Method for separating and recovering laminated film

Abstract

To provide a method for efficiently separating and recovering a resin substrate from a laminated film without preventing exposure of separation layers of shredded surfaces.SOLUTION: A method for separating and recovering a laminated film having at least a resin substrate layer and a separation layer comprises: (1) shredding step for shredding the laminated film while cooling the same with water cooled to liquid temperature of 50°C or lower using cooling means to obtain shredded articles; (2) separation step for immersing the shredded articles into a separation liquid to separate the resin substrate layer; and (3) recovering step for recovering the separated resin substrate layer.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for separating and recovering a laminate film having at least a resin substrate layer and a release layer in contact with the resin substrate layer. [Background technology]

[0002] In recent years, packaging, plastic bottles, and other plastic products made from plastic film have become a problem as a cause of environmental pollution, and regulations on waste plastics are becoming stricter. For example, when these plastic products are discarded or dumped as marine litter, they decompose in seawater and become submicron-sized fragments (microplastics), which float in the seawater. If marine organisms such as fish ingest the plastics, they will accumulate in their bodies, and there is concern that they will affect the health of seabirds and humans who consume the marine organisms as food.

[0003] Examples of the plastic products include food packaging packages using plastic substrates. The laminated films used in the packages are generally formed by providing a printing layer using gravure ink, flexographic ink, or other printing ink on various plastic substrates such as polyester (PET) substrates, nylon (NY) substrates, and polypropylene (PP) substrates. The laminated film may be further bonded to a sealant substrate via an adhesive or the like, and a laminated film having a wide variety of configurations is appropriately selected and used depending on the application and contents.

[0004] As an attempt to solve the environmental problems caused by plastics, for example, Patent Document 1 discloses the recovery of a sealant substrate from a laminated film by using an adhesive having alkali-release properties. However, such separation of a laminated film is greatly influenced by the contact state between the release layer and the alkaline solution, and it is important to consider how the release layer is exposed from the end face of the laminated film.

[0005] As a shredding method used in the recycling process of plastic waste materials that does not involve separation of films, for example, Patent Document 2 describes a method in which a shredder with fixed and rotating blades is used to dry shred the materials by using the shear force between the rotating and fixed blades. Furthermore, for example, Patent Document 3 describes that waste plastics such as used bottles can be crushed and washed with water at the same time, thereby efficiently cleaning dirt from the inside and outside of the bottles in a short time.

[0006] As a method for separating and recovering a laminated film, for example, Patent Document 4 describes a recycling system in which the laminate is crushed in water or a detergent and separated into single layers. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2020 / 111226 [Patent Document 2] Japanese Patent Application Publication No. 10-137615 [Patent Document 3] JP 2002-200433 A [Patent Document 4] International Publication No. 2021 / 230033 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the case of laminated films containing plastic substrates, the heat generated during shredding can cause the plastic to break down. Therefore, in the method described in Patent Document 2, the release layer is not exposed and cannot come into contact with the alkaline solution, resulting in a significant decrease in the efficiency of separation of the laminated film. In addition, the method described in Patent Document 3 is intended to wash and crush thick waste plastics such as PET bottles for reuse, and does not describe shredding laminated films. In addition, Patent Document 3 is intended to wash and remove dirt such as sugar attached to the surface of waste plastics, and it is generally believed that the higher the temperature of the washing water, the better the washing efficiency. Furthermore, since the method of Patent Document 3 does not include a process of removing the ink layer, adhesive layer, etc., and a process of recovering the substrate after removal, the obtained recycled plastic has low mechanical properties or is dark in color, and the scope of recyclable application is limited. In addition, in the method described in Patent Document 4, since separation is performed by the shear force of crushing, it is necessary to increase the residence time and stirring force in the stirring section of the crushing device in order to realize separation performance. Under such strong crushing conditions, a large amount of fine pieces of the laminated film that are finely divided by excessive shearing are generated and dispersed in water, which makes it difficult to separate and recover the ink pieces and cleaning solution. In addition, in the method described in Patent Document 4, ink pieces and adhesive pieces generated during crushing and separation adhere and accumulate in the crushing device and on the resin substrate, and as in Patent Document 3, there is a problem that the quality of the obtained recycled plastic is reduced. Furthermore, Patent Document 4 describes that the liquid temperature of the water or cleaning agent used is preferably high in order to efficiently peel and remove the ink layer and the like provided on the laminate.

[0009] That is, Patent Document 1 does not describe in detail a method for shredding the laminated film, and when the laminated film described in Patent Document 1 is shredded in large quantities using the conventional methods described in Patent Documents 2 to 4 assuming an actual recycling process, there is a problem that the laminated film will be generated with the release layer not exposed and not separated, or ink particles generated during shredding will adhere to and accumulate on the substrate, thereby degrading the quality of the recycled plastic. Furthermore, there has not yet been reported a highly practical method for separating and recovering laminated films, which suppresses fusion of the resin substrate layer at the cross section during shredding by cooling with water adjusted to a liquid temperature of 50°C or less using a cooling means, and efficiently peels it off from the release layer.

[0010] That is, an object of the present invention is to provide a method for efficiently separating and recovering a resin substrate without preventing exposure of the detached layer of the thin cross section. [Means for solving the problem]

[0011] A method for separating and recovering a laminate film according to one embodiment of the present invention is a method for separating and recovering a laminate film having at least a resin substrate layer and a release layer, and is characterized by having the following steps (1) to (3). (1) A shredding process in which the laminated film is shredded while being cooled with water whose liquid temperature is set to 50° C. or less using a cooling means to obtain shredded material. (2) A separation step in which the shredded material is immersed in a release liquid to separate the resin substrate layer. (3) A recovery step of recovering the separated resin substrate layer

[0012] The method for separating and recovering a laminated film according to one embodiment of the present invention is characterized by having the following step (4) between the steps (1) and (2): (4) A washing and filtering step in which the shredded material is washed with water to remove fine particles.

[0013] The method for separating and recovering a laminated film according to one embodiment of the present invention is characterized in that the step (4) comprises filtering using a filter screen.

[0014] The method for separating and recovering a laminated film according to one embodiment of the present invention is characterized in that the mass of water used in the shredding step is 2 to 500 times the mass of the laminated film.

[0015] In one aspect of the method for separating and recovering a laminated film of the present invention, the detachment layer is a layer containing a compound having an acidic group.

[0016] In the method for separating and recovering a laminated film according to one aspect of the present invention, the detachment layer is a layer containing a water-soluble resin.

[0017] A method for separating and recovering a laminated film according to one embodiment of the present invention is characterized in that the laminated film has a partial structure having a resin substrate layer, a primer layer, and an ink layer in this order, and the primer layer is a detachment layer.

[0018] A method for separating and recovering a laminated film according to one embodiment of the present invention is characterized in that the laminated film has a partial structure in which two resin substrate layers are laminated via an adhesive layer, and the adhesive layer is a release layer.

[0019] A method for separating and recovering a laminated film according to one embodiment of the present invention is characterized in that the laminated film has a partial structure having a resin substrate layer and an ink layer in this order, and the ink layer is a detachment layer. Effect of the Invention

[0020] According to the present invention, in a laminate film having at least a resin substrate layer and a release layer, a method for efficiently separating and recovering a resin substrate can be provided without preventing exposure of the release layer in a thin cross section. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The present invention relates to a method for separating and recovering a laminate film having at least a resin substrate layer and a release layer, the method being characterized by sequentially carrying out the following steps (1) to (3). (1) A shredding process in which the laminated film is shredded while being cooled with water whose liquid temperature is set to 50° C. or less using a cooling means to obtain shredded material. (2) A separation step in which the shredded material is immersed in a release liquid to separate the resin substrate layer. (3) A recovery step of recovering the separated resin substrate layer By cutting the laminated film while cooling it with water at a liquid temperature of 50° C. or less using a cooling means, it is possible to prevent the cross section of the detachment layer from being covered by fusion of the resin substrate layer in the thin cross section. In addition, the detachment layer in the cut laminated film is suitably exposed, so that the resin substrate and the detachment layer can be efficiently separated and the resin substrate can be recovered. In addition, by carrying out steps (1) and (2) sequentially, i.e., separately rather than simultaneously, it is possible to prevent impurities such as ink particles generated in step (1) from being mixed into step (2). This makes it possible to prevent impurities such as ink particles from adhering to and accumulating on the resin substrate, and to obtain high-quality recycled plastic. Furthermore, since the resin substrate layer can be separated and recovered without excessively pulverizing the laminated film, it is possible to improve the separation and recovery of the resin substrate. The present invention will be described in detail below, but these are merely examples of the embodiments of the present invention, and the present invention is not limited to these details as long as it does not depart from the gist of the present invention.

[0022] <Laminated film> The laminated film in the present invention has at least a resin substrate layer and a release layer, and the release layer is disposed in contact with the resin substrate layer. The resin substrate layer represents the substrate recovered after the separation step, and the release layer is released (also referred to as peeled) from the resin substrate layer by immersing in a release liquid, and plays a role in contributing to the separation of the resin substrate layer.

[0023] <Detachment layer> The detachment layer in the present invention may be any layer that can be detached from the resin substrate by a known detachment liquid, and is preferably a layer containing a water-soluble resin, a layer containing a compound having an acidic group (excluding water-soluble resins), a metal vapor deposition layer, or an inorganic oxide (metal oxide) vapor deposition layer. From the viewpoint of substrate versatility, the detachment layer is more preferably a layer containing a compound having an acidic group. Also, from the viewpoint of reducing environmental load, the detachment layer is more preferably a layer containing a water-soluble resin.

[0024] When the release layer is a metal vapor-deposited layer or an inorganic oxide (metal oxide) vapor-deposited layer, the vapor-deposited layer is preferably formed on a resin substrate. When the release layer is a layer containing a water-soluble resin or a layer containing a compound having an acidic group, the release layer is a layer in contact with the resin substrate layer, and is therefore preferably at least one layer selected from the group consisting of a primer layer, an ink layer, and an adhesive layer. That is, it is preferable that at least one layer selected from the group consisting of a primer layer, an ink layer, and an adhesive layer is a layer containing a water-soluble resin or a compound having an acidic group. The compound having an acidic group may be a resin or a low molecular weight compound. These water-soluble resins or compounds having an acidic group may be used alone or in combination of two or more.

[0025] At least one layer selected from the group consisting of the primer layer, the ink layer and the adhesive layer may contain a resin component (hereinafter also referred to as a binder resin) constituting the layer, which may contain a water-soluble resin or a resin having an acidic group, or may contain a binder resin and a low molecular weight compound having an acidic group. The cases where the release layer is a primer layer, an ink layer and an adhesive layer will be described below.

[0026] [Removable primer layer] When the release layer is a primer layer, the primer layer is disposed in contact with the resin substrate and plays a role in releasing the resin substrate by dissolution, peeling, etc. with a release liquid. The primer layer preferably contains a water-soluble resin or a compound having an acidic group.

[0027] (Water-soluble resin) The water-soluble resin may be any resin that can swell or dissolve in water and be removed from the resin substrate. The water may be heated to a temperature of about 25 to 100° C. This allows the primer layer to be removed by water (including warm water). Such resins can be selected from known resins as long as they do not impair water solubility, and examples thereof include water-soluble polyester resins, water-soluble polyamide resins, water-soluble polyimide resins, water-soluble acrylic resins, water-soluble polyurethane resins, water-soluble polyallylamine resins, water-soluble phenolic resins, water-soluble epoxy resins, water-soluble phenoxy resins, water-soluble urea resins, water-soluble melamine resins, polyvinyl alcohol resins, and modified products of these resins. These can be used alone or in combination of two or more. Among them, polyvinyl alcohol (PVA) resins are preferably used from the viewpoints of availability and release properties. When the water-soluble resin has film-forming properties, the water-soluble resin may be used as the binder resin constituting the primer layer.

[0028] As the polyvinyl alcohol resin, in addition to unmodified polyvinyl alcohol, modified polyvinyl alcohol obtained by copolymerizing various monomers during the production of vinyl ester resin and saponifying the copolymer, or various post-modified polyvinyl alcohols obtained by introducing various functional groups into unmodified polyvinyl alcohol by post-modification may be used. Modified polyvinyl alcohols may also be used. These modifications are carried out by increasing the water solubility of the polyvinyl alcohol resin. can be carried out as long as it is not impaired. These resins may be used alone or in combination of two or more.

