JP7489607B2 - UV-curable resin composition, method for manufacturing organic EL light-emitting device, and organic EL light-emitting device - Google Patents

Description

The present invention relates to an ultraviolet-curable resin composition, a method for manufacturing an organic EL light-emitting device, and an organic EL light-emitting device. More specifically, the present invention relates to an ultraviolet-curable resin composition molded by an inkjet method, a method for manufacturing an organic EL light-emitting device using this ultraviolet-curable resin composition, and an organic EL light-emitting device including this encapsulant.

Organic EL light-emitting devices are used in lighting, displays, and other applications, and are expected to become more widespread in the future.

Among organic EL light-emitting devices, those known as top-emission types are constructed, for example, by placing an organic EL element on a support substrate, placing a transparent substrate opposite the support substrate, and filling the space between the support substrate and the transparent substrate with a transparent sealant. In this case, the light emitted by the organic EL element passes through the sealant and the transparent substrate and is emitted to the outside.

When organic EL elements deteriorate due to moisture, dark spots, which are areas that do not emit light, may appear. For this reason, the organic EL elements are covered with a passivation layer and a sealing substrate to prevent moisture from entering the organic EL elements from the outside (Patent Document 1).

Patent No. 6309787

However, if the adhesion between the sealing material and the passivation layer is insufficient, moisture may penetrate through the interface between the sealing material and the passivation layer.

The objective of the present invention is to provide an ultraviolet-curable resin composition that can be molded by an inkjet method and can form a cured product that has excellent adhesion to inorganic materials, a method for manufacturing an organic EL light-emitting device using this ultraviolet-curable resin composition, and an organic EL light-emitting device that includes an encapsulant made of a cured product of this ultraviolet-curable resin composition.

The ultraviolet-curable resin composition according to one embodiment of the present invention can be molded by an inkjet method and contains a radically polymerizable compound (A) and a photopolymerization initiator (B), and the radically polymerizable compound (A) contains a silicone compound (A1) having at least one methoxy group in one molecule.

The method for manufacturing an organic EL light-emitting device according to one aspect of the present invention is a method for manufacturing an organic EL light-emitting device that includes an organic EL element, a sealant that covers the organic EL element, and a passivation layer made of an inorganic material, the sealant and the passivation layer overlapping each other, and includes forming the ultraviolet-curable resin composition by an inkjet method, and then irradiating the ultraviolet-curable resin composition with ultraviolet light to cure it, thereby producing the sealant.

The organic EL light-emitting device according to one aspect of the present invention comprises an organic EL element, a sealant that covers the organic EL element, and a passivation layer made of an inorganic material, the sealant and the passivation layer overlapping each other, and the sealant is a cured product of the ultraviolet-curable resin composition.

According to one aspect of the present invention, it is possible to obtain an ultraviolet-curable resin composition that can be molded by the inkjet method and can form a cured product that has excellent adhesion to inorganic materials.

1 is a schematic cross-sectional view showing a first example of an organic EL light-emitting device according to one embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing a second example of an organic EL light-emitting device according to one embodiment of the present invention.

One embodiment of the present invention will be described below with reference to Figures 1 and 2.

The ultraviolet-curable resin composition according to this embodiment (hereinafter also referred to as composition (X)) contains a radically polymerizable compound (A) and a photopolymerization initiator (B). The radically polymerizable compound (A) contains a silicone compound (A1) having at least one methoxy group in one molecule.

Since the composition (X) contains the silicone compound (A1), the sealing material 5 formed from the cured product of the composition (X) has excellent adhesion to inorganic materials. This is thought to be because the methoxy group contained in the silicone compound (A1) enhances the wettability of the composition (X) with inorganic materials. When forming a passivation layer 6 made of an inorganic material on the organic EL element 4, the passivation layer 6 may not be formed uniformly due to the unevenness of the organic light-emitting layer 42 in the organic EL element 4. In addition, foreign matter may be mixed in when the passivation layer 6 is formed, and the passivation layer 6 may have an irregular shape. However, by forming the sealing material 5 on the passivation layer 6 using the composition (X) that has high wettability with inorganic materials, the composition (X) can spread sufficiently and flatten the passivation layer 6. Therefore, even when layers are laminated on the sealing material 5, the lamination of layers can be performed stably. In addition, since the cured product of the composition (X) has excellent adhesion to inorganic materials, the adhesion between the sealing material 5 and the passivation layer 6 is improved. This makes it difficult for moisture to penetrate through the interface between the sealing material 5 and the passivation layer 6, resulting in a highly reliable organic EL light-emitting device 1.

Composition (X) can be molded by the inkjet method. Since composition (X) has the composition described above, composition (X) can be stably ejected when forming a film made of composition (X) by the inkjet method.

The viscosity of composition (X) at 25°C is preferably 35 mPa·s or less. In this case, composition (X) can be better molded by the inkjet method. The viscosity of composition (X) at 25°C is more preferably 30 mPa·s or less, even more preferably 25 mPa·s or less, particularly preferably 20 mPa·s or less, and most preferably 15 mPa·s or less. The viscosity of composition (X) at 25°C is preferably 1 mPa·s or more, and more preferably 5 mPa·s or more.

The viscosity of the composition (X) at 40°C is preferably 35 mPa·s or less. In this case, no matter what the viscosity of the composition (X) at room temperature is, it is possible to lower the viscosity by slightly heating the composition (X). Therefore, by heating, the composition (X) can be molded better by the inkjet method. In addition, since the viscosity of the composition (X) can be lowered without significantly heating it, the composition (X) is less likely to change due to the volatilization of the components in the composition (X). The viscosity of the composition (X) at 40°C is more preferably 30 mPa·s or less, even more preferably 25 mPa·s or less, particularly preferably 20 mPa·s or less, and most preferably 15 mPa·s or less. The viscosity of the composition (X) at 25°C is preferably 1 mPa·s or more, and more preferably 5 mPa·s or more.

The viscosity of the composition (X) is measured using a rheometer at a shear rate of 100 s ⁻¹ . As the rheometer, for example, a model DHR-2 manufactured by Anton Paar Japan KK can be used.

Such a low viscosity of composition (X) at 25°C or 40°C can be achieved by the composition of composition (X) described in detail below.

When 20 mg of composition (X) is heated at 100°C for 30 minutes using a thermogravimetric analyzer, the volatility is preferably 1% or less. The volatility of composition (X) is defined as the percentage of the weight loss of composition (X) after treatment (the difference between the weight of composition (X) before treatment and the weight of composition (X) after treatment) relative to the weight of composition (X) before treatment. In this case, the low volatility of composition (X) can improve the storage stability of composition (X). In addition, outgassing is less likely to occur in the cured product of composition (X) and from the sealing material 5. Therefore, gaps due to outgassing are less likely to occur in the organic EL light-emitting device 1, for example, between the sealing material 5 and the passivation layer 6. If there are gaps in the organic EL light-emitting device 1, moisture may reach the organic EL element 4 through the gaps, but if there are less gaps, moisture is less likely to reach the organic EL element 4, and the organic EL element 4 is less likely to deteriorate due to moisture. The volatility of composition (X) can be determined by heating 20 mg of composition (X) at 100°C for 30 minutes using a thermogravimetric analyzer and calculating the weight loss after the treatment relative to the weight before the treatment. It is more preferable that the volatility of 20 mg of composition (X) when heated at 100°C for 30 minutes using a thermogravimetric analyzer is 1% or less. The lower limit of the volatility of composition (X) is not particularly limited, but may be, for example, 0.1% or more.

The glass transition temperature of the cured product of composition (X) is preferably 80°C or higher. In other words, it is preferable that composition (X) has the property of becoming a cured product with a glass transition temperature of 80°C or higher when cured. In this case, the cured product of composition (X) can have good heat resistance. Therefore, for example, when the cured product is subjected to a process involving an increase in temperature, the cured product is less likely to deteriorate. For example, when a passivation layer 6 is formed by overlaying it on a sealing material 5 made from composition (X), even if the sealing material 5 is heated by a deposition method such as a plasma CVD method, the sealing material 5 is less likely to deteriorate. The glass transition temperature of the cured product of composition (X) is more preferably 90°C or higher, and even more preferably 100°C or higher.

