KR20230083461A - Dam material composition for image display apparatus, dam structure formed therefrom and image display apparatus including dam structure - Google Patents

Abstract

A dam material composition for an image display device, a dam structure formed therefrom, and an image display device including the dam structure are disclosed. The disclosed dam material composition for an image display device includes an acrylate-based compound having a form of at least one of a monomer and an oligomer; A urethane diacrylate-based compound having a repeating unit containing a urethane group; curing initiators; and getters; The urethane diacrylate-based compound may include a butadiene group. The dam material composition for the image display device may further include a butadiene urethane diacrylate-based compound.

Description

Dam material composition for image display device, dam structure formed therefrom and image display device including dam structure {Dam material composition for image display apparatus, dam structure formed therefrom and image display apparatus including dam structure}

The present invention relates to a resin composition and a member and device to which the same is applied, and more particularly, to a dam material composition for an image display device, a dam structure formed therefrom, and an image display device including the dam structure.

An image display device, that is, a display device is developing in a direction of reducing thickness and increasing (equipped with) transparency. Recently, a flexible/bendable display device has been developed, and interest in a feature capable of transforming a size or shape is increasing. In line with this direction of development, a bezel applied to a display device is also being replaced with a narrow area, transparent, and flexible material. In particular, in the field of organic light emitting diode (OLED) displays, protection and reliability of organic light emitting materials may be important tasks. When an OLED display is implemented as a flexible/bendable device, if deformation is applied by an external force, a large amount of force is concentrated on the sealing part, that is, the dam part of the display, resulting in defects such as cracks. It can be a pathway for oxygen and moisture to permeate. Organic light-emitting materials can be relatively easily deteriorated/damaged by penetration of oxygen or moisture. Accordingly, it is required to develop a material for a display sealing part, that is, a dam material, in line with the direction of development of display devices.

Existing dam materials are generally manufactured with a focus on water barrier properties, and have low transmittance and high turbidity from an optical point of view. In addition, existing dam materials have a problem in that adhesion (adhesion strength) is relatively weak. Since the display of a rigid substrate is hardly deformed by an external force, the adhesive strength of a dam material may not be greatly required. However, in a display device that is deformed by an external force, such as a flexible/bendable/foldable portable device or an ultra-thin TV (eg, a rollable TV), the adhesion of a dam material can be an important factor in securing reliability and durability. Therefore, in accordance with the development and change direction of display devices, there is a demand for the development of dam materials capable of securing optical properties such as transparency while simultaneously securing excellent adhesion and oxygen/moisture barrier properties.

A technical problem to be achieved by the present invention is to provide a dam material composition for an image display device that can secure optical properties such as transparency while simultaneously securing excellent adhesion and oxygen/moisture barrier properties.

In addition, a technical problem to be achieved by the present invention is to provide a dam structure formed from the above dam material composition and an image display device including the dam structure.

The problem to be solved by the present invention is not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

A dam material composition for an image display device according to an aspect of the present invention includes an acrylate-based compound having a form of at least one of a monomer and an oligomer; A urethane diacrylate-based compound having a repeating unit containing a urethane group; curing initiators; and getters;

The dam material composition for the image display device includes 7 to 80% by weight of the acrylate-based compound; 7 to 90% by weight of the urethane diacrylate-based compound; 0.05 to 5% by weight of the curing initiator; and 0.1 to 40% by weight of the getter.

In addition, the repeating unit of the urethane diacrylate-based compound may further include a chain hydrocarbon structure having 2 or more carbon atoms.

The repeating unit of the urethane diacrylate-based compound may further include a cycloalkyl group.

In addition, the urethane diacrylate-based compound may be represented by Formula 1 below.

[Formula 1]

(A and A` independently include an acrylate group or a methacrylate group, R includes a chain hydrocarbon structure having 1 or more carbon atoms, R′ includes a cycloalkyl group, and m is 1 ~ 50,000)

In this case, A and R are connected by a urethane bond, A′ and R′ are connected by a urethane bond, and R is -O-CH ₂ -(CH ₂ ) _n -CH ₂ -including a group can do.

At least some of the urethane diacrylate-based compounds may be represented by Formula 2 below.

[Formula 2]

(The R _A includes a hydroxyalkyl acrylate, the R _I includes an alicyclic structure or a cyclic alicyclic structure, the R _P includes an alkyl or unsaturated alkyl structure, and the m is 1 to 50,000 am)

In this case, R _A includes any one selected from the group consisting of hydroxyethyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl acrylate, and R _I is toluene, diphenylmethane, tetramethylene, xyl includes any one selected from the group consisting of rene, isophorone, dicyclohexylmethane and hexamethylene, and R _P is any one selected from the group consisting of polyether, polyester, polycaprolactone, polycarbonate and alkyl polyol can include

The urethane diacrylate-based compound may have a form of at least one of an oligomer and a polymer.

The urethane diacrylate-based compound may have a weight average molecular weight of 300 to 300,000.

The acrylate-based compound may include at least one of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, isobornyl acrylate, and vinyl acrylate.

The urethane diacrylate-based compound may include a butadiene group.

The dam material composition may further include a butadiene urethane diacrylate-based compound.

In this case, the content of the butadiene urethane diacrylate-based compound may be 5 to 20% by weight of the total content of the urethane diacrylate-based compound.

