Encapsulant composition and light-emitting device

Abstract

The present invention provides: an encapsulant composition comprising at least one multifunctional monomer and at least one monofunctional monomer; and a light-emitting device including an organic film formed by curing the encapsulant composition.

Description

Technical Field

[0001] This disclosure relates to an encapsulant composition, and more specifically, to an encapsulant composition, a cured organic film formed from the encapsulant composition, and a light-emitting device comprising the cured organic film. Background Technology

[0002] Light-emitting devices, especially organic light-emitting devices (OLEDs), are self-emissive devices used in televisions, computers, mobile communication devices, etc. They are widely used in various fields due to their wide viewing angle, excellent contrast, fast response, excellent brightness, low driving voltage, excellent response rate characteristics, and ability to achieve multiple colors.

[0003] Organic light-emitting devices (OLEDs) are adversely affected by oxygen, moisture, and ultraviolet light, leading to a deterioration in their physical properties and lifespan. Therefore, encapsulation devices are introduced to protect OLEDs from these elements. For example, an encapsulation device is considered in which organic layers, which act as barriers against the passage of gases and moisture, and inorganic layers with excellent mechanical properties are alternately stacked. In this case, the inorganic layers can be formed by deposition, and the organic layers can be formed by inkjet printing.

[0004] Meanwhile, in recent years, the reduction in thickness and the improvement in resolution of organic light-emitting devices have introduced various causes of driving failures. Among these, external electrostatic interference with the electrical signal can lead to driving failures. To address this issue, it is important to reduce the dielectric constant of the encapsulation layer.

[0005] However, encapsulant compositions used to form encapsulant layers contain polymers formed by the polymerization of photocurable monomers, but there is a trade-off between the curing properties and dielectric constant of the photocurable monomers. That is, when using photocurable monomers with low dielectric constants, there is a problem of poor curing, while when using photocurable monomers with excellent curing properties, there is a problem of high dielectric constant.

[0006] Therefore, there is a need for an encapsulant composition that can satisfy both curing performance and dielectric constant requirements. Summary of the Invention

[0007] Technical issues Therefore, this disclosure was made in view of the above problems. One aspect of this disclosure is to provide an encapsulant composition and a cured organic film formed by curing the encapsulant composition, which does not interfere with electrical signals even when external static electricity is introduced into the light-emitting device, and can solve the problem of drive failure by being configured with a composition that is optimized to improve both curing performance and dielectric constant.

[0008] Technical solution According to one aspect of this disclosure, the above and other objectives can be achieved by providing an encapsulating composition comprising at least one multifunctional monomer and at least one monofunctional monomer, wherein the multifunctional monomer is represented by the following formula 1: [Formula 1] Where X is hydrogen (H) or methyl; M1 is represented by the following equation 2: [Equation 2] Where R 11 It is a C3-C64 hydrocarbon group, in which R 11 Includes at least one of a linear structure portion or a cyclic structure portion; R 12 It is a hydrogen (H) or C1-C32 hydrocarbon group, wherein the end of the hydrocarbon is substituted with or unsubstituted with an acrylate or methacrylate group; R 13 It is a hydrogen (H) or C1-C32 hydrocarbon group, wherein the end of the hydrocarbon is substituted with an acrylate group or a methacrylate group or is not substituted; M2 is represented by the following equation 3: [Formula 3] Where R 14 It is a C1-C4 straight-chain alkylene group; R 15 It is hydrogen (H) or C1-C32 alkyl; R 16 It is hydrogen (H) or C1-C32 alkyl.

[0009] In one embodiment of this disclosure, R 11 R 12 R 13 R 14 R 15 and R 16 The total number of carbon atoms can be 22 or more.

[0010] In one embodiment of this disclosure, R 12 Can be bonded to R 11 One of the two adjacent carbons contained, R 13 It can bond to another carbon.

[0011] According to one embodiment of this disclosure, R 11 It can contain a ring-shaped structure, R 12 and R 13 It can be bonded to the ring-shaped structure portion.

[0012] According to one embodiment of this disclosure, R 15Can be bonded to R 14 One of the two adjacent carbons contained, R 16 It can bond to another carbon.

[0013] According to one embodiment of this disclosure, R 13 It can include a main chain and side chains, wherein the main chain can be linear and can be bonded to R. 11 One carbon atom, the side chain can be bonded to and bonded to R 11 The main chain has a carbon adjacent to it, and may have ends that are replaced by acrylate groups or methacrylate groups.

[0014] According to one embodiment of this disclosure, the compound according to Formula 1 may include at least one of the compounds represented by Formulas 4 to 15 below: [Formula 4] [Formula 5] [Formula 6] [Formula 7] [Formula 8] [Formula 9] [Formula 10] [Equation 11] [Equation 12] [Equation 13] [Formula 14] [Formula 15] In one embodiment of this disclosure, the monofunctional monomer can be represented by the following formula 16: [Formula 16] Where X can be hydrogen (H) or methyl, R 31 It is a C1-C64 hydrocarbon group, R 31 It includes at least one of a linear structure portion or a cyclic structure portion.

[0015] According to one embodiment of this disclosure, R 31 It can be represented by the following equation 17: [Equation 17] In Equation 17, n can be an integer from 1 to 30, and m can be an integer from 1 to 30.

[0016] According to one embodiment of this disclosure, the compound according to formula 16 may include at least one of the compounds represented by formulas 18 to 20 below: [Formula 18] [Formula 19] [Formula 20] According to one embodiment of this disclosure, the weight ratio of the multifunctional monomer to the monofunctional monomer can be 5 to 95:95 to 5.

[0017] An encapsulant composition according to one embodiment of the present disclosure may have a liquid phase dielectric constant of less than 4.20 at 25°C.

[0018] An encapsulant composition according to one embodiment of the present disclosure may have a solid-phase dielectric constant of less than 2.90 after curing.

[0019] An encapsulant composition according to one embodiment of the present disclosure may have a viscosity of 1 cPs to 50 cPs at 25°C.

