Active energy ray-curable resin composition, cured product thereof, and protective film

Abstract

Provided are an active energy ray-curable resin composition capable of forming a film having high adhesion to a substrate, excellent weather resistance, and excellent tensile elongation characteristics in a high temperature state, a cured product thereof, and a protective film.　The present invention is an active energy ray-curable resin composition containing a urethane acrylate. The urethane acrylate has a structural unit derived from an alicyclic isocyanate compound, an aromatic polyol compound, a polycarbonate diol, and a (meth)acrylic compound having a hydroxyalkyl group, and the polycarbonate diol has an alicyclic structure or a heterocyclic ring.

Description

Active energy ray curable resin composition, its cured product, and protective film

[0001] This invention relates to an active energy ray-curable resin composition, its cured product, and a protective film.

[0002] Active energy ray curable resin compositions, such as those cured by ultraviolet light, can be used to manufacture protective films for various substrates, for example. Furthermore, active energy ray curable resin compositions are also applied to coatings for various substrates, hard coats, adhesives, and the like.

[0003] Various active energy ray-curable resin compositions have been proposed. For example, Patent Document 1 discloses an active energy ray-curable resin composition mainly composed of a urethane acrylate obtained by reacting a diisocyanate compound, a polycarbonate diol compound, and a hydroxyalkyl (meth)acrylate.

[0004] Japanese Patent Publication No. 2010-037411

[0005] In recent years, active energy ray-curable resin compositions have gained increasing value as protective films for various substrates. Therefore, there is a need for active energy ray-curable resin compositions that can form films with excellent adhesion to various substrates as well as superior weather resistance.

[0006] In addition, since the surface of the substrate to be protected is not flat but may have a curved or curved shape, it is necessary to stretch the film while bonding it to the substrate in order to firmly adhere the protective film to the substrate. For this reason, protective films formed from active energy ray curable resin compositions are also required to have excellent tensile elongation properties, particularly tensile elongation properties at high temperatures.

[0007] From this perspective, there has been a need for an active energy ray curable resin composition that can form a film with high adhesion to the substrate, excellent weather resistance, and excellent tensile elongation characteristics at high temperatures.

[0008] The present invention has been made in view of the above, and aims to provide an active energy ray curable resin composition, its cured product, and a protective film that can form a film with high adhesion to a substrate, excellent weather resistance, and excellent tensile elongation characteristics not only at room temperature but also at high temperatures.

[0009] As a result of diligent research to achieve the above objective, the inventors of this invention discovered that the above objective can be achieved by using urethane acrylate having a specific structural unit as an essential component, and thus completed the present invention.

[0010] In other words, the present invention encompasses, for example, the subject matter described in the following sections: Section 1 An active energy ray curable resin composition containing a urethane acrylate, wherein the urethane acrylate has structural units derived from an alicyclic isocyanate compound, an aromatic polyol compound, a polycarbonate diol, and a (meth)acrylic compound having a hydroxyalkyl group, and the polycarbonate diol has an alicyclic structure or a heterocyclic structure. Section 2 The active energy ray curable resin composition according to Section 1, wherein the polycarbonate diol has an alicyclic structure or a heterocyclic structure in its main chain. Section 3 The active energy ray curable resin composition according to Section 1 or 2, wherein the aromatic polyol compound is a compound having a bisphenol skeleton. Section 4 The active energy ray curable resin composition according to any one of Sections 1 to 3, for use as a protective film. Section 5 A cured product of the active energy ray curable resin composition according to any one of Sections 1 to 4. Section 6 A protective film comprising the cured product according to Section 5.

[0011] The active energy ray curable resin composition of the present invention can form a film that exhibits high adhesion to a substrate, excellent weather resistance, and superior tensile elongation properties not only at room temperature but also at high temperatures.

[0012] Embodiments of the present invention will be described in detail below. In this specification, the expressions "containing" and "including" include the concepts of "containing," "including," "substantially consisting of," and "consisting only of."

[0013] In the numerical ranges described stepwise in this specification, the upper or lower limit of a numerical range in one step can be arbitrarily combined with the upper or lower limit of a numerical range in another step. In the numerical ranges described in this specification, the upper or lower limit of a numerical range may be replaced with values ​​shown in the examples or values ​​that can be uniquely derived from the examples. Furthermore, in this specification, numbers connected by "~" mean a numerical range that includes the numbers before and after "~" as the lower and upper limits.

[0014] The active energy ray curable resin composition of the present invention contains a urethane acrylate. Such a urethane acrylate has structural units derived from alicyclic isocyanate compounds, aromatic polyol compounds, polycarbonate diols, and (meth)acrylic compounds having a hydroxyalkyl group. The polycarbonate diol has an alicyclic structure or a heterocyclic structure.

[0015] In this specification, "(meth)acrylic" means "acrylic" or "methacrylic," "(meth)acrylate" means "acrylate" or "methacrylate," and "(meth)allyl" means "allyl" or "methallyl."

[0016] The active energy ray-curable resin composition of the present invention contains urethane acrylate that includes all of the above structural units, thereby enabling the formation of a film with high adhesion to a substrate, excellent weather resistance, and superior tensile elongation properties not only at room temperature but also at high temperatures. For this reason, the active energy ray-curable resin composition of the present invention can be suitably used as a raw material for forming films.

