HK1191965B

HK1191965B - Epoxy polymerizable composition and organic el device

Info

Publication number: HK1191965B
Application number: HK14105308.0A
Authority: HK
Inventors: 山本佑五; 高木正利; 藤井俊介; 前川真太朗; 大池节子
Original assignee: 三井化学株式会社
Priority date: 2011-07-06
Filing date: 2012-07-05
Publication date: 2016-11-18

Description

Epoxy polymerizable composition and organic EL device

Technical Field

The present invention relates to an epoxy polymerizable composition and an organic EL device.

Background

Organic EL devices are expected as next-generation displays and lighting devices because they consume less power and have low viewing angle dependence. However, the organic EL element has a problem that it is easily deteriorated by moisture or oxygen in the atmosphere. Therefore, the organic EL element is sealed with a sealing member and used.

A method of sealing the organic EL element includes a method called "frame sealing" and a method called "surface sealing". The frame sealing means a method of: in a structure in which a sealing cover is disposed on an organic EL element disposed on a substrate, the peripheral edge of the sealing cover is sealed with a sealing member (see patent document 1 and the like). The surface sealing is a method of sealing the organic EL element so as to cover the organic EL element. As an example thereof, the following method can be cited: in a structure in which a sealing plate is disposed on an organic EL element disposed on a substrate, a sealing material is filled in a space between the sealing plate and the substrate and between the organic EL element and the sealing plate to seal the structure (see patent document 2 and the like).

The surface sealing is considered effective when the panel size of the organic EL is large or when light is extracted by a so-called top emission method. In the case of the top emission type, the sealing member for surface sealing is disposed at any position of a space formed between the organic EL element and the sealing plate. Therefore, the refractive index of the sealing member needs to be high (the difference between the refractive index of the sealing member and that of the transparent electrode is small). The reason for this is that: if the refractive index of the sealing member is low, total reflection occurs between the electrode and the sealing member, and the efficiency of extracting light from the organic EL element decreases.

When surface sealing is performed by screen printing, dispensing, or the like, the sealant composition is required to be liquid at a temperature near room temperature. If the sealant composition is not in a liquid state at a temperature around room temperature, the workability is poor, and when sealing an organic EL element, the sealant composition needs to be heated and melted. If heating is performed, thermal strain of the display member is generated, and therefore sealing may not be performed sufficiently. In addition, if the sealant composition is heated, a curing reaction proceeds and the viscosity tends to become unstable.

As an adhesive composition suitable for bonding of optical members, a photocurable adhesive composition containing a thiol compound and an epoxy compound has been proposed (see patent document 3 and the like). Since the photocurable adhesive composition contains a large amount of sulfur element, it is considered that a cured product thereof has a high refractive index. Further, the photocurable adhesive composition has a low softening point and excellent workability at room temperature because it does not have a rigid molecular structure such as a fluorene skeleton, but has a problem of low heat resistance.

A photocurable adhesive comprising an epoxy compound containing a sulfur atom and (meth) acrylic acid; it is considered that it has high adhesion and high refractive index and is excellent in heat resistance (see patent document 4). In addition, there are known a curable resin composition containing an epoxy oligomer containing a sulfur atom and a compound copolymerizable therewith; it is considered that a cured product thereof has a high refractive index (see patent document 5).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 11-45778

Patent document 2: japanese patent laid-open publication No. 2001-357973

Patent document 3: japanese patent laid-open publication No. 2004-35857

Patent document 4: japanese laid-open patent publication No. 10-324858

Patent document 5: japanese laid-open patent publication No. 8-183816

Disclosure of Invention

Problems to be solved by the invention

If the refractive index of the surface sealing material of the organic EL element is increased, the light extraction efficiency of the organic EL device is improved. In order to increase the refractive index of the surface sealing material, the electron density of the cured resin constituting the surface sealing material may be increased. In order to increase the electron density of the resin cured product, a part of the polymerizable component of the resin polymerizable composition may be a sulfur-containing compound such as a thiol-containing compound.

In addition, moldability is required for a polymerizable resin composition for electronic materials. For example, when surface sealing an organic EL element, a polymerizable resin composition is often applied to the organic EL element by a print application method such as screen printing. The printing coating is preferably a high-speed coating of the polymerizable resin composition by a high shearing force, and therefore, the viscosity of the polymerizable resin composition is preferably a certain value or less.

In order to reduce the viscosity of the polymerizable resin composition, for example, a solvent may be added. However, the organic solvent may deteriorate precision electronic components such as organic EL elements. For example, the organic solvent in the polymerizable resin composition may be volatilized as outgas when exposed to a heating environment, thereby deteriorating the precision electronic component. On the other hand, if a high-boiling organic solvent is contained in the polymerizable resin composition, the solvent remains in the cured product, and it is therefore difficult to impart desired characteristics (for example, refractive index) to the cured product.

In order to reduce the viscosity of the polymerizable resin composition, a part of the polymerizable component may be a low molecular weight component. However, since the low-molecular-weight component has low compatibility with other polymeric components, the transparency of the cured product may be reduced (cloudiness may occur). In addition, the viscosity of the polymerizable resin composition under high shear force is easily affected by the combination of the components contained therein, and therefore, it is necessary to select an appropriate component.

On the other hand, if the viscosity is too low, the printability may be degraded, for example, the outline may become unclear during printing. Accordingly, an object of the present invention is to provide a polymerizable resin composition having a cured product with a high refractive index and a viscosity under a high shear force of a predetermined value or less.

Means for solving the problems

The first aspect of the present invention relates to the following epoxy polymerizable composition, cured product thereof, and the like.

[1] An epoxy polymerizable composition comprising: (A1) a sulfur-containing epoxy compound represented by the following general formula (i) and having a refractive index of 1.66 to 1.80; (A2) an epoxy compound having a softening point of 70 ℃ or lower (except for the above-mentioned (A1) sulfur-containing epoxy compound); (B) a curing accelerator; and (C) 1a thiol compound having 2 or more thiol groups in the molecule; and has a viscosity of 100 to 15000 mPas at 25 ℃ and 60rpm as measured by a B-type viscometer.

General formula (i)

[ in the above-mentioned general formula (i),

A₁and A₂Each independently represents a benzene ring or a1, 3, 5-triazine ring,

X₁₁each independently represents-S-, -SO₂-、-O-、-C(R₁₁)₂-（R₁₁Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms),

Y₁₁and Y₁₂Each independently represents-O-or-S-,

Z₁and Z₂Each independently represents-O-or-S-,

R₁₁and R₁₂Each independently represents an alkyl group having 1 to 6 carbon atoms or a halogen group,

m_arepresents any integer of 0 to 10,

m_cin A₂When the ring is a benzene ring, it represents an integer of 1 to 5, wherein A is₂1 or 2 in the case of a1, 3, 5-triazine ring,

m_band n_aIn A₁Or A₂When the benzene ring is a benzene ring, each independently represents an integer of 0 to 4, wherein A represents₁Or A₂1,3, 5-triazine ring, each independently represents 0 or 1,

j and k are at A₁Or A₂When the benzene ring is a benzene ring, each independently represents an integer of 1 to 5, wherein A represents₁Or A₂1,3, 5-triazine ring, each independently represents 1 or 2,

m_bthe sum of j and A₁5 or less in the case of a benzene ring, in A₁2 or less in the case of a1, 3, 5-triazine ring,

n_aand k and m_cThe sum of which is A₂In the case of a benzene ring, 6 or less, in A₂3 or less in the case of a1, 3, 5-triazine ring,

when m is_aWhen 0, from Y₁₁、Y₁₂、Z₁And Z₂At least one of the groups represented is-S-,

when m is_a1-10 times, from X₁₁、Y₁₁、Y₁₂、Z₁And Z₂At least one of the groups represented is a group containing S.]

[2] The epoxy polymerizable composition according to [1], wherein the sulfur-containing epoxy compound represented by the general formula (i) is a sulfur-containing epoxy compound represented by the following general formula (1).

General formula (1)

[ in the above-mentioned general formula (1),

x represents-S-or-SO₂-，

Y₁And Y₂Each independently represents-O-or-S-,

m represents any integer of 0 to 10,

m1 and n each independently represent any integer of 0 to 4,

R₁and R₂Each independently represents an alkyl group having 1 to 6 carbon atoms or a halogen group,

when m is 0, Y₁And Y₂At least one of which is-S-]

[3] The epoxy polymerizable composition according to [1] or [2], further comprising (A3) a fluorene-based epoxy compound represented by the following general formula (2) or general formula (3).