[0020] According to another embodiment of the present disclosure, a light-emitting device is provided, wherein at least one surface comprises an organic film formed by curing the above-described encapsulant composition.

[0021] Beneficial effects The encapsulant composition according to the embodiments of this disclosure can exhibit a low dielectric constant, thus solving the problem of external electrostatic interference signals introduced into the substrate and causing drive failure when achieving high-resolution thin films.

[0022] Furthermore, the encapsulant composition according to the embodiments of this disclosure can exhibit a low dielectric constant, thereby preventing capacitive interference.

[0023] Furthermore, the encapsulant composition according to embodiments of this disclosure has a low dielectric constant but ensures curing performance, which is generally known to be a property incompatible with dielectric constant, providing improved storage stability and jetting spreadability, suitable for inkjet processes, and improving lifetime and reliability stability related to the physical properties of the light-emitting device.

[0024] Furthermore, the encapsulant composition according to the embodiments of this disclosure has the effect of being used as an encapsulant without additionally forming an encapsulation film. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view showing a portion of a display device including a light-emitting device according to another embodiment of this disclosure. Detailed Implementation

[0026] In the following description, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, the following embodiments are provided illustratively only for the purpose of clear understanding of the present disclosure and do not limit the scope of the disclosure.

[0027] The shapes, dimensions, ratios, angles, and numbers disclosed in the accompanying drawings used to describe embodiments of this disclosure are merely examples, and this disclosure is not limited to the details shown. Throughout this specification, the same reference numerals refer to the same elements. In the following description, detailed descriptions of relevant known functions or configurations will be omitted where such omissions would unnecessarily obscure the focus of this disclosure.

[0028] Where terms such as “comprising,” “having,” or “including” are used in this specification, another part may also exist, unless “only” is also used. Unless otherwise stated, singular terms may include plural meanings. Furthermore, when interpreting an element, even if not explicitly described, the element will be interpreted as including a range of tolerances.

[0029] When describing positional relationships, for example, when using "above," "over," "below," or "beside," situations where there is no contact between them may also be included unless "immediately following" or "directly" is used.

[0030] Spatial relative terms such as “below,” “under,” “lower,” “above,” and “upper” may be used in this specification to describe the relationship between a device or element and another device or element, as illustrated in the accompanying drawings. It should be understood that, in addition to the orientations depicted in the drawings, spatial relative terms are also intended to cover different orientations of the device during use or operation of the device. For example, if the device in one of the drawings is inverted, an element described as “below” or “under” other elements would be positioned “above” other elements. Therefore, the exemplary terms “below” or “under” may encompass the meanings of both “below” and “upper.” Similarly, the exemplary terms “above” or “upper” may encompass the meanings of both “above” and “below.”

[0031] When describing temporal relationships, for example, when using "after," "following," "next," or "before" to describe temporal sequence, non-continuous relationships can also be included unless "immediately" or "directly" is used.

[0032] It should be understood that although the terms "first," "second," etc., may be used in this specification to describe various elements, these elements are not limited by these terms. These terms are only used to distinguish one element from another. Therefore, within the technical concept of this disclosure, a first element may be referred to as a second element.

[0033] It should be understood that the term "at least one" includes all combinations relating to one or more items. For example, "at least one of the first element, the second element, and the third element" can include two or more elements selected from the first element, the second element, and the third element, as well as all combinations of each of the first element, the second element, and the third element.

[0034] Features of the various embodiments of this disclosure can be integrated or combined with each other in part or in whole, and can interoperate and be technology-driven with each other in various ways. Embodiments of this disclosure can be implemented independently of each other, or can be implemented together in an interconnected manner.

[0035] Before the detailed description of this disclosure that follows, it should be understood that the terminology used in this specification is for describing particular embodiments only and is not limited to the appended claims. Unless otherwise stated, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art.

[0036] Furthermore, based on the principle that inventors can appropriately define the concepts of terms in order to best describe this disclosure, the terms or words used in this specification and the appended claims are intended to be interpreted as having meanings and concepts consistent with the technical concept of this disclosure described in this specification, and are not limited to common or dictionary meanings.

[0037] In one embodiment of this disclosure, the disclosure relates to an encapsulant composition capable of being printed and photocured on a substrate. Specifically, the encapsulant composition is an organic composition capable of forming an organic layer of encapsulant.

[0038] As used in this specification, the term "printing" may refer to any of the various types of coatings, including inkjet printing.

[0039] An encapsulant containing a cured product formed from an organic composition can be applied to an organic light-emitting device to reduce or prevent damage to the organic layer of the device due to physical impact or foreign substances such as oxygen or moisture.

[0040] Furthermore, the encapsulant composition according to this disclosure is configured to perform the function of protecting the light-emitting device, which is an inherent function of the encapsulant, and effectively prevents the introduction of static electricity that interferes with electrical signals.

[0041] In this disclosure, the encapsulant composition may be a solvent-free photocurable composition. That is, the composition used to form the cured organic film for the encapsulant, described later, may be a solvent-free composition containing a photocurable component.

[0042] As used in this specification, the term "solvent-free composition" means a composition that does not contain solvents such as organic solvents or aqueous solvents.

[0043] As used in this specification, the term "photocurable composition" refers to a composition that can be cured by free radical polymerization using light irradiation. Photocuring can be carried out, for example, by irradiation with electromagnetic waves such as microwaves, infrared rays, ultraviolet rays, and gamma rays, or particle beams such as alpha particle beams or electron beams including proton beams and neutron beams.

[0044] There are no particular restrictions on the specific photocuring conditions. However, for example, when using ultraviolet light for photocuring, the wavelength can be in the range of 290nm to 400nm, which is the near-ultraviolet region, and the light intensity during the total time of ultraviolet irradiation can be 400mW / cm². 2 Below, more specifically, at 100mW / cm 2 Up to 400mW / cm 2 Within this range, the light intensity can reach 300 mJ / cm. 2 Up to 2,500 mJ / cm 2 More specifically, 500mJ / cm 2 Up to 1,500 mJ / cm 2 Within the range.

