JP2004169005A - Method for recycling laminated film and recycled product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for recycling a laminated film, capable of conducting reuse of the laminate film by a method known as remelting and scarcely causing environmental loading. <P>SOLUTION: In this method for recycling the laminated film, the laminated film in which an easily-soluble resin layer and a surface functional layer are laminated on at least one side of a base film in this order is reclaimed, after it is used, by washing the film with a solvent which dissolves a resin composing the easily-soluble resin layer but does not dissolve another resin composing the base film, so as to separate and recover the base film or its pulverized material from the laminated film, and then remelting the separated and recovered material, so as to reclaim a resin composition which has composed the base film. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to a method for recycling a laminated film.

  BACKGROUND ART Conventionally, a laminated film in which a surface functional layer is laminated on at least one side of a base film has been used in various industrial products and manufacturing processes of industrial products.

  For example, a release film for a process in which a release layer such as a curable silicone resin film is formed on the surface of a polyester film can be used as a film for a process of manufacturing electronic components such as a ceramic capacitor, a ceramic substrate, a dry film resist, or a polarizing plate. It is widely used as an adhesive release film for label release paper.

  In addition, a protective film that protects the surface of polarizing films and electrical products, a packaging material film that protects the intermediate product once obtained from dust, scratches, environmental changes, and a glass plate or metal plate are stacked. Partition film (interleaf paper) used for storage and transport, cast film used as a backing sheet for producing a polymer film by applying a polymer solution, then curing and peeling it, and a carrier film for automatically supplying electronic components And so on.

  Particularly in recent years, with the widespread use of mobile communication devices represented by mobile phones and portable personal computers, portable information terminal devices, etc., in the manufacturing process of multilayer ceramic substrates, multilayer ceramic capacitors and the like used for these electronic devices, Release films for the ceramic green sheet production process are consumed in large quantities.

  However, those after use of these laminated films are hardly reused, and even if they are discarded or reused, they are used at most as fuels, and are preferable from the viewpoint of resource saving and environmental protection. Did not.

  The reason is that even if the laminated film after use is re-melted, the surface functional layer is mixed into the resin composition of the base film to be reused.

  For example, the release film for the ceramic green sheet manufacturing process described above is used in a filtration process during melt extrusion when the release film after use is melted and a new film is formed and reused. There is a problem that the filter is clogged by the ceramic remaining on the film surface, and normal film formation cannot be performed. Also, even if the ceramic can be forcibly removed by mechanical scraping or other means, the components of the release layer such as a curable silicone resin film remain on the base film and mix into the molten polymer. However, when extruded, an unpleasant odor is generated, the melt viscosity of the polymer is lowered, which may cause breakage during film formation, or even if the film can be formed, the obtained film is colored and the quality is deteriorated. Inevitable.

On the other hand, a technique for obtaining a monomer with high purity by depolymerization is known, but depolymerization requires a lot of energy to decompose from a chemically stable state, and when viewed in total energy consumption, It is hard to say that the load is small.
JP-A-5-269932 JP-A-2002-265665

  An object of the present invention is to provide a recycling method capable of reusing a laminated film, which has been difficult in the past, by a method of remelting with a small environmental load.

  That is, according to the present invention, after using a laminated film in which an easily soluble resin layer and a surface functional layer are laminated in this order on at least one surface of a base film, the resin constituting the easily soluble resin layer can be dissolved. The resin constituting the material film was washed with a solvent that did not dissolve, thereby separating and collecting the base material film or its crushed material from the laminated film, and re-melting the separated and collected material to form the base material film. A method for recycling a laminated film, comprising regenerating a resin composition.

  Further, the present invention is a recycled product comprising at least a part of a resin regenerated by the method for recycling a laminated film.

  ADVANTAGE OF THE INVENTION According to this invention, the recycling of the laminated film which was difficult conventionally can be performed by the method of small environmental load called remelting.

  The laminated film referred to in the present invention is formed by laminating an easily soluble resin layer and a surface functional layer on at least one side of a base film in this order.

  As a main polymer of the resin composition constituting the base film (hereinafter, also referred to as base film resin), polyester, polyimide, polypropylene, polyamide, polycarbonate, polyacetate, polyethylene, polyphenylene sulfide, or the like can be used. Among them, polyesters are preferred in terms of heat resistance and strength, and polyesters having polyethylene terephthalate and polyethylene naphthalate as main components, which are excellent in quality stability after reproduction, are particularly preferably used.

