Hard coat layer-forming active energy ray-curable composition, hard coat film using the same, and laminate of the hard coat film

Abstract

The present invention provides a kind of hard coating formation with active energy ray hardenable composition, the hard coating film using the composition and the laminate of the hard coating film, wherein the damage in display production process is inhibited, the curl production caused by hardening shrinkage, and the elution of ultraviolet cut agent in the saponification process of TAC film.The problem can be solved by hard coating formation with active energy ray hardenable composition, which is a composition for forming a hard coating on triacetyl cellulose film, containing: active energy ray hardenable component (A) comprising a specific (meth) acrylate, ultraviolet cut agent (B), photopolymerization initiator (C) and specific solvent (D).

Description

Technical Field

[0001] This invention relates to an active energy line-curable composition for hard coating formation, a hard coating film using the composition, and a laminate of the hard coating film. More specifically, it relates to an active energy line-curable composition for hard coating formation, a hard coating film using the composition, and a laminate of the hard coating film, applicable to displays of TVs, notebook computers, mobile phones, smartphones, etc. Background Technology

[0002] In the application of displays for televisions (TV), laptops, mobile phones, smartphones, etc., in addition to the liquid crystal displays (LCDs) that were mostly used in the past, a wide variety of displays have been developed, and products that make effective use of various features have gradually developed in the market.

[0003] Organic electroluminescence (EL) displays have rapidly expanded into various applications such as TVs and smartphones. However, the light-emitting elements used in organic EL displays are not resistant to water vapor and impurity gases generated by the constituent materials. Therefore, as a countermeasure against degradation caused by water vapor, an inorganic compound barrier layer (inorganic layer) is set on the substrate, or as a countermeasure against impurity gases, the volatile components are reduced, thereby protecting the light-emitting elements.

[0004] Furthermore, external factors such as heat or ultraviolet radiation have a significant impact. In particular, the effects of ultraviolet radiation are not limited to the high-energy region at lower wavelengths; the degrading effects of ultraviolet radiation near the 400nm wavelength range, close to visible light, are also substantial. Therefore, considering outdoor use, a UV blocking function is required to protect the internal structure from ultraviolet radiation intruding from outside the display.

[0005] On the other hand, a polarizing plate is stacked in a typical organic EL display. The polarizing plate used in an organic EL display is called a circular polarizing plate, which is different from the one used in a liquid crystal display for light transmission control. Metal is used in the electrode section constituting the organic EL display, where incident light from the outside is scattered within the display. A circular polarizing plate is stacked to avoid the influence of the incident light from the outside.

[0006] Historically, polarizing plates have mostly used water-soluble polyvinyl alcohol (PVA) for ease of contact with liquid crystals, and are manufactured by dyeing with iodine and then stretching it into a film. PVA polarizing plates are hygroscopic, so a triacetyl cellulose (TAC) film with excellent non-flammability, appearance (transparency), and insulation is used as a protective film.

[0007] When bonding a polarizing plate made of PVA to a TAC film, a caustic alkali is used to saponify the surface of the TAC film, hydrolyzing some of the acetyl groups (-O=COCH groups) on the surface of the TAC film into hydrophilic groups, namely hydroxyl groups (-OH).

[0008] The saponification process for TAC film involves immersing the TAC film in an alkaline aqueous solution such as sodium hydroxide (NaOH) or potassium hydroxide (KOH). When TAC film is used for polarization in displays, it is often layered with other functional layers such as a hard coat (HC) layer, an anti-glare (AG) layer, an anti-reflective (AR) layer, and an anti-static (AS) layer on the opposite side of the polarizing plate.

[0009] The process of laminating these functional layers is usually carried out before the saponification treatment using caustic alkali to maintain the adhesion between the PVA polarizing plate and the TAC film.

[0010] Therefore, performing saponification with strong alkali after layering functional layers will damage the hard-won functional layers, resulting in a decrease in functionality.

[0011] Furthermore, devices including displays, especially mobile devices such as laptops, mobile phones, smartphones, tablets, and smartwatches, prioritize portability and are therefore pushing for lightweighting and miniaturization. Research is also underway to increase the multifunctionality and thin-film capabilities of functional layers in display structures. In thin-film research, progress is being made in reducing the thickness of substrate films, and thin films from 100 μm to below 50 μm are also being investigated.

[0012] If an active energy line curing composition is coated on a membrane, it will usually warp or curl due to curing shrinkage, and this tendency becomes more pronounced due to the thinning of the membrane substrate.

[0013] Since displays are composed of stacked functional layers, the curling of the substrate after the functional layers are formed will lead to a deterioration in workability and a reduction in yield in subsequent processes.

[0014] In Patent Documents 1 and 2, as a study on the multifunctionalization and thin-filmization of functional layers in a display structure, a transparent double-sided adhesive sheet is illustrated. This double-sided adhesive sheet is disposed between the viewing side of the polarizing plate layer and the display part of the organic EL display and is used to integrate the two components. It has at least one ultraviolet absorption layer and reduces the transmittance of light with a wavelength of 380nm.

[0015] However, when adding a UV blocker to the double-sided adhesive sheet, the amount added is naturally limited in terms of preventing leakage and improving adhesion. Therefore, due to the thin film of the component, it is not possible to fully block the UV rays incident on the display part, and it is not possible to prevent adverse effects on the display.

[0016] On the other hand, when the UV blocking functional layer is laminated on the opposite side of the TAC film that is tightly sealed to the PVA polarizing plate, the UV blocking agent may sometimes dissolve from the UV blocking functional layer due to the saponification treatment of the TAC film, resulting in an increase in UV transmittance and dissolution (contamination) of the UV blocking agent into the saponification treatment liquid.

[0017] As a countermeasure, Patent Document 3 illustrates a method of selectively saponifying only the side opposite to the TAC film with the UV-curing functional layer, but this method cannot eliminate the effect of saponification on the UV-blocking layer. Furthermore, increasing the crosslinking density of the functional layer can lead to problems such as curling due to curing shrinkage. While applying a protective film during the saponification process has been considered, it is believed that this would result in deterioration or increased costs due to the added steps. On the other hand, it is necessary to suppress the effect of the UV-blocking agent on UV curing, and further improvements are needed.

[0018] [Existing Technical Documents]

[0019] [Patent Literature]

[0020] [Patent Document 1] Japanese Patent Application Publication No. 2012-211305

[0021] [Patent Document 2] Japanese Patent Application Publication No. 2022-000694

[0022] [Patent Document 3] Japanese Patent Application Publication No. 2007-308670

[0023] [Patent Document 4] International Publication No. 2020 / 209264 Summary of the Invention

[0024] [The problem the invention aims to solve]

[0025] The present invention provides an active energy line curing composition for hard coating formation, a hard coating film using the composition, and a laminate of the hard coating film, wherein damage in the display manufacturing process, curling caused by curing shrinkage, and dissolution of ultraviolet blocking agents in the saponification process of TAC film are suppressed.

[0026] [Technical means to solve the problem]

[0027] The present invention addresses the aforementioned problem through repeated efforts and has found that the problem can be solved by using the active energy line hardening composition described below, thus completing the present invention.

[0028] This invention relates to an active energy line curing composition for forming a hard coating, which is a composition for forming a hard coating on a triacetyl cellulose membrane, comprising: an active energy line curing component (A), an ultraviolet blocking agent (B), a photopolymerization initiator (C), and a solvent (D). The active energy line curing component (A) comprises a polyfunctional urethane (meth)acrylate (a1) having 6 or more (meth)acryloyl groups and having a urate ring skeleton, a polyfunctional urethane (meth)acrylate (a2) having 4 or more and 15 or fewer (meth)acryloyl groups and having a weight average molecular weight of 500 to 15,000, and other polyfunctional (meth)acrylates (a3). The solvent (D) comprises a solvent (d1) satisfying the following formula (1) and a solvent (d2) other than solvent (d1).