When the cured product of composition (X) has a thickness dimension of 10 μm, the total light transmittance is preferably 90% or more. In this case, when the cured product is applied to the encapsulant 5 in the organic EL light-emitting device 1, the extraction efficiency of the light that passes through the encapsulant 5 and is emitted to the outside can be particularly improved. Such light transmittance of the cured product can also be achieved by the composition of composition (X), which will be described in detail below.

This embodiment will be explained in more detail below.

1. Structure of the Organic EL Light Emitting Device First, the structure of the organic EL light emitting device will be described. The organic EL light emitting device 1 includes an organic EL element 4 and a sealing material 5 that covers the organic EL element 4. The sealing material 5 may cover the organic EL element 4 in a state of direct contact with the organic EL element 4, or may cover the organic EL element 4 with some layer interposed between the sealing material 5 and the organic EL element 4. Note that EL is an abbreviation for electroluminescence. The organic EL element 4 is also called an organic light emitting diode.

A first example of the structure of an organic EL light-emitting device 1 will be described with reference to FIG. 1. This organic EL light-emitting device 1 is a top-emission type. The organic EL light-emitting device 1 includes a support substrate 2, a transparent substrate 3 that faces the support substrate 2 with a gap therebetween, an organic EL element 4 on the surface of the support substrate 2 that faces the transparent substrate 3, and a sealant 5 that fills between the support substrate 2 and the transparent substrate 3. In addition, in the first example, the organic EL light-emitting device 1 includes a passivation layer 6 that covers the surface of the support substrate 2 that faces the transparent substrate 3 and the organic EL element 4. That is, the passivation layer 6 is interposed between the organic EL element 4 and the sealant 5 that covers the organic EL element 4.

The support substrate 2 is made of, for example, a resin material, but is not limited thereto. The transparent substrate 3 is made of a material having light-transmitting properties. The transparent substrate 3 is, for example, a glass substrate or a transparent resin substrate. The organic EL element 4 includes, for example, a pair of electrodes and an organic light-emitting layer between the electrodes. The organic light-emitting layer includes, for example, a hole injection layer, a hole transport layer, an organic light-emitting layer, and an electron transport layer, and these layers are stacked in the above order. Although only one organic EL element 4 is shown in FIG. 1, the organic EL light-emitting device 1 may include multiple organic EL elements 4, and the multiple organic EL elements 4 may form an array on the support substrate 2. The passivation layer 6 is made of an inorganic material. Examples of the inorganic material include silicon nitride and silicon oxide.

A second example of the structure of the organic EL light-emitting device 1 will be described with reference to FIG. 2. Elements common to the first example shown in FIG. 1 are given the same reference numerals as in FIG. 1, and detailed descriptions will be omitted as appropriate. The organic EL light-emitting device 1 shown in FIG. 2 is also of the top-emission type. The organic EL light-emitting device 1 comprises a support substrate 2, a transparent substrate 3 opposed to the support substrate 2 with a gap therebetween, an organic EL element 4 on the surface of the support substrate 2 opposed to the transparent substrate 3, and a sealing material 5 covering the organic EL element 4.

As in the first example, the organic EL element 4 includes, for example, a pair of electrodes 41, 43 and an organic light-emitting layer 42 between the electrodes 41, 43. The organic light-emitting layer 42 includes, for example, a hole injection layer 421, a hole transport layer 422, an organic light-emitting layer 423, and an electron transport layer 424, which are stacked in the above order.

The organic EL light-emitting device 1 includes a plurality of organic EL elements 4, which are arranged in an array 9 (hereinafter referred to as element array 9) on a support substrate 2. The element array 9 also includes a partition wall 7. The partition wall 7 is located on the support substrate 2 and separates two adjacent organic EL elements 4. The partition wall 7 is fabricated, for example, by forming a photosensitive resin material using a photolithography method. The element array 9 also includes connection wiring 8 that electrically connects the electrodes 43 and the electron transport layers 424 of adjacent organic EL elements 4. The connection wiring 8 is provided on the partition wall 7.

The organic EL light-emitting device 1 also includes a passivation layer 6 that covers the organic EL element 4. The passivation layer 6 is made of an inorganic material. Examples of inorganic materials include silicon nitride and silicon oxide. The passivation layer 6 includes a first passivation layer 61 and a second passivation layer 62. The first passivation layer 61 covers the element array 9 while being in direct contact with the element array 9, thereby covering the organic EL element 4. The second passivation layer 62 is disposed on the opposite side of the element array 9 with respect to the first passivation layer 61, and a gap is provided between the second passivation layer 62 and the first passivation layer 61. A sealant 5 is filled between the first passivation layer 61 and the second passivation layer 62. That is, the first passivation layer 61 is interposed between the organic EL element 4 and the sealant 5 that covers the organic EL element 4.

Furthermore, a second sealing material 52 is filled between the second passivation layer 62 and the transparent substrate 3. The second sealing material 52 is made of, for example, a transparent resin material. The material of the second sealing material 52 is not particularly limited. The material of the second sealing material 52 may be the same as or different from the sealing material 5.

The sealing material 5 in the organic EL light-emitting device 1 having the structure exemplified above can be produced from the ultraviolet-curable resin composition according to this embodiment. That is, the ultraviolet-curable resin composition is used to produce the sealing material 5 for the organic EL element 4. In other words, the ultraviolet-curable resin composition is preferably a composition for producing a sealing material, a composition for sealing an organic EL element, or a composition for manufacturing an organic EL light-emitting device.

2. UV-curable resin composition The UV-curable resin composition (hereinafter, also referred to as composition (X)) will be described.

As described above, composition (X) contains a radically polymerizable compound (A) and a photopolymerization initiator (B). When composition (X) is irradiated with ultraviolet light, a photopolymerization reaction is initiated by the photopolymerization initiator (B), and the radically polymerizable compound (A) is cured to produce a cured product. The components of composition (X) are described in more detail below.

As described above, the composition (X) contains a radically polymerizable compound (A). The radically polymerizable compound (A) has at least one radically polymerizable functional group. Examples of the radically polymerizable functional group include a (meth)acryloyl group and a vinyl group. Note that a (meth)acryloyl group means at least one of an acryloyl group and a methacryloyl group. In addition, "(meth)acrylic" means at least one of "acrylic" and "methacrylic".

The viscosity of the entire radical polymerizable compound (A) at 25°C is preferably 50 mPa·s or less. In this case, the radical polymerizable compound (A) can further reduce the viscosity of the composition (X). The viscosity of the entire radical polymerizable compound (A) at 25°C is more preferably 30 mPa·s or less, even more preferably 25 mPa·s or less, and particularly preferably 20 mPa·s or less. The lower limit of the viscosity of the entire radical polymerizable compound (A) at 25°C is not particularly limited, but is, for example, 3 mPa·s or more.

It is also preferable that the viscosity of the entire radical polymerizable compound (A) at 40°C is 50 mPa·s or less. In this case, the radical polymerizable compound (A) can further reduce the viscosity of the composition (X) when heated. The viscosity of the entire radical polymerizable compound (A) at 40°C is more preferably 30 mPa·s or less, even more preferably 25 mPa·s or less, and particularly preferably 20 mPa·s or less. The lower limit of the viscosity of the entire radical polymerizable compound (A) at 40°C is not particularly limited, but is, for example, 3 mPa·s or more.

The compounds that may be contained in the radical polymerizable compound (A) are described below.

The radically polymerizable compound (A) contains a silicone compound (A1) having at least one methoxy group in one molecule. The silicone compound (A1) means a compound having at least one methoxy group in one molecule and further having silicon. Since the silicone compound (A1) has a methoxy group, the wettability of the composition (X) with inorganic materials is improved, and the sealing material 5 formed from the composition (X) has excellent adhesion to inorganic materials.

