KR20200062045A - Hygroscopic silicone resin composition, transparent sealing material for organic el, transparent drying material for organic el, and methods of using thereof - Google Patents

Abstract

An object of the present invention is to provide a transparent sealing material for organic EL and a hygroscopic silicone resin composition which have effects of being capable of highly transparent top emission, being highly transparent, inhibiting growth of a shrink amount and a loss of light-emitting element part (occurrence of dark spot) even at a high temperature and high humidity, and also inhibiting a short circuit phenomenon. Accordingly, the present invention provides a hygroscopic silicone resin composition, which comprises a silicone resin and a surface-treated hygroscopic silica particle having a covered part in which an organic silicon compound or a condensate thereof is bound on at least a part of a surface thereof, and in which a hygroscopic capacity is 1.0×10^-7 g/mm^3 or more, and provides a hygroscopic silicone resin composition in which both a refractive index of the silicone resin and a refractive index of the silica particle are 1.39 to 1.42, a content of the silica particle is 1 to 70 mass% with regard to the total resin composition, and the organic silicon compound is a tri-functional silane compound represented by formula, R^1Si(OR^4)_3, a silazane compound represented by formula, R^2_3SiNHSiR^2_3, or a mono-functional silane compound represented by formula, R^2_3SiX.

Description

Hygroscopic silicone resin composition, transparent sealing material for organic EL, transparent drying material for organic EL, and a method for using the same

The present invention relates to a hygroscopic silicone resin composition, a transparent sealing material for organic EL (electronic luminescence), a transparent drying material for organic EL, and a method of using the same.

The organic electronics luminescence (hereinafter abbreviated to organic EL) panel is a self-emission type, and since the element itself emits light, it does not require a separate light source, such as a backlight of a liquid crystal panel, so it is low power consumption, thinner and lighter. It has features such as ease of use, and is said to be of high quality compared to a liquid crystal panel. However, there is a problem that only a very small amount of moisture enters the panel and the device light emitting area is damaged (dark spots are generated).

Since the organic EL panel requires a structure that prevents highly moisture intrusion, a structure in which the organic EL element is sealed with a transparent substrate including glass or the like is generally used. This structure is a hollow sealing structure in which an organic EL element having a structure in which an anode, an organic layer, and a cathode are stacked on a substrate such as glass is formed, and facing opposite intaglio glass, etc., and dried inside (N ₂ ) It is obtained by filling with gas or the like, and further adhering the ends with a sealing material. At this time, for the purpose of removing moisture that has entered the organic EL panel, various studies have been reported, such as a method of installing a drying agent therein, or a method of covering an organic EL element with a filler. Either way, when the desiccant or filler has light-transmitting properties, the so-called top emission of extracting light generated by the organic EL element from the top surface to the outside becomes possible, which makes it more effective.

Further, the organic EL element is mainly formed by a process such as vapor deposition, but the presence of minute particles may cause a so-called shorting phenomenon in which the cathode and the anode are short-circuited. Moreover, when moisture absorbing particles etc. are mixed in the sealing material, such as resin, a short phenomenon may arise also by agglutination of moisture absorbing particles. When such a short phenomenon occurs, it is necessary to separate the elements surrounding the aggregates of the particles or moisture-absorbing particles with a laser or the like, causing a problem of partial loss of light emission or process increase.

In addition, the organic EL panel has a pursuit of thinness, and in addition to the thin panel, a thin panel having a curved shape or the like has attracted attention. In such a thin panel, resistance to bending is sometimes required, and not only thinness, but also flexibility is required.

In addition, organic EL panels having a flexible structure capable of bending are also attracting attention, and similarly, thinness and flexibility are required for each component such as a light-transmitting substrate, a drying agent, and a filler.

Patent Document 1 discloses that a drying agent such as zeolite or silica gel is added to a silicone resin and filled in an organic EL panel. In this method, when a desiccant in an amount necessary to suppress the loss of the luminous area of the organic EL light-emitting device due to moisture is added, the light-transmitting property is not obtained, so that the so-called top emi that extracts light generated by the organic EL device from the top surface to the outside The application to Sean becomes impossible.

In addition, Patent Document 2 discloses that an organometallic compound is mixed with a silicone resin as a catching component and filled in an organic EL panel. In this method, since the viscosity of the organometallic compound is high, it is desired to lower the viscosity by mixing with a silicone resin for handling. However, as the proportion of the silicone resin increases, there is a problem that light transmittance is not obtained.

Japanese Patent Publication No. 2017-183191 Japanese Patent Publication No. 2013-176751

The present invention has been made in view of the above circumstances, and a high-transmission top emission is possible, and the growth of the shrink amount and the loss of the device light-emitting portion (the occurrence of dark spots) are suppressed even under high temperature and high humidity, and the short phenomenon is suppressed. An object of the present invention is to provide a hygroscopic silicone resin composition that imparts a transparent sealing material for an organic EL and a transparent desiccant for an organic EL having an effect.

The present inventors conducted a careful study to achieve the above object, and as a result, a silicone resin having a specific refractive index and a surface-treated hygroscopic silica fine particle, and using a composition exhibiting hygroscopicity as a transparent sealing material or drying agent for organic ELs, top emie It has been discovered that it is possible to suppress the growth of the shrink amount under high temperature and high humidity and high transparency and high temperature and high humidity, and to suppress the occurrence of dark spots and shorts.

Accordingly, the present invention provides the following hygroscopic silicone resin composition, a transparent sealing material for organic EL, a transparent drying material for organic EL, and a method of using the same.

1. A hygroscopic silicone resin composition comprising a silicone resin and a surface-treated hygroscopic silica fine particle having a coating portion formed by bonding an organosilicon compound or a condensate thereof to at least a part of the surface, and having a moisture absorption capacity of 1.0×10 ⁻⁷ g/mm 2 or more. Wherein, the refractive index of the silicone resin and the refractive index of the silica fine particles are all 1.39 to 1.42, the content of the silica fine particle relative to the entire silicone resin composition is 1 to 70% by mass, and the organic silicon compound has the following formula ( A hygroscopic silicone resin composition characterized by being a trifunctional silane compound represented by II) and a silazane compound represented by the following formula (III) or a monofunctional silane compound represented by the following formula (IV).

R ¹ Si(OR ⁴ ) ₃ (II)

(However, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms, R ⁴ is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms.)

R ² ₃ SiNHSiR ² ₃ (III)

(However, R ² is the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms.)

R ² ₃ SiX (IV)

(However, R ² is the same as above. X is an OH group or a hydrolyzable group.)

2. The hygroscopic silicone resin composition according to the above 1, wherein the silica fine particles are sol-gel silica fine particles.

3. The hygroscopic silicone resin composition according to 1 or 2, wherein the median diameter in the volume-based particle size distribution of the surface-treated hygroscopic silica fine particles is 0.01 to 0.5 µm.

4. The hygroscopic silicone resin composition according to any one of 1 to 3, wherein the silicone resin contains the following components (A) to (C).

(A) a linear organopolysiloxane having at least two alkenyl groups in one molecule,

(B) an organohydrogenpolysiloxane having a hydrogen atom bonded to at least two silicon atoms in one molecule: 1.0 to 1 hydrogen atom bonded to the silicon atom in the component (B) to 1 mol of the silicon atom-bonded alkenyl group in the component (A) An amount equivalent to 2.0 moles, and

(C) hydrosilylation catalyst

5. As a method for producing the hygroscopic silicone resin composition according to any one of 1 to 4 above, the hygroscopic silicone resin composition characterized in that the surface-treated hygroscopic silica fine particles are produced by the following steps (A1) to (A4). Method of manufacture.

Process (A1): Formula (I)

Si(OR ³ ) ₄ (I)

(However, R ³ is a monovalent hydrocarbon group having 1 to 6 carbon atoms of the same or different kinds.)

Mixing of hydrophilic spherical silica fine particles containing SiO ₂ units by hydrolysis and condensation of a tetrafunctional silane compound represented by or a partial hydrolysis product thereof or a mixture thereof in a mixture of a hydrophilic organic solvent and water in the presence of a basic substance A process for obtaining a solvent dispersion,

Step (A2): To the mixed solvent dispersion of the hydrophilic spherical silica fine particles, the following formula (II)

R ¹ Si(OR ⁴ ) ₃ (II)

(However, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms, R ⁴ is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms.)

A trifunctional silane compound represented by or a partial hydrolysis product thereof or a mixture thereof is added to treat the surface of the hydrophilic spherical silica fine particles, thereby forming R ¹ SiO _3/2 units on the surface of the hydrophilic spherical silica fine particles ( However, R ¹ is the same as described above) to obtain a mixed solvent dispersion of the first surface-treated spherical silica fine particles,

Step (A3): A step of obtaining a mixed solvent concentrated dispersion of the first surface-treated spherical silica fine particles by removing and concentrating a part of the hydrophilic organic solvent and water from the mixed solvent dispersion of the first surface-treated spherical silica fine particles, and

Step (A4): To the mixed solvent concentrated dispersion of the first surface-treated spherical silica fine particles, the following formula (III)

R ² ₃ SiNHSiR ² ₃ (III)

(However, R ² is the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms.)

Silazane compound represented by, or the following formula (IV)

R ² ₃ SiX (IV)

(However, R ² is the same as above. X is an OH group or a hydrolyzable group.)

Adding a monofunctional silane compound represented by or a mixture thereof, and treating the surface of the first surface-treated spherical silica fine particles to R ² ₃ SiO _1/2 units (however, on the surface of the first surface-treated spherical silica fine particles) , R ² is the same as above) to obtain the second surface-treated silica fine particles

6. The transparent sealing material for organic EL containing the hygroscopic silicone resin composition in any one of said 1-4.

7. A transparent desiccant for organic EL containing a cured product of the hygroscopic silicone resin composition according to any one of 1 to 4 above.

8. The method of using the transparent sealing material for organic EL described in 6 above, wherein the transparent sealing material for organic EL is applied onto an organic EL element and cured.

9. The method of using the transparent sealing material for organic EL described in 6, wherein the transparent sealing material for organic EL is filled in a panel having an organic EL element therein and cured.