General formula (2)

[ in the general formula (2),

R₁each independently represents a hydrogen atom or a methyl group;

R₂each independently represents a hydrogen atom or a methyl group;

R₃each independently represents an alkyl group having 1 to 5 carbon atoms;

R₄each independently represents an alkyl group having 1 to 5 carbon atoms;

m represents an integer of 2 or more;

n independently represents an integer of 0 to 3;

p independently represents an integer of 0 to 4;

q independently represents an integer of 0 to 5

General formula (3)

[ in the general formula (3),

y represents a single bond, an oxygen atom or a sulfur atom;

q independently represents an integer of 0 to 4;

R₁～R₄m, n and p are as defined for general formula (2)]

[4] The epoxy polymerizable composition according to any one of [1] to [3], wherein the epoxy compound (A2) is at least 1 epoxy compound selected from the group consisting of a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, an amino epoxy compound, and an epoxy compound represented by the following general formula (4).

General formula (4)

[ in the general formula (4),

R₁₂each independently represents an alkyl group having 1 to 5 carbon atoms or a halogen atom,

s is 0 to 4

[5] The epoxy polymerizable composition according to any one of [1] to [4], wherein the epoxy compound (A2) is a trifunctional epoxy compound.

[6] The epoxy polymerizable composition according to any one of [1] to [5], wherein the thiol equivalent weight of the thiol compound (C) is 80 to 100 g/eq; and the sulfur content of the thiol compound (C) is 50 to 80%.

[7] The epoxy polymerizable composition according to [6], wherein the molecular weight of the thiol compound (C) is 140 to 500.

[8] The epoxy polymerizable composition according to any one of [1] to [7], wherein the content of the (A1) sulfur-containing epoxy compound is 50 parts by mass or more per 100 parts by mass of the content of the epoxy compound contained in the epoxy polymerizable composition.

[9] The epoxy polymerizable composition according to any one of [1] to [8], wherein a molar ratio of the epoxy group to the thiol group contained in the epoxy polymerizable composition is 1: 0.9 to 1.1.

[10] The epoxy polymerizable composition according to any one of [1] to [9], wherein the water content is 0.1% by mass or less.

[11] A transparent resin for optical materials, which comprises the epoxy polymerizable composition according to any one of the above [1] to [10 ].

[12] An organic EL element surface sealing agent comprising the epoxy polymerizable composition according to any one of the above [1] to [10 ].

[13] A cured product of the epoxy polymerizable composition according to any one of the above [1] to [10], which has a refractive index of 1.68 or more.

A second aspect of the present invention relates to an organic EL device shown below, a method for manufacturing the same, and the like.

[14] An organic EL device which is an organic EL device, comprising: a display substrate on which an organic EL element is disposed; an opposing substrate which is paired with the display substrate; and a sealing member interposed between the display substrate and the counter substrate and filling a space formed between the organic EL element and the counter substrate; the sealing member is a cured product of the epoxy polymerizable composition according to any one of [1] to [10 ].

[15] An organic EL device, comprising: an organic EL element; a sealing member which is in contact with the organic EL element; and a passivation film in contact with the sealing member; the sealing member is a cured product of the epoxy polymerizable composition according to any one of [1] to [10 ].

[16] An organic EL display panel comprising the organic EL device according to [14] or [15 ].

[17] A method of manufacturing an organic EL device, comprising: a first step of forming an organic EL element on a display substrate; a2 nd step of sealing the organic EL element with the composition according to any one of [1] to [10 ]; a3 rd step of laminating an opposing substrate so as to oppose the display substrate with the composition interposed therebetween; and a 4 th step of curing the composition to form a sealing member.

[18] A method of manufacturing an organic EL device, comprising: a first step of forming an organic EL element on a substrate; a2 nd step of sealing the organic EL element with the composition according to any one of [1] to [10 ]; a3 rd step of curing the composition to form a sealing member; and a 4 th step of forming a passivation film on the sealing member.

ADVANTAGEOUS EFFECTS OF INVENTION

The epoxy polymerizable composition of the present invention can be molded into a cured product with good workability, and the refractive index of the cured product is high. Therefore, the epoxy polymerizable composition of the present invention is particularly suitable for forming a film of a surface sealing material for an optical device, particularly a light-emitting device.

Drawings

Fig. 1 is a diagram illustrating the structure of an organic EL device.

Fig. 2 is a diagram illustrating a manufacturing flow of the organic EL device.

FIG. 3 is a graph obtained by plotting the viscosity of the epoxy polymerizable composition obtained in examples and comparative examples and the refractive index of the cured product thereof.

Detailed Description

1. Epoxy polymerizable composition

The epoxy polymerizable composition of the present invention comprises (a1) a sulfur-containing epoxy compound, (a2) a low-softening-point epoxy compound having a low softening point (excluding a1), (B) a curing accelerator, and (C) a thiol compound. Further, (a3) a fluorene-based epoxy compound may be contained.

(A1) The sulfur-containing epoxy compound is represented by the following general formula (i). In the present specification, "epoxy group" also includes "thioepoxy group". In addition, the sulfur-containing epoxy compound (a1) also includes a thioepoxy compound having a thioepoxy group.

General formula (i)

In the above general formula (i), A₁And A₂Each independently represents a benzene ring or a1, 3, 5-triazine ring.

X₁₁Each independently represents-S-, -SO₂-、-O-、-C(R₂₁)₂-（R₂₁Each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms). When containing multiple X₁₁In the case of (2), each X₁₁May be the same or different.

R₁₁And R₁₂Each independently represents an alkyl group having 1 to 6 carbon atoms or a halogen group. The alkyl group having 1 to 6 carbon atoms may be a straight-chain or branched alkyl group; examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl and hexyl. Examples of halo groups include chloro, bromo, iodo, and the like.

m_bAnd n_aEach represents R₁₁And R₁₂The number of (a) is independently an integer of 0 to 4, preferably 0. If m is_bAnd n_aIf the amount is too large, the softening point of the sulfur-containing epoxy compound (A1) is lowered, and the workability of the epoxy polymerizable composition at the time of film formation is improved. On the other hand, the heat resistance and refractive index of a cured product of the epoxy polymerizable composition may be too low.

m_aRepresents an integer of 0 to 10, preferably 1.

m_cIn A₂When the benzene ring is a benzene ring, the number is an integer of 1 to 5. On the other hand, in A₂In the case of a1, 3, 5-triazine ring, 1 or 2 is represented. If m is_cWhen the number of (b) is large, the number of epoxy groups (including thioepoxy groups) in the compound of the general formula (i) increases, and the heat resistance of a cured product of the epoxy polymerizable composition improves.

Y₁₁And Y₁₂Each independently represents-O-or-S-. Z₁And Z₂Each independently represent-O-or-S-.

j and k are each independently an integer of 1 to 5. When j and k are large, the heat resistance of the cured product of the epoxy polymerizable composition is also improved, but the cure shrinkage rate may become too large.

Here, when m contained in the formula (i)_aWhen all are 0, from Y₁₁、Y₁₂、Z₁And Z₂At least one of the groups represented is-S-. On the other hand, when m contained in the formula (i)_aWhen any one of them is 1 to 10, from X₁₁、Y₁₁、Y₁₂、Z₁And Z₂At least one of the groups represented comprises S; i.e. Y₁₁、Y₁₂、Z₁And Z₂At least one of them is-S-or X₁₁is-S-or-SO₂-. That is, the compound represented by the above general formula (i) necessarily contains an S atom.

In addition, n_aAnd k and m_cThe sum of which is A₂In the case of a benzene ring, 6 or less, in A₂In the case of a1, 3, 5-triazine ring, the number is 3 or less. Further, in the general formula (i), m in the phenyl group to which the group represented by the following formula is bonded_bThe sum of j and j is 5 or less.

The compound represented by the general formula (i) has a refractive index of 1.66 to 1.80. When the refractive index of the sulfur-containing epoxy compound (A1) represented by the general formula (i) is 1.66 or more, the refractive index of the cured product of the epoxy polymerizable composition is increased. The refractive index refers to a value measured by a sodium D line (589 nm). The refractive index can be measured by a known method, but can be measured by a critical angle method using an abbe refractometer.

