Film-forming composition for releasing, printed matter, packaging material or integrated packaging film

Abstract

To provide a film-forming composition for removing which can easily remove a printed matter provided with a liquid printing ink on a film by an alkali treatment in a usual recycling process, and to provide a printed matter, a packaging material and a film for integrated packaging using the same.SOLUTION: There are provided a film-forming composition for desorption which can be desorbed from a base material by treatment with an alkali solution and contains a non-chlorinated polyolefin resin containing no chlorine atom, a rosin-based resin, and at least one selected from a polyamide-based resin and a urethane resin, and a laminate, a packaging material or an integrated packaging film having a primer layer formed of the film-forming composition for desorption.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a detachable film-forming composition for forming a film that can be detached from a substrate by treatment with an alkaline solution, and to a printed matter, packaging material, or integrated packaging film that is suitable for recycling and that has on a substrate a coating formed from the detachable film-forming composition.

[0002] Currently, recycling of plastic packaging materials faces the issue that printed layers printed on plastic substrates do not detach during the recycling process and become mixed into the plastic, causing a deterioration in color and physical properties, thereby reducing the value of the recycled plastic. If this issue could be resolved by making it possible to remove the printed layer from the plastic substrate during the recycling process, the value of recycled plastics would increase, leading to the entry of new recyclers and the establishment of separate collection systems by local governments. Therefore, there is a need to develop a method for removing the printed layer from the substrate during the recycling process. For example, if a primer layer formed on a substrate is removable, the printed layer formed on the primer layer can also be removed. Therefore, there is also a need to develop a material for forming a removable primer layer that can be removed from the substrate.

[0003] Films used in plastic packaging materials are made from polyolefin resins such as polyethylene resins and polypropylene resins, ester resins, polystyrene resins, etc., and liquid printing inks using chlorinated polyolefin resins are known as inks that have particularly excellent adhesion to polyolefin resin films (see, for example, Patent Document 1). However, films printed with this ink have the problem that the printed layer is difficult to remove by alkaline treatment, which is typically performed in recycling processes. There is a demand for films and packaging materials that are less likely to transfer the printing ink to articles during printing, processing, or distribution, and that have a mechanism that allows the ink to be easily removed by alkaline treatment in the recycling process.

[0004] As a method for removing chlorinated polyolefin resin-based liquid printing ink by treatment with water or an alkaline aqueous solution, a removal primer composition containing a polyethyleneimine compound with an amine value of 5.0 to 25.0 mmol / g is known (see, for example, Patent Document 2). In recent years, chlorine-based resins such as chlorinated polyolefin resins have been a concern as substances that hinder packaging recycling for the following reasons (a) and (b). (a) Chlorine-based resins such as vinyl chloride can cause corrosion of equipment or piping by releasing hydrogen chloride and generating hydrochloric acid during the thermal decomposition process of recycling. (b) In thermal recycling, which reuses the energy generated when waste is incinerated, the incineration of chlorine-based resins can result in the release of environmental hormones such as dioxins. Therefore, there will be a need in the future to develop environmentally friendly inks that are free of chlorine and PVC, for example, and that allow printed materials to be produced using such inks. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-38897 [Patent Document 2] Japanese Patent Publication No. 2023-50125 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a detachable film-forming composition that enables printed matter having a liquid printing ink applied to a film to be easily detached by alkali treatment in a normal recycling process, and to provide printed matter, packaging material, and integrated packaging film using the same. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have found that a film-forming composition for detachment containing a non-chlorinated polyolefin resin containing no chlorine atoms, a rosin-based resin, and at least one selected from a polyamide-based resin and a urethane resin can solve the above-mentioned problems.

[0008] That is, the present invention provides a detachment coating-forming composition that can be detached from a substrate by treatment with an alkaline solution, the detachment coating-forming composition comprising a non-chlorinated polyolefin resin that does not contain chlorine atoms, a rosin-based resin, and at least one selected from a polyamide-based resin and a urethane resin.

[0009] The present invention also provides a laminate having a primer layer formed on a substrate from the above-described release coating-forming composition.

[0010] The present invention also provides a laminate having, on a substrate, a primer layer formed from the above-described detachable coating-forming composition, and a printed layer, in this order.

[0011] The present invention also provides a packaging material or a film for integrated packaging using the laminate described above.

[0012] The present invention also provides a recycled plastic made from a packaging material or an integrated packaging film using the laminate described above. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a detachable film-forming composition that enables printed matter having a liquid printing ink applied to a film to be easily detached by alkali treatment in a normal recycling process, and to provide printed matter, packaging material, and integrated packaging film using the same. According to the present invention, by providing a primer layer formed from a detachable coating-forming composition that has high adhesion to a film and can be easily detached by alkali treatment, the printed layer provided on the primer layer can be configured to be free of chlorine-based resins, making it possible to provide more environmentally friendly printed materials, packaging materials, and integrated packaging films, and to promote the recyclability of these materials. DETAILED DESCRIPTION OF THE INVENTION

[0014] (Desorption film forming composition) The film-forming composition for detachment of the present invention is a film-forming composition for forming a film that can be detached from a substrate by treatment with an alkaline solution, and is characterized by containing a non-chlorinated polyolefin resin that does not contain chlorine atoms, a rosin resin, and at least one selected from a polyamide resin and a urethane resin.

[0015] (non-chlorinated polyolefin resin that does not contain chlorine atoms) The non-chlorinated polyolefin resin containing no chlorine atoms used in the present invention is not particularly limited as long as it does not contain chlorine atoms, and any non-chlorinated polyolefin resin can be used. Among these, acid-modified olefin resin (A) is preferred.

[0016] The acid-modified olefin resin may be an acid-modified olefin resin which is a copolymer of an olefin monomer and an ethylenically unsaturated carboxylic acid or an ethylenically unsaturated carboxylic acid anhydride (sometimes referred to as "acid-modified olefin resin (A-1)"), or an acid-modified olefin resin which is a resin in which a polyolefin is graft-modified with an ethylenically unsaturated carboxylic acid or an ethylenically unsaturated carboxylic acid anhydride (sometimes referred to as "acid-modified olefin resin (A-2)"), and either type of acid-modified olefin resin may be used in the present invention.

[0017] (Acid-modified olefin resin (A-1), Acid-modified olefin resin (A-2)) Examples of the olefin resin having an acid group and / or an acid anhydride group include an acid-modified olefin resin (A-1) which is a copolymer of an olefin monomer and an ethylenically unsaturated carboxylic acid or an ethylenically unsaturated carboxylic acid anhydride, and an acid-modified olefin resin (A-2) which is a resin in which a polyolefin is graft-modified with an ethylenically unsaturated carboxylic acid or an ethylenically unsaturated carboxylic acid anhydride.

[0018] Examples of olefinic monomers used to prepare the acid-modified olefin resin (A-1) include olefins having 2 to 8 carbon atoms, such as ethylene, propylene, isobutylene, 1-butene, 4-methyl-1-pentene, hexene, vinylcyclohexane, etc. Among these, olefins having 2 to 8 carbon atoms are preferred because they provide particularly good adhesive strength, and ethylene, propylene, and 1-butene are more preferred, and their combined use is particularly preferred.

[0019] Examples of the ethylenically unsaturated carboxylic acid or ethylenically unsaturated carboxylic acid anhydride used in copolymerization with an olefin-based monomer include acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, maleic anhydride, 4-methylcyclohex-4-ene-1,2-dicarboxylic anhydride, bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride, 1,2,3,4,5,8,9,10-octahydronaphthalene Examples of suitable maleic anhydrides include methyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, 2-octa-1,3-diketospiro[4.4]non-7-ene, bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, maleopimaric acid, tetrahydrophthalic anhydride, methyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, methyl-norbornene-5-ene-2,3-dicarboxylic anhydride, and norborn-5-ene-2,3-dicarboxylic anhydride. Among these, maleic anhydride is particularly preferred due to its excellent reactivity with olefinic monomers, the reactivity of the resulting anhydride after copolymerization, and the low molecular weight of the compound itself, resulting in a high functional group concentration when copolymerized. These may be used alone or in combination of two or more.

[0020] To prepare the acid-modified olefin resin (A-1), in addition to the olefinic monomer, ethylenically unsaturated carboxylic acid or ethylenically unsaturated carboxylic acid anhydride, other compounds having ethylenically unsaturated groups, such as styrene, butadiene, and isoprene, may be used in combination.

[0021] Examples of polyolefins used to prepare the acid-modified olefin resin (A-2) include homopolymers and copolymers of olefins having 2 to 8 carbon atoms, and copolymers of olefins having 2 to 8 carbon atoms with other monomers. Specific examples include polyethylenes such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene resins; polypropylene; polyisobutylene; poly(1-butene); poly(4-methyl-1-pentene); polyvinylcyclohexane; α-olefin copolymers such as ethylene-propylene block copolymers, ethylene-propylene random copolymers, ethylene-1-butene copolymers, ethylene-4-methyl-1-pentene copolymers, and ethylene-hexene copolymers; ethylene-vinyl acetate copolymers; ethylene-methyl methacrylate copolymers; ethylene-vinyl acetate-methyl methacrylate copolymers; propylene-1-butene copolymers; and ethylene-propylene-1-butene copolymers. Among these, homopolymers of olefins having 2 to 8 carbon atoms and copolymers of two or more olefins having 2 to 8 carbon atoms are preferred because they provide particularly good adhesive strength, and ethylene-propylene copolymers, ethylene-1-butene copolymers, propylene-1-butene copolymers, and ethylene-propylene-1-butene copolymers are particularly preferred.

[0022] The ethylenically unsaturated carboxylic acid or ethylenically unsaturated carboxylic acid anhydride used for graft-modification with polyolefin can be the same as those used for copolymerization with olefinic monomers in the preparation of the acid-modified olefin resin (A-1) described above. Maleic anhydride is preferred because it has high reactivity of functional groups after graft-modification and also increases the functional group concentration of the graft-modified polyolefin. These can be used alone or in combination of two or more.

[0023] Specific examples of methods for reacting an ethylenically unsaturated carboxylic acid or an ethylenically unsaturated carboxylic acid anhydride with a polyolefin by graft modification include a method in which the polyolefin is melted and the ethylenically unsaturated carboxylic acid or the ethylenically unsaturated carboxylic acid anhydride (graft monomer) is added thereto to carry out a graft reaction; a method in which the polyolefin is dissolved in a solvent to form a solution and the ethylenically unsaturated carboxylic acid or the ethylenically unsaturated carboxylic acid anhydride is added thereto to carry out a graft reaction; and a method in which the polyolefin dissolved in an organic solvent is mixed with the ethylenically unsaturated carboxylic acid or the ethylenically unsaturated carboxylic acid anhydride and heated at a temperature equal to or higher than the softening temperature or melting point of the polyolefin to simultaneously carry out radical polymerization and hydrogen abstraction reaction in the molten state.

[0024] In either case, in order to efficiently graft copolymerize the graft monomer, it is preferable to carry out the graft reaction in the presence of a radical initiator. The graft reaction is usually carried out under conditions of 60 to 350°C. The proportion of the radical initiator used is usually in the range of 0.001 to 1 part by weight per 100 parts by weight of the polyolefin before modification.

