JP7401015B1 - Separation and recovery method of plastic base materials - Google Patents

Abstract

[Problem] An object of the present invention is to provide a method for highly efficiently separating and recovering a laminate suitable for plastic recycling, which has excellent removability of a coating layer and further suppresses redeposition of desorbed coating layer components. It is about providing. Another object of the present invention is to provide a method for producing a high-quality molded article obtained by heat-molding a recovered plastic base material. [Solution] A step of crushing a laminate including at least a plastic base material and a coating layer in contact with the plastic base material into fluffs having an average size of 5 mm or less, and converting the crushed fluffs into a desorption liquid. A method for separating and recovering a laminate, the method comprising the step of contacting the plastic substrate to detach the coating layer from the plastic substrate, wherein the content of the laminate is 10% by mass based on the total mass of the detachment liquid. The above is the method for separating and recovering a laminate. [Selection diagram] None

Description

The present invention relates to a method for separating and recovering a plastic substrate from a laminate including at least a plastic substrate layer and a coating layer.

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

Examples of the above-mentioned plastic products include multi-layered food packaging packages using plastic films. In such food packaging packages, the film base material is polyester base material, nylon base material (NY), polypropylene base material ( Various plastic substrates are used, such as PP) and polyethylene substrates (PE). These film base materials are printed with printing ink, bonded to other film base materials or hot-melt resin base materials via an adhesive, etc., and then cut and heat-sealed to form a package. However, such multi-layered food packaging packages contain a mixture of a plurality of different types of materials that are not compatible with each other, so there is a problem that material recycling cannot be performed as is.

Regarding the material recycling of such multi-layered packaging materials, for example, Patent Documents 1 and 2 disclose that by treating a laminate including a release layer containing a polyurethane resin having a predetermined acid value with an alkaline aqueous solution, Techniques have been disclosed for removing printed layers not only from surface-printed laminates but also from multi-layered laminates. Patent Document 3 discloses a technique for removing an adhesive layer from a multi-layered laminate by treating the laminate including a polyester polyol adhesive having a predetermined acid value with an alkaline aqueous solution. .

JP2020-090627A JP2021-098294A JP2020-084130A

In the present invention, "fluff" refers to at least a sheet etc. that has been shredded or crushed into a size that allows the process to be carried out, and the sheet etc. is at least a plastic base material and a plastic base material. It is a laminate including a coating layer in contact with the coating layer. In particular, it refers to a fluff used for the purpose of removing a coating layer and recovering a highly pure plastic base material by contacting it with a desorption liquid. The plastic substrate may have a single layer or multiple layers. When the plastic base material has a plurality of layers, the plastic base material to be recovered may have some or all of the plurality of layers separated, or may remain as a plurality of layers.
Since the fluff used in the desorption process described in Patent Documents 1 to 3 is large in size, it is generally difficult to increase the throughput of the fluff with respect to the desorption liquid in order to improve treatment efficiency. In the immersion method, problems arise such as if the amount exceeds a certain level, the desorbing liquid cannot be immersed in the liquid and overflows, and the motor is under pressure and cannot be stirred. Moreover, since the fluff size is large, the desorption time becomes long, and the problem arises that the coating layer re-adheres to the substrate after desorption. Here, "re-deposition" means that the coating layer that has been detached from the base material or the coating layer that has detached from the base material and is not in direct contact with the plastic base material is finely dispersed by stirring and re-attached to the base material. This causes discoloration of the recovered base material and deterioration of the properties of the recycled material. In other words, the molding material obtained by recycling the plastic base material to which the detached coating layer has been reattached as described above (hereinafter also referred to as recycled material or recycled base material) will not deteriorate in appearance due to coloring or have physical properties. cause a decline.

Therefore, an object of the present invention is to provide a method for highly efficiently separating and recovering a laminate suitable for plastic recycling, which has excellent removability of the coating layer and further suppresses redeposition of the removed coating layer components. There is a particular thing. Another object of the present invention is to provide a method for producing a high-quality molded article obtained by heat-molding a recovered plastic base material.

That is, the present invention provides a step of crushing a laminate comprising at least a plastic base material and a coating layer in contact with the plastic base material into fluffs having an average size of 5 mm or less, and detaching the fluffs after crushing. A method for separating and recovering a laminate, the method comprising the step of detaching the coating layer from a plastic substrate by contacting with a liquid,
The present invention relates to a method for separating and recovering a laminate, wherein the content of the laminate is 10% by mass or more based on the total mass of the desorbed liquid.

The present invention also relates to a method for separating and recovering the above-mentioned laminate, which includes a step of further pulverizing into fluff having an average size of 1 mm or less after the step of crushing.

The present invention also relates to a method for separating and recovering the above-mentioned laminate, characterized in that the step of pulverizing is performed under cooling means.

The present invention also relates to a method for separating and recovering the above-mentioned laminate, in which the plastic base material contains polyolefin.

The present invention also relates to a method for separating and recovering the laminate, wherein the plastic base material is a plastic film.

The present invention also relates to a method for separating and recovering the above-mentioned laminate, in which the desorbed liquid contains water and a surfactant.

The present invention also relates to a method for producing a molding material, which includes a step of melt-kneading the plastic base material recovered by the laminate separation and recovery method.

Furthermore, the present invention relates to a method for producing a molded body, which further includes a step of heat-molding a molding material obtained by the above-described production method.

ADVANTAGE OF THE INVENTION According to the present invention, it is possible to provide a method for highly efficiently separating and recovering a laminate suitable for plastic recycling, which has excellent detachability of the coating layer and further suppresses redeposition of detached coating layer components. . Furthermore, it is possible to provide a method for producing a high-quality molded article obtained by heat-molding the recovered plastic base material.

The embodiments of the present invention will be described in detail below, but the embodiments or description of requirements described below are examples of the embodiments of the present invention, and the present invention does not exceed the gist thereof. Not limited.

The present invention includes a step of crushing a laminate comprising at least a plastic base material and a coating layer in contact with the plastic base material into fluffs having an average size of 5 mm or less (hereinafter also referred to as a crushing step); A method for separating and recovering a laminate, the method comprising the step of bringing crushed fluff into contact with a desorption liquid to desorb the coating layer from the plastic substrate (hereinafter also referred to as desorption step), the method comprising: The content thereof is 10% by mass or more based on the total mass of the desorbed liquid.

By including the step of crushing the laminate used in the present invention into fluffs having an average size of 5 mm or less before the desorption step, the throughput of the laminate during the desorption step can be increased. Furthermore, since the releasability is improved and the time required for the desorption process can be shortened, it is possible to suppress the coating layer from re-adhering to the substrate after desorption. Furthermore, because the fluff size is small, when the fluff recovered after desorption is melted and kneaded, the fluff is uniformly supplied and dispersed to an extruder, etc., which improves the quality of recycled materials and stabilizes production. It becomes possible.

<Separation and recovery method>
The laminate separation and recovery method of the present invention includes the steps of crushing a plastic base material and a laminate having a coating layer in contact with the plastic base material into fluffs having an average size of 5 mm or less; , a step of bringing the crushed fluff into contact with a desorption liquid to remove the coating layer, and the content of the laminate is 10% by mass or more based on the total mass of the desorption liquid. In the present invention, after the crushing step, a step of finely pulverizing the material into fluffs having an average size of 1 mm or less (hereinafter also referred to as a pulverizing step or a pulverizing step) may be included.

<Process of crushing the laminate, crushing process>

The separation and recovery method of the present invention includes a method of crushing the laminate into fluffs having an average size of 5 mm or less. As a crushing method, a known crushing device can be used, such as a method using a cutter mill (rotary cutter), jaw crusher, impact crusher, stamp mill, ring mill, roller mill, jet mill, or hammer mill. It will be done. Examples of the crushing device using a cutter mill include MF45-700WRS manufactured by Tanaka, PF-2000 type manufactured by Nippon Seam, and the like.

An example of the crushing process in the present invention is shown below.
The laminate is input from the laminate input port of the crushing device, and is crushed to a predetermined size or less in the crushing section using water supplied from the water inlet, if necessary. A known structure can be used for the crushing part. In the crushing section, it is preferable to use a rotary cutter that crushes using shearing force.

In the crushing process, a detergent or the like may be added to the water in order to wash away dirt such as contents adhering to the laminate. Further, a component of a desorption liquid may be included. When the water used in the crushing process contains components of a cleaning agent and a desorption liquid, separation in the desorption process can be promoted.

As the crushing progresses and the size of the fluff falls below a certain level, it passes through a screen installed at the bottom of the crushing section due to its own weight along with water. A screen refers to something that has the role of a filter that allows things smaller than a certain size to pass through, and is sometimes called a filter or grid. The shape of the screen may be circular, diamond-shaped, fan-shaped, etc., and can be appropriately selected depending on the hardness and thickness of the fluff.

The long side of the fluff can be adjusted depending on the size of the screen used. For example, if the screen shape is circular, by using a screen with a diameter of 15 mm, the average value of the fluff size can be controlled to about 15 mm. However, it is also possible to adjust the size of the fluff by adjusting the amount of laminates fed into the crusher, the residence time of the laminates in the crusher, etc.

