Adhesive treatment liquid, method for producing reused base using adhesive treatment liquid, and method for producing reused polymer composition using adhesive treatment liquid

Abstract

Provided is an adhesive treatment liquid which can easily remove an adhesive and has little environmental burden. Also provided is a method for producing a recycled substrate using the adhesive treatment liquid, the method being capable of easily recovering a recycled substrate in which contamination and corrosion are suppressed from an adhesive tape comprising a substrate and an adhesive using the adhesive treatment liquid. Also provided is a method for producing a recycled polymer composition that can be used as a raw material for a recycled adhesive using the adhesive treatment liquid. A binder treatment liquid according to an embodiment of the present invention is a binder treatment liquid for treating a binder, the binder treatment liquid containing water, an organic solvent, and a basic compound, the organic solvent and the water being in a phase-separated state.

Description

Technical Field

[0001] The present invention relates to a binder treatment liquid, a method for producing a recycled base material using the binder treatment liquid, and a method for producing a recycled polymer composition using the binder treatment liquid. Background Art

[0002] Adhesive tapes are widely used for attaching labels to articles and packaging materials, packing packaging materials, using in the manufacturing process of electronic components and optical components, masking purposes, etc. In particular, the use of adhesive tapes in the manufacturing process of electronic components and optical components has been increasing in recent years, and a large amount of adhesive tape waste is generated at manufacturing sites.

[0003] The waste of adhesive tapes is usually disposed of by incineration or placed in a waste disposal site, but such disposal is not preferred from the perspective of reducing environmental load and further from the perspective of resource recycling.

[0004] Therefore, it is necessary to reduce the waste disposal of adhesive tapes as much as possible, and to recycle resources. As a means of reducing the waste disposal of such adhesive tapes, the recycling of adhesive tape raw materials is considered. If the recycling technology of adhesive tape raw materials is established, it will help to suppress the amount of CO2 emissions consumed by fossil resource mining, and it is expected to have a great effect on solving the problem of climate change.

[0005] As raw materials of the adhesive tape, adhesives and substrates can be representatively cited. The adhesive tape is typically obtained as follows: a polymer (sometimes referred to as a base polymer) and additives such as a crosslinking agent that meet the purpose are dissolved in a solvent to form an adhesive composition, which is applied to a substrate, and heated and dried as needed to allow a crosslinking reaction to proceed, thereby forming an adhesive on the substrate, thereby obtaining (for example, Patent Document 1).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2021-175796 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] The present invention aims to provide an adhesive treatment liquid that can easily remove an adhesive and has a low environmental load. Another object of the present invention is to provide a method for producing a recycled substrate using the adhesive treatment liquid, which can easily recover a recycled substrate with suppressed contamination / corrosion from an adhesive tape containing a substrate and an adhesive using the adhesive treatment liquid. Furthermore, another object of the present invention is to provide a method for producing a recycled polymer composition that can be a raw material for a recycled adhesive using the adhesive treatment liquid.

[0011] Solutions for solving problems

[0012] [1] The binder treatment liquid according to an embodiment of the present invention is a binder treatment liquid for treating a binder, and the binder treatment liquid contains water, an organic solvent, and a basic compound, wherein the organic solvent and the water are in a phase-separated state.

[0013] [2] In the binder treatment liquid described in [1] above, the concentration of the alkaline compound in the binder treatment liquid may be 0.001 wt % to 50 wt %.

[0014] [3] In the binder treatment liquid described in [1] or [2] above, a relative distance Ra between the Hansen solubility parameter value of the water and the Hansen solubility parameter value of the organic solvent may be 24 or more.

[0015] Here, the relative distance Ra is calculated using the following formula.

[0016] Ra=√[4(δD2-δD1) 2 +(δP2-δP1) 2 +(δH2-δH1) 2 ]

[0017] δD1: Energy of dispersion force between molecules based on organic solvent (unit: MPa) 0.5 )

[0018] δD2: Energy based on the dispersion force between water molecules (unit: MPa) 0.5 )

[0019] δP1: Energy of dipole interaction between molecules based on organic solvent (unit: MPa) 0.5 )

[0020] δP2: Energy based on dipole interactions between water molecules (in MPa) 0.5 )

[0021] δH1: Energy of hydrogen bonds between molecules based on organic solvents (in MPa) 0.5 )

[0022] δH2: Energy of hydrogen bonds between water molecules (in MPa) 0.5 )

[0023] [4] In the binder treatment liquid according to any one of [1] to [3] above, the organic solvent may be a single solvent.

[0024] [5] In the binder treatment liquid according to any one of [1] to [3] above, the organic solvent may be a mixed solvent.

[0025] [6] In the binder treatment liquid described in any one of [1] to [5] above, the content ratio of the organic solvent when the total of the water and the organic solvent in the binder treatment liquid is 100 volume % may be 1 volume % to 85 volume %.

[0026] [7] In the adhesive treatment liquid according to any one of [1] to [6] above, the adhesive may be an adhesive contained in an adhesive tape.

[0027] [8] A method for manufacturing a recyclable substrate according to an embodiment of the present invention is a method for manufacturing a recyclable substrate from an adhesive tape comprising a substrate and an adhesive, the manufacturing method comprising the following impregnation step: impregnating the adhesive treatment liquid described in any one of [1] to [7] above into the adhesive to perform an impregnation treatment.

[0028] [9] In the method for producing a recycled base material described in [8] above, in the impregnation step, the binder treatment liquid may be subjected to at least one selected from the group consisting of stirring and ultrasonic irradiation.

[0029]

[10] The method for producing a recycled substrate described in [8] or [9] above may include, after the impregnation step, a raw material separation step of separating the structure derived from the substrate from the adhesive tape.

[0030]

[11] In the method for producing a recycled base material described in

[10] above, in the raw material separation step, a cleaning liquid may be added to the pressure-sensitive adhesive tape after the impregnation treatment.

[0031]

[12] The method for producing a recycled substrate described in

[11] above may include a liquid separation step of separating water and the organic solvent.

[0032]

[13] A method for producing a recycled polymer composition according to an embodiment of the present invention is a method for producing a recycled polymer composition from an adhesive tape comprising a substrate and an adhesive, the method comprising an impregnation step of impregnating the adhesive with the adhesive treatment liquid described in any one of [1] to [7] above.

[0033]

[14] In the method for producing a recycled polymer composition according to

[13] above, in the impregnation step, the binder treatment liquid may be subjected to at least one selected from the group consisting of stirring and ultrasonic irradiation.

[0034]

[15] In the method for producing a recycled polymer composition according to

[14] , the binder treatment liquid may be heated in the impregnation step.

[0035]

[16] In the method for producing a recycled polymer composition according to any one of

[13] to

[15] above, after the impregnation step, a raw material separation step of separating the composition derived from the adhesive from the adhesive tape may be included.

[0036]

[17] In the method for producing a recycled polymer composition according to

[16] above, in the raw material separation step, washing water may be added to the adhesive tape after the impregnation treatment.

[0037]

[18] The method for producing a recycled polymer composition described in

[17] above may include a liquid separation step of separating water and the organic solvent.

[0038] Effects of the Invention

[0039] According to the present invention, it is possible to provide an adhesive treatment liquid that can easily remove an adhesive and has a low environmental load. In addition, it is possible to provide a method for producing a recycled substrate using the adhesive treatment liquid, which can easily recover a recycled substrate with suppressed contamination / corrosion from an adhesive tape containing a substrate and an adhesive using the adhesive treatment liquid. Furthermore, it is possible to provide a method for producing a recycled polymer composition that can be a raw material for a recycled adhesive using the adhesive treatment liquid. DETAILED DESCRIPTION

[0040] When "weight" is expressed in this specification, it can also be replaced with "mass" which is a commonly used SI unit expressing weight.

[0041] In this specification, the term "(meth)acrylic acid" means "acrylic acid and / or methacrylic acid", the term "(meth)acrylate" means "acrylate and / or methacrylate", the term "(meth)allyl" means "allyl and / or methallyl", and the term "(meth)acrolein" means "acrolein and / or methacrolein".

[0042] <<1. Adhesive treatment liquid>>

[0043] The binder treatment liquid according to the embodiment of the present invention is a binder treatment liquid for treating a binder, and the binder treatment liquid includes water, an organic solvent, and an alkaline compound.

[0044] The adhesive treated with the adhesive treatment liquid of the embodiment of the present invention can be any adhesive in an appropriate form within the scope that does not damage the effect of the present invention. As such an adhesive, in terms of further demonstrating the effect of the present invention, it is preferably an adhesive contained in an adhesive tape, and more preferably an adhesive contained in an adhesive tape comprising a substrate and an adhesive.

[0045] The binder treatment liquid according to the embodiment of the present invention only needs to contain water, an organic solvent, and a basic compound, and may contain any other appropriate components within a range that does not impair the effects of the present invention.

[0046] The total content ratio of water, organic solvent and alkaline compound in the adhesive treatment liquid of the embodiment of the present invention is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, further preferably 90% by weight to 100% by weight, particularly preferably 95% by weight to 100% by weight, and most preferably 98% by weight to 100% by weight in order to further demonstrate the effect of the present invention.

[0047] In order to further demonstrate the effect of the present invention, the water content ratio in the adhesive treatment liquid of the embodiment of the present invention when the total of water and the organic solvent is set to 100 volume % is preferably 15 volume % to 99 volume %, more preferably 25 volume % to 99 volume %, further preferably 55 volume % to 99 volume %, particularly preferably 65 volume % to 99 volume %, and most preferably 85 volume % to 99 volume %.

[0048] In order to further demonstrate the effect of the present invention, the content ratio of the organic solvent in the adhesive treatment liquid of the embodiment of the present invention when the total of water and the organic solvent is set to 100 volume %, is preferably 1 volume % to 85 volume %, more preferably 1 volume % to 75 volume %, further preferably 1 volume % to 45 volume %, particularly preferably 1 volume % to 35 volume %, and most preferably 1 volume % to 15 volume %.

[0049] The concentration of the alkaline compound in the adhesive treatment liquid of the embodiment of the present invention is preferably 0.001 wt % to 50 wt %, more preferably 1 wt % to 30 wt %, further preferably 1 wt % to 15 wt %, particularly preferably 1 wt % to 10 wt %, and most preferably 1 wt % to 5 wt % in order to further demonstrate the effect of the present invention. If the concentration of the alkaline compound in the adhesive treatment liquid is within the above range, the effect of the present invention can be further demonstrated. If the concentration of the alkaline compound in the adhesive treatment liquid is too high, there is a concern that the alkaline compound becomes difficult to dissolve.

[0050] The organic solvent may be a single solvent or a mixed solvent. In the case of a mixed solvent, it may be a mixed solvent of two or more types.

[0051] As the organic solvent, any appropriate organic solvent can be used within the range that does not impair the effect of the present invention. Examples of such organic solvents include alcohols, hydrocarbons, ketones, esters, ethers, amines, nitriles, carboxylic acids, terpenes, nitro compounds, and halogen compounds.