[0029] Preferred examples of polyvinyl alcohol resins include resins containing structural units having a primary hydroxyl group in the side chain, and ethylene-modified polyvinyl alcohol resins. Among them, polyvinyl alcohol resins containing structural units having a primary hydroxyl group in the side chain are preferred because of their excellent water solubility. The number of primary hydroxyl groups in these structural units is usually 1 to 5, preferably 1 to 2, and more preferably 1. In addition to the primary hydroxyl groups, it is also preferred that the structural units have a secondary hydroxyl group.

[0030] The saponification degree of the polyvinyl alcohol resin used in the present invention (measured according to JIS K 6726) is usually 60 to 100 mol%. The preferred range of the saponification degree varies depending on the modified species. For example, in the case of an unmodified polyvinyl alcohol resin, it is usually 60 to 99.9 mol%, preferably 70 to 99.0 mol%, more preferably 75 to 98.5%. The saponification degree of the modified polyvinyl alcohol resin containing a side chain 1,2-diol structural unit is usually 60 to 99.9 mol%, preferably 65 to 99.8 mol%, more preferably 70 to 99.5 mol%. If the saponification degree is too low, the water solubility tends to decrease. The saponification degree of the ethylene-modified polyvinyl alcohol resin modified with a small amount of ethylene is usually 60 mol% or more, preferably 70 to 99.5 mol%, particularly preferably 75 to 99.0 mol%. The saponification degree within the above range is preferable because it provides excellent water solubility and good releasability, and is also preferable because it provides excellent coatability when forming a primer layer.

[0031] The average degree of polymerization of the polyvinyl alcohol resin (measured in accordance with JIS K 6726) is usually 100-3,000, preferably 150-2,000, more preferably 180-1,000, and particularly preferably 200-800.

[0032] (Compounds having an acidic group) The compound having an acidic group may be a resin having an acidic group or a low molecular weight compound having an acidic group, which allows the primer layer to be removed by the above-mentioned basic aqueous solution.

[0033] Examples of the resin having an acidic group include a cellulose resin, a urethane resin, a polyamide resin, a vinyl chloride / vinyl acetate copolymer, a ketone resin, a polyester resin, and a (meth)acrylic resin. Examples of the acidic group include a carboxy group, a phosphoric acid group, a sulfo group, a sulfino group, and the like, or an ester or salt thereof. Furthermore, as the resin having an acidic group, a rosin-modified resin having an acid value, such as maleic rosin or fumaric rosin, can be used. In addition, examples of resins having an acidic group that can be used include radical copolymers such as styrene-(meth)acrylic resins, styrene-maleic acid (anhydride) resins, and terpene-maleic acid (anhydride) resins, which are copolymerized with polymerizable monomers having an acidic group, such as polymerizable monomers having a carboxy group, such as itaconic acid, maleic acid, fumaric acid, and cinnamic acid; polymerizable monomers which are acid anhydrides, such as itaconic acid anhydride and maleic acid anhydride; polymerizable monomers having a sulfonic acid group, such as sulfonated styrene; and polymerizable monomers having a sulfonamide group, such as vinylbenzenesulfonamide; and acid-modified polyolefin resins. These may be used alone or in combination of two or more.

[0034] The low molecular weight compound having an acidic group refers to a compound that does not have a molecular weight distribution and has a molecular weight of 1,000 or less. Examples of such compounds include saturated fatty acids such as lauric acid, myristic acid, palmitic acid, margaric acid, and stearic acid; oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, soybean acid, and the like. Examples of suitable carboxylic acids include unsaturated fatty acids such as pyruvic acid, pyromellitic acid, and pyromellitic anhydride; hydroxy acids such as lactic acid, malic acid, and citric acid; aromatic carboxylic acids such as benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, gallic acid, mellitic acid, and cinnamic acid; dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, and maleic acid; tricarboxylic acids such as aconitic acid; oxocarboxylic acids such as pyruvic acid and oxaloacetic acid; carboxylic acid derivatives such as amino acids and nitrocarboxylic acids; and acid anhydrides such as trimellitic anhydride and pyromellitic anhydride. The low molecular weight compound having an acidic group can be used in combination with the above-mentioned resin having an acidic group or a known binder resin constituting a known primer layer to form a primer layer.

[0035] From the viewpoint of recoating suitability, the primer layer preferably contains a compound having an acidic group, and from the viewpoint of printability, the primer layer preferably contains a urethane resin having an acidic group, an acrylic resin having an acidic group, or a rosin-modified resin.

[0036] [Urethane resin having acidic groups] The urethane resin having an acidic group is not particularly limited, and examples thereof include a urethane resin obtained by reacting a polyol having an acidic group with a polyisocyanate, a resin obtained by acid-modifying hydroxyl groups in a urethane resin obtained by reacting a polyol with a polyisocyanate, and a resin obtained by acid-modifying amino groups in a urethane urea resin obtained by reacting a polyamine with an isocyanate group in a urethane resin obtained by reacting a polyol with a polyisocyanate. In addition, as the urethane resin having an acidic group, a resin obtained by reacting a polyol containing a hydroxy acid with a polyisocyanate may be used. By using a hydroxy acid as the polyol, it is possible to impart an acid value derived from a carboxy group to the urethane resin, and it is possible to improve the releasability. In addition, when the urethane resin having an acidic group has an isocyanate group, a polyamine may be reacted with a part of the isocyanate group to introduce a urea bond, thereby forming a urethane urea.

[0037] Polyol Polyol is a general term for a compound having at least two hydroxyl groups in one molecule. The number average molecular weight of the polyol is preferably 500 to 10,000, more preferably 1,000 to 5,000. The number average molecular weight is calculated from the hydroxyl value of the polyol, and the hydroxyl value refers to a value measured according to JIS K0070. When the number average molecular weight of the polyol is 500 or more, the flexibility of the primer layer is excellent and the adhesion to the polyolefin substrate is improved. When the number average molecular weight is 10,000 or less, the blocking resistance to the polyolefin substrate is excellent.

[0038] The polyol is not particularly limited, and more preferably, at least one polyol selected from the group consisting of polyester polyol, polyether polyol, and polycarbonate polyol is used. The polyol may further include other dimer diol, hydrogenated dimer diol, castor oil modified polyol, etc. That is, the urethane resin preferably contains a structural unit derived from at least one polyol selected from the group consisting of polyester polyol, polyether polyol, and polycarbonate polyol. Since the ester bond site of the polyester polyol is hydrolyzed by alkali to improve the releasability, the urethane resin more preferably contains a structural unit derived from a polyester polyol. The content of the structural units derived from polyol is preferably 10 to 75% by mass, more preferably 15 to 70% by mass, and even more preferably 20 to 65% by mass, based on the total amount of the urethane resin. The content of the structural units derived from polyester polyol is preferably 5% by mass or more, more preferably 30% by mass or more, even more preferably 60% by mass or more, and particularly preferably 80% by mass or more, based on the total amount of the structural units derived from polyol.

[0039] Hydroxy acids The polyol may contain a hydroxy acid. The hydroxy acid refers to a compound having both a hydroxyl group, which is an active hydrogen group, and an acidic functional group in one molecule. The acidic functional group refers to a functional group that can be neutralized with potassium hydroxide when measuring the acid value, and specifically includes a carboxy group and a sulfonic acid group, and is preferably a carboxy group. As such a hydroxy acid, for example, dimethylolalkanoic acid such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and 2,2-dimethylolvaleric acid is preferably used.

[0040] <Polyisocyanate> The polyisocyanate is not particularly limited and can be selected from conventionally known polyisocyanates. It preferably contains a diisocyanate or triisocyanate, and more preferably contains an aromatic, aliphatic or alicyclic diisocyanate. These may be used alone or in combination of two or more kinds.

[0041] Polyamines The polyamine for forming the urethane urea is not particularly limited, and is preferably a diamine compound. A diamine having a hydroxyl group may be used because it can introduce a hydroxyl group into the urethane resin.

[0042] The acid value of the urethane resin having an acidic group is preferably 15 mgKOH / g or more. It is more preferably 15 to 70 mgKOH / g, and further preferably 20 to 50 mgKOH / g. When it is 15 mgKOH / g or more, the desorption property by the desorption liquid becomes good, and therefore it is preferable. The hydroxyl value of the urethane resin is preferably 1 to 35 mgKOH / g, more preferably 10 to 30 mgKOH / g. A hydroxyl value of 1 mgKOH / g or more is preferable because the release property by the release solution is good, and a hydroxyl value of 35 mgKOH / g or less is preferable because the release property by the release solution is good.

[0043] The weight average molecular weight of the urethane resin having an acidic group is preferably 10,000 to 100,000, more preferably 15,000 to 70,000, and even more preferably 15,000 to 50,000. The molecular weight distribution (Mw / Mn) of the urethane resin is preferably 6 or less. Mw represents the weight average molecular weight, and Mn represents the number average molecular weight. When the molecular weight distribution is 6 or less, the releasability, drying property of the primer composition, and retort resistance are excellent. In addition, the smaller the molecular weight distribution, that is, the sharper the molecular weight distribution, the more uniform the dissolution and peeling action by the release liquid occurs, and the more the releasability of the resin substrate is improved. The molecular weight distribution is more preferably 5 or less, and even more preferably 4 or less. In addition, the molecular weight distribution is preferably 1.5 or more, and more preferably 1.2 or more. In this specification, Mw, Mn and molecular weight distribution (Mw / Mn) are polystyrene equivalent values ​​determined by gel permeation chromatography (GPC).

[0044] The urethane resin having an acidic group may have an amine value. When the urethane resin has an amine value, the amine value is preferably 0.1 to 20 mgKOH / g, and more preferably 1 to 10 mgKOH / g. When the amine value is within the above range, the adhesion to the substrate is excellent.

[0045] The number of urethane bonds in the polyurethane resin having an acidic group is preferably 1 to 3 mmol / g, more preferably 1.5 to 2 mmol / g. The number of urea bonds is preferably 0 to 3 mmol / g, more preferably 0.2 to 1 mmol / g. The total number of urethane bonds and urea bonds is preferably 1 to 6 mmol / g, more preferably 1.7 to 3 mmol / g. By setting the number of urethane bonds and the number of urea bonds within the corresponding ranges, releasability and adhesion to substrates are improved.

[0046] [Acrylic resin having acidic group] Examples of acrylic resins having an acidic group include polymers obtained by polymerizing a monomer containing a (meth)acrylic monomer having an acidic group, such as (meth)acrylic acid or maleic acid; and resins obtained by polymerizing a monomer containing a (meth)acrylic monomer having a hydroxyl group or a glycidyl group, and then modifying the functional group to introduce a carboxyl group (e.g., maleic anhydride modified resin). The acid value of the acrylic resin having an acidic group is preferably 50 mgKOH / g or more, and more preferably 100 mgKOH / g or more.

[0047] [Rosin-modified resin] Rosin-modified resins are resins prepared using rosin as one of the raw materials. Rosin contains a mixture of resin acids such as abietic acid, palustric acid, isopimaric acid, and levopimaric acid, and these resin acids contain hydrophilic and chemically active carboxyl groups, some of which have conjugated double bonds. For this reason, various rosin-modified resins are prepared by combining polyhydric alcohols and polybasic acids and polycondensing them, adding resol, which is a condensate of phenol, to the benzene ring contained in the rosin skeleton, or by carrying out a Diels-Alder reaction with maleic anhydride or maleic acid, which is a dienophile, to add maleic acid or maleic anhydride skeletons. Various types of such rosin-modified resins are commercially available, and it is also possible to obtain and use them.

[0048] Examples of rosin-modified resins include maleated rosin, fumarated rosin, rosin-modified maleic acid resin, rosin-modified fumaric acid resin, rosin-modified phenolic resin, rosin-modified alkyd resin, and rosin-modified polyester resin. Any rosin-modified resin may be used in the present invention, but among these, those containing in their structure a moiety derived from at least one selected from the group consisting of maleic acid, maleic anhydride, fumaric acid, and fumaric anhydride are preferably used. A resin "containing in its structure a moiety derived from at least one selected from the group consisting of maleic acid, maleic anhydride, fumaric acid, and fumaric anhydride" is one prepared using at least one selected from the group consisting of maleic acid, maleic anhydride, fumaric acid, and fumaric anhydride as part of a raw material, and means, for example, a rosin-modified maleic acid resin or rosin-modified fumaric acid resin obtained by condensation polymerization of maleic acid or fumaric acid as part of a polybasic acid, a maleated rosin or fumarated rosin having a structure in which maleic acid, maleic anhydride, fumaric acid, or fumaric anhydride is added as a dienophile by a Diels-Alder reaction, or a resin obtained by further polymerizing other chemical species using the functional groups contained in these.

