Photopolymerizable composition for inkjet printing, cured film thereof, and optical member and display device including the same

Abstract

The present invention relates to a photocurable composition that exhibits low refractive index after curing and that controls the decrease in transmittance and increase in haze, a cured film containing the cured product thereof, and an optical element and a display device that each contain the cured film.

Description

[Technical Field]

[0001] The present invention relates to a photopolymerizable composition for inkjet printing, a cured film thereof, and an optical member and a display device each including the same. [Background technology]

[0002] There is an increasing need to improve light efficiency in OLEDs (Organic Light Emitting Diodes) and image sensors. This technology is essential for improving OLED lifespan and increasing battery efficiency, and research and development into refractive index-controlling optical films has been actively conducted recently.

[0003] The theoretical upper and lower limits of the low refractive index range that can be adjusted with organic compounds are known to be around the early or mid-1.40 range. When hollow silica is mixed, the refractive index decreases, but compatibility with organic compounds can cause problems such as reduced transmittance, haze, and adhesion between the upper and lower layers. In addition, the viscosity of the composition increases, which can lead to problems such as poor inkjet processability, resulting in many technical limitations.

[0004] Due to the various problems of the conventional techniques, there is a continuous demand for the development of a technique that enables the formation of an optical film that exhibits low refractive index, while controlling the decrease in transmittance and the increase in haze, and exhibits excellent optical properties. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a photocurable composition that exhibits low refractive index and is capable of forming an optical film in which the decrease in transmittance and the increase in haze are controlled. The present invention also provides a cured film containing a cured product of the photocurable composition. The present invention also provides an optical member comprising the cured film. The present invention also provides a display device including the optical member.

[0006] However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0007] One embodiment of the present invention provides a photopolymerizable composition for inkjet printing, comprising: a first highly flexible monomer having a photocurable functional group and a viscosity of 10 cP or greater; a second highly flexible monomer having a photocurable functional group and a viscosity of less than 10 cP; a high-hardness monomer having a photocurable functional group; and one or more photoinitiators. According to an embodiment of the present invention, the first highly flexible monomer may include a compound represented by the following Formula 1: [Chemical formula 1] JPEG2026504361000001.jpg15170

[0008] In the above formula 1, A and A' are photocurable functional groups, B is a hydrocarbon containing one or more oxygen atoms, X is a direct bond or an allotrope having a structure of 3 or more carbon atoms, and m1 and n1 are each independently an integer of 0 or 1 to 2.

[0009] According to one embodiment of the present invention, the first highly flexible monomer has a liquid refractive index (nD 25 ) may be 1.47 or less, and the absolute viscosity measured at 25°C may be 10 cP or more and 65 cP or less.

[0010] According to one embodiment of the present invention, the first highly flexible monomer may include at least one of neopentyl glycol propoxylate di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and polypropylene glycol 400 di(meth)acrylate.

[0011] According to one embodiment of the present invention, based on 100 parts by weight of the monomer mixture including the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer, the content of the first highly flexible monomer may be 50 parts by weight or more and 89 parts by weight or less.

[0012] According to one embodiment of the present invention, the second highly flexible monomer has a liquid refractive index (nD 25 ) may be 1.45 or less, and the absolute viscosity measured at 25°C may be less than 10 cP.

[0013] According to one embodiment of the present invention, the second highly flexible monomer may include at least one of isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, and isostearyl (meth)acrylate.

[0014] According to one embodiment of the present invention, based on 100 parts by weight of the monomer mixture including the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer, the content of the second highly flexible monomer may be 1 part by weight or more and 20 parts by weight or less. According to one embodiment of the present invention, the high-hardness monomer may include a compound represented by the following Formula 2: [Chemical formula 2] JPEG2026504361000002.jpg19170

[0015] In the above formula 2, A and A' are photocurable functional groups, which may be the same or different from each other; Y is an aliphatic structure having 4 to 50 carbon atoms, which may or may not contain one or more oxygen atoms, and which includes a linear alkyl structure having at least 4 carbon atoms; and m2 and n2 are each independently an integer of 0 or 1. According to one embodiment of the present invention, the high hardness monomer has a liquid refractive index (nD 25 ) may be 1.49 or less.

[0016] According to one embodiment of the present invention, the high-hardness monomer may include at least one of 1,6-hexanediol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, and vinyloxyethoxyethyl (meth)acrylate.

[0017] According to one embodiment of the present invention, based on 100 parts by weight of the monomer mixture including the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer, the content of the high hardness monomer may be 10 parts by weight or more and 49 parts by weight or less.

[0018] According to one embodiment of the present invention, the content of the photopolymerization initiator may be 5 parts by weight or more and 20 parts by weight or less relative to 100 parts by weight of the monomer mixture including the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer.

[0019] According to one embodiment of the present invention, the first highly flexible monomer, the second highly flexible monomer, the high hardness monomer, and the photopolymerization initiator may have a purity of 95% or more as measured by gas phase chromatography. According to one embodiment of the present invention, the viscosity of the inkjet photopolymerizable composition may be 5 cP or more and 30 cP or less.

[0020] One embodiment of the present invention provides a cured film comprising a cured product of a photopolymerizable composition for inkjet printing, the cured product comprising: a first highly flexible monomer having a photocurable functional group and a viscosity of 10 cP or more; a second highly flexible monomer having a photocurable functional group and a viscosity of less than 10 cP; a high-hardness monomer having a photocurable functional group; and one or more photopolymerization initiators. The cured film has a haze of 0.5 or less when left for 500 hours at 85°C / 85% RH. The haze is defined as the degree of diffusion of light incident on a transparent film relative to the angle of incidence when the cured film is left in a thermo-hygrostat at 85°C for 500 hours and the haze value of the cured film is measured using a spectrophotometer, and is calculated according to the following equation 1: [Formula 1] JPEG2026504361000003.jpg21170 In the above formula 1, Ir is the transmittance of light transmitted at an incident angle of less than 2.5°, and Is is the transmittance of light transmitted at an incident angle of 2.5° or more. According to one embodiment of the present invention, the refractive index of the cured film may be 1.50 or less. According to one embodiment of the present invention, the modulus of the cured film may be 1 GPa or more. According to one embodiment of the present invention, the cured film may have an elongation of 5% or more.

