Adhesive film, optical member, and optical display apparatus

Abstract

To provide an adhesive film that has high peel strength measured with respect to a non-metal base material under high temperature conditions and under high temperature and high humidity conditions, and high peel strength measured with respect to a metal base material under high temperature conditions and under high temperature and high humidity conditions, and provides a stacked structure of a non-metal base material, an adhesive film and a metal base material with excellent holdability under high temperature and high humidity conditions.SOLUTION: An adhesive film for a non-metal base material and a metal base material contains a cured product of a composition including (meth)acrylic binder and a curing agent, and has a peel strength, measured at 60°C and 93% relative humidity, of 400 gf / inch or more with respect to each of the non-metal base material and the metal base material. The (meth)acrylic binder is formed from a monomer mixture containing 1 wt.% to 10 wt.% of a cycloaliphatic group-containing (meth)acrylic monomer.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an adhesive film, an optical member including the same, and an optical display device including the same.

Background Art

[0002] Generally, an adhesive film is used for bonding optical elements in an optical display device. In recent years, with the increasing interest in portable optical display devices, the adhesive film included in the optical display device is required to have excellent portable physical properties.

[0003] An optical element can include layers made of the same or different materials. For example, the optical element may include a layer containing a polymer or a layer containing a metal. Therefore, the adhesive film can also bond the layer containing the polymer and the layer containing the metal. The adhesive film can provide excellent holding properties only when the peeling force with respect to each of the layer containing the polymer and the layer containing the metal is excellent. In addition, durability is essentially required for an optical display device. Therefore, it is preferable that the adhesive film provides excellent peeling force with respect to each of the layer containing the polymer and the layer containing the metal under high temperature and high temperature and high humidity conditions, respectively.

[0004] The background art of the present invention is disclosed in Japanese Patent Application Laid-Open No. 2020-111734 and the like.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] It provides an adhesive film that has a high peel strength measured against non-metallic substrates at high temperatures and high temperature and high humidity, also has a high peel strength measured against metallic substrates at high temperatures and high temperature and high humidity, and provides excellent holding properties at high temperature and high humidity in a laminated structure of a non-metallic substrate, an adhesive film, and a metallic substrate.

[0007] It provides an optical member having a laminated structure of a non-metallic substrate, an adhesive film, and a metallic substrate, which is excellent in reliability and holding properties at high temperatures and high temperature and high humidity.

Means for Solving the Problems

[0008] According to one embodiment, as the adhesive film, the adhesive film is an adhesive film for a non-metallic substrate and a metallic substrate, the adhesive film has a peel strength of 400 gf / inch or more when measured against the non-metallic substrate and the metallic substrate at 60 °C and a relative humidity of 93%, respectively, the adhesive film includes a cured product of a composition containing a (meth)acrylic binder and a thermosetting agent, and the (meth)acrylic binder is a (meth)acrylic binder of a monomer mixture containing 1% by weight to 10% by weight of an alicyclic group-containing (meth)acrylic monomer.

[0009] According to one embodiment, as the optical member, the optical member has a non-metallic substrate, an adhesive film, and a metallic substrate laminated in this order, the adhesive film includes a cured product of a composition containing a (meth)acrylic binder and a thermosetting agent, and the (meth)acrylic binder is a (meth)acrylic binder of a monomer mixture containing 1% by weight to 10% by weight of an alicyclic group-containing (meth)acrylic monomer.

[0010] According to one embodiment, as the optical display device, the optical display device includes the adhesive film or the optical member.

Advantages of the Invention

[0011] It is possible to provide an adhesive film that has a high peel strength measured against a non-metallic substrate at high temperature and high temperature / high humidity, also has a high peel strength measured against a metallic substrate at high temperature and high temperature / high humidity, and provides excellent holding properties at high temperature / high humidity in a laminated structure of a non-metallic substrate, an adhesive film, and a metallic substrate.

[0012] It is possible to provide an optical member having a laminated structure of a non-metallic substrate, an adhesive film, and a metallic substrate, which is excellent in reliability and holding properties at high temperature and high temperature / high humidity.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

[0014] In FIGS. 1 and 2, the X-axis represents the content (unit: wt%) of the alicyclic group-containing (meth)acrylic monomer in the monomer mixture, and the Y-axis represents the peel strength (unit: gf / inch).

[0015] In FIGS. 1 and 2, ●: peel strength measured at 60°C, ■: peel strength measured at 60°C and 93% relative humidity.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described in more detail. However, the technology disclosed in this application is not limited to the embodiments described herein and may be embodied in other forms. However, the embodiments introduced herein are provided to make the disclosed content thorough and complete and to fully convey the idea of the present invention to those skilled in the art.

[0017] The terms used herein are for the purpose of describing exemplary embodiments only and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0018] As used herein, the "glass transition temperature of the homopolymer" can mean the glass transition temperature (Tg) measured using a TA Instrument DSC Discovery for the homopolymer of the monomer to be measured. Specifically, for the homopolymer of the monomer to be measured, the temperature is raised to 180°C at a heating rate of 20°C / min, gradually cooled to -100°C, and then heated to 100°C at a heating rate of 10°C / min to obtain data of the endothermic transition curve, and the inflection point of the endothermic transition curve can be determined as the glass transition temperature.