The dam material composition may further include at least one of a filler, a spacer, and an additive.

The viscosity of the dam material composition may be 70,000 to 350,000 cP.

The dam material composition may have an adhesive strength of 1.5 kgf/cm ² or more, and specifically, an adhesive strength of 2.0 kgf/cm ² or more.

The dam material composition may include an epoxy-based compound and may further include a curing agent for the epoxy-based compound.

The getter may include a metal oxide or an organic getter capable of absorbing moisture.

An image display device according to another aspect of the present invention includes a display element substrate; an encapsulation layer member disposed on the display element substrate; and a dam structure provided for sealing between the display element substrate and the encapsulation layer member and formed from the dam material composition described in the present invention.

According to the embodiments of the present invention, in manufacturing an image display device (display device), excellent adhesive strength and oxygen / moisture blocking properties are secured at the same time, as well as optical properties such as transparency. Dam material for an image display device capable of securing A dam material composition can be implemented.

Using the dam material composition according to the embodiment, an image display device having excellent reliability and durability can be manufactured. In particular, the dam material composition according to the embodiment can be usefully applied to the manufacture of deformable image display devices such as flexible/bendable/foldable.

1 is a diagram for explaining the configuration of a dam material composition for an image display device according to an embodiment of the present invention.
2 is a cross-sectional view exemplarily showing an image display device to which a dam structure formed from a dam material composition according to an embodiment of the present invention is applied.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Embodiments of the present invention to be described below are provided to more clearly explain the present invention to those skilled in the art, and the scope of the present invention is not limited by the following examples, Embodiments may be modified in many different forms.

Terms used in this specification are used to describe specific embodiments and are not intended to limit the present invention. Terms in the singular form used herein may include plural forms unless the context clearly indicates otherwise. Also, as used herein, the terms "comprise" and/or "comprising" specify the presence of the stated shape, step, number, operation, member, element, and/or group thereof. and does not exclude the presence or addition of one or more other shapes, steps, numbers, operations, elements, elements and/or groups thereof. In addition, the term “connection” used in this specification means not only direct connection of certain members, but also a concept including indirect connection by intervening other members between the members.

In addition, when a member is said to be located “on” another member in the present specification, this includes not only a case where a member is in contact with another member, but also a case where another member exists between the two members. As used herein, the term “and/or” includes any one and all combinations of one or more of the listed items. In addition, terms of degree such as "about" and "substantially" used in the present specification are used in a range of values or degrees or meanings close thereto, taking into account inherent manufacturing and material tolerances, and are used to help the understanding of the present application. Exact or absolute figures provided for this purpose are used to prevent undue exploitation by infringers of the stated disclosure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The size or thickness of areas or parts shown in the accompanying drawings may be slightly exaggerated for clarity of the specification and convenience of description. Like reference numbers indicate like elements throughout the detailed description.

1 is a diagram for explaining the configuration of a dam material composition for an image display device according to an embodiment of the present invention.

Referring to FIG. 1, the dam material composition for an image display device according to the present embodiment includes an acrylate-based compound 10, a urethane diacrylate-based compound 20, and a curing initiator. (curing initiator) 30 and getter 40 are included.

The acrylate-based compound 10 has at least one form of a monomer (monomer) and an oligomer (oligomer).

The urethane diacrylate-based compound 20 has a repeating unit containing a urethane group, and may have a form of at least one of an oligomer and a polymer. If the urethane group is not included in the repeating unit and exists only at the end of the compound, the desired adhesive strength of the dam material cannot be obtained. Therefore, the urethane diacrylate-based compound must contain a urethane group in a repeating unit.

The curing initiator 30 may be activated by light or heat to cause a polymerization reaction between the acrylate-based compound 10 and the urethane diacrylate-based compound 20 . The polymerization reaction may be induced while generating radicals of acrylate. The curing initiator 30 may be, for example, a UV (ultraviolet) curing type photo-initiator. In this case, the curing initiator 30 may be a cationic initiator. However, in some cases, the curing initiator 30 may be a thermally curable initiator or a type activated by both UV and heat.

The getter 40 has a property of absorbing moisture and can be made of organic and inorganic materials. Among inorganic materials, a metal oxide material may be used, and more specifically, CaO, MgO, ZrO ₂ , TiO ₂ , Al ₂ O ₃ and the like may be used. On the other hand, the water absorption ability and optical properties may be affected according to their particle size. The size of the getter may vary from several tens of micrometers to several tens of nanometers.

Although not shown, the dam material composition may further include other materials in addition to the acrylate-based compound 10, the urethane diacrylate-based compound 20, the curing initiator 30, and the getter 40. Other materials will be described in more detail later with reference to Table 2 and the like.

Table 1 below summarizes the composition of a dam material composition for an image display device according to an embodiment of the present invention.

composition type Form / Remarks Acrylate-based compounds 2-hydroxyethyl acrylate
2-hydroxyethyl methacrylate
isobornyl acrylate
vinyl acrylate monomer and/or oligomer Urethane diacrylate-based compound urethane diacrylate
urethane dimethacrylate oligomer and/or polymer cure initiator cationic initiator Generation of radicals in acrylate getter CaO Powder Nano-scale, Metal Oxide available (MgO ZrO ₂ , TiO ₂ , Al ₂ O ₃ , etc.)