[0025] As the radical initiator, organic peroxides are preferred, such as benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(peroxidebenzoate)hexyne-3, 1,4-bis(tert-butylperoxyisopropyl)benzene, lauroyl peroxide, tert-butyl peracetate, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl perbenzoate, tert-butyl perphenyl acetate, tert-butyl perisobutyrate, tert-butyl per-sec-octoate, tert-butyl perpivalate, cumyl perpivalate, and tert-butyl perdiethyl acetate. Other azo compounds such as azobisisobutyronitrile and dimethylazoisobutyrate can also be used.

[0026] The radical initiator may be selected optimally depending on the grafting reaction process, but typically, dialkyl peroxides such as dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and 1,4-bis(tert-butylperoxyisopropyl)benzene are preferably used.

[0027] When an acid-modified olefin resin (A-1) or an acid-modified olefin resin (A-2) is used as the olefin resin (A), it is preferable to use one having an acid value of 1 to 200 mgKOH / g.

[0028] The weight average molecular weight of the olefin resin (A) is preferably 40,000 or more, and in order to ensure appropriate fluidity, the weight average molecular weight of the olefin resin (A) is preferably 250,000 or less.

[0029] In the present invention, the weight average molecular weight (Mw) and number average molecular weight (Mn) are values ​​measured by gel permeation chromatography (GPC) under the following conditions.

[0030] Measuring device: Tosoh Corporation HLC-8320GPC Column: Tosoh Corporation TSKgel 4000HXL, TSKgel 3000HXL, TSKgel 2000HXL, TSKgel 1000HXL Detector: RI (differential refractometer) Data processing: Tosoh Corporation Multistation GPC-8020modelII Measurement conditions: Column temperature 40°C Solvent: Tetrahydrofuran Flow rate 0.35ml / min Standard: Monodisperse polystyrene Sample: 100 μl of tetrahydrofuran solution containing 0.2% by mass of resin solids filtered through a microfilter

[0031] The melting point of the olefin resin used in the present invention is preferably 50° C. or higher, more preferably 60° C. or higher, and preferably 100° C. or lower, more preferably 90° C. or lower.

[0032] The melting point of olefin resin is measured by DSC (differential scanning calorimetry). Specifically, the temperature is raised at 10°C / min from the final cooling temperature to the final heating temperature, then cooled at 10°C / min to the final cooling temperature to remove the thermal history, and then heated again at 10°C / min to the final heating point. The peak temperature at the second heating is taken as the melting point. The final cooling temperature is set to a temperature 50°C or more lower than the crystallization temperature, and the final heating temperature is set to a temperature 30°C or more higher than the melting point. The final cooling temperature and heating temperature are determined by trial measurements.

[0033] The olefin resin is preferably contained in an amount of 1.0 to 50.0% by mass based on the total solid content of the detachment coating-forming composition of the present invention. This range is preferable because it allows the olefin resin to be detached during treatment with an alkaline solvent while maintaining the adhesion and heat blocking resistance of the printed matter. A more preferable amount is 1.0 to 30.0% by mass. In the present invention, the "total amount of solids in the detachment coating-forming composition" refers to the non-volatile components in the composition that remain as a coating film when made into an ink coating film, and indicates the total amount of only the non-volatile components excluding volatile components.

[0034] (rosin-based resin) The rosin-based resin used in the present invention can be any rosin and / or rosin derivative commonly used in printing inks, without any particular limitation. Specifically, rosin or rosin derivatives include rosins or carboxyl group-containing derivatives thereof. Examples of rosins include gum rosin, wood rosin, tall oil rosin, disproportionated rosin, hydrogenated rosin, and polymers thereof. Examples of rosin derivatives include carboxyl group-containing derivatives such as rosin derivatives to which unsaturated carboxylic acids such as maleic acid, itaconic acid, and crotonic acid have been added.

[0035] The amount of the rosin resin added is preferably 1.0 to 70.0 mass %, more preferably 2.0 to 60.0 mass %, based on the total amount of solids in the detachment coating-forming composition of the present invention.

[0036] In the present invention, it is particularly preferable to use a rosin-modified maleic acid resin, which is a maleic acid derivative of rosin. The rosin-modified maleic acid resin used in the present invention is not particularly limited, and any known rosin-modified maleic acid resin can be used. The rosin-modified maleic acid resin preferably has an acid value of 25 mg KOH / g or more and 320 mg KOH / g or less, and particularly preferably has an acid value of 100 mg KOH / g or more and 320 mg KOH / g or less.

[0037] Examples of commercially available rosin-based resins include Marquid Nos. 1, 2, 5, 6, 8, 31, 32, 33, 34, and 3002 manufactured by Arakawa Chemical Industries, Ltd., and Harimac R-80, T-80, R-100, M-453, M-130A, 135GN, 145P, and R-120AH, and Haritac 4851, 4821, 4740, and 28JA manufactured by Harima Chemicals Co., Ltd.

[0038] (Polyamide resin) The polyamide resin used in the present invention is, for example, a thermoplastic polyamide soluble in an organic solvent, obtainable by polycondensation of a polybasic acid and a polyamine. In particular, a polyamide resin containing a reaction product of an acid component containing a polymerized fatty acid and / or a dimer acid with an aliphatic and / or aromatic polyamine is preferred, and one containing a portion of primary and secondary monoamines is even more preferred. Polybasic acids used as raw materials for polyamide resins include, but are not limited to, adipic acid, sebacic acid, azelaic acid, phthalic anhydride, isophthalic acid, suberic acid, glutaric acid, fumaric acid, pimelic acid, oxalic acid, malonic acid, succinic acid, maleic acid, terephthalic acid, 1,4-cyclohexyldicarboxylic acid, trimellitic acid, dimer acid, hydrogenated dimer acid, and polymerized fatty acid. Among these, polyamide resins containing a structure derived from dimer acid or polymerized fatty acid as the main component (50% by weight or more in the polyamide resin) are preferred. Here, polymerized fatty acid is obtained by, for example, the cyclization reaction of unsaturated fatty acid, and includes monobasic fatty acid, dimerized polymerized fatty acid (dimer acid), trimerized polymerized fatty acid, and the like. Fatty acids constituting dimer acid or polymerized fatty acid include those derived from natural oils such as soybean oil, palm oil, and rice bran oil, with those derived from oleic acid and linoleic acid being preferred. The polybasic acid may be used in combination with a monocarboxylic acid, such as acetic acid, propionic acid, lauric acid, palmitic acid, benzoic acid, or cyclohexanecarboxylic acid.

[0039] Examples of polyamines include polyamines and primary or secondary monoamines. Examples of polyamines used in polyamide resins include aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, and methylaminopropylamine, and aliphatic polyamines such as diethylenetriamine and triethylenetetramine. Examples of alicyclic polyamines include cyclohexylenediamine and isophoronediamine. Examples of aromatic aliphatic polyamines include xylylenediamine, and examples of aromatic polyamines include phenylenediamine and diaminodiphenylmethane. Examples of primary and secondary monoamines include n-butylamine, octylamine, diethylamine, monoethanolamine, monopropanolamine, diethanolamine, and dipropanolamine.

[0040] The amount of polyamide resin added is 5.0 to 50.0 mass %, preferably 10.0 to 40.0 mass %, based on the total amount of solids in the detachment coating-forming composition of the present invention.

[0041] (Polyurethane resin) The polyurethane resin used in the present invention is not particularly limited as long as it is a polyurethane resin obtained by reacting a polyol with a polyisocyanate. As the polyol, for example, various known polyols generally used in the production of polyurethane resins can be used, and one or more types may be used in combination.For example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, hexanediol, octanediol, 1,4-butynediol, 1,4-butylenediol, diethylene glycol, triethylene glycol, dipropion Saturated or unsaturated low molecular weight polyols (1) such as ethylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, and pentaerythritol; these low molecular weight polyols (1) and sebacic acid, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, and trimellitic acid. polyester polyols (2) obtained by dehydration condensation or polymerization of polycarboxylic acids such as methyl acrylate, pyromellitic acid, or their anhydrides; polyester polyols (3) obtained by ring-opening polymerization of cyclic ester compounds, for example, lactones such as polycaprolactone, polyvalerolactone, and poly(β-methyl-γ-valerolactone); polycarbonate polyols (4) obtained by reacting the low-molecular-weight polyols (1) or the like with, for example, dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, or the like; polybutadiene glycols (5); glycols (6) obtained by adding ethylene oxide or propylene oxide to bisphenol A; and acrylic polyols (7) obtained by copolymerizing, in one molecule, one or more hydroxyethyl groups, hydroxypropyl acrylate, hydroxybutyl acrylate, or the like, or the corresponding methacrylic acid derivatives, with, for example, acrylic acid, methacrylic acid, or an ester thereof.

[0042] Examples of polyisocyanates include various known aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates that are generally used in the production of polyurethane resins. For example, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1-methyl-2,4-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-2,5-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-3,5-phenylene diisocyanate, 1-ethyl-2,4-phenylene diisocyanate, 1-isopropyl-2,4-phenylene diisocyanate, 1,3-dimethyl-2,4-phenylene diisocyanate, 1,3-dimethyl-4,6-phenylene diisocyanate, 1,4-dimethyl-2,5-phenylene diisocyanate, diethylbenzene diisocyanate, diisopropylbenzene diisocyanate, 1-methyl-3,5-diethylbenzene Aromatic polyisocyanates such as zenediisocyanate, 3-methyl-1,5-diethylbenzene-2,4-diisocyanate, 1,3,5-triethylbenzene-2,4-diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate, 1-methyl-naphthalene-1,5-diisocyanate, naphthalene-2,6-diisocyanate, naphthalene-2,7-diisocyanate, 1,1-dinaphthyl-2,2'-diisocyanate, biphenyl-2,4'-diisocyanate, biphenyl-4,4'-diisocyanate, 3-3'-dimethylbiphenyl-4,4'-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, and diphenylmethane-2,4-diisocyanate;Aliphatic or alicyclic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1,3-di(isocyanatomethyl)cyclohexane, 1,4-di(isocyanatomethyl)cyclohexane, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, and 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate can be used. These polyisocyanates can be used alone or in combination of two or more. Among these, these diisocyanate compounds can be used alone or in combination of two or more.

[0043] Chain extenders can also be used. Examples of chain extenders include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, and dicyclohexylmethane-4,4'-diamine, as well as amines having a hydroxyl group in the molecule, such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine. These chain extenders can be used alone or in combination of two or more.

[0044] Monovalent active hydrogen compounds can also be used as end-capping agents for the purpose of terminating the reaction. Examples of such compounds include dialkylamines such as di-n-butylamine and alcohols such as ethanol and isopropyl alcohol. Furthermore, when it is particularly desired to introduce carboxyl groups into the polyurethane resin, amino acids such as glycine and L-alanine can be used as reaction terminators. These end-capping agents can be used alone or in combination. The weight average molecular weight of the polyurethane resin is preferably 10,000 to 100,000, and more preferably in the range of 15,000 to 80,000.

[0045] The amount of polyurethane resin added is preferably 5.0 to 50.0 mass % based on the total amount of solids in the detachment coating-forming composition of the present invention, and more preferably 10.0 to 40.0 mass %.