  The thickness of the base film may be appropriately set depending on the application, but is preferably 10 to 200 μm from the viewpoint of mechanical strength, rigidity and the like.

  It is important that the easily soluble resin layer is provided between the base film and the surface functional layer. By doing so, the laminated film after use is washed with a solvent in which the resin constituting the easily soluble resin layer (hereinafter, also simply referred to as easily soluble resin) can be dissolved and the base film resin does not dissolve. This makes it possible to dissolve the easily soluble resin in the solvent and completely separate and remove the surface functional layer and the residues and impurities attached to the surface functional layer. (Resin) alone. That is, even if the base film is pulverized and re-melted, the components of the surface functional layer, the components of the remaining impurities, and the like are not mixed, and the resin composition having extremely high purity can be regenerated.

  The easily soluble resin is preferably a water-soluble or water-dispersible resin in consideration of the load on the environment at the time of recovery. Among them, water-soluble or water-dispersible, polyester resin, polyester urethane resin, acrylic resin, ethylene ionomer resin, polyvinyl alcohol resin, polyvinylpyrrolidone resin, ethylene-vinyl alcohol resin, at least of starches Those having one type as a main component are preferred.

  As the water-soluble resin, those containing a hydrophilic functional group in the molecular structure thereof are preferable, and among them, a hydroxyl group, an ether group, an amide group, a carboxyl group, a phosphate group, a sulfonic acid group, an amino group, an imino group, Those containing at least one selected from carboxylate groups, sulfonate groups and ammonium bases are more preferred, and those containing at least one selected from hydroxyl group, carboxyl group, sulfonate group and carboxylate group are particularly preferred.

  Specific water-soluble resins include potato starch, potato starch, tapioca starch, wheat starch, carboxymethyl starch, hydroxymethyl starch, hydroxypropyl starch, cationic starch, acetate starch, octenyl succinate starch, phosphate phosphate, diphosphate phosphate. Starch, glycerol di-starch, dialdehyde starch, grafted starch, soluble starch, pregelatinized starch, corn starch, konjac, seaweed, agar, sodium alginate, troloioi, tragacanth gum, gum arabic, dextran, levan, glue, gelatin, casein, collagen , Viscose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, polyvinyl alcohol Le, sodium polyacrylate, polyethylene oxide, polyacrylamide, polyacrylic acid, and polyvinyl pyrrolidone. These may be used alone or in combination of two or more. Among them, polyvinyl alcohol, polyvinyl pyrrolidone, and starches are preferable in terms of organic solvent resistance, coating properties, and the like.

  As the polyvinyl alcohol, a saponification degree of 70 to 99 mol% and a viscosity average polymerization degree of 300 to 10000 are preferable, and a saponification degree of 75 to 90 mol% and a viscosity average polymerization degree of 300 to 2500 are more preferable. Specifically, “Poval” PVA-102, PVA-103, PVA-105, PVA-110, PVA-117, PVA-117H, PVA-120, PVA-124, PVA-CSA, PVA manufactured by Kuraray Co., Ltd. -CST, PVA-HC, PVA-203, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-217E, PVA-217EE, PVA-220E, PVA-403, PVA-405. "Gohsenol" NH manufactured by Nippon Synthetic Chemical Industry Co., Ltd., such as PVA-420, PVA-420H, L-8, L-9, L-10, PVA-505, PVA-617, PVA-613, PVA-706, etc. -26, NH-20, NH-18, N-300, NM-14, NM-11, NL-05, AH-26, AH- 2, AH-17, A-300, C-500, P-610, AL-06GH-23, GH-20, GH-17, GM-14, GM-14L, GL-05, GL-03, KH- 20, KH-17, KM-11, KL-05, KP-08, KP-06, NK-05, "Gorselan" F-78, L-0301, L-0302, L-3266, etc. are preferably used. .

  Further, the polyvinyl alcohol may be a copolymer, and in that case, a copolymerized polyvinyl alcohol having a vinyl alcohol unit of 60 mol% or more is preferably used.

  As polyvinylpyrrolidone, those having a molecular weight of 100,000 to 5,000,000 are preferable, and those having a molecular weight of 300,000 to 1,000,000 are more preferable. Specifically, PX-K30P and PX-K90P manufactured by Nippon Shokubai Co., Ltd. are preferably used.

  Specific examples of starches include "Piostarch LT", "Piostarch KY", "Piostarch K-5", "Penon JE-66", "Penon PKW", "ZP- 8 "," Petrosize L-2B "and the like are preferably used.

