Adhesive film and optical display device including same

Abstract

An adhesive film and an optical display device including the same are provided. The adhesive film includes a first region and a second region having different storage moduli, where the first region and the second region satisfy relational expression 1 and relational expression 2: 0.01 < = G '(25 DEG C / B) / G' (25 DEG C / A) < = 0.2,-(relational expression 1) 0.1 < = G '(60 DEG C / B) / G' (60 DEG C / A) < = 0.5,-(relational expression 2) where G '(25 DEG C / A) represents the storage modulus of the first region at 25 DEG C, and G' (25 DEG C / B) represents the storage modulus of the second region at 25 DEG C; and G '(60 DEG C / A) represents the storage modulus of the first region at 60 DEG C, and G' (60 DEG C / B) represents the storage modulus of the second region at 60 DEG C.

Description

[0001] Cross-reference of related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2024-0148510, filed on October 28, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention relates to an adhesive film and an optical display device comprising the adhesive film. Background Technology

[0004] Optical display devices may include display elements such as a window film, a touch pad, a conductive film, and an organic light-emitting device. The touch pad may have a structure in which a transparent adhesive layer (optically clear adhesive, OCA) is sandwiched between the window film and the conductive film. The transparent adhesive layer may also be sandwiched between two of the window film, conductive film, polarizer, and organic light-emitting device. Recently, flexible displays have been developed and have attracted significant attention as optical display devices.

[0005] Flexible displays require flexibility in their various optical components. Because a transparent adhesive layer is formed between the window film and the conductive film, the transparent adhesive layer must have good adhesion on both sides. Furthermore, the transparent adhesive layer must possess good flexibility and foldability. For example, a flexible display may include bendable areas where bending occurs and non-bendable areas where bending is not required. Generally, bendable areas refer to the areas of the flexible display where the user folds the display. Non-bendable areas are located around and / or along the bendable areas, and may refer, for example, to the areas of the flexible display where the user holds the display. Bendable areas require good flexibility and foldability. In non-bendable areas, the transparent adhesive layer should not be compressed, and the organic light-emitting device panel should not be damaged and / or deformed. Summary of the Invention

[0006] One or more aspects of embodiments of this disclosure relate to an adhesive film having good rollability and impact resistance. Additional aspects will be set forth in part in the description which follows, and will be apparent in part from the description, or may be learned by practicing the embodiments presented in this disclosure.

[0007] According to one or more embodiments of the present disclosure, an adhesive film is provided.

[0008] The adhesive membrane includes a first region and a second region with different storage moduli, wherein the first region and the second region satisfy Relation 1 and Relation 2:

[0009] 0.01 ≤ G'(25°C / B) / G'(25°C / A) ≤ 0.2, --- (Equation 1)

[0010] Where G'(25°C / A) represents the energy storage modulus of the first region at 25°C, and G'(25°C / B) represents the energy storage modulus of the second region at 25°C; and

[0011] 0.1 ≤ G'(60°C / B) / G'(60°C / A) ≤ 0.5, --- (Equation 2)

[0012] Where G'(60°C / A) represents the energy storage modulus of the first region at 60°C, and G'(60°C / B) represents the energy storage modulus of the second region at 60°C.

[0013] According to one or more embodiments of the present disclosure, an optical display device is provided.

[0014] Optical display devices include adhesive films.

[0015] Therefore, embodiments of this disclosure provide an adhesive film that exhibits good properties in terms of both rollability and impact resistance. Attached Figure Description

[0016] The accompanying drawings are included to provide a further understanding of this disclosure and are incorporated in and constitute a part of this disclosure. The drawings illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure. The above and other aspects, features, and benefits of this disclosure will become more apparent to those skilled in the art through the following exemplary embodiments, which are described in detail with reference to the accompanying drawings.

[0017] Figure 1 This is a cross-sectional view of an adhesive film according to one or more embodiments of the present disclosure.

[0018] Figure 2 (a) is a diagram of an adhesive film in a post-rollable state according to one or more embodiments of the present disclosure.

[0019] Figure 2 (b) is a diagram of the adhesive film in a pre-rollable state according to one or more embodiments of the present disclosure.

[0020] Figure 3 This is a schematic diagram illustrating the evaluation of rollable reliability according to one or more embodiments of the present disclosure. Detailed Implementation

[0021] In the following description, exemplary embodiments of this disclosure will be given in detail with reference to the accompanying drawings, enabling those skilled in the art to readily implement and understand this disclosure. It should be understood that this disclosure can be implemented in various ways and is not limited to the following embodiments. In the drawings, for clarity, parts unrelated to or unnecessary to this disclosure will not be provided, and the same components will be indicated by the same reference numerals throughout the disclosure.

[0022] In this document, spatially relative terms such as “upper” and “lower” are defined with reference to the accompanying drawings. Therefore, it should be understood that the term “upper surface” is used interchangeably with the term “lower surface.” When an element such as a layer or membrane is referred to as being placed “on” another element, it may be placed directly on the other element, or one or more intervening elements may be present between them. Conversely, when an element is referred to as being placed “directly” on another element, no intervening element is present between them.

[0023] In this article, "(meth)acryl" refers to acryl and / or methacryl.

[0024] In this document, "copolymer" may include oligomers, polymers, or resins.

[0025] One or more embodiments of this disclosure provide an adhesive film with good rollability and impact resistance. The adhesive film includes a first region and a second region, which are described below, wherein the first region and the second region are integrally formed with each other (e.g., laterally integral) to form a monolayer and have good rollability and impact resistance. Therefore, the adhesive film can be used in rollable display devices.

[0026] The adhesive films according to one or more embodiments of the present disclosure will now be described in more detail.

[0027] The adhesive film contains regions with different storage moduli within a single plane. For example, the adhesive film includes a first region and a second region, wherein the first region and the second region have different storage moduli at the same measurement temperature.

