TW202237686A - Optical membrane and its use - Google Patents

Abstract

An optical film is formed from a cured product of a curable composition containing an epoxy (meth) acrylate represented by the following formula (1).

[In the formula, X represents a particular linking group, rings Z^1a and Z^1b represent arene rings that are identical or different from each other, R^1a and R^1b represent substituents that are identical or different from each other, m1 and m2 represent integers greater than or equal to 0 that are identical or different from each other, A^1a and A^1b represent linear or branched alkylene groups that are identical or different from each other, n1 and n2 represent integers greater than or equal to 1 that are identical or different from each other, and R^2a and R^2b represent hydrogen atoms or methyl groups that are identical or different from each other].

The optical film is incorporated into a display unit of an image display device that is repeatedly bent and used. The optical film can have both bending resistance and surface hardness.

Description

Optical film and its application

The present invention relates to an optical film that is excellent in bending resistance and excellent in surface hardness and can be used as a cover sheet for a display, and its use.

In recent years, the high functionality of smartphones has progressed remarkably, and foldable smartphones have been proposed as one of them. A foldable smart phone can fold or unfold a single screen, and use a single terminal to become both a smart phone and a tablet computer. It has the advantage of being able to combine the portability of a smart phone with the large screen of a tablet computer. However, there are still many technical issues until practical use.

The display of a foldable smartphone is not a liquid crystal display (LCD) using a glass substrate, but an organic electroluminescent (EL) display (OLED) that can be fully plasticized in order to be foldable. Furthermore, for the transparent electrodes of OLEDs, the use of metal meshes such as copper meshes, rather than indium tin oxide (ITO), which is weak and easy to break, is being reviewed. Further, in forming the substrate of low-temperature polysilicon TFT (Thin Film Transistor), a polyimide substrate is used instead of a glass substrate, and a thin film sealing layer and a barrier film are used instead of glass sealing for OLED sealing .

Film materials such as touch sensors, circular polarizing plates, λ/4 retardation plates for reading sunglasses, and cover sheets are laminated on top of OLEDs, and OCA (Optical Clear Adhesive) or An adhesive layer such as PSA (Pressure Sensitive Adhesive). Furthermore, A surface treatment layer such as a hard coat layer is formed on the cover sheet. Regarding the touch sensor, in the out-cell type, a metal mesh electrode is formed on a polyethylene terephthalate (PET) film, and in the on-cell type, it is Metal mesh electrodes are formed on the thin film sealing layer of the OLED. In order to make a foldable smartphone practical, it is necessary to further combine all the films and thin film layers with their original functions, and to further combine the bending resistance (restraining damage or crease even after repeated bending) The resulting bending durability, even if it is bent for a long time, still suppresses the bending inertia (deformation) of the bending stability).

Among them, the cover sheet is used on the outermost surface, so it requires strict performance on surface hardness or wear resistance. However, due to the compromise relationship between surface hardness and bending resistance, it is not easy to be compatible with the two. a characteristic. Bending resistance is related to the elastic coefficient and film thickness of the film. The lower the elastic coefficient, the higher the bending resistance (it is difficult to cause damage and deformation due to bending), and the thinner the film thickness, the higher the bending resistance. On the other hand, the lower the modulus of elasticity or the thinner the film thickness, the lower the surface hardness tends to be. Various transparent polyimides with excellent bending resistance have been proposed as film materials for the cover sheet (please refer to Patent Documents 1 to 4).

On the other hand, materials capable of both high hardness and flexibility have been proposed, such as epoxy acrylate hardened products having a 9,9-bis(aryl) fluorine structure and an oxyalkylene chain (please refer to Patent Document 5).

[Prior Art Literature]

[Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2018-28073

[Patent Document 2] Japanese Patent Laid-Open No. 2019-052287

[Patent Document 3] WO2017/191830

[Patent Document 4] Japanese Patent Laid-Open No. 2019-051718

[Patent Document 5] Japanese Patent Laid-Open No. 2017-186513

However, none of the transparent polyimides in Patent Documents 1 to 4 have sufficient surface hardness, and must be hard-coated for use as a cover sheet. In addition, in order to increase the hardness, the thickness of the hard coat layer is increased, and there is a problem that the curl due to curing shrinkage becomes larger. Furthermore, the bending resistance is not only the durability for repeated bending, but also requires no bending inertia when kept in a bent state for a long time. Although transparent polyimides have high durability against repeated bending, it was found that transparent polyimides with hard coatings have bending inertia, and thus must be improved.

On the other hand, in Patent Document 5, the use of the cured product described in this document is not conceived as a cover sheet for a foldable terminal at all, and the physical property values required for such an application are also completely absent. any hint.

Therefore, the object of the present invention is to provide an optical film capable of both bending resistance and surface hardness and its application.

The inventors of this case have actively studied to achieve the above-mentioned problems, and found that a film formed of a cured product of epoxy acrylate having a specific aromatic hydrocarbon skeleton has excellent bending resistance and surface hardness, and thus completed the present invention invention. In particular, it was found that when a structure having a rigid 9,9-bis(aryl) fluorene skeleton and a soft oxyethylene chain of an appropriate length is selected as the aforementioned aromatic hydrocarbon skeleton, high flexibility and surface hardness can be achieved, and moreover Furthermore, in addition to high transparency, the film system formed by the cured product is relatively The position difference is also small, even if it is used as a cover sheet, there is no iridescence or light leakage, and the visibility through polarized sunglasses is also excellent.

One of the suitable forms of the present invention is an optical film which is incorporated into the display part of an image display device which is repeatedly bent and used, and is composed of a (meth)acrylic ring represented by the following formula (1) The hardened product of the curable composition of oxyester.

[where,

X represents a linking group selected from the group of the following formula (2),

(where,

R ^3a and R ^3b are the same or different from each other and represent hydrogen atom, fluorine atom, chlorine atom, bromine atom, iodine atom, C _1-9 alkyl, C _1-5 alkoxy, C _4-12 cycloalkyl , C _6-12 aryl, C _2-5 alkenyl or C _7-17 aralkyl, R ^3a and R ^3b can also be bonded to form a carbocyclic or heterocyclic ring,

p represents an integer greater than 1);

Ring Z ^1a and ring Z ^1b are the same or different from each other and represent an aromatic hydrocarbon (arene) ring,

R ^1a and R ^1b are the same or different from each other and represent a substituent, m1 and m2 are the same or different from each other and represent an integer of 0 or more,

A ^1a and A ^1b are the same or different from each other and represent a linear or branched chain alkylene group, n1 and n2 are the same or different from each other and represent an integer of 1 or more,

R ^2a and R ^2b are the same or different from each other and represent a hydrogen atom or a methyl group].

One of the preferred aspects of the present invention is that the epoxy (meth)acrylate is an epoxy (meth)acrylate represented by the following formula (1a).

(where,

R represents a substituent, k represents an integer from 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 are the same as above).

One of the preferred aspects of the present invention is that in the aforementioned formula (1), ring Z ^1a and ring Z ^1b are the same or different from each other and represent a benzene ring or a naphthalene ring, R ^1a and R ^1b are the same or different from each other and represents a C _1-4 alkyl group or a C _6-10 aryl group, and n1+n2 represents an integer from 2 to 30.

One of the preferred aspects of the present invention is that the epoxy (meth)acrylate is an epoxy (meth)acrylate represented by the following formula (1b).

(In the formula, n1+n2 represents an integer of 3 to 20).

One of the preferred aspects of the present invention is that the ratio of the epoxy (meth)acrylate represented by the aforementioned formula (1a) is 70% in the epoxy (meth)acrylate represented by the aforementioned formula (1). to 100 mol%.

One of the preferred aspects of the present invention is that the aforementioned curable composition further contains an ultraviolet absorber.

One of the preferred aspects of the present invention is that the aforementioned cured product is a light cured product.

One of the preferred aspects of the present invention is that the optical film has an in-plane retardation Ro(550) of 50 nm or less, and a thickness direction retardation Rth(589) of 100 nm or less.

One of the preferred aspects of the present invention is that the total light transmittance of the aforementioned optical film is above 85%, and the spectral light transmittance at 380nm is below 8%.

One of the preferred aspects of the present invention is that the aforementioned optical film is a cover sheet for a display.

One of the preferred aspects of the present invention is that the aforementioned optical film is a polarizing plate protective film.

One of the preferred aspects of the present invention is that the average thickness of the aforementioned optical film is 20 to 200 μm.

One of the preferred aspects of the present invention is a polarizing plate, which is formed by laminating the aforementioned optical film and polyvinyl alcohol polarizer with an adhesive.

One of the preferred aspects of the present invention is that the optical film contains a UV absorber, and the adhesive does not contain a UV absorber.

One of the preferred aspects of the present invention is an image display device including the aforementioned optical film.

One of the preferred aspects of the present invention is that the aforementioned image display device includes an organic electroluminescent (EL) display.

One of the preferred aspects of the present invention is that the aforementioned image display device is a foldable portable information terminal.

One of the preferred aspects of the present invention is a method of placing the aforementioned optical film on the surface of a display portion of an image display device that is repeatedly bent and used, and using the aforementioned optical film as a cover sheet.

In addition, in this specification and claims, the number of carbon atoms of a substituent may be represented by C ₁ , C ₆ , C ₁₀ or the like. For example, "C ₁ alkyl" means an alkyl group with 1 carbon number, and "C _6-10 aryl" means an aryl group with 6 to 10 carbon atoms.

In the present invention, since the optical film is formed of a cured product of epoxy acrylate having a specific aromatic hydrocarbon skeleton, it is excellent in bending resistance and also excellent in surface hardness. In particular, by selecting a structure having a rigid 9,9-bis(aryl) fluorene skeleton and a soft oxyalkylene chain of an appropriate length as the aforementioned aromatic hydrocarbon skeleton, it is possible to have both high flexibility and surface hardness , and has high transparency and small retardation, even if it is used as a cover sheet, there is no iridescence or light leakage, and the visibility through polarized sunglasses is also excellent. Especially in the case where the optical film contains a UV absorber, it is effective as a protective film for polarizing plates, and can be used even if it is thin. It can suppress the bleed out of the ultraviolet absorber, can achieve both thinness and ultraviolet absorption ability, and can also improve the adhesiveness with the polarizer.

1: Support film roll-out device

2: Support film

3: hardening composition

4: coating head

5: UV irradiation device

6: Support film take-up device

7: hardened film

8: Cured film winding device

Fig. 1 is a schematic diagram of the manufacturing steps of an optical film according to one of the suitable aspects of the present invention.

FIG. 2 is a schematic diagram for illustrating a bending method of an optical film in a bending stability test.

Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

[Epoxy(meth)acrylate]

One of the preferred aspects of the present invention is that the curable composition contains epoxy (meth)acrylate represented by the aforementioned formula (1).

In the aforementioned formula (1), p in -(CH2) _p - of the linking group of X needs to be an integer of 1 or more, preferably 1 to 10, more preferably 1 to 6, more preferably 2 to 4 .

Among the linking groups X, it is preferable that R ^3a and R ^3b form a linking group of an aliphatic hydrocarbon ring such as a cyclohexane ring or a cyclodecane ring or a carbocyclic ring such as an aromatic hydrocarbon ring. Preferably, R ^3a and R ^3b form a linking group of an aromatic carbocycle, most preferably, R ^3a and R ^3b form a linking group of an oxene ring.