[0017] The urethane acrylate contained in the active energy ray curable resin composition of the present invention is obtained by reacting an alicyclic isocyanate compound, a polycarbonate diol, an aromatic polyol compound, and a (meth)acrylic compound having a hydroxyalkyl group. Hereinafter, the alicyclic isocyanate compound will be referred to as "(A1) alicyclic isocyanate compound," the polycarbonate diol as "(B1) polycarbonate diol," the aromatic polyol compound as "(B2) aromatic polyol compound," and the (meth)acrylic compound having a hydroxyalkyl group as "(C1) hydroxyalkyl group-containing (meth)acrylic compound." These compounds may also be abbreviated as compound (A1), compound (B1), compound (B2), and compound (C1), respectively.

[0018] (A1) Alicyclic isocyanate compound urethane acrylate contains structural units based on (A1) alicyclic isocyanate compound. (A1) Alicyclic isocyanate compound is an isocyanate compound having an alicyclic structure in its molecule. In particular, (A1) alicyclic isocyanate is a polyisocyanate having at least two isocyanate groups in its molecule.

[0019] The urethane acrylate contains structural units based on (A1) alicyclic isocyanate compounds, which makes it easier for the active energy ray curable resin composition of the present invention to form films that are excellent in both weather resistance and elongation properties at high temperatures.

[0020] An alicyclic structure is one that contains one or more saturated and / or unsaturated carbon ring structures that do not possess aromaticity. There may be two or more such carbon ring structures. The carbon ring structures may have branching aliphatic hydrocarbon structures. The carbon ring structures are bonded to the hydrocarbon chains of the polymer backbone, either directly or via hydrocarbon chains.

[0021] Examples of the aforementioned carbocyclic structures include cycloalkane structures such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cycloundecane, and cyclododecane, as well as cycloalkene structures such as cyclopropene, cyclobutene, cyclopropene, cyclohexene, cycloheptene, and cyclooctene. Examples of bicyclic structures include bicyclic alkane structures such as bicycloundecane, and bicyclic alkene structures such as norbornene and norbornadiene, which can be suitably used. In particular, it is preferable to have a carbocyclic structure with 4 to 8 carbon atoms, more preferably a monocyclic carbocyclic structure with 4 to 8 carbon atoms, even more preferably a monocyclic cycloalkane carbocyclic structure with 4 to 8 carbon atoms, and especially preferable to have a cyclohexane structure.

[0022] Furthermore, the alicyclic structure may also have substituents. As used herein, "substituents" include, for example, C1-C20 alkyl groups, C2-C20 alkenyl groups, C2-C20 alkynyl groups, halogen atoms, carboxyl groups, carbonyl groups, sulfonyl groups, sulfone groups, cyano groups, and the like.

[0023] (A1) The alicyclic isocyanate compound may have one or more alicyclic structures in its molecule, preferably two or more, and more preferably two. Furthermore, (A1) the alicyclic isocyanate compound may have two or more isocyanate groups in its molecule, and more preferably two.

[0024] (A1) Specific examples of alicyclic isocyanate compounds include, for example, isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate (also known as 4,4'-methylenebis(cyclohexyl isocyanate)), 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis(isocyanate methyl)cyclohexane, etc.

[0025] (B1) Polycarbonate diol urethane acrylate contains structural units based on (B1) polycarbonate diol. (B1) Polycarbonate diol is a diol compound having an alicyclic or heterocyclic structure within its molecule.

[0026] Because urethane acrylate contains structural units based on (B1) polycarbonate diol, the active energy ray curable resin composition of the present invention facilitates the formation of films that exhibit both excellent adhesion to the substrate and excellent elongation properties at high temperatures.

[0027] In (B1) polycarbonate diol, the alicyclic structure is synonymous with the alicyclic structure in the (A1) alicyclic isocyanate compound. The alicyclic structure of (B1) polycarbonate diol preferably has a carbon-4 to carbon-8 carbon-16 structure, more preferably a monocyclic carbon-4 to carbon-8 carbon-16 structure, even more preferably a monocyclic cycloalkane carbon-16 structure, and particularly preferably a cyclohexane structure.

[0028] (B1) In polycarbonate diols, a heterocyclic ring means, for example, a ring structure in which at least one (preferably one) of the carbon atoms forming the alicyclic structure is replaced by a heteroatom. Examples of heteroatoms include nitrogen, oxygen, sulfur, and phosphorus atoms.

[0029] (B1) The polycarbonate diol preferably has an alicyclic or heterocyclic structure in its main chain. In this case, the active energy ray curable resin composition of the present invention readily forms a film with high adhesion to the substrate and excellent elongation properties at high temperatures.

[0030] (B1) The polycarbonate diol is more preferably having an alicyclic structure in its main chain, even more preferably having a carbon-cyclic structure of a monocyclic cycloalkane with 4 to 8 carbon atoms in its main chain, and particularly preferably having a cyclohexane structure in its main chain.

[0031] (B1) Examples of polycarbonate diols include diol compounds having a structural unit represented by the following formula (1).