[0028] Figure 1 This is a cross-sectional view of an adhesive film according to one or more embodiments of the present disclosure. Figure 2(a) is a diagram of the adhesive film in a rolled-up state according to one or more embodiments of the present disclosure. Figure 2 (b) is a diagram of the adhesive film according to one or more embodiments of the present disclosure in its state before curling. (Refer to...) Figure 1 and Figure 2 The adhesive film includes a first region 100 and a second region 200, wherein the first region 100 and the second region 200 are integrally formed with each other (e.g., laterally integrally).

[0029] Reference Figure 1 In one or more embodiments, the adhesive film comprises two regions in total, in the order of a first region 100 and a second region 200 on the outermost surface of the adhesive film in its longitudinal direction, wherein one outermost surface of the adhesive film in the transverse direction constitutes the first region 100, and the other outermost surface of the adhesive film in the transverse direction constitutes the second region 200.

[0030] The first and second regions satisfy relations 1 and 2:

[0031] 0.01 ≤ G'(25°C / B) / G'(25°C / A) ≤ 0.2, --- (Equation 1)

[0032] Where G'(25°C / A) represents the energy storage modulus of the first region at 25°C, and G'(25°C / B) represents the energy storage modulus of the second region at 25°C; and

[0033] 0.1 ≤ G'(60°C / B) / G'(60°C / A) ≤ 0.5, --- (Equation 2)

[0034] Where G'(60°C / A) represents the energy storage modulus of the first region at 60°C, and G'(60°C / B) represents the energy storage modulus of the second region at 60°C.

[0035] Equations 1 and 2 are standards used to determine whether the impact resistance in the first region and the rollability in the second region can be achieved simultaneously. When the adhesive film is applied to a display device, the first region may correspond to a non-rollable region. The second region may correspond to a rollable region. Although the first region does not have rollability, it is desirable for it to have good impact resistance. On the other hand, it is desirable for the second region to have high rollability. If (for example, when) the second region is formed only on one side of the first region to become rollable, the first region will necessarily be affected by the second region. Through the relationship between the first and second regions as shown in Equations 1 and 2, the adhesive film can achieve the impact resistance of the first region and the rollability of the second region in a balanced manner.

[0036] In one or more embodiments, G'(25°C / B) / G'(25°C / A) may be in the range of, for example, about 0.01 to about 0.2, about 0.05 to about 0.2, about 0.1 to about 0.2, or about 0.15 to about 0.2. In one or more embodiments, G'(25°C / B) / G'(25°C / A) may be about 0.05, about 0.1, about 0.15, or about 0.2.

[0037] In one or more embodiments, G'(60°C / B) / G'(60°C / A) may be in the range of, for example, about 0.1 to about 0.5, about 0.1 to about 0.4, about 0.1 to about 0.3, about 0.1 to about 0.2, about 0.2 to about 0.5, about 0.3 to about 0.5, about 0.4 to about 0.5, or 0.3 to 0.4. In one or more embodiments, G'(60°C / B) / G'(60°C / A) may be, for example, about 0.1, about 0.15, about 0.2, about 0.25, about 0.3, about 0.35, about 0.4, about 0.45, or about 0.5.

[0038] The adhesive film may have a thickness of about 5 μm to about 50 μm (e.g., about 5 μm to about 30 μm).

[0039] According to one or more embodiments, the first region and the second region may each be a pressure-sensitive adhesive film (PSA).

[0040] The first and second regions will now be described in more detail.

[0041] First District

[0042] When the adhesive film is applied to an optical display device, the first region can be located on a non-rollable portion. When the adhesive film is applied to an optical display device, the first region can have good impact resistance to protect the optical components.

[0043] The first region can have a storage modulus of about 0.01 MPa to about 10 MPa at 25°C, for example, about 0.05 MPa, about 0.1 MPa, about 0.15 MPa, about 0.2 MPa, about 0.25 MPa, about 0.3 MPa, about 0.35 MPa, about 0.4 MPa, about 0.45 MPa, about 0.5 MPa, about 0.55 MPa, about 0.6 MPa, about 0.65 MPa, about 0.7 MPa, about 0.75 MPa, about 0.8 MPa, about 0.85 MPa, about 0.9 MPa, about 0.95 MPa, about 1 MPa, or about 0.05 MPa to about 1 MPa or about 0.1 MPa to about 0.8 MPa. Within this range, relation 1 can be easily achieved.

[0044] The first region can have a storage modulus of about 0.005 MPa to about 1 MPa at 60°C, for example, about 0.005 MPa, about 0.01 MPa, about 0.02 MPa, about 0.03 MPa, about 0.04 MPa, about 0.05 MPa, about 0.06 MPa, about 0.07 MPa, about 0.08 MPa, about 0.09 MPa, about 0.1 MPa, about 0.11 MPa, about 0.12 MPa, about 0.13 MPa, about 0.14 MPa, about 0.15 MPa, about 0.16 MPa, about 0.17 MPa, about 0.18 MPa, about 0.19 MPa, about 0.2 MPa, or about 0.01 MPa to about 0.2 MPa or about 0.05 MPa to about 0.1 MPa. Within this range, relation 2 can be easily achieved.

[0045] The first region may exhibit approximately 10% or more creep when measured at 60°C, for example, approximately 10% to approximately 50% or approximately 10% to approximately 40%. Within this range, the adhesive film may exhibit good peel strength and reliability.

[0046] The first region may include a photocurable product of the composition for the first region, wherein the composition may include a monomer mixture and an initiator. In one or more embodiments, the composition for the first region may further include a crosslinking agent. In one or more embodiments, the composition for the first region may further include one or more additives.