In the aforementioned formula (1), the aromatic hydrocarbon rings (or aromatic hydrocarbon rings) represented by ring Z ^1a and ring Z ^1b can be roughly divided into monocyclic aromatic hydrocarbon rings (monocyclic aromatic hydrocarbon rings) such as benzene rings, polycyclic aromatic hydrocarbon rings, and polycyclic aromatic hydrocarbon rings. Aromatic hydrocarbon ring (polycyclic aromatic hydrocarbon ring). Examples of the polycyclic aromatic hydrocarbon ring include condensed polycyclic aromatic hydrocarbon rings (condensed polycyclic aromatic hydrocarbon rings), ring-assembled aromatic hydrocarbon rings (ring-assembled aromatic hydrocarbon rings), and the like.

Examples of condensed polycyclic aromatic hydrocarbon rings include condensed bicyclic aromatic hydrocarbon rings, condensed tricyclic aromatic hydrocarbon rings, and condensed bicyclic to tetracyclic aromatic hydrocarbon rings. The condensed bicyclic aromatic hydrocarbon rings include, for example, condensed bicyclic C _10-16 aromatic hydrocarbon rings such as naphthalene rings. Examples of condensed tricyclic aromatic hydrocarbon rings include onion rings, phenanthrene rings, and the like.

The ring-assembled aromatic hydrocarbon ring includes, for example, a bis-aromatic hydrocarbon ring such as a double C _6-12 aromatic hydrocarbon ring, a tri-aromatic hydrocarbon ring such as a tri-C _6-12 aromatic hydrocarbon ring, and the like. The double C _6-12 aromatic hydrocarbon rings can be, for example, biphenyl rings; binaphthyl rings; phenylnaphthalene rings such as 1-phenylnaphthalene rings and 2-phenylnaphthalene rings, etc. The three C _6-12 aromatic hydrocarbon rings can be, for example, terphenylene rings and the like.

Among these aromatic hydrocarbon rings, C _6-12 aromatic hydrocarbon rings such as benzene ring, naphthalene ring, and biphenyl ring are preferred. From the viewpoint of having both bending resistance and surface hardness, C _6-10 aromatic hydrocarbon rings, the best being benzene ring. Ring Z ^1a and ring Z ^1b may also be different rings, but are usually the same ring.

In the aforementioned formula (1), the substituents represented by R ^1a and R ^1b are not particularly limited as long as they are non-reactive substituents for epoxy groups, for example: halogen atoms, hydrocarbon groups, alkoxy groups, cycloalkane Oxy, aryloxy, aralkyloxy, alkylthio, cycloalkylthio, arylthio, aralkylthio, acyl, nitro, cyano, etc.

The aforementioned halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. The hydrocarbon group includes, for example, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and the like. Alkyl can be exemplified: methyl, ethyl, n-propyl, isopropyl, n-butyl, second butyl, isobutyl, tertiary butyl and other linear or branched C _1-10 alkane The group is preferably a linear or branched C _1-6 alkyl group, and more preferably a linear or branched C _1-4 alkyl group. Cycloalkyl groups include, for example, C _5-10 cycloalkyl groups such as cyclopentyl and cyclohexyl. Examples of the aryl group include _C6-12 aryl groups such as phenyl, alkylphenyl, biphenyl, and naphthyl. Examples of the alkylphenyl group include methylphenyl (ie, tolyl), dimethylphenyl (ie, xylyl), and the like. Aralkyl groups include, for example, C _6-10 aryl-C _1-4 alkyl groups such as benzyl and phenethyl.

The alkoxy group can be, for example: methoxy, ethoxy, propoxy, n-butoxy, isobutoxy, tert-butoxy and other linear or branched C _1-10 alkoxy groups Wait. Cycloalkoxy groups include, for example, C _5-10 cycloalkoxy groups such as cyclohexyloxy and the like. The aryloxy group is, for example, C _6-10 aryloxy group such as phenoxy group and the like. Examples of the aralkoxy group include C _6-10 aryl-C _1-4 alkoxy such as benzyloxy. Examples of the alkylthio group include C _1-10 alkylthio groups such as methylthio, ethylthio, propylthio, n-butylthio, t-butylthio, and the like. Cycloalkylthio can be, for example, C _5-10 cycloalkylthio such as cyclohexylthio. Examples of the arylthio group include: C _6-10 arylthio groups such as thiophenoxy and the like. The aralkylthio group can be, for example, C _6-10 aryl-C _1-4 alkylthio such as benzylthio. Examples of the acyl group include C _1-6 acyl groups such as acetyl groups and the like.

Among these substituents, representative examples include halogen atoms; hydrocarbon groups such as alkyl groups, cycloalkyl groups, and aralkyl groups; alkoxy groups; acyl groups; nitro groups; cyano groups; Preferred R ^1a and R ^1b can be, for example: alkyl, cycloalkyl, aryl, alkoxy, and the alkyl can be, for example, linear or branched C _1-6 alkyl such as methyl, etc. Examples of cycloalkyl groups include: cyclohexyl and other C _5-8 cycloalkyl groups, etc., examples of aryl groups include: C _6-14 aryl groups such as phenyl, etc., examples of alkoxy groups include: methoxy, etc. Straight chain or branched C _1-4 alkoxy, etc. In particular, the alkyl group can be, for example, a linear or branched C _1-4 alkyl group such as a methyl group. Substituent R ^1a and substituent R ^1b may also be different substituents, but are usually the same substituent.

The substitution numbers m1 and m2 of R ^1a and R ^1b need only be an integer of 0 or more, which can be appropriately selected according to the type of ring Z ^1a and ring Z ^1b , and can be integers such as 0 to 8, respectively. The preferred substitution number m1 And m2 is an integer of 0 to 4, an integer of 0 to 3, an integer of 0 to 2, 0 or 1, preferably 0 in stages as follows. The substitution numbers m1 and m2 may also be different substitution numbers, but are usually the same substitution number. Furthermore, when the substitution numbers m1 and m2 are 2 or more, the types of R ^1a or R ^1b of 2 or more may be the same or different. In particular, when m1 and m2 are 1, ring Z ^1a and ring Z ^1b are preferably benzene rings, naphthalene rings or biphenyl rings, and R ^1a and R ^1b are methyl groups. Furthermore, the substitution position of R ^1a and R ^1b is not particularly limited, as long as the substitution is at a position other than the binding position of ring Z ^1a and ring Z ^1b with the ether bond (-O-) and the linking group X.

In the aforementioned formula (1), the alkylene groups A ^1a and A ^1b can be, for example: ethylidene, propylidene (that is, 1,2-propanediyl), trimethylene, 1,2-butanediyl, Linear or branched C _2-6 alkylene groups such as tetramethylene. Among these, a linear or branched C _2-4 alkylene group is preferred, a linear or branched C _2-3 alkylene group is more preferred, and an ethylene group is most preferred.

The repeating numbers (addition mole numbers) n1 and n2 of the oxyalkylene group (OA ^1a ) and the oxyalkylene group (OA ^1b ) need only be an integer of 1 or more, for example, 1 to 20. n1 and n2 are preferably integers of 1 to 15, 1 to 10, 2 to 9, 2 to 8, and 2 to 7 in stages as follows, and are most preferably integers of 3 to 6. Furthermore, n1 and n2 can be the same or different. Furthermore, when n1 or n2 is 2 or more, the 2 or more oxyalkylene groups (OA ^1a ) or oxyalkylene groups (OA ^1b ) may be the same or different, respectively. Furthermore, the oxyalkylene group (OA ^1a ) and the oxyalkylene group (OA ^1b ) may be the same as or different from each other.

In addition, in this description and the scope of the patent application, the so-called "repeated number (addition mole number)" can be the average value (arithmetic mean value, summed average value) or the average addition mole number, and the preferred form is the same as The range of preferred integers is the same.

When ring Z ^1a and ring Z ^1b are monocyclic aromatic hydrocarbon rings such as benzene rings or aromatic hydrocarbon rings such as biphenyl rings, n1+n2 can be selected from an integer range of, for example, 2 to 30, and the preferred range It is an integer of 3 to 25, 4 to 20, 5 to 18, 6 to 16, 7 to 15, 8 to 14, and 9 to 13 in stages, preferably 10 to 12. These ranges of n1+n2 may also be ranges when ring Z ^1a and ring Z ^1b are benzene rings.

On the other hand, when ring ^Z1a and ring ^Z1b are condensed polycyclic aromatic hydrocarbon rings such as naphthalene rings, n1+n2 may be 3 or more from the viewpoint that the hardened product tends to become rigid and the flexibility tends to decrease. The integer is preferably an integer of 4 or more, more preferably an integer of 5 or more, most preferably an integer of 6 or more. When ring Z ^1a and ring Z ^1b are condensed polycyclic aromatic hydrocarbon rings such as naphthalene rings, n1+n2 can be selected from an integer range of about 3 to 30, and the preferred range is as follows: 4 to 25, 5 An integer of up to 20, 6 to 18, 7 to 15, 8 to 13, preferably an integer of 10 to 15.

As mentioned above, n1+n2 can be an integer, but it can also be the average value (or average addition mole number) of the molecular aggregate of the compound represented by the aforementioned formula (1). n1+n2 can be selected from, for example, the range of about 2 to 30, regardless of the type of ring ^Z1a and ring ^Z1b , can be selected from the range of about 2.5 to 25, and the preferred range is as follows in stages from 3 to 20, 5 to 18, 6 to 17, 7 to 16, 7.5 to 15, 8 to 14, 9 to 13, 9.5 to 12.5, 10 to 12, most preferably 10.5 to 11.5.

When the value of n1+n2 is too small, the crosslink density of the hardened product tends to increase, and furthermore, the flexibility due to the oxyalkylene group becomes difficult to express. Therefore, it is difficult to balance the surface hardness and bending resistance in a good balance. Concern about sex. Conversely, when the value of n1+n2 is too large, the crosslinking density of the hardened product is significantly reduced, and the surface hardness and bending resistance cannot be well balanced, and each unit amount (unit mass) contains ring Z ^1a and ring Z ^1b The content of the skeleton (the number of moles of the skeleton formed by bonding the aromatic hydrocarbon ring via the linking group X) is also reduced. Therefore, the excellent characteristics such as low birefringence and high heat resistance derived from the aforementioned skeleton may be reduced.

In particular, as will be described later, when the above-mentioned skeleton is a 9,9-bis(aryl)fennel skeleton bonded by using a fluorene ring as a linking group X, not only a high degree of low birefringence and heat resistance can be obtained, but even A large value of n1+n2 can also provide a well-balanced hardened product with high hardness and flexibility (bending resistance). The n1+n2 of the epoxy (meth)acrylate whose skeleton is 9,9-bis(aryl)oxene skeleton can be selected from an integer ranging from 3 to 20, and the preferred range is as follows: 4 to 20 An integer of 18, 4 to 17, 5 to 16, 7 to 15, 8 to 14, 9 to 13, preferably an integer of 10 to 12. In particular, as long as it is an integer of 8 to 14, preferably 9 to 13, and even more preferably 10 to 12, high hardness is exhibited even though the side chain is relatively long.

The substitution position of the group containing an oxyalkylene group is not particularly limited, and it can be substituted at an appropriate position of ring Z ^1a and ring Z ^1b . For example, when ring Z ^1a and ring Z ^1b are benzene rings, the substitution position can be any of the 2-6 positions, such as 2-position, 3-position, 4-position, etc., preferably 3-position and 4-position, The best department is 4 places. Furthermore, when the ring Z ^1a and the ring Z ^1b are naphthalene rings, the substitution position is often at the 5-8 position of the naphthyl group, for example, the 1-position or 2-position of the naphthalene ring is substituted with respect to the linking group X (with 1 -Naphthyl or 2-naphthyl substitution), relative to this substitution position, the relationship of 1,5, 16, 2,6 is better, and the relationship of 2,6 is the best. Furthermore, when ring Z ^1a and ring Z ^1b are biphenyl rings, they may be substituted on the aromatic hydrocarbon ring bonded to the linking group X or the aromatic hydrocarbon ring adjacent to the aromatic hydrocarbon ring. For example, the 3rd or 4th position of the biphenyl ring can be bonded to the linking group X. When the 3rd position of the biphenyl ring is bonded to the linking group X, the substitution position of the group containing the oxyalkylene group can be 2, 4 to 6, and any one of 2' to 6', usually 4, 5, 6, 3', 4', preferably 4, 6, 4', most Preferably 6 digits.

