Encapsulation material using a curable composition and an encapsulation material for an organic light emitting device comprising the same

Abstract

The present application relates to a curable composition for encapsulating material and an encapsulating material for organic light emitting device comprising the same, and more particularly, can provide a curable composition for encapsulating material and an encapsulating material for organic light emitting device comprising the same, which are excellent in adhesion, adhesion reliability, stability over time at room temperature and high temperature, durability and conformability, while being very outstanding in moisture permeation prevention properties.

Description

TECHNICAL FIELD

[0001] The present application relates to a curable composition for encapsulating material and an encapsulating material for an organic light emitting device comprising the same, and more particularly, to a curable composition for encapsulating material and an encapsulating material for an organic light emitting device comprising the same, which are excellent in moisture permeation preventing property, adhesion, adhesion reliability, stability over time at room temperature and high temperature, durability, and conformability. BACKGROUND

[0002] An organic light emitting device (OLED) is a light emitting device in which a light emitting layer disposed between facing electrodes is formed of a thin film of an organic compound, and when an electron injected from one side electrode and a hole injected from the other side electrode recombine in the light emitting layer, electroluminescence occurs in which light is emitted from a fluorescent or phosphorescent organic compound of the light emitting layer.

[0003] Compared to other electronic devices, an organic light emitting device is more susceptible to moisture, and problems such as a significant decrease in light emitting characteristics occur due to oxidation of an electrode or denaturation of an organic compound by moisture, impurities, etc. permeated into the organic light emitting device. Therefore, in order to solve the above problems, a technique of encapsulating an organic light emitting device using a material excellent in moisture permeation preventing property and also excellent in optical characteristics as an encapsulating material composition has been adopted.

[0004] On the other hand, depending on the direction of light emission, an organic light emitting device is classified into a bottom emission type and a top emission type. In the structure of an organic electronic light emitting device of the bottom emission type, there is a disadvantage in that the aperture ratio (area capable of emitting light in a unit pixel) is reduced due to the area occupied by a thin film transistor (TFT) circuit, but a metal cathode can be selected, and there is an advantage in that even if a getter is not transparent, it does not matter.

[0005] In contrast, compared to the structure of the bottom emission type, the structure of the organic light emitting device of the top emission type can achieve high resolution display due to a high aperture ratio, but a transparent cathode is required, and an encapsulating material technique not using a getter that hinders optical characteristics is also required, and thus the materials that can be used are restricted. Therefore, in the organic electronic light emitting device of the top emission type, an encapsulating composition applied through a dam and fill encapsulation process is used as an encapsulating material composition, a method of providing a dam material to the edge portion of the organic electronic light emitting device to form a barrier, and using a fill material to encapsulate the inside thereof is used.

[0006] Recently, as the organic electroluminescent device technology is further advanced and the use thereof is diversified, the encapsulating material for the organic electroluminescent device also needs to be further improved in moisture permeation prevention properties, adhesion, adhesion reliability, stability over time at normal and high temperatures, durability, and lamination.

[0007] In particular, in the case where the moisture permeation prevention properties of the encapsulating material for the organic electroluminescent device need to be significantly high, it is known that the general approach is to increase the content of the moisture absorbent in the encapsulating material composition. However, if the content of the moisture absorbent is too high, cracks and warping from the substrate can occur inside the encapsulating resin due to excessive swelling of the diluent upon absorption of moisture, thereby accelerating the moisture permeation speed, and the moisture permeation prevention properties can be reduced, and thus problems in appearance at the time of lamination can occur. Therefore, there is a need to develop an encapsulating material for the organic electroluminescent device that solves these problems and significantly improves the moisture permeation prevention properties. SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] An object of the present application is to provide a curable composition for an encapsulating material and an encapsulating material for an organic electroluminescent device, which are excellent in moisture absorption resistance, adhesion, adhesion reliability, stability over time at normal and high temperatures, durability, and lamination.

[0010] Further, an object of the present application is to provide a curable composition for an encapsulating material and an encapsulating material for an organic electroluminescent device, which can significantly improve the moisture permeation prevention properties while exhibiting excellent durability and lamination compared to conventional encapsulating materials for organic electroluminescent devices.

[0011] TECHNICAL SOLUTION

[0012] In order to solve the above problems, according to an embodiment of the present application, a curable composition for an encapsulating material can be provided, which comprises: an encapsulating resin comprising two isobutylene resins having different molecular weights; a moisture-resistant petroleum resin; and a first acrylic curing agent, the isobutylene resins are represented by the following formula (1) and comprise a first isobutylene resin having a molecular weight of 5,000 Mw to 50,000 Mw and a second isobutylene resin having a molecular weight of 800 Mw to 4,000 Mw, and the moisture-resistant petroleum resin is a dicyclopentadiene petroleum resin having a softening point of 60°C to 100°C.

[0013] Chemical Formula (1)

[0014]

[0015] In the above formula (1), n is an integer of 1 or more.

[0016] The above dicyclopentadiene petroleum resin can be subjected to hydrogenation treatment.