[0049] The acid value of the rosin-modified resin is preferably from 10 to 400 mgKOH / g, and more preferably from 100 to 300 mgKOH / g.

[0050] (Other ingredients) The primer layer may contain a resin other than the water-soluble resin or the compound having an acidic group. Examples of such resins include cellulose resins, polyamide resins, vinyl chloride resins such as vinyl chloride-vinyl acetate copolymer resins or vinyl chloride-acrylic copolymer resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, acrylic resins, styrene resins, dammar resins, styrene-acrylic copolymer resins, polyester resins, alkyd resins, terpene resins, phenol-modified terpene resins, ketone resins, cyclized rubbers, chlorinated rubbers, butyral, polyacetal resins, petroleum resins, and modified resins thereof. These resins may be used alone or in combination of two or more. Among them, the primer layer preferably contains at least one resin selected from the group consisting of cellulose resin, vinyl chloride resin, rosin resin, and acrylic resin, and more preferably contains vinyl chloride resin or acrylic resin. The mass ratio of the urethane resin having an acidic group to the other resin (urethane resin having an acidic group:other resin) is preferably 95:5 to 50:50. When the mass ratio is within the above range, the ink layer is peeled off in a thin film state when the ink layer is peeled off together with the primer layer in a basic aqueous solution, which is preferable because it makes recovery easy.

[0051] The primer layer may contain a body pigment. Examples of the body pigment include silica, barium sulfate, kaolin, clay, calcium carbonate, magnesium carbonate, zinc oxide, zirconium oxide, and other metal oxides. Among these, silica is preferred, and hydrophilic silica is more preferred. The average particle size of the extender pigment is preferably 0.5 to 10 μm, more preferably 1 to 8 μm. The content of the extender pigment in the primer layer is preferably 0.5 to 10 mass %, more preferably 1 to 5 mass %. When the average particle size and the content of the extender pigment are within the above ranges, the wettability of the ink layer is improved, and image quality is improved.

[0052] The primer layer may be a layer in which the above-mentioned urethane resin having an acidic group is crosslinked with a curing agent. By introducing a crosslinked structure into the primer layer, the penetration and bleeding of the ink layer formed on the primer layer is suppressed, and excellent image quality can be achieved. The curing agent may be, for example, a polyisocyanate. The polyisocyanate is not particularly limited and may be selected from conventionally known polyisocyanates, for example, an aliphatic polyisocyanate or an aromatic aliphatic polyisocyanate. These may be used alone or in combination of two or more kinds.

[0053] The primer layer may further contain known additives, such as dispersants, wetting agents, adhesion promoters, leveling agents, defoamers, antistatic agents, viscosity modifiers, metal chelates, trapping agents, antiblocking agents, wax components other than those mentioned above, and silane coupling agents.

[0054] The thickness of the primer layer is preferably in the range of 0.5 to 3.0 μm, more preferably 0.6 to 2.0 μm, and further preferably 0.8 to 1.5 μm, and can be formed by using a known method.

[0055] [Detached ink layer] The ink layer is a layer on which any printed pattern is formed for the purpose of decoration, imparting aesthetic appeal, displaying the contents, expiration date, manufacturer or seller, etc., and includes a solid printed layer. When the release layer is an ink layer, the ink layer is disposed in contact with the resin substrate and plays a role in releasing the resin substrate by dissolving or peeling with a release liquid. The ink layer preferably contains a water-soluble resin or a compound having an acidic group, and a colorant. The method for forming the ink layer is not limited, and the ink layer can be formed by a known method. From the viewpoint of recoatability, the ink layer preferably contains a compound containing an acidic group. Also, from the viewpoint of printability, the ink layer preferably contains a urethane resin having an acidic group, an acrylic resin having an acidic group, or a rosin-modified resin. For the above-mentioned water-soluble resin and compound having an acidic group, as well as the urethane resin having an acidic group, the acrylic resin having an acidic group, and the rosin-modified resin, the descriptions of (water-soluble resin), (compound having an acidic group), [urethane resin having an acidic group], [acrylic resin having an acidic group], and [rosin-modified resin] in the section [Desorption primer layer] described above can be used.

[0056] (Coloring agent) The ink layer may be colored or colorless and contains a known colorant used in printing inks and paints. Such colorants are not particularly limited, and may include inorganic pigments, organic pigments, dyes, metal powders that impart metallic luster, near-infrared absorbing materials, and ultraviolet absorbing materials. Examples of inorganic pigments include color pigments such as titanium oxide, red iron oxide, Prussian blue, ultramarine blue, carbon black, and graphite; and extender pigments such as calcium carbonate, kaolin, clay, barium sulfate, aluminum hydroxide, and talc. As the organic pigment, a soluble azo pigment, an insoluble azo pigment, an azo lake pigment, a condensed azo pigment, a copper phthalocyanine pigment, a condensed polycyclic pigment, etc. are suitably used. However, the pigment is not limited to these, and any pigment listed by its generic name in the Color Index can be used as appropriate. Among them, when the release solution is a basic aqueous solution, a pigment that is not eluted in the basic aqueous solution and has alkali resistance is preferred. Preventing the elution of the pigment makes it easy to reuse the basic aqueous solution. The alkali resistance of a pigment is generally estimated based on the skeleton or structure of the pigment. Examples of alkali-resistant pigments include inorganic pigments, CI Pigment Blue 15, and CI Pigment Yellow 83. When the pigment is titanium oxide, the content of titanium oxide in the ink layer is preferably 20 to 80% by mass, more preferably 30 to 75% by mass. When the pigment is an inorganic pigment other than titanium oxide, an extender pigment, or an organic pigment, the content of each of these pigments in the ink layer is preferably 0.5 to 60% by mass, more preferably 10 to 50% by mass.

[0057] (Other ingredients) The ink layer may contain a pigment derivative or a resin-type dispersant as a dispersant for the colorant. The pigment derivative is a compound in which a substituent has been introduced into the skeleton of a pigment, and the content of the pigment derivative is preferably 0.01 to 10 mass%, more preferably 0.05 to 6 mass%, and even more preferably 0.1 to 4 mass%, based on the mass of the colorant. When it is 0.01 mass% or more, it is excellent in releasability from the resin substrate, and when it is 10 mass% or less, it is possible to suppress reattachment of the ink layer. The resin-type dispersant functions to adsorb to the colorant and stabilize the dispersion in the printing ink, etc., and can be appropriately selected from known resin-type dispersants. The content of the resin-type dispersant is preferably 0.01 to 30% by mass, more preferably 0.05 to 20% by mass, and even more preferably 0.1 to 10% by mass, based on the mass of the colorant. When it is 0.01% by mass or more, the releasability of the resin substrate is excellent, and when it is 30% by mass or less, the ink layer is excellent in water resistance.

[0058] The ink layer may contain a resin other than the water-soluble resin or the compound containing an acidic group. Examples of such resins include fibrous materials such as nitrocellulose and cellulose acetate propionate, chlorinated polypropylene, vinyl chloride-vinyl acetate copolymer, polyester, acrylic, urethane resin and acrylic urethane, polyamide, polybutyral, cyclized rubber, and chlorinated rubber. These resins may be used alone or in combination of two or more.

[0059] The thickness of the ink layer is preferably from 0.1 μm to 100 μm, more preferably from 0.1 μm to 10 μm, and further preferably from 1 μm to 5 μm.

[0060] [Removable adhesive layer] When the release layer is an adhesive layer, the adhesive layer is disposed in contact with the resin substrate and plays a role in releasing the resin substrate by dissolution, peeling, etc., using a release liquid. The adhesive layer preferably contains a compound having an acidic group. When the adhesive layer contains a resin having an acidic group or a low molecular weight compound having an acidic group, the adhesive layer can be released using the above-mentioned basic aqueous solution. The above-mentioned compound having an acidic group, resin having an acidic group, and low molecular weight compound having an acidic group can be described in the above [Removal primer layer] section (Compound having an acidic group). do. The method for forming the adhesive layer is not limited, and the adhesive layer can be formed by using a known method.

[0061] From the viewpoint of releasability, the adhesive layer may be a cured product of an adhesive containing a polyester polyol having an acidic group and at least one polyisocyanate selected from the group consisting of an aliphatic polyisocyanate and an araliphatic polyisocyanate. The cured product corresponds to a resin having an acidic group. The adhesive layer may also be a cured product of an adhesive containing a polyester polyol, at least one polyisocyanate selected from the group consisting of aliphatic polyisocyanates and araliphatic polyisocyanates, and a low molecular weight compound having an acidic group.

[0062] (Polyester polyol) The polyester polyol may have an acidic group and may be appropriately selected from known polyester polyols. By including such a polyester polyol, when a basic aqueous solution is used as the release liquid, the release property is improved by having an ester bond with high affinity with a basic compound, which is preferable. The polyester polyol may be used alone or in combination of two or more kinds.

[0063] The polyester polyol is not particularly limited, but polyester polyols obtained by reacting a carboxyl group component (also called a polyvalent carboxylic acid) with a hydroxyl group component (also called a polyhydric alcohol); or polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, polyvalerolactone, and poly(β-methyl-γ-valerolactone) are preferably used. Examples of the carboxyl group component include dibasic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, phthalic anhydride, adipic acid, azelaic acid, sebacic acid, succinic acid, glutaric acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, and itaconic anhydride, or dialkyl esters thereof, or mixtures thereof. Examples of the hydroxyl group component include diols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, butylene glycol, neopentyl glycol, trimethylolpropane, glycerin, 1,6-hexanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 3,3'-dimethylolheptane, 1,9-nonanediol, polyoxyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, polyether polyol, polycarbonate polyol, polyolefin polyol, acrylic polyol, polyurethane polyol, and mixtures thereof. The above carboxyl group components and hydroxyl group components may be used in combination of two or more kinds.

[0064] The polyester polyol may be a polyester urethane polyol obtained by reacting a hydroxyl group in a polyol with a polyisocyanate. The polyester polyol has a urethane bond, and thus exhibits excellent heat resistance and adhesiveness. Examples of the polyisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, and hydrogenated diphenylmethane diisocyanate.

[0065] The polyester polyol may be an acid anhydride-modified product obtained by reacting an acid anhydride with a hydroxyl group in the polyol, thereby introducing a carboxyl group, which is an acidic group, into the polyester polyol. Examples of the acid anhydride include pyromellitic anhydride, mellitic anhydride, trimellitic anhydride, and trimellitic ester anhydride. Examples of the trimellitic ester anhydride include ethylene glycol bisanhydrotrimellitate and propylene glycol bisanhydrotrimellitate.

[0066] The acid value of the polyester polyol is preferably 5.0 mgKOH / g or more, more preferably 10.0 mgKOH / g or more. The acid value of the polyester polyol is preferably 100 mgKOH / g or less, more preferably 80 mgKOH / g or less. When the acid value of the polyester polyol is in the above range, when the polyester polyol is contacted with a release liquid that is a basic aqueous solution, the basic aqueous solution penetrates and decomposes the polyester polyol, thereby exhibiting better release properties. When the adhesive contains a plurality of polyester polyols, the acid value of the entire polyester polyols can be determined from the acid value of each polyester polyol and its mass ratio.

[0067] The number average molecular weight (Mn) of the polyester polyol is preferably 3,000 to 25,000, more preferably 5,000 to 20,000, and particularly preferably 7,000 to 15,000. When the number average molecular weight of the polyester polyol is 3,000 or more, not only the coatability but also sufficient retort suitability can be exhibited, and when it is 20,000 or less, not only the coatability but also the release property is improved, so this is preferable.

[0068] In order to satisfy various physical properties required for the packaging material, the polyester polyol component may contain a combination of multiple polyester polyol components, for example, a polyester polyol having a number average molecular weight of 5,000 to 20,000, and further, in order to improve adhesion to the substrate, a polyester polyol having a number average molecular weight of less than 3,000 may be contained. The content of the polyester polyol having a number average molecular weight of less than 3,000 is preferably 0 to 30 mass %, more preferably 0 to 20 mass %, based on the total mass of the polyester polyol. When it is 30 mass % or less, retort resistance can be maintained.

