WO2021230032A1 - Ink remover for recycling plastic laminate into recycled materials, ink film separation/removal method, and method of isolating and recovering separated or removed ink film - Google Patents

Abstract

The present invention relates to a method of separating or removing an ink film whereby it is possible to easily separate or remove an ink film printed on a plastic base material; relates to an ink remover that can be used in said method; and provides an ink film recovery method whereby it is possible to easily separate or remove an ink film printed on a plastic base material, and to easily recover the separated or removed ink film. The present invention is an ink film separation/removal method that is characterized by the use an ink remover that contains a nonionic surfactant and water to separate and/or remove an ink film from a plastic base material that has an ink film at a temperature of 25°C or higher.

Description

Ink cleaner used to recycle plastic laminates into recycled materials, ink film peeling / removal methods, and separation / recovery methods for peeled or removed ink films.

The present invention relates to an ink cleaning agent used to recycle a plastic laminate as a recycled raw material, an ink film peeling / removing method, and a method for separating and recovering a peeled or removed ink film.

Currently, the recycling rate for separate collection of plastic waste is 9% of the manufactured plastics worldwide. Of the 91% of plastic that became garbage, 12% was incinerated, and 79% was either landfilled or leaked into the environment (Non-Patent Document 1). One of the reasons why the recycling rate remains low is the difficulty of the separate collection system. In order to recycle plastics, it is necessary to separate and collect waste plastics in which different types of plastic materials such as polyethylene (PE) and polypropylene (PP) are integrated. However, in many plastic products such as laminated films, different types of plastic materials are adhered and laminated, so that it is difficult to separate and recover each material. Therefore, there is a strong demand for the construction of a recycling system that can easily separate and collect waste plastics.

In addition, it is difficult for recycled plastic products to return to the same product from the viewpoint of cost, and basically it deteriorates every time it is recycled, so it has to be reborn as a product with reduced quality. The reason why the quality of recycled plastic deteriorates is that ink and pigments are mixed as impurities in the plastic. However, since the surface of many plastic products is printed, it is difficult to decolorize them in the recycling process, and as a result, recycled plastic products are colored. Recycled plastics containing such pigments and inks are not only extremely low in commercial value due to coloring, but the fact is that they are only plastics that have deteriorated in physical properties due to impurities as a starting point, and are of good quality. There is also a need for a recycling method that produces recycled plastic.

To solve such a problem, Patent Document 1 provides an ink mainly composed of a high acid value resin in order to peel off the ink printed on a plastic product in an alkaline solution. It is not mentioned in the deterioration of printability. Patent Document 2 provides a method of stirring in a heated alkaline solution as a method of peeling the print layer from a plastic product, but in order to peel the print layer, a high acid value resin is used under the print layer. A release layer is essential. In these studies, high acid value resins such as fumaric acid, phthalic acid, and maleic acid are used for the ink and / or the release layer, but it is necessary to form the release layer in order to produce the laminated film, and the process It is not the best policy in terms of cost and cost.

On the other hand, in order to dissolve the paint and the resin film, Patent Document 3 uses a 5% sodium hydroxide aqueous solution as an alkaline detergent capable of cleaning the steel plate and polyoxyethylene alkyl ether as an additive. Further, Patent Documents 4 to 7 use cleaning liquids composed of an amine compound, water, and glycol ether according to their respective purposes. However, even with these illustrated cleaning agents, the ink film printed on the film intended by the present application could not be peeled off.

Science Advances 19 Jul 2017: Vol. 3, no. 7, e1700482

Japanese Unexamined Patent Publication No. 2001-031899 International Publication No. 2020/066652 Japanese Unexamined Patent Publication No. 10-280179 Japanese Unexamined Patent Publication No. 08-124033 Japanese Unexamined Patent Publication No. 08-245989 Japanese Unexamined Patent Publication No. 09-0867668 Japanese Unexamined Patent Publication No. 2006-8351

Most of the cleaning agents in the prior art are cleaning agents developed to dissolve the dry paint in the pipe or the etching resist resin, and are printed on a plastic substrate such as a film. It was not intended to strip or remove the films, and their cleaning agents had no such effect. In addition, in order to obtain high-quality recycled plastic and to reuse the cleaning agent, it is necessary to separate and recover the plastic base material and the ink film from the cleaning agent after peeling or removing the ink film. However, in most of the prior arts, since the object to be cleaned was not a plastic laminate having an ink film provided on a plastic base material, consideration was given to recovering each of the plastic base material and the peeled or removed ink film. It has not been.

Therefore, the problem to be solved by the present invention relates to a method for peeling or removing an ink film that can easily peel or remove an ink film printed on a plastic substrate, and an ink cleaning agent that can be applied to the method. Is. Further, the problem to be solved by the present invention is an ink film in which the ink film printed on the plastic substrate can be easily peeled off or removed, and the peeled or removed ink film can be easily recovered. To provide a collection method.

As a result of intensive research to solve the above-mentioned problems, the present inventors easily peel or remove the ink film from the plastic substrate having the ink film in a specific cleaning agent under a constant temperature condition. I found a way.
Further, the present inventors have found a method of easily peeling and precipitating an ink film from a plastic substrate having an ink film in a specific cleaning agent under a constant temperature condition, and separating and recovering only the ink film.

In addition, the present inventors easily remove the ink film from the plastic substrate having the ink film in a specific cleaning agent under a constant temperature condition, and recover the ink agglomerates localized in the supernatant of the cleaning agent. I found a way to do it.

That is, the present invention is characterized in that an ink film is peeled off or removed from a plastic substrate having an ink film at a temperature of 25 ° C. or higher by using a nonionic surfactant and an ink cleaning agent containing water. A method for peeling / removing a film is provided.

Further, the present invention uses an ink cleaning agent having an HLB value of 12.5 or more as an ink cleaning agent used in the ink film peeling / removing method, and at a temperature of 25 ° C. or higher, an ink film is formed from a plastic substrate having an ink film. Provided is an ink film recovery method characterized by recovering the peeled ink film after peeling and removing the ink film.

Further, in the present invention, an ink cleaner having an HLB value of less than 12.5 is used as the ink cleaner used in the ink film peeling / removing method, and the ink film is formed from a plastic substrate having an ink film at a temperature of 25 ° C. or higher. Provided is a method for recovering ink agglomerates, which comprises recovering ink agglomerates localized in the supernatant of a detergent after removing the ink.

The present invention also provides an ink cleaning agent used in an ink film peeling / removing method.

According to the present invention, the ink film can be easily peeled off or removed from the plastic substrate provided with the ink film, and the single-layer film can be collected, separated and reused.

According to the present invention, the ink film can be easily separated (peeled) from the plastic base material having the ink film and settled at the same time, or the ink film can be easily removed from the plastic base material having the ink film and cleaned. Since it can be localized in the supernatant of the agent, each of the plastic substrate and the ink film can be recovered, separated and reused. Therefore, the plastic base material to which the ink does not adhere can be easily recovered, and the quality of the recycled plastic can be improved. In addition, the ink film recovery process can be facilitated, and the reuse of the cleaning agent can be simplified.

In the ink film recovery method and the ink film peeling or removal method of the present invention, a wet crushing facility capable of separating into a single layer while crushing a plastic laminate, dipping, stirring, ultrasonic waves, or the like is used to describe step 1 (step 1) described later. In the ink film peeling step), a cleaning agent containing water and a nonionic surfactant is used.

When removing an ink film from a plastic substrate, dissolving it with a solvent is the simplest and easiest method, but industrially dissolving it with a solvent requires a very high solvent cost and has an environmental load. big. As a method of removing without dissolving, the ink film can be removed by using a water-soluble organic solvent containing water as the main component of the cleaning agent. In that case, a part of the ink film is contained in the cleaning agent. It is not a simple solution because it melts and it becomes difficult to separate and recover the ink film, and it is necessary to apply the cleaning agent under the conditions of high temperature of 70 ° C or higher and long time of 30 minutes or longer. I understood.

Therefore, as a result of examining various ink cleaning agents, the present inventors have obtained an ink film even under relatively low temperature conditions of about 25 ° C. by using a nonionic surfactant and an ink cleaning agent containing water. It has been found that the ink film can be peeled off or removed from the plastic substrate.

Further, by using a nonionic surfactant having an HLB value of 12.5 or more and an ink cleaning agent containing water, the ink film can be easily separated (peeled) from the plastic substrate having the ink film and settled at the same time. It was found that the ink film can be easily recovered.

Further, by using a nonionic surfactant having an HLB value of less than 12.5 and an ink cleaning agent containing water, the ink film is agglomerated after the ink film is removed from the plastic substrate having the ink film. It has been found that it can be localized in the supernatant of the detergent as a substance, and the localized ink agglomerates can be easily recovered.