10. The method of using the transparent drying agent for organic EL described in 7 above, wherein the transparent drying agent for organic EL is used in a panel having an organic EL element therein.

The transparent sealing material for organic EL obtained from the hygroscopic silicone resin composition of the present invention is highly transparent and has a small growth in shrink amount even under high temperature and high humidity, and can also suppress breakage (occurrence of dark spots) of the organic EL element. Moreover, since the transparent sealing material for organic EL of this invention is highly transparent, it is applicable to the top emission type which transmits the light emitted from an organic EL element.

In addition, the method of using the transparent sealing material for organic EL and the drying agent of the present invention is applied directly on an organic EL element or placed in an organic EL panel, and from the flexibility of the silicone resin, as an organic EL panel having flexibility. It is applicable.

In addition, with respect to the transparent sealing material for organic EL of the present invention, a drying agent, and a method for using the same, the low-molecular siloxane in the sealing material diffuses and deposits in the organic EL panel, insulates the vicinity of minute particles present in the formation of the organic EL element, , It is possible to obtain an effect of suppressing a short-circuit phenomenon caused by a short circuit between the cathode and the anode through particles.

Further, according to the transparent sealing material for an organic EL of the present invention and a method of using the same, since the silica fine particles mixed as a hygroscopic material are excellent in dispersibility, it is also possible to obtain an effect of suppressing the development of a short phenomenon caused by aggregation of the hygroscopic material. .

1 is a schematic view for explaining a method of applying a transparent sealing material for an organic EL, which is an embodiment of the present invention, to an organic EL panel.
Fig. 2 is a schematic diagram showing an organic EL panel obtained by the method of Fig. 1;
Fig. 3 is a schematic view showing an organic EL panel produced without applying a transparent sealing material for organic EL in the panel.

Hereinafter, the present invention will be described in more detail.

The hygroscopic silicone resin composition of the present invention contains hygroscopic silica fine particles having a coating formed by bonding an organic silicon compound or a condensate thereof to at least a part of the silicone resin and the surface, and has a moisture absorption capacity of 1.0×10 ⁻⁷ g/mm 2 or more. It is a hygroscopic silicone resin composition, and the refractive index of the silicone resin and the refractive index of the silica fine particles are all 1.39 to 1.42, and the hygroscopic silicone resin composition has a content of the silica fine particles in the sealing material of 1 to 70% by mass.

[Silicone resin]

About the silicone resin in this invention, it is preferable to contain the following (A)-(C) component. Hereinafter, each component is explained in full detail.

(A) Linear organopolysiloxane having at least two alkenyl groups in one molecule

(B) an organohydrogenpolysiloxane having a hydrogen atom bonded to at least two silicon atoms in one molecule: 1.0 to 1 hydrogen atom bonded to the silicon atom in the component (B) to 1 mol of the silicon atom-bonded alkenyl group in the component (A) Mass equivalent to 2.0 mol

(C) hydrosilylation catalyst

(A) Alkenyl group-containing linear organopolysiloxane

(A) component in this invention is a linear organopolysiloxane which has at least 2 alkenyl groups in 1 molecule.

The alkenyl group-containing linear organopolysiloxane in the component (A) is a straight-chain organopolysiloxane having at least 2, preferably 2 to 8 alkenyl groups in one molecule. Specifically, the following formula (1)

(R ⁶ ₃ SiO _1/2 ) ₂ (R ⁶ ₂ SiO _2/2 ) _x (1)

It is an organopolysiloxane represented by.

In the formula (1), R ⁶ is independently a monovalent hydrocarbon group selected from an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an alkenyl group having 2 to 10 carbon atoms. As a specific example of a monovalent hydrocarbon group, alkyl groups, such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, cyclohexyl group, vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, cyclohexyl group And an alkenyl group such as a senyl group or an aryl group such as a phenyl group, and a methyl group is preferred from the viewpoint of making the refractive index of the silicone resin 1.39 to 1.42. The alkenyl group in the component (A) may have either a molecular chain terminal or a side chain, but it is preferable to have an alkenyl group only at the terminal. x is an integer of 100 to 50,000, preferably 150 to 20,000.

As a specific example of the said alkenyl group containing linear organopolysiloxane, trimethylsiloxy group block|block of both molecular chains dimethylsiloxane-methylvinylsiloxane copolymer, trimethylsiloxy group blocker of both molecular chains methylvinyl polysiloxane, trimethylsiloxy group blocker of both molecular chains Dimethylsiloxane/methylvinylsiloxane/methylphenylsiloxane copolymer, dimethylvinylsiloxy group at both ends of the molecular chain, dimethylpolysiloxane, dimethylvinylsiloxy group at both ends of the molecular chain, methylvinylpolysiloxane, dimethylvinylsiloxy group at both ends of the molecular chain, dimethylsiloxane, methyl Vinylsiloxane copolymer, molecular chain dimethylvinylsiloxy groups at both ends, dimethylsiloxane, methylvinylsiloxane, methylphenylsiloxane copolymer, molecular chain divinylmethylsiloxy groups at both ends, dimethylpolysiloxane, molecular chain divinylmethylsiloxy groups at both ends, dimethyl And siloxane-methylvinylsiloxane copolymers, trivinylsiloxy group-blocked dimethylpolysiloxanes at both molecular chain ends, and trivinylsiloxy group-blocked dimethylsiloxane-methylvinylsiloxane copolymers at both molecular chain ends.

The alkenyl group-containing linear organopolysiloxane may be used alone or in combination of two or more. When using two types of the said linear organopolysiloxane together, it is preferable that the weight average molecular weight of the organopolysiloxane of a low molecular weight side is 1,000-50,000, More preferably, it is 1,500-20,000. On the other hand, the weight average molecular weight of the organopolysiloxane on the high molecular weight side is preferably from 1,500 to 200,000, more preferably from 2,000 to 100,000. However, suppose that it is (weight average molecular weight on the low molecular side) <(weight average molecular weight on the high molecular side).

In addition, the weight average molecular weight in this invention can be calculated|required as the weight average molecular weight of polystyrene conversion in GPC (gel permeation chromatography) analysis.

Moreover, you may contain the alkenyl group containing resin organopolysiloxane as a component other than the alkenyl group containing linear organopolysiloxane of (A) component. However, from the viewpoint of suppressing the generation of bubbles during curing and deterioration of light transmittance, the content of the alkenyl group-containing resin-organopolysiloxane is preferably 1% by mass or less with respect to the component (A).

(B) organohydrogenpolysiloxane

The organohydrogenpolysiloxane of the component (B) in the present invention serves as a crosslinking agent to form a crosslinked structure by hydrosilylation with the alkenyl group-containing organopolysiloxane, and at least two silicon atoms in one molecule It is an organohydrogen polysiloxane having a hydrogen atom bonded to it.

Examples of the organohydrogenpolysiloxane of the component (B) include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane and tris(hydrogendimethylsiloxy)methyl Silane, tris(hydrogendimethylsiloxy)phenylsilane, methylhydrogencyclopolysiloxane, methylhydrogensiloxane-dimethylsiloxane cyclic copolymer, trimethylsiloxy group at both ends of the molecular chain, methylmethyl hydrogen polysiloxane, trimethylsiloxy group at both ends of the molecular chain Blocked dimethylsiloxane·methylhydrogensiloxane copolymer, molecular chain at both ends of the trimethylsiloxy group Blocked dimethylsiloxane·methylhydrogensiloxane·methylphenylsiloxane copolymer, molecular chain at both ends of the trimethylsiloxy group blocked dimethylsiloxane·methylhydrogensiloxane·diphenyl Siloxane copolymer, dimethylhydrogen siloxy group at both ends of the molecular chain, methylhydrogenpolysiloxane, dimethylhydrogen siloxy group at both ends of the molecular chain, dimethylpolysiloxane, dimethylhydrogen siloxy group at both ends of the molecular chain, dimethylsiloxane, methylhydrogensiloxane copolymer Copolymer, dimethylhydrogen siloxy group at both ends of the molecular chain, dimethylsiloxane·methylphenylsiloxane copolymer at both ends of the molecular chain, dimethylhydrogen siloxy group at both ends of the molecular chain, dimethylsiloxane·diphenylsiloxane copolymer at both ends of the molecular chain, methylphenyl at the ends of the molecular chain Polysiloxane, dimethylhydrogen siloxy group-blocked diphenylpolysiloxane at both ends of the molecular chain, or in each of these exemplary compounds, a part or all of the methyl group is substituted with another alkyl group such as an ethyl group or a propyl group, Formula: R ₃ SiO _1/ siloxane units represented by the formula _2: R siloxane units and represented by the ₂ HSiO _1/2: with R ₂ HSiO _1/2: organosiloxane copolymer, type comprising a siloxane unit represented by SiO _4/2 Organosiloxane copolymer comprising a siloxane unit represented by formula and a siloxane unit represented by SiO _4/2 , Formula: A siloxane unit represented by RHSiO _2/2 and formula: A siloxane unit represented by RSiO _3/2 or formula : Organosiloxane copolymer containing siloxane unit represented by HSiO _3/2 And mixtures comprising two or more of these organopolysiloxanes.

The blending amount of the component (B) is an amount corresponding to 1.0 to 2.0 moles of hydrogen atoms bonded to the silicon atom in the component (B) with respect to 1 mole of the silicon atom-bonded alkenyl group in the component (A), preferably 1.0 to 1.5 moles It is equivalent to.

(C) hydrosilylation catalyst

In the hydrosilylation catalyst of the component (C) in the present invention, when the alkenyl group-containing organopolysiloxane of the component (A) and the organohydrogenpolysiloxane of the component (B) are crosslinked by a hydrosilylation reaction It is a catalyst.

As a catalyst for the hydrosilylation reaction, a platinum group metal-based catalyst is preferable, and specifically, platinum black, a second platinum chloride, chloroplatinic acid, a reactant of chloroplatinic acid and a monohydric alcohol, a complex of chloroplatinic acid and olefins, chloroplatinic acid and vinyl group And platinum group metal-based catalysts such as a complex of a containing (poly)siloxane, a platinum-acetylacetone complex, and a platinum-cyclopentadienyl complex.

