CN117580895A

CN117580895A - Method for producing water-soluble polymer, method for producing water-absorbent polymer, water-soluble polymer, and water-absorbent polymer

Info

Publication number: CN117580895A
Application number: CN202280046685.6A
Authority: CN
Inventors: 山田洋佑; 山本晃好; 野村隆之
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2021-06-30
Filing date: 2022-06-28
Publication date: 2024-02-20

Abstract

The present invention provides a method for producing a water-soluble polymer, which can produce a water-soluble polymer from a binder as waste under mild conditions, a method for producing a water-absorbent polymer, which can produce a water-absorbent polymer from a binder under mild conditions, a water-soluble polymer, which can be produced from a binder, and a water-absorbent polymer, which can be produced from a binder. The method for producing a water-soluble polymer according to an embodiment of the present invention brings a binder treatment liquid containing a liquid having a hansen solubility parameter value of 31 or less and an alkaline compound into contact with a binder, wherein the concentration of the alkaline compound in the binder treatment liquid is 0.001 to 20% by weight.

Description

Method for producing water-soluble polymer, method for producing water-absorbent polymer, water-soluble polymer, and water-absorbent polymer

Technical Field

The present invention relates to a method for producing a water-soluble polymer. The invention also relates to a method for producing the water-absorbent polymer. The invention also relates to water-soluble polymers. The invention also relates to water-absorbent polymers.

Background

As hydrophilic polymers having affinity for water, water-soluble polymers which are raw materials for various industrial products, water-absorbent polymers used in absorbent articles such as paper diapers, and the like are known. As a method for producing such a hydrophilic polymer, for example, a technique of producing a hydrophilic polymer by polymerizing a monomer by heating to about 175 ℃ in the presence of a catalyst has been reported (patent document 1).

However, in the technique described in patent document 1, it is necessary to select extremely high temperature conditions exceeding 150 ℃, and there is a limit in achieving an improvement in the production efficiency of the hydrophilic polymer.

In recent years, from the viewpoint of reducing environmental load, it has been desired to produce a polymer from waste. Particularly, in a hydrophilic polymer such as a water-soluble polymer and a water-absorbent polymer, which are widely used in industry, if the polymer can be regenerated from waste under mild conditions, the contribution to the reduction of environmental load is large. In this case, it can be said that it is very preferable if waste which can be produced in large amounts can be utilized.

Prior art literature

Patent literature

Patent document 1: japanese patent No. 3917178

Disclosure of Invention

Problems to be solved by the invention

In order to find out wastes which can be produced in a large amount under mild conditions and which can be produced in a large amount, hydrophilic polymers such as water-soluble polymers and water-absorbent polymers have been studied. As a result, attention is paid to the adhesive contained in the adhesive tape recovered after use, the adhesive in which the residual adhesive remains on the adherend when the adhesive tape is released from the adherend to which the adhesive tape is attached, the adhesive attached to the manufacturing apparatus of the adhesive, and the like as the adhesive of the waste. Then, the present invention has been completed by conducting intensive studies on a technique of regenerating a hydrophilic polymer such as a water-soluble polymer or a water-absorbent polymer from a binder which is such waste under mild conditions.

The present invention addresses the problem of providing a method for producing a water-soluble polymer, which can produce a water-soluble polymer from a binder under mild conditions, a method for producing a water-absorbent polymer, which can produce a water-absorbent polymer from a binder under mild conditions, a water-soluble polymer, which can produce a water-absorbent polymer from a binder, and a water-absorbent polymer, which can produce a water-absorbent polymer from a binder.

Solution for solving the problem

In the method for producing a water-soluble polymer according to the embodiment of the present invention,

And bringing the adhesive treatment liquid into contact with an adhesive, wherein the adhesive treatment liquid contains a liquid having a hansen solubility parameter value of 31 or less and an alkaline compound, and the concentration of the alkaline compound in the adhesive treatment liquid is 0.001 to 20 wt%.

In one embodiment, the hansen solubility parameter value of the liquid is 15 to 25 inclusive, and the liquid contains a lower alcohol.

In one embodiment, the adhesive is composed of an acrylic adhesive.

In one embodiment, the concentration of the alkaline compound in the treatment liquid is 0.01 to 10% by weight.

The water-soluble polymer according to the embodiment of the present invention is obtained by the method for producing a water-soluble polymer according to the embodiment of the present invention, and comprises a structural unit (1) represented by the following formula and a structural unit (2) represented by the following formula,

wherein R is ¹ Represents a hydrogen atom or a methyl group, R ² An alkyl group having 1 to 12 carbon atoms, and M represents a hydrogen atom or a cation.

In the method for producing a water-absorbent polymer according to the embodiment of the present invention, the water-soluble polymer obtained by the method for producing a water-soluble polymer according to the embodiment of the present invention is reacted with a crosslinking agent.

In the method for producing a water-absorbent polymer according to the embodiment of the present invention, a binder treatment liquid containing a liquid having a hansen solubility parameter value of 31 or less and an alkaline compound and a crosslinking agent are brought into contact with a binder, and the concentration of the alkaline compound in the binder treatment liquid is 0.001 to 20% by weight.

The water-absorbent polymer according to the embodiment of the present invention comprises a structural unit (1) represented by the following formula, a structural unit (2) represented by the following formula, and a crosslinked structure formed by reacting the structural unit (1) and/or the structural unit (2) with a crosslinking agent,

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a method for producing a water-soluble polymer, which can produce a water-soluble polymer from a binder under mild conditions, a method for producing a water-absorbent polymer, which can produce a water-absorbent polymer from a binder under mild conditions, a water-soluble polymer, which can produce a water-absorbent polymer from a binder, and a water-absorbent polymer, which can produce a water-absorbent polymer from a binder.

Detailed Description

In the present specification, when the expression "weight" is given, the expression "mass" which is commonly used as SI-based units indicating weight may be substituted.

In the present specification, the expression "acrylic acid" means "acrylic acid and/or methacrylic acid", the expression "acrylic acid ester and/or methacrylic acid ester", the expression "allyl (meth) group" means "allyl and/or methallyl", and the expression "acrolein and/or methacrolein".

Process for producing Water-soluble Polymer 1

In the method for producing a water-soluble polymer according to the embodiment of the present invention, the binder is brought into contact with the binder treatment liquid, whereby the water-soluble polymer is produced from the binder. According to the method for producing a water-soluble polymer of the embodiment of the present invention, various binders can be recycled, thereby producing a water-soluble polymer from the binder.

1-1 Adhesives

As the binder used as a raw material of the water-soluble polymer, any suitable binder may be used within a range that does not impair the effects of the present invention. As such an adhesive, typical examples of the adhesive to be used as waste include an adhesive contained in an adhesive tape recovered after use, an adhesive in which a residual adhesive remains on an adherend when the adhesive tape is peeled off from the adherend to which the adhesive tape is attached, and an adhesive attached to a manufacturing apparatus of the adhesive.

The pressure-sensitive adhesive tape typically includes an adhesive layer made of an adhesive and a substrate. The pressure-sensitive adhesive layer may be 1 layer or 2 or more layers.

Examples of the adherend include an adherend in which the function of the adherend may be reduced due to a small amount of residual glue, such as an electronic device such as a silicon wafer, a semiconductor circuit board, or a ceramic capacitor, an optical material such as an optical film or an optical glass.

Examples of the production apparatus of the adhesive include a polymerization reactor, a compounding apparatus, and a coater.

The pressure-sensitive adhesive is in the form of a pressure-sensitive adhesive layer contained in the pressure-sensitive adhesive tape, a pressure-sensitive adhesive in which a residual adhesive remains on an adherend, or a pressure-sensitive adhesive attached to a production apparatus such as a polymerization reactor, a compounding apparatus, or a coater, and therefore, the size and shape thereof are various. For example, if the pressure-sensitive adhesive layer is in the form of a pressure-sensitive adhesive layer contained in the pressure-sensitive adhesive tape, the thickness of the pressure-sensitive adhesive tape is preferably 1 μm to 2000 μm from the viewpoint of further exhibiting the effects of the present invention.

The adhesive is preferably composed of at least 1 selected from the group consisting of an acrylic adhesive, a urethane adhesive, a rubber adhesive, and a silicone adhesive, more preferably at least 1 selected from the group consisting of an acrylic adhesive, a urethane adhesive composition, and a silicone adhesive composition, and even more preferably an acrylic adhesive.

The adhesive may be formed by any suitable method. Examples of such methods include the following: the adhesive composition (at least 1 selected from the group consisting of an acrylic adhesive composition, a urethane adhesive composition, a rubber adhesive composition, and a silicone adhesive composition) is applied to any appropriate substrate, and if necessary, heated and dried to be cured, and an adhesive (specifically, an adhesive layer) is formed on the substrate. Examples of such coating methods include gravure roll coaters, reverse roll coaters, roll lick coaters, dip roll coaters, bar coaters, knife coaters, air knife coaters, spray coaters, comma coaters, direct coaters, roll brush coaters, and die coaters.

< acrylic adhesive >

The acrylic adhesive is formed from an acrylic adhesive composition.

From the viewpoint of further exhibiting the effects of the present invention, the acrylic adhesive composition preferably contains an acrylic polymer and a crosslinking agent.

The acrylic polymer is a polymer that may be referred to as a so-called base polymer in the field of acrylic adhesives. The number of acrylic polymers may be 1 or 2 or more.

The content of the acrylic polymer in the acrylic pressure-sensitive adhesive composition is preferably 50 to 100% by weight, more preferably 60 to 100% by weight, still more preferably 70 to 100% by weight, particularly preferably 80 to 100% by weight, and most preferably 90 to 100% by weight, as calculated by solid matter conversion.

Any suitable acrylic polymer may be used as the acrylic polymer within a range that does not impair the effects of the present invention.

From the viewpoint of further exhibiting the effects of the present invention, the weight average molecular weight of the acrylic polymer is preferably 100,000 ～ 3,000,000, more preferably 150,000 ～ 2,000,000, further preferably 200,000 ～ 1,500,000, and particularly preferably 250,000 ～ 1,000,000.

From the viewpoint of further exhibiting the effects of the present invention, the acrylic polymer is preferably an acrylic polymer formed by polymerizing a composition (a) containing at least 1 selected from the group consisting of (meth) acrylic esters having an alkyl group with an alkyl ester moiety of (a) and having from 4 to 12 carbon atoms, and (b) acrylic acid. The number of components (a) and (b) may be 1 or 2 or more, independently of each other.

Examples of the alkyl (meth) acrylate (component a) having 4 to 12 carbon atoms in the alkyl group of the alkyl ester moiety 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, dodecyl (meth) acrylate, and the like. Among them, n-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable, and n-butyl acrylate and 2-ethylhexyl acrylate are more preferable, from the viewpoint of further exhibiting the effects of the present invention.