In the dam material composition according to the embodiment, the urethane diacrylate-based compound may be aliphatic urethane diacrylate. The urethane diacrylate-based compound may serve to improve the adhesion of the dam material composition and increase the viscosity of the entire dam material composition (ie, resin) within an appropriate range. In addition, the urethane diacrylate-based compound may also act advantageously in terms of optical properties such as securing transparency.

Meanwhile, the acrylate-based compound may have a hydrophobic property while having the form of a monomer and/or an oligomer, and in this regard, may serve to improve moisture suppression and functionality of a dam material. In addition, similar to the urethane diacrylate-based compound, the acrylate-based compound may also act advantageously in securing transparency.

The dam material composition according to the embodiment includes 7 to 80% by weight of the acrylate-based compound; 7 to 90% by weight of the urethane diacrylate-based compound; 0.05 to 5% by weight of the curing initiator; and 0.1 to 40% by weight of the getter. When these mixing ratio conditions are satisfied, it may be advantageous to secure excellent adhesion, oxygen/moisture barrier properties, and optical properties (transparency, etc.).

In the urethane diacrylate-based compound, the repeating unit containing the urethane group may further include a chain-type hydrocarbon structure having 2 or more carbon atoms, and this chain-type hydrocarbon structure is a bridge-type chain-type polyol can also be configured. In addition, the repeating unit in the urethane diacrylate-based compound may further include a cycloalkyl group. The urethane diacrylate-based compound may have at least one form of an oligomer and a polymer.

The urethane diacrylate-based compound may be represented by Formula 1 below.

In Formula 1, A and A′ independently include an acrylate group or a methacrylate group, R includes a chain hydrocarbon structure having 1 or more carbon atoms, and R′ includes a cycloalkyl group, The m is 1 to 50,000. More specifically, R may include a chain hydrocarbon structure having 3 to 20 carbon atoms, and m may be 1 to 3,000. When m is 1 or more, the desired adhesion of the dam material can be obtained.

Here, A and R may be connected by a urethane bond, A` and R` may be connected by a urethane bond, and R is -O-CH ₂ -(CH ₂ ) _n -CH ₂ - may include a group. In this case, n may be about 1 to several tens.

At least some of the urethane diacrylate-based compounds may be represented by Formula 2 below.

In Formula 2, R _A includes hydroxyalkyl acrylate, R _I includes an alicyclic structure or a cyclic alicyclic structure, R _P includes an alkyl or unsaturated alkyl structure, and m may be from 1 to 50,000, and more specifically from 1 to 3,000. For reference, the urethane diacrylate-based compound can be synthesized to have a weight average molecular weight of about 1,000,000, but problems may occur in commercial aspects, it is difficult to obtain reproducibility, and the viscosity rises rapidly, so that other materials (viscosity Since fairness must be obtained using a low material), considering practical aspects, the weight average molecular weight of the urethane diacrylate-based compound can be used by appropriately adjusting the m, and more specifically, 1,000 to 300,000 200,000 may be used, but is not limited thereto.

More specifically, R _A may include any one selected from the group consisting of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, and the like, and R _I is toluene, diphenylmethane , may include any one selected from the group consisting of tetramethylene, xylene, isophorone, dicyclohexylmethane and hexamethylene, etc., R _P is polyether, polyester, polycaprolactone, polycarbonate and alkyl polyol It may include any one selected from the group consisting of and the like.

Adhesion may be improved only by the introduction of the urethane diacrylate-based compound. In addition, as the molecular weight of the urethane diacrylate-based compound increases, adhesion may additionally increase. However, the range of change is not greatly increased. However, as the molecular weight increases, the reliability of the dam material at high temperature and high humidity (85℃-85RH%) increases. That is, when a urethane diacrylate-based compound having a high weight average molecular weight is applied, adhesion reliability is excellent under high temperature and high humidity conditions. The reason for this is that, in general, as the weight average molecular weight of polymers increases, Tg increases, which means that polymers can remain stable under high temperature conditions.

Meanwhile, in FIG. 1 and Table 1, the acrylate-based compound may include, for example, at least one of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, isobornyl acrylate, and vinyl acrylate. They may have hydrophobic properties and may serve to enhance moisture retention and functionality.

Formulas 3 to 6 below show the chemical structures of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, isobornyl acrylate and vinyl acrylate.

Formula 3 is the chemical structure of 2-hydroxyethyl acrylate.

Chemical Formula 4 is the chemical structure of 2-hydroxyethyl methacrylate.

Chemical Formula 5 is the chemical structure of isobornyl acrylate.

Chemical Formula 6 is the chemical structure of vinyl acrylate.

Referring to Chemical Formulas 3 to 6, acrylate-based compounds that can be applied to the examples have been specifically disclosed, but these are exemplary, and acrylate-based compounds having other structures/configurations may be used.

In the dam material composition according to the present invention, the getter may be included in about 0.1 to 40% by weight. When these numerical ranges are satisfied, oxygen/moisture barrier properties may be secured.