The content of the silicone compound (A1) in the composition (X) is preferably 0.5% by mass or more and 40% by mass or less. When the content of the silicone compound (A1) in the composition (X) is within this range, the cured product of the composition (X) can have high adhesion to inorganic materials, and therefore the intrusion of moisture from the interface between the sealing material 5 and the passivation layer 6 can be further suppressed. The content of the silicone compound (A1) in the composition (X) is more preferably 0.5% by mass or more and 40% by mass or less, even more preferably 1% by mass or more and 30% by mass or less, and particularly preferably 1% by mass or more and 20% by mass or less.

The percentage of the silicone compound (A1) relative to the radical polymerizable compound (A) is preferably 0.5% by mass or more. In this case, the cured product of the composition (X) has a higher glass transition temperature and can have high adhesion to inorganic materials. The percentage of the silicone compound (A1) relative to the radical polymerizable compound (A) is more preferably 1% by mass or more. The percentage of the silicone compound (A1) relative to the radical polymerizable compound (A) may be, for example, 100% by mass or less, preferably 45% by mass or less, more preferably 33% by mass or less, and even more preferably 22% by mass or less.

When 20 mg of the silicone compound (A1) is heated at 100°C for 30 minutes using a thermogravimetric analyzer, the volatility is preferably 35% or less. The volatility of the silicone compound (A1) is defined as the percentage of the weight loss of the silicone compound (A1) after the treatment (the difference between the weight of the silicone compound (A1) before the treatment and the weight of the silicone compound (A1) after the treatment) relative to the weight of the silicone compound (A1) before the treatment. In this case, the silicone compound (A1) is unlikely to volatilize from the composition (X). Therefore, the volatility of the composition (X) can be reduced, and the storage stability is unlikely to be impaired. In addition, even if the silicone compound (A1) remains unreacted in the cured product of the composition (X) and in the sealing material 5, outgassing due to the silicone compound (A1) is unlikely to occur from the cured product and the sealing material 5. Therefore, gaps due to outgassing are unlikely to occur in the organic EL light-emitting device 1, for example, between the sealing material 5 and the passivation layer 6. Therefore, moisture is less likely to reach the organic EL element 4 through the gap, and deterioration of the organic EL element 4 due to moisture is more easily prevented. The volatility of the silicone compound (A1) can be determined by heating 20 mg of the silicone compound (A1) at 100°C for 30 minutes using a thermogravimetric analyzer and calculating the weight loss after the treatment relative to the weight before the treatment. It is more preferable that the volatility of 20 mg of the silicone compound (A1) when heated at 100°C for 30 minutes using a thermogravimetric analyzer is 1% or less. The lower limit of the volatility of the silicone compound (A1) is not particularly limited, but may be, for example, 0.1% or more.

The boiling point of the silicone compound (A1) is preferably 260°C or higher. In this case, the silicone compound (A1) is unlikely to volatilize from the composition (X) during storage and when the composition (X) is heated. Therefore, the volatility of the composition (X) can be reduced, and storage stability is unlikely to be impaired. In addition, even if the silicone compound (A1) remains unreacted in the cured product of the composition (X) and in the sealing material 5, outgassing due to the acrylic compound (A1) is unlikely to occur from the cured product and the sealing material 5. Therefore, gaps due to outgassing are unlikely to occur, for example, between the sealing material 5 and the passivation layer 6 in the organic EL light-emitting device 1. Therefore, moisture is unlikely to reach the organic EL element 4 through the gap, and deterioration of the organic EL element 4 due to moisture is easily prevented. The boiling point is the boiling point under normal pressure obtained by converting the boiling point under reduced pressure, and is determined by the method shown in, for example, Science of Petroleum, Vol.II. P.1281(1938). The boiling point of the silicone compound (A1) is preferably 280° C. or higher. The upper limit of the boiling point of the silicone compound (A1) is not particularly limited, but may be, for example, 300° C. or lower.

The viscosity of the silicone compound (A1) at 25°C is preferably 100 mPa·s or less. In this case, the silicone compound (A1) can further reduce the viscosity of the composition (X). The viscosity of the silicone compound (A1) at 25°C is more preferably 60 mPa·s or less, even more preferably 50 mPa·s or less, and particularly preferably 40 mPa·s or less. The lower limit of the viscosity of the silicone compound (A1) at 25°C is not particularly limited, but is, for example, 1 mPa·s or more.

It is preferable that the silicone compound (A1) has a (meth)acryloyl group as a photopolymerizable functional group. It is more preferable that the silicone compound (A1) has three or more (meth)acryloyl groups in one molecule. In this case, the cured product of the composition (X) has a higher glass transition temperature, and therefore the heat resistance of the cured product and the sealing material 5 can be improved.

Specific examples of silicone compounds (A1) having a (meth)acryloyl group include product numbers KR-513, X-40-2655A, X-12-1048, and KBM5803 manufactured by Shin-Etsu Chemical Co., Ltd. Specific examples of silicone compounds having a vinyl group include product numbers KBM1063 and KBM1083 manufactured by Shin-Etsu Chemical Co., Ltd. As the silicone compound (A1), one of the above may be used alone, or two or more may be used in combination.

The radically polymerizable compound (A) may contain a radically polymerizable compound (A2) other than the silicone compound (A1). That is, the radically polymerizable compound (A2) is a radically polymerizable compound that does not have at least one of a methoxy group and silicon.

When the radical polymerizable compound (A) contains a silicone compound (A1) and a radical polymerizable compound (A2), the percentage of the silicone compound (A1) relative to the radical polymerizable compound (A) is preferably 0.5% by mass or more and 45% by mass or less. By setting the percentage of the silicone compound (A1) to 0.5% by mass or more and 45% by mass or less, the adhesion of the cured product of the composition (X) to the inorganic material is further improved, and the intrusion of moisture from the interface into the organic EL element 4 can be suppressed. In addition, if the percentage of the silicone compound (A1) is 45% by mass or less, the glass transition temperature of the cured product of the composition (X) can be further increased. It is more preferable that the percentage of the silicone compound (A1) is 1% by mass or more and 33% by mass or less, and even more preferable that it is 1% by mass or more and 22% by mass or less.

The radically polymerizable compound (A2) contains, for example, an acrylic compound (a). The acrylic compound (a) contains at least one of a polyfunctional acrylic compound (a1) having two or more (meth)acryloyl groups in one molecule and a monofunctional acrylic compound (a2) having only one (meth)acryloyl group in one molecule.

When the radically polymerizable compound (A) contains a polyfunctional acrylic compound (a1), the polyfunctional acrylic compound (a1) can increase the glass transition temperature of the cured product, thereby improving the heat resistance of the cured product and the sealing material 5.

When the silicone compound (A1) does not contain a compound having two or more radically polymerizable functional groups, the amount of the polyfunctional acrylic compound (a1) is preferably 50% by mass or more based on the total amount of the radically polymerizable compound (A). When the silicone compound (A1) contains a compound having two or more radically polymerizable functional groups, the total amount of the compound having two or more radically polymerizable functional groups and the polyfunctional acrylic compound (a1) is preferably 50% by mass or more and 100% by mass or less based on the total amount of the radically polymerizable compound (A).