The groups R ^2a and R ^2b may be either a hydrogen atom or a methyl group, but are preferably a hydrogen atom from the viewpoint of reactivity. The groups R ^2a and R ^2b can also be different from each other, but are usually the same.

From the standpoint of having both surface hardness and bending resistance, no phase difference, and excellent visibility of image display devices, the epoxy (meth)acrylate represented by the aforementioned formula (1) is preferably The epoxy (meth)acrylate represented by the aforementioned formula (1a) is preferably the epoxy (meth)acrylate represented by the aforementioned formula (1b).

In the aforementioned 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 are to include preferred aspects All are the same as the aforementioned formula (1).

In addition, the substitution positions of ring Z ^1a and ring Z ^1b bonded to the 9-position of ^{oxene are} as described above. For example, 2-position, 3-position, 4-position, etc., preferably 3-position, 4-position, most preferably 4-position as in the aforementioned formula (1b).

In the aforementioned ^formula (1a), the substituent represented by R is not particularly limited as long as it is a non-reactive substituent to the epoxy group, and examples thereof include hydrocarbon groups such as alkyl groups and aryl groups, cyano groups, and halogen atoms. Examples of the alkyl group include linear or branched C _1-6 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl. The aryl group can be, for example, a C _6-10 aryl group such as a phenyl group and the like. Examples of the halogen atom include fluorine atom, chlorine atom, bromine atom and the like. These substituents can be used individually or in combination of 2 or more types.

Among these substituents, alkyl groups, cyano groups, and halogen atoms are preferred, and linear or branched C _1-4 alkyl groups are particularly preferred. Furthermore, among linear or branched C _1-4 alkyl groups, a linear or branched C _1-3 alkyl group is preferred, and a C _1-2 alkyl group such as methyl is particularly preferred.

^The substitution number k of R4 is an integer of 0 to 8, and the preferred range is an integer of 0 to 6, an integer of 0 to 4, and an integer of 0 to 2 step by step, with 0 being the best. In addition, when k is 2 or more, the types of each R ⁵ may be the same as or different from each other. Furthermore, when k is 2 or more, the types of 2 or more R ⁴ substituted on the same or different benzene rings may be the same or different from each other. Furthermore, the substitution position of R4 is not particularly limited, for example, it can be any one of the ² -position 7 of the oxene ring, usually any one of the 2-position, 3-position and 7-position.

Among the epoxy (meth)acrylates represented by the aforementioned formula (1a), representative compounds can be exemplified: in the aforementioned formula (1a), ring Z ^1a and ring Z ^1b are benzene rings, n1=n2 =1 compound, that is, 9,9-bis[(3-(meth)acryloyloxy-2-hydroxypropoxy) alkoxyphenyl] stilbenes; in the aforementioned formula (1a), the ring Z ^1a and ring Z ^1b are benzene rings or naphthalene rings, n1 and n2 are 2 to 10 compounds, that is, 9,9-bis[(3-(meth)acryloxy-2-hydroxypropoxy ) polyalkoxyphenyl] stilbenes; 9,9-bis[(3-(meth)acryloxy-2-hydroxypropoxy) polyalkoxynaphthalene] stilbenes, etc.

9,9-bis[(3-(meth)acryloyloxy-2-hydroxypropoxy)alkoxyphenyl]oxenes include ring Z ^1a and ring Z ^1b in the aforementioned formula (1a). It is a substituted or unsubstituted benzene ring, k=0, A ^1a and A ^1b are C _2-4 alkylene, n1=n2=1 compounds, for example: (1a-1)9,9-bis[4- (2-(3-(meth)acryloyloxy-2-hydroxypropoxy)ethoxy)phenyl]fen, 9,9-bis[4-(2-(3-(meth)propene 9,9-bis[(3-(meth)acryloxy-2-hydroxypropoxy)C _2-4 alkane (1a-2)9,9-bis[4-(2-(3-(meth)acryloyloxy-2-hydroxypropoxy)ethoxy)-3-methyl phenyl] fennel, 9,9-bis[4-(2-(3-(methyl)acryloyloxy-2-hydroxypropoxy)propoxy)-3-methylphenyl] terme, 9,9-bis[4-(2-(3-(meth)acryloxy-2-hydroxypropoxy)ethoxy)-3-isopropylphenyl] [4-(2-(3-(Meth)acryloxy-2-hydroxypropoxy)ethoxy)-3-isobutylphenyl] terme, 9,9-bis[4-(2 -(3-(Meth)acryloyloxy-2-hydroxypropoxy)ethoxy)-3-tert-butylphenyl] fluorine, 9,9-bis[4-(2-(3- (Meth)acryloxy-2-hydroxypropoxy)ethoxy)-3,5-dimethylphenyl] fluorine, 9,9-bis[4-(2-(3-(methyl) ) acryloxy-2-hydroxypropoxy)ethoxy)-3-tert-butyl-6-methylphenyl] fluorine, 9,9-bis[4-(2-(3-(methyl Base) acryloxy-2-hydroxypropoxy)ethoxy)-2,5-dimethylphenyl] 9,9-bis[(3-(meth)acryloxy-2 -Hydroxypropoxy)C _2-4 alkoxy-mono- or di-C _1-4 alkylphenyl] fennel; (1a-3)9,9-bis[4-(2-(3-(methyl ) acryloxy-2-hydroxypropoxy)ethoxy)-3-cyclohexylphenyl] terpene, 9,9-bis[4-(2-(3-(methyl)acryloxy- 2-Hydroxypropoxy)propoxy)-3-cyclohexylphenyl]Oxyl, etc. 9,9-bis[(3-(methyl)acryloxy-2-hydroxypropoxy)C _2-4 Alkoxy-C _5-10 cycloalkylphenyl] terpene; (1a-4) 9,9-bis[4-(2-(3-(meth)acryloxy-2-hydroxypropoxy )Ethoxy)-3-phenylphenyl] terpene, 9,9-bis[4-(2-(3-(meth)acryloxy-2-hydroxypropoxy)propoxy)- 3-phenylphenyl] 9,9-bis[(3-(meth)acryloxy-2-hydroxypropoxy)C _2-4 alkoxy-C _6-10 arylphenyl ] Fu et al.

9,9-bis[(3-(meth)acryloxy-2-hydroxypropoxy) polyalkoxyphenyl] fluorines can include ring Z ^1a and ring Z in the aforementioned formula (1a). ^1b is a substituted or unsubstituted benzene ring, k=0, A ^1a and A ^1b are C _2-4 alkylene, n1 and n2 are respectively 2 to 10 compounds, that is, corresponding to the aforementioned (1a-1) to Compounds of (1a-4) where n1 and n2 are 2 to 10, for example: (1a-5)9,9-bis[4-(2-(2-(3-(meth)acryloxy) Base-2-hydroxypropoxy)ethoxy)ethoxy)phenyl]fenene, 9,9-bis[4-(2-(2-(3-(meth)acryloyloxy-2- Hydroxypropoxy)propoxy)propoxy)phenyl]fenene, 9,9-bis[4-(2-(2-(2-(3-(meth)acryloyloxy-2-hydroxy Propoxy) ethoxy) ethoxy) ethoxy) phenyl] fen, etc. _2-4 alkoxyphenyl] fennel; (1a-6) 9,9-bis[4-(2-(2-(3-(meth)acryloyloxy-2-hydroxypropoxy)ethyl Oxy)ethoxy)-3-methylphenyl]terpine, 9,9-bis[4-(2-(2-(3-(meth)acryloxy-2-hydroxypropoxy) Propoxy)propoxy)-3-methylphenyl]terpine, 9,9-bis[4-(2-(2-(2-(3-(meth)acryloxy-2-hydroxy Propoxy)ethoxy)ethoxy)ethoxy)-3-isopropylphenyl] terpene, 9,9-bis[4-(2-(2-(3-(meth)acryl) Oxy-2-hydroxypropoxy) ethoxy) ethoxy) -3,5-dimethylphenyl] fluorine, etc. 9,9-bis[(3-(meth)acryloxy-2 -Hydroxypropoxy) two to decaC _2-4 alkoxy-mono- or two C _1-4 alkylphenyl] fluorene; (1a-7) 9,9-bis[4-(2-(2- (3-(Meth)acryloyloxy-2-hydroxypropoxy)ethoxy)ethoxy)-3-cyclohexylphenyl]oxene, 9,9-bis[4-(2-(2 -(3-(Meth)acryloyloxy-2-hydroxypropoxy)propoxy)propoxy)-3-cyclohexylphenyl]oxene, 9,9-bis[4-(2-( 9,9- Bis[(3-(meth)acryloxy-2-hydroxypropoxy)di to decaC _2-4 alkoxy-C _5-10 cycloalkylphenyl] fluorine; (1a-8)9 , 9-bis[4-(2-(2-(3-(meth)acryloxy-2-hydroxypropoxy)ethoxy)ethoxy)-3-phenylphenyl] terpene, 9,9-bis[4-(2-(2-(3-(methyl)acryloxy-2-hydroxypropoxy)propoxy)propoxy)-3-phenylphenyl]terpinene , 9,9-Double[4-(2-(2-(2-( 3-(Meth)acryloxy-2-hydroxypropoxy)ethoxy)ethoxy)ethoxy)-3-phenylphenyl]Oxyl, etc. 9,9-bis[(3-( Meth) acryloxy-2-hydroxypropoxy) two to ten C _2-4 alkoxy-C _6-10 arylphenyl] fluorine and the like.

9,9-bis[(3-(meth)acryloyloxy-2-hydroxypropoxy)polyalkoxynaphthalene] fluorines include ring Z ^1a and ring Z ^1b in the aforementioned formula (1a). It is a substituted or unsubstituted naphthalene ring, k=0, A ^1a and A ^1b are C _2-4 alkylene, n1 and n2 are 2 to 10 compounds, for example: (1a-9)9,9-bis [6-(2-(2-(3-(Meth)acryloyloxy-2-hydroxypropoxy)ethoxy)ethoxy)-2-naphthalene] fluorine, 9,9-bis[6 -(2-(2-(3-(Meth)acryloxy-2-hydroxypropoxy)propoxy)propoxy)-2-naphthalene]Oxene, 9,9-bis[6-( 2-(2-(2-(3-(Meth)acryloyloxy-2-hydroxypropoxy)ethoxy)ethoxy)ethoxy)-2-naphthalene]Oxyl, 9,9- Bis[5-(2-(2-(3-(meth)acryloxy-2-hydroxypropoxy)ethoxy)ethoxy)-1-naphthalene] 9,9-bis[ (3-(meth)acryloxy-2-hydroxypropoxy)di-deca C _2-4 alkoxynaphthalene] fen, etc.

