Optical film and its applications

Abstract

To provide an optical film which can achieve both bending resistance and surface hardness.SOLUTION: There is formed an optical film having an average thickness of 20 to 300 μm by a cured product of a curable composition comprising an epoxy(meth)acrylate represented by the following formula (1). [wherein, X represents a specific linking group, ring Z1a and ring Z1b are identical to or different from each other and represent an arene ring, R1a and R1b are identical to or different from each other and represent a substituent, m1 and m2 are identical to or different from each other and represent an integer of 0 or more, A1a and A1b are identical to or different from each other and represent a linear or branched chain alkylene group, n1 and n2 are identical to or different from each other and represent an integer of 1 or more, R2a and R2b are identical to or different from each other and represent a hydrogen atom or a methyl group.] The optical film is incorporated into a display part of an image display device which is used by repeated bending and causes no crease or rupture even after repeated bending 100000 times using a bending tester.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention provides a display cover sheet that has excellent bending resistance and surface hardness. The present invention relates to an optical film that can be used for various purposes and its uses. [Background technology]

[0002] In recent years, smartphones have become significantly more sophisticated, and foldable smartphones is one of the proposals. Foldable smartphones are smartphones that fold a single screen. It can be folded and unfolded, and can be used as both a smartphone and a tablet. It has the advantage of combining the portability of a smartphone with the large screen of a tablet. However, there are many technical challenges to overcome before it can be put into practical use.

[0003] The display of a foldable smartphone is made of glass to enable folding. Instead of liquid crystal displays (LCDs) that use a plate, organic E displays can be made entirely of plastic. The transparent electrode of the OLED is made of a flexible material. Instead of indium tin oxide (ITO), which is weak and prone to breakage, it uses metal such as copper mesh. Furthermore, low-temperature polysilicon TFT (Thin Film TFT) A polyimide substrate is used instead of a glass substrate for forming a transistor. For OLED encapsulation, a thin film encapsulation layer and a barrier film are used in combination instead of glass encapsulation. It has been done.

[0004] Above the OLED are a touch sensor, a circular polarizer, and a λ / 4 retarder for sunglasses readables. Film materials such as a cover sheet are laminated, and OCA (Optic al Clear Adhesive) and PSA (Pressure Sensitiv) The cover sheet is covered with an adhesive layer such as a hard adhesive. The touch sensor is an out-cell type with a surface treatment layer such as a polyester coating. A metal mesh electrode is formed on a polyethylene terephthalate (PET) film. In the OLED panel type, a metal mesh electrode is formed on the thin film sealing layer of the OLED. For a mobile smartphone to be practical, all of these films and thin layers must be In addition to fulfilling each of these functions, it also boasts unprecedented bending resistance (it can be bent repeatedly without breaking). It has bending durability that prevents damage and creases, and it does not have a tendency to crease even if it is left bent for a long time. It must also have bending stability (which suppresses deformation).

[0005] In particular, the cover sheet is used on the outermost surface, so it must meet strict requirements for surface hardness and abrasion resistance. However, there is a trade-off between surface hardness and bending resistance, so both properties must be considered. It is not easy to achieve both of these. The bending resistance is related to the elastic modulus and thickness of the film. The lower the modulus of elasticity, the higher the bending resistance (there is no breakage or deformation due to bending). The thinner the film, the higher the bending resistance becomes, but on the other hand, the lower the elastic modulus becomes. The thinner the film thickness, the lower the surface hardness tends to be. As the material for the casing, various transparent polyimides with excellent bending resistance have been proposed (Patent Document References 1-4).

[0006] On the other hand, 9,9-bis(aryl)fulvapor is a material that can achieve both high hardness and flexibility. A cured epoxy acrylate having an olefin structure and an oxyalkylene chain has been proposed. (Patent Document 5). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2018-28073 [Patent Document 2] Japanese Patent Application Publication No. 2019-052287 [Patent Document 3] WO2017 / 191830 issue [Patent Document 4] Japanese Patent Application Publication No. 2019-051718 [Patent Document 5] Japanese Patent Application Publication No. 2017-186513 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the transparent polyimides of Patent Documents 1 to 4 all have insufficient surface hardness, To use it as a bar sheet, hard coating is required. Therefore, the thickness of the hard coat layer becomes thicker, which causes the problem of increased curl due to curing shrinkage. In addition, bending resistance is not just about durability against repeated bending. It is also required that the film does not crease when kept in a folded state for a long time. Mido has high durability against repeated bending, but it is a transparent polyimide with a hard coat layer. The mid section shows signs of bending and needs to be improved.

[0009] On the other hand, in Patent Document 5, the use of the cured product described therein is a cover for a foldable terminal. - Sheets are not envisioned at all, and the physical properties required for such uses are not No suggestion has been made.

[0010] Therefore, an object of the present invention is to provide an optical film and a method for manufacturing the same that can achieve both bending resistance and surface hardness. The purpose is to provide its uses. [Means for solving the problem]

[0011] As a result of extensive research to achieve the above object, the present inventors have discovered that a specific aromatic hydrocarbon skeleton A film formed from a cured product of an epoxy acrylate having the above formula has excellent bending resistance, Furthermore, the present inventors have found that the aromatic hydrocarbons have excellent surface hardness and have completed the present invention. The hydrocarbon skeleton consists of a rigid 9,9-bis(aryl)fluorene skeleton and a flexible 9,9-bis(aryl)fluorene skeleton of appropriate length. By selecting a structure having a soft oxyethylene chain, it is possible to achieve both high flexibility and surface hardness. Furthermore, the film formed from this cured product has high transparency and small retardation, When used as a sheet, there is no rainbow or light leakage, and it also provides excellent visibility through polarized sunglasses. I also found that.

[0012] One preferred embodiment of the present invention is a display unit for an image display device that is repeatedly folded and used. The optical film to be incorporated is an epoxy (meth)acrylate represented by the following formula (1): The curable composition is formed from a cured product containing cellulose acetate.

[0013] [ka]

[0014] [In the formula, X represents a linking group selected from the group represented by the following formula (2):

[0015] [ka]

[0016] (In the formula, R 3a and R 3b are the same or different and represent a hydrogen atom, a fluorine atom, a chlorine atom, atom, bromine atom, iodine atom, C 1-9 Alkyl group, C 1-5 Alkoxy group, C 4-12 Cycloalkyl groups, C 6-12 Aryl group, C 2-5 Alkenyl group or C 7-17 Ara R represents an alkyl group. 3a and R 3b may be bonded to form a carbocyclic or heterocyclic ring; (s indicates an integer of 1 or greater) Ring Z 1a and ring Z 1b are the same or different and represent an arene ring, R 1a and R 1b are the same or different and represent a substituent, m1 and m2 are the same or different and represent integers of 0 or more, A 1a and A 1b may be the same or different and may be a straight-chain or branched-chain alkylene n1 and n2 are the same or different and represent an integer of 1 or more; R 2a and R 2b are the same or different and represent a hydrogen atom or a methyl group. ]

[0017] Furthermore, in one preferred embodiment of the present invention, the epoxy (meth)acrylate is represented by the following formula: 1a) is an epoxy (meth)acrylate.

[0018] [ka]

[0019] (In the formula, R 4 represents a substituent, k represents an integer of 0 to 8, Ring Z 1a and ring Z 1b , A 1a and A 1b , n1 and n2, R 1a and R 1b , m1 and m2, R 2a and R 2b (same as above)

[0020] Furthermore, one preferred embodiment of the present invention is a compound in which, in the formula (1), ring Z 1a and ring Z 1b are the same or different and represent a benzene ring or a naphthalene ring, R 1a and R 1b are identical or different, C 1-4 Alkyl group or C 6-10 Aryl group, and n1+n2 represents an integer of 2 to 30.

[0021] Furthermore, in one preferred embodiment of the present invention, the epoxy (meth)acrylate is represented by the following formula: 1b) is an epoxy (meth)acrylate.

[0022] [ka]

[0023] (wherein n1+n2 represents an integer of 3 to 20)

[0024] Furthermore, one preferred embodiment of the present invention is an epoxy (meth)acrylate represented by the formula (1a). The proportion of the acrylate in the epoxy (meth)acrylate represented by the formula (1) is 70 to 10 0 mol%.

[0025] In a further preferred embodiment of the present invention, the curable composition further contains an ultraviolet absorber.

[0026] In a further preferred embodiment of the present invention, the cured product is a photocured product.

[0027] Furthermore, in one preferred embodiment of the present invention, the in-plane retardation Ro(550) of the optical film is The thickness direction retardation Rth(589) is 100 nm or less.

[0028] Furthermore, in one preferred embodiment of the present invention, the total light transmittance of the optical film is 85% or more. and the spectral transmittance at 380 nm is 8% or less.

[0029] Furthermore, in one preferred embodiment of the present invention, the optical film is a cover sheet for a display. is.

[0030] In a further preferred embodiment of the present invention, the optical film is a polarizing plate protective film.

[0031] Furthermore, in one preferred embodiment of the present invention, the average thickness of the optical film is 20 to 200 μm. is.

[0032] Furthermore, one preferred embodiment of the present invention is a method for manufacturing a polarizer comprising the optical film and a polyvinyl alcohol polarizer. The polarizing plate is made by bonding the above with an adhesive.

[0033] Furthermore, in one preferred embodiment of the present invention, the optical film contains an ultraviolet absorber, and The adhesive does not contain an ultraviolet absorber.

[0034] Furthermore, one preferred embodiment of the present invention is an image display device comprising the optical film.

[0035] Furthermore, in one preferred embodiment of the present invention, the image display device includes an organic EL display. .

[0036] Furthermore, in one preferred embodiment of the present invention, the image display device is a foldable mobile information terminal. be.

[0037] Furthermore, one of the preferred embodiments of the present invention is a display device for use by repeatedly folding the display device. The optical film is placed on the surface of the display unit, and the optical film is used as a cover sheet. This is how to do it.

[0038] In this specification and claims, the number of carbon atoms in a substituent is represented by C1, C6, C 10 For example, "C1 alkyl group" refers to an alkyl group with one carbon atom. means "C 6-10 The term "aryl group" refers to an aryl group having 6 to 10 carbon atoms. [Effects of the Invention]

[0039] In the present invention, the optical film is made of an epoxy acrylate having a specific aromatic hydrocarbon skeleton. Since it is made of a cured product, it has excellent bending resistance and surface hardness. The aromatic hydrocarbon skeleton is a rigid 9,9-bis(aryl)fluorene skeleton. By selecting a structure having a flexible oxyalkylene chain of an appropriate length, high flexibility can be obtained. It has both excellent transparency and surface hardness, and has a small phase difference, making it suitable for use as a cover sheet. There is no rainbow or light leakage even when using polarized sunglasses, and the visibility is excellent. When the film contains an ultraviolet absorber, it is effective as a protective film for polarizing plates, and is thin and Even if the thickness is too small, bleeding out of the UV absorber can be suppressed, and both thinning and UV absorption ability can be achieved. Adhesion to photons can also be improved. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 1 is a schematic diagram showing a manufacturing process for an optical film according to a preferred embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram illustrating a method for bending an optical film in a bending stability test. DETAILED DESCRIPTION OF THE INVENTION

[0041] Preferred embodiments of the present invention will be described below, but the present invention does not include these embodiments. Not limited.

[0042] [Epoxy (meth)acrylate] In one preferred embodiment of the present invention, the curable composition comprises an epoxy compound represented by the formula (1) Contains meth)acrylates.

[0043] In the formula (1), the linking group of X is -(CH2) s -s in this case must be an integer greater than or equal to 1. However, it is preferably 1 to 10, more preferably 1 to 6, and even more preferably 2 to 4. .

[0044] Among the linking groups X, R 3a and R 3b is an aliphatic ring such as a cyclohexane ring or a cyclodecane ring A linking group forming a carbon ring such as an aromatic hydrocarbon ring or an aromatic hydrocarbon ring is preferred, and From point R 3a and R 3b More preferably, R 3a and R 3b A linking group forming a fluorene ring is most preferred.