Examples of at least 1 (component b) selected from the group consisting of (meth) acrylic acid esters having an OH group and (meth) acrylic acid include (meth) acrylic acid esters having an OH group such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and (meth) acrylic acid. Among them, from the viewpoint of further exhibiting the effects of the present invention, it is preferably hydroxyethyl (meth) acrylate, and (meth) acrylic acid, more preferably hydroxyethyl acrylate and acrylic acid.

The composition (a) may contain a copolymerizable monomer other than the (a) and (b) components. The number of copolymerizable monomers may be 1 or 2 or more. 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 anhydrides thereof (for example, anhydride group-containing monomers such as maleic anhydride and itaconic anhydride); amide group-containing monomers such as (meth) acrylamide, 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 t-butylaminoethyl (meth) acrylate; epoxy group-containing monomers such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate; cyano-containing monomers such as acrylonitrile and methacrylonitrile; heterocyclic ring-containing vinyl monomers such as N-vinyl-2-pyrrolidone, (meth) acryloylmorpholine, N-vinylpiperidone, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, vinylpyridine, and vinyloxazole; sulfonic acid group-containing monomers such as sodium vinylsulfonate; phosphate 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-methacryloxyethyl isocyanate; (meth) acrylic esters having an alicyclic hydrocarbon group such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, and isobornyl (meth) acrylate; phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate and other (meth) acrylates having an aromatic hydrocarbon group; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyl toluene; olefins such as ethylene, butadiene, isoprene and isobutylene, and dienes; vinyl ethers such as vinyl alkyl ether; vinyl chloride, and the like.

As the copolymerizable monomer, a polyfunctional monomer may be used. The polyfunctional monomer is a monomer having 2 or more ethylenically unsaturated groups in 1 molecule. As the ethylenically unsaturated group, any suitable ethylenically unsaturated group may be used within a range that does not impair the effects of the present invention. Examples of such an ethylenically unsaturated group include radically polymerizable functional groups such as vinyl, propenyl, isopropenyl, vinyl ether group (vinyloxy), and allyl ether group (allyloxy). Examples of the polyfunctional 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 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. The number of such polyfunctional monomers may be 1 or 2 or more.

As the copolymerizable monomer, 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 1 or 2 or more.

From the viewpoint of further exhibiting the effect of the present invention, the content of the alkyl (meth) acrylate (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% by weight to 100% by weight, still more preferably 70% by weight to 100% by weight, and particularly preferably 80% by weight to 100% by weight, relative to the total amount (100% by weight) of the monomer components constituting the acrylic polymer.

From the viewpoint of further exhibiting the effect of the present invention, the content of at least 1 (component b) selected from the group consisting of (meth) acrylic acid esters having OH groups and (meth) acrylic acid is preferably 0.1% by weight or more, more preferably 1.0% by weight to 50% by weight, still more preferably 1.5% by weight to 40% by weight, and particularly preferably 2.0% by weight to 30% by weight, relative to the total amount (100% by weight) of the monomer components constituting the acrylic polymer.

The acrylic polymer preferably contains 5 to 95 wt% of the sum of the above (a) component, the above (b) component, and the carboxyl group-containing monomer, more preferably 10 to 95 wt%, further preferably 15 to 95 wt%, further preferably 20 to 95 wt%, further preferably 25 to 95 wt%, further preferably 30 to 95 wt%, particularly preferably 35 to 90 wt%, and most preferably 40 to 90 wt%, with respect to the total amount of the monomer components (100 wt%).

The composition (a) may contain any appropriate other component within a range that does not impair the effects of the present invention. Examples of such other components include a polymerization initiator, a chain transfer agent, and a solvent. The content of these other components may be any suitable content within a range that does not impair the effects of the present invention.

The polymerization initiator may be a thermal polymerization initiator, a photopolymerization initiator (photoinitiator), or the like depending on the kind of polymerization reaction. The polymerization initiator may be 1 or 2 or more.

The thermal polymerization initiator may be preferably used in obtaining an acrylic polymer by solution polymerization. Examples of such a thermal polymerization initiator include azo-based polymerization initiators, peroxide-based polymerization initiators (e.g., dibenzoyl peroxide, t-butyl peroxymaleate, etc.), and redox-based polymerization initiators. Among these thermal polymerization initiators, azo-based initiators disclosed in JP-A2002-69411 are particularly preferable. Such azo-based polymerization initiator is preferable from the viewpoint of: the decomposition product of the polymerization initiator is less likely to remain in the acrylic polymer as a part that causes generation of a gas (outgas) by heating. Examples of the azo-based polymerization initiator include 2,2 '-azobisisobutyronitrile (hereinafter, sometimes referred to as AIBN), 2' -azobis-2-methylbutyronitrile (hereinafter, sometimes referred to as AMBN), dimethyl 2,2 '-azobis (2-methylpropionate), and 4,4' -azobis-4-cyanovaleric acid. The azo-based polymerization initiator is used in an amount of preferably 0.01 to 5.0 parts by weight, more preferably 0.05 to 4.0 parts by weight, still more 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, relative to the total amount (100 parts by weight) of the monomer components constituting the acrylic polymer.

The photopolymerization initiator may be preferably used when an acrylic polymer is obtained 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, benzil-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, and thioxanthone-based photopolymerization initiators.

Examples of the benzoin ether photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2-dimethoxy-1, 2-diphenylethane-1-one, anisole, and the like. Examples of the acetophenone photopolymerization initiator include 2, 2-diethoxyacetophenone, 2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, and 4- (t-butyl) dichloroacetophenone. Examples of the α -ketol photopolymerization initiator include 2-methyl-2-hydroxyphenylacetone and 1- [4- (2-hydroxyethyl) phenyl ] -2-methylpropan-1-one. Examples of the aromatic sulfonyl chloride-based photopolymerization initiator include 2-naphthalenesulfonyl chloride and the like. Examples of the photo-polymerization initiator for the photoactive oxime include 1-phenyl-1, 1-propanedione-2- (O-ethoxycarbonyl) -oxime. Examples of the benzoin photopolymerization initiator include benzoin. Examples of the benzil photopolymerization initiator include benzil. Examples of the benzophenone photopolymerization initiator include benzophenone, benzoyl benzoic acid, 3' -dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α -hydroxycyclohexyl phenyl ketone. Examples of the ketal photopolymerization initiator include benzildimethyl ketal and the like. Examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2, 4-dimethylthioxanthone, isopropylthioxanthone, 2, 4-diisopropylthioxanthone, and dodecylthioxanthone.

The amount of the photopolymerization initiator to be used is preferably 0.01 to 3.0 parts by weight, more preferably 0.015 to 2.0 parts by weight, still more 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, based on the total amount (100 parts by weight) of the monomer components constituting the acrylic polymer.

The acrylic adhesive composition may include a crosslinking agent. The effect of the present invention can be further exhibited by using a crosslinking agent to improve the cohesive force of the acrylic adhesive. The number of the crosslinking agents may be 1 or 2 or more.

Examples of the crosslinking agent include urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, and amine-based crosslinking agents, in addition to polyfunctional isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, and peroxide-based crosslinking agents. Among them, at least 1 (component c) selected from the group consisting of a polyfunctional isocyanate-based crosslinking agent and an epoxy-based crosslinking agent is preferable from the viewpoint of further exhibiting the effects of the present invention.

Examples of the polyfunctional isocyanate-based 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 cyclopentanediisocyanate, cyclohexyldiisocyanate, isophorone diisocyanate, hydrogenated toluene diisocyanate, and hydrogenated xylene diisocyanate; aromatic polyisocyanates such as 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate, 4' -diphenylmethane diisocyanate, and xylylene diisocyanate. Examples of the polyfunctional isocyanate-based crosslinking agent include trimethylolpropane/toluene diisocyanate adduct (trade name "cornonate L" manufactured by japan polyurethane industry co., ltd.), trimethylolpropane/hexamethylene diisocyanate adduct (trade name "cornonate HL" manufactured by japan polyurethane industry co., ltd.), trade name "cornonate HX" (japan polyurethane industry co., ltd.), and trimethylolpropane/xylylene diisocyanate adduct (trade name "take nate 110N" manufactured by Mitsui chemical co., ltd.).

Examples of the epoxy-based crosslinking agent (polyfunctional epoxy compound) include N, N' -tetraglycidyl m-xylylenediamine, diglycidyl aniline, 1, 3-bis (N, N-diglycidyl aminomethyl) 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, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having 2 or more epoxy groups in the molecule. As the epoxy-based crosslinking agent, commercially available products such as "TETRAD C" (manufactured by Mitsubishi gas chemical Co., ltd.) are also exemplified.

The content of the crosslinking agent in the acrylic adhesive composition may be any suitable content within a range that does not impair the effects of the present invention. From the viewpoint of further exhibiting the effects of the present invention, the content is preferably 0.1 to 5.0 parts by weight, more preferably 0.2 to 4.5 parts by weight, even more preferably 0.3 to 4.0 parts by weight, and particularly preferably 0.4 to 3.5 parts by weight, based on the solid content (100 parts by weight) of the acrylic polymer.

The acrylic adhesive composition may contain any appropriate other component within a range that does not impair the effects of the present invention. Examples of such other components include 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.), anti-aging agents, 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, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts, and the like.

< Silicone-based adhesive >

As the silicone-based adhesive, any suitable silicone-based adhesive such as a known silicone-based adhesive described in, for example, japanese patent application laid-open publication No. 2014-047280 can be used within a range that does not impair the effects of the present invention. These may be 1 kind or 2 or more kinds. The silicone-based adhesive may contain any suitable component within a range that does not impair the effects of the present invention.

< urethane-based adhesive >

The urethane adhesive is formed from a urethane adhesive composition.

From the viewpoint of further exhibiting the effects of the present invention, the urethane-based adhesive composition preferably contains at least 1 selected from the group consisting of urethane prepolymers and polyols and a crosslinking agent.

At least one selected from the group consisting of urethane prepolymers and polyols is a polymer which may be referred to as a so-called base polymer in the field of urethane-based adhesives. The urethane prepolymer may be 1 or 2 or more. The number of the polyhydric alcohols may be 1 or 2 or more.

[ urethane prepolymer ]

The urethane prepolymer is preferably a polyurethane polyol, and more preferably a polyester polyol (a 1) or a polyether polyol (a 2) is reacted with an organic polyisocyanate compound (a 3) alone or in the form of a mixture of (a 1) and (a 2) in the presence or absence of a catalyst.

