Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/046—Forming abrasion-resistant coatings; Forming surface-hardening coatings
• • G—PHYSICS
  • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
  • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
  • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F222/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides, or nitriles thereof
  • C08F222/36—Amides or imides
  • C08F222/40—Imides, e.g. cyclic imides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F265/00—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
  • C08F265/04—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00 on to polymers of esters
  • C08F265/06—Polymerisation of acrylate or methacrylate esters on to polymers thereof

Definitions

• the present disclosure relates to a transparent resin substrate for flexible displays and a hard coat film having a hard coat layer on at least one main surface of the transparent resin substrate.
• plastic films are required to have high heat resistance, high dimensional stability at high temperatures, high mechanical strength, and the like.
• curved displays and foldable flexible displays foldable displays, bendable displays, etc.
• the plastic film used for cover windows and the like has excellent transparency in addition to the above properties. and flexibility (flexibility) are required.
• Patent Literature 1 discloses an optical film containing a polyimide-based polymer used for a front plate of a flexible device member.
• the transparent polyimide film has excellent heat resistance and mechanical strength, it has a problem that the width of the molding processing is narrow due to the high heat resistance, and a problem that the material cost is high, which pushes up the price of the entire display.
• Patent Document 2 discloses a hard coat film for a surface protection film of a flexible display using a polyester film. Polyester film has excellent mechanical strength and dimensional stability, and the material cost is low. .
• acrylic resins have high transparency and excellent optical properties, they are applied to various display applications such as liquid crystal display devices and organic EL display devices.
• Patent Document 3 relates to a hard coat film in which an acrylic hard coat layer is applied to a protective resin layer made of an acrylic resin for use as a front plate. There is disclosed a technique for eliminating unevenness.
• Patent Document 4 describes that an optical film such as a polarizer protective film can be obtained with high toughness by containing a predetermined acrylic resin and rubber particles.
• the present disclosure provides a transparent resin substrate that is excellent in optical properties and flexibility (bendability) and has excellent image quality (image quality) even under conditions of use where external force is repeatedly applied, and the transparent resin substrate.
• An object of the present invention is to provide a hard coat film having excellent flexibility, in which a hard coat layer is formed on at least one main surface of the film.
• a transparent resin substrate for a flexible display including a (meth)acrylic resin having a weight average molecular weight of 200,000 or more, A transparent resin substrate having a glass transition temperature of 110° C. or higher and a photoelastic constant of ⁇ 5.0 ⁇ 10 ⁇ 12 to 5.0 ⁇ 10 ⁇ 12 Pa ⁇ 1 .
• ⁇ 2> The transparent resin substrate according to ⁇ 1>, which has an orientation birefringence of ⁇ 2.0 ⁇ 10 ⁇ 4 to 2.0 ⁇ 10 ⁇ 4 .
• the (meth)acrylic resin comprises 30 to 100% by weight of methyl methacrylate units and 0 to 70% by weight of other monomer units copolymerizable with the methyl methacrylate units as structural units (meth)
• the other monomer unit is an N-substituted maleimide-based monomer unit, a methacrylate ester unit in which the ester moiety is a primary or secondary hydrocarbon group having 2 to 20 carbon atoms or an aromatic hydrocarbon group; methacrylic acid ester units in which the ester portion is a saturated hydrocarbon group having 7 to 16 carbon atoms and having a condensed ring structure, methacrylic acid ester units in which the ester portion is a linear or branched group containing an ether bond, and styrene
• the transparent resin substrate according to ⁇ 4> which is at least one selected from the group consisting of system monomer units.
• the (meth)acrylic resin comprises crosslinked (meth)acrylic polymer particles (a) having an average particle diameter of 150 nm or less and a glass transition temperature of ⁇ 10° C. or less, and a weight average molecular weight of 200,000 or more.
• the transparent resin substrate according to any one of ⁇ 1> to ⁇ 4>.
• ⁇ 7> The transparent resin substrate according to any one of ⁇ 1> to ⁇ 6>, which is produced by a solution casting method.
• ⁇ 8> The transparent resin substrate according to any one of ⁇ 1> to ⁇ 7>, which has a haze of less than 1.5%.
• ⁇ 9> The transparent resin substrate according to any one of ⁇ 1> to ⁇ 8>, wherein a hard coat layer is laminated on at least one main surface.
• a hard coat film comprising a hard coat layer on at least one main surface of the transparent resin substrate according to any one of ⁇ 1> to ⁇ 9>.
• an easy-adhesion layer made of an easy-adhesive composition containing a polyurethane resin having a carboxyl group and a trifunctional or higher polyfunctional epoxy-based cross-linking agent, The hard coat film according to ⁇ 10>.
• the polyorganosiloxane compound is a condensate of a silane compound represented by the following formula (1), the condensate has a weight average molecular weight of 500 to 20000, The molar ratio of the structural unit represented by the following formula (3) and the structural unit represented by the following formula (4) contained in the condensate ([structural unit represented by formula (3)] / [formula ( The hard coat film according to ⁇ 12>, wherein the structural unit represented by 4)]) is less than 5.
• R 1 represents an alkylene group having 2 to 16 carbon atoms
• R 2 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms
• R 3 represents a hydrogen atom, and a an alkyl group, an aryl group having 6 to 25 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms
• x is 2 or 3
• Y is a glycidyloxy group represented by the following formula (2-1), or It represents an alicyclic epoxy group represented by the following formula (2-2).
• * indicates the bonding position with R 1.
• R 1 and Y have the same definitions as in formula (1) above.
• R 1 and Y have the same definitions as in formula (1) above.
• Z is a hydrogen atom, an alkoxy group having an alkyl moiety having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, a carbon represents an aryl group having 6 to 25 carbon atoms or an aralkyl group having 7 to 12 carbon atoms.
• ⁇ 14> The hard coat film according to any one of ⁇ 10> to ⁇ 13>, which has a total thickness of 40 to 500 ⁇ m and a total light transmittance of 80% or more.
• ⁇ 15> The hard coat film according to any one of ⁇ 10> to ⁇ 14>, wherein the hard coat layer has a thickness of 10 to 100 ⁇ m.
• a flexible display comprising the transparent resin substrate according to any one of ⁇ 1> to ⁇ 9>.
• a transparent resin base material for a flexible display that has excellent optical properties and flexibility (flexibility) and can reproduce excellent image quality even when deformed by an external force. Further, by forming a hard coat layer on at least one main surface of the transparent resin substrate, it is possible to provide a hard coat film having excellent flexibility. Such transparent resin substrates and hard coat films are suitably used as films for flexible displays.
• the present disclosure relates to a transparent resin substrate (transparent resin film) for flexible displays and a hard coat film having a hard coat layer on at least one main surface of the transparent resin substrate.
• the flexible display is a continuous display that has a structure that can be deformed according to the application, and a curved display with a curved shape; displays; rollable or slidable displays that are roll-up displays; and the like. These displays can be suitably used as organic EL displays with flexible light-emitting layers.
• the transparent resin substrate of the present disclosure contains a (meth)acrylic resin having a weight average molecular weight of 200,000 or more.
• the weight average molecular weight of the (meth)acrylic resin is preferably 400,000 or more, more preferably 500,000 or more, still more preferably 1,000,000 or more, and particularly preferably 1,500,000 or more. , is more than 2 million.
• the weight average molecular weight of the (meth)acrylic resin is preferably 5,000,000 or less, more preferably 3,500,000 or less, from the viewpoint of moldability.
• the weight-average molecular weight of the (meth)acrylic resin is within the above preferred range, the toughness and flexibility (flexibility) of the base material are increased, and a tough base material that is resistant to deformation can be obtained. can.
• the weight average molecular weight of the (meth)acrylic resin is less than 200,000, the base material is not immediately fragile and fragile, but the high toughness and flexibility (flexibility) required for flexible display applications is difficult to obtain.
• the ratio of the (meth)acrylic resin having a weight average molecular weight of 200,000 or more is preferably 50% by weight or more, more preferably more than 50% by weight, relative to 100% by weight of the transparent resin substrate. , more preferably 70% by weight or more, particularly preferably 80% by weight or more, extremely preferably 90% by weight or more, and most preferably 95% by weight or more.
• the upper limit of the proportion of the (meth)acrylic resin may be 100% by weight, 99% by weight, 98% by weight, or 97% by weight.
• the method for producing the transparent resin base material of the present disclosure is not particularly limited, but from the viewpoint of molding a high-molecular-weight (meth)acrylic resin, it is preferably produced by a solution casting method.
• Transparent resin substrates made of common (meth)acrylic resins are often produced by melt extrusion, but the transparent resin substrate of the present disclosure has a high molecular weight. Viscosity increases and molding load increases.
• the (meth)acrylic resin and, if necessary, other components are mixed with a solvent that dissolves the (meth)acrylic resin well, a so-called good solvent, and each component is dissolved or dispersed in the solvent to prepare a dope.
• the dope may be prepared by dissolving or dispersing each component in a solvent simultaneously or sequentially, or a plurality of dopes are prepared by dissolving or dispersing at least one component in a solvent, and they are mixed. You may make it
• the step of dissolving or dispersing can be carried out by appropriately adjusting the temperature and pressure. After the above steps, the obtained dope can be filtered or defoamed.
• the prepared dope is sent to a pressurized die by a liquid-sending pump, and the dope is sent from the slit of the pressurized die onto the surface (mirror surface) of a metal or synthetic resin support (endless belt, drum, etc.). It is cast to form a dope film (cast film).
• the formed doped film is then heated on the support to evaporate the solvent and form a film.
• the conditions for evaporating the solvent can be appropriately determined according to the boiling point of the solvent used.
• the film thus obtained is peeled off from the support surface. After that, the obtained film may be appropriately subjected to a drying process, a heating process, a stretching process, and the like.