Hereinafter, specific embodiments of the present invention will be sequentially described, but the present invention is not limited to the specific examples listed below.

<Ink cleaner>
The ink cleaning agent used in the present invention can easily peel or remove the ink film from the plastic base material provided with the ink film, and the plastic base material from which the ink film has been peeled off or removed is recovered, separated and reused. Examples thereof include those containing water and nonionic surfactants.

Generally, nonionic surfactants include, for example, polyoxyalkylene alkyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and the like. Polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyglycerin fatty acid ester, sucrose fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, fatty acid alkylolamide, alkylalkanolamide, acetylene Glycol, oxyethylene adduct of acetylene glycol, polyethylene glycol polypropylene glycol block copolymer, etc. can be mentioned, among which polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, etc. Examples thereof include polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, fatty acid alkylolamide, acetylene glycol, oxyethylene adduct of acetylene glycol, and polyethylene glycol polypropylene glycol block copolymer.
In the present invention, it is preferable that the ink removing agent contains 50% by mass or more of water and 0.01% by mass to 5% by mass of a nonionic surfactant in the ink cleaning agent. The content of water in the ink cleaning agent is preferably large from the viewpoint of environmental safety and work safety, and specifically, it is preferably 60% by mass or more in the ink cleaning agent, and 70% by mass. % Or more, preferably 80% by mass, and preferably 90% by mass.

The nonionic surfactant is preferably a polyoxyalkylene surfactant containing at least one compound represented by the general formula (1).

R ^1- O- [CH _2- CH (X ¹ ) -O] n ^1- H (1)
In the general formula (1), R ¹ represents a linear or branched alkyl group or an alkenyl group or an octylphenol group, n ¹ represents an average number of added moles, and X ¹ represents a hydrogen or short chain alkyl group.

In the general formula (1), when R ¹ is a linear or branched alkyl group or an alkenyl group, the number of carbon atoms represented by R 1 is preferably 10 or more. As the number of carbon atoms exceeds 10, the ink peelability is good and preferable. The specific number of carbon atoms is a decyl group having 10 carbon atoms, a lauryl group having 12 carbon atoms, a tridecyl group having 13 carbon atoms, a myristyl group having 14 carbon atoms, a cetyl group having 16 carbon atoms, and a carbon atom. The number 18 oleyl group and stearyl group can be mentioned.

Specific products include Neugen series manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., DSK NL-Dash series, DKS-NL series, Nonion series manufactured by NOF Corporation, Emargen series manufactured by Kao Corporation, and Leox manufactured by Lion Co., Ltd. Of the series, Leocol series, Lionol series, etc., among the nonionic surfactants represented by the general formula (1) ^{, if the number of carbon atoms represented by R 1} is 10 or more, this is applicable, but the present invention is limited to this. It's not a thing.

Of the general formula (1), ^{when R 1} is an octylphenol group, octylphenol ethoxylate is preferable.
Specific products include, but are limited to, Dow Chemicals'TRITON® series, Rhodia's Igepal CA series, Shell Chemicals'Nonidet P series, and Nikko Chemicals' Nikkol OP series. is not it.

^{Further, it is preferable that n 1} in the general formula (1) is 8.0 or more. The ^{larger the value of n 1} is 8.0 or more, the better the wettability with respect to the ink film, and the better the ink peelability is preferable.

^{Further, it is preferable that X 1} in the general formula (1) is a hydrogen or a methyl group.

The HLB value of the nonionic surfactant is not particularly limited, but the HLB value will be described below separately for 12.5 or more and less than 12.5. The HLB value referred to here is a value indicating the degree of affinity of the surfactant with water and oil (organic compound insoluble in water), and is a Griffin method (HLB value = 20 × molecular weight of hydrophilic portion). It is defined by (total / molecular weight).
(Nonion-based surfactant having an HLB value of 12.5 or more)
Nonionic surfactants with an HLB value of 12.5 or higher form micelles centered on water, reduce the surface tension between the ink film and the detergent, and then wet and permeate the ink and plastic groups. It is presumed that it penetrates between the materials and pulls the ink film away from the plastic substrate.

Here, the peeling of the ink film means a state in which the ink film peeled from the plastic substrate is not dissolved in the ink cleaning agent in the ink film peeling step.
By using a nonionic surfactant having an HLB value of 12.5 or more, the ink film can be peeled off without being dissolved. Therefore, since the transparency of the cleaning agent can be maintained, it is easy to recover the plastic base material and the ink film, and when the plastic base material is recovered, the ink component and the ink solution adhere to the plastic base material. Can be prevented. Further, since the ink coating film does not dissolve, the film can be recovered in a clean state, and the cleaning agent can be reused without a special recycling process. Further, the peeled ink film is settled in the cleaning agent, so that it can be easily recovered.

In order to peel off the ink film from the laminate in a short time, a surfactant having an HLB value of 12.5 or more is used, and among the surfactants represented by the general formula (1), R ¹ is used. It is preferable to use a surfactant having 10 or more carbon atoms.

And the HLB value is 12.5 or more, and, among the nonionic surfactants represented by the general formula (1), the number of carbon atoms of R ¹ is 10 or more linear alkyl group or alkenyl branched Specific surfactants showing the group are Neugen XL-61, Neugen XL-6190, Neugen XL-70, Neugen XL-80, Neugen XL-100, Neugen XL-140, Neugen XL at Dai-ichi Kogyo Seiyaku Co., Ltd. -160, XL-400D, Neugen XL-1000, Neugen LF-60X, Neugen LF-80X, Neugen LF-100X, Neugen TDS-80, Neugen TDS-100, Neugen TDS-120, Neugen TDS-200D, Neugen TDS- 500F, Neugen TDX-80, Neugen TDX-80D, Neugen TDX-100D, Neugen TDX-120D, Neugen SD-70, Neugen SD-80, Neugen SD-110, Neugen SD-150, DKS NL-80, DKS NL- 90, DKS NL-100, DKS NL-110, DKS NL-180, DKS NL-250, DKS NL-450F, DKS NL-600F, Neugen ET-160, Neugen ET-170, Neugen ET-190, DSK Dash410, Neugen LP-80, Neugen LP-100, Neugen LP-180, Neugen ET-135, Neugen ET-165, Neugen ET-159, Neugen ET-189, Nonion K-220, Nonion K-230 manufactured by Nissui Co., Ltd. , Nonion K-2100W, Persoft NH-90C, Persoft NK-100, Persoft NK-100C, Nonion P-210, Nonion P-213, Nonion E-212, Nonion E-215, Nonion E-230, Nonion S-215, Nonion S-220, Nonion B-250, Nonion ID-206, Nonion ID-209, Dispanol TOC, Nonion HT-515, Nonion HT-518, Emargen 109P, Emargen 120, Emargen manufactured by Kao 123P, Emargen 130K, Emargen 147, Emargen 150, Emargen 220, Emargen 320P, Emargen 350, Emargen 420, Emargen 430, Emargen 709, Emargen 1108, Emargen 1118S-70, Emargen 1135S-70, Emargen 1150S-60, Emargen 4085, Emargen 2020G-HA , Emargen 2025G, manufactured by Lion, Leox CL-90, Leox CL-230, Leocol TD-90, Leocol TD-90D, Leocol TDA-90-25, Leocol TDN-90-80, Leocol TD-120, Leocol TD -200, Leocol TDA-400-75, Leocol SC-80, Leocol SC-90, Leocol SC-120, Leocol SC-150, Leocol SC-200, Leocol SC-300, Leocol SC-400 and the like can be exemplified. It is not limited to this.

And the HLB value is 12.5 or more, and, among the nonionic surfactants represented by the general formula (1), specific surfactants number of carbon atoms of R ¹ indicates a more than 10 Octylphenol groups Can be exemplified by, but is not limited to, TRITON (registered trademark) X-100 of Dow Chemical Co., Ltd.

(Nonion-based surfactant having an HLB value of less than 12.5)
Nonionic surfactants with an HLB value of less than 12.5 form micelles centered on the ink film, reduce the surface tension between the ink film and the cleaning agent, and then wet and permeate the ink and plastic. It is presumed that it penetrates between the substrates and pulls the ink film away from the plastic substrate.

Here, the removal of the ink film means a state in which the ink film removed from the plastic base material is aggregated or dispersed in the ink cleaning agent in the ink film removing step.
After removing the ink film from the plastic substrate by using a nonionic surfactant having an HLB value of less than 12.5, the ink film is localized as agglomerates or dispersions in the supernatant of the cleaning agent. Can be done. Since the supernatant liquid in which the agglomerates are collected can be easily removed, the transparency of the cleaning agent can be easily maintained. Therefore, it is easy to recover the plastic base material and the ink film, and it is possible to prevent the ink component and the ink solution from adhering to the plastic base material when the plastic base material is recovered.