The dam material composition according to the present invention may include a curing initiator in an amount of 0.05 to 5% by weight. Through this, the dam structure of the display device can be formed by curing the dam material composition of the present invention. If the content of the curing initiator is less than the above content range, there may be a problem that the composition is not cured, and if the content of the curing initiator exceeds the above content range, the adhesive properties required for the dam structure, moisture barrier properties, etc. are deteriorated problems can arise.

The dam material composition according to an embodiment of the present invention may further include other materials in addition to the acrylate-based compound, the urethane diacrylate-based compound, the curing initiator, and the getter. The other materials may be, for example, fillers, spacers, additives, and the like. The configuration of the dam material composition for an image display device according to the embodiment including the other materials may be summarized in Table 2 below.

composition type Form / Remarks Epoxy-based compound 3,4-Epoxycyclohexylmethyl Diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate
1,4-Cyclohexanedimethanol diglycidyl ether
3,4-Epoxycyclohexylmethyl Methacrylate
Trimethylolpropane triglycidyl ether
Tris(2,3-epoxypropyl) isocyanurate Monomer or oligomer Acrylate-based compounds 2-hydroxyethyl acrylate2-hydroxyethyl methacrylate
isobornyl acrylate
vinyl acrylate monomer and/or oligomer Urethane diacrylate-based compound urethane diacrylate
urethane dimethacrylate oligomer and/or polymer cure initiator cationic initiator Creation of cations in epoxies radical initiator Generation of radicals in acrylate getter CaO Powder Nano-scale, Metal Oxide available (MgO ZrO ₂ , TiO ₂ , Al ₂ O ₃ , etc.) filler silica (Fumed silica) spacer polymer bead

Since the acrylate-based compound, the urethane diacrylate-based compound, and the curing initiator in Table 2 may be the same as or similar to those described with reference to FIGS. 1 and 1, repeated description thereof is excluded.

In Table 2, the filler may serve to impart thixotropy to the fluid (ie, the dam material composition). Thixotropy refers to a phenomenon in which viscosity decreases when a shear force such as stirring a liquid substance acts, and increases when the shear force does not act. Thixotropy can be imparted to a fluid by using a filler, and the degree of thixotropy can be adjusted. For the process of forming a dam structure using the dam material composition, thixotropy corresponding to a level of about 2.5 may be appropriate. The filler may include, for example, silica particles, and the silica particles may be fumed silica. These silica particles may serve to increase the specific surface area in the dam material composition, and may also have a moisture suppression effect.

The spacer may play a role of maintaining a constant interval of the gap space in which the dam structure is formed. The spacer may include a relatively hard material, eg, a plurality of polymer beads having a relatively hard property. The polymer beads may have a diameter corresponding to or similar to the spacing of the gap space in which the dam structure is formed. For example, the polymer beads may have a diameter of about several μm to several tens of μm, for example, about 10 μm. These polymer beads may be disposed along the extension direction within the dam structure. Therefore, the polymer beads may serve to maintain a gap between attachments on both sides of the dam structure. A 'hard' characteristic may be partially imparted to the dam structure by the spacer, and a 'soft' characteristic may be imparted to the dam structure by the remaining polymeric materials excluding the spacer.

When the dam material composition according to the embodiment has the configuration shown in Table 2, here, the epoxy-based compound may have a content of about 5 to 55% by weight, and the acrylate-based compound may have a content of about 5 to 90% by weight content, the urethane diacrylate-based compound may have a content of about 5 to 90% by weight, the curing initiator may have a content of about 0.05 to 5% by weight, and the getter may have a content of about 0.005 to 30% by weight The content of the filler may be about 0.1 to about 10% by weight, and the spacer may have about 0.01 to about 3% by weight. When having such a content ratio, it may be advantageous to implement excellent properties.

Among them, the epoxy-based compound may be used for the purpose of further supplementing the moisture barrier properties of the getter, but may be included within the above content range to effectively exhibit adhesive properties and moisture barrier properties, but is not limited thereto.

In addition, when an epoxy-based compound is used, a cationic initiator for curing an epoxy-based compound and a radical initiator for curing an acryl-based compound may be used together as a curing initiator. In general, the initiator of the two compounds may be included in an amount of 0.05 to 5% by weight compared to the compound. The weight ratio of these initiators may be used in proportion to the weight ratio of each epoxy-based compound and acrylic compound, but is not limited thereto.

The dam material composition according to the above embodiment may have a relatively high adhesive strength (adhesive force) of about 2.0 kgf/cm ² or more. This can be said to be significantly improved compared to the conventional dam material composition having an adhesive strength (adhesive force) of about 1.5 to 1.7 kgf/cm ² . In addition, the dam material composition according to the above embodiment may have a viscosity of about 70,000 cP to about 350,000 cP. It may be advantageous to secure excellent processability and excellent properties by the viscosity increasing effect. In addition, the dam material composition according to the above embodiment may have thixotropy that is advantageous to the process. In addition, when the dam material composition according to the above embodiment is used, control/adjustment of viscosity and thixotropy can be easily performed. The dam material composition according to the above embodiment may be a 'solvent-free type', and it may be possible to secure and adjust the above-mentioned physical properties without using a solvent. However, depending on the case, a small amount of solvent (solvent) may be included in the dam material composition.