The mass of water used in the crushing step is preferably 10 to 100 times, more preferably 15 to 80 times, even more preferably 20 to 60 times the mass of the laminate.
Within the above range, the amount of water for cooling the laminate will be sufficient, and water will constantly flow in and out of the fractured portion, thereby suppressing a local temperature rise in the fractured portion due to shearing. Thereby, fusion and softening of the resin base material of the laminate can be suppressed.
In addition, by setting the amount of water within the above range, not only fluff but also unnecessary components such as fine ink pieces and adhesive pieces generated during crushing can easily pass through the above-mentioned screen, and the laminate in the crushing part This prevents stagnation and screen clogging due to unnecessary components.
As a result, the laminate does not accumulate excessively in the crushing portion, and it is possible to suppress the fusion of the resin base material and the generation of fine pieces due to excessive crushing.
Note that the mass of water used in the crushing process represents the mass of water that is input into the crusher per minute, and the mass of the laminate represents the mass of the laminate that is input into the crusher per minute.
Further, after the crushing step, known steps such as washing, draining, dehydration, drying, etc. may be added as appropriate.

The separation and recovery method of the present invention may include a first sorting step of sorting at least a specific plastic base material before the crushing step so as to obtain a molding material with high purity. The sorting method used in the first sorting may be the method described in the second sorting step described later, or, for example, the type of plastic base material may be determined using a sensor or the like, and certain base materials and other A method of sorting the base materials using wind pressure or the like may also be used.
Moreover, before the crushing process, a rough crushing process may be included in which the laminate is crushed into a size that can be easily fed into a crushing device. Examples of the device used in the rough crushing step include a hydraulic cutter.

In the present invention, the average size of fluff after crushing the laminate is 5 mm or less. More preferably, it is 3 mm or less, and still more preferably 1 mm or less. When it is 5 mm or less, releasability becomes good. Furthermore, since fluff is uniformly incorporated during melt-kneading, the properties of the recycled material are stabilized.

<Fine pulverization process, pulverization process>
The separation and recovery method of the present invention may include a step of pulverizing into fluff with an average size of 1 mm or less. As a crushing method, a known crushing device can be used, such as a screw mill, stamp mill, disk mill, pin mill, screen mill, cutter mill that uses impact and shear, or a screw mill that uses impact and shear, and a screw mill that uses impact and shear. An example is a ball mill. In addition, there is a mortar-type extruder, which is a device that can be pulverized in a solid state by setting the melt kneader to a temperature below the melting temperature of the resin, and these pulverization methods may be repeated or two or more types may be used in combination. .

The pulverizing step is preferably carried out under cooling means using a cryogen, if necessary. The temperature of the cryogen used for cooling is preferably 0°C or lower, more preferably -20°C or lower, and still more preferably -60°C or lower. By keeping the temperature of the cryogen used for cooling below 0°C, it can be expected to have the effect of preventing melting of the plastic due to shear heat generation during crushing, improving the separation and detachability of the laminate. The lower the temperature, the faster it can be turned into powder, and furthermore, by crushing at a temperature below the embrittlement temperature of the plastic, it is possible to crush the plastic without changing its properties.
Examples of the cryogen used for cooling include cooling water, liquid nitrogen, and dry ice.

In the crushing process, the size of the fluff can be adjusted by adjusting the type and rotation speed of the crushing blades, the gap between the blades, the cooling temperature, etc.
The average size of the fluff obtained after pulverization is preferably 1 mm or less. More preferably 1 μm to 1 mm, still more preferably 10 μm to 800 μm, even more preferably 100 μm to 600 μm. If it is 1 mm or less, the time for the desorbed liquid to permeate from the end face of the fluff to the center is shortened, and separation and recovery can be performed efficiently, resulting in even better desorption performance. Furthermore, since fluff is incorporated more uniformly during melt-kneading, the properties of the recycled material are stabilized and improved.

<Step of detaching the coating layer, detachment step>
The separation and recovery method of the present invention includes the step of bringing a plastic substrate and a laminate having a coating layer in contact with the plastic substrate into contact with a detachment liquid to detach the coating layer. Note that the coating layer that is detached from the base material by the detachment liquid is also referred to hereinafter as a detachment layer (including a coating layer that is not in direct contact with the plastic substrate).

In the present invention, "detachment" refers to the detachment of the base material from the laminate by at least a part of the desorption layer being dissolved or swollen by a desorption liquid and peeled off, and (1) desorption layer (2) cases where the release layer is not dissolved but is peeled off due to neutralization, swelling, etc. and released from the base material.

The purpose of the present invention is for the plastic base material after desorption to become a molding material that is a high-quality recycled base material, so as much as possible of the desorption layer etc. is removed from the plastic base material. An embodiment in which it is removed is preferred. Specifically, it is preferable that at least 50% by mass or more of 100% by mass of the desorption layer is desorbed. More preferably, 60% by mass or more, still more preferably 80% by mass or more, particularly preferably 90% by mass or more is desorbed. This does not necessarily mean that the coating layer will peel off from the interface with the substrate.

<Desorption liquid>
The desorption liquid may be one that swells and dissolves the coating layer, and can be appropriately selected in consideration of ease of desorption of the coating layer, which will be described later. Examples of such a desorption liquid include water, a basic aqueous solution, and an acidic aqueous solution. From the viewpoint of the environment and maintaining the properties of recycled materials using recovered plastic base materials, an aqueous solution is preferable. The desorption liquid preferably contains water in an amount of 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more.
These desorption liquids may be heated. The temperature of the desorption liquid when the laminate is immersed is preferably in the range of 25 to 120°C, more preferably 30 to 100°C, particularly preferably 50 to 80°C. The higher the desorption temperature is, the more preferable it is from the viewpoint of releasability, and the lower the desorption temperature is, the more preferable it is from the viewpoint of suppressing substrate curling and reattachment.

The release liquid is more preferably a basic aqueous solution containing a basic compound from the viewpoint of removing a urethane adhesive layer commonly used in packaging materials.

The immersion time in the desorption solution is preferably in the range of 1 minute to 24 hours, more preferably 1 minute to 6 hours, still more preferably 1 minute to 1 hour, and even more preferably 1 minute to 10 minutes.

In order to improve the desorption efficiency, it is preferable to stir or vibrate the desorption liquid, circulate it, or the like.
The rotational speed of the stirring blade is preferably 80 to 5000 rpm, more preferably 80 to 4000 rpm.

[Surfactant]
It is preferable that the desorption liquid contains water and a surfactant. The surfactant mainly plays a role in improving the releasability of the coating layer. This is thought to be because the action of the surfactant makes it easier for the release liquid to penetrate into coating layers such as the primer layer, printing layer, and adhesive layer, promoting release properties. In addition, when the amount of the laminate relative to the desorbing liquid is increased during separation and recovery, the laminate and the separated base material tend to curl with the desorbed ink pieces etc. However, it is difficult to cleanly remove ink particles etc. caught in the curls. However, since the desorption liquid contains a surfactant, the surfactant is adsorbed onto the surface of the laminate and the separated base material, thereby suppressing curling. As a result, detachability is improved and re-adhesion can be suppressed.
Furthermore, when the detachment liquid contains a surfactant, it is possible to detach the coating layer in contact with the plastic substrate even if the detachment layer does not have detachability due to the action of a basic compound.

The HLB value is an index value related to the affinity of surfactants for water and oil, and is divided into equal parts, with the HLB value of substances without hydrophilic groups being 0 and the HLB value of substances having only hydrophilic groups being 20. be. The concept of HLB was proposed by William Griffin of the Atlas Powder Company in 1949, and several methods for determining it by calculation have been proposed. In the present invention, the HLB value can be determined from the following equation using the Griffin method.
Formula) HLB=20×[(molecular weight of hydrophilic group contained in surfactant)/(molecular weight of surfactant)]
Examples of the hydrophilic group contained in the surfactant include a hydroxyl group and an ethyleneoxy group.

It is preferable that the HLB value of the surfactant used in the present invention is 7 or more. When the HLB is 7 or more, it exhibits excellent detachability and re-deposition prevention properties. The HLB value of the surfactant is preferably 8 or more, more preferably 10 or more. Further, the HLB value of the surfactant is preferably 20 or less, more preferably 19 or less, and still more preferably 17 or less. It is preferable that the HLB value is 20 or less because it has excellent antifoaming properties.

Types of surfactants include, for example, nonionic, anionic, cationic, and amphoteric surfactants, and suitable types and amounts can be selected and used depending on the required properties. From the viewpoint of detachability and foamability, at least one kind selected from the group consisting of anionic surfactants and nonionic surfactants is preferable.
Further, the surfactant preferably has a structure in which alkylene oxide (hereinafter also referred to as AO) is added, since this improves desorption properties and re-deposition prevention properties.

(Nonionic surfactant)
The nonionic surfactant is not particularly limited, but 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 above addition may be either random addition or block addition. Further, the alkylene oxide preferably has 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 of 8 to 24 carbon atoms, or alkylene oxide adducts of alkylphenols having a total of 8 to 12 carbon atoms. It will be done. The above primary or secondary alcohol having a total of 8 to 24 carbon atoms may be either saturated or unsaturated.
Examples of the primary or secondary alcohol having a total of 8 to 24 carbon atoms include lauryl alcohol, stearyl alcohol, oleyl alcohol, dodecyl alcohol, arachidyl alcohol, behenyl alcohol, lignoceryl alcohol, myristyl alcohol, and the like.
Furthermore, examples of the alkylene oxide added to the alcohol include ethylene oxide, propylene oxide, and butylene oxide, and it is preferable that ethylene oxide is essential. The number of moles of alkylene oxide added is preferably 1 to 100 moles, more preferably 2 to 50 moles, per mole of alcohol or alkylphenol. It is preferable that the content is within the above range because it has particularly excellent releasability.