These epoxy (meth)acrylates can also form molecular aggregates individually or in combination of 2 or more types. Preferred (meth)acrylic acid epoxy group ester can enumerate: in aforementioned formula (1a), ring Z ^1a and ring Z ^1b are benzene ring or naphthalene ring, n1 and n2 are respectively the compound of 2 to 10, that is, 9,9-bis[(3-(meth)acryloyloxy-2-hydroxypropoxy)polyalkoxyphenyl]oxanes; 9,9-bis[(3-(meth)acryloyloxy) Oxy-2-hydroxypropoxy) polyalkoxy naphthalene] fennels.

Among these (meth)acrylate epoxy esters, the aforementioned (1a-5)9,9-bis[4-(2-(2-(3-(meth)acryloxy-2 -Hydroxypropoxy) ethoxy) ethoxy) phenyl] 9,9-bis[(3-(meth)acryloxy-2-hydroxypropoxy) two to ten C _{2- 4} alkoxyphenyl] fennel; (1a-6) 9,9-bis[4-(2-(2-(3-(meth)acryloxy-2-hydroxypropoxy)ethoxy ) Ethoxy) -3-methylphenyl] 9,9-bis[(3-(meth)acryloxy-2-hydroxypropoxy) two to ten C _2-4 alkoxy -mono- or di-C _1-4 alkylphenyl] fluorine; (1a-8)9,9-bis[4-(2-(2-(3-(meth)acryloxy-2-hydroxypropane Oxy) ethoxy) ethoxy) -3-phenylphenyl] 9,9-bis [(3-(meth)acryloxy-2-hydroxypropoxy) two to ten C _2-4 alkoxy-C _6-10 arylphenyl] fluorine; (1a-9) 9,9- bis [6-(2-(2-(3-(meth)acryloxy-2 -Hydroxypropoxy)ethoxy)ethoxy)-2-naphthalene]fen, 9,9-bis[5-(2-(2-(3-(meth)acryloxy-2-hydroxy Propoxy) ethoxy) ethoxy-1-naphthalene] 9,9-bis[(3-(meth)acryloxy-2-hydroxypropoxy) two to ten C _2-4 Alkoxynaphthalene] terpene.

Furthermore, among the aforementioned (meth)acrylic acid epoxy esters, preferably in the aforementioned formula (1a), ring Z ^1a and ring Z ^1b are benzene rings, R ^1a and R ^1b are alkyl groups, m1 and m2 are Compounds from 0 to 2, that is, the aforementioned (1a-5)9,9-bis[4-(2-(2-(3-(meth)acryloxy-2-hydroxypropoxy)ethoxy 9,9-bis[(3-(meth)acryloxy-2-hydroxypropoxy) two to ten C _2-4 alkoxyphenyl] fen ; (1a-6)9,9-bis[4-(2-(2-(3-(meth)acryloxy-2-hydroxypropoxy)ethoxy)ethoxy)-3- 9,9-bis[(3-(meth)acryloxy-2-hydroxypropoxy)two to ten C _2-4 alkoxy-mono or two C _1-4 Alkylphenyl] fennel.

The ratio of the (meth)acrylic epoxy group represented by the aforementioned formula (1a) can also be 50 to 100 mole % in the (meth)acrylic epoxy group represented by the aforementioned formula (1), compared with It is preferably 70 to 100 mol%, more preferably 80 to 100 mol%, more preferably 90 to 100 mol%, most preferably 100 mol%.

[Manufacturing method of epoxy (meth)acrylate]

The method for producing epoxy (meth)acrylate represented by the aforementioned formula (1) is not particularly limited as long as the addition number of oxyalkylene groups (that is, n1+n2) is adjusted within a predetermined range, and can be used The usual method. In particular, the method for producing epoxy (meth)acrylate represented by the aforementioned formula (1a) may be, for example, a method of reacting an epoxy compound represented by the following formula (3) with a (meth)acrylic component (A). In addition, the epoxy compound represented by said formula (3) can be manufactured by the method etc. which were described in Unexamined-Japanese-Patent No. 2009-155256.

[chemical 5]

(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 , and k are the same as above)

Furthermore, it may also be a method (B) of reacting the first hydroxy compound represented by the following formula (4) with glycidyl (meth)acrylate, such as that described in Japanese Patent Application Laid-Open No. 2004-83855 method.

[chemical 6]

(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 , and k are the same as above)

From the viewpoint of reactivity, etc., preparation is usually carried out by the method (A) in many cases. In addition, the epoxy compound represented by the aforementioned formula (3) used in the aforementioned method (A) can be a commercially available product, or by a conventional method, for example, the first epoxy compound represented by the aforementioned formula (4) can be used. Prepared by reacting a hydroxy compound with epihalohydrin such as epichlorohydrin or epibromohydrin. Therefore, when the (meth)acrylic acid epoxy group represented by the aforementioned formula (1a) is prepared by any method in method (A) or (B), by adding the aforementioned formula (4) to 1 The oxyalkylene addition number (n1+n2) of the hydroxy compound is controlled within a predetermined range, and the epoxy compound represented by the aforementioned formula (3) and the (meth)acrylic epoxy compound represented by the aforementioned formula (1a) can also be adjusted. The oxyalkylene addition number (n1+n2) in the base ester. Furthermore, the epoxy compound represented by the aforementioned formula (3) and the first hydroxyl compound represented by the aforementioned formula (4) may also be molecular aggregates, and the respective oxyalkylene addition numbers (n1+n2) may also be Like the epoxy (meth)acrylate represented by the above-mentioned formula (1a), it is the average value of the aggregate of molecules.

(the first hydroxy compound represented by the aforementioned formula (4))

In the aforementioned formula (4), 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 , R ⁴ , and k are each preferably The aspects and the like are the same as those described above. The representative first hydroxy compound represented by the above-mentioned formula (4) includes, for example, the compound (1a-1) corresponding to the representative example of the epoxy (meth)acrylate represented by the above-mentioned formula (1a). A hydroxy compound to (1a-9), that is, a compound in which 3-(meth)acryloyloxy-2-hydroxypropyl is substituted with a hydrogen atom. These compounds may be contained alone or in combination of two or more species as a molecular aggregate.

The first hydroxy compound represented by the aforementioned formula (4) is not particularly limited, and commercially available products can be used, or by conventional methods, for example, the 2nd hydroxy compound represented by the following formula (5) and the compound corresponding to the aforementioned The oxyalkylene group OA ^1a and OA ^1b in the formula (4) can be prepared by the method of reacting the alkylene oxide or alkylene carbonate, etc. As a specific production method, the method described in Patent Document 5 (Japanese Unexamined Patent Application Publication No. 2017-186513 ) and the like can be used.

(In the formula, n3 and n4 represent 0 or 1 respectively, ring Z ^1a and ring Z ^1b , A ^1a and A ^1b , R ^1a and R ^1b , m1 and m2, R ⁴ , and k are the same as above)

(method (A))

By means of the epoxy compound represented by the aforementioned formula (3) and the method (A), the specific manufacturing method of the (meth)acrylic epoxy group represented by the aforementioned formula (1a) can be utilized in Patent Document 5 (Japanese The method described in JP-A-2017-186513, etc.

Furthermore, in the present invention, since the addition number (n1+n2) of the oxyalkylene group is adjusted within a predetermined range, it has a relatively low viscosity and is excellent in handleability. The viscosity of epoxy (meth)acrylate represented by the aforementioned formula (1a) at a temperature of 25°C can be selected from the range of about 5,000 to 150,000 mPa‧s, For example, 10000 to 60000 mPa‧s, preferably 20000 to 50000 mPa‧s, more preferably 30000 to 45000 mPa‧s, most preferably 35000 to 40000 mPa‧s.

In addition, in this specification and the scope of the patent application, the viscosity system can use a TV-22 type viscometer (Cone & Plate type, "TVE-22L" manufactured by Toki Sangyo Co., Ltd.) at 25°C and select according to the viscosity measurement Rotor (01: 1°34'×R24, 07: 3°×R7.7) is measured at 1 to 20 rpm (selected according to viscosity).

[hardening composition]

The aforementioned epoxy (meth)acrylate may be used alone, or may be mixed with other components such as ultraviolet absorbers, polymerization initiators, other polymerizable compounds, and solvents to form curable compositions.

(ultraviolet absorber)

The curable composition which is one of the preferred aspects of the present invention may also contain an ultraviolet absorber. As the ultraviolet absorber, conventional ultraviolet absorbers can be used.

The curable composition containing an ultraviolet absorber has excellent light resistance, and as will be described later, it can effectively function as a polarizer protective film by being laminated on the surface of a polarizing plate. In order to prevent iodine from being degraded by ultraviolet rays, the polarizer protective film must block ultraviolet rays with a wavelength below 380nm. In order to satisfy such a request, it is effective to add an ultraviolet absorber having a maximum absorption wavelength at 320 to 400 nm called UVA. Such ultraviolet absorbers include, for example, oxybenzophenone-based compounds, benzotriazole-based compounds, triazine-based compounds, and the like.

Examples of oxydiphenyl ketone compounds include: 2,4-dihydroxydiphenyl ketone; 2-hydroxy-4-methoxydiphenyl ketone, 2-hydroxy-4-pentyloxydiphenyl ketone , 2-hydroxy-4-octyloxydiphenyl ketone, 2-hydroxy-4-octyloxy-4'-methoxydiphenyl ketone and other hydroxyl C _1-18 alkoxy diphenyl ketones; 2 _-Hydroxy cycloalkoxy diphenyl ketones such as -hydroxy-4-cyclohexyloxydiphenyl ketone; Halogenated diphenyl ketones. These oxybenzophenone compounds can be used alone or in combination of two or more. As a commercially available product, ADK STAB1413 of ADEKA Co., Ltd., Chimassorb 81 of BASF Japan Co., Ltd., etc. can be used. Among them, from the viewpoint of easiness of preparing a uniform composition, oxybenzophenones having a linear alkyl group having 2 or more carbon atoms such as 2-hydroxy-4-octyloxybenzophenone compound is better. The carbon number of the linear alkyl group with a carbon number of 2 or more can be selected from the range of 2 to 18, and the preferred range is as follows: 3 to 16, 4 to 14, 5 to 12, 6 to 10, the most optimal 7 to 9.

In addition, in this specification and the scope of the patent application, the straight-chain alkyl group is used in the sense that it also includes the straight-chain alkyl group contained in the branched chain alkyl group (for example, ethyl group and n-butyl group in 2-ethylhexyl).

Examples of benzotriazole compounds include: 2-(2H-benzotriazol-2-yl)-4-methyl-phenol, 2-(2H-benzotriazol-2-yl)-4-th Tributyl-phenol, 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)-phenol, 2-(2H-benzotriazole -2-yl)-4-methyl-6-dodecyl-phenol and other benzotriazol-2-yl-C _1-18 alkyl-phenol; 2-(2H-benzotriazol-2-yl )-4,6-bis(1-phenylethyl)phenol and other benzotriazol-2-yl-bis(phenyl C _1-18 alkyl)-phenol; 2-(2H-benzotriazole- 2-yl)-4,6-bis(1-methyl-1-phenylethyl)-phenol isobenzotriazol-2-yl-bis(C _1-18 alkyl-phenyl C _1-18 Alkyl)-phenol; 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethyl butyl) phenol etc. benzotriazol-2-yl-(C _1-18 alkyl-phenyl C _1-18 alkyl)-C _1-18 alkyl-phenol; 2-(5-chloro-2H -Benzotriazol-2-yl)-6-(1,1-dimethylethyl)-4-methyl-phenol and other halobenzotriazol-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(benzene Triazol-2-yl-C _1-18 alkyl-phenol); 2-(2-Hydroxy-3-α-cumyl (cumyl)-5-dodecylphenyl)-2H-benzo 2-(Hydroxy-α-cumyl (cumyl)-5-C _1-18 alkyl-phenyl)-2H-benzotriazole; 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-benzotriazol-2-yl)phenyl]propionate, 2-ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5- Chloro-2H-benzotriazol-2-yl)phenyl]propionate etc. C _1-18 alkyl-[C _1-18 alkyl-hydroxyl-((halogen)-2H-benzotriazole-2 -yl)phenyl]C _2-4 acylate and the like.