In order to remove the ink film from the laminate in a short time, a surfactant having an HLB value of less than 12.5 is used, and among the surfactants represented by the general formula (1), R ¹ is used. It is preferable to use a surfactant having 10 or more carbon atoms.

Among the nonionic surfactants having an HLB value of less than 12.5 and represented by the general formula (1), a linear or branched alkyl group or alkenyl group having 10 or more carbon atoms of R1. Specific surfactants indicating the above are Neugen XL-41, Neugen LF-40X, Neugen TDS-30, Neugen TDS-50, Neugen TDS-70, Neugen TDX-50, Neugen SD- 30, Neugen SD-60, DKS NL-15, DKS NL-30, DKS NL-40, DKS NL-50, DKS NL-60, DKS NL-70, Neugen ET-83, Neugen ET-102, DSK Dash400, DSK Dash 403, DSK Dash 404, DSK Dash 408, Neugen LP-55 Neugen LP-70, Neugen ET-65, Neugen ET-95, Neugen ET-115, Neugen ET-69, Neugen ET-89, Neugen ET-109, Neugen ET -129, Neugen ET-149, manufactured by Nichiyu Co., Ltd., Nonion K-204, Persoft NK-60, Nonion P-208, Nonion P-210, Nonion E-202, Nonion E-202S, Nonion E-205, Nonion E-205S, Nonion S-202, Nonion S-207, Nonion EH-204, Nonion ID-203, Nonion HT-505, Nonion HT-507, Nonion HT-510, Nonion HT-512, manufactured by Kao Corporation Emargen 102KG, Emargen 103, Emargen 104P, Emargen 105, Emargen 106, Emargen 108, Emargen 210P, Emargen 404, Emargen 408, Emargen 409PV, Emargen 705, Emargen 707, Leox CL-30, Leox CL-40 manufactured by Lion. , Leox CL-50, Leox CL-60, Leocol NL-30C, Leocol TD-50, Leocol TD-70, Leocol SC-50, Leocol SC-70 and the like, but are not limited thereto.

Further, when the compound (a) to (c), which is preferably used in combination, which will be described later, is used in combination, the liquid temperature may be lower than 50 ° C. when the compound (a) is used in combination, or the compound (b) or the compound (c) may be used in combination. If the liquid temperature is lower than 20 ° C. when used in combination with), the effect of ink peeling or removal may be reduced. Therefore, in order to improve the peeling or removing effect of the ink at a low liquid temperature, among the polyoxyalkylene alkyl ether-based surfactants represented by the general formula (1), the number of carbon atoms represented ^{by R 1 is 10.} It is preferable to use a surfactant having an HLB value of 8.5 or less.

Further, in order to improve the peeling effect and shorten the peeling time when used in combination with the compounds (a) to (c) which are preferably used in combination, the polyoxy represented by the general formula (1) is described above. Among the alkylene alkyl ether-based surfactants, it is preferable to use a surfactant having 10 or more carbon atoms and an HLB value of 8.5 or less indicated ^{by R 1.}

Among nonionic surfactant represented by the general formula (1), and the number of carbon atoms represented by R ¹ is 10 or more, HLB value of 8.5 or less specific surfactants, first industrial Neugen TDS-30, DKS NL-15, DKS NL-30, Neugen ET-83, Neugen ET-69, Neugen ET-89, Neugen ET-109, DSK Dash400, DSK Dash403, DSK Dash404, Nissui Co., Ltd. Nonion E202, Nonion S202, Nonion HT-505, Nonion HT-507 manufactured by Kao Corporation, Emargen 102KG, Emargen 103 manufactured by Kao Corporation, and the like can be exemplified, but the present invention is not limited thereto.

These surfactants can be used alone or in combination of two or more. For example, a nonionic surfactant having an HLB value of 12.5 or more and a nonionic surfactant having an HLB value of less than 12.5 may be used in combination. The amount added is preferably in the range of 0.01 to 5% by mass, more preferably 0.1 to 2% by mass, based on the total amount of the ink cleaning agent.

(Other cleaning agents)
The cleaning agent for the ink film used in the present invention includes an inorganic base (hereinafter referred to as compound (a)), an alkylene glycol alkyl ether represented by the general formula (2) (hereinafter referred to as compound (b)), and a compound (b). It is preferable to contain any compound of a primary or secondary monoalkanolamine having a boiling point of 150 to 200 ° C. (hereinafter referred to as compound (c)). By using the nonionic surfactant and the compounds (a) to (c) in combination, the removal effect can be improved and the removal time can be shortened. Above all, it is preferable to contain the compound (a), and it is also preferable to use at least one of the compounds (b) to (c) in an appropriate combination with the compound (a).

(Compound (a))
The compound (a), that is, the inorganic base is preferably contained in an amount of 0.1 to 10% by mass based on the total amount of the ink cleaning agent. Specific examples of the inorganic base include sodium hydroxide and potassium hydroxide, and it is preferable to use an aqueous solution of these compounds. The sodium hydroxide aqueous solution and the potassium hydroxide aqueous solution are preferably an aqueous solution having a concentration of 0.1% by mass to 10% by mass, and more preferably an aqueous solution having a concentration of 0.1% by mass to 5% by mass. The pH is preferably 10 or more.

(Compound (b))
The compound (b), that is, the alkylene glycol alkyl ether represented by the general formula (2) is preferably contained in an amount of 10% by mass to 50% by mass based on the total amount of the ink cleaning agent.

R ^2- O- [CH _2- CH (X ² ) -O] n ^2- H (2)
(In the general formula (2), R ² represents an alkyl group having 3 or more carbon atoms, n ² represents an integer of 1 to 3, and X ² represents a hydrogen or methyl group.)
Among the alkylene glycol alkyl ethers represented by the general formula (2), a water-soluble alkylene glycol alkyl ether is more preferable.

Examples of the water-soluble alkylene glycol alkyl ether represented by the general formula (2) include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether, and ethylene glycol-tert. -Butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol. Examples thereof include monobutyl ether.

^{Further, when compound (b) is used, R 2} is capable of maintaining removability or removability even in a composition in which the content of water greatly exceeds 50% by mass with respect to the total amount of the ink cleaning agent. It is preferable that the alkyl group has 3 or more carbon atoms, n ² is 1 to 3, and X ² is a hydrogen or methyl group.

Specifically, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol-tert-butyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, etc. It can be exemplified. These alkylene glycol alkyl ethers can be used alone or in combination of two or more, and can also be mixed with water.

Furthermore, use the number of carbon atoms represented by R ¹ in the polyoxyalkylene alkyl ether-based surfactant represented by the Among these general formulas (1) and 10 or more, HLB value of 8.5 or less of a surfactant Ethylene glycol monopropyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol monobutyl ether, etc. Triethylene glycol monobutyl ether and propylene glycol monopropyl ether are preferable.

Further, among these, ethylene glycol mono-tert-butyl ether and propylene glycol monopropyl ether are particularly preferable from the viewpoint of environmental characteristics, flammability, and defoaming property.

(Compound (c))
The compound (c), that is, the primary to secondary monoalkanolamine having a boiling point of 150 to 200 ° C. is preferably contained in an amount of 10% by mass to 50% by mass based on the total amount of the ink cleaning agent.

Examples of the primary monoalkanolamine include monoethanolamine and 2-aminoisobutanol, and examples of the secondary monoalkanolamine include N-methylethanolamine, 2-ethylaminoethanol and isopropanolamine. However, in the primary to secondary monoalkanolamines, substances other than those exemplified can be appropriately used as long as they have a boiling point of 150 to 200 ° C. In addition, these monoalkanolamine compounds can be used alone or in combination of two or more, and can also be used by mixing with water.

(Other surfactants)
The cleaning agent for the ink film used in the present invention may contain a surfactant other than the above-mentioned nonionic surfactant. By using other surfactants in combination, the peeling or removing effect can be improved.

Other surfactants are not particularly limited, and examples thereof include amphoteric surfactants and anionic surfactants. Above all, it is preferable to use it in combination with an amphoteric surfactant.
Specifically, the amphoteric tenside is preferably a betaine-type amphoteric tenside, for example, an amphoteric interface of an alkylcarboxybetaine skeleton or an alkylamide carboxybetaine skeleton containing at least one compound represented by the general formula (1a). It is more preferable to contain an activator.