• the type of good solvent is not particularly limited as long as it dissolves the (meth)acrylic resin.
• Examples include chlorine-based organic solvents such as methylene chloride; chlorinated organic solvents; and the like. Among them, methylene chloride is preferable because the (meth)acrylic resin can be dissolved satisfactorily.
• Alcohol which is a poor solvent, can also be added to the dope together with the good solvent.
• alcohols linear or branched aliphatic alcohols having 1 to 4 carbon atoms can be used. Among them, ethanol and/or methanol are preferred. By adding such alcohols, the drying efficiency of the dope is improved, and the evaporating alcohols create a large number of voids in the film, making the film more hydrophobic, resulting in excellent peelability from the support.
• a transparent resin base material can be obtained.
• the amount added is preferably 1 to 25% by weight, more preferably 2 to 20% by weight, and more preferably 3 to 15% by weight, based on the total amount of the solvent added to the dope. It is even more preferable to have
• the glass transition temperature of the transparent resin base material of the present disclosure is 110° C. from the viewpoint of improving the dimensional stability of the base material in the usage environment and preventing deformation due to heat generated in the processing process during module assembly. is preferably 115°C or higher, more preferably 115°C or higher, even more preferably 120°C or higher, particularly preferably 123°C or higher, extremely preferably 124°C or higher, and 125°C or higher. is most preferred.
• Birefringence is one of the important optical properties that must be taken into account when optical members are manufactured using optical resins.
• Polymers are molecules in which ellipsoids with direction-dependent refractive indices are linked together. Therefore, when a polymer is deformed to orient its molecular chains, the refractive index differs between the direction of orientation and the direction perpendicular to it. birefringence.
• a state in which there is birefringence is a state in which light travels at different speeds depending on the direction of the plane of vibration when light passes through a substance, and is optically anisotropic.
• optical components such as liquid crystal display devices, optical disc devices, and projection screens
• the presence of birefringent films, lenses, etc. in the optical path affects image quality and signal reading performance.
• an optical member made of an optical resin made of a high-quality material is desirable.
• a smaller birefringence is desirable from the viewpoint of improving image quality and light extraction efficiency.
• the birefringence exhibited by optical resins includes "orientation birefringence", which is mainly caused by the orientation of the main chain of the polymer, and "photoelastic birefringence”, which is caused by stress. There is.
• the signs of orientation birefringence and photoelastic birefringence are derived from the chemical structure of the polymer and are inherent properties of each polymer.
• orientation birefringence is birefringence that is generally expressed by the orientation of the main chain of a chain polymer (polymer chain). It occurs in a process that involves material flow, such as a stretching process, or an injection molding process for manufacturing an optical member, and it occurs when it remains fixed to the optical member.
• material flow such as a stretching process, or an injection molding process for manufacturing an optical member
• the orientation birefringence is positive. express.
• orientation birefringence is birefringence that occurs due to the orientation of polymer chains.
• the orientation birefringence in this specification refers to the orientation of a film obtained by preheating for 5 minutes under conditions of +10 ° C. with respect to the glass transition temperature and then uniaxially stretching 1.5 times at a fixed width at a speed of 100 mm / min. Defined as birefringence.
• the orientation birefringence of the transparent resin substrate of the present disclosure is preferably ⁇ 2.0 ⁇ 10 ⁇ 4 to 2.0 ⁇ 10 ⁇ 4 from the viewpoint of improving display image quality and light extraction efficiency, and ⁇ It is more preferably 1.5 ⁇ 10 ⁇ 4 to 1.5 ⁇ 10 ⁇ 4 , further preferably ⁇ 1.0 ⁇ 10 ⁇ 4 to 1.0 ⁇ 10 ⁇ 4 , and ⁇ 0.8 ⁇ 10 ⁇ 4 to 0.8 ⁇ 10 ⁇ 4 is particularly preferred, ⁇ 0.5 ⁇ 10 ⁇ 4 to 0.5 ⁇ 10 ⁇ 4 is particularly preferred, and ⁇ 0.2 ⁇ 10 ⁇ 4 to 0.2 ⁇ 10 ⁇ 4 is most preferred.
• Photoelastic birefringence is birefringence caused by elastic deformation (strain) of polymers.
• strain elastic deformation
• an optical member using a polymer for example, elastic deformation (strain) occurs and remains in the material due to volumetric contraction that occurs when the polymer is cooled from around the glass transition temperature to a temperature below it. , which causes photoelastic birefringence.
• an optical member is used at a temperature below the glass transition temperature, such as the temperature of a general operating environment, the material is elastically deformed by the external force received while it is fixed to the device, and this results in photoelastic multiplication. cause refraction.
• Photoelastic birefringence is birefringence caused by elastic deformation (strain) of polymers in a polymer compact when stress is applied to the polymer compact.
• strain elastic deformation
• the photoelastic constant of the transparent resin substrate of the present disclosure is preferably ⁇ 5.0 ⁇ 10 ⁇ 12 to 5.0 ⁇ 10 ⁇ 12 Pa ⁇ 1 and ⁇ 3.0 ⁇ 10 ⁇ 12 to 3.0 ⁇ 10 ⁇ 12 Pa ⁇ 1 is more preferable, ⁇ 2.5 ⁇ 10 ⁇ 12 to 2.5 ⁇ 10 ⁇ 12 Pa ⁇ 1 is further preferable, and ⁇ 1.5 ⁇ 10 ⁇ 12 to 1 .5 ⁇ 10 ⁇ 12 Pa ⁇ 1 is more preferred, ⁇ 1.0 ⁇ 10 ⁇ 12 to 1.0 ⁇ 10 ⁇ 12 Pa ⁇ 1 is particularly preferred, and ⁇ 0.8 ⁇ 10 ⁇ 1 12 to 0.8 ⁇ 10 ⁇ 12 Pa ⁇ 1 is particularly preferred, ⁇ 0.5 ⁇ 10 ⁇ 12 to 0.5 ⁇ 10 ⁇ 12 Pa ⁇ 1 is particularly preferred, ⁇ 0.3 ⁇ Most preferably it is between 10 ⁇ 12 and 0.3 ⁇ 10 ⁇ 12 Pa ⁇ 1 .
• the photoelastic constant is within the above range, when the transparent resin substrate of the present disclosure is used as a film for a flexible display, when external force is generated due to various deformations such as bending, bending, folding, and winding. Even so, the resulting birefringence is extremely small, and there is no fear of the occurrence of retardation unevenness, deterioration of image quality and contrast in the periphery of the deformation, light leakage, and the like. The same is true when the film is deformed and stress is applied in a use environment such as high temperature and high humidity.
• orientation birefringence and photoelastic birefringence are derived from the chemical structure of the polymer (constituent monomer), and their signs are inherent properties of each polymer (constituent monomer).
• the transparent resin substrate of the present disclosure is required to have low photoelastic birefringence, and both orientation birefringence and photoelastic birefringence are desired to be low.
• methyl methacrylate which is a constituent monomer of polymethyl methacrylate (PMMA), which is a representative (meth)acrylic resin, exhibits both orientation birefringence (intrinsic birefringence) and photoelastic birefringence with negative signs.
• Intrinsic birefringence refers to orientation birefringence in a state in which a polymer is completely oriented in one direction.
• N-phenylmaleimide and N-cyclohexylmaleimide which are N-substituted maleimide monomers
• benzyl methacrylate which is a methacrylate monomer having an aromatic hydrocarbon group
• orientation birefringence intrinsic birefringence
• Both photoelastic birefringences show a positive sign. Therefore, by combining these monomers by copolymerization and adjusting the introduction ratio, the orientation birefringence and photoelastic birefringence of opposite signs are canceled each other, and a polymer with both small orientation birefringence and photoelastic birefringence can be obtained. can be obtained.
• the optical design described above is the same for crosslinked polymer particles (graft copolymer of the second embodiment, polymer particles (I), etc., described later).
• monomers constituting a crosslinked polymer or a non-crosslinked polymer that is not graft-bonded to the crosslinked polymer monomers having orientation birefringence (intrinsic birefringence) and photoelastic birefringence with different signs are combined by copolymerization, By adjusting the introduction ratio, the orientation birefringence and the photoelastic birefringence of opposite signs are offset each other, making it possible to obtain crosslinked polymer particles having both small orientation birefringence and photoelastic birefringence.
• [Haze] Preferred aspects of haze in the transparent resin substrate of the present disclosure will be described.
• a transparent resin base material for a liquid crystal display device, an organic EL display device, etc. from the viewpoint of effectively utilizing the incident light from the light source unit, it is desirable to use a base material with high transparency and low haze. Needless to say, it is preferable.
• the haze of the transparent resin base material used has a more important meaning in displays, such as organic EL displays, which aim for high contrast in light and dark areas (black and white areas).
• organic EL display device with no backlight and equipped with light-emitting elements is operated so that the elements do not emit light at all when reproducing black. It has excellent black reproducibility and can provide high-contrast images.
• organic EL display devices are superior in contrast to liquid crystal display devices, but in recent years, as typified by the HDR (High Dynamic Range) standard, there is a demand for further improvement in contrast.
• HDR High Dynamic Range
• an organic EL display device for a foldable display has a plurality of functional film layers such as a cover window, a cover window protective film, a shock absorbing layer, and a back film.
• a plurality of functional film layers are laminated on the light source unit in this way, if the functional film layers are affected by light scattering, the influence of interference between adjacent light emitting elements cannot be ignored.
• the functional film layer has a high haze and has a scattering source, when light incident from a certain light-emitting element passes through the functional film layer, light scattering or diffusion occurs inside or on the surface of the layer, causing non-light-emitting adjacent layers.
• the functional film layer is required to have a low haze.