As the polyester polyol (a 1), any suitable polyester polyol may be used. Examples of the polyester polyol (a 1) include a polyester polyol obtained by reacting an acid component with a glycol component. Examples of the acid component include terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, and trimellitic acid. Examples of the diol component include ethylene glycol, propylene glycol, diethylene glycol, butanediol, 1, 6-hexanediol, 3-methyl-1, 5-pentanediol, 3' -dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, 1, 4-butanediol, neopentyl glycol, and butylethylpentanediol, and examples of the polyol component include glycerol, trimethylolpropane, and pentaerythritol. Examples of the polyester polyol (a 1) include polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, poly (β -methyl- γ -valerolactone) and polycaprolactone.

As the molecular weight of the polyester polyol (a 1), low molecular weight to high molecular weight can be used. The molecular weight of the polyester polyol (a 1) is preferably 100 to 100000 in terms of further exhibiting the effect of the present invention. When the number average molecular weight is less than 100, reactivity becomes high, and gelation may be likely to occur. If the number average molecular weight exceeds 100000, the reactivity becomes low, and the cohesive force of the polyurethane polyol itself may be reduced. From the viewpoint of further exhibiting the effects of the present invention, the amount of the polyester polyol (a 1) used is preferably 0 to 90 mol% in the polyol constituting the polyurethane polyol.

As the polyether polyol (a 2), any suitable polyether polyol may be used. Examples of the polyether polyol (a 2) include polyether polyols obtained by polymerizing oxirane compounds such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran using a low molecular weight polyol such as water, propylene glycol, ethylene glycol, glycerin, and trimethylolpropane as an initiator. Specific examples of the polyether polyol (a 2) include polyether polyols having a functional group number of 2 or more, such as polypropylene glycol, polyethylene glycol, and polytetramethylene glycol.

As the molecular weight of the polyether polyol (a 2), low molecular weight to high molecular weight can be used. The polyether polyol (a 2) preferably has a number average molecular weight of 100 to 100000 from the viewpoint of further exhibiting the effect of the present invention. When the number average molecular weight is less than 100, reactivity becomes high, and gelation may be likely to occur. If the number average molecular weight exceeds 100000, the reactivity becomes low, and the cohesive force of the polyurethane polyol itself may be reduced. From the viewpoint of further exhibiting the effects of the present invention, the amount of the polyether polyol (a 2) used is preferably 0 to 90 mol% in the polyol constituting the polyurethane polyol.

The polyether polyol (a 2) may be used in combination by replacing a part thereof with a polyhydric amine such as ethylene glycol, 1, 4-butanediol, neopentyl glycol, butylethylpentanediol, glycerol, trimethylolpropane, pentaerythritol or the like, ethylenediamine, N-aminoethylethanolamine, isophoronediamine, xylylenediamine or the like, as necessary.

The polyether polyol (a 2) may be a polyether polyol having only 2 functions, or may be a polyether polyol having a number average molecular weight of 100 to 100000 and at least 3 or more hydroxyl groups in 1 molecule. When a polyether polyol having a number average molecular weight of 100 to 100000 and at least 3 or more hydroxyl groups in 1 molecule is partially or entirely used as the polyether polyol (a 2), the effect of the present invention can be further exhibited, and the balance between the adhesive force and the peelability can be improved. In such polyether polyols, when the number average molecular weight is less than 100, reactivity becomes high, and gelation may be likely to occur. In addition, when the number average molecular weight of such polyether polyol exceeds 100000, the reactivity becomes low, and the cohesive force of the polyurethane polyol itself may be reduced. From the viewpoint of further exhibiting the effects of the present invention, the number average molecular weight of such polyether polyol is more preferably 100 to 10000.

As the organic polyisocyanate compound (a 3), any suitable organic polyisocyanate compound may be used. Examples of the organic polyisocyanate compound (a 3) include aromatic polyisocyanates, aliphatic polyisocyanates, araliphatic polyisocyanates, and alicyclic polyisocyanates.

Examples of the aromatic polyisocyanate include 1, 3-phenylene diisocyanate, 4' -diphenyl diisocyanate, 1, 4-phenylene diisocyanate, 4' -diphenylmethane diisocyanate, 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate, 4' -toluidine diisocyanate, 2,4, 6-triisocyanate toluene, 1,3, 5-triisocyanate benzene, dianisidine diisocyanate, 4' -diphenyl ether diisocyanate, and 4,4',4 "-triphenylmethane triisocyanate.

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1, 2-propylene diisocyanate, 2, 3-butylene diisocyanate, 1, 3-butylene diisocyanate, dodecamethylene diisocyanate, and 2, 4-trimethylhexamethylene diisocyanate.

Examples of the aromatic aliphatic polyisocyanate include ω, ω '-diisocyanate-1, 3-dimethylbenzene, ω' -diisocyanate-1, 4-diethylbenzene, 1, 4-tetramethylxylylene diisocyanate, and 1, 3-tetramethylxylylene diisocyanate.

Examples of the alicyclic polyisocyanate include 3-isocyanatomethyl-3, 5-trimethylcyclohexyl isocyanate, 1, 3-cyclopentanediisocyanate, 1, 3-cyclohexanediisocyanate, 1, 4-cyclohexanediisocyanate, methyl-2, 6-cyclohexanediisocyanate, 4' -methylenebis (cyclohexylisocyanate), 1, 4-bis (isocyanatomethyl) cyclohexane, and 1, 4-bis (isocyanatomethyl) cyclohexane.

As the organic polyisocyanate compound (a 3), trimethylolpropane adducts, biurets obtained by reaction with water, and trimers having isocyanurate rings, etc. can be used in combination.

As the catalyst that can be used in obtaining the polyurethane polyol, any suitable catalyst can be used. Examples of such a catalyst include tertiary amine compounds and organometallic compounds.

Examples of the tertiary amine compound include triethylamine, triethylenediamine, and 1, 8-diazabicyclo (5, 4, 0) -undecene-7 (DBU).

Examples of the organometallic compound include tin compounds and non-tin compounds.

Examples of the tin-based compound include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin oxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate.

Examples of the non-tin compound include titanium compounds such as dibutyltitanium dichloride, tetrabutyl titanate, and butoxytitanium trichloride; lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate; iron-based compounds such as iron 2-ethylhexanoate and iron acetylacetonate; cobalt-based compounds such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc compounds such as zinc naphthenate and zinc 2-ethylhexanoate; zirconium compounds such as zirconium naphthenate.

When a catalyst is used for obtaining a polyurethane polyol, there is a problem that gelation or turbidity of a reaction solution is likely to occur in a single catalyst system due to the difference in reactivity among systems in which 2 polyols, namely a polyester polyol and a polyether polyol, are present. Therefore, by using 2 catalysts in obtaining the polyurethane polyol, the reaction rate, the selectivity of the catalyst, and the like become easy to control, and these problems can be solved. Examples of the combination of 2 catalysts include tertiary amine/organometallic system, tin system/non-tin system, and tin system/tin system, preferably tin system/tin system, and more preferably a combination of dibutyltin dilaurate and tin 2-ethylhexanoate. The compounding ratio of tin 2-ethylhexanoate/dibutyltin dilaurate is preferably less than 1, more preferably 0.2 to 0.6, in terms of weight ratio. When the compounding ratio is 1 or more, gelation may be easily caused by the balance of catalytic activity.

In the case of using the catalyst in obtaining the polyurethane polyol, the amount of the catalyst to be used is preferably 0.01 to 1.0% by weight relative to the total amount of the polyester polyol (a 1), the polyether polyol (a 2) and the organic polyisocyanate compound (a 3).

In the case of using a catalyst in obtaining the polyurethane polyol, the reaction temperature is preferably less than 100 ℃, more preferably 85 ℃ to 95 ℃. If it reaches 100℃or higher, it may become difficult to control the reaction rate, the crosslinked structure, and it may become difficult to obtain a polyurethane polyol having a prescribed molecular weight.

In obtaining the polyurethane polyol, a catalyst may not be used. In this case, the reaction temperature is preferably 100℃or higher, more preferably 110℃or higher. In addition, when the polyurethane polyol is obtained without a catalyst, the reaction is preferably carried out for 3 hours or more.

Examples of the method for obtaining the polyurethane polyol include 1) a method in which all of the polyester polyol, polyether polyol, catalyst and organic polyisocyanate are charged into a flask, and 2) a method in which the polyester polyol, polyether polyol and catalyst are charged into a flask and the organic polyisocyanate is added. As a method for obtaining the polyurethane polyol, the method of 2) is preferable in terms of controlling the reaction.

In obtaining the polyurethane polyol, any suitable solvent may be used. Examples of such solvents include methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone. Among these solvents, toluene is preferred.

[ polyol ]

Examples of the polyol include polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol and castor oil polyol. The polyol is more preferably a polyether polyol.

The polyester polyol can be obtained, for example, by esterification reaction of a polyol component with an acid component.

Examples of the polyhydric alcohol component include ethylene glycol, diethylene glycol, 1, 3-butanediol, 1, 4-butanediol, neopentyl glycol, 3-methyl-1, 5-pentanediol, 2-butyl-2-ethyl-1, 3-propanediol, 2, 4-diethyl-1, 5-pentanediol, 1, 2-hexanediol, 1, 6-hexanediol, 1, 8-octanediol, 1, 9-nonanediol, 2-methyl-1, 8-octanediol, 1, 8-decanediol, octadecanediol, glycerol, trimethylolpropane, pentaerythritol, hexanetriol, and polypropylene glycol. Examples of the acid component include succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1, 12-dodecanedioic acid, 1, 14-tetradecanedioic acid, dimer acid, 2-methyl-1, 4-cyclohexanedicarboxylic acid, 2-ethyl-1, 4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1, 4-naphthalenedicarboxylic acid, 4' -biphenyldicarboxylic acid, and anhydrides thereof.

Examples of the polyether polyol include polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide using water, a low molecular polyol (propylene glycol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, and the like), bisphenols (bisphenol a, and the like), dihydroxybenzenes (catechol, resorcinol, hydroquinone, and the like), and the like as an initiator. Specifically, polyethylene glycol, polypropylene glycol and polytetramethylene glycol are exemplified.

Examples of the polycaprolactone polyols include caprolactone-based polyester diols obtained by ring-opening polymerization of cyclic ester monomers such as epsilon-caprolactone and sigma-valerolactone.