Examples of the polyfunctional acrylic compound (a1) include 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol oligoacrylate, diethylene glycol diacrylate, 1,6-hexanediol oligoacrylate, neopentyl glycol diacrylate, triethylene glycol diacrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, cyclohexane dimethanol diacrylate, tricyclodecane dimethanol diacrylate, bisphenol A polyethoxy diacrylate, bisphenol F polyethoxy diacrylate, pentatriestrol tetraacrylate, propoxylated (2) neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, tris (2-hydroxyethyl)isocyanurate triacrylate, pentaerythritol triacrylate, ethoxylated (3) trimethylolpropane triacrylate, propoxylated (3) glyceryl triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated (4) pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, 2-(2-ethoxyethoxy)ethyl acrylate, hexadiol diacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, tripropylene glycol triacrylate, bispentaerythritol hexaacrylate, ethylene glycol diacrylate, 1,6-hexanediol diacrylate, ethoxylated 1,6-hexanedi All diacrylate, polypropylene glycol diacrylate, 1,4-butanediol diacrylate, 1,9-nonanediol diacrylate, tetraethylene glycol diacrylate, 2-n-butyl-2-ethyl-1,3-propanediol diacrylate, hydroxypivalic acid neopentyl glycol diacrylate, hydroxypivalic acid trimethylolpropane triacrylate, ethoxylated phosphoric acid triacrylate, ethoxylated tripropylene glycol diacrylate, neopentyl glycol modified trimethylolpropane diacrylate, stearic acid modified pentaerythritol diacrylate, tetramethylolpropane triacrylate, tetramethylolmethane triacrylate, caprolactone modified trimethylolpropane triacrylate, propoxylated glycol Contains at least one compound selected from the group consisting of lyceryl triacrylate, tetramethylolmethane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, caprolactone-modified dipentaerythritol hexaacrylate, dipentaerythritol hydroxypentaacrylate, neopentyl glycol oligoacrylate, trimethylolpropane oligoacrylate, pentaerythritol oligoacrylate, ethoxylated neopentyl glycol di(meth)acrylate, propoxylated neopentyl glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, ethoxylated trimethylolpropane triacrylate, and propoxylated trimethylolpropane triacrylate.

The acrylic equivalent of the polyfunctional acrylic compound (a1) is preferably 150 g/eq or less, and more preferably 90 g/eq or more and 150 g/eq or less. The weight average molecular weight of the polyfunctional acrylic compound (a1) is, for example, 100 or more and 1000 or less, and more preferably 200 or more and 800 or less.

The polyfunctional acrylic compound (a1) preferably contains a compound having at least one of a benzene ring, an alicyclic ring, and a polar group. The polar group is, for example, at least one of an OH group and an NHCO group. In this case, the shrinkage when the composition (X) is cured can be particularly reduced. Furthermore, the adhesion between the cured product and a member made of an inorganic material can be increased. The polyfunctional acrylic compound (a1) preferably contains at least one compound selected from the group consisting of tricyclodecane dimethanol diacrylate, bisphenol A polyethoxy diacrylate, bisphenol F polyethoxy diacrylate, trimethylolpropane triacrylate, and pentatriestrol tetraacrylate. These compounds can particularly reduce the shrinkage when the composition (X) is cured. Furthermore, these compounds can also increase the adhesion between the cured product and a member made of an inorganic material.

The polyfunctional acrylic compound (a1) may contain an acrylic compound (a1-1) consisting of at least one compound selected from the group consisting of di(meth)acrylic acid esters of alkylene glycols, di(meth)acrylic acid esters of polyalkylene glycols, and di(meth)acrylic acid esters of alkylene oxide-modified alkylene glycols.

The number of carbon atoms of the alkylene glycol in the di(meth)acrylic acid ester of alkylene glycol is preferably 2 to 12, and more preferably 4 to 12. The alkylene glycol may be linear or branched, such as 1,3-butylene glycol and neopentyl glycol. In particular, the di(meth)acrylic acid ester of alkylene glycol preferably contains at least one compound selected from the group consisting of 1,4-butanediol diacrylate, 1,3-butylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, 1,4-butanediol dimethacrylate, 1,3-butylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol dimethacrylate, and 1,12-dodecanediol dimethacrylate. Examples of di(meth)acrylic acid esters of alkylene glycol include Sartoma product number SR213, Osaka Organic Chemical Industry Co., Ltd. product number V195, Sartoma product number SR212, Sartoma product number SR247, Kyoei Chemical Industry Co., Ltd. product name Light Acrylate NP-A, Sartoma product number SR238NS, Osaka Organic Chemical Industry Co., Ltd. product number V230, Daicel Corporation product number HDDA, Kyoei Chemical Industry Co., Ltd. product number 1,6HX-A, Osaka Organic Chemical Industry Co., Ltd. product number V260, Kyoei Chemical Industry Co., Ltd. product number 1,9-ND-A, Shin-Nakamura Chemical Co., Ltd. product number A-NOD-A, Sartoma product number CD595, Sartoma product number It is preferable that the composition contains at least one compound selected from the group consisting of SR214NS, Shin-Nakamura Chemical Co., Ltd. product number BD, Sartoma Co., Ltd. product number SR297, Sartoma Co., Ltd. product number SR248, Kyoei Chemical Co., Ltd. product name Light Ester NP, Sartoma Co., Ltd. product number SR239NS, Kyoei Chemical Co., Ltd. product name Light Ester 1,6HX, Shin-Nakamura Chemical Co., Ltd. product number HD-N, Kyoei Chemical Co., Ltd. product name Light Ester 1,9ND, Shin-Nakamura Chemical Co., Ltd. product number NOD-N, Kyoei Chemical Co., Ltd. product name Light Ester 1,10DC, Shin-Nakamura Chemical Co., Ltd. product number DOD-N, and Sartoma Co., Ltd. product number SR262.

The number of carbon atoms of the alkylene glycol in the di(meth)acrylic acid ester of polyalkylene glycol is, for example, 2 to 4. The polyalkylene glycol includes at least one selected from the group consisting of, for example, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. The greater the carbon number of the polyalkylene glycol, the higher the hydrophobicity of the cured product and the sealing material 5, and the less moisture is allowed to penetrate the sealing material 5. Therefore, it is particularly preferable that the polyalkylene glycol is propylene glycol. The degree of polymerization of the alkylene glycol is, for example, 2 to 7, preferably 2 to 6, and also preferably 2 to 3. It is preferable that the di(meth)acrylic acid ester of polyalkylene glycol contains at least one compound selected from the group consisting of diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, hexaethylene glycol dimethacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, tripropylene glycol dimethacrylate, and tritetramethylene glycol diacrylate. In addition, the di(meth)acrylic acid ester of polyalkylene glycol preferably contains at least one compound selected from the group consisting of Sartoma's product number SR230, Sartoma's product number SR508NS, Daicel's product number DPGDA, Sartoma's product number SR306NS, Daicel's product number TPGDA, Osaka Organic Chemical Industry's product number V310HP, Shin-Nakamura Chemical's product number APG200, Kyoei Chemical Industry Co., Ltd.'s product name Light Acrylate PTMGA-250, Sartoma's product number SR231NS, Kyoei Chemical Industry Co., Ltd.'s product name Light Ester 2EG, Sartoma's product number SR205NS, Kyoei Chemical Industry Co., Ltd.'s product name Light Ester 3EG, Mitsubishi Chemical's product name Acrylate HX, and Shin-Nakamura Chemical Co., Ltd.'s product number 3PG.

The di(meth)acrylic acid ester of alkylene oxide modified alkylene glycol contains, for example, propylene oxide modified neopentyl glycol. The di(meth)acrylic acid ester of alkylene oxide modified alkylene glycol contains, for example, EBECRYL145 manufactured by Daicel Corporation.

When the radical polymerizable compound (A) contains a monofunctional acrylic compound (a2), the monofunctional acrylic compound (a2) can suppress the shrinkage of the composition (X) during curing. In addition, the monofunctional acrylic compound (a2) can contribute to reducing the viscosity of the composition (X).

When the radical polymerizable compound (A) contains a monofunctional acrylic compound (a2), the percentage of the monofunctional acrylic compound (a2) relative to the total amount of the radical polymerizable compound (A) is preferably more than 0% by mass and less than 70% by mass. If the percentage of the monofunctional acrylic compound (a2) is more than 0% by mass, the monofunctional acrylic compound (a2) can suppress the shrinkage of the composition (X) during curing. It is even more preferable if the percentage of the monofunctional acrylic compound (a2) is 5% by mass or more. If the percentage of the monofunctional acrylic compound (a2) is 70% by mass or less, outgassing due to the monofunctional acrylic compound (a2) is unlikely to occur from the composition (X) and the cured product. In addition, if the amount of the monofunctional acrylic compound (a2) is 70% by mass or less, the amount of the polyfunctional component in the radical polymerizable compound (A) can be secured, so that the heat resistance of the cured product and the sealing material 5 can be particularly improved by the polyfunctional component. It is more preferable that the percentage of the monofunctional acrylic compound (a2) is 50% by mass or less, even more preferable that the percentage of the monofunctional acrylic compound (a2) is 40% by mass or less, and particularly preferable that the percentage is 30% by mass or less.