[0045] In the formula (1), ring Z1a and ring Z 1b Aromatic hydrocarbon rings (or As for the arene ring, a monocyclic aromatic hydrocarbon ring such as a benzene ring (monocyclic arene ring) Polycyclic aromatic hydrocarbon rings are broadly classified into polycyclic aromatic hydrocarbon rings (polycyclic arene rings). Examples include condensed polycyclic aromatic hydrocarbon rings (condensed polycyclic arene rings), ring-assembled aromatic hydrocarbons, Examples include elementary rings (ring assembly arene rings).

[0046] The fused polycyclic arene rings include fused bicyclic arene rings and fused tricyclic arene rings. Examples of the fused bicyclic arene ring include naphthyl arene rings, fused bicyclic arene rings, fused tetracyclic arene rings, and the like. Fused bicyclic C rings such as talen ring 10-16 arene rings. Examples of the anthracene ring include an anthracene ring and a phenanthrene ring.

[0047] As a ring-assembled arene ring, biC 6-12 Arene rings and other biarene rings, terephthalic acid rings 6- 12 Examples include terarene rings such as arene rings. 6-12 As an arene ring is a biphenyl ring; a binaphthyl ring; a 1-phenylnaphthalene ring, a 2-phenylnaphthalene ring Examples include phenylnaphthalene rings such as phenyl rings. 6-12 As the arene ring, terphenylene ring and the like.

[0048] Among these aromatic hydrocarbon rings, C rings such as benzene ring, naphthalene ring, and biphenyl ring 6-12 An arene ring is preferred, and C is preferred because it can achieve both bending resistance and surface hardness. 6- 10 An arene ring is more preferred, and a benzene ring is most preferred.1a and Ring Z 1b What is Although they may be different rings, they are usually the same ring.

[0049] In the formula (1), R 1a and R 1b The substituents represented by the formula (I) are those represented by the formula (I) on the epoxy group. There is no particular limitation as long as the substituent is non-reactive to the hydroxy group, but halogen atoms, hydrocarbon groups, alkoxy groups, hydroxy ... koxy group, cycloalkyloxy group, aryloxy group, aralkyloxy group, alkyl Thio group, cycloalkylthio group, arylthio group, aralkylthio group, acyl group, nitro group, a cyano group, and the like.

[0050] The halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. Examples of the hydride group include an alkyl group, a cycloalkyl group, an aryl group, and an aralkyl group. Examples of alkyl groups include methyl, ethyl, n-propyl, and isopropyl groups. , n-butyl group, s-butyl group, isobutyl group, t-butyl group, etc. Condition C 1-10 Alkyl groups, preferably linear or branched C 1-6 alkyl groups, and Preferably linear or branched C 1-4 Examples include alkyl groups. The group includes C groups such as cyclopentyl and cyclohexyl groups. 5-10 Cycloalkyl groups Examples of the aryl group include a phenyl group, an alkylphenyl group, and a biphenylyl group. C groups such as naphthyl groups 6-12 Examples of the alkylphenyl group include aryl groups. Examples of the phenyl group include methylphenyl group (tolyl group) and dimethylphenyl group (xylyl group). Aralkyl groups include C groups such as benzyl and phenethyl.6-10 Aryl-C 1-4 Examples include alkyl groups.

[0051] The alkoxy group includes a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, an isopropyl group, an ethyl ... Linear or branched C such as isobutoxy group, t-butoxy group 1-10 Alkoxy groups, etc. Examples of the cycloalkyloxy group include C 5- 10 Examples of the aryloxy group include phenoxy and cycloalkyloxy groups. C groups, etc. 6-10 Examples of the aralkyloxy group include: C such as benzyloxy group 6-10 Aryl-C 1-4 Alkyloxy groups are examples. The alkylthio group includes a methylthio group, an ethylthio group, a propylthio group, an n-butylthio group, and C such as butylthio group and t-butylthio group 1-10 alkylthio groups. The alkylthio group is a C cyclohexylthio group. 5-10 cycloalkylthio group The arylthio group includes C groups such as thiophenoxy groups. 6-10 Ally Examples of aralkylthio groups include C arylthio groups such as benzylthio groups. 6-1 0Aryl-C 1-4 Examples of the acyl group include an acetyl group. C etc. 1-6 Examples include an acyl group.

[0052] Representative examples of these substituents include halogen atoms, alkyl groups, cycloalkyl groups, Aralkyl groups and other hydrocarbon groups; alkoxy groups; acyl groups; nitro groups; cyano groups; substituted aryl groups Preferred R 1a and R 1b Examples of the alkyl group include alkyl groups, cycloaliphatic groups, and cycloaliphatic groups. Examples of the alkyl group include a methyl group. Any linear or branched C 1-6 Examples of the cycloalkyl group include alkyl groups. is a C such as cyclohexyl group. 5-8 cycloalkyl groups, and aryl groups. For example, C 6-14 Examples of the alkoxy group include: Linear or branched C such as methoxy group 1-4 Alkoxy groups are particularly preferred. As alkyl groups, linear or branched C groups such as methyl groups 1-4 Examples of alkyl groups include Substituent R 1a and substituent R 1b may be different substituents, but usually they are the same substituent. It is a conversion base.

[0053] R 1a and R 1b The numbers of substitutions m1 and m2 may be integers of 0 or more, and the ring Z 1a and ring Z 1b can be selected appropriately depending on the type of Preferably, the numbers of substitutions m1 and m2 are, in the following order, integers of 0 to 4, integers of 0 to 3, It is an integer of 0 to 2, 0 or 1, and 0 is most preferable. The substitution numbers m1 and m2 are different substitutions. The number of substitutions m1 and m2 may be two or more, but usually they are the same. If above, R is 2 or more 1a or R 1b The types may be the same or different. In particular, when m1 and m2 are 1, the ring Z 1a and ring Z1b is a benzene ring, and naphthalene a phenyl ring or biphenyl ring, R 1a and R 1b is preferably a methyl group. 1a and R 1b The substitution position of ring Z is not particularly limited. 1a and ring Z 1b And, Ether Bond It is sufficient that the substituent is at a position other than the bond (—O—) and the bonding position to the linking group X.

[0054] In the formula (1), the alkylene group A 1a and A 1b Examples include ethylene groups, protons, and Pyrene group (1,2-propanediyl group), trimethylene group, 1,2-butanediyl group, tetramethyl group Straight or branched chain C such as tramethylene group 2-6 alkylene groups. Among these, linear or branched C 2-4 Alkylene groups are preferred, and may be linear or branched. Chain C 2-3 Alkylene groups are more preferred, and ethylene groups are most preferred.

[0055] Oxyalkylene group (OA 1a ) and oxyalkylene groups (OA 1b ) repetition count (Number of moles added) n1 and n2 may each be an integer of 1 or more, for example, 1 to 20 The preferred repeat numbers n1 and n2 are 1 to 15, 1 to 15, and It is preferably an integer of 10, 2 to 9, 2 to 8, or 2 to 7, and most preferably an integer of 3 to 6. , n1 and n2 may be the same or different. When the number is 2 or more, two or more oxyalkylene groups (OA 1a ) or an oxyalkylene group ( Office Automation 1b) may be the same or different. A 1a ) and oxyalkylene group (OA 1b ) may be the same as each other or different. It's fine.

[0056] In the present specification and claims, the "number of repeats (number of moles added)" is the average It may be an average value (arithmetic mean value, additive mean value) or an average number of moles added. , as well as the range of preferred integers.

[0057] Ring Z 1a and ring Z 1b is a monocyclic aromatic hydrocarbon ring such as a benzene ring or a biphenyl In the case of an aromatic hydrocarbon ring having an assembled ring such as a ring, n1+n2 is, for example, an integer of about 2 to 30. The number can be selected from the following ranges, with the preferred ranges being 3 to 25, 4 to 20, and 5 is an integer of 10 to 18, 6 to 16, 7 to 15, 8 to 14, or 9 to 13, and most preferably 10 to 18. 12. These n1 + n2 ranges are 1a and ring Z 1b is a benzene ring It may be a range of cases.

[0058] On the other hand, ring Z 1a and ring Z 1b is a condensed polycyclic aromatic hydrocarbon ring such as a naphthalene ring In this case, n1+n2 should be 3 or more, since the cured product tends to become rigid and its flexibility tends to decrease. It may be an integer of 4 or more, preferably an integer of 4 or more, more preferably an integer of 5 or more, and most preferably Preferably, it is an integer of 6 or more. 1a and ring Z 1b Condensed polycyclic rings such as naphthalene rings In the case of an aromatic hydrocarbon ring of the formula, n1+n2 can be selected from the range of integers of about 3 to 30. The preferred ranges are as follows: 4 to 25, 5 to 20, 6 to 18, 7 to 15, 8 It may be an integer of 1 to 13, and is most preferably an integer of 10 to 15.

[0059] As mentioned above, n1+n2 may be an integer, but in the compound represented by the formula (1), It may be the average value (or the average number of moles added) of the molecular aggregate. n1+n2 is, for example, 2 You can select from a range of about 30, and 1a and ring Z 1b Regardless of the type, 2.5 to 2 The range can be selected from about 5, and the preferred ranges are as follows: 3 to 20, 5 to 18 , 6~17, 7~16, 7.5~15, 8~14, 9~13, 9.5~12.5, 10~ 12, and most preferably 10.5 to 11.5.

[0060] If the value of n1+n2 is too small, the crosslink density of the cured product tends to be high, and further, It is difficult to achieve flexibility due to the alkylene group, so it is necessary to strike a good balance between surface hardness and bending resistance. Conversely, if the value of n1 + n2 is too large, the crosslink density of the cured product will be significantly low. The surface hardness and bending resistance are not well balanced, and the unit amount (unit Ring Z per mass 1a and ring Z 1b The content of the skeleton (the arene ring via the linking group X) Since the number of moles of the skeleton to which the bond is attached is also reduced, the low birefringence and high heat resistance derived from the skeleton are obtained. There is a risk that excellent properties such as the above may be deteriorated.

[0061] In particular, as will be described later, the skeleton is preferably a 9,9- In the case of a bis(aryl)fluorene structure, it has extremely low birefringence and heat resistance. Even if the value of n1+n2 is relatively large, it is possible to achieve a balance between high hardness and flexibility (bending resistance). The skeleton is a 9,9-bis(aryl)fluorene skeleton. n1+n2 of the epoxy (meth)acrylate can be selected from integers of about 3 to 20. The preferred ranges are as follows: 4 to 18, 4 to 17, 5 to 16, 7 to 15, 8 The range is preferably an integer of 1 to 14, 9 to 13, and most preferably an integer of 10 to 12. If the side chain is relatively long, the side chain is preferably an integer of 4, more preferably an integer of 9 to 13, and even more preferably an integer of 10 to 12. Despite this, it exhibits high hardness.

[0062] The substitution position of the oxyalkylene group-containing group is not particularly limited, and the ring Z 1a and ring Z 1b Suitable for For example, ring Z 1a and ring Z 1b is a benzene ring, The position may be any of the 2nd to 6th positions, including the 2nd, 3rd, and 4th positions, and is preferably is at the 3-position or 4-position, most preferably at the 4-position. 1a and ring Z 1b Naphthalene In the case of a ring, the substitution position is often the 5th to 8th positions of the naphthyl group. For example, The 1st or 2nd position of the naphthalene ring is substituted with the group X (1-naphthyl or 2-naphthyl) The substitution positions are preferably 1,5-position, 1,6-position, or 2,6-position. The most preferred relationship is the 2- and 6-positions. 1a and ring Z 1b is a biphenyl ring When the arene ring bonded to the linking group X or the arene ring adjacent to this arene ring is For example, the 3- or 4-position of the biphenyl ring may be bonded to the linking group X. When the 3-position of the biphenyl ring is bonded to the linking group X, the oxyalkylene group-containing The substitution position of the group may be any of the 2-position, 4- to 6-position, and 2'- to 6'-position. Positions 4, 5, 6, 3', and 4', with positions 4, 6, and 4' being preferred, and position 6 being the most preferred. preferable.