[0029] Equation (1) [(X2) / (X1)] ≥ 0.25

[0030] (X1): Haze value of an 80 μm thick triacetylcellulose membrane without added solvent.

[0031] (X2): Haze value of an 80 μm thick triacetylcellulose membrane after solvent addition and drying.

[0032] In addition, the present invention relates to a hard coating film having a hard coating comprising an active energy line curing composition for forming the hard coating film on a triacetyl cellulose film.

[0033] In addition, the present invention relates to the hard coating film wherein the transmittance (ta) at a wavelength of 380 nm is less than 4% and the transmittance (tb) at a wavelength of 420 nm is more than 70%.

[0034] In addition, the present invention relates to the hard coating film, wherein the following formula (2) is satisfied.

[0035] Equation (2) (tc)-(ta)≦1%

[0036] (ta): Transmittance of the hard coating film at 380 nm without immersion in sodium hydroxide aqueous solution; (tc): Transmittance of the hard coating film at 380 nm after immersion in sodium hydroxide aqueous solution, washing, and drying.

[0037] In addition, the present invention relates to a laminate having the aforementioned hard coating film and circular polarizing functional layer laminated thereon.

[0038] [The effects of the invention]

[0039] The present invention provides an active energy line curing composition for hard coating formation, a hard coating film using the composition, and a laminate of the hard coating film, wherein damage in the display manufacturing process, curling caused by curing shrinkage, and dissolution of ultraviolet blocking agents in the saponification process of TAC film are suppressed. Attached Figure Description

[0040] Figure 1 This is a diagram of the stacked structure of an organic EL display (1).

[0041] Figure 2 This is a diagram of the stacked structure of an organic EL display (2).

[0042] [Explanation of Symbols]

[0043] 1: Transparent optical material layer

[0044] 2: Hard coating

[0045] 3: TAC

[0046] 4: Polarizing film (PVA)

[0047] 5: Phase difference layer

[0048] 6: Structures containing organic EL light-emitting layers

[0049] 7: Phase Difference (TAC)

[0050] 8: Circular polarizing functional layer Detailed Implementation

[0051] The present invention will now be described in detail. Furthermore, other embodiments are naturally included within the scope of the present invention as long as they conform to its spirit. Additionally, in this specification, the numerical range defined by "~" includes the range of values ​​before and after "~" as both the lower and upper limits.

[0052] First, let me explain the terminology used in this instruction manual.

[0053] In this specification, the terms “(meth)acrylate”, “(meth)acryloyl”, and “(meth)acrylate”, unless otherwise specified, represent “acrylic or methacrylate”, “acryloyl or methacryloyl”, and “acrylate or methacrylate”, respectively.

[0054] Additionally, the term "active energy line curing composition for hard coating formation" is sometimes used as "composition for hard coating formation," "polyfunctional urethane (meth)acrylate (a1) having 6 or more (meth)acryloyl groups and a urate ring skeleton" is used as "polyfunctional urethane (meth)acrylate (a1)," "polyfunctional urethane (meth)acrylate (a2) having 4 or more and 15 or fewer (meth)acryloyl groups and a weight average molecular weight of 500 to 15,000" (excluding (a1)) is used as "polyfunctional urethane (meth)acrylate (a2)," and "other polyfunctional (meth)acrylate (a3)" is used as "polyfunctional (meth)acrylate (a3)." Unless otherwise specified, each component appearing in this specification may be used independently, alone, or in combination of two or more.

[0055] "Active Energy Line Hardening Component (A)"

[0056] The active energy line hardening component (A) includes all of the following: polyfunctional urethane (meth)acrylates (a1) having 6 or more (meth)acryloyl groups and having a urate ring skeleton; polyfunctional urethane (meth)acrylates (excluding (a1)) having 4 or more and 15 or fewer (meth)acryloyl groups and having a weight average molecular weight of 500 to 15,000; and other polyfunctional (meth)acrylates (a3).

[0057] The term "polyfunctional urethane (meth)acrylate" refers to oligomers that have urethane bonds and two or more (meth)acrylate groups.

[0058] <Polyfunctional carbamate (meth)acrylate (a1)>

[0059] The polyfunctional urethane (meth)acrylate (a1) has six or more (meth)acryloyl groups and a urate ring backbone. The urate ring backbone is a trimer of isocyanate compounds with nitrogen atoms and has a six-membered ring structure. The presence of six or more (meth)acryloyl groups increases the crosslinking density, resulting in excellent hardness or scratch resistance of the hard coating film surface and inhibiting curling of the hard coating film. The detailed factors inhibiting curling are not yet clear, but it is believed that the ring structure of the urate ring backbone largely contributes to stress mitigation.

[0060] Compounds with three (meth)acryloyl groups and a urate ring skeleton are also relatively easy to obtain, but due to their low crosslinking density, they are not suitable because the surface hardness or scratch resistance of the hard coating is insufficient.

[0061] As a polyfunctional urethane (meth)acrylate (a1), specifically, examples include the reaction product of isocyanurate (trimer) of diisocyanate with poly(meth)acrylate compound having hydroxyl groups, and the reaction product of isocyanurate (trimer) of polyisocyanate with polyol and poly(meth)acrylate compound or mono(meth)acrylate compound having hydroxyl groups. From the viewpoint of excellent hardness or scratch resistance of the hard coating film surface, the reaction product of isocyanurate (trimer) of diisocyanate with poly(meth)acrylate compound having one hydroxyl group and two or more (meth)acryloyl groups is preferred.

[0062] Examples of diisocyanates include: aromatic diisocyanates such as toluene diisocyanate, xylene diisocyanate and diphenylmethane diisocyanate, hydrogenated forms of the aromatic isocyanates, and aliphatic diisocyanates such as isophorone diisocyanate and hexamethylene diisocyanate.

[0063] Examples of mono(meth)acrylates having one hydroxyl group include: 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, and 4-hydroxybutyl(meth)acrylate.

[0064] Examples of poly(meth)acrylates having one hydroxyl group include pentaerythritol tri(meth)acrylate and dipentaerythritol penta(meth)acrylate, but are not limited to these.

[0065] Examples of polyols include ethylene glycol, polyethylene glycol, polypropylene glycol, glycerol, trimethylolpropane, cyclohexanediol, cyclohexanediethanol and tricyclodecanediethanol, but are not limited to these.

[0066] <Polyfunctional carbamate (meth)acrylate (a2)>

[0067] The polyfunctional urethane (meth)acrylate (a2) is a polyfunctional urethane (meth)acrylate (excluding (a1)) having 4 or more but less than 15 (meth)acryloyl groups and a weight average molecular weight of 500 to 15,000. The weight average molecular weight is preferably 1,000 to 5,000. The weight average molecular weight (Mw) is the weight average molecular weight converted from polystyrene, determined by gel permeation chromatography (GPC). The weight average molecular weight can be determined using the method described in [Example].

[0068] Multifunctional urethane (meth)acrylate (a2) can achieve a balance of crosslinking density, flexibility, and substrate adhesion when used in combination with multifunctional urethane (meth)acrylate (a1), which can reduce damage, curling (warping), and dissolution and degradation of UV blockers.