Moreover, as a component (C), you may use what is inactive under light shielding, and changes to an active platinum group metal catalyst by irradiating light with a wavelength of 200 to 500 nm. A platinum group metal catalyst is mentioned as a specific example of such (C) component, Especially, platinum group element compounds, such as ruthenium, rhodium, palladium, and platinum, are preferable, Especially, it is preferable that it is a platinum compound. Examples of the platinum compound include a β-diketone platinum complex or a platinum complex having a cyclic diene compound in a ligand. These compounds may be synthesized or commercial products may be used.

Examples of the β-diketone platinum complex include, for example, trimethyl (acetylacetonato) platinum complex, trimethyl (2,4-pentanedionate) platinum complex, trimethyl (3,5-heptanedionate) platinum complex, and trimethyl ( Methyl acetoacetate) platinum complex, bis(2,4-pentanedionato) platinum complex, bis(2,4-hexanedionato) platinum complex, bis(2,4-heptanedionato) platinum complex, bis(3, 5-heptandionato) platinum complex, bis(1-phenyl-1,3-butanedionato) platinum complex, bis(1,3-diphenyl-1,3-propanedionato) platinum complex, and the like. , Preferably a bis(β-diketonato) platinum complex, more preferably a bis(acetylacetonato) platinum complex.

Examples of the platinum complex having the cyclic diene compound in the ligand are (η ⁵ -cyclopentadienyl)dimethyl platinum complex, (η ⁵ -cyclopentadienyl)diphenyl platinum complex, (η ⁵ -cyclopentadiee Neil) dipropyl platinum complex, (2,5-norbornadiene)dimethyl platinum complex, (2,5-norbornadiene)diphenyl platinum complex, (η ⁵ -cyclopentadienyl)dimethyl platinum complex, ( η ⁵ -methylcyclopentadienyl)diethyl platinum complex, (η ⁵ -trimethylsilylcyclopentadienyl)diphenyl platinum complex, (η ⁵ -methylcyclooctadienyl)diethyl platinum complex, (η ⁵ -cyclo Pentadienyl)trimethyl platinum complex, (η ⁵ -cyclopentadienyl)ethyldimethyl platinum complex, (η ⁵ -cyclopentadienyl)acetyldimethyl platinum complex, (η ⁵ -methylcyclopentadienyl)trimethyl platinum complex, (η ⁵ -methylcyclopentadienyl)trihexyl platinum complex, (η ⁵ -trimethylsilylcyclopentadienyl)trimethyl platinum complex, (η ⁵ -dimethylphenylsilylcyclopentadienyl)triphenyl platinum complex, and (η ⁵ -cyclopentadienyl)dimethyltrimethylsilylmethyl platinum complex and the like, preferably (η ⁵ -methylcyclopentadienyl)trialkyl platinum complex, more preferably (η ⁵ -methylcyclopentadienyl) ) It is a trimethyl platinum complex.

The blending amount of the component (C) is not particularly limited as long as it is an amount that promotes the curing (hydrosilylation reaction) of the resin composition of the present invention, but from the viewpoints of curability, storage stability, and cost, the components (A) and (B) are The amount which becomes 0.5 to 1,000 ppm in terms of a platinum group metal amount with respect to the total of the mass is preferable, and more preferably 1 to 500 ppm.

Other ingredients

In addition to the components (A) to (C), the silicone resin of the present invention may be added with other components within a range not impairing the operational effects of the present invention. Specifically, it contains at least one functional group selected from a reaction control agent for a hydrosilylation reaction, an adhesion-imparting material (especially, alkenyl group, epoxy group, amino group, (meth)acryloxy group, mercapto group, etc. in the molecule) In addition, organosilicon compounds such as functional alkoxysilanes that do not contain SiH groups in the molecule), thixotropic agents, and the like.

The refractive index of the silicone resin used in the present invention is in the range of 1.39 to 1.42. When the refractive index is outside this range, the transparency of the resulting cured product is impaired as the difference in refractive index between the silica fine particles increases.

[Surface treated hygroscopic silica fine particles]

The surface-treated hygroscopic silica fine particles used in the present invention are hygroscopic silica fine particles having a coating portion formed by bonding an organic silicon compound or a condensate thereof to at least a part of the surface.

The organosilicon compound is a trifunctional silane compound represented by the following formula (II), a silazane compound represented by the following formula (III), or a monofunctional silane compound represented by the following formula (IV).

R ¹ Si(OR ⁴ ) ₃ (II)

(However, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms, R ⁴ is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms.)

R ² ₃ SiNHSiR ² ₃ (III)

(However, R ² is the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms)

R ² ₃ SiX (IV)

(However, R ² is the same as above. X is an OH group or a hydrolyzable group.)

In the formula (II), R ¹ is usually 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, particularly preferably 1 to 2 carbon atoms. Is a hydrocarbon group. Examples of the monovalent hydrocarbon group represented by R ¹ include, for example, alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, butyl group, and hexyl group, preferably methyl group, ethyl group, n-propyl group, Isopropyl groups, particularly preferably methyl groups and ethyl groups. Moreover, a part or all of the hydrogen atoms of these monovalent hydrocarbon groups may be substituted with halogen atoms such as fluorine atom, chlorine atom and bromine atom, preferably fluorine atom.

In the formula (II), R ⁴ is usually a monovalent hydrocarbon group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, and particularly preferably 1 to 2 carbon atoms. Examples of the monovalent hydrocarbon group represented by R ⁴ include alkyl groups such as methyl group, ethyl group, propyl group and butyl group, and preferably methyl group, ethyl group, propyl group, particularly preferably methyl group and ethyl group. Can be mentioned.

As the trifunctional silane compound represented by the formula (II), for example, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane , n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, trifluoropropyltrimethoxysilane, And trialkoxysilanes such as heptadecafluorodecyltrimethoxysilane, and preferably methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and more preferably Is methyltrimethoxysilane, methyltriethoxysilane, or partial hydrolysis condensation products thereof.

In the formulas (III) and (IV), R ² is a monovalent hydrocarbon group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, particularly preferably 1 to 2 carbon atoms. . Examples of the monovalent hydrocarbon group represented by R ² include, for example, alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group and butyl group, preferably methyl group, ethyl group, propyl group, particularly preferably methyl group and ethyl group. Can be mentioned. Moreover, a part or all of the hydrogen atoms of these monovalent hydrocarbon groups may be substituted with halogen atoms such as fluorine atom, chlorine atom and bromine atom, preferably fluorine atom.

Examples of the hydrolyzable group represented by X in the formula (IV) include chlorine atom, alkoxy group, amino group, acyloxy group, and the like, preferably alkoxy group, amino group, particularly preferably alkoxy group. to be.

As a silazane compound represented by said Formula (III), hexamethyldisilazane, hexaethyl disilazane, etc. are mentioned, for example, Preferably hexamethyldisilazane is mentioned.

As a monofunctional silane compound represented by said Formula (IV), monosilaneol compounds, such as trimethyl silanol and triethyl silanol, monochlorosilanes, such as trimethylchlorosilane and triethylchlorosilane, and trimethylmethane, for example. Monoalkoxysilanes, such as monoalkoxysilanes, such as hydroxysilane and trimethylethoxysilane, monomethylsilanes, such as trimethylsilyldimethylamine and trimethylsilyl diethylamine, and trimethylacetoxysilane, are preferably trimethylsilanol. , Trimethylmethoxysilane, trimethylsilyldiethylamine, particularly preferably trimethylsilanol and trimethylmethoxysilane.

Synthetic silica fine particles are largely classified into combustion method silica, deflagration method silica, wet silica, and sol-gel method silica (so-called Stoeber method) according to its production method. Of these, silica by the sol-gel method is preferable because moisture can be efficiently adsorbed by a silanol group present therein.

Below, an example of the preferable manufacturing method of the surface-treated hygroscopic silica microparticles|fine-particles of this invention by sol-gel method is demonstrated.

The method for producing the surface-treated hygroscopic silica fine particles in the present invention,

Process (A1): Formula (I)

Si(OR ³ ) ₄ (I)

(However, R ³ is a monovalent hydrocarbon group having 1 to 6 carbon atoms of the same or different kinds.) The tetrafunctional silane compound or partial hydrolysis product thereof, or a mixture thereof, is hydrophilic in the presence of a basic substance. A step of obtaining a mixed solvent dispersion of hydrophilic silica fine particles containing SiO ₂ units by hydrolysis and condensation in a mixed solution of an organic solvent and water,

Step (A2): To the mixed solvent dispersion of the hydrophilic silica fine particles, the following formula (II)

R ¹ Si(OR ⁴ ) ₃ (II)

(However, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and R ⁴ is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms.)

By adding a trifunctional silane compound represented by or a partially hydrolyzed product thereof or a mixture thereof, the surface of the hydrophilic silica fine particles is treated, and R ¹ SiO _3/2 units on the surface of the hydrophilic silica fine particles (however, R ¹ is the same as described above), and the step of obtaining a mixed solvent dispersion of the first surface-treated silica fine particles,

Step (A3): a step of obtaining a mixed solvent concentrated dispersion of the first surface-treated silica fine particles by removing and concentrating a part of the hydrophilic organic solvent and water from the mixed solvent dispersion of the first surface-treated silica fine particles,

Step (A4): To the mixed solvent concentrated dispersion of the first surface-treated silica fine particles, the following formula (III)

R ² ₃ SiNHSiR ² ₃ (III)

(However, R ² is the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms) Silazane compound, or the following formula (IV)

R ² ₃ SiX (IV)

(However, R ² is the same as above. X is an OH group or a hydrolyzable group.)

A monofunctional silane compound represented by or a mixture thereof is added, and the surface of the first surface-treated silica fine particles is further treated to form R ² ₃ SiO _1/2 units on the surface of the first surface-treated silica fine particles (however , R ² is the same as above) to obtain the second surface-treated silica fine particles

It is a manufacturing method having.

That is, the silica fine particles of the present invention,

Process (A1): Synthesis process of hydrophilic silica fine particles,

Process (A2): Surface treatment process with trifunctional silane compound,

Process (A3): Concentration process,

Process (A4): Surface treatment process with monofunctional silane compound

Is obtained by Hereinafter, each process of process (A1)-(A4) is demonstrated in order.

