JP7318790B1 - Method for separating and collecting fluff and resin base material - Google Patents

Abstract

Kind Code: A1 An object of the present invention is to provide a method for obtaining a recycled material with high efficiency and high physical properties by giving a size distribution to a film after crushing. SOLUTION: A fluff of a laminated body having at least a resin substrate layer and a layer other than the resin substrate layer, wherein the fluff has an average size of 10 mm or more, and the standard deviation of the size distribution of the fluff is A laminate fluff in which the fluff that is 10 mm or more and does not pass through a 3 mm sieve accounts for 60% by weight or more of the total fluff. A fluff obtained by detaching a layer other than the resin base layer from a laminate having at least a resin base layer and a layer other than the resin base layer by contacting with a desorption liquid, wherein the average size of the fluff is , 10 mm or more, the standard deviation of the size distribution of the fluff is 10 mm or more, and the fluff that does not pass through a 3 mm sieve is 60% by weight or more of the total fluff. [Selection figure] None

Description

TECHNICAL FIELD The present invention relates to a fluff comprising at least a resin substrate layer and a release layer, and a resin substrate separation and recovery method.

In recent years, packages, plastic bottles, and other plastic products made from plastic film have been discarded or dumped into the ocean as garbage, causing environmental pollution problems. These plastic products are decomposed in seawater to become submicron-sized fragments (microplastics) and float in seawater. When these microplastics are ingested by marine organisms such as fish, they are concentrated in the bodies of the organisms, and there is concern that they may affect the health of seabirds and humans who consume these marine organisms as food.

Examples of the plastic products include multi-layered food packaging packages using plastic films. In such food packaging packages, polyester base material, nylon base material (NY), polypropylene base material ( PP), polyethylene base material (PE), etc., various resin base materials are used. These film substrates are printed with printing ink, bonded to other film substrates or hot-melt resin substrates via an adhesive or the like, cut and heat-sealed to form a package. However, such a multi-layered food packaging package has a problem that material recycling cannot be performed as it is because a plurality of incompatible different materials are mixed.

As an attempt to solve environmental problems caused by plastics, for example, Patent Document 1 discloses that a laminate having a resin substrate and a release layer is shredded and then brought into contact with a release liquid to remove the release layer. is detached and a method for recovering the detached resin substrate is described.
Further, for example, Patent Literature 2 describes a method of crushing a laminate having a resin base material and a detachable layer with a detaching liquid, detaching the detached layer, and recovering the detached resin base material. ing.

Japanese Patent No. 6631964 International Publication No. 2022/190872

In the present invention, "fluff" refers to at least a product obtained by shredding or crushing a sheet or the like, and is a laminate having a resin substrate layer and layers other than the resin substrate layer. In a typical form, a layer other than the resin base layer is removed by contacting with a desorption liquid (a layer other than the resin base layer removed by the desorption liquid is hereinafter also referred to as a “desorption layer”). It is a fluff used for the purpose of recovering a high-purity resin base material (hereinafter also referred to as "recycled material"). The resin substrate layer may be a single layer or multiple layers. When the resin base material layer is a plurality of layers, the resin base material to be recovered may be one in which part or all of the resin base layer is separated, or may be a plurality of layers as they are. .
An object of the present invention is to provide a highly efficient method for obtaining a regenerated material having high physical properties by imparting a size distribution to fluff after crushing.
The present invention is characterized in that the "fluff" has a specific size and that the surface size of the "fluff" has a distribution in the desorbing liquid during the desorption step. The size of the surface of the "fluff" of the laminate before contact and the size of the surface of the resin base material recovered by detachment of the detachment layer are substantially the same.
In Patent Document 1, the fluff is chopped into a specific size before contacting the desorbing liquid, and the fluff is uniform in size, and the standard deviation of the fluff size distribution is less than 10 mm.
In Patent Document 2, the size of the fluff fluctuates during contact with the desorbing liquid, but according to the above definition, the "fluff" immediately before the final desorption occurs matches the "fluff" after desorption. do. Therefore, it is assumed that the average size of the fluff is much smaller than 10 mm and that the fluff sizes are uniform and the standard deviation of the fluff size distribution will be less than 10 mm.

The present invention provides fluff obtained by crushing at least a laminate having a resin base layer and a layer other than the resin base layer and having an average size of 10 mm or more and a standard deviation of the size of 10 mm or more, and further 3 mm. It relates to the fluff of the laminate in which the fluff that does not pass through the sieve is 60% or more by weight of the total fluff.

Further, the present invention provides a laminate having at least a resin substrate layer and a layer other than the resin substrate layer,
A fluff from which a layer other than the resin base layer is detached by contact with a desorption liquid,
The average size of the fluff is 10 mm or more,
The standard deviation of the fluff size distribution is 10 mm or more,
Fluff that does not pass through a 3 mm sieve is 60% or more by weight of the total fluff.

The present invention also relates to any one of the above fluff, wherein the resin substrate layer contains an olefin resin.

Further, the present invention crushes a laminate having at least a resin base layer and a layer other than the resin base layer,
A step of fluffing the laminate,
a step of contacting the fluff with a desorption liquid to desorb layers other than the resin base layer;
And, including a step of recovering the desorbed resin base material,
The present invention relates to a method for recovering a resin base material.

The fluff of the present invention has an average size of 10 mm or more, a standard deviation of the size distribution of the fluff of 10 mm or more, and a fluff that does not pass through a 3 mm sieve accounts for 60% by weight or more of the entire fluff. As a result, in the production of recycled materials, it has become possible to process a large amount at one time while suppressing deterioration of the mechanical properties of the recycled materials.

<Laminate>
The laminate in the present invention has at least a resin base layer and layers other than the resin base layer, and the layers other than the resin base layer are arranged in contact with the resin base layer. The resin substrate layer represents the substrate recovered after the separation step, and the desorption layer is desorbed (also referred to as peeling) from the resin substrate layer by immersion in a desorption liquid to separate the resin substrate layer. play a role in contributing to

<Layers other than the resin base layer>
The layers other than the resin substrate layer used in the present invention are not particularly limited in material, as long as they are crushed together with the resin substrate layer to form a specific Okisano fluff.
Moreover, the case where the layer other than the resin base layer is not the release layer is not excluded.
For example, the resin base material may be collected without detaching layers other than the resin base material layer from the resin base material layer.
In addition, the laminate composed of the resin substrate layer/layer other than the resin substrate layer/resin substrate layer is the laminate 1 composed of the resin substrate layer/layer other than the resin substrate layer, and the laminate other than the resin substrate layer. layer/resin substrate layer, but the resin substrate may be recovered without detaching the layers other than the fat substrate layer. In these, layers other than the resin substrate layer are not release layers.
However, when the layer other than the resin substrate layer is a release layer, it is preferable in terms of increasing the purity of the recovered resin substrate.

<Detachment layer>
The detachable layer in the present invention may be a layer that can be detached from the resin substrate layer with a known detachment liquid, and is preferably a layer containing a water-soluble resin, a compound having an acidic group (however, the water-soluble resin ), a metal deposition layer, or an inorganic oxide (metal oxide) deposition layer. From the viewpoint of substrate versatility, the release layer is more preferably a layer containing a compound having an acidic group. Moreover, from the viewpoint of reducing the environmental burden, the desorption layer is more preferably a layer containing a water-soluble resin.

When the release layer is a metal vapor deposition layer or an inorganic oxide (metal oxide) vapor deposition layer, the vapor deposition layer is preferably formed on the resin substrate layer.
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 therefore preferably includes a primer layer, an ink layer and an adhesive layer. It is at least one layer selected from the group consisting of agent layers. That is, at least one layer selected from the group consisting of a primer layer, an ink layer and an adhesive layer is preferably 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. One of these water-soluble resins or compounds having an acidic group may be used alone, or two or more thereof may be used in combination.

At least one layer selected from the group consisting of the primer layer, the ink layer and the adhesive layer is composed of a resin component (hereinafter also referred to as a binder resin) that is a water-soluble resin or a resin having an acidic group. and may contain a binder resin and a low-molecular-weight compound having an acidic group.
Hereinafter, the case where the release layer is a primer layer, an ink layer, or an adhesive layer will be described.

[Desorption primer layer]
When the detachable layer is a primer layer, the primer layer is arranged in contact with the resin base layer and plays a role of detaching the resin base layer by dissolution, peeling, or the like with a detachment liquid. The primer layer preferably contains a water-soluble resin or a compound having an acidic group.