[0069] Examples of polyfunctional urethane (meth)acrylates (a2) include: substances obtained by reacting polyisocyanates with mono(meth)acrylates or poly(meth)acrylates having hydroxyl groups; urethane prepolymers containing isocyanate groups obtained by reacting polyols with polyisocyanates under conditions of excess isocyanate groups; and substances obtained by reacting mono(meth)acrylates or poly(meth)acrylates having hydroxyl groups.

[0070] Alternatively, it can be obtained by reacting a polyol with a polyisocyanate under conditions of excess hydroxyl groups to form a hydroxyl-containing urethane prepolymer, and by reacting it with a (meth)acrylate having an isocyanate group.

[0071] The following describes a method for manufacturing urethane (meth)acrylate (a2), but it is only one example and is not limited to these. For example, urethane (meth)acrylate (a2) can be obtained by stirring polyisocyanate and hydroxyl-containing (meth)acrylate in the presence of a suitable urethane esterification catalyst under oxygen conditions at 60°C to 100°C for 4 to 8 hours.

[0072] Specific examples of carbamate esterification catalysts include: copper naphthenate, cobalt naphthenate, zinc naphthenate, dibutyltin dilaurate, triethylamine, 1,4-diazabicyclo[2.2.2]octane, and 2,6,7-trimethyl-1,4-diazabicyclo[2.2.2]octane. Among these, dibutyltin dilaurate is particularly preferred.

[0073] Examples of polyisocyanates include aliphatic diisocyanates and aromatic diisocyanates. Examples of aliphatic diisocyanates include hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated xylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. Examples of aromatic diisocyanates include toluene diisocyanate, xylene diisocyanate, and diphenylmethane diisocyanate. The bonding position between the isocyanate group and the aromatic group can be any of the ortho, meta, or para positions. Furthermore, the diisocyanate can also form an isocyanurate ring as a trimer.

[0074] From the perspective of suppressing yellowing for optical applications, aliphatic diisocyanates are preferred.

[0075] The number of (meth)acryloyl groups and the weight-average molecular weight can be adjusted by combining polyols, polyisocyanates, and hydroxyl-containing mono(meth)acrylates or poly(meth)acrylates.

[0076] Examples of hydroxyl-containing (meth)acrylates include: trimethylolpropane di(meth)acrylate, trimethylolethane di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, 2-hydroxyethyl (meth)acrylate, 1-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 1-hydroxybutyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, etc. 8-Hydroxyoctyl methacrylate, cyclohexanediol mono(meth)acrylate, 10-Hydroxydecyl methacrylate, 12-Hydroxylaurate methacrylate, ethyl-α-(hydroxymethyl) methacrylate, monofunctional glycerol methacrylate, or methacrylates with hydroxyl groups at the end obtained by ring-opening addition of these methacrylates to ε-caprolactone, or hydroxyl-containing methacrylates such as alkylene oxide addition methacrylates formed by repeated addition of hydroxyl-containing methacrylates to ethylene oxide, propylene oxide, butylene oxide, etc.

[0077] From the viewpoints of increasing crosslinking density, suppressing damage, preventing curling, and reducing the dissolution of UV blocking agents, (meth)acrylates having 2 to 5 (meth)acryloyl groups are preferred. Specifically, it is preferred to contain at least one selected from trimethylolpropane di(meth)acrylate, trimethylolethane di(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol penta(meth)acrylate.

[0078] Examples of polyfunctional carbamate (meth)acrylates (a2) whose molecular weight and number of acryloyl groups are disclosed in catalogs and other publications include: UV1700B (molecular weight 2000, number of acryloyl groups 10), UV7600B (molecular weight 1400, number of acryloyl groups 6), UV7605B (molecular weight 1100, number of acryloyl groups 6), UV7610B (molecular weight 1100, number of acryloyl groups 9), UV7629EA (molecular weight 4100, number of acryloyl groups 9, volatile content 35%), and UV7640B (molecular weight 1...) manufactured by Mitsubishi Chemical Co., Ltd. 500 (6-7 acryloyl groups), and UV7650B (2300 molecular weight, 4-5 acryloyl groups), Miramer PU610 (1800 molecular weight, 6 acryloyl groups) and MU9500 (3200 molecular weight, 10 acryloyl groups) manufactured by Miwon (stock), and Kayarad DPHA-40H (2000 molecular weight, 6 acryloyl groups) manufactured by Nippon Kayaku (stock). 10), UX-5000 (molecular weight 1500, number of acryloyl groups 6), UX-5102D-M20 (molecular weight 3500, number of acryloyl groups 6, volatile components 20%), UX-5103 (molecular weight 7000, number of acryloyl groups 6), and UX-5005 (molecular weight 4500, number of acryloyl groups 9), and ArtResin UN-3320HA (molecular weight 1500, number of acryloyl groups 9) manufactured by Genjo Industries (Co., Ltd.) The list includes, but is not limited to, UN-3320HC (molecular weight 1500, number of acryloyl groups 15, volatile components 5%), UN-904 (molecular weight 4900, number of acryloyl groups 10), UN-906S (molecular weight 1000, number of acryloyl groups 6), UN-901T (molecular weight 4000, number of acryloyl groups 9, volatile components 20%), and UN-952 (molecular weight 6500-11000, number of acryloyl groups 10), etc.

[0079] <Polyfunctional (meth)acrylates (a3)>

[0080] The polyfunctional (meth)acrylate (a3) ​​is another polyfunctional (meth)acrylate besides (a1) and (a2).

[0081] As for polyfunctional (meth)acrylates (a3), various diol (meth)acrylates, trimethylolethane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and other polyol poly(meth)acrylates, tri(meth)acrylates of isocyanurates of various diisocyanates, polyfunctional urethane (meth)acrylates (a1), and urethane acrylates other than polyfunctional urethane (meth)acrylates (a2) can be listed, but are not limited to these.

[0082] The residual pentaerythritol triacrylate (a3-1), pentaerythritol tetraacrylate (a3-2), dipentaerythritol pentaacrylate (a3-3), and dipentaerythritol hexaacrylate (a3-4) from the synthesis of polyfunctional urethane (meth)acrylate (a1) and polyfunctional urethane (meth)acrylate (a2) can be used directly.

[0083] As a polyfunctional (meth)acrylate (a3), examples include polyfunctional acrylates having 2 to 5 (meth)acryloyl groups and a urate ring skeleton.

[0084] Dong-A Synthetic Co., Ltd. manufactures Aronix M-215 and other isocyanuric acid ethylene oxide (EO) modified diacrylates (acryloyl group count 2).

[0085] Dong-A Synthetic's Aronix M-313 and Aronix M-315 are EO-modified diacrylates and triacrylates (acryloyl groups 2-3) of isocyanuric acid.

[0086] Shin-Nakamura Chemical Co., Ltd. manufactures NK ester A-9300-1CL and other ε-caprolactone-modified (2-acryloyloxy) isocyanurate esters (acryloyl group number 3), and...

[0087] Tris(2-acryloyloxyethyl) isocyanurates (acryloyl group number 3) manufactured by Shin-Nakamura Chemical Co., Ltd. include NK ester A-9300, Arkema Co., Ltd. including SARTOMER SR368, Daiichi Kogyo Pharmaceutical Co., Ltd. including NEW FRONTIER TEICA (GX-8430), and Showa Denko Co., Ltd. including FANCRYL FA-731A, but are not limited to these.

[0088] In addition, examples of polyfunctional (meth)acrylates (a3) ​​include polyfunctional carbamate acrylates that are outside the range of 4 to 15 (meth)acryloyl groups or have a weight average molecular weight outside the range of 500 to 15,000.