[0032]

[0033] In formula (1), R represents a divalent group based on the aforementioned alicyclic structure or heterocyclic ring. Therefore, examples of R include divalent groups based on a carbon ring structure of a monocyclic cycloalkane structure having 4 to 8 carbon atoms. Specific examples include divalent groups based on a cyclohexane structure, that is, a cyclohexylene group (-C ６ H １０ ). It is particularly preferred to have

[0034] When the polycarbonate diol (B1) is a diol compound having a structural unit represented by the above formula (1), both ends are, for example, R-OH.

[0035] When the polycarbonate diol (B1) is a diol compound having a structural unit represented by the above formula (1), it can have other structural units in addition to the said structural unit. For example, the polycarbonate diol (B1) may include a diol compound having a structural unit represented by the following formula (2) in addition to the structural unit represented by the above formula (1).

[0036]

[0037] In formula (2), R １ represents a chain-like alkylene group. The chain-like alkylene group is, for example, an alkylene group having 20 or fewer carbon atoms, preferably 16 or fewer, more preferably 12 or fewer, still more preferably 10 or fewer, and particularly preferably 8 or fewer. Also, the number of carbon atoms of the chain-like alkylene group is preferably 1 or more, more preferably 2 or more, and still more preferably 3 or more. The chain-like alkylene group as R １ may be linear or may have a branched chain. Specific examples of R １ include -CH ２ -, -C ２ H4-, -C ３ H ６ -, -C ４ H ８ -, -C ６ H １２ -.

[0038] (B1) When the polycarbonate diol contains a diol compound having a structural unit represented by the formula (2) and such a structural unit is arranged at the terminal, the terminal of the structural unit represented by the formula (2) is, for example, R １ -OH.

[0039] (B1) The polycarbonate diol may be a diol compound composed only of the structural unit represented by the formula (1), or may be a diol compound having both the structural unit represented by the formula (1) and the structural unit represented by the formula (2).

[0040] (B1) When the polycarbonate diol is a diol compound having both the structural unit represented by the formula (1) and the structural unit represented by the formula (2), the content ratio of the structural unit represented by the formula (1) is preferably 10 mol% or more, more preferably 20 mol% or more, further preferably 25 mol% or more, still further preferably 40 mol% or more, and particularly preferably 50 mol% or more with respect to the total amount of the structural unit represented by the formula (1) and the structural unit represented by the formula (2). The content ratio of the structural unit represented by the formula (1) may be 70 mol% or more with respect to the total amount of the structural unit represented by the formula (1) and the structural unit represented by the formula (2).

[0041] (B1) When the polycarbonate diol is a diol compound having both the structural unit represented by the formula (1) and the structural unit represented by the formula (2), (B1) the polycarbonate diol may further contain other structural units, or may be a diol compound composed only of the structural unit represented by the formula (1) and the structural unit represented by the formula (2).

[0042] (B1) When the polycarbonate diol is a diol compound having both the structural unit represented by the formula (1) and the structural unit represented by the formula (2), (B1) the polycarbonate diol may be a random polymer in which these structural units are randomly arranged, or may be a block polymer or an alternating polymer.

[0043] Furthermore, if (B1) polycarbonate diol is a diol compound consisting only of the structural unit represented by formula (1), it may also contain a diol compound having the structural unit represented by formula (2). In other words, (B1) polycarbonate diol may be a mixture.

[0044] (B1) The number average molecular weight of the polycarbonate diol is not particularly limited, but is preferably 400 or more, more preferably 600 or more, even more preferably 800 or more, and also preferably 100,000 or less, more preferably 10,000 or less, even more preferably 5,000 or less, and particularly preferably 2,000 or less.

[0045] In this invention, the number-average molecular weight can refer to the value obtained by GPC measurement. Specifically, this is performed using a GPC apparatus with tetrahydrofuran (THF) as the solvent, and the value is determined as a polystyrene equivalent. The specific measurement conditions are as follows: Column: Polystyrene gel column manufactured by Tosoh Corporation (TSKgel G4000HXL + TSKgel G3000HXL + TSKgel G2000HXL + two TSKgel G1000HXL columns connected in series in this order) Column temperature: 40°C Detector: Differential refractive index detector (RID-6A manufactured by Shimadzu Corporation) Flow rate: 1 ml / min

[0046] Furthermore, if (B1) polycarbonate diol is a commercially available product and its number-average molecular weight is known from the manufacturer's guaranteed value, etc., that value can be used as the number-average molecular weight of (B1) polycarbonate diol.

[0047] (B1) Polycarbonate diol is not particularly limited in its manufacturing method, and for example, (B1) polycarbonate diol can be manufactured by known methods for manufacturing carbonate diol. In addition, (B1) polycarbonate diol can be obtained from commercially available products. Examples of commercially available (B1) polycarbonate diol include UBE's "ETERNACOLL®" series, specifically "ETERNACOLL® UC-100", "ETERNACOLL® UM-90 (3 / 1)", "ETERNACOLL® UM-90 (1 / 1)", and "ETERNACOLL® UM-90 (1 / 3)".

[0048] (B2) Aromatic polyol compound urethane acrylate contains structural units based on (B2) aromatic polyol compounds. (B2) Aromatic polyol compounds are polyol compounds having an aromatic ring structure within the molecule. In particular, (B2) aromatic polyol compounds are polyols having at least two hydroxyl groups within the molecule. Note that (B2) aromatic polyol compounds do not have a carbonate structure within the molecule.