Examples of the monofunctional acrylic compound (a2) include isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, 4-tertiary butylcyclohexyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isooctyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, and 2-ethoxyethyl (meth)acrylate. acrylate, 3-methoxybutyl (meth)acrylate, ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxydixylethyl (meth)acrylate, ethyl diglycol (meth)acrylate, cyclic trimethylolpropane formal mono(meth)acrylate, imide (meth)acrylate, isoamyl (meth)acrylate, ethoxylated succinic acid (meth)acrylate, trifluoroethyl (meth)acrylate, ω-carboxypolycaprolactone mono(meth)acrylate, cyclohexyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, stearyl (meth)acrylate , diethylene glycol monobutyl ether (meth)acrylate, lauryl (meth)acrylate, isodecyl (meth)acrylate, isooctyl (meth)acrylate, octyl/decyl (meth)acrylate, tridecyl (meth)acrylate, caprolactone (meth)acrylate, ethoxylated (4) nonylphenol (meth)acrylate, methoxypolyethylene glycol (350) mono(meth)acrylate, methoxypolyethylene glycol (550) mono(meth)acrylate, phenoxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, benzyl (meth)acrylate, methylphenoxyethyl (meth)acrylate It contains at least one compound selected from the group consisting of acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, tribromophenyl (meth)acrylate, ethoxylated tribromophenyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, ethylene oxide adduct of 2-phenoxyethyl (meth)acrylate, propylene oxide adduct of 2-phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-methacryloyloxymethylcyclohexene oxide, and 3-(meth)acryloyloxymethylcyclohexene oxide.

The monofunctional acrylic compound (a2) preferably contains a compound having an alicyclic structure. The compound having an alicyclic structure contains at least one compound selected from the group consisting of, for example, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, and 4-tertiarybutylcyclohexyl (meth)acrylate.

It is also preferable that the monofunctional acrylic compound (a2) contains the compound (a21) shown in the following formula (10). In this case, the viscosity of the composition (X) is easily reduced, and the sealing material 5 made from the composition (X) is easily provided with adhesion to inorganic material members such as the passivation layer 6. In addition, the compound (a21) has a low viscosity but is not easily volatilized. Therefore, even if the composition (X) is stored, the composition (X) is not easily changed in composition due to the volatilization of the monofunctional acrylic compound (a2).

In formula (10), R ⁰ is H or a methyl group. X is a single bond or a divalent hydrocarbon group. Each of R ¹ to R ¹¹ is H, an alkyl group or -R ¹² -OH, R ¹² is an alkylene group, and at least one of R ¹ to R ¹¹ is an alkyl group or -R ¹² -OH. R ¹ to R ¹¹ are not chemically bonded to each other.

When X is a divalent hydrocarbon group, the carbon number of X is preferably 1 to 5, more preferably 1 to 3. The divalent hydrocarbon group is, for example, a methylene group, an ethylene group, or a propylene group. It is particularly preferable that X is a single bond or a methylene group. In this case, the compound (a21) has the advantage of having a small molecular weight and low viscosity.

When at least one of R ¹ to R ¹¹ is an alkyl group, the number of carbon atoms of the alkyl group is preferably 1 or more and 8 or less. The alkyl group is, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, or an octyl group. The alkyl group may be linear or branched. That is, for example, when the alkyl group is a butyl group, the butyl group may be a t-butyl group, a n-butyl group, or a sec-butyl group. When the alkyl group is a hexyl group, the hexyl group may be a t-hexyl group, a n-hexyl group, or a sec-hexyl group. When the alkyl group is an octyl group, the octyl group may be, for example, a t-octyl group. It is particularly preferable that the alkyl group is a methyl group or a t-butyl group. In this case, there is an advantage that the compound (a21) has a small molecular weight and a low viscosity.

In formula (10), it is preferable that an alkyl group or -R ¹² -OH is connected only to the 4-position of the cyclohexane ring. That is, it is preferable that at least one of R ⁶ and R ⁷ among R ¹ to R ¹¹ is an alkyl group or -R ¹² -OH, and each of the remaining is H. It is particularly preferable that only R ⁶ among R ¹ to R ¹¹ is an alkyl group or -R ¹² -OH, and each of the remaining is H. In this case, the compound shown in formula (10) can have good reactivity and is particularly likely to impart adhesion to the sealing material 5 with inorganic material members. This is thought to be because the cyclohexane ring in the compound shown in formula (10) has a boat-type conformation, and the bulky alkyl group or -R ¹² -OH at the 4-position is likely to be located in a pseudo-equatorial position. It is thought that the reactivity of the (meth)acryloyl group in the compound shown in formula (10) is enhanced by the compound shown in formula (10) having such a structure. Furthermore, when the compound represented by formula (10) has such a structure, the compound represented by formula (10) can increase the free volume in the sealing material 5. Therefore, it is considered that the interfacial free energy between the sealing material 5 and the member made of an inorganic material is likely to be small, and therefore the adhesion between the sealing material 5 and the member made of an inorganic material is likely to be high. The more bulky the alkyl group or -R ¹² -OH is, the more likely the alkyl group or -R ¹² -OH is to be located in a pseudo-equatorial position. From this viewpoint, the more carbon atoms the alkyl group or -R ¹² -OH has, the more preferable it is, and it is also preferable that the alkyl group or -R ¹² -OH has a branch. For example, it is preferable that the alkyl group or -R ¹² -OH is a t-butyl group.

In formula (10), it is also preferred that an alkyl group or -R ¹² -OH is connected only to each of the 3-position and 5-position of the cyclohexane ring. That is, it is preferred that, among R ¹ to R ¹¹ , at least one of R ⁴ and R ⁵ is an alkyl group or -R ¹² -OH, at least one of R ⁸ and R ⁹ is an alkyl group or -R ¹² -OH, and the remaining groups are each H. It is more preferred that, among R ¹ to R ¹¹ , at least one of R ⁴ and R ⁵ is an alkyl group or -R ¹² -OH, at least one of R ⁸ and R ⁹ is an alkyl group or -R ¹² -OH, and the remaining groups are each H. It is also more preferred that, among R ¹ to R ¹¹ , at least one of R ⁴ and R ⁵ is an alkyl group or -R ¹² -OH, at least one of R ⁸ and R ⁹ is an alkyl group or -R ¹² -OH, and the remaining groups are each H. In this case, the compound represented by formula (10) can have good reactivity and is particularly likely to impart adhesion to the sealing material 5 with inorganic material members. This is believed to be because the cyclohexane ring in the compound represented by formula (10) has a boat-shaped conformation, and the bulky alkyl group or -R ¹² -OH at each of the 3-position and 5-position are likely to be located at the pseudo-equatorial position. For this reason, similar to the case where an alkyl group or -R ¹² -OH is connected only to the 4-position of the cyclohexane ring, it is believed that the reactivity of the (meth)acryloyl group in the compound represented by formula (10) is enhanced, and the adhesion between the sealing material 5 and the inorganic material member is likely to be enhanced. The bulkier the alkyl group or -R ¹² -OH, the more likely the alkyl group or -R ¹² -OH is to be located at the pseudo-equatorial position. From this viewpoint, the more carbon atoms the alkyl group or -R ¹² -OH has, the more preferable it is, and it is also preferable that the alkyl group or -R ¹² -OH has a branch. For example, it is preferable that the alkyl group or -R ¹² -OH is a t-butyl group.

When at least one of R ¹ to R ¹¹ is -R ¹² -OH, the carbon number of R ¹² is preferably 1 to 5, and more preferably 1 to 3. R ¹² is, for example, a methylene group, an ethylene group, or a propylene group. It is particularly preferable that R ¹² is a methylene group. In this case, there is an advantage that the compound (a21) has a small molecular weight and a low viscosity.