[0021] According to one embodiment of the present invention, when a polarizer is attached to the cured film and left at 65°C / 90%RH for 500 hours or more, the change in the reflection color coordinate a* of the polarizer may be within ±0.5. One embodiment of the present invention provides an optical element comprising the cured film. An embodiment of the present invention provides a display device including the cured film as at least one of an optical film and a pattern film. [Effects of the Invention]

[0022] The photopolymerizable composition for inkjet printing according to one embodiment of the present invention can exhibit low refractive index, high transmittance, and low haze. The cured film according to one embodiment of the present invention exhibits low refractive index, high transmittance, and low haze. The optical member according to an embodiment of the present invention includes the cured film, thereby achieving excellent optical properties. The display device according to one embodiment of the present invention can exhibit excellent optical properties. The effects of the present invention are not limited to those described above, and effects not mentioned herein will be clearly understood by those skilled in the art from the present specification and the accompanying drawings. DETAILED DESCRIPTION OF THE INVENTION

[0023] Throughout this specification, when a part "comprises" a certain element, this does not mean that it excludes other elements, but that it may include other elements, unless otherwise specified.

[0024] Throughout this specification, when a member is said to be "on" another member, this does not only include when the member is in contact with the other member, but also when there is another member between the two members. Throughout this specification, the unit "parts by weight" can refer to the weight ratio between each component.

[0025] Throughout this specification, terms including ordinal numbers, such as "first" and "second," are used to distinguish one component from another, and are not limited by the ordinal number. For example, within the scope of the invention, a first component can also be designated as a second component, and similarly, a second component can be designated as a first component. Throughout this specification, "(meth)acrylate" is used generically to refer to acrylate and methacrylate. Throughout this specification, the viscosity of the compounds may be measured with a Brookfield viscometer at a temperature of 25°C. The present specification will be explained in more detail below.

[0026] One embodiment of the present invention provides a photopolymerizable composition for inkjet printing, comprising: a first highly flexible monomer having a photocurable functional group and a viscosity of 10 cP or greater; a second highly flexible monomer having a photocurable functional group and a viscosity of less than 10 cP; a high-hardness monomer having a photocurable functional group; and one or more photoinitiators.

[0027] A photopolymerizable composition for inkjet printing according to one embodiment of the present invention exhibits low refractive index, high transmittance, and low haze. Specifically, the photopolymerizable composition includes a first highly flexible monomer and a second highly flexible monomer, each having a viscosity within a specific range, thereby easily achieving low refractive index, high transmittance, and low haze after curing. Furthermore, the photopolymerizable composition exhibits excellent inkjet properties. Furthermore, the photopolymerizable composition exhibits improved modulus and elongation after curing, thereby improving mechanical properties, and effectively suppressing discoloration even under high temperature and high humidity conditions. According to an embodiment of the present invention, the first highly flexible monomer may include a compound represented by the following Formula 1: [Chemical formula 1] JPEG2026504361000004.jpg15170

[0028] In Formula 1, A and A' are photocurable functional groups, B is a hydrocarbon containing one or more oxygen atoms, X is a direct bond or an allotrope having a structure of 3 or more carbon atoms, and m1 and n1 are each independently an integer of 0 or 1 or 2. In Formula 1, A and A' are photocurable functional groups and may be (meth)acrylate groups. Specifically, A and A' may be acrylate groups. When A and A' are acrylate groups, a photopolymerizable composition can be provided that exhibits low refractive index, high transmittance, and low haze after curing. Furthermore, the photopolymerizable composition can exhibit excellent inkjet properties and, after curing, can suppress decreases in modulus and elongation, thereby improving mechanical properties.

[0029] In the above formula 1, B may be a straight or branched chain alkoxylene having 3 to 5 carbon atoms. Also, in the above formula 1, X may be a direct bond or a straight or branched chain alkylene having 1 to 5 carbon atoms.

[0030] By using the first highly flexible monomer including the compound represented by Chemical Formula 1, the photopolymerizable composition can more easily achieve low refractive index, high transmittance, and low haze after photocuring. As a result, the photopolymerizable composition can effectively provide a cured film with excellent optical properties. Furthermore, the photopolymerizable composition can have improved modulus and elongation after curing, thereby improving mechanical properties, and can effectively prevent discoloration even under high temperature and high humidity conditions. According to one embodiment of the present invention, the first highly flexible monomer may include a compound represented by the following Formula 1-1. [Chemical formula 1-1] JPEG2026504361000005.jpg34170

[0031] In the above Chemical Formula 1-1, R1 and R'1 are each independently hydrogen or a methyl group, R2 and R'2 are each independently a linear or branched alkoxylene having 3 to 5 carbon atoms, R3 is a direct bond or a linear or branched alkylene having 1 to 5 carbon atoms, m1 and n1 are each independently 0 or an integer of 1 to 2, and p is an integer of 0 or 1. Specifically, R1 and R'1 may be hydrogen. The compound may also be a linear or branched alkoxylene having 3 to 4 carbon atoms, or a linear or branched alkoxylene having 3 carbon atoms.

[0032] By using the first highly flexible monomer including the compound represented by Chemical Formula 1-1, the photopolymerizable composition can more easily achieve low refractive index, high transmittance, and low haze after photocuring. As a result, the photopolymerizable composition can effectively provide a cured film with excellent optical properties. Furthermore, the photopolymerizable composition can have properties that make it easy to apply to inkjet printing, and can improve mechanical properties by suppressing decreases in modulus and elongation after curing.

[0033] According to one embodiment of the present invention, the first highly flexible monomer has a liquid refractive index (nD 25) may be 1.47 or less, and the absolute viscosity measured at 25°C may be 10 cP or more and 65 cP or less. 25 ) may be 1.44 or more. A cured product of the photopolymerizable composition containing the first highly flexible monomer satisfying the liquid refractive index and absolute viscosity ranges described above may exhibit excellent low refractive index, high transmittance, and low haze. In addition, the photopolymerizable composition may exhibit excellent inkjet properties.

[0034] According to one embodiment of the present invention, the first highly flexible monomer may include at least one of neopentyl glycol propoxylate di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and polypropylene glycol 400 di(meth)acrylate. Specifically, the first highly flexible monomer may include at least one of neopentyl glycol propoxylate diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, and polypropylene glycol 400 diacrylate. When an acrylate compound of the above type is used as the first highly flexible monomer, the photopolymerizable composition may produce a cured film having a lower haze value, low refractive index, and high transmittance. Furthermore, the photopolymerizable composition may exhibit excellent inkjet characteristics and, after curing, may exhibit improved mechanical properties, such as improved modulus and elongation.

