WO2023195297A1 - Adhesive for optical film, coating, and optical film - Google Patents

Adhesive for optical film, coating, and optical film Download PDF

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Publication number
WO2023195297A1
WO2023195297A1 PCT/JP2023/008694 JP2023008694W WO2023195297A1 WO 2023195297 A1 WO2023195297 A1 WO 2023195297A1 JP 2023008694 W JP2023008694 W JP 2023008694W WO 2023195297 A1 WO2023195297 A1 WO 2023195297A1
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WO
WIPO (PCT)
Prior art keywords
polyurethane resin
polyol
mass
adhesive
acid
Prior art date
Application number
PCT/JP2023/008694
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French (fr)
Japanese (ja)
Inventor
文弥 金子
早季子 藤原
成相 廣瀬
Original Assignee
第一工業製薬株式会社
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Filing date
Publication date
Priority claimed from JP2022151908A external-priority patent/JP2023152588A/en
Application filed by 第一工業製薬株式会社 filed Critical 第一工業製薬株式会社
Publication of WO2023195297A1 publication Critical patent/WO2023195297A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/08—Processes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/30—Low-molecular-weight compounds
    • C08G18/34—Carboxylic acids; Esters thereof with monohydroxyl compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/42—Polycondensates having carboxylic or carbonic ester groups in the main chain
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
    • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/72—Polyisocyanates or polyisothiocyanates
    • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
    • C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
    • C09J175/04—Polyurethanes
    • C09J175/06—Polyurethanes from polyesters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/35—Heat-activated
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics

Definitions

  • the present invention relates to adhesives for optical films, coatings, and optical films.
  • Polyurethane resin aqueous dispersions can form coating films with excellent mechanical properties, solvent resistance, and water resistance, so they are used in a wide range of fields such as water-based coating agents and adhesives. From this point of view, the development of polyurethane resin aqueous dispersions with improved dispersibility and polyurethane resin compositions that can exhibit various functions in films when used as adhesives is actively underway.
  • Patent Document 1 discloses a technique for producing an aqueous polyurethane resin dispersion by reacting raw materials containing a hydroxyl- and/or carboxyl-terminated fluoropolyether and a polyisocyanate in water. .
  • the aqueous polyurethane resin dispersion thus obtained is said to be capable of forming a film that has not only water repellency, oil repellency, and stain resistance, but also excellent blocking resistance and surface smoothness.
  • Polyurethane resin water dispersions are widely used as adhesives in various fields such as optical films, but conventional adhesives using polyurethane resin water dispersions do not have sufficient adhesion to substrates. However, there was still room for improvement. In particular, conventional adhesives using polyurethane resin water dispersions have a problem in that their adhesion is significantly reduced when placed in a high humidity and heat environment. From this point of view, there has been a demand for adhesives for optical films containing polyurethane resin aqueous dispersions to have the ability to further enhance adhesion to substrates even under high humidity and heat environments.
  • the present invention has been made in view of the above, and aims to provide an adhesive for optical films, a coating, and an optical film that can improve adhesion to a substrate even in a high humidity and heat environment. do.
  • the present inventors discovered that the above object could be achieved by introducing a structural unit derived from a specific polyol into a polyurethane resin, leading to the completion of the present invention. .
  • the present invention includes, for example, the subject matter described in the following sections.
  • Item 1 An adhesive for optical films containing an aqueous dispersion containing a polyurethane resin (X),
  • the polyurethane resin (X) has at least a structural unit derived from the polyol (A) and a structural unit derived from the polyisocyanate (B),
  • the polyol (A) includes a polyester polyol (a) having a structure derived from terephthalic acid and a structure derived from neopentyl glycol, and dimethylolpropionic acid (b),
  • the polyol (A) contains 85% by mass or more of the polyester polyol (a)
  • the weight average molecular weight of the polyurethane resin (X) is 5000 to 50000
  • the polyurethane resin (X) contains 98% by mass or more of a bifunctional component
  • the polyurethane resin (X) is an adhesive for optical films, and has an acid value of 5
  • Section 2 Item 2.
  • Section 3 Item 3.
  • a film comprising a dried adhesive for optical films according to item 1 or 2.
  • Section 4 Item 3.
  • An optical film comprising the film according to item 3 as an adhesive layer.
  • the adhesive for optical films of the present invention can improve adhesion to a substrate even under a high humidity and heat environment.
  • the adhesive for optical films of the present invention contains an aqueous dispersion containing a polyurethane resin (X).
  • the polyurethane resin (X) has at least a structural unit derived from polyol (A) and a structural unit derived from polyisocyanate (B), and the polyol (A) has a structure derived from terephthalic acid and a structure derived from neopentyl glycol. and dimethylolpropionic acid (b).
  • the polyol (A) contains 85% by mass or more of the polyester polyol (a), the weight average molecular weight of the polyurethane resin (X) is 5,000 to 50,000, and the polyurethane resin (X) is a bifunctional component.
  • the polyurethane resin (X) has an acid value of 5 to 15 mgKOH/g. Note that "the polyurethane resin (X) contains 98% by mass or more of a bifunctional component,” means “the polyurethane resin (X) contains 98% by mass of structural units derived from a bifunctional compound.” It can be read as "containing or more.”
  • the adhesive for optical films of the present invention contains the polyurethane resin (X), it is possible to form an adhesive that has excellent adhesion to the base material, and even in a high humidity and heat environment. It is possible to form an adhesive with excellent adhesion.
  • the polyurethane resin (X) has at least a structural unit derived from the polyol (A).
  • the polyol (A) is a composition containing at least two kinds of compounds having multiple hydroxyl groups (preferably, compounds having two hydroxyl groups).
  • the polyol (A) includes at least a polyester polyol (a) having a structure derived from terephthalic acid and a structure derived from neopentyl glycol, and dimethylolpropionic acid (b).
  • the adhesive for optical films of the present invention can form an adhesive that has excellent adhesion to a base material even under a high humidity and heat environment.
  • dimethylolpropionic acid (b) is a compound having two hydroxyl groups, such a compound is a bifunctional compound.
  • the polyester polyol (a) is, for example, a compound formed by a dehydration condensation reaction between a glycol compound and a carboxyl group-containing compound, and has a structure derived from glycol and a structure derived from the carboxyl group-containing compound. Therefore, in the present invention, the polyester polyol (a) is a polyester polyol compound that can be formed, for example, by a dehydration condensation reaction of a glycol including neopentyl glycol and a carboxyl group-containing compound including terephthalic acid.
  • the polyester polyol (a) can contain a structure derived from another compound in addition to the structure derived from terephthalic acid and the structure derived from neopentyl glycol, as long as the effects of the present invention are not impaired.
  • Such other compounds can include, for example, a wide range of compounds used for producing known polyester polyols, such as isophthalic acid, adipic acid, succinic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, Maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid , naphthalic acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-
  • the polyester polyol (a) further has a structure derived from at least one compound selected from the group consisting of adipic acid and ethylene glycol.
  • the adhesive for optical films of the present invention can improve adhesion to the substrate even under a high humidity and heat environment.
  • the content ratio of the structure derived from terephthalic acid and the structure derived from neopentyl glycol is not particularly limited.
  • the content of the structure derived from terephthalic acid is preferably 10 to 70% by mass, more preferably 10 to 60% by mass, and 15 to 45% by mass with respect to the total structural units of the polyester polyol (a). % is more preferable.
  • the content of the structure derived from neopentyl glycol is preferably 20 to 60% by mass, more preferably 30 to 55% by mass, based on the total structural units of the polyester polyol (a).
  • the content ratio of the structure derived from the other compound is not particularly limited.
  • the content of structures derived from other compounds is preferably 5 to 50% by mass, more preferably 7 to 48% by mass, and 10 to 48% by mass, based on the total structural units of polyester polyol (a). More preferably, it is 45% by mass.
  • the content of the structure derived from terephthalic acid and the structure derived from neopentyl glycol is preferably 50 to 95% by mass, and preferably 52 to 93% by mass, based on the total structural units of the polyester polyol (a). is more preferable, and even more preferably 55 to 90% by mass.
  • the polyester polyol (a) has a structure derived from at least one carboxylic acid compound selected from the group consisting of terephthalic acid and adipic acid
  • the content ratio of these structures is not particularly limited, and for example, the polyester polyol It is preferably 70% by mass or less, more preferably 60% by mass or less, based on the total structural units of (a).
  • the polyester polyol (a) has a structure derived from ethylene glycol
  • the content of such a structure is not particularly limited, and is, for example, 5% by mass or less based on the total structural units of the polyester polyol (a).
  • the content is preferably 3% by mass or less, and more preferably 3% by mass or less.
  • the polyester polyol (a) preferably contains 98% by mass or more, more preferably 99% by mass or more of a bifunctional polyester polyol. In these cases, the remainder may be, for example, a trifunctional or higher functional polyester polyol.
  • the polyester polyol (a) may consist only of a bifunctional polyester polyol.
  • the number average molecular weight of the polyester polyol (a) is not particularly limited, for example, preferably 500 or more, more preferably 1000 or more, even more preferably 1500 or more, and preferably 5000 or less, more preferably 4000 or less, 3000 or less. is even more preferable.
  • the polyester polyol (a) contained in the polyol (A) may be used alone or in combination of two or more.
  • polyester polyol (a) can be obtained, for example, by a method similar to a known manufacturing method, or can be obtained from a commercially available product.
  • polyester polyol (a) can be produced by a dehydration condensation reaction between a glycol compound and a carboxyl group-containing compound.
  • the polyol (A) can also contain other polyol compounds in addition to the polyester polyol (a) and dimethylolpropionic acid (b).
  • Other polyol compounds can include a wide range of known polyols, such as polyester polyol compounds other than polyester polyol (a), polycarbonate polyols, polyether polyols, hydrocarbon polyols, or low molecular weight polyols with a molecular weight of 400 or less, Compounds containing at least one active hydrogen group and one or more carboxy groups (or salts thereof) other than dimethylolpropionic acid (b) can be mentioned.
  • the polycarbonate polyol is not particularly limited, and for example, a wide range of known polycarbonate polyols for forming urethane resins can be mentioned.
  • polycarbonate polyols include compounds obtained by reacting glycols such as 1,4-butanediol, 1,6-hexanediol, and diethylene glycol with diphenyl carbonate and phosgene.
  • Polycarbonate polyol can be obtained, for example, by a method similar to a known manufacturing method, or can be obtained from a commercially available product.
  • the polyether polyol is not particularly limited, and for example, a wide range of known polyether polyols for forming urethane resins can be mentioned.
  • a polyether polyol formed by addition polymerizing a polyol compound and an alkylene oxide can be mentioned.
  • the polyol compound for forming the polyester polyol include various aliphatic polyols and alicyclic polyols.
  • the alkylene oxide include alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide.
  • the polyether polyol can be obtained, for example, by a method similar to a known manufacturing method, or can be obtained from a commercially available product. Commercially available products include, for example, the "Newport BPE" (registered trademark) series manufactured by Sanyo Chemical Co., Ltd.
  • the hydrocarbon polyol is not particularly limited, and includes a wide range of known hydrocarbon polyols for forming urethane resins.
  • the hydrocarbon polyol has a hydrocarbon chain terminated with a hydroxyl group, such as polybutadiene polyol, polyisoprene polyol, hydrogenated polybutadiene polyol, or hydrogenated polyisoprene polyol.
  • low molecular weight polyols having a molecular weight of 400 or less examples include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, neopentyl glycol, 1,3-butanediol, and 1,4-propylene glycol.
  • Compounds containing at least one active hydrogen group and one or more carboxyl groups (or their salts) are, for example, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, dimethylolpropionic acid (b), etc.
  • Examples include carboxylic acid-containing compounds such as oxymaleic acid, 2,6-dioxybenzoic acid, 3,4-diaminobenzoic acid, derivatives thereof, and salts thereof.
  • Other compounds containing at least one active hydrogen group and one or more carboxyl groups include amino acids such as alanine, aminobutyric acid, aminocaproic acid, glycine, glutamic acid, aspartic acid, and histidine, succinic acid, and adipic acid. , maleic anhydride, phthalic acid, trimellitic anhydride, and other carboxylic acids.
  • the polyol (A) contains 85% by mass or more of the polyester polyol (a). That is, the content of the polyester polyol (a) is 85% by mass or more based on the total mass of the polyol (A).
  • the adhesive for optical films of the present invention can form an adhesive that has excellent adhesion to a base material even under a high humidity and heat environment.
  • the content of the polyester polyol (a) is less than 85% by mass with respect to the total mass of the polyol (A), the adhesion to the base material in a high humidity and heat environment decreases. It is more preferable that the polyol (A) contains 85% by mass or more of the bifunctional polyester polyol (a).
  • the total mass of polyol (A) means the total mass of polyester polyol (a), dimethylolpropionic acid (b), and other polyol compounds (compounds having two or more hydroxyl groups).
  • the polyol (A) preferably contains 87% by mass or more, more preferably 90% by mass or more, and preferably 92% by mass or more of polyester polyol (a) (preferably bifunctional polyester polyol (a)). More preferably, it is particularly preferably contained in an amount of 95% by mass or more.
  • the polyol (A) preferably contains 99% by mass or less, more preferably 97% by mass or less of polyester polyol (a) (preferably bifunctional polyester polyol (a)).
  • the content of dimethylolpropionic acid (b) is preferably 1 to 10 parts by mass, more preferably 2 to 8 parts by mass, per 100 parts by mass of the total mass of polyester polyol (a). It is more preferably 5 to 7 parts by weight, particularly preferably 3 to 6 parts by weight. Note that dimethylolpropionic acid is also referred to as "2,2-dimethylolpropionic acid.”
  • the polyol (A) can also contain a trifunctional or higher-functional low chain polyol, but this content is preferably 0.75% by mass or less, and 0.40% by mass or less based on the total mass of the polyol (A). It is more preferably at most 0.30% by mass, even more preferably at most 0.30% by mass.
  • the adhesive for optical films of the present invention has excellent adhesion to the substrate even under a high humidity and heat environment.
  • trifunctional or higher-functional low-chain polyol compounds include polyhydric alcohols with a molecular weight of 150 or less, and specific examples include trimethylolpropane and pentaerythritol.
  • the polyol (A) does not need to contain a trifunctional or higher-functional low chain polyol.
  • the polyol (A) preferably contains 98% by mass or more, more preferably 99% by mass or more of a bifunctional polyol (that is, a polyol having two hydroxyl groups). In these cases, the remainder may be, for example, a trifunctional or higher functional polyol.
  • the polyol (A) may consist only of a bifunctional polyol.
  • the polyurethane resin (X) has a structural unit derived from the polyisocyanate (B).
  • the polyisocyanate (B) is not particularly limited, and can include a wide range of polyisocyanate compounds used for forming polyurethane resins, such as compounds having two or more isocyanate groups, A compound having two isocyanate groups is more preferred.
  • polyisocyanate (B) examples include bifunctional isocyanate compounds such as aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, and araliphatic diisocyanates.
  • aliphatic polyisocyanates examples include tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and 2-methylpentane.
  • Examples include -1,5-diisocyanate and 3-methylpentane-1,5-diisocyanate.
  • alicyclic polyisocyanate examples include isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate (hereinafter referred to as "H12MDI"), 1,4-cyclohexane diisocyanate, and methylcyclohexyl diisocyanate.
  • H12MDI 4,4'-dicyclohexylmethane diisocyanate
  • 1,4-cyclohexane diisocyanate examples include silane diisocyanate and 1,3-bis(isocyanatemethyl)cyclohexane.