[0089] The products manufactured by Mitsubishi Chemical (stock) include UV-6300B (molecular weight 3700, number of acryloyl groups 3), ArtResin UN-5500 (molecular weight 50000, number of acryloyl groups 12.5, volatile content 50%), UN-5507 (molecular weight 17000, number of acryloyl groups 15.5, volatile content 50%), and UN-905 (molecular weight 40000-200000, number of acryloyl groups 15, volatile content 40%), and Miramer SC2152 (molecular weight 20787, number of acryloyl groups 15), etc., but are not limited to these.

[0090] The mass ratio (a1) / (a2) of the polyfunctional urethane (meth)acrylate (a1) to polyfunctional urethane (meth)acrylate (a2) contained in the active energy line curing component (A) is preferably 20 / 80 to 80 / 20, more preferably 60 / 40 to 40 / 60. By setting (a1) / (a2) to 20 / 80 to 80 / 20, damage during the process, dissolution of the UV blocking agent, and reduction in adhesion to the substrate and curling can be suppressed.

[0091] The preferred contents of polyfunctional urethane (meth)acrylate (a1), polyfunctional urethane (meth)acrylate (a2), and polyfunctional (meth)acrylate (a3) ​​in 100% by mass of the active energy line curing component (A) are as follows: polyfunctional urethane (meth)acrylate (a1) is 12% to 48% by mass, polyfunctional urethane (meth)acrylate (a2) is 20% to 80% by mass, and polyfunctional (meth)acrylate (a3) ​​is 8% to 32% by mass. By adjusting to the above ranges, high damage prevention, high substrate adhesion, suppression of curling, and suppression of dissolution of ultraviolet blocking agents can be achieved.

[0092] UV Blocking Agent (B)

[0093] As a UV blocking agent (B), it is preferable to be a substance with excellent UV absorption capacity at a low addition amount in terms of preventing leaching, preventing dissolution in the saponification process, and price.

[0094] Examples of such UV blocking agents include benzotriazole, hydroxyphenyltriazine, and benzophenone.

[0095] In terms of minimizing adverse effects on other physical properties of the coating, hydroxyphenyltriazine-based or benzotriazole-based UV blockers are preferred. These UV blockers can be commercially available products, or a mixture of two or more commercially available products can be used. Examples of commercially available UV blocking agents include: Ciba Specialty Chemicals (Ciba)'s "TINUVIN" series (benzotriazole and hydroxyphenyl triazine), "CHIMASSORB" series; BASF's "UVINUL" series (benzophenone and triazine), "RUVA" series (benzotriazole), "Adekastab LA" series (benzotriazole and triazine), and Everlight Chemicals' "Eversorb" series (benzotriazole, triazine, and benzophenone).

[0096] Relative to 100% by mass of the active energy line curing component (A), the content of the ultraviolet blocking agent (B) is, for example, 0.5% to 20% by mass, preferably in the range of 2% to 15% by mass. By setting it to 0.5% to 20% by mass, the curability of the coating film can be improved while ensuring the ultraviolet light required for photoexcitation of the photopolymerization initiator, thus effectively blocking ultraviolet light.

[0097] Photopolymerization Initiator (C)

[0098] Photopolymerization initiators (C) are not particularly limited as long as they possess the function of initiating free radical polymerization through photoexcitation. Examples include: acetophenone compounds, benzoin compounds, benzophenone compounds, phosphine oxide compounds, ketal compounds, anthraquinone compounds, thioxanthone compounds, etc. Specifically, examples include: benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, diethoxyacetophenone, benzoin dimethyl ketal, 1-hydroxycyclohexylphenyl ketone, benzophenone, 2,4,6-trimethylbenzoin diphenylphosphine oxide, N,N-dimethylaminobenzoate isoamyl ester, 2-chlorothioxanthone, 2,4-diethylthioxanthone, etc.

[0099] In addition, thioxanone compounds function as photopolymerization initiators when used alone, but also as photosensitizers when used in combination with other photopolymerization initiators.

[0100] The active energy line-curing composition of the present invention blocks ultraviolet light with a wavelength near 400 nm, which affects the laminate, by including an ultraviolet blocking agent. This also blocks the ultraviolet light required for photoexcitation of the photopolymerization initiator. Therefore, a highly sensitive initiator that can efficiently generate free radicals with as little ultraviolet light as possible, even in minute amounts, is preferred. Specifically, preferred materials include dialkylaminobenzophenone derivatives such as 4,4'-bis(dimethylamino)benzophenone and 4,4'-bis(diethylamino)benzophenone, camphorquinone derivatives such as (±)-camphorquinone, thioxanthone derivatives such as Ultracure CTX and Ultracure DTX manufactured by Sherwin-Williams, Quantacure ITX manufactured by Ward-Blenkinsop, isopropylthioxanthone, thioxanthone derivatives such as 2,4-diethylthioxanthone, anthraquinone derivatives such as TBA and 2-ethylanthraquinone manufactured by BASF, and oxime ester derivatives such as Irgacure OXE01, Irgacure OXE02, and Irgacure OXE03 manufactured by BASF. Oxime ester derivatives are particularly preferred.

[0101] The amount of photopolymerization initiator (C) is preferably 0.1% to 30% by mass, more preferably 5% to 20% by mass, relative to 100% by mass of the active energy line hardening component (A). Within this range, sufficient polymerization initiation effect can be obtained, which is effective in improving adhesion or scratch resistance.

[0102] <Senser (F)>

[0103] The hard coating forming composition of the present invention can use a photopolymerization initiator (C) and a sensitizer in combination. Examples of sensitizers include amine sensitizers, anthracene sensitizers, thioxanthone sensitizers, etc. Sensitizers can be used alone or in combination of two or more.

[0104] Examples of amine sensitizers include: trimethylamine, methyldiethanolamine, triethanolamine, p-diethylaminobenzophenone, p-dimethylaminobenzoic acid ethyl ester (EPA), p-dimethylaminobenzoic acid isoamyl ester, 4-dimethylaminobenzoic acid ethyl ester, N,N-dimethylbenzylamine, 4'-bis(diethylamino)benzophenone, etc.

[0105] Examples of anthracene sensitizers include: 9,10-dibutoxyanthracene (DBA), 9,10-diethoxyanthracene (DEA), 9,10-dipropoxyanthracene, and 9,10-bis(2-ethylhexyloxy)anthracene.

[0106] Examples of thioxanthone sensitizers include 2,4-diethylthioxanthone (DETX), 2-isopropylthioxanthone (ITX), and 4-isopropylthioxanthone.

[0107] Examples of commercially available products include amine sensitizers such as KAYACURE EPA manufactured by Nippon Kayaku Co., Ltd., anthracene sensitizers such as Anthracure UVS-1331 (DBA) and UVS-1101 (DEA) manufactured by Air Water Performance Chemical Co., Ltd., and thioxanthone sensitizers such as Omnirad DETX and ITX manufactured by IGM Resins BV.

[0108] The preferred sensitizer is one that absorbs up to approximately 420 nm, a wavelength longer than the UV cutoff region, and is preferably a thioxanthone-based sensitizer or a combination of an amine-based sensitizer and a thioxanthone-based sensitizer.

[0109] When using a sensitizer, its content is preferably 1% to 15% by mass relative to 100% by mass of the active energy line hardening component (A).

[0110] Solvent (D)

[0111] Solvent (D) includes solvent (d1) that satisfies the following formula (1) and solvent (d2) other than solvent (d1).

[0112] Equation (1) [(X2) / (X1)] ≥ 0.25

[0113] (X1): Haze value of an 80 μm thick triacetylcellulose membrane without added solvent.