[0052] Examples of alcohols include methanol (HSP value = 29.6), ethanol (HSP value = 26.5), 1-propanol (HSP value = 24.6), 2-propanol (IPA) (HSP value = 23.6), 1-butanol (HSP value = 23.2), 1-pentanol (HSP value = 21.7), 1-hexanol (HSP value = 21.2), benzyl alcohol (HSP value = 23.8), diethylene glycol (HSP value = 27.9), and dipropylene glycol (HSP value = 26.4).

[0053] Examples of hydrocarbons include benzene (HSP value = 18.5), toluene (HSP value = 18.2), styrene (HSP value = 19.1), hexane (HSP value = 14.9), cyclohexane (HSP value = 16.8), heptane (HSP value = 15.3), and methylcyclohexane (HSP value = 16.0).

[0054] Examples of ketones include acetone (HSP value = 19.9) and methyl ethyl ketone (HSP value = 19.1).

[0055] As esters, for example, ethyl acetate (HSP value = 18.2) can be mentioned.

[0056] Examples of the ethers include tetrahydrofuran (HSP value = 19.5) and cyclopentyl methyl ether (HSP value = 17.8).

[0057] Examples of the amines include aniline (HSP value = 23.7).

[0058] Examples of nitriles include acetonitrile (HSP value = 24.4).

[0059] Examples of carboxylic acids include acetic acid (HSP value = 21.4).

[0060] Examples of terpenes include d-limonene (HSP value = 17.8).

[0061] Examples of nitro compounds include nitrobenzene (HSP value = 22.8).

[0062] Examples of the halogen compounds include chloroform (HSP value = 18.9) and carbon tetrachloride (HSP value = 17.8).

[0063] It should be noted that the above HSP value is the "Hansen solubility parameter value", which is the Hildebrand solubility parameter value divided into dispersion terms (δ D ), polar term (δ p ), and hydrogen bonding terms (δ H ) and the parameter values ​​of the polarity of the substance are taken into account. The dispersion term (the term related to van der Waals force), the polar term (the term related to dipole moment), and the hydrogen bond term (the term related to hydrogen bonding) can be expressed in three-dimensional coordinates.

[0064] The Hansen solubility parameter value of a mixture of two or more liquids can be calculated by the following formula (1) as the weighted average value m of the HSP values ​​of each solvent. It should be noted that δ1 and δ2 are the HSP values ​​of each liquid component, and is the volume fraction of each liquid component.

[0065]

[0066] The Hansen solubility parameter value of a mixture of two or more liquids is shown in the following formula (2), and can also be calculated from the volume fractions of the dispersion term, polar term, and hydrogen bonding term of each solvent. D1 and δ D2 is the dispersion term of each liquid component, δ P1 and δ P2 is the polarity term of each liquid component, δ H1 and δ H2 is the hydrogen bonding term of each liquid component, and is the volume fraction of each liquid component.

[0067]

[0068] The Hansen solubility parameter values ​​of each solvent are included in "HSPiP Version 5", and for solvents not included in the list, values ​​estimated by "HSPiP Version 5" were used.

[0069] As the basic compound, any appropriate basic compound can be adopted within the scope of not impairing the effect of the present invention. As such a basic compound, for example, hydroxides, carbonates, etc. of alkali metals or alkaline earth metals such as potassium hydroxide, sodium hydroxide, and calcium hydroxide, and metal alkoxides such as sodium methoxide, sodium ethoxide, and potassium tert-butoxide can be cited, preferably at least one selected from the group consisting of potassium hydroxide, sodium hydroxide, and sodium ethoxide.

[0070] In the binder treatment liquid of the embodiment of the present invention, the organic solvent and water form a phase-separated state. Here, "the organic solvent and water form a phase-separated state" means that the liquid is suspended in a state where the liquid to be the object is shaken and stirred 10 times or more, or the liquid is separated into two or more phases in a state where the liquid to be the object is shaken and stirred 10 times or more and then left to stand for 3 minutes or more, and means that the organic solvent and water are not uniformly miscible.

[0071] The present invention is based on the following technical concept: for an adhesive treatment liquid containing water, an organic solvent and an alkaline compound, the type and amount of the organic solvent and the amount of water are selected in such a way that the organic solvent and water contained in the adhesive treatment liquid form a phase-separated state, thereby forming an adhesive treatment liquid with a small environmental load that can easily remove the adhesive.

[0072] In the binder treatment liquid of the embodiment of the present invention, the relative distance Ra between the Hansen solubility parameter value of water contained in the binder treatment liquid and the Hansen solubility parameter value of the organic solvent contained in the binder treatment liquid is preferably greater than 24. If the relative distance Ra is greater than 24, the organic solvent and water contained in the binder treatment liquid tend to form a phase separation state, thereby further demonstrating the effect of the present invention.

[0073] Here, the relative distance Ra is calculated by the following formula.

[0074] Ra=√[4(δD2-δD1) 2 +(δP2-δP1) 2 +(δH2-δH1) 2 ]

[0075] δD1: Energy of dispersion force between molecules based on organic solvent (unit: MPa) 0.5 )

[0076] δD2: Energy based on the dispersion force between water molecules (unit: MPa) 0.5 )

[0077] δP1: Energy of dipole interaction between molecules based on organic solvent (unit: MPa) 0.5 )

[0078] δP2: Energy based on dipole interactions between water molecules (in MPa) 0.5 )

[0079] δH1: Energy of hydrogen bonds between molecules based on organic solvents (in MPa) 0.5 )

[0080] δH2: Energy of hydrogen bonds between water molecules (in MPa) 0.5 )

[0081] In terms of further expressing the effect of the present invention, the relative distance Ra is more preferably 25 or more, further preferably 26 or more, further preferably 27 or more, further preferably 28 or more, particularly preferably 29 or more, and most preferably 30 or more.

[0082] The upper limit of the relative distance Ra is preferably 42 or less, more preferably 40 or less, further preferably 38 or less, particularly preferably 36 or less, and most preferably 35 or less. If the relative distance Ra is too large, for example, when an adhesive tape including a substrate and an adhesive is treated as a treatment object, there is a concern that the substrate may be contaminated or corroded.

[0083] 《2. Method for producing a recycled substrate》

[0084] The method for producing a recycled substrate according to an embodiment of the present invention is a method for producing a recycled substrate from an adhesive tape including a substrate and an adhesive, and the method includes an impregnation step of impregnating the adhesive tape with the adhesive treatment solution according to an embodiment of the present invention.

[0085] <2-1. Adhesive tape>

[0086] The adhesive tape comprises a substrate and an adhesive.

[0087] In consideration of functioning as a pressure-sensitive adhesive tape, the thickness of the substrate is preferably 1 μm to 500 μm, more preferably 5 μm to 300 μm, further preferably 10 μm to 100 μm, particularly preferably 15 μm to 80 μm, and most preferably 20 μm to 60 μm.

[0088] As the material of the substrate, any appropriate material can be adopted within the range that does not impair the effects of the present invention. Representative examples of the material of such a substrate include resin materials and metal materials such as SUS.

[0089] For the resin material used as the substrate, for example, there can be mentioned acrylic resins such as polyimide (PI), polyetheretherketone (PEEK), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polymethyl methacrylate (PMMA), polycarbonate, triacetyl cellulose (TAC), polysulfone, polyarylate, polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), wholly aromatic polyamide (aramid), polyvinyl chloride (PVC), polyvinyl acetate, polyphenylene sulfide (PPS), fluorine-based resins, and cyclic olefin polymers.

[0090] The adhesive forms an adhesive layer on the substrate.

[0091] In view of the function as a pressure-sensitive adhesive tape, the thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 250 μm, more preferably 2 μm to 150 μm, further preferably 3 μm to 100 μm, and particularly preferably 5 μm to 50 μm.

[0092] The adhesive tape can be manufactured by any appropriate method within the scope of not impairing the effect of the present invention. As such a manufacturing method, for example, the following method can be cited:

[0093] (1) A method for forming an adhesive on a substrate;

[0094] (2) A method of transferring an adhesive formed on a release liner to a substrate;

[0095] (3) A method of laminating an adhesive onto a substrate.

[0096] The adhesive tape may also be provided with any appropriate release liner on the surface of the adhesive on the opposite side to the substrate for protection until use. Examples of release liners include: release liners whose surfaces of substrates (liner substrates) such as paper and plastic films are treated with silicone; release liners whose surfaces of substrates (liner substrates) such as paper and plastic films are laminated with polyolefin resins; etc. Examples of plastic films as liner substrates include polyethylene films, polypropylene films, polybutylene films, polybutadiene films, polymethylpentene films, polyvinyl chloride films, vinyl chloride copolymer films, polyethylene terephthalate films, polybutylene terephthalate films, polyurethane films, ethylene-vinyl acetate copolymer films, etc. The thickness of the release liner is preferably 1 μm to 500 μm, more preferably 3 μm to 450 μm, further preferably 5 μm to 400 μm, and particularly preferably 10 μm to 300 μm.

[0097] One embodiment of the adhesive is an acrylic adhesive. As the acrylic adhesive, any appropriate acrylic adhesive can be used within the range that does not impair the effect of the present invention. As such an acrylic adhesive, a representative example of a waste acrylic adhesive (sometimes referred to as "waste acrylic adhesive") can be cited. As waste acrylic adhesives, for example, acrylic adhesives contained in acrylic adhesive tapes recovered after use, acrylic adhesives remaining as residual adhesive on an adherend when an acrylic adhesive tape is peeled off from an adherend to which the acrylic adhesive tape is adhered, and acrylic adhesives attached to an acrylic adhesive manufacturing device can be cited.

[0098] Acrylic adhesive can be formed by any appropriate method. As such a method, for example, a method formed by an acrylic adhesive composition can be cited, and more specifically, the following method can be cited: the acrylic adhesive composition is coated on any appropriate substrate, heated and dried as required, and solidified as required to form an adhesive (specifically, an adhesive layer) on the substrate. As such a coating method, for example, methods such as a gravure roll coater, a reverse roll coater, a lick coater, a dip roll coater, a rod coater, a blade coater, an air knife coater, a spray coater, a comma coater, a direct coater, a roller brush coater, and a die coater can be cited.

[0099] In order to further exhibit the effects of the present invention, the acrylic pressure-sensitive adhesive composition preferably contains an acrylic polymer and a cross-linking agent.

[0100] The acrylic polymer can be referred to as a so-called base polymer in the field of acrylic pressure-sensitive adhesives. The acrylic polymer may be one type or two or more types.

[0101] The content of the acrylic polymer in the acrylic pressure-sensitive adhesive composition is preferably 50 to 100 wt %, more preferably 60 to 100 wt %, further preferably 70 to 100 wt %, particularly preferably 80 to 100 wt %, and most preferably 90 to 100 wt %, in terms of solid content.

[0102] As the acrylic polymer, any appropriate acrylic polymer can be adopted within a range not impairing the effects of the present invention.

[0103] The weight average molecular weight of the acrylic polymer is preferably 100,000 to 3,000,000, more preferably 150,000 to 2,000,000, further preferably 200,000 to 1,500,000, particularly preferably 250,000 to 1,000,000.

[0104] The Tg (glass transition temperature) of the acrylic polymer is preferably -100°C to 30°C, more preferably -95°C to 20°C, further preferably -90°C to 10°C, particularly preferably -80°C to 0°C.