[0017] The above encapsulating resin can contain 20 to 120 parts by weight of the above moisture-resistant petroleum resin, based on 100 parts by weight of the above encapsulating resin.

[0018] The above encapsulating resin can contain 10 to 300 parts by weight of the above second isobutylene resin, based on 100 parts by weight of the above first isobutylene resin.

[0019] The above first acrylic curing agent is a monofunctional (meth)acrylate curing agent containing dicyclopentadiene (DCPD) and has a glass transition temperature (Tg) of 100 to 200°C. The above encapsulating resin can contain 10 to 100 parts by weight of the above first acrylic curing agent, based on 100 parts by weight of the above encapsulating resin.

[0020] The above encapsulating material curing composition can further contain a second acrylic curing agent. The above second acrylic curing agent is a difunctional (meth)acrylate curing agent containing dicyclopentadiene and has a glass transition temperature of 100 to 200°C. The above encapsulating resin can contain 1 to 5 parts by weight of the above second acrylic curing agent, based on 100 parts by weight of the above encapsulating resin.

[0021] The above encapsulating material curing composition can further contain an inorganic moisture absorbent. The above encapsulating material curing composition can contain 35 to 65% by weight of the above inorganic moisture absorbent, based on 100% by weight of the total solid content of the above encapsulating material curing composition.

[0022] The above encapsulating material curing composition can further contain an inorganic moisture absorbent.

[0023] The initial viscosity (V i ) of the above encapsulating material curing composition can be 150,000 to 250,000 mPa·S.

[0024] The above encapsulating material curing composition can satisfy the following relation expression 1 and relation expression 2.

[0025] Relation expression 1: [(V 25℃ -V i ) / V i ] × 100 < 1%

[0026] Relation expression 2: [(V 40℃ -V i ) / V i ] × 100 < 3%

[0027] In the above relation expression 1 and relation expression 2, V i is the initial viscosity, and V25℃ V is a viscosity after standing for 7 days at a temperature of 25°C 40℃ V is a viscosity after standing for 7 days at a temperature of 40°C.

[0028] According to still another embodiment of the present application, the present application can provide an encapsulating material for an organic light emitting device formed by curing the curable composition for an encapsulating material according to the above-described embodiment of the present application.

[0029] The above-described encapsulating material for an organic light emitting device can satisfy the following relation 3. i ) can be 150 N / cm 2 ~ 400 N / cm 2 .

[0030] The above-described encapsulating material for an organic light emitting device can satisfy the following relation 3.

[0031] Relation 3: [(A f -A i ) / A i ] x 100 ≤ 30%

[0032] In the above-described relation 3, A i is an initial adhesion to glass, and A f is an adhesion after standing for 1000 hours (hr) at a temperature of 85°C.

[0033] The above-described encapsulating material for an organic light emitting device can have a moisture permeation length of less than 1.4 mm / 1000 hours after standing for 1000 hours at a temperature of 85°C.

[0034] According to another embodiment of the present application, an organic light emitting device employing the encapsulating material for an organic light emitting device according to the above-described still another embodiment of the present application can be provided.

[0035] Effects of the Invention

[0036] The moisture permeation prevention properties, adhesion, adhesion reliability, stability over time at room temperature and at high temperature, durability, and conformability of the curable composition for an encapsulating material and the encapsulating material for an organic light emitting device including the same according to the present application can be greatly improved.

[0037] In particular, the curable composition for an encapsulating material and the encapsulating material for an organic light emitting device including the same according to the present application can have excellent durability and conformability while significantly improving moisture permeation prevention properties, as compared to conventional encapsulating materials for an organic light emitting device.

[0038] The specific effects of the present application will be described together with the above-described effects in the following description of specific matters for practicing the present application. DETAILED DESCRIPTION

[0039] The foregoing objects, features, and advantages will be described in detail in the following description with reference to the drawings. A person of ordinary skill in the art to which the present application pertains can easily implement the technical idea of the present application based on the following description.

[0040] In describing the present application, detailed description of the well-known technology related to the present application will be omitted when it is determined that it can unnecessarily obscure the gist of the present application.

[0041] In the present specification, the content which can be easily technically inferred by a person of ordinary skill in the art to which the present application pertains will be omitted.

[0042] In the present specification, "(meth)acrylate" can mean both acrylate and methacrylate.

[0043] In the present specification, "moisture penetration prevention property" is embodied in "moisturability" and / or "moisture-resistance" of a specific component, "moisturability" can be used in the meaning that it embodies the property of a specific component itself to absorb moisture, and "moisture-resistance" other than "moisturability" can be used in the meaning that it embodies the property of a specific component itself to prevent moisture penetration.

[0044] In the present specification, the term "dicyclopentadiene (DCPD) resin" used in association with "moisture-resistant petroleum resin" is a petroleum resin containing a monomer derived from dicyclopentadiene as a main raw material, and the monomer derived from dicyclopentadiene can include one or more of substituted or unsubstituted.

[0045] In the present specification, the term "containing dicyclopentadiene" used in association with "acrylic curing agent" can mean the meaning that a functional group derived from dicyclopentadiene is contained by combining dicyclopentadiene with (meth)acrylate to form a compound.