  • aromatic polyisocyanates examples include tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, and 4,4'-diisocyanate.
  • aromatic polyisocyanates examples include benzyl diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, and 1,4-phenylene diisocyanate.
  • aromatic aliphatic polyisocyanate examples include dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, ⁇ , ⁇ , ⁇ , ⁇ -tetramethylxylylene diisocyanate, and the like.
  • a modified organic polyisocyanate may be used as the polyisocyanate (B).
  • the modified organic polyisocyanate is not particularly limited, and examples thereof include carbodiimide, allophanate, biuret, isocyanurate, and adduct.
  • polyisocyanate can also be used individually or in combination of 2 or more types.
  • the number average molecular weight of the polyisocyanate (B) is not particularly limited, but is preferably 100 or more and 400 or less, more preferably 120 or more and 300 or less, and more preferably 150 or more and 280 or less.
  • the polyisocyanate (B) is preferably an aromatic polyisocyanate, more preferably a bifunctional aromatic polyisocyanate.
  • the aromatic polyisocyanate is tolylene diisocyanate (TDI) or 4,4'-diphenylmethane diisocyanate (MDI).
  • Polyisocyanate (B) can be obtained by a known production method or can be obtained from a commercially available product.
  • the polyisocyanate may be used alone or in combination of two or more.
  • the polyisocyanate (B) preferably contains 98% by mass or more, more preferably 99% by mass or more of a bifunctional isocyanate. In these cases, the remainder may be, for example, a trifunctional or higher functional polyisocyanate.
  • the polyisocyanate (B) may consist only of a difunctional polyol.
  • the polyurethane resin (X) has a structural unit derived from the polyol (A) and a structural unit derived from the polyisocyanate (B).
  • the polyurethane resin (X) can also include, for example, a structure derived from a blocking agent or a structure derived from a chain extender, which will be described later.
  • the polyurethane resin (X) can also be formed only from structural units derived from the polyol (A) and structural units derived from the polyisocyanate (B).
  • the polyurethane resin (X) may have a structural unit derived from a compound having a monofunctional active hydrogen group, which will be described later.
  • the content thereof is preferably 5% by mass or less based on the total structural units of the polyurethane resin (X), and 3. It is more preferably at most 1% by mass, even more preferably at most 1% by mass.
  • the adhesive for optical films of the present invention has excellent adhesion to the substrate even under a high humidity and heat environment.
  • the polyurethane resin (X) may have a structural unit derived from a low-chain amine compound such as a polyamine (chain extender) used as a chain extender to be described later.
  • the content ratio of each structural unit is not particularly limited.
  • the polyurethane resin (X) should contain 5 to 50 parts by mass of structural units derived from polyisocyanate based on 100 parts by mass of the total mass of structural units derived from polyol (A) and structural units derived from polyisocyanate (B). is preferred, and more preferably 10 to 40 parts by mass.
  • the polyurethane resin (X) contains 98% by mass or more of a bifunctional component (that is, a structural unit derived from a bifunctional compound). As a result, the adhesive for optical films of the present invention has excellent adhesion to the substrate even under a high humidity and heat environment. It is preferable that the polyurethane resin (X) contains 99% by mass or more of a bifunctional component.
  • the polyurethane resin (X) may be formed only from bifunctional components.
  • the bifunctional constituent components are, for example, a bifunctional polyol (A) and a bifunctional polyisocyanate (B).
  • the content thereof is preferably 3% by mass or less with respect to the total mass of the polyurethane resin (X), and 0.75% by mass. It is more preferably at most 0.40% by mass, even more preferably at most 0.30% by mass.
  • the weight average molecular weight of the polyurethane resin (X) is 5,000 to 50,000.
  • the adhesive for optical films of the present invention has excellent adhesion to the substrate even under a high humidity and heat environment.
  • the weight average molecular weight of the polyurethane resin (X) is less than 5,000, the adhesive for optical films of the present invention has poor adhesion to the substrate in a high humidity and heat environment.
  • the weight average molecular weight of the polyurethane resin (X) exceeds 50,000, the adhesive for optical films of the present invention has poor adhesion to the substrate in a high humidity and heat environment.
  • the weight average molecular weight of the polyurethane resin (X) is determined using a GPC device using N,N-dimethylformamide (DMF) as a solvent, and is determined as a polystyrene equivalent value.
  • the specific measurement conditions are as follows. Column: Shodex OHPak SB-806M HQ Column temperature: 50°C Detector: Differential refractive index detector RID-20A (Shimadzu Corporation) Flow rate: 0.5 ml/min That is, in the present invention, the weight average molecular weight of the polyurethane resin is defined by the above measurement method, and particularly means the weight average molecular weight of the polyurethane resin as a solvent-soluble component.
  • the weight average molecular weight of the polyurethane resin (X) is preferably 7,000 or more, more preferably 8,000 or more, even more preferably 9,000 or more, and particularly preferably 10,000 or more. Further, the weight average molecular weight of the polyurethane resin (X) is preferably 48,000 or less, more preferably 45,000 or less, even more preferably 43,000 or less, and particularly preferably 40,000 or less.
  • the polyurethane resin (X) has an acid value of 5 to 15 mgKOH/g.
  • the adhesive for optical films of the present invention becomes an adhesive that has particularly excellent adhesion to the substrate even under a high humidity and heat environment. If the acid value is less than 5 mgKOH/g, the adhesion will not only deteriorate, but also make emulsification and dispersion difficult in the production of polyurethane resin (X), making it difficult to form an adhesive. If the acid value exceeds 15 mgKOH/g, the adhesion will decrease significantly.
  • the acid value of the polyurethane resin (X) is more preferably 7 mgKOH/g or more, even more preferably 8 mgKOH/g or more, and particularly preferably 9 mgKOH/g or more.
  • the acid value of the polyurethane resin (X) is more preferably 14 mgKOH/g or less, and even more preferably 13 mgKOH/g or less.
  • the method for adjusting the acid value is not particularly limited, and for example, a wide variety of known methods can be employed. For example, by adjusting the ratio of components constituting the polyol (A), the acid value of the polyurethane resin (X) can be adjusted.
  • the acid value of the polyurethane resin composition can be measured according to JIS K0070-1992.
  • the aqueous polyurethane resin dispersion contains the polyurethane resin (X) as a solid content and a solvent containing water as a medium.
  • the solvent may be water alone or a mixed solvent of water and a lower alcohol compound having 1 to 3 carbon atoms.
  • the content ratio of the polyurethane resin is not particularly limited.
  • the polyurethane resin can be contained in 10 to 50 parts by weight, preferably 20 to 40 parts by weight, per 100 parts by weight of the aqueous solvent.
  • the particle size of the polyurethane resin (X) is not particularly limited, and can be in the same range as the particle size of the polyurethane resin in known aqueous polyurethane resin dispersions for adhesives, for example.
  • the volume average particle diameter D50 of the polyurethane resin (X) is 1 to 500 nm, preferably 3 to 300 nm, more preferably 5 to 250 nm.
  • the aqueous polyurethane resin dispersion may contain components other than the polyurethane resin (X) and water, and for example, raw materials used in producing the aqueous polyurethane resin dispersion may remain.
  • raw materials include, for example, surfactants, unreacted monomers, unreacted chain extenders, by-products, catalysts, and the like.
  • the catalyst include metal catalysts and amine catalysts.
  • metal catalysts examples include tin catalysts such as dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dioctate, lead catalysts such as lead octylate, lead octenoate, and lead naphthenate, and bismuth such as bismuth octylate and bismuth neodecanoate.
  • tin catalysts such as dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dioctate
  • lead catalysts such as lead octylate, lead octenoate, and lead naphthenate
  • bismuth such as bismuth octylate and bismuth neodecanoate.
  • examples include catalysts.
  • the amine catalyst include tertiary amine compounds such as triethylene diamine.
  • the method for producing the polyurethane resin is not particularly limited, and for example, a wide variety of known production methods can be employed. In particular, it is preferable to manufacture the polyurethane resin by a manufacturing method using emulsification dispersion, which will be described later.
  • the method for producing an aqueous polyurethane resin dispersion is not particularly limited, and for example, a wide variety of known methods for producing an aqueous polyurethane resin dispersion can be employed.
  • a urethane prepolymer is prepared by mixing polyol (A) and polyisocyanate (B), and by emulsifying and dispersing this urethane prepolymer, polyurethane resin (X ) is produced, and an aqueous polyurethane resin dispersion can be obtained.
  • the mixing process can be performed in a solvent.
  • a solvent preferably has properties that are inert to isocyanate groups and capable of dissolving the urethane prepolymer produced.
  • examples of the solvent include dioxane, methyl ethyl ketone, dimethyl formamide, tetrahydrofuran, N-methyl-2-pyrrolidone, acetone, toluene, dioxane, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, and the like. It is preferable that the solvent used in the reaction is finally removed.
  • the temperature of the mixing treatment is not particularly limited, and can be, for example, 30°C to 130°C.
  • the time for the mixing treatment can be appropriately set depending on the temperature, and is, for example, 0.5 to 10 hours.
  • the reaction between the polyol (A) and the polyisocyanate (B) progresses through the mixing process, and a urethane prepolymer is produced.
  • a solvent is used for the mixing treatment, a urethane prepolymer solution is obtained.
  • the urethane prepolymer After the urethane prepolymer is produced and before emulsifying and dispersing it, it can be neutralized using a neutralizing agent, if necessary.
  • neutralizing agents examples include nonvolatile bases such as sodium hydroxide and potassium hydroxide, tertiary amines such as trimethylamine, triethylamine, dimethylethanolamine, methyldiethanolamine, and triethanolamine, and volatile bases such as ammonia. Can be mentioned.
  • a blocking agent can also be added to the urethane prepolymer solution before or after the neutralization treatment, preferably at the same time as the neutralization treatment.
  • the blocking agent has the effect of reacting with the remaining NCO groups and stopping the reaction. This facilitates adjustment of the molecular weight, etc. of the polyurethane resin (X).
  • As the blocking agent a wide variety of known blocking agents can be used. Examples include compounds having a monofunctional active hydrogen group. Specifically, monovalent alcohol compounds, monovalent amino compounds (for example, dibutylamine) is exemplified.
  • the amount of the blocking agent used can be 5 parts by mass or less, preferably 3 parts by mass or less, more preferably 1 part by mass or less, based on 100 parts by mass of the total mass of polyol (A) and polyisocyanate (B). More preferably, it is 0.8 parts by mass or less.
  • the amounts of polyol (A) and polyisocyanate (B) used are not particularly limited, and can be adjusted as appropriate depending on the composition of the target polyurethane resin.
  • the method for emulsifying and dispersing the urethane prepolymer obtained by the mixing treatment is not particularly limited, and a wide variety of known methods can be employed.
  • the urethane prepolymer can be emulsified and dispersed by mixing a solution of the urethane prepolymer with an aqueous solvent and applying shear using an emulsifying disperser such as a homogenizer.
  • the aqueous solvent may contain the neutralizing agent as required.
  • a chain extender can be added to extend the chain.
  • urea bonds are generated by the interfacial polymerization reaction between the isocyanate groups in the emulsified micelles and the chain extender, so that the crosslink density in the emulsified micelles is improved and a three-dimensional crosslinked structure is formed.
  • water molecules present in the system can cause chain extension when the urethane prepolymer is emulsified and dispersed in water.
  • the chain extender include the polyamines mentioned above. In this case, the polyurethane resin (X) finally produced has a structural unit derived from a polyamine.
  • polyamines chain extenders
  • diamine compounds include ethylenediamine, trimethylenediamine, piperazine, isophoronediamine, diethylenetriamine, dipropylenetriamine, and amino group-containing silane coupling agents
  • examples of polyamine compounds include diethylenetriamine, dipropylenetriamine, and triethylene. Examples include tetramine and the like.
  • the polyamine may also be a polycarbodiimide compound, such as a crosslinking agent for carbodilite aqueous resins manufactured by Nisshinbo Chemical Co., Ltd.
  • the amount used is not particularly limited, and for example, the equivalent ratio of the isocyanate group in the urethane prepolymer to the chain extender is 1:0.5 to 1:0.9.
  • the amount of chain extender used can be adjusted so that
  • surfactants can be used as necessary.
  • examples of the surfactant include nonionic surfactants, anionic surfactants, and cationic surfactants. These surfactants may be used alone or in combination of two or more.
  • the adhesive for optical films of the present invention contains a polyurethane resin water dispersion (a water dispersion containing polyurethane resin (X)).
  • the optical film adhesive of the present invention can have the same structure as known optical film adhesives as long as it contains a polyurethane resin aqueous dispersion.
  • the adhesive for optical films can also contain components such as other additives in addition to the polyurethane resin aqueous dispersion.
  • a film can be formed using the adhesive for optical film of the present invention.
  • the film formed using the adhesive for optical films of the present invention includes a dried product of the adhesive for optical films (that is, a dried product of an aqueous dispersion of a polyurethane resin composition).
  • a film can exhibit an adhesive function, for example, and can improve the adhesion to the base material, and can also improve the adhesion to the base material even in a high humidity and heat environment.
  • the adhesive for optical films of the present invention is suitable for use in optical films.
  • the method of forming the film is not particularly limited, and for example, the film can be formed by a known method. For example, by coating the surface of a substrate such as an optical film with an adhesive for optical films and volatilizing the aqueous solvent by drying, etc., a dried polyurethane resin aqueous dispersion is formed. can do.
  • the thickness of the film is not particularly limited, and can be adjusted to an appropriate thickness depending on the use and purpose.
  • optical film is not particularly limited, and for example, a wide variety of known optical films can be mentioned.
  • Optical films include polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; cyclic polyolefin resins; cellulose acetate resins such as triacetylcellulose and diacetylcellulose; polycarbonate resins; acrylics.
  • polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate
  • cyclic polyolefin resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate
  • cyclic polyolefin resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate
  • cyclic polyolefin resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene
  • the optical film can be provided with the film (film formed from the adhesive for optical films of the present invention) as an adhesive layer.
  • the method for forming a film on an optical film is not particularly limited either, and for example, a film can be formed on an optical film by coating the optical film with an adhesive for optical film. By bonding other members to such a film (adhesive layer), a laminate including an optical film can be obtained. Examples of other members include ultraviolet curing resins described later.
  • the adhesive for optical film of the present invention preferably bonds the optical film and an ultraviolet curing resin, for example.
  • the ultraviolet curable resin is not particularly limited, and examples thereof include acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, and epoxy resins.
  • the ultraviolet curable resin can be formed into, for example, a plate shape, a film shape, or the like.
  • the optical film is preferably polyethylene terephthalate.
  • An optical film having the film as an adhesive layer has high adhesion between the base material (optical film) and the film even under a high humidity and heat environment. Furthermore, even if another base material (for example, a PET base material) is bonded to the adhesive layer of such an optical film, the other base material can be bonded more firmly, and it can be used in a high humidity and heat environment. It can be firmly bonded even at the bottom.
  • another base material for example, a PET base material
  • a polyurethane resin aqueous dispersion was prepared by selecting an appropriate raw material from the following raw materials.
  • Polyester polyol (a-1), polyester polyol (a-2), and polyester polyol (a-3) were manufactured according to the recipe shown in Table 1 below.
  • Terephthalic acid, adipic acid, neopentyl glycol, and ethylene glycol were placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank, and a nitrogen gas introduction tube according to the formulation shown in Table 1, and the mixture was stirred under a nitrogen stream. The temperature was raised to 250°C.
  • polyester polyol (a-1), polyester polyol (a-2), and polyester polyol ( A solution of a-3) was obtained.