On the other hand, when the weight average molecular weight of urethane diacrylate is 100,000 or more, the viscosity of the material may increase, and when an excessive amount of getter is included for blocking moisture, the increase in viscosity may increase rapidly. Therefore, when using urethane diacrylate having a weight average molecular weight of 100,000 or more, the viscosity of the entire dam material composition can be adjusted by appropriately using an acrylate-based compound having a viscosity of 500 cP or less, preferably 50 cP or less. Urethane diacrylate may have a viscosity of 1,000 cP or more and 1,000,000 cP or less, but may be appropriately selected and used in consideration of the viscosity of the entire dam material composition. However, when an excessive amount of the acrylate-based compound is added, the viscosity is too low, and the DAM width cannot be adjusted to the target thickness after bonding when the dam material composition is applied. In addition, since the adhesive strength is relatively lower than that of urethane diacrylate, if an excessive amount is added, the adhesive strength may be reduced. Therefore, the content of the dam material composition may be appropriately adjusted so that the viscosity of the dam material composition may be about 70,000 to 350,000 cP.

The viscosity value in the present invention means the kinematic viscosity value measured under 2.5 RPM and room temperature conditions through a rheometer.

In addition, the dam material composition according to the above embodiment may have excellent optical transparency, and a dam structure manufactured therefrom may also have excellent transparency. Such optical characteristics may be advantageously applied to the implementation of a transparent display device or a light transmissive display device.

According to another embodiment of the present invention, in the embodiment described with reference to FIG. 1, Table 1 and Table 2, etc., the urethane diacrylate-based compound may further include a butadiene group. Here, the urethane diacrylate-based compound containing the butadiene group may be represented by, for example, Formula 7 or Formula 8 below.

일 수 있다. 이때, l은 1 이상의 정수일 수 있고, m은 1 이상의 정수일 수 있으며, n은 1 이상의 정수일 수 있다.In Formula 7, R _A , R _I , and R _P are defined as in Formula 2, and R _B is

can be In this case, l may be an integer greater than or equal to 1, m may be an integer greater than or equal to 1, and n may be an integer greater than or equal to 1.

일 수 있다. 이때, l은 1 이상의 정수일 수 있고, m은 1 이상의 정수일 수 있으며, n은 1 이상의 정수일 수 있다.In Formula 8, the definitions of R _A , R _I , and R _P are the same as in Formula 2, and R _B' is

can be In this case, l may be an integer greater than or equal to 1, m may be an integer greater than or equal to 1, and n may be an integer greater than or equal to 1.

The butadiene group may serve to improve properties such as moisture suppression and adhesion of the dam material composition. However, the butadiene group may cause some haze to lower transparency. Therefore, considering the transparency characteristics required in the display device, it is possible to determine whether or not the butadiene group is included or not.

Meanwhile, according to another embodiment of the present invention, the dam material composition further includes a "butadiene urethane diacrylate-based compound" in addition to the acrylate-based compound, the urethane diacrylate-based compound, and the curing initiator can do. The composition of the dam material composition for an image display device according to this embodiment may be summarized in Table 3 below.

composition type Form / Remarks Acrylate-based compounds 2-hydroxyethyl acrylate
2-hydroxyethyl methacrylate
isobornyl acrylate
vinyl acrylate monomer and/or oligomer Urethane diacrylate-based compound urethane diacrylate
urethane dimethacrylate oligomer and/or polymer Butadiene urethane diacrylate-based compound butadiene urethane diacrylate
butadiene urethane dimethacrylate oligomer and/or polymer cure initiator cationic initiator Generation of radicals in acrylate getter CaO Powder Nano-scale, Metal Oxide available (MgO ZrO ₂ , TiO ₂ , Al ₂ O ₃ , etc.)

In Table 3, the acrylate-based compound, the urethane diacrylate-based compound, and the curing initiator may be the same as those described above, and additionally, a butadiene urethane diacrylate-based compound may be further included. The butadiene urethane diacrylate-based compound may have a form of at least one of an oligomer and a polymer, and may include, for example, at least one of butadiene urethane diacrylate and butadiene urethane dimethacrylate. The butadiene urethane diacrylate-based compound may serve to improve properties such as moisture suppression and adhesion of the dam material composition. However, the butadiene urethane diacrylate-based compound may lower transparency by generating some haze. Therefore, it is possible to determine whether or not to add the butadiene urethane diacrylate-based compound or the like in consideration of the transparency characteristics required for the display device.

For example, in the dam material composition according to the embodiment, the content of the butadiene urethane diacrylate-based compound may be 5 to 20% by weight of the total content of the urethane diacrylate-based compound. When the content of the butadiene urethane diacrylate-based compound is less than the above numerical range, it is difficult to expect further improvement in the water barrier effect, and when it exceeds the above numerical range, miscibility with other acrylate-based compounds used together is reduced. As a result, a problem of deterioration in optical properties such as transparency may occur.

In the dam material composition according to the embodiment, the getter may be included in about 0.1 to 40% by weight. When these numerical ranges are satisfied, oxygen/moisture barrier properties may be secured.