[0063] base R 2a and R 2b may be either a hydrogen atom or a methyl group, but From the viewpoint of the above, a hydrogen atom is preferred. 2a and group R 2b may be different from each other, , are usually identical.

[0064] The epoxy (meth)acrylate represented by the formula (1) has surface hardness and bending resistance. and the above formula (1a ) is preferably an epoxy (meth)acrylate represented by the formula (1b), Epoxy (meth)acrylate is most preferred.

[0065] In the formula (1a), ring Z 1a and ring Z 1b , A 1a and A 1b , n1 and n2, R 1a and R 1b , m1 and m2, R 2a and R 2b Regarding, preferred The form is the same as that of the formula (1).

[0066] In addition, the ring Z bonded to the 9th position of fluorene 1a and ring Z 1b The substitution position of is as described above. However, for example, ring Z 1a and ring Z 1bWhen the ring is a benzene ring, any one of the 2- to 6-positions The 2-, 3-, and 4-positions may be mentioned, preferably the 3- and 4-positions, and most preferably the The position is usually 4 as in the formula (1b).

[0067] In the formula (1a), R 4 The substituents represented by the formula (I) are non-reactive with epoxy groups. There is no particular limitation as long as the substituent is a carboxylic acid group, but examples thereof include hydrocarbon groups such as alkyl groups and aryl groups, and silyl groups. Examples of the alkyl group include methyl, ethyl, n, and n-alkyl groups. -linear or branched chain, such as propyl, isopropyl, n-butyl, or t-butyl groups Condition C 1-6 Examples of aryl groups include C alkyl groups such as phenyl groups. 6- 10 Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and the like. These substituents may be used alone or in combination of two or more. do.

[0068] Among these substituents, alkyl groups, cyano groups and halogen atoms are preferred. is branched chain C 1-4 Alkyl groups are particularly preferred. Furthermore, linear or branched C 1-4 Among alkyl groups, linear or branched C 1-3 Alkyl groups are preferred, such as methyl groups. Which C 1-2 Alkyl groups are particularly preferred.

[0069] R 4 The number of substitutions k is an integer of 0 to 8, and the preferred range is 0 to 8 in the following stepwise manner: It is an integer of 6, an integer of 0 to 4, or an integer of 0 to 2, and 0 is the most preferable. In this case, each R 5The types of may be the same or different. When the above formula is used, two or more R substituted on the same or different benzene rings 4 The types of They may be the same or different. 4 The substitution position of is not particularly limited, and for example, It may be at any of the 2- to 7-positions of the orene ring, and is usually at any of the 2-, 3-, and 7-positions. It is Reka.

[0070] Among the epoxy (meth)acrylates represented by the formula (1a), representative compounds are For example, in the formula (1a), the ring Z 1a and ring Z 1b is a benzene ring, n1= Compounds where n2=1, i.e., 9,9-bis[(3-(meth)acryloyloxy- 2-hydroxypropoxy)alkoxyphenyl]fluorenes; And, Ring Z 1a and ring Z 1b is a benzene ring or a naphthalene ring, and n1 and n2 are 2 to 1 0, i.e., 9,9-bis[(3-(meth)acryloyloxy-2-hydroxybenzoyl] 9,9-bis[(3-(hydroxypropoxy)polyalkoxyphenyl]fluorenes; Meth)acryloyloxy-2-hydroxypropoxy)polyalkoxynaphthyl]fur Examples include olefins.

[0071] 9,9-bis[(3-(meth)acryloyloxy-2-hydroxypropoxy)al As the [koxyphenyl]fluorenes, there are mentioned those in which the ring Z in the formula (1a) 1a and ring Z 1b is a substituted or unsubstituted benzene ring, k=0, A 1a and A 1b C 2-4 Alkire Compounds in which n1=n2=1, such as (1a-1) 9,9-bis[4-(2-( 3-(meth)acryloyloxy-2-hydroxypropoxy)ethoxy)phenyl] Fluorene, 9,9-bis[4-(2-(3-(meth)acryloyloxy-2-hydroxybenzoyl) 9,9-bis[(3-(meth)phenyl)propoxy]phenyl]fluorene, etc. Acryloyloxy-2-hydroxypropoxy)C 2-4 Alkoxyphenyl]fluoro (1a-2) 9,9-bis[4-(2-(3-(meth)acryloyloxy-2- Hydroxypropoxy)ethoxy)-3-methylphenyl]fluorene, 9,9-bis[ 4-(2-(3-(meth)acryloyloxy-2-hydroxypropoxy)propoxy )-3-methylphenyl]fluorene, 9,9-bis[4-(2-(3-(meth)acrylamide (2-hydroxypropoxy)ethoxy)-3-isopropylphenyl] Fluorene, 9,9-bis[4-(2-(3-(meth)acryloyloxy-2-hydroxybenzoyl) 9,9-bis[4-( ...(4-((4-((4-((4-((4-(((4-(((4-(((4-((((4-(((((((((((((((((((( (2-(3-(meth)acryloyloxy-2-hydroxypropoxy)ethoxy)-3 -t-butylphenyl]fluorene, 9,9-bis[4-(2-(3-(meth)acryloyl (2-hydroxypropoxy)ethoxy)-3,5-dimethylphenyl]fur Olenolic acid, 9,9-bis[4-(2-(3-(meth)acryloyloxy-2-hydroxy (propoxy)ethoxy)-3-t-butyl-6-methylphenyl]fluorene, 9,9- Bis[4-(2-(3-(meth)acryloyloxy-2-hydroxypropoxy)ethoxy]ethoxy] 9,9-bis[(3-(meth)amino]-2,5-dimethylphenyl]fluorene, acryloyloxy-2-hydroxypropoxy)C 2-4 Alkoxy-mono or di C1 -4 (1a-3) 9,9-bis[4-(2-(3-(methylphenyl)fluorene]; Acryloyloxy-2-hydroxypropoxy)ethoxy)-3-cyclohexyl phenyl]fluorene, 9,9-bis[4-(2-(3-(meth)acryloyloxy- 2-hydroxypropoxy)propoxy)-3-cyclohexylphenyl]fluorene Which 9,9-bis[(3-(meth)acryloyloxy-2-hydroxypropoxy)C 2-4 Alkoxy-C 5-10 Cycloalkylphenyl]fluorene; (1a-4)9, 9-bis[4-(2-(3-(meth)acryloyloxy-2-hydroxypropoxy) ethoxy)-3-phenylphenyl]fluorene, 9,9-bis[4-(2-(3-(methylphenyl)fluorene Acryloyloxy-2-hydroxypropoxy-propoxy-3-phenylphenyl 9,9-bis[(3-(meth)acryloyloxy-2-hydroxybenzoyl)fluorene] (oxypropoxy)C 2-4 Alkoxy-C 6-10 arylphenyl]fluorene, etc. Examples include:

[0072] 9,9-bis[(3-(meth)acryloyloxy-2-hydroxypropoxy)poly(3-(meth)acryloyloxy)-2-hydroxypropoxy) As the alkoxyphenyl]fluorenes, there are mentioned those in which the ring Z in the formula (1a) 1a and Ring Z 1b is a substituted or unsubstituted benzene ring, k=0, A 1a and A 1b C 2-4 Al The compound (1a-1) is a compound in which n1 and n2 are each 2 to 10. ) to (1a-4), and compounds in which n1 and n2 are 2 to 10, respectively. For example, (1a-5) 9,9-bis[4-(2-(2-(3-(meth)acryloyloxy)methyl]ethyl] [2-hydroxypropoxy)ethoxy)ethoxy)phenyl]fluorene, 9,9 -bis[4-(2-(2-(3-(meth)acryloyloxy-2-hydroxypropoxy] 9,9-bis[4-(2-(2- (2-(3-(meth)acryloyloxy-2-hydroxypropoxy)ethoxy)ethoxy 9,9-bis[(3-(meth)acryloyl)-2-(ethoxy)phenyl]fluorene, (hydroxy-2-hydroxypropoxy) di- or deca C 2-4 Alkoxyphenyl]ful (1a-6) 9,9-bis[4-(2-(2-(3-(meth)acryloyloxy) [(2-hydroxypropoxy)ethoxy)ethoxy)-3-methylphenyl]fluorene 9,9-bis[4-(2-(2-(3-(meth)acryloyloxy-2-hydroxybenzoyl) (Cipropoxy)propoxy)propoxy)-3-methylphenyl]fluorene, 9,9- Bis[4-(2-(2-(2-(3-(meth)acryloyloxy-2-hydroxypropyl] (ethoxy)ethoxy)ethoxy)ethoxy)-3-isopropylphenyl]fluorene, 9 ,9-bis[4-(2-(2-(3-(meth)acryloyloxy-2-hydroxypropyl] 9,9-(2,3-dimethylphenyl)ethoxy)ethoxy)-3,5-dimethylphenyl]fluorene, etc. Bis[(3-(meth)acryloyloxy-2-hydroxypropoxy)di- or deca-C 2-4 Alkoxy-mono or di C1-4 Alkylphenyl]fluorene; (1a-7) 9,9-bis[4-(2-(2-(3-(meth)acryloyloxy-2-hydroxypropyl] (3-cyclohexylphenyl)fluorene, 9,9- Bis[4-(2-(2-(3-(meth)acryloyloxy-2-hydroxypropoxy] )propoxy)propoxy)-3-cyclohexylphenyl]fluorene, 9,9-bis [4-(2-(2-(2-(3-(meth)acryloyloxy-2-hydroxypropoxy (C)ethoxy)ethoxy)ethoxy)-3-cyclohexylphenyl]fluorene, etc. 9,9-bis[(3-(meth)acryloyloxy-2-hydroxypropoxy)dimethylamino] Deka C 2-4 Alkoxy-C 5-10 cycloalkylphenyl]fluorene;(1a- 8) 9,9-bis[4-(2-(2-(3-(meth)acryloyloxy-2-hydroxy] (Cipropyloxy)ethoxy)ethoxy)-3-phenylphenyl]fluorene, 9,9-biphenyl s[4-(2-(2-(3-(meth)acryloyloxy-2-hydroxypropoxy) propoxy)propoxy)-3-phenylphenyl]fluorene, 9,9-bis[4-( 2-(2-(2-(3-(meth)acryloyloxy-2-hydroxypropoxy)ethoxy)ethoxy 9,9-bis[(ethoxy)ethoxy)ethoxy-3-phenylphenyl]fluorene, etc. (3-(meth)acryloyloxy-2-hydroxypropoxy)di- or deca-C 2-4 Alkoxy-C 6-10 arylphenyl]fluorene and the like.

[0073] 9,9-bis[(3-(meth)acryloyloxy-2-hydroxypropoxy)poly(3-(meth)acryloyloxy)-2-hydroxypropoxy) As the alkoxynaphthyl]fluorenes, there are mentioned those in which the ring Z in the formula (1a) 1a and Ring Z 1b is a substituted or unsubstituted naphthalene ring, k=0, A 1a and A 1b C 2-4 a alkylene group, compounds in which n1 and n2 are each 2 to 10, for example, (1a-9)9, 9-bis[6-(2-(2-(3-(meth)acryloyloxy-2-hydroxypropionyl) 9,9-bis[6-(2-(( 2-(3-(meth)acryloyloxy-2-hydroxypropoxy)propoxy)prop 9,9-bis[6-(2-(2-(2-(3-( Meth)acryloyloxy-2-hydroxypropoxy)ethoxy)ethoxy)ethoxy )-2-naphthyl]fluorene, 9,9-bis[5-(2-(2-(3-(meth)acryl (2-hydroxypropoxy)ethoxy)ethoxy)-1-naphthyl] 9,9-bis[(3-(meth)acryloyloxy-2-hydroxypropanol] Kisi) Di or Deca C 2-4 alkoxynaphthyl]fluorene and the like.