[0049] Because the urethane acrylate contains structural units based on (B2) aromatic polyol compounds, the active energy ray curable resin composition of the present invention facilitates the formation of films that exhibit excellent adhesion to the substrate and elongation properties at high temperatures.

[0050] Aromatic ring structures can include monocyclic, dicyclic, tricyclic, or tetracyclic aryl groups, which may have, for example, 6 to 18 carbon atoms. Examples of aryl groups include phenyl, 1-naphthyl, 2-naphthyl, 2-biphenyl, 3-biphenyl, 4-biphenyl, and 2-anthuryl.

[0051] (B2) The aromatic polyol compound preferably has one or more of the aromatic ring structures within the molecule, more preferably one or two, and even more preferably two. (B2) The aromatic polyol compound preferably has a benzene ring structure.

[0052] Furthermore, the (B2) aromatic polyol compound preferably has two or more hydroxyl groups in its molecule, and more preferably has two.

[0053] (B2) The aromatic polyol compound is preferably a compound having a bisphenol skeleton, and more preferably a compound having a bisphenol A skeleton.

[0054] Furthermore, the (B2) aromatic polyol compound may be an alkylene oxide adduct. Specifically, the (B2) aromatic polyol compound may be a compound obtained by adding an alkylene oxide to a diol compound having an aromatic ring, that is, it may be an aromatic polyether polyol. Among these, the (B2) aromatic polyol compound is preferably an alkylene oxide adduct of bisphenol, and more preferably an alkylene oxide adduct of bisphenol A. The alkylene oxide adduct has a degree of polymerization of about 1 to 100, preferably 50 or less, more preferably 10 or less, even more preferably 8 or less, and particularly preferably 5 or less.

[0055] Examples of alkylene oxides include ethylene oxide and propylene oxide.

[0056] (B2) Examples of aromatic polyol compounds include ethylene oxide adducts of bisphenol A and propylene oxide adducts of bisphenol A.

[0057] (B2) Aromatic polyol compounds can be manufactured by known methods or obtained from commercially available products. Examples of commercially available aromatic polyol compounds include ADEKA's "BPX series" of polyether polyols and Sanyo Chemical Industries' Newpol® BP series.

[0058] (C1) Hydroxyalkyl group-containing (meth)acrylic compound urethane acrylate contains structural units based on the (C1) hydroxyalkyl group-containing (meth)acrylic compound. By containing structural units based on the (C1) hydroxyalkyl group-containing (meth)acrylic compound, the urethane acrylate can be cured by introducing acrylic moieties into it.

[0059] Examples of hydroxyalkyl groups include alkyl groups having 1 to 20 carbon atoms and having at least one hydroxyl group, preferably having 2 to 10 carbon atoms.

[0060] Examples of (C1) hydroxyalkyl group-containing (meth)acrylic compounds include (meth)acrylic esters having a hydroxyalkyl group. Examples of (C1) hydroxyalkyl group-containing (meth)acrylic compounds include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. The (C1) hydroxyalkyl group-containing (meth)acrylic compound is preferably a methacrylic compound, and among these, hydroxyethyl methacrylate and hydroxypropyl methacrylate are particularly preferred, as they offer improved adhesion to polyethylene terephthalate substrates and tend to have excellent elongation properties at high temperatures.

[0061] The urethane acrylate contained in the active energy ray curable resin composition of the present invention can be obtained by reacting an alicyclic isocyanate compound, an aromatic polyol compound, a polycarbonate diol, and a (meth)acrylic compound having a hydroxyalkyl group. As a result, the urethane acrylate can have structural units derived from an alicyclic isocyanate compound, an aromatic polyol compound, a polycarbonate diol, and a (meth)acrylic compound having a hydroxyalkyl group.

[0062] It should be noted, for the sake of clarity, that if urethane acrylate contains structural units derived from methacrylic compounds having a hydroxyalkyl group, then strictly speaking, urethane acrylate is urethane methacrylate. Therefore, in this invention, urethane acrylate also includes urethane methacrylate.

[0063] The urethane acrylate preferably contains 30% by mass or more of structural units based on (B1) polycarbonate diol. This makes it easier to form a film in which the active energy ray curable resin composition of the present invention has high adhesion to the substrate and excellent elongation properties at high temperatures.

[0064] The urethane acrylate more preferably contains 40% by mass or more of structural units based on (B1) polycarbonate diol, even more preferably 45% by mass or more, particularly preferably 50% by mass or more, and also preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, even more preferably 80% by mass or less, and particularly preferably 75% by mass or less.

[0065] The urethane acrylate preferably contains 5 parts by mass or more of structural units based on (B2) aromatic polyol compounds, more preferably 8 parts by mass or more, even more preferably 9 parts by mass or more, particularly preferably 10 parts by mass or more, and also preferably 40 parts by mass or less, more preferably 35 parts by mass or less, even more preferably 30 parts by mass or less, and particularly preferably 25 parts by mass or less.

[0066] The urethane acrylate preferably contains 5 to 40% by mass of structural units based on (A1) alicyclic isocyanate compounds. This makes it easier for the active energy ray curable resin composition of the present invention to form films with excellent weather resistance and high-temperature elongation properties.