These benzotriazole-based compounds can be used alone or in combination of two or more. Commercially available benzotriazole compounds include Tinuvin P, Tinuvin 234, Tinuvin 326, Tinuvin 329, Tinuvin 360, Tinuvin 571, Tinuvin 99-2, Tinuvin 213, Tinuvin 900, and Tinuvin 928 from BASF Japan Co., Ltd.; ADK STABLA-31 from ADEKA Co., Ltd.; Eversorb89, Eversorb109, EversorbBL1A from Everlight Chemical, etc.

Among these benzotriazole compounds, octyl-3-[3-tert-butyl-4-hydroxyl-5-(5-chloro-2H Benzotriazole-based compounds having a straight-chain alkyl group having 2 or more carbon atoms, such as -benzotriazol-2-yl)phenyl]propionate, are preferred. The carbon number of the linear alkyl group with a carbon number of 2 or more can be selected from the range of 2 to 18, and the preferred range is as follows: 3 to 16, 4 to 14, 5 to 12, 6 to 10, the most optimal 7 to 9.

Examples of triazine compounds include: 2-(4-hexyloxy-2-hydroxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2-[4-[(2 -Hydroxy-3-(2'-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine iso(hydroxy-C _1-18 alkoxy-hydroxyphenyl)bis(di-C _1-18 alkyl-phenyl)-1,3,5-triazine; 2,4-bis(2-hydroxy-4 -Butoxy-phenyl)-6-(2,4-dibutoxy-phenyl)-1,3,5-triazine and other bis(hydroxy-C _1-18 alkoxy-phenyl)- ( _{DiC 1-18} alkoxy-phenyl)-1,3,5-triazine; 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1 , 3,5-triazine, etc. Tris(hydroxy-C _1-18 alkoxy-C _1-18 alkyl-phenyl)-1,3,5-triazine, etc. These triazine compounds can be used alone or in combination of two or more. As commercially available products, Tinuvin 405 and Tinuvin 460 of BASF Japan Co., Ltd.; ADK STABCA-F70 of ADEKA Co., Ltd., etc. can be used. Among these, 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5- Oxybenzophenone compounds having a straight-chain alkyl group having 2 or more carbon atoms, such as triazine, are preferable. The carbon number of the linear alkyl group with a carbon number of 2 or more can be selected from the range of 2 to 18, and the preferred range is as follows: 3 to 16, 4 to 14, 5 to 12, 6 to 10, the most optimal 7 to 9.

These ultraviolet absorbers can be used alone or in combination of two or more. Among these ultraviolet absorbers, benzotriazole-based compounds are preferred, and benzotriazole-based compounds having a straight-chain alkyl group having 4 or more carbon atoms are preferred from the standpoint of easiness in preparing a uniform composition. good. Among them, C _4-12 alkyl-[C _2-16 alkyl-hydroxyl-(halo-2H-benzotriazol-2-yl) phenyl] C _2-4 acylate is preferred, and C _{4- 10} Alkyl-[branched C _3-12 alkyl-hydroxy-(halo-2H-benzotriazol-2-yl)phenyl]C _3-4 acylate is particularly preferred.

The type and amount of the ultraviolet absorber can be set in the most appropriate range according to the absorption spectrum and molar absorption coefficient of the ultraviolet absorber and the compatibility with the curable resin composition. Specifically, according to the total light transmittance (JIS K7361), the light transmittance at 380nm (JIS K7105), the haze (JIS K7136), and the yellowness (YI) of the cured film (JIS K7373) evaluation results to determine. It is not limited to the following values, but the total light transmittance is preferably above 85%, more preferably above 88%, and most preferably above 89%. The light transmittance at 380nm is preferably lower, for example, preferably less than 20%, more preferably less than 10%, and most preferably less than 8%. The haze is preferably a lower value, for example, it is more preferably 1% or less. The YI system takes 1 or less as the evaluation benchmark. It is better for the maximum absorption wavelength to be close to 380nm, but it is unfavorable that the yellow coloring becomes stronger when it is close to 400nm. In order to set the light transmittance at 380nm below 10%, if the molar absorptivity at 380nm is too low, it is not good because the added amount increases, or insoluble matter forms haze, or bleeds out.

Relative to the total amount of (meth)acryl group-containing components in the curable composition (for example, the total amount of epoxy (meth)acrylate represented by the aforementioned formula (1) and other polymerizable compounds described later etc.) 100 parts by mass, the ratio of the ultraviolet absorber is, for example, 0.1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, The best is 0.8 to 5 parts by mass, and the best is 1 to 3 parts by mass. In particular, from the viewpoint of improving the ultraviolet shielding performance even when added in a small amount and having excellent properties such as optical properties and mechanical properties, relative to the total amount of components containing (meth)acryl groups in the curable composition, The ratio of the ultraviolet absorber is, for example, 0.6 to 3 parts by mass, preferably 0.7 to 2 parts by mass, more preferably 0.8 to 1.5 parts by mass, more preferably 0.9 to 1.2 parts by mass, most preferably 0.9 to 1.1 parts by mass. When the ratio of the ultraviolet absorber is too small, the effect of improving the light resistance may not be exhibited, and conversely, when the ratio is too large, the mechanical properties of the cured product may be lowered.

(polymerization initiator)

The curable composition which is one of the preferred aspects of the present invention may contain a thermal polymerization initiator and/or a photopolymerization initiator. Thermal polymerization initiators include organic peroxides, azo compounds, and the like. Organic peroxides can be, for example: dialkyl peroxides such as di-tert-butyl peroxide; diacyl peroxides such as lauryl peroxide and benzoyl peroxide; Peroxyacids (or peresters) such as tributyl hydroperoxide, cumene hydroperoxide, tertiary butyl peracetate; ketone peroxides; peroxycarbonates; peroxy Ketals, etc. Examples of the azo compound include azonitrile compounds such as 2,2-azobis(isobutyronitrile); azoamide compounds; azoamidine compounds, and the like. These thermal-polymerization initiators can be used individually or in combination of 2 or more types.

The photopolymerization initiator (or photoradical polymerization initiator) can be for example: benzoin such as benzoin; benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin phenyl ether Benzoin alkyl ethers; acetophenone, 3-hydroxyacetophenone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-hydroxy-2-methyl- 1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane- 1-keto, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-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-mol Linylpropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane-1-one, 2-dimethylamino-2- (4-Methylbenzyl)-1-(4-morpholinyl-4-yl-phenyl)-butane -1-ketone and other aminoacetophenones; anthraquinone, anthraquinone-2-sulfonate, 2-ethylanthraquinone and other anthraquinones; thioxanthone, isopropoxychlorothioxanthone, 2- Chlorthioxanthone, 2,4-dimethylxanthone and other thioxanthones; acetophenone dimethyl ketal, benzyl dimethyl ketal and other ketals; diphenyl ketone, 4-hydroxy Diphenyl ketone, 4,4'-dihydroxydiphenyl ketone, 4,4'-dichlorodiphenyl ketone, 3-methyl diphenyl ketone, 4-phenyl diphenyl ketone and other diphenyl Ketones; 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer 2,4,5-triaryl imidazole dimers; Oxanthones; 2,4,6-trihalomethyl triazines; 9-phenylacridine, 1,7-bis(9,9 Acridine derivatives such as '-acridyl) heptane; bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl) Acylphosphine oxides such as -2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, etc. These photopolymerization initiators can be used alone or in combination of two or more.

When the curable composition contains an ultraviolet absorber that absorbs ultraviolet rays with a wavelength shorter than 400nm, in order to efficiently perform photocuring by using visible light, the photopolymerization initiator preferably contains Absorption wavelength) photopolymerization initiator (a photopolymerization initiator having an absorption wavelength in the long wavelength region), particularly preferably a photopolymerization initiator having an absorption wavelength in the long wavelength region and a photopolymerization initiator having a critical value at less than 400nm A combination of photopolymerization initiators (photopolymerization initiators having an absorption wavelength in a short wavelength region).

In terms of photopolymerization initiators (long-wavelength photopolymerization initiators) having absorption wavelengths in the long-wavelength region, among the aforementioned photopolymerization initiators, for example: aminoacetophenones (α-amino Acetophenone compounds), acyl phosphine oxides, etc. Commercially available aminoacetophenones include, for example, IRGACURE 369, IRGACURE 379, and IRGACURE 907 from BASF Japan Co., Ltd. Commercially available acyl phosphine oxides can be used, for example: IRGACURE 819 (bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide) from BASF Japan Co., Ltd., IRGACURE 1800 ( bis(2,6-dimethoxybenzyl Acyl) phosphine oxide), DAROCUR TPO, etc. Among these, acylphosphine oxide compounds such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide are preferable.

As for the photopolymerization initiator having an absorption wavelength in the short wavelength region (short-wavelength photopolymerization initiator), among the aforementioned photopolymerization initiators, for example: aminoacetophenones and acylphosphine oxides Other photopolymerization initiators, etc. Among the aforementioned photorestarters, acetophenones such as 1-hydroxycyclohexyl phenyl ketone are preferable. As commercially available acetophenones, for example, IRGACURE 184 [phenyl(1-hydroxycyclohexyl)ketone] of BASF Japan Co., Ltd. can be used.

Relative to the total amount of (meth)acryl group-containing components in the curable composition (for example, the total amount of epoxy (meth)acrylate represented by the aforementioned formula (1) and other polymerizable compounds described later, etc. ) 100 parts by mass, the ratio of the polymerization initiator (thermal and/or photopolymerization initiator) is, 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, the best It is 2 to 5 parts by mass. Among these polymerization initiators, it is preferable to contain at least a photopolymerization initiator.

When combining a short-wavelength photopolymerization initiator and a long-wavelength photopolymerization initiator, the ratio of the long-wavelength photopolymerization initiator to 100 parts by mass of the short-wavelength photopolymerization initiator may be 1 part by mass or more, for example, 1 to 200 parts by mass, preferably 5 to 150 parts by mass, more preferably 10 to 100 parts by mass, most preferably 20 to 50 parts by mass. When the ratio of the long-wavelength photopolymerization initiator is too small, when the curable composition contains an ultraviolet absorber, the photocurability may decrease.

Furthermore, the photopolymerization initiator can also be combined with a photosensitizer. The photosensitizer may also be a commonly used photosensitizer such as tertiary amines. Tertiary amines include, for example: trialkylamines; trialkanolamines such as triethanolamine; ethyl N,N-dimethylaminobenzoate, amyl N,N-dimethylaminobenzoate Alkylamino benzoic acid alkyl esters: 4,4-bis(dimethylamino)diphenyl ketone, 4,4-bis(diethylamino)diphenyl ketone and other bis(dialkylamines) base) diphenyl ketone; 4-(dimethylamino) diphenyl ketone, 4-methoxy-4'-dimethylamino dialkylaminodiphenyl ketones such as diphenyl ketones and the like. These photosensitizers can be used alone or in combination of two or more. When the curable composition contains an ultraviolet absorber that absorbs ultraviolet rays having a wavelength shorter than 400 nm, the photosensitizer is preferably a photosensitizer having an absorption wavelength at 400 to 450 nm.