[0074] These epoxy (meth)acrylates can be used alone or in combination as molecular aggregates. A preferred epoxy (meth)acrylate is a compound represented by the formula (1a ) in the ring Z 1a and ring Z 1b is a benzene ring or a naphthalene ring, n1 and n2 are each 2 to 10, i.e., 9,9-bis[(3-(meth)acryloyl (2-hydroxypropoxy)polyalkoxyphenyl]fluorenes; -bis[(3-(meth)acryloyloxy-2-hydroxypropoxy)polyalkoxy] and sinaphthyl]fluorenes.

[0075] Among these epoxy (meth)acrylates, the above (1a-5) 9,9-bis[ 4-(2-(2-(3-(meth)acryloyloxy-2-hydroxypropoxy)ethoxy)ethoxy 9,9-bis[(3-(meth)acryloyl)-2-(ethoxy)phenyl]fluorene, (hydroxy-2-hydroxypropoxy) di- or deca C 2-4 Alkoxyphenyl]ful (1a-6) 9,9-bis[4-(2-(2-(3-(meth)acryloyloxy) [(2-hydroxypropoxy)ethoxy)ethoxy)-3-methylphenyl]fluorene 9,9-bis[(3-(meth)acryloyloxy-2-hydroxypropoxy]propanol, etc. ) Di or Deca C 2-4 Alkoxy-mono or di C 1-4 Alkylphenyl]fluorene (1a-8) 9,9-bis[4-(2-(2-(3-(meth)acryloyloxy- 2-Hydroxypropoxy)ethoxy)ethoxy)-3-phenylphenyl]fluorene 9,9-bis[(3-(meth)acryloyloxy-2-hydroxypropoxy) Di or Deca C 2-4 Alkoxy-C 6-10 arylphenyl]fluorene;(1a- 9) 9,9-bis[6-(2-(2-(3-(meth)acryloyloxy-2-hydroxy 9,9-bis[5-(2-naphthyl)-2-propoxyethoxyethoxy]fluorene (2-(2-(3-(meth)acryloyloxy-2-hydroxypropoxy)ethoxy 9,9-bis[(3-(meth)acryloyl)-2-ethoxy-1-naphthyl]fluorene, (hydroxy-2-hydroxypropoxy) di- or deca C 2-4 Alkoxynaphthyl]ful Orange is preferred.

[0076] Furthermore, among the epoxy (meth)acrylates, those having the formula (1a) in which Z 1a and ring Z 1b is a benzene ring, R 1a and R 1b is an alkyl group, m1 and m2 is 0 to 2, that is, the (1a-5) 9,9-bis[4-(2-(2-( 3-(meth)acryloyloxy-2-hydroxypropoxy)ethoxy)ethoxy)furan 9,9-bis[(3-(meth)acryloyloxy-2-hydroxyphenyl]fluorene, etc. (Hydroxypropoxy) Di- or Deca C 2-4 Alkoxyphenyl]fluorene; (1a-6 )9,9-bis[4-(2-(2-(3-(meth)acryloyloxy-2-hydroxy 9,9-biphenyl]fluorene, such as 9,9-biphenyl (propoxy)ethoxy)ethoxy)-3-methylphenyl]fluorene S[(3-(meth)acryloyloxy-2-hydroxypropoxy)di- or dec-C2 -4 Alkoxy-mono or di C 1-4 Alkylphenyl]fluorene is preferred.

[0077] The ratio of the epoxy (meth)acrylate represented by the formula (1a) is It may be 50 to 100 mol % of the epoxy (meth)acrylate used, and preferably 70 to 100 mol%, more preferably 80 to 100 mol%, and even more preferably 90 to 10 0 mol %, and most preferably 100 mol %.

[0078] [Method for producing epoxy (meth)acrylate] The method for producing the epoxy (meth)acrylate represented by the formula (1) is as follows: As long as the number of added aryl groups, i.e., n1+n2, can be adjusted within a predetermined range, there is no particular limitation. In particular, the epoxy (meth)acrylate represented by the formula (1a) can be used. The method for producing the compound (I) may be, for example, a method for producing the compound (I) by reacting an epoxy compound represented by the following formula (3) with (meth)acrylic acid The epoxy compound represented by the formula (3) may be reacted with the epoxy compound represented by the formula (3). The compound can be produced by the method described in JP-A-2009-155256, for example.

[0079] [ka]

[0080] (In the formula, ring Z 1a and ring Z 1b , A 1a and A 1b , n1 and n2, R 1a and R 1b , m1 and m2, R 4 , k is the same as above)

[0081] In addition, a first hydroxy compound represented by the following formula (4) and glycidyl (meth)acrylate Method (B) of reacting a hydroxypropyl acrylate with a hydroxypropyl acrylate, for example, the method described in JP-A-2004-83855 It may also be law.

[0082] [ka]

[0083] (In the formula, ring Z 1a and ring Z 1b , A 1a and A 1b , n1 and n2, R1a and R 1b , m1 and m2, R 4 , k is the same as above)

[0084] In view of reactivity, the method (A) is usually used for preparation. The epoxy compound represented by the formula (3) used in the above may be a commercially available product, or may be a commonly used product. For example, a method of reacting a first hydroxy compound represented by the formula (4) with epichlorohydrin It is prepared by reacting it with an epihalohydrin such as bromohydrin or epibromohydrin. Therefore, the epoxy (meth)acrylate represented by the formula (1a) may be produced by the method (A In either case of preparation by the method (A) or (B), the first compound represented by the formula (4) The number of oxyalkylene groups added to the hydroxy compound (n1 + n2) is controlled within a predetermined range. As a result, the epoxy compound represented by the formula (3) and the epoxy compound represented by the formula (1a) can be The number of oxyalkylene groups added (n1 + n2) in the epoxy (meth)acrylate was adjusted. In addition, the epoxy compound represented by the formula (3) and the epoxy compound represented by the formula (4) may be The first hydroxy compounds may each be a molecular aggregate, and each oxyal The number of added alkylene groups (n1+n2) is also determined by the epoxy(meth)acrylate represented by the formula (1a). As with the carboxylate, it may be the average value of a molecular aggregate.

[0085] (First hydroxy compound represented by the formula (4)) In the formula (4), ring Z 1a and ring Z 1b , A 1a and A 1b , n1 and n 2. R 1a and R 1b , m1 and m2, R 2aand R 2b , R 4 , k for each The preferred embodiments are the same as those described above. Examples of the hydroxy compound include epoxy(meth)acrylates represented by the formula (1a) above. The hydroxylation corresponding to the compounds (1a-1) to (1a-9) shown as representative examples of the hydroxylate The compound, i.e., the 3-(meth)acryloyloxy-2-hydroxypropyl group is converted into a hydrogen atom. These compounds may be used alone or in combination of two or more. The compound may be contained as a molecular aggregate.

[0086] The first hydroxy compound represented by the formula (4) is not particularly limited, and a commercially available product may be used. A conventional method may be used, for example, by reacting a second hydroxy compound represented by the following formula (5) with the The oxyalkylene group OA in formula (4) 1a and O.A. 1b The corresponding alkylene Alternatively, the compound may be prepared by reacting the compound with an alkylene oxide or an alkylene carbonate. An example of the manufacturing method is the method described in Patent Document 5 (JP 2017-186513 A). is available.

[0087] [ka]

[0088] (wherein n3 and n4 each represent 0 or 1; ring Z 1a and ring Z 1b , A 1 a and A 1b , R 1a and R 1b , m1 and m2, R 4 , k is the same as above)

[0089] (Method (A)) The epoxy compound represented by the formula (3) and the epoxy compound represented by the formula (1a) by the method (A) Specific methods for preparing the epoxy (meth)acrylates are described in Patent Documents 5 (JP 2017-186513 A) and the like can be used.

[0090] In the present invention, the number of oxyalkylene groups added (n1+n2) is adjusted to a predetermined range. Therefore, it has a relatively low viscosity and is easy to handle. The viscosity of the epoxy (meth)acrylate represented by 1a) is 5000 to 150,000 mPa The viscosity can be selected from a range of, for example, 10,000 to 60,000 mPa·s, preferably 2 0,000 to 50,000 mPa·s, more preferably 30,000 to 45,000 mPa·s The viscosity is most preferably 35,000 to 40,000 mPa·s.

[0091] In this specification and claims, the viscosity is TV-22 at 25°C. Measurement was performed using a viscometer (cone plate type, "TVE-22L" manufactured by Toki Sangyo Co., Ltd.) Optional rotors (01:1°34' x R24, 07:3° x R7.7) are available depending on viscosity. Measurement can be performed at 1 to 20 rpm (selected depending on viscosity).

[0092] [Curable composition] The epoxy (meth)acrylate may be used alone, but may also be used in combination with an ultraviolet absorber, a polymerizer, or the like. It may be mixed with other ingredients such as initiators, other polymerizable compounds, and solvents to form a curable composition. stomach.

[0093] (ultraviolet absorber) The curable composition, which is one of the preferred embodiments of the present invention, may contain an ultraviolet absorber. As the ultraviolet absorber, a conventional ultraviolet absorber can be used.

[0094] The curable composition containing the ultraviolet absorber has excellent light resistance, and as will be described later, It is effective to laminate it on the surface to function as a polarizer protective film. The luminescent film blocks ultraviolet light with wavelengths of 380 nm or less to prevent the deterioration of iodine caused by ultraviolet light. Specifically, the spectral transmittance at 380 nm must be 10% or less. To satisfy these demands, UVA rays, which are 320 to 400 nm, are used. Addition of an ultraviolet absorber having a maximum absorption wavelength is effective. Examples of suitable compounds include oxybenzophenone compounds, benzotriazole compounds, and triazine compounds. Examples include fluorine-based compounds.

[0095] Examples of oxybenzophenone compounds include 2,4-dihydroxybenzophenone. 2-Hydroxy-4-methoxybenzophenone, 2-hydroxy-4-pentyloxy benzophenone, 2-hydroxy-4-octyloxybenzophenone, 2-hydroxy Hydroxy C, such as 4-octyloxy-4'-methoxybenzophenone 1-18 a 2-Hydroxy-4-cyclohexyloxybenzophenone; 2-Hydroxy-4-cyclohexyloxybenzophenone Which hydroxycycloalkyloxybenzophenone; 2-hydroxy-4-octyloxy Hydroxy C such as 4'-chlorobenzophenone 1-18 Alkoxyhalobenzof These oxybenzophenone compounds may be used alone or in combination of two or more. They can be used in combination. Commercially available products include ADEKA Corporation's ADK STAB 1413, Chimassorb 81 from BASF Japan Ltd. can be used. In view of the ease of preparing a uniform composition, 2-hydroxy-4-octyloxybenzophenone is preferred. Oxybenzophenone compounds having a linear alkyl group with 2 or more carbon atoms, such as benzophenone, are preferred. The number of carbon atoms in the linear alkyl group having 2 or more carbon atoms can be selected from the range of about 2 to 18, and preferred The ranges are as follows: 3-16, 4-14, 5-12, 6-10, with the most preferred being Preferably 7 to 9.

[0096] In the present specification and claims, the term "straight-chain alkyl group" refers to a branched-chain alkyl group. The straight-chain alkyl groups contained therein (e.g., the ethyl group in the 2-ethylhexyl group, the n-butyl It is used in a sense that also includes groups.