[Fatty acid-based nonionic surfactant]
The structure of the fatty acid-based nonionic surfactant is not particularly limited, but examples include alkylene oxide adducts of higher fatty acids having a total of 10 to 24 carbon atoms, and saturated or unsaturated surfactants having a total of 10 to 24 carbon atoms. Examples include fats and oils made of esters of higher fatty acids and glycerin, and alkylene oxide adducts of mixtures of the above-mentioned fats and oils and 2 to 10 polyhydric alcohols. The above-mentioned higher fatty acids having a total of 10 to 24 carbon atoms may be either saturated or unsaturated.
Examples of the higher fatty acids having a total of 10 to 24 carbon atoms 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, Examples include unsaturated higher fatty acids such as linolenic acid, erucic acid, and ricinoleic acid. Examples of the di- to decavalent polyhydric alcohol include ethylene glycol, propylene glycol, glycerin, polyglycerin, sorbitol, sorbitan, and sucrose. The type of alkylene oxide and the number of moles added are the same as those described in the [Alcoholic nonionic surfactant] section above.

[Amine-based nonionic surfactant]
Examples of the amine-based nonionic surfactant include AO adducts of saturated or unsaturated primary or secondary amines having a total of 8 to 36 carbon atoms. Examples of amines include 2-ethylhexylamine, di2-ethylhexylamine, laurylamine, dilaurylamine, tetradecylamine, ditetradecylamine, hexadecylamine, dihexadecylamine, stearylamine, distearylamine, oleylamine, di- Examples include oleylamine. Further, the type of AO and the number of moles added are the same as above.

(Anionic surfactant)
Preferably, the anionic surfactant is a non-soap surfactant, such as a sulfonic acid-based anionic surfactant, a sulfate-based anionic surfactant, a carboxylic acid-based anionic surfactant, or a phosphate-based anionic surfactant. Examples include anionic surfactants.

[Sulfonic acid-based anionic surfactant]
Examples of the sulfonic acid-based anionic surfactants include alkylsulfonic acids, alkylbenzenesulfonic acids, alkylnaphthalenesulfonic acids, alkyldiphenyl ether disulfonic acids, alkylmethyltaurine, sulfosuccinic acid diesters, alkylene oxide adducts of sulfonic acids, and these. Examples include salt. Specific examples include hexane sulfonic acid, octanesulfonic acid, decane sulfonic acid, dodecane sulfonic acid, toluene sulfonic acid, cumene sulfonic acid, octylbenzenesulfonic acid, dodecylbenzenesulfonic acid, dinitrobenzenesulfonic acid, and lauryl dodecyl phenyl ether disulfone. An acid etc. can be used.

[Sulfate ester anionic surfactant]
Examples of the sulfate-based anionic surfactant include sulfuric esters (alkyl ether sulfuric esters), alkylene oxide adducts of sulfuric esters, and salts thereof. Specific examples include lauryl sulfate, myristyl sulfate, and polyoxyethylene lauryl ether sulfate.

[Carboxylic acid-based anionic surfactant]
Examples of the carboxylic acid-based anionic surfactant include alkyl carboxylic acids, alkylbenzene carboxylic 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-based anionic surfactant]
Examples of the phosphoric ester-based anionic surfactant include phosphoric esters (alkyl ether phosphates), alkylene oxide adducts of phosphoric 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 having 2 to 24 carbon atoms or an alkenyl group having 2 to 24 carbon atoms, and more preferably has an alkyl group having 8 to 18 carbon atoms. The alkyl group or alkenyl group may be linear or branched.
Further, 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 added is preferably 1 to 12 moles, more preferably 1 to 8 moles, per mole of alcohol or alkylphenol. It is preferable that the content is within the above range because it has particularly excellent releasability.

Examples of the salt constituting the above-mentioned anionic surfactant include metal salts such as sodium, potassium, magnesium, and calcium. These salts may be used alone or in combination of two or more.
Among these, preferable anionic surfactants are sulfonate type and phosphate type from the viewpoint of desorption and re-deposition prevention properties, and more preferable are alkyl sulfonate and polyoxyalkylene alkyl ether sulfonic acid. salts, polyoxyalkylene alkyl ether phosphates, etc.

(Cationic surfactant)
Examples of the cationic surfactant include alkylamine salts and quaternary ammonium salts. Specifically, stearylamine acetate, trimethylyacyanmonium chloride, trimethyltallow ammonium chloride, dimethyldioleylammonium chloride, methyloleyldiethanol 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.

(Ampholytic surfactant)
Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, and imidazoline. Examples include derivatives.

These surfactants may be used alone or in combination of two or more. The content of the surfactant in the desorption solution 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 desorption solution. , more preferably 0.03 to 5% by weight, still more preferably 0.05 to 3% by weight. If it is 0.001% by mass or more, it is preferable because it suppresses curling of the base material and has excellent releasability, and also suppresses redeposition of detached coating layer components, and if it is 10% by mass or less, it is preferable from the viewpoint of antifoaming property. It is preferable.

[Defoaming agent]
In the present invention, it is also preferable that the desorption liquid further contains an antifoaming agent. By using an antifoaming agent in combination with the above-mentioned surfactant, it is possible to exhibit good antifoaming properties without reducing desorption properties and anti-redeposition properties, and to suppress foaming caused by the surfactant. . Examples of antifoaming agents include silicone compounds and non-silicone compounds.

(Silicone compound)
Examples of the silicone compound include emulsion type, self-emulsifying type, oil type, oil compound type, and solvent type.
Emulsion type is a silicone antifoaming agent that emulsifies a silicone oil compound with an activator to form an O/W type (oil in water type) emulsion.For example, "KM-89" manufactured by Shin-Etsu Chemical Co., Ltd. KM-98'', ``FC2913'' and ``SILFOAMSE47'' manufactured by Asahi Kasei Wacker Silicone, and ``BYK-015'' and ``BYK-1640'' manufactured by BYK Chemie Japan.
Self-emulsifying type antifoaming agents are silicone antifoaming agents with 100% active ingredients that become an emulsion when diluted with water and mixed.For example, "KS-540" and "X-50-1176" manufactured by Shin-Etsu Chemical Co., Ltd. , "SILFOAM SD670" and "SILFOAM SD850" manufactured by Asahi Kasei Wacker Silicone.
The oil type is a 100% silicone oil antifoaming agent that does not contain solvents or additives. AK12500'' and BYK-1770 manufactured by BYK Chemie Japan.
The oil compound type is a silicone antifoaming agent made by blending silica particles with silicone oil, such as "KM-89" and "KM-98" manufactured by Shin-Etsu Chemical, "SILFOAM SC370" manufactured by Asahi Kasei Wacker Silicone, Examples include "PULPSIL22274VP" and "BYK-017" and "BYK-018" manufactured by BYK Chemie Japan.
Solvent type is a silicone antifoaming agent made by dissolving silicone oil in a solvent, such as "KM-89" and "KM-98" manufactured by Shin-Etsu Chemical, "BYK-019" manufactured by BYK Chemie Japan, "BYK-025" is an example.

(Non-silicone compound)
Examples of the non-silicone compounds include fatty acid ester compounds, urea resin compounds, paraffin compounds, polyoxyalkylene glycol compounds, acrylic ester copolymers, ester polymers, ether polymers, and amide polymers. Examples include emulsified types of mineral oil, polysiloxane adducts, fluorine compounds, vinyl polymers, acetylene alcohol, acrylic polymers, special vinyl polymers, ethylene glycol, and higher alcohols (octyl alcohol, cyclohexanol, etc.).

The antifoaming agents may be used alone or in combination of two or more. The content of the antifoaming agent in the desorption solution is preferably in the range of 0.0001 to 5% by mass, more preferably in the range of 0.001 to 4.5% by mass, based on the mass of the desorption solution. It is more preferably 0.01 to 4% by weight, still more preferably 0.02 to 3.5% by weight, particularly preferably 0.03 to 3% by weight. When it is 0.0001% by mass or more, the antifoaming property is excellent, and when it is 5% by mass or less, the desorption property and re-deposition prevention property are excellent.

The above antifoaming agents have good alkali resistance, and from the viewpoint that when combined with the above surfactants, desorption properties and anti-redeposition properties are unlikely to deteriorate, emulsion-type silicone compounds, self-emulsifying silicone-type compounds, etc. It is preferably at least one selected from the group consisting of silicone compounds and non-silicone compounds.

[Basic compound]
As described above, the desorption liquid used in the present invention is preferably a basic aqueous solution containing a basic compound from the viewpoint of desorption of the urethane adhesive layer commonly used in packaging materials.
The basic compound is not particularly limited, and examples include sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH) ₂ ), ammonia, barium hydroxide (Ba(OH) ₂ ), Sodium carbonate (Na ₂ CO ₃ ) 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 0.1 to 20% by mass, more preferably 0.3 to 15% by mass, even more preferably 0.5 to 15% by mass, based on the mass of the basic aqueous solution. It is in the range of 10% by mass. Within the above range, the basic aqueous solution can maintain sufficient basicity to recover the plastic substrate by dissolving or swelling the release layer described below.

The desorption liquid permeates through the end portion of the laminate, contacts the desorption layer, and dissolves or swells, thereby separating the plastic base material and the desorption layer. Therefore, in order to proceed with the desorption process efficiently, it is preferable that the desorption layer be exposed in the cross section when the laminate is crushed and immersed in the desorption liquid. In such a case, the base material layer can be detached in a shorter time.