[0046] (Other resins) In the present invention, other resins can also be used in combination. Examples of other resins include cellulose-based resins such as cellulose, vinyl acetate-based resins, and acrylic-based resins. From the viewpoint of improving recyclability, it is preferable that the other resins do not contain chlorine-based resins such as chlorinated polyolefins. Note that a chlorine-based resin is a resin that does not contain chlorine atoms in the resin composition.

[0047] (cellulose resin) Examples of cellulose-based resins include cellulose acetate propionate, cellulose acetate butyrate, and other cellulose ester resins, nitrocellulose (also known as soluble cellulose), hydroxyalkyl cellulose, and carboxyalkyl cellulose. The cellulose ester resin preferably has an alkyl group, and examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, and a hexyl group, and the alkyl group may further have a substituent. Of the above, cellulose acetate propionate, cellulose acetate butyrate, and nitrocellulose are preferred as cellulose-based resins. Nitrocellulose is particularly preferred. The weight-average molecular weight of the cellulose-based resin is preferably 5,000 to 200,000, more preferably 10,000 to 50,000. The glass transition temperature of the cellulose-based resin is preferably 120°C to 180°C. When used in combination with the polyurethane resin (A) of the present invention, improvements in blocking resistance, scratch resistance, and other physical properties of the ink film can be expected.

[0048] Nitrocellulose (nitrocellulose) is preferably obtained by reacting native cellulose with nitric acid to replace three hydroxyl groups in the six-membered ring of the anhydroglucopyranose group in the native cellulose with nitric acid groups to form a nitric acid ester. Nitrocellulose (nitrocellulose) preferably has a nitrogen content of 10 to 13% by mass and an average degree of polymerization of 30 to 500, more preferably a nitrogen content of 10 to 13% by mass and an average degree of polymerization of 45 to 290.

[0049] When a cellulose resin is added, the amount added is, for example, 0.3 to 25.0 mass %, preferably 0.5 to 15.0 mass %, based on the total amount of solids in the detachment coating-forming composition of the present invention.

[0050] (vinyl acetate resin) Vinyl acetate resins are vinyl acetate polymers, which are homopolymers of vinyl acetate monomers, or copolymers of vinyl acetate monomers with polymerizable unsaturated monomers. Examples of unsaturated monomers include long-chain (meth)acrylic monomers, such as alkyl (meth)acrylate monomers (e.g., n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, and stearyl (meth)acrylate; hydroxyl group-containing (meth)acrylic monomers, such as 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 1,4-butanediol mono(meth)acrylate, and (poly)ethylene glycol mono(meth)acrylate; carboxyl group-containing monomers, such as (meth)acrylic acid, maleic acid, and maleic anhydride; vinyl monomers, such as styrene, acrylonitrile, and vinyl chloride; and ethylene. These may be used alone or in combination of two or more. Among these, vinyl acetate polymers and vinyl acetate-ethylene copolymers are preferred. The weight average molecular weight of the vinyl acetate resin is preferably 5,000 to 100,000, more preferably 10,000 to 70,000. When a vinyl acetate resin is added, it is contained in an amount of 0.3 to 25.0 mass %, preferably 0.5 to 15.0 mass %, based on the total solid content of the detachment coating-forming composition of the present invention.

[0051] (acrylic resin) The acrylic resin is not particularly limited as long as it is a copolymer of polymerizable monomers whose main component is a (meth)acrylic acid ester. Examples of polymerizable monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, iso-octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, iso-nonyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, and phenoxyethyl (meth)acrylate. The polymerization method is also not particularly limited, and those obtained by known methods such as bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization can be used. The weight average molecular weight of the acrylic resin is preferably 5,000 to 200,000, and more preferably in the range of 10,000 to 100,000. When an acrylic resin is added, it is contained in an amount of 0.3 to 25.0 mass %, preferably 0.5 to 15.0 mass %, based on the total amount of solids in the detachment coating-forming composition of the present invention.

[0052] (polyester resin) The polyester resin is not particularly limited as long as it is a polyester resin obtained by reacting an alcohol with a carboxylic acid using a known esterification polymerization reaction. Examples of alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-ethyl-2-butyl-1,3propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,2-pentanediol, 3-methyl-1,5-pentanediol, hexanediol, octanediol, 1,4-butynediol, 1,4-butylenediol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, pentaerythritol, 1,4-cyclohexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, spiroglycol, and isosorbide. These may be used alone or in combination of two or more. Among these, polyfunctional alcohols are preferred. Examples of carboxylic acids include formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oleic acid, linoleic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, and 1,4-cyclohexanedicarboxylic acid. These may be used alone or in combination of two or more. Among these, polyfunctional carboxylic acids are preferred. The weight average molecular weight of the polyester resin is preferably 500 to 6000, more preferably 1400 to 5500. When a polyester resin is added, it is contained in an amount of 0.3 to 25.0 mass %, preferably 0.5 to 15.0 mass %, based on the total solid content of the detachment coating-forming composition of the present invention.

[0053] (wax) In the present invention, a wax may also be contained. The wax may be any wax that is commonly used in gravure inks or flexographic inks, such as hydrocarbon waxes and amide waxes, and is not particularly limited. Examples of hydrocarbon waxes include polyethylene wax, Fischer-Tropsch wax, paraffin wax, microcrystalline wax, polypropylene wax, etc. Among these, hydrocarbon waxes including polyethylene wax and / or Fischer-Tropsch wax are preferred, and these may be used alone or in combination of two or more.

[0054] The amide wax is preferably a fatty acid amide wax (sometimes referred to as a fatty acid amide wax). Examples of fatty acid amides (sometimes referred to as fatty acid amides; hereinafter, "amide" may also be referred to as "amide") include palmitic acid amide, stearic acid amide, ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, and erucic acid amide. These may be used alone or in combination of two or more.

[0055] The wax is preferably contained in an amount of 0.05 to 40.0 mass % relative to the total solid content of the detachment coating-forming composition of the present invention, more preferably 0.1 to 35.0 mass %, and most preferably 0.2 to 30.0 mass %. In particular, when a hydrocarbon wax is added, it is preferably contained in an amount of 0.05 to 40.0 mass % relative to the total solid content of the detachment coating-forming composition of the present invention, more preferably 0.1 to 35.0 mass %, and most preferably 0.2 to 30.0 mass %. In particular, when amide wax is added, it is preferably contained in an amount of 0.05 to 40.0 mass % relative to the total solid content of the detachment coating-forming composition of the present invention, more preferably 0.1 to 35.0 mass %, and most preferably 0.2 to 30.0 mass %.

[0056] (chelating agent) In the present invention, a chelating agent may also be contained. The chelating agent is preferably a metal chelating agent. As the metal chelating agent, a titanium-based chelating agent, a zirconium-based chelating agent, or an aluminum-based chelating agent may be used. Of these, a titanium-based chelating agent is preferred. Titanium-based chelating agents are classified into alkoxides, acylates, and chelate complexes, but chelate complexes are more preferred than alkoxides and acylates as the chelating agents used in the present invention. Specific examples of chelate complexes include titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethylacetoacetate, and phosphate ester titanium complexes. The titanium ethylacetoacetate and phosphate ester titanium complexes are acetylacetone-free and therefore offer greater safety. Among these, titanium chelate complexes are preferred, with titanium tetraacetylacetonate being most preferred. The content is more preferably 0.05 to 60 mass %, and most preferably 0.5 to 40 mass %, based on the total solid content of the detachment coating-forming composition of the present invention. do.

[0057] (organic solvent) The release coating-forming composition used in the present invention can ensure fluidity and exhibit appropriate coatability by further blending an organic solvent in addition to the above-mentioned components. Such organic solvents are not particularly limited as long as they can be removed by evaporation by heating in the drying step during adhesive application, and examples thereof include aromatic organic solvents such as toluene and xylene; aliphatic organic solvents such as n-hexane and n-heptane; alicyclic organic solvents such as cyclohexane and methylcyclohexane; halogenated organic solvents such as trichloroethylene, dichloroethylene, chlorobenzene and chloroform; ketone-based solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ester-based solvents such as ethyl acetate and butyl acetate; ethanol, methanol, n-propanol, 2-propanol (isopropyl alcohol), and the like. Examples of suitable solvents include alcohol-based solvents such as diisopropyl ether, butanol, and hexanol; ether-based solvents such as diisopropyl ether, butyl cellosolve, tetrahydrofuran, dioxane, and butyl carbitol; glycol ether-based solvents such as diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, and propylene glycol monomethyl ether; and glycol ester-based solvents such as ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, and diethylene glycol monoethyl ether acetate. These may be used alone or in combination of two or more.

[0058] Even when a non-chlorine-based olefin resin, an olefin resin having an acid group or an acid anhydride group, or an olefin resin having a hydroxyl group is used as the olefin resin (A), it is preferable to contain at least one solvent selected from aromatic solvents, ketone solvents, ester solvents, and alcohol solvents, as this provides excellent solubility.

[0059] The detachment coating-forming composition of the present invention may also contain other additives such as coloring pigments, extender pigments, leveling agents, defoamers, plasticizers, infrared absorbers, ultraviolet absorbers, fragrances, and flame retardants, provided that the effects of the present invention are not impaired.

[0060] The detachment coating-forming composition of the present invention can be produced by dissolving and / or dispersing the resin or the like in an organic solvent. The viscosity of the detachment coating-forming composition produced by the above method is preferably 10 mPa·s or more and 1000 mPa·s or less, from the viewpoint of workability during composition production and printing. The above viscosity is measured at 25°C using a Tokimec Brookfield viscometer.

[0061] (Laminate) The detachment coating-forming composition of the present invention can be printed on any substrate to form a primer layer. There are no particular limitations on the method for forming the primer layer, and the primer layer can be formed, for example, by solid printing using gravure printing with a gravure printing plate such as an electronically engraved intaglio plate, or by flexographic printing with a flexographic printing plate such as a resin plate. The primer layer, which is a printed matter formed by gravure printing or flexographic printing, has a film thickness of, for example, 10 μm or less, preferably 5 μm or less.

[0062] (base material) The substrate used in the present invention is not particularly limited, and may be a paper or plastic substrate commonly used in the gravure and flexographic printing fields, or a flexible packaging substrate used in the food packaging field. Examples of paper include fine paper used for printing on packaging materials and packages for cosmetics, beverages, pharmaceuticals, toys, equipment, etc., kraft paper, pure white roll paper, glassine paper, parchment paper, Manila cardboard, white cardboard, coated paper, art paper, construction paper, thin paper, cardboard, polyethylene-coated paper, and various synthetic papers.

[0063] Examples of film substrates include films and laminates made of polyamide resins such as nylon 6, nylon 66, and nylon 46; polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate; biodegradable resins such as polyhydroxycarboxylic acids such as polylactic acid; aliphatic polyester resins such as poly(ethylene succinate) and poly(butylene succinate); thermoplastic resins such as polyolefin resins such as polypropylene and polyethylene, polyimide resins, polyarylate resins, and mixtures thereof. Among these, films made of polyethylene terephthalate (PET), polyester, polyamide, polyethylene, and polypropylene are particularly preferred. These substrate films may be unstretched or stretched, and their manufacturing method is not limited. The thickness of the substrate film is also not particularly limited, but is typically within the range of 1 to 500 μm. The printing surface of the substrate film is preferably subjected to a corona discharge treatment, and may be vapor-deposited with aluminum, silica, alumina, or the like.