[0045] Compared to solvent-based compositions, solvent-free compositions do not require a solvent drying process, thus improving process efficiency and overcoming disadvantages such as the formation of bubbles due to solvents and the degradation of encapsulant functionality.

[0046] Furthermore, solvent-free compositions can reduce the water content in encapsulant compositions, thus offering the advantage of being suitable for organic light-emitting devices that are susceptible to moisture.

[0047] Furthermore, the composition can be applied to a substrate by inkjet printing. Inkjet printing is generally advantageous for large-scale production, etc., because it uses multiple heads comprising multiple nozzles connected to each other. The composition is configured to meet the viscosity and surface energy (surface tension) requirements set forth below for suitability for inkjet printing.

[0048] To enable photocurability of the composition, the composition may contain a compound having photocurable functional groups. Specifically, the composition may be provided as a composition that imparts a reduced dielectric constant by containing a multifunctional monomer.

[0049] Unless otherwise stated, the term "dielectric constant" as used in this specification refers to the liquid phase dielectric constant. Specific measurement methods are disclosed in the experimental examples described later.

[0050] To reduce the dielectric constant, weakly polar monomers should be used. Monomers with low dielectric constants (despite their weak polarity) typically possess only one functional group that generates a free radical during photocuring. Therefore, a trade-off exists between dielectric constant and curing performance; for example, a cured film may not form even after photocuring.

[0051] Therefore, by combining monomers that can improve insufficient curing performance, such as monomers with high dielectric constants but also with sufficient functional groups to generate free radicals during photocuring and to form the desired cured film during photocuring, an encapsulant composition is provided that exhibits storage stability and sufficient spray spreadability compared to the prior art, while significantly reducing the dielectric constant by more than 20%.

[0052] According to one embodiment of this disclosure, an encapsulant composition can be prepared using at least one multifunctional monomer and at least one monofunctional monomer.

[0053] In one aspect, this disclosure relates to an encapsulant composition comprising at least one multifunctional monomer and at least one monofunctional monomer, wherein the multifunctional monomer is represented by the following formula 1: [Formula 1] Where X is hydrogen (H) or methyl.

[0054] In Formula 1, the multifunctional monomer may have acrylate groups or (meth)acrylate groups as photocurable functional groups.

[0055] In one implementation, M1 is represented by Equation 2 below.

[0056] [Equation 2] In Equation 2, * represents the bond position. In Equation 2, R 11 It can be a C3-C64 hydrocarbon group, R 11 It may include at least one of a linear structural portion or a cyclic structural portion. More specifically, R 11 It can have 8 to 32 carbon atoms.

[0057] In this disclosure, the linear structure portion refers to at least a portion of the entire structure comprising a linear structure, and the ring structure portion refers to at least a portion of the entire structure comprising a ring structure.

[0058] Therefore, when a linear structure is included, the entire structure can be a linear structure, or a portion of the structure can be a linear structure. Similarly, when a ring-shaped structure is included, the entire structure can be a ring-shaped structure, or a portion of the structure can be a ring-shaped structure. Here, the ring-shaped structure can contain a single ring or multiple rings.

[0059] R 12 It is a hydrogen (H) or C1-C32 hydrocarbon group, wherein the end of the hydrocarbon is substituted with or unsubstituted with an acrylate or methacrylate group. More specifically, R 12 It can be a C1-C15 straight-chain alkyl group.

[0060] R 13 It is a hydrogen (H) or C1-C32 hydrocarbon group, wherein the end of the hydrocarbon is substituted with or unsubstituted with an acrylate or methacrylate group. More specifically, R 13 It can be a C5-C27 straight-chain alkyl group.

[0061] In one implementation, M2 is represented by the following formula 3.

[0062] [Formula 3] In Equation 3, * represents the bond position. In Equation 3, R 14 It can be a C1-C4 straight-chain alkylene group.

[0063] R 15 It can be hydrogen (H) or C1-C32 alkyl. More specifically, R 15 It can be a C1-C15 straight-chain alkyl group.

[0064] R16 It is hydrogen (H) or a C1-C32 alkyl group. More specifically, R 16 It can be a C5-C15 straight-chain alkyl group.

[0065] In one embodiment of this disclosure, R 11 R 12 R 13 R 14 R 15 and R 16 The total number of carbon atoms can be 22 or more.

[0066] According to one embodiment of this disclosure, for example, R 11 and R 14 The total number of carbon atoms can be 22 or more.

[0067] According to one embodiment of this disclosure, R 11 It may include a ring-shaped structural portion, and the ring-shaped structural portion may include at least one alicyclic ring.

[0068] According to one embodiment of this disclosure, R 11 It may contain a cyclic structural portion, and the cyclic structural portion may contain at least one aromatic ring.

[0069] Typically, multifunctional monomers with simple linear structures containing more than 14 carbon atoms are solids at room temperature. Therefore, solvents may be required when preparing encapsulant compositions using such multifunctional monomers.

[0070] Meanwhile, although multifunctional monomers with simple linear structures and containing more than 14 carbon atoms are liquids at room temperature, encapsulant compositions prepared using such multifunctional monomers may not have sufficient storage stability.

[0071] On the other hand, although a multifunctional monomer according to one embodiment of this disclosure contains linear R 11 Therefore, it has a straight main chain structure, but unlike R... 11 bonded R 12 and R 13 At least one of them can be a C1-C32 hydrocarbon group. Furthermore, with R... 11 R together constitutes the main chain 14 bonded R 15 Or R 16 At least one of them can be a C1-C32 alkyl group.

[0072] In this case, the multifunctional monomer has a chain structure with branches included in the main chain of the linear structure, rather than a simple linear structure, and is therefore liquid at room temperature. Thus, when using multifunctional monomers with chain structures to prepare encapsulant compositions, solvents can be omitted, and the preparation of the encapsulant compositions can be straightforward.