[0067] The urethane acrylate more preferably contains 8% by mass or more of structural units based on (A1) alicyclic isocyanate compounds, even more preferably 10% by mass or more, even more preferably 15% by mass or more, particularly preferably 17% by mass or more, and more preferably 38% by mass or less, even more preferably 35% by mass or less, and particularly preferably 30% by mass or less.

[0068] From another perspective, it is preferable that the urethane acrylate contains 15 to 80 parts by mass of structural units based on (A1) an alicyclic isocyanate compound with respect to 100 parts by mass of structural units based on (B1) a polycarbonate diol. This makes it easier for the active energy ray curable resin composition of the present invention to form a film with excellent weather resistance and high-temperature elongation properties.

[0069] The urethane acrylate more preferably contains 18 parts by mass or more of structural units based on (A1) an alicyclic isocyanate compound, more preferably 20 parts by mass or more, particularly preferably 25 parts by mass or more, more preferably 75 parts by mass or less, more preferably 70 parts by mass or less, and particularly preferably 60 parts by mass or less, per 100 parts by mass of structural units based on (B1) a polycarbonate diol.

[0070] The urethane acrylate preferably contains 1 to 10% by mass of structural units based on a (C1) hydroxyalkyl group-containing (meth)acrylic compound. More preferably, the urethane acrylate contains 1.5% by mass or more of structural units based on a (C1) hydroxyalkyl group-containing (meth)acrylic compound, even more preferably 2% by mass or more, particularly preferably 2.5% by mass or more, more preferably 8% by mass or less, even more preferably 7% by mass or less, and particularly preferably 6% by mass or less.

[0071] The urethane acrylate contained in the active energy ray-curable resin composition of the present invention may contain structural units other than those based on (A1) alicyclic isocyanate compounds, (B1) polycarbonate diols, (B2) aromatic polyol compounds, and (C1) hydroxyalkyl group-containing (meth)acrylic compounds, as long as the effects of the present invention are not inhibited. Alternatively, the urethane acrylate contained in the active energy ray-curable resin composition of the present invention may consist only of structural units based on (A1) alicyclic isocyanate compounds, (B1) polycarbonate diols, (B2) aromatic polyol compounds, and (C1) hydroxyalkyl group-containing (meth)acrylic compounds. The urethane acrylate contained in the active energy ray curable resin composition of the present invention preferably has a total amount of 50% by mass or more of structural units based on (A1) an alicyclic isocyanate compound, (B1) a polycarbonate diol, (B2) an aromatic polyol compound, and (C1) a hydroxyalkyl group-containing (meth)acrylic compound, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0072] As described above, urethane acrylate has polymerizable sites (acrylic sites) within its molecule, such as an acrylic ester site. At least one polymerizable site is present in the urethane acrylate molecule, preferably two or more. This allows the urethane acrylate to have the property of curing upon irradiation with active energy rays.

[0073] The urethane acrylate may be a random polymer, a block polymer, or an alternating polymer.

[0074] The number-average molecular weight of the urethane acrylate is preferably 800 or more, more preferably 2000 or more, even more preferably 5000 or more, even more preferably 7000 or more, and also preferably 1,000,000 or less, more preferably 100,000 or less, even more preferably 50,000 or less, and particularly preferably 20,000 or less.

[0075] The method for producing urethane acrylate is not particularly limited, and known methods for producing urethane acrylate can be widely employed. For example, urethane acrylate can be produced by an addition reaction (polyaddition) using raw materials containing (A1) an alicyclic isocyanate compound, (B1) a polycarbonate diol, (B2) an aromatic polyol compound, and (C1) a hydroxyalkyl group-containing (meth)acrylic compound.

[0076] In this case, an addition reaction (polyaddition) can be performed first using a compound other than the (C1) hydroxyalkyl group-containing (meth)acrylic compound. Once the isocyanate content in the reaction system reaches a predetermined numerical range, the (C1) hydroxyalkyl group-containing (meth)acrylic compound can be added to the reaction system.

[0077] In the above addition reaction, a catalyst may be used as needed. Examples of catalysts include organotin compounds, specifically tin octoate, dibutyltin dilaurate, dioctyltin dineodecanoate, dioctyltin dilaurate, manganese, cobalt, lead, bismuth stanate, lead stanate, zirconium octoate, zinc octoate, dibutyltin-bis-o-phenylphenylene, dibutyltin-S,S-dibutyldithiocarbonate, triphenylantimony dichloride, dibutyltin maleate, dibutyltin diacetate, dibutyltin dilaurate mercaptide, triethylenediamine, bismuth stearate, lead stearate, and dimethyltin dichloride. The amount of catalyst used can be adjusted in the range of 0.001 to 5 parts by mass per 100 parts by mass of the total amount of compound (A1), compound (B1), compound (B2), and compound (C1).

[0078] The above addition reaction can also be carried out using other solvents as needed, and can be performed in the presence of polymerization inhibitors such as hydroquinone monomethyl ether.

[0079] The temperature of the above addition reaction is not particularly limited and can be, for example, around 30 to 100°C, preferably 50 to 80°C. The reaction time is also not particularly limited and can be set within an appropriate range depending on the reaction temperature. For example, the reaction can be carried out until the amount of free isocyanate is 10% by mass or less, preferably 5% by mass or less, and more preferably 0.1% by mass or less, relative to the isocyanate compound used.