• the materials constituting the functional film layer should be composed of substances with the same refractive index as much as possible. It is desirable that
• the haze of the transparent resin base material of the present disclosure can be reduced by reducing the influence of light scattering as much as possible using the above measures as examples.
• the haze of the transparent resin substrate of the present disclosure is preferably less than 1.5%, more preferably less than 1.2%, even more preferably less than 1.0%, and 0.8%. It is particularly preferred that it is less than 0.5%, very preferably less than 0.5% and most preferably less than 0.3%.
• a hard coat film having a hard coat layer on at least one main surface of the transparent resin base material, or an easy-adhesion layer provided between the transparent resin base material and the hard coat layer is also important to consider the influence of light scattering in a hard coat film with an adhesive layer. In these films, the influence of light scattering between various layers such as the transparent resin base material, the hard coat layer, and the easy adhesion layer can be considered. The key to reducing the effects of scattering is to have the layers adhere tightly to each other so that no voids are formed between them. As described above, reducing the influence of scattering not only on the transparent resin base material but also on the hard coat layer and the easy-adhesion layer provided is considered to be the design for increasing the contrast when viewed as a whole display. I can say.
• the retardation is an index value calculated based on birefringence, and the in-plane retardation (Re) and the thickness direction retardation (Rth) can be calculated by the following formulas. In an ideal compact that is completely optically isotropic in three-dimensional directions, both the in-plane retardation (Re) and the thickness direction retardation (Rth) are zero.
• nx, ny, and nz are the in-plane elongation direction (orientation direction of the polymer chain) as the X axis, the direction perpendicular to the X axis as the Y axis, and the thickness direction of the substrate as the Z axis. represents the refractive index in each axial direction. Also, d represents the thickness of the substrate, and nx-ny represents the orientation birefringence. Note that the MD direction of the base material is the X axis, but in the case of a stretched base material, the stretching direction is the X axis.
• the optical isotropy is small.
• the optical isotropy in the thickness direction is also preferably small. More specifically, the absolute value of the in-plane retardation is preferably 10.0 nm or less, more preferably 5.0 nm or less, and even more preferably 3.0 nm or less.
• the absolute value of the thickness direction retardation is preferably 20.0 nm or less, more preferably 10.0 nm or less, and even more preferably 5.0 nm or less.
• a transparent resin substrate having such a retardation can be suitably used as a substrate film for a flexible display such as an organic EL display device.
• (Meth)acrylic resin of the first aspect As a first aspect of the (meth)acrylic resin contained in the transparent resin substrate of the present disclosure, 30 to 100% by weight of methyl methacrylate units and other monomers copolymerizable with the methyl methacrylate units A (meth)acrylic resin having a unit of 0 to 70% by weight as a structural unit can be mentioned.
• methyl methacrylate unit is a structural unit represented by the following formula.
• the (meth)acrylic resin of the first aspect preferably has a methyl methacrylate unit content of 50% by weight or more, more preferably 60% by weight or more, from the viewpoint of appearance, weather resistance, etc. , more preferably 70% by weight or more, and particularly preferably 80% by weight or more.
• the (meth)acrylic resin of the first aspect preferably has a methyl methacrylate unit content of 99.9% by weight or less, preferably 99% by weight or less, from the viewpoint of optical properties, heat resistance, and the like. It is more preferably 97% by weight or less, and particularly preferably 95% by weight or less.
• Other monomer units that can be copolymerized with methyl methacrylate units include N-substituted maleimide monomer units, primary or secondary hydrocarbon groups having 2 to 20 carbon atoms in the ester moiety, or aromatic hydrocarbon groups.
• a methacrylic acid ester unit that is a hydrogen group a methacrylic acid ester unit that is a saturated hydrocarbon group having 7 to 16 carbon atoms in which the ester portion has a condensed ring structure, a linear or branched group in which the ester portion contains an ether bond and at least one selected from the group consisting of methacrylate units and styrene-based monomer units.
• N-substituted maleimide-based monomer units examples include N-phenylmaleimide units, N-benzylmaleimide units, N-cyclohexylmaleimide units, N-methylmaleimide units, and the like.
• maleimide-based monomer units having a cyclic substituent on the nitrogen atom ie, N-phenylmaleimide units, N-benzylmaleimide units, and N-cyclohexylmaleimide units are preferred.
• methacrylic acid ester units in which the ester moiety is a primary or secondary hydrocarbon group having 2 to 20 carbon atoms or an aromatic hydrocarbon group examples include ethyl methacrylate units, propyl methacrylate units, methacrylic acid n -butyl unit, hexyl methacrylate unit, cyclohexyl methacrylate unit, 2-ethylhexyl methacrylate unit, octyl methacrylate unit, stearyl methacrylate unit, phenyl methacrylate unit, benzyl methacrylate unit and the like.
• ethyl methacrylate units ethyl methacrylate units, n-butyl methacrylate units, cyclohexyl methacrylate units, 2-ethylhexyl methacrylate units, phenyl methacrylate units, and benzyl methacrylate units are preferred.
• methacrylic acid ester units in which the ester moiety is a saturated hydrocarbon group having 7 to 16 carbon atoms and having a condensed ring structure include a dicyclopentanyl methacrylate unit and an isobornyl methacrylate unit.
• the saturated hydrocarbon group preferably has 8 to 14 carbon atoms, more preferably 9 to 12 carbon atoms.
• the condensed ring structure is preferably a structure in which two five-membered rings are condensed by three consecutive carbon atoms.
• Examples of the methacrylic acid ester unit whose ester moiety is a linear or branched group containing an ether bond include a 2-methoxyethyl methacrylate unit.
• styrene-based monomer units examples include styrene units, ⁇ -methylstyrene units, monochlorostyrene units, and dichlorostyrene units. Among them, styrene units are preferred.
• (Meth)acrylic resin of the second aspect As a second aspect of the (meth)acrylic resin contained in the transparent resin base material of the present disclosure, a crosslinked (meth)acrylic polymer having an average particle diameter of 150 nm or less and a glass transition temperature of ⁇ 10° C.
• the crosslinked (meth)acrylic polymer graft-bonded to the polymer particles (a) and out of the total of the crosslinked (meth)acrylic polymer particles (a) and the non-crosslinked methacrylic polymer component (b) Graft copolymers in which the proportion of particles (a) is 1% by weight or more and less than 50% by weight (hereinafter also referred to as "specific graft copolymers") can be mentioned.
• the (meth)acrylic resin contained in the transparent resin base material of the present disclosure is a specific graft copolymer
• a high-strength transparent resin base material is formed even if the resin component is only the specific graft copolymer. be able to.
• a transparent resin base material with low haze can be easily formed.
• the specific graft copolymer has excellent storage stability despite containing a rubber component, when the dope is prepared by dissolving it in a solvent in the case of production by the solution casting method, the dope does not It also has the advantage of being less cloudy. As a result, the haze of the transparent resin substrate produced by the solution casting method can be reduced.
• the specific graft copolymer contains crosslinked (meth)acrylic polymer particles (a) and a non-crosslinked methacrylic polymer component (b). Since the crosslinked (meth)acrylic polymer particles (a) are a rubber component, they can contribute to improvement in strength. Also, excellent heat resistance can be achieved by the non-crosslinked methacrylic polymer component (b). In comparison with a conventional system in which a core-shell type graft copolymer is blended with a (meth)acrylic resin, the crosslinked (meth)acrylic polymer particles (a) are the core-shell type graft copolymer. It corresponds to the rubber component of the core, and the non-crosslinked methacrylic polymer component (b) corresponds to the (meth)acrylic resin of the matrix.
• At least part of the non-crosslinked methacrylic polymer component (b) is graft-bonded to the crosslinked (meth)acrylic polymer particles (a).
• the graft bond can be realized by producing a graft copolymer by emulsion polymerization as described later. Due to this production method, the specific graft copolymer may also contain a non-crosslinked methacrylic polymer component (b) that is not graft-bonded to the crosslinked (meth)acrylic polymer particles (a).
• the specific graft copolymer may have a structure in which crosslinked (meth)acrylic polymer particles (a) having a small particle size are dispersed in a non-crosslinked methacrylic polymer component (b) having a high molecular weight, Therefore, the aggregation of the crosslinked (meth)acrylic polymer particles (a) in the specific graft copolymer hardly progresses. As a result, the stability is improved both when the specific graft copolymer is stored in a powder form and when it is stored as a dope dissolved in a solvent. In addition, since aggregation of the crosslinked (meth)acrylic polymer particles (a) is suppressed, the specific graft copolymer also has the advantage of being easily dissolved in a solvent.
• the crosslinked (meth)acrylic polymer particles (a) are (meth)acrylic rubber particles.
• the specific graft copolymer can achieve high strength, for example, when used as a transparent resin substrate.
• the crosslinked (meth)acrylic polymer particles (a) have a relatively small particle size, specifically an average particle size of 150 nm or less.
• a relatively small particle size specifically an average particle size of 150 nm or less.
• crosslinked (meth)acrylic polymer particles having such a small particle size a low haze can be achieved when the specific graft copolymer is formed into a film, for example.
• the refractive index of the crosslinked (meth)acrylic polymer particles (a) and the refractive index of the non-crosslinked methacrylic polymer component (b) are reduced. No need to match.
• the average particle size of the crosslinked (meth)acrylic polymer particles (a) is preferably 130 nm or less, more preferably 120 nm or less, and further preferably 110 nm or less. It is preferably 100 nm or less, and particularly preferably 100 nm or less.
• the lower limit of the average particle size is not particularly limited, it is preferably 30 nm or more, more preferably 50 nm or more, from the viewpoint of the strength of the transparent resin substrate or the ease of production of the specific graft copolymer. It is more preferably 60 nm or more.
• the average particle size is the volume average particle size and can be measured by a known particle size measurement method.