[0064] It is also preferable to use a film made of a material containing biomass-derived components as the film substrate. Biomass films are commercially available from various companies, and for example, sheets such as those listed in the list of biomass-certified products listed by the Japan Organics Recycling Association can be used.

[0065] Specifically, well-known films are made from biomass-derived ethylene glycol. Biomass-derived ethylene glycol is made from ethanol (biomass ethanol) produced from biomass as a raw material. For example, biomass-derived ethylene glycol can be obtained by converting biomass ethanol into ethylene oxide by a conventionally known method to produce ethylene glycol. Alternatively, commercially available biomass ethylene glycol may be used; for example, biomass ethylene glycol commercially available from India Glycoal Limited can be suitably used.

[0066] Alternatively, products made from biomass materials are also available, classified by their biomass plastic content as specified by ISO 16620 or ASTM D6866. Radioactive carbon-14C exists in the atmosphere at a rate of 1 in 1012 particles, and this rate remains the same for atmospheric carbon dioxide, so this rate remains the same even in plants that fix this carbon dioxide through photosynthesis. Therefore, the carbon in plant-derived resins contains radioactive carbon-14C. In contrast, the carbon in fossil fuel-derived resins contains almost no radioactive carbon-14C. Therefore, by measuring the concentration of radioactive carbon-14C in the resin using an accelerator mass spectrometer, the plant-derived resin content, or biomass plastic content, can be determined. Examples of plant-derived low-density polyethylene that is a biomass plastic having a biomass plastic content of 80% or more, preferably 90% or more as specified by ISO 16620 or ASTM D6866 include products manufactured by Braskem under the trade names "SBC818," "SPB608," "SBF0323HC," "STN7006," "SEB853," and "SPB681," and films using these as raw materials can be suitably used.

[0067] For example, as an alternative to conventional polyethylene terephthalate films made from petroleum-based raw materials, films containing biomass polyesters and biomass polyethylene terephthalates, which have biomass-derived ethylene glycol as the diol unit and fossil fuel-derived dicarboxylic acids as the dicarboxylic acid units, are known. The dicarboxylic acid units of the biomass polyester are derived from fossil fuels, and aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and derivatives thereof can be used without limitation. Furthermore, the copolymer polyester may be one in which, in addition to the above diol component and dicarboxylic acid component, a copolymerization component is added as a third component, such as a bifunctional oxycarboxylic acid, or at least one polyfunctional compound selected from the group consisting of a trifunctional or higher functional polyhydric alcohol, a trifunctional or higher functional polycarboxylic acid and / or anhydride thereof, and a trifunctional or higher functional oxycarboxylic acid, in order to form a crosslinked structure.

[0068] Furthermore, for example, as an alternative to conventional polyolefin films using petroleum-based raw materials, biomass polyolefin films such as biomass polyethylene films and biomass polyethylene-polypropylene films containing polyethylene resins made from biomass-derived ethylene glycol are also known. The polyethylene resin is not particularly limited except that ethylene glycol derived from biomass is used as part of the raw material, and examples thereof include ethylene homopolymers and copolymers of ethylene and α-olefins with ethylene as the main component (ethylene-α-olefin copolymers containing 90% by mass or more of ethylene units), and these can be used alone or in combination of two or more. The α-olefin constituting the copolymer of ethylene and α-olefin is not particularly limited, and examples thereof include α-olefins having 4 to 8 carbon atoms such as 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene. Known polyethylene resins such as low-density polyethylene resin, medium-density polyethylene resin, and linear low-density polyethylene resin can be used. Among them, linear low-density polyethylene resin (LLDPE) (a copolymer of ethylene and 1-hexene, or a copolymer of ethylene and 1-octene) is preferred from the viewpoint of making it even more difficult for damage such as holes or tears to occur even when films rub against each other, and has a density of 0.910 to 0.925 g / cm 3 More preferred is a linear low density polyethylene resin in which

[0069] Films and sheets containing starch, a biomass material, or polylactic acid are also known. These can be selected and used appropriately depending on the application.

[0070] The biomass film may be a laminate of multiple biomass films, or a laminate of a conventional petroleum-based film and a biomass film. These biomass films may be unstretched or stretched, and there are no limitations on the manufacturing method. The thickness of the base film is also not particularly limited, but is usually within the range of 1 to 500 μm. The printing surface of the substrate film is preferably subjected to a corona discharge treatment, and may be vapor-deposited with aluminum, silica, alumina, or the like.

[0071] (Integrated packaging film) The release coating composition of the present invention is particularly suitable as a primer composition for heat shrinkable films used as integrated packaging films. Examples of resins used in heat-shrinkable films include one or a mixture of two or more selected from polyester resins such as polyethylene terephthalate resins and polylactic acid resins, polyolefin resins such as polyethylene resins and polypropylene resins, and thermoplastic resins such as polystyrene resins, polyvinyl chloride resins, and polyamide resins. Of these, resin films such as polyester resins, polyolefin resins, and polystyrene resins are often used from the viewpoint of shrink properties, etc. The liquid printing ink of the present invention has particularly good adhesion to polyolefin resins, so polyolefin resin films are preferred, and polyethylene resins and polypropylene resins are particularly preferred. In addition, biomass polyester resin films such as biomass polyethylene terephthalate resin films using the aforementioned biomass polyethylene terephthalate resins, etc., and biomass polyolefin resin films such as biomass polyethylene resin films using the aforementioned biomass polyethylene resins, etc., may also be used and are preferred. The heat-shrinkable film may be a single-layer film or a multi-layer film having a plurality of layers. In the case of a multi-layer film, the back surface may have a heat-sealable layer.

[0072] The thickness of the heat-shrinkable film is not particularly limited, but is preferably 5 to 120 μm, more preferably 7 to 100 μm, and particularly preferably 10 to 80 μm, from the viewpoints of strength, rigidity, shrink properties, economy, etc. The heat-shrinkable film is preferably transparent (colorless and transparent or colored and transparent), more preferably colorless and transparent, so that the printed layer of the liquid printing ink of the present invention can be seen through it.

[0073] In order to exhibit good heat shrinkability, the heat-shrinkable film is preferably stretched in at least one direction (uniaxial stretching), and particularly preferably biaxially stretched. The stretching temperature varies depending on the type of resin constituting the film, but is, for example, 60 to 130°C. The stretching ratio is preferably about 2 to 8 times in the main stretching direction in the case of a uniaxially stretched film, and about 2 to 8 times in both one direction and the other direction perpendicular to the one direction in the case of a biaxially stretched film. The stretching method that can be used includes a roll method, a tenter method, a tube method, and the like.

[0074] The heat shrinkage percentage of the heat-shrinkable film is 20% or more in the main stretching direction for a uniaxially stretched film, and 20% or more in both directions (one direction and the other direction) for a biaxially stretched film, preferably 30 to 80%, and particularly preferably 40 to 80% (heat treatment conditions: immersion in 90°C warm water for 10 seconds).For a uniaxially stretched film, the heat shrinkage percentage in the direction perpendicular to the main stretching direction is preferably -3 to 15%, more preferably -1 to 10%, and particularly preferably -1 to 5% (heat treatment conditions: same as above). The release coating composition of the present invention can be printed on biaxially oriented polypropylene film that has not been subjected to a corona discharge treatment.

[0075] (Pattern printed layer on primer layer) On the base film, a primer layer formed by solid printing of the detachment coating-forming composition of the present invention can be provided with a printed layer having characters, figures, symbols, or other desired designs printed thereon (hereinafter referred to as a design printed layer). The picture-printed layer is a layer on which letters, figures, symbols, and other desired pictures are printed. There are no particular limitations on the printing method or printing ink, and any known printing method or printing ink can be used. Printing inks using methods such as gravure printing, flexographic printing, lithographic offset printing, and inkjet recording printing are often used for the film used as the substrate. Printing inks that combine these printing methods with methods such as curing with active energy rays (UV), LEDs, and electron beams (EB), or curing with heat, are also used. Depending on the solvent used, inks may be referred to as water-based inks or organic solvent-based inks.

[0076] Specific examples include gravure printing ink and flexographic printing ink (in some industries, gravure printing ink and flexographic printing ink are sometimes referred to as liquid printing ink), ultraviolet-curable ink for lithographic offset printing, electron-beam-curable ink for lithographic offset printing, ultraviolet-curable ink for inkjet recording and printing, and electron-beam-curable ink for inkjet recording and printing.

[0077] In particular, by using the detachment coating-forming composition of the present invention as a primer layer, even printed matter printed with a known organic solvent-based liquid printing ink that uses a chlorinated polyolefin resin as a binder resin, which is often used as a printing ink for the aforementioned integrated packaging film, can be easily deinked with an alkaline solution during recycling, which is preferable.

[0078] (Publicly known organic solvent-based liquid printing ink) (organic solvent-based liquid printing ink) Organic solvent-based liquid printing inks are prepared by dispersing a mixture containing a binder resin, an organic solvent medium, a dispersant, an antifoaming agent, etc., in a disperser to obtain a pigment dispersion. To the resulting pigment dispersion, a resin, an aqueous medium, and optionally additives such as a leveling agent are added, followed by stirring and mixing. Dispersers commonly used in the production of gravure and flexographic printing inks, such as bead mills, Eiger mills, sand mills, gamma mills, and attritors, are used for production.

[0079] The viscosity of the organic solvent-based liquid printing ink, whether used as a gravure printing ink or a flexographic printing ink, is preferably in the range of 10 mPa·s or more from the viewpoint of preventing pigment sedimentation and adequate dispersion, and 1000 mPa·s or less from the viewpoint of workability during ink production and printing. The viscosity is measured at 25°C using a Tokimec B-type viscometer.

[0080] The viscosity of the ink can be adjusted by appropriately selecting the types and amounts of raw materials used, binder resin, pigment, organic solvent, etc. The viscosity of the ink can also be adjusted by adjusting the particle size and particle size distribution of the pigment in the ink.

[0081] (Creating printed materials) The organic solvent-based liquid printing ink has excellent adhesion to various substrates and can be used for printing on paper, synthetic paper, thermoplastic resin films, plastic products, steel plates, etc., and is useful as an ink for gravure printing using a gravure printing plate made by electronic engraving or the like, or for flexographic printing using a flexographic printing plate made by a resin plate or the like.

[0082] The thickness of the liquid printing ink film formed by gravure printing or flexographic printing using the organic solvent-based liquid printing ink is, for example, 10 μm or less, and preferably 5 μm or less.

[0083] (binder resin) Examples of binder resins used in the liquid printing ink of the present invention include chlorinated polyolefin resins, as well as cellulose-based resins such as nitrocellulose, cellulose acetate propionate (CAP) and cellulose acetate butyronate (CAB), polyamide-based resins, urethane-based resins, acrylic resins, vinyl chloride-based resins such as vinyl chloride-vinyl acetate copolymer resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, and polyvinyl chloride resins, polyester resins, alkyd resins, rosin-based resins, rosin-modified maleic acid resins, ketone resins, cyclized rubber, chlorinated rubber, butyral, and petroleum resins. These resins may be the same as those used in the detachment coating-forming composition described above.