Examples of the sulfur-containing epoxy compound represented by the general formula (i) include compounds represented by the following general formulae (ii) to (iv).

General formula (ii)

General formula (iii)

In the general formula (iii), R₁₁、R₁₂、X₁₁、Y₁₁、Y₁₂、Z₁、Z₂、m_b、n_aJ and k are the same as in the above general formula (i).

General formula (i)_v）

In the general formula (iv), R₁₁、R₁₂、X₁₁、Y₁₁、Y₁₂、Z₁、Z₂、m_b、n_aJ and k are the same as in the above general formula (i).

Particularly preferable examples of the sulfur-containing epoxy compound represented by the general formula (i) include a sulfur-containing epoxy compound represented by the following general formula (1).

General formula (1)

In the above general formula (1), X represents-S-or-SO₂-。Y₁And Y₂Each independently represents-O-or-S-. m represents an integer of 0 to 10, preferably 1. When m is 0, Y₁And Y₂At least one of (a) is-S-. That is, the compound represented by the above general formula (1) necessarily contains an S atom.

R₁And R₂Each independently represents an alkyl group having 1 to 6 carbon atoms or a halogen group. The alkyl group having 1 to 6 carbon atoms may be a straight-chain or branched alkyl group; examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl and hexyl. Examples of halo groups include chloro, bromo, iodo, and the like. m1 and n each independently represent any integer of 0 to 4, preferably 0.

Specific examples of the sulfur-containing epoxy compound represented by the general formula (1) include: bis [4- (2, 3-epoxypropylthio) phenyl ] sulfide, bis [4- (2, 3-epoxypropylthio) -3-methylphenyl ] sulfide, bis [4- (2, 3-epoxypropylthio) -3, 5-dimethylphenyl ] sulfide, bis [4- (2, 3-epoxypropylthio) -2,3,5, 6-tetramethylphenyl ] sulfide, bis [4- (2, 3-epoxypropylthio) -3-hexylphenyl ] sulfide, bis [4- (2, 3-epoxypropylthio) -3, 5-dihexylphenyl ] sulfide, bis [4- (2, 3-epoxypropylthio) -3-chlorophenyl ] sulfide, bis [4- (2, 3-epoxypropylthio) -3, 5-dichlorophenyl sulfide, bis [4- (2, 3-epoxypropylthio) -2,3,5, 6-tetrachlorophenyl ] sulfide, bis [4- (2, 3-epoxypropylthio) -3-bromophenyl ] sulfide, bis [4- (2, 3-epoxypropylthio) -3, 5-dibromophenyl ] sulfide, bis [4- (2, 3-epoxypropylthio) -2,3,5, 6-tetrabromophenyl ] sulfide, and the like.

Preferred specific examples of the sulfur-containing epoxy compound represented by the general formula (1) include: bis [4- (2, 3-epoxypropylthio) phenyl ] sulfide, bis [4- (2, 3-epoxypropylthio) -3-methylphenyl ] sulfide, bis [4- (2, 3-epoxypropylthio) -3, 5-dimethylphenyl ] sulfide, bis [4- (2, 3-epoxypropylthio) -3, 5-dibromophenyl ] sulfide, and the like.

The method for producing the sulfur-containing epoxy compound (a1) is not particularly limited. For example, the sulfur-containing epoxy compound represented by the above general formula (ii) can be obtained by reacting a trithiol compound of the following formula with an epihalohydrin.

The sulfur-containing epoxy compound represented by the general formula (1) can be prepared, for example, by reacting the following formula (X, Y)₁、Y₂、m、R₁、R₂M1 and n are each as defined in general formula (1) with an epihalohydrin.

(A1) The sulfur-containing epoxy compound easily increases the refractive index of a cured product of the epoxy polymerizable composition. Further, since it is not a compound having an excessively high viscosity, the viscosity of the epoxy polymerizable composition is not increased more than necessary. Further, the epoxy resin composition is also excellent in compatibility with a low softening point epoxy compound (A2) described later.

The epoxy polymerizable composition of the present application has a low viscosity even when a high shear force is applied thereto. For example, in the (A1) sulfur-containing epoxy compound represented by the general formula (i), even m_cAnd m_aIs 1 or more, X₁₁Also relatively short, crosslinked portions, Y₁₁And Y₁₂Also short cross-linked. Thus, ring A₁Ring A₂And the conformation of the epoxy group (thioepoxy group) is low in degree of freedom, and the sulfur-containing epoxy compound (a1) is likely to become a compact structure. In addition, due to the ring A₁Ring A₂Since the sulfur-containing epoxy compound (A1) has a relatively small ring size such as a benzene ring or a1, 3, 5-triazine ring, the volume of the sulfur-containing epoxy compound is small. Therefore, it is considered that the viscosity of the epoxy polymerizable composition can be kept low even when a high shear force is applied to the composition. Furthermore, 1 has at least a certain number of rings A in the molecule₁Ring A₂Thus, the low softening point epoxidation reaction with (A2) described laterThe compound (particularly, the compound having a benzene ring) and the (A3) fluorene-based epoxy compound have high compatibility, and the cured product of the epoxy polymerizable composition has high transparency.

(A2) The low-softening-point epoxy compound preferably has a softening point of 70 ℃ or lower and can be in a liquid state at room temperature. The (A2) low softening point epoxy compound described in the specification of the present application does not contain (A1) a sulfur-containing epoxy compound. (A2) The epoxy compound having a low softening point can further improve the workability of the epoxy polymerizable composition. Further, the composition of the present invention has excellent compatibility with the above-mentioned components such as the sulfur-containing epoxy compound (a1), and also has an effect of preventing the occurrence of white turbidity in a cured product of the composition of the present invention. The softening point is determined by the ring and ball method (in accordance with JISK 7234).

(A2) The low softening point epoxy compound is not particularly limited, and includes bisphenol a type epoxy compounds, bisphenol F type epoxy compounds, amino epoxy compounds, epoxy compounds represented by the following general formula (4), and the like.

The bisphenol a type epoxy compound and the bisphenol F type epoxy compound are represented by the following formulae, respectively. In the formula₁₀Each independently represents an alkyl group having 1 to 5 carbon atoms, preferably a methyl group; wherein p represents a substituent R₁₀The number of substitution (2) is 0 to 4, preferably 0.

Bisphenol A type epoxy compound

Bisphenol F-type epoxy compound

Typical examples of the amino epoxy compound are, for example, aniline type epoxy compounds shown below, and examples of the aniline type epoxy compounds include the following compounds. In the formula₁₁Represents an alkyl group having 1 to 5 carbon atoms or a halogen atom, q is 0 to 5, and r is 0 to 4.

Aniline epoxy compound

R in the general formula (4)₁₂Each independently represents an alkyl group having 1 to 5 carbon atoms or a halogen atom, and s is 0 to 4.

General formula (4)

It is preferable that at least a part of the (A2) epoxy compound having a low softening point is a trifunctional epoxy compound. When the epoxy resin is a trifunctional epoxy compound, the degree of crosslinking of a cured product of the epoxy polymerizable composition can be increased, and the heat resistance of the cured product can be improved.

(A3) The fluorene-based epoxy compound can increase the refractive index of a cured product of a polymerizable resin composition containing the fluorene-based epoxy compound. Further, since fluorene is a rigid aromatic group, the glass transition temperature Tg of a cured product of an epoxy polymerizable composition containing a fluorene-type epoxy compound is increased, and the heat resistance of the cured product is increased.

(A3) The softening point of the fluorene-based epoxy compound is preferably 50 to 200 ℃, more preferably 80 to 160 ℃. This is to improve the workability of the composition of the present invention and to improve the heat resistance of the cured product. Further, by including the component (a3), plasma resistance and weather resistance can be improved.

The fluorene-based epoxy compound is represented by general formula (2) or general formula (3).

General formula (2)

R in the general formula (2)₁Each independently represents a hydrogen atom or a methyl group, and is preferably a hydrogen atom for improving the reactivity of an epoxy group. R in the general formula (2)₂Each independently is a hydrogen atom or a methyl group, R₂Hydrogen atoms are preferred because: the reactivity of the epoxy group is excellent.

N in the general formula (2) represents the number of repeating alkylene ether units. n is an integer of 0 to 3. The larger n is, the lower the softening point of the compound is, and therefore, the workability in the production of a resin composition is improved as described later. However, if n is too large, the heat resistance of the cured product may be lowered. Therefore, n is preferably 0 or 1.