[0035] According to one embodiment of the present invention, based on 100 parts by weight of the monomer mixture including the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer, the content of the first highly flexible monomer may be from 50 to 89 parts by weight. Specifically, based on 100 parts by weight of the monomer mixture, the content of the first highly flexible monomer may be from 59 to 80 parts by weight, from 60 to 79 parts by weight, from 69 to 70 parts by weight, from 50 to 80 parts by weight, from 50 to 79 parts by weight, from 50 to 70 parts by weight, from 50 to 69 parts by weight, from 50 to 60 parts by weight, from 59 to 89 parts by weight, from 59 to 80 parts by weight, from 59 to 79 parts by weight, from 59 to 70 parts by weight, from 59 to 70 parts by weight, from 59 to 70 parts by weight, from 59 to 89 parts by weight, from 59 to 80 parts by weight, from 59 to 79 parts by weight, from 59 to 70 parts by weight, from 59 to 70 parts by weight, from 59 to 70 parts by weight, from 59 to 89 parts by weight, from 59 to 80 parts by weight, from 59 to 79 parts by weight, from 59 to 70 parts by weight, from 59 to 70 parts by weight, from 59 to 89 parts by weight, from 59 to 89 parts by weight, from 59 to 70 ... The amount may be 69 parts by weight or less, 59 parts by weight to 60 parts by weight, 60 parts by weight to 89 parts by weight, 60 parts by weight to 80 parts by weight, 60 parts by weight to 79 parts by weight, 60 parts by weight to 70 parts by weight, 60 parts by weight to 69 parts by weight, 69 parts by weight to 89 parts by weight, 69 parts by weight to 80 parts by weight, 69 parts by weight to 79 parts by weight, 70 parts by weight to 89 parts by weight, 70 parts by weight to 80 parts by weight, 70 parts by weight to 79 parts by weight, 79 parts by weight to 89 parts by weight, or 79 parts by weight to 80 parts by weight.

[0036] By adjusting the content of the first highly flexible monomer in the monomer mixture within the above range, the photopolymerizable composition can produce a cured film having a lower haze value, low refractive index, and high transmittance. In addition, the photopolymerizable composition can have physical properties that make it easy to apply to inkjet printing, and the cured product of the photopolymerizable composition can have improved mechanical properties such as increased modulus and elongation.

[0037] According to one embodiment of the present invention, the second highly flexible monomer may include a linear or branched alkyl group-containing (meth)acrylate having 10 to 20 carbon atoms. Specifically, the alkyl group contained in the alkyl group-containing (meth)acrylate may have 10 to 18 carbon atoms, 10 to 12 carbon atoms, 12 to 20 carbon atoms, 12 to 18 carbon atoms, or 18 to 20 carbon atoms. When the alkyl group-containing (meth)acrylate is used as the second highly flexible monomer, the photopolymerizable composition can more easily achieve low refractive index, high transmittance, and low haze after photocuring. In addition, the photopolymerizable composition has physical properties suitable for inkjet printing, and the cured product of the photopolymerizable composition can effectively prevent discoloration even under high temperature and high humidity conditions.

[0038] According to one embodiment of the present invention, the second highly flexible monomer has a liquid refractive index (nD 25 ) may be 1.45 or less, and the absolute viscosity measured at 25°C may be less than 10 cP. Specifically, the second highly flexible monomer may have a liquid refractive index (nD 25 ) may be 1.43 or more. In addition, the viscosity of the second highly flexible monomer may be 2 cP or more. A cured product of the photopolymerizable composition containing the first highly flexible monomer satisfying the liquid refractive index and absolute viscosity ranges described above may exhibit excellent low refractive index, high transmittance, and low haze. In addition, the photopolymerizable composition may exhibit excellent inkjet properties.

[0039] According to one embodiment of the present invention, the second highly flexible monomer may include at least one of isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, and isostearyl (meth)acrylate. Specifically, the second highly flexible monomer may include at least one of isodecyl acrylate, lauryl acrylate, stearyl acrylate, and isostearyl acrylate. When an acrylate compound of the above type is used as the second highly flexible monomer, the photopolymerizable composition may have a lower haze value, and a cured film having low refractive index and high transmittance may be produced.

[0040] According to one embodiment of the present invention, the content of the second highly flexible monomer may be 1 to 20 parts by weight based on 100 parts by weight of the monomer mixture including the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer. Specifically, the content of the second highly flexible monomer may be 1 to 10 parts by weight or 10 to 20 parts by weight based on 100 parts by weight of the monomer mixture. When the content of the second highly flexible monomer in the monomer mixture is within the above-mentioned range, the cured product of the photopolymerizable composition may exhibit excellent low refractive index, high transmittance, and low haze. The cured product of the photopolymerizable composition may have improved mechanical properties due to increased modulus and elongation, and may effectively suppress discoloration even under high temperature and high humidity conditions. According to one embodiment of the present invention, the high-hardness monomer may include a compound represented by the following Formula 2: [Chemical formula 2] JPEG2026504361000006.jpg19170

[0041] In Formula 2, A and A' are photocurable functional groups and may be the same or different; Y is an aliphatic structure having 4 to 50 carbon atoms, which may or may not contain one or more oxygen atoms, and includes a linear alkyl structure having at least 4 carbon atoms; and m2 and n2 are each independently an integer of 0 or 1. In Formula 2, A and A' are photocurable functional groups and may be (meth)acrylate groups. Specifically, A and A' may be acrylate groups. When A and A' are acrylate groups, a photopolymerizable composition can be provided that exhibits low refractive index, high transmittance, and low haze after curing. In Formula 2, Y may be a linear or branched alkylene having 4 to 50 carbon atoms, a linear or branched alkylene having 4 to 50 carbon atoms and containing a carbonyl group in the chain, or a hydrocarbon having 4 to 50 carbon atoms and containing one or more oxygen atoms in the chain and with or without an unsaturated bond.

[0042] By using the high-hardness monomer including the compound represented by Chemical Formula 2, the photopolymerizable composition can more easily achieve low refractive index, high transmittance, and low haze after photocuring. As a result, the photopolymerizable composition can effectively provide a cured film with excellent optical properties. Furthermore, the photopolymerizable composition can have properties that make it easy to apply to inkjet printing, and can have improved mechanical properties such as improved modulus and elongation after curing.