^{_{R1-R2-N + (CH}} 3) 2 CH 2 COO - (1a)
(In the general formula (1a), R1 represents hydrogen or C (= O) R3-NH- (R3 represents a linear or branched alkyl group or an alkenyl group), and R2 represents an alkylene group or an alkenylene group. .)
In the general formula (1a), R1 preferably represents a hydrogen atom.
The compound represented by the general formula (1a) is preferably an amphoteric surfactant having an alkylcarboxybetaine skeleton represented by the general formula (1a-1).

^{_{C n H 2n + 1 N +}} (CH 3) 2 CH 2 COO - (1a-1)
(In the general formula (1), n indicates the average number of added moles.)
In the general formula (1-1a), n is preferably 8 or more, preferably 10 or more, and preferably 11 or more.

Further, the amphoteric surfactant may be a surfactant represented by the following general formula (1b).

R4- (NHC ₂ H ₄ ) _nb- N (R5) ₂ (1b)
(In the general formula (1b), R4 represents a linear or branched alkyl group or an alkenyl group, nb represents an integer of 0 to 5, and R5 represents hydrogen, -CH ₂ COONa or -CH ₂ COOH. The two existing R5s may be the same or different, and at least one R5 indicates -CH ₂ COONa).
In the general formula (1b), R4 preferably represents a linear alkyl group, and the number of carbon atoms of R4 is preferably 8 or more, preferably 10 or more, and preferably 12 or more.

Specific products corresponding to the general formula (1b) include, but are not limited to, Nissan Anon LG-R, Nissan Anon LA, etc. manufactured by NOF CORPORATION.

Further, the amphoteric surfactant may be an amine oxide type surfactant represented by the following general formula (1c).

_{^{R6-N + (CH 3)}} 2 O - (1c)
(In the general formula (1c), R6 represents a linear or branched alkyl group or alkenyl group.)
In the general formula (1c), R6 preferably represents a linear alkyl group in the general formula (1b), and the carbon atom number of R4 is preferably 8 or more, and preferably 10 or more. , 12 or more is preferable.

These other surfactants can be used alone in combination with a nonionic surfactant, or can be used by mixing two or more kinds of other surfactants. The amount added is preferably in the range of 0.01 to 5% by mass, more preferably 0.1 to 2% by mass, based on the total amount of the ink cleaning agent.

(Ink cleaner temperature)
In the present invention, in order to easily peel off the ink film from the plastic base material, the printing ink is removed from the printed plastic base material at a temperature of the ink cleaning agent of 25 ° C. or higher. The temperature of the ink cleaning agent, that is, the liquid temperature is not particularly limited as long as the liquid state can be maintained, but it is usually preferable that the liquid temperature is 25 to 90 ° C. The higher the cleaning effect, the higher the liquid temperature. It is preferably 40 ° C. or higher, 50 ° C. or higher, and the more effective liquid temperature is 70 ° C. or higher, more preferably 85 ° C. or higher.

(Peeling or removal equipment)
The ink cleaning agent can quickly penetrate the ink film and swell the ink film to peel the ink film from the film, or wrap the ink film with micelles to remove the ink film from the film. Therefore, the equipment and method for peeling or removing the ink film are not particularly limited, but specifically, a device equipped with a motor with a stirring blade capable of stirring the ink cleaning agent in the container, super Examples include a device equipped with a device for generating sound waves and a device capable of vigorously shaking the entire container. In addition, when the plastic base material is crushed at the same time as the ink removal, a wet crusher, a colloidal mill, or the like can be exemplified.

(Wet crusher)
One of the examples of the wet crusher used for peeling or removing the ink film of the present invention is a wet crusher capable of simultaneously crushing, dispersing, mixing, and pumping a solid substance in a liquid. Specifically, a crusher having a mechanism for crushing a solid substance in a liquid is preferable from a shearing force and / or a frictional force, and a crusher having a mechanism for crushing and pumping a plastic base material is preferable. Examples of such a wet crusher include a wet crushing pump and a colloidal mill.

(Wet crushing pump)
The wet crushing pump used in the present invention preferably has a mechanism for crushing the solid matter with a fixed blade and a rotary blade while pumping the solid matter in the liquid, and more preferable mechanisms are a cutting blade, a crushing impeller, and the like. It is a mechanism that is crushed in three stages by combining four points of shroud ring and grid.

The plastic substrate is crushed in three stages by a wet crushing pump. The plastic substrate is roughly cut by the cutting edge of the fixed blade and the edge of the entrance of the crushing impeller of the rotary blade, and then agitated and pumped by the axial flow type crushing impeller, and some plastic substrates are shrouded with the fixed blade. It hits the blade of the ring and is cut. The laminated film that has passed through the crushing impeller is further finely crushed and stirred with the grid, pressed by the pressure impeller through the grid, and pumped to the next step.

The pumping speed is not particularly limited, but considering the peeling of the ink film and the peeling and separation efficiency when separating the plastic laminate in which the plastic base material is laminated into each layer, 0.03 m ³ / min or more is used. preferable. The upper limit of the pumping speed is not particularly limited, and even a standard operating speed of the device, for example, 1.4 m ³ / min, can sufficiently peel off the ink and separate the plastic laminate into a single layer.

The grid shape is not particularly limited. Since the grid diameter is related to the size of the laminated film after crushing, the grid diameter is preferably 0.1 to 50 mm, and more preferably 1 to 20 mm in consideration of the crushing efficiency and the size of the laminated film after crushing. ..

Specific wet crushing pumps include Husqvarna Zenoah's KD series, Nikuni's Suncutta series, Furukawa Industrial Machinery Systems'disintegrator series, Aikawa Iron Works' Incrusher series, and Sanwa Hydrotech's scatter. Can be exemplified.

(Colloidal mill)
The colloidal mill used in the present invention is a machine used to reduce the particle size in a dispersion system in which particles are suspended in a liquid. The colloid mill consists of a combination of rotor and stator, and the rotor rotates at high speed with respect to the fixed stator. It is used to reduce the particle size in the liquid due to the high levels of shear that result from high speed rotation.

The crushed part of the colloidal mill consists of a combination of a tooth-shaped truncated cone-shaped rotor and a stator, and the rotor and stator have a tapered shape that narrows as they approach the discharge port. The plastic base material is repeatedly subjected to strong shearing, compression, and impact in a ring-shaped gap that narrows as it approaches the discharge port, and is crushed.

The specific colloid mill is not particularly limited as long as it is a disperser generally called a colloid mill, but IKA's colloid mill MK series, Iwaki's WCM series, Mountech's PUC colloid mill series, and Eurotech. An example is a company's colloid.

By crushing with a cleaning agent using the wet crusher, a plastic laminate in which dissimilar plastics are laminated can be separated into a single-layer film or a plastic substrate. Further, in most cases, the plastic laminate is provided with a printing ink film for displaying the product name and the like and imparting decorativeness in addition to the adhesive. Therefore, in the plastic laminate provided with the ink film. Can more efficiently peel or remove the ink film by crushing the plastic laminate in a cleaning agent. By crushing the plastic laminate in the purifying agent in this way, it is possible to simultaneously remove the ink film provided on the plastic laminate and separate the plastic laminate into a single layer. Therefore, even in a laminated structure in which the ink film does not exist in the outermost layer and the ink film is provided between two or more types of plastic substrates, the ink film can be peeled off or removed by a simple process. For example, the most commonly used inks for plastic laminated films such as those for food packaging are gravure inks and flexographic inks, but in the wet crushing process using a cleaning agent, the printing ink film is also peeled off or removed. be able to. Further, the laminated film may be laminated with a metal foil or a thin-film film such as aluminum, but in the present invention, the metal foil or the thin-film film can also be peeled off or melted.

(Recovery equipment)
The equipment and method for collecting the ink film are not particularly limited. When a nonionic surfactant having an HLB value of 12.5 or more is used, the peeled ink film precipitates in the cleaning agent, and therefore a known method for removing the precipitate can be appropriately used. Specifically, for example, a filter, a centrifuge, or the like can be used. The size of the ink film peeled off using the ink cleaning agent of the present invention varies depending on the conditions of the peeling equipment used in the ink film peeling step, but the longest part is averaged under the condition of only being immersed in the cleaning agent. Is, for example, debris of 10 μm or more, 100 μm or more, and further 1000 μm or more, and is settled. Therefore, it can be sufficiently separated even by using a filter having a coarse mesh of about 1 μm, and the sediment can be easily recovered.

On the other hand, when a nonionic surfactant having an HLB value of less than 12.5 is used, the removed ink film is localized in the upper part of the cleaning liquid as agglomerates in the supernatant liquid of the cleaning agent. A known method for removing agglomerates can be appropriately used. Specifically, for example, a filter, a centrifuge, or the like can be used. The ink agglomerates removed by using the ink cleaning agent of the present invention are fragments of 0.2 μm or more, 0.8 μm or more, and further 2 μm or more, and settle. Therefore, it can be separated even by using a filter of about 0.1 μm, and the agglomerates can be easily recovered.