M in the general formula (2) represents the number of substitution of the substituent containing an epoxy group, and is an integer of 2 or more, and usually 4 or less. The "substituent containing an epoxy group" refers to a substituent containing an epoxy group bonded to a benzene ring. The substituent containing an epoxy group may be bonded to an arbitrary benzene ring. If m is large, the heat resistance of the cured product is excellent, but the cure shrinkage may become too high. Therefore, m is preferably 2.

P in the general formula (2) represents R₃The number of substitutions of (a) is an integer of 0 to 4. If p is large, the softening point is lowered and the workability is improved, but the heat resistance and the refractive index in the case of producing a cured product may be too low. Therefore, p is preferably 0 or 1, more preferably 0. R in the general formula (2)₃Each independently represents an alkyl group having 1 to 5 carbon atoms. If the carbon number is large, the softening point decreases and the workability improves, but the heat resistance and refractive index in the case of producing a cured product may be too low, so that R may be₃Preferably methyl.

Q in the general formula (2) represents R₄The number of substitutions of (a) is an integer of 0 to 5. When q is large, the softening point decreases and the workability improves, but the heat resistance and the refractive index may be changed when the cured product is obtainedToo low. Therefore, q is preferably 0 or 1, and more preferably 0. R in the general formula (2)₄Each independently represents an alkyl group having 1 to 5 carbon atoms. If the carbon number is large, the softening point decreases and the workability improves, but the heat resistance and refractive index in the case of producing a cured product may be too low, so that R may be₄Preferably methyl.

The fluorene-based epoxy compound represented by the above general formula (2) is preferably a compound represented by the following general formula (2-1).

General formula (2-1)

M in the general formula (2-1)_aEach independently represents an integer of 1 to 3, preferably 1. Q in the general formula (2-1) independently represents an integer of 0 to 4. R in the general formula (2-1)₁～R₄N and p are as defined for general formula (2).

General formula (3)

Y in the general formula (3) represents a single bond, an oxygen atom or a sulfur atom. Q in the general formula (3) independently represents an integer of 0 to 4. R in the general formula (3)₁～R₄M, n and p are defined as in the general formula (2).

The fluorene-based epoxy compound represented by the above general formula (3) is preferably a compound represented by the following general formula (3-1).

General formula (3-1)

M in the general formula (3-1)_bEach independently represents an integer of 1 to 3, preferably 1. Q in the general formula (3-1) independently represents an integer of 0 to 3. R in the general formula (3-1)₁～R₄N and p are as defined for general formula (3).

The compound represented by the general formula (3) has a rigid molecular structure compared with the molecular structure of the compound represented by the general formula (2). Therefore, the heat resistance of the cured product of the compound represented by the general formula (3) is increased. In particular, when Y is a single bond, the heat resistance of the cured product is significantly improved, but the softening point is too high, and the workability may be deteriorated. On the other hand, when Y is an oxygen atom or a sulfur atom, the balance of the above properties is excellent.

(A3) The fluorene-based epoxy compound can be obtained by, for example, reacting a phenol having a fluorene skeleton with epichlorohydrin (also referred to as "3-chloro-1, 2-epoxypropane") by a known method. By appropriately selecting the structures of epichlorohydrin and phenol having a fluorene skeleton, a desired epoxy compound can be synthesized. That is, R in the general formula (2) may be appropriately changed by using an epichlorohydrin derivative as a raw material instead of epichlorohydrin₁. For example, if an epichlorohydrin derivative having a methyl group substituted at the 2-position of 3-chloro-1, 2-epoxypropane is used as a raw material, R in the general formula (2) can be synthesized₁A fluorene-based epoxy compound which is a methyl group.

Phenols having a fluorene skeleton can be synthesized according to the method described in Japanese patent laid-open No. 2001-206862. When the skeleton of the phenol having a fluorene skeleton is selected, m and R in the general formula (2) can be appropriately changed₃And p. Further, when the polyfunctional hydroxyl group-containing fluorene compound described in patent document 3 is used as a raw material, R in the general formula (2) can be synthesized₂A fluorene-based epoxy compound which is a hydrogen atom or a methyl group and n is not 0.

As described above, the epoxy polymerizable composition of the present invention contains (a1) a sulfur-containing epoxy compound and (a2) a low softening point epoxy compound, and further contains (A3) a fluorene-based epoxy compound as a more preferable embodiment. When the total content of the sulfur-containing epoxy compound (a1) and the epoxy compound (a2) having a low softening point contained in the epoxy polymerizable composition is 100 parts by mass, or when the fluorene-based epoxy compound (A3) is contained, the content of the component (a1) is preferably 50 parts by mass or more when the total content of the component (a1), the component (a2) and the component (A3) is 100 parts by mass. In order to increase the refractive index of the cured product of the epoxy polymerizable composition, it is preferable to increase the content of the sulfur-containing epoxy compound (a 1). More specifically, if the content of the sulfur-containing epoxy compound (a1) is 50 parts by mass or more, the refractive index of the cured product can be easily adjusted to 1.68 or more.

When the composition of the present invention contains the fluorene-based epoxy compound (A3), the total content of the component (a1), the component (a2) and the component (A3) is preferably 1 to 60 parts by weight, more preferably 5 to 50 parts by weight or more, and still more preferably 10 to 30 parts by weight, based on 100 parts by weight of the composition. When the content of the fluorene-based epoxy compound (A3) is in the above range, the heat resistance, plasma resistance and weather resistance of the cured product of the epoxy polymerizable composition can be improved.

(B) Curing accelerator

Examples of the (B) curing accelerator which accelerates curing of the epoxy compound include imidazole compounds, amine compounds. Examples of the imidazole compound include 2-ethyl-4-methylimidazole and the like, and examples of the amine compound include tris-dimethylaminomethylphenol and the like. (B) The cure accelerator may also be a lewis base compound. When the epoxy polymerizable composition of the present invention is used as a sealing agent for a light-emitting device, particularly an organic EL device, (B) a curing accelerator is preferably a thermal curing accelerator, and the composition of the present invention preferably contains substantially no photo-curing accelerator. The reason for this is that: the light curing accelerator is decomposed at the time of accelerating curing, and gas or the like which deteriorates the light emitting element is often generated, as compared with the heat curing accelerator.

The content of the curing accelerator (B) in the epoxy polymerizable composition is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the total amount of the epoxy compounds. The reason for this is that: the epoxy polymerizable composition has an excellent balance between curability and storage stability.

(C) Thiol compounds

(C) The thiol compound is characterized by having 2 or more thiol groups in 1 molecule. (C) The thiol compound can be used as a curing agent for the epoxy compound. That is, the thiol group of the thiol compound (C) reacts with the epoxy group (including the thioepoxy group) of the epoxy compound, whereby these epoxy compounds are crosslinked with each other, and a cured product excellent in heat resistance, adhesive strength, and the like can be obtained. The thiol compound can also improve the transparency of a cured product of the epoxy polymerizable composition. The reason is presumed to be: (C) the thiol compound crosslinks the epoxy compound, thereby preventing the benzene ring or 1,3, 5-triazine ring in the epoxy compound from aggregating. From the viewpoint of improving the transparency of the cured product, the thiol compound (C) is preferably a compound having no benzene ring or 1,3, 5-triazine ring.

(C) The thiol compound is not particularly limited as long as it has 2 or more thiol groups in 1 molecule. If the number of thiol groups is large, the crosslinking density of the cured product of the obtained epoxy composition (hereinafter also simply referred to as "cured product") is increased, and therefore the heat resistance of the cured product is improved. However, if the number of thiol groups is too large, the thiol groups are present close to each other in the molecule of the thiol compound, and steric hindrance is likely to occur, and reactivity with an epoxy group (including a thioepoxy group) is reduced. The content of thiol groups in one molecule is represented by thiol equivalent (g/eq).

(C) The thiol equivalent of the thiol compound is 80 to 100g/eq, preferably 85 to 95g/eq, and more preferably 86 to 92 g/eq. The thiol equivalent is a value obtained by dividing the molecular weight of the thiol compound (C) by the number of thiol groups contained in the molecule. When the thiol equivalent is less than 80g/eq, the distance between the crosslinking points of the cured product becomes short, and therefore the reactivity with an epoxy group (including a thioepoxy group) may be lowered and the conversion rate may not be increased. On the other hand, if the thiol equivalent exceeds 100g/eq, the distance between the crosslinking points of the cured product becomes excessively long, and therefore the heat resistance of the cured product may decrease.