Examples of the polycarbonate polyol include a polycarbonate polyol obtained by polycondensation of the above polyol component with phosgene; polycarbonate polyols obtained by transesterification condensation of the above polyol component with a carbonic acid diester such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethylbutyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate, dibenzyl carbonate, etc.; a copolymerized polycarbonate polyol obtained by using 2 or more of the above polyol components in combination; a polycarbonate polyol obtained by subjecting the above-mentioned various polycarbonate polyols to an esterification reaction with a carboxyl group-containing compound; a polycarbonate polyol obtained by subjecting the above-mentioned various polycarbonate polyols to etherification reaction with a hydroxyl group-containing compound; a polycarbonate polyol obtained by transesterification of the various polycarbonate polyols with an ester compound; a polycarbonate polyol obtained by subjecting the above-mentioned various polycarbonate polyols to transesterification with a hydroxyl group-containing compound; a polyester-based polycarbonate polyol obtained by polycondensation of the various polycarbonate polyols and a dicarboxylic acid compound; and copolyether-based polycarbonate polyols obtained by copolymerizing the above-mentioned various polycarbonate polyols with an alkylene oxide.

Examples of the castor oil-based polyol include castor oil-based polyols obtained by reacting castor oil fatty acids with the above-mentioned polyol component. Specifically, for example, castor oil polyols obtained by reacting castor oil fatty acids with polypropylene glycol are mentioned.

From the viewpoint of further exhibiting the effects of the present invention, the number average molecular weight Mn of the polyol is preferably 300 to 100000, more preferably 400 to 75000, further preferably 450 to 50000, and particularly preferably 500 to 30000.

From the viewpoint of further exhibiting the effects of the present invention, the polyol (A1) having 3 OH groups and having a number average molecular weight Mn of 300 to 100000 is preferably contained. The polyol (A1) may be one kind only or 2 or more kinds.

From the viewpoint of further exhibiting the effects of the present invention, the content of the polyol (A1) in the polyol is preferably 5% by weight or more, more preferably 25% by weight to 100% by weight, and still more preferably 50% by weight to 100% by weight.

From the viewpoint of further exhibiting the effects of the present invention, the number average molecular weight Mn of the polyol (A1) is preferably 1000 to 100000, more preferably more than 1000 and not more than 80000, further preferably 1100 to 70000, further preferably 1200 to 60000, further preferably 1300 to 50000, further preferably 1400 to 40000, further preferably 1500 to 35000, particularly preferably 1700 to 32000, and most preferably 2000 to 30000.

The polyol may contain a polyol (A2) having 3 or more OH groups and a number average molecular weight Mn of 20000 or less. The number of the polyols (A2) may be 1 or 2 or more. From the viewpoint of further exhibiting the effects of the present invention, the number average molecular weight Mn of the polyol (A2) is preferably 100 to 20000, more preferably 150 to 10000, further preferably 200 to 7500, particularly preferably 300 to 6000, and most preferably 300 to 5000. From the viewpoint of further exhibiting the effect of the present invention, the polyol (A2) is preferably a polyol (triol) having 3 OH groups, a polyol (tetraol) having 4 OH groups, a polyol (pentaol) having 5 OH groups, or a polyol (hexaol) having 6 OH groups.

From the viewpoint of further exhibiting the effect of the present invention, the content ratio of the total amount of the polyol having 4 OH groups (tetraol), the polyol having 5 OH groups (pentaol), and the polyol having 6 OH groups (hexaol) in the polyol (A2) is preferably 70 wt% or less, more preferably 60 wt% or less, still more preferably 40 wt% or less, and particularly preferably 30 wt% or less.

From the viewpoint of further exhibiting the effect of the present invention, the content of the polyol (A2) in the polyol is preferably 95% by weight or less, more preferably 0% by weight to 75% by weight.

From the viewpoint of further exhibiting the effect of the present invention, the content of the polyol having 4 or more OH groups and having a number average molecular weight Mn of 20000 or less as the polyol (A2) is preferably less than 70 wt%, more preferably 60 wt% or less, still more preferably 50 wt% or less, particularly preferably 40 wt% or less, and most preferably 30 wt% or less, relative to the entire polyol.

[ Cross-linking agent ]

From the viewpoint of further exhibiting the effects of the present invention, the urethane-based adhesive composition preferably contains a crosslinking agent.

The urethane prepolymer and the polyol as the base polymer may be combined with a crosslinking agent, respectively, to be components of the urethane adhesive composition.

The crosslinking agent to be combined with the urethane prepolymer and the polyol as the base polymer is preferably a polyfunctional isocyanate-based crosslinking agent from the viewpoint of further exhibiting the effect of the present invention.

As the polyfunctional isocyanate-based crosslinking agent, any suitable polyfunctional isocyanate-based crosslinking agent that can be used for the urethanization reaction can be used. Examples of such a polyfunctional isocyanate-based crosslinking agent include the polyfunctional isocyanate-based crosslinking agent described in < acrylic pressure-sensitive adhesive > above.

[ urethane adhesive composition ]

The urethane adhesive composition may contain any appropriate other component within a range that does not impair the effects of the present invention. Examples of such other components include urethane prepolymers and polymer components other than polyols, crosslinking accelerators, crosslinking catalysts, silane coupling agents, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), anti-aging agents, inorganic fillers, organic fillers, metal powders, colorants (pigments, dyes, etc.), foils, anti-deterioration agents, chain transfer agents, plasticizers, softeners, surfactants, antistatic agents, conductive agents, stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts, and the like.

From the viewpoint of further exhibiting the effects of the present invention, the urethane-based adhesive composition preferably contains an anti-deterioration agent. The number of the deterioration preventing agents may be 1 or 2 or more.

From the viewpoint of further exhibiting the effects of the present invention, antioxidants, ultraviolet absorbers, and light stabilizers are preferable as the deterioration preventing agents.

Examples of the antioxidant include a radical chain inhibitor and a peroxide decomposer.

Examples of the radical chain inhibitor include phenol antioxidants and amine antioxidants.

Examples of the phenolic antioxidants include monophenol antioxidants, bisphenol antioxidants, and polymeric phenolic antioxidants. Examples of the monophenol antioxidant include 2, 6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2, 6-di-t-butyl-4-ethylphenol, and stearyl- β - (3, 5-di-t-butyl-4-hydroxyphenyl) propionate. Examples of bisphenol antioxidants include 2,2 '-methylenebis (4-methyl-6-t-butylphenol), 2' -methylenebis (4-ethyl-6-t-butylphenol), 4 '-thiobis (3-methyl-6-t-butylphenol), 4' -butylidenebis (3-methyl-6-t-butylphenol), and 3, 9-bis [1, 1-dimethyl-2- [ β - (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy ] ethyl ]2,4,8, 10-tetraoxaspiro [5,5] undecane. Examples of the polymer type phenol antioxidant include 1, 3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3, 5-trimethyl-2, 4, 6-tris (3, 5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [ methylene-3- (3 ',5' -di-t-butyl-4 ' -hydroxyphenyl) propionate ] methane, bis [3,3' -bis- (4 ' -hydroxy-3 ' -t-butylphenyl) butanoic acid ] ethylene glycol ester, 1,3, 5-tris (3 ',5' -di-t-butyl-4 ' -hydroxybenzyl) -S-triazine-2, 4,6- (1H, 3H, 5H) trione, tocopherol, and the like.

Examples of the peroxide decomposer include a sulfur-based antioxidant and a phosphorus-based antioxidant. Examples of the sulfur-based antioxidant include dilauryl 3,3' -thiodipropionate, dimyristyl 3,3' -thiodipropionate, distearyl 3,3' -thiodipropionate, and the like. Examples of the phosphorus antioxidant include triphenyl phosphite, diphenyl isodecyl phosphite, and phenyl diisodecyl phosphite.

Examples of the ultraviolet absorber include benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, salicylic acid-based ultraviolet absorbers, oxanilide-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, and triazine-based ultraviolet absorbers.

Examples of the benzophenone-based ultraviolet light absorber include 2, 4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2' -dihydroxy-4-dimethoxybenzophenone, 2' -dihydroxy-4, 4' -dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, and bis (2-methoxy-4-hydroxy-5-benzoylphenyl) methane.

Examples of the benzotriazole-based ultraviolet light absorber include 2- (2 ' -hydroxy-5 ' -methylphenyl) benzotriazole, 2- (2 ' -hydroxy-5 ' -tert-butylphenyl) benzotriazole, 2- (2 ' -hydroxy-3 ',5' -di-tert-butylphenyl) benzotriazole, 2- (2 ' -hydroxy-3 ' -tert-butyl-5 ' -methylphenyl) -5-chlorobenzotriazole, 2- (2 ' -hydroxy-3 ',5' -di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2 ' -hydroxy-3 ',5' -di-tert-pentylphenyl) benzotriazole, 2- (2 ' -hydroxy-4 ' -octyloxyphenyl) benzotriazole, 2- [2' -hydroxy-3 ' - (3 ",4",5",6 ', -tetrahydrophthalimidomethyl) -5' -methylphenyl ] benzotriazole, 2' -methylenebis [4- (1, 3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol ], 2- (2 ' -hydroxy-5 ' -methacryloxyphenyl) -2H-benzotriazol and the like.

Examples of the salicylic acid ultraviolet absorber include phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate.

Examples of the cyanoacrylate-based ultraviolet absorber include 2-ethylhexyl-2-cyano-3, 3 '-diphenylacrylate and ethyl-2-cyano-3, 3' -diphenylacrylate.

Examples of the light stabilizer include hindered amine light stabilizers and ultraviolet light stabilizers. As the hindered amine-based light stabilizer, examples thereof include bis (2, 6-tetramethyl-4-piperidinyl) sebacate bis (1, 2, 6-pentamethyl-4-piperidinyl) sebacate, methyl-1, 2, 6-pentamethyl-4-piperidinyl sebacate, and the like. Examples of the ultraviolet stabilizer include nickel bis (octylphenyl) sulfide, nickel [2,2' -thiobis (4-t-octylphenol) ] -n-butylamine, nickel complex-monoethyl 3, 5-di-t-butyl-4-hydroxybenzyl-phosphate, benzoate-type quenchers, nickel-dibutyldithiocarbamate, and the like.

[ urethane polymer formed from urethane adhesive composition comprising urethane prepolymer and polyfunctional isocyanate-based crosslinking agent ]

The urethane prepolymer may be 1 or 2 or more. The number of the polyfunctional isocyanate-based crosslinking agents may be 1 or 2 or more.

Any suitable method may be used as long as the method for producing the urethane polymer from the urethane adhesive composition containing the urethane prepolymer and the polyfunctional isocyanate-based crosslinking agent is a method for producing the urethane polymer using the so-called "urethane prepolymer" as a raw material.

From the viewpoint of further exhibiting the effect of the present invention, the number average molecular weight Mn of the urethane prepolymer is preferably 3000 to 1000000.

The equivalent ratio of NCO groups to OH groups in the urethane prepolymer and the polyfunctional isocyanate-based crosslinking agent is preferably 5.0 or less, more preferably 0.01 to 4.75, still more preferably 0.02 to 4.5, particularly preferably 0.03 to 4.25, and most preferably 0.05 to 4.0 in terms of NCO groups/OH groups, from the viewpoint that the effect of the present invention can be further exhibited.