[0105] In order to further demonstrate the effects of the present invention, the acrylic polymer is preferably an acrylic polymer formed by polymerization of a composition (A) comprising: (a) an alkyl (meth)acrylate having an alkyl group with 4 to 12 carbon atoms in the alkyl ester moiety; and (b) at least one selected from the group consisting of (meth)acrylates having an OH group and (meth)acrylic acid. (a) and (b) may each independently be one or more.

[0106] Examples of the alkyl (meth)acrylate (component a) in which the alkyl group of the alkyl ester moiety has 4 to 12 carbon atoms include n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, and dodecyl (meth)acrylate. Among these, n-butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate are preferred, and n-butyl acrylate and 2-ethylhexyl acrylate are more preferred in terms of further exhibiting the effects of the present invention.

[0107] As at least one (component b) selected from the group consisting of (meth)acrylates and (meth)acrylic acid having an OH group, for example, (meth)acrylates having an OH group such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate, (meth)acrylic acid, etc. can be mentioned. Among these, hydroxyethyl (meth)acrylate and (meth)acrylic acid are preferred, and hydroxyethyl acrylate and acrylic acid are more preferred in terms of further expressing the effects of the present invention.

[0108] The composition (A) may contain a copolymerizable monomer other than the components (a) and (b). The copolymerizable monomer may be one kind or two or more kinds. Examples of such copolymerizable monomers include carboxyl group-containing monomers (excluding (meth)acrylic acid) such as itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and their anhydrides (e.g., anhydride group-containing monomers such as maleic anhydride and itaconic anhydride); amide group-containing monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, and N-hydroxyethyl(meth)acrylamide; amino group-containing monomers such as aminoethyl(meth)acrylate, dimethylaminoethyl(meth)acrylate, and tert-butylaminoethyl(meth)acrylate; epoxy group-containing monomers such as glycidyl(meth)acrylate and methylglycidyl(meth)acrylate; cyano group-containing monomers such as acrylonitrile and methacrylonitrile; N-vinyl-2-pyrrolidone, (meth)acryloylmorpholine, N-vinylpiperidone, N-vinyl Heterocyclic vinyl monomers such as 1-aminopiperazine, N-vinylpyrrole, N-vinylimidazole, vinylpyridine, vinylpyrimidine, and vinyloxazole; sulfonic acid group-containing monomers such as sodium vinyl sulfonate; phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; imide group-containing monomers such as cyclohexylmaleimide and isopropylmaleimide; isocyanate group-containing monomers such as 2-methacryloyloxyethyl isocyanate; (meth)acrylates having alicyclic hydrocarbon groups such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate; (meth)acrylates having aromatic hydrocarbon groups such as phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, and benzyl (meth)acrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyltoluene; olefins and dienes such as ethylene, butadiene, isoprene, and isobutylene; vinyl ethers such as vinyl alkyl ether; vinyl chloride; etc.

[0109] As copolymerizable monomers, multifunctional monomers may also be used. Multifunctional monomers refer to monomers having two or more ethylenically unsaturated groups in one molecule. As ethylenically unsaturated groups, any appropriate ethylenically unsaturated groups may be used within the scope of not impairing the effects of the present invention. As such ethylenically unsaturated groups, for example, free radical polymerizable functional groups such as vinyl, propenyl, isopropenyl, vinyl ether (vinyloxy), allyl ether (allyloxy) may be cited. Examples of the multifunctional monomer include hexanediol di(meth)acrylate, butanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, and urethane acrylate. Such a multifunctional monomer may be used alone or in combination of two or more.

[0110] As the copolymerizable monomer, an alkoxyalkyl (meth)acrylate may also be used. Examples of the alkoxyalkyl (meth)acrylate include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, and 4-ethoxybutyl (meth)acrylate. The alkoxyalkyl (meth)acrylate may be one or more.

[0111] The content of the (meth)acrylic acid alkyl ester (component a) in which the alkyl group of the alkyl ester moiety has 4 to 12 carbon atoms is preferably 50% by weight or more, more preferably 60% to 100% by weight, further preferably 70% to 100% by weight, and particularly preferably 80% to 100% by weight, based on the total amount of monomer components constituting the acrylic polymer (100% by weight), in order to further exhibit the effects of the present invention.

[0112] The content of at least one (component b) selected from the group consisting of (meth)acrylates having an OH group and (meth)acrylic acid is preferably 0.1% by weight or more, more preferably 1.0% by weight to 50% by weight, further preferably 1.5% by weight to 40% by weight, and particularly preferably 2.0% by weight to 30% by weight, based on the total amount (100% by weight) of the monomer components constituting the acrylic polymer, in order to further exhibit the effects of the present invention.

[0113] In the acrylic polymer, the total amount of the above-mentioned (a component), the above-mentioned (b component) and the carboxyl group-containing monomer is preferably 5% to 95% by weight, more preferably 10% to 95% by weight, further preferably 15% to 95% by weight, further preferably 20% to 95% by weight, further preferably 25% to 95% by weight, further preferably 30% to 95% by weight, particularly preferably 35% to 90% by weight, and most preferably 40% to 90% by weight, relative to the total amount of monomer components (100% by weight).

[0114] Composition (A) can contain any appropriate other components within the scope of not damaging the effect of the present invention. As such other components, for example, polymerization initiator, chain transfer agent, solvent etc. can be cited. The content of these other components can adopt any appropriate content within the scope of not damaging the effect of the present invention.

[0115] The polymerization initiator may be a thermal polymerization initiator, a photopolymerization initiator (photoinitiator), etc., depending on the type of polymerization reaction. The polymerization initiator may be used alone or in combination of two or more.

[0116] The thermal polymerization initiator can be preferably used when the acrylic polymer is obtained by solution polymerization. As such a thermal polymerization initiator, for example, an azo polymerization initiator, a peroxide polymerization initiator (for example, dibenzoyl peroxide, tert-butyl permaleate, etc.), a redox polymerization initiator, etc. can be cited. Among these thermal polymerization initiators, the azo initiator disclosed in Japanese Patent Publication No. 2002-69411 is particularly preferred. This azo polymerization initiator is preferred because the decomposition product of the polymerization initiator is not easy to remain in the acrylic polymer as a part that becomes the cause of the generation of heated gas (exhaust). As an azo polymerization initiator, 2,2'-azobisisobutyronitrile (hereinafter, sometimes referred to as AIBN), 2,2'-azobis-2-methylbutyronitrile (hereinafter, sometimes referred to as AMBN), 2,2'-azobis(2-methylpropionic acid) dimethyl ester, 4,4'-azobis-4-cyanovaleric acid, etc. can be cited. The amount of the azo polymerization initiator used is preferably 0.01 to 5.0 parts by weight, more preferably 0.05 to 4.0 parts by weight, further preferably 0.1 to 3.0 parts by weight, particularly preferably 0.15 to 3.0 parts by weight, and most preferably 0.20 to 2.0 parts by weight, based on the total amount (100 parts by weight) of the monomer components constituting the acrylic polymer.

[0117] The photopolymerization initiator is preferably used when obtaining an acrylic polymer by active energy ray polymerization. Examples of the photopolymerization initiator include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, and thioxanthone-based photopolymerization initiators.

[0118] Examples of benzoin ether-based photopolymerization initiators include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one, and anisole methyl ether. Examples of acetophenone-based photopolymerization initiators include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, and 4-(tert-butyl)dichloroacetophenone. Examples of α-ketol-based photopolymerization initiators include 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropane-1-one. Examples of aromatic sulfonyl chloride-based photopolymerization initiators include 2-naphthalenesulfonyl chloride. As the photoactive oxime-based photopolymerization initiator, for example, 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime and the like can be cited. As the benzoin-based photopolymerization initiator, for example, benzoin and the like can be cited. As the benzyl-based photopolymerization initiator, for example, benzyl and the like can be cited. As the benzophenone-based photopolymerization initiator, for example, benzophenone, benzoylbenzoic acid, 3,3'dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexylphenylketone and the like can be cited. As the ketal-based photopolymerization initiator, for example, benzyldimethylketal and the like can be cited. As the thioxanthone-based photopolymerization initiator, for example, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone and the like can be cited.

[0119] The amount of the photopolymerization initiator used is preferably 0.01 to 3.0 parts by weight, more preferably 0.015 to 2.0 parts by weight, further preferably 0.02 to 1.5 parts by weight, particularly preferably 0.025 to 1.0 parts by weight, and most preferably 0.03 to 0.50 parts by weight, relative to the total amount (100 parts by weight) of the monomer components constituting the acrylic polymer.

[0120] The acrylic adhesive composition may contain a crosslinking agent. By using a crosslinking agent, the cohesive force of the acrylic adhesive can be increased, and the effect of the present invention can be further demonstrated. The crosslinking agent may be only one kind or two or more kinds.

[0121] As the crosslinking agent, in addition to polyfunctional isocyanate crosslinking agents, epoxy crosslinking agents, melamine crosslinking agents, and peroxide crosslinking agents, urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, carbodiimide crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, amine crosslinking agents, etc. can also be mentioned. Among these, at least one (component c) selected from the group consisting of polyfunctional isocyanate crosslinking agents and epoxy crosslinking agents is preferred in terms of further expressing the effects of the present invention.

[0122] Examples of the polyfunctional isocyanate crosslinking agent include lower aliphatic polyisocyanates such as 1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, and 1,6-hexamethylene diisocyanate; alicyclic polyisocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated toluene diisocyanate, and hydrogenated xylene diisocyanate; and aromatic polyisocyanates such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4′-diphenylmethane diisocyanate, and xylylene diisocyanate. Examples of the polyfunctional isocyanate crosslinking agent include commercially available products such as trimethylolpropane / toluene diisocyanate adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name “CORONATE L”), trimethylolpropane / hexamethylene diisocyanate adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name “CORONATE HL”), trade name “CORONATE HX” (Nippon Polyurethane Industry Co., Ltd.), and trimethylolpropane / xylylene diisocyanate adduct (manufactured by Mitsui Chemicals, Inc., trade name “TAKENATE 110N”).

[0123] Examples of epoxy crosslinking agents (polyfunctional epoxy compounds) include N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidyl aniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and sorbitan. Alcohol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, diglycidyl adipate, diglycidyl phthalate, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. Commercial products such as trade name "TETRAD C" (Mitsubishi Gas Chemical Co., Ltd.) can also be cited as epoxy crosslinking agents.

[0124] The content of the crosslinking agent in the acrylic adhesive composition can be any appropriate content within the range that does not impair the effect of the present invention. As such a content, for example, in terms of further expressing the effect of the present invention, it is preferably 0.1 to 5.0 parts by weight, more preferably 0.2 to 4.5 parts by weight, further preferably 0.3 to 4.0 parts by weight, and particularly preferably 0.4 to 3.5 parts by weight relative to the solid content (100 parts by weight) of the acrylic polymer.