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

(other polymeric compounds)

The curable composition which is one of the preferred aspects of the present invention may further contain a polymerizable compound having one or more polymerizable functional groups in the molecule, thereby improving sensitivity (or curability), Fluidity, chemical resistance, heat resistance or mechanical strength, etc. Other polymeric compounds can also be polymeric compounds with vinyl groups, but most of them are monofunctional or polyfunctional (meth)acrylates with (meth)acryl groups.

Monofunctionality (meth)acrylic acid ester can for example: (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate; Hydroxyalkyl (meth)acrylates such as hydroxyethyl methacrylate; alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate; cyclohexyl (meth)acrylate Cycloalkyl (meth)acrylates such as esters; Aryl (meth)acrylates such as phenyl (meth)acrylates; Aryloxy (meth)acrylates such as phenoxyethyl (meth)acrylates Alkyl esters; Aralkyl (meth)acrylates such as benzyl (meth)acrylates; Aryloxy ((meth)acrylates) such as phenoxyethoxyethyl (meth)acrylates Alkoxy)alkyl esters; alkylaryloxyalkyl (meth)acrylates such as nonylphenoxyethyl (meth)acrylates; nonylphenoxy (poly)ethyl (meth)acrylates Alkylaryloxy(poly)alkoxyalkyl (meth)acrylates such as oxyethyl esters; (meth)acrylic acids such as 2-(o-phenylphenoxy)ethyl (meth)acrylates Arylaryloxyalkyl esters; arylaryloxy (poly)alkoxyalkyl (meth)acrylates such as phenylphenoxy (poly)ethoxyethyl (meth)acrylates; ( Methylthio methacrylate Alkylthio (meth)acrylates, etc. Arylthio (meth)acrylates, such as phenylthio (meth)acrylates, Aralkyl (meth)acrylates, such as benzylthio (meth)acrylates (meth)arylthioalkyl esters such as phenylthioethyl (meth)acrylates; (meth)arylthioalkyl esters; N,N-dimethylaminoethyl (meth)acrylates etc. N,N - Dialkyl(meth)acrylamide; mono(meth)acrylate of bisphenols such as ethylene oxide adducts of bisphenol A or their adducts of alkylene oxides ) acrylates; 9-(meth)acryloyloxymethyl fluorine and other (meth)acrylates with a fluorine skeleton.

Polyfunctional (meth)acrylates can be roughly classified into difunctional (meth)acrylates and trifunctional or higher (meth)acrylates. Examples of difunctional (meth)acrylates include (poly)C _{2 -4} alkanediol di(meth)acrylate; bisphenol A (or its alkylene oxide adduct) di(meth)acrylate, 9,9-bis[4-(2-(meth) base) acryloxy (poly) ethoxy) phenyl] fen, etc. Examples of (meth)acrylates with more than three functionalities: glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, neopentylthritol tri(meth)acrylate, neopentyl tri(meth)acrylate, Three to six (meth)acrylates of tri to hexaols ]; urethane (meth)acrylate; 3 to 6 functional (meth)acrylates with a fennel skeleton [eg, 9,9-bis[4-(2-(meth)acryloxy( Poly) ethoxy) phenyl] fennel, etc.] and so on.

These monofunctional and polyfunctional (meth)acrylates can also be used individually or in combination of 2 or more types.

With respect to 100 parts by mass of epoxy (meth)acrylate represented by the aforementioned formula (1), the ratio of these polymerizable compounds can be selected from the range of, for example, about 0 to 50 parts by mass, preferably 0 to 30 parts by mass Parts, preferably 0 to 20 parts by mass, most preferably 0 to 10 parts by mass.

(other additives)

烷(dioxane)等環狀醚；甲基賽路蘇乙酸酯、丙二醇單甲基醚乙酸酯等伸烷基二醇單烷基醚乙酸酯類；乙酸乙酯等酯類；乙腈等腈類；二甲基甲醯胺、二甲基乙醯胺等醯胺類；亞碸類；己烷、庚烷等脂肪族烴；環己烷等脂環族烴；甲苯、二甲苯、乙基苯等芳香族烴類；二氯甲烷、三氯甲烷、1,2-二氯乙烷等鹵系烴等。此等之溶劑亦能夠單獨或2種以上組合成混合溶劑使用。 Furthermore, the aforementioned curable composition may also contain a solvent as needed. The solvent is not particularly limited, and examples thereof include dialkyl ketones such as acetone, diisopropyl ketone, and methyl isobutyl ketone; cyclic ketones such as cyclohexanone; and chain ketones such as diethyl ether and diisopropyl ether. Ether; tetrahydrofuran, two

Cyclic ethers such as alkane (dioxane); alkylene glycol monoalkyl ether acetates such as methyl celuco acetate and propylene glycol monomethyl ether acetate; esters such as ethyl acetate; nitriles such as acetonitrile Amides such as dimethylformamide, dimethylacetamide, etc.; Azolides; Aliphatic hydrocarbons such as hexane and heptane; Alicyclic hydrocarbons such as cyclohexane; Toluene, xylene, ethyl Aromatic hydrocarbons such as benzene; Halogenated hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane, etc. These solvents can also be used alone or in combination of two or more kinds as a mixed solvent.

Furthermore, the above-mentioned curable composition can also contain conventional additives, such as colorants, stabilizers, polymerization inhibitors, fillers, antistatic agents, flame retardants, interfacial agents, as long as they do not impair the effects of the present invention. Active agent, plasticizer, defoamer, coupling agent, etc. Examples of the aforementioned stabilizer include heat stabilizers, antioxidants, and the like. These additives can be used alone or in combination of two or more. The total ratio of additives is, for example, 0.1 to 20 parts by mass, preferably 0.5 to 10 parts by mass relative to 100 parts by mass of the total amount of epoxy (meth)acrylate represented by the aforementioned formula (1) and other polymerizable compounds parts, preferably 1 to 5 parts by mass.

[hardened object]

The aforementioned curable composition is easily cured by imparting active energy (active energy ray). Among the above-mentioned active energy, heat energy and/or light energy are useful, and can be appropriately selected according to the purpose and the like. The light energy can be, for example, ultraviolet rays, electron rays, X-rays, and the like.

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

Furthermore, when using light energy such as ultraviolet rays, the light irradiation energy can be appropriately selected according to the application, for example, 50 to 10000mJ/cm ² , preferably 70 to 8000mJ/cm ² , and more preferably 100 to 5000mJ/cm ² , most preferably The best is 300 to 3000mJ/cm ² . The light source can use laser light sources such as Deep UV lamp, low-pressure mercury lamp, high-pressure mercury lamp, ultra-high pressure mercury lamp, halogen lamp, helium-cadmium laser or excimer laser, etc.

In addition, even in the case of hardening by light irradiation, heat treatment such as baking treatment or post-baking may be performed in order to improve reactivity. The temperature and time of the heat treatment are the same as those of the aforementioned heat energy utilization. Furthermore, the reaction (or polymerization, cross-linking or hardening) can be carried out in the atmosphere or an inert gas environment, and can also be carried out under normal pressure, increased pressure or reduced pressure. For example, the inert gas environment can be nitrogen environment, rare gas environment such as helium and argon, etc.

One of the preferred aspects of the present invention is that the cured product has unexpectedly high hardness despite the introduction of a highly flexible oxyalkylene group, and can balance the contradictory characteristics of high hardness and flexibility. The reason for this is not yet determined, but it is presumed to be due to the formation of a hydrogen bond between the introduced oxyalkylene group and the hydroxyl group of the epoxy (meth)acrylate. Generally, when an oxyalkylene group is introduced, the cured product will form a structure that is easy to bend and the crosslink density will also decrease, so the flexibility of the cured product tends to be greatly improved. Therefore, the hardness which is opposite to the softness will be greatly reduced. However, it is estimated that in the epoxy (meth)acrylate represented by the aforementioned formula (1), there is a hydroxyl group (the hydroxyl group adjacent to the (meth)acryl group) in the side chain, and the addition number of the oxyalkylene group is (n1+n2) is adjusted within a predetermined range, therefore, the oxyalkylene group is also easier to move in the hardened product, and the oxygen atom of the oxyalkylene group and the aforementioned hydroxyl group become easy to form hydrogen bonds to form a pseudo-crosslink point, and increase the crosslink density and hardness. In addition, when the crosslink density and hardness increase, the original flexibility will generally be lost. However, in the cured product of one of the preferred aspects of the present invention, it is speculated that due to the low binding energy of hydrogen bonds, it is more than a certain degree. The bond is easily disintegrated (the cross-link density is reduced) when the external force acts on it, showing The flexibility derived from the oxyalkylene group forms a new hydrogen bond when the external force is removed, so it can have both high hardness and flexibility.

[Optical film]

Hereinafter, an embodiment of a manufacturing method of an optical film (a cured film formed of a cured product of the aforementioned curable composition) which is one of the preferred aspects of the present invention will be described.

Fig. 1 is a schematic diagram of the manufacturing steps of an optical film according to one of the preferred aspects of the present invention. Since the curable composition used as the raw material of the optical film is liquid, a known coating device can be used. As shown in FIG. 1 , the curable composition 3 is cast on the support film 2 unwound from the unwinding device 1 in a film form by the coating head 4 . The cast-coated curable composition 3 is cured by irradiating a predetermined amount of light with an ultraviolet ray irradiation device 5, and the cured film-like cured product (cured film) 7 is peeled off from the support film 2 by a take-up device 6, and Cured film winding device 8 winds up.

The method of casting the aforementioned curable composition is not particularly limited as long as it is capable of being used in the technical field of the present technology, and it can be used: bar coating method, knife coating method, roll coating method, roll coating method, etc. ) coating method, blade coating method, die coating method, micro gravure coating method, comma coating method, slot die (slot die) Coating method, lip coating method, solution casting method, etc.

The aforementioned curable composition is preferably liquid, and can be used after viscosity adjustment or the like using a solvent as a diluent. For example, the addition method of the ultraviolet absorber is that the ultraviolet absorber can be dissolved in alcohols such as methanol, ethanol, butanol; organic solvents such as dichloromethane, methyl acetate, acetone, dioxolane (dioxolane) or the like Add it in the state of a solution in a mixed solvent of the same. However, at this time, considering that it takes time to remove the volatilization of the solvent, the production efficiency is reduced, and the characteristics of the formed film are reduced due to the residual solvent in the cured film, etc., so the curable composition to be coated The content of the solvent is preferably limited to 5% by mass or less, it is particularly preferable to use a composition that does not contain a solvent substantially, and it is most preferable to use a composition that does not contain a solvent.

The support film is selected by evaluating the smoothness of the surface, the wettability with the curable composition, the detachability of the cured film, and the transferability. As the support film, polyester resins, polyolefin-based resins, vinyl chloride resins, acetylcellulose resins, acrylic resins, vinyl fluoride resins, polycarbonate resins, polyamide resins, Films of polyphenylene ether-based resins, cycloolefin-based resins, etc. Among them, polyester-based resins, especially polyethylene terephthalate (PET) films, which are excellent in surface smoothness and have a balance of other characteristics are preferable.

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

The end of the hardened film can be cut with a cutting machine to remove the appropriate width due to the occurrence of deflection due to wrinkles or hardening shrinkage.

The pencil hardness of the optical film (cured film) of one of the preferred aspects of the present invention is, for example, H or higher, preferably 2H or higher, and more preferably 3H or higher. When the pencil hardness is too low, there is a possibility that protective functions such as abrasion resistance may be lowered when used as a cover sheet. In addition, in this specification and the scope of the patent application, the pencil hardness can be measured according to the method of JIS K5600-5-4. Specifically, it can be measured by the method described in the following examples.