The content of the polyfunctional isocyanate-based crosslinking agent is preferably 0.01 to 30 parts by weight, more preferably 0.05 to 25 parts by weight, still more preferably 0.1 to 20 parts by weight, particularly preferably 0.5 to 17.5 parts by weight, and most preferably 1 to 15 parts by weight, based on 100 parts by weight of the urethane prepolymer, from the viewpoint of further exhibiting the effect of the present invention.

[ urethane polymer comprising urethane adhesive composition comprising polyol and polyfunctional isocyanate-based crosslinking agent ]

The number of polyols may be only 1. It may be 2 or more. The number of the polyfunctional isocyanate-based crosslinking agents may be only 1. It may be 2 or more.

The equivalent ratio of NCO groups to OH groups in the polyol and the polyfunctional isocyanate-based crosslinking agent is preferably 5.0 or less, more preferably 0.1 to 3.0, still more preferably 0.2 to 2.5, particularly preferably 0.3 to 2.25, and most preferably 0.5 to 2.0 in terms of NCO groups/OH groups, from the viewpoint that the effect of the present invention can be further exhibited.

The content of the polyfunctional isocyanate-based crosslinking agent is preferably 1.0 to 30 parts by weight, more preferably 1.5 to 27 parts by weight, still more preferably 2.0 to 25 parts by weight, particularly preferably 2.3 to 23 parts by weight, and most preferably 2.5 to 20 parts by weight, based on 100 parts by weight of the polyol, from the viewpoint of further exhibiting the effect of the present invention.

The urethane polymer formed from the urethane adhesive composition containing a polyol and a polyfunctional isocyanate-based crosslinking agent is preferably formed by curing the urethane adhesive composition containing a polyol and a polyfunctional isocyanate-based crosslinking agent. As a method for forming a urethane polymer by curing a urethane adhesive composition containing a polyol and a polyfunctional isocyanate-based crosslinking agent, any suitable method such as a urethanization reaction method using bulk polymerization, solution polymerization or the like can be employed within a range that does not impair the effects of the present invention.

In order to cure the urethane-based adhesive composition containing the polyol and the polyfunctional isocyanate-based crosslinking agent, a catalyst is preferably used. Examples of such a catalyst include an organometallic compound and a tertiary amine compound.

Examples of the organometallic compound include iron-based compounds, tin-based compounds, titanium-based compounds, zirconium-based compounds, lead-based compounds, cobalt-based compounds, and zinc-based compounds. Among them, iron-based compounds and tin-based compounds are preferable from the viewpoints of reaction rate and pot life of the adhesive layer.

Examples of the iron-based compound include iron acetylacetonate, iron 2-ethylhexanoate, and iron acetylacetonate.

Examples of the tin-based compound include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin maleate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin sulfide, tributyltin methoxide, tributyltin acetate, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, dioctyltin dilaurate, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate.

Examples of the titanium compound include dibutyl titanium dichloride, tetrabutyl titanate, and butoxytitanium trichloride.

Examples of the zirconium-based compound include zirconium naphthenate and zirconium acetylacetonate

Examples of the lead compound include lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate.

Examples of the cobalt-based compound include cobalt 2-ethylhexanoate, cobalt benzoate, and the like.

Examples of the zinc compound include zinc naphthenate and zinc 2-ethylhexanoate.

Examples of the tertiary amine compound include triethylamine, triethylenediamine, and 1, 8-diazabicyclo- (5, 4, 0) -undecene-7.

The number of the catalysts may be 1 or 2 or more. In addition, a catalyst, a crosslinking retarder, and the like may be used in combination. From the viewpoint of further exhibiting the effect of the present invention, the amount of the catalyst is preferably 0.005 to 1.00 parts by weight, more preferably 0.01 to 0.75 parts by weight, still more preferably 0.01 to 0.50 parts by weight, and particularly preferably 0.01 to 0.20 parts by weight, based on 100 parts by weight of the polyol.

1-2 adhesive treatment liquid

The adhesive treatment liquid used in the embodiment of the present invention contains a liquid having a hansen solubility parameter value of 31 or less and an alkaline compound, and the concentration of the alkaline compound is 0.001 to 20 wt%.

The term "liquid" as used herein refers to a substance that is liquid at normal temperature and pressure, and generally includes water, alcohols, and other various solvents.

The hansen solubility parameter value of the binder treatment liquid may be 1 or 2 or more.

The alkali compound in the pressure-sensitive adhesive treatment liquid may be 1 or 2 or more.

The adhesive treatment liquid contains a liquid having a hansen solubility parameter value of 31 or less and an alkaline compound, and the concentration of the alkaline compound is 0.01 to 10 wt%, whereby a water-soluble polymer can be smoothly produced from the adhesive under mild conditions.

The "hansen solubility parameter value" is obtained by dividing Hildebrand (Hildebrand) solubility parameter values into discrete terms (δ) _D ) Polar term (delta) _p ) Hydrogen bond term (delta) _H ) These 3 components are sometimes referred to simply as HSP values, taking into account the parameter values of the polarity of the substance. Dispersion terms (terms related to van der waals forces), polar terms (terms related to dipole moment), and hydrogen bonding terms (terms related to hydrogen bonding)May be represented in three-dimensional coordinates.

The hansen solubility parameter value of a mixed solution of 2 or more liquids can be obtained as a weighted average value m of HSP values of the respective solvents by the following formula (1). Delta 1 and delta 2 are HSP values of the respective liquid components, And->The volume fraction of each liquid component.

The hansen solubility parameter values for each solvent are recorded in "hspin version 5", and as for the solvents not recorded, values estimated by "hspin version 5" are used.

The hansen solubility parameter value of the liquid contained in the binder treatment liquid is 31 or less, preferably 30 or less, more preferably 29 or less, further preferably 28 or less, and particularly preferably 25 or less. The lower limit value of the hansen solubility parameter value of the liquid contained in the binder treatment liquid is preferably 7 or more, more preferably 10 or more, still more preferably 13 or more, and particularly preferably 15 or more. When the hansen solubility parameter value of the liquid contained in the binder treatment liquid is within the above range, preferably 10 to 30, more preferably 15 to 25, the water-soluble polymer can be stably produced from the binder under mild conditions.

When the hansen solubility parameter value of the liquid contained in the adhesive treatment liquid exceeds 31, the permeability of the adhesive treatment liquid to the adhesive may be deteriorated, and the production efficiency of the water-soluble polymer may be lowered. In addition, when the hansen solubility parameter value of the liquid contained in the adhesive treatment liquid is less than 7, there is a concern that the permeability of the adhesive treatment liquid to the adhesive may be deteriorated, and the production efficiency of the water-soluble polymer may be lowered, as in the case of exceeding 31.

The following liquids are typically used as the liquid having a hansen solubility parameter value of 31 or less as a single liquid contained in the binder treatment liquid.

Alcohols; methanol (hsp=29.6), ethanol (hsp=26.5), 1-propanol (hsp=24.6), 2-propanol (IPA) (hsp=23.6), 1-butanol (hsp=23.2), 1-pentanol (hsp=21.7), 1-hexanol (hsp=21.2), benzyl alcohol (hsp=23.8), diethylene glycol (hsp=27.9), dipropylene glycol (sp=26.4)

Hydrocarbons; benzene (hsp=18.5), toluene (hsp=18.2), styrene (hsp=19.1), hexane (hsp=14.9), cyclohexane (hsp=16.8), heptane (hsp=15.3)

Ketones; acetone (hsp=19.9), methyl ethyl ketone (hsp=19.1)

Esters; ethyl acetate (HSP value=18.2)

Ethers; tetrahydrofuran (hsp=19.5), cyclopentyl methyl ether (hsp=17.8)

Amines; aniline (HSP value=23.7)

Nitriles; acetonitrile (HSP value=24.4)

Carboxylic acids; acetic acid (HSP value=21.4)

Terpenes; d-limonene (HSP value=17.8)

These liquids may be used in an amount of 1 or 2 or more. In addition to a liquid having a hansen solubility parameter value of 31 or less as a single liquid, a mixed liquid having m of 31 or less based on the above formula (1) may be used as long as the hansen solubility parameter value is calculated as a mixed liquid obtained by combining a plurality of liquids. As a solvent which can be used as a mixed solution by combining a plurality of liquids, for example, water (HSP value=47.8) is mentioned. For example, when water (HSP value=47.8) and ethanol (HSP value=26.5) are calculated as water/ethanol=20%/80% by volume fraction, m=30.76 can be used.

From the viewpoint of solubility of the basic compound, the liquid having a hansen solubility parameter value of 31 or less preferably contains an alcohol, more preferably contains a lower alcohol. The lower alcohol may include not only a primary alcohol but also a secondary alcohol such as 2-propanol, propylene glycol monopropyl ether, propylene glycol monoethyl ether, and a tertiary alcohol such as tertiary butanol.

The lower alcohol is preferably a lower alcohol having 1 to 5 carbon atoms (typically at least 1 selected from methanol, ethanol, 1-propanol, 2-propanol, butanol, and 1-pentanol), more preferably a lower alcohol having 1 to 4 carbon atoms (typically at least 1 selected from methanol, ethanol, 1-propanol, 2-propanol, and butanol), still more preferably a lower alcohol having 1 to 3 carbon atoms (typically at least 1 selected from methanol, ethanol, 1-propanol, and 2-propanol), and particularly preferably a lower alcohol having 1 to 2 carbon atoms (at least 1 selected from methanol and ethanol).

The liquid having a hansen solubility parameter value of 31 or less preferably contains an organic solvent other than alcohols in addition to alcohols. The organic solvents other than alcohols may be used in an amount of 1 or 2 or more. The organic solvent other than alcohols is, for example, the above ethers or the above hydrocarbons, preferably at least 1 selected from toluene, cyclopentylmethyl ether and tetrahydrofuran, and more preferably at least 1 selected from toluene and cyclopentylmethyl ether. When the liquid having a hansen solubility parameter value of 31 or less is a mixed solvent of an alcohol and an organic solvent (preferably at least 1 selected from ethers and hydrocarbons), the permeability of the adhesive treatment liquid to the adhesive can be improved, and the production efficiency of the water-soluble polymer can be improved.

When the liquid having a hansen solubility parameter value of 31 or less contains an alcohol or an organic solvent other than an alcohol (preferably at least 1 selected from ethers and hydrocarbons), the volume ratio of the organic solvent to the alcohol (organic solvent: alcohol) is preferably 10: 90-99: 1. more preferably 20: 80-95: 5. further preferably 30: 70-90: 10. particularly preferred is 40: 60-90: 10. most preferably 60: 40-80: 20. when the volume ratio of the organic solvent to the alcohol is in the above range, the permeability of the adhesive treatment liquid to the adhesive can be further improved, and the production efficiency of the water-soluble polymer can be stably improved.