In formula (10), it is particularly preferred that each of R ¹ to R ¹¹ is H or an alkyl group, and at least one of R ¹ to R ¹¹ is an alkyl group. In this case, the compound represented by formula (10) can have a particularly low viscosity, and therefore composition (X) can have a particularly low viscosity. Therefore, composition (X) can be particularly easily molded by the inkjet method.

It is preferable that compound (a21) contains at least one compound selected from the group consisting of compounds shown in the following formula (11), compounds shown in the following formula (12), and compounds shown in the following formula (13).

It is particularly preferred that the monofunctional acrylic compound (a2) contains at least one of the compounds shown in formula (11) and formula (12). In this case, it is particularly easy to reduce the viscosity of the composition (X), particularly easy to increase the glass transition temperature of the sealing material 5, and particularly easy to increase the adhesion between the sealing material 5 and the inorganic material member. In addition, the compounds shown in formula (11) and formula (12) are not easily volatilized, and therefore it is easy to improve the storage stability of the composition (X).

It is also preferred that the monofunctional acrylic compound (a2) contains a compound having a cyclic ether structure. The number of ring members in the cyclic ether structure in the compound having a cyclic ether structure is preferably 3 or more, more preferably 3 to 4. The number of carbon atoms contained in the cyclic ether structure is preferably 2 to 9, more preferably 2 to 6. The compound having a cyclic ether structure contains at least one compound selected from the group consisting of, for example, 3-methacryloyloxymethylcyclohexene oxide and 3-acryloyloxymethylcyclohexene oxide.

It is preferable that the monofunctional acrylic compound (a2) contains at least one compound having a viscosity of 20 mPa·s or less at 25°C. In this case, the viscosity of the composition (X) can be reduced.

It is preferable that the monofunctional acrylic compound (a2) contains at least one compound having a glass transition temperature of 80°C or higher. In this case, the cured product of the composition (X) may have a high glass transition temperature. It is more preferable that the monofunctional acrylic compound (a2) contains at least one compound having a glass transition temperature of 90°C or higher, and even more preferable that it contains at least one compound having a glass transition temperature of 100°C or higher.

It is preferable that the monofunctional acrylic compound (a2) contains at least one compound having a boiling point of 200°C or higher. In this case, the monofunctional acrylic compound (a2) is less likely to reduce the storage stability of the composition (X). It is even more preferable that the monofunctional acrylic compound (a2) contains at least one compound having a boiling point of 250°C or higher.

It is particularly preferred if the monofunctional acrylic compound (a2) contains at least one compound having a viscosity of 20 mPa·s or less at 25°C and a glass transition temperature of 80°C or more. It is also preferred if the monofunctional acrylic compound (a2) contains at least one compound having a viscosity of 20 mPa·s or less at 25°C and a boiling point of 200°C or more. It is also preferred if the monofunctional acrylic compound (a2) contains at least one compound having a glass transition temperature of 80°C or more and a boiling point of 200°C or more. It is particularly preferred if the monofunctional acrylic compound (a2) contains at least one compound having a viscosity of 20 mPa·s or less at 25°C, a glass transition temperature of 80°C or more, and a boiling point of 200°C or more.

In particular, it is preferable that the monofunctional acrylic compound (a2) contains at least one compound selected from the group consisting of isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, and 4-tertiarybutylcyclohexyl (meth)acrylate. Isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, and 4-tertiarybutylcyclohexyl (meth)acrylate have high glass transition temperatures, low viscosities, and high boiling points, and therefore can particularly enhance the properties of the composition (X), the curing agent, and the sealant 5.

It is preferable that the acrylic compound (a) contains a component (b) consisting of at least one compound having a viscosity of 20 mPa·s or less at 25°C. In this case, the component (a) can reduce the viscosity of the composition (X). The compound contained in the component (b) may be a compound contained in the polyfunctional acrylic compound (a1) or a compound contained in the monofunctional acrylic compound (a2).

The proportion of component (b) relative to the total amount of acrylic compound (a) is preferably 50% by mass or more and 100% by mass or less. In this case, the viscosity of composition (X) can be particularly reduced, making composition (X) particularly easy to apply by the inkjet method. The proportion of component (b) is more preferably 60% by mass or more, and even more preferably 70% by mass or more. In addition, the proportion of component (b) is more preferably 95% by mass or less, and even more preferably 90% by mass or less.

Component (b) preferably contains a compound having a glass transition temperature of 80°C or higher. That is, component (b) preferably contains a compound having a viscosity of 20 mPa·s or lower at 25°C and a glass transition temperature of 80°C or higher. In this case, component (b) can increase the glass transition temperature of the cured product while lowering the viscosity of composition (X). Component (b) more preferably contains a compound having a glass transition temperature of 90°C or higher, and even more preferably contains a compound having a glass transition temperature of 100°C or higher. There is no upper limit to the glass transition temperature of the compound contained in component (b), but it is, for example, 150°C or lower.

Component (b) can contain, for example, at least one compound selected from the group consisting of isobornyl acrylate, dicyclopentanyl acrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol 200 dimethacrylate, and polyethylene glycol 200 diacrylate.

The acrylic compound (a) may contain component (c) consisting of a compound having at least one skeleton selected from the group consisting of a dicyclopentadiene skeleton, a dicyclopentanyl skeleton, a dicyclopentenyl skeleton, and a bisphenol skeleton. Component (c) can increase the adhesion between the cured product and an inorganic material member. The compound contained in component (c) may be a compound contained in the polyfunctional acrylic compound (a1) or a compound contained in the monofunctional acrylic compound (a2). The compound contained in component (c) may be a compound contained in component (b).

The ratio of component (c) to the total amount of acrylic compound (a) is preferably 5% by mass or more and 50% by mass or less. When the ratio of component (c) is 5% by mass or more, the adhesion of the cured product is further improved. When the ratio of component (c) is 50% by mass or less, the viscosity of composition (X) can be reduced, making it easier to mold composition (X) by the inkjet method. The ratio of component (c) is more preferably 30% by mass or more, and even more preferably 40% by mass or less. The acrylic compound (a) does not necessarily need to contain component (c).

Component (c) can contain, for example, at least one compound selected from the group consisting of tricyclodecane dimethanol diacrylate, bisphenol A polyethoxydiacrylate, and bisphenol F polyethoxydiacrylate.

The radical polymerizable compound (A2) may contain a compound (d) having a radical polymerizable functional group other than a (meth)acryloyl group. The compound (d) has, for example, a vinyl group as a radical polymerizable functional group. The compound (d) may contain either one or both of a polyfunctional radical polymerizable compound (d1) having two or more radical polymerizable functional groups in one molecule and a monofunctional radical polymerizable compound (d2) having only one radical polymerizable functional group in one molecule. The amount of the compound (d) relative to the radical polymerizable compound (A) is, for example, 10% by mass or less. The polyfunctional radical polymerizable compound (d1) may contain, for example, at least one compound selected from the group consisting of aromatic urethane oligomers, aliphatic urethane oligomers, epoxy acrylate oligomers, polyester acrylate oligomers, and other special oligomers having two or more ethylenic double bonds in one molecule. The monofunctional radical polymerizable compound (d2) contains at least one compound selected from the group consisting of, for example, N-vinylformamide, vinylcaprolactam, vinylpyrrolidone, phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, 1,2-butylene oxide, 1,3-butadiene monoxide, 1,2-epoxydodecane, epichlorohydrin, 1,2-epoxydecane, styrene oxide, cyclohexene oxide, 3-vinylcyclohexene oxide, 4-vinylcyclohexene oxide, N-vinylpyrrolidone, and N-vinylcaprolactam.