[0043] According to one embodiment of the present invention, the high-hardness monomer may include at least one of a compound represented by the following Formula 2-1 and a compound represented by the following Formula 2-2. [Chemical formula 2-1] JPEG2026504361000007.jpg34170

[0044] In the above formula 2-1, R 21 and R' 21 are each independently a hydrogen atom or a methyl group, and R 22 is a straight or branched chain alkylene having 4 to 50 carbon atoms, or -R23 -R 24 -R' 23 - may be. R 23 and R' 23 are each independently a straight or branched chain alkylene having 2 to 25 carbon atoms; R 24 may be a carbonyl group (—CO—). 21 and R' 21 R may be hydrogen. 22 R may be a straight or branched chain alkylene having 4 to 40 carbon atoms, a straight or branched chain alkylene having 4 to 30 carbon atoms, a straight or branched chain alkylene having 4 to 20 carbon atoms, a straight or branched chain alkylene having 4 to 10 carbon atoms, or a straight or branched chain alkylene having 4 to 6 carbon atoms. 23 and R' 23 may each independently be a straight or branched chain alkylene having 2 to 20 carbon atoms, a straight or branched chain alkylene having 2 to 15 carbon atoms, a straight or branched chain alkylene having 2 to 10 carbon atoms, or a straight or branched chain alkylene having 2 to 5 carbon atoms. [Chemical formula 2-2] JPEG2026504361000008.jpg47170

[0045] In the above formula 2-2, R 25 is hydrogen or a methyl group, and R 26 is a linear or branched alkoxylene having 1 to 3 carbon atoms, and q is an integer from 1 to 3. Specifically, R 25 R may be hydrogen. 26 may be a straight or branched chain alkoxylene having 1 or 2 carbon atoms, or a straight or branched chain alkoxylene having 2 or 3 carbon atoms. q may be an integer of 1 or 2, or an integer of 2 or 3.

[0046] By using the high-hardness monomer including at least one of the compound represented by Formula 2-1 and the compound represented by Formula 2-2, the photopolymerizable composition can more easily achieve low refractive index, high transmittance, and low haze after photocuring, thereby effectively providing a cured film with excellent optical properties.

[0047] According to one embodiment of the present invention, the high hardness monomer has a liquid refractive index (nD 25 ) may be 1.49 or less. Specifically, the liquid refractive index of the high-hardness monomer may be 1.44 or more. A cured product of the photopolymerizable composition containing the high-hardness monomer satisfying the liquid refractive index within the above range may exhibit excellent low refractive index, high transmittance, and low haze.

[0048] According to one embodiment of the present invention, the high-hardness monomer may include at least one of 1,6-hexanediol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, and vinyloxyethoxyethyl (meth)acrylate. Specifically, the high-hardness monomer may include at least one of 1,6-hexanediol diacrylate, hydroxypivalic acid neopentyl glycol diacrylate, and vinyloxyethoxyethyl acrylate. When an acrylate compound of the above type is used as the high-hardness monomer, the photopolymerizable composition may produce a cured film having a lower haze value, low refractive index, and high transmittance. Furthermore, the photopolymerizable composition may have physical properties suitable for inkjet printing, and the cured product of the photopolymerizable composition may exhibit improved mechanical properties, such as increased modulus and elongation.

[0049] According to one embodiment of the present invention, based on 100 parts by weight of the monomer mixture including the first high flexibility monomer, the second high flexibility monomer, and the high hardness monomer, the content of the high hardness monomer may be from 10 to 49 parts by weight. Specifically, based on 100 parts by weight of the monomer mixture, the content of the high hardness monomer may be from 10 to 40 parts by weight, from 10 to 30 parts by weight, from 10 to 2 parts by weight, from 20 to 49 parts by weight, from 20 to 40 parts by weight, from 20 to 30 parts by weight, from 30 to 49 parts by weight, from 20 to 40 parts by weight, or from 40 to 49 parts by weight.

[0050] By adjusting the content of the high-hardness monomer in the monomer mixture within the above-mentioned range, the photopolymerizable composition can realize a cured film having a lower haze value, low refractive index, and high transmittance. The cured product of the photopolymerizable composition can have improved mechanical properties due to increased modulus and elongation, and can effectively prevent discoloration even under high temperature and high humidity conditions.

[0051] According to one embodiment of the present invention, the photopolymerization initiator may include at least one of a phosphine oxide-based compound, an acetophenone-based compound, an acylphosphine oxide-based compound, (E)-2-(acetoximino)-1-(9,9-diethyl-9H-fluoren-2-yl)butanone, [1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazoyl-3-yl]-1-(O-acetyloxime), an oxime-based compound, and an oxime ester-based compound. Specifically, the photopolymerization initiator may include at least a phosphine oxide-based compound. When the above-mentioned photopolymerization initiator is used, stable photocuring of the photopolymerizable composition can be induced, thereby improving the optical properties of the cured product of the photopolymerizable composition. Examples of the photopolymerization initiator that can be used include Irgacure 819, a phosphine oxide compound, Irgacure 369 and Irgacure 907, which are acetophenone compounds, Darocure TPO, an acylphosphine oxide compound, OXE-01, which is an oxime compound, and OXE-04, which is an oxime ester compound.

[0052] According to one embodiment of the present invention, the content of the photopolymerization initiator may be 5 to 15 parts by weight, 5 to 10 parts by weight, 10 to 20 parts by weight, 10 to 15 parts by weight, or 15 to 20 parts by weight, relative to 100 parts by weight of the monomer mixture including the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer. By adjusting the content of the photopolymerization initiator within the above range, the polymerization reaction of the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer contained in the photopolymerizable composition can be carried out effectively and stably.

[0053] According to one embodiment of the present invention, the photopolymerization initiator may include one or more photopolymerization initiators. Specifically, the photopolymerization initiator may include a first photopolymerization initiator and a second photopolymerization initiator. The photopolymerization initiator may include a phosphine oxide-based compound. The second photopolymerization initiator may include at least one of an acetophenone-based compound, an acylphosphine oxide-based compound, (E)-2-(acetoximino)-1-(9,9-diethyl-9H-fluoren-2-yl)butanone, [1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazoyl-3-yl]-1-(O-acetyloxime), an oxime-based compound, and an oxime ester-based compound. In this case, the weight ratio of the first photopolymerization initiator to the second photopolymerization initiator may be 6:4 to 8:2. Using a mixture of the first photopolymerization initiator and the second photopolymerization initiator can induce stable photocuring of the photopolymerizable composition.

[0054] According to one embodiment of the present invention, the first highly flexible monomer, the second highly flexible monomer, the high hardness monomer, and the photopolymerization initiator may have a purity of 95% or more as measured by gas phase chromatography. By using the first highly flexible monomer, the second highly flexible monomer, the high hardness monomer, and the photopolymerization initiator having a purity of 95% or more, the photopolymerizable composition can effectively provide a cured film with excellent optical properties.