[0046] In the present specification, "monofunctional (meth)acrylate" can mean the meaning that one (meth)acryloyl group is present in a molecule, and "difunctional (meth)acrylate" can mean the meaning that two (meth)acryloyl groups are present in a molecule.

[0047] In the present specification, "glass transition temperature (Tg)" can be an intrinsic value measured when a specific component is formed into a "homo polymer".

[0048] In the present specification, the "viscosity" can be a value measured at 25°C and 2.5 rpm using an E-type Cone-Plate Type viscometer (Toki-sangyo Co., Ltd., TVE-35H).

[0049] In the present specification, the unit "parts by weight" can mean the weight ratio between the components.

[0050] In the present specification, the singular expression used herein includes the plural expression unless clearly defined otherwise in the context. In the present specification, the terms "comprising", "containing", "having" and the like shall not be construed to mean that all the multiple structural elements listed in the specification are necessarily included, but can be construed to mean that some of the structural elements can be excluded, or additional structural elements can be included.

[0051] Hereinafter, a curable composition for a packaging material according to an embodiment of the present application will be described in detail.

[0052] Curable composition for a packaging material

[0053] Packaging resin

[0054] Conventionally, only a relatively large molecular weight isobutylene resin has been used, in which case, adhesion can be reduced due to insufficient adhesion of the base material, or a viscosity reducing agent, a diluent, a curing agent, or the like can be additionally added due to excessively high viscosity, thus there is a limitation in which the moisture absorption of the packaging material is low. In order to improve the above limitation, the packaging resin of the present application mixes a relatively small molecular weight isobutylene resin in a relatively large molecular weight isobutylene resin.

[0055] The curable composition for a packaging material of the present application can include a packaging resin including two kinds of isobutylene resins having different molecular weights, and a first acrylic curing agent. The above isobutylene resin is represented by the following Chemical Formula (1), and can include a first isobutylene resin having a molecular weight of 5000 Mw to 50000 Mw and a second isobutylene resin having a molecular weight of 800 Mw to 4000 Mw.

[0056] Chemical Formula (1)

[0057]

[0058] In the above Chemical Formula (1), n is an integer of 1 or more.

[0059] If the molecular weight of the above first isobutylene resin is greater than 50000 Mw, the adhesion of the base material can be reduced, and if the molecular weight of the above second isobutylene resin is less than 800 Mw, a problem of reducing moisture resistance can occur.

[0060] In this case, from the viewpoint of achieving sufficient moisture resistance while improving the adhesion of the substrate, preferably, 10 to 300 parts by weight of the second isobutylene resin described above is contained, based on 100 parts by weight of the first isobutylene resin described above, more preferably, 50 to 200 parts by weight of the second isobutylene resin described above is contained, and most preferably, 100 parts by weight of the second isobutylene resin described above is contained.

[0061] Moisture-resistant petroleum resin

[0062] As described above, in order to improve the moisture penetration prevention properties, the encapsulating material curable composition of the present application is characterized by containing a moisture-resistant petroleum resin.

[0063] In the present application, the "moisture-resistant petroleum resin" refers to a petroleum resin that exhibits excellent moisture resistance when used in an encapsulating material curable composition. Specifically, preferably, the moisture-resistant petroleum resin of the present application uses a dicyclopentadiene petroleum resin having a softening point of 60 to 100°C, and if the softening point is less than 60°C, it cannot exist in a solid form at room temperature, and if the softening point is more than 100°C, the adhesion is reduced.

[0064] The dicyclopentadiene petroleum resin described above is a series that is known to be used as a tackifying resin in the past, and is prepared using an aliphatic C5 fraction or an aromatic C9 fraction generated in a naphtha cracking process (NCC process), and is classified into a C5 petroleum resin, a C9 petroleum resin, a dicyclopentadiene (DCPD, separated from the C5 fraction) petroleum resin, or a petroleum resin in a mixed copolymer form thereof, etc., and is known to be used in adhesives for the purpose of improving adhesion.

[0065] However, the present inventors have confirmed through experiments that, as a result of using a petroleum resin, which is one of tackifying resins, in an encapsulating material curable composition, the moisture penetration prevention properties are significantly improved compared to the case where the tackifying resin described above is not used, and the adhesion is maintained at a similar level or even somewhat reduced. Therefore, in the present application, in order to distinguish the tackifying properties thereof, it is referred to as a moisture-resistant petroleum resin.

[0066] Further, in the case where "a dicyclopentadiene petroleum resin having a softening point of 60 to 100°C" is added to an encapsulating material curable composition, compared to the case where another kind of petroleum resin such as a C9 petroleum resin is added, the durability and adhesion required for the encapsulating material can be satisfied, and in particular, the moisture penetration prevention properties can be significantly improved.

[0067] Also, in the case where the dicyclopentadiene petroleum resin described above is used as an encapsulating material suitable for an organic light emitting device or the like, preferably, it can be made colorless, odorless, and transparent by removing all double bonds through a hydrogenation reaction, that is, a dicyclopentadiene petroleum resin in a state of being treated with hydrogen can be used.