(Water-soluble resin)
As the water-soluble resin, any resin that can be swollen or dissolved in water and detached from the resin substrate layer may be used. The water may be heated to a temperature of about 25-100°C. Thereby, the primer layer can be removed with water (including warm water).
Such resins can be selected from known resins as long as they do not impair water solubility. polyallylamine resins, water-soluble phenol 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 singly or in combination of two or more. Among them, polyvinyl alcohol (PVA) resin is preferably used from the viewpoint of availability and releasability.
When the water-soluble resin has film-forming properties, the water-soluble resin may be used as the binder resin constituting the primer layer.

Polyvinyl alcohol resins include, in addition to unmodified polyvinyl alcohol, modified polyvinyl alcohol obtained by copolymerizing various monomers during the production of vinyl ester resins and saponifying them, and various types of polyvinyl alcohol obtained by post-modification of unmodified polyvinyl alcohol. Various post-modified polyvinyl alcohols into which functional groups have been introduced may be used. Also, modified polyvinyl alcohol may be post-modified. These modification|denaturation can be performed in the range which does not impair the water-solubility of polyvinyl alcohol resin.
These resins may be used individually by 1 type, and may use 2 or more types together.

Preferable polyvinyl alcohol resins include resins containing structural units having primary hydroxyl groups in side chains and ethylene-modified polyvinyl alcohol resins. Among them, a polyvinyl alcohol resin containing a structural unit having a primary hydroxyl group in a side chain is preferable because of its excellent water solubility. The number of primary hydroxyl groups in these structural units is generally 1-5, preferably 1-2, more preferably 1. Moreover, it is preferable to have a secondary hydroxyl group in addition to the primary hydroxyl group.

The degree of saponification (measured according to JIS K 6726) of the polyvinyl alcohol resin used in the present invention is usually 60 to 100 mol%. In addition, the preferred range of saponification degree varies depending on the modified species. 0.5%. The saponification degree of the side chain 1,2-diol structural unit-containing modified polyvinyl alcohol resin is usually 60 to 99.9 mol%, preferably 65 to 99.8 mol%, more preferably 70 to 99.5 mol%. be. If the degree of saponification 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 %.
When the degree of saponification is within the above range, the water solubility is excellent and the releasability is improved, which is preferable. Moreover, it is preferable because it is excellent in coatability when forming a primer layer.

The average degree of polymerization of the polyvinyl alcohol resin (measured according to JIS K 6726) is generally 100-3000, preferably 150-2000, more preferably 180-1000, particularly preferably 200-800.

(Compound having an acidic group)
As the compound having an acidic group, a resin having an acidic group or a low-molecular-weight compound having an acidic group may be used. As a result, the primer layer can be removed with the basic aqueous solution described above.

Examples of resins having an acidic group include cellulose resins, urethane resins, polyamide resins, vinyl chloride/vinyl acetate copolymers, ketone resins, polyester resins, and (meth)acrylic resins. Examples of the acidic group include a carboxy group, a phosphoric acid group, a sulfo group, a sulfino group, etc., or an ester or salt thereof.
As the resin having an acidic group, a rosin-modified resin having an acid value such as maleated rosin and fumarated rosin can be used.
In addition, as the resin having an acidic group, a polymerizable monomer having a carboxy group such as itaconic acid, maleic acid, fumaric acid, and cinnamic acid; a polymerizable monomer that is an acid anhydride such as itaconic anhydride and maleic anhydride; Polymerizable monomers having a sulfonic acid group such as styrene; Polymerizable monomers having a sulfonamide group such as vinylbenzenesulfonamide; Polymerizable monomers having an acidic group such as styrene-(meth)acrylic Resins, radical copolymers such as styrene-(anhydride) maleic acid resins and terpene-(anhydride) maleic acid resins, and acid-modified polyolefin resins can be used.
These may be used individually by 1 type, and may use 2 or more types together.

A low-molecular-weight compound having an acidic group refers to a compound having no molecular weight distribution and having 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; 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; oxalic acid, Dicarboxylic acids such as 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.
A low-molecular-weight compound having an acidic group can be used in combination with a resin having an acidic group or a known binder resin constituting a known primer layer to form a primer layer.

From the viewpoint of suitability for recoating, the primer layer preferably contains a compound having an acidic group. In addition, from the viewpoint of printability, it is preferable to include a urethane resin having an acidic group, an acrylic resin having an acidic group, and a rosin-modified resin.

[Urethane resin having an acidic group]
The urethane resin having an acidic group is not particularly limited, and for example, a urethane resin obtained by reacting a polyol having an acidic group with a polyisocyanate, or a urethane resin obtained by reacting a polyol with a polyisocyanate, the hydroxyl groups in the urethane resin are acid-modified. and a resin obtained by acid-modifying the amino group in a urethane urea resin obtained by reacting an isocyanate group in a urethane resin obtained by reacting a polyol and a polyisocyanate with a polyamine.
As the urethane resin having an acidic group, a resin obtained by reacting a polyol containing a hydroxy acid and a polyisocyanate may be used. By using a hydroxy acid as a polyol, an acid value derived from a carboxy group can be imparted to the urethane resin, and the releasability can be improved. Further, when the urethane resin having an acidic group has an isocyanate group, a part of the isocyanate group may be reacted with a polyamine to introduce a urea bond to form a urethane urea.

《Polyol》
Polyol is a general term for compounds having at least two hydroxyl groups in one molecule. The number average molecular weight of the polyol is preferably 500-10,000, more preferably 1,000-5,000. The number average molecular weight is calculated from the hydroxyl value of the polyol, and the hydroxyl value refers to the value measured according to JISK0070. 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 polyolefin substrates is excellent.

The polyol is not particularly limited, and more preferably at least one polyol selected from the group consisting of polyester polyols, polyether polyols and polycarbonate polyols. Furthermore, the polyol may also include other dimer diols, hydrogenated dimer diols, castor oil-modified polyols, and the like.
That is, the urethane resin preferably contains at least one polyol-derived structural unit selected from the group consisting of polyester polyols, polyether polyols, and polycarbonate polyols. More preferably, it contains a structural unit derived from a polyester polyol, since alkali hydrolysis of the ester bond site of the polyester polyol improves the releasability.
The content of the polyol-derived structural unit is preferably 10 to 75% by mass, more preferably 15 to 70% by mass, still more preferably 20 to 65% by mass, based on the total amount of the urethane resin. The content of polyester polyol-derived structural units is preferably 5% by mass or more, more preferably 30% by mass or more, still more preferably 60% by mass or more, and particularly preferably 80% by mass, based on the total amount of polyol-derived structural units. That's it.

《Hydroxy acid》
The polyols may contain hydroxy acids. 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, a sulfonic acid group, and the like, preferably a carboxy group. As such hydroxy acids, dimethylolalkanoic acids such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and 2,2-dimethylolvaleric acid are preferably used.

《Polyisocyanate》
The polyisocyanate is not particularly limited and can be selected from conventionally known polyisocyanates. Preferably, it contains diisocyanates or triisocyanates, more preferably aromatic, aliphatic or cycloaliphatic diisocyanates. These may be used alone or in combination of two or more.

《Polyamine》
Polyamines for forming urethane urea are not particularly limited, and diamine compounds are preferred. In addition, a diamine having a hydroxyl group may be used in that a hydroxyl group can be introduced into the urethane resin.

The acid value of the urethane resin having acidic groups is preferably 15 mgKOH/g or more, more preferably 15 to 70 mgKOH/g, still more preferably 20 to 50 mgKOH/g. When it is 15 mgKOH/g or more, the detachability with a desorbing liquid is favorable, and when it is 70 mgKOH/g or less, it is preferable because substrate adhesion and retort resistance are improved. The hydroxyl value of the urethane resin is preferably 1-35 mgKOH/g, more preferably 10-30 mgKOH/g. When it is 1 mgKOH/g or more, it is preferable because the detachability by the detachment liquid is improved, and when it is 35 mgKOH/g or less, it is preferable because the adhesion to the substrate is improved.

The urethane resin having an acidic group preferably has a weight average molecular weight of 10,000 to 100,000, more preferably 15,000 to 70,000, still 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, the drying property of the primer composition, and the suitability for retort resistance are excellent. In addition, the smaller the molecular weight distribution, that is, the sharper the molecular weight distribution, the more uniformly the dissolution and peeling action by the desorption liquid occurs, and the detachability of the resin substrate layer is improved. The molecular weight distribution is more preferably 5 or less, still more preferably 4 or less. Also, the molecular weight distribution is preferably 1.5 or more, more preferably 1.2 or more.
In the present specification, Mw, Mn and molecular weight distribution (Mw/Mn) are polystyrene equivalent values determined by gel permeation chromatography (GPC).

A 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, more preferably 1 to 10 mgKOH/g. Within the above range, the adhesiveness to the substrate is excellent.