[Fluff content before desorption (also called processing amount)]
The content of the laminate when the laminate is separated in the desorption solution is 10% by mass or more, preferably 10% by mass or more and 100% by mass or less, more preferably 10% by mass or more and 100% by mass or less, based on the total mass of the desorption solution. The content is 15% by mass or more and 70% by mass or less, more preferably 20% by mass or more and 50% by mass or less. A content of 10% by mass or more is preferable from the viewpoint of processing efficiency. A content of 100% by mass or less is preferable from the viewpoints of detachability, anti-redeposition properties, and stirring efficiency.

<Laminated body>
The laminate used in the present invention includes a plastic base material and a coating layer. Examples of the coating layer include at least one coating layer selected from the group consisting of a primer layer, a printing layer, and an adhesive layer. The layer in contact with the plastic base material is desorbed by the above-mentioned desorption liquid, making it possible to collect and recycle the plastic base material. In the present invention, in order to improve the releasability upon contact with the desorption liquid, it is preferable to provide a primer layer having high affinity with the desorption liquid in contact with the plastic base layer.

<Print layer>
In the present invention, the printing layer may be provided in contact with the plastic substrate, or in the case where the laminate has a primer layer, it may be provided in contact with the primer layer. The printed layer is a layer that forms an arbitrary printed pattern for the purpose of decoration, giving a sense of beauty, indicating contents, expiration date, manufacturer or seller, etc., and includes a solid printed layer. The printing layer may be formed of a single layer or a plurality of layers. When the printing layer contains a water-soluble resin or a compound having an acidic group, which will be described later, releasability is imparted.
The printing ink used to form the printing layer can be manufactured by dissolving and/or dispersing at least a colorant, a dispersant, and a binder resin in a solvent, and may contain other components as necessary. You can.

[Colorant]
The printing 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 provide 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, navy blue, ultramarine blue, carbon black, and graphite; extender pigments such as calcium carbonate, kaolin, clay, barium sulfate, aluminum hydroxide, and talc.
As the organic pigment, soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, condensed polycyclic pigments, etc. are preferably used.
Note that the pigments are not limited to these, and those described by the generic names of Color Index can be used as appropriate. Among these, when the desorbing liquid is a basic aqueous solution, a pigment that does not dissolve in the basic aqueous solution and has alkali resistance is preferable. By preventing pigment elution, the base aqueous solution can be easily reused.
The alkali resistance of a pigment is generally estimated based on the skeleton or structure of the pigment, and examples of pigments with alkali resistance include inorganic pigments, C.I. I. Pigment Blue 15, C. I. Pigment Yellow 83 is mentioned.
When the pigment is titanium oxide, the content of titanium oxide in the printing layer is preferably 20 to 80% by weight, more preferably 30 to 75% by weight. Further, 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 printing layer is preferably 0.5 to 60% by mass, more preferably 10 to 50% by mass. Mass%.

[Dispersant]
When the print layer contains a pigment derivative and/or a resin-type dispersant as a colorant dispersant, the releasability is improved. Furthermore, the dispersion stability and stability over time of the ink are improved. Although these may be used alone, it is preferable to use them together because the dispersion stability and stability over time will be further improved.

(pigment derivative)
Pigment derivatives are compounds in which substituents have been introduced into the pigment skeleton. In the printing ink, the pigment skeleton of the pigment derivative is adsorbed to the surface of the pigment in the printing ink, and the substituent part of the pigment derivative is oriented to the solvent in the printing ink, which has the effect of dispersing the pigment in the printing ink. have
Examples of pigment derivatives include those in which functional groups such as carboxyl groups, sulfonic acid groups, carbonyl groups, and sulfonyl groups are added to the skeleton of pigments such as phthalocyanine, azo, anthraquinone, and quinacridone, and salts thereof. can be preferably used. These can be used alone or in combination.

As commercially available pigment derivatives, Solsperse 5000, Solsperse 12000 (manufactured by Japan Lubrizol), BYK-SYNERGIST 2100, BYK-SYNERGIST 2105 (manufactured by Big Chemie Japan), Efka 6745, Efka 6750 (manufactured by BASF), etc. are preferably used. can do. These can be used alone or in combination.

Preferably, the pigment derivative exhibits the same or similar color as the pigment in the ink. For example, when added to black ink or cyan ink, phthalocyanine pigment derivatives can be preferably used as the pigment derivatives.

The total amount of pigment derivatives is preferably 0.01 to 10% by weight, more preferably 0.05 to 6% by weight, and preferably 0.1 to 4% by weight based on the entire colorant. More preferred. When the amount is 0.01% by mass or more, the dispersion stability of the printing ink will be good and the releasability will also be improved. Further, by having a content of 0.01 to 10% by mass, it contributes to improving detachability and suppressing redeposition, and can be recycled into a high-quality recycled molding material.

(Resin type dispersant)
The resin-type dispersant has an affinity site for the pigment composition that has the property of adsorbing to the pigment composition, and a site that is compatible with the pigment composition carrier. It functions to stabilize the dispersion in the carrier. Specifically, resin-type dispersants include polycarboxylic acid esters such as polyurethane and polyacrylate, unsaturated polyamides, polycarboxylic acids, polycarboxylic acid (partial) amine salts, polycarboxylic acid ammonium salts, and polycarboxylic acid alkylamine salts. , polysiloxanes, long-chain polyaminoamide phosphates, hydroxyl group-containing polycarboxylic acid esters, modified products thereof, amides formed by the reaction of poly(lower alkylene imine) with polyesters having free carboxyl groups, and their salts. Water-soluble oil-based dispersants such as (meth)acrylic acid-styrene copolymer, (meth)acrylic acid-(meth)acrylic acid ester copolymer, styrene-maleic acid copolymer, polyvinyl alcohol, polyvinylpyrrolidone, etc. Resins, water-soluble polymer compounds, polyesters, modified polyacrylates, ethylene oxide/propylene oxide adducts, phosphoric esters, etc. are used, and these can be used alone or in combination of two or more, but It is not necessarily limited to these.

The total amount of the resin type dispersant is preferably 0.01 to 30% by mass, more preferably 0.05 to 20% by mass, and 0.1 to 10% by mass based on the entire colorant. It is even more preferable. When the amount is 0.01% by mass or more, the dispersion stability of the printing ink will be good and the releasability will also be improved. Further, if the content is 30% by mass or less, the water resistance of the printed layer will be good.

[Binder resin]
Examples of the binder resin for the printing layer include nitrocellulose, cellulose acetate/propionate and other fiber materials, chlorinated polypropylene, vinyl chloride-vinyl acetate copolymer, polyester, acrylic, urethane resin, and acrylic urethane. , polyamide-based, polybutyral-based, cyclized rubber-based, chlorinated rubber-based, or a combination of these as appropriate can be used. When the printing layer contains a water-soluble resin or a compound having an acidic group, which will be described later, the printing layer is given a releasability function. These resins may be used alone or in combination of two or more.

[Primer layer]
The laminate used in the present invention may have a primer layer. When the laminate has a primer layer, the primer layer is disposed in contact with the plastic base material and is formed from a water-soluble resin or a primer composition containing a compound having an acidic group. Even if there is a printed layer or adhesive layer that does not have removability, it plays the role of desorbing the plastic base material by dissolving and peeling with a desorbing liquid.

(Water-soluble resin)
The water-soluble resin may be any resin that can swell or dissolve in water and be detached from the plastic base material. The water may be heated to a temperature of about 25 to 100°C. Thereby, the primer layer can be removed with water (including hot water).
Such resins can be selected from known resins as long as they do not impair water solubility, such as water-soluble polyester resins, water-soluble polyamide resins, water-soluble polyimide resins, water-soluble acrylic resins, water-soluble polyurethane resins, and water-soluble polyurethane resins. Examples include water-soluble polyallylamine resin, water-soluble phenol resin, water-soluble epoxy resin, water-soluble phenoxy resin, water-soluble urea resin, water-soluble melamine resin, polyvinyl alcohol resin, and modified products of these resins. These can be used alone or in combination of two or more. Among them, polyvinyl alcohol (PVA) resin is preferably used from the viewpoint of easy availability and removability.
When the water-soluble resin has film-forming properties, the water-soluble resin may be used as the binder resin constituting the primer layer.

In addition to unmodified polyvinyl alcohol, polyvinyl alcohol resins include modified polyvinyl alcohol obtained by copolymerizing various monomers during the production of vinyl ester resins and saponifying this, 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 also be used. Further, modified polyvinyl alcohol may be further modified after modification. These modifications can be carried out within a range that does not impair the water solubility of the polyvinyl alcohol resin.
These resins may be used alone or in combination of two or more.

Preferred examples of the polyvinyl alcohol resin include resins containing structural units having primary hydroxyl groups in side chains and ethylene-modified polyvinyl alcohol resins. Among these, polyvinyl alcohol resins containing constitutional units having primary hydroxyl groups in their side chains are preferred because they have excellent melt moldability and water solubility. The number of primary hydroxyl groups in these structural units is usually 1 to 5, preferably 1 to 2, and more preferably 1. Moreover, it is preferable to have a secondary hydroxyl group in addition to the primary hydroxyl group.

The saponification degree (measured according to JIS K 6726) of the polyvinyl alcohol resin used in the present invention is usually 60 to 100 mol%. Further, the preferable range of the degree of saponification varies depending on the modified species; for example, in the case of unmodified polyvinyl alcohol resin, it is usually 60 to 99.9 mol%, preferably 70 to 99.0 mol%, more preferably 75 to 98 mol%. .5%. The degree of saponification of the modified polyvinyl alcohol resin containing a side chain 1,2-diol constituent unit 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, water solubility tends to decrease. The degree of saponification 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%.
It is preferable that the degree of saponification is within the above range because it provides excellent water solubility and good desorption properties. It is also preferred because it has excellent coating properties when forming a primer layer.