The aforementioned optical film system has excellent bending stability, and it is difficult to form bending inertia and adherent creases. The bending stability of the aforementioned optical film is, for example, 2 mm or less, preferably 1 mm or less, and more preferably 0.5 mm or less. When the bending stability is too low, deformation such as bending inertia may occur due to being left in a bent state for a long time. In addition, in this specification and the scope of the patent application, the bending stability system can be described in Patent Document 4 (Japanese The method disclosed in this Japanese Patent Laid-Open Publication No. 2019-051718) can be evaluated, and in detail, it can be measured by the method described in the examples below.

The aforementioned optical film system is excellent in bending durability, and can suppress the occurrence of creases or breakage even when it is bent repeatedly. The bending durability of the aforementioned optical film may be, for example, 100,000 or more, preferably 300,000 or more, and most preferably 500,000 or more. When the bending durability is too low, creases or breakage may be generated when bending is repeated. In this specification and the claims, the bending durability can be measured by the method described in the examples below.

The aforementioned optical film system is excellent in transparency. The total light transmittance of the aforementioned optical film can be above 80%, such as 80 to 100%, preferably 83 to 99%, more preferably 85 to 98%, most preferably 88 to 95%. In the case where the aforementioned optical film contains an ultraviolet absorber, the total light transmittance is more than 85%, preferably more than 87%, more preferably more than 88%, and most preferably more than 89%. In addition, in this specification and the claims, the total light transmittance can be measured according to JIS K7361-1, and in detail, it can be measured by the method described in the Example mentioned later.

The light transmittance of the aforementioned optical film with a wavelength of 380nm can be more than 50%, such as 50 to 100%, preferably 60 to 95%, more preferably 70 to 90%, most preferably 80 to 85%. When the aforementioned optical film contains an ultraviolet absorber, the aforementioned spectral light transmittance may be less than 50%, such as less than 30%, preferably less than 10%, and more preferably less than 8%. In addition, in this specification and the scope of the patent application, the spectral light transmittance can be measured by the method described in the following examples.

The yellowness (YI) of the aforementioned optical film may be less than 10, such as 0.1 to 10, preferably 0.3 to 8, more preferably 0.5 to 5, more preferably 1 to 3.5, most preferably 1.5 to 2.5. In the case where the aforementioned optical film contains an ultraviolet absorber, the yellowness is, for example, 10 or less, preferably 8 or less, more preferably 7 or less, most preferably 6 or less Down. In addition, in this specification and claims, yellowness can be measured based on JIS K7373, Specifically, it can measure by the method described in the Example mentioned later.

The haze of the aforementioned optical film may be less than 10%, such as 0.1 to 10%, preferably 0.2 to 5%, more preferably 0.3 to 3%, more preferably 0.5 to 2%, most preferably 0.7 to 1.5%. When the aforementioned optical film contains an ultraviolet absorber, the haze is 5% or less, preferably 3% or less, more preferably 1% or less, most preferably 0.5% or less. In addition, in this specification and the claims, the haze can be measured based on JIS K7136, and can be measured by the method described in the Example mentioned later in detail.

The refractive index of the aforementioned optical film at 20°C and a wavelength of 589nm can be selected from the range below 1.6, such as 1.52 to 1.6, preferably 1.53 to 1.59, more preferably 1.54 to 1.585, more preferably 1.55 to 1.58, and most preferably 1.56 to 1.57. In addition, in this specification and claims, the refractive index can be measured using a multi-wavelength Abbe refractometer, and in detail, it can be measured by the method described in the examples described later.

The phase difference (birefringence) of the aforementioned optical film is small and does not damage the visibility of the image display device. At room temperature, with a wavelength of 550nm and a thickness of 50μm, the in-plane retardation (or frontal retardation) Ro of the aforementioned optical film is 0 to 10nm, and the preferred range is as follows: 0 to 8nm, 0.01 to 6nm, 0.03 in stages to 5 nm, 0.05 to 4 nm, 0.1 to 3 nm, 0.2 to 2 nm, most preferably 0.3 to 1 nm. When the aforementioned optical film contains an ultraviolet absorber, the aforementioned Ro is, for example, 0 to 5 nm, preferably 0.01 to 3 nm, more preferably 0.03 to 1 nm, most preferably 0.05 to 0.5 nm. When the in-plane phase difference Ro is too large, iridescence or light leakage may occur, and the visibility through polarized sunglasses may decrease.

At room temperature, with a wavelength of 589nm and a thickness of 50μm, the retardation Rth in the thickness direction of the optical film is 0 to 150nm, and the preferred range is as follows: 1 to 100nm, 5 to 80nm, 10 to 70nm, 12 to 60nm , 15 to 50 nm, preferably 20 to 30 nm. In the case where the aforementioned optical film contains an ultraviolet absorber, the aforementioned Rth is, for example, 0 to 10 nm, preferably 0.01 to 5 nm, more preferably 0.05 to 3 nm, The optimum is 0.1 to 1 nm. When the retardation Rth in the thickness direction is too large, iridescence or light leakage may occur, and the visibility through polarized sunglasses may decrease.

The in-plane phase difference Ro and the thickness direction phase difference Rth of the said optical film can be calculated by the following formula, respectively.

Ro=(nx-ny)×d

Rth=((nx+ny)/2-nz)×d

(In the formula, nx represents the refractive index in the direction of the slow axis of the film, ny represents the refractive index in the direction of the fast axis of the film, nz represents the refractive index in the thickness direction of the film, and d represents the thickness of the film).

In addition, in this specification and the claims, the in-plane retardation Ro and the thickness direction retardation Rth can be measured by the method described in the examples described later.

The thickness (average thickness) of the aforementioned optical film is not particularly limited, and it is, for example, 20 to 300 μm, preferably 30 to 250 μm, more preferably 50 to 200 μm, more preferably 70 to 150 μm, most preferably 80 to 120 μm. The thickness (average thickness) of the aforementioned optical film can be, for example, 20 to 200 μm, preferably 30 to 150 μm, and more preferably 50 to 120 μm. Such a thin film contains an ultraviolet absorber in the aforementioned optical film and serves as a polarizer It is especially effective when the protective film is used. When the optical film is too thin, protective functions such as abrasion resistance may be lowered, and conversely, when it is too thick, bending resistance may be lowered.

[Cover sheets for displays]

The aforementioned optical film can also be a cover sheet (or cover film) for a display, especially a cover sheet for a foldable display. When the curable composition contains an ultraviolet absorber, it is preferably used as a laminate A cover sheet for foldable displays (polarizer protective film) that is placed on the surface of the polarizer polarizer and functions as a polarizer protective film. The reason why a cover sheet formed of a cured product of a curable composition containing an ultraviolet absorber is suitable for this purpose is as follows.

Usually, a cover sheet for a foldable or rollable display is bonded to a circular polarizing plate with an adhesive, but in order to withstand bending or rolling back, the circular polarizing plate is coated with thin polyvinyl alcohol ( The PVA) polarizer and the acrylic protective film of the film are bonded together with an adhesive. The acrylic protective film cannot withstand bending if it is about 40 μm thick, which is usually used for polarizing plate protective films, so it is designed to be about half the thickness. In order to protect the iodine of the polarizer (polarizing film) from ultraviolet rays, a UV absorber is added to the polarizer protective film. However, when the thickness becomes thinner, the solubility of the UV absorber to the acrylic resin decreases, so it is easy to ooze out and change. Too much to add the amount needed to absorb UV rays. Therefore, an insufficient amount of ultraviolet absorber is added to the adhesive, resulting in reduced adhesive force. Furthermore, although a foldable display is being studied, it is hoped that it can achieve thinning and bending resistance without a protective film by making the foldable cover sheet also function as the protective film of the polarizer. However, the current situation There is no display that can take into account thinness and ultraviolet absorption ability, and can fully satisfy the adhesion to PVA polarizers.

In contrast, one of the preferred aspects of the present invention is formed of a cured product of a curable composition containing an ultraviolet absorber, so it can achieve both thinning and ultraviolet absorbing ability, and can also improve the adhesion to the PVA polarizer. sex.

The cover sheet for a display which is one of the preferred aspects of the present invention can be directly bonded to a PVA polarizer because it has the function as a protective film for a polarizing plate. Polarizing plate protective film usually must have the function as the support body of soft PVA film, and the above-mentioned covering sheet of one of the preferred aspects of the present invention is a soft film, and does not have the support that can bear the stress caused by the heat shrinkage of PVA body rigidity. However, in a foldable display, the image display device is an OLED, and its circular polarizing plate is composed of a laminate of a coated thin-film PVA layer and an acrylic retardation film. The shrinkage stress of PVA is controlled by the rigidity. The acrylic phase difference film is relieved. Therefore, the above-mentioned cover sheet can be integrally formed into a circular polarizing plate by bonding the PVA layer with an adhesive with strong adhesive force, so it can be adjusted so as not to be affected by the shrinkage stress of PVA.

The adhesive used for laminating the PVA layer can be an active energy ray hardening adhesive. The adhesive can be, for example, a photocationic polymerization type adhesive such as an adhesive composed of an epoxy resin composition containing a photocationic polymerization initiator; (meth)acrylamide, (meth)acrylate Adhesives composed of (meth)acrylic resin compositions such as urethane (meth)acrylate, (meth)epoxy (meth)acrylate, etc., such as photoradical polymerizable adhesives, etc. These adhesives can be used alone or in combination of two or more, and can also be a combination of a photocationic polymerizable adhesive and a photoradical polymerizable adhesive. The cover sheet for a display which is one of the preferred aspects of the present invention is hydrophobic, so the moisture permeability is low, and it takes time to dry the moisture. Therefore, in terms of the aforementioned adhesives, PVA-based water-based adhesives that must be dried with water are unfavorable. Therefore, among the aforementioned adhesives, hydrophobic adhesives are preferred. Furthermore, since the aforementioned adhesive does not require a drying step or drying equipment, it is preferably an adhesive that does not contain an organic solvent.

A cover sheet for a display utilized as a protective film for a polarizing plate can be produced by, for example, applying the aforementioned adhesive with an adhesive coating device, and combining it with a polarizing film coated with a PVA layer on a retardation film. After bonding the guide rollers, irradiating ultraviolet rays from the side of the cured film with an ultraviolet irradiation device to harden the adhesive, etc.

In order to improve adhesion, surface modification treatments such as corona treatment, flame treatment, plasma treatment, ultraviolet treatment, primer coating treatment, and saponification treatment may be applied to the polarizer and/or the cover sheet for a display.

The laminated film obtained by laminating the aforementioned cover sheet for a display and a polarizer is used as a member integrating the cover sheet and the polarizer, and can be mounted on a foldable terminal such as a foldable smartphone.

[Example]

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited by these examples. Hereinafter, the raw materials and evaluation methods used in the examples are as follows.

[raw material]

BPEF-5EOGA: Epoxy acrylate synthesized by the method described in the examples of Japanese Patent Application Laid-Open No. 2017-186513, epoxy acrylate with n1+n2=7 in the aforementioned formula (1b)

BPEF-9EOGA: Epoxy acrylate synthesized by the method described in the examples of Japanese Patent Application Laid-Open No. 2017-186513, epoxy acrylate with n1+n2=11 in the aforementioned formula (1b)

BNEF-13EOGA: Epoxy acrylate synthesized by the method described in the examples of Japanese Patent Laid-Open No. 2017-186513, Z ^1a and Z ^1b in the aforementioned formula (1a) are naphthalene rings and n1+n2=15 epoxy acrylate

BPEF-9EOA: 9,9-bis(4-(2-hydroxyethoxy)phenyl) fluorine (BPEF) 1 mole, the addition of ethylene oxide with an average of 9 moles Finished diacrylate (manufactured by Osaka Gas Chemicals Co., Ltd.)