• the crosslinked (meth)acrylic polymer particles (a) have a glass transition temperature of -10°C or lower.
• the glass transition temperature can be adjusted by the type and ratio of the monomers constituting the crosslinked (meth)acrylic polymer particles (a).
• the glass transition temperature of the crosslinked (meth)acrylic polymer particles (a) is preferably ⁇ 20° C. or lower, more preferably ⁇ 30° C. or lower, further preferably ⁇ 40° C. or lower, -45°C or lower is particularly preferred.
• the lower limit of the glass transition temperature is not particularly limited. is particularly preferred, and -70°C or higher is extremely preferred.
• the glass transition temperature of the crosslinked (meth)acrylic polymer particles (a) is calculated using Fox's formula using the values described in Polymer Handbook [Polymer Hand Book (J. Brandrup, Interscience 1989)]. (For example, the glass transition temperature of polyn-butyl acrylate is ⁇ 54° C.).
• the crosslinked (meth)acrylic polymer particles (a) are made from a crosslinked (meth)acrylic polymer obtained by polymerizing a monomer component containing a (meth)acrylic monomer and a polyfunctional monomer. It is the particles that are formed.
• the monomer components other than the polyfunctional monomers contain acrylic monomers and/or methacrylic monomers, and preferably contain at least acrylic monomers.
• an acrylic acid alkyl ester having an alkyl portion having 1 to 8 carbon atoms is preferable.
• Specific examples include ethyl acrylate, n-butyl acrylate, n-octyl acrylate, and 2-ethylhexyl acrylate. Only one type of alkyl acrylate may be used, or two or more types may be used in combination. Among them, n-butyl acrylate is preferred.
• An arbitrary methacrylic monomer that can be contained in the crosslinked (meth)acrylic polymer particles (a) is preferably a methacrylic acid alkyl ester in which the alkyl moiety has 1 to 8 carbon atoms.
• Specific examples include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, and octyl methacrylate.
• Only one type of methacrylic acid alkyl ester may be used, or two or more types may be used in combination. Among them, methacrylic acid alkyl esters having 1 to 4 carbon atoms in the alkyl portion are preferred, and methyl methacrylate is particularly preferred.
• monomers other than the alkyl acrylates and alkyl methacrylates described above may be used.
• examples of such monomers include acrylic acid esters other than acrylic alkyl esters, methacrylic acid esters other than methacrylic acid alkyl esters, aromatic vinyl monomers, other copolymerizable vinyl monomers, and the like.
• examples of acrylates other than alkyl acrylates include phenyl acrylate, benzyl acrylate, cyclohexyl acrylate, and isobornyl acrylate.
• methacrylic acid esters other than methacrylic acid alkyl esters include phenyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, and isobornyl methacrylate.
• aromatic vinyl monomers include styrene, ⁇ -methylstyrene, chlorostyrene, and other styrene derivatives.
• other copolymerizable vinyl monomers include unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile; ⁇ , ⁇ -unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; and vinyl acetate.
• the monomer component constituting the crosslinked (meth)acrylic polymer particles (a) is, among the monomer components excluding polyfunctional monomers, acrylic acid ester (especially alkyl
• acrylic acid ester especially alkyl
• the content of acrylic acid alkyl ester having 1 to 8 carbon atoms per part is preferably 70% by weight or more, more preferably 80% by weight or more, and even more preferably 90% by weight or more. , 95% by weight or more.
• the crosslinked (meth)acrylic polymer particles (a) are formed by polymerizing the above monomer components in the presence of a polyfunctional monomer.
• Polyfunctional monomers also known as cross-linking agents or cross-linkable monomers, are compounds having two or more unsaturated bonds copolymerizable with (meth)acrylic monomers in one molecule. be. Specifically, allyl methacrylate, allyl acrylate, diallyl maleate, diallyl fumarate, diallyl itaconate, monoallyl maleate, monoallyl fumarate, butadiene, divinylbenzene, triallyl isocyanurate, alkylene glycol dimethacrylate, alkylene glycol A diacrylate etc. are mentioned. These may use only 1 type, and may use 2 or more types. Allyl methacrylate is preferred.
• the amount of the polyfunctional monomer used can be appropriately set from the viewpoint of strength. It may be about 0.1 to 5.0 parts by weight per 100 parts by weight (excluding the functional monomer). From the viewpoint of the strength of the specific graft copolymer, the amount of the polyfunctional monomer used is the monomer component constituting the crosslinked (meth)acrylic polymer particles (a) (however, the polyfunctional monomer excluding) 100 parts by weight, preferably 0.2 to 3.5 parts by weight, more preferably 0.2 to 3.0 parts by weight, 0.3 to 2.0 parts by weight and particularly preferably 0.4 to 1.5 parts by weight.
• Non-crosslinked methacrylic polymer component (b) The non-crosslinked methacrylic polymer component (b) is mainly composed of polymerized methacrylic monomers and does not have a crosslinked structure (that is, obtained by polymerization without using a polyfunctional monomer). It is a coalescence. At least part of the non-crosslinked methacrylic polymer component (b) is graft-bonded to the crosslinked (meth)acrylic polymer particles (a), whereby the crosslinked (meth)acrylic polymer particles (a) becomes less likely to agglomerate. As a result, the storage stability of the specific graft copolymer is improved, and low haze can be achieved when used as a transparent resin substrate.
• the non-crosslinked methacrylic polymer component (b) is a polymer with a high molecular weight, and specifically has a weight average molecular weight of 200,000 or more. Since the non-crosslinked methacrylic polymer component (b) has a high molecular weight, the transparent resin base material can achieve high heat resistance, and when used as a base material for a flexible display, it exhibits excellent flexibility. Flexibility (flexibility) can be obtained.
• the weight average molecular weight of the non-crosslinked methacrylic polymer component (b) is preferably 500,000 or more, more preferably 1,000,000 or more, further preferably 1,500,000 or more, and 2,000,000 or more. is particularly preferred.
• the weight average molecular weight of the non-crosslinked methacrylic polymer component (b) is preferably 5,000,000 or less, more preferably 3,500,000 or less, from the viewpoint of moldability.
• the transparent resin substrate has high toughness and flexibility (flexibility), is resistant to deformation, A tough base material can be obtained.
• the weight average molecular weight of the non-crosslinked methacrylic polymer component (b) is less than 200,000, the base material does not immediately become brittle and fragile, but the high toughness and flexibility required for flexible displays (flexibility) becomes difficult to obtain.
• the glass transition temperature of the non-crosslinked methacrylic polymer component (b) is preferably 115°C or higher, more preferably 118°C or higher, and 120°C or higher. is more preferable.
• the upper limit of the glass transition temperature is not particularly limited, it may be, for example, 160° C. or lower, or 150° C. or lower.
• the glass transition temperature can be controlled by adjusting the types and proportions of the monomers constituting the non-crosslinked methacrylic polymer component (b).
• the glass transition temperature of the non-crosslinked methacrylic polymer component (b) is calculated using the Fox formula using the values described in Polymer Handbook [Polymer Hand Book (J. Brandrup, Interscience 1989)]. (eg, polymethyl methacrylate has a glass transition temperature of 105° C.).
• the non-crosslinked methacrylic polymer component (b) is a polymer mainly composed of methacrylic monomer units.
• the methacrylic monomer unit is preferably a methyl methacrylate unit.
• the content of methyl methacrylate units in the monomer components constituting the non-crosslinked methacrylic polymer component (b) is preferably 70 to 99% by weight. This makes it possible to improve the heat resistance and more easily form a film by the solution casting method.
• the content of methyl methacrylate units is more preferably 75 to 98% by weight, even more preferably 80 to 97% by weight, particularly preferably 85 to 96% by weight, and 88 to 95% by weight. is highly preferred, and 90 to 95% by weight is most preferred.
• the same material as the "drying accelerating comonomer unit" in the first aspect can be used as the monomer unit other than the methyl methacrylate unit.
• the content of the drying-promoting comonomer unit is preferably 1 to 30% by weight, more preferably 2 to 25% by weight. More preferably, 3 to 20% by weight is even more preferable, 4 to 18% by weight is particularly preferable, 4 to 15% by weight is particularly preferable, and 4 to 12% by weight is extremely preferable. , 5 to 10% by weight.
• the content of drying-promoting comonomer units means that the total of all the drying-promoting comonomer units contained constitutes the non-crosslinked methacrylic polymer component (b). It refers to the proportion in the monomer component. With such a content, the volatilization rate of the solvent in the solution casting method can be increased while the specific graft copolymer has excellent heat resistance.
• the content of each unit can be determined by proton nuclear magnetic resonance spectroscopy.
• the non-crosslinked methacrylic polymer component (b) may be a copolymer that does not contain other comonomer units that do not correspond to drying-accelerating comonomer units, or may contain other comonomer units that do not correspond to drying-accelerating comonomer units.
• comonomers include, for example, glycidyl methacrylate, epoxycyclohexylmethyl methacrylate, dimethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2,2,2-trifluoroethyl methacrylate, 2 , 2,2-trichloroethyl methacrylate, methacrylamide, N-methylol-methacrylamide and other methacrylic acid esters; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylic acid Acrylic acid esters such as benzyl, octyl acrylate, glycidyl acrylate, epoxycyclohexylmethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, acrylamide, N-methylol
• the ratio of such other comonomer units to the total monomer components constituting the non-crosslinked methacrylic polymer component (b) is preferably 10% by weight or less, more preferably 8% by weight or less. It is preferably 5% by weight or less, and more preferably 5% by weight or less.
• the ratio of the crosslinked (meth)acrylic polymer particles (a) to the total of the crosslinked (meth)acrylic polymer particles (a) and the non-crosslinked methacrylic polymer component (b) is 1% by weight or more and less than 50% by weight, and the proportion of the non-crosslinked methacrylic polymer component (b) is more than 50% by weight and 99% by weight or less.