The plastic base material may be recovered at the same time as the ink film is recovered, or may be recovered separately. When agglomerates of the removed ink film are formed, first, the plastic substrate is recovered using a 1000 μm filter having a coarser grain than 0.1 μm, and then the ink agglomerates are recovered. May be done.

(Plastic substrate with ink film)
The plastic substrate having an ink film used in the ink film recovery method and the ink film removing method of the present invention is not particularly limited as long as the ink film is attached to the plastic substrate. The ink film is, for example, a printing ink printed with an organic solvent type printing ink, a water-based type or an active energy ray curable type ink by using a gravure printing machine, a flexographic printing machine, an offset printing machine, an inkjet printing machine or the like. It may be an ink film of "multicolor printing" using a plurality of ink types.

The type of ink is not particularly limited, and the ink film can be peeled off regardless of the type of ink by using the ink cleaning agent of the present invention. When the ink cleaning agent of the present invention exhibits alkalinity when used in combination with sodium hydroxide, potassium hydroxide, etc., the ink contains a resin weak to alkali, for example, the resin used for the ink contains nitrocellulose, or the acid value. It is preferable to include the resin having the above, because it is easier to peel off.
The plastic base material is not particularly limited in terms of material and shape, and may be a single-layer structure or a plastic laminate in which different types of plastics are laminated. The plastic base material is preferably a film or a laminate of films. There are various types of films, for example, those made of synthetic resins such as polyethylene, polypropylene, polystyrene (styrofoam), polyethylene terephthalate, and polyvinyl chloride.

(Plastic laminate)
The plastic laminate used in the ink film recovery method and the ink film removing method of the present invention is a plastic laminate having at least two or more layers, and is an ink film, an adhesive layer, and another plastic layer on a plastic substrate. It is a laminated body in which a plurality of layers such as the above are laminated. Examples of such a laminated film include a laminated film laminated and bonded with a reactive adhesive used for food packaging and daily necessities without particular limitation, but of course, a non-reactive adhesive, for example, a thermoplastic resin. A laminated film laminated and bonded with an adhesive and a laminated film obtained by heat-sealing by an extrusion laminating method can also be separated and recovered into each single-layer film by the separation and recovery method of the present invention. Further, it may be a sheet-shaped or container-shaped laminated body.

Further, for a container such as a PET bottle, a shrink label, which is a laminated film formed in a tubular shape, is used in order to display a product name or the like and give decorativeness, and the shrink label is consumed at the time of recycling. In many cases, the PET bottle body and the shrink label are separately discarded by a person, but in the ink film recovery method and the ink film removal method of the present invention, even when the PET bottle body and the shrink label are integrated. , The ink film can be removed and recovered. In particular, when a wet powder crusher is used, the shrink label can be separated from the PET bottle body and the shrink label can be separated into each single-layer film together with ink peeling.

Laminated films laminated with a reactive adhesive often have an adhesive layer made of the reactive adhesive laminated between at least two resin film layers or a metal foil or a vapor-deposited film layer. Specifically, in the laminated film, the resin film layer is expressed as (F), the metal foil layer of the metal foil or the vapor-deposited film layer is expressed as (M), and the adhesive layer such as the reactive adhesive is expressed as (M). Expressed as (AD), the following configuration can be considered as a specific embodiment of the laminated film, but of course, the present invention is not limited to this.
(F) / (AD) / (F),
(F) / (AD) / (F) / (AD) / (F),
(F) / (AD) / (M) / (AD) / (F),
(F) / (AD) / (M),
(F) / (AD) / (M) / (F),
(F) / (AD) / (F) / (AD) / (M) / (AD) / (F),
(F) / (AD) / (M) / (AD) / (F) / (AD) / (F),
(M) / (AD) / (M),
(M) / (AD) / (F) / (AD) / (M),
(AD) / (F) / (AD) / (M),
(AD) / (F) / (AD) / (F) / (AD), etc.

The laminated film may further have a paper layer, an oxygen absorption layer, an anchor coat layer, and the like.

The plastic laminate used in the ink film recovery method and the ink film cleaning method of the present invention has a structure in which the ink film is provided in the resin film layer, but the place where the ink film is provided is not particularly limited. For example, the ink film may be provided on the outermost layer of the laminated film, or may be between the resin film layer (F) and the adhesive layer (AD). If an ink layer is provided between the resin film layer (F) and the adhesive layer (AD) (backprinting), it can be combined with a wet crushing process to separate the laminate into a single layer and peel or remove the ink layer. Can be done efficiently at the same time.

The resin film layer (F) functions as a base film layer (F1), a sealant layer (F2) that serves as a heat seal site when forming a packaging material, and the like, when classified according to the required roles.

For example, as the resin film to be the base film layer (F1), for example, a polyolefin-based film such as low-density polyethylene, high-density polyethylene, linear low-density polyethylene, OPP (biaxially stretched polypropylene), and CPP (non-stretched polypropylene). Polyester-based films such as polyethylene terephthalate (PET) and polybutylene terephthalate; polyamide-based films such as nylon 6, nylon 6,6 and methaxylene adipamide (N-MXD6); biodegradable films such as polylactic acid; poly Acrylonitrile-based film; Poly (meth) acrylic-based film; Polystyrene-based film; Polycarbonate-based film; Ethylene-vinyl acetate copolymer saponified (EVOH) -based film; Polyvinyl alcohol-based film; K-coat of polyvinylidene chloride, etc. Examples include films containing these pigments. A transparent vapor-deposited film in which alumina or silica is vapor-deposited on these films may also be used.

In addition, various surface treatments such as flame treatment, corona discharge treatment, or chemical treatment such as a primer may be performed on the surface of the film material.

Examples of the flexible polymer film to be the sealant layer (F2) include polyethylene films, polypropylene films, polyolefin films such as ethylene-vinyl acetate copolymers, ionomer resins, EAA resins, EMAA resins, EMA resins, EMMA resins, and raw materials. A film made of a decomposed resin or the like is preferable. Generic names include CPP (unstretched polypropylene) film, VMCPP (aluminum vapor-deposited unstretched polypropylene film), LLDPE (linear low-density polyethylene), LDPE (low-density polyethylene), HDPE (high-density polyethylene), VMLDPE (aluminum-deposited). Non-low density polyethylene film) film, film containing these pigments and the like can be mentioned. The surface of the film may be subjected to various surface treatments such as flame treatment, corona discharge treatment, or chemical treatment such as a primer.

Examples of the metal foil layer (M) include foils of metals having excellent ductility, such as gold, silver, copper, zinc, iron, lead, tin and alloys thereof, steel, stainless steel, and aluminum.

Examples of the paper layer include natural paper and synthetic paper. The first and second sealant layers may be made of the same material as the above-mentioned sealant layer.

Other layers may contain known additives and stabilizers such as antistatic agents, non-reactive adhesive layers, easy-adhesive coatings, plasticizers, lubricants, antioxidants and the like.

The ink film recovery method and the ink film removal method of the present invention will be described in detail by describing an example of a specific embodiment.

(Step 1: Ink film removal step)
First, the plastic base material provided with the ink film is immersed in the ink cleaning agent. The soaking time is often in the range of 60 minutes or less. In the present invention, it is not necessary to completely remove the ink film from the film, and if the film is recovered in step 2 described later and there is no inconvenience in the subsequent recycling step, a certain amount of ink film is formed on the film. It may remain. Specifically, it is sufficient that 75% by mass or more of the ink film is removed from the laminated film, and it is preferable that 80% by mass or more of the ink film is removed. As long as the ink film is peeled off or removed, the immersion time may be 30 minutes or less, or 15 minutes or less.

In step 1, the number of times of immersion in the ink cleaning agent may be once or divided into several times. After the number of dipping times is performed once, the step 2 for recovering the separated film or ink film may be performed, or the number of dipping times may be performed several times and then the step 2 may be performed. Further, when a plurality of immersions are performed in step 1, the type and concentration of the ink cleaning agent may be changed. Further, known steps such as washing with water, draining, dehydration, and drying may be appropriately added between the steps.

In step 1, the above-mentioned wet crusher or ultrasonic cleaner may be used.

(Step 2-1: Recovery step of separated film and ink film)
When a nonionic surfactant having an HLB value of 12.5 or more is used in step 1, the ink film separated from the plastic substrate does not dissolve in the ink cleaning agent but remains as a residue in the ink cleaning agent and precipitates. ing. That is, in the ink cleaning agent in step 1, the peeled film and the residue such as printing ink are suspended or settled. After removing these from the cleaning liquid, they are separated and collected.