[0047] In one or more embodiments, the composition for the first region may include a monomer mixture for a hydroxyl group-containing (meth)acrylic copolymer and an initiator. The monomer mixture may be present in the composition for the first region as a completely unpolymerized monomer mixture or as a partially polymerized polymer.

[0048] The monomer mixture can form a hydroxyl-containing (meth)acrylic acid copolymer. The hydroxyl-containing (meth)acrylic acid copolymer can form the matrix of the first region and exhibit adhesive properties. The hydroxyl-containing (meth)acrylic acid copolymer can have a glass transition temperature of about -100°C to about 10°C, for example, about -70°C to about 0°C. Within this range, the adhesive film exhibits good adhesion and reliability over a wide temperature range. The hydroxyl-containing (meth)acrylic acid copolymer can have a refractive index of about 1.35 to about 1.70, for example, about 1.40 to about 1.60. Within this range, the adhesive film maintains transparency when stacked with other optical films.

[0049] The monomer mixture may include alkyl group-containing (meth)acrylate and alicyclic group-containing (meth)acrylate. The monomer mixture may further include hydroxyl group-containing (meth)acrylate and heterocyclic group-containing vinyl or (meth)acrylic monomer.

[0050] In one or more embodiments, based on 100% by weight of the total weight of the monomer mixture, the total amount of alkyl (meth)acrylate, alicyclic (meth)acrylate, hydroxy (meth)acrylate and heterocyclic vinyl or (meth)acrylate monomers in the monomer mixture may be about 95% by weight or more, for example, about 95% by weight to 100% by weight, or 100% by weight.

[0051] Alkyl (meth)acrylates may include those with unsubstituted C To C Monofunctional (meth)acrylates of straight-chain or branched alkyl groups.

[0052] Alkyl (meth)acrylates may include, for example, 2-ethylhexyl(meth)acrylate, n-butyl(meth)acrylate, iso-octyl(meth)acrylate, propyl(meth)acrylate, t-butyl(meth)acrylate, iso-butyl(meth)acrylate, pentyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate, octyl(meth)acrylate, nonyl(meth)acrylate, and decyl(meth)acrylate. In one or more embodiments, the alkyl (meth)acrylate may include at least one selected from 2-ethylhexyl (meth)acrylate, n-butyl (meth)acrylate, and isooctyl (meth)acrylate. In one or more embodiments, the alkyl (meth)acrylate may include 2-ethylhexyl (meth)acrylate.

[0053] Based on the total weight of the monomer mixture, the amount of alkyl (meth)acrylate in the monomer mixture can be from about 10% by weight to about 80% by weight, for example, about 10% by weight, about 15% by weight, about 20% by weight, about 25% by weight, about 30% by weight, about 35% by weight, about 40% by weight, about 45% by weight, about 50% by weight, about 55% by weight, about 60% by weight, about 65% by weight, about 70% by weight, about 75% by weight, about 80% by weight, or about 30% by weight to about 80% by weight or about 30% by weight to about 50% by weight. Within this range, the adhesive film can achieve further improvements in adhesion and durability.

[0054] Alicyclic (meth)acrylates may include C-terminal groups with substituted or unsubstituted C-terminal groups at their ester positions. To C Alicyclic (meth)acrylates. In one or more embodiments, alicyclic (meth)acrylates may include isobornyl (meth)acrylate.

[0055] Based on the total weight of the monomer mixture, the amount of alicyclic (meth)acrylate in the monomer mixture can be from about 10% by weight to about 60% by weight, for example, about 10% by weight, about 15% by weight, about 20% by weight, about 25% by weight, about 30% by weight, about 35% by weight, about 40% by weight, about 45% by weight, about 50% by weight, about 55% by weight, about 60% by weight, or about 30% by weight to about 40% by weight. Within this range, the adhesive film can achieve further improvements in adhesion and durability.

[0056] Hydroxyl (meth)acrylates can impart adhesive properties to adhesive films. Hydroxyl (meth)acrylates can have a homopolymer glass transition temperature of about 0°C to about -40°C, for example, about -10°C to about -40°C or about -20°C to about -40°C. Within this range, hydroxy (meth)acrylates can improve the adhesive adhesion and flexural reliability of adhesive films.

[0057] Hydroxy(meth)acrylates may be C having at least one hydroxyl group. To C Monofunctional (meth)acrylates of straight-chain or branched alkyl groups. For example, hydroxy (meth)acrylates include at least one selected from 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate.

[0058] Based on the total weight of the monomer mixture, the amount of hydroxy (meth)acrylate in the monomer mixture can be from 0% by weight to about 40% by weight, for example, 0% by weight, about 5% by weight, about 10% by weight, about 15% by weight, about 20% by weight, about 25% by weight, about 30% by weight, about 35% by weight, about 40% by weight, or about 5% by weight to about 40% by weight, about 10% by weight to about 40% by weight, about 10% by weight to about 30% by weight, or about 10% by weight to about 20% by weight. Within this range, the adhesive film can achieve further improvements in adhesion and durability.

[0059] Vinyl or (meth)acrylic monomers containing heterocyclic groups can be C To C A heterocyclic vinyl or (meth)acrylic acid monomer having at least one of oxygen, sulfur, and nitrogen as a ring-forming element. The heterocyclic vinyl or (meth)acrylic acid monomer may include at least one selected from (meth)acryloylmorpholine and vinylpyrrolidone.

[0060] Based on the total weight of the monomer mixture, the amount of heterocyclic vinyl or (meth)acrylic monomers in the monomer mixture can be from 0% to about 30% by weight, for example, 0% by weight, about 5% by weight, about 10% by weight, about 15% by weight, about 20% by weight, about 25% by weight, about 30% by weight, or about 1% by weight to about 30% by weight, about 5% by weight to about 30% by weight, or about 5% by weight to about 10% by weight. Within this range, the adhesive film can achieve further improvements in adhesion and durability.

