KR20230104875A - UV-curable resin composition, light-emitting device, and method for manufacturing the light-emitting device - Google Patents

Abstract

In producing the encapsulant of the organic EL element by the inkjet method, it is difficult to create irregularities on the surface of the encapsulant, and it is difficult to generate outgas from the encapsulant, and an ultraviolet curable resin capable of increasing the adhesion between the encapsulant and the inorganic material. composition is provided. The ultraviolet curable resin composition is a compound (A) composed of at least one selected from the group consisting of N,N-dimethylacrylamide (A-1) and the like, and CH ₂ CXCO-O-(RO) _n -COCXCH ₂ The compound (B) represented by the formula and a photopolymerization initiator (D) containing an acylphosphine oxide compound are contained, and the viscosity at 25 ° C is 1 mPa s or more and 40 mPa s or less, and the viscosity at 40 ° C satisfies at least one of 1 mPa·s or more and 40 mPa·s or less.

Description

UV-curable resin composition, light-emitting device, and method for manufacturing the light-emitting device

The present disclosure relates to a UV curable resin composition, a light emitting device, and a method for manufacturing the light emitting device, and in detail, a UV curable resin composition that can be applied by an inkjet method, and a sealing material comprising a cured product of the UV curable resin composition. It relates to a light emitting device and a method for manufacturing the light emitting device using the ultraviolet curable resin composition.

Organic EL light-emitting devices are applied to lighting, displays, and the like, and are expected to spread in the future.

In an organic EL light emitting device, for example, an organic EL element is disposed on a support substrate, the organic EL element is covered with an inorganic layer called a passivation layer, and the passivation layer is further covered with a sealing material made of an organic resin.

It has been proposed to produce a sealing material in an organic EL light emitting device by an inkjet method. For example, in Patent Document 1, 75 to 95 wt.% of polyethylene glycol dimethacrylate monomer and the like, 4 to 10 wt.% of pentaerythritol tetraacrylate and the like, within the range of about 14 to about 18 cps at 22 ° C. Using an ink composition containing 1 to 15 wt.% of an electrodeposition modifier having a viscosity and a surface tension within the range of about 35 to about 39 dynes/cm at 22° C., manufacturing an encapsulant by an inkjet method is disclosed.

Japanese Patent Publication No. 2017-531049

If the sealing material is produced by applying the composition by the inkjet method, it is easy to produce the sealing material with high positional accuracy and it is easy to make the thickness of the sealing material thin.

However, according to the inventor's independent investigation, if the thickness of the encapsulant is reduced, irregularities are easily formed on the surface of the encapsulant because of the irregularities on the surface of the inorganic material serving as the base, making it difficult to smooth the surface of the encapsulant. do. Then, the light emitting performance of the organic EL light emitting device tends to decrease, and durability also tends to decrease.

In addition, in the encapsulant, in order to suppress the intrusion of moisture and prevent deterioration of the organic EL element, it is required that voids are unlikely to occur. It is also required that outgas is difficult to generate.

An object of the present disclosure is to manufacture a sealing material for sealing a light emitting element by an inkjet method, making it difficult to generate irregularities on the surface of the sealing material, making it difficult to generate outgas from the sealing material, and improving the adhesion between the sealing material and the inorganic material. It is to provide a light emitting device including an ultraviolet curable resin composition capable of increasing the height, a sealing material composed of a cured product of the ultraviolet curable resin composition, and a method for manufacturing the light emitting device using the ultraviolet curable resin composition.

An ultraviolet curable resin composition according to one aspect of the present disclosure,

a compound (A) comprising at least one member selected from the group consisting of N,N-dimethylacrylamide, N,N-diethylacrylamide and N-acryloylmorpholine;

A compound (B) represented by the following general formula (1);

CH ₂ =CXCO-O-(RO) _n -COCX=CH ₂ (1)

n is an integer of 1 or more and 3 or less, R is an alkylene group having 3 or more and 6 or less carbon atoms, provided that, when there are a plurality of R's in one molecule, each R is independently an alkylene group having 3 or more and 6 or less carbon atoms, and each X is independently hydrogen. atom or methyl group;

A photopolymerization initiator (D) containing an acylphosphine oxide compound;

The viscosity at 25°C satisfies at least one of 1 mPa·s or more and 40 mPa·s or less, and the viscosity at 40°C is 1 mPa·s or more and 40 mPa·s or less.

A light emitting device according to one aspect of the present disclosure includes a light emitting element and a sealing material for sealing the light emitting element, and the sealing material includes a cured product of the ultraviolet curable resin composition.

A method for manufacturing a light emitting device according to one aspect of the present disclosure is a method for manufacturing a light emitting device including a light emitting element and a sealing material for sealing the light emitting element, wherein the ultraviolet curable resin composition is applied by an inkjet method, and then the It includes producing the encapsulant by curing the ultraviolet curable resin composition by irradiating ultraviolet rays.