[0019] As used herein, the glass transition temperature of the "(meth)acrylic binder" can be measured by a method known to those skilled in the art using a differential scanning calorimeter (DSC).

[0020] As used herein, "(meth)acrylic" means acrylic and / or methacrylic.

[0021] As used herein, the "weight average molecular weight" may be a value determined by polystyrene conversion in gel permeation chromatography.

[0022] In this specification, the "shear deformation rate" is a value measured at 60°C and means the degree of deformation when a force in a certain shear direction is applied. Referring to Figure 4, when measuring the strain applied to the adhesive film under the conditions in the following experimental example over time with a constant force, the strain value at 600 seconds corresponds to the shear deformation rate.

[0023] In this specification, when describing a numerical range, "X~Y" means X or more and Y or less (X ≤ and ≤ Y).

[0024] According to one embodiment, it is possible to provide an adhesive film that has a high peel strength measured against a non-metallic substrate at high temperature and high temperature and high humidity, has a high peel strength measured against a metallic substrate at high temperature and high temperature and high humidity, and provides excellent holding properties in a laminated structure of a non-metallic substrate, an adhesive film, and a metallic substrate.

[0025] In this specification, the "non-metallic substrate" may be a non-metallic substrate that forms an optical element in an optical display device or is included in an optical element. Specifically, the non-metallic substrate may be a polymer film such as a polyester film such as polyethylene terephthalate (PET), a cyclic olefin polymer film, a polycarbonate film, a (meth)acrylic film, a cellulose ester film, etc. Preferably, the non-metallic substrate may be a polyester polymer film such as polyethylene terephthalate (PET).

[0026] In this specification, the "metallic substrate" may form an optical element in an optical display device or may be a metallic substrate included in an optical element. Specifically, the metallic substrate may be a layer formed of a normal metal such as an alkali metal or an alkaline earth metal. When measuring the peel strength, the metallic substrate can be substituted with a SUS (steel use stainless) metal plate.

[0027] In this specification, the "peeling force at high temperature" may be the peeling force measured at 60°C. In this specification, the "peeling force at high temperature and high humidity" can be the peeling force measured at 60°C and 93% relative humidity. Although not particularly limited, since the peeling force at high temperature is measured in a constant temperature chamber at 60°C, the relative humidity may be extremely low.

[0028] The adhesive film is an adhesive film for the non-metallic base material and the metallic base material, and the adhesive film may adhere to either the non-metallic base material or the metallic base material.

[0029] The adhesive film has a peeling force measured at high temperature and high temperature and high humidity of 400 gf / inch or more with respect to the non-metallic base material. Within this range, excellent holding properties in repeated holding can be provided. For example, the peeling force may be 400 gf / inch to 1000 gf / inch, or 500 gf / inch to 800 gf / inch.

[0030] The adhesive film has a peeling force measured at high temperature and high temperature and high humidity of 400 gf / inch or more with respect to the metallic base material. Generally, an adhesive film exhibits a lower peeling force on a metallic base material compared to a non-metallic base material. The adhesive film is characterized in that it provides a high peeling force not only for the non-metallic base material but also for the metallic base material at high temperature and high temperature and high humidity. Within the above range of peeling force, excellent holding properties in repeated holding can be provided. For example, the peeling force may be 400 gf / inch to 1000 gf / inch, or 500 gf / inch to 800 gf / inch.

[0031] According to one embodiment, the adhesive film may have a value of the following mathematical formula (1) of 1 or more, for example, 1 to 1.5, or more than 1 and 1.5 or less. Within this range, the effect of stabilizing the adhesion to the non-metallic base material at high temperature and high humidity and the effect of increasing the adhesive strength between the non-metallic base material and the adhesive film can be achieved.

[0032] A2 / A1 (1) (In the formula (1), A1 is the peel strength (unit: gf / inch) at 60°C of the pressure-sensitive adhesive film with respect to the non-metallic base material of the pressure-sensitive adhesive film, and A2 is the peel strength (unit: gf / inch) at 60°C and 93% relative humidity of the pressure-sensitive adhesive film with respect to the non-metallic base material of the pressure-sensitive adhesive film.)

[0033] According to one embodiment, the pressure-sensitive adhesive film may have a value of the following formula (2) of 1 or more, for example, 1 to 1.5, more than 1 and 1.5 or less. Within the above range, the effect of increasing the adhesion between the metallic base material and the pressure-sensitive adhesive film can be achieved.)

[0034] B1 / B2 (2) (In the formula (2), B1 is the peel strength (unit: gf / inch) at 60°C of the pressure-sensitive adhesive film with respect to the metallic base material of the pressure-sensitive adhesive film, and B2 is the peel strength (unit: gf / inch) at 60°C and 93% relative humidity of the pressure-sensitive adhesive film with respect to the metallic base material of the pressure-sensitive adhesive film.)

[0035] According to one embodiment, the pressure-sensitive adhesive film may have a shear deformation rate measured at 60°C of 15% or more, for example, 25% or more. Specifically, the pressure-sensitive adhesive film may have a shear deformation rate measured at 60°C of 15% to 50%, 25% to 50%. Within the above range, excellent holding properties can be easily provided in the laminated structure of the non-metallic base material, the pressure-sensitive adhesive film, and the metallic base material.)