[0084] (chlorinated polyolefin resin) Chlorinated polyolefin resins are resins obtained by introducing chlorine atoms into polyolefins. Examples of polyolefins that can be used include copolymers or homopolymers of α-olefin-based unsaturated hydrocarbons such as ethylene, propylene, 1-butene, and 4-methyl-1-pentene. Examples of copolymers include propylene-α-butene copolymers, ethylene-propylene copolymers, ethylene-propylene-diene copolymers, ethylene-vinyl acetate copolymers, ethylene-1-butene copolymers, polyethylene, and poly-4-methyl-1-pentene.

[0085] Chlorinated polyolefins are produced by a solution chlorination method in which polyolefins are dissolved in an organic solvent such as carbon tetrachloride and chlorinated, a method in which polyolefins are chlorinated in an aqueous suspension state, a method in which polyolefins are chlorinated in a bulk state, etc. Furthermore, the chlorinated polyolefin may be an acid-modified chlorinated polyolefin resin in which α,β-unsaturated carboxylic acid and / or its derivative and chlorine are introduced into polyolefin. Furthermore, as a method for producing the acid-modified chlorinated polyolefin, for example, a polyolefin may be acid-modified with an α,β-unsaturated carboxylic acid and / or a derivative thereof to obtain an acid-modified polyolefin, which may then be dissolved in a chlorine-containing solvent such as chloroform, and chlorine gas may be blown into the acid-modified polyolefin to introduce chlorine therein.

[0086] Examples of the α,β-unsaturated carboxylic acid and / or derivative thereof include fumaric acid, maleic acid, maleic anhydride, citraconic acid, citraconic anhydride, mesaconic acid, itaconic acid anhydride, aconitic acid, aconitic anhydride, himic anhydride, (meth)acrylic acid, and (meth)acrylic acid esters.

[0087] In liquid printing inks, the chlorinated polyolefin used is often a chlorinated polyolefin with a chlorine content of 5 to 50% by mass. A representative example of the chlorinated polyolefin is chlorinated polypropylene resin. The chlorinated polypropylene resin often has a chlorination degree (mass % of chlorine atoms in the chlorinated polypropylene resin) of 30 to 45% and a weight average molecular weight of 5,000 to 50,000. In the present invention, the aforementioned chlorinated polyolefin resin may be used as the binder resin for the printing ink, but from the viewpoint of improving recyclability, it is preferable not to use a chlorine-based resin such as a chlorinated polyolefin resin. In the present invention, the primer layer formed from the detachment coating-forming composition has excellent adhesion to the film and also has excellent adhesion to the print formed on the primer layer, so that the resin for the printing ink can be freely selected. Therefore, an environmentally friendly ink with excellent adhesion can be realized without using a chlorinated polyolefin resin, which has conventionally been used to impart adhesion.

[0088] (hardening agent) A curing agent may be used in combination with the binder resin (A). The curing agent may be any of those commonly used in organic solvent-based gravure printing inks, but the most commonly used are isocyanate-based curing agents. The amount of the isocyanate compound added is preferably in the range of 0.3 to 10.0% by mass, more preferably 1.0 to 7.0% by mass, based on the solid content of the liquid printing ink, from the viewpoint of curing efficiency.

[0089] The binder resin (A) is preferably used in an amount of 0.15 to 50% by mass, and most preferably in an amount of 1 to 40% by mass, based on the liquid printing ink.

[0090] (organic solvent) The organic solvent used in the liquid printing ink of the present invention is not particularly limited, and any known organic solvent can be used. Generally, ethyl acetate, propyl acetate, isopropanol, normal propanol, etc. are often used in view of both the hygiene during printing and the harmfulness of packaging materials.

[0091] (coloring agent) The liquid printing ink used in the present invention contains a colorant and can be used as a colorant-containing liquid printing ink for use in design printing, etc., for the purpose of imparting cosmetic properties, etc. Examples of colorants include inorganic pigments, organic pigments and dyes used in general inks, paints, recording agents, etc., with pigments being preferred.

[0092] Examples of organic pigments include soluble azo pigments, insoluble azo pigments, azo pigments, phthalocyanine pigments, halogenated phthalocyanine pigments, anthraquinone pigments, anthanthrone pigments, dianthraquinonyl pigments, anthrapyrimidine pigments, perylene pigments, perinone pigments, quinacridone pigments, thioindigo pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, azomethine azo pigments, flavanthrone pigments, diketopyrrolopyrrole pigments, isoindoline pigments, indanthrone pigments, and carbon black pigments. Other examples include carmine 6B, lake red C, permanent red 2B, disazo yellow, pyrazolone orange, carmine FB, cromophtal yellow, cromophtal red, phthalocyanine blue, phthalocyanine green, dioxazine violet, quinacridone magenta, quinacridone red, indanthrone blue, pyrimidine yellow, thioindigo bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, daylight fluorescent pigments, etc. In addition, both non-acid-treated pigments and acid-treated pigments can be used.

[0093] Examples of inorganic pigments include white inorganic pigments such as titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, lithopone, antimony white, and gypsum. Among the inorganic pigments, titanium oxide is particularly preferred. Titanium oxide exhibits a white color and is preferred in terms of coloring power, hiding power, chemical resistance, and weather resistance. From the viewpoint of printing performance, titanium oxide is preferably treated with silica and / or alumina. Examples of inorganic pigments other than white include aluminum particles, mica, bronze powder, chrome vermilion, yellow lead, cadmium yellow, cadmium red, ultramarine, Prussian blue, red iron oxide, yellow iron oxide, iron black, and zircon. Aluminum is available in powder or paste form, but is preferably used in paste form from the viewpoints of ease of handling and safety. Whether leafing or non-leafing is used is determined appropriately from the viewpoints of brightness and density.

[0094] The pigments are preferably contained in an amount sufficient to ensure the concentration and coloring strength of the liquid printing ink, i.e., 1 to 60% by mass of the total mass of the liquid printing ink, or 10 to 90% by mass in terms of the weight ratio of solids in the liquid printing ink. These pigments can be used alone or in combination of two or more.

[0095] Organic solvent-based liquid printing inks may further contain waxes, chelating crosslinking agents, extender pigments, leveling agents, antifoaming agents, plasticizers, infrared absorbers, ultraviolet absorbers, fragrances, flame retardants, etc., as required.

[0096] (Biomass liquid printing ink) In the liquid printing ink used in the present invention, it is preferable to use a liquid printing ink made from plant-derived raw materials, taking into consideration the establishment of a recycling-based society that should continue to develop (sustainability). Examples of plant-derived raw materials include cellulose resins such as cellulose acetate propionate resin and nitrocellulose; polyamide resins using dimer acids or polymerized fatty acids derived from natural oils such as soybean oil, palm oil, and rice bran oil; polycarboxylic acids such as succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dimer acid, glutaric acid, and malic acid; polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, pentylene glycol, 1,10-dodecanediol, dimer diol, and isosorbide; and polyisocyanates such as 1,5-pentamethylene diisocyanate and dimer diisocyanate. These polycarboxylic acids include succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dimer acid, glutaric acid, and malic acid; and rosin resins.

[0097] Commercially available products can also be used as biomass liquid printing inks, such as those listed by the Japan Organics Recycling Association.

[0098] Specific embodiments of the laminate of the present invention, i.e., a laminate having a primer layer formed on a substrate from the above-described detachment coating-forming composition, or a laminate having a primer layer formed on a substrate from the above-described detachment coating-forming composition and a printed layer in this order, are not limited to, but preferred examples include the following embodiment (1-A). (1-A) Base material A - primer layer - printing layer

[0099] Furthermore, the laminate of the present invention covers not only laminates having a surface-printed structure in which a printed layer is formed on the surface of the laminate, as in the above-mentioned (1-A) embodiment, but also laminates having a laminated structure in which a coating film (various layers or films) is further formed on top of the printed layer. In other words, the laminate of the present invention also covers laminates having a laminate-type structure in which another substrate (for example, substrate B) is placed on the side opposite to the side on which the substrate (for example, substrate A) is placed relative to the printed layer, and substrate A, a primer layer, a printed layer, and substrate B are laminated together. Examples of the laminate having a laminate type structure include the laminates of the following embodiments. In the examples of laminate-type structures described below, base film 1 corresponds to base material A in the present invention. However, in embodiments where base material film 1 is not present, films such as a sealant film, a metal-vapor-deposited unstretched film, or a transparent vapor-deposited stretched film may correspond to base material A in the present invention. Furthermore, base material film 2 corresponds to base material B in the present invention. In embodiments where base material film 2 is not present, films such as a sealant film, a metal-vapor-deposited unstretched film, or a transparent vapor-deposited stretched film may correspond to base material B in the present invention. In many cases, base material B refers to a film formed on the surface opposite base material A in a laminate, but in some cases base material B is not limited to a film disposed on the surface, and base material B may be present between layers, or multiple base materials B may be provided in a laminate.

[0100] In this embodiment, a primer layer is applied onto a film corresponding to the substrate A. (1-1) Base film 1 / primer layer / printing layer / adhesive layer 1 / sealant film (1-2) Base film 1 / primer layer / printing layer / adhesive layer 1 / metal-deposited unstretched film (1-3) Base film 1 / primer layer / printing layer / adhesive layer 1 / metal-deposited stretched film (1-4) Transparent vapor-deposited stretched film / primer layer / printing layer / adhesive layer 1 / sealant film (1-5) Base film 1 / primer layer / printing layer / adhesive layer 1 / base film 2 / adhesive layer 2 / sealant film (1-6) Base film 1 / primer layer / printing layer / adhesive layer 1 / metallized stretched film / adhesive layer 2 / sealant film (1-7) Base film 1 / primer layer / printing layer / adhesive layer 1 / transparent vapor-deposited stretched film / adhesive layer 2 / sealant film (1-8) Base film 1 / primer layer / printing layer / adhesive layer 1 / metal layer / adhesive layer 2 / sealant film (1-9) Base film 1 / primer layer / printing layer / adhesive layer 1 / base film 2 / adhesive layer 2 / metal layer / adhesive layer 3 / sealant film (1-10) Base film 1 / primer layer / printing layer / adhesive layer 1 / metal layer / adhesive layer 2 / base film 2 / adhesive layer 3 / sealant film

[0101] In the above embodiments (1-1) to (1-10), a primer layer may be applied to both sides of the film positioned as the intermediate layer. (2-5) Base film 1 / primer layer / printing layer / adhesive layer 1 / primer layer / base film 2 / primer layer / adhesive layer 2 / sealant film (2-6) Base film 1 / primer layer / printing layer / adhesive layer 1 / primer layer / metal-deposited stretched film / primer layer / adhesive layer 2 / sealant film (2-7) Base film 1 / primer layer / printing layer / adhesive layer 1 / primer layer / transparent vapor-deposited stretched film / primer layer / adhesive layer 2 / sealant film (2-9) Base film 1 / primer layer / printing layer / adhesive layer 1 / primer layer / base film 2 / primer layer / adhesive layer 2 / metal layer / adhesive layer 3 / sealant film (2-10) Base film 1 / primer layer / printing layer / adhesive layer 1 / metal layer / adhesive layer 2 / primer layer / base film 2 / primer layer / adhesive layer 3 / sealant film