The average degree of polymerization of the polyvinyl alcohol resin (measured according to JIS K 6726) is usually 100 to 3,000, preferably 150 to 2,000, more preferably 180 to 1,000, particularly preferably 200 to 800.

(Compound with 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. Thereby, the primer layer can be removed with the above-mentioned basic aqueous solution.

Examples of the resin having an acidic group include cellulose resin, urethane resin, polyamide resin, vinyl chloride/vinyl acetate copolymer, ketone resin, polyester resin, and (meth)acrylic resin. Examples of the acidic group include a carboxy group, a phosphoric acid group, a sulfo group, a sulfino group, and esters or salts thereof.
Further, as the resin having an acidic group, a rosin modified resin having an acid value such as a maleated rosin or a fumarated rosin can be used.
In addition, as resins having acidic groups, polymerizable monomers having a carboxy group such as itaconic acid, maleic acid, fumaric acid, and cinnamic acid; polymerizable monomers that are acid anhydrides such as itaconic anhydride and maleic anhydride; sulfone Styrene-(meth)acrylic copolymerized with a polymerizable monomer having an acidic group such as a polymerizable monomer having a sulfonic acid group such as styrene; a polymerizable monomer having a sulfonamide group such as vinylbenzenesulfonamide; A radical copolymer such as a resin, a styrene-(anhydrous) maleic acid resin, a terpene-(anhydrous) maleic acid resin, or an acid-modified polyolefin resin can be used.
These may be used alone or in combination of two or more.

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; oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, sorbic acid, etc. unsaturated fatty acids; 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 ; Examples include acid anhydrides such as trimellitic anhydride and pyromellitic anhydride.
A low molecular weight compound having an acidic group can form a primer layer by using it in combination with the above-mentioned resin having an acidic group or a known binder resin constituting a known primer layer.

The primer layer preferably contains a compound having an acidic group from the viewpoint of suitability for recoating. Further, from the viewpoint of printability, it is preferable to include a urethane resin having an acidic group, an acrylic resin having an acidic group, or a rosin modified resin. The primer layer may contain one type of these resins alone or a combination of two or more types.

[Urethane resin with acidic group]
The urethane resin having an acidic group is not particularly limited, and examples thereof include a urethane resin obtained by reacting a polyol and a polyisocyanate having an acidic group, and a urethane resin obtained by reacting a polyol and a polyisocyanate with an acid-modified hydroxyl group. and resins obtained by acid-modifying the amino groups in a urethane urea resin obtained by reacting a polyamine with an isocyanate group in a urethane resin obtained by reacting a polyol with a polyisocyanate.
Further, 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 removability can be improved. Further, when the urethane resin having an acidic group has an isocyanate group, a portion 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 to 10,000, more preferably 1,000 to 5,000. The above-mentioned number average molecular weight is calculated from the hydroxyl value of the polyol, and the hydroxyl value refers to a value measured according to JIS K 0070. When the number average molecular weight of the polyol is 500 or more, the primer layer has excellent flexibility and improves adhesion to the plastic substrate. When the number average molecular weight is 10,000 or less, blocking resistance against plastic substrates is excellent.

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

《Hydroxy acid》
The polyol may also contain a hydroxy acid. The above-mentioned 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 an acid value, and specifically includes a carboxyl group and a sulfonic acid group, with a carboxy group being preferred. As such a hydroxy acid, for example, dimethylolalkanoic acids such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and 2,2-dimethylolvaleric acid are preferably used.

《Polyisocyanate》
The above polyisocyanate is not particularly limited and can be selected from conventionally known polyisocyanates. Preferably, the diisocyanate or triisocyanate is included, and more preferably an aromatic, aliphatic or alicyclic diisocyanate is included. These may be used alone or in combination of two or more.

《Polyamine》
The polyamine used to form the urethane urea is not particularly limited, and is preferably a diamine compound. Further, a diamine having a hydroxyl group may be used since it can introduce a hydroxyl group 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, and still more preferably 20 to 50 mgKOH/g. It is preferable that the content is 15 mgKOH/g or more because the releasability with the desorption liquid becomes good, and it is preferable that the content is 70 mgKOH/g or less because the adhesion to the substrate and the retort resistance are good. The hydroxyl value of the urethane resin is preferably 1 to 35 mgKOH/g, more preferably 10 to 30 mgKOH/g. If it is 1 mgKOH/g or more, the releasability by the desorbing liquid will be good, so it is preferable, and if it is 35 mgKOH/g or less, the adhesion to the substrate will be good, so it is preferable.

The weight average molecular weight of the urethane resin having acidic groups is preferably 10,000 to 100,000, more preferably 15,000 to 70,000, even more preferably 15,000 to 50,000. The molecular weight distribution (Mw/Mn) of the urethane resin is preferably 6 or less. Mw represents weight average molecular weight, and Mn represents number average molecular weight. When the molecular weight distribution is 6 or less, the releasability, drying properties of the primer composition, and retort resistance are excellent. Furthermore, the smaller the molecular weight distribution, that is, the sharper the molecular weight distribution, the more uniformly the dissolution and peeling action by the desorbing liquid occurs, and the releasability of the plastic base material improves. The molecular weight distribution is more preferably 5 or less, still more preferably 4 or less. Further, the molecular weight distribution is preferably 1.5 or more, more preferably 1.2 or more.
In the present invention, Mw, Mn, and molecular weight distribution (Mw/Mn) are polystyrene equivalent values determined by gel permeation chromatography (GPC).

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

The number of urethane bonds in the polyurethane resin having acidic groups is preferably 1 to 3 mmol/g, more preferably 1.5 to 2 mmol/g. Further, the number of urea bonds is preferably 0 to 3 mmol/g, more preferably 0.2 to 1 mmol/g. Further, the total number of urethane bonds and the number of 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 appropriate ranges, the releasability and substrate adhesion are improved.

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

[Rosin modified resin]
Rosin modified resin is a resin prepared using rosin as one of the raw materials. Rosin contains a mixture of resin acids such as abietic acid, palustric acid, isopimaric acid, and levopimaric acid, and these resin acids contain hydrophilic and chemically active carboxy groups, and some contain conjugated double bonds. There are things to prepare for. Therefore, polyhydric alcohols and polybasic acids are combined to perform condensation polymerization, resol, which is a condensate of phenol, is added to the benzene ring contained in the rosin skeleton, and dienophilic maleic anhydride or maleic acid is reacted with Diels-Alder reaction. Various rosin-modified resins have been prepared by adding a maleic acid or maleic anhydride skeleton to the rosin. Various kinds of such rosin modified resins are commercially available, and it is also possible to obtain and use them.

Examples of the rosin-modified resin include maleated rosin, fumarized 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 is derived from the structure thereof. It is preferable to use a compound containing a portion as follows. A resin that “contains in its structure at least one moiety selected from the group consisting of maleic acid, maleic anhydride, fumaric acid, and fumaric anhydride” refers to a resin that contains maleic acid, maleic anhydride, It is prepared using at least one selected from the group consisting of acid, fumaric acid, and fumaric anhydride, such as rosin-modified maleic acid obtained by condensation polymerization of maleic acid or fumaric acid as part of a polybasic acid. Acid resins, rosin-modified fumaric acid resins, maleated rosins and fumarated rosins with structures in which maleic acid, maleic anhydride, fumaric acid, and fumaric anhydride are added as dienophiles through Diels-Alder reactions, and the functionalities contained in these. It means a resin etc. in which other chemical species are polymerized using the group.

The acid value of the rosin modified resin is preferably 10 to 400 mgKOH/g, more preferably 100 to 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 and 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, chloride rubber, butyral, polyacetal resin, petroleum resin, and These modified resins can be mentioned. These resins may be used alone or in combination of two or more.
Among these, the primer layer preferably contains at least one resin selected from the group consisting of cellulose resin, vinyl chloride resin, rosin resin, and acrylic resin. More preferably, vinyl chloride resin or acrylic resin is included.
The mass ratio of the urethane resin having acidic groups to other resins (urethane resin having acidic groups: other resins) is preferably 95:5 to 50:50. If it is within the above range, when the printed layer is peeled off together with the primer layer in a basic aqueous solution, the printed layer will be peeled off in a thin film state and recovery will be easy, which is preferable.

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

The primer layer may be a layer in which the above-mentioned urethane resin having acidic groups is crosslinked with a curing agent. By introducing a crosslinked structure into the primer layer, penetration and bleeding of the printed layer formed on the primer layer are suppressed, and excellent image quality can be exhibited.
Examples of the curing agent include polyisocyanate. 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 those listed above, Examples include silane coupling agents.

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

[Adhesive Layer] The laminate of the present invention may have an adhesive layer. When the laminate has an adhesive layer, the adhesive layer is placed in contact with the plastic base material, contains a compound having an acidic group, and has the role of detaching the plastic base material by dissolving and peeling with a detaching liquid. It is preferable to take on this role. When the adhesive layer contains a resin having an acidic group or a low molecular weight compound having an acidic group, the adhesive layer can be removed using the above-mentioned basic aqueous solution.
For the above-mentioned compound having an acidic group, resin having an acidic group, and low molecular weight compound having an acidic group, the description of (compound having an acidic group) in the above-mentioned [Primer layer] section can be referred to.
Further, the method of forming the adhesive layer is not limited, and it can be formed using a known method.

From the viewpoint of removability, the adhesive layer is a cured 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. It 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 a polyester polyol, at least one polyisocyanate selected from the group consisting of aliphatic polyisocyanates and araliphatic polyisocyanates, and a low molecular compound having an acidic group. It may be.