[0036] According to one embodiment, the pressure-sensitive adhesive film may have a storage modulus at -20°C of 2 MPa or less, for example, 0.1 MPa to 1 MPa, 0.1 MPa to 0.5 MPa, and a storage modulus at 60°C of 0.5 MPa or less, for example, 0.01 MPa to 0.5 MPa, 0.01 MPa to 0.1 MPa. Within the above range, excellent holding properties can be provided, and the adhesion to the metallic base material and the non-metallic base material can be easily enhanced.)

[0037] The pressure-sensitive adhesive film may be a pressure-sensitive adhesive (PSA) film as a (meth)acrylic pressure-sensitive adhesive film in a specific example.

[0038] According to one embodiment, the pressure-sensitive adhesive film includes a cured product of a composition containing a (meth)acrylic binder and a thermosetting agent. The (meth)acrylic binder is a (meth)acrylic copolymer of a monomer mixture containing 1% to 10% by weight of an alicyclic group-containing (meth)acrylic monomer. The composition is a thermosetting composition. The pressure-sensitive adhesive film includes a thermoset of the composition, and by including 1% to 10% by weight of the alicyclic group-containing (meth)acrylic monomer in the monomer mixture, the peel strength at high temperature and high temperature and high humidity can be increased for both non-metallic substrates and metallic substrates, and excellent holding properties at high temperature and high humidity can be provided.

[0039] When the content of the alicyclic group-containing (meth)acrylic monomer in the monomer mixture is less than 1% by weight, the peel strength at high temperature and high humidity for non-metallic substrates and metallic substrates decreases, so the holding properties at high temperature and high humidity may deteriorate. When the content of the alicyclic group-containing (meth)acrylic monomer in the monomer mixture exceeds 10% by weight, the peel strength at high temperature and high humidity for non-metallic substrates and metallic substrates decreases, and the shear deformation rate at 60°C decreases, resulting in a problem that the holding properties at high temperature and high humidity may deteriorate.

[0040] FIG. 1 is a graph showing the peel strength at high temperature and high temperature and high humidity of the pressure-sensitive adhesive film for a non-metallic substrate when the content of the alicyclic group-containing (meth)acrylic monomer in the monomer mixture is changed. FIG. 2 is a graph showing the peel strength at high temperature and high temperature and high humidity of the pressure-sensitive adhesive film for a metallic substrate when the content of the alicyclic group-containing (meth)acrylic monomer in the monomer mixture is changed.

[0041] Referring to FIGS. 1 and 2, it can be confirmed that when the alicyclic group-containing (meth)acrylic monomer is contained in the monomer mixture in an amount of 1% to 10% by weight, the peel forces at high temperature and high temperature and high humidity with respect to the metal-based substrate and the non-metal-based substrate are significantly increased, respectively.

[0042] FIGS. 1 and 2 show the peel forces of the pressure-sensitive adhesive film according to one embodiment with respect to the non-metal-based substrate and the metal-based substrate.

[0043] The alicyclic group-containing (meth)acrylic monomer may be a (meth)acrylate having an alicyclic group having 5 to 10 carbon atoms in the ester moiety (where the alicyclic group is a cyclic functional group consisting of only carbon and hydrogen). For example, the (meth)acrylate may be one or more of cyclohexyl acrylate and cyclohexyl methacrylate, preferably cyclohexyl acrylate.

[0044] The monomer mixture may further contain a (meth)acrylic monomer having a glass transition temperature of the homopolymer of -40°C or lower, for example, -80°C to -40°C. The (meth)acrylic monomer having a glass transition temperature of the homopolymer of -40°C or lower, for example, -80°C to -40°C, prevents the storage modulus of the pressure-sensitive adhesive film from becoming too high due to the alicyclic group-containing (meth)acrylic monomer, and the pressure-sensitive adhesive film can easily maintain an appropriate modulus.

[0045] According to one embodiment, the (meth)acrylic monomer having a glass transition temperature of the homopolymer of -40°C or lower may be a (meth)acrylate having a linear or branched alkyl group having 1 to 20 carbon atoms in the ester moiety. Specifically, the (meth)acrylate may include one or more of butyl (meth)acrylates such as n-butyl (meth)acrylate, pentyl (meth)acrylates such as n-pentyl (meth)acrylate, hexyl (meth)acrylates such as n-hexyl (meth)acrylate, heptyl (meth)acrylates such as n-heptyl (meth)acrylate, octyl (meth)acrylates such as n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylates such as n-nonyl (meth)acrylate, and decyl (meth)acrylates such as n-decyl (meth)acrylate.

[0046] The (meth)acrylic monomer having a glass transition temperature of the homopolymer of -40°C or lower may be contained in the monomer mixture in an amount of 60% to 90% by weight, for example, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90 wt%, 60% by weight, or 60% to 80% by weight. Within this range, the peel force of the adhesive film can be provided, and the adhesive film can provide an appropriate modulus.