The dam material composition according to an embodiment of the present invention may further include other materials in addition to the acrylate-based compound, the urethane diacrylate-based compound, the butadiene urethane diacrylate-based compound, the curing initiator, and the getter. The other materials may be, for example, fillers, spacers, additives, and the like. The configuration of the dam material composition for an image display device according to the embodiment including the other materials may be summarized in Table 4 below.

composition type Form / Remarks Acrylate-based compounds 2-hydroxyethyl acrylate
2-hydroxyethyl methacrylate
isobornyl acrylate
vinyl acrylate monomer and/or oligomer Urethane diacrylate-based compound urethane diacrylate
urethane dimethacrylate oligomer and/or polymer Butadiene urethane diacrylate-based compound butadiene urethane diacrylate
butadiene urethane dimethacrylate oligomer and/or polymer cure initiator cationic initiator Generation of radicals in acrylate filler silica (Fumed silica) spacer polymer bead getter CaO Powder Nano-scale, Metal Oxide available (MgO ZrO ₂ , TiO ₂ , Al ₂ O ₃ , etc.)

In Table 4, the acrylate-based compound, the urethane diacrylate-based compound, the butadiene urethane diacrylate-based compound, and the curing initiator may be the same as or similar to those described with reference to Tables 1 and 3, so repeated descriptions thereof are excluded. do. In addition, since the fillers and spacers in Table 4 may be the same as or similar to those described with reference to Table 2, a repeated description thereof is excluded.

In the examples described with reference to Tables 3 and 4, the urethane diacrylate-based compound may further include a butadiene group, wherein the urethane diacrylate-based compound including the butadiene group is as described above. It can be expressed as Formula 7 or Formula 8.

A dam structure can be formed using the dam material composition for an image display device described above. The formation process of such a dam structure may follow an existing process. For example, UV curing, thermal curing, or a curing process using both UV and heat may be used. The dam structure formed from the dam material composition according to the embodiment may have excellent adhesion and oxygen/moisture barrier properties, as well as transparent properties (or substantially transparent properties). In addition, the dam structure formed from the dam material composition according to the embodiment may have flexible characteristics and may be applicable to various flexible/bendable/foldable display devices. In addition, a dam structure formed from the dam material composition according to the embodiment may have excellent reliability and durability. Therefore, by using the dam material composition according to the embodiment, an image display device having excellent reliability and durability can be manufactured. In particular, the dam material composition according to the embodiment can be usefully applied to the manufacture of deformable image display devices such as flexible/bendable/foldable.

2 is a cross-sectional view exemplarily showing an image display device to which a dam structure formed from a dam material composition according to an embodiment of the present invention is applied.

Referring to FIG. 2 , an image display device according to an embodiment includes a display element substrate 100, an encapsulation layer member 300 disposed on the display element substrate 100, and a display element substrate 100. A dam structure 200 provided for sealing between the sealing layer members 300 may be included.

The display element substrate 100 may include a substrate part 100a and a display element part 100b disposed on the substrate part 100a. The substrate portion 100a may include, for example, a thin film transistor (TFT) array, and the display device portion 100b may include, for example, an OLED device portion. The dam structure 200 may be provided on an area of the substrate portion 100a outside the display device portion 100b. The dam structure 200 may be formed from a dam material composition according to embodiments of the present invention.

The display device substrate 100 and the encapsulation layer member 300 may have flexible characteristics. In this case, the image display device may be a flexible, bendable or foldable device. However, in some cases, at least a portion of the display element substrate 100 and the encapsulation layer member 300 may be non-flexible and rigid members. That is, the image display device may be a rigid device.

An image display device to which a dam structure formed from a dam material composition according to an embodiment has been described with reference to FIG. 2 , but this is only exemplary, and the configuration of the image display device may be variously changed. The dam structure according to the embodiment of the present invention can be applied to various image display devices to which the existing dam structure is applied.

1. Production example (production of dam material composition)

[Diurethane dimethacrylate, mixture of isomers (CAS No. 72869-86-4 /Sigma Aldrich)]

[Polyurethane diacrylate]

[Polybutadiene urethane acrylate]

[Polyester acrylate]

A dam material composition was prepared with the materials and contents (wt%) shown in Table 5 below.

The manufacturing method is as follows. ⅰ) After adding resin (polymer, oligomer, or monomer) and an initiator, they are stirred at a speed of 1,000 rpm or more, respectively, using a mixer using revolution-rotation. Stirring time is 10 min or more. ii) Add a getter and stir at the same speed, and the minimum stirring time is 20 min or more. When frictional heat is generated due to high viscosity, cool the heat in the middle while stirring. iii) Add filler and spacer and stir under the same conditions as resin.

However, in addition to the aforementioned revolution-rotation stirring method, it may be produced using a Planetary Disper mixer or a Roll-Mill mixer. In addition, in order to improve the dispersibility of the getter, it is okay to prepare by mixing the resin and the getter in advance.