The number of urethane bonds in the polyurethane resin having an acidic group is preferably 1-3 mmol/g, more preferably 1.5-2 mmol/g. Also, the number of urea bonds is preferably 0 to 3 mmol/g, more preferably 0.2 to 1 mmol/g. Also, 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 relevant ranges, the releasability and substrate adhesion are improved.

[Acrylic resin having an acidic group]
The acrylic resin having an acidic group includes, for example, a polymer obtained by polymerizing a monomer containing a (meth)acrylic monomer having an acidic group such as (meth)acrylic acid and maleic acid; a (meth)acrylic monomer having a hydroxyl group or a glycidyl group. After polymerizing a monomer containing, the functional group is modified to introduce a carboxyl group (for example, a maleic anhydride-modified resin);
The acid value of the acrylic resin having acidic groups is preferably 50 mgKOH/g or more, more preferably 100 mgKOH/g or more.

[Rosin modified resin]
A rosin-modified resin is a resin prepared using rosin as one of raw materials. Rosin contains a mixture of resin acids such as abietic acid, parastric acid, isopimaric acid, levopimaric acid, etc. These resin acids contain hydrophilic and chemically active carboxyl groups, some of which have conjugated double bonds. Some are prepared. Therefore, polyhydric alcohols and polybasic acids are combined for condensation polymerization, phenolic condensate resol is added to the benzene ring contained in the rosin skeleton, and dienophile maleic anhydride and maleic acid undergo Diels-Alder reaction. Various rosin-modified resins have been prepared by adding a maleic acid or maleic anhydride skeleton by allowing the Various types of such rosin-modified resins are commercially available, and it is also possible to obtain and use them.

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. In the present invention, any rosin-modified resin may be used, but among these, at least one selected from the group consisting of maleic acid, maleic anhydride, fumaric acid and fumaric anhydride in its structure Those containing a portion to be used are preferably used. A resin that "contains a site derived from at least one selected from the group consisting of maleic acid, maleic anhydride, fumaric acid and fumaric anhydride in its structure" means maleic acid and maleic anhydride as part of raw materials. It is prepared using at least one selected from the group consisting of acid, fumaric acid and fumaric anhydride, for example, rosin-modified malein obtained by condensation polymerization of maleic acid or fumaric acid as part of the polybasic acid Acid resins, rosin-modified fumaric acid resins, maleic rosins and fumaric rosins having a structure obtained by adding maleic acid, maleic anhydride, fumaric acid, or fumaric anhydride as a dienophile by Diels-Alder reaction, fumaric rosins, and functional groups contained therein. It means a resin or the like obtained by further polymerizing another chemical species using a group.

The acid value of the rosin-modified resin is preferably 10-400 mgKOH/g, more preferably 100-300 mgKOH/g.

(Other ingredients)
The primer layer may contain a resin other than a water-soluble resin or a 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, and vinyl acetate resins. , acrylic resin, styrene resin, dammar resin, styrene-acrylic copolymer resin, polyester resin, alkyd resin, terpene resin, phenol-modified terpene resin, ketone resin, cyclized rubber, chlorinated rubber, butyral, polyacetal resin, petroleum resin, and These modified resins can be mentioned. These resins may be used individually by 1 type, and may use 2 or more types together.
Among them, the primer layer preferably contains at least one resin selected from the group consisting of cellulose resins, vinyl chloride resins, rosin resins, and acrylic resins. More preferably, vinyl chloride resin or acrylic resin is included.
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. Within the above range, when the ink layer is peeled off together with the primer layer in a basic aqueous solution, the ink layer is peeled off in the form of a thin film, which facilitates recovery, which is preferable.

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

The primer layer may be a layer in which the above-described urethane resin having an acidic group is crosslinked with a curing agent. By introducing a crosslinked structure into the primer layer, the ink layer formed on the primer layer is prevented from permeation and bleeding, and excellent image quality can be exhibited.
Curing agents include, for example, polyisocyanates. The polyisocyanate is not particularly limited and can be selected from conventionally known polyisocyanates, such as aliphatic polyisocyanates and araliphatic polyisocyanates. These may be used alone or in combination of two or more.

The primer layer may further contain known additives. Known additives include, for example, dispersants, wetting agents, adhesion aids, leveling agents, antifoaming agents, antistatic agents, viscosity modifiers, metal chelates, trapping agents, antiblocking agents, wax components other than the above, A silane coupling agent is mentioned.

The thickness of the primer layer is preferably 0.5 to 3.0 μm, more preferably 0.6 to 2.0 μm, still more preferably 0.8 to 1.5 μm, and is formed by a known method. be able to.

[Detachable ink layer]
The ink layer is a layer that forms an arbitrary printed pattern for the purpose of decoration, imparting aesthetics, content, expiration date, manufacturer's or seller's indication, etc., and includes a solid printing layer.
When the release layer is an ink layer, the ink layer is arranged in contact with the resin base layer and plays a role of releasing the resin base layer by dissolution, peeling, or the like with a release liquid. The ink layer preferably contains a water-soluble resin or a compound having an acidic group, and a colorant. Moreover, the method for forming the ink layer is not limited, and it can be formed using a known method.
From the viewpoint of suitability for recoating, the ink layer preferably contains a compound containing an acidic group. In addition, from the viewpoint of printability, it is preferable to include a urethane resin having an acidic group, an acrylic resin having an acidic group, and a rosin-modified resin.
The water-soluble resin and the compound having an acidic group, the urethane resin having an acidic group, the acrylic resin having an acidic group, and the rosin-modified resin are the (water-soluble resin), ( Acidic group-containing compound), [Urethane resin having acidic group], [Acrylic resin having acidic group], and [Rosin-modified resin] can be cited.

(coloring agent)
The ink layer may be colored or colorless and contains known colorants used in printing inks and paints. Such coloring agents are not particularly limited, and in addition to inorganic pigments, organic pigments, and dyes, metal powders that impart metallic luster, near-infrared absorbing materials, and ultraviolet absorbing materials may be used.
Examples of inorganic pigments include colored 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 organic pigments, soluble azo pigments, insoluble azo pigments, azo chelate pigments, condensed azo pigments, copper phthalocyanine pigments, condensed polycyclic pigments and the like are preferably used.
It should be noted that the above pigments are not limited to these, and those listed in the generic names of the Color Index can be used as appropriate. Among them, when the removing liquid is a basic aqueous solution, a pigment having alkali resistance that does not dissolve in the basic aqueous solution is preferable. Preventing the elution of the pigment facilitates reuse of the aqueous base solution.
The alkali resistance of a pigment is generally estimated based on the skeleton or structure of the pigment. Pigments with alkali resistance include inorganic pigments, C.I. I. Pigment Blue 15, C.I. I. Pigment Yellow 83 can be mentioned.
When the pigment is titanium oxide, the content of titanium oxide in the ink layer is preferably 20-80 mass %, more preferably 30-75 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. % by mass.

(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 is introduced into the skeleton of the pigment, and the content of the pigment derivative is preferably 0.01 to 10% by mass, more preferably 0.05 to 6%, based on the mass of the colorant. % by mass, more preferably 0.1 to 4% by mass. When it is 0.01% by mass or more, the removability of the resin substrate layer is excellent, and when it is 10% by mass or less, reattachment of the ink layer can be suppressed.
The resin-type dispersant adsorbs to the colorant to stabilize the dispersion in printing ink or the like, 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 still more preferably 0.1 to 10% by mass, based on the mass of the colorant. . When the amount is 0.01% by mass or more, the releasability of the resin substrate layer is excellent, and when the amount is 30% by mass or less, the ink layer is excellent in water resistance.

The ink layer may contain a resin other than a water-soluble resin or a compound containing an acidic group.
Examples of such resins include fibrous materials such as nitrocellulose, cellulose acetate and propionate, chlorinated polypropylene, vinyl chloride-vinyl acetate copolymer, polyester, acrylic, urethane resin and acrylic urethane, Polyamide-based, polybutyral-based, cyclized rubber-based, and chlorinated rubber-based resins can be mentioned. These resins may be used individually by 1 type, and may use 2 or more types together.

The thickness of the ink layer is preferably 0.1 μm or more and 100 μm or less, more preferably 0.1 μm or more and 10 μm or less, and still more preferably 1 μm or more and 5 μm or less.

[Detachable adhesive layer]
When the release layer is an adhesive layer, the adhesive layer is placed in contact with the resin base layer and plays a role of releasing the resin base layer by dissolution, peeling, or the like with a release liquid. The adhesive layer preferably contains a compound having an acid group. Since 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 removed using the basic aqueous solution described above.
For the compound having an acidic group, the resin having an acidic group, and the low-molecular-weight compound having an acidic group, the description of (the compound having an acidic group) in the above section of [Desorption primer layer] can be used.
Moreover, the method for forming the adhesive layer is not limited, and it can be formed using a known method.