[0073] According to one embodiment of this disclosure, the multifunctional monomer may contain R 11 It has the following configuration: where R 12 Bond to R 11 One carbon, R 13 Bond to R 12 bonded R 11 A carbon adjacent to another carbon.

[0074] More specifically, R 12 R can be bonded to multifunctional monomers 11 One of the two adjacent carbons contained, R 13 It can bond to another carbon.

[0075] As used in this specification, the term "two adjacent carbon atoms" refers to carbon atoms bonded to each other.

[0076] According to one embodiment of this disclosure, when R 12 R bonded to multifunctional monomers 11 It contains one of two adjacent carbons and R 13 When bonded to another carbon atom, the multifunctional monomer contains a large number of carbon atoms. Therefore, encapsulant compositions prepared using such multifunctional monomers can have a low dielectric constant and can improve the solution stability of the encapsulant composition.

[0077] According to one embodiment of this disclosure, R 11 It can contain a ring-shaped structure, R 12 and R 13 Can be bonded to R 11 The ring-shaped structure portion included therein.

[0078] According to one embodiment of this disclosure, when the R of a multifunctional monomer... 11 When the ring-shaped structure portion is included, the encapsulant composition prepared using it can minimize the increase in dielectric constant and improve the film strength of the organic cured film for encapsulant formed by curing the encapsulant composition.

[0079] According to one embodiment of this disclosure, when R 12 and R 13 R bonded to multifunctional monomers 11When a ring-shaped structural portion is included, encapsulant compositions prepared using polyfunctional monomers containing such a component can exhibit improved solution stability.

[0080] According to one embodiment of this disclosure, the multifunctional monomer may contain R 14 It has the following configuration: where R 15 Bond to R 14 One carbon, R 16 Bond to R 15 bonded R 14 A carbon adjacent to another carbon.

[0081] More specifically, R 15 R can be bonded to multifunctional monomers 14 One of the two adjacent carbons contained, R 16 It can bond to another carbon.

[0082] According to one embodiment of this disclosure, when R 15 R bonded to multifunctional monomers 14 It contains one of two adjacent carbons and R 16 When bonded to another carbon atom, the multifunctional monomer contains a large number of carbon atoms. Therefore, encapsulant compositions prepared using such multifunctional monomers can have a low dielectric constant and can improve the solution stability of the encapsulant composition.

[0083] According to one embodiment of this disclosure, R 13 It can include a main chain and side chains, wherein the main chain can be linear and can be bonded to R. 11 One carbon atom, the side chain can be bonded to and bonded to R 11 The main chain has a carbon adjacent to it, and may have ends that are replaced by acrylate groups or methacrylate groups.

[0084] According to one embodiment of this disclosure, the multifunctional monomer can have two or more photocurable functional groups. When using a multifunctional monomer, high curing speed can be ensured, curing time can be shortened, and the advantages of ensuring the required performance of the cured organic film used as an encapsulant can be obtained.

[0085] According to one embodiment of this disclosure, the compound according to Formula 1 may include at least one of the compounds represented by Formulas 4 to 15 below: [Formula 4] [Formula 5] [Formula 6] [Formula 7] [Formula 8] [Formula 9] [Formula 10] [Equation 11] [Equation 12] [Equation 13] [Formula 14] [Formula 15] According to Formula 1, a multifunctional monomer may have at least two acrylate groups or (meth)acrylate groups as photocurable functional groups.

[0086] According to one embodiment of this disclosure, when a multifunctional monomer has the structure of Formula 1, it can have a large volumetric structure. A multifunctional monomer with a large volumetric structure can reduce the dielectric constant of the encapsulant composition.

[0087] According to one embodiment of this disclosure, two or more multifunctional monomers can be used to appropriately control the dielectric constant of the encapsulant composition.

[0088] According to one embodiment of this disclosure, when a multifunctional monomer is used together with a monofunctional monomer in an encapsulant composition, an encapsulant composition with excellent curing properties can be provided. For example, a multifunctional monomer having a structure of Formula 13 and a monofunctional monomer having a structure of Formula 18 below can be used together.

[0089] When a multifunctional monomer contains the above-mentioned structure, the trade-off between curing and dielectric constant can be resolved. Compared with the prior art, the dielectric constant measured in the composition can be reduced by more than 20%, and excellent spray spreadability and solid-phase transmittance can be provided.

[0090] According to one embodiment of this disclosure, the multifunctional monomer can be liquid at room temperature. When the multifunctional monomer is liquid at room temperature, the encapsulant composition exhibits good storage stability.

[0091] In one embodiment of this disclosure, the monofunctional monomer can be represented by the following formula 16: [Formula 16] Where X can be hydrogen (H) or methyl, R 31 It can be a C1-C64 hydrocarbon group and includes at least one of a straight-chain structural portion or a cyclic structural portion.

[0092] According to Formula 16, a monofunctional monomer may have an acrylate group or a (meth)acrylate group as a photocurable functional group.

[0093] According to one embodiment of this disclosure, R 31 It can be represented by Equation 17 below.

[0094] [Equation 17] In Equation 17, n can be an integer from 1 to 30, and m can be an integer from 1 to 30. More specifically, in Equation 17, n can be an integer from 2 to 12, and m can be an integer from 4 to 16.

[0095] According to one embodiment of this disclosure, R 31 It may include a ring-shaped structural portion. The ring-shaped structural portion may be C3 to C20 and may include at least one alicyclic ring.

[0096] According to one embodiment of this disclosure, R 31 It may include a cyclic structural portion. The cyclic structural portion may be C5 to C18 and may include at least one aromatic ring.

[0097] According to one embodiment of this disclosure, the compound according to formula 16 may include at least one of the compounds represented by formulas 18 to 20 below.