• the specific graft copolymer contains the non-crosslinked methacrylic polymer component (b) in such a high proportion, the crosslinked (meth)acrylic polymer particles (a) are less likely to aggregate, resulting in high strength and low A haze film can be formed, and the storage stability of the specific graft copolymer or its dope can be improved.
• crosslinked (meth)acrylic polymer particles (a) and non-crosslinked methacrylic polymer particles (a) The ratio of the crosslinked (meth)acrylic polymer particles (a) to the total amount of the component (b) is preferably 3 to 45% by weight, more preferably 4 to 40% by weight. More preferably ⁇ 35% by weight, particularly preferably 6 to 30% by weight.
• the crosslinked ( The proportion of the meth)acrylic polymer particles (a) is preferably 5% by weight or more, more preferably 6% by weight or more, and even more preferably 7% by weight or more.
• the upper limit of the above ratio is preferably 25% by weight or less, more preferably 20% by weight or less, further preferably 15% by weight or less, and 12% by weight or less. is particularly preferred, and 10% by weight or less is extremely preferred.
• the method for producing the (meth)acrylic resin of the second aspect is not particularly limited as long as it is a method capable of exhibiting the effects of the invention. From the viewpoints of flexibility in structural design, simplicity of polymerization, productivity, etc., it is preferable to produce by an emulsion polymerization method or a suspension polymerization method.
• a transparent resin base material When producing a transparent resin base material by the solution casting method, from the viewpoint of obtaining a film with excellent appearance and high transparency, it is difficult to cause foam marks on the surface and inside of the film during drying, and the use of ionic emulsifiers is recommended.
• It is preferably produced by an emulsion polymerization method in which polymerization is carried out in the presence of.
• maleimide monomers remaining in the polymerization process tend to hydrolyze and discolor the (meth)acrylic polymers.
• Polymerization using an emulsion polymerization method is preferable because these residual maleimide-based monomers can be effectively reduced.
• the polymerization initiator for polymerizing the (meth)acrylic polymer known ones can be used.
• persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate;
• Peroxide t-butylperoxyisopropyl carbonate, cumene hydroperoxide, p-menthane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di(8,5,5-trimethylhexanoyl)
• Organic peroxides such as peroxide, dilauroyl peroxide, and benzoyl peroxide: and the like can be used.
• the transparent resin substrate of the present disclosure may further contain polymer particles (I).
• Polymer particles (I) are crosslinked (meth)acrylic polymer particles having a weight average molecular weight of less than 200,000.
• the form of the polymer particles (I) is not limited, but for example, a graft copolymer having a core-shell structure is exemplified.
• a graft copolymer having a core-shell structure can impart mechanical strength such as bending resistance and cracking resistance to a transparent resin substrate.
• a solution of a (meth)acrylic resin dissolved in a solvent and a solution of a graft copolymer having a core-shell structure dissolved in a solvent are mixed. may be used to prepare the dope.
• a graft copolymer having a core-shell structure is called a multistage polymer, a multilayer structure polymer, or a core-shell type polymer.
• These polymers are polymers having a polymer layer (shell layer) obtained by polymerizing a monomer mixture in the presence of crosslinked polymer particles (core layer).
• core layer crosslinked polymer particles
• Each of the core layer and the shell layer may be composed of one layer, or may be composed of two or more layers.
• Such a graft copolymer is not particularly limited, and known ones can be used as appropriate.
• a monomer mixture containing an acrylic acid ester as a main component and a cross-linking agent are polymerized to form an acrylic acid ester-based rubbery polymer, and in the presence of the acrylic acid ester-based rubbery polymer, methacrylic acid
• examples thereof include graft copolymers obtained by polymerizing a monomer mixture containing an acid ester as a main component.
• the graft copolymer can be produced by ordinary emulsion polymerization using a known emulsifier. From the viewpoint of suppressing foam marks that may occur in the drying process when manufacturing a transparent resin base material by the solution casting method, it is manufactured by emulsion polymerization using an ionic emulsifier that is soluble in alcohol solvents. preferably. Further, for example, when the graft copolymer is granulated using a coagulant such as calcium chloride or magnesium chloride, the ionic emulsifier exists as a polyvalent cation salt. Therefore, it is preferable to wash the graft copolymer using a known washing method to reduce the content of salt in the graft copolymer, from the viewpoint of suppressing foam traces on the transparent resin substrate.
• the crosslinked (meth)acrylic polymer particles are, for example, a graft copolymer obtained by polymerizing a monomer mixture containing a methacrylic acid ester as a main component in the presence of an acrylic acid ester rubbery polymer. structure, the addition thereof tends to improve the mechanical strength of the transparent resin base material, while lowering the physical properties such as the elastic modulus and hardness of the base material.
• the content of the polymer particles (I) should be 50% by weight or less with respect to 100% by weight of the transparent resin substrate. is preferably less than 50% by weight, more preferably 30% by weight or less, particularly preferably 20% by weight or less, and extremely preferably 10% by weight or less, Most preferably, it is 5% by weight or less.
• the content of the polymer particles (I) is preferably 1% by weight or more, may be 2% by weight or more, or may be 3% by weight or more, relative to 100% by weight of the transparent resin substrate.
• the polymer particles (I) to be added have a hard polymer composition with a high glass transition temperature, or the cross-linking agent to be used Crosslinked polymer particles having a high degree of crosslinking may be obtained by adjusting the amount of .
• the transparent resin substrate containing the polymer particles (I) is produced by the solution casting method
• a solvent in which the polymer particles (I) are less likely to swell when preparing the dope For example, a graft copolymer having a high cross-linking density of the cross-linked polymer in the core layer suppresses penetration of solvent into the core layer and suppresses swelling of the graft copolymer, thereby reducing the density of molecular chains in the shell layer.
• it is considered that the steric repulsion effect of mutual particles is maintained, resulting in good particle dispersibility.
• the transparent resin substrate of the present disclosure is also used as a hard coat film having a hard coat layer on at least one main surface.
• a hard coat film having a hard coat layer on at least one main surface.
• cover window (front plate) applications such as foldable displays
• high surface hardness is required.
• a hard coat film is commonly used.
• the hard coat layer may be formed only on one main surface (single surface) of the transparent resin substrate, or may be formed on both main surfaces (both surfaces).
• Hard coat composition examples of the hard coat composition for forming the hard coat layer include (meth)acrylic acid ester-based, polyorganosiloxane-based, inorganic hybrid-based, urethane acrylate-based, polyester acrylate-based, and epoxy-based compositions. A plurality of these may be mixed, and particles such as organic/inorganic fillers may be added. Among them, a hard coat composition containing a polyorganosiloxane compound having an epoxy group is preferable from the viewpoint of obtaining a hard coat film having an excellent balance between flexibility (flexibility) and surface hardness.
• a hard coat film produced using a hard coat composition containing a polyorganosiloxane compound having an epoxy group exhibits high flexibility (flexibility) and flexibility, such as a cover window (front plate) of a foldable display. It can be suitably used for applications that require a balance with surface hardness.
• the polyorganosiloxane compound is, for example, a condensate of a silane compound represented by the following formula (1), the weight average molecular weight of the condensate is 500 to 20000, and the condensate contains the following formula (3)
• the molar ratio of the structural unit represented by the following formula (4) to the structural unit represented by ([structural unit represented by formula (3)]/[structural unit represented by formula (4)]) is less than 5.
• R 1 represents an alkylene group having 2 to 16 carbon atoms
• R 2 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms
• R 3 represents a hydrogen atom, and a an alkyl group, an aryl group having 6 to 25 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms
• x is 2 or 3
• Y is a glycidyloxy group represented by the following formula (2-1), or represents an alicyclic epoxy group represented by the following formula (2-2)).
• R 1 and Y have the same definitions as in formula (1) above.
• Z is a hydrogen atom, an alkoxy group having an alkyl moiety having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, a carbon represents an aryl group having 6 to 25 carbon atoms or an aralkyl group having 7 to 12 carbon atoms.
• R 1 represents an alkylene group having 2 to 16 carbon atoms, preferably a linear alkylene group.
• Linear alkylene groups include, for example, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, decamethylene group, dodecamethylene group, tetradecamethylene group, hexa A decamethylene group and the like can be mentioned.
• R 1 may further have a substituent having 1 to 6 carbon atoms. Examples of substituents having 1 to 6 carbon atoms include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, cyclohexyl group and phenyl group.
• R 2 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.
• alkyl groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, isopropyl, isobutyl, cyclohexyl, and ethylhexyl groups. mentioned.
• the alkyl group of R 2 is preferably a methyl group, an ethyl group, or a propyl group, more preferably a methyl group. .
• R 3 represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 25 carbon atoms, or an aralkyl group having 7 to 12 carbon atoms.
• R3 include a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an isopropyl group, an isobutyl group, a cyclohexyl group, and an ethylhexyl group. group, benzyl group, phenyl group, tolyl group, xylyl group, naphthyl group, phenethyl group and the like.
• x represents 2 or 3 and is appropriately selected according to the physical properties required for the hard coat.
• a polyorganosiloxane compound has an alkylene group with a specific chain length between an epoxy group and a silicon atom chemically connecting the epoxy group. Therefore, a hard coat film having a hard coat layer containing the polyorganosiloxane compound exhibits excellent flexibility.
• R 1 in the above formula (1) preferably represents an alkylene group having 6 to 14 carbon atoms, more preferably an alkylene group having 8 to 12 carbon atoms. preferable. When the number of carbon atoms in R 1 is 3 or less, the surface hardness of the cured product is improved, but the flexibility of the cured product may be difficult to exhibit.