[0055] According to one embodiment of the present invention, the viscosity of the photopolymerizable composition for inkjet printing may be 5 cP or more and 30 cP or less. The viscosity of the photopolymerizable composition may be measured at 25°C. The photopolymerizable composition having a viscosity within the above range may be easily used for inkjet printing.

[0056] One embodiment of the present invention provides a cured film comprising a cured product of a photopolymerizable composition for inkjet printing, the cured product comprising: a first highly flexible monomer having a photocurable functional group and a viscosity of 10 cP or more; a second highly flexible monomer having a photocurable functional group and a viscosity of less than 10 cP; a high-hardness monomer having a photocurable functional group; and one or more photopolymerization initiators. The cured film has a haze of 0.5 or less when left for 500 hours at 85°C / 85% RH. The haze is defined as the degree of diffusion of light incident on a transparent film relative to the angle of incidence when the cured film is left in a thermo-hygrostat at 85°C for 500 hours and the haze value of the cured film is measured using a spectrophotometer, and is calculated according to the following equation 1: [Formula 1] JPEG2026504361000009.jpg21170

[0057] In Equation 1, Ir is the transmittance of light transmitted at an incident angle of less than 2.5°, and Is is the transmittance of light transmitted at an incident angle of 2.5° or more. Here, Ir may represent parallel transmittance, and Is may represent diffuse transmittance.

[0058] The cured film according to one embodiment of the present invention exhibits low refractive index, high transmittance, and low haze. In addition, the modulus and elongation are increased, resulting in excellent mechanical properties, and discoloration is effectively prevented even under high temperature and high humidity conditions.

[0059] The cured film according to an embodiment of the present invention may include a cured product of the photopolymerizable composition according to the above-described embodiment. In addition, the first highly flexible monomer, the second highly flexible monomer, the high hardness monomer, and the photopolymerization initiator in the cured film according to this embodiment may be the same as the first highly flexible monomer, the second highly flexible monomer, the high hardness monomer, and the photopolymerization initiator in the photopolymerizable composition according to the above-described embodiment.

[0060] According to one embodiment of the present invention, the cured film may have a refractive index of 1.50 or less. Specifically, the cured film may have a refractive index of 1.50 or less measured at an average wavelength of 555 to 575 nm. Meanwhile, the cured film may have a refractive index of 1.485 or more. The cured film has a refractive index of 1.5 or less, exhibiting low refractive properties and enabling the realization of optical devices and display devices with excellent optical properties.

[0061] According to one embodiment of the present invention, the modulus of the cured film may be 1 GPa or more. Alternatively, the modulus of the cured film may be 1.2 GPa or less. The cured film having a modulus value satisfying the above range may have excellent mechanical properties and may be easily applied to display devices.

[0062] According to one embodiment of the present invention, the cured film may have an elongation of 5% or more. Alternatively, the cured film may have an elongation of 8% or less. The cured film having an elongation value within the above range has excellent mechanical properties and may be easily applied to display devices.

[0063] According to one embodiment of the present invention, when a polarizer is attached to the cured film and left at 65°C / 90%RH for 500 hours or more, the change in the reflective color coordinate a* of the polarizer may be within ±0.5. That is, the cured film may exhibit excellent discoloration safety even under high temperature and high humidity conditions. One embodiment of the present invention provides an optical element comprising the cured film.

[0064] The optical member according to an embodiment of the present invention may include the cured film, thereby achieving excellent optical properties and effectively preventing discoloration of the optical member even under high temperature and high humidity conditions, thereby providing excellent safety.

[0065] According to one embodiment of the present invention, the optical member may include a substrate; and the cured film provided on the substrate. The cured film may be formed by applying the photopolymerizable composition to the substrate using an inkjet process and then photo-curing the composition. In this case, the substrate may be a well-known substrate such as bare glass.

[0066] The optical member may also be manufactured by applying the photopolymerizable composition to the substrate using a Mayer bar, coating applicator, or inkjet equipment, and then photocuring the composition by exposing the composition to light using, for example, an LED lamp or a metal halide lamp in an air atmosphere. The photopolymerizable composition may be applied in the form of a single layer and then photocured to form an optical member in the form of a general optical film. However, if necessary, the composition may be applied in a pattern using inkjet equipment and then photocured. In this case, the optical member may be in the form of a patterned film, in which a cured film patterned into a polyhedron, such as a prism structure, is formed on the substrate. An embodiment of the present invention provides a display device including the cured film as at least one of an optical film and a pattern film. The display device according to one embodiment of the present invention can exhibit excellent optical properties.

[0067] The optical member such as the optical film or pattern film may have a general thickness depending on the type and structure of the display device to which it is applied, for example, within a range of 0.01 μm to 1000 μm.

[0068] The structure of a display device to which an optical member such as an optical film or a pattern film is applied may be a conventional structure well known in the art, except that the cured film is applied to the optical member, and therefore, further description thereof will be omitted.

[0069] Hereinafter, the present invention will be described in detail with reference to examples. However, the examples of the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the examples described below. The examples in this specification are provided to more completely explain the present invention to those skilled in the art. First highly flexible monomer As the first highly flexible monomer, the following compound was prepared.

[0070] [Table 1] Second highly flexible monomer As the second highly flexible monomer, the following compound was prepared.

[0071] [Table 2] High hardness monomer As the high-hardness monomer, the following compound was prepared.

[0072] [Table 3] Photoinitiator The following compounds were prepared as photoinitiators.

[0073] [Table 4] Example Example 1 Preparation of photocurable composition

[0074] Neopentyl glycol propoxylate diacrylate was prepared as the first highly flexible monomer, isodecyl acrylate as the second highly flexible monomer, 1,6-hexanediol diacrylate as the high hardness monomer, and Irgacure 819 as the photoinitiator.

[0075] The first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer were then mixed to prepare a monomer mixture, which was then mixed with a photoinitiator to prepare a photocurable composition.

[0076] In this case, based on 100 parts by weight of the monomer mixture, the content of the first highly flexible monomer was 89 parts by weight, the content of the second highly flexible monomer was 1 part by weight, and the content of the high hardness monomer was 10 parts by weight. In addition, the content of the photoinitiator was 5 parts by weight per 100 parts by weight of the monomer mixture. Production of cured films

[0077] The inkjet photopolymerizable composition prepared above was coated on a bare glass substrate using an inkjet device (UniJet, OmniJet) to form a single layer with a thickness of 10 μm.