  • a polyurethane resin aqueous dispersion was prepared according to the following procedure.
  • the unit is "parts by mass", and a blank column means that the raw material is not used (ie, "0").
  • Example 1 Polyol (A) consisting of 81.45 parts by mass of polyester polyol (a-1) and 2.63 parts by mass of dimethylolpropionic acid (b), and 15.92 parts by mass of polyisocyanate (B) consisting of MDI. and 100 parts by mass of methyl ethyl ketone were mixed and reacted at 70 to 75°C for 120 minutes to obtain a urethane prepolymer solution.
  • This urethane prepolymer solution was cooled to 35°C, neutralized by adding 0.11 parts by mass of dibutylamine as a blocking agent and 1.88 parts by mass of triethylamine as a neutralizing agent, and then water was gradually added.
  • the mixture was emulsified and dispersed using a homogenizer. Thereafter, methyl ethyl ketone was distilled off to obtain an aqueous dispersion containing a polyurethane resin having a weight average molecular weight of 30,800 and an acid value of 11, as shown in Table 2.
  • Example 2 An aqueous dispersion containing a polyurethane resin was obtained in the same manner as in Example 1, except that the types and amounts of raw materials used were changed as shown in Table 2.
  • Comparative Examples 1 to 6 An aqueous dispersion containing a polyurethane resin was obtained in the same manner as in Example 1, except that the types and amounts of raw materials used were changed as shown in Table 2. In Comparative Example 6, the acid value was too small to emulsify and disperse, making it impossible to obtain an aqueous dispersion containing the desired polyurethane resin.
  • PET ⁇ Initial adhesion
  • the adhesion between the polyurethane resin adhesive and PET was evaluated by the following method.
  • the base material polyethylene terephthalate (PET) ("Lumirror T-60", manufactured by Toray Industries, Inc.)
  • PET polyethylene terephthalate
  • isopropyl alcohol was degreased with isopropyl alcohol, and then an aqueous dispersion containing polyurethane resin was applied with a bar coater to a dry film thickness of 10 ⁇ m.
  • the sample was dried at 80° C. for 10 minutes and then at 120° C. for 10 minutes to obtain a test piece A coated with a polyurethane resin adhesive (film).
  • Adhesion (%) 100 - (number of peeled squares) The case where the adhesion was 95% or more was determined to be a pass.
  • ⁇ Adhesion with three layers stacked> The adhesion between the polyurethane resin adhesive and PET in a three-layered state was evaluated by the following method.
  • a UV curable resin formulation solution was applied with a bar coater to a dry film thickness of 7 ⁇ m, dried at 80° C. for 1 minute, the solvent was removed, and then the UV curable resin was coated with the polyurethane resin adhesive.
  • a test piece B was obtained by irradiating the surface coated with the prescription liquid with ultraviolet rays of 600 mJ/cm 2 using a high-pressure mercury lamp.
  • the UV curing resin formulation liquid used 30 parts by mass of methyl ethyl ketone, 68 parts by mass of epoxy acrylate (GX-8821L-M9, manufactured by Daiichi Kogyo Seiyaku), and 2 parts by mass of a photopolymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals).
  • Adhesion (%) 100 - (separated squares) number) It was calculated by , and the case where the adhesion was 70% or more was considered to be a pass.
  • Adhesion (%) 100 - (number of peeled squares) It was calculated by , and the case where the adhesion was 50% or more was considered to be a pass.
  • Table 2 shows the compounding conditions adopted in producing the polyurethane resin aqueous dispersions prepared in each Example and Comparative Example and the evaluation results of the adhesives obtained from these polyurethane resin aqueous dispersions.
  • the unit of the acid value of the polyurethane resin is mgKOH/g.
  • the polyurethane resin aqueous dispersion obtained in the example can form an adhesive with excellent adhesion to the base material (PET film), even under a high humidity and heat environment. It was also found that adhesives with excellent adhesion to substrates can be formed. In addition, the polyurethane resin aqueous dispersion obtained in the example had adhesion with the base material (PET film) and ultraviolet rays because the adhesion of the three layers was at an acceptable level even in a high humidity and heat environment. It was also found that it could be strongly bonded to cured resin. In Comparative Example 4, since the total amount of bifunctional components was less than 98% by mass based on the polyurethane resin, the adhesiveness with the base material decreased in a high humidity and heat environment.

Abstract

Provided is an adhesive for an optical film with which it is possible increase adhesion to a substrate, even in a high-temperature, high-humidity environment.　This adhesive for an optical film contains an aqueous dispersion comprising a polyurethane resin (X). The polyurethane resin (X) has at least a structural unit derived from a polyol (A), and a structural unit derived from a polyisocyanate (B). The polyol (A) comprises a polyester polyol (a) having a structure derived from terephthalic acid and a structure derived from neopentyl glycol, and dimethylol propionic acid (b). The polyol (A) comprises at least 85 mass% of the polyester polyol (a). The weight average molecular weight of the polyurethane resin (X) is 5,000-50,000. The polyurethane resin (X) contains at least 98 mass% of a difunctional constituent component. The polyurethane resin (X) has an acid value of 5-15 mg KOH/g.

Description

光学フィルム用接着剤、皮膜及び光学フィルムAdhesives, films and optical films for optical films
　本発明は、光学フィルム用接着剤、皮膜及び光学フィルムに関する。 The present invention relates to adhesives for optical films, coatings, and optical films.
　ポリウレタン樹脂水分散体は、機械的性質、耐溶剤性、耐水性に優れる塗膜を形成することができることから、各種分野において、水性コーティング剤や接着剤等の幅広い分野で使用されている。この観点から、分散性を向上させたポリウレタン樹脂水分散体や、接着剤として使用したときに皮膜に種々の機能を発現させることが可能なポリウレタン樹脂組成物の開発が盛んに進められている。 Polyurethane resin aqueous dispersions can form coating films with excellent mechanical properties, solvent resistance, and water resistance, so they are used in a wide range of fields such as water-based coating agents and adhesives. From this point of view, the development of polyurethane resin aqueous dispersions with improved dispersibility and polyurethane resin compositions that can exhibit various functions in films when used as adhesives is actively underway.
　例えば、特許文献１には、ヒドロキシル基及び／又はカルボキシル基末端のフルオロポリエーテルと、ポリイソシアネートとを含む原料を水中で反応させることで、ポリウレタン樹脂水性分散体を製造する技術が開示されている。このように得られるポリウレタン樹脂水性分散体により、撥水、撥油性、防汚性だけでなく、耐ブロッキング性、表面滑性に優れる皮膜を形成できるものとされている。 For example, Patent Document 1 discloses a technique for producing an aqueous polyurethane resin dispersion by reacting raw materials containing a hydroxyl- and/or carboxyl-terminated fluoropolyether and a polyisocyanate in water. . The aqueous polyurethane resin dispersion thus obtained is said to be capable of forming a film that has not only water repellency, oil repellency, and stain resistance, but also excellent blocking resistance and surface smoothness.
特開平６－１４５５９８号公報Japanese Patent Application Publication No. 6-145598
　ポリウレタン樹脂水分散体は、例えば、光学フィルム等の各種分野において接着剤として広く利用されているところ、従来のポリウレタン樹脂水分散体を利用した接着剤では、基材との密着性が十分でないことがあり、改善の余地が残されていた。特に、従来のポリウレタン樹脂水分散体を利用した接着剤では、高湿熱環境下におかれたときの密着性が大きく低下することが問題となっていた。このような観点から、ポリウレタン樹脂水分散体を含む光学フィルム用接着剤では、高湿熱環境下であっても基材との密着性をより高める性能を有することが求められていた。 Polyurethane resin water dispersions are widely used as adhesives in various fields such as optical films, but conventional adhesives using polyurethane resin water dispersions do not have sufficient adhesion to substrates. However, there was still room for improvement. In particular, conventional adhesives using polyurethane resin water dispersions have a problem in that their adhesion is significantly reduced when placed in a high humidity and heat environment. From this point of view, there has been a demand for adhesives for optical films containing polyurethane resin aqueous dispersions to have the ability to further enhance adhesion to substrates even under high humidity and heat environments.
　本発明は、上記に鑑みてなされたものであり、高湿熱環境下であっても基材との密着性を高めることができる光学フィルム用接着剤、皮膜及び光学フィルムを提供することを目的とする。 The present invention has been made in view of the above, and aims to provide an adhesive for optical films, a coating, and an optical film that can improve adhesion to a substrate even in a high humidity and heat environment. do.
　本発明者らは、上記目的を達成すべく鋭意研究を重ねた結果、特定のポリオール由来の構造単位をポリウレタン樹脂に導入することにより上記目的を達成できることを見出し、本発明を完成するに至った。 As a result of intensive research to achieve the above object, the present inventors discovered that the above object could be achieved by introducing a structural unit derived from a specific polyol into a polyurethane resin, leading to the completion of the present invention. .
　すなわち、本発明は、例えば、以下の項に記載の主題を包含する。
項１
ポリウレタン樹脂（Ｘ）を含む水分散体を含有する光学フィルム用接着剤であって、
前記ポリウレタン樹脂（Ｘ）は、少なくともポリオール（Ａ）由来の構造単位と、ポリイソシアネート（Ｂ）由来の構造単位とを有し、
前記ポリオール（Ａ）は、テレフタル酸由来の構造とネオペンチルグリコール由来の構造とを有するポリエステルポリオール（ａ）、及び、ジメチロールプロピオン酸（ｂ）を含み、
前記ポリオール（Ａ）は、前記ポリエステルポリオール（ａ）を８５質量％以上含み、
前記ポリウレタン樹脂（Ｘ）の重量平均分子量は５０００～５００００であり、
前記ポリウレタン樹脂（Ｘ）は、２官能の構成成分を９８質量％以上含有し、
前記ポリウレタン樹脂（Ｘ）は、酸価が５～１５ｍｇＫＯＨ／ｇである、光学フィルム用接着剤。
項２
前記ポリイソシアネート（Ｂ）は、芳香族ポリイソシアネートを含む、項１に記載の光学フィルム用接着剤。
項３
項１又は２に記載の光学フィルム用接着剤の乾燥物を含む、皮膜。
項４
項３に記載の皮膜を接着層として備える、光学フィルム。 That is, the present invention includes, for example, the subject matter described in the following sections.
Item 1
An adhesive for optical films containing an aqueous dispersion containing a polyurethane resin (X),
The polyurethane resin (X) has at least a structural unit derived from the polyol (A) and a structural unit derived from the polyisocyanate (B),
The polyol (A) includes a polyester polyol (a) having a structure derived from terephthalic acid and a structure derived from neopentyl glycol, and dimethylolpropionic acid (b),
The polyol (A) contains 85% by mass or more of the polyester polyol (a),
The weight average molecular weight of the polyurethane resin (X) is 5000 to 50000,
The polyurethane resin (X) contains 98% by mass or more of a bifunctional component,
The polyurethane resin (X) is an adhesive for optical films, and has an acid value of 5 to 15 mgKOH/g.
Section 2
Item 2. The optical film adhesive according to Item 1, wherein the polyisocyanate (B) includes an aromatic polyisocyanate.
Section 3
Item 3. A film comprising a dried adhesive for optical films according to item 1 or 2.
Section 4
Item 3. An optical film comprising the film according to item 3 as an adhesive layer.
　本発明の光学フィルム用接着剤は、たとえ高湿熱環境下であっても基材との密着性を高めることができる。 The adhesive for optical films of the present invention can improve adhesion to a substrate even under a high humidity and heat environment.
　以下、本発明の実施形態について詳細に説明する。なお、本明細書中において、「含有」及び「含む」なる表現については、「含有」、「含む」、「実質的にからなる」及び「のみからなる」という概念を含む。 Hereinafter, embodiments of the present invention will be described in detail. Note that, in this specification, the expressions "contain" and "comprising" include the concepts of "containing", "containing", "consisting essentially of", and "consisting only".
　本発明の光学フィルム用接着剤は、ポリウレタン樹脂（Ｘ）を含む水分散体を含有する。前記ポリウレタン樹脂（Ｘ）は、少なくともポリオール（Ａ）由来の構造単位と、ポリイソシアネート（Ｂ）由来の構造単位とを有し、前記ポリオール（Ａ）は、テレフタル酸由来の構造とネオペンチルグリコール由来の構造とを有するポリエステルポリオール（ａ）、及び、ジメチロールプロピオン酸（ｂ）を含む。前記ポリオール（Ａ）は、前記ポリエステルポリオール（ａ）を８５質量％以上含み、前記ポリウレタン樹脂（Ｘ）の重量平均分子量は５０００～５００００であり、前記ポリウレタン樹脂（Ｘ）は、２官能の構成成分を９８質量％以上含有し、前記ポリウレタン樹脂（Ｘ）は、酸価が５～１５ｍｇＫＯＨ／ｇである。なお、「前記ポリウレタン樹脂（Ｘ）は、２官能の構成成分を９８質量％以上含有し、」とは、「前記ポリウレタン樹脂（Ｘ）は、２官能型化合物に由来する構成単位を９８質量％以上含有し、」と読み替えることができる。 The adhesive for optical films of the present invention contains an aqueous dispersion containing a polyurethane resin (X). The polyurethane resin (X) has at least a structural unit derived from polyol (A) and a structural unit derived from polyisocyanate (B), and the polyol (A) has a structure derived from terephthalic acid and a structure derived from neopentyl glycol. and dimethylolpropionic acid (b). The polyol (A) contains 85% by mass or more of the polyester polyol (a), the weight average molecular weight of the polyurethane resin (X) is 5,000 to 50,000, and the polyurethane resin (X) is a bifunctional component. The polyurethane resin (X) has an acid value of 5 to 15 mgKOH/g. Note that "the polyurethane resin (X) contains 98% by mass or more of a bifunctional component," means "the polyurethane resin (X) contains 98% by mass of structural units derived from a bifunctional compound." It can be read as "containing or more."
　本発明の光学フィルム用接着剤は前記ポリウレタン樹脂（Ｘ）を含むので、基材との密着性に優れる接着剤を形成することができ、しかも、たとえ高湿熱環境下であっても基材との密着性に優れる接着剤を形成することができる。 Since the adhesive for optical films of the present invention contains the polyurethane resin (X), it is possible to form an adhesive that has excellent adhesion to the base material, and even in a high humidity and heat environment. It is possible to form an adhesive with excellent adhesion.
　以下、本発明の光学フィルム用接着剤に含まれるポリウレタン樹脂（Ｘ）を含む水分散体（ポリウレタン樹脂水分散体）の構成について詳述する。 Hereinafter, the structure of the aqueous dispersion (polyurethane resin aqueous dispersion) containing the polyurethane resin (X) contained in the adhesive for optical films of the present invention will be described in detail.
　（ポリオール（Ａ））
　ポリウレタン樹脂（Ｘ）は、少なくともポリオール（Ａ）由来の構造単位を有する。 (Polyol (A))
The polyurethane resin (X) has at least a structural unit derived from the polyol (A).