1 is a schematic cross-sectional view of an organic EL light emitting device in one embodiment of the present disclosure.
Fig. 2 is a schematic perspective view of a semi-finished product of the organic EL light emitting device described above.

Hereinafter, one embodiment of the present disclosure will be described. On the other hand, the embodiment described below is only one of various embodiments of the present disclosure. The following embodiments can be modified in various ways depending on the design, as long as the object of the present disclosure can be achieved.

The ultraviolet curable resin composition (hereinafter, also referred to as composition (X)) according to the present embodiment is used for sealing a light emitting element such as an organic EL element. Composition (X) contains compound (A), compound (B), and photopolymerization initiator (D), and has a viscosity of 1 mPa·s or more and 40 mPa·s or less at 25°C, and a viscosity at 40°C. At least one of 1 mPa·s or more and 40 mPa·s or less is satisfied. Composition (X) can be applied by an inkjet method due to the above configuration.

The compound (A) is composed of at least one selected from the group consisting of N,N-dimethylacrylamide, N,N-diethylacrylamide, and N-acryloylmorpholine.

A compound (B) is represented by the following formula.

CH ₂ =CXCO-O-(RO) _n -COCX=CH ₂ (1)

n is an integer of 1 or more and 3 or less. R is an alkylene group having 3 or more and 6 or less carbon atoms. However, when there are a plurality of R's in one molecule, R is each independently an alkylene group having 3 or more and 6 or less carbon atoms. X's are each independently a hydrogen atom or a methyl group.

The photopolymerization initiator (D) contains an acylphosphine oxide compound.

According to the present embodiment, when the encapsulant is produced on a substrate of an inorganic material, for example, when the encapsulant is produced by an inkjet method on a passivation layer made of an inorganic silicon compound or the like, even if the substrate has irregularities, the encapsulant It becomes difficult to form irregularities on the surface, and the smoothness of the sealing material can be improved. In addition, the encapsulant 5 can have high adhesion to the base of the inorganic material, and can make it difficult to generate outgas from the encapsulant 5 .

It is presumed that the above effects were realized for the following reasons. Since the above compound (A) can increase the adhesion between the composition (X) and the inorganic material, the composition (X) becomes easy to wet and spread on the inorganic material, thereby increasing the smoothness of the encapsulant 5. It is estimated. It is estimated that the compound (B) can improve the adhesion between the encapsulant 5 and the inorganic material. In addition, by the combination of compounds (A) and (B) and the acylphosphine oxide compound, the composition (X) can have good reactivity, thereby making it difficult for unreacted substances to remain in the encapsulant (5), For this reason, it is estimated that outgas becomes difficult to generate|occur|produce. In addition, the combination of the compound (A) and the compound (B) tends to realize the viscosity and surface tension of the composition (X) suitable for the inkjet method. Further, since the compounds (A) and (B) are relatively difficult to volatilize, the storage stability of the composition (X) is hardly impaired.

On the other hand, the above description is based on the conjecture of the inventor, and the present embodiment is not bound by the above description.

It is preferable that the hardened|cured material obtained by irradiating composition (X) with light and then heating has a glass transition temperature of 80 degreeC or more. In this case, the cured product can have good heat resistance. Therefore, when the hardened|cured material is subjected to the process accompanying a temperature rise, for example, hardened|cured material is hard to deteriorate. The glass transition temperature of the cured product is more preferably 90°C or higher, and still more preferably 100°C or higher.

It is preferable that the viscosity of composition (X) at 25 degreeC is 1 mPa*s or more and 40 mPa*s or less. In this case, it is possible to mold by applying the composition (X) at room temperature by a casting method, an inkjet method, or the like. The viscosity is more preferably 35 mPa·s or less, more preferably 30 mPa·s or less, particularly preferably 20 mPa·s or less, and most preferably 15 mPa·s or less. It is also preferable that this viscosity is 5 mPa*s or more, and it is more preferable in it being 8 mPa*s or more. For example, it is preferable that this viscosity is 8 mPa·s or more and 35 mPa·s or less.

It is also preferable that the composition (X) has a viscosity of 1 mPa·s or more and 40 mPa·s or less at 40°C. In this case, regardless of the viscosity of Composition (X) at room temperature, it is possible to lower the viscosity by slightly heating Composition (X). For this reason, when heated, it is easy to mold the composition (X) by a method such as a casting method, and it is also possible to mold the composition (X) by an inkjet method. In addition, since the composition (X) can be reduced in viscosity without significant heating, it is possible to make it difficult to change the composition of the composition (X) due to volatilization of components in the composition (X). The viscosity is more preferably 35 mPa·s or less, more preferably 30 mPa·s or less, particularly preferably 20 mPa·s or less, and most preferably 15 mPa·s or less. It is also preferable that this viscosity is 5 mPa*s or more, and it is more preferable in it being 8 mPa*s or more. For example, it is preferable that this viscosity is 8 mPa·s or more and 35 mPa·s or less.