  Alternatively, a resin mainly composed of polyhydroxycarboxylic acid may be used as the easily soluble resin. For example, polymers such as L-lactic acid, D-lactic acid, glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 6-hydroxycaproic acid, and copolymers thereof Coalescing can be used. Among these, lactic acid homopolymer (polylactic acid), a copolymer of lactic acid and another hydroxycarboxylic acid, or a mixture thereof is particularly preferable from the viewpoint of solubility. Such an easily soluble resin may contain a dicarboxylic acid or glycol as long as the effects of the present invention are not impaired. These can be dissolved in an alkaline solution such as caustic soda or N-methyl-2-pyrrolidone.

  The thickness of the easily soluble resin layer in the laminated film is preferably from 0.01 to 10 μm, more preferably from 0.05 to 5 μm, from the viewpoint of easy dissolution in water and other solvents in the recovery step. It is.

  The material constituting the surface functional layer can be appropriately selected according to the purpose and use of the laminated film. For example, in the case of imparting releasability such as a release film for a process, a curable silicone resin as a main component, a urethane resin, a modified silicone resin by graft polymerization with an epoxy resin or the like is appropriately used. Can be selected and used. In particular, in the case of a release film for a ceramic green sheet manufacturing process, a film mainly containing a curable silicone resin is preferable. Examples of such curable silicone resins include various curing reaction types such as a solvent addition type, a solvent condensation type, a solvent ultraviolet curing type, a solventless addition type, a solventless condensation type, a solventless ultraviolet curing type, and a solventless electron beam curing type. Can be used. Specifically, LTC750A, LTC300B, SD7223, SD7223, SD7229, SRX-210, etc. manufactured by Dow Corning Toray Silicone Co., Ltd., YSR-3022, TPR-6700, TPR-6720, TPR-6721, etc. manufactured by Toshiba Silicone Co., Ltd. KS-774, KS-775, KS-778, KS-779H, KS-856, X-62-2422, X-62-2461, KNS-305, KNS-3000, X-62 manufactured by Shin-Etsu Chemical Co., Ltd. -1256 and the like are preferably used.

The coating amount of the surface functional layer can be appropriately set according to the intended use of the laminated film, but is preferably in the range of 0.01 to 10 g / m ² , more preferably 0.05 to 10 g, from the viewpoint of coating stability. 5 g / m ² .

  Next, an example of usage of the laminated film according to the present invention will be described using a release film for a ceramic green sheet manufacturing process as an example.

  As a material used for each layer of the release film for the ceramic green sheet production process, for example, a polyester film containing polyethylene terephthalate as a main component as the base film, a polyvinyl alcohol resin as the easily soluble resin layer, and a surface functional layer as the material For example, a thermosetting silicone resin can be employed.

  A ceramic slurry is applied onto the release layer surface of the release film for the process and dried, and the solvent in the slurry is removed to produce a ceramic green sheet layer having a desired thickness.

  As a method of applying the ceramic slurry, a blade coater, a die coater, a knife coater, a cast coater, or the like can be employed according to the thickness of the ceramic green sheet to be formed.

The ceramic raw material is not particularly limited, and various dielectric materials can be used. For example, oxides composed of metals such as titanium, aluminum, barium, lead, zirconium, silicon, yttrium, barium titanate, Pb (Mg _1/3 , Nb _2/3 ) O ₃ , Pb (Sm _1/2 , Nb _{1 / 2} ) O ₃ , Pb (Zn _1/3 , Nb _2/3 ) O ₃ , PbThO ₃ , PbZrO _{3 and the} like can be used. These may be used alone or as a mixture of two or more.

  As the binder used for the ceramic slurry, an aqueous polymer such as polyurethane resin, urea resin, melamine resin, epoxy resin, vinyl acetate resin, acrylic resin, polyvinyl alcohol, and polyvinyl butyral can be used. . These may be used alone or as a mixture of two or more.

  As a solvent used for the ceramic slurry, toluene, ethanol, methyl ethyl ketone, isopropyl alcohol, γ-butyl lactone and the like can be used. These may be used alone or as a mixture of two or more. Further, a plasticizer, a dispersant, an antistatic agent, a surfactant and the like may be added to the ceramic slurry as needed.

  When manufacturing a multilayer ceramic capacitor, for example, from the ceramic green sheet manufactured by the above method, the internal electrodes are screen-printed with a conductive paste or the like as necessary on the ceramic green sheet manufactured on the release film. Then, it is die-cut into a desired shape. Next, the ceramic green sheets on which the internal electrodes are printed are peeled from the release film, and the peeled ceramic green sheets are laminated by a necessary number while sucking using means such as a suction head, and then thermocompression-bonded by a press machine or the like. Thus, a ceramic laminate is produced.