-Process (A1): Synthesis process of hydrophilic silica fine particles-

In this step, formula (I):

Si(OR ³ ) ₄ (I)

(However, R ³ is a monovalent hydrocarbon group having 1 to 6 carbon atoms of the same or different kinds.)

A hydrophilic silica fine particle mixed solvent dispersion is obtained by hydrolyzing and condensing a tetrafunctional silane compound represented by or a partial hydrolysis product thereof or a mixture thereof in a mixture of a hydrophilic organic solvent and water in the presence of a basic substance.

Examples of the monovalent hydrocarbon group represented by R ³ include, for example, methyl group, ethyl group, propyl group, butyl group and phenyl group, preferably methyl group, ethyl group, propyl group, butyl group, particularly preferably methyl group and ethyl group. Can be. It is preferably an alkyl group having 1 to 4 carbon atoms, particularly preferably a methyl group or an ethyl group.

Examples of the tetrafunctional silane compound represented by the formula (I): Si(OR ³ ) ₄ include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane , Tetraphenoxysilane, and the like, preferably tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, particularly preferably tetramethoxysilane, tetraethoxysilane. have. Moreover, as a partial hydrolysis-condensation product of the tetrafunctional silane compound represented by Formula (I), methyl silicate, ethyl silicate, etc. are mentioned, for example.

The hydrophilic organic solvent is not particularly limited as long as it dissolves the tetrafunctional silane compound represented by the formula (I): Si(OR ³ ) ₄ , its partially hydrolyzed condensation product, and water, for example, Alcohols, cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, and cellosolve acetate; ketones such as acetone and methyl ethyl ketone; ethers such as dioxane and tetrahydrofuran And preferably alcohols, cellosolves, and particularly preferably alcohols.

As these alcohols, the following formula (V)

R ⁵ OH (V)

(Wherein, R ⁵ is a monovalent hydrocarbon group having 1 to 6 carbon atoms)

And alcohol represented by.

In the formula (V): R ⁵ OH, R ⁵ is preferably a monovalent hydrocarbon group having 1 to 4 carbon atoms, particularly preferably 1 to 2 carbon atoms. The monovalent hydrocarbon group represented by R ⁵ is, for example, an alkyl group such as methyl group, ethyl group, propyl group, isopropyl group or butyl group, preferably methyl group, ethyl group, propyl group, isopropyl group, more preferably A methyl group and an ethyl group are mentioned. Examples of the alcohol represented by the formula (V) include methanol, ethanol, propanol, isopropanol, butanol, and preferably methanol and ethanol. When the number of carbon atoms in the alcohol increases, the particle diameter of the resulting silica fine particles increases. Therefore, methanol is preferable in order to obtain the target small particle size silica fine particles.

Moreover, ammonia, dimethylamine, diethylamine, etc. are mentioned as said basic substance, Preferably ammonia, diethylamine, Especially preferably, ammonia is mentioned. After dissolving the required amount in water, these basic substances may be mixed with the obtained aqueous solution (basic) with the hydrophilic organic solvent.

At this time, the amount of water used is 0.5 to 5 moles based on 1 mole of the hydrocarbyloxy group of the tetrafunctional silane compound represented by the formula (I): Si(OR ³ ) ₄ and/or its partial hydrolysis condensation product. It is preferable, More preferably, it is 0.6-2 mol, More preferably, it is 0.7-1 mol. The molar ratio of the hydrophilic organic solvent to water is preferably 0.5 to 10 in mass ratio, more preferably 3 to 9, and still more preferably 5 to 8. At this time, as the amount of the hydrophilic organic solvent increases, the desired fine particle size silica fine particles.

The amount of the basic substance is 0.01 to 2 moles based on 1 mole of the hydrocarbyloxy group of the tetrafunctional silane compound represented by the formula (I): Si(OR ³ ) ₄ and/or its partial hydrolysis condensation product. It is preferable, More preferably, it is 0.02 to 0.5 mol, More preferably, it is 0.04 to 0.12 mol. At this time, the smaller the amount of the basic substance, the easier it is to become desired small particle size silica fine particles, and more likely to be large particle size silica fine particles.

The formula (I): hydrolysis and condensation of a tetrafunctional silane compound represented by Si(OR ³ ) ₄ is a known method, that is, in a mixture of a hydrophilic organic solvent containing a basic substance and water, the formula ( It is carried out by adding a tetrafunctional silane compound represented by I) or the like.

The concentration of the silica fine particles in the hydrophilic silica fine particle mixed solvent dispersion obtained in the step (A1) is generally 3 to 15% by mass, and preferably 5 to 10% by mass.

-Process (A2): Surface treatment process with trifunctional silane compound-

To the hydrophilic silica fine particle mixed solvent dispersion obtained in step (A1), the following formula (II)

R ¹ Si(OR ⁴ ) ₃ (II)

(However, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms, R ⁴ is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms)

By adding a trifunctional silane compound represented by or a partial hydrolysis product thereof, or a mixture thereof, and thereby treating the surface of the hydrophilic silica fine particles, R ¹ SiO _3/2 units on the surface of the hydrophilic silica fine particles (however, R ¹ is the same as above.) is introduced to obtain a mixed solvent dispersion of the first surface-treated silica fine particles.

This step (A2) is indispensable to suppress the aggregation of the silica fine particles in the next step, the concentration step (A3). If this aggregation cannot be suppressed, since the individual particles of the resulting silica-based powder cannot maintain the primary particle size, as a result, element breakage, reduction in transmittance, etc. may be caused in sealing of the organic EL element. Does not.

In the formula (II), R ¹ is usually 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, particularly preferably 1 to 1 carbon atom. 2 is a monovalent hydrocarbon group. Examples of the monovalent hydrocarbon group represented by R ¹ include, for example, alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, butyl group, and hexyl group, preferably methyl group, ethyl group, n-propyl group, Isopropyl groups, particularly preferably methyl groups and ethyl groups. Moreover, a part or all of the hydrogen atoms of these monovalent hydrocarbon groups may be substituted with halogen atoms such as fluorine atom, chlorine atom and bromine atom, preferably fluorine atom.

In the formula (II), R ⁴ is usually a monovalent hydrocarbon group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, and particularly preferably 1 to 2 carbon atoms. Examples of the monovalent hydrocarbon group represented by R ⁴ include alkyl groups such as methyl group, ethyl group, propyl group and butyl group, and preferably methyl group, ethyl group, propyl group, particularly preferably methyl group and ethyl group. Can be mentioned.

As the trifunctional silane compound represented by the formula (II), for example, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane , n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, trifluoropropyltrimethoxysilane, And trialkoxysilanes such as heptadecafluorodecyltrimethoxysilane, and preferably methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and more preferably Is methyltrimethoxysilane, methyltriethoxysilane, or partial hydrolysis condensation products thereof.

The addition amount of the trifunctional silane compound represented by the formula (II) is 0.001 to 1 mole per 1 mole of Si atoms of the hydrophilic silica fine particles, preferably 0.01 to 0.1 mole, particularly preferably 0.01 to 0.05 mole. When this addition amount is 0.01 mol or more, the dispersibility is improved and is preferable. Further, if the addition amount is 1 mol or less, aggregation of the silica fine particles does not occur, which is preferable.

About the concentration of the said silica fine particle in the mixed solvent dispersion liquid of the 1st surface-treated silica fine particle obtained by this process (A2), it is 3 mass% or more and less than 15 mass% normally, Preferably it is 5-10 mass %. When the concentration is 3% by mass or more, productivity is improved, and it is preferable, and if it is less than 15% by mass, aggregation of silica fine particles does not occur, which is preferable.

-Process (A3) Concentration process-

By removing and concentrating a part of the hydrophilic organic solvent and water from the first surface-treated silica fine particle mixture solvent dispersion obtained in the step (A2), a concentrated solvent concentrated dispersion of the first surface-treated silica fine particles concentrated as desired is obtained. At this time, a hydrophobic organic solvent may be added in advance or during the process. Regarding the hydrophobic solvent to be used, a hydrocarbon-based or ketone-based solvent is preferable. Specifically, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, etc. are mentioned, Preferably methyl isobutyl ketone is preferable. As a method of removing a part of a hydrophilic organic solvent and water, distillation removal, vacuum distillation removal, etc. are mentioned, for example. It is preferable that the concentration of silica microparticles|fine-particles obtained is 15-40 mass %, More preferably, it is 20-35 mass %, More preferably, it is 25-30 mass %. When the concentration of the silica fine particles is 15% by mass or more, the surface treatment of the subsequent process is good, and when the concentration of the silica fine particles is 40% by mass or less, aggregation of the silica fine particles does not occur, which is preferable.

In this step (A3), the silazane compound represented by the formula (III) and the monofunctional silane compound represented by the formula (IV) used as the surface treatment agent in the next step (A4) react with alcohol or water. Insufficient surface treatment, and then, when drying is performed, aggregation occurs, and it is indispensable to suppress the problem that the obtained silica powder cannot maintain the primary particle size.

-Process (A4): Surface treatment process with monofunctional silane compound-

To the mixed solvent concentrated dispersion of the first surface-treated silica fine particles obtained in step (A3), the following formula (III)

R ² ₃ SiNHSiR ² ₃ (III)

(However, R ² is the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms.)

Silazane compound represented by, or the following formula (IV)

R ² ₃ SiX (IV)

(However, R ² is the same as above. X is an OH group or a hydrolyzable group.)

By adding a monofunctional silane compound represented by or a mixture thereof, and further treating the surface of the first surface-treated silica fine particles, R ² ₃ SiO _1/2 units (however, on the surface of the first surface-treated silica fine particles) , R ² is the same as above) to obtain the second surface-treated silica fine particles. In this process, R ² ₃ SiO _1/2 units are introduced into the surface in a form of triorganosilylating the silanol group remaining on the surface of the first surface-treated silica fine particles by the above treatment.

In the formulas (III) and (IV), R ² is a monovalent hydrocarbon group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, particularly preferably 1 to 2 carbon atoms. Examples of the monovalent hydrocarbon group represented by R ² include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, and butyl group, and preferably methyl group, ethyl group, and propyl group, particularly preferably. A methyl group and an ethyl group are mentioned. Moreover, a part or all of the hydrogen atoms of these monovalent hydrocarbon groups may be substituted with halogen atoms such as fluorine atom, chlorine atom and bromine atom, preferably fluorine atom.