The composition (X) contains a photopolymerization initiator (B). The photopolymerization initiator (B) contains a photoradical polymerization initiator that generates radical species when irradiated with ultraviolet light. The photoradical polymerization initiator contains at least one compound selected from the group consisting of, for example, aromatic ketones, acylphosphine oxide compounds, aromatic onium salt compounds, organic peroxides, thio compounds (thioxanthone compounds, thiophenyl group-containing compounds, etc.), hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having carbon-halogen bonds, and alkylamine compounds. The amount of the photopolymerization initiator (B) relative to 100 parts by mass of the composition (X) is, for example, 1 part by weight or more and 10 parts by mass or less.

The photopolymerization initiator (B) may contain a sensitizer as a part of the photopolymerization initiator (B). The sensitizer can promote the photoradical generation reaction of the photopolymerization initiator (B) and improve the reactivity of the radical polymerization and the crosslinking density. The sensitizer may contain at least one compound selected from the group consisting of, for example, 9,10-dibutoxyanthracene, 9-hydroxymethylanthracene, thioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, anthraquinone, 1,2-dihydroxyanthraquinone, 2-ethylanthraquinone, 1,4-diethoxynaphthalene, p-dimethylaminoacetophenone, p-diethylaminoacetophenone, p-dimethylaminobenzophenone, p-diethylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, p-dimethylaminobenzaldehyde, and p-diethylaminobenzaldehyde.

The content of the sensitizer in the composition (X) is, for example, 0.1 parts by mass or more and 5 parts by mass or less, and preferably 0.1 parts by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the solid content of the composition (X). If the content of the sensitizer is within such a range, the composition (X) can be cured in air, and it is not necessary to cure the composition (X) in an inert atmosphere such as a nitrogen atmosphere.

The composition (X) may contain a polymerization accelerator in addition to the photopolymerization initiator (B). The polymerization accelerator contains, for example, an amine compound such as ethyl p-dimethylaminobenzoate, 2-ethylhexyl p-dimethylaminobenzoate, methyl p-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, or butoxyethyl p-dimethylaminobenzoate.

The composition (X) may further contain a hollow filler. The hollow filler can reduce the refractive index of the composition (X). The hollow filler preferably contains at least one of silica particles (hereinafter referred to as hollow silica particles) and resin particles (hereinafter referred to as hollow resin particles). In this case, the light transmittance of the cured product and the sealing material 5 is unlikely to be impaired by the hollow filler. In particular, when hollow resin particles that are unlikely to break even when force is applied are used as the hollow filler, the refractive index of the sealing material 5 is likely to be maintained low. The hollow resin particles are, for example, made of acrylic resin, that is, for example, hollow acrylic particles.

The hollow silica particles can contain, for example, Cataloid-Si manufactured by JGC Catalysts and Chemicals. The hollow acrylic particles can contain, for example, Tech Polymer NH series manufactured by Sekisui Chemicals.

The composition (X) may further contain a moisture absorbent. When the composition (X) contains a moisture absorbent, the cured product of the composition (X) and the sealing material 5 can have moisture absorption properties. Therefore, the sealing material 5 can further prevent moisture from penetrating into the organic EL element 4 in the organic EL light-emitting device 1. The average particle size of the moisture absorbent is preferably 200 nm or less. In this case, the cured product can have high transparency.

The moisture absorbent is preferably an inorganic particle having moisture absorbing properties, and preferably contains at least one component selected from the group consisting of zeolite particles, silica gel particles, calcium chloride particles, and titanium oxide nanotube particles. It is particularly preferable that the moisture absorbent contains zeolite particles.

Zeolite particles with an average particle size of 200 nm or less can be produced, for example, by crushing general industrial zeolite. When producing zeolite particles, the zeolite may be crushed and then crystallized by hydrothermal synthesis or the like, in which case the zeolite particles can have particularly high hygroscopicity. Examples of methods for producing such zeolite particles are disclosed in JP 2016-69266 A, JP 2013-049602 A, and the like.

When composition (X) contains a hollow filler, composition (X) preferably further contains a dispersant. In this case, the dispersant can improve the dispersibility of the hollow filler in composition (X). Therefore, composition (X) is less likely to suffer from an increase in viscosity and a decrease in storage stability due to the hollow filler.

Even when composition (X) contains a moisture absorbent, composition (X) preferably further contains a dispersant. In this case, the dispersant can improve the dispersibility of the moisture absorbent in composition (X). Therefore, composition (X) is less likely to experience an increase in viscosity and a decrease in storage stability due to the moisture absorbent.

The dispersant is a surfactant that can be adsorbed to particles. The dispersant has an adsorption group (generally called an anchor) that can be adsorbed to particles, and a molecular skeleton (generally called a tail) that attaches to the particles by adsorbing the adsorption group to the particles. The dispersant contains at least one component selected from the group consisting of, for example, an acrylic dispersant in which the tail is an acrylic molecular chain, a urethane dispersant in which the tail is a urethane molecular chain, and a polyester dispersant in which the tail is a polyester molecular chain. The adsorption group includes at least one of, for example, a basic polar functional group and an acidic polar functional group. The basic polar functional group includes at least one group selected from the group consisting of, for example, an amino group, an imino group, an amide group, an imide group, and a nitrogen-containing heterocyclic group. The acidic polar functional group includes at least one group selected from the group consisting of, for example, a carboxyl group and a phosphate group. The dispersant may contain at least one compound selected from the group consisting of, for example, the Solsperse series manufactured by Nippon Louvre Resol Co., Ltd., the DISPERBYK series manufactured by BYK Japan Co., Ltd., and the AJISPER series manufactured by Ajinomoto Fine-Techno Co., Ltd.

It is preferable that composition (X) does not contain a solvent. In this case, when preparing a cured product from composition (X), it is not necessary to dry composition (X) to volatilize the solvent. In addition, the storage stability of composition (X) is further improved.

Composition (X) can be prepared by mixing the above-mentioned components. Composition (X) is preferably liquid at 25°C.

3. Method for Producing Encapsulant and Method for Producing Organic EL Light-Emitting Device A method for producing the encapsulant 5 using the composition (X) and a method for producing the organic EL light-emitting device 1 will be described.

In this embodiment, it is preferable to mold the composition (X) by the inkjet method and then irradiate the composition (X) with ultraviolet light to harden it, thereby producing the sealing material 5. In this embodiment, it is possible to apply and mold the composition (X) by the inkjet method.

When applying composition (X) by the inkjet method, if composition (X) has a sufficiently low viscosity at room temperature, for example, if the viscosity at 25°C is 35 mPa·s or less, composition (X) can be molded by applying it by the inkjet method without heating.

When composition (X) has the property of being reduced in viscosity by heating, composition (X) may be heated and then applied by an inkjet method to form the composition (X). When composition (X) has a viscosity of 35 mPa·s or less at 40°C, composition (X) can be reduced in viscosity by simply heating it slightly, and this reduced-viscosity composition (X) can be ejected by an inkjet method. The heating temperature of composition (X) is, for example, 20°C or higher and 50°C or lower.

More specifically, for example, first, a support substrate 2 is prepared. A partition 7 is fabricated on one surface of the support substrate 2 by photolithography using, for example, a photosensitive resin material. Next, a plurality of organic EL elements 4 are provided on one surface of the support substrate 2. The organic EL elements 4 can be fabricated by an appropriate method such as a vapor deposition method or a coating method. It is particularly preferable to fabricate the organic EL elements 4 by a coating method such as an inkjet method. In this way, an element array 9 is fabricated on the support substrate 2.

Next, a first passivation layer 61 made of an inorganic material is provided on the element array 9. The first passivation layer 61 can be produced by a deposition method such as a plasma CVD method.

Next, the composition (X) is formed on the first passivation layer 61, for example, by an inkjet method, to produce a coating film. If the inkjet method is used for both the formation of the organic EL element 4 and the application of the composition (X), the manufacturing efficiency of the organic EL light-emitting device 1 can be particularly improved. Next, the coating film is cured by irradiating it with ultraviolet light to produce the sealant 5. The thickness of the sealant 5 is, for example, 5 μm or more and 50 μm or less.

Next, a second passivation layer 62 made of an inorganic material is provided on the sealing material 5. The second passivation layer 62 can be produced by a deposition method such as plasma CVD.