  The laminate thus obtained is cut into chips in such a manner that the internal electrodes are exposed at the end faces, and this is placed in a firing furnace and fired under predetermined heating conditions. The laminated body sintered through the firing step is formed into a multilayer ceramic capacitor by applying a conductive paste or the like to an end face where the internal electrodes are exposed to form external electrodes.

  The laminated film according to the present invention is recycled after being used for applications such as a cast film, a carrier film, a protective film, and a partition film, in addition to the above-described release film for a process. An embodiment example will be described for the separation and recovery process of the base film.

  As a method of cleaning the laminated film after use, for example, when the laminated film is a continuous film shape such as wound into a roll, from the unwinding device installed in the front of the cleaning tank filled with the solvent Unwind the laminated film, guide it into the washing tank and immerse it, then wash the film in the washing tank while transporting the laminated film with a transport roll or the like provided in the washing tank, and then wash the film after washing. The drying can be performed by introducing the film into a tunnel-type oven or the like, drying the film, and winding the film by a winding device installed at the outlet of the oven. In this embodiment, a clean substrate film can be continuously collected, and it is preferable in terms of cost.

  In washing the laminated film after use, it is also preferable to perform an operation of mechanically rubbing the surface functional layer. By doing so, the surface functional layer and the easily soluble resin layer can be reliably and efficiently separated from the laminated film.

  As such a rubbing means, for example, a brush-like material, a scourer-like material, a mesh-like material, a comb-like material, a sword-like material, a polishing cloth, a sandpaper, a scraper, a protrusion-forming material, and the like can be used. Further, a plurality of rubbing means may be combined.

  When the laminated film has a continuous film shape such as wound into a roll, a metal or resin brush roll or the like is disposed at a position in contact with the transport roll, and the surface functional layer side of the laminated film is mechanically disposed. By rubbing, the cleaning effect can be enhanced. A plurality of brush rolls may be arranged.

  When using a brush roll, in order to enhance the cleaning effect, it is preferable that the rotation direction of the brush roll is opposite to the transport direction of the laminated film, and the peripheral speed (V1) of the brush roll and the transport speed of the laminated film ( The speed ratio V1 / V2 of V2) is preferably 2 or more. More preferably, V1 / V2 is set to 5 or more. The cleaning effect increases as V1 / V2 increases, but the upper limit is approximately 300.

  In order to enhance the cleaning effect, the time from the start of dipping the laminated film in the cleaning liquid to the end of the contact with the brush roll is preferably 2 seconds or more.

  It is also preferable to spray steam, high-temperature water, high-pressure water such as a jet stream, or the like on the surface functional layer surface of the laminated film in order to enhance the cleaning effect. In particular, it is also preferable to inject high-temperature and high-pressure water having high temperature and high pressure. Here, the high pressure is preferably 0.1 to 10 MPa, and the high temperature is preferably 60 to 100 ° C.

  Further, for example, after unwinding the laminated film wound into a roll from the unwinding device, and after or while spraying steam, high-temperature water, high-pressure water or high-temperature and high-pressure water on the surface functional layer forming surface, a metal or Steam, such as by mechanically rubbing the surface functional layer forming surface with a resin brush roll, or by spraying steam, high-temperature water, high-pressure water or high-temperature high-pressure water again on the rubbed film surface to wash it It is also preferable to alternately combine high-temperature water, high-pressure water or high-temperature high-pressure water jetting means with mechanical scraping means using a brush or the like.

  In cleaning the laminated film after use, ultrasonic cleaning can also be adopted.

  Further, these cleaning methods may be used in appropriate combination.

  In washing the laminated film after use, components of the surface functional layer and impurities such as residual ceramics in the release film for the ceramic green sheet manufacturing process, which are dissolved in the washing tank, are filtered by circulating the washing solvent by a filtration device. Can be removed.

  When the laminated film after use has a discontinuous shape such as a cut one, it may be crushed into flakes by a crusher and then washed with a solvent. For example, into a washing tank equipped with a stirrer, put a laminated film crushed into flakes, and after stirring and washing, scoop up the film with, for example, a wire mesh of a belt conveyor system, and then guide it to a tunnel oven or the like to heat it. After drying, a clean substrate film can be continuously collected.