Examples of the hydrolyzable group represented by X in the formula (IV) include, for example, a chlorine atom, an alkoxy group, an amino group and an acyloxy group, preferably an alkoxy group, an amino group, particularly preferably an alkoxy group.

As a silazane compound represented by said Formula (III), hexamethyldisilazane, hexaethyl disilazane, etc. are mentioned, for example, Preferably hexamethyldisilazane is mentioned.

As a monofunctional silane compound represented by said Formula (IV), monosilaneol compounds, such as trimethyl silanol and triethyl silanol, monochlorosilanes, such as trimethylchlorosilane and triethylchlorosilane, and trimethylmethane, for example. Monoalkoxysilanes, such as monoalkoxysilanes, such as hydroxysilane and trimethylethoxysilane, monomethylsilanes, such as trimethylsilyldimethylamine and trimethylsilyl diethylamine, and trimethylacetoxysilane, are preferably trimethylsilanol. , Trimethylmethoxysilane, trimethylsilyldiethylamine, particularly preferably trimethylsilanol and trimethylmethoxysilane.

The amount of the silazane compound and the monofunctional silane compound used is preferably 0.1 to 0.5 mol, more preferably 0.2 to 0.4 mol, and particularly preferably 0.25 to 0.35 per 1 mol of Si atoms of the hydrophilic silica fine particles. Mall When this amount is 0.1 mol or more, the dispersibility becomes good and is preferable. Further, if the amount is 0.5 mol or less, it is economically advantageous and preferable.

About the obtained surface treatment hygroscopic silica fine particles, since it is easy to absorb moisture after drying, it is preferable to perform a dehydration treatment when adding and mixing with a silicone resin. Specifically, it is more suitable to provide a dehydration treatment step of drying the surface-treated hygroscopic silica fine particles at a temperature of 100 to 150°C under normal pressure or reduced pressure. By drying the surface-treated hygroscopic silica fine particles by this treatment, it is preferable to adjust the amount of water contained to 0.5 to 2.0% by mass (mass of the surface-treated hygroscopic silica fine particles).

The surface-treated hygroscopic silica fine particles of the present invention have a refractive index in the range of 1.39 to 1.42. When this refractive index is outside the above range, the difference in refractive index from the silicone resin increases, and thus the transparency of the obtained cured product is impaired.

It is preferable that the median diameter in the particle size distribution based on the volume of the primary particles of the surface-treated hygroscopic silica fine particles of the present invention is 0.01 to 0.5 µm. Within this range, the transparency of the silicone resin composition due to aggregation of the fine particles, damage to the device, and occurrence of shorts can be suppressed.

The amount of the surface-treated hygroscopic silica fine particles of the present invention needs to be in the range of 1 to 70% by mass relative to the entire silicone resin composition, and is preferably in the range of 10 to 70% by mass. When the addition amount exceeds 70% by mass, handling becomes difficult due to aggregation of particles, increase in viscosity, and the like, and defoaming becomes difficult, resulting in a decrease in the transmittance due to bubble content. In addition, in the organic EL panel, when the agglomerates come into contact with the element, there is a possibility that damage or short of the element occurs and stable light emission cannot be obtained.

With respect to the addition amount of the surface-treated silica fine particles hygroscopic, and the moisture absorption capacity of the added amount (amount of water absorption as possible) of the silicone resin composition is hygroscopic, which is 1.0 × 10 ^-7 g / ㎣ or more, preferably 1.0 × 10 ^{- 6} g/mm2 or more. When the moisture absorption capacity of this resin composition is less than 1.0×10 ⁻⁷ g/mm 3, sufficient hygroscopicity is not obtained, and durability when used in an organic EL panel is deteriorated.

In the hygroscopic silicone resin composition of the present invention, the method for mixing the silicone resin and the surface-treated hygroscopic silica fine particles is not particularly limited, and examples thereof include a mixing method in the following inert gas.

That is, it is preferable that the silicone resin to be prepared and the surface-treated hygroscopic silica fine particles are stored in an inert gas with a reduced water content. As the inert gas, N ₂ gas or Ar gas is preferable, and the moisture content is preferably 1 ppm or less.

In the inert gas, the specified amount of the silicone resin and the surface-treated hygroscopic silica fine particles are metered by electronic balance or the like, and mixed. After mixing, defoaming is performed using a rotating device using a centrifugal force, if necessary. When it is difficult to remove air bubbles, it is preferable to perform vacuum degassing or the like.

Transparent sealing material for organic EL

The hygroscopic silicone resin composition of the present invention is suitable as a transparent sealing material for organic EL because it is easy to obtain a cured product that is transparent and thin. Specifically, in the cured product sheet having a thickness of 25 µm, it is suitable to use a product having a total light transmittance of 90% or more measured by a method in accordance with JIS K 7361-1:1997. If the total light transmittance of the cured sheet does not reach 90%, it may be disadvantageous when used in an organic EL panel having a top emission structure.

In addition, the transparent sealing material for organic EL of the present invention needs to have a moisture absorption capacity of 1.0×10 ⁻⁷ g/mm 2 or more, and preferably 3.0×10 ⁻⁷ g/mm 2 or more. When a moisture absorbing capacity of less than 1.0 x 10 ^-7 g/mm 2 is used as a sealing material for an organic EL, the moisture absorption of the water flowing into the organic EL panel is poor, so that the durability of the organic EL is low.

Method for applying transparent sealing material for organic EL

The hygroscopic silicone resin composition can be applied on the organic EL element as a transparent sealing material. As the coating method, a conventional method such as a dispensing method, an injection method, or a screen printing method can be used. The film thickness when the transparent sealing material for organic EL is coated on an organic EL element is not particularly limited, but is preferably in the range of 1 to 300 µm when used in an organic EL panel having a flexible structure.

Further, depending on circumstances such as the case of manufacturing a thin panel, the hygroscopic silicone resin composition may be applied directly onto the organic EL device, or may be applied via an SiO or SiN film on the organic EL device.

When explaining the curing method of the transparent sealing material for organic EL, as a curing catalyst of the hygroscopic silicone resin composition, a hygroscopic silicone resin composition irradiated with ultraviolet light is prescribed using a platinum catalyst activated by irradiating light having a wavelength of 200 to 500 nm. It is preferable to use a method of curing by standing under an environment.

Examples of the ultraviolet irradiation method include a method of irradiating an appropriate amount of ultraviolet light using a UV-LED lamp having a wavelength of 365 nm, a metal halide lamp, or the like, and preferably a wavelength of 200 to 500 nm, more preferably Preferably, light of 200 to 350 nm is used. From the viewpoint of both curing speed and discoloration prevention, the temperature at the time of irradiation is preferably 20 to 80°C, the irradiation intensity is preferably 30 to 2,000 mW/cm 2, and the irradiation dose is 150 to 10,000 mJ/cm 2 desirable. The conditions for curing when the composition irradiated with ultraviolet light is left still are not particularly limited, but it is preferable to cure at 20 to 60°C for 1 minute to 1 day.

Filling method of transparent sealing material for organic EL

The hygroscopic silicone resin composition is useful for filling the organic EL panel as a sealing material. An organic EL panel to which the hygroscopic silicone resin composition of the present invention is applied is, for example, a glass substrate on which an organic EL element having a structure in which an anode, an organic layer, and a cathode are stacked, and opposing intaglio glass or flat plate glass It is suitable to have a hollow sealing structure back to back.

When describing an example of bonding a glass substrate on which an organic EL element is formed and opposing intaglio glass, the intaglio glass filled with the hygroscopic silicone resin composition inside is organic in a facility for bonding the substrate to the upper and lower surfaces in a vacuum. The glass substrate on which the EL elements are laminated and the engraved glass filled with the hygroscopic silicone resin composition are bonded while facing each other. At this time, an ultraviolet curable epoxy resin can be applied to the end of the intaglio glass with a dispenser or the like, so that the organic EL element and the hygroscopic silicone resin composition are in direct contact with the organic EL element, and the environment is sealed with an epoxy resin. It becomes a filling structure. In addition, it is preferable that the hygroscopic silicone resin composition is irradiated with ultraviolet rays before charging. Depending on the irradiation conditions of ultraviolet rays, it is possible to maintain the liquid state for a certain period of time after ultraviolet irradiation, and to gradually advance the curing.

Subsequently, while maintaining the filling structure, ultraviolet rays are irradiated to the end epoxy resin portion to complete the end sealing. The hygroscopic silicone resin composition gradually hardens and solidifies completely. In this way, the organic EL panel in which the hygroscopic silicone resin is filled in the panel is completed.

Transparent drying agent for organic EL

The cured product of the hygroscopic silicone resin composition of the present invention can be used as a transparent desiccant for organic EL for dehumidifying water vapor that has entered the organic EL, even when the organic EL element is not in contact with the organic EL panel.

Manufacturing method of transparent desiccant for organic EL

As a molding method of the transparent drying agent for organic EL, a known molding method can be appropriately selected in accordance with the shape or size of the target molded article. For example, molding methods such as injection molding, compression molding, injection molding, calender molding, extrusion molding, coating, and screen printing are exemplified. Curing conditions may be any known conditions in the molding method employed, generally 60 to 450°C, preferably 80 to 400°C, and more preferably 120 to 200°C for a few seconds to 1 day. It is molding time. Further, for the purpose of reducing the low-molecular-weight siloxane component remaining in the cured product, such as in an oven at 150 to 250°C, preferably 200 to 240°C, for 1 hour or more, preferably about 1 to 70 hours, more preferably It is also possible to perform post-curing (secondary vulcanization) for about 1 to 10 hours.

In addition, the hygroscopic silicone resin composition can be sheeted and used by conventional methods such as screen printing, calender molding, injection, and pressing, in addition to coating methods such as a dispensing method and an injection method. In this case, the silicone rubber sheet obtained by sheeting the hygroscopic silicone resin composition is preferably molded to a thickness of 1.0 µm to 2 mm, more preferably 1.0 µm to 1 mm. With such a range, the desired effect of the present invention can be obtained without increasing the total thickness of the organic EL device.