As an example of a specific method, for example, in levitation sorting, a plastic having a light specific density such as polyolefin such as polypropylene or polyethylene (floating material) and a condensed synthetic film such as polyester or nylon having a heavier specific density than polyolefin or peeling off. Sort out the mass of the ink, etc., and remove the mass.
For example, PP, PE, etc., which have a lighter specific density than water, float, and only the film or ink film, which has a heavier specific gravity than water, settles. Therefore, it is possible to easily recover only the film having a lighter specific density with a floatator or the like.

Next, the plastics recovered in the washing and dehydrating process are washed and dehydrated, and the plastics with different specific densities are separated by centrifugation. For example, it can be divided into a plastic separated product containing a vinyl chloride resin having a specific gravity of 1 or more and polyethylene terephthalate, which is submerged in water, and a plastic separated product containing an olefin resin such as polyethylene or polypropylene, which does not contain the vinyl chloride resin.

Further separation is possible by changing the specific gravity by appropriately changing the mixing ratio of the liquid used for floating separation, for example, water and an organic solvent or salt.

After rough separation and collection by specific gravity separation, advanced separation may be performed using electrostatic separation using the inherent charging characteristics of plastic.

As an example of a specific method, there is a method of separating a precharged plastic mixture by dropping it between parallel plate electrodes to which a voltage is applied. Combinations of plastics with a small difference in specific density, which are difficult to separate by specific gravity separation, can also be separated.

(Step 3-1: Recovery and reuse of cleaning solution)
The ink cleaner used in steps 1 and 2-1 is supplied to one or more of the cleaners selected from a filter, a centrifuge, and an extraneous filter in order to recover the ink cleaner. It is reused after removing the concentrate of solids and residues. While performing the ink film peeling step and the specific gravity separation step in steps 1 and 2-1 on the other hand, the cleaning agent reuse step is continuously operated to separate the concentrate of solid matter and residue from the ink cleaning agent. You can also do it.

(Step 2-2: Recovery step of separated film and ink film)
On the other hand, when a nonionic surfactant having an HLB value of less than 12.5 is used in step 1, the ink film removed from the plastic substrate does not dissolve in the ink cleaner and becomes an agglomerate in the ink cleaner. It is either localized as a supernatant liquid or suspended as agglomerates throughout the detergent. That is, in the ink cleaning agent in step 1, the peeled film and the residue such as printing ink agglomerates are suspended or localized. When the ink cleaning agent in which these are mixed is roughly filtered with a filter having a mesh of about 1 mm as it is, only the film is turbid on the filter, and the cleaning agent and the agglomerate are turbid in the filtrate.

The film on the filter is separated and collected. As an example of a specific method, for example, in levitation sorting using water, a condensation synthetic system of a plastic having a light specific gravity such as a polyolefin such as polypropylene or polyethylene (floating material) and a polyester or nylon having a heavier specific gravity than the polyolefin. A film or a mass substance such as peeled ink is sorted and the mass substance is removed. For example, PP, PE, etc., which have a lighter specific density than water, float, and only the film or ink film, which has a heavier specific gravity than water, settles. Therefore, it is possible to easily recover only the film having a lighter specific density with a floatator or the like.

Next, the plastics recovered in the washing and dehydrating process are washed and dehydrated, and the plastics with different specific densities are separated by centrifugation. For example, it can be divided into a plastic separated product containing a vinyl chloride resin having a specific gravity of 1 or more and polyethylene terephthalate, which is submerged in water, and a plastic separated product containing an olefin resin such as polyethylene or polypropylene, which does not contain the vinyl chloride resin.

Further separation is possible by changing the specific gravity by appropriately changing the mixing ratio of the liquid used for floating separation, for example, water and an organic solvent or salt.

After rough separation and collection by specific gravity separation, advanced separation may be performed using electrostatic separation using the inherent charging characteristics of plastic.

An example of a specific method is a method of separating a precharged plastic mixture by dropping it between parallel plate electrodes to which a voltage is applied. Combinations of plastics with a small difference in specific density, which are difficult to separate by specific gravity separation, can also be separated.

(Step 3-2: Recovery and reuse of cleaning agent)
The cleaning agent used in steps 1 and 2-2 in which the ink agglomerates are turbid is usually left to stand for 1 to 2 minutes, at most 10 minutes, and the ink agglomerates are localized in the supernatant of the cleaning liquid. It will become. In order to recover the ink cleaner from the localized ink agglomerates, it is supplied to one or more of the cleaners selected from a filter, a centrifuge, and an extraneous filter, and the agglomerates and dispersions are removed. It will be reused after being removed. While performing the ink film peeling step and the specific gravity separation step in steps 1 and 2-2, the cleaning agent reuse step is continuously operated to separate the solid matter and the residue concentrate from the ink cleaning agent. You can also do it.

(Step 4: Drying of plastic separated material)
After separating the various plastic separated products separated in step 2-1 or 2-2, one or more film drying selected from vacuum heating drying, hot air drying, and pressure compression drying is performed to remove residual moisture. conduct. These can be used in combination. As a pretreatment for producing recycled pellets in step 5, briquettes may be produced using a pressure compressor such as a briquette machine after or during drying of the film.

(Step 5: Preparation of recycled pellets)
The film pieces or briquettes dried in step 4 are put into the uniaxial and biaxial molding machines to prepare recycled pellets. The conditions of the kneader are not particularly limited, but it is preferable to operate at 180 to 280 ° C. in order not to significantly deteriorate the resin performance before recycling.

The ink cleaning agent used in the present invention has improved wettability to the ink film due to the presence of the nonionic surfactant. Further, it is presumed that the interface peeling is caused by acting on the interface between the ink film and the plastic base material and remarkably reducing the adhesion thereof. Since the interface is peeled off, separation and recovery can be performed efficiently in a short time. When a nonionic surfactant having an HLB value of 12.5 or higher is used as the ink cleaner, the peeled ink film is in a state of settling without being dissolved in the ink cleaner, while the HLB is used as the ink cleaner. When a nonionic surfactant having a value of less than 12.5 is used, the ink film is in a state of being aggregated and suspended without being dissolved or settled in the ink detergent. Therefore, the peeled matter or agglomerates of the ink film can be easily collected and discarded after the cleaning step, and the ink cleaning agent can be recycled and used many times.

Hereinafter, the contents and effects of the present invention will be described in more detail by way of examples. The films, printing inks, and reactive adhesives used as raw materials in each Example and Comparative Example are shown below.

(Film used for laminated film)
OPP: Biaxially stretched polypropylene film 20um
PET: Polyethylene terephthalate film 12um
CPP: Unstretched polypropylene film 35um
(Printing ink)
Solvent type front printing gravure ink INK1: DIC graphics front printing ink Glossa BM709 White Solvent type back printing gravure ink INK2: DIC graphics back printing ink Finato R794 White S
Solvent type back printing gravure ink (two-component curing type)
INK3: Fine Wrap NTV RD-2 White manufactured by DIC Graphics (reactive adhesive)
AD1: Solvent-type adhesive Dick-dry LX-401A and SP-60 two-component adhesive <Manufacturing method of laminated film>
The laminated film was produced by printing on the target film by the printing method and then laminating the target film by the laminating method. The layer structure of the film, the reactive adhesive, and the types of printing inks were determined by the combinations shown in Table 1.
The obtained laminated films "LAM1-1" to "LAM1-6" were cut into a size of 100 mm × 50 mm to obtain a test piece.

(Printing method)
For the printing inks such as gravure ink and flexo ink, each ink was spread on the film "Film 1" using a proofer to obtain "LAM1-1" to "LAM1-5" shown in Table 1.

(Laminating method)
^{A reactive adhesive "AD" is applied with a laminator to a solid content of 3 g / m 2} on the surface opposite to the color-expanded surface of the printing ink or the color-developed surface of the printing ink of the film "Film 1" in which the printing ink is spread. It was applied so as to have a film amount, and was bonded to the film "Film 2". The laminated laminated film was subjected to an aging reaction at 40 ° C. for 72 hours. The laminated film "LAM1-6" shown in Table 1 was obtained.

Table 1 shows the table structure of the laminated film. The blank indicates that there is no configuration.

<Washing process>
PRO1: Using an ultrasonic cleaner, it was immersed at 28 kHz for 5 minutes.
PRO2: Using a homodisper, the mixture was stirred at 2000 rpm for 30 minutes.

<Evaluation method>
(Peelability test)
After the laminated film is washed and dried in each cleaning step, the area of the ink peeling property of the printed part and the peeling property of the laminated film are calculated by image processing of the photograph taken with an optical microscope, and the following formula is used. Judgment was made by determining the removal rate using.