[0078] Then, using a 385nm LED curing machine, 2.2J / cm 2 A single film was irradiated with UV light to prepare a cured film (thickness: 10 μm) containing the cured product of the photopolymerizable composition for inkjet printing. Meanwhile, for refractive index measurement, a cured film with a thickness of 2 μm prepared by spin coating was used. Examples 2 to 20

[0079] A photocurable composition and a cured film were prepared in the same manner as in Example 1, except that the type and content of the first highly flexible monomer, the type and content of the second highly flexible monomer, the type and content of the high hardness monomer, and the content of the photoinitiator were adjusted as shown in Table 5 below.

[0080] [Table 5]

[0081] In Table 5, the contents (parts by weight) of the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer are based on 100 parts by weight of the monomer mixture, and the contents (parts by weight) of the photoinitiator are based on 100 parts by weight of the monomer mixture. Examples 21 to 36

[0082] A photocurable composition and a cured film were prepared in the same manner as in Example 1, except that the type and content of the first highly flexible monomer, the type and content of the second highly flexible monomer, the type and content of the high hardness monomer, and the content of the photoinitiator were adjusted as shown in Table 6 below.

[0083] [Table 6]

[0084] In Table 6, the contents (parts by weight) of the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer are based on 100 parts by weight of the monomer mixture, and the contents (parts by weight) of the photoinitiator are based on 100 parts by weight of the monomer mixture. Examples 37 to 48

[0085] A photocurable composition and a cured film were prepared in the same manner as in Example 1, except that the type and content of the first highly flexible monomer, the type and content of the second highly flexible monomer, the type and content of the high hardness monomer, and the content of the photoinitiator were adjusted as shown in Table 7 below.

[0086] [Table 7]

[0087] In Table 7, the contents (parts by weight) of the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer are based on 100 parts by weight of the monomer mixture, and the contents (parts by weight) of the photoinitiator are based on 100 parts by weight of the monomer mixture. Examples 49 to 63

[0088] A photocurable composition and a cured film were prepared in the same manner as in Example 1, except that the type and content of the first highly flexible monomer, the type and content of the second highly flexible monomer, the type and content of the high hardness monomer, and the type and content of the photoinitiator were adjusted as shown in Table 8 below.

[0089] [Table 8]

[0090] In Table 8, the contents (parts by weight) of the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer are based on 100 parts by weight of the monomer mixture, and the contents (parts by weight) of the photoinitiator are based on 100 parts by weight of the monomer mixture. Comparative Example Comparative Examples 1 to 10

[0091] A photocurable composition and a cured film were prepared in the same manner as in Example 1, except that the type and content of the first highly flexible monomer, the type and content of the second highly flexible monomer, the type and content of the high hardness monomer, and the content of the photoinitiator were adjusted as shown in Table 9 below.

[0092] [Table 9]

[0093] In Table 9, the contents (parts by weight) of the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer are based on 100 parts by weight of the monomer mixture, and the contents (parts by weight) of the photoinitiator are based on 100 parts by weight of the monomer mixture. Comparative Examples 11 to 24

[0094] Photocurable compositions and cured films were prepared in the same manner as in Example 1, except that the type and content of the first highly flexible monomer, the type and content of the second highly flexible monomer, the type and content of the high hardness monomer, and the content of the photoinitiator were adjusted as shown in Table 10 below.

[0095] [Table 10]

[0096] In Table 10, the contents (parts by weight) of the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer are based on 100 parts by weight of the monomer mixture, and the contents (parts by weight) of the photoinitiator are based on 100 parts by weight of the monomer mixture. Comparative Examples 25 to 32

[0097] Photocurable compositions and cured films were prepared in the same manner as in Example 1, except that the type and content of the first highly flexible monomer, the type and content of the second highly flexible monomer, the type and content of the high hardness monomer, and the content of the photoinitiator were adjusted as shown in Table 11 below.

[0098] [Table 11]

[0099] In Table 11, the contents (parts by weight) of the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer are based on 100 parts by weight of the monomer mixture, and the contents (parts by weight) of the photoinitiator are based on 100 parts by weight of the monomer mixture. Comparative Examples 33 to 40

[0100] A photocurable composition and a cured film were prepared in the same manner as in Example 1, except that the type and content of the first highly flexible monomer, the type and content of the second highly flexible monomer, the type and content of the high hardness monomer, and the content of the photoinitiator were adjusted as shown in Table 12 below.

[0101] [Table 12]

[0102] In Table 12, the contents (parts by weight) of the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer are based on 100 parts by weight of the monomer mixture, and the contents (parts by weight) of the photoinitiator are based on 100 parts by weight of the monomer mixture. Comparative Examples 41 to 64

[0103] Photocurable compositions and cured films were prepared in the same manner as in Example 1, except that the type and content of the first highly flexible monomer, the type and content of the high hardness monomer, and the content of the photoinitiator were adjusted as shown in Table 13. Comparative Examples 41 to 64 did not contain the second highly flexible monomer.

[0104] [Table 13]

[0105] In Table 13, the contents (parts by weight) of the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer are based on 100 parts by weight of the monomer mixture, and the contents (parts by weight) of the photoinitiator are based on 100 parts by weight of the monomer mixture. Comparative Examples 65 to 80

[0106] A photocurable composition and a cured film were prepared in the same manner as in Example 1, except that the type and content of the first highly flexible monomer, the type and content of the high hardness monomer, and the content of the photoinitiator were adjusted as shown in Table 14 below.

[0107] [Table 14]

[0108] In Table 14, the contents (parts by weight) of the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer are based on 100 parts by weight of the monomer mixture, and the contents (parts by weight) of the photoinitiator are based on 100 parts by weight of the monomer mixture. Experimental example

[0109] The following experiments were carried out on the photocurable compositions and cured films prepared in Examples 1 to 63 and the photocurable compositions and cured films prepared in Comparative Examples 1 to 80, and the results are shown in Tables 15 to 34 below. 1) Haze A 10 μm thick cured film was left at 85° C. / 85% RH for 500 hours, and then the haze was measured using a COH400 made by NIPPON DENSHOKU. judgement ◎: Haze measurement value is less than 0.5 ○: Haze measurement value is 0.5 to 1.0 or less X: Haze measurement value exceeds 1.0 2) The sensitivity