How to use the transparent desiccant for organic EL

The transparent desiccant for organic EL is particularly useful for use in an organic EL panel. In the organic EL panel using the transparent desiccant of the present invention, an organic EL device having a structure in which an anode, an organic layer, and a cathode are laminated on a substrate such as glass is formed, and a hollow sealing structure is placed against opposing intaglio glass or the like. Have In addition, as an example of using the transparent desiccant of the present invention, the organopolysiloxane composition is dropped or coated by dispensing or inkjet or the like into the interior of the engraved glass to cure the composition, thereby curing the engraved glass. In the organic EL panel produced by bonding, the transparent desiccant of the present invention can be loaded only above the organic EL element, and the desiccant is not in contact with the organic EL element. That is, in the method of using the transparent desiccant for organic EL, the process is easy because the preformed transparent desiccant is applied to the organic EL device in a non-contact manner, rather than a method without filling in the organic EL panel. In addition, the method of using the transparent desiccant, even if the transparent desiccant is not in contact with the organic EL element, the low-molecular siloxane in the desiccant is diffused and deposited in the organic EL panel to insulate the vicinity of microparticles present in the formation of the organic EL element. , It is possible to obtain an effect of suppressing a so-called short phenomenon in which the cathode and the anode are short-circuited through particles.

[Example]

Hereinafter, the present invention will be specifically described by showing examples and comparative examples, but the present invention is not limited to the following examples. In addition, in the unit of a compounding quantity, a part shows a mass part. In addition, Me represents a methyl group, Ph represents a phenyl group, and Vi represents a vinyl group. The refractive index was measured with a digital refractometer (Atago RX-9000α). The weight average molecular weight is a weight average molecular weight in terms of polystyrene in GPC (gel permeation chromatography) analysis.

(Preparation of silicone resin (Preparation Examples 1 to 3))

[Preparation Example 1]

As component (A), dimethylpolysiloxane blocked at both ends by Me ₂ ViSiO _1/2 units (weight average molecular weight 5,000), as component (B) organohydrogenpolysiloxane represented by the following average formula (2) (weight average molecular weight) The number of moles of hydrogen atoms per unit mass (mol/g) per unit mass bound to 4,000 silicon atoms was adjusted to be 1.2 with respect to the number of moles X (mol/g) per unit mass of the silicon atom-bonded vinyl group of component (A).

H _1.29 Me _0.72 SiO _1.98/2 (2)

In addition, as the component (C), a 2-(2-butoxyethoxy)ethyl acetate solution of bis(acetylacetonato) platinum (II) (1% by mass as a platinum element) was used as the components (A) and (B). 0.4% by mass based on the total of these, and the components (A) to (C) were kneaded for 10 minutes with a planetary mixer (Inoue Seisakusho PLMG-350) to obtain a liquid silicone resin having a refractive index of 1.402.

[Preparation Example 2]

A silicone resin having a refractive index of 1.441 was obtained in the same procedure as in Preparation Example 1 except that an organopolysiloxane having an average structure represented by the following formula (3) was used as the component (A).

(ViMe ₂ SiO) ₂ (Me ₂ SiO) ₅₀ (Ph ₂ SiO) ₅ (3)

[Preparation Example 3]

A silicone resin having a refractive index of 1.425 was obtained in the same procedure as in Preparation Example 1, except that an organopolysiloxane having an average structure represented by the following formula (4) was used as the component (A).

(ViMe ₂ SiO) ₂ (Me ₂ SiO) ₅₀ (Ph ₂ SiO) _2.5 (4)

(Synthesis of surface-treated hygroscopic silica fine particles (Synthesis Examples 1 to 5 and Comparative Synthesis Examples 1 to 3))

[Synthesis Example 1]

Process (A1): "Synthesis process of hydrophilic silica fine particles"

In a 3-liter glass reactor equipped with a stirrer, a dropping funnel, and a thermometer, 989.5 g of methanol, 135.5 g of water, and 66.5 g of 28 mass% ammonia water were added and mixed. The solution was adjusted to 35°C, and 436.5 g (2.87 mol) of tetramethoxysilane was added dropwise over 6 hours while stirring. Even after the dropping was completed, stirring was continued for 0.5 hour to hydrolyze to obtain a suspension of hydrophilic silica fine particles.

Step (A2): "Surface treatment step with trifunctional silane compound"

To the suspension obtained in the step (A1), 4.4 g (0.03 mol) of methyl trimethoxysilane was added dropwise at 25° C. over 0.5 hour, stirring was continued for 12 hours even after dropping, and the surface of the silica fine particles was treated. A surface-treated silica fine particle dispersion was obtained.

Process (A3): 「Concentration process」

Subsequently, an ester adapter and a cooling tube were installed in the glass reactor, and the dispersion obtained in the previous step was heated to 60 to 70° C. to distill off 1,021 g of a mixture of methanol and water to obtain a concentrated solvent-concentrated dispersion of the first surface-treated silica fine particles. Got. At this time, the silica fine particle content in the concentrated dispersion was 28% by mass.

Step (A4): "Surface treatment step with a monofunctional silane compound"

After adding 138.4 g (0.86 moles) of hexamethyldisilazane at 25°C to the concentrated dispersion obtained in the previous step, the dispersion was heated to 50 to 60°C and reacted for 9 hours to trimethylsilyl silica particles in the dispersion. It was angry. Subsequently, 186 g of the second surface-treated silica fine particles [1] were obtained by distilling off the solvent in the dispersion at 130° C. under reduced pressure (6,650 Pa).

[Synthesis Example 2]

In Synthesis Example 1, in the same manner as in the step (A1), the amount of methanol, water, and 28 mass% ammonia water was replaced with 1,045.7 g of methanol, 112.6 g of water, and 33.2 g of 28 mass% ammonia water. 2] 188 g was obtained.

[Synthesis Example 3]

Process (A1): "Synthesis process of hydrophilic silica fine particles"

To a 3 liter glass reactor equipped with a stirrer, a dropping funnel, and a thermometer, 623.7 g of methanol, 41.4 g of water, and 49.8 g of 28 mass% ammonia water were added and mixed. The solution was adjusted to 35°C, and while stirring, 1,163.7 g of tetramethoxysilane and 418.1 g of 5.4 mass% aqueous ammonia were simultaneously added, the former was added dropwise over 6 hours, and the latter over 4 hours. Even after the dropping of tetramethoxysilane, stirring was continued for 0.5 hour to hydrolyze to obtain a suspension of hydrophilic silica fine particles.

Step (A2): "Surface treatment step with trifunctional silane compound"

To the suspension obtained in the above step (A1), 11.6 g of methyl trimethoxysilane (0.01 equivalent in molar ratio relative to tetramethoxysilane) was added dropwise over 0.5 hours at 25° C., and stirred for 12 hours even after dropping, thereby treating the first surface. Silica fine particles were obtained.

Process (A3): 「Concentration process」

Subsequently, an ester adapter and a cooling tube were installed in a glass reactor, and 1,440 g of methyl isobutyl ketone was added to the dispersion obtained in the previous step, followed by heating to 80 to 110° C. to distill the mixture of methanol and water over 7 hours. , A mixed solvent-concentrated dispersion of first surface-treated silica fine particles was obtained.

Step (A4): "Surface treatment step with a monofunctional silane compound"

To the concentrated dispersion obtained in the previous step, 357.6 g of hexamethyldisilazane was added at 25°C, heated to 120°C, and reacted for 3 hours to trimethylsilylate the silica fine particles. Thereafter, the solvent was distilled off under reduced pressure to obtain 472 g of second surface-treated silica fine particles [3].

[Synthesis Example 4]

In step (A1), 469 g of surface-treated silica fine particles [4] were obtained by performing the same operation as in Synthesis Example 3 except that the hydrolysis temperature of tetramethoxysilane was 27°C.

[Synthesis Example 5]

In step (A1), the same operation as in Synthesis Example 3 was performed except that the hydrolysis temperature of tetramethoxysilane was set to 20°C to obtain 461 g of surface-treated silica fine particles [5].

[Comparative Synthesis Example 1]

Into a 0.3 liter glass reactor equipped with a stirrer and a thermometer, 100 g of deflagration silica (trade name: SO-C1, manufactured by Admatex) was added, and 1 g of pure water was added under stirring, sealed, and further added at 60° C. for 10 hours. It was stirred. Subsequently, after cooling to 25° C., 2 g of hexamethyldisilazane was added under stirring, sealed, and further stirred for 24 hours. The temperature was raised to 120° C., and the residual raw material and the generated ammonia were removed while passing nitrogen gas to obtain 100 g of surface-treated silica fine particles [6].

[Comparative Synthesis Example 2]

Into a 0.3 liter glass reactor equipped with a stirrer and a thermometer, 100 g of deflagration silica (trade name: SO-C1, manufactured by Admatex) was added, and 1 g of pure water was added under stirring, sealed, and further added at 60° C. for 10 hours. It was stirred. Subsequently, after cooling to 25° C., 1 g of methyltrimethoxysilane was added under stirring, sealed, and stirred for another 24 hours. Subsequently, 2 g of hexamethyldisilazane was added under stirring, sealed, and further stirred for 24 hours. The temperature was raised to 120°C, and the residual raw material and the generated ammonia were removed while passing nitrogen gas to obtain 101 g of surface-treated silica fine particles [7].

[Comparative Synthesis Example 3]

In the step (A4), the same procedure as in Synthesis Example 1 was carried out, except that hexamethyldisilazane was not added and the solvent in the dispersion was distilled off at 130° C. under reduced pressure (6,650 Pa). ] 179g was obtained.

The surface-treated silica fine particles (surface-treated silica fine particles [1] to [8]) obtained in Synthesis Examples 1 to 5 and Comparative Synthesis Examples 1 to 3 were measured according to the following method. Table 1 shows the results.

(Particle diameter)

The surface-treated silica fine particles are added to methanol to be 0.5 mass%, the ultrasonic particles are fired for 10 minutes to disperse the fine particles, and the dynamic light scattering method/laser Doppler method nanotrack particle size distribution measuring device (manufactured by Nikkiso Co., Ltd., The particle size distribution was measured by UPA-EX150), and the median diameter (50% cumulative diameter) in the particle size distribution based on the volume was taken as the particle diameter.