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

The cured product of the composition (X) preferably has a total light transmittance of 90% or more when the thickness is 10 µm. In this case, when the cured product is applied to an optical component such as the encapsulant 5 in the organic EL light emitting device 1, the extraction efficiency of light passing through the optical component and emitted to the outside can be particularly improved. The light transmittance of such a cured product can also be achieved by the composition of Composition (X) described in detail below.

It is also preferable that the surface tension of composition (X) is 20 mN/cm or more and 40 mN/cm or less. In this case, when the composition (X) is applied by the inkjet method, the ejection stability is good, making it difficult to generate defective liquid droplets called satellites. The surface tension is more preferably 25 mN/cm or more and 40 mN/cm or less, and still more preferably 27 mN/cm or more and 38 mN/cm or less.

Hereinafter, this embodiment will be described in more detail.

1. Structure of organic EL light emitting device

First, the structure of an organic EL light emitting device 1 as an example of a light emitting device will be described. EL stands for electroluminescence. The organic EL light emitting device 1 includes an organic EL element 4 as a light emitting element and a sealing material 5 covering the organic EL element 4 . The organic EL element 4 is also called an organic light emitting diode. The encapsulant 5 may cover the organic EL element 4 in a state in direct contact with the organic EL element 4, or a state in which some layer is interposed between the encapsulant 5 and the organic EL element 4. may cover the organic EL element 4. The organic EL light emitting device 1 may be, for example, a lighting device or a display device (display).

The structure of the organic EL light emitting device 1 will be described. An organic EL light emitting device 1 includes an organic EL element 4 (organic light emitting diode), an encapsulant 5 covering the organic EL light emitting element 4, and a passivation layer 6. The encapsulant 5 and the passivation layer 6 overlap. On the other hand, EL is an abbreviation of electroluminescence.

An example of the structure of the organic EL light emitting device 1 will be described with reference to FIG. 1 . This organic EL light emitting device 1 is of a top emission type. The organic EL light emitting device 1 includes a support substrate 2, a transparent substrate 3 facing the support substrate 2 at a distance, and a barrier rib on the surface of the support substrate 2 facing the transparent substrate 3. (7) (black matrix) and the organic EL light emitting element 4, and the passivation layer 6 covering the organic EL light emitting element 4 and the sealing material 5 are provided.

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 light-transmitting material. The transparent substrate 3 is, for example, a glass substrate or a transparent resin substrate. The light emitting element 4 includes, for example, a pair of electrodes 41 and 43 and an organic light emitting layer 42 between the electrodes 41 and 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, and these layers are laminated in the above order.

The barrier rib 7 partitions the surface of the support substrate 2 . An organic EL element 4 is disposed between two adjacent barrier ribs 7 . The barrier rib 7 is produced, for example, by molding a photosensitive resin material by photolithography. The barrier ribs 7 are arranged, for example, in a stripe shape, that is, a plurality of barrier ribs 7 long in one direction are arranged at intervals in a direction orthogonal to the longitudinal direction. On the other hand, the manner in which the barrier ribs 7 are arranged is not limited only to the above, and the barrier ribs 7 may be arranged in a lattice form, for example. The height of the barrier rib 7 is, for example, 0.1 μm or more and 1.5 μm or less. In addition, the space|interval of the adjacent partition wall 7 is 30 micrometers or more and 150 micrometers or less, for example.

The organic EL element 4 includes, for example, a pair of electrodes 41 and 43 and an organic light emitting layer 42 between the electrodes 41 and 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, and these layers are laminated in the above order. The organic EL light emitting device 1 includes a plurality of organic light emitting elements 4, and the plurality of organic EL light emitting elements 4 form an array 9 (hereinafter referred to as an element array 9) on a support substrate 2. do) constitutes The element array 9 also includes connection wires 8 electrically connecting the electrodes 43 and electron transport layers 424 of adjacent organic EL light emitting elements 4 to each other. The connection wiring 8 is provided so as to cross the partition wall 7 .

The barrier rib 7 protrudes from the organic EL element 4 to the side opposite to the support substrate 2, and the protruding dimension of the barrier 7 from the organic EL element 4 is, for example, 0.1 μm or more and 1.5 μm. below

The passivation layer 6 is preferably made from silicon nitride or 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 organic EL element 4 by covering the element array 9 in a state of direct contact with the element array 9 . The first passivation layer 61 covers the surface of the organic EL element 4 and the top of the barrier rib 7 protruding beyond the organic EL element 4, so the surface of the first passivation layer 61 is the barrier rib. (7) has a concave-convex shape with convex portions according to the arrangement position (see FIG. 2).