[0110] Using an FT-IR spectrophotometer, the absorbance of the cured film before and after exposure was measured and compared. -1 C=O peak and 780-840 cm -1 The conversion rate was determined by integrating the C=C peak, and the sensitivity means the exposure amount at which the conversion rate is saturated at 80% or more. judgement ○: Sensitivity value is 3.0 J or less X: Sensitivity value exceeds 3.0J 3) Refractive index The refractive index (average of 555 to 575 nm) of the cured film having a thickness of 2 μm formed on the bare glass substrate was measured using an ellipsometer. judgement ◎: When the measured refractive index of the coating film is less than 1.50 X: The measured refractive index of the coating film is 1.50 or more. 4) Transparency

[0111] The average transmittance of the 10 μm thick cured film formed on the bare glass substrate was measured at 380 to 780 nm using a UV-VIS spectrophotometer (Cary4000, Agilent). judgement ○: Average transmittance is 98% or more X: Average transmittance is less than 98% 5) Viscosity (absolute viscosity)

[0112] The viscosity of each of the inkjet photopolymerizable compositions or monomers in the comparative examples and examples was measured at 25° C. using a viscometer (trade name: Brookfield viscometer). judgement ○: Viscosity value is between 5 and 30 cP X: Viscosity value outside the above range 6) Inkjet characteristics We checked whether a surface was formed by changing the nozzle temperature of the inkjet equipment. judgement Surface formation at nozzle temperatures below 25 to 35°C: Surface formed at nozzle temperature of 35 to 50°C: ○ No surface formed at nozzle temperature of 25 to 50°C: X 7) Modulus

[0113] The modulus was measured by pressing a 10 μm thick cured film coated on bare glass with a nanoindenter (HM500, Helmut Fischer) Vickers Tip to a depth of 10%. O: Modulus 1.0 GPa to 1.5 GPa X: Modulus less than 1.0 GPa or more than 1.5 GPa 8)Flexibility

[0114] The flexibility was evaluated by peeling the 10 μm cured film from bare glass to prepare a dog bone specimen, and measuring the tensile strain using a UTM (Instron). judgement ◎: Tensile strain of 5% or more O: Tensile strain less than 3% or 5% X: Tensile strain less than 3% 9) Discoloration of polarizing plates due to high temperature / humidity

[0115] A polarizing plate was attached to a 10 μm thick cured film formed on a bare glass substrate, and after leaving it at 65°C / 90% RH for 500 hours, the change in the a* reflection color coordinate of the polarizing plate was measured using a spectrophotometer (Konica Minolta CM-5). judgement ◎: Less than Δa*±0.5 O: Δa* ±0.5 or more ±1.0 or less X: Δa* ±1.0 or more

[0116] [Table 15]

[0117] [Table 16]

[0118] Referring to Tables 15 and 16 above, it was confirmed that the photopolymerizable compositions prepared in Examples 1 to 20 of the present invention were capable of producing cured films exhibiting low haze, sensitivity, refractive index, and transmittance, thereby demonstrating excellent inkjet properties. In addition, it was confirmed that the cured films of the photopolymerizable compositions prepared in Examples 1 to 20 had excellent modulus and flexibility, and excellent discoloration stability under high temperature and high humidity conditions.

[0119] [Table 17]

[0120] [Table 18]

[0121] Referring to Tables 17 and 18, the photopolymerizable compositions prepared in Examples 21 to 36 of the present invention were able to produce cured films exhibiting low haze, sensitivity, refractive index, and transmittance, demonstrating excellent inkjet properties. In addition, the cured films of the photopolymerizable compositions prepared in Examples 21 to 36 were found to have excellent modulus and flexibility, and to have excellent discoloration resistance under high temperature and humidity conditions.

[0122] [Table 19]

[0123] [Table 20]

[0124] Referring to Tables 19 and 20 above, it was confirmed that the photopolymerizable compositions prepared in Examples 37 to 48 of the present invention were capable of producing cured films exhibiting low haze, sensitivity, refractive index, and transmittance, thereby demonstrating excellent inkjet properties. In addition, it was confirmed that the cured films of the photopolymerizable compositions prepared in Examples 37 to 48 had excellent modulus and flexibility, and were stable against discoloration under high temperature and humidity conditions.

[0125] [Table 21]

[0126] [Table 22]

[0127] Referring to Tables 21 and 22 above, it was confirmed that the photopolymerizable compositions prepared in Examples 49 to 63 of the present invention were capable of producing cured films exhibiting low haze, sensitivity, refractive index, and transmittance, thereby demonstrating excellent inkjet properties. In addition, it was confirmed that the cured films of the photopolymerizable compositions prepared in Examples 49 to 63 had excellent modulus and flexibility, and excellent discoloration resistance under high temperature and high humidity conditions.

[0128] [Table 23]

[0129] [Table 24]

[0130] Referring to Tables 23 and 24, it was found that the haze and flexibility properties were very poor in the photopolymerizable compositions prepared in Comparative Examples 1 to 10. That is, it was found that Comparative Examples 1 to 10, which do not use the first highly flexible monomer according to an embodiment of the present invention, were unable to prepare cured films with excellent haze and flexibility properties.

[0131] [Table 25]

[0132] [Table 26]

[0133] Referring to Tables 25 and 26, it was found that the haze and flexibility properties were very poor in the photopolymerizable compositions prepared in Comparative Examples 11 to 24. That is, it was found that Comparative Examples 11 to 24, which do not use the first highly flexible monomer according to an embodiment of the present invention, were unable to prepare cured films with excellent haze and flexibility properties.

[0134] [Table 27]

[0135] [Table 28]

[0136] Referring to Tables 27 and 28, it was found that the haze properties were very poor in the photopolymerizable compositions prepared in Comparative Examples 25 to 32. That is, it was found that cured films with excellent haze properties could not be prepared in Comparative Examples 25 to 32, which do not use the second highly flexible monomer according to an embodiment of the present invention.

[0137] [Table 29]

[0138] [Table 30]

[0139] Referring to Tables 29 and 30, it was confirmed that the photopolymerizable compositions prepared in Comparative Examples 33 to 40 were unable to achieve both a low haze value and a low refractive index. In particular, it was found that the compositions of Comparative Examples 33 to 40, which do not use the second highly flexible monomer according to an embodiment of the present invention, were unable to produce cured films exhibiting both a low haze value and a low refractive index.

[0140] [Table 31]

[0141] [Table 32]

[0142] Referring to Tables 31 and 32, it was confirmed that the photopolymerizable compositions prepared in Comparative Examples 41 to 64 had very poor flexibility. In addition, it was confirmed that the photopolymerizable compositions prepared in Comparative Examples 53 to 64 also had very poor modulus. In other words, it was found that the photopolymerizable compositions prepared in Comparative Examples 41 to 64, which do not contain the second highly flexible monomer according to one embodiment of the present invention, were unable to prepare cured films with excellent flexibility.