[0068] On the other hand, preferably, 20 parts by weight to 120 parts by weight of the above-mentioned moisture-resistant petroleum resin can be contained, more preferably, 50 parts by weight to 100 parts by weight of the above-mentioned moisture-resistant petroleum resin can be contained, further more preferably, 60 parts by weight to 90 parts by weight of the above-mentioned moisture-resistant petroleum resin can be contained, most preferably, 70 parts by weight to 80 parts by weight of the above-mentioned moisture-resistant petroleum resin can be contained, based on 100 parts by weight of the above-mentioned encapsulating resin.

[0069] If the above-mentioned moisture-resistant petroleum resin is less than 20 parts by weight, the moisture penetration preventing property can be reduced, and if it is more than 120 parts by weight, the adhesion can be reduced.

[0070] Acrylic acid curing agent

[0071] The first acrylic acid curing agent of the curable composition for encapsulating material of the present application is a monofunctional (meth)acrylate curing agent containing dicyclopentadiene, characterized in that the glass transition temperature is 100°C to 200°C. Specifically, the first acrylic acid curing agent of the present application contains dicyclopentadiene from the viewpoint of improving the adhesion reliability.

[0072] Further, from the viewpoint of improving the durability of the encapsulating material, a monofunctional (meth)acrylate is used, although a difunctional (meth)acrylate curing agent improves the adhesion, but excessively increases the rigidity of the encapsulating material after curing, and when left for a long time under high temperature / high humidity conditions, interface separation, cracks, bubbles and the like appear in the appearance of the encapsulating material, thereby having the problems of reduction in durability and reduction in dilution property, and therefore, a monofunctional (meth)acrylate is selected in order to solve the above-mentioned problems.

[0073] Further, preferably, the glass transition temperature of the first acrylic acid curing agent is 100°C or higher, although it is not particularly limited, but it is preferably 200°C or lower. If the glass transition temperature of the first acrylic acid curing agent is less than 100°C, the moisture absorption property required as a main property of the encapsulating material can be reduced due to the insufficient degree of curing (crosslinking).

[0074] The above-mentioned first acrylic acid curing agent can be used without limitation as long as it satisfies the following conditions: i) contains dicyclopentadiene; ii) is a monofunctional acrylic acid; and iii) the glass transition temperature is 100°C or higher. For example, dicyclopentadiene acrylate (Tg: 110°C), dicyclopentyl acrylate (Tg: 120°C), dicyclopentyl methacrylate (Tg: 175°C) and the like can be used.

[0075] Preferably, 10 to 100 parts by weight of the above-described first acrylic curing agent is contained, more preferably, 30 to 80 parts by weight of the above-described first acrylic curing agent is contained, and most preferably, 40 to 50 parts by weight of the above-described first acrylic curing agent is contained, based on 100 parts by weight of the above-described encapsulating resin.

[0076] If the above-described first acrylic curing agent is less than 10 parts by weight, a problem of poor discharge due to excessively high viscosity can occur, and a problem of reduced reliability and adhesion due to insufficient curing density can occur. If the above-described first acrylic curing agent is more than 100 parts by weight, a problem of poor substrate adhesion due to excessively low viscosity and a problem of reduced reliability due to insufficient relative moisture resistance with respect to the encapsulating resin can occur.

[0077] In addition to the above-described first acrylic curing agent, the curable composition for encapsulating materials of the present application can further include a second acrylic curing agent. The above-described second acrylic curing agent is not an essential component, but is an optional component. The above-described second acrylic curing agent is a difunctional (meth)acrylate curing agent containing dicyclopentadiene, and the glass transition temperature can be 100 to 200°C. Thus, since the second acrylic curing agent is a difunctional (meth)acrylate curing agent, it can be selectively included, and even if it is included, it is preferable to include a small amount. Therefore, the content can be appropriately adjusted within a range in which the effects of the present application are not reduced, for example, preferably, 1 to 5 parts by weight of the above-described second acrylic curing agent can be contained, more preferably, 1 to 3 parts by weight of the above-described second acrylic curing agent can be contained, and most preferably, 2 to 3 parts by weight of the above-described second acrylic curing agent can be contained, based on 100 parts by weight of the above-described encapsulating resin, but can be appropriately contained within a range in which the effects of the present application are not reduced.

[0078] Inorganic moisture absorbent

[0079] In order to improve moisture absorption, the curable composition for encapsulating materials of the present application can further include an inorganic moisture absorbent. The above-described inorganic moisture absorbent can be appropriately selected from inorganic moisture absorbents commonly used in the technical field to which the present application pertains, and for example, calcium oxide, fused silica, crystalline silica, aluminum oxide, calcium carbonate, boron nitride, silicon carbonate, and the like can be used, but are not limited thereto.

[0080] The inorganic moisture absorbent can be adjusted in content based on the total composition of the solid components of the final mixed curable composition for encapsulating materials, for example, based on 100 weight percent of the total solid components of the curable composition for encapsulating materials, and preferably, can be contained in an amount of 35 to 65 weight percent, more preferably, 45 to 60 weight percent, and most preferably, 50 to 60 weight percent. However, the curable composition for encapsulating materials of the present application is a solvent-free type using no solvent, and thus, the total weight of the composition is the same as the total weight of the solid components of the composition.