[0125] The acrylic adhesive composition may contain any other appropriate components within the scope of not impairing the effect of the present invention. As such other components, for example, polymer components other than acrylic polymers, crosslinking accelerators, crosslinking catalysts, silane coupling agents, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), antioxidants, inorganic fillers, organic fillers, metal powders, colorants (pigments, dyes, etc.), foils, ultraviolet absorbers, antioxidants, light stabilizers, chain transfer agents, plasticizers, softeners, surfactants, antistatic agents, conductive agents, stabilizers, surface lubricants, leveling agents, anticorrosives, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts, etc. can be cited.

[0126] Another embodiment of the adhesive is a silicone adhesive. As the silicone adhesive, any appropriate silicone adhesive can be used within the range that does not impair the effect of the present invention. As such a silicone adhesive, for example, the known silicone adhesive described in Japanese Patent Publication No. 2014-047280 can be cited. The silicone adhesive may be only one type or may be two or more types.

[0127] The silicone adhesive can be typically formed from a silicone adhesive composition. As the silicone adhesive composition, any appropriate silicone adhesive composition can be used within the range that does not impair the effect of the present invention. As the silicone adhesive composition, for example, a peroxide crosslinking silicone adhesive composition (peroxide curing silicone adhesive composition) and an addition reaction silicone adhesive composition can be cited, and preferably an addition reaction silicone adhesive composition can be cited.

[0128] The silicone adhesive composition typically contains at least one selected from the group consisting of silicone rubber and silicone resin. The content ratio of at least one selected from the group consisting of silicone rubber and silicone resin in the silicone adhesive composition is preferably 50% to 100% by weight, more preferably 70% to 100% by weight, and further preferably 90% to 100% by weight.

[0129] As the silicone rubber, any appropriate silicone rubber can be adopted within a range not impairing the effects of the present invention.

[0130] One embodiment of the silicone rubber includes, for example, a polymer in which diorganosiloxanes (D unit: a bifunctional structural unit "R2SiO") are connected in a straight chain, and specifically, for example, an organopolysiloxane having dimethylsiloxane, methylphenylsiloxane, etc. as main structural units.

[0131] Another embodiment of the silicone rubber includes, for example, silicone rubber having an alkenyl group bonded to a silicon atom, silicone rubber having at least a methyl group, and silicone rubber having a silanol group or a hydrolyzable alkoxysilyl group at a terminal, depending on the type of reaction.

[0132] The weight average molecular weight of the organopolysiloxane in the silicone rubber is preferably 100,000 to 1,000,000, more preferably 150,000 to 1,000,000, further preferably 280,000 to 1,000,000, and particularly preferably 500,000 to 900,000. The weight average molecular weight can be measured by, for example, GPC.

[0133] As the silicone resin, any appropriate silicone resin can be adopted within a range not impairing the effects of the present invention.

[0134] Examples of the silicone resin include: 0.5 " structural unit), Q unit ("SiO2" structural unit), T unit ("RSiO 1.5The organopolysiloxane comprises at least one structural unit selected from the group consisting of a "R2SiO" structural unit), a D unit ("R2SiO" structural unit). It should be noted that R in the above structural units represents a hydrocarbon group or a hydroxyl group, and examples of the hydrocarbon group include aliphatic hydrocarbon groups (alkyl groups such as methyl and ethyl), alicyclic hydrocarbon groups (cycloalkyl groups such as cyclohexyl), and aromatic hydrocarbon groups (aryl groups such as phenyl and naphthyl).

[0135] In the silicone resin, the ratio (molar ratio) of "M unit" to "at least one selected from Q unit, T unit, and D unit" is, for example, "M unit" / "at least one selected from Q unit, T unit, and D unit" (molar ratio) is preferably 0.3 / 1 to 1.5 / 1, more preferably 0.5 / 1 to 1.3 / 1.

[0136] Various functional groups such as a vinyl group may be introduced into the organopolysiloxane in the silicone resin as required. It should be noted that the introduced functional group may also be a functional group capable of undergoing a crosslinking reaction.

[0137] The weight average molecular weight of the organopolysiloxane in the silicone resin is preferably 1,000 or more, more preferably 1,000 to 20,000, and even more preferably 1,500 to 10,000.

[0138] The silicone rubber and the silicone resin may be used together. In this case, the amount of the silicone resin used is preferably 1 to 300 parts by weight, more preferably 10 to 220 parts by weight, and even more preferably 20 to 180 parts by weight, based on 100 parts by weight of the silicone rubber.

[0139] When silicone rubber and silicone resin are used together, the silicone rubber and silicone resin may be in a mixed state where they are simply mixed, or in a condensed state where the silicone rubber and silicone resin react to form a condensate (particularly a partial condensate) by mixing them.

[0140] In order to form a silicone adhesive layer as a cross-linked structure, the silicone adhesive composition preferably contains a cross-linking agent. The cross-linking agent may be only one kind or two or more kinds. As the cross-linking agent, any appropriate cross-linking agent can be used within the range that does not impair the effect of the present invention. As such a cross-linking agent, for example, a siloxane cross-linking agent (silicone cross-linking agent) and a peroxide cross-linking agent can be cited.

[0141] As a siloxane-based crosslinking agent, for example, polyorganohydrogensiloxane having two or more hydrogen atoms bonded to silicon atoms in the molecule can be mentioned. In such polyorganohydrogensiloxane, various organic groups other than hydrogen atoms can also be bonded to the silicon atoms to which hydrogen atoms are bonded. As such organic groups, alkyl groups such as methyl and ethyl, aryl groups such as phenyl, halogenated alkyl groups, etc. can be mentioned. Among these, alkyl groups are preferred, and methyl groups are more preferred from the viewpoint of synthesis and operation. In addition, the skeleton structure of the polyorganohydrogensiloxane can have any skeleton structure of straight chain, branched chain, and cyclic, preferably straight chain.

[0142] Examples of the peroxide-based crosslinking agent include benzoyl peroxide, t-butyl perbenzoate, and dicumyl peroxide.

[0143] The silicone-based adhesive composition may contain additives such as a catalyst, a filler, a plasticizer, an antioxidant, an antistatic agent, a colorant (pigment, dye, etc.) as necessary. The additives may be one or more.

[0144] <2-2. Impregnation process>

[0145] In the impregnation step, the binder is impregnated with the binder by the binder treatment liquid.

[0146] As a method for such impregnation, any appropriate impregnation method can be adopted according to the type of adhesive, etc., within the scope that does not impair the effect of the present invention. It should be noted that in this specification, "impregnating the adhesive treatment liquid into the adhesive" means forming a state in which the adhesive treatment liquid is impregnated into the adhesive contained in the adhesive tape, for example, a state in which at least a part of the adhesive is immersed in the adhesive treatment liquid can be cited. This is because, if at least a part of the adhesive is immersed in the adhesive treatment liquid, the adhesive treatment liquid gradually immerses into the adhesive. Therefore, the adhesive tape can be immersed in the adhesive treatment liquid as a whole, or at least a part of the adhesive tape and at least a part of the adhesive can be immersed in the adhesive treatment liquid.

[0147] In the impregnation step, the binder treatment liquid is preferably subjected to at least one of the following: stirring and ultrasonic irradiation. In the impregnation step, the binder treatment liquid is subjected to at least one of the following: stirring and ultrasonic irradiation, so that the phase-separated binder treatment liquid is in a state where the organic solvent phase is dispersed in the aqueous phase, and the binder can selectively and efficiently absorb and impregnate the organic solvent phase in the binder treatment liquid, thereby improving the separation efficiency of the binder.

[0148] As a stirring method, any appropriate stirring method can be adopted within the range not impairing the effect of the present invention according to the type of adhesive, etc. As for the stirring time, any appropriate stirring time can be adopted within the range not impairing the effect of the present invention according to the type of adhesive, etc.

[0149] As the method of ultrasonic irradiation, any appropriate ultrasonic irradiation method can be adopted within the range that does not impair the effect of the present invention according to the type of adhesive, etc. As for the time of ultrasonic irradiation, any appropriate ultrasonic irradiation time can be adopted within the range that does not impair the effect of the present invention according to the type of adhesive, etc.

[0150] The temperature of the state in which the adhesive is impregnated with the adhesive treatment liquid can be any appropriate temperature within the range that does not impair the effect of the present invention. As such a temperature, in terms of further expressing the effect of the present invention, it is preferably 10°C or more, more preferably 15°C or more, further preferably 20°C or more, further preferably 25°C or more, further preferably 30°C or more, and particularly preferably 35°C or more, and the upper limit is preferably 120°C or less, more preferably 100°C or less, and further preferably 80°C or less.

[0151] In the impregnation step, the binder treatment liquid is preferably heated. In order to further demonstrate the effect of the present invention, as a preferred embodiment of the impregnation step, the binder treatment liquid is heated while being subjected to at least one selected from the group consisting of stirring and ultrasonic irradiation. The heating temperature is preferably 35°C or higher, more preferably 40°C or higher, further preferably 45°C or higher, further preferably 50°C or higher, further preferably 55°C or higher, particularly preferably 60°C or higher, and most preferably 65°C or higher.

[0152] In the impregnation process, in order to further demonstrate the effect of the present invention, the amount of the adhesive treatment liquid used is preferably 100 to 6000 parts by weight, more preferably 200 to 3000 parts by weight, further preferably 200 to 1000 parts by weight, particularly preferably 200 to 800 parts by weight, and most preferably 200 to 400 parts by weight relative to 100 parts by weight of the adhesive tape.

[0153] The impregnation step makes it possible to easily remove the adhesive from the adhesive tape, and also makes it possible to easily recover the base material with contamination and corrosion suppressed for reuse.

[0154] <2-3. Raw material separation process>

[0155] The method for producing a recycled substrate according to an embodiment of the present invention preferably includes a raw material separation step of separating the substrate-derived structure from the adhesive tape after the impregnation step. The "substrate-derived structure" herein refers to the substrate contained in the adhesive tape after the impregnation treatment.

[0156] The raw material separation step can be any method that can separate the structure derived from the substrate from the adhesive tape after the impregnation step, and any appropriate method can be adopted within the scope that does not impair the effect of the present invention. As such a method, it is preferred to add a cleaning liquid to the adhesive tape after the impregnation treatment. Thus, the structure derived from the substrate can be easily separated from the adhesive tape after the impregnation treatment. In the case where a cleaning liquid is added to the adhesive tape after the impregnation treatment, after the impregnation treatment, the adhesive tape can be taken out from the adhesive treatment liquid and the cleaning liquid can be added to the adhesive tape.

[0157] The amount of cleaning liquid added to the impregnation-treated adhesive tape can be any appropriate amount within the range that does not impair the effect of the present invention. Such an amount, for example, is preferably 200 to 10,000 parts by weight, more preferably 500 to 10,000 parts by weight, further preferably 1,000 to 10,000 parts by weight, particularly preferably 1,000 to 5,000 parts by weight, and most preferably 1,000 to 3,000 parts by weight, relative to 100 parts by weight of the adhesive tape.

[0158] By adding a cleaning liquid to the adhesive tape after the impregnation treatment, a mixture of a structure derived from the substrate, a composition derived from the adhesive, and a liquid component (representatively, cleaning water and adhesive treatment liquid) is typically obtained. The structure derived from the substrate is separated from the mixture, and dried and cleaned as needed, so that the separated structure derived from the substrate becomes a reused substrate.