　本発明では、ポリオール（Ａ）は、複数の水酸基を有する化合物（好ましくは、２個の水酸基を有する化合物）を少なくとも２種以上含有する組成物である。特に本発明では、ポリオール（Ａ）は、テレフタル酸由来の構造とネオペンチルグリコール由来の構造とを有するポリエステルポリオール（ａ）、及び、ジメチロールプロピオン酸（ｂ）を少なくとも含む。これにより、本発明の光学フィルム用接着剤は、高湿熱環境下であっても基材との密着性に優れる接着剤を形成することができる。念のための注記であるが、ジメチロールプロピオン酸（ｂ）は、水酸基を２個有する化合物であるので、斯かる化合物は２官能の化合物である。 In the present invention, the polyol (A) is a composition containing at least two kinds of compounds having multiple hydroxyl groups (preferably, compounds having two hydroxyl groups). In particular, in the present invention, the polyol (A) includes at least a polyester polyol (a) having a structure derived from terephthalic acid and a structure derived from neopentyl glycol, and dimethylolpropionic acid (b). As a result, the adhesive for optical films of the present invention can form an adhesive that has excellent adhesion to a base material even under a high humidity and heat environment. As a precautionary note, since dimethylolpropionic acid (b) is a compound having two hydroxyl groups, such a compound is a bifunctional compound.
　ポリエステルポリオール（ａ）は、例えば、グリコール化合物と、カルボキシ基含有化合物との脱水縮合反応によって形成される化合物であり、グリコール由来の構造と、カルボキシ基含有化合物由来の構造とを有する。従って、本発明では、ポリエステルポリオール（ａ）は、例えば、ネオペンチルグリコールを含むグリコールと、テレフタル酸を含むカルボキシ基含有化合物との脱水縮合反応によって形成され得るポリエステルポリオール化合物である。 The polyester polyol (a) is, for example, a compound formed by a dehydration condensation reaction between a glycol compound and a carboxyl group-containing compound, and has a structure derived from glycol and a structure derived from the carboxyl group-containing compound. Therefore, in the present invention, the polyester polyol (a) is a polyester polyol compound that can be formed, for example, by a dehydration condensation reaction of a glycol including neopentyl glycol and a carboxyl group-containing compound including terephthalic acid.
　ポリエステルポリオール（ａ）は、本発明の効果が阻害されない限り、テレフタル酸由来の構造及びネオペンチルグリコール由来の構造以外に他の化合物に由来する構造を含むことができる。斯かる他の化合物は、例えば、公知のポリエステルポリオールを製造するために使用される化合物を広く挙げることができ、例えば、イソフタル酸、アジピン酸、コハク酸、アゼライン酸、セバシン酸、ドデカンジカルボン酸、無水マレイン酸、フマル酸、１，３－シクロペンタンジカルボン酸、１，４－シクロヘキサンジカルボン酸、フタル酸、１，４－ナフタレンジカルボン酸、２，５－ナフタレンジカルボン酸、２，６－ナフタレンジカルボン酸、ナフタル酸、ビフェニルジカルボン酸、１，２－ビス（フェノキシ）エタン－ｐ，ｐ´－ジカルボン酸等のカルボキシ基含有化合物；当該カルボキシ基含有化合物の無水物；エチレングリコール、プロピレングリコール、１，３－プロパンジオール、１，４－ブタンジオール、１，５－ペンタンジオール、３－メチル－１，５－ペンタンジオール、１，６－ヘキサンジオール、ジエチレングリコール、トリエチレングリコール、テトラエチレングリコール、分子量６０００以下のポリエチレングリコール、ジプロピレングリコール、トリプロピレングリコール、ビスヒドロキシエトキシベンゼン、１，４－シクロヘキサンジオール、１，４－シクロヘキサンジメタノール、ビスフェノールＡ、水素添加ビスフェノールＡ、ハイドロキノン等のグリコール成分が挙げられる。 The polyester polyol (a) can contain a structure derived from another compound in addition to the structure derived from terephthalic acid and the structure derived from neopentyl glycol, as long as the effects of the present invention are not impaired. Such other compounds can include, for example, a wide range of compounds used for producing known polyester polyols, such as isophthalic acid, adipic acid, succinic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, Maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid , naphthalic acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid, and other carboxy group-containing compounds; anhydrides of the carboxy group-containing compounds; ethylene glycol, propylene glycol, 1,3 -Propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, with a molecular weight of 6000 or less Examples of glycol components include polyethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A, and hydroquinone.
　これらの中でも、ポリエステルポリオール（ａ）は、アジピン酸及びエチレングリコールからなる群より選ばれる少なくとも１種の化合物に由来する構造をさらに有することが好ましい。この場合、本発明の光学フィルム用接着剤は、高湿熱環境下であっても基材との密着性を高めることができる。 Among these, it is preferable that the polyester polyol (a) further has a structure derived from at least one compound selected from the group consisting of adipic acid and ethylene glycol. In this case, the adhesive for optical films of the present invention can improve adhesion to the substrate even under a high humidity and heat environment.
　ポリエステルポリオール（ａ）において、テレフタル酸由来の構造及びネオペンチルグリコール由来の構造の含有割合は特に限定されない。例えば、ポリエステルポリオール（ａ）の全構造単位に対し、テレフタル酸由来の構造の含有割合は１０～７０質量％であることが好ましく、１０～６０質量％であることがより好ましく、１５～４５質量％であることがさらに好ましい。また、ポリエステルポリオール（ａ）の全構造単位に対し、ネオペンチルグリコール由来の構造の含有割合は２０～６０質量％であることが好ましく、３０～５５質量％であることがより好ましい。 In the polyester polyol (a), the content ratio of the structure derived from terephthalic acid and the structure derived from neopentyl glycol is not particularly limited. For example, the content of the structure derived from terephthalic acid is preferably 10 to 70% by mass, more preferably 10 to 60% by mass, and 15 to 45% by mass with respect to the total structural units of the polyester polyol (a). % is more preferable. Furthermore, the content of the structure derived from neopentyl glycol is preferably 20 to 60% by mass, more preferably 30 to 55% by mass, based on the total structural units of the polyester polyol (a).
　ポリエステルポリオール（ａ）がテレフタル酸由来の構造及びネオペンチルグリコール由来の構造以外に他の化合物に由来する構造を含む場合、他の化合物に由来する構造の含有割合は特に限定されない。例えば、ポリエステルポリオール（ａ）の全構造単位に対し、他の化合物に由来する構造の含有割合は５～５０質量％であることが好ましく、７～４８質量％であることがより好ましく、１０～４５質量％であることがさらに好ましい。言い換えれば、ポリエステルポリオール（ａ）の全構造単位に対し、テレフタル酸由来の構造及びネオペンチルグリコール由来の構造の含有割合は５０～９５質量％であることが好ましく、５２～９３質量％であることがより好ましく、５５～９０質量％であることがさらに好ましい。 When the polyester polyol (a) contains a structure derived from another compound in addition to the structure derived from terephthalic acid and the structure derived from neopentyl glycol, the content ratio of the structure derived from the other compound is not particularly limited. For example, the content of structures derived from other compounds is preferably 5 to 50% by mass, more preferably 7 to 48% by mass, and 10 to 48% by mass, based on the total structural units of polyester polyol (a). More preferably, it is 45% by mass. In other words, the content of the structure derived from terephthalic acid and the structure derived from neopentyl glycol is preferably 50 to 95% by mass, and preferably 52 to 93% by mass, based on the total structural units of the polyester polyol (a). is more preferable, and even more preferably 55 to 90% by mass.
　また、ポリエステルポリオール（ａ）がテレフタル酸及びアジピン酸からなる群より選ばれる少なくとも１種のカルボン酸化合物に由来する構造を有する場合、これらの構造の含有割合は特に限定されず、例えば、ポリエステルポリオール（ａ）の全構造単位に対し、７０質量％以下であることが好ましく、６０質量％以下であることがより好ましい。 Further, when the polyester polyol (a) has a structure derived from at least one carboxylic acid compound selected from the group consisting of terephthalic acid and adipic acid, the content ratio of these structures is not particularly limited, and for example, the polyester polyol It is preferably 70% by mass or less, more preferably 60% by mass or less, based on the total structural units of (a).
　また、ポリエステルポリオール（ａ）がエチレングリコールに由来する構造を有する場合、斯かる構造の含有割合は特に限定されず、例えば、ポリエステルポリオール（ａ）の全構造単位に対し、５質量％以下であることが好ましく、３質量％以下であることがより好ましい。 In addition, when the polyester polyol (a) has a structure derived from ethylene glycol, the content of such a structure is not particularly limited, and is, for example, 5% by mass or less based on the total structural units of the polyester polyol (a). The content is preferably 3% by mass or less, and more preferably 3% by mass or less.
　ポリエステルポリオール（ａ）は、２官能のポリエステルポリオールを９８質量％以上含有することが好ましく、９９質量％以上含有することがより好ましい。これらの場合において、残部は、例えば、３官能以上のポリエステルポリオールであり得る。ポリエステルポリオール（ａ）は、２官能のポリエステルポリオールのみからなるものであってもよい。 The polyester polyol (a) preferably contains 98% by mass or more, more preferably 99% by mass or more of a bifunctional polyester polyol. In these cases, the remainder may be, for example, a trifunctional or higher functional polyester polyol. The polyester polyol (a) may consist only of a bifunctional polyester polyol.
　ポリエステルポリオール（ａ）の数平均分子量は、特に限定されず、例えば、５００以上が好ましく、１０００以上がより好ましく、１５００以上がさらに好ましく、また、５０００以下が好ましく、４０００以下がより好ましく、３０００以下がさらに好ましい。 The number average molecular weight of the polyester polyol (a) is not particularly limited, for example, preferably 500 or more, more preferably 1000 or more, even more preferably 1500 or more, and preferably 5000 or less, more preferably 4000 or less, 3000 or less. is even more preferable.
　ポリオール（Ａ）に含まれる、ポリエステルポリオール（ａ）は、１種単独であってもよいし、２種以上であってもよい。 The polyester polyol (a) contained in the polyol (A) may be used alone or in combination of two or more.
　ポリエステルポリオール（ａ）は、例えば、公知の製造方法と同様の方法で得ることができ、あるいは、市販品等から入手することもできる。例えば、前述のように、ポリエステルポリオール（ａ）は、グリコール化合物と、カルボキシ基含有化合物との脱水縮合反応によって製造できる。 The polyester polyol (a) can be obtained, for example, by a method similar to a known manufacturing method, or can be obtained from a commercially available product. For example, as described above, polyester polyol (a) can be produced by a dehydration condensation reaction between a glycol compound and a carboxyl group-containing compound.
　ポリオール（Ａ）は、前記ポリエステルポリオール（ａ）、及び、ジメチロールプロピオン酸（ｂ）以外に他のポリオール化合物を含むこともできる。他のポリオール化合物は、公知のポリオールを広く挙げることができ、例えば、ポリエステルポリオール（ａ）以外のポリエステルポリオール化合物、ポリカーボネートポリオール、ポリエーテルポリオール、炭化水素系ポリオール、又は分子量４００以下の低分子量ポリオール、ジメチロールプロピオン酸（ｂ）以外の活性水素基とカルボキシ基（又はその塩）を各１個以上含有する化合物等を挙げることができる。 The polyol (A) can also contain other polyol compounds in addition to the polyester polyol (a) and dimethylolpropionic acid (b). Other polyol compounds can include a wide range of known polyols, such as polyester polyol compounds other than polyester polyol (a), polycarbonate polyols, polyether polyols, hydrocarbon polyols, or low molecular weight polyols with a molecular weight of 400 or less, Compounds containing at least one active hydrogen group and one or more carboxy groups (or salts thereof) other than dimethylolpropionic acid (b) can be mentioned.
　ポリカーボネートポリオールは特に限定されず、例えば、ウレタン樹脂を形成するための公知のポリカーボネートポリオールを広く挙げることができる。例えば、ポリカーボネートポリオールとして、１，４－ブタンジオール、１，６－ヘキサンジオール、ジエチレングリコール等のグリコールとジフェニルカーボネート、ホスゲンとの反応によって得られる化合物が挙げられる。ポリカーボネートポリオールは、例えば、公知の製造方法と同様の方法で得ることができ、あるいは、市販品等から入手することもできる。 The polycarbonate polyol is not particularly limited, and for example, a wide range of known polycarbonate polyols for forming urethane resins can be mentioned. Examples of polycarbonate polyols include compounds obtained by reacting glycols such as 1,4-butanediol, 1,6-hexanediol, and diethylene glycol with diphenyl carbonate and phosgene. Polycarbonate polyol can be obtained, for example, by a method similar to a known manufacturing method, or can be obtained from a commercially available product.
　ポリエーテルポリオールは特に限定されず、例えば、ウレタン樹脂を形成するための公知のポリエーテルポリオールを広く挙げることができる。例えば、ポリオール化合物とアルキレンオキサイドとを付加重合させてなるポリエーテルポリオールが挙げられる。ポリエステルポリオールを形成するためのポリオール化合物は、各種の脂肪族ポリオール、脂環式ポリオールが挙げられる。アルキレンオキサイドとしては、例えば、エチレンオキサイド、プロピレンオキサイド、ブチレンオキサイド等のアルキレンオキサイド等が挙げられる。ポリエーテルポリオールは、例えば、公知の製造方法と同様の方法で得ることができ、あるいは、市販品等から入手することもできる。市販品としては、例えば、三洋化成社の「ニューポールＢＰＥ」（登録商標）シリーズを挙げることができる。 The polyether polyol is not particularly limited, and for example, a wide range of known polyether polyols for forming urethane resins can be mentioned. For example, a polyether polyol formed by addition polymerizing a polyol compound and an alkylene oxide can be mentioned. Examples of the polyol compound for forming the polyester polyol include various aliphatic polyols and alicyclic polyols. Examples of the alkylene oxide include alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide. The polyether polyol can be obtained, for example, by a method similar to a known manufacturing method, or can be obtained from a commercially available product. Commercially available products include, for example, the "Newport BPE" (registered trademark) series manufactured by Sanyo Chemical Co., Ltd.
　炭化水素系ポリオールは特に限定されず、例えば、ウレタン樹脂を形成するための公知の炭化水素系ポリオールを広く挙げることができる。例えば、炭化水素系ポリオールとしては、炭化水素鎖の末端を水酸基で終端したもので、例えば、ポリブタジエンポリオール、ポリイソプレンポリオール、水添ポリブタジエンポリオール、又は水添ポリイソプレンポリオール等を挙げることができる。 The hydrocarbon polyol is not particularly limited, and includes a wide range of known hydrocarbon polyols for forming urethane resins. For example, the hydrocarbon polyol has a hydrocarbon chain terminated with a hydroxyl group, such as polybutadiene polyol, polyisoprene polyol, hydrogenated polybutadiene polyol, or hydrogenated polyisoprene polyol.
　分子量が４００以下の低分子量ポリオールは、例えば、エチレングリコール、ジエチレングリコール、トリエチレングリコール、１，２－プロピレングリコール、１ ，３－プロピレングリコール、ネオペンチルグリコール、１，３－ブタンジオール、１，４－ブタンジオール、３－メチルペンタンジオール（ＭＰＤ）、１，６－ヘキサンジオール（１，６－ＨＤ）、１，８－オクタンジオール、２－メチル－１，３－プロパンジオール、ビスフェノールＡ、水添ビスフェノールＡ、シクロヘキサンジメタノール、グリセリン、トリメチロールプロパン等が挙げられる。 Examples of low molecular weight polyols having a molecular weight of 400 or less include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, neopentyl glycol, 1,3-butanediol, and 1,4-propylene glycol. Butanediol, 3-methylpentanediol (MPD), 1,6-hexanediol (1,6-HD), 1,8-octanediol, 2-methyl-1,3-propanediol, bisphenol A, hydrogenated bisphenol A, cyclohexanedimethanol, glycerin, trimethylolpropane and the like.