◯: 100% of the printed part is peeled off.
○ △: 75-99% of the printed part is peeled off.
Δ: 50 to 74% of the printed part is peeled off.
Δ ×: 25 to 49% of the printed part is peeled off.
X: 0 to 25% of the printed part is peeled off.

(Defoaming test)
The defoaming property was tested according to JIS K2234 8.2 Foaming property. That is, when the total amount of the ink release agent is 100, 50 mL of the compound added in an amount such that the amount of any of the compounds (a) to (c) is 1% by mass is filled in a 100 mL graduated cylinder and brought to room temperature. It was left for 30 minutes. Then, after shaking the graduated cylinder up and down strongly 100 times (about 30 seconds), the graduated cylinder was allowed to stand, and after 10 seconds, the volume of bubbles was visually read. The height (mm) of the liquid level including bubbles 10 seconds after the shaking was stopped and immediately before shaking (mm) were measured, and the defoaming property was calculated as the foaming rate.

◯: Foaming rate 0-9%.
○ △: Foaming rate is 10 to 19%.
Δ: Foaming rate 20 to 49%.
Δ ×: Foaming rate 50 to 100%.
×: Foaming rate 100% or more.
Note that ○ and ○ △ are ranges in which there is no practical problem.

(Haze measurement)
The ink remover was placed in a quartz cell, and the haze of the ink remover was measured using SH7000 manufactured by Nippon Denshoku Kogyo Co., Ltd. in accordance with JIS K7136. The haze was evaluated in the following four stages based on the measured haze.
○: Haze 0 to 5%.
〇 △: Haze 5-10%
Δ: Haze 10 to 50%.
×: Haze 50% or more <Adjustment of ink remover>
As the polyoxyalkylene alkyl ether-based surfactant containing at least one compound represented by the general formula (1), "SUR1" to "SUR5" were used as the surfactants shown in Table 2. Note that "SUR6" is a surfactant for comparative examples that does not correspond to the compound represented by the general formula (1).

In Table 2, the abbreviations and the like are as follows.
DKS NL-Dash400: DKS NL-Dash 404 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd .: DKS NL-Dash 410 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd .: Nonion EH-204 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. Ltd.) Noigen XL-41: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. Surfynol 104: Nissin chemical Co., Ltd. ^R number of carbon atoms of ^{1: R 1} i.e. straight-chain or branched-chain in the general formula (1) Refers to the number of carbon atoms of the alkyl group or alkenyl group of.

(Compound (a)) Inorganic base Sodium hydroxide was used. Hereinafter referred to as S1.

(Compound (b)) alkylene glycol alkyl ether represented by the general formula (2) The compound shown in Table 3 was used. Hereinafter, they are referred to as S2-1 to S2-7.

(Compound (c)) Monoalkanolamine The compounds shown in Table 4 were used. Hereinafter, they are referred to as S3-1 to S3-5.

Tables 5 to 11 show a table summarizing the ink release agent composition and the evaluation results.

As a result, an example using an ink release agent containing 0.01% by mass to 5% by mass of a polyoxyalkylene alkyl ether-based surfactant containing at least one compound represented by the general formula (1) is The peeling of the ink layer was easily achieved. Especially when the liquid temperature is low, R ¹ in the general formula (1) is a surfactant having a linear or branched alkyl group or alkenyl group having 10 or more carbon atoms, and an HLB value of 8.5 or less. By using the above-mentioned surfactant, the peeling of the ink layer was promoted.

When compound (a), that is, a polyoxyalkylene alkyl ether-based surfactant containing at least one compound represented by the general formula (1) is used in combination with sodium hydroxide in an amount of 1% by mass, the ink layer can be formed even at a liquid temperature of 25 ° C. It was confirmed that exfoliation was achieved. On the other hand, when the polyoxyalkylene alkyl ether-based surfactant containing at least one compound represented by the general formula (1) was not used in combination, the ink layer could not be peeled off even at a liquid temperature of 50 ° C.

As shown in Reference Examples 1 to 7, when the compound (b), that is, the alkylene glycol alkyl ether represented by the general formula (2) is used in combination, the liquid temperature is as low as 15 ° C. and R is 3 or more. , The ink layer could be peeled off.

Further, as shown in Reference Examples 8 to 10, when compound (c), that is, monoalkanolamine is used in combination, the ink layer may be peeled off when the liquid temperature is as low as 15 ° C. and when the liquid temperature is 1st or 2nd grade. did it.

Next, we examined how to recover the ink film.

(Film used for laminated film)
OPP: Biaxially stretched polypropylene film 20um
CPP: Unstretched polypropylene film 35um
VMCPP: Aluminum-deposited non-stretched polypropylene film 25um
(Printing ink)
INK21: Gravure ink made by DIC Graphics Glossa BM709 White INK22: Gravure ink made by DIC Graphics Glossa 507 Indigo S2
INK23: Gravure Ink Fine Wrap NTV White RD-2 manufactured by DIC Graphics
(Reactive adhesive)
AD21: Solvent-type adhesive Dick-dry LX-401A and SP-60 two-component adhesive (ether-based adhesive)
AD22: Solvent-free adhesive Dick dry 2K-SF-400A and HA-400B two-component adhesive (ester adhesive)
(Manufacturing method of laminated film)
The laminated film was prepared by printing on the target film by the following printing method and then laminating the target film by the following laminating method. The layer structure of the film, the reactive adhesive, and the types of printing inks were determined by the combinations shown in Table 1.

(Printing method)
For the gravure ink, which is a printing ink, each ink was spread on the film "Film 1" using a proofer.

(Laminating method)
The reactive adhesive "AD" is applied to the color-developed surface of the printing ink of the film "Film 1" on which the printing ink is spread with a laminator so that the coating film amount has a solid content of 3 g / m2, and the film "Film 2" is used. I pasted them together. The laminated laminated film was subjected to an aging reaction at 40 ° C. for 72 hours. The laminated films "LAM21" to "LAM26" shown in Table 12 were obtained. The blank indicates that the configuration does not exist.

Laminated films "LAM21" to "LAM26" were cut into a size of 2 cm x 6 cm to obtain test pieces.

(Cleaning agent temperature)
The liquid temperature of the cleaning agent used in the peeling step was 50 ° C.

(Washing process)
PRO21: A Nikuni sun cutter C125H was used and pumped at 0.1 m3 / min.
PRO22: Using an ultrasonic cleaner, immersion was performed at 28 kHz for 5 minutes.
PRO23: Using a homodisper, the mixture was stirred at 2000 rpm for 10 minutes.
PRO24: Gently soaked in detergent for 15 minutes.

(Ink cleaner)
Water, 0.3% by mass of the surfactant shown in Table 13, and 2% by mass of sodium hydroxide were mixed to prepare an ink cleaning agent.

(Ink removability from laminated film)
Results 21 in Tables 14 to 17 show the ink removal state from the laminated film. After the laminated film is washed and dried in each cleaning step, the area of the ink removal property of the printed part is calculated by image processing of the photograph taken with an optical microscope, and the ink removal rate is calculated using the following formula. Judgment was made by asking.
Ink removal rate (%) = (1-ink adhesion area after cleaning / ink adhesion area before cleaning) x 100
◯: 100% of the printed part is removed.
〇 △: 75-99% of the printed part is removed.
Δ: 50 to 74% of the printed part or the laminated part is removed.
X: 0 to 49% of the printed part or the laminated part is removed.

(Removability of ink film)
Results 22 in Tables 14 to 17 show the dissolved or peeled state of the ink film when the cleaning agent was allowed to stand for 1 hour after the peeling step. After the ink film peeling test, the cleaning agent was filtered with a total amount of 1 um to evaluate the dissolved or peeled state of the ink film.
◯: The peeled ink film is captured by a filter, and the filtrate is colorless and transparent.
X: The dissolved ink film cannot be captured by the filter, and the filtrate is colored.

For SUR27 to 29 having an HLB value of 12.5 or more, the ink film could be peeled off with LAM21 to 23 having a laminated film configuration. On the other hand, SUR21 to 26, which were less than 12.5, could not be captured by the filter in Result 2, and the filtrate was colored, so that it could not be peeled off. From this, it was found that the ink film and the ink cleaning agent can be easily recovered by using a filter because the ink film cleaning agent having an HLB value of 12.5 or more can be peeled off as a film.

SUR27 having an HLB value of 12.5 or more was able to peel off the ink film from LAM21, which is a laminated film structure, in PRO21 to 24, which are all cleaning steps, but when the liquid temperature of the cleaning agent was 20 ° C. It could not be peeled off. On the other hand, in Comparative Example 2-2, the ink film could not be peeled off even when the liquid temperature of the cleaning agent was 50 ° C. Since the ink film was not sufficiently peeled off even when the cleaning agent temperature was set to 70 ° C. in Comparative Example 2-3, the ink film cleaning agent of the present invention was used to obtain a relatively low temperature of 25 ° C. or higher. It was also found that the ink film could be peeled off in a short time of 15 minutes.