  As the solvent used for washing, when the easily soluble resin is a water-soluble resin, it is preferable to use water. By performing water washing using a water-soluble resin as the easily soluble resin, the burden on the environment can be further reduced. In this case, a surfactant or the like may be added to the washing water in order to improve the wettability with the release film to be washed. The water used may be at room temperature, but is preferably used in the state of warm water or hot water at 30 ° C. to 90 ° C. in order to enhance the solubility.

  After the washing, the base film that has not yet been crushed into flakes is preferably charged into a crusher and crushed into flakes. The shape of the flakes is preferably such that one side has a length of 5 cm or less, and more preferably one side has a length of 1 cm or less. The pulverizer may be a multistage type having two or more stages in order to increase the pulverization processing capacity and processing efficiency. A crusher or a shredder may be used as a crusher.

  The ground flakes can be put into a granulator and solidified. As for the shape and size of the solid, the shape is preferably cylindrical, taking into consideration the biting property in an extruder or the like in the next step, and the size is 1 to 10 mm in diameter and 2 to 50 mm in length. Is preferred.

  Next, the granulated solid is supplied to an extruder, melt-extruded into a strand, cooled in water or the like, and continuously cut by a cutter to obtain a regenerated chip. Regenerated chips can be used as raw materials for films, fibers, and other molded products.

  The granulated solid can also be used as it is as a raw material for films, fibers, and other molded products. The film can be supplied to a conventional biaxial drawing machine to produce a film, or to a spinning machine to supply a filament. And staples and nonwoven fabrics, and supply to an injection molding machine to produce various molded products.

  Further, a granulated solid or regenerated chips may be used by mixing with a usual virgin raw material.

  Hereinafter, the present invention will be described in detail using a release film for a ceramic green sheet manufacturing process as an example, but the present invention is not limited to these examples.

<Evaluation method>
(1) Separability of Surface Functional Layer In each of Examples and Comparative Examples, the following evaluation was performed after “washing and collecting of release film after use”.
(A) When the film is in a roll shape From the last part of the winding, five cut films each measuring 5 cm in the width direction and 10 cm in the longitudinal direction were sampled. A polyester pressure-sensitive adhesive tape (Nitto Denko Corporation No. 31B) was attached to the surface of the film on which the surface functional layer was formed, and the film was peeled off by hand. Separability was determined as follows based on the degree of peeling.
：: In all of the five samples, the tape was strongly adhered and hardly peeled off.
×: At least one of the five sheets showed weak adhesion of the tape and was easily peeled off.
(B) When the film has a cut shape: A sample of 10 cut films is sampled at random, a polyester adhesive tape is stuck on each of the front and back surfaces of the film, and the film is peeled off by hand. The separability was determined.
：: The tape strongly adhered to both the front and back surfaces of the film on all 10 sheets, and the film was hard to peel.
×: At least one of the front and back surfaces of the film was weak in sticking of the tape, and even one of the ten films was easily peeled off.

  A tape with weak adhesion and easily peeled off indicates that the release layer as the surface functional layer remains without being separated.

(2) Maintainability of Intrinsic Viscosity First, the intrinsic viscosity [η] of the resin composition was measured at 25 ° C. using orthochlorophenol as a solvent.

The intrinsic viscosity of the resin composition used as the raw material of the base film is [η ₁ ], the intrinsic viscosity of the regenerated resin composition is [η ₂ ], and the reduction rate (%) of the intrinsic viscosity of the regenerated chip is calculated by the following equation. It was determined as follows.
Reduction rate (%) = {([η ₁ ] − [η ₂ ]) / [η ₁ ]} × 100
A: The reduction rate is 5% or less.
：: The reduction rate is more than 5% and 10% or less.
Δ: The reduction rate is more than 10% and 15% or less.
X: The reduction rate exceeds 15%.
If it is Δ, ○, ◎, it is passed as a recycled product.
In Table 1, "maintain viscosity" is indicated.

(3) Color Tone A colorless and transparent cylindrical cell (part number 2301, inner diameter 31 mm, depth 15 mm) attached to the apparatus using a spectroscopic color difference meter SE-2000 (manufactured by Nippon Denshoku Industries Co., Ltd.) , And the X, Y, and Z values as color tristimulus values were measured under optical conditions in accordance with JIS Z 8722, and the color tone b value defined in JIS Z 8730 was determined. .

The b value of the chip color tone b1 of the resin composition used as the raw material of the base film was b1 and the b value of the regenerated chip was b2, and the change (Δb) in the color tone was determined by the following equation.
Δb = | b2-b1 |
A: Δb is 1 or less.
：: Δb is more than 1 and 2 or less.
Δ: Δb is more than 2 and 3 or less.
X: Δb exceeds 3.
If it is Δ, ○, ◎, it is passed as a recycled product.