[0081] If the inorganic moisture absorbent is less than 35 weight percent, there can be a problem in that the service life of the organic electronic device is shortened due to insufficient moisture absorption capacity, and if it is more than 65 weight percent, there can be a problem in that the service life of the organic electronic device is shortened due to excessive expansion when absorbing moisture, and cracks in the encapsulating resin, and the peeling between the substrate and the encapsulating resin can accelerate the penetration of moisture, thereby possibly shortening the service life of the organic electronic device, and there can be a problem in that the appearance is deteriorated when adhering.

[0082] UV initiator

[0083] The curable composition for encapsulating materials of the present application can be a photocurable composition, and can further include a UV initiator which is not sensitive to heat but generates radicals when exposed to chemical rays such as UV. The UV initiator can be appropriately selected from among the UV initiators generally used in the technical field to which the present application pertains, and for example, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (TPO), mono acyl phosphine, bis acyl phosphine, α-hydroxy ketone, α-aminoketone, phenyl glyoxylate, benzyl dimethyl-ketal, and the like can be used, but are not limited thereto.

[0084] Preferably, based on 100 parts by weight of the encapsulating resin, 0.1 to 6.0 parts by weight of the UV initiator can be contained, more preferably, 1.0 to 4.0 parts by weight of the UV initiator can be contained, and most preferably, 1.5 to 2.5 parts by weight of the UV initiator can be contained. If the UV initiator is less than 0.1 parts by weight, there can be a problem in that the heat resistance is not good due to poor UV curing, and if it is more than 6.0 parts by weight, there can be a problem in that the heat resistance is not good due to a decrease in the curing density.

[0085] The curable composition for encapsulation materials of the present invention can be used as a dam material in dam-filling encapsulation processes. When applied to organic light-emitting devices, the dam material can be provided in the form of a liquid composition with a specified viscosity, or in a paste-like form. Therefore, the viscosity of the curable composition for encapsulation materials can vary depending on the application and process of the organic light-emitting device. Preferably, the initial viscosity (Vi) of the curable composition for encapsulation materials of the present invention can be 150,000 mPa·s to 250,000 mPa·s, more preferably, it can be 180,000 mPa·s to 220,000 mPa·s.

[0086] On the other hand, the initial viscosity (V) of the encapsulating material when it is first prepared using a curable composition i The viscosity changes over time, and the lower the change, the better the storage stability and shelf life. Therefore, excellent viscosity stability over time is required as an indicator. Preferably, not only should the viscosity have high stability over time at room temperature (25°C), but also high stability over time at a relatively high temperature of approximately 40°C, considering the heating conditions in subsequent processes used to prepare organic light-emitting devices. From this perspective, the curable composition for encapsulation materials of the present invention satisfies the following relationships 1 and 2.

[0087] Relation 1: [(V 25℃ -V i ) / V i ]×100<1%

[0088] Relation 2: [(V 40℃ -Vi) / V i ]×100<3%

[0089] In relation 1 and relation 2 above, V i V is the initial viscosity. 25℃ V represents the viscosity after being stored at 25°C for 7 days. 40℃ The viscosity is the viscosity after being placed at 40°C for 7 days.

[0090] Hereinafter, a further embodiment of the encapsulation material for an organic light-emitting device according to the present invention will be described in detail.

[0091] Encapsulation materials for organic light-emitting devices

[0092] The encapsulation material for organic light-emitting devices of the present invention can be formed by curing the above-mentioned encapsulation material curable composition.

[0093] After the curable composition for encapsulating material of the present application is prepared, in order to be used as an encapsulating material in an organic light emitting device, a curing reaction is performed, preferably, a photocuring reaction by ultraviolet rays can be performed.

[0094] The encapsulating material for organic light emitting device of the present application is also used in a panel in an organic light emitting device, thus excellent adhesion to the panel is required. In order to evaluate the adhesion to the organic light emitting device, it is known that an adhesion to glass simulation evaluation is performed as a general evaluation method.

[0095] From the viewpoint of ensuring excellent adhesion to the organic light emitting device, the initial adhesion to glass (A i ) of the encapsulating material for organic light emitting device of the present application can be 150 N / cm 2 The above, although the larger the initial adhesion is, the better, from the viewpoint of limiting the upper limit of the adhesion, it can be, for example, 150 N / cm 2 ~ 400 N / cm 2 .

[0096] On the other hand, the initial adhesion (Ai) of the curable composition for encapsulating material at the time of curing and adhesion decreases with the passage of time, electronic products using the organic light emitting device can be placed in severe conditions such as high temperature and high humidity, thus adhesion reliability is required to be excellent under such conditions, and the amount of change in adhesion is small. If the amount of change in adhesion in a severe environment such as high temperature and high humidity is too large, the performance of the electronic product using the organic light emitting device can be significantly reduced.

[0097] Therefore, the encapsulating material for organic light emitting device of the present application can satisfy the following relation 3.