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

(polyester polyol)
The polyester polyol only needs to have an acidic group, and can be appropriately selected from known polyester polyols. By containing such a polyester polyol, when a basic aqueous solution is used as the removing liquid, the presence of an ester bond having a high affinity with a basic compound improves the removing property, which is preferable. Polyester polyols may be used alone or in combination of two or more.

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

The polyester polyol may be a polyester urethane polyol obtained by reacting the hydroxyl groups in the polyol with a polyisocyanate. The presence of urethane bonds in the polyester polyol 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. is mentioned.

Moreover, the polyester polyol may be an acid anhydride-modified product obtained by reacting the hydroxyl groups in the polyol with an acid anhydride. Thereby, a carboxy group, which is an acidic group, can be introduced into the polyester polyol.
Acid anhydrides include, for example, pyromellitic anhydride, mellitic anhydride, trimellitic anhydride, and trimellitic ester anhydride. Examples of trimellitate anhydrides include ethylene glycol bis-anhydro trimellitate and propylene glycol bis-anhydro trimellitate.

The acid value of the polyester polyol is preferably 5.0 mgKOH/g or more, more preferably 10.0 mgKOH/g or more. Moreover, 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 within the above range, the basic aqueous solution permeates and decomposes when the polyester polyol is brought into contact with a desorption liquid, which is a basic aqueous solution, thereby exhibiting better desorption properties.
When the adhesive contains a plurality of polyester polyols, the acid value of the entire polyester polyol can be obtained from the acid value of each polyester polyol and its mass ratio.

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

The polyester polyol component may be used in combination with a plurality of polyester polyol components in order to satisfy various physical properties required for the packaging material. Furthermore, a polyester polyol having a number average molecular weight of less than 3,000 may be included in order to improve adhesion to the substrate.
The content of the polyester polyol having a number average molecular weight of less than 3,000 is preferably 0 to 30% by weight, more preferably 0 to 20% by weight, based on the total weight of the polyester polyol. Retort resistance can be maintained as it is 30% by mass or less.

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

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

Aliphatic polyisocyanates include, for example, acyclic aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, and 1,2-butylene diisocyanate; 1,4-cyclohexane diisocyanate, Alicyclic diisocyanates such as 1,3-cyclohexane diisocyanate and 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (hereinafter referred to as isophorone diisocyanate); allophanate type, nurate type, biuret type derived from the above diisocyanates , adduct-type derivatives, or polyisocyanates such as complexes thereof;
The derivative is preferably a nurate type or an adduct type, more preferably an adduct type. As the aliphatic polyisocyanate, a polyisocyanate derived from hexamethylene diisocyanate (hereinafter also referred to as HDI) is preferable because it facilitates ensuring a good balance between detachability and laminate physical properties.

Examples of araliphatic polyisocyanates include 1,3- or 1,4-xylylene diisocyanate or mixtures thereof, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,3- or 1,4-bis( 1-isocyanate-1-methylethyl)benzene or mixtures thereof; allophanate type, nurate type, biuret type, adduct type derivatives derived from the above araliphatic diisocyanates, or complexes thereof Polyisocyanate;

(Other polyisocyanates)
The adhesive may contain other polyisocyanates other than the aliphatic polyisocyanate and the araliphatic polyisocyanate within a range that does not impair the effects of the present invention. Examples of such polyisocyanates include aromatic diisocyanates such as toluene diisocyanate and diphenylmethane diisocyanate; and polyisocyanates such as derivatives of the above diisocyanates and complexes thereof.

The mixing ratio of the polyol and polyisocyanate may be such that the molar ratio (NCO/OH) of the isocyanate groups of the polyisocyanate to the hydroxyl groups in the polyol is 0.3 to 10.0. It is preferably 0.3 to 7.0, more preferably 0.5 to 5.0.

(Other ingredients)
The adhesive layer contains silane coupling agents, phosphorus oxyacids or derivatives thereof, leveling agents, antifoaming agents, reaction accelerators, inorganic fillers (for example, silica, alumina, mica, talc, aluminum flakes, glass flakes, etc.). ), layered inorganic compounds, stabilizers (e.g., antioxidants, heat stabilizers, ultraviolet absorbers, hydrolysis inhibitors), rust inhibitors, thickeners, plasticizers, antistatic agents, lubricants, antiblocking agents, It may contain a coloring agent, a filler, a crystal nucleating agent, a catalyst for adjusting the curing reaction, and the like.

Polyethyleneimine and polybutadiene are preferably used in addition to the urethane-based adhesives described above as adhesives for extrusion.

[Polyethyleneimine]
Polyethyleneimine is a water-soluble polymer obtained by polymerizing ethyleneimine, and represents a substance that can be dissolved in water or alcohol. The polyethyleneimine is preferably a branched polyethyleneimine having a primary, secondary, or tertiary amino group in the molecule and a branched structure in the molecule, and known ones can be used. Moreover, one type may be used alone, or two or more types may be used in combination.

[Polybutadiene]
Polybutadiene may be a polymer having butadiene as a structural unit. As the butadiene, one derived from 1,2-polybutadiene is preferably used from the viewpoint of releasability. One type of polybutadiene may be used alone, or two or more types may be used in combination.

The thickness of the adhesive layer is preferably in the range of 1 to 10 μm, more preferably 1 to 6 μm when formed by dry lamination or non-solvent lamination, and 0.01 to 0.01 in the case of extrusion lamination. It is 1 μm, more preferably 0.03 to 0.9 μm.

[Metal Vapor Deposition Layer, Inorganic Oxide Vapor Deposition Layer]
A vapor deposited layer of a metal such as aluminum and a vapor deposited layer of an inorganic oxide such as alumina or silica are dissolved in a basic aqueous solution and desorbed. can.
The thickness of the vapor deposited metal layer and vapor deposited inorganic oxide layer is not particularly limited, but is preferably 0.001 to 5 μm.

<Resin substrate layer>
The resin substrate constituting the resin substrate layer is not particularly limited, but is preferably a sheet-like resin substrate, and examples thereof include conventionally known plastic films. The resin substrate layer may have a single-layer structure composed of one resin substrate, or may have a multilayer structure composed of a plurality of resin substrates. Further, when the resin substrate layer has a structure in which two resin substrates are laminated via an adhesive layer, the two resin substrates may be of the same type or of different types. good. Moreover, when it is the structure which laminated|stacked two resin base materials, co-extrusion molding or lamination extrusion molding may be carried out.

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

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; 6, nylon 6/ethylene-vinyl alcohol copolymer/nylon 6) and mixtures. Among them, those having mechanical strength and dimensional stability are preferable.
Although the thickness of the plastic film is not particularly limited, it is preferably 5 to 100 μm, more preferably 10 to 50 μm.

Also, a sealant base material can be used as the plastic film.
Examples of sealant base materials include polyethylene such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE), acid-modified polyethylene, polypropylene (PP), acid-modified polypropylene, and copolymerization. Examples include polypropylene, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid ester copolymer, ethylene-(meth)acrylic acid copolymer, and ionomer.
Although the thickness of the sealant base material is not particularly limited, it is preferably 10 to 200 μm, more preferably 15 to 150 μm, in consideration of processability to packaging materials, heat sealability, and the like. In addition, by providing the sealant base material with unevenness having a height difference of about several μm, slipperiness and tearability of the packaging material can be imparted.

It is important that the resin base material constituting the resin base material layer should not be softened at the time of shredding and block the cross section of the detachable layer. Therefore, the melting point of the resin base material is preferably 90° C. or higher, more preferably 100° C. or higher, and even more preferably 120° C. or higher.

Examples of methods for laminating at least two or more resin substrate layers together include known lamination methods such as a dry lamination method, a solventless lamination method, and an extrusion lamination method.
In the dorami lamination method and the non-solvent lamination method, the resin substrates can be laminated together via an adhesive layer, and an isocyanate adhesive is preferably used as the adhesive layer.
In the extrusion lamination method, known adhesives such as isocyanate adhesives, polybutadiene adhesives, polyethyleneimine adhesives, etc. can be used as the adhesive layer, or the melted resin is pressure-bonded without using adhesives. By doing so, it is also possible to laminate the resin base material layers.

<Structure of laminate>
The laminate in the present invention may have at least a resin substrate layer and a layer other than the resin substrate layer, and may further have another layer within a range that does not impair the effects of the present invention. . Layers that may be included include, for example, layers containing resins that do not fall under the release layer (e.g., ink layers, adhesive layers, primer layers, overcoat layers), metal foils such as aluminum foil, natural Examples include paper such as paper and synthetic paper.