division Resin A Resin B Initiator A
1-Hydroxycyclohexyl Phenyl Ketone Initiator B
Bis(4-dodecylphenyl)
iodonium hexaflurorantimonate Fumed Silica PMMA beads CaO Nanopowder Example 1 2-hydroxyethyl methacrylate
10% [Formula 9]
66.5% 3% - 5% 0.5% 15% Example 2 [Formula 10]
(molecular weight: 3,000)
66.5% - 5% Example 3 [Formula 10] (molecular weight: 7,500)
68.5% - 3% Example 4 [Formula 10]
(molecular weight: 25,000)
69.5% - 2% Example 5 [Formula 10] (molecular weight: 70,000)
70.5% - One% Example 6 [Formula 11] (molecular weight: 25,000)
69.5% - 2% Example 7 3-4-epoxycyclohexylmethyl-3-4-epoxycyclohexanecarboxylate
40% [Formula 10]
(molecular weight: 25,000)
37.5% 1.5% 1.5% 4% Example 8 3-4-epoxycyclohexylmethyl-3-4-epoxycyclohexanecarboxylate 65% [Formula 10]
(molecular weight: 25,000)
12.5%
2.4% 0.6% 4% Example 9 2-hydroxyethyl methacrylate 10% [Formula 10]
(molecular weight: 25,000)
55.60%
[Formula 11]
(molecular weight: 23,900)
13.90% 3% - 2% Comparative Example 1 3-4-epoxycyclohexylmethyl-3-4-epoxycyclohexanecarboxylate 73% [Formula 10]
(molecular weight: 25,000)
5.0% 2.3% 0.2% 4% Comparative Example 2 2-hydroxyethyl methacrylate 10% [Formula 12]
(molecular weight: 25,000)
69.5% 3% - 2% Comparative Example 3 2-hydroxyethyl methacrylate 10% Novolac acrylate
(molecular weight: 25,000)
69.5% 3% - 2% Comparative Example 4 2-hydroxyethyl methacrylate
76.5% - 3% - 5% Reference example 1 2-hydroxyethyl methacrylate
5% [Formula 10]
(molecular weight: 25,000)
91% 1.5% - One% - 1.5%

All of the component contents in Table 5 mean % by weight.

division 2-hydroxyethyl methacrylate Resin B
[Formula 12]
(molecular weight 90,000) Initiator A
1-Hydroxycyclohexyl Phenyl Ketone Fumed Silica PMMA beads CaO Nanopowder Reference example 2 76.5 One 2.4 5.0 0.1 15 Reference example 3 74.5 3 Reference example 4 72.5 5 Reference Example 5 70.5 7 Example 10 67.5 10 Example 11 47.5 30 Example 12 27.5 50 Example 13 10 67.5 Example 14 5 72.5

All of the component contents in Table 6 mean % by weight.

2. Adhesion comparison test

The adhesion of the dam material compositions prepared according to Examples and Comparative Examples was measured in the following manner.

(1) 0.2 to 2 mg of a dam material composition (resin composite) is placed on a glass (lower glass) having a size of 2.5 x 4 cm ² and a thickness of 0.5 cm, and a glass of the same shape is placed thereon Rotate (upper glass) by 90° and raise it.

(2) A weight of 500 g is placed on the upper glass and pressed for about 15 to 30 seconds so that the size of the dot by the dam material composition is about 5 mm.

(3) The dam material composition is exposed to light at an intensity of about 3000 to 3300 mJ using a UV exposure machine, and after exposure, curing is performed at about 100° C. for 30 minutes using a hot plate.

(4) The adhesion is measured using a universal testing machine (UTM).

(5) Adhesion is measured according to the elapsed time while storing the dam material composition in an oven at 85° C. and 85 RH% relative humidity.

Table 7 below summarizes the results of measuring the change in adhesion (adhesion strength) over time of the dam material compositions according to the examples and the dam material compositions according to the comparative examples. In Table 7, the unit of adhesion (adhesion strength) is kgf/cm ² .

division adhesion
(kgf/cm ² ) Attachment reliability (kgf/cm ² ) 0 hours 100 hours 300 hours 500 hours Example 1 2.85 2.93 2.76 2.56 2.30 Example 2 3.52 3.52 3.00 2.60 2.51 Example 3 3.87 3.87 3.56 3.37 3.20 Example 4 4.22 4.22 4.17 4.00 3.89 Example 5 4.02 4.02 4.12 3.65 3.32 Example 6 2.56 2.56 2.62 2.33 2.17 Example 7 2.66 2.66 2.69 2.25 2.02 Example 8 2.05 2.05 2.00 1.85 1.75 Example 9 3.07 3.15 2.97 3.09 2.89 Comparative Example 1 1.27 1.27 1.00 1.02 0.85 Comparative Example 2 1.46 1.46 1.02 0.79 0.55 Comparative Example 3 1.75 1.75 1.04 0.82 0.62 Comparative Example 4 1.02 1.02 0.24 0.32 0.22 Reference example 1 4.22 3.75 3.60 3.42 3.07

Referring to Table 7, the dam material compositions according to the embodiments may have high adhesion (adhesion strength) of 2.0 or more, and excellent adhesion may be well maintained even after a long time has elapsed. On the other hand, the dam material compositions according to Comparative Examples showed relatively low adhesive strength, and a significant deterioration phenomenon in which the adhesive strength decreased over time. In addition, when urethane diacrylate and butadiene urethane diacrylate are simultaneously used, adhesion reliability can be further improved. Since butadiene has high resistance to moisture, the initial adhesion can be maintained until the end of the evaluation under conditions of high temperature and high humidity.

division adhesion
(kgf/cm ² ) Reference example 2 1.51 Reference example 3 1.69 Reference example 4 1.80 Reference Example 5 1.96 Example 10 2.56 Example 12 4.02 Example 12 4.55 Example 13 4.99 Example 14 7.21

Referring to Table 8, Reference Examples 2 to 5 and Examples 10 to 14 are experimental groups to find out the appropriate content for the expression of the adhesion effect of polyurethane diacrylate, and through the above results, polyurethane diacryl It can be said that it is advantageous to develop adhesive force when the rate is included at 10% by weight or more.