[0098] [Formula 18] [Formula 19] [Formula 20] According to one embodiment of this disclosure, the weight ratio of the multifunctional monomer to the monofunctional monomer can be 5 to 95:95 to 5. More specifically, the weight ratio of the multifunctional monomer to the monofunctional monomer can be 20 to 80:80 to 20, or 40 to 60:60 to 40.

[0099] When the weight ratio of multifunctional monomers to monofunctional monomers is 5 to 95:95 to 5, the dielectric constant of the encapsulant composition can be reduced to a predetermined level, and excellent storage stability and spray spreadability can be obtained. Furthermore, even when external static electricity is supplied through thin films and high-resolution light-emitting devices, degradation of touch performance can be avoided, and a viscosity range of 1 cPs to 50 cPs can be achieved, making it suitable for use as an encapsulant composition.

[0100] According to one embodiment of this disclosure, the encapsulant composition may further comprise an initiator. The initiator can absorb light energy from the outside and provide free radicals for photocuring the monomer compound to the acrylic end groups of each monomer.

[0101] The initiator can be, for example, a material comprising a main chain containing heteroatoms in the molecule and providing free radicals, and at least one aryl end group connected to the main chain via a carbonyl linker.

[0102] As a specific example, the initiator may have a main chain structure represented by any one of Formulas 21 and 22 below, but this disclosure is not limited thereto, and any material that can generally be used as a photocuring initiator is useful.

[0103] [Equation 21] [Equation 22] In addition, initiators can be materials with absorption wavelengths below 500 nm, especially in the range of 380 nm to 410 nm, to improve the photocuring effect.

[0104] Specific examples of initiators include hydroxy ketones such as 1-hydroxycyclohexylphenyl ketone (Irgacure 184), amino ketones such as 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholino)phenyl]-1-butanone (Irgacure 369) and α-aminoacetophenone (Irgacure 907), benzyl dimethyl ketals such as benzyl dimethyl ketal (Irgacure-651), diazygosyl phosphines such as phenylbis(2,4,6)-trimethylbenzoyl (Irgacure 819), and monoacyl phosphines such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO).

[0105] In addition, the encapsulant composition may include one or more additives selected from heat stabilizers, UV stabilizers and antioxidants, and the additives may be selected from a variety of other types of additives.

[0106] Furthermore, according to one embodiment of this disclosure, based on a total of 100 parts by weight of monomeric compound, the initiator may be present in an amount of 10 parts by weight or less, more specifically from 0.1 to 10 parts by weight. When light energy is incident on the encapsulant composition, it is preferable that the initiator content is within the range defined above, so as to provide free radicals suitable for forming a coating to the acrylic end groups of each of the polyfunctional and monofunctional monomers constituting the encapsulant composition.

[0107] In this case, light energy can, for example, come from an intensity of 400 mW / cm². 2 The following, especially 100mW / cm 2 Up to 400mW / cm 2 More importantly, 200mW / cm 2 Up to 400mW / cm 2 The supply of laser or plasma sources, but not limited to these.

[0108] According to one embodiment of this disclosure, the encapsulant composition may further include additives, such as surfactants, adhesive aids for improving adhesion to the substrate, stabilizers, adhesion promoters, curing promoters, thermal polymerization inhibitors, dispersants, plasticizers, fillers, defoamers, etc., to a extent that does not adversely affect the encapsulant composition.

[0109] Based on the total weight of the encapsulant composition, the additive can be used in amounts from 0.001% to 10% by weight. In this case, when the content of the additive does not fall within the above range, the permeability, heat resistance, adhesion to the inorganic barrier layer, and spray stability of the cured film may be poor.

[0110] In this context, surfactants can improve applicability, defoaming properties, leveling properties, etc., and examples include fluorinated surfactants such as BM-1000, BM-1100, Megapack F142D, Megapack F172, Megapack F173, Megapack F183, Fluorad FC-135, Fluorad FC-170C, Fluorad FC-430, Fluorad FC-431, Saffron S-112, Saffron S-113, Saffron S-131, Saffron S-141, Saffron S-145, SH-28PA, SH-190, SH-193, SZ-6032, and SF-8428. In addition, adhesives are, for example, silane coupling agents with reactive substituents, such as carboxyl, methacryloyl, isocyanate, or epoxy groups. Specific examples include trimethoxysilylbenzoic acid, γ-methacryloyloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc.

[0111] According to one embodiment of this disclosure, the composition may not contain silicon-derived units. When the composition contains silicon-derived units, siloxane-based gas release may occur at high temperatures, leading to damage to the light-emitting device.

[0112] According to one embodiment of this disclosure, the composition may have a moisture content of less than 20 ppm before curing. Conventional light-emitting devices are susceptible to moisture. Therefore, if necessary, the moisture content before curing can be adjusted to less than 20 ppm by a dehumidification process.

[0113] Regarding inkjet processes, the preferred encapsulant composition has a viscosity suitable for inkjet processes, such as a viscosity of 1 cPs to 50 cPs measured using a Brookfield viscometer at 25°C.

[0114] When the viscosity of the encapsulant composition at room temperature is between 1 cPs and 50 cPs, both printability and curing performance can be improved. For reference, when the viscosity is too high, it is difficult to eject the composition from the inkjet nozzle, and when the viscosity is too low, it is difficult to form a coating of appropriate thickness due to increased fluidity.

[0115] According to one embodiment of this disclosure, the surface tension of the encapsulant composition is measured to measure the surface energy of the encapsulant composition.

[0116] According to one embodiment of this disclosure, the encapsulant composition may have a surface energy (surface tension) in the range of 20 mN / m to 50 mN / m to facilitate ejection from the inkjet head. The above range is applicable to the smooth ejection of ink from an inkjet device. For reference, when the surface energy (surface tension) of the ink is high, ink droplets may scatter, while when the surface energy (surface tension) is low, the spreadability or dispersibility of the solution may increase upon collision with the substrate.

[0117] Surface energy (surface tension) can be measured at 25°C using any of the known methods, such as the ring method.