(4) Transparency 2 g of the resin composition was dissolved in 20 ml of a mixed solvent of phenol / carbon tetrachloride (weight ratio 6: 4), and the solution haze H (%) was measured by ASTM-D-1003-52.

The solution haze of the resin composition used as the raw material of the base film was H1, the solution haze of the regenerated chip was H2, and the change in haze (ΔH) was determined by the following equation.
ΔH = | H2-H1 |
A: ΔH is 5% or less.
：: ΔH is more than 5% and 10% or less.
Δ: ΔH is more than 10% and 15% or less.
×: ΔH exceeds 15%.
If it is Δ, ○, ◎, it is passed as a recycled product.

[Example 1]
(Preparation of laminated film)
(Base film)
A polyethylene terephthalate chip (intrinsic viscosity [η ₁ ] = 0.63) was extruded from a T-die die and cast on a cast drum having a surface temperature of 25 ° C. to obtain an unstretched film.

  The unstretched film was guided to a roll-type stretching machine, preheated by a preheating roll at 85 ° C, stretched 3.3 times in the longitudinal direction between rolls having a peripheral speed difference of 95 ° C, and once cooled to room temperature. .

  Next, it is fed into a tenter type horizontal stretching machine, stretched 3.5 times in the width direction at a temperature of 95 ° C., and further subjected to a heat treatment in a heat treatment zone of a tenter in an atmosphere of 220 ° C. for 10 seconds to be biaxially stretched to a thickness of 38 μm. A film was prepared and used as a base film.

(Easily soluble resin layer)
A 5% by weight aqueous solution of a polyvinyl alcohol resin (Nippon Synthetic Chemical Industry Co., Ltd. “Gohselan” L-3266) was applied to one surface of the base film with a gravure coater at a coating amount of 0.2 g / m ² after drying. Coating. This was dried at 120 ° C. in a tunnel oven to form an easily soluble resin layer made of a water-soluble resin.

(Surface functional layer)
Using a gravure coater, a 5% by weight toluene solution of a curable silicone resin (1 part by weight of Toray Dow Corning Silicone Co., Ltd. LTC-300B; 100 parts by weight of Toray Dow Corning Silicone Co., Ltd. and SRC-212 manufactured by Toray Dow Corning Silicone) was added Coating was performed on the easily soluble resin layer so that the coating amount after drying was 0.2 g / m ² . This was heated at 140 ° C. in a tunnel oven to form a release layer as a surface functional layer, and wound into a roll. Thus, a laminated film (release film) was produced.

(Preparation of ceramic green sheet)
A ceramic slurry having the following composition was uniformly applied on a release layer surface of the laminated film by a blade coater. This was dried at 85 ° C. in a tunnel oven to produce a 20 μm thick ceramic green sheet on a release film.

(Ceramic slurry composition)
Ceramic powder (barium titanate): 100 parts by weight Binder (polyvinyl butyral): 10 parts by weight Plasticizer (dioctyl phthalate): 5 parts by weight Solvent (toluene / isopropyl alcohol = 1/1 (weight ratio))
: 100 parts by weight.

(Removal of ceramic green sheet)
After slitting the ceramic green sheet on the release film into a shape of 10 cm × 10 cm with a cutting blade, the ceramic green sheet was suctioned by a vacuum suction machine and peeled off from the release film. The release film was wound up while scraping the ceramic portion remaining on the release film surface with a scraper.

(Washing and collection of release film after use)
The rolled release film was set on an unwinding machine, guided in a hot water bath at 60 ° C., immersed and transported in the bathtub, and washed by brushing the release layer surface with a resin brush roll. At this time, the peripheral speed (V1) of the brush roll was 150 m / min, and the transport speed (V2) of the film was 30 m / min. The V1 / V2 ratio becomes 5. The time from the start of immersion of the release film in warm water to the end of contact with the brush roll (referred to as immersion time in Table 1) was 6 seconds.
The washed film surface was air blown at the outlet of the bath to remove water droplets, guided to a tunnel oven, dried at 120 ° C., and continuously wound at the outlet of the oven to collect a base film.

  The separability of the recovered rolled film was ○.

(Granulation)
The collected roll-shaped film was pulverized into about 5 mm square with a crusher, and then solidified into a cylinder having a diameter of about 5 mm and a length of 20 mm using a granulator.