Examples of the laminated body include the following configurations, and the laminate may have a configuration that satisfies two or more of the following configurations.
(1) It has a partial structure including 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 comprising 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. When there are two or more resin base layers, not all resin base layers have a release layer.
resin substrate layer/removable ink layer,
resin substrate layer/release primer layer/ink layer,
resin substrate layer/releasing ink layer/releasing adhesive layer/resin substrate layer,
resin substrate layer/removable primer layer/ink layer/removable adhesive layer/resin substrate layer,
resin substrate layer/ink layer/release adhesive layer/resin substrate layer,
resin substrate layer/release adhesive layer/resin substrate layer,
ink layer/resin substrate layer/release adhesive layer/resin substrate layer,
ink layer/resin substrate layer/adhesive layer/resin substrate layer/release adhesive layer/resin substrate layer,
Releasable ink layer/Resin substrate layer/Releasable adhesive layer/Resin substrate layer,
ink layer/removable primer layer/resin substrate layer/removable adhesive layer/resin substrate layer,
Resin substrate layer/Release primer layer/Ink layer/Release adhesive layer/Inorganic oxide deposition layer (Release layer)/Resin substrate layer,
Resin substrate layer/removable primer layer/ink layer/adhesive layer/inorganic oxide deposition layer (release layer)/resin substrate layer/removable adhesive layer/resin substrate layer.

<Laminate Separation and Collection Method>
The separation and recovery method of the present invention includes the following steps.
(1) crushing at least a laminate having a resin substrate layer and a release layer;
(2) A desorption step of contacting the fluff with a desorption liquid to detach the detachable layer (3) A collection step of collecting the separated resin base material

[Fluff]
In the shredding step, the average size of the fluff is 10 mm or more,
The standard deviation of the fluff size distribution is 10 mm or more,
The laminate is shredded so that the fluff that does not pass through a 3 mm sieve is 60% by weight or more of the total fluff.
Here, the average size of the fluff and the standard deviation of the size distribution of the fluff can be measured, for example, by a sieving device.

The average size of the fluff is 10 mm or more, preferably 10-30 mm, more preferably 12-25 mm. Within the above range, the time required for the desorbing liquid to permeate from the end face to the center of the shredded material is shortened, and separation and recovery can be performed efficiently. Physical properties are also improved.
The standard deviation of the fluff size distribution is 10 mm or more, preferably 10-20 mm, more preferably 12-16 mm. Within the above range, the bulk specific gravity of the fluff is higher than that of fluff having a standard deviation of 10 mm or less, so that a large amount of fluff can be desorbed per batch.
Fluff that does not pass through a 3 mm sieve is 60% by weight or more, preferably 65% by weight or more, and more preferably 70% by weight or more of the entire fluff. In the actual process, the step of passing through a 3 mm sieve is not necessarily required.

In order for the standard deviation of the size distribution of the fluff to be 10 mm or more, for example, two or more lots with different average sizes of the fluff are separately prepared and mixed before the separation step, and a screen is used at the time of crushing. Examples include a method of increasing the size, a method of increasing the flow rate of water in wet crushing, and a method of reducing the amount of laminate to be fed into the crusher. When a circulation wet crusher is used, the standard deviation of the resulting fluff size distribution tends to increase by shortening the residence time of the laminate in the crushing section.

Examples of the shredding method include a method using a cutter mill (rotary cutter), and examples of a shredding device using a cutter mill include MF45-700WRS manufactured by Tanaka and PF-2000 manufactured by Nippon Seam. .

An example of the shredding process in the present invention is shown below.
The layered product is fed from the layered product inlet of the cutting device, and shredded to a predetermined size or less by the shredding section together with water supplied from the water inlet. A known structure can be used for the shredded portion. In the shredding section, it is preferable to use a rotary cutter that shreds using a shearing force.

In the shredding step, the water may contain a detergent or the like in order to clean dirt such as the contents adhering to the laminate. In addition, the water used in the shredding step may contain components of the desorbed liquid. The water used in the shredding step can promote the separation in the separation step by including the components of the cleaning agent and the desorbing liquid.

However, in the present invention, the shredding step and the separation step are performed separately from the viewpoint of preventing impurities such as ink pieces from adhering and accumulating on the resin base material. It is preferable that the components of the cleaning agent and the removing liquid that can be contained in the water used in the above range are such that separation of the resin substrate layer does not proceed.

When shredding progresses and the size of the shredded material falls below a certain size, it passes through the screen provided below the shredding section by its own weight together with water. A screen refers to something that has the role of a filter that allows objects of a certain size or smaller to pass through, and is sometimes called a filter or a grid. The shape of the screen may be circular, diamond-shaped, fan-shaped, or the like, and can be appropriately selected according to the hardness and thickness of the shredded material.

The long side of the shredded material can be adjusted according to the size of the screen to be used. For example, if the shape of the screen is circular, use a screen with a diameter of 15 mm to control the average fluff size to about 10 mm. However, depending on the pumping conditions, it is produced in a state in which the particles larger and smaller than the screen size are appropriately mixed.

The mass of water used in the shredding step is preferably 10 to 100 times, more preferably 15 to 80 times, still more preferably 20 to 60 times the mass of the laminate.
Within the above range, fluff with an appropriate size distribution can be obtained. In addition, since the amount of water for cooling the laminated body is sufficient and the inflow and outflow of water to the shredded portion are repeated constantly, local temperature rise in the shredded portion due to shearing is suppressed. As a result, fusion bonding and softening of the resin base material of the laminate can be suppressed.
In addition, when the amount of water is within the above range, not only the shredded material but also unnecessary components such as fine ink fragments and adhesive fragments generated during shredding easily pass through the screen described above, and shredding. It is possible to prevent stagnation of the laminate in the part and screen clogging due to unnecessary components.
As a result, the laminate does not remain excessively in the shredded portion, and generation of fine pieces due to fusion of the resin base material and excessive shredding can be suppressed.
The mass of water used in the shredding step represents the mass of water put into the shredding device for one minute, and the mass of the laminate is the mass of the laminate put into the shredding device for one minute. represents

In order to efficiently perform the shredding step, the separation and recovery method of the present invention has a sorting step of sorting the laminate in the present invention having at least a resin base layer and a detachable layer before the shredding step. may be
In addition, before the shredding process, a rough shredding process may be included in which the laminate is shredded to a size that is easy to put into a shredding device. Examples of equipment used in the rough crushing step include a hydraulic cutting machine.

After the shredding process, a classification process may be further included. The classification method is not particularly limited, but includes classification by screen, classification by centrifugal separation, a combination thereof, and the like, and known classifiers can be used.

The diameter of the screen used for classification by the screen is preferably 5 to 30 mm, and this range is suitable for obtaining 60% by mass or more of fluff that does not pass through a 3 mm sieve.

The water used in the shredding step may be reused after undergoing an impurity removal process.

(Desorption process, deinking process)
The deinking step is a step of immersing the obtained shredded material (fluff) in a desorption liquid to separate the resin substrate layer from the other layers, and can be appropriately selected from known methods.
The content of the fluff when desorbing the fluff from the laminate in the desorbing liquid is usually 0.1 to 40% by mass with respect to the total mass of the desorbing liquid from the viewpoint of production efficiency.

(desorption liquid)
The release liquid may be any liquid that allows the resin substrate layer to be released by swelling and dissolving the release layer. Examples of such desorption liquids include water, basic aqueous solutions, acidic aqueous solutions, and fluorine-based solvents. Water or an aqueous solution is preferable from the viewpoint of the environment and the maintenance of the properties of the recycled material using the recovered resin base material. Further, a basic aqueous solution containing a basic compound is more preferable, since both the layer containing a compound having an acidic group and the layer containing a water-soluble resin can be eliminated. These desorbed liquids may be heated.

[Basic compound]
Basic compounds are not particularly limited, and examples include sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH) ₂ ), ammonia, barium hydroxide (Ba(OH) ₂ ), carbonate Sodium _{( Na2CO3} ) is 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 still more preferably 3 to 15% by mass, based on the mass of the basic aqueous solution. Range. Within the above range, the basic aqueous solution can maintain sufficient basicity to dissolve or swell the detachable layer to detach the detachable layer and recover the resin substrate layer.

[Surfactant, etc.]
Additives such as a surfactant and an antifoaming agent may be added to the removing liquid. In particular, the addition of surfactants and/or defoamers is preferred.