When the wet crusher used SUR27 having an HLB value of 12.5 or more, the ink film could be peeled off with LAMs 24 to 26 having a laminated film structure.

Furthermore, a method for recovering the ink film was examined.
(Film used for laminated film)
OPP: Biaxially stretched polypropylene film 20um
CPP: Unstretched polypropylene film 35um
VMCPP: Aluminum-deposited non-stretched polypropylene film 25um
(Printing ink)
INK31: Gravure ink made by DIC Graphics Glossa BM709 White INK32: Gravure ink made by DIC Graphics Glossa 507 Indigo S2
INK33: Gravure Ink Fine Wrap NTV White RD-2 manufactured by DIC Graphics

(Reactive adhesive)
AD31: Solvent-type adhesive Dick-dry LX-401A and SP-60 two-component adhesive (ether-based adhesive)
AD32: Solvent-free adhesive Dick dry 2K-SF-400A and HA-400B two-component adhesive (ester adhesive)

(Manufacturing method of laminated film)
The laminated film was prepared by printing on the target film by the following printing method and then laminating the target film by the following laminating method. The layer structure of the film, the reactive adhesive, and the types of printing inks were determined by the combinations shown in Table 1.

(Printing method)
For the gravure ink, which is a printing ink, each ink was spread on the film "Film 1" using a proofer.

(Laminating method)
The reactive adhesive "AD" is applied to the color-developed surface of the printing ink of the film "Film 1" on which the printing ink is spread with a laminator so that the coating film amount has a solid content of 3 g / m2, and the film "Film 2" is used. I pasted them together. The laminated laminated film was subjected to an aging reaction at 40 ° C. for 72 hours. The laminated films "LAM31" to "LAM36" shown in Table 18 were obtained. The blank indicates that the configuration does not exist.

Laminated films "LAM31" to "LAM36" were cut into a size of 2 cm x 6 cm to obtain test pieces.
(Cleaning agent temperature)
The liquid temperature of the cleaning agent used in the peeling step was 50 ° C.
(Washing process)
PRO31: A Nikuni sun cutter C125H was used and pumped at 0.1 m3 / min.
PRO32: Using an ultrasonic cleaner, immersion was performed at 28 kHz for 5 minutes.
PRO33: Using a homodisper, the mixture was stirred at 2000 rpm for 10 minutes.
PRO34: Gently soaked in detergent for 15 minutes.
(Ink cleaner)
Water, 0.3% by mass of the surfactant shown in Table 19, and 2% by mass of sodium hydroxide were mixed to prepare an ink cleaning agent.

(Ink removability from laminated film)
Results 31 in Tables 20 to 22 show the ink removal state from the laminated film. After the laminated film is washed and dried in each cleaning step, the area of the ink removal property of the printed part is calculated by image processing of the photograph taken with an optical microscope, and the ink removal rate is calculated using the following formula. Judgment was made by asking.
Ink removal rate (%) = (1-ink adhesion area after cleaning / ink adhesion area before cleaning) x 100
◯: 100% of the printed part is removed.
〇 △: 75-99% of the printed part is removed.
Δ: 50 to 74% of the printed part or the laminated part is removed.
X: 0 to 49% of the printed part or the laminated part is removed.

(Two-layer separation and coloring of the supernatant)
Results 32 in Tables 20 to 22 show the two-layer separation state of the cleaning agent and the coloring state of the supernatant portion when the cleaning agent was allowed to stand for 1 hour after the cleaning step. The two-layer separation state and the coloring state were evaluated in the following four stages.
〇: The supernatant is colored, the interface is clear, and it is separated into two layers.
〇 △: The supernatant is colored and the interface is slightly unclear.
Δ: The entire cleaning liquid is colored, and the interface is unclear.
X: Not separated into two layers regardless of the presence or absence of coloring.

For SURs 31 to 36 having an HLB value of less than 12.5, the ink could be localized as a coagulant in the supernatant of the cleaning liquid after the ink film was removed by LAMs 31 to 33 having a laminated film structure. On the other hand, it was found that in SUR37 to 39 having an HLB of 12.5 or more, the ink film was peeled off, but the two-layer separation of the result 32 did not occur.
An ink film cleaning agent using a nonionic surfactant having an HLB value of less than 12.5 can remove the ink film and can be localized as agglomerates in the supernatant of the cleaning liquid, and thus is a filter. It was found that the ink agglomerates can be easily recovered and the base film can be recovered by using.

SUR34 having an HLB value of less than 12.5 was able to remove the ink film from LAM1 which is a laminated film structure in PRO1 to PRO4 in all the cleaning steps, but the liquid temperature of the cleaning agent was 20 ° C. It could not be removed in Comparative Example 3-1. On the other hand, in Comparative Example 3-2 in which a surfactant having an HLB value of less than 12.5 was not used, the ink film could not be removed even when the liquid temperature of the cleaning agent was 50 ° C. Since the removal of the ink film was insufficient even when the temperature of the cleaning agent was set to 70 ° C. in Comparative Example 3-3, by using the ink film cleaning agent of the present invention, a relatively low temperature of 25 ° C. or higher was used. It was also found that the ink film could be removed in a short time of 15 minutes.

When the wet crusher used SUR34 having an HLB value of less than 12.5, the ink film could be peeled off with LAM34 to 36 having a laminated film structure.

Claims (11)

An ink film peeling / or removing an ink film from a plastic substrate having an ink film at a temperature of 25 ° C. or higher using a nonionic surfactant and an ink cleaning agent containing water. Removal method. The ink film peeling / removing method according to claim 1, wherein the nonionic surfactant is contained in the ink cleaning agent in a range of 0.01% by mass or more and 5% by mass or less, and water is contained in an amount of 50% by mass or more. .. The ink film peeling / removing method according to claim 1 or 2, wherein the HLB value of the nonionic surfactant is 12.5 or more. The ink film peeling / removing method according to claim 1 or 2, wherein the HLB value of the nonionic surfactant is less than 12.5. The ink film peeling according to any one of claims 1 to 4, wherein the nonionic surfactant is a polyoxyalkylene-based surfactant containing at least one compound represented by the general formula (1). / Removal method.
R ^1- O- [CH _2- CH (X ¹ ) -O] n ^1- H (1)
(In the general formula (1), R ¹ represents a linear or branched alkyl group or an alkenyl group or an octylphenol group, n ¹ represents an average number of added moles, and X ¹ represents a hydrogen or short chain alkyl group. ) The ink film peeling / removing method according to claim 5, which contains any of the compounds (1-1) to (1-2) as the compound represented by the general formula (1).
(1-1) In the general formula (1), when R1 is an alkyl group or an alkenyl group, the number of carbon atoms in the linear or branched chain is 10 or more.
(1-2) In the general formula (1), when R1 is octylphenol, n1 representing the average number of added moles is 8.0 or more. The ink film peeling / removing method according to any one of claims 1 to 6, wherein the ink cleaning agent contains any of the compounds (a) to (c).
(A) Inorganic base is contained in an amount of 0.1 to 10% by mass based on the total amount of the ink cleaning agent.
(B) The alkylene glycol alkyl ether represented by the general formula (2) is contained in an amount of 10% by mass to 50% by mass with respect to the total amount of the ink cleaning agent.
R ^2- O- [CH _2- CH (X ² ) -O] n ^2- H (2)
(In the general formula (2), R ² represents an alkyl group having 3 or more carbon atoms, n ² represents an integer of 1 to 3, and X ² represents a hydrogen or methyl group.)
(C) Contains 10% by mass to 50% by mass of a primary or secondary monoalkanolamine having a boiling point of 150 to 200 ° C. with respect to the total amount of the ink cleaning agent. The ink film peeling / removing method according to any one of claims 1 to 7, further comprising an amphoteric surfactant. As the ink cleaning agent used in the ink film peeling / removing method according to any one of claims 1 to 8, an ink cleaning agent having an HLB value of 12.5 or more is used, and the ink film is used at a temperature of 25 ° C. or higher. A method for recovering an ink film, which comprises removing and removing an ink film from a plastic base material having the ink, and then recovering the peeled ink film. As the ink cleaning agent used in the ink film peeling / removing method according to any one of claims 1 to 8, an ink cleaning agent having an HLB value of less than 12.5 is used, and the ink film is used at a temperature of 25 ° C. or higher. A method for recovering ink agglomerates, which comprises removing an ink film from a plastic substrate having an ink film and then recovering ink agglomerates localized in the supernatant of a detergent. An ink cleaning agent used in the ink film peeling / removing method according to any one of claims 1 to 8.