[0047] According to one embodiment, as the (meth)acrylic monomer having a glass transition temperature of the homopolymer of -40°C or lower, a mixture of a (meth)acrylate having a linear alkyl group having 1 to 20 carbon atoms and a (meth)acrylate having a branched alkyl group having 1 to 20 carbon atoms can be used.

[0048] In one embodiment, each of the (meth)acrylic acid ester having a linear alkyl group with 1 to 20 carbon atoms and the (meth)acrylic acid ester having a branched alkyl group with 1 to 20 carbon atoms can be selected and used from the (meth)acrylic acid esters having the above-listed alkyl groups with 1 to 20 carbon atoms. For example, the (meth)acrylic acid ester having a linear alkyl group with 1 to 20 carbon atoms may be n-propyl (meth)acrylate, n-butyl (meth)acrylate, etc. The (meth)acrylic acid ester having a branched alkyl group with 1 to 20 carbon atoms may be 2-ethylhexyl (meth)acrylate, etc.

[0049] In one embodiment, the (meth)acrylic acid ester having a linear alkyl group with 1 to 20 carbon atoms is 10 wt% to 50 wt% in the monomer mixture, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 wt%, or may be 10 wt% to 30 wt%. The (meth)acrylic acid ester having a branched alkyl group with 1 to 20 carbon atoms is 50 wt% to 90 wt% in the monomer mixture, for example, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90 wt%, or may be 50 wt% to 80 wt%. Within the above range, the effects of the pressure-sensitive adhesive film of the present application can be easily achieved.

[0050] The monomer mixture may further contain a (meth)acrylic monomer having a crosslinkable functional group. The (meth)acrylic monomer having the crosslinkable functional group can easily increase the peel strength of the pressure-sensitive adhesive film. The crosslinkable functional group may be one or more of a hydroxyl group, an amino group, an epoxy group, and a carboxylic acid group. Preferably, the crosslinkable functional group may be a hydroxyl group.

[0051] The (meth)acrylic monomer having a hydroxyl group may include one or more of a (meth)acrylic monomer having an alkyl group having 1 to 20 carbon atoms with a hydroxyl group, a (meth)acrylic monomer having a cycloalkyl group having 3 to 20 carbon atoms with a hydroxyl group, and a (meth)acrylic monomer having an aromatic group having 6 to 20 carbon atoms with a hydroxyl group. Specifically, the (meth)acrylic monomer having a hydroxyl group can include, as a (meth)acrylic monomer having an alkyl group having 1 to 20 carbon atoms with a hydroxyl group, one or more of 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate. These can be included alone or in a mixture of two or more.

[0052] The (meth)acrylic monomer having a hydroxyl group is 5% to 40% by weight, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40% by weight, 5% to 35% by weight, or 10% to 35% by weight in the monomer mixture. Within the above range, the effects of the pressure-sensitive adhesive film of the present application can be easily achieved.

[0053] According to one embodiment, in the monomer mixture, the total of the alicyclic group-containing (meth)acrylic monomer, the (meth)acrylic monomer having a glass transition temperature of the homopolymer of -40°C or lower, and the (meth)acrylic monomer having a hydroxyl group may be contained in the monomer mixture at 98% by weight or more, for example, 99% to 100% by weight, or 100% by weight. Within this range, the effects of the pressure-sensitive adhesive film of the present application can be easily achieved.

[0054] The (meth)acrylic binder may have a weight average molecular weight (Mw) of 500,000 g / mol to 2,000,000 g / mol, for example, 500,000, 600,000, 700,000, 800,000, 900,000, 1,000,000, 1,100,000, 1,200,000, 1,300,000, 1,400,000, 1,500,000, 1,600,000, 1,700,000, 1,800,000, 1,900,000, 2,000,000 g / mol, or 900,000 g / mol to 1,500,000 g / mol. Within this range, the effects of the pressure-sensitive adhesive film of the present application can be easily achieved.

[0055] The (meth)acrylic binder may have a glass transition temperature (Tg) of -35°C or lower, for example, -60, -59, -58, -57, -56, -55, -54, -53, -52, -51, -50, -49, -48, -47, -46, -45, -44, -43, -42, -41, -40, -39, -38, -37, -36, -35°C, or -60°C to -35°C. Within this range, the effects of the pressure-sensitive adhesive film of the present application can be easily achieved.

[0056] In one embodiment, the (meth)acrylic binder can be produced by polymerizing the monomer mixture by a conventional polymerization method. The polymerization method can include conventional methods known to those skilled in the art. For example, the (meth)acrylic binder can be produced by adding an initiator to the monomer mixture and then performing conventional copolymerization, such as suspension polymerization, emulsion polymerization, solution polymerization, etc. The polymerization temperature may be 65°C to 70°C, and the polymerization time may be 6 hours to 8 hours. As the initiator, a conventional one including an azo-based polymerization initiator; and / or a peroxide such as benzoyl peroxide or acetyl peroxide can be used.

[0057] The thermosetting agent can cure the (meth)acrylic binder to facilitate the formation of the matrix of the pressure-sensitive adhesive film and increase the peel strength of the pressure-sensitive adhesive film.

[0058] The thermosetting agent can include one or more of an isocyanate-based curing agent, a metal chelate-based curing agent, an epoxy-based curing agent, an amine-based curing agent, and an aziridine-based curing agent.

