examples thereof include various resins described in the decorative layer, inorganic fillers such as calcium carbonate, talc, clay, kaolin, silica, diatomaceous earth, and barium sulfate, and organic fillers such as wood flour, pulp powder, and cellulose powder.

[0061] The easy-adhesion layer (primer layer) is a layer provided for adhering other layers or films onto the base film, and may include, but is not limited to, polyurethane resins, vinyl resins, polyamide resins, polyester resins, acrylic resins, polyvinyl acetal resins, and the like, as well as various crosslinking agents and particles.

[0062] The antistatic layer is a layer provided to prevent static electricity caused by contact with or peeling off from other materials. The antistatic agent used in the antistatic layer is not particularly limited, but includes nonionic, cationic, anionic, and amphoteric surfactants, conductive polymers such as polypyrrole, polyaniline, poly(3,4-ethylenedioxythiophene), poly(4-styrenesulfonate), and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), metal oxide fillers such as SnO2 (Sb doped), In2O3 (Sn doped), and ZnO (Al doped), and carbon compounds such as graphene, carbon black, and carbon nanotubes (CNT). These may be used alone or in combination of two or more. The antistatic layer may be formed from a resin composition containing an antistatic agent. Examples of resins contained in the resin composition include polyester resins, acrylic resins, and urethane resins.

[0063] The refractive index adjusting layer is a layer provided to adjust the refractive index. The material constituting the refractive index adjusting layer is not particularly limited, but may be polyester resin, acrylic resin, urethane resin, polycarbonate resin, epoxy resin, alkyd resin, urea resin, fluororesin, metal oxide such as zirconium oxide or titanium oxide, etc. These may be used alone or in combination of two or more.

[0064] The oligomer sealing layer is a layer provided to prevent film whitening and foreign matter after a heating process. The material constituting the oligomer sealing layer is not particularly limited, but examples thereof include amine compounds, ionic resins, and highly crosslinked coating films.

[0065] These functional layers may be a single layer, or two or more types of layers may be laminated. When two or more kinds of layers are laminated, it is preferable that at least one layer is made of a resin.

[0066] When the laminated film of the present invention includes the functional layer, the functional layer is preferably laminated on a soluble resin layer provided on at least one surface of the base film. By interposing the soluble resin layer between the base film and the functional layer, the soluble resin can be dissolved in the cleaning agent by cleaning with a cleaning agent described later, and the functional layer can be completely removed together with the soluble resin layer, so that only the base film can be recovered.

[0067] [Functional layer removal method] As described above, since the present film has a readily soluble resin layer, when the present film has a functional layer, the functional layer formed on the readily soluble resin layer can be easily peeled off and removed. An example of a method for removing the functional layer (hereinafter also referred to as "the functional layer removal method") is a method including a functional layer removal step of washing the film with a cleaning agent to dissolve the readily soluble resin layer, and removing the functional layer together with the readily soluble resin layer from the base film.

[0068] <Cleaning agent> The cleaning agent is preferably an aqueous alkaline solution so that the base film can be recovered without being dissolved.

[0069] Examples of the alkaline aqueous solution include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide and barium hydroxide; alkali metal carbonates such as sodium carbonate and potassium carbonate; alkali metal phosphates such as trisodium phosphate, sodium pyrophosphate, sodium tripolyphosphate, sodium tetrapolyphosphate, tripotassium phosphate, potassium pyrophosphate, and potassium tripolyphosphate; alkali metal silicates such as sodium orthosilicate, sodium metasilicate, and potassium silicate; and ammonia.

[0070] Among the above alkaline aqueous solutions, alkali metal hydroxides are preferred, and from the viewpoints of availability and cleaning properties, sodium hydroxide and potassium hydroxide are more preferred. As the aqueous alkaline solution in the present cleaning agent, one type may be used alone, or two or more types may be used in combination.

[0071] The alkaline (earth) metal content in the entire cleaning agent is preferably 1 to 35 mass%, more preferably 1 to 30 mass%, and even more preferably 1 to 25 mass%. If it is within the above range, sufficient effect as a cleaning agent can be obtained.