[0159] <2-4. Liquid separation step>

[0160] The method for manufacturing a reused substrate according to an embodiment of the present invention may include a liquid separation step for separating water and an organic solvent from the liquid component (representatively, a cleaning liquid or an adhesive treatment liquid) obtained in the raw material separation step. By including the liquid separation step, water and an organic solvent can be recovered and reused.

[0161] As a method for separating water and an organic solvent, any appropriate method can be adopted within the scope that does not impair the effect of the present invention. Such methods include, for example, separation based on the difference in specific gravity of heterogeneous solvents, separation using an alcohol separation membrane or RO membrane, separation using an alcohol adsorbent, and separation under distillation using the difference in boiling points between water and an organic solvent.

[0162] Examples of the cleaning liquid include water, an organic solvent, a saturated aqueous solution of an organic solvent, and a mixed liquid containing an organic solvent and water in an amount exceeding the saturation amount.

[0163] As the organic solvent that can be used in the cleaning solution, any appropriate organic solvent can be used within the scope that does not impair the effect of the present invention. Examples of such organic solvents include alcohols, hydrocarbons, ketones, esters, ethers, amines, nitriles, carboxylic acids, terpenes, nitro compounds, and halogen compounds. Regarding these organic solvents, the description of the organic solvent in the aforementioned adhesive treatment solution can be cited.

[0164] 《3. Method for producing recycled polymer composition》

[0165] The method for producing a recycled polymer composition according to an embodiment of the present invention is a method for producing a recycled polymer composition from an adhesive tape comprising a substrate and an adhesive, the method comprising an impregnation step of impregnating the adhesive tape with the adhesive treatment liquid according to an embodiment of the present invention for impregnation treatment.

[0166] <3-1. Adhesive tape>

[0167] Regarding the pressure-sensitive adhesive tape, the description in <2-1. Pressure-sensitive adhesive tape> can be cited.

[0168] <3-2. Impregnation process>

[0169] Regarding the impregnation step, the description in <2-2. Impregnation step> can be cited.

[0170] <3-3. Raw material separation process>

[0171] In the method for producing a recycled polymer composition according to an embodiment of the present invention, after the impregnation step, a raw material separation step of separating the composition derived from the adhesive tape is preferably included. Here, the "composition derived from the adhesive tape" refers to the adhesive contained in the adhesive tape after the impregnation treatment.

[0172] The raw material separation step can be any method that can separate the composition derived from the adhesive from the adhesive tape after the impregnation step, and any appropriate method can be adopted within the scope that does not impair the effect of the present invention. As such a method, it is preferred to add a cleaning liquid to the adhesive tape after the impregnation treatment. Thus, the composition derived from the adhesive can be easily separated from the adhesive tape after the impregnation treatment. In the case of adding a cleaning liquid to the adhesive tape after the impregnation treatment, after the impregnation treatment, the adhesive tape can be taken out from the adhesive treatment liquid and the cleaning liquid can be added to the adhesive tape.

[0173] The amount of cleaning liquid added to the impregnation-treated adhesive tape can be any appropriate amount within the range that does not impair the effect of the present invention. Such an amount, for example, is preferably 200 to 10,000 parts by weight, more preferably 500 to 10,000 parts by weight, further preferably 1,000 to 10,000 parts by weight, particularly preferably 1,000 to 5,000 parts by weight, and most preferably 1,000 to 3,000 parts by weight, relative to 100 parts by weight of the adhesive tape.

[0174] By adding a cleaning liquid to the adhesive tape after the impregnation treatment, a mixture of a structure derived from a substrate, a composition derived from an adhesive, and a liquid component (representatively a cleaning liquid and an adhesive treatment liquid) is typically obtained. The composition derived from the adhesive is separated from the mixture, and dried and cleaned as needed, so that the composition derived from the adhesive after separation becomes a recycled polymer composition. For example, when the adhesive after separation is an acrylic adhesive, the recycled polymer composition becomes a recycled acrylic polymer composition containing a recycled acrylic polymer, and when the adhesive after separation is a silicone adhesive, it becomes a recycled silicone polymer composition containing a recycled silicone polymer.

[0175] Examples of the cleaning liquid include water, an organic solvent, a saturated aqueous solution of an organic solvent, and a mixed liquid containing an organic solvent and water in an amount exceeding the saturation amount.

[0176] As the organic solvent that can be used in the cleaning solution, any appropriate organic solvent can be used within the scope that does not impair the effect of the present invention. Examples of such organic solvents include alcohols, hydrocarbons, ketones, esters, ethers, amines, nitriles, carboxylic acids, terpenes, nitro compounds, and halogen compounds. Regarding these organic solvents, the description of the organic solvent in the aforementioned adhesive treatment solution can be cited.

[0177] <3-4. Liquid separation step>

[0178] Regarding the liquid separation step, the description in <2-4. Liquid separation step> can be cited.

[0179] Example

[0180] Hereinafter, the present invention will be specifically described based on Examples, but the present invention is not limited to these Examples at all. It should be noted that the test and evaluation methods in the Examples, etc. are as follows.

[0181] <Calculation of the relative distance Ra between the Hansen solubility parameter value of water contained in the binder treatment liquid and the Hansen solubility parameter value of the organic solvent contained in the binder treatment liquid>

[0182] The relative distance Ra is calculated according to the following formula.

[0183] Ra=√[4(δD2-δD1) 2 +(δP2-δP1) 2 +(δH2-δH1) 2 ]

[0184] δD1: Energy of dispersion force between molecules based on organic solvent (unit: MPa) 0.5 )

[0185] δD2: Energy based on the dispersion force between water molecules (unit: MPa) 0.5 )

[0186] δP1: Energy of dipole interaction between molecules based on organic solvent (unit: MPa) 0.5 )

[0187] δP2: Energy based on dipole interactions between water molecules (in MPa) 0.5 )

[0188] δH1: Energy of hydrogen bonds between molecules based on organic solvents (in MPa) 0.5 )

[0189] δH2: Energy of hydrogen bonds between water molecules (in MPa) 0.5 )

[0190] <Evaluation of compatibility of adhesive treatment liquid>

[0191] In a screw-capped tube (30 mL), an organic solvent, water and an alkaline compound were added in the type and ratio used to prepare the adhesive treatment liquid to be evaluated. After confirming that the alkaline compound was completely dissolved, the mixture was shaken and stirred for more than 10 times. A suspension immediately after stirring was evaluated as "phase separation", and a transparent one was evaluated as "miscible".

[0192] <Evaluation of water solubility of recycled polymer composition>

[0193] The impregnated adhesive tape sample was placed in the washing water and stirred for 3 minutes or more. The sample in which the recycled polymer composition did not dissolve in the washing water after stirring but gradually floated in the original shape was evaluated as "insoluble", and the sample in which the recycled polymer composition dissolved in the washing water was evaluated as "dissolved".

[0194] <Evaluation of Ease of Recovery Using Difference in Specific Gravity of Recycled Polymer Compositions>

[0195] The adhesive tape sample after impregnation treatment is placed in the washing water and stirred for more than 3 minutes. After stirring, the recycled polymer composition does not dissolve in the washing water and is peeled off from the substrate in its original shape and gradually floats, which is evaluated as "can" be easily recovered, and the recycled polymer composition is dissolved in the washing water and separated from the substrate, which is evaluated as "cannot" be easily recovered. Here, the substrate of the adhesive tape sample used in the embodiment and comparative example is a PET substrate with a specific gravity of more than 1, so it settles in the washing water. It should be noted that in the case of the above-mentioned "cannot" evaluation, the recycled polymer composition dissolves in the washing water, so there may be problems such as contamination of the washing water caused by the recycled polymer composition, and contamination of the substrate caused by the recycled polymer composition dissolved in the washing water re-attaching to the substrate.

[0196] <Appearance evaluation of recycled substrate>

[0197] The recycled base material separated in the raw material separation step is collected, air-dried, and visually confirmed. Light is transmitted or reflected, and those that can be confirmed to be turbid are recorded as "whitened", and those that are not turbid are recorded as "transparent". It should be noted that the whitening phenomenon becomes an indicator of the degree of adhesion of pollutants to the recycled base material and the corrosion of the recycled base material surface.

[0198] [Example 1]

[0199] An acrylic pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation, trade name "No. 3195MS", after foaming) was cut into a size of 20 mm x 20 mm to prepare a pressure-sensitive adhesive tape sample.

[0200] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 11.8% / 12.0% / 76.2% (volume ratio) to give a concentration of 3 wt %, thereby preparing a binder treatment liquid (1).

[0201] The adhesive tape sample and the adhesive treatment liquid (1) were placed in a screw-capped tube (30 mL) at a weight ratio of 1:2. In the screw-capped tube, the adhesive of the adhesive tape sample was impregnated with the adhesive treatment liquid (1).

[0202] The screw-capped tube was placed in an ultrasonic stirrer (manufactured by As One Corporation, trade name "VS-F100", frequency = 50 kHz), and the mixture was stirred at room temperature (25° C.) for 60 minutes under ultrasonic irradiation.

[0203] Afterwards, the adhesive tape sample is taken out from the adhesive treatment liquid (1), immersed in washing water, and stirred by hand for about 3 minutes, so that the recycled acrylic polymer composition derived from the adhesive possessed by the adhesive tape sample is peeled off from the recycled substrate derived from the substrate possessed by the adhesive tape sample, and separated due to the difference in specific gravity in the washing water. The recycled acrylic polymer composition floating in the washing water is recovered together with the supernatant by overflow based on the excess addition of water, and its solid content is captured by a filter, thereby obtaining the recycled acrylic polymer composition (1) derived from the adhesive possessed by the adhesive tape sample. In addition, the recycled substrate derived from the substrate possessed by the adhesive tape sample settles in the washing water, and is lifted up after the recycled acrylic polymer composition is recovered, thereby obtaining the recycled substrate (1) derived from the substrate possessed by the adhesive tape sample.

[0204] The results are shown in Table 1.

[0205] [Example 2]

[0206] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 23.0% / 11.8% / 65.2% (volume ratio) to a concentration of 3 wt %, thereby preparing a binder treatment liquid (2).

[0207] A recycled substrate (2) and a recycled acrylic polymer composition (2) were obtained in the same manner as in Example 1 except that the adhesive treatment liquid (2) was used instead of the adhesive treatment liquid (1).

[0208] The results are shown in Table 1.

[0209] [Example 3]

[0210] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 33.8% / 11.5% / 54.7% (volume ratio) to a concentration of 3 wt %, thereby preparing a binder treatment liquid (3).

[0211] A recycled substrate (3) and a recycled acrylic polymer composition (3) were obtained in the same manner as in Example 1 except that the adhesive treatment liquid (3) was used instead of the adhesive treatment liquid (1).

[0212] The results are shown in Table 1.

[0213] [Example 4]

[0214] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 44.1% / 11.3% / 44.6% (volume ratio) to give a concentration of 3 wt %, thereby preparing a binder treatment liquid (4).