[0059] The isocyanate-based curing agent can include a bifunctional to hexafunctional isocyanate-based curing agent. Specifically, the isocyanate-based curing agent includes one or more aromatic isocyanate-based curing agents such as toluene diisocyanate, xylylene diisocyanate, halogen-substituted toluene diisocyanate, phenylenediisocyanate such as m-phenylenediisocyanate, tetramethyl-xylylene diisocyanate; one or more aliphatic isocyanate-based curing agents such as hexamethylene diisocyanate, pentamethylene diisocyanate; an alicyclic isocyanate-based curing agent such as cyclohexamethylene diisocyanate; or an adduct thereof, for example, an adduct of a polyol such as trimethylolpropane (TMP) and the above-mentioned curing agent.

[0060] The metal chelate-based curing agent can include metal chelate-based crosslinking agents commonly used by those skilled in the art as crosslinking agents composed of metal-chelate bonds. In one embodiment, the metal chelate-based crosslinking agent can include crosslinking agents having two or more, for example, 3 to 6 metal-chelate bonds. For example, the metal can include aluminum, zirconium, titanium, cobalt, preferably aluminum. For example, the chelate can include acetylacetonate, ethyl acetoacetate, etc., but is not limited thereto. Specifically, the metal chelate-based crosslinking agent can include one or more of aluminum acetylacetonate, aluminum tris(acetylacetonate), aluminum tris(ethyl acetoacetate), aluminum bis(acetoacetate), zirconium tris(acetylacetonate), cobalt tris(acetylacetonate), but is not limited thereto.

[0061] Preferably, the thermosetting agent can use a mixture of an isocyanate-based curing agent and a metal chelate-based curing agent. The mixture can enable the composition containing the above-mentioned (meth)acrylic binder to easily exhibit the effects of the present application. In one embodiment, the weight ratio of the isocyanate-based curing agent to the metal chelate-based curing agent can be 1:0.1 to 1:3, for example, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.0, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2.0, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3, 1:0.5 to 1:2, 1:1 to 1:2. Within the above range, the composition containing the above-mentioned (meth)acrylic binder can easily exhibit the effects of the present application.

[0062] The thermosetting agent may be included in an amount of 0.01 to 1 part by weight, for example, 0.01 to 0.5 part by weight or 0.01 to 0.1 part by weight, based on 100 parts by weight of the (meth)acrylic binder. Within the above range, it is possible to easily achieve improvement in the peel strength of the pressure-sensitive adhesive film, shear deformation rate, and storage modulus.

[0063] The composition, that is, the pressure-sensitive adhesive film, may further contain a silane coupling agent.

[0064] The silane coupling agent can further increase the peel strength of the pressure-sensitive adhesive film. The silane coupling agent can include ordinary silane coupling agents known to those skilled in the art. For example, the silane coupling agent can include epoxy group-containing silane coupling agents such as glycidoxypropyltrimethoxysilane and glycidoxypropylmethyldimethoxysilane, but is not limited thereto.

[0065] The silane coupling agent may be included in an amount of 0.01 to 5 parts by weight, for example, 0.01 to 0.1 part by weight, based on 100 parts by weight of the (meth)acrylic binder. Within the above range, the effect of improving the peel strength can be achieved.

[0066] According to one embodiment, the composition may be a solvent-free type that does not contain a solvent.

[0067] According to another embodiment, the composition may further contain a solvent. The solvent can make the surface of the pressure-sensitive adhesive film uniform when producing a thin pressure-sensitive adhesive film from the composition. The solvent can be used without limitation as ordinary solvents known to those skilled in the art. For example, the solvent may be ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, etc. as organic solvents, but is not limited thereto. The composition may have a solid content of 50% by weight or less, for example, 20% by weight or less.

[0068] The composition, i.e., the adhesive film, can further contain additives. The additives can provide additional functions to the adhesive film. Specifically, the additives can include, but are not limited to, one or more of a UV absorber, a reaction inhibitor, an adhesion improver, a thixotropic agent, a conductivity-imparting agent, a pigment regulator, a stabilizer, an antioxidant, a leveling agent, and an antistatic agent. The content of the additives in the composition, i.e., the adhesive film, can be appropriately selected within a range that does not affect the effects of the present invention.

[0069] The adhesive film may have a haze of 1% or less, for example, 0% to 1% in the visible light region, for example, at a wavelength of 380 nm to 780 nm. Within this range, it can be used for an optical display device.

[0070] The adhesive film may have a thickness of 35 μm or less, for example, more than 0 μm and 35 μm or less, or 5 μm to 15 μm. Within this range, it can be applied to an optical display device.

[0071] According to one embodiment, the adhesive film may not contain organic nanoparticles. Here, the "organic nanoparticles" may be organic nanoparticles known for providing conventional holding properties, such as core-shell nanoparticles. The adhesive film can provide excellent holding properties even without containing organic nanoparticles.

[0072] The adhesive film may be formed of the above-described composition for an adhesive film. Specifically, the adhesive film can be manufactured by applying the composition for an adhesive film to a release film and then thermally curing it. The thermal curing can be performed by heat treatment at 80°C to 100°C for 1 minute to 30 minutes, but is not limited thereto.