[0080] Active Energy Ray Curable Resin Composition The active energy ray curable resin composition of the present invention may contain other components as long as it contains the urethane acrylate as an essential component. Examples of other components include polymerizable compounds such as vinyl monomers, polymerization initiators, and solvents.

[0081] For example, any known polymerization initiator can be widely used. Preferably, the polymerization initiator is one that initiates the polymerization reaction by irradiation with active energy rays; a photopolymerization initiator is an example of such an initiator.

[0082] Examples of photopolymerization initiators include aromatic ketones such as benzophenone, aromatic compounds such as anthracene and α-chloromethylnaphthalene, and sulfur compounds such as diphenyl sulfide and thiocarbamate. Examples of polymerization initiators using active energy rays other than visible light, such as ultraviolet light, include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, xanthones, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone, benzoin propyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, 2-hydroxy-2-methyl-1- Examples include phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone).

[0083] The amount of polymerization initiator contained in the active energy ray curable resin composition is not particularly limited and can be 0.01 to 10 parts by mass per 100 parts by mass of the urethane acrylate, preferably 0.03 to 5 parts by mass.

[0084] The aforementioned solvent may be added, for example, to improve the coating properties of the active energy ray curable resin composition of the present invention. Examples of solvents include chlorinated hydrocarbons such as chloroform and 1,2-dichloroethane; ether compounds such as diethyl ether and tetrahydrofuran; aliphatic hydrocarbons such as hexane and heptane; alicyclic hydrocarbons such as cyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene; ketone compounds such as acetone and methyl ethyl ketone; ester compounds such as vinyl acetate; alcohols such as methanol, ethanol, isopropyl alcohol, and t-butanol; formamides such as N,N-dimethylformamide and N,N-dimethylacetamide; pyrrolidones such as 2-pyrrolidone and N-methylpyrrolidone; and dimethyl sulfoxides.

[0085] The amount of solvent contained in the active energy ray curable resin composition of the present invention is not particularly limited. For example, the amount of solvent can be adjusted so that the concentration of the urethane acrylate is 1 to 100% by mass, and considering the coating properties, it is preferably about 5 to 50% by mass.

[0086] The active energy ray curable resin composition of the present invention may optionally contain polymerization inhibitors, photosensitizers, photostabilizers, silane coupling agents, ultraviolet absorbers, catalysts, leveling agents, defoamers, polymerization accelerators, antioxidants, flame retardants, infrared absorbers, antistatic agents, slip agents, plasticizers, dispersants, and the like.

[0087] The active energy ray curable resin composition of the present invention preferably contains 50% by mass or more of the urethane acrylate, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, based on the total mass excluding the solvent.

[0088] The method for preparing the active energy ray-curable resin composition of the present invention is not particularly limited, and can be prepared, for example, by mixing urethane acrylate with components to be added as needed.

[0089] The active energy ray curable resin composition of the present invention contains the urethane acrylate and has the property of curing when exposed to active energy rays, thereby forming a cured product. The active energy ray is preferably ultraviolet light, but other examples include electron beams, gamma rays, carbon arc lamps, xenon lamps, and metal halide lamps.

[0090] The method for curing the active energy ray-curable resin composition of the present invention is not particularly limited, and for example, known methods can be widely employed in the present invention. For example, a coating film of the active energy ray-curable resin composition of the present invention can be formed on a substrate, and a cured product of the active energy ray-curable resin composition can be formed by irradiating the coating film with active energy rays.

[0091] A film can be formed using the active energy ray-curable resin composition of the present invention. Since such a film contains the cured product of the active energy ray-curable resin composition of the present invention, it exhibits high adhesion to the substrate, excellent weather resistance, and superior tensile elongation properties at high temperatures. Of course, the film formed using the active energy ray-curable resin composition of the present invention also exhibits superior tensile elongation properties at low temperatures (for example, room temperature).

[0092] Conventional protective films obtained from active energy ray-curable resin compositions did not exhibit good tensile elongation properties at high temperatures. Therefore, when attempting to bond them to curved or curved substrates while heating, the films did not stretch well, making bonding difficult. In contrast, the films obtained from the active energy ray-curable resin composition of the present invention exhibit excellent tensile elongation properties at high temperatures and excellent adhesion to substrates, thus providing excellent adhesion even to curved or curved substrates.

[0093] Since the active energy ray-curable resin composition of the present invention possesses the above-mentioned properties, it can be applied to various types of films, and is particularly suitable for use in protective films.

[0094] The type of substrate to which the protective film is laminated is not particularly limited, and various resin substrates can be cited as examples. In terms of particularly excellent adhesion, acrylic substrates, polyethylene terephthalate substrates, etc., are preferred as substrates.

[0095] The thickness of the film formed from the active energy ray curable resin composition of the present invention is not particularly limited. It can be set to an appropriate range depending on the intended application, and for example, it can be the same as that of a conventional protective film.

[0096] In specifying the inventions contained herein, the components (properties, structures, functions, etc.) described in each embodiment of this disclosure may be combined in any way. That is, this disclosure encompasses all subject matter consisting of any combination of the combinatable components described herein.