[0072] The aqueous alkaline solution may further contain a compound having at least one hydroxyl group for the purpose of enhancing the cleaning effect. Examples of the compound having at least one hydroxyl group include alcohols and phenols.

[0073] Examples of the alcohols include monohydric alcohols such as hexafluoro-2-propanol, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, benzyl alcohol, ethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; dihydric alcohols such as ethylene glycol, diethylene glycol, and propylene glycol; and polyhydric alcohols such as glycerin.

[0074] Examples of phenols include phenol, xylenol, salicylic acid, picric acid, naphthol, catechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, dibutylhydroxytoluene, bisphenol A, cresol, estradiol, eugenol, gallic acid, guaiacol, phenolphthalein, serotonin, dopamine, adrenaline, noradrenaline, thymol, tyrosine, and hexahydroxybenzene.

[0075] As the compound having at least one hydroxyl group, these alcohols and / or phenols may be used alone or in combination of two or more kinds.

[0076] In addition to the above-mentioned components, various additives can be added to the alkaline aqueous solution, such as surfactants, antioxidants, rust inhibitors, pH adjusters, preservatives, viscosity adjusters, thickeners, and defoamers.

[0077] <Functional layer removal process> Examples of the cleaning method for the present film in the functional layer removal step include an immersion method in which the film is immersed in a cleaning tank containing a cleaning agent, a coating method in which a cleaning agent in a solution state is applied, a spraying method in which a cleaning agent in a solution state or a vaporized cleaning agent is sprayed, etc. Among these, the immersion method is preferred from the viewpoint of the penetration of the cleaning agent.

[0078] The temperature of the cleaner in the immersion method is preferably room temperature (20°C) or higher. At room temperature (20°C) or higher, the viscosity of the cleaner is low and the cleaner easily penetrates into the easily soluble resin layer, resulting in good cleaning properties. From the above viewpoints, the temperature of the cleaner in the immersion method is more preferably 40°C or higher, further preferably 50°C or higher, and particularly preferably 60°C or higher. The upper limit of the temperature of the cleaning agent is preferably a temperature equal to or lower than the boiling point when the cleaning agent is used in a solution state, and is preferably 100° C. or lower, more preferably 90° C. or lower, in the case of an alkaline aqueous solution, which is a suitable embodiment of the cleaning agent according to the present invention. In addition, even in the case of a method other than the immersion method, the temperature of the cleaning agent during cleaning is the same as above.

[0079] It is preferable to adjust the immersion time as follows depending on the type of object to be cleaned.

[0080] When a laminated film having an acrylic adhesive layer as a functional layer is to be cleaned, the cleaning time is preferably 1 second or more and 30 minutes or less. When the time is 1 second or more, the cleaning agent sufficiently penetrates into the easily soluble resin layer, and cleaning properties can be exhibited. On the other hand, when the time is 30 minutes or less, the base film does not dissolve excessively. From the above viewpoints, it is more preferable that the time is 15 seconds or more and 30 minutes or less, further more preferable that the time is 30 seconds or more and 25 minutes or less, and particularly preferable that the time is 1 minute or more and 20 minutes or less.

[0081] When a laminate film having an acrylic hard coat layer as a functional layer is to be cleaned, the cleaning time is preferably 1 second or more and 30 minutes or less. When the time is 1 second or more, the cleaning agent sufficiently penetrates into the easily soluble resin layer, and cleaning properties can be exhibited. On the other hand, when the time is 30 minutes or less, the base film does not dissolve excessively. From the above viewpoints, it is more preferable that the time is 15 seconds or more and 30 minutes or less, further more preferable that the time is 30 seconds or more and 25 minutes or less, and particularly preferable that the time is 1 minute or more and 20 minutes or less.