[0069] (Other polyols) The adhesive constituting the adhesive layer may contain a polyol other than the polyester polyol. The polyol that may be contained other than the polyester polyol is not particularly limited, and examples thereof include polycarbonate polyol, polycaprolactone polyol, polyether polyol, polyolefin polyol, acrylic polyol, silicone polyol, castor oil-based polyol, and fluorine-based polyol.

[0070] (Polyisocyanate) The polyisocyanate to be combined with the above-mentioned polyester polyol to form the adhesive layer is preferably at least one selected from the group consisting of known aliphatic polyisocyanates and araliphatic polyisocyanates.

[0071] Examples of the aliphatic polyisocyanate include acyclic aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, and 1,2-butylene diisocyanate; alicyclic diisocyanates such as 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, and 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (hereinafter, referred to as isophorone diisocyanate); and polyisocyanates such as allophanate type, nurate type, biuret type, and adduct type derivatives derived from the above diisocyanates, or complexes thereof. The derivative is preferably a nurate type or an adduct type, more preferably an adduct type. The aliphatic polyisocyanate is derived from hexamethylene diisocyanate (hereinafter also referred to as HDI), which is easy to balance between releasability and laminate properties. Derived polyisocyanates are preferred.

[0072] Examples of the araliphatic polyisocyanate include araliphatic diisocyanates such as 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, ω,ω'-diisocyanato-1,4-diethylbenzene, 1,3- or 1,4-bis(1-isocyanato-1-methylethyl)benzene or a mixture thereof; and polyisocyanates such as allophanate type, nurate type, biuret type, and adduct type derivatives derived from the above araliphatic diisocyanates, or complexes thereof.

[0073] (Other polyisocyanates) The adhesive may contain polyisocyanates other than the aliphatic polyisocyanates and aromatic aliphatic polyisocyanates, as long as the effects of the present invention are not impaired. Examples of such polyisocyanates include aromatic diisocyanates such as toluene diisocyanate and diphenylmethane diisocyanate; and polyisocyanates such as derivatives of the above diisocyanates or complexes thereof.

[0074] The polyol and polyisocyanate may be mixed so that the molar ratio (NCO / OH) of the isocyanate groups of the polyisocyanate to the hydroxyl groups of the polyol is 0.3 to 10.0, preferably 0.3 to 7.0, and more preferably 0.5 to 5.0.

[0075] (Other ingredients) The adhesive layer may contain, in addition to a silane coupling agent, a phosphorus oxygen acid or a derivative thereof, a leveling agent, an antifoaming agent, and a reaction accelerator, inorganic fillers (e.g., silica, alumina, mica, talc, aluminum flakes, glass flakes), layered inorganic compounds, stabilizers (e.g., antioxidants, heat stabilizers, UV absorbers, hydrolysis inhibitors), rust inhibitors, thickeners, plasticizers, antistatic agents, lubricants, antiblocking agents, colorants, fillers, crystal nucleating agents, catalysts for adjusting the curing reaction, and the like.

[0076] The thickness of the adhesive layer is preferably in the range of 1 to 10 μm, and more preferably 1 to 6 μm.

[0077] [Metal deposition layer, inorganic oxide deposition layer] Vapor-deposited layers of metals such as aluminum and vapor-deposited layers of inorganic oxides such as alumina and silica dissolve in a basic aqueous solution and are released, so they function as release layers and can separate adjacent resin substrates. The thickness of the metal vapor deposition layer and the inorganic oxide vapor deposition layer is not particularly limited, but is preferably 0.001 to 5 μm.

[0078] <Resin base layer> The resin substrate constituting the resin substrate layer is not particularly limited, but is preferably a sheet-shaped resin substrate, for example, a conventionally known plastic film.The resin substrate layer may be a single-layer structure made of one resin substrate, or a multi-layer structure made of multiple resin substrates.In addition, when the resin substrate layer is a structure in which two resin substrates are laminated via an adhesive layer, the two resin substrates may be the same type or different types.

[0079] The plastic film may be a film of a thermoplastic resin or a thermosetting resin, and is preferably a film of a thermoplastic resin. Examples of the thermoplastic resin include polyolefin resin, polyester resin, polyamide resin, polystyrene resin, vinyl chloride resin, vinyl acetate resin, ABS resin, acrylic resin, acetal resin, polycarbonate resin, etc. Examples of plastics include cellulose resins and cellulose-based plastics. The resin substrate may have, as a release layer, the vapor deposition layer (barrier layer) described above in the section [Metal vapor deposition layer] or [Inorganic oxide vapor deposition layer].

[0080] Specific examples of plastic films include polyester resin films such as polyethylene terephthalate, polyethylene naphthalate (PEN), and polylactic acid (PLA); polyolefin resin films such as polyethylene (PE) and polypropylene (PP); polystyrene resin films; polyamide resin films such as nylon 6 and poly-p-xylylene adipamide (MXD6 nylon); polycarbonate resin films; polyacrylonitrile resin films; polyimide resin films; laminates thereof (e.g., nylon 6 / MXD6 / nylon 6, nylon 6 / ethylene-vinyl alcohol copolymer / nylon 6) and mixtures thereof. Among these, those having mechanical strength and dimensional stability are preferred. The thickness of the plastic film is not particularly limited, but is preferably 5 to 100 μm, and more preferably 10 to 50 μm.

[0081] Furthermore, a sealant substrate can be used as the plastic film. Examples of sealant base materials include polyethylenes such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE), acid-modified polyethylene, polypropylene (PP), acid-modified polypropylene, copolymerized polypropylene, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid ester copolymer, ethylene-(meth)acrylic acid copolymer, and ionomer. The thickness of the sealant base material is not particularly limited, but is preferably 10 to 200 μm, more preferably 15 to 150 μm, in consideration of processability into packaging materials, heat sealability, etc. Furthermore, by providing the sealant base material with unevenness having a height difference of about several μm, it is possible to impart slipperiness and tearability to the packaging material.

[0082] It is important that the resin substrate constituting the resin substrate layer does not soften during shredding to block the cross section of the detachment layer. Therefore, the melting point of the resin substrate is preferably 90° C. or higher, more preferably 100° C. or higher, and even more preferably 120° C. or higher.

[0083] <Laminated film composition> The laminated film in the present invention is sufficient to have at least a resin substrate layer and a release layer, and may further have other layers within the scope of not impairing the effects of the present invention. Examples of layers that may be included include layers containing a resin that does not fall under the category of a release layer (e.g., an ink layer, an adhesive layer, a primer layer, an overcoat layer), metal foils such as aluminum foil, and paper such as natural paper and synthetic paper.

[0084] The laminated film may have, for example, the following configurations, and may have a configuration that satisfies two or more of the following configurations. (1) It has a partial structure having a resin substrate layer and an ink layer in this order, and the ink layer is a release layer. (2) It has a partial structure including a resin substrate layer, a primer layer, and an ink layer in this order, and the primer layer is a release layer. (3) It has a partial structure in which two resin substrate layers are laminated via an adhesive layer, and the adhesive layer is a release layer. A specific example of the above configuration is shown below. Resin substrate layer / detachable ink layer, Resin substrate layer / detachable primer layer / ink layer, Resin substrate layer / detachable ink layer / detachable adhesive layer / resin substrate layer, Resin substrate layer / detachable primer layer / ink layer / detachable adhesive layer / resin substrate layer, Resin substrate layer / ink layer / detachable adhesive layer / resin substrate layer, Resin substrate layer / detachable adhesive layer / resin substrate layer, Ink layer / resin substrate layer / detachable adhesive layer / resin substrate layer, Ink layer / resin substrate layer / adhesive layer / resin substrate layer / detachable adhesive layer / resin substrate layer, Detachable ink layer / resin substrate layer / detachable adhesive layer / resin substrate layer, Ink layer / detachable primer layer / resin substrate layer / detachable adhesive layer / resin substrate layer, Resin substrate layer / detachable primer layer / ink layer / detachable adhesive layer / inorganic oxide vapor deposition layer (detachable layer) / resin substrate layer, Resin substrate layer / detachable primer layer / ink layer / adhesive layer / inorganic oxide vapor deposition layer (detachable layer) / resin substrate layer / detachable adhesive layer / resin substrate layer.

[0085] <Method of separating and recovering laminated film> The separation and recovery method of the present invention includes the following steps. (1) A shredding process in which the laminated film is shredded while being cooled with water whose liquid temperature is set to 50° C. or less using a cooling means to obtain shredded material. (2) A separation step in which the shredded material is immersed in a release liquid to separate the resin substrate layer. (3) A recovery step of recovering the separated resin substrate layer

[0086] [Process (1)] Shredding process In step (1), the laminated film is shredded to obtain shredded material, and it is important to shred the film while cooling it with water whose liquid temperature is kept at 50°C or less using a cooling means. By shredding the film while cooling it with water at 50°C or less, it is possible to prevent the resin substrate from melting due to the heat generated when shredding a large amount of film with the shredding device, and to prevent the cross section of the detachment layer from being blocked. This ensures that the cross section of the detachment layer is not hindered from being exposed, and does not reduce the releasability. Furthermore, by using a cooling means, the temperature of the water can be kept below 50°C at all times, which prevents the cross section of the detachment layer from being blocked throughout the entire shredding process. If a cooling means is not used, the liquid temperature will rise due to the heat generated during shredding, making it difficult to achieve a cooling effect. The temperature of the water is preferably low from the viewpoint of preventing softening and fusion during shredding, and is preferably 39° C. or less, more preferably 29° C. or less, and further preferably 20° C. or less. When the temperature is within the above range, the temperature rise due to shear during shredding is suppressed, the resin substrate of the laminated film is less likely to melt or soften, and the cross section of the release layer is more likely to be exposed, which is preferable.

[0087] The cooling means for keeping the water temperature at 50° C. or less is not particularly limited, and examples thereof include, but are not limited to, a method in which new water at 50° C. or less is added to the shredding section as needed, a method in which, when water is recycled, warm water is cooled to 50° C. or less using a cooling device and then added to the shredding section as needed, and a method in which a cooling device is provided in the shredding device to keep the liquid temperature at 50° C. or less. The type of cooling device is not limited, and can be any known type such as an air-cooling type or a liquid-cooling type.

[0088] An example of the shredding method is a method using a cutter mill (rotary cutter), and examples of shredding devices using a cutter mill include MF45-700WRS manufactured by Tanaka and PF-2000 model manufactured by Nippon Seam.

[0089] An example of the shredding process in the present invention is shown below. Water at 50°C or less is continuously fed from the water inlet of the shredding device. By continuously feeding the water, it is possible to perform shredding using water at a temperature of 50°C or less. The water fed from the water inlet may be fed using a spray nozzle or the like to efficiently wet and cool the shredded material in the device. On the other hand, the laminated film is fed from the laminated film feed port, and is chopped into pieces of a predetermined size or less in the chopping section together with water fed from the water inlet. The chopping section is of a known structure. In the chopping section, it is preferable to use a rotary cutter that chops the material using shear force.

[0090] In the shredding process, the water may contain a detergent or the like in order to clean dirt such as contents adhering to the laminated film. The water used in the shredding process may also contain a component of the release liquid. When the water used in the shredding process contains a detergent or a component of the release liquid, separation in the separation process can be promoted. However, the present invention is characterized in that the shredding process and the separation process are carried out separately in order to prevent impurities such as ink flakes from adhering to and accumulating on the resin substrate, and the components of the cleaning agent and release liquid that may be contained in the water used in the shredding process must be within a range that does not cause separation of the resin substrate layer.

[0091] As shredding progresses and the size of the shredded material falls below a certain level, it passes through a screen installed at the bottom of the shredding section under its own weight together with the water. A screen is a device that acts as a filter to allow materials below a certain size to pass through, and is sometimes called a filter or grid. The shape of the screen can be circular, diamond, fan-shaped, etc., and can be selected appropriately depending on the hardness and thickness of the shredded material. The long side of the shredded material can be adjusted depending on the size of the screen used. For example, if the screen is circular, by using a screen with a diameter of 15 mm, the length of the longest side of the shredded material (long side) can be controlled to 15 mm. The long side of the shredded material is preferably 5 to 50 mm, more preferably 5 to 40 mm, and even more preferably 10 to 30 mm. When the long side is within the above range, the time required for the eluent to permeate from the end face of the shredded material to the center is shortened in step (2) described below, and separation and recovery can be performed efficiently.