[0098] Relation 3: [(A f -A i ) / A i ] x 100 ≤ 30%

[0099] In the above relation 3, A i is the initial adhesion to glass, and A f is the adhesion after being placed at 85°C for 1000 hours.

[0100] Compared with the prior art, the encapsulating material for organic light emitting device of the present application significantly improves the important characteristic of the encapsulating material, moisture absorption, and further, it is characterized in that the moisture absorption is still excellent in a severe environment such as high temperature and high humidity, which can be evaluated by measuring the length of moisture penetration in an environment where moisture exists.

[0101] Specifically, preferably, the moisture permeation length of the encapsulating material for an organic light emitting device according to the present application after being left at 85°C for 1000 hours can be less than 1.4 mm / 1000 hours, more preferably, can be less than 1.35 mm / 1000 hours, which is a condition for achieving a very excellent moisture permeation prevention characteristic compared to the conventional encapsulating material for an organic light emitting device.

[0102] Hereinafter, the structure and the effect of the present application will be described in more detail through preferred embodiments of the present application. However, this is disclosed only as the preferred embodiments of the present application, and cannot be interpreted as a limitation of the present application regardless of any inclusion above.

[0103] Example 1

[0104] An encapsulating resin was prepared by mixing 100 parts by weight of a second isobutylene resin (Mw: 2500) with respect to 100 parts by weight of a first isobutylene resin (Mw: 10000).

[0105] A curable composition for an encapsulating material was prepared by mixing, based on 100 parts by weight of the above-mentioned encapsulating resin, ① 80 parts by weight of SU-90 (Korea Kumho Industrial Co., dicyclopentadiene petroleum resin / softening point: 85-90°C / hydrogenation treatment o) as a moisture resistant petroleum resin, ② 70 parts by weight of dicyclopentyl methacrylate (Tg: 175°C) as a first acrylate curing agent, ③ 2 parts by weight of an ultraviolet light initiator (TPO), and ④ 30.8 parts by weight of calcium oxide (average particle diameter of 1 μm) as an inorganic moisture absorbent. The above-mentioned mixing was performed using a revolution-revolution agitator (Kurabo Co., KK-2000WE) at a stirring speed of 1000 rpm with defoaming.

[0106] In this case, when the total weight of the curable composition for an encapsulating material is converted into 100 weight percent, the above-mentioned inorganic moisture absorbent is 55 weight percent, and in Example 2 and Comparative Examples 1-7 described below, the inorganic moisture absorbent was also added at the same level (54.5 weight percent-55.5 weight percent) with respect to the total weight of the composition.

[0107] Example 2

[0108] A curable composition for an encapsulating material was prepared in the same manner as in Example 1 above, except that 2 parts by weight of dicyclopentyl dimethylene diacrylate (Tg: 110°C) as a second acrylate curing agent was further included after adding dicyclopentyl methacrylate as a first acrylate curing agent based on 100 parts by weight of the above-mentioned encapsulating resin.

[0109] In order to make the inorganic moisture absorbent 55% by weight, 310 parts by weight of the inorganic moisture absorbent was added instead of 308 parts by weight, in the case of converting the total weight to 100% by weight.

[0110] Comparative Example 1

[0111] A curable composition for a packaging material was prepared in the same manner as in Example 1 except that 15 parts by weight of dicyclopentadiene petroleum resin was contained instead of 80 parts by weight. 229 parts by weight of inorganic moisture absorbent was contained instead of 308 parts by weight.

[0112] Comparative Example 2

[0113] A curable composition for a packaging material was prepared in the same manner as in Example 1 except that 15 parts by weight of dicyclopentadiene petroleum resin was contained instead of 80 parts by weight. 229 parts by weight of inorganic moisture absorbent was contained instead of 308 parts by weight.

[0114] Comparative Example 3

[0115] A curable composition for a packaging material was prepared in the same manner as in Example 1 except that 125 parts by weight of dicyclopentadiene petroleum resin was contained instead of 80 parts by weight. 363 parts by weight of inorganic moisture absorbent was contained instead of 308 parts by weight.

[0116] Comparative Examples 4 to 7

[0117] A curable composition for a packaging material was prepared in the same manner as in Example 1 except that the petroleum resin belonging to dicyclopentadiene petroleum resin of SU-90 was used instead of the petroleum resin of Table 1 below as a moisture resistance petroleum resin.

[0118] Table 1

[0119]

[0120] For the curable compositions for a packaging material prepared in Examples 1 to 2 and Comparative Examples 1 to 7 above, measurement and evaluation were performed according to Experimental Examples 1 to 7 below, and the results are shown in Tables 2 to 4 below.

[0121] Experimental Example 1: Measurement of Viscosity

[0122] For the curable compositions for a packaging material, viscosity was measured using an E-type Cone-Plate Type viscometer (Toki-sangyo Co., Ltd., TV E-35H) under conditions of 25°C and 2.5 rpm.

[0123] Experimental Example 2: Evaluation of Viscosity Stability over Time

[0124] The initial viscosity (Vi) was measured using a Cone-Plate Type E viscometer (Toki-sangyo, TVE-35H) at 25°C and 2.5 rpm. The viscosity V was then measured under the same conditions after 7 days of storage at 25°C and 40°C, respectively, and used as the subsequent viscosity. 25℃ and V 40℃ .