[0082] When the object to be cleaned is a laminated film having a silicone release layer as a functional layer, the cleaning time is preferably 1 second or more and 30 minutes or less. When the time is 1 second or more, the cleaning agent sufficiently penetrates into the easily soluble resin layer, and cleaning properties can be exhibited. On the other hand, when the time is 30 minutes or less, the base film does not dissolve excessively. From the above viewpoints, it is more preferable that the time is 15 seconds or more and 30 minutes or less, further more preferable that the time is 30 seconds or more and 25 minutes or less, and particularly preferable that the time is 1 minute or more and 20 minutes or less.

[0083] Specific aspects of the functional layer removal step in the present functional layer removal method are as follows, depending on the shape of the laminated film that is the waste material.

[0084] When the waste laminated film is in the form of a roll, it is preferable to provide a winding device in front of the cleaning tank containing the above-mentioned cleaning agent, and to wind the laminated film from the device and introduce it into the cleaning tank for cleaning. Then, it is preferable to continuously move to the next recovery step. In addition, in the functional layer removal step, equipment equipped with physical means such as a roll brush, ultrasonic waves, micro / nano bubbles, water flow, or compressed cold air may be provided for the purpose of efficiently removing the functional layer from the laminated film.

[0085] When the waste laminated film is in a lump form, it is preferable to install a cutting device before the washing step, cut it into flakes, and introduce it into a washing tank containing the above-mentioned cleaning agent. By cutting it into flakes, the contact area between the laminated film and the cleaning agent becomes larger, making it easier for the cleaning agent to penetrate into the easily soluble resin layer, and the functional layer can be removed efficiently. In this embodiment, a method of continuously introducing the flaky laminated film into the washing tank using a belt conveyor or the like is preferable. By adopting such an embodiment, washing can be performed with high productivity. In this embodiment, washing can also be performed in a batch manner.

[0086] <Recovery process> The functional layer removal method may include a recovery step of recovering the base film after the functional layer removal step. Also, the recovery step may include a rinsing step and a drying step before the recovery step. As the recovery method, an appropriate method can be selected depending on the shape of the laminated film that is the waste material. When the waste laminated film is in the form of a roll, it can be efficiently recovered by continuously carrying out the processes of functional layer removal, rinsing, and drying in a roll-to-roll manner and winding it up. Furthermore, in the case where the waste laminated film is in a lump form, as described above, a cutting process is carried out before the functional layer removal process, and the laminated film cut into flakes is continuously passed through a functional layer removal process, a rinsing process, and a drying process using a belt conveyor or the like to recover the flaky substrate, such as polyester. The base film recovered as described above is advantageously pelletized after recovery in terms of handling.

[0087] <Rinse process> As described above, the present functional layer removal method may include a rinsing step for washing away the cleaning agent between the functional layer removal step and the recovery step. This is a step for washing away the cleaning agent adhering to the substrate film from which the easily soluble resin layer and the functional layer have been removed with a rinsing liquid. Water is preferable as the rinsing liquid, but if rinsing is not necessary, the rinsing step can be omitted.

[0088] <Drying process> The above rinsing step may be followed by a drying step. The conditions for the drying step are not particularly limited, and may usually be 70 to 150° C. and about 1 to 30 minutes. As a drying method, a general method such as heating and drying using an infrared heater or oven, hot air drying using a hot air dryer, or microwave heating and drying can be used.

[0089] <<Explanation of terms>> In the present invention, the term "film" includes the term "sheet", and the term "sheet" includes the term "film". In the present invention, when it is described as "X to Y" (X and Y are any numbers), unless otherwise specified, it includes the meaning of "X or more and Y or less", as well as the meaning of "preferably larger than X" or "preferably smaller than Y". In addition, when it is stated that the amount is "X or more" (X is any number), it also means that the amount is "preferably greater than X" unless otherwise specified, and when it is stated that the amount is "Y or less" (Y is any number), it also means that the amount is "preferably smaller than Y" unless otherwise specified. EXAMPLES

[0090] 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 without departing from the gist of the present invention.

[0091] <Evaluation method> (1) Measurement of intrinsic viscosity (dl / g) of polyester 1 g of polyester from which other polymer components incompatible with polyester and pigments had been removed was precisely weighed, dissolved in 100 ml of a mixed solvent of phenol / tetrachloroethane = 50 / 50 (mass ratio), and measured at 30°C.