The second passivation layer 62 is disposed at a position opposite to the element array 9 with respect to the first passivation layer 61, and is between the second passivation layer 62 and the first passivation layer 61. is spaced apart.

Between the first passivation layer 61 and the second passivation layer 62, an encapsulant 5 is filled. That is, the first passivation layer 61 is interposed between the organic EL element 4 and the sealing material 5 covering the organic EL element 4 .

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

The passivation layer 6 is preferably made from silicon nitride or silicon oxide, and is particularly preferably made from silicon nitride. In the example shown in FIG. 1 , the passivation layer 6 includes a first passivation layer 61 and a second passivation layer 62 . The first passivation layer 61 covers the light emitting element 4 by covering the element array 9 in a state of direct contact with the element array 9 . The second passivation layer 62 is disposed at a position opposite to the element array 9 with respect to the first passivation layer 61, and is between the second passivation layer 62 and the first passivation layer 61. is spaced apart. Between the first passivation layer 61 and the second passivation layer 62, an encapsulant 5 is filled. That is, the first passivation layer 61 is interposed between the light emitting element 4 and the sealing material 5 covering the light emitting element 4 .

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

2. UV Curable Resin Composition

The components of Composition (X) are described in detail. In the present specification, "(meth)acrylate" means "acrylate or methacrylate", and "(meth)acryloyl group" means "acryloyl group or methacryloyl group". In addition, di(meth)acrylate means that two (meth)acrylates may be the same or different.

Composition (X) contains a radically polymerizable compound, and the radically polymerizable compound contains at least a compound (A) and a compound (B).

As described above, the compound (A) is composed of at least one selected from the group consisting of N,N-dimethylacrylamide, N,N-diethylacrylamide and N-acryloylmorpholine.

The compound (A) can enhance the affinity between the sealing material 5 and the inorganic material by having a nitrogen atom. Therefore, it is thought that when the composition (X) is applied on the substrate of an inorganic material by the inkjet method, the composition (X) becomes easy to wet and spread on the substrate, thereby increasing the smoothness of the encapsulant 5.

In addition, the compound (A) has a low viscosity and low volatility. Therefore, the compound (A) can reduce the viscosity of the composition (X) so that it can be applied by an inkjet method, can also improve the storage stability of the composition (X), and furthermore outgassing from the encapsulant (5). can make it difficult to create. Furthermore, since the compound (A) has good reactivity, the composition (X) can be efficiently cured to produce the encapsulant 5.

It is preferable that the ratio of compound (A) is 20 mass % or more and 80 mass % or less with respect to the whole composition (X). When this ratio is 20% by mass or more, the smoothness of the sealing material 5 tends to be particularly high. In addition, when this ratio is 80% by mass or less, it becomes difficult for the composition (X) and the sealing material 5 to absorb moisture excessively, and for this reason, expansion of the sealing material 5 due to moisture causes the sealing material ( 5) is unlikely to be peeled off from the base. This ratio is more preferably 25% by mass or more and 70% by mass or less, and still more preferably 30% by mass or more and 50% by mass or less.

In a preferred aspect of the compound (A), at least N-acryloylmorpholine is included. It is preferable that the ratio of N-acryloylmorpholine is 5 mass % or more and 60 mass % or less with respect to the whole composition (X). When this ratio is 5% by mass or more, the photocurability of the sealing material 5 tends to be particularly high. In addition, when this ratio is 60% by mass or less, it becomes difficult to excessively absorb moisture in the composition (X) and the sealing material 5, and for this reason, the sealing material 5 expands due to moisture. It is difficult to peel off from the base. This ratio is preferably 20% by mass or more and 55% by mass or less, more preferably 25% by mass or more and 55% by mass or less, and still more preferably 30% by mass or more and 50% by mass or less.

In addition to containing N-acryloylmorpholine, the compound (A) preferably contains at least one of N,N-dimethylacrylamide and N,N-diethylacrylamide. In this case, the smoothness of the sealing material 5 tends to be higher. The ratio of the total amount of N,N-dimethylacrylamide and N,N-diethylacrylamide is preferably 5% by mass or more and 20% by mass or less with respect to the whole composition (X). When this ratio is 5% by mass or more, the smoothness of the sealing material 5 tends to be particularly high. In addition, when this ratio is 20% by mass or less, it becomes difficult to excessively absorb moisture in the composition (X) and the sealing material 5, and for this reason, the sealing material 5 is damaged by expansion of the sealing material 5 due to moisture. Peeling from the lower limb is unlikely to occur. This ratio is more preferably 5% by mass or more and 18% by mass or less, and still more preferably 8% by mass or more and 15% by mass or less.