[0061] In one or more embodiments, the monomer mixture may further include copolymerizable monomers other than those described above. Copolymerizable monomers may include at least one selected from amine group-containing monomers, alkylene glycol group-containing monomers, silane group-containing monomers, and aromatic group-containing monomers.

[0062] Initiators can be used to cure (e.g., partially polymerize) monomer mixtures into (meth)acrylic acid copolymers, or to cure viscous liquids into films. Initiators may include photopolymerization initiators and / or thermal polymerization initiators.

[0063] Photopolymerization initiators can be selected from any typical initiator, provided that the initiator can initiate the polymerization reaction of the aforementioned radical polymerizable compound during curing by light irradiation and / or similar methods. For example, photopolymerization initiators may include benzoin photoinitiators, hydroxy ketone photoinitiators, aminoketone photoinitiators, or phosphine oxide photoinitiators. For instance, photopolymerization initiators may include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, and benzoin isobutyl ether. ether), such as 2,2-dimethoxy-2-phenylacetophenone, 2,2'-diethoxyacetophenone, 2,2'-dibutoxyacetophenone, 2-hydroxy-2-methylpropanone, p-tert-butyltrichloroacetophenone, p-tert-butyldichloroacetophenone, 4-chloroacetophenone, 2,2'-dichloro-4-phenoxyacetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, and 2-hydroxy-2-methyl-1-phenylpropane-1-one, etc., are acetophenone compounds. compound), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propane-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethyl Anthraquinones, including but not limited to 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthiazolinone, 2-ethylthiazolinone, 2-chlorothiazolinone, 2,4-dimethylthiazolinone, 2,4-diethylthiazolinone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligomeric [2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]acetone] and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide. These can be used alone or as mixtures thereof.

[0064] The thermal polymerization initiator can be selected from any typical initiator, such as an azo compound, a peroxide compound, or a redox compound, as long as the initiator has the above-mentioned properties. Examples of azo compounds may include 2,2-azobis(2-methylbutyronitrile), 2,2-triazobis(isobutyronitrile), 2,2-triazobis(2,4-dimethylpentanitrile), 2,2-nitroazobis-2-hydroxymethylpropionitrile, dimethyl-2,2-methylazobis(2-methylpropionate), and 2,2-azobis(4-methoxy-2,4-dimethylpentanitrile); examples of peroxide compounds may include inorganic peroxides such as potassium persulfate, ammonium persulfate, and hydrogen peroxide, as well as organic peroxides such as diacyl peroxides, peroxydicarbonates, peroxy esters, tetramethylbutylperoxyneodecanate, bis(4-butylcyclohexyl)peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, butylperoxyneodecanate, dipropylperoxydicarbonate, diisopropylperoxydicarbonate, diethoxyethylperoxydicarbonate, and di... Ethoxyhexyl peroxydicarbonate, hexyl peroxydicarbonate, dimethoxybutyl peroxydicarbonate, bis(3-methoxy-3-methoxybutyl) peroxydicarbonate, dibutyl peroxydicarbonate, diceryl alcohol peroxydicarbonate, dimyristic acid peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyvalerate, hexyl peroxyvalerate, butyl peroxyvalerate, trimethylhexanoyl peroxide, dimethylhydroxybutyl peroxyneodecanate, pentyl peroxyneodecanate, butyl peroxyneodecanate, tert-butyl peroxyneodecanate, tert-butyl peroxyneoheptanoate, pentyl peroxyvalerate (valerate), tert-butyl peroxyvalerate, tert-pentyl peroxy-2-ethylhexanoate, lauryl peroxide, dilauryl peroxide, didecyl peroxide, benzoyl peroxide and dibenzoyl peroxide (dibenzoyl peroxide) Examples of redox compounds include, but are not limited to, mixtures of peroxides and reducing agents. These azo compounds, peroxides, or redox compounds may be used alone or as mixtures thereof.

[0065] The initiator may be present in an amount from about 0.0001 parts by weight to about 5 parts by weight relative to 100 parts by weight of the monomer mixture, for example, from about 0.001 parts by weight to about 3 parts by weight, or from about 0.001 parts by weight to about 1 part by weight. Within this range, the initiator ensures complete curing of the composition without deteriorating the light transmittance of the adhesive film due to residual initiator, and exhibits good reactivity while inhibiting the formation of bubbles.

[0066] In one or more embodiments, the composition in the first region may further include at least one selected from crosslinking agents and additives.

[0067] Crosslinking agents may include at least one (meth)acrylate selected from bifunctional or higher-functional (meth)acrylates (e.g., (meth)acrylates having two or more functional groups), such as bi- to hexafunctional (meth)acrylates. For example, crosslinking agents may include those such as 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, dicyclopentyl di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified di(meth)acrylate, di(meth)acrylate oxyethyl isocyanurate, allylated cyclohexyl Bifunctional (meth)acrylates include: di(meth)acrylate, tricyclododecanediethanol (meth)acrylate, dimethyl dicyclopentanedi(meth)acrylate, ethylene oxide-modified hexahydrophthalic acid di(meth)acrylate, tricyclodecanediethanol (meth)acrylate, neopentyl glycol-modified trimethylpropane di(meth)acrylate, adamantane di(meth)acrylate, and 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene. (meth)acrylate); such as trifunctional (meth)acrylate, pentaerythritol tri(meth)acrylate, propionic acid modified pentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate and tri(meth)acrylate oxyethyl isocyanurate, etc.; tetrafunctional (meth)acrylate, such as diglycerol tetra(meth)acrylate and pentaerythritol tetra(meth)acrylate; pentafunctional (meth)acrylate, such as pentaerythritol penta(meth)acrylate; and hexafunctional (meth)acrylate, such as pentaerythritol hexa(meth)acrylate and caprolactone modified pentaerythritol hexa(meth)acrylate, etc., selected from, but not limited to, one or more of these.