Next, an ultraviolet-curable resin material is applied to one surface of the support substrate 2 so as to cover the second passivation layer 62, and then the transparent substrate 3 is placed on top of this resin material. The transparent substrate 3 is, for example, a glass substrate or a transparent resin substrate.

Next, ultraviolet light is applied from the outside toward the transparent substrate 3. The ultraviolet light passes through the transparent substrate 3 and reaches the ultraviolet-curable resin material. This causes the ultraviolet-curable resin material to harden, producing the second sealing material 52.

As described above, in this embodiment, it is possible to prevent gaps from occurring between the passivation layer 6 and the sealing material 5 in the organic EL light-emitting device 1, and to prevent deterioration of the organic EL element due to the intrusion of moisture through these gaps.

1. Preparation of Compositions Compositions of the examples and comparative examples were prepared by mixing the components shown in the "Composition" column of Tables 2 and 3 below.

The details of the ingredients shown in Tables 2 and 3 are as follows:

(1) Radical Polymerizable Compound Among the components shown in Tables 2 and 3, the details of each component used as the radical polymerizable compound (A) are shown in Table 1 below. The viscosity of each component below is a value measured using a rheometer (manufactured by Anton Paar Japan, model number DHR-2) under conditions of a temperature of 25°C and a shear rate of 1000 s ^-1 . In addition, the volatility of the following radical polymerizable compounds is a percentage of the weight loss after heating to the weight before heating when 20 mg of the radical polymerizable compound is heated under conditions of 100°C for 30 minutes using a thermogravimetric analyzer (manufactured by Hitachi High-Technologies Corporation, model number STA7200RV).

(2) Photopolymerization initiator Irgacure 184: 1-hydroxycyclohexylphenylketone, manufactured by BASF Corporation, product name Irgacure 184.
Irgacure TPO: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, manufactured by BASF, product name Irgacure TPO.

The following evaluation tests were carried out on the examples and comparative examples. The results are shown in Table 2.

(1) Volatility Using a thermogravimetric analyzer (manufactured by Hitachi High-Technologies Corporation, model number STA7200RV), 20 mg of the composition was heated at 100° C. for 30 minutes. The percentage of the weight loss after heating relative to the weight before heating was calculated, and a percentage of less than 1% was rated as "A," a percentage of 1% or more but less than 2% was rated as "B," and a percentage of 2% or more was rated as "C."

(2) Viscosity The viscosity of the composition was measured using a rheometer (Model DHR-2, manufactured by Anton Paar Japan) at a temperature of 25° C. and a shear rate of 1000 s ⁻¹ .

(3) Inkjet properties The composition was placed in the cartridge of an inkjet printer (PX-B700, manufactured by Seiko Epson Corporation), and after confirming that the composition in the cartridge could be discharged from the nozzle of the inkjet printer, the composition was discharged from the nozzle to continuously print a test pattern. As a result, the case where the composition could be discharged for 1 hour and the discharge operation was stable was rated as "A", the case where the composition could be discharged for 1 hour but the discharge operation became intermittently unstable was rated as "B", and the case where the nozzle became clogged before 1 hour had passed since the start of discharge and the composition could no longer be discharged was rated as "C".

(4) Adhesion Two substrates were obtained by forming a silicon nitride film having a thickness of 1 μm on each surface of two pieces of quartz glass (dimensions 76 mm×52 mm×1 mm) by plasma CVD. A composition was applied to the surface of the silicon nitride film of one substrate to form a coating film having a thickness of 5200 μm, and the silicon nitride film of the other substrate was overlaid on the coating film. The coating film was then cured by irradiating it with ultraviolet light for 30 seconds under conditions of about 50 mW/cm2 using an LED-UV irradiator (peak wavelength 365 nm) manufactured by Panasonic Electric Works Co., Ltd. This resulted in the preparation of a test specimen.

The test piece was exposed to an atmosphere of 85°C and 85RH, and the state of the interface between the coating film and the silicon nitride film was then observed under a microscope. The results were evaluated as follows. In this test, the higher the adhesion between the coating film and the silicon nitride film and the less the coating film absorbs moisture, the less likely the coating film is to peel off from the silicon nitride film.
A: Even after exposure to the above atmosphere for 96 hours, 50% or more of the coating film remained in close contact with the silicon nitride film.
B: Even after 48 hours of exposure to the above atmosphere, 50% or more of the coating film area did not peel off from the silicon nitride film, but after 96 hours of exposure, 50% or more of the coating film area peeled off from the silicon nitride film.
C: Even after 24 hours of exposure to the above atmosphere, 50% or more of the coating film area did not peel off from the silicon nitride film, but after 48 hours of exposure, 50% or more of the coating film area peeled off from the silicon nitride film.
D: After exposure to the above atmosphere for 24 hours, 50% or more of the coating film area was peeled off from the silicon nitride film.

(5) Glass Transition Temperature A coating film was prepared by applying the composition, and this coating film was photocured by irradiating with ultraviolet light for 20 seconds under conditions of about 30 mW/ ^cm2 using an LED-UV irradiator (peak wavelength 365 nm) manufactured by Panasonic Electric Works Co., Ltd., to prepare a film having a thickness of 200 μm. The glass transition temperature of a sample cut out from this film was measured using a viscoelasticity measuring device (manufactured by Hitachi High-Tech Science Corporation, model number DMA7100).

(6) Heat Resistance The composition was applied onto a smooth table and then photocured by irradiating it with ultraviolet light for 10 seconds under conditions of a peak wavelength of 365 nm and an output of 300 mW/ ^cm2 using an LED-UV irradiator manufactured by Panasonic Electric Works Co., Ltd. As a result, a film having a thickness of 10 μm was produced.

The light transmittance (τ0) of this film at a wavelength of 430 nm was measured using a spectrophotometer U-4100 manufactured by Hitachi High-Technologies Corporation. The film was then heated at 120°C for 500 hours, after which the light transmittance (τ) of the film at a wavelength of 430 nm was measured. The light transmittance retention was calculated using the formula (τ/τ0) x 100, and the heat resistance was evaluated based on the results as follows:
A: Retention rate is 95% or more.
B: Retention rate is 90% or more but less than 95%.
C: Retention rate is less than 90%.

Claims (8)

An ultraviolet-curable resin composition that can be molded by an inkjet method,
Contains a radical polymerizable compound (A) and a photopolymerization initiator (B),
The radical polymerizable compound (A) contains a silicone compound (A1) having at least one methoxy group in one molecule,
The silicone compound (A1) has three or more (meth)acryloyl groups in one molecule,
The content of the silicone compound (A1) in the ultraviolet-curable resin composition is in the range of 17.4% by mass or more and 40% by mass or less.
Ultraviolet-curable resin compositions (excluding those containing a hydroxylation catalyst) . The viscosity at 25°C is 35 mPa·s or less.
The ultraviolet-curable resin composition according to claim 1 . The glass transition temperature of the cured product is 80° C. or higher.
The ultraviolet-curable resin composition according to claim 1 or 2. Contains no solvents
The ultraviolet-curable resin composition according to claim 1 . For sealing organic EL elements.
The ultraviolet-curable resin composition according to claim 1 . A method for manufacturing an organic EL light-emitting device comprising an organic EL element, a sealant covering the organic EL element and a passivation layer made of an inorganic material, the sealant and the passivation layer overlapping each other, comprising the steps of:
The method includes forming the ultraviolet-curable resin composition according to any one of claims 1 to 5 by an inkjet method, and then irradiating the ultraviolet-curable resin composition with ultraviolet light to cure the composition, thereby producing the encapsulant.
A method for manufacturing an organic EL light-emitting device. The ultraviolet curable resin composition is heated and then molded by an inkjet method.
A method for manufacturing the organic EL light-emitting device according to claim 6. The display device includes an organic EL element, and a sealant and an inorganic passivation layer that cover the organic EL element,
the encapsulant and the passivation layer overlap;
The sealing material is a cured product of the ultraviolet-curable resin composition according to any one of claims 1 to 5.
Organic EL light-emitting device.

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