[0092] (2) Measurement of average particle size The particle size at an integrated volume fraction of 50% in the equivalent spherical distribution (d50), measured using a centrifugal sedimentation type particle size distribution analyzer (SA-CP3 type) manufactured by Shimadzu Corporation, was taken as the average particle size.

[0093] (3) Solubility evaluation Among the laminated films obtained in each of the Examples and Comparative Examples, the laminated films (3 cm x 4 cm) before the functional layer was provided were immersed in 30 mL of water or an alkaline aqueous solution. The surface of the laminated film after immersion was subjected to a qualitative analysis of Na element using an X-ray fluorescence analyzer (XRF, Shimadzu Corporation's "EDX-8000"), and the solubility of the easily soluble resin layer was evaluated according to the following criteria. When water was used, the laminated film was immersed at 90° C. for 20 minutes, and when an alkaline aqueous solution (2% by mass NaOH) was used, the laminated film was immersed at 90° C. for 20 minutes. 〇(good): No Na element detected (dissolves) × (poor): Na element is detected (not dissolved)

[0094] (4) Evaluation of blocking resistance Of the laminate films obtained in each Example and Comparative Example, two laminate films before the functional layer was provided were prepared, and the easily soluble resin layer (Layer A described later) and the base film layer (Layer C described later) on the opposite side to Layer A were overlapped, and a test piece of 12 cm x 10 cm was cut out and subjected to heating at 40°C, 80% RH, and 10 kg / cm 2 The films were then pressed together for 20 hours at 100° C. for 20 hours. After that, the films were peeled from each other using AUTOGRAPH manufactured by Shimadzu Corporation in accordance with the method specified in ASTM D1893, and the peel load was measured. The lighter the peel load, the less likely blocking occurs and the better the result, that is, the more anti-blocking the film is. The evaluation criteria were as follows: 〇(good): 35g / cm or less △(fair): Over 35g / cm, under 100g / cm × (poor): 100 g / cm or more, the film breaks during the evaluation, or obvious blocking occurs due to pressing

[0095] (5) Functional layer removal evaluation (Laminated film with silicone release layer) In the examples and comparative examples, the laminated films after the silicone release layer was provided were evaluated as follows. A laminated film (3cm x 4cm) with a silicone release layer was cleaned using a cleaning agent, and the surface of the cleaned laminated film was quantitatively analyzed for Si element using an X-ray fluorescence analyzer (XRF, Shimadzu Corporation's EDX-8000). In this evaluation, the amount of Si element on the laminated film surface before cleaning was set to 100%, and the amount of Si element on a plain laminated film without a functional layer coating was set to 0%, to calculate the removal rate of the functional layer, and evaluated according to the following criteria. The functional layer was removed by immersing the laminated film in a cleaning tank containing 30 mL of cleaning agent. When water was used as the cleaning agent, the laminated film with the functional layer was cleaned at 90°C for 20 minutes, and when an alkaline aqueous solution (2% by mass NaOH) was used as the cleaning agent, the laminated film with the functional layer was cleaned at 90°C for 20 minutes. 〇(good): Removal rate 90~100% ×(poor): Removal rate 0~90%

[0096] (6) Measurement of glass transition temperature (Tg) The glass transition temperature (Tg) of each of the polyester raw materials used in the examples and comparative examples was measured as follows. The glass transition temperature (Tg) of the polyester raw material was measured in accordance with JIS K-7121:2012. Specifically, using a PerkinElmer DSC8500, 5 mg of the sample was heated from 25°C to 300°C at a heating rate of 10°C / min, and then rapidly cooled to 25°C at a cooling rate of 600°C / min. The same sample was again heated from 25°C to 300°C at a heating rate of 10°C / min, and rapidly cooled to 25°C at a cooling rate of 600°C / min, and the glass transition temperature (Tg) was obtained from the DSC curve.