Composition (X) may further contain N-substituted (meth)acrylamide (A-3) other than compound (A). N-substituted (meth)acrylamide (A-3) can also enhance the affinity between the composition (X) and the inorganic material. N-substituted (meth)acrylamide (A-3) is, for example, N,N-dimethylmethacrylamide, N,N-diethylmethacrylamide, N-methyl(meth)acrylamide, N-ethyl (meth)acrylamide, N-methyl-N-ethyl(meth)acrylamide, N-normalpropyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and N-hydroxyethyl(meth)acrylamide It contains at least 1 sort(s) selected from the group which consists of etc. It is preferable that the ratio of N-substituted (meth)acrylamide (A-3) in composition (X) is 10 mass % or less.

As described above, the compound (B) is represented by the following general formula (1).

CH ₂ =CXCO-O-(RO) _n -COCX=CH ₂ (1)

n is an integer of 1 or more and 3 or less. R is an alkylene group having 3 or more and 6 or less carbon atoms. However, when there are a plurality of R's in one molecule, R is each independently an alkylene group having 3 or more and 6 or less carbon atoms. X is each independently H or a methyl group.

Since the compound (B) has polarity, affinity between the sealing material 5 and the inorganic material can be improved. Therefore, it is thought that when the composition (X) is applied on the substrate of an inorganic material by the inkjet method, the composition (X) becomes easy to wet and spread on the substrate, thereby increasing the smoothness of the encapsulant 5. In addition, when the carbon number of R is 3 or more, it is possible to make it difficult for the encapsulant 5 to absorb excessive moisture, and for this reason, expansion of the encapsulant 5 due to absorption of moisture can be suppressed. Also by this, it is thought that the smoothness of the sealing material 5 becomes high.

Further, the compound (B) has a low viscosity and low volatility. Therefore, the compound (B) can reduce the viscosity of the composition (X) so that it can be applied by an inkjet method, can also improve the storage stability of the composition (X), and furthermore outgassing from the encapsulant (5). can make it difficult to create. Furthermore, since the compound (B) has good reactivity, the composition (X) can be cured efficiently to produce the encapsulant 5. Also, the compound (B) can increase the glass transition temperature of the encapsulant 5. For this reason, the heat resistance of the sealing material 5 can be improved.

Compound (B) is composed of dipropylene glycol diacrylate, tripropylene glycol diacrylate, neopentyl glycol diacrylate and 3-methyl-1,5-pentanediol diacrylate. It is preferable to contain at least 1 sort(s) selected from the group. In this case, the above effect of the compound (B) is particularly easy to obtain.

It is preferable that the ratio of compound (B) is 5 mass % or more and 75 mass % or less with respect to the whole composition (X). If this ratio is 5 mass % or more, outgas from the sealing material 5 can be reduced. Moreover, if this ratio is 75 mass % or less, there exists an advantage that the smoothness of the sealing material 5 becomes especially easy to increase. This ratio is more preferably 15% by mass or more and 65% by mass or less, and still more preferably 25% by mass or more and 60% by mass or less.

Composition (X) is a monofunctional (meth)acrylic compound (B2) and a bifunctional (meth)acrylic compound other than the above compound (A), N-substituted (meth)acrylamide (A-3) and compound (B). You may further contain at least one of the acrylic compounds (B3).

Monofunctional (meth)acrylate (B2) is, for example, an ester product of an alcohol having 2 to 30 carbon atoms and (meth)acrylic acid, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, tetrahydrofurfuryl Acrylates, mono(meth)acrylates of o-, m- or p-phenylphenol, mono(meth)acrylates of 3,3'-diphenyl-4,4'-dihydroxybiphenyl and nonylphenoxy It contains at least 1 sort(s) selected from the group which consists of polyethylene glycol (meth)acrylate etc.

The bifunctional (meth)acrylic compound (B3) is, for example, an esterified product of a polyhydric (preferably 2 to 8) alcohol having 2 to 30 carbon atoms and (meth)acrylic acid, or a polyhydric (preferably 2 to 8) carbon atoms. 2 to 8 valent) alkylene oxide (alkylene group having 2 to 4 carbon atoms) 1 to 30 mol adducts of alcohols and esters of (meth)acrylic acid (except for the above compound (B)), OH group content amount It contains at least one selected from the group consisting of terminal epoxy acrylates, di(meth)acrylates of ethylene oxide adducts of bisphenol A, di(meth)acrylates of ethylene oxide adducts of fluorene, and the like.

Composition (X) preferably further contains a compound (C) having three or more (meth)acryloyl groups in one molecule. The compound (C) can increase the reactivity of the composition (X) and also increase the glass transition temperature of the sealing material 5 to increase heat resistance.

Compound (C), for example, a trifunctional (meth)acryloyl compound having three (meth)acryloyl groups, a tetrafunctional (meth)acryloyl compound having four (meth)acryloyl groups, 5 Contains at least one selected from the group consisting of pentafunctional (meth)acryloyl compounds having two (meth)acryloyl groups and hexafunctional (meth)acryloyl compounds having six (meth)acryloyl groups do.