[0125] The initial viscosity (V) was measured respectively. i V, as the viscosity thereafter 25℃ and V 40℃ After substituting into the following calculation formulas 1 and 2, evaluate the viscosity stability over time based on the calculated rate of change.

[0126] - Calculation formula 1: [(V 25℃ -V i ) / V i ]×100(%)

[0127] - Calculation formula 2: [(V 40℃ -V i ) / V i ]×100(%)

[0128] According to the result of the above calculation formula 1, if it is less than 1%, it is evaluated as good (○); if it is greater than or equal to 1% and less than 2%, it is evaluated as average (△); if it is greater than or equal to 2%, it is evaluated as poor (×).

[0129] Based on the result of the above calculation formula 2, if it is less than 3%, it is evaluated as good (○); if it is greater than or equal to 3% and less than 5%, it is evaluated as average (△); and if it is greater than or equal to 5%, it is evaluated as poor (×).

[0130] Experiment Example 3: Measuring Adhesive Force

[0131] After applying 1 mg of the curing composition for encapsulation material to alkali-free glass A (100 mm × 50 mm × 0.7 t), alkali-free glass B (100 mm × 50 mm × 0.7 t) is arranged in a cross pattern relative to alkali-free glass A, and pressure is applied until the thickness of the curing composition reaches 20 μm to 30 μm. In this case, the curing composition is positioned precisely in the center of alkali-free glass A and alkali-free glass B. Ultraviolet light with a wavelength of 365 nm and a concentration of 3000 mJ / cm² is used. 2 The sample is cured by irradiation under pressure, thereby bonding alkali-free glass A and alkali-free glass B together.

[0132] The initial adhesive force (Ai) of the above-mentioned bonded specimens was measured using a universal testing machine (UTM) in compression mode at a speed of 5 mm / min.

[0133] Experimental Example 4: Evaluation of Adhesion Reliability

[0134] The initial adhesion force (A i ) measured in Experimental Example 3 above and the adhesion force (A f ) of the sample after leaving the sample of Experimental Example 3 above in a reliability evaluation chamber set to 85°C and 85% relative humidity for 1000 hours were substituted into the following calculation formula 3 to calculate the change rate based on the calculation, and the adhesion reliability was evaluated.

[0135] - Calculation Formula 3: [(A f - A i ) / A i ] x 100 (%)

[0136] According to the result value of the above calculation formula 3, if it is equal to or less than 30%, it is evaluated as good (O), if it is greater than 30% and equal to or less than 50%, it is evaluated as ordinary (Δ), and if it is greater than 50%, it is evaluated as poor (X).

[0137] Experimental Example 5: Measurement of Water Penetration Length

[0138] After applying 1 mg of the encapsulant-use curable composition to the center of the non-alkali glass A (50 mm x 50 mm x 0.7 t), the non-alkali glass B (50 mm x 50 mm x 0.7 t) was pressed until the thickness reached a level of 20 μm to 30 μm. The pressed sample was irradiated with ultraviolet rays having a wavelength of 365 nm at 3000 mJ / cm 2 to cure, thereby adhering the non-alkali glass A and the non-alkali glass B to each other.

[0139] After leaving the above adhered sample in a reliability evaluation chamber set to 85°C and 85% relative humidity for 1000 hours, the length (mm) of water penetration into the above sample was measured using a microscope.

[0140] Experimental Example 6: Evaluation of Durability

[0141] After applying 1 mg of the encapsulant-use curable composition to the center of the non-alkali glass A (50 mm x 50 mm x 0.7 t), the non-alkali glass B (50 mm x 50 mm x 0.7 t) was pressed until the thickness reached a level of 20 μm to 30 μm. The pressed sample was irradiated with ultraviolet rays having a wavelength of 365 nm at 3000 mJ / cm 2 to cure, thereby adhering the non-alkali glass A and the non-alkali glass B to each other.

[0142] After the above adhered sample was left in a reliability evaluation chamber set to 85°C and 85% relative humidity for 1000 hours, the appearance of the sample was observed using a microscope.

[0143] The results of the microscopic observation were that if the appearance of the sample was normal, the evaluation was good (O), and if any abnormality such as interface separation, cracks, and bubbles occurred, the evaluation was bad (X).

[0144] Experimental Example 7: Evaluation of adhesiveness after curing

[0145] After the syringe was filled with the encapsulating material-curing composition filler, the alkaline-free glass A (100 mm x 100 mm x 0.7 t) was adhered in a rectangular form (80 mm x 80 mm) using an automatic injector (Musashi Co., CM III-V5) device (in this case, the application amount was adjusted so that the width was 3 mm to 4 mm and the thickness was 20 μm to 30 μm after adhesion), and the alkaline-free glass B (100 mm x 100 mm x 0.7 t) was overlaid thereon, followed by pressurization in a vacuum. Ultraviolet rays having a wavelength of 365 nm were irradiated at 3000 mJ / cm2using an ultraviolet irradiator, and the sample was left to stand for 1 hour. 2 The pressurized sample was irradiated and cured, whereby the alkaline-free glass A and the alkaline-free glass B were adhered to each other.