[0215] A recycled substrate (4) and a recycled acrylic polymer composition (4) were obtained in the same manner as in Example 1 except that the adhesive treatment liquid (4) was used instead of the adhesive treatment liquid (1).

[0216] The results are shown in Table 1.

[0217] [Example 5]

[0218] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 63.5% / 10.8% / 25.7% (volume ratio) to give a concentration of 3 wt %, thereby preparing a binder treatment liquid (5).

[0219] A recycled substrate (5) and a recycled acrylic polymer composition (5) were obtained in the same manner as in Example 1 except that the adhesive treatment liquid (5) was used instead of the adhesive treatment liquid (1).

[0220] The results are shown in Table 1.

[0221] [Example 6]

[0222] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 23.0% / 11.8% / 65.2% (volume ratio) to a concentration of 1.5% by weight to prepare a binder treatment liquid (6).

[0223] A recycled substrate (6) and a recycled acrylic polymer composition (6) were obtained in the same manner as in Example 1 except that the adhesive treatment liquid (6) was used instead of the adhesive treatment liquid (1) and the stirring time in the ultrasonic stirrer was changed to 90 minutes.

[0224] The results are shown in Table 1.

[0225] [Example 7]

[0226] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 23.0% / 11.8% / 65.2% (volume ratio) to give a concentration of 2.0% by weight to prepare a binder treatment liquid (7).

[0227] A recycled substrate (7) and a recycled acrylic polymer composition (7) were obtained in the same manner as in Example 1 except that the adhesive treatment liquid (7) was used instead of the adhesive treatment liquid (1).

[0228] The results are shown in Table 1.

[0229] [Example 8]

[0230] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 33.8% / 11.5% / 54.7% (volume ratio) to give a concentration of 1.5% by weight to prepare a binder treatment liquid (8).

[0231] A recycled substrate (8) and a recycled acrylic polymer composition (8) were obtained in the same manner as in Example 1 except that the adhesive treatment liquid (8) was used instead of the adhesive treatment liquid (1) and the stirring time in the ultrasonic stirrer was changed to 90 minutes.

[0232] The results are shown in Table 1.

[0233] [Example 9]

[0234] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 33.8% / 11.5% / 54.7% (volume ratio) to a concentration of 2.0% by weight to prepare a binder treatment liquid (9).

[0235] A recycled substrate (9) and a recycled acrylic polymer composition (9) were obtained in the same manner as in Example 1 except that the adhesive treatment liquid (9) was used instead of the adhesive treatment liquid (1).

[0236] The results are shown in Table 1.

[0237] [Comparative Example 1]

[0238] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 62.1% / 21.2% / 16.8% (volume ratio) to a concentration of 3.0% by weight to prepare a binder treatment liquid (C1).

[0239] A recycled substrate (C1) was obtained in the same manner as in Example 1 except that the binder treatment liquid (C1) was used instead of the binder treatment liquid (1).

[0240] The results are shown in Table 2.

[0241] [Comparative Example 2]

[0242] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 60.7% / 31.1% / 8.2% (volume ratio) to a concentration of 3.0% by weight to prepare a binder treatment liquid (C2).

[0243] A recycled substrate (C2) was obtained in the same manner as in Example 1 except that the binder treatment liquid (C2) was used instead of the binder treatment liquid (1).

[0244] The results are shown in Table 2.

[0245] [Comparative Example 3]

[0246] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 32.2% / 33.0% / 34.8% (volume ratio) to a concentration of 3.0% by weight to prepare a binder treatment liquid (C3).

[0247] A recycled substrate (C3) was obtained in the same manner as in Example 1 except that the binder treatment liquid (C3) was used instead of the binder treatment liquid (1).

[0248] The results are shown in Table 2.

[0249] [Comparative Example 4]

[0250] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 11.2% / 34.4% / 54.4% (volume ratio) to a concentration of 3.0% by weight to prepare a binder treatment liquid (C4).

[0251] A recycled substrate (C4) was obtained in the same manner as in Example 1 except that the binder treatment liquid (C4) was used instead of the binder treatment liquid (1).

[0252] The results are shown in Table 2.

[0253] [Comparative Example 5]

[0254] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 10.0% / 81.9% / 8.1% (volume ratio) to a concentration of 3.0% by weight to prepare a binder treatment liquid (C5).

[0255] A recycled substrate (C5) was obtained in the same manner as in Example 1 except that the binder treatment liquid (C5) was used instead of the binder treatment liquid (1).

[0256] The results are shown in Table 2.

[0257] [Example 10]

[0258] An acrylic pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation, trade name "No. 3195MS", after foaming) was cut into a size of 20 mm x 20 mm to prepare a pressure-sensitive adhesive tape sample.

[0259] Potassium hydroxide was added to a mixed solution of 1-butanol / water = 12.1% / 87.9% (volume ratio) to a concentration of 2.6% by weight to prepare a binder treatment liquid (10).

[0260] The adhesive tape sample and the adhesive treatment liquid (10) were placed in a screw-capped tube (30 mL) at a weight ratio of 1:5. In the screw-capped tube, the adhesive of the adhesive tape sample was impregnated with the adhesive treatment liquid (10).

[0261] The screw-capped tube was placed in an ultrasonic stirrer (manufactured by As One Corporation, trade name "VS-F100", frequency = 50 kHz), and the mixture was stirred at room temperature (25° C.) for 60 minutes under ultrasonic irradiation.

[0262] After that, the adhesive tape sample is taken out from the adhesive treatment liquid (10), immersed in washing water, and stirred by hand for about 3 minutes, so that the recycled acrylic polymer composition derived from the adhesive possessed by the adhesive tape sample is peeled off from the recycled substrate derived from the substrate possessed by the adhesive tape sample, and separated due to the difference in specific gravity in the washing water. The recycled acrylic polymer composition floating in the washing water is recovered together with the supernatant by overflow based on the excess addition of water, and its solid content is captured by a filter, thereby obtaining the recycled acrylic polymer composition (10) derived from the adhesive possessed by the adhesive tape sample. In addition, the recycled substrate derived from the substrate possessed by the adhesive tape sample settles in the washing water, and is lifted up after the recycled acrylic polymer composition is recovered, thereby obtaining the recycled substrate (10) derived from the substrate possessed by the adhesive tape sample.

[0263] The results are shown in Table 3.

[0264] [Example 11]

[0265] An acrylic pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation, trade name "No. 3195MS", after foaming) was cut into a size of 20 mm x 20 mm to prepare a pressure-sensitive adhesive tape sample.

[0266] The adhesive tape sample and the adhesive treatment liquid (10) were placed in a screw-capped tube (30 mL) at a weight ratio of 1:5. In the screw-capped tube, the adhesive of the adhesive tape sample was impregnated with the adhesive treatment liquid (10).

[0267] Water preheated to 70° C. and a screw-capped tube were placed in an ultrasonic stirrer (manufactured by As One Corporation, trade name “VS-F100”, frequency = 50 kHz), and the mixture was stirred for 30 minutes under ultrasonic irradiation.

[0268] The subsequent steps were carried out in the same manner as in Example 10 to obtain a recycled substrate (11) and a recycled acrylic polymer composition (11).

[0269] The results are shown in Table 3.

[0270] [Example 12]

[0271] An acrylic pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation, trade name "No. 3195MS", after foaming) was cut into a size of 20 mm x 20 mm to prepare a pressure-sensitive adhesive tape sample.

[0272] Potassium hydroxide was added to a mixed solution of 1-butanol / water = 12.1% / 87.9% (volume ratio) to give a concentration of 2.6% by weight to prepare a binder treatment liquid (12).

[0273] In a screw-capped tube (30 mL), the adhesive tape sample and the adhesive treatment solution (12) were added in a weight ratio of 1:5, and then shaken and stirred for more than 10 times. In the screw-capped tube, the adhesive of the adhesive tape sample was impregnated with the adhesive treatment solution (12), and the adhesive treatment solution (12) became turbid.

[0274] The screw cap tube was placed in a water bath set at 70°C, taken out every 5 minutes, shaken and stirred for 10 times or more, and placed in the water bath again. These operations were performed until the recycled acrylic polymer (12) derived from the adhesive in the adhesive treatment liquid (12) was peeled off from the recycled substrate (12) derived from the substrate of the adhesive tape sample. The total treatment time was 30 minutes.

[0275] The subsequent steps were carried out in the same manner as in Example 10 to obtain a recycled substrate (12) and a recycled acrylic polymer composition (12).

[0276] The results are shown in Table 3.

[0277] [Example 13]

[0278] Potassium hydroxide was added to a mixed solution of 1-pentanol / water = 11.9% / 88.1% (volume ratio) to give a concentration of 2.6% by weight to prepare a binder treatment liquid (13).

[0279] A recycled substrate (13) and a recycled acrylic polymer composition (13) were obtained in the same manner as in Example 12 except that the adhesive treatment liquid (13) was used instead of the adhesive treatment liquid (12).

[0280] It should be noted that the total processing time is 40 minutes.

[0281] The results are shown in Table 3.

[0282] [Example 14]

[0283] Potassium hydroxide was added to a mixed solution of 1-heptanol / water = 11.9% / 88.1% (volume ratio) to give a concentration of 2.6% by weight to prepare a binder treatment liquid (14).

[0284] A recycled substrate (14) and a recycled acrylic polymer composition (14) were obtained in the same manner as in Example 12 except that the adhesive treatment liquid (14) was used instead of the adhesive treatment liquid (12).

[0285] It should be noted that the total processing time was 140 minutes.

[0286] The results are shown in Table 3.

[0287] [Example 15]

[0288] Potassium hydroxide was added to a mixed solution of 2-ethylhexanol / water = 11.8% / 88.2% (volume ratio) to give a concentration of 2.6% by weight to prepare a binder treatment liquid (15).

[0289] A recycled substrate (15) and a recycled acrylic polymer composition (15) were obtained in the same manner as in Example 12 except that the adhesive treatment liquid (15) was used instead of the adhesive treatment liquid (12).

[0290] It should be noted that the total processing time is 180 minutes.

[0291] The results are shown in Table 3.

[0292] [Example 16]

[0293] Potassium hydroxide was added to a mixed solution of benzyl alcohol / water = 9.7% / 90.3% (volume ratio) to give a concentration of 2.6% by weight to prepare a binder treatment liquid (16).

[0294] A recycled substrate (16) and a recycled acrylic polymer composition (16) were obtained in the same manner as in Example 12 except that the adhesive treatment liquid (16) was used instead of the adhesive treatment liquid (12).

[0295] It should be noted that the total processing time is 30 minutes.

[0296] The results are shown in Table 3.

[0297] [Example 17]

[0298] Sodium hydroxide was added to a mixed solution of 1-butanol / water = 12.1% / 87.9% (volume ratio) to give a concentration of 2.6% by weight to prepare a binder treatment liquid (17).

[0299] A recycled substrate (17) and a recycled acrylic polymer composition (17) were obtained in the same manner as in Example 12 except that the adhesive treatment liquid (17) was used instead of the adhesive treatment liquid (12).

[0300] It should be noted that the total processing time is 25 minutes.

[0301] The results are shown in Table 3.