[0097] Examples of benzotriazole compounds include 2-(2H-benzotriazole-2 -yl)-4-methyl-phenol, 2-(2H-benzotriazol-2-yl)-4 -t-Butyl-phenol, 2-(2H-benzotriazol-2-yl)-4-(1, 1,3,3-Tetramethylbutyl)-phenol, 2-(2H-benzotriazole-2 -yl)-4-methyl-6-dodecyl-phenol, etc. -C 1-18 Alkyl-phenol; 2-(2H-benzotriazol-2-yl)-4 ,6-bis(1-phenylethyl)phenol and other benzotriazol-2-yl-bis(benzotriazol-2-yl)phenols S(phenyl C 1-18 2-(2H-benzotriazole-2 -yl)-4,6-bis(1-methyl-1-phenylethyl)-phenol, Triazol-2-yl-bis(C 1-18 Alkyl-phenyl C 1-18 alkyl)- Phenol; 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenyl)- benzophenone, such as benzophenone, ... Triazol-2-yl-(C 1-18 Alkyl-phenyl C 1-18 Alkyl)-C1 -18 Alkyl-phenol; 2-(5-chloro-2H-benzotriazol-2-yl Halobenzotriazoles such as )-6-(1,1-dimethylethyl)-4-methyl-phenol Zol-2-yl-C 1-18 Alkyl-phenol; 2,2'-methylenebis[4-( 1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl) phenol], 2,2'-methylene-bis[6-(2H-benzotriazol-2-yl )-4-(1,1,3,3-tetramethylbutyl)-phenol] and other methylene-bis (benzotriazol-2-yl-C 1-18 Alkyl-phenol; 2-(2-hydroxy (3-α-cumyl-5-dodecylphenyl)-2H-benzotriazole -(hydroxy-α-cumyl-5-C 1-18 Alkyl-phenyl)-2H-benzotriazole Azole; Octyl-3-[3-(1,1-dimethylethyl)-4-hydroxy-5-( 2H-benzotriazol-2-yl)phenyl]propionate, octyl-3-[3 -tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole- 2-ethylhexyl-3-[3-tert-butyl]propionate 4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl C such as propionate 1-18 Alkyl-[C 1-18 Alkyl-hydroxy-( (halo)-2H-benzotriazol-2-yl)phenyl]C 2-4 Acylates, etc. Examples include:

[0098] These benzotriazole compounds can be used alone or in combination. Commercially available benzotriazole compounds include Chinubi, manufactured by BASF Japan Ltd. Ng P, Tinuvin 234, Tinuvin 326, Tinuvin 329, Tinuvin 360, Tinuvin 5 71, Tinuvin 99-2, Tinuvin 213, Tinuvin 900, Tinuvin 928, Inc. ADEKA's ADK STAB LA-31, Everlight Chemical's Ev Eversorb89, Eversorb109, EversorbBL1A, etc. are available. do.

[0099] Among these benzotriazole compounds, octyl benzoate is preferred because it is easy to prepare a uniform composition. ethyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzo[a]thiazolinone] Straight-chain alkyl groups with 2 or more carbon atoms, such as triazol-2-yl)phenyl]propionate Benzotriazole compounds having a straight-chain alkyl group with two or more carbon atoms are preferred. Prime numbers can be selected from the range of 2 to 18, with the preferred range being 3 to 1. It is preferably 6, 4 to 14, 5 to 12, or 6 to 10, and most preferably 7 to 9.

[0100] Examples of triazine compounds include 2-(4-hexyloxy-2-hydroxybenzoates). (phenyl)-4,6-diphenyl-1,3,5-triazine, 2-[4-[(2-hydroxyphenyl) [3-(2'-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis (hydroxy-C) 1- 18 Alkoxy-hydroxyphenyl)bis(diC 1-18 alkyl-phenyl)-1, 3,5-Triazine; 2,4-bis(2-hydroxy-4-butoxy-phenyl)-6 Bis(hydroxy)-(2,4-dibutoxyphenyl)-1,3,5-triazine -C 1-18 Alkoxy-phenyl)-(diC 1-18 Alkoxy-phenyl)-1,3 ,5-Triazine; 2,4,6-Tris(2-hydroxy-4-hexyloxy-3-methyl Tris(hydroxy-C)-1,3,5-triazine, etc. 1-18 Arco Kishi-C 1-18 alkyl-phenyl)-1,3,5-triazine. These triazine compounds can be used alone or in combination. BASF Japan Ltd.'s Tinuvin 405 and Tinuvin 460, and ADEK Corporation Adeka STAB CA-F70 etc. can be used. From the viewpoint of ease of use, 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylfuran) Oxygen having a linear alkyl group with two or more carbon atoms, such as (phenyl)-1,3,5-triazine Benzophenone compounds are preferred. The linear alkyl group having 2 or more carbon atoms has about 2 to 18 carbon atoms. The preferred ranges are 3-16, 4-14, 5 Preferably, the number of carbon atoms is 1 to 12, 6 to 10, and most preferably 7 to 9.

[0101] These ultraviolet absorbers can be used alone or in combination. Among infrared absorbers, benzotriazole compounds are preferred because they are easy to prepare uniform compositions. From this viewpoint, benzotriazole compounds having a linear alkyl group having 4 or more carbon atoms are more preferred. Among them, C 4-12 Alkyl-[C 2-16 Alkyl-hydroxy-(halo- 2H-benzotriazol-2-yl)phenyl]C 2-4 Acylates are preferred, C4 -10 Alkyl-[Branched Chain C 3-12 Alkyl-hydroxy-(halo-2H-benzotriazole) (azol-2-yl)phenyl]C 3-4 Acylates are particularly preferred.

[0102] The type and amount of UV absorber to be added depend on the absorption spectrum, molar absorption coefficient, and The content can be set in an optimal range depending on the compatibility with the curable resin composition. The total light transmittance (JIS K7361) of the cured film was measured at 380 nm. Light transmittance (JIS K7105), haze (JIS K7136), yellowness index (YI) ( It can be determined based on the evaluation results of JIS K7373. It is not limited to the following values. However, the total light transmittance is preferably 85% or more, more preferably 88% or more, and more preferably 89% or more. The lower the spectral transmittance at 380 nm, the more preferable it is. The haze is preferably 0% or less, more preferably 10% or less, and particularly preferably 8% or less. The lower the value, the more preferable it is, for example, 1% or less is more preferable. The maximum absorption wavelength should be closer to 380 nm, but if it is closer to 400 nm, it will turn yellow. This is undesirable as it will cause the color to become stronger. If the molar absorption coefficient at 380 nm is too low, the amount added will be too large and the insoluble matter will be This is undesirable as it can cause noise and bleed out.

[0103] The proportion of the ultraviolet absorber is determined based on the total amount of (meth)acryloyl group-containing components in the curable composition (e.g., For example, the epoxy (meth)acrylate represented by the formula (1) and other polymerizable compounds described below For example, 0.1 to 10 parts by mass, preferably 0.1 to 10 parts by mass, per 100 parts by mass (total amount of compounds, etc.). 5 to 8 parts by mass, more preferably 0.8 to 5 parts by mass, and most preferably 1 to 3 parts by mass. In particular, even a small amount of addition can improve UV blocking ability, and has an effect on various properties such as optical and mechanical properties. From the viewpoint of excellence, the proportion of the ultraviolet absorber is preferably 1 / 2 or more of the (meth)acryloyl group-containing component in the curable composition. For example, 0.6 to 3 parts by mass, preferably 0.7 to 2 parts by mass, more preferably 0.6 to 3 parts by mass, based on the total amount of the components. or 0.8 to 1.5 parts by mass, more preferably 0.9 to 1.2 parts by mass, most preferably 0 If the proportion of the ultraviolet absorber is too low, the effect of improving light resistance will not be achieved. On the other hand, if the amount is too large, the mechanical properties of the cured product may be reduced.

[0104] (Polymerization initiator) The curable composition, which is one of the preferred embodiments of the present invention, contains a thermal polymerization initiator and / or a photopolymerizable The thermal polymerization initiator may contain an initiator. Examples of the thermal polymerization initiator include organic peroxides and azide compounds. As for organic peroxides, dialkyl peroxides such as di-t-butyl peroxide are diacyl peroxides such as lauroyl peroxide and benzoyl peroxide; Peroxides such as t-butyl hydroperoxide, cumene hydroperoxide, and t-butyl peracetate Acids (or peresters); Ketone peroxides; Peroxycarbonates; Per Examples of azo compounds include 2,2-azobis(isobutyl) azonitrile compounds such as azonitrile; azoamide compounds; azoamidine compounds These thermal polymerization initiators can be used alone or in combination of two or more.

[0105] As a photopolymerization initiator (or photoradical polymerization initiator), benzoin, etc. Benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether Benzoin ether, benzoin isobutyl ether, benzoin phenyl ether, etc. Alkyl ethers; acetophenone, 3-hydroxyacetophenone, 2,2-dimeth 2-hydroxy-2-methyl-1-phenyl propan-1-one, 1-hydroxycyclohexyl phenyl ketone, 1-[4-(2 -hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1 -one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl (I)-benzyl]-phenyl}-2-methyl-propan-1-one, 2,2-dimethoxy -1,2-diphenylethan-1-one and other acetophenones; 2-methyl-1-[4 -(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2- Dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-dimethyl Amino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl) -butan-1-one and other aminoacetophenones; anthraquinone, anthraquinone- 2-sulfonates, anthraquinones such as 2-ethylanthraquinone; thioxanthone , isopropoxychlorothioxanthone, 2-chlorothioxanthone, 2,4-dimethyl Thioxanthones such as xanthone; acetophenone dimethyl ketal, benzyl dimethyl ketals such as benzophenone, 4-hydroxybenzophenone, 4,4 '-Dihydroxybenzophenone, 4,4'-dichlorobenzophenone, 3-methylbenzophenone Benzophenones such as benzophenone and 4-phenylbenzophenone; 2-(o-chlorobenzophenone) (phenyl)-4,5-diphenylimidazole dimer, 2-(2,4-dimethoxyphenyl 2,4,5-Triarylimidazoline, such as 2,4,5-triarylimidazoline, 4,5-diphenylimidazole dimer, Dimers; Xanthones; 2,4,6-Trihalomethyltriazines; 9-Phenylalanine acridine derivatives such as cridine and 1,7-bis(9,9'-acridinyl)heptane; Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2, 6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, Acylphosphite, such as 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide These photopolymerization initiators may be used alone or in combination of two or more. Can be used in combination.

[0106] When the curable composition contains an ultraviolet absorber that absorbs ultraviolet light with a wavelength shorter than 400 nm, In order to efficiently use visible light for photo-curing, the photoinitiator should be switched to a wavelength of 400 to 450 nm. Photopolymerization initiators with a threshold (or maximum absorption wavelength) It is preferable that the photopolymerization initiator contains a photopolymerization initiator having an absorption wavelength in the long wavelength region. Photopolymerization initiator with a threshold below 400 nm (having an absorption wavelength in the short wavelength region) A combination with a photopolymerization initiator is particularly preferred.

[0107] As the photopolymerization initiator having an absorption wavelength in the long wavelength region (long wavelength photopolymerization initiator), the above-mentioned photopolymerization initiator Among the initiators, aminoacetophenones (α-aminoacetophenone compounds), acyl Phosphine oxides and the like are listed. Commercially available aminoacetophenones include, for example: For example, BASF Japan Ltd.'s IRGACURE369, 379, and 907. Commercially available acylphosphine oxides include those from BASF Japan IRGACURE 819, 1800, DAROCUR TPO, etc. from Co., Ltd. are available. Among these, bis(2,4,6-trimethylbenzoyl)-phenylphosphine Acylphosphine oxide compounds such as acylphosphine oxides are preferred.

[0108] As the photopolymerization initiator having an absorption wavelength in the short wavelength region (short wavelength photopolymerization initiator), Among polymerization initiators, photopolymerization initiators other than aminoacetophenones and acylphosphine oxides Among the photopolymerization initiators, 1-hydroxycyclohexylphenyl ether is preferred. Acetophenones such as phenylalanine ketone are preferred. Commercially available acetophenones include, for example, For example, IRGACURE184 from BASF Japan Ltd. can be used.