　活性水素基とカルボキシ基（又はその塩）を各１個以上含有する化合物（ジメチロールプロピオン酸（ｂ）を除く）は、例えば、２，２－ジメチロール酪酸、２，２－ジメチロール吉草酸、ジオキシマレイン酸、２，６－ジオキシ安息香酸、３，４－ジアミノ安息香酸等のカルボン酸含有化合物及びこれらの誘導体並びにそれらの塩が挙げられ。その他、活性水素基とカルボキシ基（又はその塩）を各１個以上含有する化合物としては、アラニン、アミノ酪酸、アミノカプロン酸、グリシン、グルタミン酸、アスパラギン酸、ヒスチジン等のアミノ酸類、コハク酸、アジピン酸、無水マレイン酸、フタル酸、無水トリメリット酸等のカルボン酸類も挙げられる。 Compounds containing at least one active hydrogen group and one or more carboxyl groups (or their salts) (excluding dimethylolpropionic acid (b)) are, for example, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, dimethylolpropionic acid (b), etc. Examples include carboxylic acid-containing compounds such as oxymaleic acid, 2,6-dioxybenzoic acid, 3,4-diaminobenzoic acid, derivatives thereof, and salts thereof. Other compounds containing at least one active hydrogen group and one or more carboxyl groups (or their salts) include amino acids such as alanine, aminobutyric acid, aminocaproic acid, glycine, glutamic acid, aspartic acid, and histidine, succinic acid, and adipic acid. , maleic anhydride, phthalic acid, trimellitic anhydride, and other carboxylic acids.
　ポリオール（Ａ）は、ポリエステルポリオール（ａ）を８５質量％以上含む。すなわち、ポリオール（Ａ）の総質量に対し、ポリエステルポリオール（ａ）の含有割合が８５質量％以上である。これにより、本発明の光学フィルム用接着剤は、高湿熱環境下であっても基材との密着性に優れる接着剤を形成することができる。ポリオール（Ａ）の総質量に対し、ポリエステルポリオール（ａ）の含有割合が８５質量％未満である場合、高湿熱環境下における基材との密着性が低下する。ポリオール（Ａ）は、２官能のポリエステルポリオール（ａ）を８５質量％以上含むことがより好ましい。 The polyol (A) contains 85% by mass or more of the polyester polyol (a). That is, the content of the polyester polyol (a) is 85% by mass or more based on the total mass of the polyol (A). As a result, the adhesive for optical films of the present invention can form an adhesive that has excellent adhesion to a base material even under a high humidity and heat environment. When the content of the polyester polyol (a) is less than 85% by mass with respect to the total mass of the polyol (A), the adhesion to the base material in a high humidity and heat environment decreases. It is more preferable that the polyol (A) contains 85% by mass or more of the bifunctional polyester polyol (a).
　ここで、ポリオール（Ａ）の総質量とは、ポリエステルポリオール（ａ）、及びジメチロールプロピオン酸（ｂ）、並びにその他のポリオール化合物（水酸基を２以上有する化合物）の総質量を意味する。 Here, the total mass of polyol (A) means the total mass of polyester polyol (a), dimethylolpropionic acid (b), and other polyol compounds (compounds having two or more hydroxyl groups).
　ポリオール（Ａ）は、ポリエステルポリオール（ａ）（好ましくは２官能のポリエステルポリオール（ａ））を８７質量％以上含むことが好ましく、９０質量％以上含むことがより好ましく、９２質量％以上含むことがさらに好ましく、９５質量％以上含むことが特に好ましい。ポリオール（Ａ）は、ポリエステルポリオール（ａ）（好ましくは２官能のポリエステルポリオール（ａ））を９９質量％以下含むことが好ましく、９７質量％以下含むことがより好ましい。 The polyol (A) preferably contains 87% by mass or more, more preferably 90% by mass or more, and preferably 92% by mass or more of polyester polyol (a) (preferably bifunctional polyester polyol (a)). More preferably, it is particularly preferably contained in an amount of 95% by mass or more. The polyol (A) preferably contains 99% by mass or less, more preferably 97% by mass or less of polyester polyol (a) (preferably bifunctional polyester polyol (a)).
　ジメチロールプロピオン酸（ｂ）の含有量は、ポリエステルポリオール（ａ）の総質量１００質量部あたり、１～１０質量部であることが好ましく、２～８質量部であることがより好ましく、２．５～７質量部であることがさらに好ましく、３～６質量部であることが特に好ましい。なお、ジメチロールプロピオン酸は、「２，２－ジメチロールプロピオン酸」ともいう。 The content of dimethylolpropionic acid (b) is preferably 1 to 10 parts by mass, more preferably 2 to 8 parts by mass, per 100 parts by mass of the total mass of polyester polyol (a). It is more preferably 5 to 7 parts by weight, particularly preferably 3 to 6 parts by weight. Note that dimethylolpropionic acid is also referred to as "2,2-dimethylolpropionic acid."
　ポリオール（Ａ）は、３官能以上の低鎖ポリオールを含むこともできるが、この含有割合は、ポリオール（Ａ）の全質量に対し、０．７５質量％以下であることが好ましく、０．４０質量％以下であることがより好ましく、０．３０質量％以下であることがさらに好ましくい。これにより、本発明の光学フィルム用接着剤は、高湿熱環境下であっても基材との密着性により優れるものとなる。３官能以上の低鎖ポリオール化合物としては、例えば、分子量が１５０以下の多価アルコールを挙げることができ、具体的にトリメチロールプロパン、ペンタエリスリトールが挙げられる。ポリオール（Ａ）は、３官能以上の低鎖ポリオールを含まなくてもよい。 The polyol (A) can also contain a trifunctional or higher-functional low chain polyol, but this content is preferably 0.75% by mass or less, and 0.40% by mass or less based on the total mass of the polyol (A). It is more preferably at most 0.30% by mass, even more preferably at most 0.30% by mass. As a result, the adhesive for optical films of the present invention has excellent adhesion to the substrate even under a high humidity and heat environment. Examples of trifunctional or higher-functional low-chain polyol compounds include polyhydric alcohols with a molecular weight of 150 or less, and specific examples include trimethylolpropane and pentaerythritol. The polyol (A) does not need to contain a trifunctional or higher-functional low chain polyol.
　ポリオール（Ａ）は、２官能のポリオール（すなわち、水酸基を２個有するポリオール）を９８質量％以上含有することが好ましく、９９質量％以上含有することがより好ましい。これらの場合において、残部は、例えば、３官能以上のポリオールであり得る。ポリオール（Ａ）は、２官能のポリオールのみからなるものであってもよい。 The polyol (A) preferably contains 98% by mass or more, more preferably 99% by mass or more of a bifunctional polyol (that is, a polyol having two hydroxyl groups). In these cases, the remainder may be, for example, a trifunctional or higher functional polyol. The polyol (A) may consist only of a bifunctional polyol.
　（ポリイソシアネート（Ｂ））
　ポリウレタン樹脂（Ｘ）は、ポリイソシアネート（Ｂ）由来の構造単位を有する。ポリイソシアネート（Ｂ）は特に限定されず、例えば、ポリウレタン樹脂を形成するために使用されるポリイソシアネート化合物を広く挙げることができ、例えば、２個以上のイソシアネート基を有する化合物を挙げることができ、２個のイソシアネート基を有する化合物であることがより好ましい。 (Polyisocyanate (B))
The polyurethane resin (X) has a structural unit derived from the polyisocyanate (B). The polyisocyanate (B) is not particularly limited, and can include a wide range of polyisocyanate compounds used for forming polyurethane resins, such as compounds having two or more isocyanate groups, A compound having two isocyanate groups is more preferred.
　ポリイソシアネート（Ｂ）としては、具体的に、脂肪族ジイソシアネート、脂環族ジイソシアネート、芳香族ジイソシアネート、芳香脂肪族ジイソシアネート等の２官能型イソシアネート化合物を挙げることができる。 Specific examples of the polyisocyanate (B) include bifunctional isocyanate compounds such as aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, and araliphatic diisocyanates.
　脂肪族ポリイソシアネートとしては、例えば、テトラメチレンジイソシアネート、ドデカメチレンジイソシアネート、ヘキサメチレンジイソシアネート、２，２，４－トリメチルヘキサメチレンジイソシアネート、２，４，４－トリメチルヘキサメチレンジイソシアネート、リジンジイソシアネート、２－メチルペンタン－１，５－ジイソシアネート、３－メチルペンタン－１，５－ジイソシアネート等を挙げることができる。 Examples of aliphatic polyisocyanates include tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and 2-methylpentane. Examples include -1,5-diisocyanate and 3-methylpentane-1,5-diisocyanate.
　脂環族ポリイソシアネートとしては、例えば、イソホロンジイソシアネート、水素添加キシリレンジイソシアネート、４，４’－ジシクロヘキシルメタンジイソシアネート（以下、「Ｈ１２ＭＤＩ」と表記することができる）、１，４－シクロヘキサンジイソシアネート、メチルシクロヘキシレンジイソシアネート、１，３－ビス（イソシアネートメチル）シクロヘキサン等を挙げることができる。 Examples of the alicyclic polyisocyanate include isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate (hereinafter referred to as "H12MDI"), 1,4-cyclohexane diisocyanate, and methylcyclohexyl diisocyanate. Examples include silane diisocyanate and 1,3-bis(isocyanatemethyl)cyclohexane.
　芳香族ポリイソシアネートとしては、例えば、トリレンジイソシアネート、２，２’－ジフェニルメタンジイソシアネート、２，４’－ジフェニルメタンジイソシアネート、４，４’－ジフェニルメタンジイソシアネート、ポリメチレンポリフェニルポリイソシアネート、４，４’－ジベンジルジイソシアネート、１，５－ナフチレンジイソシアネート、キシリレンジイソシアネート、１，３－フェニレンジイソシアネート、１，４－フェニレンジイソシアネート等を挙げることができる。 Examples of aromatic polyisocyanates include tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, and 4,4'-diisocyanate. Examples include benzyl diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, and 1,4-phenylene diisocyanate.
　芳香脂肪族ポリイソシアネートとしては、例えば、ジアルキルジフェニルメタンジイソシアネート、テトラアルキルジフェニルメタンジイソシアネート、α，α，α，α－テトラメチルキシリレンジイソシアネート等を挙げることができる。 Examples of the aromatic aliphatic polyisocyanate include dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, α,α,α,α-tetramethylxylylene diisocyanate, and the like.
　また、ポリイソシアネート（Ｂ）として、有機ポリイソシアネートの変性体を用いてもよい。有機ポリイソシアネートの変性体としては、特に限定されず、例えば、カルボジイミド体、アロファネート体、ビューレット体、イソシアヌレート体、アダクト体等を挙げることができる。尚、ポリイソシアネートは、単独で又は２種以上を併用して用いることもできる。 Additionally, a modified organic polyisocyanate may be used as the polyisocyanate (B). The modified organic polyisocyanate is not particularly limited, and examples thereof include carbodiimide, allophanate, biuret, isocyanurate, and adduct. In addition, polyisocyanate can also be used individually or in combination of 2 or more types.
　ポリイソシアネート（Ｂ）の数平均分子量は、特に限定されないが、１００以上４００以下が好ましく、１２０以上３００以下がより好ましく、１５０以上２８０以下がより好ましい。 The number average molecular weight of the polyisocyanate (B) is not particularly limited, but is preferably 100 or more and 400 or less, more preferably 120 or more and 300 or less, and more preferably 150 or more and 280 or less.
　ポリイソシアネート（Ｂ）は、芳香族ポリイソシアネートであることが好ましく、２官能の芳香族ポリイソシアネートであることがより好ましい。芳香族ポリイソシアネートは、トリレンジイソシアネート（ＴＤＩ）、４，４’－ジフェニルメタンジイソシアネート（ＭＤＩ）であることが好ましい。 The polyisocyanate (B) is preferably an aromatic polyisocyanate, more preferably a bifunctional aromatic polyisocyanate. Preferably, the aromatic polyisocyanate is tolylene diisocyanate (TDI) or 4,4'-diphenylmethane diisocyanate (MDI).
　ポリイソシアネート（Ｂ）は、公知の製造方法で得ることができ、あるいは、市販品から入手することも可能である。ポリイソシアネートは、１種単独であってもよいし、２種以上を含むものであってもよい。 Polyisocyanate (B) can be obtained by a known production method or can be obtained from a commercially available product. The polyisocyanate may be used alone or in combination of two or more.
　ポリイソシアネート（Ｂ）は、２官能のイソシアネートを９８質量％以上含有することが好ましく、９９質量％以上含有することがより好ましい。これらの場合において、残部は、例えば、３官能以上のポリイソシアネートであり得る。ポリイソシアネート（Ｂ）は、２官能のポリオールのみからなるものであってもよい。 The polyisocyanate (B) preferably contains 98% by mass or more, more preferably 99% by mass or more of a bifunctional isocyanate. In these cases, the remainder may be, for example, a trifunctional or higher functional polyisocyanate. The polyisocyanate (B) may consist only of a difunctional polyol.
　（ポリウレタン樹脂（Ｘ））
　ポリウレタン樹脂（Ｘ）は、前記ポリオール（Ａ）由来の構造単位と、前記ポリイソシアネート（Ｂ）由来の構造単位とを有する。ポリウレタン樹脂（Ｘ）は、これらの構造単位の他、例えば、後記するブロック剤に由来する構造や鎖長伸長剤に由来する構造を含むこともできる。ポリウレタン樹脂（Ｘ）は、前記ポリオール（Ａ）由来の構造単位と、前記ポリイソシアネート（Ｂ）由来の構造単位のみで形成することもできる。 (Polyurethane resin (X))
The polyurethane resin (X) has a structural unit derived from the polyol (A) and a structural unit derived from the polyisocyanate (B). In addition to these structural units, the polyurethane resin (X) can also include, for example, a structure derived from a blocking agent or a structure derived from a chain extender, which will be described later. The polyurethane resin (X) can also be formed only from structural units derived from the polyol (A) and structural units derived from the polyisocyanate (B).
　ポリウレタン樹脂（Ｘ）は、後記する一官能の活性水素基を有する化合物由来の構造単位を有することもある。ポリウレタン樹脂（Ｘ）が一官能の活性水素基を有する化合物由来の構造単位を含む場合、その含有割合はポリウレタン樹脂（Ｘ）の全構造単位に対し、５質量％以下であることが好ましく、３質量％以下であることがより好ましく、１質量％以下であることがさらに好ましい。これにより、本発明の光学フィルム用接着剤は、高湿熱環境下であっても基材との密着性により優れる。 The polyurethane resin (X) may have a structural unit derived from a compound having a monofunctional active hydrogen group, which will be described later. When the polyurethane resin (X) contains a structural unit derived from a compound having a monofunctional active hydrogen group, the content thereof is preferably 5% by mass or less based on the total structural units of the polyurethane resin (X), and 3. It is more preferably at most 1% by mass, even more preferably at most 1% by mass. As a result, the adhesive for optical films of the present invention has excellent adhesion to the substrate even under a high humidity and heat environment.
　その他、ポリウレタン樹脂（Ｘ）は、後記する鎖長伸長剤として使用されるポリアミン（鎖長伸長剤）等の低鎖アミン化合物由来の構造単位を有することもある。 In addition, the polyurethane resin (X) may have a structural unit derived from a low-chain amine compound such as a polyamine (chain extender) used as a chain extender to be described later.