• the weight average molecular weight of the polyorganosiloxane compound is preferably 500 or more from the viewpoint of increasing the hardness of the cured product. Also from the viewpoint of suppressing volatilization of the siloxane compound, the weight average molecular weight of the siloxane compound is preferably 500 or more. On the other hand, if the molecular weight is excessively high, cloudiness may occur due to reduced compatibility with other components. Therefore, the weight average molecular weight of the siloxane compound is preferably 20,000 or less.
• the weight average molecular weight of the polyorganosiloxane compound can be controlled by appropriately selecting the amount of water used for the reaction and the type and amount of catalyst. For example, the weight average molecular weight can be increased by increasing the amount of water initially charged.
• the polyorganosiloxane compound may contain structural units represented by the above formula (3) or (4) formed by hydrolysis and condensation reactions of the silane compound represented by the above formula (1).
• a structural unit represented by the above formula (3) hereinafter referred to as [SiO 3/2 body]
• a structural unit represented by the above formula (4) hereinafter referred to as [SiO 2/2 body]
• the ratio [SiO 3/2 ]/[SiO 2/2 ] is preferably less than 5, more preferably 4 or less, even more preferably 3 or less, and the lower limit is It can be 0.
• a hard coat layer made of a cured polyorganosiloxane compound is formed.
• a hard coat film having a high degree of flexibility will exhibit excellent flexibility.
• the resulting condensate has a dense structure and is flexible. is lowered, the flexibility of the hard coat film is lowered.
• the content and ratio of SiO 3/2 and SiO 2/2 in the polyorganosiloxane compound can be calculated, for example, by 29 Si-NMR measurement.
• the chemical shift of the silicon atom in the SiO 3/2 body and the chemical shift of the silicon atom in the SiO 2/2 body show signals at different positions in the spectrum, so the integration of each signal
• the ratio [SiO 3/2 body]/[SiO 2/2 body] can be obtained.
• the ratio of SiO 3/2 and SiO 2/2 in the polyorganosiloxane compound [SiO 3/2 ]/[SiO 2/2 ] depends on the amount of water used in the reaction, the type of catalyst and It can be controlled by properly choosing the amount. For example, the ratio [SiO 3/2 bodies]/[SiO 2/2 bodies] can be increased by increasing the amount of the catalyst initially charged.
• the amount of water required for the hydrolysis and condensation reaction is preferably 0.3 to 3 equivalents per equivalent of OR 2 groups directly bonded to silicon atoms (OR 2 groups in the above formula (1)). , more preferably 0.5 to 2 equivalents. If the amount of water is less than 0.3 equivalents, some of the OR 2 groups may remain unhydrolyzed. On the other hand, when the amount of water exceeds 3 equivalents, the reaction rate of hydrolysis and condensation reaction is too high to form a high-molecular-weight condensate, which may deteriorate the physical properties and transparency of the cured film.
• the number of OR 2 groups remaining in the polyorganosiloxane compound is preferably 2 or less, more preferably 1 or less, and 0.5 or less per molecule of the polyorganosiloxane compound. is more preferable, 0.1 or less is particularly preferable, and substantially none is extremely preferable.
• the residual ratio of epoxy structure-containing groups in the polyorganosiloxane compound obtained by the hydrolysis and condensation reaction of the silane compound represented by the above formula (1) is Higher is preferred.
• Percentage of residual epoxy structure-containing groups that is, the number of moles of epoxy structure-containing groups in the polyorganosiloxane compound obtained by condensation with respect to the number of moles of epoxy structure-containing groups possessed by the silane compound represented by the above formula (1), which is the raw material.
• the number ratio is preferably 20% or more, more preferably 40% or more, and even more preferably 60% or more.
• the residual ratio of epoxy structure-containing groups can be calculated by 1 H-NMR measurement.
• the hydrolysis and condensation reactions are carried out, for example, in the presence of a neutral salt catalyst.
• a neutral salt catalyst By carrying out the hydrolysis and condensation reactions in the presence of a neutral salt catalyst, the polyorganosiloxane compound can be obtained without deactivating the epoxy groups before, during and after the hydrolysis and condensation reactions and during storage.
• the neutral salt catalyst itself does not invade the production or storage containers, it can be used without restrictions on the materials of production or storage equipment.
• the catalyst itself electrophilically or nucleophilically reacts with various substances, or by changing the hydrogen ion concentration or hydroxide ion concentration in the reaction solution. , the ions contribute to the reaction, whereas neutral salts have extremely low reaction activity as described above.
• the diluting solvent used in the production of the polyorganosiloxane compound is preferably a water-soluble alcohol compound or ether compound. This is because most of the silane compounds represented by the above formula (1) have low compatibility with neutral salts and water used for hydrolysis. This is because it is preferable that
• silane compound (1) represented by the above formula (1) having an epoxy group in addition to the silane compound (1) represented by the above formula (1) having an epoxy group, a silane represented by the following formula (5) having no epoxy group Compounds may also be used.
• R 4 is selected from the group consisting of substituted or unsubstituted alkyl groups having 1 to 10 carbon atoms, alkenyl groups, aryl groups having 6 to 25 carbon atoms, and aralkyl groups having 7 to 12 carbon atoms.
• R 5 represents a hydrogen atom or a C 1-10 alkyl group
• R 6 represents a hydrogen atom, a C 1-10 alkyl group, a C 6 ⁇ 25 aryl group or C7-12 aralkyl group
• x represents 2 or 3.
• the number of epoxy groups contained in one molecule of the polyorganosiloxane compound is as large as possible.
• the molar ratio of the silane compound represented by the above formula (5) to the silane compound represented by the above formula (1) is preferably 2 or less, more preferably 1 or less. , is more preferably 0.4 or less, and particularly preferably 0.2 or less.
• the molar ratio of the silane compound represented by the above formula (5) to the silane compound represented by the above formula (1) may be zero.
• the content of the polyorganosiloxane compound in the hard coat composition is preferably 40 parts by weight or more with respect to the total solid content of 100 parts by weight. It is more preferably 60 parts by weight or more, more preferably 60 parts by weight or more.
• the hard coat composition preferably contains a photocationic polymerization initiator.
• a photocationic polymerization initiator is a compound (photoacid generator) that generates an acid upon irradiation with an active energy ray. The acid generated from the photoacid generator promotes the ring-opening reaction and polymerization reaction of the epoxy groups of the polyorganosiloxane compound, forms intermolecular crosslinks, and cures the hard coat composition.
• Photocationic polymerization initiators include, for example, strong acids such as toluenesulfonic acid and boron tetrafluoride; onium salts such as sulfonium salts, ammonium salts, phosphonium salts, iodonium salts, and selenium salts; iron-allene complexes; silanol-metal chelate complexes; sulfonic acid derivatives such as disulfones, disulfonyldiazomethanes, disulfonylmethanes, sulfonylbenzoylmethanes, imidosulfonates, and benzoinsulfonates; organic halogen compounds;
• the content of the photocationic polymerization initiator in the hard coat composition is preferably 0.05 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the polyorganosiloxane compound. more preferably 0.2 to 2 parts by weight.
• the hard coat composition may further contain a cationic curable compound other than the polyorganosiloxane compound as a reactive diluent.
• a compound having a cationic polymerizable functional group such as an epoxy group, a vinyl ether group, an oxetane group, or an alkoxysilyl group is used as the reactive diluent for cationic photopolymerization.
• the reactive diluent one having an epoxy group is preferable because the reactivity with the epoxy group of the polyorganosiloxane compound is high.
• the cationic curable compounds may be used singly or in combination of two or more.
• the content of the reactive diluent in the hard coat composition is preferably 100 parts by weight or less, more preferably 50 parts by weight or less, relative to 100 parts by weight of the polyorganosiloxane compound.
• the hard coat composition may contain a photosensitizer for the purpose of improving the photosensitivity of the photocationic polymerization initiator.
• the hard coat composition may contain a solvent. When a solvent is contained, it is preferably one that does not dissolve the transparent resin substrate.
• the content of the solvent in the hard coat composition is preferably 500 parts by weight or less, more preferably 300 parts by weight or less, and 100 parts by weight or less with respect to 100 parts by weight of the polyorganosiloxane compound. is more preferable.
• the hard coat composition may contain additives such as inorganic pigments, organic pigments, surface conditioners, surface modifiers, plasticizers, dispersants, wetting agents, thickeners and antifoaming agents.
• the hard coat composition may also contain a thermoplastic or thermosetting resin material other than the above polyorganosiloxane compound.
• the siloxane compound and/or the resin material other than the siloxane compound has radical polymerizability, the hard coat composition may contain a radical polymerization initiator in addition to the photocationic polymerization initiator.
• the hard coat film of the present disclosure is obtained by coating a hard coat composition on a transparent resin substrate, removing the solvent by drying if necessary, and then irradiating an active energy ray to cure the hard coat composition. be done.
• the surface of the transparent resin substrate may be subjected to surface treatment such as corona treatment or plasma treatment. Moreover, you may provide the easy-adhesion layer (primer layer) etc. which are mentioned later on the surface of a transparent resin base material.
• the hard coat composition By irradiating the hard coat composition with active energy rays, an acid is generated from the photocationic polymerization initiator, and the epoxy groups of the polyorganosiloxane compound are ring-opened and cationic polymerized to proceed with curing.
• the hard coat composition contains a reactive diluent, a polymerization reaction between the epoxy group of the siloxane compound and the reactive diluent also occurs in addition to the polymerization reaction between the siloxane compounds.
• active energy rays to be irradiated during photocuring include visible light, ultraviolet rays, infrared rays, X-rays, ⁇ rays, ⁇ rays, ⁇ rays, electron beams, and the like.
• Ultraviolet rays are preferable as the active energy rays because of their high curing reaction speed and excellent energy efficiency.