[0114] (X2): Haze value of an 80 μm thick triacetylcellulose membrane after solvent addition and drying.

[0115] The determination methods for (X1) and (X2) are described in detail in the [Example] section.

[0116] Examples of solvents (d1) include: dimethyl carbonate (0.31), ethyl acetate (0.63), n-butyl acetate (0.53), acetone (0.97), methyl ethyl ketone (0.58), 1,3-dioxolane (0.64), etc., but are not limited to these. One or more of these can be used alone or in combination.

[0117] Solvents other than solvent (d1) (d2) include: methyl isobutyl ketone (0.17), isopropanol (0.20), propylene glycol monomethyl ether (0.15), propylene glycol monomethyl ether acetate (0.14), etc., but are not limited to these.

[0118] The upper limit of the haze change value [(X2) / (X1)] is preferably 0.90 or less, and more preferably 0.60 or less. By using a solvent (D) that satisfies the above upper limit, the substrate permeability of the active energy line curing composition for hard coating formation is improved without reducing the haze or scratch resistance of the coating film, which is effective in improving adhesion or reducing interference unevenness.

[0119] The solvent (d1) content in 100% by mass of solvent (D) is preferably 50% by mass or more and less than 100% by mass. If 50% by mass and less than 100% by mass of solvent (d1) are included in 100% by mass of solvent (D), the active energy line-curing composition for hard coating formation, together with solvent (d1), penetrates into the TAC membrane, forming a mixed layer of the composition and the TAC membrane. This improves the adhesion between the TAC membrane and the hard coating, thereby effectively preventing the leaching of the ultraviolet (UV) cutoff agent during the saponification process. Furthermore, by using solvent (d2) in combination, the viscosity, coatability, and drying properties of the active energy line-curing composition for hard coating formation can be adjusted.

[0120] The solvent (D) is preferably 40% to 80% by mass in 100% by mass of the active energy line curing component (A) composition for hard coating formation, more preferably 40% to 70% by mass, and even more preferably 45% to 65% by mass. If it is 40% by mass or more, the substrate permeability is high, thereby further improving the adhesion. If it is 80% by mass or less, the substrate permeability is not too high, which can further suppress the deterioration of coating haze or scratch resistance.

[0121] [Active Energy Line Curing Composition for Hard Coating Formation (Composition for Hard Coating Formation)]

[0122] The active energy line curing composition for forming a hard coating of the present invention contains: an active energy line curing component (A), an ultraviolet blocking agent (B), a photopolymerization initiator (C), and a solvent (D).

[0123] The hard coating forming composition of the present invention may contain other additives as needed. Other additives include, for example, plasticizers, surface modifiers, light stabilizers, antioxidants, and polymerization inhibitors.

[0124] [Hard coating]

[0125] The hard coating of the present invention has a hard coating formed on a triacetylcellulose membrane by an active energy line curing composition for forming the hard coating.

[0126] The hard coating of the present invention preferably has a transmittance (ta) of less than 4% at a wavelength of 380nm and a transmittance (tb) of more than 70% at a wavelength of 420nm.

[0127] From the perspective of suppressing yellowing, the transmittance (tb) is more preferably 75% or more, and even more preferably 80% or more.

[0128] By achieving a transmittance (ta) of less than 4% at a wavelength of 380nm, harmful ultraviolet light in the ultraviolet region below 380nm can be blocked, preventing degradation of the organic EL display. Furthermore, by achieving a transmittance (tb) of more than 70% at a wavelength of 420nm, accurate color reproduction of the organic EL display's display unit can be achieved.

[0129] Furthermore, the hard coating of the present invention preferably satisfies the following formula (2).

[0130] Equation (2) (tc)-(ta)≦1%

[0131] (ta): Transmittance of the hard coating film not immersed in sodium hydroxide aqueous solution at a wavelength of 380 nm.

[0132] (tc): Transmittance of the hard coating film at a wavelength of 380 nm after immersion in an aqueous sodium hydroxide solution, washing with water, and drying.

[0133] By ensuring that (tc)-(ta)≦1%, the leaching of UV blockers into the saponification solution can be reduced while protecting organic EL displays from harmful ultraviolet radiation. The determination methods for (ta) and (tc) are described in detail in the [Examples] section.

[0134] <Triacetylcellulose membrane>

[0135] The triacetylcellulose membrane used in this invention only needs to be optically transparent. There are no particular limitations on the thickness of the triacetylcellulose membrane; typically, in terms of strength, operability, and thinness, it is around 10 μm to 500 μm. Particularly preferred is 20 μm to 250 μm.

[0136] <Manufacturing of Hard Coatings>

[0137] Regarding the manufacturing method of the hard coating film, it can be manufactured by existing known methods such as coating a hard coating layer composition onto a triacetylcellulose membrane, and there are no particular limitations.

[0138] For example, after applying the hard coating forming composition of the present invention onto a triacetylcellulose membrane, the solvent is dried as needed. The membrane is then irradiated with active energy lines, thereby causing the applied hard coating forming composition to crosslink and harden, resulting in a hard coating film having a triacetylcellulose membrane, a mixed layer, and a hard coating.

[0139] Examples of coating methods include: bar coating, scraper coating, spin coating, reverse coating, die coating, spray coating, roller coating, gravure coating, micro-gravure coating, die lip coating, air knife coating, and impregnation.

[0140] As an active energy beam, it can use electron beams or ultraviolet light emitted from sources such as xenon lamps, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, carbon arc lamps, and tungsten lamps.

[0141] The thickness of the hard coating is not particularly limited as long as it maintains its hard coating properties; it is typically 1 μm to 20 μm, preferably 2 μm to 15 μm. The thickness of the film obtained by adding the hard coating and the hybrid layer is also not particularly limited; to reduce interference unevenness, it is preferably 0.5 μm to 100 μm, more preferably 1.1 μm to 30 μm, and even more preferably 1.2 μm to 25 μm.

[0142] There is no particular limitation on the thickness of the hard coating film, but it is preferably 50 μm to 300 μm, more preferably 81 μm to 100 μm, and even more preferably 82 μm to 95 μm.

[0143] [Layered Body]

[0144] The laminate of the present invention has a structure in which a hard coating film and a circular polarizing functional layer are laminated. That is, it has a structure of hard coating film / triacetyl cellulose film / circular polarizing functional layer.

[0145] The circular polarizing functional layer has a stacked structure of a PVA polarizer and a phase retardation layer, wherein the phase retardation layer can be a phase retardation accumulator (TAC) with phase retardation function. The phase retardation accumulator (TAC) can also serve as the TAC constituting the hard coating film. That is, the structure of hard coating / phase retardation accumulator (TAC) / PVA polarizer is also equivalent to the stacked structure of the present invention.

[0146] There are no particular limitations on the manufacturing method of the laminate. For example, a circular polarizing functional layer laminate can be formed by bonding a triacetyl cellulose membrane without a hard coating to a PVA polarizer.

[0147] Figure 1 The diagram shows an example of the structure of an organic EL display, which is an example of the use of the laminate of the present invention. Figure 1In the diagram, 1 is a transparent optical material layer, 2 is a hard coating layer, 3 is TAC, 4 is a polarizer (PVA), 5 is a phase retardation layer, and 6 is a structure containing an organic EL light-emitting layer.

[0148] Figure 1 Sometimes, overlapping latex, adhesives, or bonding agents are used to attach items between 1 and 2, or between 5 and 6.