　ポリウレタン樹脂（Ｘ）において、各構造単位の含有割合は特に限定されない。例えば、ポリウレタン樹脂（Ｘ）は、ポリオール（Ａ）由来の構造単位及びポリイソシアネート（Ｂ）由来の構造単位の総質量１００質量に対し、ポリイソシアネート由来の構造単位を５～５０質量部含有することが好ましく、１０～４０質量部含有することがより好ましい。 In the polyurethane resin (X), the content ratio of each structural unit is not particularly limited. For example, the polyurethane resin (X) should contain 5 to 50 parts by mass of structural units derived from polyisocyanate based on 100 parts by mass of the total mass of structural units derived from polyol (A) and structural units derived from polyisocyanate (B). is preferred, and more preferably 10 to 40 parts by mass.
　ポリウレタン樹脂（Ｘ）は、２官能の構成成分（すなわち、２官能型化合物に由来する構成単位）を９８質量％以上含有する。これにより、本発明の光学フィルム用接着剤は、高湿熱環境下であっても基材との密着性により優れるものとなる。ポリウレタン樹脂（Ｘ）は、２官能の構成成分を９９質量％以上含むことが好ましい。ポリウレタン樹脂（Ｘ）は２官能の構成成分のみで形成されていてもよい。ここで、２官能の構成成分とは、例えば、２官能型のポリオール（Ａ）及び２官能型のポリイソシアネート（Ｂ）である。 The polyurethane resin (X) contains 98% by mass or more of a bifunctional component (that is, a structural unit derived from a bifunctional compound). As a result, the adhesive for optical films of the present invention has excellent adhesion to the substrate even under a high humidity and heat environment. It is preferable that the polyurethane resin (X) contains 99% by mass or more of a bifunctional component. The polyurethane resin (X) may be formed only from bifunctional components. Here, the bifunctional constituent components are, for example, a bifunctional polyol (A) and a bifunctional polyisocyanate (B).
　ポリウレタン樹脂（Ｘ）が３官能以上の化合物に由来する構造を有する場合、その含有割合は、ポリウレタン樹脂（Ｘ）の全質量に対して３質量％以下であることが好ましく、０．７５質量％以下であることがより好ましく、０．４０質量％以下であることがさらに好ましく、０．３０質量％以下であることが特に好ましい。 When the polyurethane resin (X) has a structure derived from a trifunctional or more functional compound, the content thereof is preferably 3% by mass or less with respect to the total mass of the polyurethane resin (X), and 0.75% by mass. It is more preferably at most 0.40% by mass, even more preferably at most 0.30% by mass.
　本発明において、ポリウレタン樹脂（Ｘ）の重量平均分子量は、５０００～５００００である。これにより、本発明の光学フィルム用接着剤は、高湿熱環境下であっても基材との密着性に優れる。ポリウレタン樹脂（Ｘ）の重量平均分子量が５０００未満の場合、本発明の光学フィルム用接着剤は、高湿熱環境下における基材との密着性が低下する。また、ポリウレタン樹脂（Ｘ）の重量平均分子量が５００００を上回ると、本発明の光学フィルム用接着剤は、高湿熱環境下における基材との密着性が低下する。 In the present invention, the weight average molecular weight of the polyurethane resin (X) is 5,000 to 50,000. As a result, the adhesive for optical films of the present invention has excellent adhesion to the substrate even under a high humidity and heat environment. When the weight average molecular weight of the polyurethane resin (X) is less than 5,000, the adhesive for optical films of the present invention has poor adhesion to the substrate in a high humidity and heat environment. In addition, when the weight average molecular weight of the polyurethane resin (X) exceeds 50,000, the adhesive for optical films of the present invention has poor adhesion to the substrate in a high humidity and heat environment.
　ポリウレタン樹脂（Ｘ）の重量平均分子量は、Ｎ，Ｎ－ジメチルホルムアミド（ＤＭＦ）を溶媒とするＧＰＣ装置により行い、ポリスチレン換算値として求められる。具体的な測定条件は、下記のとおりである。
カラム：Ｓｈｏｄｅｘ　ＯＨＰａｋ　ＳＢ－８０６Ｍ　ＨＱ
カラム温度：５０℃
検出器：示差屈折率検出器 ＲＩＤ－２０Ａ（株式会社島津製作所）
流速：０．５ｍｌ／分
　すなわち、本発明において、ポリウレタン樹脂の重量平均分子量は上記測定方法で定義されるものであって、特に、溶媒溶解成分のポリウレタン樹脂の重量平均分子量を意味する。 The weight average molecular weight of the polyurethane resin (X) is determined using a GPC device using N,N-dimethylformamide (DMF) as a solvent, and is determined as a polystyrene equivalent value. The specific measurement conditions are as follows.
Column: Shodex OHPak SB-806M HQ
Column temperature: 50℃
Detector: Differential refractive index detector RID-20A (Shimadzu Corporation)
Flow rate: 0.5 ml/min That is, in the present invention, the weight average molecular weight of the polyurethane resin is defined by the above measurement method, and particularly means the weight average molecular weight of the polyurethane resin as a solvent-soluble component.
　ポリウレタン樹脂（Ｘ）の重量平均分子量は、７０００以上であることが好ましく、８０００以上であることがより好ましく、９０００以上であることがさらに好ましく、１００００以上であることが特に好ましい。また、ポリウレタン樹脂（Ｘ）の重量平均分子量は、４８０００以下であることが好ましく、４５０００以下であることがより好ましく、４３０００以下であることがさらに好ましく、４００００以下であることが特に好ましい。 The weight average molecular weight of the polyurethane resin (X) is preferably 7,000 or more, more preferably 8,000 or more, even more preferably 9,000 or more, and particularly preferably 10,000 or more. Further, the weight average molecular weight of the polyurethane resin (X) is preferably 48,000 or less, more preferably 45,000 or less, even more preferably 43,000 or less, and particularly preferably 40,000 or less.
　本発明において、ポリウレタン樹脂（Ｘ）は、酸価が５～１５ｍｇＫＯＨ／ｇである。この場合、本発明の光学フィルム用接着剤は、高湿熱環境下であっても基材との密着性に特に優れる接着剤となる。酸価が５ｍｇＫＯＨ／ｇ未満になると密着性が低下し、そればかりかポリウレタン樹脂（Ｘ）の製造において乳化分散が難しく、接着剤の形成が困難になる。酸価が１５ｍｇＫＯＨ／ｇを超過すると密着性が大きく低下する。ポリウレタン樹脂（Ｘ）の酸価は７ｍｇＫＯＨ／ｇ以上であることがより好ましく、８ｍｇＫＯＨ／ｇ以上であることがさらに好ましく、９ｍｇＫＯＨ／ｇ以上であることが特に好ましい。ポリウレタン樹脂（Ｘ）の酸価は１４ｍｇＫＯＨ／ｇ以下であることがより好ましく、１３ｍｇＫＯＨ／ｇ以下であることがさらに好ましい。 In the present invention, the polyurethane resin (X) has an acid value of 5 to 15 mgKOH/g. In this case, the adhesive for optical films of the present invention becomes an adhesive that has particularly excellent adhesion to the substrate even under a high humidity and heat environment. If the acid value is less than 5 mgKOH/g, the adhesion will not only deteriorate, but also make emulsification and dispersion difficult in the production of polyurethane resin (X), making it difficult to form an adhesive. If the acid value exceeds 15 mgKOH/g, the adhesion will decrease significantly. The acid value of the polyurethane resin (X) is more preferably 7 mgKOH/g or more, even more preferably 8 mgKOH/g or more, and particularly preferably 9 mgKOH/g or more. The acid value of the polyurethane resin (X) is more preferably 14 mgKOH/g or less, and even more preferably 13 mgKOH/g or less.
　酸価の調整方法は特に限定されず、例えば、公知の方法を広く採用することができる。例えば、ポリオール（Ａ）を構成する成分比を調節することで、ポリウレタン樹脂（Ｘ）の酸価を調節することができる。 The method for adjusting the acid value is not particularly limited, and for example, a wide variety of known methods can be employed. For example, by adjusting the ratio of components constituting the polyol (A), the acid value of the polyurethane resin (X) can be adjusted.
　ポリウレタン樹脂組成物の酸価は、ＪＩＳ　Ｋ００７０－１９９２に準じて測定することができる。 The acid value of the polyurethane resin composition can be measured according to JIS K0070-1992.
　（ポリウレタン樹脂水分散体）
　ポリウレタン樹脂水分散体は、固形分として前記ポリウレタン樹脂（Ｘ）を含み、媒体として水を含む溶媒を含む。溶媒は水のみであってもよいし、水と、炭素数１～３の低級アルコール化合物との混合溶媒であってもよい。 (Polyurethane resin water dispersion)
The aqueous polyurethane resin dispersion contains the polyurethane resin (X) as a solid content and a solvent containing water as a medium. The solvent may be water alone or a mixed solvent of water and a lower alcohol compound having 1 to 3 carbon atoms.
　ポリウレタン樹脂水分散体において、ポリウレタン樹脂の含有割合は特に限定されない。例えば、水系溶媒１００質量部に対し、ポリウレタン樹脂を１０～５０質量部含むことができ、２０～４０質量部含むことが好ましい。 In the polyurethane resin aqueous dispersion, the content ratio of the polyurethane resin is not particularly limited. For example, the polyurethane resin can be contained in 10 to 50 parts by weight, preferably 20 to 40 parts by weight, per 100 parts by weight of the aqueous solvent.
　ポリウレタン樹脂水分散体において、ポリウレタン樹脂（Ｘ）の粒子径は特に限定されず、例えば、公知の接着剤用のポリウレタン樹脂水分散体におけるポリウレタン樹脂の粒子径と同様の範囲とすることができる。例えば、ポリウレタン樹脂（Ｘ）の体積平均粒子径Ｄ５０は１～５００ｎｍ、好ましくは３～３００ｎｍ、より好ましくは５～２５０ｎｍである。 In the aqueous polyurethane resin dispersion, the particle size of the polyurethane resin (X) is not particularly limited, and can be in the same range as the particle size of the polyurethane resin in known aqueous polyurethane resin dispersions for adhesives, for example. For example, the volume average particle diameter D50 of the polyurethane resin (X) is 1 to 500 nm, preferably 3 to 300 nm, more preferably 5 to 250 nm.
　ポリウレタン樹脂水分散体は、ポリウレタン樹脂（Ｘ）及び水以外の成分を含むことができ、例えば、ポリウレタン樹脂水分散体を製造する際に使用する原料が残存していてもよい。斯かる原料は、例えば、界面活性剤、未反応モノマー、未反応鎖伸長剤、副生成物、触媒等である。触媒としては、例えば、金属触媒やアミン系触媒等である。金属触媒としては、例えば、ジブチルチンジラウレート、ジオクチルチンジラウレート、ジブチルチンジオクテート等の錫触媒、オクチル酸鉛、オクテン酸鉛、ナフテン酸鉛等の鉛触媒、オクチル酸ビスマス、ネオデカン酸ビスマスなどのビスマス触媒等が挙げられる。アミン系触媒としては、例えば、トリエチレンジアミン等の３級アミン化合物等が挙げられる。 The aqueous polyurethane resin dispersion may contain components other than the polyurethane resin (X) and water, and for example, raw materials used in producing the aqueous polyurethane resin dispersion may remain. Such raw materials include, for example, surfactants, unreacted monomers, unreacted chain extenders, by-products, catalysts, and the like. Examples of the catalyst include metal catalysts and amine catalysts. Examples of metal catalysts include tin catalysts such as dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dioctate, lead catalysts such as lead octylate, lead octenoate, and lead naphthenate, and bismuth such as bismuth octylate and bismuth neodecanoate. Examples include catalysts. Examples of the amine catalyst include tertiary amine compounds such as triethylene diamine.
　ポリウレタン樹脂の製造方法は特に限定されず、例えば、公知の製造方法を広く採用することができる。特に、後記する乳化分散を利用した製造方法によって、ポリウレタン樹脂を製造することが好ましい。 The method for producing the polyurethane resin is not particularly limited, and for example, a wide variety of known production methods can be employed. In particular, it is preferable to manufacture the polyurethane resin by a manufacturing method using emulsification dispersion, which will be described later.
　ポリウレタン樹脂水分散体の製造方法は特に限定されず、例えば、公知のポリウレタン樹脂水分散体の製造方法を広く採用することができる。特に、乳化分散を利用した製造方法によって、ポリウレタン樹脂水分散体を製造することが好ましい。 The method for producing an aqueous polyurethane resin dispersion is not particularly limited, and for example, a wide variety of known methods for producing an aqueous polyurethane resin dispersion can be employed. In particular, it is preferable to produce the aqueous polyurethane resin dispersion by a production method that utilizes emulsification dispersion.
　乳化分散を利用した製造方法としては、例えば、ポリオール（Ａ）及びポリイソシアネート（Ｂ）を混合処理することでウレタンプレポリマーを調製し、このウレタンプレポリマーを乳化分散することで、ポリウレタン樹脂（Ｘ）が生成し、ポリウレタン樹脂水分散体を得ることができる。 As a manufacturing method using emulsification dispersion, for example, a urethane prepolymer is prepared by mixing polyol (A) and polyisocyanate (B), and by emulsifying and dispersing this urethane prepolymer, polyurethane resin (X ) is produced, and an aqueous polyurethane resin dispersion can be obtained.
　混合処理は溶媒中で行うことができる。斯かる溶媒は、イソシアネート基に対して不活性、かつ、生成するウレタンプレポリマーを溶解し得る性質を有することが好ましい。この観点から、溶媒は、ジオキサン、メチルエチルケトン、ジメチルホルムアミド、テトラヒドロフラン、Ｎ－メチル－２－ピロリドン、アセトン、トルエン、ジオキサン、酢酸エチル、酢酸ブチル、プロピレングリコールモノメチルエーテルアセテート等を挙げることができる。反応で使用した溶媒は最終的に除去することが好ましい。 The mixing process can be performed in a solvent. Such a solvent preferably has properties that are inert to isocyanate groups and capable of dissolving the urethane prepolymer produced. From this point of view, examples of the solvent include dioxane, methyl ethyl ketone, dimethyl formamide, tetrahydrofuran, N-methyl-2-pyrrolidone, acetone, toluene, dioxane, ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, and the like. It is preferable that the solvent used in the reaction is finally removed.
　前記混合処理の温度は特に限定されず、例えば、３０℃～１３０℃とすることができる。混合処理の時間は温度に応じて適宜設定することができ、例えば、０．５時間～１０時間である。混合処理によってポリオール（Ａ）及びポリイソシアネート（Ｂ）の反応が進行し、ウレタンプレポリマーが生成する。溶媒を使用して混合処理をした場合は、ウレタンプレポリマー溶液が得られる。ウレタンプレポリマーが生成した後、乳化分散する前には必要に応じて、中和剤によって中和処理を行うことができる。 The temperature of the mixing treatment is not particularly limited, and can be, for example, 30°C to 130°C. The time for the mixing treatment can be appropriately set depending on the temperature, and is, for example, 0.5 to 10 hours. The reaction between the polyol (A) and the polyisocyanate (B) progresses through the mixing process, and a urethane prepolymer is produced. When a solvent is used for the mixing treatment, a urethane prepolymer solution is obtained. After the urethane prepolymer is produced and before emulsifying and dispersing it, it can be neutralized using a neutralizing agent, if necessary.
　中和剤としては、例えば、水酸化ナトリウム、水酸化カリウム等の不揮発性塩基、トリメチルアミン、トリエチルアミン、ジメチルエタノールアミン、メチルジエタノールアミン、トリエタノールアミン等の三級アミン類、アンモニア等の揮発性塩基等が挙げられる。 Examples of neutralizing agents include nonvolatile bases such as sodium hydroxide and potassium hydroxide, tertiary amines such as trimethylamine, triethylamine, dimethylethanolamine, methyldiethanolamine, and triethanolamine, and volatile bases such as ammonia. Can be mentioned.