UV-3200B (ester system): manufactured by Nippon Synthetic Chemical Industry Co., Ltd., difunctional urethane acrylate

Epoxy ester 3000A: manufactured by Kyoeisha Chemical Co., Ltd., an acrylic acid adduct of bisphenol A diglycidyl ether

Ultraviolet absorber A: Eversorb 109, manufactured by Everlight Chemical Co., Ltd., viscous liquid

Ultraviolet absorber B: Eversorb BL1A, manufactured by Everlight Chemical Co., Ltd., viscous liquid

Photopolymerization initiator A: BASF Japan Co., Ltd., trade name "IRGACURE 184"

Photopolymerization initiator B: BASF Japan Co., Ltd., trade name "IRGACURE 819"

Support film: manufactured by TORAY Co., Ltd., trade name "PET Lumirror", film thickness 100 μm.

[Pencil hardness]

The measurement was performed using a pencil hardness tester ("HEIDON-14" manufactured by Shinto Scientific Co., Ltd.) in accordance with JIS K5600-5-4 (load: 750 g).

[bending stability]

The measurement was performed in the following manner using a bending tester ("DMLHP-CS" manufactured by Yuasa System Co., Ltd.). That is, as shown in FIG. 2( a), first, a pair of flat plates (plates) 12, 13 of a testing machine 10 for holding a film 11 are placed so that their respective film mounting surfaces 12a, 13a become on the same plane. The method is fixed, and the film (test piece) 11 is set on the film mounting surfaces 12a, 13a. Next, the flat plate ends 12b, 13b facing each other between the pair of flat plates 12, 13 are used as the rotation centers of the respective flat plates 12, 13, and the two flat plates 12, 13 are relatively moved, thereby making each film mounting surface 12a and 13a move oppositely across a distance R regulated by a spacer (not shown) (hereinafter, this moving operation is referred to as "closing operation"). In this sealing operation, the two flat plates 12, 13 are moved so that the respective film mounting surfaces 12a, 13a finally become opposite and parallel as shown in Fig. 2(b). The interval R between the respective film mounting surfaces 12a and 13a was adjusted to 4 mm.

After the pair of flat plates 12 and 13 are in the state shown in Figure 2(b) by the sealing operation, after standing at room temperature for 24 hours, the film 11 is taken out from the testing machine 10, so that the curved inner side In the method of facing up, the film 11 was placed on a plane and left for 1 hour, and the height of the end of the film 11 floating from the plane was measured.

[bending durability]

Using the above-mentioned bending tester 10, after performing the closing operation with the same bending method as the above-mentioned bending stability test, by making the pair of flat plates 12, 13 relatively move opposite to the closing operation, again as shown in Figure 2 (a) The movement is shown so that the respective film mounting surfaces 12a, 13a become the same plane (hereinafter, this movement The operation is called an "open operation"). Then, a series of operations of this closing operation and opening operation are repeated 100,000 or 1,000,000 times to visually observe the creases on the surface of the film 11, whether there are cracks, etc., and count until the creases or cracks occur on the film. The number of times of bending until an abnormality occurs.

[Full Light Transmittance]

Based on JIS K7361-1, it measured using the color-difference nephelometer ("COH-400" by Nippon Denshoku Co., Ltd.).

[Split light transmittance]

The spectral light transmittance at 380 nm was measured using a spectrophotometer ("UV-3600" manufactured by Shimadzu Corporation).

[Yellowness (YI)]

Based on JIS K7373, it measured using the color-difference nephelometer ("COH-400" by Nippon Denshoku Co., Ltd.).

[haze]

Based on JIS K7136, it measured using the color-difference nephelometer ("COH-400" by Nippon Denshoku Co., Ltd.).

[refractive index]

Using a multi-wavelength Abbe refractometer ("DR-M4 (circulating constant temperature water tank 60-C3)" manufactured by ATAGO Co., Ltd.), at a measurement temperature of 20°C, bromonaphthalene was used as a contact liquid, and the 589nm (D line) was measured. Refractive index nD.

[phase difference]

Ro(550) and Rth(589) of the film were measured at a measurement temperature of 20° C. using a retardation measuring device (“RETS-100” manufactured by Otsuka Electronics Co., Ltd.). Retardation is a value converted to a film thickness of 50 μm. this In addition, Ro(550) is the in-plane retardation at a wavelength of 550nm, and Rth(589) is the retardation in the thickness direction at a wavelength of 589nm.

[ooze]

Regarding the examples in which the ultraviolet absorber was added, the presence or absence of bleeding was visually observed on the surface of the obtained cured film.

(Example 1)

As shown in Table 1, 100 parts by mass of BPEF-9EOGA and 3 parts by mass of the photopolymerization initiator A were added, stirred and mixed at 70° C. for 1 hour, and a curable composition was obtained. Coat the support film with a roll coater, and then harden it by UV irradiation (500mJ/cm2) with an ultraviolet irradiation device ("ECS-151U" manufactured by iGrafx Co., Ltd.), and remove from the support film Peel off to make a cured film with a thickness of 100 μm. The pencil hardness, bending stability, bending durability, total light transmittance, partial light transmittance, yellowness, haze, refractive index, and retardation of the obtained cured film were measured. The measurement results are shown in Table 2.

(Example 2 to 5)

As shown in Table 1, a cured film was produced in the same manner as in Example 1, except that the UV absorber A and photopolymerization initiator B were added in the amounts shown in the table to the curable composition. . In addition, the film thickness of the cured film of Example 3 was 90 micrometers.

Various characteristics of the obtained cured film were measured in the same manner as in Example 1. The measurement results are shown in Table 2.

(Examples 6 to 9)

As shown in Table 1, a cured film was produced in the same manner as in Example 1 except that the ultraviolet absorber B and the photopolymerization initiator B were further added in the amounts shown in the table to the curable composition.

Various characteristics of the obtained cured film were measured in the same manner as in Example 1. The measurement results are shown in Table 2.

(Examples 10 to 11 and Comparative Examples 1 to 3)

As shown in Table 1, except that BPEF-5EOGA, BNEF-13EOGA, BPEF-9EOA, UV-3200B (ester) or epoxy ester 3000A is used instead of BPEF-9EOGA, the rest is made in the same way as in Example 1. Cured film . In addition, the film thickness of the cured film was 90 μm in Comparative Example 1, 200 μm in Comparative Example 2, and 120 μm in Comparative Example 3.

Various characteristics of the obtained cured film were measured in the same manner as in Example 1. The measurement results are shown in Table 2.

[Table 1]

[Table 2]

As can be clearly seen from the results in Table 2, in Examples, the surface hardness is high, the bending stability and durability are also excellent, and the optical characteristics are also excellent. In particular, Examples 1 to 4, 6 to 8, and 10 to 11 show high pencil hardness, and the results of comparing Example 1 with Examples 10 to 11 show that the number of moles increases with the addition of ethylene oxide However, there is an unexpected result that the pencil hardness decreases from the results of the examples of Patent Document 5. Furthermore, in the embodiment where the ultraviolet absorber is formulated, the ratio of the ultraviolet absorber is preferably 1 to 3 parts by mass relative to 100 parts by mass of BPEF-9EOGA, especially the ultraviolet blocking ability of 1 part by mass is improved, Moreover, various characteristics are also excellent.

[Industrial Utilization Possibility]

The optical film according to one of the preferred aspects of the present invention can be used as an optical film incorporated in a display portion of an image display device used for repeated bending. In particular, since it has both excellent surface hardness and bending resistance, it does not require hard coating, or can exhibit excellent surface hardness with only a very thin hard coating, and is suitable as a cover sheet for the aforementioned display portion. Furthermore, the aforementioned optical film system also has excellent optical properties and low retardation, so it is particularly suitable for foldable mobile information terminals as a cover sheet that also has excellent visibility of a display. The aforementioned mobile information terminal can be, for example, a mobile PC such as a smart phone, a notebook personal computer (PC), and a tablet PC, among which a foldable smart phone is preferred.

Claims (18)

An optical film that is incorporated into the display portion of an image display device that is repeatedly bent and used, and is cured from a curable composition containing epoxy (meth)acrylate represented by the following formula (1) who makes things,

In the formula, X represents a linking group selected from the group of the following formula (2),

In the formula, R ^3a and R ^3b are the same or different from each other and represent hydrogen atom, fluorine atom, chlorine atom, bromine atom, iodine atom, C _1-9 alkyl, C _1-5 alkoxy, C _4-12 cycloalkyl , C _6-12 aryl, C _2-5 alkenyl or C _7-17 aralkyl, R ^3a and R ^3b can also be bonded to form a carbocyclic or heterocyclic ring, p represents an integer greater than 1; Ring Z ^1a and Ring Z ^1b are the same or different from each other and represent an aromatic hydrocarbon ring, R ^1a and R ^1b are the same or different from each other and represent a substituent, m1 and m2 are the same or different from each other and represent an integer of 0 or more, A ^1a and A ^1b are the same or different from each other and represent a linear or branched chain alkylene group, n1 and n2 are the same or different from each other and represent an integer of 1 or more, R ^2a and R ^2b are the same or different from each other and represent a hydrogen atom or a methyl group. The optical film according to claim 1, wherein the epoxy (meth)acrylate is an epoxy (meth)acrylate represented by the following formula (1a),

In the formula, R represents a substituent, k represents an integer from 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 are the same as above. The optical film as claimed in item 1 or 2, wherein, in the aforementioned formula (1), the ring Z ^1a and the ring Z ^1b are the same or different from each other and represent a benzene ring or a naphthalene ring, and R ^1a and R ^1b are the same as each other or different and represent C _1-4 alkyl or C _6-10 aryl, n1+n2 represents an integer from 2 to 30. The optical film according to claim 1 or 2, wherein the epoxy (meth)acrylate is an epoxy (meth)acrylate represented by the following formula (1b),

In the formula, n1+n2 represents an integer of 3 to 20. The optical film as described in Claim 2, wherein the ratio of the (meth)epoxy acrylate represented by the aforementioned formula (1a) is greater than that of the (meth)epoxy acrylate represented by the aforementioned formula (1) 70 to 100 mol% in the system. The optical film according to claim 1 or 2, wherein the curable composition further contains an ultraviolet absorber. The optical film according to claim 1 or 2, wherein the cured product is a light cured product. The optical film according to claim 1 or 2, wherein the in-plane retardation Ro(550) is 50 nm or less, and the thickness direction retardation Rth(589) is 100 nm or less. The optical film according to claim 1 or 2, which has a total light transmittance of 85% or more and a spectral light transmittance of 8% or less at 380nm. The optical film according to claim 1 or 2, which is a cover sheet for a display. The optical film according to claim 1 or 2, which is a polarizing plate protective film. The optical film according to claim 1 or 2 has an average thickness of 20 to 200 μm. A polarizing plate, which is obtained by laminating the optical film and the polyvinyl alcohol polarizer described in any one of claims 1 to 12 with an adhesive. The polarizing plate according to claim 13, wherein the optical film contains an ultraviolet absorber, and the adhesive does not contain an ultraviolet absorber. An image display device comprising the optical film described in any one of Claims 1 to 12. The image display device according to claim 15 includes an organic EL display. The image display device as described in claim 15 or 16 is a foldable or rollable mobile information terminal. A method of using an optical film as a cover sheet, wherein the optical film described in any one of Claims 1 to 12 is placed on the surface of the display portion of an image display device that is repeatedly bent and used, and the optical film is used as a cover sheet use.

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