The basic compound contained in the adhesive treatment liquid may be any suitable basic compound within a range that does not impair the effect of the present invention. Examples of such basic compounds include hydroxides and carbonates of alkali metals and alkaline earth metals such as potassium hydroxide, sodium hydroxide and calcium hydroxide; the metal alkoxide such as sodium methoxide, sodium ethoxide, and potassium tert-butoxide is preferably at least 1 selected from the group consisting of potassium hydroxide, sodium hydroxide, and sodium ethoxide.

The concentration of the alkaline compound in the adhesive treatment liquid is preferably 0.001 to 20 wt%, more preferably 0.01 to 10 wt%, still more preferably 0.01 to 8 wt%, particularly preferably 0.01 to 5 wt%, and most preferably 0.5 to 1.5 wt%. When the concentration of the basic compound in the adhesive treatment liquid is within the above range, a water-soluble polymer can be produced from the adhesive more stably under mild conditions. When the concentration of the alkali compound in the pressure-sensitive adhesive treatment liquid exceeds 20% by weight, the alkali compound is less likely to be dissolved in the treatment solvent (liquid having a hansen solubility parameter value of 31 or less), and in the case of the pressure-sensitive adhesive tape, not only the pressure-sensitive adhesive but also the base material may be adversely affected.

Other additives may be included in the adhesive treatment fluid. As other additives, any suitable additives may be used within a range that does not impair the effects of the present invention. Examples of such additives include various known additives such as ionic surfactants, nonionic surfactants, chelating agents, solubilizing agents, sizing agents, and defoaming agents.

1-3 adhesive treatment Process

In the method for producing a water-soluble polymer according to the embodiment of the present invention, the adhesive agent is typically impregnated with the adhesive agent treatment liquid. Thus, the water-soluble polymer can be smoothly produced from the binder under mild conditions.

As a method for impregnating the adhesive with the adhesive treatment liquid, any suitable impregnation method may be suitably used depending on the scale and the type of adhesive. In the present specification, "impregnating the adhesive agent with the adhesive agent treatment liquid" refers to a state in which the adhesive agent treatment liquid is impregnated with the adhesive agent, and examples thereof include a state in which at least a part of the adhesive agent is immersed in the adhesive agent treatment liquid. This is because, if at least a part of the adhesive is immersed in the adhesive treatment liquid, the adhesive treatment liquid gradually impregnates the adhesive.

In the method for producing a water-soluble polymer according to the embodiment of the present invention, a preferable embodiment is to stir the adhesive treatment liquid in a state of being impregnated with the adhesive. By stirring the adhesive treatment liquid in a state of being impregnated with the adhesive, the water-soluble polymer can be produced from the adhesive more smoothly. In the present specification, the term "a state in which the adhesive treatment liquid is impregnated with the adhesive" refers to a state in which the adhesive treatment liquid is impregnated with the adhesive, and examples thereof include a state in which at least a part of the adhesive is immersed in the adhesive treatment liquid. This is because, if at least a part of the adhesive is immersed in the adhesive treatment liquid, the adhesive treatment liquid gradually impregnates the adhesive.

As a method of stirring, any suitable stirring method may be suitably employed depending on the scale and the kind of binder.

In the adhesive treatment method according to the embodiment of the present invention, it is preferable that the ultrasonic treatment is performed in a state where the adhesive treatment liquid is impregnated with the adhesive. By performing ultrasonic treatment in a state where the adhesive agent treatment liquid is impregnated with the adhesive agent, a water-soluble polymer can be produced more smoothly from the adhesive agent.

As the ultrasonic treatment method, any suitable ultrasonic treatment method may be suitably used depending on the scale and the kind of the adhesive.

In the method for producing a water-soluble polymer according to the embodiment of the present invention, in a preferred embodiment, the temperature at which the binder treatment liquid is impregnated with the binder is preferably 20 ℃ or higher, more preferably 25 ℃ or higher, further preferably 30 ℃ or higher, further preferably 35 ℃ or higher, further preferably 40 ℃ or higher, particularly preferably 45 ℃ or higher, and the upper limit is preferably 120 ℃ or lower, more preferably 100 ℃ or lower, further preferably 80 ℃ or lower. When the temperature at which the binder treatment liquid is impregnated with the binder is within the above range, the water-soluble polymer can be easily and smoothly produced from the binder under mild conditions.

In the method for producing a water-soluble polymer according to an embodiment of the present invention, another preferred embodiment produces a water-soluble polymer from an adhesive of an adhesive tape including a base material and an adhesive. In more detail, first, as a method of separating the adhesive tape into the substrate and the adhesive, a physical method may be applied. Specifically, the adhesive is peeled from the adhesive tape using a polishing cloth, a polishing tape, a polishing paper, a polishing brush, or the like, and separated into a base material and an adhesive. The separated adhesive is impregnated with the adhesive treatment liquid.

It is presumed that, according to the method for producing a water-soluble polymer of the embodiment of the present invention, the binder swells by the binder treatment liquid, and hydrolysis (including saponification reaction of the salt and alcohol by reaction of the ester with the base) is performed by the liquid having a hansen solubility parameter value of 31 or less and the basic compound contained in the binder treatment liquid, and the like. By reacting around the saponification reaction, a water-soluble polymer can be efficiently produced. Since the activation energy required for saponification is higher than that of the transesterification reaction, the reaction can be appropriately controlled by, for example, conducting the reaction at a temperature in the above-mentioned range (preferably 20℃to 120 ℃). Thus, the water-soluble polymer is formed from the binder and dissolved or dispersed in the binder treatment liquid according to the embodiment of the present invention. Such a water-soluble polymer derived from the binder can be recovered as a solution or dispersion by further treating with a solvent as necessary, and as a preferred embodiment, the water-soluble polymer can be recovered as a solution in which the water-soluble polymer is dissolved in an aqueous solvent. Examples of the aqueous solvent include water, alcohols, mixed solvents thereof, and mixed solvents of these solvents and organic solvents. Here, the "water-soluble polymer derived from the binder" refers to a water-soluble polymer having a structure derived from a main polymer (also referred to as a base polymer) used in the constitution of the binder, and specifically, for example, refers to a water-soluble polymer having the following structure: at least a part of functional groups (for example, carboxyl groups and ester groups) present at the terminal ends of the side chains of the main polymer (sometimes referred to as a base polymer) constituting the adhesive is hydrolyzed by a liquid having a hansen solubility parameter value of 31 or less contained in the adhesive treatment liquid and an alkaline compound (including saponification reaction of an alcohol with a salt formed by reaction of an ester with a base).

According to the method for producing a water-soluble polymer of the embodiment of the present invention, the water-soluble polymer can be easily obtained from the binder under mild conditions. This is presumed to be because: according to the method for producing a water-soluble polymer of the embodiment of the present invention, hydrolysis of the binder (including saponification of the salt and alcohol by reaction of the ester with the base) is simply performed under mild conditions, and as a result, a water-soluble polymer can be obtained.

Conventionally, in order to hydrolyze an adhesive (including saponification of an ester with a base to form a salt and an alcohol), it has been necessary to perform the above reaction on the adhesive under high temperature and high pressure, or to design the composition of the adhesive to a limited composition. According to the method for producing a water-soluble polymer of the embodiment of the present invention, excellent hydrolysis of the binder (including saponification of the salt and alcohol by reaction of the ester with the base) can be easily performed under mild conditions without requiring conditions of high temperature and high pressure, and without requiring the composition of the binder to be designed to a limited composition.

2 Water-soluble Polymer

The water-soluble polymer obtained by the method for producing a water-soluble polymer according to the embodiment of the present invention typically comprises a structural unit (1) represented by the following formula and a structural unit (2) represented by the following formula,

The water-soluble polymer typically contains a plurality of structural units (1) and structural units (2), respectively. The structural units (1) and (2) are typically randomly arranged in the molecular chain of the water-soluble polymer.

In the structural unit (1) and the structural unit (2), R ¹ Represents a hydrogen atom or a methyl group, preferably a hydrogen atom. In the plurality of structural units (1), R ¹ May be the same as or different from each other. In the structural unit (1) and the structural unit (2), R ¹ May be the same as or different from each other. By having the structural unit (1), the glass transition temperature of the water-soluble polymer is lowered, and the softness at room temperature is improved. The water-soluble polymer is capable of being dissolved in water by having the structural unit (2). The water-soluble polymer can be a raw material for an excellent water-soluble adhesive by having the structural units (1) and (2).

In the structural unit (1), R is as follows ² The alkyl group represented is preferably an alkyl group having 1 to 10 carbon atoms, more preferably a methyl group, an ethyl group, an n-butyl group, or a 2-ethylhexyl group. In the plurality of structural units (1), R ² May be the same as or different from each other.

In the structural unit (2), the cation represented by M is preferably an alkali metal cation or an alkaline earth metal cation, more preferably an alkali metal cation, and even more preferably a potassium cation or a sodium cation. M in the plurality of structural units (2) may be the same as or different from each other.

The content of the structural unit (1) in the water-soluble polymer is preferably 1% by weight or more, more preferably 3% by weight or more, still more preferably 5% by weight or more, particularly preferably 10% by weight or more, and the upper limit is preferably 95% by weight or less, more preferably 90% by weight or less, still more preferably 85% by weight or less, particularly preferably 80% by weight or less.

The content of the structural unit (2) in the water-soluble polymer is preferably 5% by weight or more, more preferably 10% by weight or more, still more preferably 15% by weight or more, particularly preferably 20% by weight or more, and the upper limit is preferably 95% by weight or less, more preferably 90% by weight or less, still more preferably 87% by weight or less, particularly preferably 85% by weight or less.

The content ratio of the structural unit (1) is preferably 5 wt% or more, more preferably 7 wt% or more, still more preferably 10 wt% or more, and the upper limit value is preferably 95 wt% or less, more preferably 90 wt% or less, still more preferably 93 wt% or less, and particularly preferably 90 wt% or less, relative to the total of the structural unit (1) and the structural unit (2).

The content of the structural unit can be measured by, for example, FT-IR method, NMR method, or titration method.

The water-soluble polymer according to the embodiment of the present invention can be suitably used as a raw material for various industrial products. The water-soluble polymer of the embodiment of the present invention may be suitably used as a raw material of an adhesive or a raw material of a water-absorbent polymer.

Method for producing Water-absorbent Polymer 3

As the method for producing the water-absorbent polymer according to the embodiment of the present invention, there are a method for producing the water-absorbent polymer using the water-soluble polymer obtained by the method for producing the water-soluble polymer according to the embodiment of the present invention (hereinafter, referred to as "production method a" in some cases) and a method for directly producing the water-absorbent polymer from the binder as waste (hereinafter, referred to as "production method B" in some cases).