　中和処理の前後、好ましくは中和処理と同時にブロック剤をウレタンプレポリマー溶液に添加することもできる。ブロック剤は、残存するＮＣＯ基と反応して、反応を停止させる作用を有する。これにより、ポリウレタン樹脂（Ｘ）の分子量等の調整が容易になる。ブロック剤は、公知のブロック剤を広く使用することができ、例えば、一官能の活性水素基を有する化合物が挙げられ、具体的には、一価のアルコール化合物、一価のアミノ化合物（例えば、ジブチルアミン）が例示される。ブロック剤の使用量は、ポリオール（Ａ）及びポリイソシアネート（Ｂ）の総質量１００質量に対し、５質量部以下とすることができ、好ましくは３質量部以下、より好ましくは１質量部以下、さらに好ましくは０．８質量部以下である。 A blocking agent can also be added to the urethane prepolymer solution before or after the neutralization treatment, preferably at the same time as the neutralization treatment. The blocking agent has the effect of reacting with the remaining NCO groups and stopping the reaction. This facilitates adjustment of the molecular weight, etc. of the polyurethane resin (X). As the blocking agent, a wide variety of known blocking agents can be used. Examples include compounds having a monofunctional active hydrogen group. Specifically, monovalent alcohol compounds, monovalent amino compounds (for example, dibutylamine) is exemplified. The amount of the blocking agent used can be 5 parts by mass or less, preferably 3 parts by mass or less, more preferably 1 part by mass or less, based on 100 parts by mass of the total mass of polyol (A) and polyisocyanate (B). More preferably, it is 0.8 parts by mass or less.
　前記混合処理において、ポリオール（Ａ）及びポリイソシアネート（Ｂ）の使用量は特に限定されず、目的とするポリウレタン樹脂の組成に応じ、適宜使用量を調節することができる。 In the mixing treatment, the amounts of polyol (A) and polyisocyanate (B) used are not particularly limited, and can be adjusted as appropriate depending on the composition of the target polyurethane resin.
　混合処理によって得たウレタンプレポリマーを乳化分散する方法は特に限定されず、公知の方法を広く採用することができる。例えば、ウレタンプレポリマーの溶液と水系溶媒とを混合し、ホモジナイザー等の乳化分散機によってせん断を与えることで、ウレタンプレポリマーを乳化分散することができる。水系溶媒は必要に応じて前記中和剤が含まれていてもよい。 The method for emulsifying and dispersing the urethane prepolymer obtained by the mixing treatment is not particularly limited, and a wide variety of known methods can be employed. For example, the urethane prepolymer can be emulsified and dispersed by mixing a solution of the urethane prepolymer with an aqueous solvent and applying shear using an emulsifying disperser such as a homogenizer. The aqueous solvent may contain the neutralizing agent as required.
　前記乳化分散と同時に、もしくは乳化分散の後、鎖伸長剤を加えて鎖伸張をすることができる。これにより、乳化ミセル中のイソシアシネート基と鎖伸長剤との界面重合反応によりウレア結合が生成するので、乳化ミセル内の架橋密度が向上し、三次元架橋構造が形成される。なお、鎖伸長剤を使用しない場合であっても、ウレタンプレポリマーが水中に乳化分散されることで、系中に存在する水分子が鎖伸長を起こし得る。鎖伸長剤としては、前記ポリアミンを挙げることができる。この場合、最終的に生成するポリウレタン樹脂（Ｘ）は、ポリアミン由来の構造単位を有する。 Simultaneously with the emulsification and dispersion, or after the emulsification and dispersion, a chain extender can be added to extend the chain. As a result, urea bonds are generated by the interfacial polymerization reaction between the isocyanate groups in the emulsified micelles and the chain extender, so that the crosslink density in the emulsified micelles is improved and a three-dimensional crosslinked structure is formed. Note that even when a chain extender is not used, water molecules present in the system can cause chain extension when the urethane prepolymer is emulsified and dispersed in water. Examples of the chain extender include the polyamines mentioned above. In this case, the polyurethane resin (X) finally produced has a structural unit derived from a polyamine.
　ポリアミン（鎖伸長剤）としては、ジアミン化合物やポリアミン化合物が挙げられる。ジアミン化合物としては、エチレンジアミン、トリメチレンジアミン、ピペラジン、イソホロンジアミン、ジエチレントリアミン、ジプロピレントリアミン、アミノ基含有シランカップリング剤などを例示することができ、ポリアミン化合物としては、ジエチレントリアミン、ジプロピレントリアミン、トリエチレンテトラミン等を例示することができる。ポリアミンとしては、その他、ポリカルボジイミド化合物であってもよく、例えば、日清紡ケミカル社のカルボジライト水性樹脂用架橋剤を挙げることができる。 Examples of polyamines (chain extenders) include diamine compounds and polyamine compounds. Examples of diamine compounds include ethylenediamine, trimethylenediamine, piperazine, isophoronediamine, diethylenetriamine, dipropylenetriamine, and amino group-containing silane coupling agents; examples of polyamine compounds include diethylenetriamine, dipropylenetriamine, and triethylene. Examples include tetramine and the like. The polyamine may also be a polycarbodiimide compound, such as a crosslinking agent for carbodilite aqueous resins manufactured by Nisshinbo Chemical Co., Ltd.
　鎖伸長剤（ポリアミン）を使用する場合、その使用量は特に限定されず、例えば、ウレタンプレポリマー中のイソシアネート基と、鎖伸長剤との当量比が１：０．５～１：０．９となるように鎖伸長剤の使用量を調節することができる。 When using a chain extender (polyamine), the amount used is not particularly limited, and for example, the equivalent ratio of the isocyanate group in the urethane prepolymer to the chain extender is 1:0.5 to 1:0.9. The amount of chain extender used can be adjusted so that
　乳化分散にあたり、必要に応じて、各種界面活性剤を使用することができる。界面活性剤としては、例えば、非イオン界面活性剤、アニオン界面活性剤、カチオン界面活性剤等が挙げられる。これらの界面活性剤は、１種を単独で使用しても２種以上を併用してもよい。 In emulsifying and dispersing, various surfactants can be used as necessary. Examples of the surfactant include nonionic surfactants, anionic surfactants, and cationic surfactants. These surfactants may be used alone or in combination of two or more.
　（光学フィルム用接着剤）
　本発明の光学フィルム用接着剤は、ポリウレタン樹脂水分散体（ポリウレタン樹脂（Ｘ）を含む水分散体）を含有する。本発明の光学フィルム用接着剤は、ポリウレタン樹脂水分散体を含む限り、公知の光学フィルム用接着剤と同様の構成とすることができる。光学フィルム用接着剤は、ポリウレタン樹脂水分散体以外に他の添加剤等の成分を含有することもできる。 (Adhesive for optical film)
The adhesive for optical films of the present invention contains a polyurethane resin water dispersion (a water dispersion containing polyurethane resin (X)). The optical film adhesive of the present invention can have the same structure as known optical film adhesives as long as it contains a polyurethane resin aqueous dispersion. The adhesive for optical films can also contain components such as other additives in addition to the polyurethane resin aqueous dispersion.
　本発明の光学フィルム用接着剤を用いて皮膜を形成することができる。本発明の光学フィルム用接着剤を用いて形成される皮膜は、光学フィルム用接着剤の乾燥物（すなわち、ポリウレタン樹脂組成物水分散体の乾燥物）を含む。斯かる皮膜は、例えば、接着機能を発揮することができ、基材との密着性を高めることができ、しかも、高湿熱環境下であっても基材との密着性を高めることができる。特に本発明の光学フィルム用接着剤は、光学フィルム用として好適である。 A film can be formed using the adhesive for optical film of the present invention. The film formed using the adhesive for optical films of the present invention includes a dried product of the adhesive for optical films (that is, a dried product of an aqueous dispersion of a polyurethane resin composition). Such a film can exhibit an adhesive function, for example, and can improve the adhesion to the base material, and can also improve the adhesion to the base material even in a high humidity and heat environment. In particular, the adhesive for optical films of the present invention is suitable for use in optical films.
　皮膜を形成する方法は特に限定されず、例えば、公知の方法で皮膜を形成することができる。例えば、光学フィルム用接着剤を光学フィルム等の基材表面にコーティングし、乾燥等によって水系溶媒を揮発させることで、ポリウレタン樹脂水分散体の乾燥物が形成されるので、この乾燥物を皮膜とすることができる。皮膜の厚みは特に限定されず、用途や目的に応じて適宜の厚みに調節することができる。 The method of forming the film is not particularly limited, and for example, the film can be formed by a known method. For example, by coating the surface of a substrate such as an optical film with an adhesive for optical films and volatilizing the aqueous solvent by drying, etc., a dried polyurethane resin aqueous dispersion is formed. can do. The thickness of the film is not particularly limited, and can be adjusted to an appropriate thickness depending on the use and purpose.
　光学フィルムの種類は特に限定されず、例えば、公知の光学フィルムを広く挙げることができる。光学フィルムとしては、ポリエチレンテレフタレート、ポリエチレンナフタレート、ポリブチレンテレフタレート等の樹脂からなるポリエステル系樹脂；環状ポリオレフィン系樹脂；トリアセチルセルロース、ジアセチルセルロース等の樹脂からなる酢酸セルロース系樹脂；ポリカーボネート系樹脂；アクリル系樹脂；ポリエチレン、ポリプロピレン等のオレフィン樹脂；等のフィルムが例示される。 The type of optical film is not particularly limited, and for example, a wide variety of known optical films can be mentioned. Optical films include polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; cyclic polyolefin resins; cellulose acetate resins such as triacetylcellulose and diacetylcellulose; polycarbonate resins; acrylics. Examples include films of olefin resins such as polyethylene and polypropylene;
　光学フィルムは前記皮膜（本発明の光学フィルム用接着剤から形成される皮膜）を接着層として備えることができる。光学フィルムへの皮膜の形成方法も特に限定されず、例えば、前記光学フィルムに光学フィルム用接着剤をコーティングすることで光学フィルムに皮膜を形成できる。斯かる皮膜（接着層）に他の部材と貼り合わせることで、光学フィルムを備える積層体を得ることができる。他の部材としては、例えば、後記する紫外線硬化樹脂が挙げられる。 The optical film can be provided with the film (film formed from the adhesive for optical films of the present invention) as an adhesive layer. The method for forming a film on an optical film is not particularly limited either, and for example, a film can be formed on an optical film by coating the optical film with an adhesive for optical film. By bonding other members to such a film (adhesive layer), a laminate including an optical film can be obtained. Examples of other members include ultraviolet curing resins described later.
　本発明の光学フィルム用接着剤は、例えば、前記光学フィルムと、紫外線硬化樹脂とを接着させることが好ましい。紫外線硬化型樹脂は特に限定されず、例えば、アクリル系樹脂、シリコーン系樹脂、ポリエステル系樹脂、ウレタン系樹脂、アミド系樹脂、エポキシ系樹脂等が挙げられる。紫外線硬化型樹脂は、例えば、板状、フィルム状等に形成され得る。 The adhesive for optical film of the present invention preferably bonds the optical film and an ultraviolet curing resin, for example. The ultraviolet curable resin is not particularly limited, and examples thereof include acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, and epoxy resins. The ultraviolet curable resin can be formed into, for example, a plate shape, a film shape, or the like.
　本発明の光学フィルム用接着剤を用いて、前記光学フィルムと、前記紫外線硬化樹脂とを接着させる場合、光学フィルムは、ポリエチレンテレフタレートが好ましい。 When the optical film and the ultraviolet curable resin are bonded together using the optical film adhesive of the present invention, the optical film is preferably polyethylene terephthalate.
　前記皮膜を接着層として備える光学フィルムは、たとえ高湿熱環境下であっても基材（光学フィルム）と皮膜との密着性が高いものである。また、斯かる光学フィルムの接着層に他の基材（例えば、ＰＥＴ基材）を接着させた場合であっても、斯かる他の基材をより強固に接着させることができ、高湿熱環境下であっても強固に接着させることができる。 An optical film having the film as an adhesive layer has high adhesion between the base material (optical film) and the film even under a high humidity and heat environment. Furthermore, even if another base material (for example, a PET base material) is bonded to the adhesive layer of such an optical film, the other base material can be bonded more firmly, and it can be used in a high humidity and heat environment. It can be firmly bonded even at the bottom.
　以下、実施例により本発明をより具体的に説明するが、本発明はこれら実施例の態様に限定されるものではない。 Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the embodiments of these Examples.
　（使用原料）
　下記原料から適宜の原料を選択して、ポリウレタン樹脂水分散体を調製した。
　＜ポリオール（Ａ）＞
・ポリエステルポリオール（ａ－１）（数平均分子量２０００、酸価０．５ｍｇＫＯＨ／ｇ）
・ポリエステルポリオール（ａ－２）（数平均分子量１０００、酸価０．５ｍｇＫＯＨ／ｇ）
・ポリエステルポリオール（ａ－３）（数平均分子量２０００、酸価０．５ｍｇＫＯＨ／ｇ）
・ジメチロールプロピオン酸（ｂ）（２，２－ジメチロールプロピオン酸）；（Ｐｅｒｓｔｏｒｐ社製Ｂｉｓ－ＭＰＡ（登録商標））（官能基数２、分子量１３４．１３）
・トリメチロールプロパン
・三洋化成社製「ニューポールＢＰＥ－２０ＮＫ」（登録商標）；その他ポリオール (Raw materials used)
A polyurethane resin aqueous dispersion was prepared by selecting an appropriate raw material from the following raw materials.
<Polyol (A)>
・Polyester polyol (a-1) (number average molecular weight 2000, acid value 0.5mgKOH/g)
・Polyester polyol (a-2) (number average molecular weight 1000, acid value 0.5mgKOH/g)
・Polyester polyol (a-3) (number average molecular weight 2000, acid value 0.5mgKOH/g)
・Dimethylolpropionic acid (b) (2,2-dimethylolpropionic acid); (Bis-MPA (registered trademark) manufactured by Perstorp) (number of functional groups 2, molecular weight 134.13)
・Trimethylolpropane ・“Newpol BPE-20NK” (registered trademark) manufactured by Sanyo Chemical Co., Ltd.; other polyols
　ポリエステルポリオール（ａ－１）、ポリエステルポリオール（ａ－２）及びポリエステルポリオール（ａ－３）は、下記表１に示す配合表に従って製造した。撹拌機、温度計、還流冷却管、滴下槽及び窒素ガス導入管を備えた反応容器に、テレフタル酸、アジピン酸、ネオペンチルグリコール及びエチレングリコールを表１の配合に従って仕込み、窒素気流下で撹拌しながら２５０℃まで昇温した。酸価が５以下になるまで反応を続けた後に、徐々に減圧を行って、１ｍｍＨｇで５時間脱グリコール反応を行い、ポリエステルポリオール（ａ－１）、ポリエステルポリオール（ａ－２）及びポリエステルポリオール（ａ－３）の溶液を得た。 Polyester polyol (a-1), polyester polyol (a-2), and polyester polyol (a-3) were manufactured according to the recipe shown in Table 1 below. Terephthalic acid, adipic acid, neopentyl glycol, and ethylene glycol were placed in a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping tank, and a nitrogen gas introduction tube according to the formulation shown in Table 1, and the mixture was stirred under a nitrogen stream. The temperature was raised to 250°C. After continuing the reaction until the acid value became 5 or less, the pressure was gradually reduced and a deglycol reaction was performed at 1 mmHg for 5 hours to obtain polyester polyol (a-1), polyester polyol (a-2), and polyester polyol ( A solution of a-3) was obtained.