[0092] The mass of water used in the shredding step is preferably 2 to 500 times, more preferably 10 to 250 times, and further preferably 15 to 150 times the mass of the laminated film. Within the above range, the amount of water for cooling the laminated film is sufficient, and water is constantly flowing in and out of the shredded portion, suppressing local temperature increases in the shredded portion due to shearing, thereby suppressing fusion and softening of the resin substrate of the laminated film. In addition, by keeping the amount of water within the above range, not only the shredded material but also unnecessary components such as fine ink particles and adhesive particles generated during shredding can easily pass through the screen described above, preventing the laminated film from remaining in the shredding section and clogging of the screen with unnecessary components. This prevents the laminated film from remaining in excess in the shredding section, and suppresses the fusion of the resin substrate and the generation of fine particles due to excessive shredding. In addition, by suppressing clogging of the screen, shredded material of a constant size can be continuously produced. The mass of water used in the shredding process refers to the mass of water fed into the shredding device per minute, and the mass of laminated film refers to the mass of laminated film fed into the shredding device per minute.

[0093] In the separation and recovery method of the present invention, since the shredding step is carried out in a waste liquid, a selection step of selecting the laminate film of the present invention having at least the resin substrate layer and the release layer may be included prior to the shredding step. In addition, before the shredding step, a rough crushing step of shredding the laminated film into pieces of a size that can be easily fed into a shredding device may be included. Examples of the device used in the rough crushing step include a hydraulic cutter.

[0094] [Step (4)] Washing and filtration step The separation and recovery method of the present invention may include the following step (4) between step (1) and step (2) described below. (4) A washing and filtering step in which the shredded material is washed with water to remove fine particles. The laminated film that passes through the screen contains unnecessary components that degrade the quality of the recycled resin substrate after recovery, such as food residues and tiny ink and adhesive particles that are generated during shredding, so it is preferable to wash the shredded material with water and perform washing and filtration to remove the tiny particles. The washing and filtration process removes most of the dirt, such as attached food residues and tiny particles (ink particles, adhesive particles, etc.). It is preferable to use a continuous processing method for the series of steps from shredding to drying and transport, since it is more efficient to proceed with the processing while continuously feeding water and laminated film from a water-cooled shredding device.

[0095] In the washing and filtering process, a known method such as water washing by showering can be used for washing. A known method for removing impurities together with the filtrate, such as a filter press, a filter screen, or a centrifugal dehydrator, can be used for filtering. In the filtering process, it is preferable to use a filter screen from the viewpoint of recovering shredded material of a certain size or more and removing other fine pieces. The filtration screen may be called a filter or a grid. The shape of the screen may be, for example, a circle, a diamond, or a fan, and may be appropriately selected according to the shape of the object to be filtered. The shredded material is washed with water, and the shredded material is left behind using a filtration screen, while the fine pieces are passed through and removed, making it possible to separate and recover a higher quality film. Among them, the centrifugal washing and filtering mechanism, which washes and filters the material by centrifugal force while sending it to the discharge outlet, is suitable for step (4). In a centrifugal washing filter, a cylindrical filter screen is fixed to the inner surface of a cylindrical outer cylinder in a double cylindrical shape. A rotating rotor having a rotating shaft coaxial with the central axis of the washing filter device is provided inside the filter screen. In addition, a scraper blade is attached to the rotating rotor, which transports the shredded material to the discharge outlet while rotating. With these mechanisms, the water containing the shredded material and fine pieces that have passed through the above step (1) is sent to the discharge outlet in the washing filter device, and only shredded material larger than the size of the filter screen is sent, and the water and fine pieces are continuously discharged outside the filter screen. The shape and size of the filter screen are preferably adjusted so that as much of the shredded material to be collected as possible remains within the screen, and fine particles, which are unnecessary components, can be discharged outside the screen. When the screen is circular in shape, its diameter is preferably 0.1 mm to 45 mm, more preferably 0.5 mm to 30 mm, and even more preferably 0.5 mm to 15 mm. The water and fine particles discharged outside the filter screen are discharged from a drain. The shape of the fine particles is not particularly limited, but the length or diameter thereof is preferably 10 mm or less.

[0096] The shape of the washing and filtering apparatus may be either vertical or horizontal, and is appropriately selected based on the size of the apparatus and ease of connection to other apparatuses. The water used in the above steps (1) and (4) may be reused after undergoing a process for removing impurities.

[0097] The shredding, washing and filtering device is not particularly limited, but for example, devices manufactured by Tanaka or Nippon Seam can be used.

[0098] [Step (2)] Separation step Step (2) is a step of immersing the obtained shredded material in a release liquid to separate the resin substrate layer, and the method can be appropriately selected from known methods.

[0099] (Removal solution) The release liquid may be any liquid capable of swelling and dissolving the release layer to thereby peel off the resin substrate, and may be appropriately selected in consideration of the ease of detachment of the release layer. Examples of the solvent include water, a basic aqueous solution, an acidic aqueous solution, and a fluorine-based solvent. From the viewpoint of the environment and maintaining the properties of the recycled material using the recovered resin substrate, water or an aqueous solution is preferable. In addition, a basic aqueous solution containing a basic compound is more preferable because it is possible to remove both the layer containing a compound having an acidic group and the layer containing a water-soluble resin. These removal liquids may be heated.

[0100] [Basic Compounds] The basic compound is not particularly limited, and for example, sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), ammonia, barium hydroxide (Ba(OH)2), and sodium carbonate (Na2CO3) are preferably used. More preferably, it is at least one selected from the group consisting of sodium hydroxide and potassium hydroxide. The content of the basic compound in the basic aqueous solution is preferably 0.5 to 20% by mass, more preferably 1 to 15% by mass, and even more preferably 3 to 15% by mass, based on the mass of the basic aqueous solution. Within the above range, the basic aqueous solution can retain sufficient basicity to dissolve or swell the detachment layer and detach it to recover the resin substrate layer.

[0101] As described above, the release liquid penetrates the end surface of the shredded material, comes into contact with the release layer, and dissolves or swells, separating the resin substrate layer from the release layer. The shredded material obtained in step (1) is shredded while being cooled with water whose liquid temperature is set to 50°C or less using a cooling means, so that fusion and softening of the resin substrate layer is suppressed and the cross section of the release layer is exposed. Therefore, the release liquid penetrates the release layer in a shorter time, and the resin substrate layer can be efficiently released.

[0102] The temperature of the release liquid when the shredded material is immersed is preferably in the range of 25 to 120°C, more preferably 30 to 120°C, and particularly preferably 30 to 80°C. The immersion time in the release liquid is preferably in the range of 1 minute to 24 hours, more preferably 1 minute to 12 hours, and preferably 1 minute to 6 hours. The amount of the release liquid used is preferably in the range of 50,000 to 100,000 times, more preferably 10 to 10,000 times, the mass of the shredded material, and it is preferable to stir or circulate the release liquid in order to improve the release efficiency. The rotation speed is preferably 80 to 5000 rpm, more preferably 80 to 4000 rpm.

[0103] As the desorption liquid, the water used in the step (1) or (4) may be reused after removing impurities.

[0104] [Process (3)] Recovery process Step (3) is a step of recovering the resin substrate layer separated in step (2), and can be appropriately selected from known recovery methods. Examples of the recovery method include a method using filter filtration. The method includes any separation means including a filter, such as a cartridge filter, a belt filter, a drum filter, a dyna filter, a rotary filter, a mesh, a screen, a drum screen, a slurry cleaner, an autostrainer, an extrusion type centrifuge, a continuous centrifuge, and a filtration system, and a mesh conveyor that can convey while filtering with a filter may be used.

[0105] In step (3), a step of removing components other than the resin substrate layer, such as the ink and adhesive, separated from the laminated film, may be provided before recovering the resin substrate layer. The ink, adhesive, and other components are finely divided by the shear force in step (2), and by adjusting the size of the filter based on the difference in size between the shredded material in step (1), the resin substrate layer can be recovered while removing fine pieces of the ink and adhesive components adhering to the resin substrate component. The release liquid remaining after the resin substrate layer is recovered and components other than the resin substrate layer, such as ink and adhesive, are removed may be reused in step (2).

[0106] Step (3) may include a step of selecting the resin type of the resin substrate layer (selection step). Examples of the selection step include a gravity selection method using a liquid, a wind selection method, and a near-infrared selection method. From the viewpoint of productivity, the gravity selection method using a liquid is preferred. In the gravity separation method using a liquid, for example, when water is used as the density liquid, it is possible to separate resin substrates having a lower density than water, such as polyethylene and polypropylene, from resin substrates having a higher density than water, such as polyester, nylon and cellophane. The density liquid may be appropriately adjusted by blending an organic solvent, an aqueous solution of a metal salt compound, or the like, either alone or in combination. Such density separation may be performed multiple times. The recovered resin substrate layer is reused after being subjected to treatments such as dehydration and drying, if necessary.

[0107] <Reuse of resin substrate layer> The resin substrate layer recovered by the above-mentioned separation and recovery method can be melt-kneaded to produce a molding material. The melt kneading process refers to adding various additives as necessary, mixing with a Henschel mixer, tumbler, disperser, etc., and then mixing and dispersing using a batch type kneader such as a kneader, roll mill, super mixer, Henschel mixer, Shugi mixer, vertical granulator, high speed mixer, Farmatrix, ball mill, steel mill, sand mill, vibration mill, attritor, Banbury mixer, twin screw extruder, single screw extruder, rotor type twin screw kneader, etc. This results in a recycled resin, which is a resin composition. The shape of the recycled resin is not particularly limited and may be pellet-shaped, powder-shaped, granular, or bead-shaped. The melt kneading process is preferably performed using a twin screw extruder.

[0108] The molding material may further contain a masterbatch. The masterbatch is not particularly limited as long as it is compatible with the recycled resin, and generally, a mixture of a thermoplastic resin such as a polyethylene resin or a polypropylene resin and a colorant can be used. The thermoplastic resin contained in the masterbatch may be used alone or in combination of two or more kinds. The master batch may contain, within the scope not impairing the effects of the present invention, a metallic soap of an alkali metal, an alkaline earth metal, or zinc, hydrotalcite, a nonionic surfactant, a cationic surfactant, an anionic surfactant, an amphoteric surfactant, an antistatic agent, a flame retardant such as a halogen-based, phosphorus-based, or metal oxide, a lubricant such as ethylene bis alkyl amide, an antioxidant, an ultraviolet absorber, or a filler.

[0109] The molding material obtained as described above can be heated and molded to obtain a molded article. The heating and molding method is not particularly limited, and examples thereof include injection molding, extrusion molding, blow molding, and compression molding. Molding materials produced using the resin substrate layer recovered by the separation and recovery method of the present invention have excellent releasability because the cross sections of the shredded material are not blocked, and therefore have reduced amounts of adhering components and are of high quality, and can be used in a variety of fields, including home appliances, stationery, automobile parts, toys, sporting goods, medical materials, and building and construction materials. EXAMPLES

[0110] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the present invention, "parts" and "%" represent "parts by mass" and "% by mass" unless otherwise noted.

[0111] <Molecular weight and molecular weight distribution> The weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) are The molecular weight was determined by gel permeation chromatography (PC) using polystyrene as a standard substance under the following measurement conditions: GPC equipment: Showa Denko Shodex GPC-104 Columns: The following columns were used in series connection: Showa Denko Shodex LF-404 x 2 Showa Denko Shodex LF-G Detector: RI (differential refractometer) Measurement conditions: Column temperature 40℃ Eluent: Tetrahydrofuran Flow rate: 0.3mL / min

[0112] <Acid value, hydroxyl value> The acid value and hydroxyl value were measured in accordance with JIS K 0070 (1992).

[0113] <Production of primer resin> [Synthesis Example 1-1] (Polyurethane Resin P1) In a reactor equipped with a reflux condenser, a dropping funnel, a gas inlet tube, a stirrer, and a thermometer, 101.2 parts of PPA (polyester polyol having Mn 2,000 made of a polycondensate of propylene glycol and adipic acid), 10.1 parts of PPG (polyether polyol having Mn 2,000 made of polypropylene glycol), 17.2 parts of DMPA (2,2-dimethylolpropanoic acid), 70.9 parts of IPDI (isophorone diisocyanate), and 140 parts of NPAC (normal propyl acetate) were charged while introducing nitrogen gas, and the mixture was reacted at 90°C for 5 hours to obtain a prepolymer solution having an isocyanate group at the end. Next, a mixture of 10.5 parts of AEA (2-(2-aminoethylamino)ethanol) and 245 parts of IPA (isopropyl alcohol) was added dropwise at room temperature over 60 minutes, and then reacted at 70°C for 3 hours to obtain a polyurethane resin solution. To the resulting polyurethane resin solution, 56 parts of NPAC and 49 parts of IPA were added to adjust the solid content, yielding a solution of polyurethane resin P1 with a solid content concentration of 30%, Mw of 24,000, Mw / Mn of 3.4 and an acid value of 34.5 mgKOH / g.