3-1 Process for producing A)

In the method a for producing a water-absorbent polymer according to one embodiment of the present invention, the water-soluble polymer obtained by the method for producing a water-soluble polymer according to the embodiment of the present invention is reacted with a crosslinking agent. By reacting a water-soluble polymer with a crosslinking agent, water-absorbing properties can be imparted to the polymer.

The crosslinking agent is an internal crosslinking agent and can react with the structural units of the water-soluble polymer. The amount of the crosslinking agent to be used is preferably 0.1 to 200 parts by weight, more preferably 1 to 150 parts by weight, still more preferably 1 to 100 parts by weight, based on 100 parts by weight of the water-soluble polymer.

Examples of the crosslinking agent include polymerizable crosslinking agents, reactive crosslinking agents, and crosslinking agents having both of these properties.

The polymerizable crosslinking agent is capable of reacting with the ethylenically unsaturated double bond contained in the water-soluble polymer. Specific examples of the polymerizable crosslinking agent include compounds having at least 2 polymerizable double bonds in the molecule, such as N, N' -methylenebisacrylamide, (poly) ethyleneglycol di (meth) acrylate, (polyoxyethylene) trimethylolpropane tri (meth) acrylate, and poly (meth) allyloxyalkane.

The reactive crosslinking agent is capable of reacting with a carboxyl group contained in the water-soluble polymer (more specifically, a-COOM group in the above-mentioned structural unit (2)). Specific examples of the reactive crosslinking agent include covalent bonding crosslinking agents such as polyglycidyl ether (ethylene glycol diglycidyl ether and the like), polyhydric alcohols (ethylene glycol, polyethylene glycol, propylene glycol, glycerin, sorbitol and the like), ionic bonding crosslinking agents as polyvalent metal compounds such as aluminum, melamine resin crosslinking agents, amino resin crosslinking agents, peroxide crosslinking agents, and the aforementioned polyfunctional isocyanate crosslinking agents.

The crosslinking agent may be used in an amount of 1 or 2 or more.

The crosslinking agent is preferably a reactive crosslinking agent, and more preferably ethylene glycol or polyethylene glycol.

In the method a for producing a water-absorbent polymer according to one embodiment of the present invention, a crosslinking agent is typically added to a solution of a water-soluble polymer (or a dispersion of a water-soluble polymer).

In a preferred embodiment, the crosslinking agent is added to the solution of the water-soluble polymer (or the dispersion of the water-soluble polymer), followed by stirring. As the stirring method, any suitable stirring method can be suitably employed.

In a preferred embodiment, the water-soluble polymer is reacted with the crosslinking agent in the adhesive treatment liquid (adhesive treatment liquid containing a liquid having a hansen solubility parameter value of 31 or less and an alkaline compound, and having a concentration of the alkaline compound of 0.001 to 20% by weight). This allows the polymer to react with the crosslinking agent while further hydrolyzing (including saponification) the water-soluble polymer, and thus enables the water-absorbent polymer to be produced smoothly.

The binder treatment liquid suitable for use in the production of the water-absorbent polymer (hereinafter referred to as a water-absorbent polymer production treatment liquid) preferably contains 1% by volume or more and 90% by volume or less of an alcohol, more preferably 1% by volume or more and 80% by volume or less, still more preferably 1% by volume or more and 70% by volume or less, still more preferably 1% by volume or more and 60% by volume or less, particularly preferably 1% by volume or more and 50% by volume or less, and most preferably 1% by volume or more and 40% by volume or less. If the binder treatment liquid contains an alcohol, saponification reaction and transesterification reaction of the alcohol can be performed in the production of the water-absorbent polymer, and the reactivity of the polymer with the crosslinking agent can be appropriately adjusted.

The water-absorbent polymer production treatment liquid preferably has a hansen solubility parameter value of 10 to 29, a concentration of the basic compound of 0.01 to 8 wt%, more preferably a hansen solubility parameter value of 13 to 25, and a concentration of the basic compound of 0.5 to 5 wt%. In the treatment liquid for producing a water-absorbent polymer, when the hansen solubility parameter value of the liquid and the concentration of the basic compound are in the above ranges, saponification and transesterification can be performed in a well-balanced manner, and a water-absorbent polymer can be stably produced. If the hansen solubility parameter value of the liquid and/or the concentration of the basic compound are out of the above-described ranges, the saponification reaction may be too dominant as compared with the transesterification reaction. In this case, the reaction of the crosslinking agent with the polymer (or the adhesive) concentrates on the surface of the polymer (or the adhesive), and the water-absorbent polymer may not be produced.

In a preferred embodiment, the temperature at which the water-soluble polymer reacts with the crosslinking agent in the adhesive treatment liquid is preferably 15℃or higher, more preferably 20℃or higher, still more preferably 25℃or higher, still more preferably 30℃or higher, particularly preferably 35℃or higher, most preferably 40℃or higher, and the upper limit is preferably 80℃or lower, more preferably 70℃or lower, still more preferably 60℃or lower. When the temperature at which the water-soluble polymer and the crosslinking agent react in the binder treatment liquid is within the above range, the water-absorbent polymer can be easily and smoothly produced from the water-soluble polymer and the crosslinking agent under mild conditions. By reacting around transesterification, a water-absorbent polymer can be efficiently produced. The activation energy required for the transesterification reaction is lower than that of saponification, and thus the reaction can be appropriately controlled by performing the reaction or the like at a temperature in the above-mentioned range (preferably 15 to 80 ℃).

According to the method a for producing a water-absorbent polymer of one embodiment of the present invention, a water-absorbent polymer can be easily obtained from a binder as waste through a water-soluble polymer under mild conditions. This is presumably because, according to the method A for producing a water-absorbent polymer according to one embodiment of the present invention, the water-soluble polymer (particularly the-COOM group in the structural unit (2)) and the crosslinking agent are simply carried out under mild conditions, and as a result, the water-absorbent polymer can be obtained.

3-2 Process for production B

As another embodiment of the method B for producing a water-absorbent polymer according to the present invention, the aforementioned adhesive treatment liquid (comprising a liquid having a hansen solubility parameter value of 31 or less and an alkali compound, and an adhesive treatment liquid having a concentration of the alkali compound of 0.001 to 20% by weight), a crosslinking agent, and an adhesive are brought into contact.

The contact form of the adhesive treatment liquid, the crosslinking agent and the adhesive may be any suitable contact form within a range that does not impair the effects of the present invention. Examples of such contact forms include a form in which a crosslinking agent is added to a pressure-sensitive adhesive treatment liquid, and then a pressure-sensitive adhesive is added thereto to bring them into contact with each other; simultaneously adding a cross-linking agent and a binder into the binder treatment liquid to enable the cross-linking agent and the binder to be in contact; after the binder is added to the binder treatment liquid, a crosslinking agent is added to bring them into contact.

According to the production method B described above, the water-absorbent polymer can be simply and directly obtained from the binder as waste under mild conditions.

In the method B for producing a water-absorbent polymer, the above-mentioned water-absorbent polymer production treatment liquid is preferably used as the binder treatment liquid.

The amount of the crosslinking agent to be added is preferably 0.1 to 200 parts by weight, more preferably 1 to 150 parts by weight, still more preferably 1 to 100 parts by weight, based on 100 parts by weight of the adhesive.

The temperature range at which the adhesive treatment liquid, the crosslinking agent and the adhesive are contacted is, for example, the same as the temperature range at which the water-soluble polymer and the crosslinking agent react in the adhesive treatment liquid.

Thus, according to the production method B, the water-absorbent polymer can be easily obtained from the binder under mild conditions. This is presumably because hydrolysis of the binder (including saponification reaction of an ester with a base to form a salt and an alcohol) is simply carried out under mild conditions, and reaction of a carboxyl group formed by hydrolysis (more specifically, a-COOM group in the above-mentioned structural unit (2)) with a crosslinking agent proceeds to obtain a water-absorbent polymer.

Water-absorbent Polymer 4

The water-absorbent polymer according to the embodiment of the present invention typically includes a structural unit (1) represented by the following formula, a structural unit (2) represented by the following formula, and a crosslinked structure formed by the reaction of the structural unit (1) and/or the structural unit (2) represented by the following formula with the crosslinking agent. The crosslinked structure is preferably formed by the reaction of the structural unit (2) represented by the following formula with the above-mentioned crosslinking agent,

R in the structural unit (1) and the structural unit (2) ¹ 、R ² M, R in the structural unit (1) and the structural unit (2) in the above water-soluble polymer can be cited ¹ 、R ² 、MIs described in (2).

The content ratio of the structural unit (1) in the water-absorbent polymer can be referred to as an explanation of the content ratio of the structural unit (1) in the water-soluble polymer.

The range of the sum of the content ratio of the structural unit (2) and the crosslinked structure in the water-absorbent polymer can be cited as an explanation of the content ratio range of the structural unit (2) in the above-mentioned water-soluble polymer.

The content of the crosslinked structure in the water-absorbent polymer is preferably 1% by weight or more, more preferably 3% by weight or more, still more preferably 5% by weight or more, particularly preferably 7% by weight or more, and the upper limit is preferably 90% by weight or less, more preferably 85% by weight or less, still more preferably 80% by weight or less, particularly preferably 75% by weight or less.

The content ratio of the structural unit (1) is preferably 3 wt% or more, more preferably 5 wt% or more, still more preferably 7 wt% or more, particularly preferably 10 wt% or more, and the upper limit value is preferably 95 wt% or less, more preferably 90 wt% or less, still more preferably 85 wt% or less, particularly preferably 80 wt% or less, with respect to the total sum of the structural unit (1) and the structural unit (2).

The water-absorbent polymer according to the embodiment of the present invention can be obtained by any suitable method within a range that does not impair the effects of the present invention. Examples of such a method include a method for producing a water-absorbent polymer according to an embodiment of the present invention.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The test and evaluation methods in examples and the like are as follows. When "part" is described, it means "part by weight" unless otherwise specified, and when "%" is described, it means "% by weight" unless otherwise specified.

< preparation of adhesive tape >

The following adhesive tape was prepared.

"E-MASK" series (manufactured by Nito electric Co., ltd.), product No. RP108C, acrylic adhesive

"E-MASK" series (manufactured by Nito electric Co., ltd.), product number RP207, acrylic adhesive

REVALPHA series (manufactured by Nito electric Co., ltd.), product No.3195MS (N), acrylic adhesive

Adhesive tape for floor care (manufactured by Nitton Co., ltd.), product No.395N, acrylic adhesive

NITOFLON series (manufactured by Nidong electric Co., ltd.), product No.973UL, and silicone-based adhesive

< preparation of adhesive treatment liquid >

Preparation example 1

To 1-butanol (HSP value=23.2), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 0.5 mass%, to obtain an adhesive treatment liquid (1). Summarized in table 1.