[0102] In the above embodiments (1-1) to (1-10), (2-5) to (2-7), and (2-9) to (2-10), a primer layer may be applied to the film corresponding to substrate B (the film located on the surface opposite to substrate A). (3-1) Base film 1 / primer layer / printing layer / adhesive layer 1 / primer layer / sealant film (3-2) Base film 1 / primer layer / printing layer / adhesive layer 1 / primer layer / metal-deposited unstretched film (3-3) Base film 1 / primer layer / printing layer / adhesive layer 1 / primer layer / metal-deposited stretched film (3-4) Transparent vapor-deposited stretched film / primer layer / printing layer / adhesive layer 1 / primer layer / sealant film (3-5) Base film 1 / primer layer / printing layer / adhesive layer 1 / base film 2 / adhesive layer 2 / primer layer / sealant film (3-6) Base film 1 / primer layer / printing layer / adhesive layer 1 / metal-deposited stretched film / adhesive layer 2 / primer layer / sealant film (3-7) Base film 1 / primer layer / printing layer / adhesive layer 1 / transparent vapor-deposited stretched film / adhesive layer 2 / primer layer / sealant film (3-8) Base film 1 / primer layer / printing layer / adhesive layer 1 / metal layer / adhesive layer 2 / primer layer / sealant film (3-9) Base film 1 / primer layer / printing layer / adhesive layer 1 / base film 2 / adhesive layer 2 / metal layer / adhesive layer 3 / primer layer / sealant film (3-10) Base film 1 / primer layer / printing layer / adhesive layer 1 / metal layer / adhesive layer 2 / base film 2 / adhesive layer 3 / primer layer / sealant film (3-2-5) Base film 1 / primer layer / printing layer / adhesive layer 1 / primer layer / base film 2 / primer layer / adhesive layer 2 / primer layer / sealant film (3-2-6) Base film 1 / primer layer / printing layer / adhesive layer 1 / primer layer / metal-deposited stretched film / primer layer / adhesive layer 2 / primer layer / sealant film (3-2-7) Base film 1 / primer layer / printing layer / adhesive layer 1 / primer layer / transparent vapor-deposited stretched film / primer layer / adhesive layer 2 / primer layer / sealant film (3-2-9) Base film 1 / primer layer / printing layer / adhesive layer 1 / primer layer / base film 2 / primer layer / adhesive layer 2 / metal layer / adhesive layer 3 / primer layer / sealant film (3-2-10) Base film 1 / primer layer / printing layer / adhesive layer 1 / metal layer / adhesive layer 2 / primer layer / base film 2 / primer layer / adhesive layer 3 / primer layer / sealant film

[0103] Among the above embodiments, the primer layer on the surface of the vapor-deposited film (whether transparent or metallic, stretched or unstretched) facing the printed layer may be removed. The vapor-deposited layer may be dissolved in an alkaline solution, making it possible to remove the primer layer formed on one surface of the vapor-deposited film. In the embodiment (4-3-4) below, one surface of the vapor-deposited film is located on the surface of the laminate, so the primer layer facing the other inward surface is removed. (4-2-6) Base film 1 / primer layer / printing layer / adhesive layer 1 / metallized stretched film / primer layer / adhesive layer 2 / sealant film (4-2-7) Base film 1 / primer layer / printing layer / adhesive layer 1 / transparent vapor-deposited stretched film / primer layer / adhesive layer 2 / sealant film (4-3-4) Transparent vapor-deposited stretched film / printing layer / adhesive layer 1 / primer layer / sealant film (4-3-2-6) Base film 1 / primer layer / printing layer / adhesive layer 1 / metallized stretched film / primer layer / adhesive layer 2 / primer layer / sealant film (4-3-2-7) Base film 1 / primer layer / printing layer / adhesive layer 1 / transparent vapor-deposited stretched film / primer layer / adhesive layer 2 / primer layer / sealant film

[0104] The laminated body having a laminate type structure may have a laminate type structure in which a coating film (various layers or films) is further formed on a printed layer by extrusion lamination. In other words, the laminate of the present invention also covers laminates having a laminate-type structure in which an extrusion laminate layer is placed on the side opposite to the side on which the substrate (for example, substrate A) is placed, and substrate A, a primer layer, a printing layer, and an extrusion laminate layer are laminated together. Examples of laminates having an extrusion laminate type structure include laminates having the following embodiments: In the examples of the laminate type structure shown below, the substrate film 1 corresponds to the substrate A of the present invention.

[0105] (5-1) Base film 1 / primer layer / printing layer / extrusion lamination anchor layer / extrusion lamination layer (5-2) Base film 1 / printing layer / primer layer / extrusion lamination anchor layer / extrusion lamination layer (Recovery of base film 1 is not anticipated. Recovery of the extrusion laminate layer is anticipated.) (5-3) Base film 1 / primer layer / printing layer / primer layer / extrusion lamination anchor layer / extrusion lamination layer (Assuming recovery of base film 1 and extrusion laminate layer)

[0106] This structure involves applying a primer layer onto a film corresponding to substrate A, followed by providing an extrusion laminate layer. As shown in (5-1) and (5-2) below, other layers such as a sealant layer may be provided on the side of the extrusion laminate layer opposite to the side on which substrate film 1 is provided. The structure of the other layers is not limited to (5-1) and (5-2) below, and can be designed appropriately depending on the required properties. (5-1) Base film 1 / primer layer / printing layer / extrusion laminate anchor layer / extrusion laminate layer (5-2) Base film 1 / primer layer / printing layer / extrusion laminate anchor layer / extrusion laminate layer / adhesive layer 1 / sealant film (5-3) Base film 1 / primer layer / printing layer / extrusion laminate anchor layer / extrusion laminate layer / adhesive layer 1 / metal layer / adhesive layer 2 / sealant film

[0107] Although the above-mentioned embodiments have been given as examples of the structure of the laminate, the structure is not limited to these.

[0108] (Method for removing primer layer from substrate) The primer layer formed by the detachment coating-forming composition of the present invention can be detached (removed) from the substrate by immersion in an alkaline solution. There are no particular limitations on the alkaline substance used in the alkaline aqueous solution used to remove the primer layer in the present invention, and examples include sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), ammonia, etc. The alkaline aqueous solution is preferably NaOH or KOH. The alkaline aqueous solution can be produced by uniformly dissolving or dispersing NaOH, KOH, ammonia, or the like in water, and then adjusting the concentration or pH accordingly.

[0109] <Method for removing primer layer in the case of the laminate of the above embodiment (1-A)> Typically, the primer layer can be removed by immersing the laminate in an alkaline aqueous solution at 10°C to 100°C for 30 minutes, either at a pH of 11 or higher or at a concentration of 0.5 to 3.0% by mass, followed by rinsing and drying, which removes at least 90% of the primer layer. The pH is preferably 11.0 or higher, more preferably 13.0 or higher. The concentration is preferably a 0.5 to 3.0% by mass aqueous solution, more preferably a 1.0 to 2.5% by mass aqueous solution. The immersion temperature is preferably 100°C or lower, more preferably 90°C or lower, and even more preferably 80°C or lower. On the other hand, to prevent unintentional adhesion of an alkaline substance to the laminate, which would otherwise cause detachment of the primer layer and ultimately removal of the printed layer, it is necessary that the primer not be detached at low temperatures. Therefore, the immersion temperature is preferably 30°C or higher, more preferably 40°C or higher, and even more preferably 50°C or higher. The immersion time is preferably within 60 minutes, more preferably within 30 minutes, and even more preferably within 20 minutes. After that, when the substrate is washed with water and dried, the removal rate of the primer layer is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

[0110] <Method for removing primer layer in the case of a laminate-type laminate such as the above (1-1) embodiment> In the case of the laminate of the above-mentioned (1-1) embodiment, the primer layer is sandwiched between plastic films, and it takes a considerable amount of time for the alkaline aqueous solution to reach the primer layer. Therefore, the immersion time is longer than that of the (1-A) embodiment, but it is more preferable that delamination proceeds in a short time. The immersion time is preferably within 24 hours, more preferably within 12 hours, and even more preferably within 6 hours.

[0111] (Manufacturing method for recycled plastics) The recycled plastic of the present invention can be obtained by a known processing method for recycling waste plastics using the laminate of the present invention. An example of the processing method is shown below. Of course, the present invention is not limited to this, and various known recycled plastic processing methods can be applied.

[0112] An example of the processing method is a method for producing recycled plastics, which includes the steps of crushing the laminate of the present invention, melting and kneading the crushed pieces, and pelletizing the melted and kneaded mixture. The crusher used in the step of crushing the laminate of the present invention is not particularly limited, and any known crusher may be used. The crushed film pieces are physically blended using methods such as melt mixing, solvent cast blending, latex blending, and polymer complexing. Melt mixing is particularly common. Examples of mixing devices include tumblers, Henschel mixers, rotary mixers, super mixers, ribbon tumblers, and V-blenders. The film pieces are melt-mixed using these mixers and then pelletized. Single- or multi-screw extruders are typically used for melt mixing and pelletization. The film pieces may be fed directly into the extruder or may be compressed with or without heating before being added. In addition to these extruders, Banbury mixers, roller mixers, Ko-kneaders, blast mills, and Prabender Bloutographs can also be used, operated batchwise or continuously. Alternatively, the film pieces may be used as molding resins without melt mixing and then melt-kneaded in the heating barrel of a molding machine.

[0113] Another example of a processing method is a method for producing recycled plastics, which includes the steps of crushing the laminate of the present invention, immersing the laminate in a stripping liquid to separate and detach each layer, recovering each separated layer, melting and kneading the recovered crushed pieces, and pelletizing the melted and kneaded mixture.

[0114] As described above, the crusher used in the step of crushing the laminate of the present invention is not particularly limited as long as it is a known crusher. The crushed film pieces are immersed in a stripping solution to separate and detach the laminate into individual layers. The separation and detachment method (also simply referred to as the detachment method) is a method in which the laminate of the present invention is immersed in a stripping treatment solution to detach other layers provided on the substrate from the substrate. Note that detachment refers to the separation of the substrate from other layers by the detachment layer being dissolved or swelled by the stripping treatment solution and peeled off.

[0115] (Desorption treatment solution) The release treatment liquid may be any liquid capable of swelling and dissolving the adhesive layer, the printed layer, etc. in the laminate of the present invention, and may be appropriately selected taking into consideration the ease of release of the release layer described below. Examples of such release liquids include water, an alkaline solution, and an acidic aqueous solution. The release treatment liquid is preferably an alkaline solution containing an inorganic base, from the viewpoint of releasing materials of adhesive layers and printed layers that are commonly used in packaging materials.

[0116] (inorganic bases) Specific examples of inorganic bases include sodium hydroxide, potassium hydroxide, sodium bicarbonate, potassium bicarbonate, sodium dihydrogen carbonate, and potassium dihydrogen carbonate. These inorganic bases are contained in a concentration of 0.1 to 10% by weight, more preferably 0.1 to 5% by weight, based on the total weight of the aqueous solution. The pH is preferably 9 or higher, and more preferably 10 or higher.

[0117] (surfactant) The detachment treatment solution may contain a surfactant. The surfactant is not particularly limited and any known surfactant can be used, for example, anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, etc., and among these, anionic surfactants, nonionic surfactants, and amphoteric surfactants are preferred.