(C) The thiol compound may contain a sulfur atom other than a thiol group in its molecule. The thiol compound containing sulfur in the molecule increases the refractive index of the cured product of the epoxy polymerizable composition. Therefore, the sulfur content of the thiol compound (C) in the epoxy polymerizable composition is 50% to 80%, preferably 60% to 75%.

The sulfur content was determined from the ratio of each element (the ratio of sulfur element to all elements) obtained by mass analysis of the thiol compound. If the sulfur content is less than 50%, the refractive index of the cured product of the resin composition containing a thiol compound may not be sufficiently increased. In addition, since most of the thiol compounds having a sulfur content of more than 80% contain an S — S bond in the molecule, a cured product of a resin composition containing the thiol compounds may generate radicals or have poor chemical stability.

(C) The molecular weight of the thiol compound is preferably 140 to 500. If the molecular weight of the (C) thiol compound is high, the viscosity sometimes becomes too high or uniform curing does not proceed. The molecular weight can be determined by mass analysis.

(C) The thiol compound is not particularly limited as long as it has a thiol equivalent and a sulfur content within the above-described ranges. (C) Specific examples of the thiol compound include compounds represented by the following formulae (4), (5) and (6). The compounds represented by the formulae (4), (5) and (6) can be synthesized by a known method and are commercially available. The thiol equivalent of the compound of formula (4) was 87g/eq, and the sulfur content was 62%; the thiol equivalent of the compound of formula (5) was 91g/eq, and the sulfur content was 61%; the thiol equivalent of the compound of formula (6) was 89g/eq, and the sulfur content was 72%.

Formula (4)

Formula (5)

Formula (6)

The content of the thiol compound (C) in the epoxy polymerizable composition of the present invention is not particularly limited, and may be determined by the ratio of the molar amount of thiol groups and epoxy groups (including thioepoxy groups) contained in the epoxy polymerizable composition. The reason for this is that: (C) the thiol compound functions as a curing agent for the epoxy compound. If the epoxy polymerizable composition contains an excessive amount of thiol groups, thiol groups that have not reacted with epoxy groups (including thioepoxy groups) remain in the cured product. Therefore, there is a possibility that the member near the cured product is contaminated. On the other hand, if the thiol group is too small, the crosslinking density may not be sufficiently increased, and the heat resistance of the obtained cured product may be lowered.

For example, when the epoxy group (including the thioepoxy group) contained in the epoxy polymerizable composition of the present invention is 1 mole, the epoxy polymerizable composition preferably contains 0.9 to 1.1 moles of a thiol group, more preferably 0.95 to 1.05 moles of a thiol group, and particularly preferably 1 mole of a thiol group.

(D) Silane coupling agent

The epoxy polymerizable composition may further contain (D) a silane coupling agent. The epoxy polymerizable composition containing (D) a silane coupling agent has high adhesion to a substrate or the like when the epoxy polymerizable composition is produced into a sealing material composition for organic EL. (D) Examples of the silane coupling agent include silane compounds having reactive groups such as epoxy groups, carboxyl groups, methacryloyl groups, isocyanate groups, and the like. Specific examples of the silane compound include: trimethoxysilylbenzoic acid, gamma-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, gamma-isocyanatopropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane, beta- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, etc. The silane coupling agent may be 1 kind alone or a combination of 2 or more kinds.

The content of the silane coupling agent (D) in the epoxy polymerizable composition is preferably 0.05 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and still more preferably 0.3 to 10 parts by mass, per 100 parts by mass of the epoxy polymerizable composition.

(E) Other optional ingredients

The epoxy polymerizable composition may further contain other resin components, fillers, modifiers, stabilizers and other optional components within a range not impairing the effects of the present invention. Examples of other resin components include: polyamide, polyamideimide, polyurethane, polybutadiene, polychloroprene, polyether, polyester, styrene-butadiene-styrene block copolymer, petroleum resin, xylene resin, ketone resin, cellulose resin, fluorine-based oligomer, silicon-based oligomer, polysulfide-based oligomer. They may contain 1 of them alone or in combination of plural kinds.

Examples of fillers include: glass beads, styrene polymer particles, methacrylate polymer particles, ethylene polymer particles, and propylene polymer particles. The filler may be a combination of a plurality of fillers. Examples of the modifier include: polymerization initiation assistant, anti-aging agent, leveling agent, wettability improver, surfactant, plasticizer and the like. They may be used in combination of a plurality. Examples of the stabilizer include: ultraviolet absorbent, antiseptic, and antibacterial agent. The modifier may also be a combination of a plurality.

However, when transparency is required for a cured product of the composition of the present invention, it is preferable that the composition contains substantially no component which undergoes phase separation from the epoxy compound and has a large difference in refractive index from the epoxy compound; specifically, the epoxy resin composition does not contain an inorganic filler, an organic filler, or the like having a refractive index difference of 0.1 or more from a cured product of the epoxy compound and a diameter of 0.1 μm or more.

The water content of the epoxy polymerizable composition of the present invention is preferably 0.1% by mass or less, and more preferably 0.06% by mass or less, particularly when the epoxy polymerizable composition is used as a sealant for a light-emitting element. Since the organic EL element itself and a circuit in which the light-emitting element is disposed are easily deteriorated by moisture, it is preferable to reduce the moisture content of the epoxy polymerizable composition as much as possible. The water content of the epoxy polymerizable composition can be determined as follows: about 0.1g of a sample was measured, heated to 150 ℃ using a Karl Fischer moisture meter, and the amount of moisture generated at that time was measured to obtain (solid gasification method).

The epoxy polymerizable composition of the present invention has a viscosity at 25 ℃ of preferably 100 to 15000 mPas, more preferably 100 to 10000 mPas, and still more preferably 100 to 6000 mPas, from the viewpoint of ease of application and the like. The viscosity of the composition at 25 ℃ was measured by a B-type viscometer (BL type manufactured by Toyobo industries) at a rotation speed of 60 rpm. By adjusting the viscosity measured at a high rotation speed (60 rpm) in this manner, the printing workability by screen printing or the like can be improved. The reason for this is that: screen printing is a printing method in which a resin composition as a coated material is subjected to a shearing force.

The epoxy polymerizable composition of the present invention is preferably small in curing shrinkage. The curing shrinkage is preferably 10% or less, more preferably 8% or less. The curing shrinkage can be determined by substituting the specific gravity of the composition before curing and the specific gravity of the cured product after curing into the following formula.

Cure shrinkage (%) = { (specific gravity of cured product-specific gravity of uncured composition)/specific gravity of cured product } × 100

It is important that the curing shrinkage of the sealant composition used for producing a sealing member for a surface seal is low. The reason for this is that: if the cure shrinkage rate is high, a fine gap is formed between the sealing member, which is a cured product, and the substrate or the like due to internal stress, the adhesive strength is reduced, and the moisture permeation resistance is further reduced.

The cured product of the epoxy polymerizable composition of the present invention has a high refractive index. The refractive index of the cured product is preferably more than 1.60, more preferably 1.64 or more, further preferably 1.66 or more, and particularly preferably 1.68 or more. The refractive index refers to a value measured by a sodium D line (589 nm). The refractive index can be measured by a known method, and can be usually measured by a critical angle method using an abbe refractometer.

The cured product of the epoxy polymerizable composition of the present invention is preferably transparent in the visible light region. Transparency can be evaluated by light transmittance using an ultraviolet/visible spectrophotometer. The light transmittance of the cured product of the present invention is preferably 30% or more, more preferably 50% or more, and further preferably 80% or more at 450 nm. The reason for this is that: when a sealing member of an optical device (including an organic EL element) is manufactured, its display is improved.

The measurement of the light transmittance of the epoxy polymerizable cured product can be performed by the following procedure.

1) The epoxy polymerizable cured product was applied to a substrate and dried, and then cured to obtain a cured product having a thickness of 100 μm.

2) The transmittance at a wavelength of 450nm of the obtained cured product was measured by an ultraviolet/visible spectrophotometer (MULTISPEC-1500 manufactured by Shimadzu corporation).