[0097] <Materials used> [Polyester raw materials] The raw material compositions of the polyesters used in the examples and comparative examples are shown in Table 1. In Table 1, TPA stands for terephthalic acid, IPA stands for isophthalic acid, 5-SIPA-Na stands for sodium 5-sulfoisophthalate, EG stands for ethylene glycol, and DEG stands for diethylene glycol. Polyester E was blended with 2% by mass of calcium carbonate having an average particle size of 0.7 μm. The intrinsic viscosities of polyesters D and E were 0.64 dl / g and 0.61 dl / g, respectively. The glass transition temperature of polyester E was not measured.

[0098] [Table 1]

[0099] Example 1 The ingredients for each layer were mixed as shown in Table 2. The mixed raw materials for layers A, B, and C were each co-extruded at 280°C using a separate melt extruder, and then cooled and solidified on a casting drum cooled to 25°C using an electrostatic adhesion method to obtain an unstretched laminated film with three types and three layers (layer A / layer B / layer C). Next, the obtained unstretched laminated film was stretched 3.5 times in the longitudinal direction at 88°C using a roll stretching machine. Furthermore, after preheating at 100°C in a tenter, it was stretched 4.4 times in the transverse direction at 110°C. After biaxial stretching, it was heat-treated at 220°C to obtain a laminated film with a thickness of 31 μm (A layer: 1.55 μm, B layer: 27.9 μm, C layer: 1.55 μm). As shown in Table 2, the easily soluble resin layer corresponds to A layer. Furthermore, a silicone release agent was applied to layer A of the obtained laminated film in an amount of 0.1 g / m2 after drying, the silicone release agent being a mixture of 1.6% by mass of a curable silicone resin (15% diluted KS-847H manufactured by Shin-Etsu Chemical Co., Ltd.), 0.001% by mass of an addition type platinum catalyst (PL-50T manufactured by Shin-Etsu Chemical Co., Ltd.), 19.7% by mass of methyl ethyl ketone, 39.4% by mass of toluene, and 39.3% by mass of heptane. 2 The coating was then heated in an oven at 150° C. for 30 seconds to obtain a laminated film having a silicone release layer. The properties of the obtained laminated film and the laminated film having a silicone release layer were evaluated by the above-mentioned methods. The evaluation results are shown in Table 3.

[0100] Example 2 The same procedure as in Example 1 was carried out except that the composition and thickness conditions were as shown in Table 2 below. The evaluation results are shown in Table 3.

[0101] (Comparative Examples 1 to 3) The same procedure as in Example 1 was carried out except that the composition and thickness conditions were as shown in Table 2 below. The evaluation results are shown in Table 3.

[0102] [Table 2]

[0103] [Table 3]

[0104] As shown in Examples 1 and 2, the laminated film of the present invention did not easily dissolve in warm water or hot water. Therefore, even if a heat application process is included in providing the functional layer, there is no risk of the easily soluble resin layer on the surface of the film dissolving in warm water or hot water, and there is no problem such as the functional layer peeling off when it does not need to be peeled off. In addition, in the laminate films of Examples 1 and 2, when a functional layer was laminated on a readily soluble resin layer, the functional layer could be easily removed using an alkaline aqueous solution. This shows that the laminate film of the present invention has excellent recyclability, allowing the substrate film to be easily recovered. Furthermore, the laminated film of the present invention is also excellent in blocking resistance.

[0105] On the other hand, as shown in Comparative Examples 1 and 2, when the total content of the (A) component and the (B) component in the total acid components in the easily soluble resin layer was less than 86.0 mol%, the solubility in water such as warm water or hot water increased. In Comparative Example 3, the acid component of the easily soluble resin layer was the component (A) alone. In this case, the laminated film was not soluble in warm water or hot water, nor in an alkaline aqueous solution, making it impossible to recycle. In addition, when a functional layer was laminated on the easily soluble resin layer, the functional layer could not be removed using either an alkaline aqueous solution or water. [Industrial Applicability]

[0106] According to the laminated film of the present invention, the easily soluble resin layer provided on one side of the base film is not likely to dissolve easily in warm water or hot water, and therefore there is no problem in that the functional layer laminated on the easily soluble resin layer peels off when peeling is not required, and the film can be used as various functional films according to the type of functional layer. On the other hand, after use, the functional layer can be separated and removed together with the soluble resin layer by washing with an alkaline aqueous solution as a cleaning agent to dissolve the soluble resin layer, and the base film can be recovered. Therefore, when the laminate film of the present invention has a functional layer, when the laminate film having the functional layer is used as a conventional functional film, there is no problem such as peeling of the functional layer, and the base film can be recovered and recycled, making it an extremely useful film that combines functionality and environmental performance.