[0073] According to one embodiment, the optical member includes a non-metallic base material, an adhesive film, and a metallic base material laminated in this order. The adhesive film includes a cured product of a composition containing a (meth)acrylic binder and a curing agent. The (meth)acrylic binder is a (meth)acrylic binder of a monomer mixture containing 1% to 10% by weight of an alicyclic group-containing (meth)acrylic monomer.

[0074] Referring to FIG. 3, the optical member can include a non-metallic base material 10, an adhesive film 20, and a metallic base material 30 laminated in this order.

[0075] Since the non-metallic base material, the adhesive film, and the metallic base material are substantially the same as those described above, detailed description thereof is omitted.

[0076] In one embodiment, the optical element provides certain optical functions in an optical display device, such as polarization, optical compensation, improvement of display image quality, and / or conductivity. The optical film can include a window film, a window, a polarizing plate, a color filter, a retardation film, an elliptical polarization film, a reflective polarization film, an anti-reflection film, a compensation film, a brightness enhancement film, an alignment film, a light diffusion film, a glass splash prevention film, a surface protection film, an OLED element barrier layer, a plastic LCD substrate, a transparent electrode film including ITO (indium tin oxide), FTO (fluorinated tin oxide), AZO (aluminum dopped zinc oxide), CNT (carbon nanotube), Ag nanowire, graphene, etc.

[0077] The optical member may be a three-layer optical member including a non-metallic base material, an adhesive film, and a metallic base material. Alternatively, the optical member may include two or more non-metallic base materials, two or more adhesive films, and two or more metallic base materials.

[0078] According to one embodiment, the optical display device includes the adhesive film or the optical member.

[0079] The optical display device can include a light-emitting element display device such as an organic light-emitting element display device, a liquid crystal display device, etc. The optical display device can include a flexible display device. However, the optical display device may include a non-flexible display device.

Example

[0080] Hereinafter, the configuration and operation of the present invention will be described in more detail through examples of the present invention. However, the following examples are for helping the understanding of the present invention, and the scope of the present invention is not limited to the following examples.

[0081] Example 1 100 parts by weight of a monomer mixture composed of 2-ethylhexyl acrylate (2-EHA), n-butyl acrylate (n-BA), 4-hydroxybutyl acrylate (4-HBA), and cyclohexyl acrylate (CHA) was charged into a 1 L reactor with nitrogen gas refluxing and a cooling device provided. Then, 100 parts by weight of ethyl acetate was charged as a solvent. In order to remove oxygen, after sufficiently purging with nitrogen gas, the temperature was maintained at 60 °C, 0.03 parts by weight of azobisisobutyronitrile as a polymerization initiator was charged, and the reaction was carried out for 12 hours. After the reaction, it was diluted with ethyl acetate to prepare a solution containing a (meth)acrylic binder (glass transition temperature: -54 °C, weight average molecular weight: 1.2 million g / mol).

[0082] To the solution obtained above, based on 100 parts by weight of the solid content of the (meth)acrylic binder, 0.03 parts by weight of an isocyanate-based curing agent Coronate-L (TOSOH Corporation), 0.03 parts by weight of a metal chelate-based curing agent CK-401E (NCI Corporation, an aluminum-containing trifunctional curing agent), and 0.05 parts by weight of 3-glycidoxypropyltrimethoxysilane KBM-403 (Shinetsu Corporation) as a silane coupling agent were mixed to prepare a composition for an adhesive film with a solid content of 20 wt%.

[0083] The composition for the pressure-sensitive adhesive film produced was applied to a first release PET (polyethylene terephthalate) film, which is a release film, with a predetermined thickness and dried to form a coating film with a thickness of 15 μm. After covering the coating film with a second release PET film, it was dried (thermally cured) at 100 °C for 3 minutes to produce a pressure-sensitive adhesive sheet of first release PET film - pressure-sensitive adhesive film (thickness: 15 μm) - second release PET film.

[0084] Examples 2 to 4 In Example 1, the pressure-sensitive adhesive film composition and the pressure-sensitive adhesive sheet were produced in the same manner as in Example 1, except that the contents of the respective components in the pressure-sensitive adhesive film composition were changed as shown in Table 1 below.

[0085] Comparative Examples 1 to 4 In Example 1, the pressure-sensitive adhesive film composition and the pressure-sensitive adhesive sheet were produced in the same manner as in Example 1, except that the contents of the respective components in the pressure-sensitive adhesive film composition were changed as shown in Table 1 below.

[0086] The configurations of the pressure-sensitive adhesive films of the examples and comparative examples are shown in Table 1 below. The physical properties shown in Table 1 below were evaluated for the pressure-sensitive adhesive films of the examples and comparative examples.

[0087] (1) Peel force at high temperature on PET film (unit: gf / inch): The adhesive sheets of the examples and comparative examples were cut into horizontal × vertical (100 mm × 25 mm). Then, the first release film was peeled off, a PET (polyethylene terephthalate) film (not corona-treated) was laminated, and after peeling off the second release film, it was laminated on a PET (polyethylene terephthalate) film (corona-treated), and a specimen was produced by attaching it with a 2 kg hand roller. With the above-produced specimen, in a chamber with a peeling temperature of 60 °C, at a peeling angle of 180° and a peeling speed of 300 mm / min, the peel force when peeling the laminate of the adhesive film and the PET (polyethylene terephthalate) film (corona-treated) from the PET (polyethylene terephthalate) film (not corona-treated) was measured. The peel force was measured using a TA.XT_Plus Texture Analyzer (manufactured by Stable Micro System).