[0114] [Synthesis Example 1-2] (Polyurethane Resin P2) In a reactor equipped with a reflux condenser, a dropping funnel, a gas inlet tube, a stirrer, and a thermometer, 104.4 parts of PPA, 10.4 parts of PPG, 11.8 parts of BD (1,4-butanediol), 73.1 parts of IPDI, and 140 parts of NPAC were charged while introducing nitrogen gas, and the mixture was reacted at 90°C for 5 hours to obtain a urethane prepolymer solution having an isocyanate group at its end. Next, a mixture of 10.3 parts of AEA and 245 parts of IPA was added dropwise at room temperature over 60 minutes, and then the mixture was reacted at 70° C. for 3 hours to obtain a polyurethane resin solution. To the resulting polyurethane resin solution, 56 parts of NPAC and 49 parts of IPA were added to adjust the solid content, yielding a solution of polyurethane resin P2 with a solid content concentration of 30%, Mw of 23,000, Mw / Mn of 2.9 and an acid value of 0 mgKOH / g.

[0115] [Table 1]

[0116] The abbreviations in Table 1 are shown below. PPA: Polyester polyol with Mn of 2,000, made from the polycondensation of propylene glycol and adipic acid. PPG: Polyether polyol with Mn 2,000, made of polypropylene glycol DMPA: 2,2-dimethylolpropanoic acid BD: 1,4-butanediol IPDI: Isophorone diisocyanate NPAC: n-propyl acetate AEA: 2-(2-aminoethylamino)ethanol IPA: Isopropyl alcohol

[0117] <Composition for forming primer layer> [Production Example 1-1] (Primer composition S1) 87 parts of polyurethane resin P1 solution, 5 parts of EA, 5 parts of IPA, and 3 parts of silica particles (P-73 manufactured by Mizusawa Chemicals: hydrophilic silica particles having an average particle size of 3.8 μm) were mixed and stirred using a disper to obtain primer composition S1.

[0118] [Production Examples 1-2 to 1-3] (Primer Compositions S2 and S3) Primer compositions S2 and S3 were obtained in the same manner as in Production Example 1-1, except that the raw materials and compounding ratios were changed as shown in Table 2. [Table 2]

[0119] The abbreviations in Table 2 are shown below. Maleated rosin solution: A solution obtained by diluting Malkied No. 32 (acid value 135 mg KOH / g, solids concentration 100%) manufactured by Arakawa Chemical Industries, Ltd. with ethyl acetate to a solids concentration of 30%. PVA solution: A 15% aqueous solution of Kuraray Poval 5-88 (degree of saponification 86.5-89.0%) manufactured by Kuraray. EA: Ethyl acetate

[0120] <Ink layer forming composition> [Printing ink I1] 95 parts of Rio Alpha R39 Indigo (manufactured by Toyo Ink Co., Ltd.) and 5 parts of maleic rosin solution were mixed and stirred using a disper to obtain a printing ink composition I1. For the maleic rosin solution, a solution of Arakawa Chemical Industries' Malkied No. 32 (acid value 135 mg KOH / g, solid content concentration 100%) diluted with ethyl acetate to a solid content concentration of 30% was used.

[0121] [Printing ink I2] Rio Alpha R39 indigo (manufactured by Toyo Ink Co., Ltd.) was used as printing ink I2.

[0122] <Production of polyols used in adhesives> [Synthesis Example 2-1] (Polyester polyol A1) In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank and a nitrogen gas inlet tube, 204 parts of ethylene glycol, 215 parts of neopentyl glycol, 210 parts of 1,6-hexanediol, 579 parts of isophthalic acid, 61 parts of adipic acid and 232 parts of sebacic acid were charged, and the mixture was heated to 250°C while stirring under a nitrogen stream to carry out an esterification reaction. After a predetermined amount of water was distilled and the reaction was continued until the acid value was 5 or less, the pressure was gradually reduced and a deglycolization reaction was carried out at 1 mmHg or less for 5 hours to obtain a polyester polyol. Then, 34 parts of isophorone diisocyanate was gradually added, and the reaction was carried out at 150°C for about 2 hours to obtain a polyester polyurethane polyol. 13.0 parts of ethylene glycol bis-anhydrotrimellitate were added to 100 parts of this polyester polyurethane polyol and reacted at 180°C for approximately 2 hours. The mixture was then diluted with ethyl acetate until the non-volatile content reached 50%, yielding a solution of partially acid-modified polyester polyol A1 with Mn of 9,500 and an acid value of 31.5 mg KOH / g.

[0123] [Synthesis Example 2-2] (Polyester polyol A2) A reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank and a nitrogen gas inlet tube was charged with 242 parts of ethylene glycol, 401 parts of neopentyl glycol, 404 parts of isophthalic acid and 452 parts of adipic acid, and the mixture was heated to 250 ° C. while stirring under a nitrogen stream to carry out an esterification reaction. After a predetermined amount of water was distilled and the reaction was continued until the acid value was 5 or less, the pressure was gradually reduced and a deglycolization reaction was carried out at 1 mmHg or less for 5 hours to obtain a polyester polyol. 3.5 parts of trimellitic anhydride were added to 100 parts of this polyester polyol, and the mixture was reacted at 180 ° C. for about 2 hours, and then diluted with ethyl acetate until the non-volatile content was 50%, to obtain a solution of partially acid-modified polyester polyol A2 with Mn 2,000 and an acid value of 21.3 mg KOH / g.

[0124] [Synthesis Example 2-3] (Polyester polyol A3) In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank and a nitrogen gas inlet tube, 166 parts of ethylene glycol, 279 parts of neopentyl glycol, 158 parts of 1,6-hexanediol, 278 parts of terephthalic acid, 278 parts of isophthalic acid, 56 parts of adipic acid and 285 parts of sebacic acid were charged, and the temperature was raised to 250°C while stirring under a nitrogen stream to carry out an esterification reaction. After a predetermined amount of water was distilled and the reaction was continued until the acid value was 5 or less, the pressure was gradually reduced and a deglycolization reaction was carried out at 1 mmHg or less for 5 hours to obtain a polyester polyol. Then, 7.5 parts of isophorone diisocyanate was gradually added, and the reaction was carried out at 150°C for about 2 hours to obtain a polyester polyurethane polyol. 0.7 parts of trimellitic anhydride was added to 100 parts of this polyester polyurethane polyol and reacted at 180°C for approximately 2 hours. The mixture was then diluted with ethyl acetate until the solids concentration reached 50%, yielding a solution of partially acid-modified polyester polyol A3 with Mn of 7,500 and an acid value of 2.1 mgKOH / g.

[0125] <Production of high acid value resin> (High acid value resin H1) Malkied No. 32 (acid value 135 mg KOH / g, solid content concentration 100%) manufactured by Arakawa Chemical Industry Co., Ltd. was diluted with ethyl acetate to a solid content concentration of 30% to obtain a solution of high acid value resin H1.

[0126] (High acid value resin H2) 200 parts of toluene were charged into a reaction vessel equipped with a stirrer, a temperature system, a reflux condenser, a dropping tank, and a nitrogen gas inlet tube, and the temperature was raised to 110°C while introducing nitrogen gas and stirring. Next, 80 parts of methyl methacrylate, 50 parts of butyl acrylate, 100 parts of maleic anhydride, and 50 parts of toluene were charged into dropping tank 1, and a solution of 9 parts of benzoyl peroxide in 50 parts of toluene was charged into dropping tank 2, and each was simultaneously dropped over 2 hours with stirring while maintaining the temperature inside the reaction vessel at 110°C. After the reaction was completed, the mixture was cooled to room temperature, and the polymer was extracted with a large amount of methanol. The mixture was precipitated, filtered, and dried at 120°C for 6 hours to obtain a resin having a weight average molecular weight of 2,300 and an acid value of 465 mgKOH / g, which is a copolymer of (meth)acrylic acid ester and maleic anhydride. The resin was then diluted with ethyl acetate to a solid content concentration of 30%, to obtain a solution of high acid value resin H2.

[0127] <Adjustment of polyisocyanate> (Polyisocyanate C1) Coronate 2785 (biuret type polyisocyanate derived from hexamethylene diisocyanate, manufactured by Tosoh Corporation) was diluted with ethyl acetate to adjust the nonvolatile content to 50% and NCO% to 9.6%, to obtain a solution of polyisocyanate C1.

[0128] <Composition for forming adhesive layer> [Manufacturing Example 2-1] (Adhesive T1) 90 parts of the polyester polyol A1 solution, 10 parts of the polyester polyol A2 solution, and 8 parts of the polyisocyanate C1 solution were mixed, and ethyl acetate was added to obtain a solution of adhesive T1 with a solids concentration of 30%.

[0129] [Manufacturing Examples 2-2 to 2-4] (Adhesives T2 to T4) Except for changing the raw materials and blending compositions shown in Table 3, solutions of adhesives T2 to T4 were obtained in the same manner as in Production Example 2-1. [Table 3]

[0130] <Manufacturing of laminated film> The manufacturing method of the laminated film is explained below. Table 4 shows the composition of the laminated film and the types of primer, ink, and adhesive. The resin substrate layer to be recovered is underlined. In addition, the notation "-" in Table 4 indicates that the composition does not exist. The primer compositions (except primer composition S3) and printing inks were each diluted with a mixed solvent of EA / IPA (mass ratio 70 / 30) to a viscosity of 15 seconds (25°C, Zahn cup #3 (manufactured by Rigo Co., Ltd.) before use. The thicknesses of the primer layer and ink layer were each adjusted to about 1.5 μm. Primer composition S3 was adjusted to have the same viscosity and thickness, except that water was used as the dilution solvent.

[0131] [Manufacturing Example 3-1] (Laminated film L1) The diluted primer composition S1 and printing ink I2 were printed in that order over the entire surface of OPP (corona-treated stretched polypropylene film, thickness 20 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50°C to obtain a laminated film L1 having a composition of base layer (OPP) / detachable primer layer (S1) / ink layer (I2).

[0132] [Manufacturing Examples 3-2 and 3-3] (Laminated Films L2 and L3) Except for changing the substrate and primer composition to those shown in Table 4, the same procedure as in Production Example 3-1 was repeated to obtain laminate films L2 and L3.

[0133] [Manufacturing Example 3-4] (Laminated film L4) The diluted printing ink I1 was printed all over the OPP (thickness 20 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and dried at 50°C to obtain a laminated film L4 having a structure of base layer (OPP) / detached ink layer (I1).

[0134] [Manufacturing Example 3-5] (Laminated film L5) The diluted primer composition S1 and printing ink I2 were printed in that order over the entire surface of an OPP (thickness 20 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a structure of OPP / S1 / I2. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 2.5 g / m 2 After coating and drying so that the film became uniform, the film was laminated to a CPP (non-oriented polypropylene film, thickness 25 μm). The obtained laminated film was then kept at 40°C for 3 days to obtain a laminated film L5 having a structure of substrate layer (OPP) / detachable primer layer (S1) / ink layer (I2) / detachable adhesive layer (T1) / substrate layer (CPP).

[0135] [Manufacturing Examples 3-6 to 3-9] (Laminated Films L6 to 9) Except for changing the substrate, primer composition, and adhesive to those shown in Table 4, the same procedures as in Production Example 3-5 were carried out to obtain laminate films L6 to L9.

[0136] [Manufacturing Example 3-10] (Laminated film L10) The diluted printing ink I1 was printed over the entire surface of OPP (thickness 20 μm) in this order using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50°C to obtain a laminated film having a structure of OPP / I1. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 2.5 g / m 2 After coating and drying, the film was attached to a CPP (thickness: 25 μm). The resulting laminated film was then kept at 40° C. for 3 days to obtain a laminated film L10 having a structure of substrate layer (OPP) / detachable ink layer (I1) / detachable adhesive layer (T1) / substrate layer (CPP).