• the cumulative irradiation dose of active energy rays is, for example, about 50 to 10,000 mJ/cm 2 , and may be set according to the type and amount of the cationic photopolymerization initiator, the thickness of the hard coat layer, and the like.
• the curing temperature is not particularly limited and is usually 100° C. or less.
• the thickness of the transparent resin substrate is not particularly limited, and can be appropriately selected, for example, from the range of 1 to 1000 ⁇ m, preferably 5 to 500 ⁇ m, more preferably 10 to 200 ⁇ m, still more preferably 15 to 150 ⁇ m.
• the thickness of the hard coat layer is preferably 10 ⁇ m or more, more preferably 20 ⁇ m or more, even more preferably 30 ⁇ m or more, and particularly preferably 40 ⁇ m or more. Also, the thickness of the hard coat layer is preferably 100 ⁇ m or less, more preferably 80 ⁇ m or less. If the thickness of the hard coat layer is less than 10 ⁇ m, mechanical properties such as surface hardness and dent resistance may not be sufficiently improved. On the other hand, when the thickness of the hard coat layer is more than 100 ⁇ m, the transparency and flexibility may be lowered.
• the total thickness of the hard coat film of the present disclosure can be appropriately selected from the range of 40-500 ⁇ m, preferably 80-250 ⁇ m, more preferably 100-200 ⁇ m.
• the ratio between the thickness of the hard coat layer and the thickness of the transparent resin substrate is not particularly limited, and is, for example, 1/10 to 10/1. can be selected as appropriate.
• the hard coat layer in the hard coat film of the present disclosure preferably has a polymer matrix crosslinked by ring-opening and polymerization reaction of epoxy groups possessed by the polyorganosiloxane compound. In this case, a surface hardness comparable to that of glass is achieved. obtain.
• the pencil hardness of the hard coat layer-forming surface of the hard coat film of the present disclosure is preferably HB or higher, more preferably H or higher, even more preferably 2H or higher, and particularly 4H or higher. preferable.
• the total light transmittance of the hard coat film of the present disclosure is preferably 80% or higher, more preferably 85% or higher, and even more preferably 88% or higher. Further, the haze of the hard coat film of the present disclosure is preferably 1.5% or less, more preferably 0.9% or less, even more preferably 0.6% or less, and 0.5% or less. % or less is particularly preferable.
• the hard coat film of the present disclosure may have an easy-adhesion layer between the transparent resin substrate and the hard coat layer.
• the easy-adhesive composition forming the easy-adhesion layer is not particularly limited, and for example, one containing a water-based urethane resin and a cross-linking agent is known. Examples of cross-linking agents include oxazoline-based and epoxy-based agents.
• the polyurethane resin having a carboxyl group and a tri- or higher polyfunctional epoxy-based cross-linking agent.
• An easy-adhesion layer made of an adhesive composition can be suitably used.
• the polyfunctional epoxy-based cross-linking agent preferably has 4 or more epoxy functional groups.
• the transparent resin base material of the present disclosure has high flexibility (flexibility) and excellent optical properties, and therefore can be used as a base material for various flexible displays.
• Examples include a curved display with a curved shape; a foldable or bendable display that is a foldable display; a rollable or slidable display that is a rollable display;
• a display device for realizing a flexible display is not particularly limited, but an organic EL display having a flexible light-emitting layer can be mentioned.
• Examples of transparent resin substrates used in flexible organic EL displays include films for cover windows. Since the transparent resin substrate of the present disclosure has high flexibility (flexibility) and excellent optical properties, the hard coat film formed by forming the hard coat layer on the transparent resin substrate also has high flexibility (flexibility). ).
• the transparent resin base material of the present disclosure is suitably used as a film for impact absorption, a back film, a protective film laminated on the surface of another base material, and the like.
• the laminated protective film can be used, for example, to protect substrates such as thin glass, TAC (triacetyl cellulose), and COP (cycloolefin polymer) from scratches on the surface thereof, and to prevent the thin glass from shattering.
• the present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples.
• the number of parts for each substance is based on weight.
• volume average particle size of polymerized latex Using Microtrac UPA150 (manufactured by Nikkiso Co., Ltd.), the volume average particle size of polymerized latex of (meth)acrylic resin was determined based on the principle of dynamic light scattering method.
• volume average particle diameter of the (meth)acrylic resin bead-like particles was determined based on the principle of the laser diffraction scattering method.
• Glass transition temperature (Tg) The glass transition temperature (Tg) of the transparent resin substrate was measured using a differential scanning calorimeter (DSC, model: Q1000, manufactured by TA Instruments). The sample was placed under a nitrogen stream and heated to 200°C at a heating rate of 10°C/min, then rapidly cooled to 40°C and heated again to 200°C at a heating rate of 10°C/min. The average of the extrapolated glass transition start temperature and the extrapolated glass transition end temperature was determined for the glass transition observed during the second temperature rise, and this value was defined as the glass transition temperature (Tg).
• DSC differential scanning calorimeter
• the haze of the obtained transparent resin substrate was measured by the method described in JIS K7105 using a haze meter (HZ-V3, manufactured by Suga Test Instruments Co., Ltd.).
• the transparent resin substrate is preheated for 5 minutes at a temperature condition of +10°C with respect to the glass transition temperature of the substrate before stretching, using a stretching machine with a drying oven, and then fixed at a speed of 100 mm/minute. It was uniaxially stretched 0.5 times.
• the thickness of the transparent resin base material was measured using a Digimatic indicator (manufactured by Mitutoyo Co., Ltd.).
• a test piece was cut out from the central portion of the transparent resin substrate having a thickness of 40 ⁇ m after uniaxial stretching.
• the in-plane retardation Re of this test piece was measured using an automatic birefringence meter (KOBRA-WR manufactured by Oji Keisoku Co., Ltd.) under the conditions of a wavelength of 590 nm and an incident angle of 0°. At the same time, measurement was also performed at an incident angle of 40°, and the thickness direction retardation Rth was also measured. The measurement was performed three times while moving the test piece to change the measurement point, and the average value was obtained.
• KOBRA-WR automatic birefringence meter
• the retardation of a 38 ⁇ m thick transparent PET film was also measured and converted to a numerical value equivalent to a thickness of 40 ⁇ m.
• orientation birefringence The orientation birefringence of the transparent resin substrate was obtained by dividing the in-plane retardation Re measured by the above method by the thickness of the transparent resin substrate.
• a strip-shaped test piece of 15 mm x 85 mm was cut out from an unstretched transparent resin base material before being uniaxially stretched (cut out so that the long side is in the TD direction).
• the in-plane retardation Re was measured under the conditions of a wavelength of 590 nm and an incident angle of 0° using an automatic birefringence meter (manufactured by Oji Keisoku Co., Ltd., KOBRA-WR). At that time, one of the long sides of the test piece was fixed, and the in-plane retardation Re was measured while changing the load (stress) by 0.5 kgf in the range from no load to 4 kgf on the other side.
• a constant of proportionality was obtained from the relational expression between the stress and the in-plane retardation Re and was taken as the photoelastic constant.
• the sign of the photoelastic constant was determined to be positive or negative from the change in orientation angle with respect to stress.
• the photoelastic constant of a 38 ⁇ m-thick transparent PET film manufactured by Toyobo Co., Ltd., Cosmoshine A4300 was also measured.
• test piece of 15 mm ⁇ 85 mm was cut out from a transparent resin substrate having a thickness of 40 ⁇ m, and both ends were joined with a tape to prepare a cylindrical test piece.
• a curved cylindrical specimen was placed perpendicular to the imaging direction and the joint was fixed downward.
• a two-dimensional birefringence evaluation device (WPA-200-L, manufactured by Photonic Lattice Co., Ltd.) was used to visualize the phase difference of the entire test piece under the condition of a wavelength of 543 nm while the test piece was stressed.
• the phase difference was read, and the difference ( ⁇ phase difference) was obtained.
• the ⁇ phase difference of a 38 ⁇ m-thick transparent PET film manufactured by Toyobo Co., Ltd., Cosmoshine A4300 was also measured, and converted to a numerical value per 40 ⁇ m thickness.
• the weight average molecular weight of the transparent resin base material was calculated by a standard polystyrene conversion method using gel permeation chromatography (GPC).
• GPC gel permeation chromatography
• the GPC column was filled with polystyrene crosslinked gel (model: TSK gel Super HZM-H, manufactured by Tosoh Corporation), and tetrahydrofuran (THF) was used as the GPC solvent.
• TSK gel Super HZM-H tetrahydrofuran
• the imidization rate was calculated using IR as follows. (Meth)acrylic resin pellets were dissolved in methylene chloride, and the IR spectrum of the solution was measured at room temperature using TravelIR manufactured by SensIR Technologies. From the obtained IR spectrum, the imidization rate ( Im% ( IR)) was obtained.
• the term "imidization ratio" refers to the proportion of imidocarbonyl groups in all carbonyl groups.
• the polymerization conversion rate was 99.5% and the average particle size was 600 ⁇ .
• a monomer mixture consisting of 84 parts of MMA, 1 part of n-BMA, 7 parts of PhMI, and 0.02 parts of 2-EHTG was continuously added to the reactor over 70 minutes to initiate the reaction. gone.
• 15 minutes after the addition of the monomer mixture 0.7 part of DSS was added dropwise following the addition of the monomer mixture and continuously added to the reactor.
• the stirring speed was increased to 200 rpm 55 minutes after the start of addition of the monomer mixture, and to 240 rpm after 70 minutes.
• a mixed aqueous solution of ED: 0.0055 parts and FeSO 4 : 0.0015 parts, SFS: 0.06 parts, DSS: 0.2 parts, and t-BHP: 0.06 were added to the reactor in order. Thereafter, the reaction was continued for 60 minutes to complete the polymerization and obtain a polymerized latex. The polymerization conversion rate was 99.9% and the average particle size was 1250 ⁇ . Then, the resulting polymerized latex was evaporated to dryness in a drying oven at 50° C. for 24 hours to obtain a white powdery (meth)acrylic polymer C.