[0109] The proportion of polymerization initiator (thermal and / or photopolymerization initiator) is determined by the (meth)acrylic acid in the curable composition. The total amount of the acryloyl group-containing components (for example, the epoxy (meth) acrylate represented by the formula (1)) For example, 0. 1 to 15 parts by mass, preferably 0.5 to 10 parts by mass, more preferably 1 to 8 parts by mass, most preferably The amount is preferably 2 to 5 parts by mass. Among these polymerization initiators, at least a photopolymerization initiator is preferably used. It is preferred to include

[0110] When a short wavelength photopolymerization initiator and a long wavelength photopolymerization initiator are combined, the long wavelength photopolymerization initiator The ratio may be 1 part by mass or more relative to 100 parts by mass of the short wavelength photopolymerization initiator, for example Preferably, the amount is 1 to 200 parts by mass, more preferably 5 to 150 parts by mass, and even more preferably 10 to 100 parts by mass. parts by mass, and most preferably 20 to 50 parts by mass. However, if the curable composition contains an ultraviolet absorber, the photocurability may be reduced.

[0111] The photopolymerization initiator may be combined with a photosensitizer. The photosensitizer may be a tertiary amine. The tertiary amine may be a conventional photosensitizer such as trialkylamine; Triethanolamine and other trialkanolamines; N,N-dimethylaminobenzoic acid Dialkylaminobenzoates such as ethyl, N,N-dimethylaminobenzoate amyl ester; 4,4-bis(dimethylamino)benzophenone, 4,4-bis(diethyl Bis(dialkylamino)benzophenones such as 4-(dimethylamino)benzophenone; 4-methoxy-4'-dimethylaminobenzophenone, These photosensitizers may be used alone or in combination with other photosensitizers such as dialkylaminobenzophenones. Two or more types can be used in combination. The curable composition absorbs ultraviolet light with a wavelength shorter than 400 nm. When the photosensitizer contains an ultraviolet absorber having an absorption wavelength of 400 to 450 nm, the photosensitizer Agents are preferred.

[0112] The ratio of the photosensitizer is, for example, 1 to 200 parts by mass relative to 100 parts by mass of the photopolymerization initiator. The amount is preferably 5 to 150 parts by mass, and more preferably 10 to 100 parts by mass.

[0113] (Other polymerizable compounds) The curable composition, which is one of the preferred embodiments of the present invention, further contains one or more polymerized groups in the molecule. The composition may contain a polymerizable compound having a reactive functional group, which can improve sensitivity (or curability). The polymerizable compound may be used to improve the flowability, chemical resistance, heat resistance, mechanical strength, etc. The compound may be a polymerizable compound having a vinyl group, but may also be a polymerizable compound having a (meth)acryloyl group. These are often mono- or polyfunctional (meth)acrylates that react with the acrylate group.

[0114] Monofunctional (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, alkyl (meth)acrylates such as butyl (meth)acrylate; hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate; alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate; Cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate; phenyl aryl(meth)acrylates such as phenyl(meth)acrylate; phenoxyethyl(meth)acrylate; Aryloxyalkyl (meth)acrylates such as benzyl (meth)acrylate; ) acrylate and other aralkyl (meth)acrylates; phenoxyethoxyethyl (meth)acrylate; Aryloxy((poly)alkoxy)alkyl(meth)acrylates such as aryloxy((poly)alkoxy)alkyl(meth)acrylates acrylate; alkylaryloxy acrylate such as nonylphenoxyethyl (meth)acrylate Nonylphenoxy(poly)ethoxyethyl(meth)acrylate Alkylaryloxy (poly)alkoxyalkyl (meth)acrylates, etc. ; aryl aryl such as 2-(o-phenylphenoxy)ethyl (meth)acrylate Oxyalkyl (meth)acrylate; Phenylphenoxy (poly)ethoxyethyl (meth)acrylate arylaryloxy (poly)alkoxyalkyl (meth)acrylates, etc. Acrylates; alkylthio(meth)acrylates such as methylthio(meth)acrylate ;Arylthio(meth)acrylates such as phenylthio(meth)acrylate;Benzyl Aralkylthio(meth)acrylates such as phenylthio(meth)acrylate Arylthioalkyl (meth)acrylates such as ethyl (meth)acrylate; N,N -N,N-dialkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate amide; mono(meth)acrylate of ethylene oxide adduct of bisphenol A, etc. Mono(meth)acrylates of bisphenols or alkylene oxide adducts thereof; (meth)acryloyloxymethylfluorene and other fluorene-based compounds ) acrylates, etc.

[0115] Multifunctional (meth)acrylates include difunctional (meth)acrylates, trifunctional or higher ( Difunctional (meth)acrylates include ethylene glycol, Lithium di(meth)acrylate, butanediol di(meth)acrylate, dipropylene (Poly)C such as ethylene glycol di(meth)acrylate 2-4 Alkylene glycol di( meth)acrylate; bisphenol A (or its alkylene oxide adduct) di( meth)acrylate, 9,9-bis[4-(2-(meth)acryloyloxy(poly)ester (Meth)acrylates with trifunctional or higher functionality include (meth)acrylates with trifunctional or higher functionality. Examples include glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, Acrylate, Pentaerythritol Tri(meth)acrylate, Pentaerythritol Tetra(meth)acrylate, Dipentaerythritol penta(meth)acrylate, Di Tri- or hexaol tri-acrylates such as pentaerythritol hexa(meth)acrylate or hexa(meth)acrylate]; urethane(meth)acrylate; fluorene skeleton Tri- to hexafunctional (meth)acrylates [e.g., 9,9-bis[4-(2-(meth)acrylate] (p) acryloyloxy (poly) ethoxy) phenyl] fluorene, etc. do.

[0116] These monofunctional and polyfunctional (meth)acrylates may be used alone or in combination of two or more. They can also be used in combination.

[0117] The ratio of these polymerizable compounds is the epoxy (meth)acrylate represented by the formula (1). For example, the amount can be selected from the range of about 0 to 50 parts by mass relative to 100 parts by mass of the compound, and preferably 0 up to 30 parts by mass, more preferably 0 to 20 parts by mass, and most preferably 0 to 10 parts by mass .

[0118] (Other additives) The curable composition may contain a solvent, if necessary. There is no particular limitation, and di-acetone such as diisopropyl ketone and methyl isobutyl ketone may be used. Cyclic ketones such as cyclohexanone, diethyl ether, diisopropyl ether Chain ethers such as methyl ether; cyclic ethers such as tetrahydrofuran and dioxane; Cellosolve acetate, propylene glycol monomethyl ether acetate, etc. alkylene glycol monoalkyl ether acetates; esters such as ethyl acetate; Nitriles such as acetonitrile; dimethylformamide, dimethylacetamide, etc. Amides; sulfoxides; aliphatic hydrocarbons such as hexane and heptane; cyclohexane Alicyclic hydrocarbons such as toluene, xylene, ethylbenzene, and other aromatic hydrocarbons; Examples include halogenated hydrocarbons such as methylene chloride, chloroform, and 1,2-dichloroethane. These solvents can be used alone or in combination as a mixed solvent. It is also possible.

[0119] Furthermore, the curable composition may contain conventional additives, such as Colorants, stabilizers, polymerization inhibitors, fillers, antistatic agents, flame retardants, surfactants, plasticizers, defoamers The stabilizer may contain a heat stabilizer, an antioxidant, a coupling agent, etc. These additives may be used alone or in combination of two or more. The proportion of the additives is the epoxy (meth)acrylate represented by the formula (1) and other polymers. For example, 0.1 to 20 parts by mass, preferably 0.5 parts by mass, based on 100 parts by mass of the total amount of the synthetic compound. The amount is preferably from 1 to 10 parts by mass, and more preferably from 1 to 5 parts by mass.

[0120] [Cured product] The curable composition can be easily cured by applying active energy (active energy rays). The activation energy is preferably heat energy and / or light energy. The light energy can be selected appropriately depending on the purpose. Examples include:

[0121] When thermal energy is used, the heating temperature is, for example, 50 to 250°C, preferably The heating temperature is preferably 60 to 120° C., more preferably 70 to 100° C. The heating time is, for example, 5 minutes to The time is 12 hours, preferably 10 minutes to 8 hours, and more preferably 30 minutes to 4 hours.

[0122] When using light energy such as ultraviolet light, the amount of light irradiation energy varies depending on the application. can be appropriately selected, for example, 50 to 10,000 mJ / cm 2 , preferably 70 to 8000 mJ / cm 2 , and more preferably 100 to 5000 mJ / cm 2 , most preferably 300 to 3 000mJ / cm 2 The light source is a deep UV lamp, a low-pressure mercury lamp, or a high-pressure Mercury lamps, ultra-high pressure mercury lamps, halogen lamps, helium-cadmium lasers and exhausts A laser light source such as a simmer laser can be used.

[0123] Even when curing by light irradiation, a baking treatment is required to improve reactivity. The temperature and time of the heat treatment may be as follows: The same as the case of using thermal energy. The curing may be carried out in an air atmosphere or an inert gas atmosphere, under normal pressure, under pressure or under reduced pressure. Examples of inert gas atmospheres that may be used under pressure include nitrogen, helium, argon, etc. A rare gas atmosphere is an example.

[0124] The cured product, which is one of the preferred embodiments of the present invention, is a polymer having an oxyalkylene group introduced therein, which has high flexibility. Despite being made of acrylic, it has surprisingly high hardness and has the contradictory properties of high hardness and flexibility. The reason for this is unclear, but the oxyalkylene The hydrogen bond is formed between the hydroxyl group of the epoxy (meth)acrylate. Usually, when an oxyalkylene group is introduced, the cured product has a structure that is easily bent. The flexibility of the cured product tends to be greatly improved, probably because the crosslink density is reduced. Therefore, the hardness, which is a property that contradicts flexibility, is significantly reduced. ) and epoxy (meth)acrylate has a hydroxyl group ((meth)acrylate) on the side chain. hydroxyl group adjacent to the hydroxyl group), and the number of oxyalkylene groups added (n1+ n2) is adjusted to a predetermined range, the oxyalkylene group is relatively uniform even in the cured product. The oxygen atom of the oxyalkylene group and the hydroxyl group form a hydrogen bond. It is believed that this facilitates the formation of pseudo-crosslinking points, thereby improving the crosslink density and hardness. Moreover, as the crosslink density and hardness increase, the initial flexibility is generally lost. In one preferred embodiment of the present invention, the cured product has a relatively low hydrogen bond energy. When an external force greater than this acts, the bond is easily broken (the cross-link density decreases), and the oxyalkylene The flexibility derived from the hydroxyl groups appears, and when the external force is removed, new hydrogen bonds are formed, resulting in high hardness. It is assumed that this will achieve both strength and flexibility.

[0125] [Optical film] The following describes an optical film (a cured product of the curable composition) which is one of the preferred embodiments of the present invention. An embodiment of a method for producing the formed cured film will be described.

[0126] FIG. 1 is a schematic diagram of a manufacturing process for an optical film according to a preferred embodiment of the present invention. Since the curable composition that is the raw material for the optical film is liquid, it is possible to use a known coating device. As shown in FIG. 1, the curable composition 3 is wound on a support film unwound from an unwinding device 1. The cast curable composition is applied onto the film 2 in the form of a film from a coating head 4. The product 3 is cured by irradiating a predetermined amount of light from the ultraviolet irradiation device 5, and is a cured film-like cured product. The (cured film) 7 is peeled off from the support film 2 by the winding device 6, and the cured film is wound It is wound up at position 8.

[0127] The method of casting and applying the curable composition is one that can be used in the technical field to which the present technology belongs. There are no particular limitations if there is a coating method, such as bar coating, knife coating, or roll coating. coating method, blade coating method, die coating method, microgravure coating method coating method, comma coating method, slot die coating method, lip coating method Methods such as the casting method and solution casting method can be used.