[0137] [Manufacturing Example 3-11] (Laminated film L11) The diluted primer composition S1 and printing ink I2 were printed in that order over the entire surface of an OPP (thickness 20 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a structure of OPP / S1 / I2. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 2.5 g / m 2 After coating and drying, the film was laminated to LLDPE (linear low density polyethylene film, thickness 30 μm). The obtained laminated film was then kept at 40°C for 3 days to obtain a laminated film L11 having a structure of substrate layer (OPP) / detachable primer layer (S1) / ink layer (I2) / detachable adhesive layer (T1) / substrate layer (LLDPE).

[0138] [Manufacturing Example 3-12] (Laminated film L12) A diluted primer composition S1 and a printing ink I2 were printed in that order over the entire surface of NY (nylon film, thickness 15 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a configuration of NY / S1 / I2. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After coating and drying, the laminate was laminated with LLDPE (thickness 80 μm). Next, the obtained laminated film was kept at 40°C for 3 days to obtain a structure of substrate layer (NY) / removable primer layer (S1) / ink layer (I2) / removable adhesive layer (T1) / substrate layer (LLDPE). Thus, a laminate film L12 having the above structure was obtained.

[0139] [Manufacturing Example 3-13] (Laminated film L13) A diluted primer composition S1 and a printing ink I2 were printed in that order over the entire surface of NY (thickness 25 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a configuration of NY / S1 / I2. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After coating and drying, the laminate was laminated to LLDPE (thickness 150 μm). The obtained laminated film was then kept at 40°C for 3 days to obtain a laminated film L13 having a structure of substrate layer (NY) / detachable primer layer (S1) / ink layer (I2) / detachable adhesive layer (T1) / substrate layer (LLDPE).

[0140] [Manufacturing Example 3-14] (Laminated film L14) The diluted printing ink I2 was printed over the entire surface of NY (thickness 25 μm) in this order using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a configuration of NY / I1. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After coating and drying, the laminate was laminated to LLDPE (thickness 150 μm). Next, the obtained laminated film was kept at 40° C. for 3 days to obtain a laminated film L14 having a structure of substrate layer (NY) / ink layer (I2) / detachable adhesive layer (T1) / substrate layer (LLDPE).

[0141] [Manufacturing Example 3-15] (Laminated film L15) The diluted primer composition S1 and the printing ink I2 were printed in that order over the entire surface of a PET (polyethylene terephthalate film, thickness 12 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a structure of PET / S1 / I2. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After coating and drying, the laminate was laminated with LLDPE (thickness 40 μm). The obtained laminated film was then kept at 40°C for 3 days to obtain a laminated film L15 having a structure of substrate layer (PET) / detachable primer layer (S1) / ink layer (I2) / detachable adhesive layer (T1) / substrate layer (LLDPE).

[0142] [Manufacturing Example 3-16] (Laminated film L16) A diluted primer composition S1 and a printing ink I2 were printed in that order over the entire surface of NY (thickness 15 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a configuration of NY / S1 / I2. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After coating and drying, the film was attached to a CPP (thickness 70 μm). The obtained laminated film was then kept at 40°C for 3 days to obtain a laminated film L16 having a structure of substrate layer (NY) / detachable primer layer (S1) / ink layer (I2) / detachable adhesive layer (T1) / substrate layer (CPP).

[0143] [Manufacturing Example 3-17] (Laminated film L17) The diluted primer composition S1 and the printing ink I2 were printed on the entire surface of a PET sheet (thickness 12 μm) in this order using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm. After drying at 0° C., a laminated film having a structure of PET / S1 / I2 was obtained. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After coating and drying, the film was laminated to NY (thickness 15 μm). Next, adhesive T1 was applied to the nylon film surface of the obtained laminated film in the same manner as above, with a coating amount of 3.0 g / m2 after drying. 2 After coating and drying, the film was attached to a CPP (thickness 70 μm). The obtained laminated film was then kept at 40°C for 3 days to obtain laminated film L17 having a structure of substrate layer (PET) / detachable primer layer (S1) / ink layer (I2) / detachable adhesive layer (T1) / substrate layer (NY) / detachable adhesive layer (T1) / substrate layer (CPP).

[0144] [Manufacturing Example 3-18] (Laminated film L18) The diluted primer composition S1 and printing ink I2 were printed in that order over the entire surface of PET (thickness 12 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a structure of PET / S1 / I2. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After coating and drying, the film was laminated to NY (thickness 15 μm). Next, adhesive T1 was applied to the nylon film surface of the obtained laminated film in the same manner as above, with a coating amount of 3.0 g / m2 after drying. 2 After coating and drying, the laminate was laminated with LLDPE (thickness 100 μm). Next, the obtained laminated film was kept at 40°C for 3 days to obtain a laminated film L18 having a structure of substrate layer (PET) / detachable primer layer (S1) / ink layer (I2) / detachable adhesive layer (T1) / substrate layer (NY) / detachable adhesive layer (T1) / substrate layer (LLDPE).

[0145] [Manufacturing Example 3-19] (Laminated film L19) The diluted primer composition S1 and printing ink I2 were printed in that order over the entire surface of PET (thickness 12 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a structure of PET / S1 / I2. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After coating and drying, the film was laminated to NY (thickness 15 μm). Next, adhesive T1 was applied to the nylon film surface of the obtained laminated film in the same manner as above, with a coating amount of 3.0 g / m2 after drying. 2 After coating and drying, the laminate was laminated to LLDPE (thickness 150 μm). Next, the obtained laminated film was kept at 40°C for 3 days to obtain a laminated film L19 having a structure of substrate layer (PET) / detachable primer layer (S1) / ink layer (I2) / detachable adhesive layer (T1) / substrate layer (NY) / detachable adhesive layer (T1) / substrate layer (LLDPE).

[0146] [Manufacturing Example 3-20] (Laminated film L20) The diluted primer composition S1 and printing ink I2 were printed in that order over the entire surface of a transparent silica-deposited PET (thickness 12 μm) surface using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50°C to obtain a laminated film having a structure of PET / silica-deposited layer / S1 / I2. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After coating and drying, the film was laminated to NY (thickness 15 μm). Next, adhesive T1 was applied to the nylon film surface of the obtained laminated film in the same manner as above, with a coating amount of 3.0 g / m2 after drying. 2 After coating and drying, the film was attached to a CPP (thickness 70 μm). The obtained laminated film was then kept at 40°C for 3 days to obtain a laminated film L20 having a structure of substrate layer (silica-deposited PET) / detachable primer layer (S1) / ink layer (I2) / detachable adhesive layer (T1) / substrate layer (NY) / detachable adhesive layer (T1) / substrate layer (CPP).

[0147] [Manufacturing Example 3-21] (Laminated film L21) The diluted primer composition S1 and printing ink I2 were printed in that order over the entire surface of an OPP (thickness 20 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a structure of OPP / S1 / I2. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After coating and drying, the film was laminated to the vapor-deposited surface of a transparent silica-deposited PET sheet (thickness 12 μm). Next, adhesive T1 was applied to the PET film surface of the obtained laminated film in the same manner as above, with a coating amount of 3.0 g / m2 after drying. 2 After coating and drying, the film was attached to a CPP (thickness: 30 μm). Next, the obtained laminated film was kept at 40°C for 3 days to obtain a laminated film L21 having a structure of substrate layer (OPP) / detachable primer layer (S1) / ink layer (I2) / detachable adhesive layer (T1) / substrate layer (silica-deposited PET) / detachable adhesive layer (T1) / substrate layer (CPP).

[0148] [Manufacturing Example 3-22] (Laminated film L22) The diluted primer composition S1 and printing ink I2 were printed in that order over the entire surface of an OPP (thickness 20 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a structure of OPP / S1 / I2. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After applying and drying the coating, the coating was attached to the vapor-deposited surface of an aluminum (AL)-deposited PET sheet (thickness 12 μm). Next, adhesive T1 was applied to the PET film surface of the obtained laminated film in the same manner as above, with a coating amount of 3.0 g / m2 after drying. 2 After coating and drying, the film was attached to a CPP (thickness: 25 μm). Next, the obtained laminated film was kept at 40°C for 3 days to obtain a laminated film L22 having a structure of substrate layer (OPP) / detachable primer layer (S1) / ink layer (I2) / detachable adhesive layer (T1) / substrate layer (aluminum-vapor-deposited PET) / detachable adhesive layer (T1) / substrate layer (CPP).

[0149] [Manufacturing Example 3-23] (Laminated film L23) The diluted primer composition S1 and printing ink I2 were printed in that order over the entire surface of PET (thickness 12 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a structure of PET / S1 / I2. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After applying and drying the coating, the coating was attached to the aluminum-deposited surface of a PET sheet (thickness: 12 μm). Next, adhesive T1 was applied to the aluminum vapor deposition surface of the obtained laminated film in the same manner as above, with a coating amount of 3.0 g / m2 after drying. 2 After coating and drying, the laminate was laminated to LLDPE (thickness 150 μm). Next, the obtained laminated film was kept at 40°C for 3 days to obtain a laminated film L23 having a structure of substrate layer (PET) / detachable primer layer (S1) / ink layer (I2) / detachable adhesive layer (T1) / substrate layer (aluminum-vapor-deposited PET) / detachable adhesive layer (T1) / substrate layer (LLDPE).

[0150] [Manufacturing Example 3-24] (Laminated film L24) The diluted primer composition S1 and the printing ink I2 were printed on the entire surface of a PET sheet (thickness 12 μm) in this order using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm. After drying at 0° C., a laminated film having a structure of PET / S1 / I2 was obtained. Next, adhesive T4 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After coating and drying, the resulting mixture was laminated to AL (aluminum foil, thickness 7 μm). Next, adhesive T1 was applied to the AL surface of the obtained laminated film in the same manner as above, with a coating amount of 3.0 g / m2 after drying. 2 After coating and drying, the film was attached to a CPP (thickness 70 μm). Next, the obtained laminated film was kept at 40°C for 3 days to obtain a laminated film L24 having a structure of substrate layer (PET) / detachable primer layer (S1) / ink layer (I2) / adhesive layer (T4) / substrate layer (AL) / detachable adhesive layer (T1) / substrate layer (CPP).

[0151] [Manufacturing Example 3-25] (Laminated film L25) The diluted primer composition S1 and printing ink I2 were printed in that order over the entire surface of PET (thickness 12 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a structure of PET / S1 / I2. Next, adhesive T4 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After coating and drying, the film was attached to an aluminum foil (thickness 7 μm). Next, adhesive T1 was applied to the AL surface of the obtained laminated film in the same manner as above, with a coating amount of 3.0 g / m2 after drying. 2 After coating and drying, the film was attached to NY (thickness 15 μm). Next, adhesive T1 was applied to the NY side of the obtained laminated film in the same manner as above, with a coating amount of 3.0 g / m2 after drying. 2 After coating and drying, the film was attached to a CPP (thickness 70 μm). The obtained laminated film was then kept at 40°C for 3 days to obtain a laminated film L25 having a structure of substrate layer (PET) / detachable primer layer (S1) / ink layer (I2) / adhesive layer (T4) / substrate layer (AL foil) / detachable adhesive layer (T1) / substrate layer (NY) / detachable adhesive layer (T1) / substrate layer (CPP).

[0152] [Manufacturing Example 3-26] (Laminated film L26) The diluted primer composition S1 and printing ink I2 were printed in that order over the entire surface of PET (thickness 12 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a structure of PET / S1 / I2. Next, adhesive T4 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After coating and drying, the film was attached to an aluminum foil (thickness 7 μm). Next, adhesive T1 was applied to the AL surface of the obtained laminated film in the same manner as above, with a coating amount of 3.0 g / m2 after drying. 2 After coating and drying, the film was attached to NY (thickness 15 μm). Next, adhesive T1 was applied to the NY side of the obtained laminated film in the same manner as above, with a coating amount of 3.0 g / m2 after drying. 2 After coating and drying, the laminate was laminated with LLDPE (thickness 100 μm). Next, the obtained laminated film was kept at 40°C for 3 days to obtain a laminated film L26 having a structure of substrate layer (PET) / detachable primer layer (S1) / ink layer (I2) / adhesive layer (T4) / substrate layer (AL foil) / detachable adhesive layer (T1) / substrate layer (NY) / detachable adhesive layer (T1) / substrate layer (LLDPE).