[0118] Examples of anionic surfactants include alkylbenzenesulfonates, alkylphenylsulfonates, alkylnaphthalenesulfonates, higher fatty acid salts, sulfate ester salts of higher fatty acid esters, sulfonates of higher fatty acid esters, sulfate ester salts and sulfonates of higher alcohol ethers, higher alkyl sulfosuccinates, polyoxyethylene alkyl ether carboxylates, polyoxyethylene alkyl ether sulfates, alkyl phosphates, and polyoxyethylene alkyl ether phosphates. Specific examples of these include dodecylbenzenesulfonate, isopropylnaphthalenesulfonate, monobutylphenylphenol monosulfonate, monobutylbiphenylsulfonate, and dibutylphenylphenol disulfonate.

[0119] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyglycerin fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene fatty acid amides, fatty acid alkylolamides, alkylalkanolamides, acetylene glycol, oxyethylene adducts of acetylene glycol, and polyethylene glycol polypropylene glycol block copolymers. Of these, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid alkylolamides, acetylene glycol, oxyethylene adducts of acetylene glycol, and polyethylene glycol polypropylene glycol block copolymers are preferred.

[0120] Other surfactants that can be used include silicone surfactants such as polysiloxane oxyethylene adducts; fluorine-based surfactants such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and oxyethylene perfluoroalkyl ethers; and biosurfactants such as spiculisporic acid, rhamnolipid, and lysolecithin.

[0121] These surfactants can be used alone or in combination of two or more. When a surfactant is added, the amount added is preferably in the range of 0.001 to 2 mass %, more preferably 0.001 to 1.5 mass %, and even more preferably 0.01 to 1 mass %, based on the total amount of the desorption treatment solution.

[0122] (Water-soluble organic solvent) The desorption treatment liquid may contain a water-soluble organic solvent. Examples of the water-soluble organic solvent include water-soluble alcohols and water-soluble glycol ether organic solvents. Specific examples include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (cellosolve), ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol dibutyl ether, diethylene glycol monomethyl ether (methyl carbitol), diethylene glycol dimethyl ether, diethylene glycol monoethyl ether (carbitol), diethylene glycol diethyl ether (diethyl carbitol), diethylene glycol monobutyl ether (butyl carbitol), diethylene glycol dibutyl ether, triethylene glycol monomethyl ether (methyl carbitol), diethylene glycol monoethyl ether (carbitol), diethylene glycol diethyl ether (diethyl carbitol), diethylene glycol monobutyl ether (butyl carbitol), diethylene glycol dibutyl ether, triethylene glycol monomethyl ether (methyl carbitol), diethylene glycol monoethyl ether (methyl carbitol), diethylene glycol monoethyl ether (diethyl carbitol), diethylene glycol monobutyl ether (butyl carbitol), diethylene glycol dibutyl ether, triethylene glycol monomethyl ether (methyl carbitol), diethylene glycol monoethyl ether (methyl carbitol), diethylene glycol monoethyl ether (diethyl carbitol), diethylene glycol monoethyl ether (butyl carbitol), diethylene glycol dibutyl ether, triethylene glycol monoethyl ether (butyl carbitol), di ... Examples include methyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, methylene dimethyl ether (methylal), propylene glycol monobutyl ether, tetrahydrofuran, acetone, diacetone alcohol, acetonyl acetone, acetyl acetone, ethylene glycol monomethyl ether acetate (methyl cellosolve acetate), diethylene glycol monomethyl ether acetate (methyl carbitol acetate), diethylene glycol monoethyl ether acetate (carbitol acetate), ethyl hydroxyisobutyrate, and ethyl lactate, which can be used alone or in combination of two or more.

[0123] The content of the water-soluble organic solvent in the desorption treatment liquid is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass.

[0124] (non-water-soluble organic solvent) The desorption treatment liquid may contain a water-insoluble organic solvent. Specific examples of water-insoluble organic solvents include alcohol-based solvents such as n-butanol, 2-butanol, isobutanol, and octanol; aliphatic hydrocarbon-based solvents such as hexane, heptane, and normal paraffin; aromatic hydrocarbon-based solvents such as benzene, toluene, xylene, and alkylbenzene; halogenated hydrocarbon-based solvents such as methylene chloride, 1-chlorobutane, 2-chlorobutane, 3-chlorobutane, and carbon tetrachloride; ester-based solvents such as methyl acetate, ethyl acetate, and butyl acetate; ketone-based solvents such as methyl isobutyl ketone, methyl ethyl ketone, and cyclohexanone; and ether-based solvents such as ethyl ether and butyl ether. These can be used alone or in combination of two or more.

[0125] (Antifoaming agent) The release treatment liquid may contain an antifoaming agent. A large amount of bubbles may be generated during stirring or crushing of the substrate during immersion. If bubbles remain, they may overflow during the plastic film recovery process. Furthermore, if a large amount of bubbles are entrained in the release treatment liquid during crushing of the substrate, the substrate may not be crushed to the desired size.

[0126] Compounds commonly used as defoaming agents include water-soluble organic solvents and nonionic surfactants with a low HLB value in the range of 1 to 3, but silicone compounds are particularly preferred because of their high defoaming ability. Among these, emulsion-type and self-emulsifying silicone compounds are preferred.

[0127] The antifoaming agent may be used alone or in combination of two or more kinds. The content of the antifoaming agent in the cleaning liquid usable in step 1 is preferably in the range of 0.01 to 5 wt %, more preferably in the range of 0.02 to 4 wt %, and even more preferably in the range of 0.03 to 3 wt %.

[0128] (liquid temperature) The temperature of the desorption treatment liquid is not particularly limited as long as it can maintain a liquid state, but it is usually preferable to perform the treatment at a liquid temperature of 15 to 90°C. When using a desorption treatment liquid in which a surfactant or the like has been added to water, it is preferable to adjust the liquid temperature depending on the type of surfactant. The optimal temperature for achieving excellent cleaning effects varies depending on the type of surfactant, but is preferably 40°C or higher, preferably 65°C or higher, and more preferably 85°C or higher, for example. It is also preferable to immerse the target printed matter or laminate in, for example, a treatment tank, in a state in which the desorption treatment solution is heated or ultrasonically vibrated to the above temperature. The heating method is not particularly limited, and known heating methods using heat rays, infrared rays, microwaves, etc. can be used. Ultrasonic vibration can be achieved, for example, by attaching an ultrasonic vibrator to the treatment tank and applying ultrasonic vibration to the warm water or alkaline solution.

[0129] (stir) Stirring the printed matter or laminate when immersing it in the release treatment solution is not essential and is optional, but stirring allows for more efficient swelling. It is preferable to keep the stirring speed at a level that does not cause foaming or the like even without adding an antifoaming agent.

[0130] The equipment and method for stirring are not particularly limited, and known methods can be used. Specific examples include an apparatus equipped with a motor with stirring blades that can stir the cleaning solution in a container, an apparatus equipped with a device that generates ultrasonic waves, an apparatus that can shake the entire container, a wet crusher, a water jet stirring method using a water jet pump, and a bubbling method using an inert gas such as nitrogen gas.

[0131] The time for immersing the printed matter or laminate in the desorption treatment solution varies depending on the configuration of the printed matter or laminate, but is generally in the range of 2 minutes to 48 hours. Note that in the printed matter or laminate, it is not necessary for 100% of the coating such as the printed layer to be completely detached from the substrate, but it is preferable that 60% by mass or more of 100% by mass of the coating be detached, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0132] In the detachment step, the film may be immersed in the detachment treatment solution once or several times. That is, the immersion may be performed once, followed by a step of recovering the separated film substrate, or the immersion may be performed several times, followed by a step of recovering the film substrate. When immersion is performed multiple times in the detachment step, the concentration of the detachment treatment solution may be changed. Furthermore, known steps such as washing with water and drying may be added as appropriate during the detachment step.

[0133] The detachment treatment liquid also promotes detachment of the plastic substrate by contacting the printed layer, primer layer, or the interface between the substrate and another layer from the edge of the printed matter or laminate. Therefore, it is preferable that the printed layer, adhesive layer, or primer layer is exposed on the cross section. Therefore, it is more preferable to include a step of fragmenting the printed matter or laminate by cutting or pulverizing.

[0134] The method for crushing the laminate of the present invention is not particularly limited, and can be performed by a known method. Crushing can be performed in an air atmosphere in the absence of liquids such as solvents, or in water or a cleaning solution. When crushing in an air atmosphere, a dry crusher can be used. When crushing in water or a cleaning solution, a wet crusher can be used, which can crush and pump simultaneously.

[0135] After the immersion treatment in the release treatment liquid described above, it is preferable to provide a step of stirring the recovered substrate in water or in the release treatment liquid described above. This step increases the rate at which a coating such as a printed layer is detached from the substrate. The equipment and method for stirring are not particularly limited, and known methods can be used, but stirring is preferably performed using a wet crusher.

[0136] Furthermore, it is preferable to finish washing the recovered substrate by stirring it in a rinse solution to wash away any ink, adhesive, or other substances that have re-adhered to the substrate film and remained in a single layer. Removing even traces of ink remaining on the film surface significantly improves the quality of the recycled pellets. The rinse solution is not particularly limited, and the aforementioned desorption treatment solution can be used as is, but it is preferable that the rinse solution contains an appropriate amount of an organic solvent. The organic solvent preferably contains, for example, one or more water-soluble alcohols or water-soluble solvents having a flash point of 21°C or higher. It is preferable that the rinse solution contains a large amount of a so-called water-soluble solvent containing alcohols. Specifically, the water-soluble solvent is preferably 30% by mass or more, more preferably 40% by mass or more, more preferably 50% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, and more preferably 95% by mass or more. The equipment and method for stirring in the rinse solution are not particularly limited, and known methods can be used. Specific examples include an apparatus equipped with a motor with stirring blades that can stir the cleaning solution in a container, an apparatus equipped with a device that generates ultrasonic waves, an apparatus that can shake the container, a wet crusher, a kneader, etc.

[0137] (Recovery and reuse of desorption treatment liquid) The desorption treatment liquid used in the desorption treatment step can be recycled after being fed to one or more recycling machines selected from a filter, centrifuge, and ultrafilter to recover the solids and then reused. Water, rinse liquid, etc. can also be reused in the same way. While wet crushing is being carried out, the recycling process for water, desorption treatment liquid, rinse liquid, etc. can be continuously operated to separate the solids from the water, washing liquid, and rinse liquid.

[0138] (Drying of plastic separated material) The separated and recovered substrate material is dried (film fragments) to remove residual moisture using one or more methods selected from vacuum heating drying, hot air drying, and pressurized compression drying. As a pretreatment for producing recycled pellets (described below), briquettes may be produced after or during the drying of the recovered film fragments using a pressurized compression machine such as a Nippon Seam compression dehydrator, a Oike Iron Works pellet mill, or an Elcom Stella briquetting machine. When the substrate film is ground into powder using a wet grinder, the crushed material is crushed to approximately 10–500 μm. Due to its high density, the pressurized compression step can be omitted. The density varies depending on the material constituting the crushed material, but a higher density is preferable for ease of handling in a kneader. Specifically, a dry weight of 0.03 kg or more is preferred, with 0.05 kg or more being more preferred, 0.2 kg or more being more preferred, and 0.3 kg or more being even more preferred.