[0068] The crosslinking agent may be present in an amount of about 0.0001 parts by weight to about 5 parts by weight relative to 100 parts by weight of the monomer mixture, for example, about 0.1 parts by weight to about 5 parts by weight, for example, about 0.5 parts by weight to about 1 part by weight.

[0069] Additives may include silane coupling agents.

[0070] Silane coupling agents can further improve the peel strength of adhesive films. Silane coupling agents may comprise one or more typical silane coupling agents known to those skilled in the art. For example, silane coupling agents may include, but are not limited to, epoxy-containing silane coupling agents such as glycidoxypropyltrimethoxysilane and glycidoxypropylmethyldimethoxysilane.

[0071] The silane coupling agent may be present in an amount of about 0.0001 parts by weight to about 5 parts by weight relative to 100 parts by weight of the monomer mixture, for example, about 0.1 parts by weight to about 5 parts by weight, for example, about 0.5 parts by weight to about 1 part by weight.

[0072] In one or more embodiments, the composition for the first region may further comprise one or more additives other than a silane coupling agent. The additives may comprise, but are not limited to, at least one selected from, UV absorbers, reaction inhibitors, adhesion enhancers, thixotropic imparting agents, conductivity imparting agents, color modifiers, stabilizers, antioxidants, leveling agents, and antistatic agents. The amount of the additive in the composition, i.e., in the first region, may be suitably selected without impairing the effects of this disclosure.

[0073] Second Zone

[0074] When the adhesive film is applied to an optical display device, the second region can be located on the rollable portion. The second region can provide a folding effect when the adhesive film is applied to an optical display device.

[0075] The second region, when measured at 25°C, can have a storage modulus of approximately 0.001 MPa to approximately 1 MPa, for example, approximately 0.001 MPa, approximately 0.01 MPa, approximately 0.02 MPa, approximately 0.03 MPa, approximately 0.04 MPa, approximately 0.05 MPa, approximately 0.06 MPa, approximately 0.07 MPa, approximately 0.08 MPa, approximately 0.09 MPa, approximately 0.1 MPa, or approximately 0.005 MPa to approximately 0.1 MPa or approximately 0.01 MPa to approximately 0.1 MPa. Within this range, relation 1 can be readily achieved.

[0076] The second region, when measured at 60°C, can have a storage modulus of approximately 0.0005 MPa to approximately 0.1 MPa, for example, approximately 0.005 MPa to approximately 0.05 MPa or approximately 0.01 MPa to approximately 0.1 MPa. Within this range, relation 2 can be readily achieved.

[0077] The second region may exhibit approximately 10% or more creep when measured at 60°C, for example, from approximately 10% to approximately 50%. Within this range, the adhesive film can exhibit good peel strength and reliability.

[0078] The second region may contain a photocurable product of the composition for the second region, wherein the composition may contain a monomer mixture and an initiator. In one or more embodiments, the composition for the second region may further contain a crosslinking agent. In one or more embodiments, the composition for the second region may further contain one or more additives.

[0079] The monomer mixture may be present in the composition used in the second region as a completely unpolymerized monomer mixture or as a partially polymerized polymer.

[0080] Monomer mixtures can form hydroxyl (meth)acrylic acid copolymers. These copolymers form the matrix of the second region and exhibit adhesive properties. The hydroxyl (meth)acrylic acid copolymers can have a glass transition temperature from about -100°C to about 10°C, for example, from about -70°C to about 0°C. Within this range, the adhesive film exhibits good adhesion and reliability over a wide temperature range. The hydroxyl (meth)acrylic acid copolymers can have a refractive index from about 1.35 to about 1.70, for example, from about 1.40 to about 1.60. Within this range, the adhesive film maintains transparency when stacked with other optical films.

[0081] The monomer mixture may contain alkyl (meth) acrylates, hydroxy (meth) acrylates and alkylene glycol group-containing (meth) acrylates.

[0082] In one or more embodiments, based on 100% by weight of the total weight of the monomer mixture, the total amount of alkyl (meth)acrylates, hydroxy (meth)acrylates and alkylene glycol (meth)acrylates may be present in the monomer mixture at about 95% by weight or more, for example, about 95% by weight to 100% by weight, or 100% by weight.

[0083] The details of the alkyl (meth)acrylates are substantially the same as those described in the compositions of the first region.

[0084] Based on the total weight of the monomer mixture, the alkyl (meth)acrylate may be present in the monomer mixture in amounts from about 10% by weight to about 80% by weight, for example, about 10% by weight, about 15% by weight, about 20% by weight, about 25% by weight, about 30% by weight, about 35% by weight, about 40% by weight, about 45% by weight, about 50% by weight, about 55% by weight, about 60% by weight, about 65% by weight, about 70% by weight, about 75% by weight, about 80% by weight, or about 40% by weight to about 80% by weight, or about 50% by weight to about 60% by weight. Within this range, the adhesive film can achieve further improvements in adhesion and durability.

[0085] The details of the hydroxy (meth)acrylates are substantially the same as those described in the compositions of the first region.

[0086] Based on the total weight of the monomer mixture, the hydroxyl (meth)acrylate may be present in the monomer mixture in an amount from about 10% by weight to about 40% by weight, for example, about 10% by weight, about 15% by weight, about 20% by weight, about 25% by weight, about 30% by weight, about 35% by weight, about 40% by weight, or about 10% by weight to about 30% by weight or about 10% by weight to about 20% by weight. Within this range, the adhesive film can achieve further improvements in adhesion and durability.