[0153] [Manufacturing Example 3-27] (Laminated film L27) The diluted primer composition S1 and printing ink I2 were printed in that order over the entire surface of PET (thickness 12 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and then dried at 50° C. to obtain a laminated film having a structure of PET / S1 / I2. Next, adhesive T1 was applied onto the ink layer of the resulting laminated film using a dry laminator so that the coating amount after drying was 3.0 g / m 2 After applying and drying the coating, the coating was attached to the aluminum-deposited surface of a PET sheet (thickness: 12 μm). Next, adhesive T1 was applied to the PET surface of the obtained laminated film in the same manner as above, with a coating amount of 3.0 g / m2 after drying. 2 After coating and drying, the film was attached to NY (thickness 15 μm). Next, adhesive T1 was applied to the NY side of the obtained laminated film in the same manner as above, with a coating amount of 3.0 g / m2 after drying. 2 After coating and drying, the laminate was laminated to LLDPE (thickness 70 μm). Next, the obtained laminated film was kept at 40°C for 3 days to obtain a laminated film L27 having a structure of substrate layer (PET) / detachable primer layer (S1) / ink layer (I2) / detachable adhesive layer (T1) / substrate layer (aluminum-deposited PET) / detachable adhesive layer (T1) / substrate layer (NY) / detachable adhesive layer (T1) / substrate layer (LLDPE).

[0154] [Table 4]

[0155] The abbreviations in Table 4 are as follows: Transparent vapor-deposited PET: Transparent silica vapor-deposited PET VMPET: Aluminum-deposited PET

[0156] <Method of separating and recovering laminated film> The following describes the conditions of steps (1) and (4) in Tables 5 to 7. In addition, in all of the examples and comparative examples, laminated films cut to a size of 35 cm x 35 cm were used.

[0157] [Process (1)] (shredding device) Wet type (1): PFS-40 model manufactured by Nippon Seam (a vertical shredding device equipped with a cutter mill and a circular screen with a diameter of 15 mm). The shredding process was carried out while water was flowing in from the water inlet. Wet method (2): Nikuni Sancutter C80H (a horizontal shredding device equipped with a cutter mill and a circular screen with a diameter of 15 mm) was used. In this specification, the laminated film was shredded and the resin substrate layer was separated at the same time while a 2% by mass aqueous sodium hydroxide solution was flowed in from the water inlet. Dry type: Horai FG-2060 (equipped with a cutter mill and a 15 mm diameter circular screen).

[0158] (mass of laminated film) The mass of laminated film fed into the laminated film feed port of the shredding device in one minute.

[0159] (mass of water) The mass of water fed into the shredder's water inlet per minute.

[0160] (water cooling temperature) The temperature of the water entering the shredder at its water inlet.

[0161] [Process (4)] (Washing and filtration process) In the washing and filtering process, a washing and filtering device (Nihon Seam SW-408 type) equipped with a circular filtering screen having a diameter of 3 mm was connected to the shredding device, and water washing and filtering were performed continuously.

[0162] [Example 1] 1.2 kg of laminated film L1 (35 cm x 35 cm) was fed into a wet shredding device (wet type (1)) equipped with a circular screen with a diameter of 15 mm at a rate of 1.2 kg / min, and shredded while feeding water controlled to a temperature of 20°C using a cooling device at a rate of 60 kg / min, and then passed through the screen to obtain shredded material (step (1)). The long side of the obtained shredded material was 15 mm or less. Next, the shredded material was transported to a cleaning and filtering device (SW-408 model, manufactured by Nippon Seam) directly connected to the shredding device, where the shredded material was washed with water and fine pieces with a diameter of 3 mm or less that were generated during shredding were removed (step (4)). Next, 1500 ml of a 2% by mass aqueous solution of sodium hydroxide at 70° C. was added to a 2000 ml flask, and 30 g of the obtained shredded material was immersed in the solution. The solution was stirred at 70° C. and 200 rpm for 2 hours to separate the resin substrate layer (step (2)). Next, the separated resin substrate layer (OPP) was recovered using a gravity separation method, washed with water, and dried (step (3)).

[0163] [Examples 2 to 6, Examples 11 to 40, Comparative Examples 1 to 2, and Comparative Examples 4 to 9] Separation and recovery of the laminated film was carried out in the same manner as in Example 1, except that the type of laminated film and the conditions of steps (1) and (4) were changed to those shown in Tables 5 and 7. When the separated resin substrate layer was an olefin, it was recovered using a gravity separation method, and when it was PET or NY, it was recovered using a filter, washed with water, and dried.

[0164] [Example 7] 1.2 kg of laminated film L3 (35 cm x 35 cm) was fed into a wet shredding device (wet type (1)) equipped with a circular screen with a diameter of 15 mm at a rate of 1.2 kg / min, and shredded while feeding water controlled to a temperature of 20°C using a cooling device at a rate of 60 kg / min, and then passed through the screen to obtain shredded material (step (1)). The long side of the obtained shredded material was 15 mm or less. Next, the shredded material was transported to a cleaning and filtering device (SW-408 model, manufactured by Nippon Seam) directly connected to the shredding device, where the shredded material was washed with water and fine pieces with a diameter of 3 mm or less that were generated during shredding were removed (step (4)). Next, 1500 ml of water at 70° C. was added to a 2000 ml flask, and 30 g of the obtained shredded material was immersed in the water. The mixture was stirred at 70° C. and 200 rpm for 2 hours to separate the resin substrate layer (step (2)). Next, the separated resin substrate layer (OPP) was recovered using a gravity separation method, washed with water, and dried (step (3)).

[0165] [Examples 8 to 10, Comparative Example 3] The laminated film was separated and recovered in the same manner as in Example 7, except that the type of laminated film and the conditions of steps (1) and (4) were changed to those shown in Table 6.

[0166] [Comparative Example 10] 1.2 kg of laminated film L5 (35 cm x 35 cm) was fed at a rate of 1.2 kg / min into a wet shredding and separation device (wet type (2)) equipped with a circular screen with a diameter of 15 mm, and a 2% by mass aqueous sodium hydroxide solution controlled to a temperature of 20°C using a cooling device was fed at a rate of 60 kg / min to perform shredding and separation at the same time. The film was then passed through the screen to obtain a resin substrate layer separated from the shredded material. The long side of the obtained resin substrate layer was 15 mm or less. Next, the separated resin substrate layers (OPP, CPP) were collected using a gravity separation method, washed with water, and dried.

[0167] [Comparative Example 11] Separation and recovery of the laminated film was carried out in the same manner as in Comparative Example 10, except that the conditions for the shredding and separation steps were changed to those shown in Table 7.

[0168] <Evaluation of Recovered Resin Substrate Layer> The collected resin substrates were evaluated for ink releasability and removal rate. The laminated films bonded with an adhesive were evaluated for laminate peelability and adhesive removal rate. The results are shown in Tables 5 to 7.

[0169] (Ink releasability) For the examples using a laminated film having a removable primer layer and / or a removable ink layer on a substrate, 10 substrates printed with the separated removable primer layer and / or removable ink layer were randomly sampled, and the detached area of ​​the ink layer was visually confirmed and evaluated according to the following criteria. A rating of 3 or more is within the usable range. 5 (Excellent): Peeling area is 90% or more 4 (Good): Peeling area is 80% or more but less than 90% 3 (OK): Peeling area is 60% or more but less than 80% 2 (Not acceptable): Peeling area is 20% to less than 60% 1 (Not acceptable): Peeling area is less than 20%

[0170] (Primer and ink removal rate) For the 10 substrates used in the ink releasability evaluation, FT-IR was measured at two locations per substrate to confirm the presence or absence of absorption peaks derived from the primer or ink. The percentage of no absorption peaks detected (removal rate) was calculated for a total of 20 locations, and evaluated according to the following criteria. For example, if no absorption peaks were detected in 19 of the 20 locations, the removal rate is 95%. An evaluation criterion of 3 or higher is within the usable range. 5 (Excellent): Removal rate is 90% or more 4 (Good): Removal rate is 80% to less than 90% 3 (Acceptable): Removal rate is between 60% and 80% 2 (Not acceptable): Removal rate is between 20% and 60% 1 (Not acceptable): Removal rate is less than 20%

[0171] (Adhesive removal rate) For the examples using a laminated film with a removable adhesive layer, 10 substrates to be recovered that were in contact with the removable adhesive layer were randomly sampled, and FT-IR was measured at two locations per substrate to confirm the presence or absence of an absorption peak derived from the adhesive. The proportion of no absorption peaks detected (removal rate) was calculated for a total of 20 locations, and evaluated according to the following criteria. For example, if no absorption peaks were detected at 19 locations out of 20 locations, the removal rate is 95%. The evaluation criteria for usability are 3 or higher. 5 (Excellent): Removal rate is 90% or more 4 (Good): Removal rate is 80% to less than 90% 3 (Acceptable): Removal rate is between 60% and 80% 2 (Not acceptable): Removal rate is between 20% and 60% 1 (Not acceptable): Removal rate is less than 20%

[0172] (Laminate peelability) For the examples using a laminated film with a removable adhesive layer, 30 substrates to be recovered that were in contact with the removable adhesive layer were randomly sampled, and the number of laminated films in which the substrates were not peeled off was counted and evaluated according to the following criteria. A rating of 3 or higher was considered to be within the usable range. 5 (Excellent): One or less laminated films are not peeled off 4 (Good): 2 to 3 sheets of laminated film that have not peeled off 3 (Acceptable): 4 to 6 unpeeled laminated films 2 (Not acceptable): 7 to 15 sheets of unpeeled laminated film 1 (Not acceptable): 16 or more unpeeled laminated films

[0173] [Table 5]

[0174] [Table 6]

[0175] [Table 7]

[0176] From the above evaluation results, by continuously adding water at 50℃ or less during the shredding process, The laminate obtained by cutting into thin strips while cooling with water at 50° C. or less maintained the exposed detached layer on the thin cut surface, allowing the resin substrate layer to be efficiently separated and recovered. In particular, when the mass of water used in the shredding process was 2 or more based on the mass of the laminated film, the laminate peelability improved. This is presumably because the thin cut surface was exposed by suppressing the fusion of the film during shredding, and the separation of the resin substrate proceeded efficiently (Examples 11, 14 to 16). In addition, by having a washing and filtering process after the shredding process, fine pieces of ink and adhesive components generated in the shredding process were removed and adhesion to the substrate was suppressed, resulting in excellent separation and recovery of the resin substrate in the subsequent separation process (Examples 11 and 18). On the other hand, when a dry shredding device (dry type) was used, the laminated films were fused together during shredding, and the release liquid did not penetrate into the laminated film in the subsequent separation process, resulting in a decrease in separation and recovery efficiency of the resin substrate (Comparative Examples 1 to 3 and 5 to 9). When a wet-type shredding device (wet type (2)) that simultaneously performs the shredding and separation processes was used, the residence time of the laminated film was short, so the film was not sufficiently removed. Furthermore, fine pieces of ink and adhesive components generated during shredding adhered to the substrate, reducing the removal rate (Comparative Examples 10 and 11).

Claims

1. A method for separating and recovering a laminated film having at least a resin substrate layer and a release layer, the method comprising the following steps (1) to (4): (1) A shredding step in which the laminated film is shredded while being cooled with water whose liquid temperature is set to 50°C or less using a cooling means to obtain shredded material. (2) A separation step of immersing the shredded material in a release solution to separate the resin substrate layer. (3) A recovery step of recovering the separated resin substrate layer (4) A washing and filtering step in which the shredded material is washed with water to remove ink particles and / or adhesive particles. However, the mass of water used in the step (1) is 10 to 500 times the mass of the laminated film, and the step (4) is provided between the step (1) and the step (2), and the step (4) includes a filtration step using a filter screen.

2. The method for separating and recovering a laminated film according to claim 1 , wherein the detachment layer is a layer containing a compound having an acidic group.

3. The method for separating and recovering a laminated film according to claim 1 or 2, wherein the detachment layer is a layer containing a water-soluble resin.

4. 3. The method for separating and recovering a laminated film according to claim 1, wherein the laminated film has a partial structure including a resin substrate layer, a primer layer, and an ink layer in this order, and the primer layer is a release layer.

5. 3. The method for separating and recovering a laminated film according to claim 1, wherein the laminated film has a partial structure in which two resin substrate layers are laminated via an adhesive layer, and the adhesive layer is a release layer.

6. 3. The method for separating and recovering a laminated film according to claim 1, wherein the laminated film has a partial structure including a resin substrate layer and an ink layer in this order, and the ink layer is a release layer.