[0302] [Example 18]

[0303] An acrylic pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation, trade name "RP207") was cut into a size of 20 mm x 20 mm to prepare a pressure-sensitive adhesive tape sample.

[0304] Potassium hydroxide was added to a mixed solution of 1-butanol / water = 12.1% / 87.9% (volume ratio) to give a concentration of 3% by weight, thereby preparing a binder treatment liquid (18).

[0305] The adhesive tape sample and the adhesive treatment solution (18) were placed in a screw-capped tube (30 mL) at a weight ratio of 1:5, and then shaken and stirred for 10 or more times. In the screw-capped tube, the adhesive of the adhesive tape sample was impregnated with the adhesive treatment solution (18), and the adhesive treatment solution (18) became turbid.

[0306] The screw cap tube was placed in a water bath set at 70°C, taken out every 5 minutes, shaken and stirred 10 times or more, and placed in the water bath again. These operations were performed until the recycled acrylic polymer (18) derived from the adhesive in the adhesive treatment liquid (18) was peeled off from the recycled base material (18) derived from the base material of the adhesive tape sample.

[0307] The subsequent steps were carried out in the same manner as in Example 10 to obtain a recycled substrate (18) and a recycled acrylic polymer composition (18).

[0308] It should be noted that the total processing time is 30 minutes.

[0309] The results are shown in Table 3.

[0310] [Example 19]

[0311] Potassium hydroxide was added to a mixed solution of benzyl alcohol / water = 9.7% / 90.3% (volume ratio) to give a concentration of 3 wt %, thereby preparing a binder treatment liquid (19).

[0312] A recycled substrate (19) and a recycled acrylic polymer composition (19) were obtained in the same manner as in Example 18 except that the adhesive treatment liquid (19) was used instead of the adhesive treatment liquid (18).

[0313] It should be noted that the total processing time is 35 minutes.

[0314] The results are shown in Table 3.

[0315] [Example 20]

[0316] A silicone-based pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation, trade name "No. 923S") was cut into a size of 10 mm x 10 mm to prepare a pressure-sensitive adhesive tape sample.

[0317] Potassium hydroxide was added to a mixed solution of 1-butanol / water = 12.1% / 87.9% (volume ratio) to give a concentration of 3 wt %, thereby preparing a binder treatment liquid (20).

[0318] The adhesive tape sample and the adhesive treatment solution (20) were placed in a screw-capped tube (30 mL) at a weight ratio of 1:10, and the mixture was shaken and stirred for 10 or more times. The adhesive of the adhesive tape sample was impregnated into the adhesive treatment solution (20) in the screw-capped tube, and the adhesive treatment solution (20) became turbid.

[0319] The screw cap tube was placed in a water bath set at 70°C, taken out every 5 minutes, shaken and stirred for more than 10 times, and placed in the water bath again. These operations were performed until the recycled silicone polymer (20) derived from the adhesive in the adhesive treatment liquid (20) was peeled off from the recycled substrate (20) derived from the substrate of the adhesive tape sample. The total treatment time was 230 minutes.

[0320] The subsequent steps were carried out in the same manner as in Example 10 to obtain a recycled substrate (20) and a recycled silicone-based polymer composition (20).

[0321] The results are shown in Table 4.

[0322] [Example 21]

[0323] An acrylic pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation, trade name "RP108C") was cut into a size of 10 mm x 10 mm to prepare a pressure-sensitive adhesive tape sample.

[0324] Potassium hydroxide was added to a mixed solution of 1-butanol / water = 12.1% / 87.9% (volume ratio) to a concentration of 3 wt %, thereby preparing a binder treatment liquid (21).

[0325] The adhesive tape sample and the adhesive treatment solution (21) were placed in a screw-capped tube (30 mL) at a weight ratio of 1:10, and the mixture was shaken and stirred for 10 or more times. The adhesive of the adhesive tape sample was impregnated into the adhesive treatment solution (21) in the screw-capped tube, and the adhesive treatment solution (21) became turbid.

[0326] The screw cap tube was placed in a water bath set at 70°C, taken out every 5 minutes, shaken and stirred for more than 10 times, and placed in the water bath again. These operations were performed until the recycled acrylic polymer (21) derived from the adhesive in the adhesive treatment liquid (21) was peeled off from the recycled substrate (21) derived from the substrate of the adhesive tape sample. The total treatment time was 30 minutes.

[0327] The subsequent steps were carried out in the same manner as in Example 10 to obtain a recycled substrate (21) and a recycled acrylic polymer composition (21).

[0328] The results are shown in Table 4.

[0329] [Example 22]

[0330] An acrylic pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation, trade name "SPV-A-6050") was cut into a size of 10 mm x 10 mm to prepare a pressure-sensitive adhesive tape sample.

[0331] Potassium hydroxide was added to a mixed solution of 1-butanol / water = 12.1% / 87.9% (volume ratio) to a concentration of 3 wt %, thereby preparing a binder treatment liquid (22).

[0332] The adhesive tape sample and the adhesive treatment solution (22) were placed in a screw-capped tube (30 mL) at a weight ratio of 1:10, and the mixture was shaken and stirred for 10 or more times. The adhesive of the adhesive tape sample was impregnated into the adhesive treatment solution (22) in the screw-capped tube, and the adhesive treatment solution (22) became turbid.

[0333] The screw cap tube was placed in a water bath set at 70°C, taken out every 5 minutes, shaken and stirred for more than 10 times, and placed in the water bath again. These operations were performed until the recycled acrylic polymer (22) derived from the adhesive in the adhesive treatment liquid (22) was peeled off from the recycled substrate (22) derived from the substrate of the adhesive tape sample. The total treatment time was 320 minutes.

[0334] The subsequent steps were carried out in the same manner as in Example 10 to obtain a recycled substrate (22) and a recycled acrylic polymer composition (22).

[0335] The results are shown in Table 4.

[0336] [Example 23]

[0337] An adhesive tape sample was prepared by attaching 1 g of an acrylic adhesive tape (manufactured by Nitto Denko Corporation, trade name "No. 5000NS") to a SUS304BA plate by finger pressure.

[0338] Potassium hydroxide was added to a mixed solution of 1-butanol / water = 12.1% / 87.9% (volume ratio) to give a concentration of 3 wt %, thereby preparing a binder treatment liquid (23).

[0339] The adhesive tape sample and the adhesive treatment solution (23) were placed in a screw-capped tube (30 mL) at a weight ratio of 1:20, and then shaken and stirred for 10 or more times. In the screw-capped tube, the adhesive of the adhesive tape sample was impregnated with the adhesive treatment solution (23), and the adhesive treatment solution (23) became turbid.

[0340] The screw cap tube was placed in a water bath set at 70°C, taken out every 5 minutes, shaken and stirred for more than 10 times, and placed in the water bath again. These operations were performed until the recycled acrylic polymer (23) derived from the adhesive in the adhesive treatment liquid (23) was peeled off from the SUS304BA plate of the adhesive tape sample. The total treatment time was 95 minutes.

[0341] The subsequent steps were carried out in the same manner as in Example 10 to obtain a recycled acrylic polymer composition (23).

[0342] The results are shown in Table 4.

[0343] [Example 24]

[0344] An acrylic pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation, trade name "No. 3195MS", after foaming) was cut into pieces using a grinder. The size is about the same as that of the adhesive tape sample.

[0345] Potassium hydroxide was added to a mixed solution of 1-butanol / water = 12.1% / 87.9% (volume ratio) to give a concentration of 3 wt %, thereby preparing a binder treatment liquid (24).

[0346] The adhesive tape sample and the adhesive treatment liquid (24) are placed in a polymerization flask (1 L) in a weight ratio of 1:20. In the polymerization flask, the adhesive of the adhesive tape sample is immersed in the adhesive treatment liquid (24). The polymerization flask is placed in a water bath pre-set to 70° C. and heated, and stirred at 735 rpm with a propeller blade. These operations are performed until the recycled acrylic polymer (24) derived from the adhesive in the adhesive treatment liquid (24) is peeled off from the recycled substrate (24) derived from the substrate possessed by the adhesive tape sample. The total treatment time is 25 minutes.

[0347] The subsequent steps were carried out in the same manner as in Example 10 to obtain a recycled substrate (24) and a recycled acrylic polymer composition (24).

[0348] The results are shown in Table 4.

[0349] [Example 25]

[0350] Potassium hydroxide was added to a mixed solution of 1-butanol / water = 12.1% / 87.9% (volume ratio) to give a concentration of 1 wt % to prepare a binder treatment liquid (25).

[0351] A recycled substrate (25) and a recycled acrylic polymer composition (25) were obtained in the same manner as in Example 24 except that the adhesive treatment liquid (25) was used instead of the adhesive treatment liquid (24).

[0352] It should be noted that the total processing time is 40 minutes.

[0353] The results are shown in Table 4.

[0354] [Example 26]

[0355] Potassium hydroxide was added to a mixed solution of 1-butanol / water = 12.1% / 87.9% (volume ratio) to a concentration of 0.5% by weight to prepare a binder treatment liquid (26).

[0356] A recycled substrate (26) and a recycled acrylic polymer composition (26) were obtained in the same manner as in Example 24 except that the adhesive treatment liquid (26) was used instead of the adhesive treatment liquid (24).

[0357] It should be noted that the total processing time is 70 minutes.

[0358] The results are shown in Table 4.

[0359] [Example 27]

[0360] An acrylic pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation, trade name "No. 3195MS", after foaming) was cut into pieces using a grinder. The size is about the same as that of the adhesive tape sample.

[0361] Potassium hydroxide was added to a mixed solution of 1-butanol / water = 12.1% / 87.9% (volume ratio) to give a concentration of 3 wt %, thereby preparing a binder treatment liquid (27).

[0362] The adhesive tape sample and the adhesive treatment liquid (27) preheated to 70° C. were placed in a barrel (20 L) at a weight ratio of 1:5. In the barrel, the adhesive of the adhesive tape sample was immersed in the adhesive treatment liquid (27).

[0363] The drum was stirred by rotating the drum at 1 rpm for 30 minutes using a drum shaker apparatus (Mazemazeman manufactured by Misugi Co., Ltd.).

[0364] The subsequent steps were carried out in the same manner as in Example 10 to obtain a recycled substrate (27) and a recycled acrylic polymer composition (27).

[0365] The results are shown in Table 4.

[0366] [Example 28]

[0367] An acrylic pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation, trade name "No. 3195MS", after foaming) was cut into pieces using a grinder. The size is about the same as that of the adhesive tape sample.

[0368] Potassium hydroxide was added to a mixed solution of 1-butanol / water = 12.1% / 87.9% (volume ratio) to give a concentration of 3 wt %, thereby preparing a binder treatment liquid (28).

[0369] In a polymerization kettle (20 L), an adhesive tape sample and an adhesive treatment liquid (28) were added in a weight ratio of 1:5. In the polymerization kettle, the adhesive of the adhesive tape sample was immersed in the adhesive treatment liquid (28). The heat medium setting temperature of the polymerization kettle was set to 70° C., and the blade in the polymerization kettle was stirred at 50 rpm for 30 minutes.