[0088] (2) Peel force at high temperature and high humidity on PET film (unit: gf / inch): Specimens were produced in the same manner as (1). The peel force was measured in the same manner as for the produced specimens in a chamber with a peeling temperature of 60 °C and a peeling relative humidity of 93%.

[0089] (3) Peel force at high temperature on a metal plate (unit: gf / inch): The adhesive sheets of the examples and comparative examples were cut into horizontal × vertical (100 mm × 25 mm). Then, the first release film was peeled off, the surface of the peeled adhesive film was laminated on a SUS metal plate, and after peeling off the second release film, a PET (polyethylene terephthalate) film (not corona-treated) was laminated, and a specimen was produced by attaching it with a 2 kg hand roller. For the produced specimen, the same method as (1) was applied, but the peel force when peeling the laminate of the adhesive film and the PET (polyethylene terephthalate) film (not corona-treated) from the SUS metal plate was measured.

[0090] (4) Peel force at high temperature and high humidity for the metal plate (unit: gf / inch): Specimens were produced in the same manner as in (3). For the produced specimens, the peel force was measured in the same manner within a chamber at a peel temperature of 60 °C and a peel relative humidity of 93%.

[0091] (5) Shear deformation rate (unit: %): The PET films on both sides were released from the pressure-sensitive adhesive sheets of the examples and comparative examples to obtain pressure-sensitive adhesive films (length × width: 100 mm × 25 mm). A plurality of pressure-sensitive adhesive films were laminated, and the laminate was perforated with a punching machine having a diameter of 8 mm to produce cylindrical specimens (thickness: 500 μm, diameter: 8 mm) having an upper surface and a lower surface.

[0092] The upper surface and the lower surface of the produced cylindrical specimens were mounted so as to be engaged with the upper jig and the lower jig of a dynamic viscoelasticity measuring device rheometer (TA Instruments, DHR3), respectively. The chamber temperature was set to 60 °C, Axial force to 1 N, and Torque to 2 kPa, the time was specified as 600 seconds, and the measurement was performed under the conditions of 600-second stress and 600-second release. The deformation rate value at 600-second stress was taken as the shear deformation rate.

[0093] (6) Storage modulus (unit: MPa): Using a rheometer (TA Instruments, dhr3) of a dynamic viscoelasticity measuring device, the storage modulus was measured under auto strain conditions at a shear rate of 1 rad / sec and a strain of 1%. A plurality of pressure-sensitive adhesive films produced in the examples and comparative examples were laminated to prepare a sample having a thickness of 500 μm. The laminate was perforated with a punching machine having a diameter of 8 mm and used as a specimen. Using an 8-mm jig, the measurement was performed in a temperature sweep test mode on the specimen while increasing the temperature at a rate of 5 °C / min from -50 °C to 100 °C with a normal force of 1.0 N applied, and the storage modulus was determined at -20 °C and 60 °C.

[0094] (7) Holding property: The double-sided release films were separated from the pressure-sensitive adhesive sheets manufactured in the examples and comparative examples, respectively, to obtain pressure-sensitive adhesive films. One side of the pressure-sensitive adhesive film was brought into contact with the corona-treated surface of a 50-μm-thick polyethylene terephthalate (PET) film that had been corona-treated, and the other side of the pressure-sensitive adhesive film was brought into contact with a SUS metal plate. After that, it was adhered with a roller and aged at room temperature for 12 hours, and then cut into a size of 70 mm × 140 mm (width × length) to produce test pieces. The cut test pieces were fixed to a flexibility evaluation equipment (CFT-200, Covotech) using an adhesive (4965, Tesa), and at 60°C and a relative humidity of 93%, the longitudinal direction (140 mm) of the test piece was bent at a speed of 30 cycles per minute so that the radius of curvature became 3 mm (one cycle is defined as bending or stretching the pressure-sensitive adhesive film in half once). When bending was repeated for one cycle, the number of cycles at which cracks first occurred in the polyethylene terephthalate film was measured with the naked eye. A pressure-sensitive adhesive film with a large minimum number of cycles means that it can easily relieve the stress on the polyethylene terephthalate film and SUS metal plate due to bending. If the number of initial cycles is 100,000 or more, it is considered OK; if it is less than 100,000, it is considered NG. The holding property was evaluated at 60°C and a relative humidity of 93%.

[0095]

Table 1

[0096] As shown in Table 1 above, the pressure-sensitive adhesive film according to the present invention has a high peel strength measured against a non-metallic base material at high temperature and high temperature and high humidity, a high peel strength measured against a metallic base material at high temperature and high temperature and high humidity, and provides excellent holding property in the laminated structure of the non-metallic base material, the pressure-sensitive adhesive film, and the metallic base material.