[0097] The present invention will be described more specifically below with reference to examples, but the present invention is not limited to the embodiments of these examples.

[0098] (Raw Materials) Urethane acrylate was prepared by selecting appropriate raw materials from those listed below, and an active energy ray curable resin composition containing the urethane acrylate was prepared.

[0099] (A1) Alicyclic isocyanate compounds: Hydrogenated MDI: 4,4'-dicyclohexylmethane diisocyanate (Evonik "VESTANAT H12MDI") IPDI: Isophorone diisocyanate (Evonik "VESTANAT IPDI")

[0100] Other aliphatic isocyanate compounds / HMDI: Hexamethylene diisocyanate

[0101] (B1) Polycarbonate diol UM-90 (3 / 1): UBE Corporation's "ETERNACOLL (registered trademark) UM-90 (3 / 1)" UC-100: UBE Corporation's "ETERNACOLL (registered trademark) UC-100" UM-90 (1 / 3): UBE Corporation's "ETERNACOLL (registered trademark) UM-90 (1 / 3)"

[0102] Other polycarbonate diols - UH-100: UBE Corporation's "ETERNACOLL (registered trademark) UH-100"

[0103] (B2) Aromatic polyol compounds: BPX-11: Polyether polyol "BPX-11" manufactured by ADEKA Corporation (propylene oxide adduct of bisphenol A) BPX-55: Polyether polyol "BPX-55" manufactured by ADEKA Corporation (propylene oxide adduct of bisphenol A) BPE-40: Newpol "BPE" manufactured by Sanyo Chemical Industries, Ltd. (ethylene oxide adduct of bisphenol A)

[0104] Aliphatic polyol compound EXCENOL 420: AGC Inc. "EXCENOL 420" (aliphatic polyol) (polycarbonate diol without alicyclic or heterocyclic structures)

[0105] (C1) Hydroxyalkyl group-containing (meth)acrylic compounds: HEMA: Hydroxyethyl methacrylate, HPMA: Hydroxypropyl methacrylate, HEA: Hydroxyethyl acrylate

[0106] (Example 1) An active energy ray curable resin composition containing urethane acrylate was prepared by selecting the raw materials shown in Example 1 of the formulation table in Table 1. Specifically, 50 parts by mass of methyl ethyl ketone was mixed with 58.00 parts by mass of (B1) polycarbonate diol (UM-90 (3 / 1)), 10.24 parts by mass of (B2) aromatic polyol compound (BPX-11), 27.90 parts by mass of (A1) alicyclic isocyanate compound (hydrogenated MDI), and 0.01 parts by mass of dioctyl tin dilaurate as a catalyst, and the mixture was reacted at 70-75°C for 120 minutes. This reaction yielded a urethane prepolymer solution with a free isocyanate group content (on a solids basis) of 1.50% by mass. To the obtained urethane prepolymer solution, 3.86 parts by mass of a (C1) hydroxyalkyl group-containing (meth)acrylic compound (HEMA) was added, and the reaction was carried out at 70-75°C until the free isocyanate group content (on a solids basis) was less than 0.1% by mass, to obtain a urethane acrylate solution with a number average molecular weight (Mn) of 10,000. The obtained urethane acrylate solution was mixed with 3 parts by mass of "Omnirad 184" manufactured by IGM Resins B.V. as a photopolymerization initiator to obtain an active energy ray curable resin composition.

[0107] (Examples 2-6) Active energy ray curable resin compositions were obtained in the same manner as in Example 1, except that the raw materials and their proportions were selected as shown in the formulation table in Table 1.

[0108] (Examples 7-12) Active energy ray curable resin compositions were obtained in the same manner as in Example 1, except that the raw materials and their proportions were selected as shown in the formulation table in Table 2.

[0109] (Examples 13-18) Active energy ray curable resin compositions were obtained in the same manner as in Example 1, except that the raw materials and their proportions were selected as shown in the formulation table in Table 3.

[0110] (Comparative Examples 1-3) Active energy ray curable resin compositions were obtained in the same manner as in Example 1, except that the raw materials and their proportions were selected as shown in the formulation table in Table 4.

[0111] (Evaluation Method) The physical properties (adhesion to the substrate, weather resistance, and tensile elongation characteristics) of the films formed using the active energy ray curable resin compositions obtained in each example and comparative example were evaluated according to the following procedure.

[0112] [Film Preparation 1] The active energy ray-curable resin compositions obtained in each example and comparative example were applied to a 100 μm thick PET (polyethylene terephthalate) substrate (Toyobo Co., Ltd.'s "Cosmoshine A4360") to a dry film thickness of approximately 10 μm, and then dried in an 80°C oven for 1 minute to form a film on the PET film. Subsequently, under a nitrogen atmosphere, a high-pressure mercury lamp (80 W / cm x 1 lamp) was used to an integrated illuminance of 600 mJ / cm². ２ The coating was cured by irradiating it with a laser to form a film. This resulted in a laminate consisting of a film formed on a PET substrate.

[0113] [Film Preparation 2] A laminate was obtained by forming a film on an acrylic substrate using the same procedure as in Film Preparation 1, except that a 2 mm thick acrylic substrate ("Acrylic Test Piece" manufactured by Nippon Test Panel Co., Ltd.) was used instead of a PET substrate.