The epoxy polymerizable composition of the present invention can be used as a sealing member by curing. Further, the present invention is preferably applied to a sealing member or an optical material through which light from an optical device passes. Examples of optical devices include: organic EL panels, liquid crystal displays, LEDs, electronic paper, solar cells, CCDs, and the like. Examples of the optical material include: optical adhesives, optical films, holographic materials, photonic crystals, diffraction gratings, prisms, index profile lenses, optical fibers, optical waveguide films, and the like.

Further, the epoxy polymerizable composition of the present invention is preferably used as a sealant composition (or a transparent resin composition for optical materials) to be used as a sealing member of a light-emitting element (particularly, an organic EL element having a top emission structure). The reason for this is that: when the sealing member of the organic EL element of the top emission structure is made, the efficiency of extracting light emitted from the organic EL element is improved. That is, in the organic EL element having the top emission structure, a transparent cathode electrode layer such as ITO is disposed on the organic EL layer. Since the refractive index of ITO is about 1.8, if the refractive index of the sealing member disposed on the cathode electrode layer is too low, the extraction efficiency of light emitted from the organic EL element decreases.

The epoxy polymerizable composition of the present invention can be produced by any method as long as the effect of the present invention is not impaired. For example, a method for producing an epoxy polymerizable composition includes: a step 1 of mixing the respective epoxy compounds (including (A1) to (A3)) to prepare an epoxy mixture, and a step 2 of mixing the epoxy mixture with (C) a thiol compound at 30 ℃ or lower. The mixing includes a method of charging these components into a flask and stirring them, and a method of kneading them with a three-roll mill. It is preferable to mix (B) a curing accelerator and other optional components with the mixture obtained in step 2.

The step 1 may be carried out under heating. In order to make the epoxy component as uniform as possible, the heating temperature is set in accordance with the softening point of each epoxy component.

In the step 2, (C) a thiol compound is mixed with the epoxy mixture under non-heating conditions (30 ℃ or lower). This is because the progress of the curing reaction (gelation, etc.) between the epoxy mixture and the (C) thiol compound is suppressed. The curing accelerator (B) is preferably mixed at 30 ℃ or lower in the same manner.

2. About organic EL device

As described above, the epoxy polymerizable composition of the present invention is useful as a composition for producing a sealing member of an organic EL device. That is, the organic EL device of the present invention includes: the display device includes a display substrate on which an organic EL element is disposed, an opposing substrate which is paired with the display substrate, and a sealing member which is disposed at any position between the display substrate and the opposing substrate and seals the organic EL element.

A method of sealing the organic EL element so as to cover the organic EL element is called a surface sealing, and an example thereof is a method of sealing by filling a sealing member into a space formed between the organic EL element and the counter substrate. On the other hand, a method of sealing by disposing a sealing member on the peripheral edge portion of the opposing substrate is referred to as frame sealing. The epoxy polymerizable composition of the present invention is applicable to a sealing member for use in both surface sealing and frame sealing, but is preferably a sealing member for use in surface sealing, and more preferably a sealing member for use in surface sealing of an organic EL device having a top emission structure.

Fig. 1A is a cross-sectional view schematically showing a first example of a surface-sealed organic EL device. The organic EL device 20 shown in fig. 1A includes: a display substrate 22, an organic EL element 24, a sealing substrate 26, and a sealing member 28 for surface sealing. The organic EL element 24 includes: a pixel electrode 30, an organic EL layer 32, and a counter electrode 34. The sealing member 28 in fig. 1A is a cured product of the epoxy polymerizable composition. Although not shown in fig. 1A, the counter electrode 34 may be covered with a passivation film made of an inorganic compound such as silicon oxide or silicon nitride.

Fig. 1B is a sectional view schematically showing a second example of a surface-sealed organic EL device. The organic EL device 20' shown in fig. 1B includes: a display substrate 22, an organic EL element 24, a sealing substrate 26, and a sealing member 28 for surface sealing. The organic EL element 24 includes: a pixel electrode 30, an organic EL layer 32, and a counter electrode 34. The seal member 28 in fig. 1B has: a cured resin layer 28-1, a passivation layer 28-2 formed of an inorganic compound such as silicon oxide or silicon nitride, and an adhesive resin layer 28-3. The cured resin layer 28-1 in fig. 1B may be a cured product of the epoxy polymerizable composition.

The organic EL device can be manufactured by any method. For example, the organic EL device 20 shown in fig. 1A can be manufactured by a method including: the method for manufacturing the sealing member includes a step 1 of applying a sealing material composition to the display substrate 22 on which the organic EL element 24 is laminated, a step 2 of obtaining a laminate by superimposing the pair of sealing substrates 26 on the display substrate 22 on which the sealing material composition is applied, and a step 3 of curing the sealing material composition (the epoxy polymerizable composition) of the obtained laminate to form the sealing member 28. Each step may be performed according to a known method. Examples of the method of applying the sealer composition include a method using screen printing or a dispenser. The viscosity of the epoxy polymerizable composition of the present invention is adjusted to 100 to 15000 mPas, and thus the coating is easy. The curing step is preferably carried out at 25 to 100 ℃ for 0.1 to 2 hours.

Fig. 2 schematically shows a manufacturing process of the organic EL device 20' shown in fig. 1B. First, the display substrate 22 on which the organic EL element 24 is stacked is prepared (fig. 2A). The organic EL element includes a pixel electrode 30, an organic EL layer 32, and a counter electrode 34, and may further include other functional layers. Next, a sealant composition (the epoxy polymerizable composition described above) is applied to the organic EL element 24 stacked on the display substrate 22 (so as to cover the counter electrode 34), and then cured to form a cured material layer 28-1 (fig. 2B).

Next, a passivation layer 28-2 is formed on the cured material layer 28-1 (fig. 2C). The passivation layer (transparent inorganic compound layer) 28-2 is formed by an arbitrary method, but may be formed by a plasma CVD method, a sputtering method, or the like. Further, the passivation layer 28-2 is covered with a resin layer (fig. 2D), the sealing substrate 26 is further stacked, the resin layer is cured in this state to form an adhesive resin layer 28-3, and the sealing substrate 26 is bonded (fig. 2E). Thus, the organic EL device 20' of the present invention was obtained.

The cured product of the epoxy resin composition of the present invention is less likely to have a reduced transparency even when exposed to plasma. Therefore, if the cured product layer 28-1 is a cured product of the epoxy polymerizable composition of the present invention, when the passivation layer 28-2 is formed by a plasma CVD method or the like, the transparency of the cured product layer 28-1 can be maintained even if the cured product layer 28-1 is exposed to plasma. Further, it is found that the organic EL device is often used in a form exposed to sunlight for a long time, and therefore weather resistance is also required for the cured product of the organic EL element surface sealing material, and the cured product of the epoxy resin composition of the present invention is excellent in weather resistance because transparency can be maintained even when exposed to plasma as described above.

Fig. 2 shows a flow of forming 1 organic EL element 24 on the display substrate 22 and sealing it; the plurality of organic EL elements 24 formed on the display substrate 22 can be sealed in 1 flow through the same steps.

The organic EL device of the present invention is applicable to an organic EL display panel. In general, in an organic EL display panel, organic EL devices are arranged in a matrix on a substrate.

Examples

The present invention will be described in more detail with reference to examples, but the scope of the present invention is not to be construed as being limited thereto.

An epoxy polymerizable composition was produced using the following components.

(A1) Sulfur-containing epoxy resin: TBBT epoxy compound (synthesized by the method described in Japanese unexamined patent publication No. H10-324858) having a refractive index of 1.68

(A2) Low softening point epoxy compound: EP3950S (manufactured by Adeka) aniline type trifunctional epoxy compound which is liquid at room temperature

(A2) Low softening point epoxy compound: VG3101 (manufactured by Printec corporation) has a softening point of 38 to 46 DEG C

(A2) Low softening point epoxy compound: YL983U bisphenol F type epoxy Compound (manufactured by Mitsubishi chemical Co., Ltd.), which is liquid at room temperature

(A3) Fluorene-based epoxy compound: PG-100 (Osaka gas Chemicals, Inc.)

(B) Curing accelerator: 2E4MZ (2-ethyl-4-methylimidazole)

(B) Curing accelerator: TMDPO (2, 4, 6-trimethylbenzoyldiphenylphosphine oxide)

(C) Thiol compounds: GST (Sanjing chemical Co., Ltd.)