[0097] However, the pressure-sensitive adhesive film of the comparative example could not provide all the effects of the pressure-sensitive adhesive film described in this specification.

[0098] Simple modifications or alterations of the present invention can be easily implemented by those with ordinary knowledge in this field, and all such modifications and alterations can be regarded as being included within the scope of the present invention.

Claims

1. As an adhesive film, The adhesive film is an adhesive film for non-metallic substrates and metallic substrates, The adhesive film has a peel strength of 400 gf / inch or more measured at 60° C. and 93% relative humidity against the non-metallic substrate and the metallic substrate, The pressure-sensitive adhesive film comprises a cured product of a composition comprising a (meth)acrylic binder and a heat curing agent, The (meth)acrylic binder is a (meth)acrylic binder of a monomer mixture containing 1 wt % to 10 wt % of an alicyclic group-containing (meth)acrylic monomer.

2. The pressure-sensitive adhesive film according to claim 1 , wherein the pressure-sensitive adhesive film has a shear deformation rate measured at 60° C. of 15% or more.

3. The pressure-sensitive adhesive film according to claim 1, wherein the pressure-sensitive adhesive film has a storage modulus of 2 MPa or less at -20°C and a storage modulus of 0.5 MPa or less at 60°C.

4. The pressure-sensitive adhesive film according to claim 1, wherein the value of the following formula (1) is 1 or more and the value of the following formula (2) is 1 or more: A2 / A1 (1) (In the above formula (1), A1 is the peel strength (unit: gf / inch) of the adhesive film to a non-metallic substrate at 60°C; A2 is the peel strength (unit: gf / inch) of the adhesive film against a non-metallic substrate at 60°C and 93% relative humidity. B1 / B2 (2) (In the above formula (2), B1 is the peel strength (unit: gf / inch) of the adhesive film to a metal substrate at 60 ° C.; B2 is the peel strength (unit: gf / inch) of the pressure-sensitive adhesive film to a metal substrate at 60° C. and 93% relative humidity.

5. The pressure-sensitive adhesive film according to claim 1 , wherein the alicyclic group-containing (meth)acrylic monomer comprises at least one of cyclohexyl acrylate and cyclohexyl methacrylate.

6. The pressure-sensitive adhesive film according to claim 1 , wherein the monomer mixture further contains a (meth)acrylic monomer having a homopolymer glass transition temperature of −40° C. or lower.

7. The (meth)acrylic monomer having a homopolymer glass transition temperature of -40°C or less is a (meth)acrylic acid ester having a linear or branched alkyl group having 1 to 20 carbon atoms at the ester moiety. The pressure-sensitive adhesive film according to claim 6.

8. The pressure-sensitive adhesive film according to claim 6, wherein the (meth)acrylic monomer having a homopolymer glass transition temperature of −40° C. or lower is contained in the monomer mixture in an amount of 60% by weight to 90% by weight.

9. The pressure-sensitive adhesive film according to claim 6 , wherein the monomer mixture further contains a (meth)acrylic monomer having a hydroxyl group.

10. The pressure-sensitive adhesive film according to claim 9, wherein the total content of the alicyclic group-containing (meth)acrylic monomer, the (meth)acrylic monomer having a homopolymer glass transition temperature of -40°C or lower, and the (meth)acrylic monomer having a hydroxyl group is 98% by weight or more in the monomer mixture.

11. The pressure-sensitive adhesive film according to claim 1 , wherein the heat curing agent is a mixture of an isocyanate-based curing agent and a metal chelate-based curing agent.

12. A non-metallic substrate, an adhesive film, and a metallic substrate are laminated in this order, The pressure-sensitive adhesive film comprises a cured product of a composition comprising a (meth)acrylic binder and a heat curing agent, and the (meth)acrylic binder is a (meth)acrylic binder of a monomer mixture containing 1 wt % to 10 wt % of an alicyclic group-containing (meth)acrylic monomer.

13. The optical member according to claim 12 , wherein the non-metallic substrate is a polymer film.

14. The optical member according to claim 12 , wherein the pressure-sensitive adhesive film has a shear deformation rate measured at 60° C. of 15% or more.

15. The optical member according to claim 12, wherein the pressure-sensitive adhesive film has a storage modulus of 2 MPa or less at -20°C and a storage modulus of 0.5 MPa or less at 60°C.

16. The optical member according to claim 12, wherein the monomer mixture further contains a (meth)acrylic monomer having a homopolymer glass transition temperature of −40° C. or lower.

17. 13. The optical member according to claim 12, wherein the (meth)acrylic monomer having a homopolymer glass transition temperature of −40° C. or lower is contained in the monomer mixture in an amount of 60% by weight to 90% by weight.

18. The optical member according to claim 17 , wherein the monomer mixture further contains a (meth)acrylic monomer having a hydroxyl group.

19. The optical member according to claim 18, wherein a total of the alicyclic group-containing (meth)acrylic monomer, the (meth)acrylic monomer having a homopolymer glass transition temperature of −40° C. or lower, and the (meth)acrylic monomer having a hydroxyl group is contained in the monomer mixture at 98% by weight or more.

20. An optical display device comprising the pressure-sensitive adhesive film according to any one of claims 1 to 11 or the optical member according to any one of claims 12 to 19.

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