[0087] Alkyl glycol-containing (meth)acrylates may include (meth)acrylates having an alkyl glycol group (e.g., ethylene glycol or propylene glycol) at its ester position. For example, alkyl glycol-containing (meth)acrylates may include at least one selected from 2-ethylhexyl triethylene glycol (meth)acrylate, methoxy triethylene glycol (meth)acrylate, phenoxy triethylene glycol (meth)acrylate, phenoxy diethylene glycol (meth)acrylate, phenoxy polyethylene glycol (meth)acrylate, and phenoxy polyethylene glycol (meth)acrylate.

[0088] Based on the total weight of the monomer mixture, the alkylene glycol (meth)acrylate may be present in the monomer mixture in an amount from about 10% by weight to about 50% by weight, for example, about 10% by weight, about 15% by weight, about 20% by weight, about 25% by weight, about 30% by weight, about 35% by weight, about 40% by weight, about 45% by weight, about 50% by weight, or about 10% by weight to about 40% by weight or about 20% by weight to about 30% by weight. Within this range, the adhesive film can achieve further improvements in adhesion and durability.

[0089] In one or more embodiments, the monomer mixture may further include copolymerizable monomers other than those described above. Copolymerizable monomers may include at least one selected from amino-containing monomers, alkylene glycol-containing monomers, silane-containing monomers, and aromatic monomers.

[0090] The details of the initiator are substantially the same as those described in the composition of the first region.

[0091] The initiator may be present in an amount from about 0.0001 parts by weight to about 5 parts by weight relative to 100 parts by weight of the monomer mixture, for example, from about 0.001 parts by weight to about 3 parts by weight, or from about 0.001 parts by weight to about 1 part by weight. Within this range, the initiator ensures complete curing of the composition without reducing the light transmittance of the adhesive film due to residual initiator, and exhibits good reactivity while inhibiting the formation of bubbles.

[0092] In one or more embodiments, the composition for the second region may further include at least one selected from crosslinking agents and additives.

[0093] The crosslinking agent and additives may be substantially the same as those described in the compositions used in the first region.

[0094] The crosslinking agent may be present in an amount of about 0.0001 parts by weight to about 5 parts by weight relative to 100 parts by weight of the monomer mixture, for example, about 0.1 parts by weight to about 5 parts by weight, for example, about 0.5 parts by weight to about 1 part by weight.

[0095] The silane coupling agent may be present in an amount of about 0.0001 parts by weight to about 5 parts by weight relative to 100 parts by weight of the monomer mixture, for example, about 0.1 parts by weight to about 5 parts by weight, for example, about 0.5 parts by weight to about 1 part by weight.

[0096] Manufacturing adhesive films

[0097] The adhesive film can be manufactured by coating a composition for a first region and a composition for a second region onto a release film at a predetermined thickness to produce a coating for the first region and a coating for the second region, wherein the coating for the first region contacts the coating for the second region. Subsequently, the entire first region coating and the second region coating can be prepared by photocuring at the same intensity.

[0098] An optical display device according to one or more embodiments of the present disclosure includes an adhesive film according to the present disclosure. The optical display device may include organic light-emitting device displays and / or liquid crystal displays, etc. The optical display device may include a flexible display device. However, the optical display device may also include a non-flexible display device.

[0099] The present disclosure will now describe in more detail with reference to examples. However, it should be understood that these examples are provided for illustration only and should not be construed as limiting the present disclosure in any way.

[0100] Example 1

[0101] Preparation of the composition for the first region

[0102] In a reactor, 0.005 parts by weight of Irgacure 651 (2,2-dimethoxy-2-phenylacetophenone, BASF) was used as a photopolymerization initiator and thoroughly mixed with 100 parts by weight of a monomer mixture comprising 40 wt% 2-ethylhexyl acrylate (2-EHA), 40 wt% isobornyl acrylate (IBOA), 10 wt% 4-hydroxybutyl acrylate (4-HBA), and 10 wt% acryloxymorpholine (ACMO). After replacing the dissolved oxygen in the reactor with nitrogen, the mixture was partially polymerized by irradiating it with UV light using a low-pressure mercury lamp (BLLamp, Sankyo) to obtain a solution containing an acrylic copolymer with a viscosity of approximately 1,000 cP.

[0103] To a solution containing an acrylic copolymer, 0.3 parts by weight of Irgacure 651 (2,2-dimethoxy-2-phenylacetophenone, BASF) as a photoinitiator, 1 part by weight of 1,6-hexanedioldiacrylate as a crosslinking agent, and 0.2 parts by weight of 3-glycidoxypropyltriethoxysilane as a silane coupling agent (relative to 100 parts by weight of the monomer mixture) were added, and the mixture was mixed to prepare a composition for the first region.

[0104] Preparation of the composition for the second region

[0105] In a reactor, 0.005 parts by weight of Irgacure 651 (2,2-dimethoxy-2-phenylacetophenone, BASF) was used as a photopolymerization initiator and thoroughly mixed with 100 parts by weight of a monomer mixture comprising 60 wt% 2-ethylhexyl acrylate (2-EHA), 20 wt% 4-hydroxybutyl acrylate (4-HBA), and 20 wt% methoxytriethyleneglycol acrylate (EHDG-AT). The dissolved oxygen in the reactor was then replaced with nitrogen in the same manner. The mixture was then partially polymerized by irradiating it with UV light using a low-pressure mercury lamp (BL Lamp, Sankyo) to obtain a solution containing an acrylic copolymer with a viscosity of approximately 1,000 cP.

[0106] To a solution containing an acrylic copolymer, 0.3 parts by weight of Irgacure 651 (2,2-dimethoxy-2-phenylacetophenone, BASF) as a photoinitiator, 0.1 parts by weight of 1,6-hexanediol diacrylate as a crosslinking agent, and 0.2 parts by weight of 3-glycidyl ether propyltriethoxysilane as a silane coupling agent (relative to 100 parts by weight of the monomer mixture) were added, and the mixture was mixed to prepare a composition for the second region.