(Polyester polyol)
The polyester polyol only needs to have an acidic group, and can be appropriately selected from known polyester polyols. By including such a polyester polyol, when a basic aqueous solution is used as a desorption liquid, it is preferable because the desorption property is improved by having an ester bond that has a high affinity with a basic compound. One type of polyester polyol may be used alone, or two or more types may be used in combination.

Polyester polyols include, but are not particularly limited to, polyester polyols obtained by reacting carboxy group components and hydroxyl group components; ring-opening lactones such as polycaprolactone, polyvalerolactone, and poly(β-methyl-γ-valerolactone). A polyester polyol obtained by polymerization is preferably used.
Examples of the carboxy group components include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, phthalic anhydride, adipic acid, azelaic acid, sebacic acid, succinic acid, glutaric acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, and anhydrous 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, 1,4-butanediol , 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 3,3'-dimethylolheptane, 1,9-nonanediol, polyoxyethylene glycol, polyoxypropylene glycol, polytetramethylene ether Examples include diols such as glycol, polyether polyol, polycarbonate polyol, polyolefin polyol, acrylic polyol, and polyurethane polyol, or mixtures thereof.
Two or more of the above carboxy group components and hydroxyl group components may be used in combination.

The polyester polyol may be a polyester urethane polyol obtained by reacting a polyisocyanate with a hydroxyl group in a polyol. Because polyester polyol has urethane bonds, it exhibits excellent heat resistance and adhesive properties.
Examples of the polyisocyanates 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. can be mentioned.

Further, the polyester polyol may be an acid anhydride-modified product obtained by reacting an acid anhydride with a hydroxyl group in the polyol. Thereby, a carboxy group, which is an acidic group, can be introduced into the polyester polyol.
Examples of the acid anhydride include pyromellitic anhydride, mellitic anhydride, trimellitic anhydride, and trimellitic acid ester anhydride. Examples of the trimellitic acid ester anhydride include ethylene glycol bisanhydrotrimellitate and propylene glycol bisanhydrotrimellitate.

The acid value of the polyester polyol is preferably 5.0 mgKOH/g or more, more preferably 10.0 mgKOH/g or more. Further, 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, when the polyester polyol is brought into contact with a desorption liquid that is a basic aqueous solution, the basic aqueous solution penetrates and is decomposed, thereby exhibiting better desorption properties.
When the adhesive contains a plurality of polyester polyols, the acid value of the entire polyester polyol can be determined 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, it is possible to exhibit not only coating properties but also sufficient retort resistance, and when it is 20,000 or less, not only coating properties but also release properties are exhibited. It is preferable because it improves

The polyester polyol component may contain a plurality of polyester polyol components in combination, for example, a polyester polyol having a number average molecular weight of 5,000 to 20,000, in order to satisfy various physical properties required for packaging materials. Furthermore, in order to improve adhesion to the substrate, a polyester polyol having a number average molecular weight of less than 3,000 may be included.
The content of the polyester polyol having a number average molecular weight of less than 3,000 is preferably 0 to 30% by mass, more preferably 0 to 20% by mass, based on the total mass of the polyester polyol. When the content is 30% by mass or less, retort resistance can be maintained.

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

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

Examples of the aliphatic polyisocyanate include acyclic aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, and 1,2-butylene diisocyanate; 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 complexes thereof.
The derivative is preferably a nurate type or an adduct type, and more preferably an adduct type. As the aliphatic polyisocyanate, a polyisocyanate derived from hexamethylene diisocyanate (hereinafter also referred to as HDI) is preferred because it can easily ensure a balance between removability and laminate physical properties.

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

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

The blending ratio of the polyol and polyisocyanate may be such that the molar ratio of isocyanate groups in the polyisocyanate to hydroxyl groups in the polyol (NCO/OH) 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 a silane coupling agent, a phosphorus oxygen acid or its derivative, a leveling agent, an antifoaming agent, a reaction accelerator, and an inorganic filler (for example, silica, alumina, mica, talc, aluminum flakes, glass flakes). ), 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 colorant, a filler, a crystal nucleating agent, a catalyst for adjusting the curing reaction, and the like.

<Plastic base material layer>
Examples of the plastic base material include polyolefin resin, polyester resin, polyamide resin, polystyrene resin, vinyl chloride resin, vinyl acetate resin, ABS resin, acrylic resin, acetal resin, polycarbonate resin, polyvinyl alcohol resin, and cellulose plastic. It will be done.

From the viewpoint of reuse as a recycled base material, the plastic base material is preferably a polyolefin base material containing a polyolefin resin. Base materials containing such polyolefin resins include, for example, plastic base materials such as polyethylene (PE) and biaxially oriented polypropylene (OPP), as well as low density polyethylene (LDPE) and linear low density polyethylene (LLDPE). ), high-density polyethylene (HDPE), acid-modified polyethylene, unoriented polypropylene (CPP), acid-modified polypropylene, and copolymerized polypropylene.
The plastic base material may be subjected to gas barrier treatment to become a gas barrier base material.

The thickness of the plastic base layer is not particularly limited, and may be appropriately selected depending on the application. Preferably it is 5 to 200 μm, more preferably 10 to 150 μm. The thinner the thickness, the more likely the base material will curl, and the more difficult it will be to remove it.
Examples of the gas barrier base material include aluminum foil, a plastic base material having a deposited layer of metal such as aluminum, and a deposited layer of metal oxide such as silica or alumina. The thickness of aluminum foil is often used in the range of 3 to 50 μm from an economical point of view. Further, since the aluminum foil, the aluminum vapor deposited layer, and the alumina vapor deposited layer are dissolved in a basic aqueous solution and desorbed, they have removability and can easily separate the plastic base material.

An example of the structure of the laminate used in the present invention is listed below, but the structure is not limited thereto. Furthermore, in the configuration described below, the "plastic base material" does not need to be a single layer, and may be a laminate in which a plurality of base materials are laminated.
Note that the layer in contact with the plastic base material to be separated and recovered only needs to have removability. has removability, the laminate can be said to be a "plastic base material/printed layer" or a "plastic base material/primer layer/printed layer".
・Plastic base material / Printing layer ・Plastic base material / Primer layer / Printing layer ・Plastic base material / Printing layer / Adhesive layer / Plastic base material ・Plastic base material / Primer layer / Printing layer / Adhesive layer / Plastic base material・Base material layer / Printing layer / Adhesive layer / Plastic base material ・Plastic base material / Primer layer / Printing layer / Adhesive layer / Vapor deposition layer / Plastic base material

<Process of separating and recovering plastic base material>
After the desorption step, the separated plastic substrate is recovered. As a recovery method, known means can be applied by utilizing the difference in physical properties between the plastic base material after desorption and the coating layer piece after desorption. For example, a means of floating and sinking using specific gravity or a means of centrifugation can be applied.

Before recovering the plastic base material, a step may be provided to remove components other than the resin base layer, such as ink and adhesive that have been detached from the laminate. Ingredients such as the ink and adhesive mentioned above are made fine by the shear force during the desorption process, so by adjusting the size of the filter using the difference in size from the fluff, the ink adhered to the plastic substrate can be removed. The plastic base material can be recovered while removing minute pieces of adhesive components. There is also a method of separating the plastic base material and the fine particles of the ink or adhesive component using the difference in specific gravity.
The desorption liquid after collecting the plastic base material and removing components other than the plastic base material layer, such as ink and adhesive, may be reused in the desorption step.

After the desorption step, there may be a step of sorting out the resin type of the plastic base material (second sorting step). Examples of the sorting process include a gravity sorting method using a liquid, a wind sorting method, and a near-infrared sorting method.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, resin base materials with a specific gravity lighter than water such as polyethylene and polypropylene, and resin base materials with a specific gravity higher than water such as polyester, nylon, and cellophane, are separated. can be sorted. The specific gravity liquid may be formulated with an organic solvent, an aqueous solution of a metal salt compound, etc. alone or in combination, and the specific gravity may be adjusted as appropriate. Such specific gravity selection can also be performed multiple times.
The recovered plastic base material is reused after undergoing treatments such as dehydration and drying as necessary.

<Reuse of resin base material>
[Process of melt-kneading the recovered plastic base material] The resin base material collected by the above-described separation and recovery method can be melt-kneaded to produce a molding material.
In the melt-kneading process, various additives are added as necessary, and the mixture is mixed using a Henschel mixer, tumbler, disper, etc., followed by a kneader, roll mill, super mixer, Henschel mixer, Shugi mixer, vertical granulator, high-speed mixer, fur mixer, etc. Mix and disperse using matrix, ball mill, steel mill, sand mill, vibration mill, attritor, batch kneader such as Banbury mixer, twin screw extruder, single screw extruder, rotor type twin screw kneader, etc. refers to something. As a result, 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. It is preferable to use a twin-screw extruder in the melt-kneading step.
Additionally, a masterbatch may be manufactured using the recovered plastic base material.

The molding material may further contain a masterbatch or a plastic other than recycled plastic. 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 can be used. The thermoplastic resins contained in the masterbatch may be used alone or in combination of two or more.
The masterbatch may contain alkali metal, alkaline earth metal, or zinc metal soap, hydrotalcite, nonionic surfactant, cationic surfactant, anionic surfactant, amphoteric surfactant, as long as it does not impede the effects of the present invention. It may contain surfactants, antistatic agents, flame retardants such as halogen-based, phosphorus-based or metal oxides, lubricants such as ethylene bisalkylamides, antioxidants, ultraviolet absorbers, and fillers.