• the (meth)acrylic resin D is a glutarimide acrylic resin produced using polymethyl methacrylate as a raw material resin and monomethylamine as an imidizing agent.
• a tandem type reaction extruder with two extrusion reactors arranged in series was used.
• the first extruder and the second extruder are intermeshing co-rotating twin screws with a diameter of 75 mm and an L/D (ratio of extruder length L to diameter D) of 74.
• An extruder was used, and a constant weight feeder (manufactured by Kubota Corporation) was used to supply raw material resin to the raw material supply port of the first extruder.
• the pressure reduction degree of each vent in the first extruder and the second extruder was -0.095 MPa. Furthermore, a pipe with a diameter of 38 mm and a length of 2 m connects the first extruder and the second extruder, and the part internal pressure control that connects the resin discharge port of the first extruder and the raw material supply port of the second extruder A constant flow pressure valve was used for the mechanism.
• the resin (strand) discharged from the second extruder was cooled by a cooling conveyor and then cut into pellets by a pelletizer.
• the discharge port of the first extruder, the first extruder, and A resin pressure gauge was provided at the central portion of the connecting part with the second extruder and at the discharge port of the second extruder.
• imide resin intermediate 1 was produced using polymethyl methacrylate (weight average molecular weight: 105,000) as the raw material resin and monomethylamine as the imidizing agent.
• the temperature of the highest temperature part of the extruder was 280° C.
• the screw rotation speed was 55 rpm
• the raw material resin supply amount was 150 kg/hour
• the amount of monomethylamine added was 2.0 parts per 100 parts of the raw material resin.
• a constant flow pressure valve was installed immediately before the raw material supply port of the second extruder, and the pressure of the monomethylamine injection section of the first extruder was adjusted to 8 MPa.
• (meth)acrylic resin D the imidization rate, glutarimide unit content, acid value, and glass transition temperature were measured according to the methods described above. As a result, the imidization rate was 13%, the glutarimide unit content was 7% by weight, the acid value was 0.4 mmol/g, and the glass transition temperature was 123°C.
• MMA 25 parts, BA: 1.5 parts, St: 0.5 parts, ALMA: 0.15 parts, n-OM: 0.3 parts, and polyoxyethylene lauryl ether phosphate: 0.1 parts was continuously added to the reactor over 80 minutes to carry out the reaction. After that, the reaction was continued for 60 minutes, and sodium hydroxide: 0.03 part and KPS: 0.08 part were charged. Then, a monomer mixture consisting of 40 parts of BA, 10 parts of St, 0.75 parts of ALMA, and 0.2 parts of polyoxyethylene lauryl ether phosphate was continuously added to the reactor over 150 minutes. , Immediately after the addition of the monomer mixture, 0.02 part of KPS was charged and the reaction was continued for 120 minutes.
• polymer particles (I) having an average particle size of 2400 ⁇ .
• the polymerization conversion rate was 99.5%.
• the weight average molecular weight of polymer particles (I) was 60,000.
• the coating film was dried together with the PET film in a dry atmosphere at 40° C. for 1 hour, it was peeled off from the PET film.
• the resulting half-dried film of (meth)acrylic resin A was fixed to a stainless steel frame and dried in a dry atmosphere at 140° C. for 60 minutes to remove the residual solvent. got After that, the dried film of acrylic resin A was preheated for 5 minutes using a stretching machine with a drying oven at a temperature of +10°C with respect to the glass transition temperature of acrylic resin A, and then stretched at a speed of 100 mm/min. to obtain a transparent resin substrate A having a thickness of 40 ⁇ m.
• the weight average molecular weight of the transparent resin substrate A was 1,980,000.
• Production Example 3 Production of transparent resin substrate C
• the same method as in Production Example 1 was carried out, and a thickness of 40 ⁇ m was obtained.
• a transparent resin substrate C was obtained.
• the weight average molecular weight of the transparent resin substrate C was 690,000.
• pellets were fed at a rate of 10 kg/hour and melt extruded to obtain a film having a thickness of 60 ⁇ m.
• the glass transition temperature of the film was 122°C.
• the width is fixed 1.5 times uniaxially stretched at a speed of 100 mm / min. was performed to obtain a transparent resin substrate E having a thickness of 40 ⁇ m.
• the weight average molecular weight of the transparent resin substrate E was 100,000.
• pellets were fed at a rate of 10 kg/hour and melt extruded to obtain a film having a thickness of 60 ⁇ m.
• the glass transition temperature of the film was 121°C.
• the width is fixed 1.5 times at a speed of 100 mm / min. was performed to obtain a transparent resin substrate F having a thickness of 40 ⁇ m.
• the weight average molecular weight of the transparent resin substrate F was 95,000.
• Aqueous polyurethane having a carboxyl group (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., trade name: Superflex 210, solid content: 35% by weight): For 100 parts, a tetrafunctional epoxy-based cross-linking agent (manufactured by Nagase ChemteX Corporation , trade name: Denacol EX-512, solid content: 100% by weight, epoxy equivalent: 168 g/eq): 2.02 parts, pure water: 250 parts, and mixed with a magnetic stirrer to obtain a solid content concentration of 10.5. % by weight of the easy-adhesive composition was obtained.
• Example 1 Production of hard coat film 1
• the hard coat composition was applied to the main surface 1 of the transparent resin substrate A having a thickness of 40 ⁇ m using a bar coater so that the dry film thickness was 40 ⁇ m, and heated at 120° C. for 10 minutes. After that, using a high-pressure mercury lamp, ultraviolet rays were irradiated so that the integrated light amount of UVA (wavelength range: 320 to 400 nm) was 880 mJ/cm 2 and the irradiation intensity was 220 mW/cm 2 . The composition was allowed to cure.
• UVA wavelength range: 320 to 400 nm
• the hard coat composition was applied onto the main surface 2 of the transparent resin substrate A using a bar coater in the same manner as for the main surface 1 so that the dry film thickness would be 40 ⁇ m.
• the hard coat composition on main surface 2 was cured by irradiating ultraviolet rays.
• the obtained film was heated at 60° C. for 24 hours to obtain hard coat film 1 having hard coat layers on both main surface 1 and main surface 2 .
• Example 2 Production of hard coat film 2
• the easy-adhesive composition was applied using a bar coater so that the dry film thickness was 1 ⁇ m, and heated at 100° C. for 10 minutes. Thereafter, the hard coat composition was applied and cured in the same manner as in Example 1 on the surface to which the easy-adhesive composition was applied. After 24 hours, the easy-adhesive composition and the hard coat composition were applied in order on the main surface 2 of the transparent resin substrate B in the same manner as for the main surface 1, and cured. After 24 hours, the obtained film was heated at 60° C. for 24 hours to obtain a hard coat film 2 having hard coat layers on both main surface 1 and main surface 2 .
• Example 3 Production of hard coat film 3
• a hard coat film 3 having hard coat layers on both main surface 1 and main surface 2 was obtained in the same manner as in Example 1, except that a transparent resin substrate C having a thickness of 40 ⁇ m was used.
• main surface 2 of transparent resin substrate D was subjected to corona discharge treatment with the same irradiation intensity as main surface 1 .
• a hard coat composition was applied and cured in the same manner as for main surface 1 .
• the obtained film was heated at 60° C. for 24 hours to obtain a hard coat film 4 having hard coat layers on both main surface 1 and main surface 2 .
• Comparative Example 2 Production of hard coat film 5
• Hard coat layers were provided on both main surfaces 1 and 2 in the same manner as in Comparative Example 1, except that a transparent resin substrate E with a thickness of 40 ⁇ m was used. A hard coat film 5 was obtained.
• the transparent resin substrates of Examples 1 to 3 had low haze (internal haze), low orientation birefringence, photoelastic constant, in-plane retardation Re, and thickness direction retardation Rth, and had excellent optical properties. It turns out that it is a resin base material. Further, it can be seen that the hard coat films 1 to 3 having a hard coat layer on the transparent resin base material of Examples 1 to 3 exhibit an excellent bending number. Furthermore, it can be seen that the hard coat film 1 has an excellent balance between the number of times of bending and the surface hardness.
• the transparent resin substrates of Comparative Examples 1 to 3 exhibited optical properties corresponding to those of the transparent resin substrates of Examples 1 to 3, but the transparent resin substrates of Comparative Examples 1 to 3 were provided with a hard coat layer.
• the hard coat films 4 to 6 had a low bending number.
• the transparent resin substrates of Examples 1 to 3 had low orientation birefringence, photoelastic constant, in-plane retardation Re, and thickness direction retardation Rth, and the ⁇ phase difference in the two-dimensional birefringence evaluation was also very small. . Further, in the phase contrast imaging image in the two-dimensional birefringence evaluation, the height of the phase difference was continuous. That is, if the transparent resin substrate has excellent optical properties as in Examples 1 to 3, the phase difference (optical distortion) caused by the deformation of the substrate is small, and the change is continuous. Therefore, even when an external force such as bending or winding acts on a flexible display or the like, it is presumed that the change in image quality (picture quality) is extremely small.
• the transparent PET film of Comparative Example 4 has very large orientation birefringence, photoelastic constant, in-plane retardation Re, and thickness direction retardation Rth. was big. Furthermore, in the phase contrast imaging image in the two-dimensional birefringence evaluation, the height of the phase difference was repeated in a striped pattern, and a mottled pattern was observed. When such a base material is used, when an external force such as bending or winding is applied to a flexible display, etc., the change in phase difference becomes very large around the area where the stress is applied, resulting in light leakage and image quality (image quality). It is speculated that the change in

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