(C) Thiol compounds: FSH (manufactured by Mitsui chemical Co., Ltd.)

(C) Thiol compounds: OPST (manufactured by Mitsui chemical Co., Ltd.)

(C) Thiol compounds: TBBT (4, 4' -thiobisbenzenethiol)

Acid anhydride: RikacidMH700 (manufactured by Nissi Sunbi chemical Co., Ltd.)

Acrylic acid: acrylic acid (manufactured by Tokyo chemical company)

[ example 1]

A flask was charged with 50 parts by mass of TBBT epoxy compound ((a 1) sulfur-containing epoxy compound), 20 parts by mass of EP3950S ((a 2) low softening point epoxy compound), and 30 parts by mass of PG-100 ((A3) fluorene-based epoxy compound), and mixed while heating. To this, 52 parts by mass of GST ((C) thiol compound) was added, and mixed at room temperature, and further 0.4 part by mass of 2E4MZ ((B) curing accelerator) was added, and stirred at room temperature to obtain an epoxy polymerizable composition.

[ examples 2 to 9]

As shown in table 1, epoxy polymerizable compositions were obtained by the same procedure as in example 1, except that the amount of the sulfur-containing epoxy compound (a1), the kind and amount of the low softening point epoxy compound (a2), the amount of the fluorene-based epoxy compound (A3), and the kind and amount of the thiol compound (C) were changed.

Comparative example 1

Epoxy polymerizable compositions having the compositions shown in table 2 were obtained by the same procedure as in example 1. An acid anhydride is blended in place of the thiol compound (C).

Comparative example 2

Epoxy polymerizable compositions having the compositions shown in table 2 were obtained by the same procedure as in example 1. The thiol compound (C) is not incorporated.

Comparative examples 3 to 4

Epoxy polymerizable compositions having the compositions shown in table 2 were obtained by the same procedure as in example 1. The sulfur-containing epoxy compound (A1) was not incorporated.

Comparative example 5

Epoxy polymerizable compositions having the compositions shown in table 2 were obtained by the same procedure as in example 1. The low softening point epoxy compound (A2) was not blended.

Comparative example 6

Epoxy polymerizable compositions having the compositions shown in table 2 were obtained by the same procedure as in example 1. The epoxy compound having a low softening point (A2) and the fluorene-based epoxy compound (A3) were not blended.

Comparative example 7

Epoxy polymerizable compositions having the compositions shown in table 2 were obtained by the same procedure as in example 1. Acrylic acid was added to the epoxy resin composition without adding (A2) a low softening point epoxy compound, (A3) a fluorene-based epoxy compound and (C) a thiol compound.

Comparative example 8

The epoxy polymerizable compositions obtained in examples 1 to 9 and comparative examples 1 to 8 were evaluated for the following items. The evaluation results are shown in tables 1 and 2.

[ State of the composition ]

The epoxy polymerizable composition was visually observed to confirm whether it was colorless and transparent.

[ viscosity of composition ]

The viscosity of the epoxy polymerizable composition at 25 ℃ was measured using a B-type VISCOMETER (BL-type VISCOMETER/rotor No4 manufactured by Toyobo industries Co., Ltd.) under a rotation condition of 60 rpm.

The epoxy polymerizable compositions obtained in examples 1 to 9 and comparative examples 1 to 6 were poured into a mold and heated at 90 ℃ for 1 hour to obtain a cured product having a thickness of 0.2 mm. Further, the epoxy polymerizable composition obtained in comparative example 7 was poured into a mold and irradiated with 10mW/cm²Further heated at 60 ℃ for 2 hours under UV light of (1) for 5 minutes to obtain a cured product having a thickness of 0.2 mm. The epoxy polymerizable composition obtained in comparative example 8 could not be cured.

[ State of cured product ]

The obtained cured product was visually observed to confirm whether it was colorless and transparent.

[ curing shrinkage ]

The curing shrinkage was determined by substituting the specific gravity of the composition before curing and the specific gravity of the cured product after curing into the following formula.

[ refractive index of cured product ]

The refractive index of the obtained cured product was measured by irradiating sodium D line (589 nm) with a refractometer (a multi-wavelength Abbe refractometer DR-M4 manufactured by Atago).

[ glass transition temperature of cured product ]

The linear expansion coefficient of the obtained cured product was measured using TMA (TMA/SS 6000 manufactured by Seiko instruments) at a temperature rise rate of 5 ℃/min, and the Tg was determined from the inflection point thereof.

[ haze value of cured product ]

The haze value (%) of the obtained cured product was measured using a haze meter (manufactured by Tokyo electrochromism, machine type name TC-H3 DPK). Thereafter, the cured product was set in a plasma treatment apparatus (manufactured by Yamatoscientific, machine type name PDC210, parallel plate type) and plasma treatment was performed for 20 minutes under conditions of an oxygen flow rate of 20mL/min and an RF output of 500W. The haze value (%) of the cured product layer after the plasma treatment was measured using a haze meter (manufactured by Tokyo electrochromism, machine type name TC-H3 DPK).

By performing the plasma treatment as described above to evaluate the change in haze, it was possible to evaluate whether or not the cured product of the surface sealant is an appropriate surface sealant in the production method of the organic EL device including the step of irradiating the cured product of the surface sealant with plasma, and also to perform accelerated evaluation of weather resistance.

[ Water content of composition ]

The water content of the epoxy polymerizable composition was measured by the Karl Fischer method, and as a result, the water content of the compositions of examples 1 to 9 and comparative examples 1 to 8 was 0.1 wt% or less.

[ Table 1]

[ Table 2]

Comparative examples 9 to 10

In a nitrogen-substituted flask, 100 parts by weight of an epoxy resin having a composition shown in table 3, 85 parts by weight of an acid anhydride, 4 parts by weight of a silane coupling agent, and 4 parts by weight of a curing accelerator shown in table 3 were stirred and mixed to obtain a surface sealing agent.

The viscosities of the surface sealants obtained in comparative examples 9 and 10 were measured. The viscosity of the epoxy polymerizable composition at 25 ℃ was measured using an E-type viscometer (DII-IIIULTRA, digital rheometer manufactured by BROOKFIEL). The measurement results are shown in table 1.

The curability of the surface sealants obtained in comparative examples 9 and 10 was evaluated by the following method. The samples were prepared by sandwiching each face sealant between 2 NaCl crystal plates (5 mm thick). The surface sealing agent was sealed between 2 NaCl crystal plates (2 cm square), and the gap between the NaCl crystal plates was set to 15 μm. The infrared transmission spectrum of the sample was measured by an FT-IR measuring apparatus before and after 30 minutes of heat treatment at 100 ℃. Absorption peak (910 cm) derived from expansion and contraction of antisymmetric ring of epoxy group based on the obtained spectrum^-1Near) height divided by the absorption peak (1600 cm) derived from intra-ring C-C stretching of the benzene ring^-1Nearby) height for normalization. Then, the reaction rate of the epoxy group was calculated from the degree of decrease of the peak derived from the epoxy group due to the heat treatment.

When the standard value of the epoxy group peak before heat treatment was x1 and the standard value of the epoxy group peak after heat treatment was x2, the value calculated by { (x 1-x 2)/x 1 }. times.100 (%) was calculated as the epoxy conversion. When the conversion of the epoxy resin was 80% or more, the evaluation was rated as ≈ o.

Preparation of the cured layer

The surface sealants (5 cm. times.5 cm. times.3 μm thick) obtained in comparative examples 9 and 10 were printed on a glass substrate (7 cm. times.7 cm. times.0.7 mm thick) cleaned in advance by ozone treatment using a screen printer (screen printer model 2200, manufactured by MITANI). The printed glass substrate was heated on a hot plate heated to 100 ℃ for 30 minutes to form a cured layer.

The haze value (%) of the cured product layer was measured using a haze meter (manufactured by Tokyo electrochromism, machine type name TC-H3 DPK). Thereafter, the glass substrate on which the cured product layer was formed was set in a plasma processing apparatus (PDC 210, a parallel plate type machine, manufactured by YamatoScientific) and plasma processing was performed for 20 minutes under conditions of an oxygen flow rate of 20mL/min and an RF output of 500W. Then, the haze value (%) of the cured product layer after the plasma treatment was measured using a haze meter (manufactured by tokyo electric color, machine type name TC-H3 DPK). The haze measurements are shown in table 1.