Preparation example 2

To a mixed solvent (HSP value=20.0) of cyclopentyl methyl ether (Cpme)/methanol=70/30 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 1.3 wt%, to obtain a binder treatment liquid (2). Summarized in table 1.

[ preparation example 3]

To a mixed solvent (HSP value=19.5) of cyclopentyl methyl ether (Cpme)/ethanol=70/30 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 1.3 wt%, to obtain a binder treatment liquid (3). Summarized in table 1.

Preparation example 4

To a mixed solvent (HSP value=18.9) of cyclopentyl methyl ether (Cpme)/2-propanol (IPA) =70/30 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 1.3 wt%, to obtain a binder treatment liquid (4). Summarized in table 1.

Preparation example 5

To a mixed solvent (HSP value=18.8) of cyclopentyl methyl ether (Cpme)/1-butanol=70/30 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 1.3 wt%, to obtain a binder treatment liquid (5). Summarized in table 1.

Preparation example 6

To a mixed solvent (HSP value=18.7) of cyclopentyl methyl ether (Cpme)/benzyl alcohol=70/30 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 1.3 wt%, to obtain a binder treatment liquid (6). Summarized in table 1.

Preparation example 7

To a mixed solvent (HSP value=18.7) of toluene/methanol=80/20 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 1.0 wt%, to obtain a binder treatment liquid (7). Summarized in table 1.

Preparation example 8

To a mixed solvent (HSP value=18.4) of toluene/1-butanol=80/20 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 1.0 wt%, to obtain a binder treatment liquid (8). Summarized in table 1.

[ preparation example 9]

To a mixed solvent (HSP value=24.8) of ethanol/1-butanol=50/50 (volume ratio), sodium ethoxide (NaOEt) was added so that the alkali concentration in the obtained treatment liquid became 5.0 wt%, to obtain a binder treatment liquid (9). Summarized in table 1.

Preparation example 10

To a mixed solvent (HSP value=15.3) of heptane/EKINEN (registered trademark) (F-6, japan Alcohol Trading co., LTD) =95/5 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 2.0 wt%, to obtain a binder treatment liquid (10). Summarized in table 1.

Preparation example 11

To a mixed solvent (HSP value=15.5) of heptane/EKINEN (registered trademark) (F-6, japan Alcohol Trading co., LTD) =90/10 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 2.0 wt%, to obtain a binder treatment liquid (11). Summarized in table 1.

Preparation example 12

To a mixed solvent (HSP value=17.7) of cyclopentyl methyl ether (Cpme)/methanol=50/50 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 10 wt%, to obtain a binder treatment liquid (12). Summarized in table 1.

Preparation example 13

To a mixed solvent (HSP value=17.7) of cyclopentyl methyl ether (Cpme)/methanol=50/50 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 14 wt%, to obtain a binder treatment liquid (13). Summarized in table 1.

PREPARATION EXAMPLE 14

To a mixed solvent (HSP value=23.2) of Methyl Ethyl Ketone (MEK)/methanol=50/50 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 20 wt%, to obtain a binder treatment liquid (14). Summarized in table 1.

Preparation example 15

To a mixed solvent (HSP value=29.5) of 1-butanol/methanol/water=40/40/20 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 1.3 wt%, to obtain a binder treatment liquid (15). Summarized in table 1.

Preparation example 16

To a mixed solvent (HSP value=21.2) of Methyl Ethyl Ketone (MEK)/methanol=70/30 (volume ratio), sodium hydroxide (NaOH) was added so that the alkali concentration in the obtained treatment liquid became 0.8 wt%, to obtain a binder treatment liquid (16). Summarized in table 1.

Preparation example 17

To a mixed solvent (HSP value=21.2) of Methyl Ethyl Ketone (MEK)/methanol=70/30 (volume ratio), sodium hydroxide (NaOH) was added so that the alkali concentration in the obtained treatment liquid became 1.3 wt%, to obtain a binder treatment liquid (17). Summarized in table 1.

PREPARATION EXAMPLE 18

To a mixed solvent (HSP value=21.2) of Methyl Ethyl Ketone (MEK)/methanol=70/30 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 5.0 wt%, to obtain a binder treatment liquid (18). Summarized in table 1.

Preparation example 19

To a mixed solvent (HSP value=18.8) of decane/butanol=40/60 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 1.5 wt%, to obtain a binder treatment liquid (19). Summarized in table 1.

PREPARATION EXAMPLE 20

To a mixed solvent (HSP value=28.9) of 1-butanol/methanol/water=60/20/20 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 5.0 wt%, to obtain a binder treatment liquid (20). Summarized in table 1.

Preparation example 21

To a mixed solvent (HSP value=26.9) of 1-butanol/2-propanol (IPA)/water=70/10/20 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 5.0 wt%, to obtain a binder treatment liquid (21). Summarized in table 1.

PREPARATION EXAMPLE 22

To a mixed solution (HSP value=34.0) of ethanol/water=65/35 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment solution became 0.5 wt%, to obtain a binder treatment solution (C1). Summarized in table 1.

Preparation example 23

A mixed solvent of cyclopentyl methyl ether (Cpme)/methanol=50/50 (volume ratio) (HSP value=17.7) was used as the binder treatment liquid (C2). Summarized in table 1.

PREPARATION EXAMPLE 24

To a mixed solvent (HSP value=23.2) of Methyl Ethyl Ketone (MEK)/methanol=50/50 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 25.0 wt%, to obtain a binder treatment liquid (C3). Summarized in table 1.

Preparation example 25

To a mixed solvent (HSP value=33.5) of benzyl alcohol/methanol/water=40/20/40 (volume ratio), potassium hydroxide (KOH) was added so that the alkali concentration in the obtained treatment liquid became 1.3 wt%, to obtain a binder treatment liquid (C4). Summarized in table 1.

TABLE 1

Examples 1 to 18 and comparative examples 1 to 4

< production of Water-soluble Polymer >

The adhesive constituting the adhesive layer was separated from the base material by pressing the abrasive belt of a belt sander (BE-3210, manufactured by Muta) equipped with an abrasive belt (particle size= #100, manufactured by RYOBI) against the adhesive belt shown in Table 2 at a belt speed of 5.8 m/sec.

The separated adhesive 0.7g was put into a vial, to which 20g of the adhesive treatment liquid was added, and stirred at 50℃for 12 hours at a stirring speed of 600 rpm. Then, the solvent was removed by decantation to obtain a polymer. To the resulting polymer, a large amount of water was added to evaluate the solubility in water. The results are shown in Table 2.

And (2) the following steps: completely dissolved in water.

Delta: substantially soluble in water but with a few residues.

X: not dissolved in water.

Next, the polymers obtained in examples 2, 4 and 5 were analyzed by IR and/or NMR, and confirmed to be water-soluble polymers having the following structural units. The content ratio of the structural unit (I) to the structural unit (II) in the water-soluble polymer produced from the acrylic adhesive of "E-MASK" RP108C (manufactured by Nito electric Co., ltd.) is shown in Table 2.

Wherein R is ¹ Represents a hydrogen atom, R ² An alkyl group having 1 to 4 carbon atoms, and M represents a hydrogen atom or a cation.

TABLE 2

Examples 19 to 31 and comparative examples 5 to 8]

The adhesive constituting the adhesive layer was separated from the base material by pressing the abrasive belt of a belt sander (BE-3210, manufactured by Muta) equipped with an abrasive belt (particle size= #100, manufactured by RYOBI) against the adhesive belt shown in Table 3 at a belt speed of 5.8 m/sec.

The separated adhesive (0.7 g) was placed in a 50mL sample tube, 20g of the adhesive-treated liquid obtained in each preparation example shown in Table 3 was added thereto, 0.1g of the crosslinking agent shown in Table 3 (examples 30 and 31 were 0.01 g) was added thereto, and the mixture was stirred at 50℃for 12 hours at a stirring speed of 600 rpm. Thus, a water-absorbent polymer was obtained.

Then, the solvent was removed by decantation, and the water-absorbent polymer was dried at 120℃for 1.5 hours.

Next, the dried water-absorbent polymer was pulverized in a mortar, and the water absorption was evaluated by JIS K7223-1996 (tea bag method). The results are shown in Table 3.

And (2) the following steps: the water absorption rate is more than 10 times.

X: the water absorption is less than 10 times.

TABLE 3

The crosslinking agent in table 3 is abbreviated as follows.

EG; ethylene glycol

PEG-200; polyethylene glycol (number average molecular weight Mn 200)

PEG-400; polyethylene glycol (number average molecular weight Mn 400)

Industrial applicability

The method for producing a water-soluble polymer and the method for producing a water-absorbent polymer according to the embodiments of the present invention can produce a water-soluble polymer and a water-absorbent polymer from various binders under mild conditions, and therefore can be applied to recycling of wastes of binders, which are produced in large quantities in a production site or the like.

Claims

1. A method for producing a water-soluble polymer, wherein a binder treatment liquid is brought into contact with a binder, the binder treatment liquid containing a liquid having a Hansen solubility parameter value of 31 or less and an alkaline compound, and the concentration of the alkaline compound in the binder treatment liquid is 0.001 to 20% by weight.

2. The method for producing a water-soluble polymer according to claim 1, wherein the hansen solubility parameter value of the liquid is 15 or more and 25 or less, and the liquid contains a lower alcohol.

3. The method for producing a water-soluble polymer according to claim 1 or 2, wherein the adhesive is composed of an acrylic adhesive.

4. The method for producing a water-soluble polymer according to any one of claims 1 to 3, wherein the concentration of the alkaline compound in the treatment liquid is 0.01 to 10% by weight.

5. A water-soluble polymer obtained by the process for producing a water-soluble polymer according to any one of claims 1 to 4, comprising a structural unit (1) represented by the following formula and a structural unit (2) represented by the following formula,

6. A method for producing a water-absorbent polymer, wherein the water-soluble polymer obtained by the method for producing a water-soluble polymer according to any one of claims 1 to 4 is reacted with a crosslinking agent.

7. A method for producing a water-absorbent polymer, wherein a binder treatment liquid, a crosslinking agent and a binder are brought into contact, the binder treatment liquid containing a liquid having a Hansen solubility parameter value of 31 or less and a basic compound, and the concentration of the basic compound in the binder treatment liquid being 0.001 to 20% by weight.

8. A water-absorbent polymer comprising a structural unit (1) represented by the following formula, a structural unit (2) represented by the following formula, and a crosslinked structure formed by the reaction of the structural unit (1) and/or the structural unit (2) with a crosslinking agent,