In this specification, preferred embodiments of the present invention have been disclosed, and although specific terms have been used, they are only used in a general sense to easily explain the technical details of the present invention and help understanding of the present invention, and do not limit the scope of the present invention. It is not meant to be limiting. It is obvious to those skilled in the art that other modifications based on the technical idea of the present invention can be implemented in addition to the embodiments disclosed herein. For example, for those skilled in the art, a dam material composition for an image display device according to the embodiment described with reference to FIGS. 1 and 2 and Tables 1 to 8, a dam structure formed therefrom, and a dam structure It will be appreciated that the image display device including may be variously modified. In addition, it will be appreciated that the dam structure according to the embodiment can be applied not only to flexible display devices but also to rigid display devices. Therefore, the scope of the invention should not be determined by the described embodiments, but by the technical idea described in the claims.

* Description of symbols for main parts of drawings *
10: acrylate-based compound 20: urethane diacrylate-based compound
30: curing initiator 100: display element substrate
100a: substrate part 100b: display element part
200: dam structure 300: sealing layer member

Claims (20)

An acrylate-based compound having a form of at least one of a monomer and an oligomer;
A urethane diacrylate-based compound having a repeating unit containing a urethane group;
curing initiators; and
Including; getter;
Dam material composition for image display devices. According to claim 1,
The dam material composition for the image display device,
7 to 80% by weight of the acrylate-based compound;
7 to 90% by weight of the urethane diacrylate-based compound;
0.05 to 5% by weight of the curing initiator; and
A dam material composition for an image display device comprising 0.1 to 40% by weight of the getter. According to claim 1,
The repeating unit provided by the urethane diacrylate-based compound further comprises a chain-like hydrocarbon structure having 2 or more carbon atoms. According to claim 1,
The dam material composition for an image display device wherein the repeating unit provided by the urethane diacrylate-based compound further comprises a cycloalkyl group. According to claim 1,
The urethane diacrylate-based compound is a dam material composition for an image display device represented by Formula 1 below.
[Formula 1]

(A and A` independently include an acrylate group or a methacrylate group, R includes a chain hydrocarbon structure having 1 or more carbon atoms, R′ includes a cycloalkyl group, and m is 1 ~ 50,000) According to claim 5,
The A and the R are connected by a urethane bond,
The A' and the R' are connected by a urethane bond,
Wherein R is -O-CH ₂ -(CH ₂ ) _n -CH ₂ -A dam material composition for an image display device comprising a group. According to claim 1,
At least a portion of the urethane diacrylate-based compound is a dam material composition for an image display device represented by Formula 2 below.
[Formula 2]

(The R _A includes a hydroxyalkyl acrylate, the R _I includes an alicyclic structure or a cyclic alicyclic structure, the R _P includes an alkyl or unsaturated alkyl structure, and the m is 1 to 50,000 am) According to claim 7,
R _A includes any one selected from the group consisting of hydroxyethyl acrylate, hydroxyethyl methacrylate and hydroxypropyl acrylate, and R _I is toluene, diphenylmethane, tetramethylene, xylene, includes any one selected from the group consisting of isophorone, dicyclohexylmethane and hexamethylene, and R _P includes any one selected from the group consisting of polyether, polyester, polycaprolactone, polycarbonate and alkyl polyol Dam material composition for an image display device to be. According to claim 1,
The urethane diacrylate-based compound is a dam material composition for an image display device having a form of at least one of an oligomer and a polymer. According to claim 1,
The urethane diacrylate-based compound is a dam material composition for an image display device having a weight average molecular weight of 300 to 300,000. According to claim 1,
The acrylate-based compound is a dam material composition for an image display device comprising at least one of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, isobornyl acrylate and vinyl acrylate. According to claim 1,
The urethane diacrylate-based compound is a dam material composition for an image display device containing a butadiene group. According to claim 1,
The dam material composition is a dam material composition for an image display device further comprising a butadiene urethane diacrylate-based compound. According to claim 13,
The content of the butadiene urethane diacrylate-based compound is 5 to 20% by weight of the total content of the urethane diacrylate-based compound Dam material composition for an image display device. According to claim 1,
The dam material composition further comprises at least one of a filler, a spacer, and an additive. According to claim 1,
The viscosity of the dam material composition is 70,000 to 350,000 cP dam material composition for an image display device. According to claim 1,
The dam material composition is a dam material composition for an image display device having an adhesive strength of 2.0 kgf / cm ² or more. According to claim 1,
The dam material composition includes an epoxy-based compound,
Dam material composition for an image display device further comprising a curing agent of the epoxy-based compound. According to claim 1,
The getter is a dam material composition for an image display device comprising a metal oxide or an organic getter capable of absorbing moisture. a display element substrate;
an encapsulation layer member disposed on the display element substrate; and
An image display device comprising a dam structure formed from the dam material composition according to any one of claims 1 to 19, provided for sealing between the display element substrate and the encapsulation layer member.

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