[0143] [Table 33]

[0144] [Table 34]

[0145] Referring to Tables 33 and 34, it was confirmed that the photopolymerizable compositions prepared in Comparative Examples 65 to 80 either had very poor sensitivity characteristics or the photopolymerization initiator precipitated in the cured film. On the other hand, it was confirmed that the refractive index and discoloration characteristics were very poor in Comparative Example 66. In other words, it was confirmed that the cured films intended to embody the present invention could not be prepared in Comparative Examples 65 to 80, where the photopolymerization initiator content was outside the aforementioned range.

[0146] Therefore, it can be seen that the photopolymerizable composition according to one embodiment of the present invention can realize a cured film having excellent inkjet properties and exhibiting low refractive index, high transmittance, and low haze after curing. Furthermore, it can be seen that the cured film including the cured product of the photopolymerizable composition has improved mechanical properties such as improved modulus and elongation, and is effectively prevented from discoloring even under high temperature and high humidity conditions.

Claims

1. a first highly flexible monomer having a photocurable functional group and a viscosity of 10 cP or more; a second highly flexible monomer comprising a photocurable functional group and having a viscosity of less than 10 cP; a high hardness monomer containing a photocurable functional group; and An inkjet photopolymerizable composition comprising: one or more photoinitiators.

2. The photopolymerizable composition for inkjet printing according to claim 1 , wherein the first highly flexible monomer comprises a compound represented by the following Chemical Formula 1: [Chemical formula 1] In the above formula 1, A and A' are photocurable functional groups, B is a hydrocarbon containing one or more oxygen atoms, X is a direct bond or an allotrope having a structure of 3 or more carbon atoms, and m1 and n1 are each independently an integer of 0 or 1 to 2.

3. The first highly flexible monomer has a liquid refractive index (nD ２５ 2. The photopolymerizable composition for ink jet recording according to claim 1, wherein the absolute viscosity measured at 25°C is 10 cP or more and 65 cP or less.

4. 2. The inkjet photopolymerizable composition of claim 1, wherein the first highly flexible monomer comprises at least one of neopentyl glycol propoxylate di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, and polypropylene glycol 400 di(meth)acrylate.

5. 2. The photopolymerizable composition for inkjet according to claim 1, wherein the content of the first highly flexible monomer is 50 parts by weight or more and 89 parts by weight or less, based on 100 parts by weight of a monomer mixture including the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer.

6. The second highly flexible monomer has a liquid refractive index (nD ２５ 2. The inkjet photopolymerizable composition according to claim 1, wherein the absolute viscosity measured at 25°C is less than 10 cP and the absolute viscosity is 1.45 or less.

7. 2. The inkjet photopolymerizable composition of claim 1, wherein the second highly flexible monomer comprises at least one of isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, and isostearyl (meth)acrylate.

8. 2. The photopolymerizable composition for inkjet according to claim 1, wherein the content of the second highly flexible monomer is 1 part by weight or more and 20 parts by weight or less, based on 100 parts by weight of a monomer mixture including the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer.

9. The photopolymerizable composition for inkjet printing according to claim 1 , wherein the high-hardness monomer comprises a compound represented by the following Chemical Formula 2: [Chemical formula 2] In Formula 2, A and A' are photocurable functional groups and may be the same or different; Y is an aliphatic structure having 4 to 50 carbon atoms, which may or may not contain one or more oxygen atoms, and includes a linear alkyl structure having at least 4 carbon atoms; and m2 and n2 are each independently an integer of 0 or 1.

10. The high-hardness monomer has a liquid refractive index (nD ２５ 2. The ink jet photopolymerizable composition of claim 1, wherein the ρ is 1.49 or less.

11. 2. The photopolymerizable composition for inkjet printing according to claim 1, wherein the high-hardness monomer comprises at least one of 1,6-hexanediol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, and vinyloxyethoxyethyl (meth)acrylate.

12. 2. The photopolymerizable composition for inkjet according to claim 1, wherein the content of the high hardness monomer is 10 parts by weight or more and 49 parts by weight or less, based on 100 parts by weight of a monomer mixture including the first high flexibility monomer, the second high flexibility monomer, and the high hardness monomer.

13. 2. The photopolymerizable composition for inkjet according to claim 1, wherein the content of the photopolymerization initiator is 5 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of a monomer mixture including the first highly flexible monomer, the second highly flexible monomer, and the high hardness monomer.

14. 2. The photopolymerizable composition for inkjet according to claim 1, wherein the first highly flexible monomer, the second highly flexible monomer, the high hardness monomer, and the photopolymerization initiator have a purity of 95% or more as measured by gas phase chromatography.

15. The photopolymerizable composition for inkjet according to claim 1 , wherein the viscosity of the photopolymerizable composition for inkjet is 5 cP or more and 30 cP or less.

16. a first highly flexible monomer having a photocurable functional group and a viscosity of 10 cP or more; a second highly flexible monomer comprising a photocurable functional group and having a viscosity of less than 10 cP; a high hardness monomer containing a photocurable functional group; and A cured film comprising a cured product of a photopolymerizable composition for inkjet printing, the photopolymerizable composition comprising one or more photopolymerization initiators, When left for 500 hours under conditions of 85°C / 85%RH, the haze is 0.5 or less, The haze is defined as the degree of diffusion of light incident on a transparent film relative to the incident angle when the cured film is left in a thermo-hygrostat at 85°C for 500 hours and then the haze value of the cured film is measured using a spectrophotometer, and is calculated according to the following equation 1: [Formula 1] In the above formula 1, Ir is the transmittance of light transmitted at an incident angle of less than 2.5°, and Is is the transmittance of light transmitted at an incident angle of 2.5° or more.

17. The cured film according to claim 16, wherein the refractive index of the cured film is 1.50 or less.

18. 17. The cured film of claim 16, wherein the modulus of the cured film is 1 GPa or greater.

19. The cured film according to claim 16, wherein the cured film has an elongation of 5% or more.

20. The cured film according to claim 16, wherein when a polarizing plate is attached to the cured film and the polarizing plate is left standing under conditions of 65°C / 90% RH for 500 hours or more, the change in the reflection color coordinate a* of the polarizing plate is ±0.5 or less.

21. An optical component comprising the cured film according to claim 16.

22. A display device comprising the cured film according to claim 16 as at least one of an optical film and a pattern film.

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