[0118] According to one embodiment of this disclosure, the encapsulant composition can have a liquid phase dielectric constant of 4.20 or less at 25°C. More specifically, the encapsulant composition can have a liquid phase dielectric constant of 3.20 to 4.00 at 25°C. Within the above range, even if external static electricity is introduced into the coating, the encapsulant composition with a liquid phase dielectric constant of 4.20 or less can prevent driving failures in the light-emitting device and can effectively protect the coating from oxygen, moisture, and ultraviolet radiation without the need for additional encapsulant.

[0119] Compositions produced in conventional batches have liquid phase dielectric constants ranging from about 4.60 to below 6.20, thus exhibiting disadvantages such as the generation of parasitic capacitances between electrodes or insufficient prevention of capacitive interference. However, encapsulant compositions with the above configuration can have dielectric constants below 4.20, more specifically from 3.20 to 4.00. There is no particular limitation on the lower limit of the dielectric constant, as a lower dielectric constant is beneficial for preventing capacitive interference.

[0120] According to one embodiment of this disclosure, the liquid phase dielectric constant of an encapsulant composition can be measured using a dielectric constant meter model 871 under conditions such as 25°C and 10 kHz frequency.

[0121] The encapsulant composition according to one embodiment of the present disclosure has a curing performance of more than 95% and is cured under N2 atmosphere, at a wavelength of 395 nm and at 1,000 mJ, thus making it suitable for forming an organic encapsulation layer for a light-emitting device.

[0122] When the encapsulant composition according to one embodiment of the present disclosure has optical properties (transmittance) of more than 95% as measured by a UV-Vis spectrometer, the luminescent characteristics and physical properties of the light-emitting device can be improved when it is used as an organic encapsulant layer of the light-emitting device.

[0123] According to one embodiment of this disclosure, a method for photopolymerizing a compound containing an olefinic unsaturated double bond is provided, comprising using an intensity of 400 mW / cm². 2 The following laser or plasma source is irradiated onto the encapsulant composition, wherein the surface hardness is increased by the action of free radicals generated by the light irradiation.

[0124] The solid dielectric constant of the cured organic film obtained by curing the encapsulant composition according to one embodiment of the present disclosure can be 2.90 or less. When the encapsulant composition with a solid dielectric constant of 2.90 or less is applied to an organic light-emitting device, the coating can be protected from the effects of external static electricity, thereby preventing drive failure of the light-emitting device.

[0125] The solid-phase dielectric constant of an encapsulant composition according to one embodiment of the present disclosure can be measured after the encapsulant composition has been cured into an organic film, for example, using a precision impedance analyzer at 25°C and a frequency of 100 kHz.

[0126] According to one embodiment of this disclosure, the encapsulant composition can be used in the wavelength range of 290 nm to 400 nm at a power of 100 mW / cm². 2 Up to 400mW / cm 2 Light intensity and 300mJ / cm 2 Up to 2,500 mJ / cm 2 UV curing under conditions of light intensity.

[0127] According to one embodiment of this disclosure, the encapsulant composition exists in liquid form at room temperature, thus exhibiting excellent storage stability.

[0128] According to one embodiment of the present disclosure, the encapsulant composition can be applied as a thin film onto the organic film 592 of the encapsulant 590.

[0129] On the other hand, this disclosure relates to a light-emitting device 570 having an organic film 592 formed by curing the above-described encapsulant composition.

[0130] Figure 1 This is a cross-sectional view showing a portion of a display device 100 including a light-emitting device 570 according to another embodiment of the present disclosure.

[0131] Reference Figure 1 According to another embodiment of the present disclosure, the display device 100 includes a substrate 510, a thin-film transistor (TFT) on the substrate 510, and an organic light-emitting device 570 connected to the TFT. The organic light-emitting device 570 includes a first electrode 571, an organic light-emitting layer 572 on the first electrode 571, and a second electrode 573 on the organic light-emitting layer 572. Figure 1 The display device 100 shown is an organic light-emitting display device, which includes a light-emitting device 570 according to another embodiment of the present disclosure.

[0132] The substrate 510 can be formed of glass or plastic. Specifically, the substrate 510 can be formed of plastic such as polyimide resin or polyimide film. Although not shown, a buffer layer can be disposed on the substrate 510.

[0133] A thin-film transistor (TFT) is disposed on a substrate 510. The TFT includes a semiconductor layer 520, a gate electrode 530 that is insulated from and at least partially overlaps with the semiconductor layer 520, a source electrode 541 connected to the semiconductor layer 520, and a drain electrode 542 that is spaced apart from the source electrode 541 and connected to the semiconductor layer 520.

[0134] Reference Figure 1 A gate insulating layer 535 is disposed between the gate electrode 530 and the semiconductor layer 520. An interlayer insulating layer 551 may be disposed on the gate electrode 530, and a source electrode 541 and a drain electrode 542 may be disposed on the interlayer insulating layer 551.

[0135] A planarization layer 552 is disposed on the thin-film transistor TFT to planarize the top of the thin-film transistor TFT.

[0136] The first electrode 571 is disposed on the planarization layer 552. The first electrode 571 is connected to the thin-film transistor (TFT) through a contact hole disposed in the planarization layer 552.

[0137] A dam layer 580 is disposed on a planarization layer 552 in a portion of the first electrode 571 to define a pixel region or a light-emitting region. For example, the dam layer 580 is disposed in a matrix at the boundaries between multiple pixels to define corresponding pixel regions.

[0138] An organic light-emitting layer 572 is disposed on the first electrode 571. The organic light-emitting layer 572 may also be disposed on the embankment layer 580. The organic light-emitting layer 572 may include a single light-emitting layer, or two or more light-emitting layers stacked in the vertical direction. Light of any color among red, green, and blue can be emitted from the organic light-emitting layer 572, and white light can also be emitted from it.

[0139] The second electrode 573 is disposed on the organic light-emitting layer 572.

[0140] The first electrode 571, the organic light-emitting layer 572, and the second electrode 573 can be stacked to form an organic light-emitting device 570.