[ Table 3]

YL-983U: bisphenol F type epoxy resins (manufactured by japan epoxy resin corporation); VG-3101L: trifunctional epoxy resin: molecular weight 592 (manufactured by Printec corporation); MH-700: a mixture of methylhexahydrophthalic anhydride and hexahydrophthalic anhydride (manufactured by Nissan chemical Co., Ltd.); KBM-403: 3-glycidoxypropyltrimethoxysilane, molecular weight 236 (manufactured by shin-Etsu chemical); 2E4 MZ: 2-phenyl-4-methylimidazole (Curezol 2P4MZ, manufactured by four kingdoms); SA-810: diazacycloundecene phthalate (manufactured by San-Apro)

The epoxy polymerizable compositions obtained in the examples were colorless and transparent, and the viscosity thereof was suppressed to be low (14000 mPas or less). Further, it was found that the refractive index of the cured product was high (more than 1.67). On the other hand, it is clear that the epoxy polymerizable compositions obtained in comparative examples 1 to 4 have a low refractive index (1.67 or less). The epoxy polymerizable compositions obtained in comparative examples 5 to 6 were clouded, and the cured products thereof were clouded. The epoxy polymerizable composition obtained in comparative example 7 had a high cure shrinkage rate, had a refractive index of 1.65 or less, and was not sufficiently cured due to oxygen inhibition during film curing, and thus failed to form a film. The epoxy polymerizable composition obtained in comparative example 8 became pasty and was difficult to cure.

FIG. 3 is a graph showing the viscosity and the refractive index of a cured product of the epoxy polymerizable composition of examples 1 to 9 and the epoxy polymerizable composition of comparative examples 1 to 4. As shown in fig. 3, it is understood that the epoxy polymerizable composition obtained in the examples has a low viscosity and a high refractive index of the cured product.

The glass transition temperature (51 ℃ C. to 78 ℃ C.) of the cured products of the epoxy polymerizable compositions obtained in examples 1 to 6 was relatively higher than the glass transition temperature (42 ℃ C. to 59 ℃ C.) of the cured products of the epoxy polymerizable compositions obtained in examples 7 to 9. From these results, it was found that an epoxy resin cured product having excellent heat resistance can be obtained by adding a fluorene-based epoxy resin.

The cured products of the epoxy polymerizable compositions obtained in examples 1 to 9 had higher plasma resistance than those of comparative examples 9 and 10. From this, it is understood that the composition of the present invention is suitable for the production of an organic EL device exposed to plasma, and that the cured product of the composition of the present invention is also excellent in weather resistance.

Industrial applicability

The epoxy polymerizable composition of the present invention has a low viscosity even when a high shear force is applied, and can be easily molded by a printing method or the like, but the refractive index of the cured product thereof is high. Therefore, the sealing material is particularly suitable for use as a sealing material for optical devices, particularly light-emitting devices.

Description of the symbols

20. 20': organic EL device

22: display substrate

24: organic EL element

26: sealing substrate

28: sealing member

28-1: layer of cured material

28-2: passivation layer

28-3: adhesive resin layer

30: pixel electrode

32: organic EL layer

34: an opposite electrode.

Claims

1. An epoxy polymerizable composition comprising:

(A1) a sulfur-containing epoxy compound represented by the following general formula (i) and having a refractive index of 1.66 to 1.80;

(A2) an epoxy compound having a softening point of 70 ℃ or lower, wherein the above-mentioned (A1) sulfur-containing epoxy compound is excluded;

(A3) a fluorene-based epoxy compound represented by the following general formula (2) or (3);

(B) a curing accelerator; and

(C) 1a thiol compound having 2 or more thiol groups in a molecule; and is

A viscosity at 25 ℃ and 60rpm of 100 to 15000 mPas as measured by a B-type viscometer;

in the above-mentioned general formula (i),

X₁₁each independently represents-S-, -SO₂-、-O-、-C(R₂₁)₂-，R₂₁Each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,

Y₁₁and Y₁₂Each independently represents-O-or-S-,

Z₁and Z₂Each independently represents-O-or-S-,

m_arepresents any integer of 0 to 10,

n_aand k and m_cThe sum of which is A₂In the case of a benzene ring, 6 or less, in A₂In the case of a1, 3, 5-triazine ringIs a content of 3 or less in the total amount of the composition,

when m is_a1-10 times, from X₁₁、Y₁₁、Y₁₂、Z₁And Z₂At least one of the groups represented is an S-containing group;

in the general formula (2), in the formula,

R₁each independently represents a hydrogen atom or a methyl group;

R₂each independently represents a hydrogen atom or a methyl group;

R₃each independently represents an alkyl group having 1 to 5 carbon atoms;

R₄each independently represents an alkyl group having 1 to 5 carbon atoms;

m represents an integer of 2 or more;

n independently represents an integer of 0 to 3;

p independently represents an integer of 0 to 4;

q independently represents an integer of 0 to 5;

in the general formula (3), in the formula,

y represents a single bond, an oxygen atom or a sulfur atom;

q independently represents an integer of 0 to 4;

R₁～R₄m, n and p are defined as in the general formula (2).

2. The epoxy polymerizable composition according to claim 1, wherein the sulfur-containing epoxy compound represented by the general formula (i) is a sulfur-containing epoxy compound represented by the following general formula (1),

in the above-mentioned general formula (1),

x represents-S-or-SO₂-，

Y₁And Y₂Each independently represents-O-or-S-,

m represents any integer of 0 to 10,

m1 and n each independently represent any integer of 0 to 4,

when m is 0, Y₁And Y₂At least one of them is-S-.

3. The epoxy polymerizable composition according to claim 1, wherein the epoxy compound (A2) is at least 1 epoxy compound selected from the group consisting of bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, amino epoxy compounds, and epoxy compounds represented by the following general formula (4),

in the general formula (4), in the formula,

s is 0 to 4.

4. The epoxy polymerizable composition according to claim 1, wherein the (A2) epoxy compound is a trifunctional epoxy compound.

5. The epoxy polymerizable composition according to claim 1, wherein the thiol equivalent of the (C) thiol compound is 80 to 100 g/eq; and is

(C) The sulfur content of the thiol compound is 50% to 80%.

6. The epoxy polymerizable composition according to claim 1, wherein the molecular weight of the thiol compound (C) is 140 to 500.

7. The epoxy polymerizable composition according to claim 1, wherein the content of the (A1) sulfur-containing epoxy compound is 50 parts by mass or more and the content of the (A3) fluorene-based epoxy compound is 10 to 30 parts by mass, based on 100 parts by mass of the epoxy compound contained in the epoxy polymerizable composition.

8. The epoxy polymerizable composition according to claim 1, wherein a molar ratio of the epoxy group to the thiol group contained in the epoxy polymerizable composition is 1: 0.9 to 1.1.

9. The epoxy polymerizable composition according to claim 1, wherein the water content is 0.1% by mass or less.

10. A transparent resin for optical materials comprising the epoxy polymerizable composition according to claim 1.

11. An organic EL element surface sealing agent comprising the epoxy polymerizable composition according to claim 1.

12. A cured product of the epoxy polymerizable composition according to claim 1, which has a refractive index of 1.68 or more.

13. An organic EL device, comprising:

a display substrate on which an organic EL element is disposed;

an opposing substrate which is paired with the display substrate; and

a sealing member interposed between the display substrate and the counter substrate and filling a space formed between the organic EL element and the counter substrate;

the sealing member is a cured product of the epoxy polymerizable composition according to claim 1.

14. An organic EL device, comprising:

an organic EL element;

a sealing member which is in contact with the organic EL element; and

a passivation film in contact with the sealing member;

15. An organic EL display panel comprising the organic EL device according to claim 13 or 14.

16. A method of manufacturing an organic EL device, comprising:

a first step of forming an organic EL element on a display substrate;

a step 2 of sealing the organic EL element with the epoxy polymerizable composition according to claim 1;

a3 rd step of laminating an opposing substrate so as to oppose the display substrate with the composition interposed therebetween; and

and a 4 th step of curing the composition to form a sealing member.

17. A method of manufacturing an organic EL device, comprising:

a first step of forming an organic EL element on a substrate;

a3 rd step of curing the composition to form a sealing member; and

and a 4 th step of forming a passivation film on the sealing member.