[0146] The appearance of the above adhered sample was observed using a microscope, and the adhesiveness was evaluated.

[0147] The results of the microscopic observation were that if the appearance of the sample was normal, the evaluation was good (O), and if any abnormality such as uneven line width, wrinkles, and streaks occurred, the evaluation was bad (X).

[0148] Table 2

[0149]

[0150] Table 3

[0151]

[0152] Table 4

[0153]

[0154] The above describes the present application with reference to the illustrated examples, but the present application is not limited to the examples disclosed in the present specification, and it should be apparent to those skilled in the art to which the present application pertains that various modifications can be made within the scope of the technical idea of the present application. Also, even if the effects of the structure of the present application are not explicitly shown in the above description of the examples of the present application, effects that can be predicted from the related structure should be recognized.

Claims

1. A curable composition for encapsulation materials, characterized in that, Include: The encapsulating resin comprises two isobutylene resins with different molecular weights. Moisture-resistant petroleum resins; and First acrylic curing agent, The above-mentioned isobutylene resin is represented by the following chemical formula (1), comprising a first isobutylene resin with a molecular weight of 5000 Mw to 50000 Mw and a second isobutylene resin with a molecular weight of 800 Mw to 4000 Mw. Based on 100 parts by weight of the first isobutylene resin, the encapsulating resin comprises 10 to 300 parts by weight of the second isobutylene resin. The aforementioned moisture-resistant petroleum resin is a dicyclopentadiene petroleum resin with a softening point of 60℃~100℃. Chemical formula (1): In the above chemical formula (1), n ​​is an integer greater than or equal to 1.

2. The curable composition for encapsulation materials according to claim 1, characterized in that, The above-mentioned dicyclopentadiene petroleum resin was hydrogenated.

3. The curable composition for encapsulation materials according to claim 1, characterized in that, Based on 100 parts by weight of the above-mentioned encapsulating resin, it includes 20 to 120 parts by weight of the above-mentioned moisture-resistant petroleum resin.

4. The curable composition for encapsulation materials according to claim 1, characterized in that, The aforementioned first acrylic curing agent is a monofunctional (meth)acrylate curing agent containing dicyclopentadiene, with a glass transition temperature of 100℃~200℃. Based on 100 parts by weight of the above-mentioned encapsulating resin, it contains 10 to 100 parts by weight of the above-mentioned first acrylic curing agent.

5. The curable composition for encapsulation materials according to claim 1, characterized in that, It also contains a second acrylic curing agent. The aforementioned second acrylic curing agent is a difunctional (meth)acrylate curing agent containing dicyclopentadiene, with a glass transition temperature of 100℃~200℃.

6. The curable composition for encapsulation materials according to claim 5, characterized in that, Based on 100 parts by weight of the above-mentioned encapsulating resin, it contains 1 to 5 parts by weight of the above-mentioned second acrylic curing agent.

7. The curable composition for encapsulation materials according to claim 1, characterized in that, It also contains inorganic desiccant.

8. The curable composition for encapsulation materials according to claim 7, characterized in that, Based on the total solids content of the curable composition for the above-mentioned encapsulation material at 100% by weight, it contains 35% to 65% by weight of the above-mentioned inorganic desiccant.

9. The curable composition for encapsulation materials according to claim 1, characterized in that, It also contains a UV photoinitiator.

10. The curable composition for encapsulation materials according to claim 1, characterized in that, Initial viscosity V i The range is 150,000 mPa•S to 250,000 mPa•S.

11. The curable composition for encapsulation materials according to claim 1, characterized in that, Satisfying the following relations 1 and 2: Relation 1: [(V 25℃ -V i ) / V i ]×100<1% Relation 2: [(V 40℃ -V i ) / V i ]×100<3% In relation 1 and relation 2 above, V i V is the initial viscosity. 25℃ V represents the viscosity after being stored at 25°C for 7 days. 40℃ The viscosity is the viscosity after being placed at 40°C for 7 days.

12. An encapsulation material for organic light-emitting devices, characterized in that, The encapsulation material according to any one of claims 1 to 11 is formed by curing the curable composition.

13. The encapsulation material for organic light-emitting devices according to claim 12, characterized in that, Initial adhesive force A on glass i 150 N / cm 2 ~400N / cm 2 .

14. The encapsulation material for organic light-emitting devices according to claim 12, characterized in that, The following relation 3 must be satisfied: Relation 3: [(A f -A i ) / A i ]×100≤30% In relation 3 above, A i For the initial adhesive force on the glass, A f The adhesive strength is measured after being placed at 85°C for 1000 hours.

15. The encapsulation material for organic light-emitting devices according to claim 12, wherein the water penetration length after being placed at 85°C for 1000 hours is less than 1.4 mm / 1000 hours.

16. An organic light-emitting device, characterized in that, The encapsulation material for organic light-emitting devices according to any one of claims 12 to 15 is used.

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