[Surfactant]
The desorption liquid preferably contains water and a surfactant. A surfactant mainly plays a role of improving the detachability of the detachable layer. This is probably because the action of the surfactant makes it easier for the stripping liquid to permeate into layers other than the resin base layer, such as the primer layer, the printed layer, and the adhesive layer, thereby promoting the strippability. . In addition, when the amount of the laminate relative to the desorbing liquid is increased in the separation and recovery, the laminate and the separated base material tend to curl with the desorbed ink pieces involved, and even if they are immersed in the desorbing liquid. However, it is difficult to cleanly remove ink fragments and the like caught in the curl. However, since the desorption liquid contains a surfactant, the surfactant is adsorbed on the surfaces of the laminate and the separated base material, thereby suppressing curling. As a result, detachability is improved and reattachment can be suppressed.
Furthermore, when the stripping liquid contains a surfactant, it is possible to strip the printed layer in contact with the plastic substrate without the primer layer.

Types of surfactants include, for example, nonionic, anionic, cationic, and amphoteric surfactants, and suitable types and blending amounts can be appropriately selected and used according to required properties. From the viewpoint of releasability and foamability, it is preferably at least one selected from the group consisting of anionic surfactants and nonionic surfactants.
Further, the surfactant has a structure to which an alkylene oxide (hereinafter also referred to as AO) is added, so that deinking property and reattachment property are improved, which is preferable.

(Nonionic surfactant)
Although the nonionic surfactant is not particularly limited, it is preferably an alkylene oxide adduct to which alkylene oxide is added. More preferred are compounds obtained by adding alkylene oxide to alcohols having active hydrogen, compounds obtained by adding alkylene oxide to amines, or compounds obtained by adding alkylene oxide to fatty acids. The addition may be either random addition or block addition. Also, the carbon number of the alkylene oxide is preferably 2 to 4 carbon atoms.
More preferred nonionic surfactants are alcohol-based nonionic surfactants obtained by adding an alkylene oxide having 2 to 4 carbon atoms to an alcohol.

[Alcohol-based nonionic surfactant]
Examples of alcohol-based nonionic surfactants include alkylene oxide adducts of primary or secondary alcohols having a total carbon number of 8 to 24, or alkylene oxide adducts of alkylphenols having a total carbon number of 8 to 12. be done. The primary or secondary alcohol having a total carbon number of 8 to 24 may be either saturated or unsaturated.
Examples of primary or secondary alcohols having a total carbon number of 8 to 24 include lauryl alcohol, stearyl alcohol, oleyl alcohol, dodecyl alcohol, arachidyl alcohol, behenyl alcohol, lignoceryl alcohol, and myristyl alcohol.
Examples of the alkylene oxide to be added to the alcohol include ethylene oxide, propylene oxide and butylene oxide, and ethylene oxide is preferably essential. The number of moles of alkylene oxide to be added is preferably 1 to 100 mol, more preferably 2 to 50 mol, per 1 mol of alcohol or alkylphenol. It is preferable that it is in the above range because it is particularly excellent in releasability.

[Fatty acid-based nonionic surfactant]
The structure of the fatty acid-based nonionic surfactant is not particularly limited. Examples include oils and fats composed of esters of higher fatty acids and glycerin, and alkylene oxide adducts of mixtures of the above oils and fats and 2 to 10 polyhydric alcohols. The higher fatty acid having 10 to 24 total carbon atoms may be either saturated or unsaturated.
Examples of the higher fatty acids having 10 to 24 carbon atoms in total include saturated higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid; palmitoleic acid, oleic acid, elaidic acid, linoleic acid, unsaturated higher fatty acids such as linolenic acid, erucic acid and ricinoleic acid; Dihydric to decahydric polyhydric alcohols include ethylene glycol, propylene glycol, glycerin, polyglycerin, sorbitol, sorbitan, sucrose and the like. The type and number of moles of alkylene oxide to be added are the same as those described in the section [Alcoholic Nonionic Surfactant] above.

[Amine-based nonionic surfactant]
Amine-based nonionic surfactants include AO adducts of saturated or unsaturated primary or secondary amines having a total carbon number of 8 to 36. Amines include 2-ethylhexylamine, di-2-ethylhexylamine, laurylamine, dilaurylamine, tetradecylamine, ditetradecylamine, hexadecylamine, dihexadecylamine, stearylamine, distearylamine, oleylamine, di and oleylamine. Moreover, the kind of AO and the number of added moles are the same as above.

(Anionic surfactant)
The anionic surfactant is preferably a non-soap surfactant, such as a sulfonate anionic surfactant, a sulfate ester anionic surfactant, a carboxylic acid anionic surfactant, a phosphate ester anionic surfactant. active agents.

[Sulfonic acid-based anionic surfactant]
Examples of the sulfonic acid anionic surfactant include alkylsulfonic acid, alkylbenzenesulfonic acid, alkylnaphthalenesulfonic acid, alkyldiphenyletherdisulfonic acid, alkylmethyltaurine, sulfosuccinic acid diester, alkylene oxide adduct of sulfonic acid, and these. salt of Specific examples include hexanesulfonic acid, octanesulfonic acid, decanesulfonic acid, dodecanesulfonic acid, toluenesulfonic acid, cumenesulfonic acid, octylbenzenesulfonic acid, dodecylbenzenesulfonic acid, dinitrobenzenesulfonic acid, and lauryldodecylphenyl ether disulfone. An acid or the like can be used.

[Sulfuric Acid Ester-Based Anionic Surfactant]
Examples of the above-mentioned sulfate ester-based anionic surfactants include sulfate esters (alkyl ether sulfate esters), alkylene oxide adducts of sulfate esters, and salts thereof. Specific examples include lauryl sulfuric acid, myristyl sulfuric acid, polyoxyethylene lauryl ether sulfuric acid, and the like.

[Carboxylic acid-based anionic surfactant]
Examples of the carboxylic acid-based anionic surfactants include alkylcarboxylic acids, alkylbenzenecarboxylic acids, alkylene oxide adducts of carboxylic acids, and salts thereof. Specific examples include lauric acid, myristic acid, palmitic acid, stearic acid, polyoxyethylene lauryl ether acetic acid, and polyoxyethylene tridecyl ether acetic acid.

[Phosphate Ester Anionic Surfactant]
Examples of the phosphate ester-based anionic surfactants include phosphate esters (alkyl ether phosphate esters), alkylene oxide adducts of phosphate esters, and salts thereof. Specific examples include octyl phosphate, lauryl phosphate, tridecyl phosphate, myristyl phosphate, cetyl phosphate, stearyl phosphate, polyoxyethylene octyl ether phosphate, and polyoxyethylene lauryl ether phosphate. etc. can be used.

The anionic surfactant preferably has an alkyl group of 2 to 24 carbon atoms or an alkenyl group of 2 to 24 carbon atoms, more preferably an alkyl group of 8 to 18 carbon atoms. The alkyl group or alkenyl group may be linear or branched.
When the anionic surfactant is an alkylene oxide adduct, examples of the alkylene oxide include ethylene oxide, propylene oxide and butylene oxide, with ethylene oxide being preferred. The number of moles of alkylene oxide to be added is preferably 1 to 12 mol, more preferably 1 to 8 mol, per 1 mol of alcohol or alkylphenol. It is preferable that it is in the above range because it is particularly excellent in releasability.

Examples of salts constituting the above-mentioned anionic surfactants include metal salts of sodium, potassium, magnesium, calcium and the like. These salts may be used individually by 1 type, and may be used in combination of 2 or more type.
Among them, the anionic surfactant is preferably a sulfonate type or a phosphate type, more preferably an alkyl sulfonate or a polyoxyalkylene alkyl ether sulfonate, from the viewpoint of desorption and reattachment properties. , polyoxyalkylene alkyl ether phosphate, and the like.

(Cationic surfactant)
Examples of cationic surfactants include alkylamine salts and quaternary ammonium salts. Specifically, stearylamine acetate, trimethylyac ammonium chloride, trimethyl tallow ammonium chloride, dimethyldioleyl ammonium chloride, methyloleyl diethanol chloride, tetramethylammonium chloride, laurylpyridinium chloride, laurylpyridinium bromide, laurylpyridinium disulfate, cetylpyridinium bromide. , 4-alkylmercaptopyridine, poly(vinylpyridine)-dodecyl bromide, dodecylbenzyltriethylammonium chloride and the like can be used.

(Amphoteric surfactant)
Examples of amphoteric surfactants include betaine lauryldimethylaminoacetate, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, betaine coconut fatty acid amidopropyldimethylaminoacetate, polyoctylpolyaminoethylglycine, and imidazoline. derivatives.

These surfactants may be used alone or in combination of two or more. The content of the surfactant in the desorbed liquid is preferably in the range of 0.001 to 10% by mass, more preferably in the range of 0.005 to 7% by mass, based on the mass of the desorbed liquid. , more preferably 0.03 to 5% by mass, still more preferably 0.05 to 3% by mass. When the amount is 0.001% by mass or more, the deinking property is excellent, and the median diameter of the separated print layer components can be easily controlled to 1 μm or more.