[0128] The curable composition must be in a liquid state, but a solvent may be used as a diluent to adjust the viscosity, etc. For example, the ultraviolet absorber can be added by adding methanol. , ethanol, butanol and other alcohols, methylene chloride, methyl acetate, acetonitrile A solution is prepared by dissolving an ultraviolet absorber in an organic solvent such as ethanol or dioxolane or a mixture of these solvents. However, in this case, the solvent volatilization process takes time. This reduces production efficiency, and residual solvents may remain inside the cured film, which can affect the properties of the formed film. The content of solvent in the applied curable composition should be 5% by mass or less. It is particularly preferred to use compositions that are substantially solvent-free. Preferably, a solvent-free composition is used.

[0129] The support film has surface smoothness, wettability with the curable composition, releasability of the cured film, The material is selected based on its transportability. The support film is made of polyester resin, poly Olefin resin, vinyl chloride resin, acetyl cellulose resin, acrylic resin, Vinyl fluoride resin, polycarbonate resin, polyamide resin, polyethersulfone Among these, films of smooth surface can be used. Polyester resins, especially polyethylene terephthalate, are excellent in terms of mechanical properties and have a good balance of other properties. Phthalate (PET) film is preferred.

[0130] The thickness (average thickness) of the support film is not particularly limited, but is, for example, 10 to 400 μm. is.

[0131] The edges of the cured film may bend due to wrinkles or shrinkage during curing, so be careful not to slip. Alternatively, the film may be cut and removed to an appropriate width using a cutter.

[0132] The pencil hardness of the optical film (cured film) which is one of the preferred embodiments of the present invention is, for example, The pencil hardness is preferably 1H or more, more preferably 2H or more, and even more preferably 3H or more. However, when used as a cover sheet, there is a risk that protective functions such as abrasion resistance may be reduced. In this specification and claims, pencil hardness is determined in accordance with JIS K5600-5-4. In detail, it can be measured by the method described in the Examples below.

[0133] The optical film has excellent folding stability and is less likely to develop creases or creases. The bending stability of the optical film is, for example, 2 mm or less, preferably 1 mm or less, and more preferably If the bending stability is too low, the sheet may not be able to be folded for a long time. If left unattended, deformation such as bending may occur. In this range, the bending stability is as described in Patent Document 4 (JP 2019-051718 A). It can be evaluated by the indicated method, and in detail, it can be measured by the method described in the examples below.

[0134] The optical film also has excellent bending durability, and no creases or creases are observed even after repeated bending. The optical film has a bending durability of, for example, 100,000 times or more. It may be or more, preferably 300,000 times or more, and more preferably 500,000 times or more. If the bending durability is too low, repeated bending may cause creases or breakage. In the present specification and claims, the bending durability is the same as that described in the examples below. It can be measured by the following method.

[0135] The optical film has excellent transparency, with a total light transmittance of 80%. For example, 80 to 100%, preferably 83 to 99%, and more preferably The content of the ultraviolet absorber in the optical film is 85 to 98%, and most preferably 88 to 95%. When the composition contains the compound, the total light transmittance may be 85% or more, preferably 87% or more, Preferably, it is 88% or more, and most preferably, it is 89% or more. Within the required range, the total light transmittance can be measured in accordance with JIS K7361-1. can be measured by the method described in the Examples below.

[0136] The optical film may have a spectral transmittance of 50% or more at a wavelength of 380 nm. Preferably, the ratio is 50 to 100%, more preferably 60 to 95%, even more preferably 70 to 90%, and most preferably When the optical film contains an ultraviolet absorber, the spectral transmittance is 80 to 85%. The transmittance may be 50% or less, for example 30% or less, preferably 10% or less, and more preferably Preferably, it is 8% or less. In the present specification and claims, the spectral transmittance can be measured by the method described in the Examples below.

[0137] The yellowness index (YI) of the optical film may be 10 or less, for example, 0.1 to 10. Preferably, it is 0.3 to 8, more preferably 0.5 to 5, even more preferably 1 to 3.5, and most preferably Preferably, the yellowness index is 1.5 to 2.5. When the optical film contains an ultraviolet absorber, is, for example, 10 or less, preferably 8 or less, more preferably 7 or less, and most preferably 6 or less. In this specification and claims, the yellowness index is determined according to JIS K737 3, and more specifically, can be measured by the method described in the Examples below.

[0138] The haze of the optical film may be 10% or less, for example, 0.1 to 10%, preferably Preferably 0.2 to 5%, more preferably 0.3 to 3%, even more preferably 0.5 to 2%, and most preferably The content is preferably 0.7 to 1.5%. The noise should be 5% or less, preferably 3% or less, more preferably 1% or less, and most preferably 0. In this specification and claims, the haze is determined based on JIS K 7136, and in detail, can be measured by the method described in the Examples below.

[0139] The refractive index of the optical film at 20° C. and a wavelength of 589 nm is, for example, in the range of 1.6 or less. For example, it can be selected from 1.52 to 1.6, preferably 1.53 to 1.59, and more preferably is 1.54 to 1.585, more preferably 1.55 to 1.58, and most preferably 1.56 In this specification and claims, the refractive index is the same as that of the multi-wavelength It can be measured using a Abbe refractometer, and more specifically, it can be measured by the method described in the examples below.

[0140] The optical film has a small retardation (birefringence) and does not impair the visibility of the image display device. The in-plane retardation (or front retardation) Ro of the optical film is At a thickness of 50 μm, the thickness is 0 to 10 nm, and the preferred range is as follows: Generally, 0~8nm, 0.01~6nm, 0.03~5nm, 0.05~4nm, 0.1~ The optical film is preferably purple. When an ultraviolet ray absorbing agent is contained, the Ro is, for example, 0 to 5 nm, preferably 0.01 to 3 nm, It is more preferably 0.03 to 1 nm, and most preferably 0.05 to 0.5 nm. If the phase difference Ro is too large, rainbow irregularities and light leakage will occur, reducing visibility through polarized sunglasses. There is a risk of it falling.

[0141] The thickness direction retardation Rth of the optical film is 589 nm at room temperature, 50 μm thick In this case, the thickness is 0 to 150 nm, and the preferred range is 1 to 100 nm in the following stepwise manner: m, 5-80nm, 10-70nm, 12-60nm, 15-50nm, and 20-3 When the optical film contains an ultraviolet absorber, the Rth is, for example, For example, 0 to 10 nm, preferably 0.01 to 5 nm, and more preferably 0.05 to 3 nm, The most preferable thickness direction retardation Rth is 0.1 to 1 nm. If the thickness direction retardation Rth is too large, rainbow unevenness and There is a risk that light leakage will occur and visibility through polarized sunglasses will be reduced.

[0142] The in-plane retardation Ro and thickness direction retardation Rth of the optical film are expressed by the following formulas, respectively: It can be calculated as follows.

[0143] Ro=(nx-ny)×d Rth=((nx+ny) / 2-nz)×d (wherein nx is the refractive index of the film in the slow axis direction, ny is the refractive index of the film in the fast axis direction, nz is the refractive index in the film thickness direction, and d is the film thickness).

[0144] In this specification and claims, the in-plane retardation Ro and the thickness direction retardation Rth can be measured by the method described in the Examples below.

[0145] The thickness (average thickness) of the optical film is not particularly limited, but is, for example, 20 to 300 μm. m, preferably 30 to 250 μm, further preferably 50 to 200 μm, and more preferably The thickness of the optical film ( The average thickness is 20 to 200 μm, preferably 30 to 150 μm, and more preferably 50 to 150 μm. The optical film may be a thin film having a thickness of 120 μm. It is particularly effective when it contains an infrared absorbing agent and is used as a polarizing plate protective film. If the optical film is too thin, its protective functions such as abrasion resistance may be reduced, while if it is too thick, If this occurs, there is a risk that bending resistance may decrease.

[0146] [Display cover sheet] The optical film is a cover sheet (or cover film) for a display, particularly The cover sheet may be a cover sheet for a foldable display, and the curable composition may contain an ultraviolet absorber. When the film contains It is preferably used as a cover sheet (polarizer protective film) for foldable displays. A sheet formed from a cured product of a curable composition containing an ultraviolet absorber is suitable for this application. The reasons for this are as follows:

[0147] Usually, the cover sheet for a foldable display is attached to the circular polarizer with an adhesive. However, the circular polarizer is made of thin polyvinyl chloride film formed by coating in order to withstand bending. The polyvinyl alcohol (PVA) polarizer and the thin acrylic protective film are bonded together with an adhesive. The acrylic protective film is used as a protective film for ordinary polarizing plates. The thickness of about 40 μm is not strong enough to withstand bending, so it is designed to be about half that thickness. The polarizing plate protective film has a function to protect the iodine in the polarizer (polarizing film) from ultraviolet rays. However, as the thickness becomes thinner, the acrylic resin of the UV absorber Its solubility in water is low, so it bleeds out easily, and it is difficult to add the amount required for UV absorption. For this reason, the amount of UV absorber that is insufficient is added to the adhesive, but the adhesive strength is Furthermore, the foldable cover sheet has the function of a protective film for the polarizing plate. By combining these features, the protective film can be eliminated, making the device thinner and more resistant to bending. Foldable displays are being considered, but they must be both thin and have good UV absorption properties. At present, there is no display that satisfies all the requirements for bonding with an A polarizer.

[0148] In contrast, in one preferred embodiment of the present invention, the curing of a curable composition containing an ultraviolet absorber is carried out. Because it is made of a compound, it can be made thin and has UV absorption ability, and it is easy to adhere to the PVA polarizer. Sexuality can also be improved.

[0149] The display cover sheet, which is one of the preferred embodiments of the present invention, is a polarizing plate protective film. It can be directly attached to a PVA polarizer because it functions as a protective film. The film usually needs to function as a support for the flexible PVA film, but In one preferred embodiment, the cover sheet is a soft film, and is formed by thermal shrinkage of PVA. However, it does not have the rigidity required for a support to withstand the stress of a foldable display. In the example, the image display device is an OLED, and its circular polarizer is a thin film PVA layer coated The film is composed of a laminate with an acrylic retardation film, and the shrinkage stress of the PVA The stiffness of the cover sheet is reduced by the rigid acrylic retardation film. By bonding it to the PVA layer with a strong adhesive, it can be integrated into a circular polarizer. Therefore, it can be adjusted so that the influence of PVA shrinkage stress does not occur.

[0150] The adhesive used to bond the PVA layer is an active energy ray curing adhesive. The adhesive may be an epoxy resin containing a photo-cationic polymerization initiator. Photo-cationic polymerizable adhesives such as adhesives made of a resin composition; (meth)acrylamide, (meth)acrylamide (meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate, etc. Examples of such adhesives include photo-radical polymerization adhesives such as adhesives made of (meth)acrylic resin compositions. These adhesives can be used alone or in combination. A combination of a polymerization adhesive and a photo-radical polymerization adhesive may also be used. The display cover sheet, which is one of the embodiments, is hydrophobic, so it has low moisture permeability and Therefore, the adhesive is a PVA type adhesive that requires drying of water. Aqueous adhesives are not preferred. Therefore, among the above adhesives, hydrophobic adhesives are preferred. In addition, the adhesive does not require a drying process or drying equipment, so it is an adhesive that does not contain organic solvents. Agents are preferred.

[0151] The display cover sheet used as a polarizing plate protective film is coated with an adhesive The adhesive is applied to the polarizing film, and a PVA layer is coated on the retardation film. After laminating the film with a nip roll, ultraviolet light is irradiated from the cured film side using an ultraviolet irradiation device. The adhesive can be cured by using a method such as the above.

[0152] To improve adhesion, polarizers and / or display cover sheets may be coated with Rona treatment, flame treatment, plasma treatment, UV treatment, primer coating treatment, saponification treatment, etc. The surface may be subjected to a surface modification treatment.