[0141] Although not shown, each pixel may include a color filter for filtering the white light emitted from the organic light-emitting layer 572 based on a specific wavelength when the organic light-emitting layer 572 emits white light. The color filter is formed in the optical path.

[0142] Encapsulant 590 can be disposed on the second electrode 573. Encapsulant 590 can be formed as a multilayer thin film. Encapsulant 590 formed as a multilayer thin film is also referred to as a "thin film encapsulation layer". (See reference...) Figure 1The encapsulant 590 may include at least one organic layer 592 and at least one inorganic layer 593, and the at least one organic layer 592 and at least one inorganic layer 593 may be alternately arranged.

[0143] The encapsulant 590 covers the display area of ​​the display device 100 and can extend outside the display area. The encapsulant 590 may include a first inorganic film 591, an organic film 592, and a second inorganic film 593.

[0144] A first inorganic film 591 covers the second electrode 573. The first inorganic film 591 may include at least one of ceramic, metal oxide, metal nitride, metal carbide, metal oxynitride, silicon oxide, silicon nitride, or silicon oxynitride.

[0145] An organic film 592 is disposed on a first inorganic film 591. The upper surface of the organic film 592 may be a flat surface. Specifically, the organic film 592 may have an upper surface corresponding to a substantially flat display area. The organic film 592 may comprise at least one material selected from acrylic acid, methacrylic acid, polyester, polyethylene, polypropylene, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polyethylene sulfonate, polyoxymethylene, polyarylate, and hexamethyldisiloxane.

[0146] According to another embodiment of this disclosure, the organic film 592 can be formed using an encapsulant composition. More specifically, the organic film 592 can be formed by polymerization and curing of the encapsulant composition.

[0147] The second inorganic membrane 593 covers the organic membrane 592. The second inorganic membrane 593 may include at least one of ceramics, metal oxides, metal nitrides, metal carbides, metal oxynitrides, silicon oxides, silicon nitrides, or silicon oxynitrides.

[0148] According to another embodiment of this disclosure, since the encapsulant 590 has a multilayer structure including a first inorganic film 591, an organic film 592, and a second inorganic film 593, even if cracks form in the encapsulant 590, the cracks will not propagate between the first inorganic film 591 and the organic film 592 or between the organic film 592 and the second inorganic film 593. This prevents or minimizes the formation of pathways for moisture or oxygen to penetrate into the light-emitting device 570 from the outside.

[0149] Reference Figure 1 The touch panel 110 can be placed on the encapsulant 590. In addition, protective films, windows, etc. can be set on the encapsulant 590.

[0150] The encapsulant composition according to one embodiment of the present disclosure can be applied to printing inks and various resists.

[0151] According to ASTM D1003, the transmittance of the cured film formed by curing an encapsulant composition according to one embodiment was measured using a UV-Vis spectrometer and found to be above 95%, with a significantly improved surface hardness compared to existing technologies.

[0152] Non-limiting examples of substrates used for curing films include substrates for electronic components, substrates on which predetermined wiring patterns are formed, etc. Examples of substrates include glass or plastic substrates coated or uncoated with silicon, silicon nitride, silicon oxide, titanium, tantalum, palladium, titanium tungsten, copper, chromium, aluminum, AlNd, ITO, IGZO, etc.

[0153] The present disclosure will be described in more detail below with reference to embodiments and comparative examples. However, the following embodiments and comparative examples should not be construed as limiting the scope of the present disclosure.

[0154] <Preparation of Encapsulant Composition> As shown in Table 2 below, compositions of examples and comparative examples with different monomer compositions and contents were prepared using the photocurable monomers shown in Table 1 below. 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide (TPO) was used as the polymerization initiator. The polymerization initiator was used in an amount of 3 parts by weight based on 100 parts by weight of total monomers.

[0155] [Table 1] Photocurable monomer A: Formula 4 Photocurable monomer B: Formula 15 Photocurable monomer C: Formula 13 Photocurable monomer D: Formula 14 Photocurable monomer E: Formula 8 Photocurable monomer F: Formula 10 Photocurable monomer G: Formula 18 Photocurable monomer H: Formula 19 Photocurable monomer I: 1,6-hexanediol dimethacrylate (HDDMA) Photocurable monomer J: Bisphenol A (ethylene oxide) 10 Dimethacrylate (BPA(EO)) 10 DMA) [Table 2] In Table 2, % by weight refers to the weight of each monomer relative to the total monomers.

[0156] Methods for measuring physical properties 1. Physical properties before curing The physical properties of the encapsulant compositions prepared according to Examples 1 to 13 and Comparative Example 1 before curing were measured as follows, according to Table 2.

[0157] (1) Liquid dielectric constant The liquid phase dielectric constant of the encapsulant compositions according to Examples 1 to 13 and Comparative Example 1 was measured at 10 kHz and 25 °C using a dielectric constant meter, model 871.

[0158] (2) Viscosity The viscosity of the encapsulant compositions according to Examples 1 to 13 and Comparative Example 1 was measured as follows.

[0159] Measurement standard: Measured according to the method specified in ASTM D 2196. Measuring device: Brookfield DV2T model Measurement conditions: Cone-plate mode Temperature measured: 25℃ Measurement method: Load 0.5 ml of encapsulant composition and measure at 50% torque.

[0160] (3) Surface energy (surface tension) The surface energy (surface tension) of the encapsulant compositions according to Examples 1 to 13 and Comparative Example 1 were measured as follows.

[0161] Measurement standard: Measured according to the method specified in ISO 304. Measuring device: K9 tension meter from KRUSS Measurement mode: O-ring, maximum mode Temperature measured: 25℃ Measurement method: 20g of polymerizable composition was applied to an O-ring and the surface energy (surface tension) was measured using a KRUSS K9 tensiometer in maximum measurement mode.

[0162] 2. Performance after curing The solid dielectric constants of the encapsulant compositions prepared according to Examples 1 to 13 and Comparative Example 1 after curing were measured as follows, based on Table 2 above.