〔Refractive index〕

1 g of surface-treated silica fine particles were added to and dispersed in 20 g of a mixed solvent of toluene (refractive index 1.4962) and methyl isobutyl ketone (refractive index 1.3958). The refractive index was adjusted by the compounding ratio of the solvent, and the value of the refractive index of the mixed solvent when the dispersion had the highest visible light transmittance was taken as the refractive index of the surface-treated silica fine particles. In addition, the refractive index of the mixed solvent is a value at 25° C. measured with a digital refractometer (Atago RX-9000α), and the visible light transmittance of the dispersion is measured using a spectrophotometer (U-3900H, Hitachi Hi-Tech Science Co., Ltd.). The average value of light transmittance at a wavelength of 380 to 780 nm at 25°C was used.

〔Moisture content rate〕

10 mg of the surface-treated silica fine particles (surface-treated silica fine particles [1] to [8]) obtained in Synthesis Examples 1 to 5 and Comparative Synthesis Examples 1 to 3 were weighed in an aluminum container, and differential differential thermal balance (Rigaku Denki ( Note) Measurement was performed using the product type: TG8120), and the weight reduction rate at 25 to 200°C was used as the water content.

Moisture content (a) at moisture absorption when the surface-treated silica fine particles were exposed to atmospheric pressure at 30°C and 80RH% for 3 days, and moisture content at drying when dried for 2 days at a reduced pressure of 100°C and 100Pa. (b) was measured, and the hygroscopicity was evaluated by the difference [(a)-(b)(wt%pt)]. Moreover, in the surface-treated silica fine particles of the present invention, it is preferable that (a)-(b) is 4.0 wt%pt or more.

(Method for producing silicone resin composition)

The surface-treated silica fine particles obtained in the above Synthesis Examples were previously dehydrated at 100°C and 100 Pa under reduced pressure for 2 hours, sealed in a sealed container, and then left in a box substituted with an N ₂ gas whose moisture content was controlled to 1 ppm or less.

Further, after the silicone resin obtained in the preparation example was left in a box substituted with an N ₂ gas whose moisture content was controlled to 1 ppm or less for 2 hours, the surface-treated silica fine particles were added, and the surface-treated silica fine particles were subjected to a rotary stirring device. And dispersed for 30 minutes. Thereafter, defoaming treatment under reduced pressure was performed to obtain a silicone resin composition. In addition, the addition amount of the said surface-treated silica microparticles|fine-particles was weighted using the electronic balance.

[Examples 1 to 5, Comparative Examples 1 to 3]

According to the production method of the silicone resin composition, the surface-treated silica fine particles (surface-treated silica fine particles [1]) obtained in Synthesis Examples 1 to 5 and Comparative Synthesis Examples 1 to 3 in the silicone resin (refractive index 1.402) obtained in Preparation Example 1 A silicone resin composition was prepared by adding [8] to [1.0 mass%], "10.0 mass%", "50.0 mass%", and "70.0 mass%" with respect to the entire composition, respectively.

Subsequently, the silicone resin composition was coated on a polycarbonate plate having a dam formed at the end, leveled, and then, using a metal halide lamp (HANDY UV-100, manufactured by ORC), the cumulative irradiation amount was 4,000 at an ultraviolet intensity of 10 mW/cm 2. Cured by irradiation with mJ/cm 2. At that time, the coating amount was adjusted so that the size was 38 mm x 38 mm and the thickness was 25 µm. Then, it peeled from the polycarbonate plate, and the surface-treated silica fine particle containing silicone resin sheet was obtained.

〔Total light transmittance〕

About the obtained silicone resin sheet, the total light transmittance was measured with the transmittance measuring device (V-780 by Nippon Bunko Co., Ltd. product). When the total light transmittance was 90% or more, "○", 85% or more was evaluated as "Δ", and 85% or less was evaluated as "X". Table 2 shows the results.

〔Moisture absorption capacity〕

About the obtained silicone resin sheet, the weight before and after exposure for 3 days was measured under conditions of 40°C and 90% using a thermostat, and the moisture absorption obtained by dividing the obtained weight increase by the volume of the sheet (38 mm × 38 mm × 0.025 mm) The capacity (g/mm 2) was calculated. Table 2 shows the results.

As shown in Examples 1 to 5, when the surface-treated silica fine particles [1] to [5] having a refractive index of 1.396 were added to the silicone resin (refractive index 1.402) obtained in Preparation Example 1, the amount of silica fine particles added was total. The total light transmittance exceeded 90% in the range up to 70.0% by mass relative to the amount. Since the difference in refractive index between the silicone resin and the silica fine particles is small, it is considered that the light reflection at the interface of the surface-treated silica fine particles is small, and the high transmittance is exhibited.

On the other hand, as shown in Comparative Examples 1 and 2, the surface-treated silica fine particles [6] and [7] had a total light transmittance of 85% or more when the addition amount was 1.0 mass%, but if they were 10.0 mass% or more The total light transmittance resulted in less than 85%. This indicates that the surface-treated silica fine particles have a refractive index of 1.462, and loss of transmittance due to a difference in refractive index from the silicone resin is occurring.

In addition, as shown in Comparative Example 3, the surface-treated silica fine particles [8] have a refractive index of 1.396, but since the surface treatment of the silica fine particles is insufficient, aggregation of the silica fine particles occurs when mixing with the silicone resin, and the amount added Even at 1.0% by mass, the result was to impair the transmittance. It has been found that the surface treatment of the silica fine particles is important in order to obtain an effect that makes it difficult to cause aggregation.

[Comparative Examples 4 to 8]

In Examples 1 to 5, a silicone resin sheet was prepared in the same procedure as described above for a silicone resin composition in which the added amount of the surface-treated silica fine particles was 90.0% by mass relative to the total composition, respectively, of the moisture absorption capacity and the total light transmittance. Evaluation was performed. Table 3 shows the results.

As shown in Comparative Examples 4 to 8, when the added amount of the silica fine particles was 90.0% by mass, the total light transmittance remained above 85%. When the addition amount exceeds 90.0 mass%, when hydrophobic silica fine particles are added to the silicone resin, fluidity is impaired, aggregated particles are likely to be present, good dispersibility is not obtained, and defoaming becomes difficult, resulting in loss of transmittance. It becomes the result of making it small. Therefore, from the results of the above table, it can be seen that in order to obtain extremely good transmittance, the upper limit of the amount added is 70.0% by mass.

[Comparative Examples 9 to 14]

Subsequently, according to the manufacturing method of the silicone resin composition, in the silicone resin (refractive index 1.441) obtained in Preparation Example 2 and the silicone resin (refractive index 1.425) obtained in Preparation Example 3, in Synthesis Examples 1 and 3 and Comparative Synthesis Example 1 The obtained surface-treated silica fine particles (surface-treated silica fine particles [1], [3], and [6]) were "1.0 mass%", "10.0 mass%", "50.0 mass%" and "70.0 mass%" with respect to the whole composition, respectively. For the silicone resin composition added at each mass% of ”, a silicone resin sheet was produced in the same procedure as described above, and the moisture absorption capacity and total light transmittance were evaluated. Table 4 shows the results.

As shown in Comparative Examples 9 to 11, the surface-treated silica fine particles having a refractive index of 1.396 for the silicone resin (refractive index 1.441) obtained in Preparation Example 2 and the silicone resin (refractive index 1.425) obtained in Preparation Example 3 [1], [3] , And when the surface-treated silica fine particles [6] having a refractive index of 1.462 were added, a difference in refractive index from the silicone resin resulted in a total light transmittance of less than 85%.

( Method for manufacturing organic EL device )

The manufacturing method of the organic EL element to which the transparent sealing material for organic EL of this invention is applied is demonstrated with reference to (i)-(iv) of FIG. This manufacturing method includes an anode electrode 102, a hole injection layer 103, a hole transport layer 104, a light emitting layer 105, and an electron transport layer on an alkali-free glass 101 having a thickness of 1 mm and a size of 50 mm x 50 mm. (106), the electron injection layer 107 and the cathode electrode 108 are stacked to form an organic EL element laminated glass body 109 (see Fig. 1(i)).

Subsequently, in a box substituted with N ₂ gas with a controlled amount of water of 1 ppm or less, a non-alkali sealed type of concave intaglio shape with a thickness of 1 mm and a size of 42 mm × 42 mm shown in FIG. 1 (ii) prepared separately. UV curable epoxy resin 112 was applied to a portion of the glass 110 with a width of 2 mm at the intaglio end by a dispenser. In addition, the depth of the intaglio portion of the engraved glass was 25 μm.

Subsequently, in the same box, the silicone resin composition was prepared in a glass container as a transparent sealing material, and a metal halide lamp (HANDY UV-100, manufactured by ORC) was used to irradiate ultraviolet light with an ultraviolet intensity of 10 mW/cm 2 and an integrated irradiation amount of 2,000 mJ/cm 2 Was done. Subsequently, the transparent sealing material 111 after ultraviolet irradiation was filled in the engraved portion and a portion of size 38 mm x 38 mm (state shown in (iii) of FIG. 1).

Subsequently, as shown in FIG. 1(iv), the organic EL element laminated glass body 109 was bonded in the same box in the direction in which the organic layer was disposed inside the glass, before the transparent sealing material 111 cured. . Thereafter, a metal halide lamp (HANDY UV-100 manufactured by ORC) was used, and ultraviolet irradiation was performed to achieve an accumulated irradiation amount of 10,000 mJ/cm 2 at an ultraviolet intensity of 10 mW/cm 2, and then the epoxy resin was adhered, and then at 25° C. 3 The transparent sealing material was cured by standing still for time, and the organic EL panel 113 shown in FIG. 2 was obtained.