(Tip playback)
After the solid was vacuum-dried, it was supplied to an extruder having a screw diameter of 30 mm and re-melted to obtain chips again.

  The quality of the obtained chips was as shown in Table 1.

[Example 2]
(Preparation of laminated film)
(Base film)
It was the same as in Example 1. However, after stretching and cooling in the longitudinal direction, and further subjected to corona discharge treatment, the following readily soluble resin layer was formed before the entrance of the tenter type transverse stretching machine.

(Easily soluble resin layer)
A 5% by weight aqueous solution of polyvinyl alcohol (“Gohsenol” KH-17, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was applied to one surface of the base film in the middle of the production with a bar coater at a dry weight of 0.3 g / m 2. It was coated so that ² to form the easily soluble resin layer.

(Surface functional layer)
A 2% by weight toluene solution of a curable silicone resin (1 part by weight of Toray Dow Corning Silicone Co., Ltd. LTC-750A; 100 parts by weight of Toray Dow Corning Silicone Co., Ltd.) was added using a bar coater. On the easily soluble resin layer, coating was performed so that the weight after drying was 0.15 g / m ² . This was heated and cured at 140 ° C. in a hot air oven to form a release layer.

  Thereafter, in the same manner as in Example 1, chips of the regenerated resin composition were obtained.

  The separability of the recovered rolled film was ○.

  The quality of the obtained chips was as shown in Table 1.

[Examples 3 to 5]
Example 2 was repeated except that the V1 / V2 ratio was changed as shown in Table 1 by changing the peripheral speed of the brush roll in "Cleaning and Recovery of Release Film After Use".

  The separability of the recovered rolled film was ○.

  The quality of the obtained chips was as shown in Table 1.

[Examples 6 to 8]
In "Cleaning and recovery of release film after use", the time from the start of immersing the release film in warm water to the end of contact with the brush roll (referred to as immersion time in Table 1) was changed. Example 2 was repeated except for the above.

  The separability of the recovered rolled film was ○.

  The quality of the obtained chips was as shown in Table 1.

[Example 9]
(Preparation of laminated film)
It was produced in the same manner as in Example 2.

(Preparation of ceramic green sheet)
Performed in the same manner as in Example 1.

(Removal of ceramic green sheet)
Performed in the same manner as in Example 1.

(Washing and collection of release film after use)
The release film obtained by peeling and winding the ceramic green sheet was cut into a size of 6 mm × 20 mm, placed in a hot water bath at 60 ° C., washed with stirring for 5 minutes, rinsed, and dehydrated with a centrifuge. Then, the film was further dried in a hot air oven to collect a film.

  The separability of the cut film collected was ○.

(Granulation)
The collected cut film was solidified into a cylinder having a diameter of about 5 mm and a length of 20 mm using a granulator.

(Tip playback)
Performed in the same manner as in Example 1.

  The quality of the obtained chips was as shown in Table 1.

[Example 10]
(Preparation of laminated film)
(Base film)
It was the same as in Example 1. However, after stretching and cooling in the longitudinal direction, and further subjected to corona discharge treatment, the following readily soluble resin layer was formed before the entrance of the tenter type transverse stretching machine.

(Easily soluble resin layer)
A 5% by weight aqueous solution of polyvinyl alcohol (Kuraray “Poval” PVA-405) is applied to one surface of the base film in the middle of the preparation with a bar coater to a weight of 0.2 g / m ² after drying. To form a readily soluble resin layer.

(Surface functional layer)
A release layer was formed in the same manner as in Example 2.

(Preparation of ceramic green sheet)
Performed in the same manner as in Example 1.

(Removal of ceramic green sheet)
Performed in the same manner as in Example 1.

(Washing and collection of release film after use)
The rolled release film was set on an unwinder, unwound, immersed once in a hot water bath at 80 ° C, pulled up outside the hot water tank, and steam with a vapor pressure of 0.5 MPa was applied to the release layer forming surface. Sprayed. Next, the release layer forming surface was brushed with a first polybutylene terephthalate resin brush roll, and immersed again in a hot water tank. Next, when the film exited the hot water bath, the film was brushed with a second polybutylene terephthalate resin brush roll while spraying high-temperature and high-pressure water at a temperature of 80 ° C. and a pressure of 0.3 MPa. Thereafter, the film surface was air blown to remove water droplets, guided into a tunnel oven, dried at 120 ° C., and continuously wound up at the outlet of the oven to collect a base film. At this time, the peripheral speed (V1) of the first and second brush rolls was 150 m / min, and the transport speed (V2) of the film was 50 m / min. The V1 / V2 ratio is 3.