[0139] The pellets of the present invention, which are made primarily from recycled plastic, can be recycled into non-oriented polyolefin films or molded products made by injection molding or the like, thereby maximizing their effectiveness. The method for recycling the unstretched polyolefin film is not particularly limited and can be achieved by known film production methods. For example, melt-kneading methods using common mixers such as single-screw extruders, twin-screw extruders, and multi-screw extruders, or methods in which the components are dissolved or dispersed and mixed and then the solvent is removed by heating, can be used. Considering workability, the use of a single-screw extruder or twin-screw extruder is particularly preferred. When using a single-screw extruder, full-flight screws, screws with mixing elements, barrier-flight screws, fluted screws, and the like can be used without particular limitations. Twin-screw kneading devices include co-rotating twin-screw extruders and counter-rotating twin-screw extruders, and the screw shapes are not particularly limited, including full-flight screws and kneading disk types. Alternatively, a method in which the material is melted in a single-screw extruder or twin-screw extruder, etc., and then passed through a feed block or multi-manifold and then subjected to film formation using a T-die can also be used. Furthermore, if necessary, the recycled film can be subjected to a surface modification treatment to appropriately improve its suitability for subsequent processes. For example, to improve printability when used as a standalone film or lamination suitability when used in a laminated structure, a surface modification treatment can be performed on the surface that comes into contact with other substrates. Suitable surface modification treatments include corona discharge treatment, plasma treatment, flame treatment, and other methods that oxidize the film surface to develop functional groups, as well as wet process methods such as coating with an easy-adhesion layer.

[0140] In addition, in the same manner as with pellets made primarily from virgin plastics, the plastic may be molded into a molded article by a conventional molding method other than the above-mentioned film formation, such as injection molding, extrusion molding, vacuum molding, pressure molding, blow molding, or the like, and used for various purposes. For example, it can be used as daily necessities, stationery, toys, sporting goods, home appliances, and automobile parts used in ordinary households, as well as films, sheets, and fibers. If there are no hygiene issues, it can also be used in medical devices, food containers, and food packaging materials. [Example]

[0141] The present invention will be described in more detail below with reference to specific examples, but the present invention is not limited to these examples. In the following examples, "parts" and "%" represent "parts by mass" and "% by mass", respectively, unless otherwise specified.

[0142] <Preparation of each detachment coating-forming composition> Each component was mixed according to the formulation shown in Tables 1 to 3 to prepare each of the detachment coating-forming compositions of the Examples and Comparative Examples. The numbers in the table represent the solid content excluding the solvent, and blank spaces indicate that the material is not blended. The abbreviations are as follows:

[0143] Varnish A: An acid-modified polyolefin resin solution containing 10 mass % of acid-modified polyolefin resin, 18 mass % of ethyl acetate, and 72 mass % of methylcyclohexane. Varnish B: A rosin resin solution containing 50% by mass of rosin-modified fumaric acid resin and 50% by mass of isopropyl alcohol (hereinafter referred to as IPA). Varnish C: A polyamide resin solution containing 38 mass% solid polyamide resin, 38 mass% methylcyclohexane, 11 mass% methanol, 11 mass% ethanol, 1.8 mass% IPA, and 0.2 mass% N-octadecyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate. Varnish D: A chelating varnish containing 45 mass % acetonate, 33.3 mass % IPA, 21.4 mass % ethanol, and 0.3 mass % methanol. Varnish E: A polyurethane resin solution containing 30% by mass of polyurethane resin, 49% by mass of ethyl acetate, and 21% by mass of IPA. Wax F: Polyethylene wax containing 50% by mass of polyethylene wax and 50% by mass of starch. Matting agent: silicon dioxide

[0144] [Creation of printed materials] Each release coating composition was applied to a biaxially oriented polypropylene film (15 μm thick) that had not been corona discharge treated using bar coater #5 and left for 24 hours to form a coating. Then, the inks "UNITAF 507 Primary Blue A-21" and "XOP-1385 HC White S," both containing chlorinated polyolefin resin, were applied to the coating using bar coater #4 and left for 24 hours to form a print.

[0145] [Deinking property] The printed matter was immersed in a 1.5% aqueous solution of sodium hydroxide at 85°C for 15 minutes. After that, the printed matter was removed, and the printed surface was rubbed with a finger or cork, and the state of ink absorption was visually evaluated. The evaluation was as follows: 〇 The ink on the printed surface can be rubbed lightly with a finger. △ The ink on the printed surface does not come off when lightly rubbed with a finger, but comes off when rubbed hard with a cork. × The ink on the printed surface does not come off even with a finger or cork.

[0146] [Adhesion] After cellophane tape (manufactured by Nichiban Co., Ltd.) was applied to the printed surface of the above-mentioned printed matter, the tape was quickly peeled off, and the state of the printed surface was visually evaluated. The evaluation was as follows. 〇 Most of the printed surface remains uncovered by the cellophane tape. △ The printed surface is slightly covered by the cellophane tape. × Most of the printed surface is covered by the cellophane tape.

[0147] [Fir-resistant] The printed surfaces of the above printed materials were placed together, rubbed back and forth five times, and the state of ink absorption was visually evaluated. The evaluation was as follows: 〇 The ink hardly comes off. Ink peels off slightly. × Most of the ink comes off.

[0148] 〔scratch〕 The printed surface of the above-mentioned print was rubbed with a fingernail 20 times, and the state of ink absorption was visually evaluated. The evaluation was as follows: 〇 Almost no ink is scraped off. Some ink is scraped off. × The ink is completely scraped off.

[0149] [Heat-resistant blocking] The printed surface of the above printed matter was placed on expanded polystyrene, and the resulting material was pressed together with a heat seal bar at 120°C under a pressure of 0.1 MPa for 1 second, and the ink removal was checked. The results were evaluated as follows: ○ No transfer or dot-like ink transfer can be seen △ Dot-like ink transfer occurs in a line × Dot-like ink transfer on the surface

[0150] The results are shown in Tables 1 to 3.

[0151] [Table 1]

[0152] [Table 2]

[0153] [Table 3]

[0154] <Preparation of each detachment coating-forming composition> The components were mixed according to the formulation shown in Table 4 to prepare the respective detachment coating-forming compositions of the Examples and Comparative Examples. The numbers in the table represent the solid content excluding the solvent, and blank spaces indicate that the material is not blended. The abbreviations are as follows:

[0155] Varnish G: An acid-modified polyolefin resin solution containing 20 mass % of acid-modified polyolefin resin, 16 mass % of ethyl acetate, and 64 mass % of methylcyclohexane.

[0156] [Creation of printed materials] (Printed matter of Example 13) The detachment coating composition of Example 13 was applied to a biaxially oriented polypropylene film (thickness: 15 μm) that had not been subjected to corona discharge treatment using bar coater #5 and left for 24 hours to produce a coating. Then, chlorinated polyolefin resin-containing inks "UNITAF 105 Red A-11" and "XOP-1385 HC White S" were applied to the coating using bar coater #4 and left for 24 hours to produce a printed matter.

[0157] (Printed matter of Examples 14 and 15) Each of the detachment coating compositions of Examples 14 and 15 was applied to a biaxially oriented polypropylene film (thickness: 15 μm) that had not been subjected to corona discharge treatment using bar coater #5 and left for 24 hours to produce a coating. Then, a urethane resin-based red ink containing no chlorinated polyolefin resin and a urethane resin-based white ink containing no chlorinated polyolefin resin were applied to the coating using bar coater #4 and left for 24 hours to produce a printed matter.

[0158] (Printed matter of Example 16) Each of the detachment coating compositions of Example 16 was applied to a biaxially oriented polypropylene film (15 μm thick) that had not been subjected to corona discharge treatment using bar coater #5, and left for 24 hours to produce a coating. Then, an acrylic ink containing no chlorinated polyolefin resin, "STC SW 105 Red No. 2," and a urethane resin-based white ink containing no chlorinated polyolefin resin were applied to the coating using bar coater #4, and the resulting ink was left for 24 hours to produce a printed product.

[0159] (Printed matter of Comparative Example 13) Chlorinated polyolefin resin-containing inks "UNITAF 105 Red A-11" and "XOP-1385 HC White S" were applied to biaxially oriented polypropylene film (thickness 15 μm) that had not been subjected to corona discharge treatment using bar coater #4, and the film was left to stand for 24 hours to produce a printed matter. Comparative Example 13 was configured such that the ink was applied directly to the film without using a detachable film-forming composition.

[0160] (Printed matter of Comparative Example 14) A urethane-based red ink containing no chlorinated polyolefin resin and a urethane-based white ink containing no chlorinated polyolefin resin were applied to a biaxially oriented polypropylene film (thickness 15 μm) that had not been subjected to corona discharge treatment using bar coater #4, and the resulting ink was left for 24 hours to produce a printed material. Comparative Example 14 was configured such that the ink was applied directly to the film without using a detachable film-forming composition.

[0161] (Printed matter of Comparative Example 15) A biaxially oriented polypropylene film (thickness 15 μm) that had not been subjected to corona discharge treatment was coated with an acrylic ink containing no chlorinated polyolefin resin, "STC SW 105 Red No. 2," and a urethane-based white ink containing no chlorinated polyolefin resin, using bar coater #4, and left to stand for 24 hours to produce a printed matter. Comparative Example 15 was constructed in such a way that the ink was applied directly to the film without using a detachable film-forming composition.

[0162] [Table 4]

Claims

1. A detachable coating-forming composition that can be detached from a substrate by treatment with an alkaline solution, comprising: A detachment film-forming composition comprising a non-chlorinated polyolefin resin containing no chlorine atoms, a rosin-based resin, and at least one selected from a polyamide-based resin and a urethane resin.

2. 2. The film-forming composition for detachment according to claim 1, wherein the non-chlorinated polyolefin resin is an acid-modified polyolefin having a melting point of 50°C or higher and 100°C or lower.

3. 3. The detachment coating-forming composition according to claim 1, wherein the non-chlorinated polyolefin resin is contained in an amount of 1.0 to 50.0% by mass based on the total amount of solids in the composition.

4. 3. The detachment coating-forming composition according to claim 1, wherein the rosin-based resin is contained in an amount of 1.0 to 70.0% by mass based on the total amount of solids in the composition.

5. 3. The detachment coating-forming composition according to claim 1, wherein the urethane resin and / or polyamide resin is contained in an amount of 5.0 to 50.0 mass % based on the total amount of solids in the composition.

6. The detachable coating-forming composition according to claim 1 or 2, further comprising a wax.

7. 3. The detachment coating-forming composition according to claim 1, further comprising an organic solvent, the organic solvent being at least one selected from the group consisting of aromatic solvents, ketone solvents, ester solvents, and alcohol solvents.

8. A laminate having a primer layer formed on a substrate from the release coating-forming composition of claim 1.

9. A laminate comprising a substrate, a primer layer formed from the detachable coating-forming composition according to claim 1, and a printed layer, in this order.

10. The laminate according to claim 9 , wherein the primer layer and the printed layer do not contain a chlorine-based resin.

11. A packaging material or an integrated packaging film using the laminate according to claim 8 or 9.

12. A recycled plastic made from a packaging material or an integrated packaging film using the laminate according to claim 8 or 9.

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