[0163] 1) Sample preparation Solid dielectric constant samples were prepared by spin-coating each of the encapsulant compositions according to Examples 1 to 13 and Comparative Example 1, prepared according to Tables 1 and 2, onto a Cr glass substrate (Cr thickness of 1,600 Å), and then curing (thickness of 8.0 μm, exposure dose of 1,000 mJ / cm²). 2 Then, Al (1,000 Å thickness, 3.0 × 3.0 mm size) was deposited on the organic curing film. 2).

[0164] 2) Measurement method The solid dielectric constant of the encapsulant composition was measured using a precision impedance analyzer at 25°C and 100 kHz.

[0165] <Measurement results of physical properties> Table 3 below shows the physical properties measured according to the evaluation items of the encapsulant composition or cured product.

[0166] [Table 3] As can be seen from the results in Table 3 above, considering the trade-off between curing properties and dielectric constant, the encapsulant compositions of Examples 1 to 13 with appropriately mixed compositions have lower dielectric constants than the encapsulant compositions of Comparative Example 1 with unmixed or improperly mixed compositions or compositions containing monomers with different structures. Specifically, Examples 1 to 13 exhibit solid-phase dielectric constants in the range of 2.27 to 2.82, while Comparative Example 1 exhibits a solid-phase dielectric constant of 4.80.

[0167] Furthermore, it can be seen that, considering the compatibility between curing properties and dielectric constant, the encapsulant compositions according to Examples 1 to 13 with appropriate mixing exhibit a 53% reduction in solid-phase dielectric constant compared to Comparative Example 1.

[0168] The features, structures, effects, etc., illustrated in each of the above embodiments can be combined or modified by those skilled in the art in other embodiments. Therefore, anything relating to such combinations and modifications should be construed as falling within the scope of this disclosure.

[0169] [Explanation of reference numerals in the attached figures] 100: Display device; 110: Touch panel 510: Substrate; 520: Semiconductor layer 530: Gate electrode; 541: Source electrode 542: Drain electrode; 570: Light-emitting device 571: First electrode; 572: Organic light-emitting layer 573: Second electrode; 590: Encapsulant 591: First inorganic membrane 592: Organic membrane 593: Second Inorganic Membrane

Claims

1. An encapsulant composition comprising: At least one multifunctional monomer; and At least one monofunctional monomer, The multifunctional monomer is represented by the following formula 1: [Formula 1] Where X is hydrogen (H) or methyl; M1 is represented by the following equation 2: [Equation 2] Where R 11 It is a C3-C64 hydrocarbon group, R 11 It includes at least one of a linear structure portion or a cyclic structure portion; R 12 It is a hydrogen (H) or C1-C32 hydrocarbon group, wherein the end of the hydrocarbon is substituted with an acrylate group or a methacrylate group or is not substituted; R 13 It is a hydrogen (H) or C1-C32 hydrocarbon group, wherein the end of the hydrocarbon is substituted with an acrylate group or a methacrylate group or is not substituted; M2 is represented by the following equation 3: [Formula 3] Where R 14 It can be a C1-C4 straight-chain alkylene group; R 15 It is hydrogen (H) or a C1-C32 alkyl group; R 16 It is hydrogen (H) or C1-C32 alkyl.

2. The encapsulant composition according to claim 1, wherein, R 11 R 12 R 13 R 14 R 15 and R 16 The total number of carbon atoms is 22 or more.

3. The encapsulant composition according to claim 1, wherein, R 12 Bond to R 11 One of the two adjacent carbons contained, R 13 It bonds to another carbon.

4. The encapsulant composition according to claim 1, wherein, R 11 Including the ring-shaped structure portion, and R 12 and R 13 Bonded to the ring structure portion.

5. The encapsulant composition according to claim 1, wherein, R 15 Bond to R 14 One of the two adjacent carbons contained, R 16 It bonds to another carbon.

6. The encapsulant composition according to claim 1, wherein, R 13 Includes main chain and side chain, The main chain is linear and bonded to R. 11 One carbon, and The sidechain is bonded to and bonded to R 11 The main chain of the carbon is adjacent to a carbon and has an end that is replaced by an acrylate group or a methacrylate group.

7. The encapsulant composition according to claim 1, wherein, The compounds of Formula 1 include at least one of the compounds represented by Formulas 4 to 15 below: [Formula 4] [Formula 5] [Formula 6] [Formula 7] [Formula 8] [Formula 9] [Formula 10] [Equation 11] [Equation 12] [Equation 13] [Formula 14] [Formula 15] 。 8. The encapsulant composition according to claim 1, wherein, The monofunctional monomer is represented by the following formula 16: [Formula 16] Where X is hydrogen (H) or methyl, R 31 It is a C1-C64 hydrocarbon group. R 31 It includes at least one of a linear structure portion or a cyclic structure portion.

9. The encapsulant composition according to claim 8, wherein, R 31 Equation 17 below represents: [Equation 17] Where n is an integer from 1 to 30, and m is an integer from 1 to 30.

10. The encapsulant composition according to claim 8, wherein, The compound of Formula 16 includes at least one of the compounds represented by Formulas 18 to 20 below: [Formula 18] [Formula 19] [Formula 20] 。 11. The encapsulant composition according to claim 1, wherein, The weight ratio of the multifunctional monomer to the monofunctional monomer is 5 to 95:95 to 5.

12. The encapsulant composition according to claim 1, wherein, The encapsulant composition has a liquid phase dielectric constant of less than 4.20 at 25°C.

13. The encapsulant composition according to claim 1, wherein, The encapsulant composition has a solid-state dielectric constant of less than 2.90 after curing.

14. The encapsulant composition according to claim 1, wherein, The encapsulant composition has a viscosity of 1 cPs to 50 cPs at 25°C.

15. A light-emitting device having at least one organic film formed by curing an encapsulant composition according to any one of claims 1 to 14.

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