[0370] The subsequent steps were carried out in the same manner as in Example 10 to obtain a recycled substrate (28) and a recycled acrylic polymer composition (28).

[0371] The results are shown in Table 4.

[0372] [Example 29]

[0373] An acrylic pressure-sensitive adhesive tape (manufactured by Nitto Denko Corporation, trade name "No. 3195MS", after foaming) was cut into pieces using a grinder. The size is about the same as that of the adhesive tape sample.

[0374] Potassium hydroxide was added to a mixed solution of 1-butanol / water = 12.1% / 87.9% (volume ratio) to give a concentration of 3% by weight, thereby preparing a binder treatment liquid (29).

[0375] The adhesive tape sample and the adhesive treatment liquid (29) were placed in a glass container (10 L) at a weight ratio of 1:5. In the glass container, the adhesive of the adhesive tape sample was immersed in the adhesive treatment liquid (29).

[0376] A glass container was placed in a slot-type ultrasonic transmitter (manufactured by KAIJO Corporation, model: 70110 / 75kHz+modulation) and immersed in water heated to 60° C. A horn-type ultrasonic transmitter (manufactured by KAIJO Corporation, model: 6281A / 19.5kHz) was further installed from the top of the glass container to irradiate ultrasonic waves for 150 minutes.

[0377] The subsequent steps were carried out in the same manner as in Example 10 to obtain a recycled substrate (29) and a recycled acrylic polymer composition (29).

[0378] The results are shown in Table 4.

[0379] [Comparative Example 6]

[0380] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 62.1% / 21.2% / 16.8% (volume ratio) to a concentration of 2.6% by weight to prepare a binder treatment liquid (C6).

[0381] A recycled substrate (C6) was obtained in the same manner as in Example 12 except that the binder treatment liquid (C6) was used instead of the binder treatment liquid (12).

[0382] The results are shown in Table 5.

[0383] [Comparative Example 7]

[0384] Sodium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 62.1% / 21.2% / 16.8% (volume ratio) to a concentration of 2.6% by weight to prepare a binder treatment liquid (C7).

[0385] A recycled substrate (C7) was obtained in the same manner as in Example 12 except that the binder treatment liquid (C7) was used instead of the binder treatment liquid (12).

[0386] The results are shown in Table 5.

[0387] [Comparative Example 8]

[0388] Potassium hydroxide was added to a mixed solution of isopropyl alcohol / water = 12.5% / 87.5% (volume ratio) to a concentration of 2.6% by weight to prepare a binder treatment liquid (C8).

[0389] A recycled substrate (C8) was obtained in the same manner as in Example 12 except that the binder treatment liquid (C8) was used instead of the binder treatment liquid (12).

[0390] The results are shown in Table 5.

[0391] [Comparative Example 9]

[0392] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 22.5% / 23.0% / 54.6% (volume ratio) to a concentration of 2.6% by weight to prepare a binder treatment liquid (C9).

[0393] A recycled substrate (C9) was obtained in the same manner as in Example 12 except that the binder treatment liquid (C9) was used instead of the binder treatment liquid (12).

[0394] The results are shown in Table 5.

[0395] [Comparative Example 10]

[0396] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 62.1% / 21.2% / 16.8% (volume ratio) to a concentration of 3 wt %, thereby preparing a binder treatment liquid (C10).

[0397] A recycled substrate (C10) was obtained in the same manner as in Example 18 except that the binder treatment liquid (C10) was used instead of the binder treatment liquid (18).

[0398] The results are shown in Table 5.

[0399] [Comparative Example 11]

[0400] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 62.1% / 21.2% / 16.8% (volume ratio) to a concentration of 3 wt %, thereby preparing a binder treatment liquid (C11).

[0401] The same procedure as in Example 23 was carried out except that the binder treatment liquid (C11) was used instead of the binder treatment liquid (23).

[0402] The results are shown in Table 5.

[0403] [Comparative Example 12]

[0404] Potassium hydroxide was added to a mixed solution of isopropyl alcohol / water = 56.1% / 43.9% (volume ratio) to a concentration of 3 wt %, thereby preparing a binder treatment liquid (C12).

[0405] The same procedures as in Example 23 were carried out except that the binder treatment liquid (C12) was used instead of the binder treatment liquid (23).

[0406] The results are shown in Table 5.

[0407] [Comparative Example 13]

[0408] Potassium hydroxide was added to a mixed solution of 1-butanol / methanol / water = 62.1% / 21.2% / 16.8% (volume ratio) to a concentration of 3 wt %, thereby preparing a binder treatment liquid (C13).

[0409] The same procedures as in Example 24 were carried out except that the binder treatment liquid (C13) was used instead of the binder treatment liquid (24).

[0410] The results are shown in Table 5.

[0411] [Comparative Example 14]

[0412] Potassium hydroxide was added to a mixed solution of isopropyl alcohol / water = 56.1% / 43.9% (volume ratio) to a concentration of 3 wt %, thereby preparing a binder treatment liquid (C14).

[0413] The same procedures as in Example 24 were carried out except that the binder treatment liquid (C14) was used instead of the binder treatment liquid (24).

[0414] The results are shown in Table 5.

[0415] [Table 1]

[0416]

[0417] [Table 2]

[0418]

[0419] [Table 3]

[0420]

[0421] [Table 4]

[0422]

[0423] [Table 5]

[0424]

[0425] In the examples, the recycling of the recycled polymer composition is "able". It is speculated that this is because an adhesive treatment liquid whose compatibility is evaluated as "phase separation" is used, so water is not easy to penetrate into the adhesive possessed by the adhesive tape sample, and mainly undergoes an ester exchange reaction. Therefore, the recycled polymer composition is "insoluble" in water and "can" be recycled. In addition, the amount of alkaline compounds and organic solvents in the adhesive treatment liquid used in the examples is less than that of the adhesive treatment liquid used in the comparative example, so the load on the environment is small. Furthermore, in the examples, the appearance of the recycled substrate is evaluated as "0". It is speculated that this is because, as mentioned above, the recycled polymer composition derived from the adhesive possessed by the adhesive tape sample is "insoluble" in water and "can" be recycled, that is, the recycled polymer composition can be peeled off from the substrate and float in the washing water, so the situation where the recycled polymer composition is re-attached to the substrate is suppressed.

[0426] On the other hand, in the comparative example, the recycling of the recycled polymer composition was "unable". It is speculated that this is because an adhesive treatment liquid with a compatibility evaluation of "compatible" was used, so water infiltrated into the adhesive possessed by the adhesive tape sample, and an ester exchange reaction and a saponification reaction were carried out. Therefore, the recycled polymer composition "dissolved" in water and could not be recycled. In addition, the amount of alkaline compounds and organic solvents in the adhesive treatment liquid used in the comparative example is greater than that of the adhesive treatment liquid used in the embodiment, so the load on the environment is large. Furthermore, in the comparative example, the appearance of the recycled substrate was evaluated as "×". It is speculated that this is because, as mentioned above, the recycled polymer composition derived from the adhesive possessed by the adhesive tape sample "dissolved" in water and "could not" be recycled, that is, the recycled polymer composition dissolved in the washing water and separated from the substrate, so the recycled polymer composition dissolved in the washing water will re-attach to the substrate. In addition, when the recycled polymer composition is dissolved in the washing water, problems such as contamination of the washing water caused by the recycled polymer composition may occur.

[0427] Industrial Applicability

[0428] The adhesive treatment liquid according to the embodiment of the present invention can be effectively used for recycling a large amount of waste adhesive tapes generated at, for example, a production site of electronic components or optical components.

Claims

1. An adhesive treatment liquid, which is an adhesive treatment liquid for treating an adhesive, The adhesive treatment liquid comprises water, an organic solvent and an alkaline compound, The organic solvent and the water form a phase-separated state.

2. The binder treatment liquid according to claim 1, wherein The concentration of the alkaline compound in the binder treatment liquid is 0.001 wt % to 50 wt %.

3. The binder treatment liquid according to claim 1, wherein The relative distance Ra between the Hansen solubility parameter value of the water and the Hansen solubility parameter value of the organic solvent is greater than 24, Among them, the relative distance Ra is calculated using the following formula: Ra=√[4(δD2-δD1) 2 +(δP2-δP1) 2 +(δH2-δH1) 2 ] δD1: Energy of dispersion force between molecules based on organic solvent, unit is MPa 0.5 , δD2: Energy based on the dispersion force between water molecules, unit is MPa 0.5 , δP1: Energy of dipole interaction between molecules based on organic solvent, unit is MPa 0.5 , δP2: Energy based on dipole interactions between water molecules, in MPa 0.5 , δH1: Energy of hydrogen bonds between molecules based on organic solvents, in MPa 0.5 , δH2: Energy of hydrogen bonds between water molecules, in MPa 0.5 .

4. The binder treatment liquid according to claim 1, wherein The organic solvent is a single solvent.

5. The binder treatment liquid according to claim 1, wherein The organic solvent is a mixed solvent.

6. The binder treatment liquid according to claim 1, wherein The content ratio of the organic solvent when the total of the water and the organic solvent in the binder treatment liquid is 100% by weight is 1% by volume to 85% by volume.

7. The binder treatment liquid according to claim 1, wherein The adhesive is an adhesive contained in an adhesive tape.

8. A method for producing a recycled substrate, which is a method for producing a recycled substrate from an adhesive tape comprising a substrate and an adhesive, the method comprising the following impregnation step: The binder is impregnated with the binder treatment liquid according to any one of claims 1 to 7 to perform the impregnation treatment.

9. The method for producing a recycled substrate according to claim 8, wherein: In the impregnation step, the binder treatment liquid is subjected to at least one selected from the group consisting of stirring and ultrasonic irradiation.

10. The method for producing a recycled substrate according to claim 8, wherein: After the impregnation step, a raw material separation step of separating the structure derived from the substrate from the pressure-sensitive adhesive tape is included.

11. The method for producing a recycled substrate according to claim 10, wherein: In the raw material separation step, washing water is added to the pressure-sensitive adhesive tape after the impregnation treatment.

12. The method for producing a recycled substrate according to claim 11, wherein: Includes a liquid separation step to separate water and organic solvent.

13. A method for producing a recycled polymer composition, which is a method for producing a recycled polymer composition from an adhesive tape comprising a substrate and an adhesive, the method comprising the following impregnation step: The binder is impregnated with the binder treatment liquid according to any one of claims 1 to 7 to perform the impregnation treatment.

14. The method for producing a recycled polymer composition according to claim 13, wherein: In the impregnation step, the binder treatment liquid is subjected to at least one selected from the group consisting of stirring and ultrasonic irradiation.

15. The method for producing a recycled polymer composition according to claim 14, wherein: In the impregnation step, the binder treatment liquid is heated.

16. The method for producing a recycled polymer composition according to claim 13, wherein: After the impregnation step, a raw material separation step of separating the composition derived from the adhesive from the adhesive tape is included.

17. The method for producing a recycled polymer composition according to claim 16, wherein: In the raw material separation step, a cleaning liquid is added to the impregnation-treated pressure-sensitive adhesive tape.

18. The method for producing a recycled polymer composition according to claim 17, wherein: Includes a liquid separation step to separate water and organic solvent.

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