[Heat forming process]
A molded body can be obtained by heat-molding the molding material obtained as described above. The heat molding method is not particularly limited, and examples thereof include injection molding, extrusion molding, blow molding, and compression molding.
The molding material produced using the plastic base material recovered by the separation and recovery method of the present invention has an unblocked fluff cross section and has excellent removability, resulting in suppressed adhering components and high quality. It can be used in a variety of fields, including home appliances, stationery, automobile parts, toys and sporting goods, medical use, and building and construction materials.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to these Examples. Note that parts and % in the present invention represent parts by mass and % by mass unless otherwise noted.

<Molecular weight and molecular weight distribution>
The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw/Mn) were measured by GPC (gel permeation chromatography) and determined as a converted molecular weight using polystyrene as a standard substance. The measurement conditions are shown below.
GPC device: Showa Denko Shodex GPC-104
Column: The following columns were connected in series and used.
Showa Denko Shodex LF-404 2 pieces Showa Denko Shodex LF-G
Detector: RI (differential refractometer)
Measurement conditions: Column temperature 40℃
Eluent: Tetrahydrofuran Flow rate: 0.3 mL/min

<Acid value>
The acid value was measured according to the method described in JIS K 0070 (1992).

<Production of primer composition and resin for printing ink>
[Synthesis Example 1-1] (Polyurethane resin P1)
PPA (consisting of a polycondensate of propylene glycol and adipic acid, number average molecular weight 2, 000 polyester polyol) 152.2 parts, PPG (polyether polyol consisting of polypropylene glycol and having a number average molecular weight of 2,000) 15.2 parts, BD (1,4-butanediol) 13.6 parts, IPDI (isophorone) 99.8 parts of 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 isocyanate groups at the ends.
Next, a mixture of 19.2 parts of AEA (2-(2-aminoethylamino)ethanol) and 350 parts of IPA (isopropyl alcohol) was added dropwise at room temperature over 60 minutes, and then reacted at 70°C for 3 hours. A polyurethane resin solution was obtained.
NPAC was added to the obtained polyurethane resin solution to adjust the solid content, and a polyurethane resin P1 with a solid content concentration of 30%, a weight average molecular weight of 27,000, Mw/Mn = 3.1, and an acid value of 0.0 mgKOH/g was obtained. A solution of was obtained.

[Synthesis Example 1-2] (Polyurethane resin P2)
135.7 parts of PPA, 13.6 parts of PPG, DMPA (2,2 -dimethylolpropanoic acid), 105.7 parts of IPDI, and 200 parts of NPAC were charged and reacted at 90°C for 5 hours to obtain a urethane prepolymer solution having isocyanate groups at the terminals.
Next, a mixture of 16.7 parts of AEA and 350 parts of IPA was added dropwise at room temperature over 60 minutes, and then reacted 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, resulting in a polyurethane resin P2 having a solid content concentration of 30%, a weight average molecular weight of 30,000, Mw/Mn=3.0, and an acid value of 39.3 mgKOH/g. A solution of was obtained.

<Manufacture of primer layer forming composition>
[Production Example 1-1] (Primer composition S1)
Stir 87 parts of polyurethane resin P2 solution, 5 parts of ethyl acetate (EA), 5 parts of IPA, and 3 parts of silica particles (P-73 manufactured by Mizusawa Chemical Co., Ltd.: hydrophilic silica particles with an average particle size of 3.8 μm) using a disper. By mixing, a primer composition S1 was obtained.

<Manufacture of printing ink>
[Manufacturing example 2-1] (Printing ink R1)
Indigo pigment P. B. 10 parts of C.I. Pigment Blue 15, 0.2 parts of BYK-SYNERGIST2100 (pigment derivative, manufactured by BYK-CHEMY JAPAN), and 0.2 parts of DISPER BYK-142 (resin type dispersant, manufactured by BYK-CHEMIE JAPAN). 5 parts, 24.3 parts of polyurethane resin P1 solution, 5 parts of PVC solution (vinyl chloride-vinyl acetate copolymer resin solution (Solvine TAO manufactured by Nissin Chemical, solid content 30%, EA solution)), 10 parts of EA, 10 parts of IPA The mixture was mixed and stirred, and a dispersion treatment was performed for 20 minutes using a sand mill as a bead mill. Thereafter, 20 parts of polyurethane resin P1 solution, 10 parts of EA, and 10 parts of IPA were mixed and stirred to obtain printing ink R1.

[Production Example 2-2] (Printing Ink R2) Blue pigment P. B. Mix and stir 10 parts of BYK-SYNERGIST 2100, 0.5 parts of DISPER BYK-142, 24.3 parts of polyurethane resin P2 solution, 5 parts of PVC solution, 10 parts of EA, and 10 parts of IPA, Dispersion treatment was performed for 20 minutes using a sand mill as a bead mill. Thereafter, 20 parts of polyurethane resin P2 solution, 10 parts of EA, and 10 parts of IPA were mixed and stirred to obtain printing ink R2.

<Manufacture of polyol used in adhesives>
[Synthesis Example 2-1] (Polyester polyol B1)
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, a thermometer, a reflux condenser, a dropping tank, and a nitrogen gas introduction tube. 36 parts of acid and 265 parts of sebacic acid were charged, and the temperature was raised to 250° C. with stirring under a nitrogen stream to perform an esterification reaction. After the reaction was continued until a predetermined amount of water was distilled out and 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. Thereafter, 35 parts of isophorone diisocyanate was gradually added, and the reaction was carried out at 150° C. for about 2 hours to obtain a polyester polyurethane polyol. 12.0 parts of ethylene glycol bisanhydrotrimellitate was added to 100 parts of this polyester polyurethane polyol, reacted at 180°C for about 2 hours, and then diluted with EA until the solid content concentration was 50%. A solution of partially acid-modified polyester polyol B1 having a molecular weight of 9,000 and an acid value of 30.3 mgKOH/g was obtained.

[Synthesis Example 2-2] (Polyester polyol B2)
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 were placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank, and a nitrogen gas introduction pipe. The temperature was raised to 250° C. while stirring under a nitrogen stream to carry out an esterification reaction. After the reaction was continued until a predetermined amount of water was distilled out and 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 EA until the solid content concentration was 50%, resulting in a number average molecular weight of 2,000, A solution of partially acid-modified polyester polyol B2 having an acid value of 23.5 mgKOH/g was obtained.

[Synthesis Example 2-3] (Polyester polyol B3)
188 parts of ethylene glycol, 316 parts of neopentyl glycol, 179 parts of 1,6-hexanediol, 315 parts of terephthalic acid, and isophthalic acid were added to a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank, and a nitrogen gas introduction pipe. 315 parts of acid, 64 parts of adipic acid, and 323 parts of sebacic acid were charged, and the temperature was raised to 250° C. with stirring under a nitrogen stream to perform an esterification reaction. After the reaction was continued until a predetermined amount of water was distilled out and 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. Thereafter, 8.5 parts of isophorone diisocyanate was gradually added, the reaction was carried out at 150°C for about 2 hours, and then diluted with EA until the solid content concentration reached 50%, resulting in a number average molecular weight of 7,500 and an acid value of 0 mgKOH. /g of a partially acid-modified polyester polyol B3 solution was obtained.

<Adjustment of polyisocyanate>
[Preparation Example 1] (Polyisocyanate C1)
Coronate 2785 (biuret type polyisocyanate derived from hexamethylene diisocyanate, manufactured by Tosoh Corporation) was diluted with EA to adjust the solid content concentration to 50% and NCO% = 9.6% to obtain a solution of polyisocyanate C1. Ta.

<Production of adhesive> [Production example 3-1] (Adhesive D1)
90 parts of polyester polyol B1 solution, 10 parts of polyester polyol B2 solution, and 8 parts of polyisocyanate C1 solution were blended, and EA was added to prepare an adhesive solution with a solid content concentration of 30%.

[Production Example 3-2] (Adhesive D2)
100 parts of polyester polyol B3 solution and 8 parts of polyisocyanate C1 solution were blended, and EA was added to prepare an adhesive solution with a solid content concentration of 30%.

<Manufacture of laminate>
The method for manufacturing the laminate will be described below. The primer composition and printing ink were each made using a mixed solvent of EA/IPA (mass ratio 70/30) so that the viscosity was 15 seconds (25°C, Zahn cup #3 (manufactured by Rigosha)). It was used after diluting it. Further, the thicknesses of the primer layer and the printing layer were each adjusted to about 1.5 μm.

[Manufacturing Example 4-1] (Laminated body L1)
The diluted primer composition S1 and printing ink R1 were printed on OPP (corona-treated stretched polypropylene film, thickness 20 μm) in this order using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and the mixture was heated at 50° C. By drying, a laminate L1 having a structure of base material layer (OPP)/primer layer (S1)/printing layer (R1) was obtained.

[Manufacturing Example 4-2] (Laminated body L2)
The diluted printing ink R2 was printed on OPP using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and dried at 50° C. to form the base layer (OPP)/printing layer (R2). A laminate L2 was obtained.

[Manufacturing Example 4-3] (Laminated body L3)
The diluted printing ink R1 was printed on anti-fog OPP (anti-fog treated stretched polypropylene film, thickness 20 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, dried at 50 ° C. A laminate L3 having a material layer (anti-fog OPP)/printing layer (R1) configuration was obtained.