[0153] The laminated film obtained by bonding the display cover sheet and the polarizer is As a component that integrates a polarizer and a glass, it is used in foldable devices such as foldable smartphones. It can be installed in the terminal. [Example]

[0154] The present invention will be described in more detail below based on examples, but the present invention will not be limited to these examples. The raw materials and evaluation methods used are as follows: .

[0155] [Raw materials] BPEF-5EOGA: Synthesized by the method described in the examples of JP 2017-186513 A In the formula (1b), n1+n2=7. Epoxy Acrylate BPEF-9EOGA: Synthesized by the method described in the examples of JP 2017-186513 A In the formula (1b), n1+n2=11. Epoxy acrylate BNEF-13EOGA: A method described in the examples of JP 2017-186513 A The epoxy acrylate synthesized is represented by the formula (1a), 1a and Z 1b is a naphthalene ring, and n1+n2=15 BPEF-9EOA: 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluoro An average of 9 moles of ethylene oxide are added to 1 mole of olefin (BPEF). Diacrylate (Osaka Gas Chemicals Co., Ltd.) UV-3200B (ester type): manufactured by Nippon Synthetic Chemical Industry Co., Ltd., bifunctional urethane acrylate Related Epoxy Ester 3000A: Kyoeisha Chemical Co., Ltd., diglycidyl bisphenol A Ether acrylic acid adduct UV absorber A: Eversorb 109, Everlight Chemical made of viscous liquid UV absorber B: Eversorb BL1A, Everlight Chemical Company-made, viscous liquid Photopolymerization initiator A: BASF Japan Ltd., product name "Irgacure 184" Photopolymerization initiator B: BASF Japan Ltd., product name "Irgacure 819" Support film: Toray Industries, Inc., product name "PET Lumirror", film thickness 100 μm.

[0156] [Pencil hardness] In accordance with JIS K5600-5-4 (load 750g), a pencil hardness tester (Shinto Scientific Co., Ltd.) was used. The measurements were carried out using a "HEIDON-14" manufactured by ).

[0157] [Bending stability] Using a bending tester (YUASA SYSTEM Co., Ltd. "DMLHP-CS") The measurement was carried out as follows. That is, as shown in FIG. 2(a), first, the film 11 was A pair of plates 12, 13 of the tester 10 for holding the film are attached to the respective film-mounting surfaces 12a, 13a are fixed so as to be flush with each other, and the film is placed on the film placement surfaces 12a and 13a. The test piece 11 was placed on the pair of plates 12 and 13. The plates 12, 13 are rotated around the ends 12b, 13b of the base. By moving the film mounting surfaces 12a and 13a relative to each other, the film mounting surfaces 12a and 13a are moved by the spacers (not shown). ) and moved so that they faced each other across a distance R regulated by the In this closing operation, the plates 12 and 13 are closed as shown in FIG. As shown in FIG. 1, the film placement surfaces 12a and 13a are moved so that they are ultimately opposed and parallel to each other. The distance R between the film mounting surfaces 12a and 13a was adjusted to 4 mm.

[0158] By closing the pair of plates 12 and 13, the pair of plates 12 and 13 are in the state shown in FIG. 2(b). After leaving it at room temperature for 24 hours, the film 11 was removed from the tester 10 and the inside of the bent Place film 11 on a flat surface with the side facing up and leave it for 1 hour. The height at which the end of 11 was raised above the plane was measured.

[0159] [Bending durability] Using the bending tester 10, the test piece was closed by the same bending method as in the bending stability test. After the closing operation is performed, the pair of plates 12 and 13 are moved relative to each other in the opposite direction to the closing operation. As a result, as shown in FIG. 2(a), the film placement surfaces 12a and 13a are aligned in the same direction. The object was moved so that it became flat (hereinafter, this movement operation is called "opening operation"). The film was opened and closed 100,000 times or 1,000,000 times. By visually observing the surface of 1 for creases and breaks, it was confirmed that there were no creases in the film. The number of times the sample was bent was counted until the sample broke or the appearance became abnormal.

[0160] [Total light transmittance] In accordance with JIS K7361-1, a color difference turbidity meter (Nippon Denshoku COH-400) ") was used for measurement.

[0161] [Spectral transmittance] The spectral transmittance at 380 nm was measured using a spectrophotometer (Shimadzu Corporation's UV-360 0”) was used for the measurement.

[0162] [Yellowness (YI)] Color difference turbidity meter (Nippon Denshoku Co., Ltd. "COH-400") conforming to JIS K7373 was measured using

[0163] [Hayes] Color difference turbidity meter (Nippon Denshoku Co., Ltd. "COH-400") conforming to JIS K7136 was measured using

[0164] [Refractive Index] Multi-wavelength Abbe refractometer (ATAGO Co., Ltd. "DR-M4 (circulating constant temperature water bath 60-C3)") At a measurement temperature of 20°C, bromonaphthalene was used as the contact liquid, and the wavelength was measured at 589 nm (D line) The refractive index nD of the film was measured.

[0165] [Phase difference] The retardation measurement device (Otsuka Electronics Co., Ltd. "RETS-100") was used to measure the temperature. The Ro(550) and Rth(589) of the film were measured at 20°C. The values ​​are converted to film thickness of 50 μm. Ro(550) is the value obtained under the condition of a wavelength of 550 nm. Rth(589) is the in-plane retardation, and Rth(589) is the retardation in the thickness direction under the condition of a wavelength of 589 nm. do.

[0166] [Bleed Out] In the examples where an ultraviolet absorber was added, bleeding was observed on the surface of the cured film obtained. The presence or absence of out was visually observed.

[0167] Example 1 As shown in Table 1, 100 parts by mass of BPEF-9EOGA and 3 parts by mass of photopolymerization initiator A were used. The mixture was added and stirred at 70°C for 1 hour to obtain a curable composition. Then, it is applied to an ultraviolet irradiation device (Eye Graphics "ECS-151U") More UV radiation (500mJ / cm 2 ) to harden it and peel it off from the PET film. The resulting cured film was subjected to the pencil hardness test and the fold strength test. Bending stability, bending durability, total light transmittance, spectral transmittance, yellowness index, haze, refractive index, The retardation was measured, and the measurement results are shown in Table 2.

[0168] Examples 2 to 5 As shown in Table 1, the curable composition further contains an ultraviolet absorber A and a photopolymerization initiator. Cured films were prepared in the same manner as in Example 1, except that B was added in the amounts shown in the table. The thickness of the cured film of Example 3 was 90 μm.

[0169] The properties of the resulting cured film were measured in the same manner as in Example 1. The results are shown in Table 2. Shown below.

[0170] Examples 6 to 9 As shown in Table 1, the curable composition further contains an ultraviolet absorber B and a photopolymerization initiator. Cured films were prepared in the same manner as in Example 1, except that B was added in the amounts shown in the table.

[0171] The properties of the resulting cured film were measured in the same manner as in Example 1. The results are shown in Table 2. Shown below.

[0172] (Examples 10 to 11 and Comparative Examples 1 to 3) As shown in Table 1, instead of BPEF-9EOGA, BPEF-5EOGA and BNEF -13EOGA, BPEF-9EOA, UV-3200B (ester-based) or epoxy A cured film was prepared in the same manner as in Example 1, except that Ester 3000A was used. The thickness of the cured film was 90 μm in Comparative Example 1, 200 μm in Comparative Example 2, and The result was 120 μm.

[0173] The properties of the resulting cured film were measured in the same manner as in Example 1. The results are shown in Table 2. Shown below.

[0174] [Table 1]

[0175] [Table 2]

[0176] As is clear from the results in Table 2, in the examples, the surface hardness was high, and the bending stability and The optical properties are also excellent, as well as the durability. 0 to 11 indicate high pencil hardness, and in particular, when Example 1 is compared with Examples 10 to 11, The results showed that the pencil hardness decreased as the number of moles of ethylene oxide added increased. This was an unexpected result that could not be predicted from the results of the example in Reference 5. In this embodiment, the ratio of 1 to 3 parts by mass per 100 parts by mass of BPEF-9EOGA is preferred. In particular, 1 part by mass is particularly preferred because it improves the ultraviolet blocking ability and provides excellent properties. It's nice. [Industrial Applicability]

[0177] The optical film, which is one of the preferred embodiments of the present invention, is an image film that is repeatedly folded and used. It can be used as an optical film incorporated into the display unit of a display device. In particular, it has excellent surface hardness and foldability. It has bending resistance, so it can be used without hard coating or with ultra-thin hard coating. Since the surface hardness can be achieved simply by coating, it is suitable as a cover sheet for the display section. Furthermore, the optical film has excellent optical properties and low retardation, so that It is a cover sheet that also provides excellent visibility of the display, making it particularly suitable for foldable mobile information terminals. The portable information terminal can be suitably used. These include mobile PCs such as personal computers (PCs) and tablet PCs. It is suitable as a portable smartphone. [Explanation of symbols]

[0178] 1...Support film unwinding device 2...Support film 3...Curable composition 4...Coating head 5...Ultraviolet irradiation device 6...Support film winding device 7...Curing film 8...Cured film winding device

Claims

1. An optical film to be incorporated into a display unit of an image display device that is repeatedly folded when used, The average thickness is 20 to 120 μm, No creases or breaks occur even after repeated bending 100,000 times using a bending tester, and An optical film formed from a cured product of a curable composition which contains an epoxy (meth)acrylate represented by the following formula (1a) and which does not contain an ultraviolet absorber, or, if it contains an ultraviolet absorber, the proportion of the ultraviolet absorber is 3 parts by mass or less per 100 parts by mass of a total amount of (meth)acryloyl group-containing components: 【Chemical 1】 (In the formula, Ring Z １ａ and ring Z １ｂ are the same or different and represent a benzene ring or a naphthalene ring, R １ａ and R １ｂ are the same or different and each represent a C 1-4 alkyl group or a C 6-10 aryl group; m1 and m2 are the same or different and each represent an integer of 0 or more; A １ａ and A １ｂ are the same or different and represent a linear or branched alkylene group; n1 and n2 are the same or different and represent an integer of 1 or more; n1+n2 represents an integer of 2 to 30; R ２ａ and R ２ｂ are the same or different and represent a hydrogen atom or a methyl group, R 4 represents a substituent, and k represents an integer of 0 to 8.

2. 2. The optical film according to claim 1, wherein the epoxy (meth)acrylate is an epoxy (meth)acrylate represented by the following formula (1b): 【Chemistry 2】 (wherein n1+n2 represents an integer of 3 to 20)

3. The optical film according to claim 1 or 2, wherein the curable composition contains the ultraviolet absorber.

4. The optical film according to any one of claims 1 to 3, wherein the cured product is a photocured product.

5. 5. The optical film according to claim 1, wherein the in-plane retardation Ro(550) is 50 nm or less and the thickness direction retardation Rth(589) is 100 nm or less.

6. 6. The optical film according to claim 1, wherein the total light transmittance is 85% or more and the spectral transmittance at 380 nm is 8% or less.

7. 7. The optical film according to claim 1, which is a cover sheet for a display.

8. The optical film according to any one of claims 1 to 7, which is a polarizing plate protective film.

9. 9. The optical film according to claim 1, wherein the film does not develop creases or breaks even when repeatedly bent 1 million times using a bending tester.

10. A polarizing plate comprising the optical film according to any one of claims 1 to 9 and a polyvinyl alcohol polarizer bonded together with an adhesive.

11. The polarizing plate of claim 10, wherein the optical film contains the ultraviolet absorber and the adhesive does not contain the ultraviolet absorber.

12. An image display device comprising the optical film according to any one of claims 1 to 9.

13. 13. The image display device according to claim 12, comprising an organic electroluminescence display.

14. 14. The image display device according to claim 12, which is a foldable portable information terminal.

15. A method for using an image display device that is repeatedly folded and used, by placing the optical film according to any one of claims 1 to 9 on the surface of a display unit thereof, and using the optical film as a cover sheet.

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