  The separability of the recovered rolled film was ○.

(Granulation)
Performed in the same manner as in Example 1.

(Tip playback)
Performed in the same manner as in Example 1.

  The quality of the obtained chips was as shown in Table 1.

[Comparative Example 1]
(Preparation of laminated film)
Except not having provided the easily soluble resin layer, it carried out similarly to Example 1.

(Preparation of ceramic green sheet)
Performed in the same manner as in Example 1.

(Removal of ceramic green sheet)
Performed in the same manner as in Example 1.

(Washing and collection of release film after use)
Performed in the same manner as in Example 1.

  The separability of the recovered rolled film was x.

(Granulation)
The collected roll-shaped film was pulverized, and granulation was attempted by a granulator. However, the obtained film was not formed into a target cylindrical shape, but became a solid having an irregular shape.

(Tip playback)
The solid was vacuum-dried, supplied to an extruder having a screw diameter of 30 mm, and re-melted. When re-chip formation was attempted, bubbles were mixed in the molten polymer and stable extrusion could not be performed.

  The barely obtained chip quality was as shown in Table 1.

[Comparative Example 2]
In "Washing and recovery of release film after use", the same trial as in Comparative Example 1 was performed, except that a 60 ° C, 0.5N caustic soda aqueous solution was used instead of hot water at 60 ° C.

  The separability of the recovered rolled film was x.

  In the “granulation”, the target did not have a cylindrical shape, but became a solid having an irregular shape.

  In "chip regeneration", bubbles were mixed in the molten polymer, and stable extrusion could not be performed.

  The barely obtained chip quality was as shown in Table 1.

[Comparative Example 3]
In "Washing and recovery of release film after use", the same trial as in Comparative Example 1 was performed, except that the N-methyl-2-pyrrolidone solution at 60C was used instead of hot water at 60C.

  The separability of the recovered rolled film was x.

  In the “granulation”, the target did not have a cylindrical shape, but became a solid having an irregular shape.

  In "chip regeneration", bubbles were mixed in the molten polymer, and stable extrusion could not be performed.

  The barely obtained chip quality was as shown in Table 1.

Claims (13)

After using a laminated film obtained by laminating an easily soluble resin layer and a surface functional layer on at least one side of the base film in this order, the resin constituting the easily soluble resin layer is soluble and constitutes the base film. By washing with a solvent that does not dissolve the resin, the base film or its pulverized product is separated and collected from the laminated film, and the separated and collected product is re-melted to regenerate the resin composition constituting the base film. A method of recycling a laminated film. The method for recycling a laminated film according to claim 1, wherein the washing of the laminated film after use with a solvent includes an operation of mechanically rubbing the surface functional layer. The rubbing means is at least one of a brush, a brush, a mesh, a comb, a sword, a polishing cloth, a sandpaper, a scraper, and a projection. 3. The method for recycling a laminated film according to 1 or 2. The method for recycling a laminated film according to claim 3, wherein the form after use of the laminated film is a continuous film shape, and washing with a solvent is performed by a brush roll. When the rotation direction of the brush roll is opposite to the transport direction of the laminated film, and the peripheral speed of the brush roll is V1 and the transport speed of the laminated film is V2, the ratio V1 / V2 between the two is 2 or more. 5. The method for recycling a laminated film according to claim 4, wherein: The laminate according to any one of claims 1 to 3, wherein the used form of the laminated film is a discontinuous shape, and the used film is washed with a solvent after being pulverized into flakes by a pulverizer. How to recycle film. The method for recycling a laminated film according to any one of claims 1 to 6, wherein the resin constituting the base film is mainly composed of polyester. The method for recycling a laminated film according to any one of claims 1 to 7, wherein the resin constituting the easily soluble resin layer is a water-soluble resin. The method for recycling a laminated film according to any one of claims 1 to 8, wherein the surface functional layer is a release layer made of a curable silicone resin. The method for recycling a laminated film according to any one of claims 1 to 9, wherein the solvent is water. The method for recycling a laminated film according to claim 10, wherein the washing of the laminated film after use includes an operation of spraying steam or high-temperature water or high-pressure water to the surface functional layer. The method for recycling a laminated film according to any one of claims 1 to 11, wherein the laminated film is a release film used in a ceramic green sheet manufacturing process. A recycled product comprising, at least in part, a resin regenerated by the method for recycling a laminated film according to claim 1.