[Examples 6 to 8, Comparative Examples 15 and 16]

To the silicone resin (refractive index 1.402) obtained in Preparation Example 1, the surface-treated silica fine particles [1] (refractive index 1.396, particle diameter 52 nm) obtained in Synthesis Example 1 were "1.0 mass%" and "50.0 mass%" with respect to the entire composition, respectively. , Using the silicone resin composition mixed with each mass% of "70.0% by mass" and "90.0% by mass", the organic EL panel was produced in the procedure shown in the "Method for producing an organic EL device" column, and the following durability And the presence or absence of short defect occurrence was evaluated. Table 5 shows the results. In addition, the moisture absorption capacity was calculated in the same manner as in Example 1 and Comparative Example 4 above. In addition, the organic EL panel shown in Comparative Example 16 was not sealed with a silicone resin composition, and the inside of the glass panel was an organic EL panel in a state filled with dry N ₂ gas.

〔durability〕

The obtained organic EL panel was exposed to an environment of 60°C and 90%RH using a high-temperature and high-humidity test tank, taken out under air at 25°C at 200-hour intervals, and driven to emit light with a current density of 10 mA/cm 2, and an optical microscope. The size and number of dark spots were observed using (LV150N made by Nikon). When a dark spot having a diameter of 5 µm or more is targeted, a case in which the ratio of the total area of light emission of the dark spot is less than 3% of the total is "A: Particularly excellent. , And when it is 3% or more and less than 5%, "B: Excellent. ", and the case where it is 5% or more was evaluated as "C: inferior."

(With or without short defects)

The organic EL panel described above was exposed to an environment of 60°C and 90%RH for 1,000 hours using a high-temperature and high-humidity test tank, taken out under an atmosphere of 25°C, and then the presence or absence of short-circuiting of the organic EL panel was confirmed. The presence or absence of a short circuit confirms the presence or absence of light emission when a current of 10 mA/cm 2 or more is applied, and when there is no light emission, the presence or absence of a short mark on the cathode is confirmed. When light emission was reproduced by separating the device, the sample was identified as a short defect-producing sample. In addition, for each of the 5 samples, the number of samples in which a short defect occurred was indicated as the number [number of short defect occurrence samples/5].

As shown in Table 5, in Example 6, in the durability test of the organic EL panel, evaluation "B" was observed after 800 hours of occurrence of dark spots, but approximately good results were obtained. The amount of silica fine particles added was 1.0 mass%, and the moisture absorption of this panel was 4.0×10 ⁻⁷ g/mm 2. When the addition amount of the silica fine particles increases, the moisture absorption amount also increases, and as shown in Examples 7 and 8, the durability of the organic EL panel is also improved. Further, in Examples 6 to 8, no short occurrence was detected, and good results were obtained. However, as shown in Comparative Example 15, short generation was observed when the added amount of the silica fine particles was 90.0% by mass. This is considered to be caused by the contact of the organic EL element by the agglomerated particles and the small scratch loss.

Moreover, about the organic EL panel filled with dry nitrogen shown in the comparative example 16, in the same durability test, it became evaluation "B" at 200 hours, and evaluation "C" after 600 hours. This indicates that emission loss occurs because it does not have the ability to absorb moisture introduced into the organic EL panel.

[Examples 9 to 14]

To the silicone resin (refractive index 1.402) obtained in Preparation Example 1, the surface-treated silica fine particles [4] (refractive index 1.396, particle diameter 171 nm) obtained in Synthesis Example 4, and the surface-treated silica fine particles [5] (refractive index 1.396 obtained in Synthesis Example 5) , A particle size of 482 nm) using the silicone resin composition mixed with each of the mass% of "1.0 mass%", "50.0 mass%" and "70.0 mass%" with respect to the total composition, respectively, the above-mentioned "Method for producing organic EL device" The organic EL panel was produced in the procedure shown in the column, and the durability and the presence or absence of short defects were evaluated in the same manner as above. Table 6 shows the results.

As shown in Table 6, in Examples 9 to 11 and Examples 12 to 14, the same results as in Examples 6 to 8 were obtained, respectively.

[Comparative Examples 17 to 22]

To the silicone resin (refractive index 1.402) obtained in Preparation Example 1, the surface-treated silica fine particles [6] (refractive index 1.462, particle diameter 300 nm) obtained in Comparative Synthesis Example 1 and the surface-treated silica fine particles [7] (refractive index obtained in Comparative Synthesis Example 2) 1.462, the particle diameter of 300 nm) using the silicone resin composition mixed with each mass% of "1.0% by mass", "50.0% by mass" and "70.0% by mass" with respect to the entire composition, the production of the above-mentioned "organic EL element" Method" column, an organic EL panel was produced, and as described above, durability and short defect occurrence were evaluated. Table 7 shows the results.

As shown in Table 7, the organic EL panels of Comparative Examples 17 to 22 had good initial luminescence, but resulted in remarkably poor durability. This is considered to be because, as shown in Table 1, the hygroscopicity of the surface-treated silica fine particles [6] and [7] used was insufficient, so that moisture that had flowed into the organic EL panel could not be absorbed. The moisture absorption capacity of the sealing material at this time is 2.4×10 ⁻⁸ g/mm 2 and 2.2×10 ⁻⁸ g/mm ² , respectively, as shown in Comparative Example 19 and Comparative Example 22, and 4.0×10 ^-7 shown in Example 6. It is 1 digit smaller than g/ 작은.

101: alkali free glass
102: anode electrode
103: hole injection layer
104: hole transport layer
105: light emitting layer
106: electron transport layer
107: electron injection layer
108: cathode electrode
109: organic EL element laminated glass substrate
110: alkali-free engraved glass
111: transparent sealing material
112: UV curable epoxy resin
113: organic EL panel
114: organic EL panel (organopolysiloxane composition is invincible)

Claims (10)

It is a hygroscopic silicone resin composition comprising a silicone resin and surface-treated hygroscopic silica fine particles having a coating portion formed by bonding an organosilicon compound or a condensate thereof to at least a part of the surface, and having a moisture absorption capacity of 1.0×10 ⁻⁷ g/mm 2 or more, The refractive index of the silicone resin and the refractive index of the silica fine particles are all 1.39 to 1.42, the content of the silica fine particles relative to the entire silicone resin composition is 1 to 70% by mass, and the organosilicon compound is represented by the following formula (II) A hygroscopic silicone resin composition characterized by being a trifunctional silane compound represented by, and a silazane compound represented by the following formula (III) or a monofunctional silane compound represented by the following formula (IV).
R ¹ Si(OR ⁴ ) ₃ (II)
(However, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms, R ⁴ is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms.)
R ² ₃ SiNHSiR ² ₃ (III)
(However, R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms.)
R ² ₃ SiX (IV)
(However, R ² is the same as above. X is an OH group or a hydrolyzable group.) The hygroscopic silicone resin composition according to claim 1, wherein the silica fine particles are sol-gel silica fine particles. The hygroscopic silicone resin composition according to claim 1 or 2, wherein the median diameter in the volume-based particle size distribution of the surface-treated hygroscopic silica fine particles is 0.01 to 0.5 µm. The hygroscopic silicone resin composition according to claim 1 or 2, wherein the silicone resin contains the following components (A) to (C).
(A) a linear organopolysiloxane having at least two alkenyl groups in one molecule,
(B) An organohydrogenpolysiloxane having a hydrogen atom bonded to at least two silicon atoms in one molecule: 1.0 to 1 hydrogen atom bonded to a silicon atom in the component (B) to 1 mol of a silicon atom-bonded alkenyl group in the component (A) An amount equivalent to 2.0 moles, and
(C) hydrosilylation catalyst A method for producing the hygroscopic silicone resin composition according to claim 1 or 2, wherein the surface-treated hygroscopic silica fine particles are produced by the following steps (A1) to (A4). Manufacturing method.
Process (A1): Formula (I)
Si(OR ³ ) ₄ (I)
(However, R ³ is a monovalent hydrocarbon group having 1 to 6 carbon atoms of the same or different kinds.)
Mixing of hydrophilic spherical silica fine particles containing SiO ₂ units by hydrolysis and condensation of a tetrafunctional silane compound represented by or a partial hydrolysis product thereof or a mixture thereof in a mixture of a hydrophilic organic solvent and water in the presence of a basic substance A process for obtaining a solvent dispersion,
Step (A2): To the mixed solvent dispersion of the hydrophilic spherical silica fine particles, the following formula (II)
R ¹ Si(OR ⁴ ) ₃ (II)
(However, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms, R ⁴ is the same or different monovalent hydrocarbon group having 1 to 6 carbon atoms.)
A trifunctional silane compound represented by or a partial hydrolysis product thereof or a mixture thereof is added to treat the surface of the hydrophilic spherical silica fine particles, thereby forming R ¹ SiO _3/2 units on the surface of the hydrophilic spherical silica fine particles ( However, R ¹ is the same as described above) to obtain a mixed solvent dispersion of the first surface-treated spherical silica fine particles,
Step (A3): A step of obtaining a mixed solvent concentrated dispersion of the first surface-treated spherical silica fine particles by removing and concentrating a part of the hydrophilic organic solvent and water from the mixed solvent dispersion of the first surface-treated spherical silica fine particles, and
Step (A4): To the mixed solvent concentrated dispersion of the first surface-treated spherical silica fine particles, the following formula (III)
R ² ₃ SiNHSiR ² ₃ (III)
(However, R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 6 carbon atoms.)
Silazane compound represented by, or the following formula (IV)
R ² ₃ SiX (IV)
(However, R ² is the same as above. X is an OH group or a hydrolyzable group.)
Adding a monofunctional silane compound represented by or a mixture thereof, and treating the surface of the first surface-treated spherical silica fine particles to R ² ₃ SiO _1/2 units (however, on the surface of the first surface-treated spherical silica fine particles) , R ² is the same as above) to obtain the second surface-treated silica fine particles A transparent sealing material for an organic EL comprising the hygroscopic silicone resin composition according to claim 1 or 2. A transparent desiccant for organic EL containing a cured product of the hygroscopic silicone resin composition according to claim 1 or 2. A method of using the transparent sealing material for organic EL according to claim 6, wherein the transparent sealing material for organic EL is applied onto an organic EL element and cured. A method of using the transparent sealing material for organic EL according to claim 6, wherein the transparent sealing material for organic EL is filled in a panel having an organic EL element therein and cured. A method of using the transparent desiccant for organic EL according to claim 7, wherein the transparent desiccant for organic EL is used in a panel having an organic EL element therein.

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