[0114] [Adhesion to PET Substrate] On the film surface formed on the laminate surface obtained in Film Preparation 1, cuts were made with a cutter knife on the cured coating surface to create 100 grids of 2 mm x 2 mm. Cellophane adhesive tape was then applied over these grids and rapidly peeled off three times. The number of grids that remained without peeling was counted, and the adhesion to the substrate (PET film) was evaluated according to the following criteria. <<Evaluation Criteria>> A: 100 grids remained, indicating excellent adhesion to the substrate. B: 80 or more but less than 100 grids remained, indicating good adhesion to the substrate. C: 60 or more but less than 80 grids remained, indicating good adhesion to the substrate. D: Less than 60 grids remained, indicating poor adhesion to the substrate.

[0115] [Adhesion to Acrylic Substrate] On the film surface formed on the laminate surface obtained in Film Preparation 2, cuts were made with a cutter knife on the cured coating surface to create 100 grids of 2 mm x 2 mm. Cellophane adhesive tape was then applied over these grids and rapidly peeled off three times. The number of grids that remained without peeling was counted, and the adhesion to the substrate (acrylic film) was evaluated according to the following criteria. <Evaluation Criteria> A: 100 grids remained, indicating excellent adhesion to the substrate. B: 80 or more but less than 100 grids remained, indicating good adhesion to the substrate. C: 60 or more but less than 80 grids remained, indicating good adhesion to the substrate. D: Less than 60 grids remained, indicating poor adhesion to the substrate.

[0116] [Weather Resistance] The weather resistance of the film obtained in Film Preparation 1 was evaluated using a Sunshine Weather Meter S80 manufactured by Suga Test Instruments Co., Ltd. The test conditions were: light source: carbon arc lamp, irradiation time: 100 hours. The color difference ΔE*ab of the film was measured before and after the test using a color difference meter (SD6000 manufactured by Nippon Denshoku Industries, Ltd.) and evaluated based on the following criteria. The smaller the difference in color before and after the test, the higher the weather resistance of the film. <<Criteria>> A: ΔE*ab value less than 0.10 B: ΔE*ab value 0.10 or more, less than 0.30 C: ΔE*ab value 0.30 or more, less than 0.50 D: ΔE*ab value 0.50 or more

[0117] [Tensile Elongation (130°C)] The tensile elongation (%) at 130°C of the films obtained from the active energy ray curable resin compositions of each example and comparative example was evaluated by tensile testing using a universal testing machine. Specifically, the active energy ray curable resin composition was applied to release paper to a cured thickness of 100 μm, and cured in a UV irradiation machine to form a film. The obtained film was punched out with a dumbbell to create test pieces for tensile testing. A tensile test (tensile speed: 50 mm / min) was performed in a 130°C atmosphere using an Autograph (precision universal testing machine) from Shimadzu Corporation, and the elongation at which the test piece broke (tensile elongation) was measured and evaluated based on the following criteria. <<Criteria>> A: Tensile elongation of 120% or more, indicating extremely excellent tensile elongation characteristics. B: Tensile elongation of 100% or more and less than 120%, indicating excellent tensile elongation characteristics. C: Tensile elongation of 80% or more and less than 100%, indicating good tensile elongation characteristics. D: It was less than 80%, indicating poor tensile elongation properties.

[0118] [Tensile Elongation (20°C)] The tensile elongation was measured using the same procedure as for [Tensile Elongation (130°C)], except that the tensile test was performed in a 25°C atmosphere, and was evaluated based on the following criteria. <<Criteria>> A: Tensile elongation of 120% or more, indicating excellent tensile elongation characteristics. B: Tensile elongation of 100% or more but less than 120%, indicating excellent tensile elongation characteristics. C: Tensile elongation of 80% or more but less than 100%, indicating good tensile elongation characteristics. D: Less than 80%, indicating poor tensile elongation characteristics.

[0119] Tables 1-4 show the formulation conditions and evaluation results for the active energy ray-curable resin compositions prepared in each example and comparative example. In Tables 1-4, blank spaces indicate that the raw material was not used.

[0120] The results in Tables 1-4 show that urethane acrylate containing all the specified structural units can form a film with high adhesion to the substrate, excellent weather resistance, and superior tensile elongation characteristics at high temperatures.

[0121]

[0122]

[0123]

[0124]

Claims

1. An active energy ray curable resin composition containing urethane acrylate, wherein the urethane acrylate has structural units derived from an alicyclic isocyanate compound, an aromatic polyol compound, a polycarbonate diol, and a (meth)acrylic compound having a hydroxyalkyl group, and the polycarbonate diol has an alicyclic structure or a heterocyclic structure.

2. The active energy ray curable resin composition according to claim 1, wherein the polycarbonate diol has an alicyclic structure or a heterocyclic structure in its main chain.

3. The active energy ray curable resin composition according to claim 1, wherein the aromatic polyol compound is a compound having a bisphenol skeleton.

4. An active energy ray curable resin composition according to any one of claims 1 to 3, for use in protective films.

5. A cured product of the active energy ray curable resin composition according to any one of claims 1 to 3.

6. A protective film comprising the cured product described in claim 5.

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