(Temperature of desorption solution, etc.)
The temperature of the stripping liquid when the shredded material is immersed is preferably 25 to 120°C, more preferably 30 to 120°C, and particularly preferably 30 to 80°C. The immersion time in the desorbing solution is preferably 1 minute to 24 hours, more preferably 1 minute to 12 hours, and preferably 1 minute to 6 hours. The amount of the desorption liquid used is preferably 5 to 100,000 times, more preferably 10 to 10,000 times the mass of the shredded material. It is preferable to stir or circulate the liquid. The rotation speed is preferably 80-5000 rpm, more preferably 80-4000 rpm.

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

[Step (3)] Recovery step Step (3) is a step of recovering the resin base material 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 cartridge filters, belt filters, drum filters, dyna filters, rotary filters, meshes, screens, drum screens, slurry screeners, auto strainers, extrusion centrifuges, continuous centrifuges, and filtration systems. Any separation means including a filter may be included, and a mesh conveyor capable of carrying while filtering with a filter may be used.

In the step (3), a step of removing components other than the resin base material layer, such as ink and adhesive separated from the laminate, may be provided before recovering the resin base material. Components such as the ink and adhesive are finely divided by the shearing force in step (2), so the size of the filter is adjusted using the difference in size from the shredded material in step (1). By doing so, the resin base material can be recovered while removing fine pieces of the ink or adhesive component adhering to the resin base material.
After recovering the resin substrate and removing components other than the resin substrate layer, such as ink and adhesive, the detached liquid may be reused in step (2).

The step (3) may include a step of sorting the resin species of the resin base material (sorting step). Examples of the sorting step include a gravity sorting method using a liquid, an air sorting method, and a near-infrared sorting method, and from the viewpoint of productivity, the gravity sorting method using a liquid is preferable.
In the specific gravity sorting method using a liquid, for example, when water is used as the specific gravity liquid, a resin base material having a specific gravity lighter than water such as polyethylene and polypropylene and a resin base material having a specific gravity heavier than water such as polyester, nylon, and cellophane can be selected. As the specific gravity liquid, an organic solvent, an aqueous solution of a metal salt compound, or the like may be blended alone or mixed to appropriately adjust the specific gravity. Such gravity sorting can also be performed multiple times.
The collected resin base material is subjected to treatment such as dehydration treatment and drying treatment as necessary, and then reused.

<Reuse of resin base material>
A molding material can be produced by melt-kneading the resin base material recovered by the separation and recovery method described above.
In the melt-kneading process, various additives are added as necessary, and after mixing with a Henschel mixer, tumbler, disper, etc., kneaders, roll mills, super mixers, Henschel mixers, Sugi mixers, vertical granulators, high-speed mixers, Mixing and dispersion using a batch kneader such as a furmatrix, ball mill, steel mill, sand mill, vibration mill, attritor, Banbury mixer, twin-screw extruder, single-screw extruder, rotor-type twin-screw kneader, etc. refers to doing As a result, a recycled resin, which is a resin composition, is obtained. The shape of the recycled resin is not particularly limited, and may be in the form of pellets, powder, granules, or beads. The melt-kneading step preferably uses a twin-screw extruder.

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 polyethylene resin or polypropylene resin and a colorant kneaded can be used. The thermoplastic resin contained in the masterbatch may be used alone or in combination of two or more.
The masterbatch contains alkali metal, alkaline earth metal, or zinc metallic soap, hydrotalcite, nonionic surfactant, cationic surfactant, anionic surfactant, amphoteric surfactant, as long as it does not impair the effects of the present invention. Surfactants, antistatic agents, flame retardants such as halogen-based, phosphorus-based or metal oxides, lubricants such as ethylenebisalkylamide, antioxidants, ultraviolet absorbers and fillers may be contained.

A molded article can be obtained by heat-molding the molding material obtained as described above. The thermoforming method is not particularly limited, and examples thereof include injection molding, extrusion molding, blow molding, and compression molding.
The molding material produced using the resin base material recovered by the separation and recovery method of the present invention has excellent releasability because the cross section of the shredded material is not blocked, so that the adhered components are suppressed and the quality is high. It can be used in various fields such as home electric appliances, stationery, automobile parts, toys, sporting goods, medical materials, and building and construction materials.

EXAMPLES The present invention will be described in detail below with reference to Examples, but the present invention is not limited to these Examples. In addition, "parts" and "%" in the present invention represent "mass parts" and "mass%" unless otherwise specified.

<Production of primer resin>
[Synthesis Example 1] (Polyurethane resin P1 having an acidic group)
While introducing nitrogen gas in a reactor equipped with a reflux condenser, a dropping funnel, a gas inlet tube, a stirrer, and a thermometer, PPA (consisting of a polycondensate of propylene glycol and adipic acid, having a number average molecular weight of 2, 000 polyester polyol), 135.7 parts of PPG (a polyether polyol having a number average molecular weight of 2,000 consisting of polypropylene glycol), 28.3 parts of DMPA (2,2-dimethylolpropanoic acid), IPDI 105.7 parts of (isophorone diisocyanate) and 200 parts of NPAC (n-propyl acetate) were charged and reacted at 90° C. for 5 hours to obtain a urethane prepolymer solution having terminal isocyanate groups.
Then, a mixture of 16.7 parts of AEA (2-(2-aminoethylamino) ethanol) and 350 parts of IPA (isopropyl alcohol) was added dropwise over 60 minutes at room temperature, followed by reaction at 70° C. for 3 hours. to obtain a polyurethane resin solution.
NPAC was added to the obtained polyurethane resin solution to adjust the solid content to obtain a solution of polyurethane resin P1 having an acidic group with a solid content concentration of 30% and an acid value of 39.3 mgKOH/g.
The acid value was measured according to the method described in JISK0070 (1992).

[Production Example 1-1] (Primer Composition AC1)
87 parts of a polyurethane resin P1 solution having an acidic group, 5 parts of EA (ethyl acetate), 5 parts of IPA, and 3 parts of silica particles (P-73 manufactured by Mizusawa Chemical Co., Ltd.: hydrophilic silica particles having an average particle diameter of 3.8 μm) were dispersed. and mixed with stirring to obtain a primer composition AC1.

<Adhesive AD1>
<Production of polyol used for adhesive>
[Synthesis Example 2-1] (polyester polyol A1)
124 parts of ethylene glycol, 212 parts of neopentyl glycol, 368 parts of 1,6-hexanediol, 645 parts of isophthalic acid and adipine were placed in a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping tank and nitrogen gas inlet tube. 36 parts of acid and 265 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 became 5 or less, the pressure was gradually reduced, and the deglycol reaction was performed at 1 mmHg or less for 5 hours to obtain a polyester polyol. After that, 35 parts of isophorone diisocyanate was gradually added and reacted at 150° C. for about 2 hours to obtain a polyester polyurethane polyol. 12.0 parts of ethylene glycol bis-anhydrotrimellitate was added to 100 parts of this polyester polyurethane polyol, reacted at 180° C. for about 2 hours, and then diluted with ethyl acetate until the solid content concentration reached 50%. A solution of partially acid-modified polyester polyol A1 having an average molecular weight of 9,000 and an acid value of 30.3 mgKOH/g was obtained.

[Synthesis Example 2-2] (polyester polyol A2)
58 parts of ethylene glycol, 412 parts of diethylene glycol, 343 parts of neopentyl glycol, 517 parts of isophthalic acid, and 393 parts of adipic acid are charged into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping tank and nitrogen gas inlet tube. , the temperature was raised to 250° C. with 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 became 5 or less, the pressure was gradually reduced, and the deglycol reaction was performed at 1 mmHg or less for 5 hours to obtain a polyester polyol. 4.0 parts of trimellitic anhydride was added to 100 parts of this polyester polyol, reacted at 180° C. for about 2 hours, and then diluted with ethyl acetate to a solid content concentration of 50%, resulting in a number average molecular weight of 2,000. A solution of partially acid-modified polyester polyol A2 having an acid value of 23.5 mgKOH/g was obtained.

<Adjustment of polyisocyanate>
[Preparation Example 1-2] (Polyisocyanate B1)
Coronate 2785 (biuret-type polyisocyanate derived from hexamethylene diisocyanate, manufactured by Tosoh Corporation) was diluted with ethyl acetate to adjust the solid content concentration to 50% and NCO% = 9.6%, and a solution of polyisocyanate B1 was prepared. Obtained.