[0107] A coating for the first region is prepared by depositing a composition for the first region onto a polyethylene terephthalate (PET) release film to a predetermined thickness, and a coating for the second region is prepared by depositing a composition for the second region along the coating for the first region to the same thickness. The coatings for the first region and the coatings for the second region are formed in a manner that they are in contact with each other side by side.

[0108] The PET film is prepared by attaching a PET film to the entire first and second regions and then irradiating it with UV light at a dose of 2,000 mJ / cm2. The PET film consists of an adhesive film containing the PET film (thickness: 25 μm), an adhesive film containing the first and second regions (thickness: 25 μm), and an adhesive sheet of the PET film.

[0109] Examples 2 to 4

[0110] Except for the changes to the components of the compositions used in the first and second regions as listed in Table 1, each adhesive film was prepared in substantially the same manner as in Example 1.

[0111] Comparative Examples 1 to 5

[0112] Except for the changes to the components of the compositions used in the first and second regions as listed in Table 1, each adhesive film was prepared in substantially the same manner as in Example 1.

[0113] The adhesive layers prepared in the examples and comparative examples were evaluated according to the properties listed in Table 1, and the results are shown in Table 1.

[0114] (1) Energy storage modulus (unit: MPa):

[0115] The viscoelasticity of each of the first and second regions of the adhesive film was measured under auto-strain conditions using a dynamic viscoelasticity measurement device (ARES, Anton Paar, MCR-501) at a shear rate of 1 radians per second (rad / sec) and a strain of 1%. Samples were prepared by stacking each of the first or second regions to a thickness of 500 μm after removing all PET release film from the adhesive sheet, followed by stamping the resulting stacks using a punch press with an 8 mm diameter. For each sample, the storage modulus was measured at 25°C and 60°C under conditions where the temperature increased from -60°C to 90°C at a rate of 5°C / min.

[0116] (2) Impact resistance:

[0117] After peeling the release PET film from each of the adhesive sheets prepared in the examples and comparative examples, a polyurethane film (thickness: 100 μm, cast polyurethane (CPU) with a Young's modulus of 100 MPa at room temperature) was attached to the surface of the adhesive sheet from which the release PET film had been removed. After peeling off the remaining release PET film from the adhesive sheet, a PET film (thickness: 50 μm, TU-94, SKC) was attached to the adhesive sheet, and then the sheets were stacked onto a glass substrate using an acrylic adhesive sheet.

[0118] A pen with a circular cross-section and a diameter of 0.7 mm was dropped vertically from a height onto the first area of ​​a sample stacked in the following order: polyurethane film / adhesive film / PET film / acrylic adhesive sheet / glass substrate. After removing the polyurethane and adhesive films, any indentations on the PET film were examined under a 3D microscope (VK-X1100, KIENS). The height of the first indentation or imprint on the PET film was measured. Heights of 13 cm or higher were rated ◎, heights of 10 cm to less than 13 cm were rated O, heights of 7 cm to less than 10 cm were rated △, and heights of less than 7 cm were rated X.

[0119] (3) Curability:

[0120] From each of the adhesive sheets prepared in the examples and comparative examples, the release PET film was peeled off and a polyurethane film (thickness: 100 μm, CPU with a Young's modulus of 100 MPa at room temperature) was attached to the surface of the adhesive sheet from which the release PET film had been removed. After peeling off the remaining release PET film from the adhesive sheet, a PET film (thickness: 50 μm, TU-94, SKC) was attached to the adhesive sheet to prepare a sample. Here, the polyurethane film was placed on the outermost side of the sample. After placing a circular rod with a diameter of 3 mm at the center of the second region of the adhesive film to act as an axis, the rod was manually rolled by holding the far ends of the first and second regions to repeatedly wind and unwind the sample. Figure 3 A method for evaluating rollability is shown, wherein an adhesive film is prepared comprising a portion 10 corresponding to a first region and a portion 20 corresponding to a second region, and portions 10 and 20 are placed between portions 10 and 20 of the adhesive film by a circular rod 30 and pulled in the same direction.

[0121] No cracks and / or delamination at the boundary between the second and first regions of the adhesive film are rated as ○, while cracks and / or delamination at the boundary between them are rated as X.

[0122] (4) Creep (unit: %):

[0123] A sample with a thickness of 800 μm was prepared by stacking the first region of the adhesive film into multiple layers. The strain of the prepared sample was measured at 60°C under conditions of 1 N (force) and 600 seconds using a DHR rheometer (TA instrument).

[0124] [Table 1]

[0125]

[0126] HEA: 2-hydroxyethyl acrylate

[0127] NVP: N-vinylpyrrolidone

[0128] As shown in Table 1, each of the adhesive films in the examples has good rollability and impact resistance.

[0129] However, the adhesive films of the comparative examples that do not satisfy Relations 1 and 2 have failed to achieve the beneficial effects of this disclosure.

[0130] In this disclosure, the terms “comprise(s) / comprising,” “include(s)k / including,” or “has(have) / having” will be understood to refer to the presence of the stated feature, number, step, operation, element, and / or component, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, components, and / or groups thereof. Furthermore, the terms “consisting of” and “consisting essentially of” indicate the presence of the stated feature, number, step, operation, element, and / or component, without or substantially without the presence of other features, numbers, steps, operations, elements, components, and / or groups thereof.

[0131] As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, the use of “may” in describing embodiments of this disclosure means “one or more embodiments of this disclosure.”

[0132] In this disclosure, when expressions such as “at least one,” “one,” and “selected from” precede a list of elements, they modify the entire list of elements rather than individual elements within the list. For example, “at least one of a, b, and c,” “at least one selected from a, b, and c,” “at least one selected from a to c,” etc., can indicate only a, only b, only c, a and b (e.g., simultaneously), a and c (e.g., simultaneously), b and c (e.g., simultaneously), all of a, b, and c, or variations thereof.