[Manufacturing Example 4-4] (Laminated body L4)
The diluted primer composition S1 and printing ink R1 were printed on OPP in this order using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and dried at 50°C to form OPP/S1/R1. A laminate having the following structure was obtained.
Next, adhesive D1 was applied onto the printed layer of the obtained laminate using a dry laminating machine so that the film thickness after drying became approximately 3 μm, and after drying, CPP (unstretched polypropylene film, thickness 30 μm) was applied. By laminating them together, a laminate L4 having a structure of base material layer (OPP)/primer layer (S1)/printing layer (R1)/adhesive layer (D1)/base material layer (CPP) was obtained.

[Manufacturing Example 4-5] (Laminated body L5)
Adhesive D1 was applied to OPP using a dry laminating machine so that the film thickness after drying was approximately 3 μm, and then it was laminated with CPP to form a base layer (OPP)/adhesive layer (D1). A laminate L5 having a structure of /base material layer (CPP) was obtained.

[Manufacturing Example 4-6] (Laminated body L6)
Diluted printing ink R1 was printed on NY (stretched nylon film, thickness 15 μm) using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, dried at 50 ° C., and printed with the composition of NY/R1. A laminate was obtained. Next, adhesive D1 was coated and dried on the printed layer of the obtained laminate using a dry laminating machine so that the film thickness after drying became approximately 3 μm, and then LLDPE (unstretched linear low density polyethylene film) , thickness 130 μm) to obtain a laminate L6 having a structure of base material layer (NY)/print layer (R1)/adhesive layer (D1)/base material layer (LLDPE).

[Manufacturing Example 4-7] (Laminated body L7)
The diluted primer composition S1 and printing ink R1 were printed on OPP in this order using a gravure printing machine equipped with a gravure plate with a plate depth of 30 μm, and dried at 50°C to form OPP/S1/R1. A laminate having the following structure was obtained.
Next, adhesive D2 was applied onto the printed layer of the obtained laminate using a dry laminating machine so that the film thickness after drying was approximately 3 μm, and VMCPP (aluminum vapor deposited unstretched polypropylene film, thickness: 25 μm) to obtain a laminate L7 having a structure of base material layer (OPP)/primer layer (S1)/printing layer (R1)/adhesive layer (D2)/base material layer (VMCPP).

Abbreviations in Table 1 are shown below.
OPP: Corona treated stretched polypropylene film, thickness 20μm
CPP: unstretched polypropylene film thickness 50μm
Anti-fog OPP: Anti-fog treated stretched polypropylene film, thickness 20μm
NY: Stretched nylon film, thickness 15 μm
LLDPE: Unstretched linear low-density polyethylene film, thickness 130 μm
VMCPP: aluminum evaporated unstretched polypropylene film, thickness 25 μm

<Crushing the laminate and creating fluff>
[Production Example 5-1] (Fluff F1)
The laminate L1 was crushed using a wet crushing device manufactured by Nippon Seam (a cutter mill equipped with a circular screen with a diameter of 3 mm) [Crushing device A] while flowing water at 20 ° C., and the average size was 3 mm. A fluff F1 was obtained.

[Production Examples 5-2 to 9, 19] (Fluff F2 to 9, 19)
The laminate was crushed using the same equipment and method as in Production Example 5-1, except that the laminate used was changed to the laminate listed in Table 2, to obtain Fluff F2-9 and 19. In addition, for F2 and F3, the screen size and the charging speed of the laminate were adjusted so that the fluff size became the value shown in Table 2.

[Production Example 5-10] (Fluff F10)
The fluff F1 crushed in Production Example 5-1 was cooled with cooling water at -10°C using a pulverizer (disc mill equipped with a cooling mechanism) [pulverizer B] manufactured by Nippon Coke Industries. Fluff F10 having an average size of 0.5 mm was obtained.

[Production Example 5-11 to 18] (Fluff F11 to 18)
Fluff was pulverized using the same equipment and method as in Production Example 5-10, except that the fluff used for pulverization was changed to the fluff listed in Table 2, to obtain fluff F11 to F18. In addition, for F11 and F12, the rotation speed and gap of the rotary blade were adjusted so that the size of the fluff after crushing became the value shown in Table 2.

[Manufacturing Example 5-20] (Fluff F20)
The fluff F1 crushed in Production Example 5-1 was pulverized in a liquid nitrogen atmosphere (-196°C) using a fine pulverizer (freeze pulverizer cryomill) [pulverizer C] made by Retsch, and the average size was 0. A fluff F20 having a diameter of .4 mm was obtained.

[Production Example 5-21 to 28] (Fluff F21 to 28)
Fluff was pulverized using the same equipment and method as in Production Example 5-20, except that the fluff used for pulverization was changed to the fluff listed in Table 2, to obtain Fluff F21-28. In addition, for F21 and F22, the number of shaking and the grinding time were adjusted so that the size of the fluff after grinding became the value shown in Table 2.

<Production of desorption liquid>
[Production Example 6-1] (Detachment liquid A1)
2 parts of sodium hydroxide, 0.4 parts of polyoxyethylene lauryl ether (HLB; 13.6), BYK-1650 (manufactured by BYK Chemie Japan, silicone emulsion type antifoaming agent, solid content concentration 27.5%) 0. 004 parts and 97.6 parts of water were mixed and stirred with a disper to obtain a desorbed liquid A1.

<Separation and recovery of laminate and production of recycled film>
[Example 1]
200 g of desorption liquid A1 and 40 g of fluff F1 were placed in a 500 mL stainless steel beaker, and the mixture was stirred at 70° C. and 2000 rpm for 10 minutes to separate the laminate and remove the printed layer. Thereafter, the fluff was allowed to stand for 30 minutes, and the fluff floating on the upper layer was collected and washed. Thereafter, the collected fluff was extruded at 200° C. using a single-screw extruder and subjected to a pelletizing process 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 with a thickness of 30 μm. The following evaluations were performed on the obtained recycled film.

[Examples 2 to 31, Comparative Examples 1 to 3] The laminate was separated by the same method as in Example 1, except that the type of fluff and the amount of fluff mixed at the time of detachment were changed to those listed in Table 3. Recovery and production of recycled film were performed, and the recycled film was evaluated. In addition, in Comparative Example 3, a recycled film was produced by pelletizing fluff without performing the desorption step.
In addition, in Examples 6, 7, 9, 15, 16, 18 to 20, 26, 27, and 29 to 31, base material 1 and base material 2 were each detached, but they were collected together without distinguishing them. Recycled film was evaluated. In Examples 8, 17, and 28, the nylon film of the base material 1 did not float to the upper layer and was not collected, and only the polyethylene film of the base material 2 was collected to evaluate the recycled film.

<Evaluation of recycled film>
(transmittance)
Regarding the coloring of the recycled film, total light transmittance was measured using a haze meter (manufactured by JEOL Ltd., SH7000), and evaluation was made based on the following criteria.
A (excellent): Total light transmittance is 80% or more.
B (Good): Total light transmittance is 60% or more and less than 80%.
C (Acceptable): Total light transmittance is 40% or more and less than 60%.
D (impossible): Total light transmittance is less than 40%

(Tensile strength)
A test piece with a width of 15 mm and a length of 150 mm was taken from the recycled film in the machine direction (MD) and transverse direction (TD), and was pulled at a distance between chucks of 50 mm and a pulling speed of 200 mm/min according to JIS K 7127. The strength (stress) when stretched to the maximum was measured in MD and TD, and the one with the larger value was evaluated based on the following criteria.
A (excellent): Tensile strength is 35 MPa or more.
B (Good): Tensile strength is 25 MPa or more and less than 35 MPa.
C (Acceptable): Tensile strength is 15 MPa or more and less than 25 MPa.
D (unacceptable): Tensile strength is less than 15 MPa. Examples 8 and 17 were evaluated based on the following criteria.
A (excellent): Tensile strength is 12 MPa or more.
B (Good): Tensile strength is 7 MPa or more and less than 12 MPa.
C (Acceptable): Tensile strength is 2 MPa or more and less than 7 MPa.
D (unacceptable): Tensile strength is less than 2 MPa

From the above evaluation results, the separation and recovery method of the present invention has a small fluff size, so the coating layer can be easily detached from a large amount of laminates in a short time, and the coating layer has a high quality with less redeposition. It was shown that a high-quality molding material with little coloring could be obtained because the fluff was homogeneously incorporated during melt-kneading.

Claims (8)

A step of crushing a laminate comprising at least a plastic base material and a coating layer in contact with the plastic base material into fluffs having an average size of 5 mm or less, and contacting the crushed fluffs with a desorption liquid, A method for separating and recovering a laminate, the method comprising the step of detaching the coating layer from the plastic base material,
The plastic base material is a plastic film with a thickness of 5 to 200 μm,
The laminate is a packaging material,
A method for separating and recovering a laminate, wherein the content of the laminate is 10% by mass or more based on the total mass of the desorbed liquid. The method for separating and recovering a laminate according to claim 1, further comprising a step of pulverizing into fluff having an average size of 1 mm or less after the step of crushing. 3. The method for separating and recovering a laminate according to claim 2, wherein the step of pulverizing is performed under cooling means. 4. The method for separating and recovering a laminate according to claim 3, wherein the step of pulverizing is performed under cooling means using a cryogen of 0° C. or lower. The method for separating and recovering a laminate according to claim 1, wherein the plastic base material contains polyolefin. The method for separating and recovering a laminate according to claim 1, wherein the desorbed liquid contains water and a surfactant. A method for producing a molding material, comprising the step of melt-kneading a plastic base material recovered by the method for separating and recovering a laminate according to any one of claims 1 to 6 . A method for producing a molded body, further comprising the step of thermoforming a molding material obtained by the method according to claim 7 .