The trifunctional (meth)acryloyl compound is, for example, an esterified product of a trivalent or higher (preferably trivalent to octavalent) alcohol having 3 to 30 carbon atoms and (meth)acrylic acid [for example, tri(meth) of glycerin acrylate, tri(meth)acrylate of trimethylolpropane, tri(meth)acrylate of pentaerythritol], and alkyl of trivalent or higher (preferably trivalent to octavalent) alcohols having 3 to 30 carbon atoms. A group consisting of 1 to 30 mol adducts of ene oxide (alkylene group having 2 to 4 carbon atoms) and esters of (meth)acrylic acid [e.g., tri(meth)acrylate of ethylene oxide adduct of trimethylolpropane], etc. It contains at least 1 sort(s) selected from.

The tetrafunctional (meth)acryloyl compound is, for example, an ester product of a tetravalent or higher (preferably 4 to 8 valent) alcohol having 5 to 30 carbon atoms and (meth)acrylic acid [for example, tetra( meth)acrylate and tetra(meth)acrylate of dipentaerythritol]; and 1 to 30 mole adducts of alkylene oxides (alkylene groups having 2 to 4 carbon atoms) of tetravalent or higher (preferably 4 to 8 valent) alcohols having 5 to 30 carbon atoms and esters of (meth)acrylic acid [eg For example, tetra(meth)acrylates of ethylene oxide adducts of pentaerythritol and tetra(meth)acrylates of ethylene oxide adducts of dipentaerythritol].

The pentafunctional (meth)acryloyl compound and the hexafunctional (meth)acryloyl compound are, for example, an ester product of a tetravalent or higher (preferably 4 to 8 valent) alcohol having 5 to 30 carbon atoms and (meth)acrylic acid. [For example, dipentaerythritol penta(meth)acrylate and dipentaerythritol hexa(meth)acrylate]; and 1 to 30 mole adducts of alkylene oxides (alkylene groups having 2 to 4 carbon atoms) of tetravalent or higher (preferably 4 to 8 valent) alcohols having 5 to 30 carbon atoms and esters of (meth)acrylic acid [eg For example, penta(meth)acrylate of ethylene oxide adduct of dipentaerythritol, penta(meth)acrylate of propylene oxide adduct of dipentaerythritol] and the like.

The compound (C) preferably contains at least one of a trifunctional (meth)acryloyl compound and a tetrafunctional (meth)acryloyl compound, tri(meth)acrylate of trimethylolpropane, and pentaerythate. It is more preferable to contain at least 1 sort(s) selected from the group which consists of tri(meth)acrylate of ritol, and tetra(meth)acrylate of pentaerythritol.

It is preferable that the ratio of compound (C) is more than 0 mass % and 10 mass % or less with respect to the whole composition (X). When this ratio is 10% by mass or less, an increase in the viscosity of the composition (X) is suppressed. This ratio is more preferably 8% by mass or less, and still more preferably 5% by mass or less.

As described above, the composition (X) contains a photopolymerization initiator (D), and the photopolymerization initiator (D) contains an acylphosphine oxide compound. For this reason, as described above, it is possible to make it difficult to generate outgas from the sealing material 5 . Acylphosphine oxide compounds include, for example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide , diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide.

The photopolymerization initiator (D) may further contain compounds other than acylphosphine oxide compounds, such as benzoin compounds, acetophenone compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, α- You may further contain at least 1 sort(s) chosen from the group which consists of an aminoalkyl phenone compound, an oxime ester compound, etc. Benzoin compounds include, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, 2-hydroxy-2-methyl-1-phenylpropan-1-one and It contains at least 1 sort(s) selected from the group which consists of 1-hydroxycyclohexyl phenyl ketone etc. The acetophenone compound is, for example, acetophenone, 2,2-diethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 2- Hydroxy-2-methyl-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholy It contains at least 1 sort(s) selected from the group which consists of nopropan-1-one etc. The anthraquinone compound contains at least one selected from the group consisting of, for example, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-chloroanthraquinone, and 2-amylanthraquinone. The thioxanthone compound contains at least one selected from the group consisting of, for example, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, and 2-chlorothioxanthone. A ketal compound contains at least 1 sort(s) chosen from the group which consists of acetophenone dimethyl ketal, a benzyl dimethyl ketal, etc., for example. The benzophenone compound contains at least one selected from the group consisting of, for example, benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 4,4'-bismethylaminobenzophenone. The α-aminoalkylphenone compounds are, for example, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopro-butanone-1 and 2-(dimethylamino)-2-[( 4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone] and the like. The oxime ester compound is 1,2-octanedione, 1-[4-(phenylthio)-, 2-(O-benzoyloxime)] and ethanone-1-[9-ethyl-6-(2 -Methylbenzoyl) -9H-carbazol-3-yl] -1-(O-acetyloxime) and the like.