[0149] Figure 2 The diagram shows an example of the structure of an organic EL display, which is an example of the use of the laminate of the present invention. Figure 2 In the diagram, 1 is the transparent optical material layer, 2 is the hard coating layer, 4 is the polarizer (PVA), 6 is the organic EL light-emitting layer, and 7 is the phase difference TAC.

[0150] Figure 2 Sometimes, the 2 and 6 are attached by using overlapping latex, adhesive, or bonding agent.

[0151] [Example]

[0152] <Weight-average molecular weight (Mw)>

[0153] The weight-average molecular weight was determined using a gel permeation chromatography system (HLC-8220GPC) manufactured by Tosoh Corporation. Four separation columns (TSK-GEL SUPER H5000, TSK-GEL SUPER H4000, TSK-GEL SUPER H3000, and TSK-GEL SUPER H2000) manufactured by Tosoh Corporation were connected in series. The mobile phase was tetrahydrofuran at 40°C, and the flow rate was 0.6 ml / min.

[0154] < Haze change of solvent (D) [(X2) / (X1)]>

[0155] The haze change value of solvent (D) [(X2) / (X1)] is obtained using the following method.

[0156] Calculate the haze value (X1) of an untreated (solvent-free) 80 μm thick triacetylcellulose membrane, and the haze value (X2) of a triacetylcellulose membrane after adding 0.1 g of solvent (D) to a 10 cm long side × 10 cm long side × 80 μm thick triacetylcellulose membrane and placing it at 25 °C for 2 minutes and then heating it at 60 °C for 1 minute [(X2) / (X1)].

[0157] <Determination of Haze Value>

[0158] Using a spectrophotometer / haze meter “SH 7000” manufactured by Nippon Denshoku Kogyo Co., Ltd., installed in a constant temperature and humidity chamber at 23°C and 50% relative humidity (50% RH), the average value of the measurements taken under a D65 light source with n=3 was set as the haze value.

[0159] <Measurement of transmittance>

[0160] The composition for forming a hard coating layer was obtained by coating a 50 μm thick triacetyl cellulose membrane with a transmittance of 8% or more at 380 nm and containing a UV blocker using a bar coater No. 8. After drying in a hot air oven for 1 minute, the coating layer was hardened by irradiating with ultraviolet light using a high-pressure mercury lamp with a power of 80 W / cm, thus obtaining a hard coating film having a triacetyl cellulose membrane and a hard coating layer.

[0161] The transmittance at 380 nm and 420 nm of the hard coating film with hard coating was measured using a Hitachi High-Tech (UH5200) spectrophotometer set in a constant temperature and humidity chamber at 23°C and 50% RH.

[0162] <Transmittance difference of hard coating [(tc)-(ta)]>

[0163] The hard coating film was immersed in a 9wt% NaOH aqueous solution at 50℃ for 5 minutes, washed with water, and then dried in a box oven at 100℃ for 5 minutes. The transmittance (tc) at a wavelength of 380nm was then measured. The difference between the transmittance (tc) and the transmittance (ta) at a wavelength of 380nm of the untreated (not immersed in sodium hydroxide aqueous solution) hard coating film was calculated.

[0164] <Manufacturing of polyfunctional carbamate (meth)acrylates (a1)>

[0165] (Synthesis Example 1) Carbamate-acrylate mixture (P1): In a four-necked flask including a stirrer, reflux cooler, nitrogen inlet tube, thermometer, and dropping funnel, 1325.6 parts by mass of Aronix M306 (manufactured by Toa Synthetic Co., Ltd., containing 67.5% by mass of pentaerythritol triacrylate (PE-3A)(a3-1) with a molecular weight of 298 and 32.5% by mass of pentaerythritol tetraacrylate (PE-4A)(a3-2) with a molecular weight of 352, and 0.1 parts by mass of Neostann U-810 (manufactured by Nitto Kasei Co., Ltd., tin catalyst) were added dropwise over 30 minutes. After the liquid temperature reached 50°C, Desmodur Z4470BA (manufactured by Sumika Covestro) was added dropwise. Covestro (stock) manufactures 1109.8 parts by mass of a polyisocyanate with a urate ring, comprising 70% by mass of non-volatile components (volatile component butyl acetate), 85.8% by mass of isophorone diisocyanate (IPDI) trimer with a molecular weight of 667 relative to the non-volatile components, and 11.9% by mass of NCO.

[0166] After the heating was completed, the temperature was raised to 80°C and reacted for 3 hours. After the disappearance of the isocyanate group peak was confirmed by Fourier transform infrared spectroscopy (FT-IR), the temperature was lowered to room temperature to obtain a urethane acrylate mixture (P1) with a nonvolatile component of 77.1% by mass of urethane acrylate with 9 acryloyl groups and a weight average molecular weight of 1600 (a1-1), 20.8% by mass of pentaerythritol tetraacrylate (PE-4A) (a3-2), and 2.1% by mass of other compounds without (meth)acryloyl groups (e-1).

[0167] (Synthesis Example 2) Carbamate-acrylate mixture (P2): In a four-necked flask including a stirrer, reflux cooler, nitrogen inlet tube, thermometer, and dropping funnel, 1325.6 parts by mass of Aronix M306 and 0.1 parts by mass of Neostann U-810 were placed. After the liquid temperature reached 50°C, 571.7 parts by mass of Durnate TPA-100 (manufactured by Asahi Kasei Corporation, 100% by mass of non-volatile components, containing 88.3% by mass of hexamethylene diisocyanate (HDI) trimer with a molecular weight of 505 and an NCO content of 23.1%) were added dropwise over 30 minutes.

[0168] After the heating was completed, the temperature was raised to 80°C and reacted for 3 hours. After the isocyanate group peak disappeared in FT-IR, the temperature was lowered to room temperature to obtain a 100% non-volatile urethane acrylate mixture (P2) containing 76.1% by mass of a urethane acrylate with 9 acryloyl groups and a weight average molecular weight of 1400 (a1-2), 23.0% by mass of pentaerythritol tetraacrylate (PE-4A) (a3-2), and 0.9% by mass of other compounds without (meth)acryloyl groups (e-2).

[0169] (Synthesis Example 3) Carbamate-acrylate mixture (P3): In a four-necked flask including a stirrer, reflux cooler, nitrogen inlet tube, thermometer, and dropping funnel, 4439.0 parts by weight of Desmodur Z4470BA, 432.6 parts by weight of cyclohexyldiethanol (molecular weight 144, hydroxyl value 389 mg KOH / g), and Neostann U-810 were added. 0.1 parts by mass were heated to 80°C and reacted for 3 hours. After confirming by FT-IR that the peak intensity of the isocyanate group had become half of that before the reaction, 865.0 parts by mass of 4-hydroxybutyl acrylate (molecular weight 144, hydroxyl value 389 mg KOH / g) were added. The mixture was then reacted at 80°C for 3 hours. After confirming by FT-IR that the peak of the isocyanate group had disappeared, the temperature was lowered to room temperature to obtain a urethane acrylate mixture (P3) containing 96.0% by mass of urethane acrylate with 6 acryloyl groups and a weight average molecular weight of 4000 and 4.0% by mass of other compounds (e-3) without (meth)acryloyl groups, with a nonvolatile component of 100.0% by mass.