[0133] In this disclosure, although the terms “first,” “second,” etc., may be used herein to describe one or more elements, components, regions, and / or layers, these elements, components, regions, and / or layers should not be limited by these terms. These terms are used only to distinguish one component from another.

[0134] As used herein, the terms “substantially,” “about,” or similar terms are used as approximate terms rather than terms of degree and are intended to take into account the inherent biases in measured or calculated values ​​that would be recognized by those skilled in the art. As used herein, “about” includes the value and indicates that it is within an acceptable range of deviation for a particular value as determined by those skilled in the art, taking into account the relevant measurement and errors associated with the measurement of the particular quantity (i.e., limitations of the measurement system). For example, “about” might mean within one or more standard deviations, or within ±30%, 20%, 10%, or 5% of the value.

[0135] Any numerical range described herein is intended to include all subranges containing the same numerical precision within the stated range. For example, the range “1.0 to 10.0” is intended to include all subranges between (and including) the minimum value of 1.0 and the maximum value of 10.0, i.e., a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, for example, 2.4 to 7.6. Any maximum numerical limit described herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit described in this disclosure is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to modify the disclosure, including the claims, to expressly describe any subranges contained within the range expressly described herein.

[0136] In the context of this disclosure, unless otherwise defined, the terms “use,” “using,” and “used” may be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively.

[0137] The foregoing is an illustration of some embodiments of this disclosure and should not be construed as limiting it. While some embodiments have been described, those skilled in the art will readily understand that various modifications are possible in the embodiments without departing from the spirit and scope of this disclosure. Unless otherwise described, it should be understood that descriptions of features or aspects in each embodiment should generally be considered as applicable to similar features or aspects in other embodiments. Therefore, unless specifically stated otherwise, as will be apparent to those skilled in the art, features, characteristics, and / or elements associated with a particular embodiment may be used alone or in combination with features, characteristics, and / or elements associated with other embodiments. Therefore, it should be understood that the foregoing is an illustration of various exemplary embodiments and should not be construed as limiting to the specific embodiments disclosed herein, and various modifications to the disclosed embodiments and other exemplary embodiments are intended to be included within the spirit and scope of this disclosure, as defined by the appended claims and their equivalents.

Claims

1. An adhesive membrane comprising a first region and a second region having different storage moduli, Wherein the first region and the second region satisfy relation 1 and relation 2: 0.01 ≤ G'(25°C / B) / G'(25°C / A) ≤ 0.2, --- (Equation 1) Where G'(25°C / A) represents the energy storage modulus of the first region at 25°C, and G'(25°C / B) represents the energy storage modulus of the second region at 25°C; and 0.1 ≤ G'(60°C / B) / G'(60°C / A) ≤ 0.5, --- (Equation 2) Where G'(60°C / A) represents the energy storage modulus of the first region at 60°C, and G'(60°C / B) represents the energy storage modulus of the second region at 60°C.

2. The adhesive film according to claim 1, wherein the first region and the second region are integrally formed laterally with each other.

3. The adhesive film according to claim 1, wherein the first region has a storage modulus of 0.01 MPa to 10 MPa at 25°C and a storage modulus of 0.005 MPa to 1 MPa at 60°C.

4. The adhesive film of claim 1, wherein the first region has 10% or more creep at 60°C.

5. The adhesive film according to claim 1, wherein the second region has a storage modulus of 0.001 MPa to 1 MPa at 25°C and a storage modulus of 0.0005 MPa to 0.1 MPa at 60°C.

6. The adhesive film of claim 1, wherein the first region comprises a photocurable product of the composition for the first region, and the composition comprises a monomer mixture and an initiator.

7. The adhesive film according to claim 6, wherein the monomer mixture comprises alkyl (meth)acrylates, alicyclic (meth)acrylates, hydroxy (meth)acrylates, and vinyl or (meth)acrylate monomers containing heterocyclic groups.

8. The adhesive film according to claim 7, wherein, Based on a total weight of 100% by weight of the monomer mixture, the monomer mixture comprises 10% to 80% by weight of the alkyl (meth)acrylate, 10% to 60% by weight of the alicyclic (meth)acrylate, 5% to 40% by weight of the hydroxyl (meth)acrylate, and 1% to 30% by weight of the heterocyclic vinyl or (meth)acrylate monomer.

9. The adhesive film of claim 6, wherein the composition for the first region further comprises at least one selected from a crosslinking agent and a silane coupling agent.

10. The adhesive film of claim 1, wherein the second region comprises a photocurable product of the composition for the second region, and the composition comprises a monomer mixture and an initiator.

11. The adhesive film according to claim 10, wherein the monomer mixture comprises alkyl (meth)acrylates, hydroxy (meth)acrylates, and alkylene glycol (meth)acrylates.

12. The adhesive film according to claim 11, wherein, Based on 100% by weight of the total weight of the monomer mixture, the monomer mixture comprises 10% to 80% by weight of the alkyl (meth) acrylate, 10% to 40% by weight of the hydroxy (meth) acrylate, and 10% to 50% by weight of the alkylene glycol (meth) acrylate.

13. The adhesive film of claim 10, wherein the composition for the second region further comprises at least one selected from a crosslinking agent and a silane coupling agent.

14. The adhesive film of claim 1, wherein the adhesive film comprises a total of two regions on its outermost surface in the longitudinal direction, arranged in the order of the first region and the second region. The adhesive film forms the first region on one outermost surface in the lateral direction, and the adhesive film forms the second region on the other outermost surface in the lateral direction.

15. An optical display device comprising the adhesive film as claimed in claim 1.

Images