It is preferable that the ratio of the acylphosphine oxide compound is 5 mass % or more and 20 mass % or less with respect to the whole composition (X). When this ratio is 5% by mass or more, the reactivity of the composition (X) can be particularly enhanced, and generation of outgas from the sealing material 5 can be particularly suppressed. When this ratio is 20% by mass or less, it is easy to keep the viscosity of Composition (X) low. This ratio is more preferably 6% by mass or more and 19% by mass or less, and still more preferably 7% by mass or more and 18% by mass or less.

Composition (X) preferably contains a surfactant (E). In this case, the smoothness of the sealing material 5 is further improved.

The surfactant (E) preferably contains at least one of a silicone surfactant and a fluorochemical surfactant. In this case, the composition (X) becomes easier to wet and spread on the inorganic material, and for this reason, the smoothness of the encapsulant 5 is more likely to be higher. In particular, when the surfactant (E) contains a silicone surfactant, the composition (X) spreads easily over the base and convex portions. That is, for example, when the substrate of inorganic material has stripe-shaped convex portions as shown in Fig. 2, when the composition (X) is applied on the substrate, the composition (X) wets the substrate in a direction perpendicular to the longitudinal direction of the convex portions. It becomes easier to spread. For this reason, the smoothness of the sealing material 5 tends to become especially high.

On the other hand, surfactant (E) may contain components other than a silicone type surfactant and a fluorochemical surfactant.

It is preferable that the ratio of surfactant (E) is 0.02 mass % or more and 1.0 mass % or less with respect to the whole composition (X). Since wettability with respect to an inorganic material of composition (X) becomes especially high when this ratio is 0.02 mass % or more, the smoothness of the sealing material 5 becomes especially high easily. Moreover, if this ratio is 1 mass % or less, since the coating film produced by apply|coating composition (X) on a base|substrate becomes difficult to bubble, the smoothness of the sealing material 5 will increase easily.

Composition (X) may contain various additives in order to express various functionalities as needed. Specifically, the additive contains at least one selected from the group consisting of a light stabilizer, a surface treatment agent, an antioxidant, an antiaging agent, a crosslinking accelerator, a polymerization inhibitor, a plasticizer, an antiseptic agent, a pH adjuster, an antifoaming agent, and a moisturizing agent. can do. The ratio of the total amount of the additive is, for example, 1.0% by mass or less, 0.5% by mass or less, or 0.4% by mass or less with respect to the total amount of the composition (X). In addition, this ratio is 0.05 mass % or more, for example.

Composition (X) may further contain a moisture absorbent (F). When the composition (X) contains the moisture absorbent (F), the cured product can have excellent hygroscopicity. It is preferable that the average particle diameter of the moisture absorbent (F) is 200 nm or less. In this case, despite containing the moisture absorbent (F), the cured product can have high transparency. Further, when the composition (X) is applied by an inkjet method, when the average particle diameter of the moisture absorbent (F) is 200 nm or less, the composition (X) is less likely to clog the nozzle. Furthermore, when the average particle diameter of the moisture absorbent (F) is 200 nm or less, the moisture absorbent (F) hardly damages the smoothness of the surface of the sealing material 5. Therefore, the surface of the sealing material 5 can have good smoothness.

The moisture absorbent (F) is preferably an inorganic particle having hygroscopicity, and contains, for example, 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 desirable It is particularly preferred that the moisture absorbent (F) contains zeolite particles.

It is preferable that the average particle diameter of the moisture absorbent (F) is 10 nm or more and 200 nm or less. If this average particle diameter is 200 nm or less, the sealing material 5 can have especially high transparency. Moreover, favorable hygroscopicity of a moisture absorbent (F) can be maintained as this average particle diameter is 10 nm or more. On the other hand, this average particle diameter is the median diameter calculated from the measurement result by the dynamic light scattering method, that is, the cumulative 50% diameter (D50). On the other hand, as a measuring device, the Nanotrac Wave series of Microtracbell Co., Ltd. can be used.

The average particle diameter of the moisture absorbent (F) is more preferably 150 nm or less, further preferably 100 nm or less, and particularly preferably 70 nm or less. Moreover, it is preferable that the average particle diameter of a moisture absorbent (F) is 20 nm or more, and it is more preferable in it being 50 nm or more. In this case, the sealing material 5 can have particularly good transparency and hygroscopicity.

It is also preferable that the cumulative 90% diameter (D90) of the moisture absorbent (F) is 100 nm or less. In this case, the cured product can have particularly high transparency.