　＜ポリイソシアネート（Ｂ）＞
・４，４’－ジフェニルメタンジイソシアネート（ＭＤＩ）
・トリレンジイソシアネート（ＴＤＩ） <Polyisocyanate (B)>
・4,4'-diphenylmethane diisocyanate (MDI)
・Tolylene diisocyanate (TDI)
　＜ブロック剤及び中和剤＞
・ジブチルアミン（ブロック剤）
・トリエチルアミン（中和剤）
・アンモニア（中和剤） <Blocking agent and neutralizing agent>
・Dibutylamine (blocking agent)
・Triethylamine (neutralizing agent)
・Ammonia (neutralizer)
　表２に示す配合に従い、以下の手順でポリウレタン樹脂水分散体を調製した。なお、表２に掲載の配合条件（使用原料の欄）において、単位は「質量部」であり、また、空欄は、その原料を使用していないこと（すなわち「０」）を意味する。 According to the formulation shown in Table 2, a polyurethane resin aqueous dispersion was prepared according to the following procedure. In addition, in the blending conditions (column of raw materials used) listed in Table 2, the unit is "parts by mass", and a blank column means that the raw material is not used (ie, "0").
　（実施例１）
　ポリエステルポリオール（ａ－１）を８１．４５質量部、及び、ジメチロールプロピオン酸（ｂ）を２．６３質量部からなるポリオール（Ａ）と、ＭＤＩからなるポリイソシアネート（Ｂ）１５．９２質量部と、メチルエチルケトン１００質量部とを混合し、７０～７５℃で１２０分間反応させてウレタンプレポリマー溶液を得た。このウレタンプレポリマー溶液を３５℃まで冷却し、ブロック剤としてジブチルアミンを０．１１質量部及び中和剤としてトリエチルアミン１．８８質量部を添加して中和を行った後、水を徐々に加えながらホモジナイザーを使用して乳化分散させた。この後、メチルエチルケトンを留去し、表２に示すように、重量平均分子量３０８００、酸価が１１であるポリウレタン樹脂を含む水分散体を得た。 (Example 1)
Polyol (A) consisting of 81.45 parts by mass of polyester polyol (a-1) and 2.63 parts by mass of dimethylolpropionic acid (b), and 15.92 parts by mass of polyisocyanate (B) consisting of MDI. and 100 parts by mass of methyl ethyl ketone were mixed and reacted at 70 to 75°C for 120 minutes to obtain a urethane prepolymer solution. This urethane prepolymer solution was cooled to 35°C, neutralized by adding 0.11 parts by mass of dibutylamine as a blocking agent and 1.88 parts by mass of triethylamine as a neutralizing agent, and then water was gradually added. The mixture was emulsified and dispersed using a homogenizer. Thereafter, methyl ethyl ketone was distilled off to obtain an aqueous dispersion containing a polyurethane resin having a weight average molecular weight of 30,800 and an acid value of 11, as shown in Table 2.
　（実施例２～１２）
　使用原料の種類及び配合量を表２のように変更したこと以外は実施例１と同様の方法でポリウレタン樹脂を含む水分散体を得た。 (Examples 2 to 12)
An aqueous dispersion containing a polyurethane resin was obtained in the same manner as in Example 1, except that the types and amounts of raw materials used were changed as shown in Table 2.
　（比較例１～６）
　使用原料の種類及び配合量を表２のように変更したこと以外は実施例１と同様の方法でポリウレタン樹脂を含む水分散体を得た。なお、比較例６では酸価の値が小さすぎるために乳化分散することができず、目的のポリウレタン樹脂を含む水分散体を得ることができなかった。 (Comparative Examples 1 to 6)
An aqueous dispersion containing a polyurethane resin was obtained in the same manner as in Example 1, except that the types and amounts of raw materials used were changed as shown in Table 2. In Comparative Example 6, the acid value was too small to emulsify and disperse, making it impossible to obtain an aqueous dispersion containing the desired polyurethane resin.
　（評価方法）
　各実施例及び比較例で得たポリウレタン樹脂を含む水分散体を用いて、「初期の密着性（ＰＥＴ）」、「高湿熱下での密着性（ＰＥＴ）」、「三層重ねた状態での密着性」、「三層重ねた状態での高湿熱下での密着性」を下記のように評価した。 (Evaluation method)
Using the aqueous dispersion containing the polyurethane resin obtained in each Example and Comparative Example, we evaluated "initial adhesion (PET)", "adhesion under high humidity and heat (PET)", and "three-layered state". The adhesion of the three layers and the adhesion under high humidity and heat in a three-layered state were evaluated as follows.
　＜初期の密着性（ＰＥＴ）＞
　ポリウレタン樹脂接着剤とＰＥＴとの密着性を以下の方法で評価した。基材（ポリエチレンテレフタレート（ＰＥＴ）（「ルミラーＴ－６０」、東レ社製））をイソプロピルアルコールにより脱脂し、次いで、ポリウレタン樹脂を含む水分散体をバーコーターで乾燥膜厚１０μｍになるように塗布し、８０℃で１０分間乾燥し、さらに１２０℃で１０分間乾燥し、ポリウレタン樹脂接着剤（皮膜）がコートされた試験片Ａを得た。この試験片Ａをサンプルとして、２ｍｍ碁盤目試験を実施し、ポリウレタン樹脂接着剤とＰＥＴとの密着性を、下記式
密着性（％）＝１００－（剥がれたマス目の数）
により算出し、密着性が９５％以上である場合を合格とした。 <Initial adhesion (PET)>
The adhesion between the polyurethane resin adhesive and PET was evaluated by the following method. The base material (polyethylene terephthalate (PET) ("Lumirror T-60", manufactured by Toray Industries, Inc.)) was degreased with isopropyl alcohol, and then an aqueous dispersion containing polyurethane resin was applied with a bar coater to a dry film thickness of 10 μm. The sample was dried at 80° C. for 10 minutes and then at 120° C. for 10 minutes to obtain a test piece A coated with a polyurethane resin adhesive (film). Using this test piece A as a sample, a 2 mm grid test was carried out, and the adhesion between the polyurethane resin adhesive and PET was calculated using the following formula: Adhesion (%) = 100 - (number of peeled squares)
The case where the adhesion was 95% or more was determined to be a pass.
　＜三層重ねた状態での密着性＞
　三層重ねた状態でのポリウレタン樹脂接着剤とＰＥＴとの密着性を以下の方法で評価した。前記試験片Ａのポリウレタン樹脂接着剤上に、ＵＶ硬化樹脂処方液をバーコーターで乾燥膜厚７μｍになるように塗布し、８０℃で１分間乾燥し、溶剤を除去し、次いで、ＵＶ硬化樹脂処方液の塗布面に対し、高圧水銀灯を用いて６００ｍＪ／ｃｍ２の紫外線を照射し試験片Ｂを得た。ＵＶ硬化樹脂処方液は、メチルエチルケトン３０質量部、エポキシアクリレート（ＧＸ－８８２１Ｌ－Ｍ９、第一工業製薬製）６８質量部、光重合開始剤（Ｉｒｇａｃｕｒｅ１８４、チバスペシャリティーケミカルズ社製）２質量部を用いて調製した。この試験片Ｂをサンプルとして、２ｍｍ碁盤目試験を実施し、ＵＶ硬化樹脂と、ポリウレタン樹脂接着剤と、ＰＥＴとの密着性を、下記式
密着性（％）＝１００－（剥がれたマス目の数）
により算出し、密着性が７０％以上である場合を合格とした。 <Adhesion with three layers stacked>
The adhesion between the polyurethane resin adhesive and PET in a three-layered state was evaluated by the following method. On the polyurethane resin adhesive of the test piece A, a UV curable resin formulation solution was applied with a bar coater to a dry film thickness of 7 μm, dried at 80° C. for 1 minute, the solvent was removed, and then the UV curable resin was coated with the polyurethane resin adhesive. A test piece B was obtained by irradiating the surface coated with the prescription liquid with ultraviolet rays of 600 mJ/cm 2 using a high-pressure mercury lamp. The UV curing resin formulation liquid used 30 parts by mass of methyl ethyl ketone, 68 parts by mass of epoxy acrylate (GX-8821L-M9, manufactured by Daiichi Kogyo Seiyaku), and 2 parts by mass of a photopolymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals). It was prepared using Using this test piece B as a sample, a 2 mm grid test was carried out, and the adhesion between the UV curing resin, polyurethane resin adhesive, and PET was evaluated using the following formula: Adhesion (%) = 100 - (separated squares) number)
It was calculated by , and the case where the adhesion was 70% or more was considered to be a pass.
　＜高湿熱下での密着性（ＰＥＴ）＞
　前記試験片Ａを温度８５℃、湿度８５％で１６８時間保管後、室温乾燥させてから、２ｍｍ碁盤目試験を実施し、ポリウレタン樹脂接着剤とＰＥＴとの密着性を、下記式
密着性（％）＝１００－（剥がれたマス目の数）
により算出し、密着性が６０％以上である場合を合格とした。 <Adhesion under high humidity and heat (PET)>
After storing the test piece A at a temperature of 85°C and a humidity of 85% for 168 hours, and drying it at room temperature, a 2 mm grid test was conducted, and the adhesion between the polyurethane resin adhesive and PET was determined using the following formula (%). ) = 100 - (number of peeled squares)
It was calculated by , and the case where the adhesion was 60% or more was considered to be a pass.
　＜三層重ねた状態での高湿熱下での密着性＞
　前記試験片Ｂを温度８５℃、湿度８５％で１６８時間保管後、室温乾燥させてから、２ｍｍ碁盤目試験を実施し、ＵＶ硬化樹脂と、ポリウレタン樹脂接着剤と、ＰＥＴとの密着性を、下記式
密着性（％）＝１００－（剥がれたマス目の数）
により算出し、密着性が５０％以上である場合を合格とした。 <Adhesion under high humidity and heat with three layers stacked>
After storing the test piece B at a temperature of 85 ° C. and a humidity of 85% for 168 hours, and drying it at room temperature, a 2 mm grid test was conducted to determine the adhesion between the UV curing resin, polyurethane resin adhesive, and PET. Adhesion (%) = 100 - (number of peeled squares)
It was calculated by , and the case where the adhesion was 50% or more was considered to be a pass.
　＜ヘイズ＞
　得られたポリウレタン樹脂接着剤のヘイズはＪＩＳ　Ｋ　７１３６：２０００に準拠し、濁度計（日本電色製、ＮＤＨ４０００）を用いて測定した。 <Haze>
The haze of the obtained polyurethane resin adhesive was measured using a turbidity meter (manufactured by Nippon Denshoku, NDH4000) in accordance with JIS K 7136:2000.
　表２は、各実施例及び比較例で調製したポリウレタン樹脂水分散体の製造するにあたって採用した配合条件及びそれらのポリウレタン樹脂水分散体から得られた接着剤の評価結果を示している。表２において、ポリウレタン樹脂の酸価の単位は、ｍｇＫＯＨ／ｇである。 Table 2 shows the compounding conditions adopted in producing the polyurethane resin aqueous dispersions prepared in each Example and Comparative Example and the evaluation results of the adhesives obtained from these polyurethane resin aqueous dispersions. In Table 2, the unit of the acid value of the polyurethane resin is mgKOH/g.
　表２の結果から、実施例で得られたポリウレタン樹脂水分散体は、基材（ＰＥＴフィルム）との密着性に優れる接着剤を形成することができ、しかも、たとえ高湿熱環境下であっても基材との密着性に優れる接着剤を形成することができることがわかった。加えて、実施例で得られたポリウレタン樹脂水分散体は、三層重ねた状態での密着性が高湿熱環境下であっても合格レベルであったことから、基材（ＰＥＴフィルム）と紫外線硬化樹脂とを強固に接着できることもわかった。比較例４は、２官能構成成分の総量がポリウレタン樹脂に対して９８質量％を下回るので、高湿熱環境下において基材との密着性が低下するものであった。 From the results in Table 2, the polyurethane resin aqueous dispersion obtained in the example can form an adhesive with excellent adhesion to the base material (PET film), even under a high humidity and heat environment. It was also found that adhesives with excellent adhesion to substrates can be formed. In addition, the polyurethane resin aqueous dispersion obtained in the example had adhesion with the base material (PET film) and ultraviolet rays because the adhesion of the three layers was at an acceptable level even in a high humidity and heat environment. It was also found that it could be strongly bonded to cured resin. In Comparative Example 4, since the total amount of bifunctional components was less than 98% by mass based on the polyurethane resin, the adhesiveness with the base material decreased in a high humidity and heat environment.

Claims (4)

  1. ポリウレタン樹脂（Ｘ）を含む水分散体を含有する光学フィルム用接着剤であって、
    前記ポリウレタン樹脂（Ｘ）は、少なくともポリオール（Ａ）由来の構造単位と、ポリイソシアネート（Ｂ）由来の構造単位とを有し、
    前記ポリオール（Ａ）は、テレフタル酸由来の構造とネオペンチルグリコール由来の構造とを有するポリエステルポリオール（ａ）、及び、ジメチロールプロピオン酸（ｂ）を含み、
    前記ポリオール（Ａ）は、前記ポリエステルポリオール（ａ）を８５質量％以上含み、
    前記ポリウレタン樹脂（Ｘ）の重量平均分子量は５０００～５００００であり、
    前記ポリウレタン樹脂（Ｘ）は、２官能の構成成分を９８質量％以上含有し、
    前記ポリウレタン樹脂（Ｘ）は、酸価が５～１５ｍｇＫＯＨ／ｇである、光学フィルム用接着剤。     An adhesive for optical films containing an aqueous dispersion containing a polyurethane resin (X),
    The polyurethane resin (X) has at least a structural unit derived from the polyol (A) and a structural unit derived from the polyisocyanate (B),
    The polyol (A) includes a polyester polyol (a) having a structure derived from terephthalic acid and a structure derived from neopentyl glycol, and dimethylolpropionic acid (b),
    The polyol (A) contains 85% by mass or more of the polyester polyol (a),
    The weight average molecular weight of the polyurethane resin (X) is 5000 to 50000,
    The polyurethane resin (X) contains 98% by mass or more of a bifunctional component,
    The polyurethane resin (X) is an adhesive for optical films, and has an acid value of 5 to 15 mgKOH/g.
  2. 前記ポリイソシアネート（Ｂ）は、芳香族ポリイソシアネートを含む、請求項１に記載の光学フィルム用接着剤。 The adhesive for optical films according to claim 1, wherein the polyisocyanate (B) includes an aromatic polyisocyanate.
  3. 請求項１又は２に記載の光学フィルム用接着剤の乾燥物を含む、皮膜。 A film comprising a dried product of the optical film adhesive according to claim 1 or 2.
  4. 請求項３に記載の皮膜を接着層として備える、光学フィルム。 An optical film comprising the film according to claim 3 as an adhesive layer.
PCT/JP2023/008694 2022-04-04 2023-03-08 Adhesive for optical film, coating, and optical film WO2023195297A1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016540659A (en) * 2013-09-30 2016-12-28 コーロン インダストリーズ インク Optical film
WO2019004349A1 (en) * 2017-06-29 2019-01-03 Dic株式会社 Urethane resin composition, steel sheet surface treatment agent, and steel sheet having coating film of same

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016540659A (en) * 2013-09-30 2016-12-28 コーロン インダストリーズ インク Optical film
WO2019004349A1 (en) * 2017-06-29 2019-01-03 Dic株式会社 Urethane resin composition, steel sheet surface treatment agent, and steel sheet having coating film of same

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