<Manufacture of adhesive>
[Production Example 1-3] (Adhesive AD1)
90 parts of the polyester polyol A1 solution, 10 parts of the polyester polyol A2 solution, and 8 parts of the polyisocyanate B1 solution were blended, and EA was added to prepare an adhesive solution having a solid concentration of 30%. <Production of laminate>
A method for manufacturing a laminate will be described below. The printing ink and the primer composition were each prepared using a mixed solvent of EA/IPA (mass ratio: 70/30) so that the viscosity would be 15 seconds (25°C, Zahn cup #3 (manufactured by Rigosha)). was used after diluting to

[Production Example 2-1] (Laminate L1)
Diluted primer (AC1) and printing ink (INK1) were printed in this order on OPP (corona-treated oriented polypropylene film, thickness 20 μm) using a gravure printing machine equipped with a gravure plate having a plate depth of 30 μm, After drying at 50° C., a laminate L1 having a structure of OPP/AC1/INK1 was obtained.

[Production Example 2-2] (Laminate L2)
Adhesive AD1 was coated on OPP (corona-treated oriented polypropylene film, thickness 20 μm) using a dry laminator so that the film thickness after drying was about 3 μm, dried, and then CPP (non-oriented polypropylene film, thickness 50 μm). to obtain a laminate L2 having a configuration of OPP/INK1/AD1/CPP.

[Production Examples 2-3 to 6] (Laminates L3 to 6)
A laminate L2-4 was obtained in the same manner as in Production Example 2-1 except that layers other than the substrate and the resin substrate layer were changed to those shown in Table 1. In addition, AC1, INK1, and INK2 were printed by the same method as in Production Example 2-1, and AD1 and AD2 were applied and dried by the same method as in Production Example 2-2. L2-5-6 were obtained.
The printing inks, adhesives and substrates used are as follows.
INK1: Toyo Ink General-Purpose Laminating Ink “LP Bio SX R39 Indigo”
INK2: Toyo Ink general-purpose surface printing ink “PANNECO AM 39 indigo”
AD1: Adhesive AD1 above
AD2: Toyo-Morton's ether-based dry lamination adhesive "TOMOFLEX TM-320 / isocyanate-based curing agent CAT-13B"
(Mixing ratio TM-320: CAT-13B = 100: 75) OPP: corona-treated oriented polypropylene film, thickness 20 μm
CPP: unstretched polypropylene film thickness 50 μm
Anti-fog OPP: Anti-fog treated oriented polypropylene film, thickness 20 μm
NY: stretched nylon film, thickness 15 μm
VMCPP: Aluminized unstretched polypropylene film, thickness 25 μm

<Crushing the laminate and creating fluff>
[Fluff Example 3-1] (Fluff F1)
As a wet crusher, PFS-40 type manufactured by Nippon Seam Co., Ltd. (a vertical shredder equipped with a cutter mill and a circular screen whose diameter is arbitrarily controlled) was used to wet crush the laminate. The laminate L1 was charged from the hopper, and the crushing step was performed while water was introduced from the water inlet. When shredding progresses and the fluff size becomes less than a certain size, it passes through the screen provided at the bottom of the shredding section by its own weight together with water. The long side of the fluff can be adjusted according to the size of the screen used, and by using a circular screen with a diameter of 15 mm, a fluff with an average long side of 10 mm was obtained.
Next, the layered product was washed and filtered using SW-408 model (a washing and filtering device having a circular screen) manufactured by Nippon Seam Co., Ltd. as a washing and filtering device. By using a circular screen with a diameter of 3 mm, a certain percentage of fluff with a long side of 3 mm or less is removed, and the average size of the long side is 10 mm, the weight of fluff with 3 mm or less is 30%, and the standard deviation of the long side is 10 mm. Got fluff F1.
(Residence time)
The time from when the film is put into the crusher until it passes through the crusher screen.
(Fluff input amount)
The weight of the film put in per unit time.

[Fluff Examples 3-2 to 12, Fluff Comparative Production Examples 3-14, 3-16] (Fluff F2 to 12, F14, F16)
Fluff F2 to F12, F14, and F16 were obtained by using the same equipment and method as in Fluff Production Example 3-1, changing the laminate, screen size, residence time, and fluff input amount shown in Table 2.

[Fluff Example 3-13] (Fluff F13)
The laminate was cut into 5 mm and 35 mm sizes, and the same number of pieces were mixed to obtain fluff F13.

[Fluff Example 3-15] (Fluff F15)
The laminate was cut into a size of 20 mm to obtain fluff F15.

<Production of desorbed liquid>
[Production Example 4-1] (Elimination liquid A1)
97.5 parts of water, 2 parts of sodium hydroxide, and 0.5% by weight of polyoxyethylene stearyl ether (polyoxyethylene addition number: 12) were blended and stirred with a disper to obtain an elimination liquid A1.

<Separation and recovery of laminate>
[Example 1]
500 g of desorption liquid A1 and 50 g of laminate L1 were placed in a 1000 mL stainless steel beaker and stirred at 70° C. and 2000 rpm. The following evaluations were performed on the state of separation and collection of the laminate.

[Examples 2 to 13, Comparative Examples 1 to 3]
In addition, the recycled material was evaluated in the same manner as in Example 1, except that the fluff was changed to the content shown in Table 3. Table 3 shows the results.

(Production of recycled film and evaluation of recycled resin coloring)
After 2 hours from the start of stirring, the detached OPP base material and CPP base material were recovered, extruded at 200° C. with a single screw extruder, and pelletized to obtain recycled resin pellets. The recycled resin was extruded at 200° C. using a T-die film molding machine to produce a recycled film having a thickness of 50 μm.
The color values L*x, a*x, and b*x of the recycled film were measured with a spectrophotometer (X-rite eXact, manufactured by X-rite). The OPP base material before printing was similarly subjected to the pelletizing process to prepare a recycled film having a thickness of 50 μm, and the color difference ΔE was obtained by the following formula.
(Formula) ΔE = ((L*x-L*y) ² + (a*x-a*y) ² + (b*x-b*y) ² ) ^1/2
Evaluation criteria are as follows. Evaluation C or higher is the usable range.
A (excellent): ΔE is less than 3 B (good): ΔE is 3 or more and less than 10 C (acceptable): ΔE is 10 or more and less than 20 D (improper): other than A to C

(Recycled resin physical property evaluation)
The melt mass flow rate (MFR) of the recycled film was measured as a physical property value of the recycled film prepared above. A mixed film obtained by mixing the OPP base material and the CPP base material before printing at a weight ratio of 1:1 was similarly subjected to the pelletizing process to prepare a recycled film, and the MFR was measured.
Taking the MFR of the mixture of the OPP base material and the CPP base material before printing as 100%, the MFR increase rate of the obtained recycled film was evaluated according to the following criteria. Evaluation or higher is the usable range. The MFR was measured according to JIS K-7210.
A (excellent): less than +50% B (good): +50% or more and less than 100% C (acceptable): +100% or more and less than 200% D (improper): +200% or more

[Example 14]
As the laminate L7, a laminate having a configuration of INK1/AC1/OPP/AD2/CPP was produced in the same manner as in Production Examples 2-1 and 2-2. The recycled resin contained OPP, AD2, and CPP, and the recycled resin coloring evaluation was A (excellent).

In Comparative Examples 1 and 3, the average size of the fluff was less than 10 mm, and the percentage by mass of the fluff that did not pass through the 3 mm sieve was small, so the coloring of the recycled resin could not be evaluated. In addition, in Comparative Example 2, in the step of stirring the fluff in the desorption liquid, the fluff was not sufficiently immersed in the desorption liquid due to its bulkiness, resulting in significant coloration of the recycled base material and deterioration of physical properties. became.
From the above evaluation results, it was shown that by using the fluff of the present invention, it is possible to process a large amount of fluff at once without degrading the mechanical properties in the production of recycled materials.

Claims (4)

A shredding step of crushing at least a laminate having a resin substrate layer and a layer other than the resin substrate layer to make the laminate fluffy,
a desorption step of detaching a layer other than the resin base layer by contacting the fluff with a desorption liquid;
Also, a method for recovering a resin base material including a recovering step of recovering the detached resin base material,
The shredding step includes wet crushing with a cutter mill, the average size of the fluff after crushing is 10 mm or more, and
A method for recovering a resin substrate, comprising cutting such that the standard deviation of the fluff size distribution is 10 mm or more, and the fluff that does not pass through a 3 mm sieve accounts for 60% by weight or more of the entire laminate. 2. The method for recovering a resin substrate according to claim 1, wherein the resin substrate layer contains an olefin resin. 3. The method for recovering a resin base material according to claim 1, wherein the fluff has an average size of 10 mm to 30 mm. 4. The method for recovering a resin base material according to claim 3, wherein the standard deviation of the fluff size distribution is 10 mm to 20 mm.