[0170] <Manufacturing of polyfunctional carbamate (meth)acrylates (a2) having 4 or more but less than 15 (meth)acryloyl groups and a weight average molecular weight of 500 to 15,000>

[0171] (Synthesis Example 4) Carbamate-acrylate mixture (Q1): In a four-necked flask including a stirrer, reflux cooler, nitrogen inlet tube, thermometer, and dropping funnel, 533 parts by mass of pentaerythritol triacrylate (manufactured by Thermo Fisher Scientific, pentaerythritol triacrylate (PE-3A), purity ≥ 97%, molecular weight 298), 237 parts by mass of a mixture of Aronix M306 and 32.5% by mass, and 0.1 parts by mass of Neostann U-810 were added. After the liquid temperature was set to 50°C, 224 parts by mass of Desmodur I (manufactured by Sumika Covestro, Inc., isophorone diisocyanate (IPDI)) were added dropwise over 30 minutes. After the heating was completed, the temperature was raised to 80°C and reacted for 3 hours. After the isocyanate group peak disappeared in FT-IR, the temperature was lowered to room temperature to obtain a urethane acrylate mixture (Q1) containing 82.6% by mass of urethane acrylate with a molecular weight of 900 and 6 acryloyl groups (a2-1) (acryloyl equivalent 137), 9.7% by mass of pentaerythritol triacrylate (a3-1) (PE-3A, acryloyl equivalent 99), and 7.7% by mass of pentaerythritol tetraacrylate (a3-2) (PE-4A, acryloyl equivalent 88).

[0172] (Synthetic Example 5) Carbamate-acrylate mixture (Q2): In a four-necked flask including a stirrer, reflux cooler, nitrogen inlet tube, thermometer, and dropping funnel, 2500 parts by mass of Aronix M403 (manufactured by Dong-A Synthetic Co., Ltd., a mixture of 55% by mass of dipentaerythritol pentaacrylate (DPPA(a3-3)) with a molecular weight of 524 and 45% by mass of dipentaerythritol hexaacrylate (DPHA(a3-4)) with a molecular weight of 579) and 0.1 parts by mass of Neostann U-810 were added. After the liquid temperature was brought to 50°C, 224 parts by mass of Desmodur I were added dropwise from the dropping funnel over 30 minutes. After the heating was completed, the temperature was raised to 80°C and reacted for 3 hours. After the isocyanate group peak disappeared in FT-IR, the temperature was lowered to room temperature to obtain a urethane acrylate mixture (Q2) containing 46.7% by mass of urethane acrylate (a2-2) (acryloyl equivalent 127) with a molecular weight of 1300 and 10 acryloyl groups, 12.0% by mass of dipentaerythritol pentaacrylate (a3-3) (DPPA, acryloyl equivalent 105) and 41.3% by mass of dipentaerythritol hexaacrylate (a3-4) (DPHA, acryloyl equivalent 96).

[0173] The materials used in the embodiments and comparative examples are described below.

[0174] <Polyfunctional carbamate (meth)acrylate (a1)>

[0175] •(a1-1): Molecular weight 1600, number of acryloyl groups 9

[0176] •(a1-2): Molecular weight 1400, number of acryloyl groups 9

[0177] •(a1-3): Molecular weight 4000, number of acryloyl groups 6

[0178] <Polyfunctional carbamate (meth)acrylate (a2)>

[0179] (a2-1): Molecular weight 900, number of acryloyl groups 6

[0180] •(a2-2): Molecular weight 1300, number of acryloyl groups 10

[0181] <Polyfunctional (meth)acrylates (a3)>

[0182] • (a3-1): Pentaerythritol triacrylate (PE-3A)

[0183] •(a3-2): Pentaerythritol tetraacrylate (PE-4A)

[0184] •(a3-3): Dipentaerythritol pentaacrylate (DPPA)

[0185] • (a3-4): Dipentaerythritol tetraacrylate (DPHA)

[0186] • Multifunctional acrylate liquid (R1): Aronix M-403 (a mixture of 55% dipentaerythritol pentaacrylate (a3-3) and 45% dipentaerythritol tetraacrylate (a3-4)) manufactured by Toa Synthetic Co., Ltd.

[0187] • Multifunctional acrylate liquid (R2): Sartomer SR368 manufactured by Arkema (stock) (molecular weight 423, number of acryloyl groups 3, (a3-5))

[0188] • Multifunctional acrylate liquid (R3): ArtResin UN-5507 manufactured by Genjo Kogyo (stock) (molecular weight 17000, number of acryloyl groups 15.5, (a3-5), containing 50% n-butyl acetate).

[0189] <UV blocking agent (B)>

[0190] • UV blocking agent (b-1): UVINUL 3050 manufactured by BASF: a benzophenone-based UV blocking agent

[0191] <Photopolymerization Initiator (C)>

[0192] • (c-1): ESACURE ONE manufactured by IGM Resins BV: oligomeric [2-hydroxy-2-methyl-[1-(methylvinyl)phenyl]acetone

[0193] • (c-2): DAIDO UV-CURE APO: diphenyl-2,4,6-trimethylbenzoylphosphine oxide manufactured by Daido Chemical Industries, Ltd.

[0194] • (c-3): Irgacure OXE01 manufactured by BASF (stock): 1-[4-(phenylthio)phenyl]octane-1,2-dione=2-(O-benzoyl oxime)

[0195] • (c-4): Irgacure OXE03, an oxime ester-based photopolymerization initiator manufactured by BASF (stock).

[0196] • (c-5): Omnirad 907 manufactured with IGM Resins BV: 2-Methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropane-1-one

[0197] <Senser (F)>

[0198] •(f): Omnirad DETX: 2,4-diethylthioxanone manufactured with IGM Resins BV

[0199] <Solvent (D)>

[0200] The value in parentheses is the haze change value [(X2) / (X1)].

[0201] (The solvent (d1) satisfies [(X2) / (X1)]≧0.25)

[0202] ·(d1-1) Butyl acetate (manufactured by Daicel (stock), 0.53)

[0203] • (d1-2)DMC: Dimethyl carbonate (manufactured by Ube Industries, Inc., 0.31)

[0204] • (d1-3)MEK: Methyl ethyl ketone (manufactured by Maruzen Petrochemical Co., Ltd., 0.58)

[0205] (Solvent (d2) that does not satisfy [(X2) / (X1)]≧0.25)

[0206] (d2-1)MIBK: Methyl isobutyl ketone (manufactured by Mitsubishi Chemical Co., Ltd., 0.17)

[0207] ·(d2-2)PGM: Propylene glycol monomethyl ether (manufactured by Dashin Chemical Co., Ltd., 0.15)

[0208] • (d2-3)PIGMAC: Propylene glycol monomethyl ether acetate (manufactured by Sankyo Chemical Co., Ltd., 0.14)

[0209] <Example 1>

[0210] Add 20.9 parts of urethane acrylate mixture (P1), 67.8 parts of urethane acrylate mixture (Q1), 14.4 parts of multifunctional acrylate solution (R1), 10 parts of UV cutoff agent UVINUL 3050 (b-1), 7.0 parts of photopolymerization initiator ESACURE ONE (c-1), 3.0 parts of photopolymerization initiator APO (c-2), 35 parts of dimethyl carbonate (d1-2), 12.2 parts of methyl isobutyl ketone (d1-3), 40 parts of methyl ethyl ketone (d2-1), and 10 parts of propylene glycol monomethyl ether (d2-2) to a flask equipped with a stirrer, and stir to obtain a hard coating forming composition containing the following compounds.

[0211] • Carbamate acrylate (a1-1): 14 parts

[0212] • Carbamate acrylate (a2-1): 56 parts

[0213] • Pentaerythritol triacrylate (a3-1): 6.6 parts

[0214] • Pentaerythritol tetraacrylate (a3-2): 9.0 parts

[0215] • Dipentaerythritol pentaacrylate (a3-3): 7.9 parts

[0216] • Dipentaerythritol hexaacrylate (a3-4): 6.5 parts

[0217] The above contains 100 portions of active energy line hardening component (A).