Claims

1. A substrate film has a soluble resin layer on at least one surface thereof, the easily soluble resin layer contains a polyester component, The polyester component contains, as acid components, (A) terephthalic acid and (B) a dicarboxylic acid having a sulfonate group, and the total content of the (A) component and the (B) component in the total acid components in the easily soluble resin layer is 86.0 mol % or more. The laminate film, wherein the easily soluble resin layer does not dissolve after the laminate film is immersed in water at 90° C. for 20 minutes.

2. A substrate film having a readily soluble resin layer on at least one surface thereof, the easily soluble resin layer contains a polyester component, the polyester component contains, as acid components, (A) terephthalic acid and (B) a dicarboxylic acid having a sulfonate group, and the total content of the (A) component and the (B) component in the total acid components in the easily soluble resin layer is 86.0 mol % or more; A laminated film having a functional layer on the easily soluble resin layer (however, the functional layer does not include an ink receiving layer containing a water-soluble resin or a water-dispersible resin).

3. A substrate film having a readily soluble resin layer on at least one surface thereof, the easily soluble resin layer contains a polyester component, a polyester component comprising, as acid components, (A) terephthalic acid and (B) a dicarboxylic acid having a sulfonate group, a total content ratio of the (A) component and the (B) component in all acid components in the easily soluble resin layer being 86.0 mol % or more, and a content ratio of the (A) component in all acid components in the easily soluble resin layer being 93.0 mol % or more.

4. 3. The laminate film according to claim 1, wherein the content of the component (B) in all acid components is 8.0 mol % or less.

5. The laminate film according to any one of claims 1 to 4, wherein the component (B) contains at least 5-sodium sulfoisophthalate.

6. The laminate film according to any one of claims 1 to 5, wherein the base film is a polyester film.

7. A laminate film described in any one of claims 2 to 6, wherein the easily soluble resin layer does not dissolve after the laminate film is immersed in water at 90°C for 20 minutes.

8. The laminate film according to any one of claims 1 and 3 to 7, further comprising a functional layer on the easily soluble resin layer.

9. The laminate film according to claim 2 or 8, wherein the functional layer is a silicone release layer.

10. A functional layer removing method, comprising: a functional layer removing step of cleaning the laminate film according to claim 8 or 9 with a cleaning agent to remove the functional layer together with the easily soluble resin layer from the base film.

11. A substrate film having a readily soluble resin layer on at least one surface thereof, the easily soluble resin layer contains a polyester component, the polyester component contains, as acid components, (A) terephthalic acid and (B) a dicarboxylic acid having a sulfonate group, and the total content of the (A) component and the (B) component in the total acid components in the easily soluble resin layer is 86.0 mol % or more; A functional layer removing method comprising: a functional layer removing step of cleaning a laminate film having a functional layer on the easily soluble resin layer with a cleaning agent to remove the functional layer from the base film.

12. The method for removing a functional layer according to claim 10 or 11, wherein the cleaning agent is an alkaline aqueous solution.

13. A substrate film having a soluble resin layer on at least one surface thereof, the easily soluble resin layer contains a polyester component, the polyester component contains, as acid components, (A) terephthalic acid and (B) a dicarboxylic acid having a sulfonate group, and the total content of the (A) component and the (B) component in the total acid components in the easily soluble resin layer is 86.0 mol % or more; A method for recycling a laminate film, comprising removing a functional layer from a base film of a laminate film having a functional layer on an easily soluble resin layer, and recovering the base film.

14. A method for recycling a laminated film as described in claim 13, wherein the functional layer is removed using a cleaning agent.

Images