[0218] Other non-volatile components: 0.3 parts

[0219] • UV blocking agent UVINUL 3035(b-1): 10 parts

[0220] • Photopolymerization initiator ESACURE ONE (c-1): 7 parts

[0221] • Photopolymerization initiator APO(c-2): 3 parts

[0222] • Butyl acetate (d1-1): 2.8 parts

[0223] • Dimethyl carbonate (DMC) (d1-2): 35 parts

[0224] Methyl isobutyl ketone (MIBK) (d1-3): 12.2 parts

[0225] · Methyl ethyl ketone (MEK) (d2-1): 40 parts

[0226] • Propylene glycol monomethyl ether (PGM) (d2-2): 10 parts

[0227] <Examples 2 to 31, Comparative Examples 1 to 9>

[0228] Except for changes in composition and dosage (parts by mass) as shown in Tables 1 to 3, the hard coating forming compositions of Examples 2 to 31 and Comparative Examples 1 to 9 were manufactured in the same manner as in Example 1.

[0229] [Table 1]

[0230]

[0231] [Table 2]

[0232]

[0233] [Table 3]

[0234]

[0235] The obtained hard coating composition was used to evaluate its leaching resistance, pencil hardness, adhesion, and warpage by the following methods. The results are shown in Tables 1 to 3.

[0236] [Resistance to leaching]

[0237] The composition for forming a hard coating, obtained by coating a 50 μm thick triacetyl cellulose film containing a UV blocker with a transmittance of 8% or higher at 380 nm using a bar coater No. 8, was subjected to a cumulative exposure of 400 mJ / cm under irradiation with a high-pressure mercury lamp with a power of 80 W / cm. 2 Ultraviolet light is used to harden the coating layer, resulting in a hard coating film with a thickness of 5 μm to 6 μm for evaluating leaching resistance. The obtained hard coating film is then cut into test films with a length of 100 mm and a width of 50 mm to form test films.

[0238] The test membrane was immersed in a 9 wt% sodium hydroxide aqueous solution heated to 50°C for 5 minutes, the removed test membrane was washed with water, and dried in a box oven at 100°C for 2 minutes.

[0239] Measure the transmittance (ta) and transmittance (tc) shown below.

[0240] (ta): Transmittance of the hard coating film not immersed in sodium hydroxide aqueous solution at a wavelength of 380 nm.

[0241] (tc): Transmittance of the hard coating film at a wavelength of 380 nm after immersion in an aqueous sodium hydroxide solution, washing with water, and drying.

[0242] Based on the obtained (ta) and (tc), calculate (tc) - (ta), and evaluate the leaching resistance according to the following criteria. Furthermore, Comparative Example 5, which did not contain a UV stopper, cannot be evaluated for leaching resistance and is therefore set to "-".

[0243] ○:(tc)-(ta)≦1% (Good)

[0244] △: 1% < (tc) - (ta) ≦ 2% (practically sound)

[0245] ×: 2% < (tc) - (ta) (Not applicable)

[0246] [Pencil Hardness]

[0247] Similar to [Dissolution Resistance], a hard coating film for evaluating pencil hardness was obtained. The pencil hardness of the obtained hard coating film was determined using pencils of different hardnesses according to the test method of Japanese Industrial Standards (JIS) K5400 (1990).

[0248] ◎: Pencil hardness is 3H or higher (excellent)

[0249] ○: The pencil hardness is H to 2H (good).

[0250] △: The pencil's hardness is F (no problem in practical use).

[0251] ×: Pencil hardness below HB (not practical)

[0252] [Seamlessness]

[0253] A hard coating film for evaluating adhesion was obtained in the same manner as for [resistance to leaching]. The hard coating film was attached to a glass plate with the opposite side of the hard coating layer through an adhesive layer of approximately 20 μm thickness. The surface of the hard coating was then subjected to a checkerboard peel test according to JIS K5400, and the results were judged based on the following indicators.

[0254] ◎: Number of stripped items 0 / 100 (Excellent)

[0255] ○: Number of peeled items: 1-5 / 100 (Good)

[0256] △: Number of peels: 6-20 / 100 (practically feasible)

[0257] ×: Number of peels: 21-100 / 100 (Not usable)

[0258] [Warpage Test]

[0259] A hard coating for warpage testing is obtained in the same manner as [Dissolution Resistance].

[0260] The obtained hard coating film was cut into 100mm long and 50mm wide pieces and used as test films. The films were placed in a constant temperature and humidity chamber at 22℃ and 50%RH for 6 hours.

[0261] Place the test membrane on a horizontal surface, and use a micrometer to measure the distance between the two ends and the center of the long side at three locations, and calculate the average value.

[0262] ◎: 40mm or more (Excellent)

[0263] ○: 30mm or more but less than 40mm (Good)

[0264] △: 10mm or more but less than 30mm (no practical problems)

[0265] ×: Cylindrical or less than 10mm (not practical)

[0266] As shown in Tables 1 to 3, by using the active energy line curing composition for hard coating forming of the present invention, a hard coating film can be provided that has high UV cutoff, reduces the dissolution of UV cutoff agents in the saponification process, reduces the UV cutoff of the coating film and prevents contamination of the saponification treatment solution, improves the efficiency of display manufacturing process due to low curling, and has damage prevention properties in display manufacturing process due to high hard coating properties.

Claims

1. An active energy line curing composition for forming a hard coating, which is a composition for forming a hard coating on a triacetyl cellulose membrane. It contains: active energy line hardening component (A), ultraviolet blocking agent (B), photopolymerization initiator (C), and solvent (D). The active energy line hardening component (A) contains The polyfunctional urethane (meth)acrylate (a1) having 6 or more (meth)acryloyl groups and a urate ring skeleton, all polyfunctional urethane (meth)acrylate (a2) having 4 or more and 15 (meth)acryloyl groups and a weight average molecular weight of 500 to 15,000, other than the polyfunctional urethane (meth)acrylate (a1), and other polyfunctional (meth)acrylates (a3). The mass ratio (a1) / (a2) of the polyfunctional urethane (meth)acrylate (a1) to the polyfunctional urethane (meth)acrylate (a2) contained in the hardening component (A) of the active energy line is 20 / 80 to 80 / 20. Solvent (D) includes solvent (d1) and solvent (d2) other than solvent (d1) that satisfies the following formula (1) selected from the group consisting of dimethyl carbonate, ethyl acetate, n-butyl acetate, acetone, methyl ethyl ketone and 1,3-dioxolane. Equation (1) [(X2) / (X1)]≧0.25 (X1): Haze value of an 80 μm thick triacetylcellulose membrane without added solvent. (X2): Haze value of a triacetylcellulose membrane with a thickness of 80 μm after solvent addition and drying.

2. A hard coating film having a hard coating formed on a triacetylcellulose membrane by an active energy line curing composition for hard coating formation as described in claim 1.

3. The hard coating film according to claim 2, wherein the transmittance (ta) at a wavelength of 380 nm is less than 4%, and the transmittance (tb) at a wavelength of 420 nm is more than 70%.

4. The hard coating according to claim 3, wherein the following formula (2) is satisfied. Formula (2) (tc)-(ta)≦1% (ta): Transmittance of the hard coating film not impregnated with sodium hydroxide aqueous solution at a wavelength of 380 nm. (tc): The transmittance of the hard coating film at a wavelength of 380 nm after immersion in an aqueous sodium hydroxide solution, washing with water, and drying.

5. A laminate having a hard coating and a circular polarizing functional layer as described in any one of claims 2 to 4.

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