The ratio of the moisture absorbent (F) to the total amount of the composition (X) is preferably 1% by mass or more and 20% by mass or less. When the ratio of the moisture absorbent (F) is 1% by mass or more, the cured product can have particularly high hygroscopicity. In addition, when the ratio of the moisture absorbent (F) is 20% by mass or less, the viscosity of the composition (X) can be particularly reduced, and the composition (X) may have a sufficiently low viscosity to the extent that it can be applied by the inkjet method. The ratio of the moisture absorbent (F) is more preferably 3% by mass or more, and particularly preferably 5% by mass or more. Moreover, the ratio of the moisture absorbent (F) is more preferably 15% by mass or less, and particularly preferably 13% by mass or less.

Composition (X) may further contain inorganic fillers other than the moisture absorbent (F). In particular, composition (X) preferably contains nano-sized high refractive index particles. Examples of high refractive index particles include zirconia particles. When the composition (X) contains the high refractive index particles, the cured product can be made high in refractive index while maintaining good transparency of the cured product. Therefore, the extraction efficiency of the light emitted to the outside through the sealing material 5 in the organic EL light emitting device 1 can be improved. The average particle diameter of the high refractive index particles is preferably in the range of 5 to 30 nm, and more preferably in the range of 10 to 20 nm.

The ratio of the high refractive index particles in the composition (X) is appropriately designed so that the encapsulant 5 has a desired refractive index. Particularly, the high refractive index particles are preferably contained in the composition (X) such that the refractive index of the cured product is in the range of 1.45 or more and less than 1.55. In this case, the light extraction efficiency of the organic EL light emitting device 1 is particularly improved.

When composition (X) contains a moisture absorbent (F), it is preferable that composition (X) further contains a dispersing agent (G). In this case, the dispersant (G) can improve the dispersibility of the moisture absorbent (F) in the composition (X). For this reason, it is difficult for composition (X) to increase viscosity and decrease storage stability due to moisture absorbent (F).

On the other hand, the dispersant (G) is a surfactant that can be adsorbed to particles. The dispersant (G) has an adsorbent (generally referred to as an anchor) capable of being adsorbed to the particles, and a molecular backbone (generally referred to as a tail) attached to the particles as the adsorbent is adsorbed onto the particles. The dispersant (G) is composed of, for example, an acrylic dispersant whose tail is an acrylic molecular chain, a urethane dispersant whose tail is a urethane molecular chain, and a polyester dispersant whose tail is a polyester molecular chain. It contains at least 1 sort(s) of component selected from the group. The adsorption group contains, for example, at least one of a basic polar functional group and an acidic polar functional group. The basic polar functional group includes, for example, at least one group selected from the group consisting of an amino group, an imino group, an amide group, an imide group, and a nitrogen-containing heterocyclic group. The acidic polar functional group includes, for example, at least one group selected from the group consisting of a carboxyl group and a phosphoric acid group. The dispersing agent (G) is, for example, at least one compound selected from the group consisting of Solspurs series manufactured by Nippon Lubrizol Co., Ltd., DISPERBYK series manufactured by Big Chemie Japan Co., Ltd., and Ajisper series manufactured by Ajinomoto Fine Techno Co., Ltd. may contain

When the composition (X) contains the moisture absorbent (F), the amount of the dispersant (G) relative to 100 parts by mass of the moisture absorbent (F) is preferably 5 parts by mass or more and 60 parts by mass or less. When the amount of the dispersing agent (G) is 5 parts by mass or more, the function of the dispersing agent (G) can be effectively expressed, and when the amount is 60 parts by mass or less, the molecules of the dispersing agent (G) in the sealing material 5 are released. Impairment of the adhesion between the encapsulant 5 and the member made of an inorganic material can be suppressed. The amount of the dispersant (G) is more preferably 15 parts by mass or more, more preferably 50 parts by mass or less, still more preferably 40 parts by mass or less, and particularly preferably 30 parts by mass or less.

It is preferable that composition (X) does not contain a solvent, or content of a solvent is 1 mass % or less. In this case, when producing a cured product from the composition (X), there is no need to volatilize the solvent by drying the composition (X). In addition, the storage stability of the composition (X) is further increased. The content of the solvent is more preferably 0.5% by mass or less, more preferably 0.3% by mass or less, and particularly preferably 0.1% by mass or less. It is particularly preferred that the composition (X) does not contain a solvent or contains only a solvent that is unavoidably incorporated.

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

The moisture content of Composition (X) is preferably 100 ppm or less, more preferably 70 ppm or less, and particularly preferably 50 ppm or less from the viewpoint of reducing outgassing.

3. Manufacturing method of sealing material and manufacturing method of 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 produce the sealing material 5 by forming a coating film by molding the composition (X) by an inkjet method, irradiating the composition (X) with ultraviolet rays to the coating film, and then heating it. In this embodiment, it is possible to apply and shape the composition (X) by an inkjet method.

In applying the composition (X) by the inkjet method, when the composition (X) has a sufficiently low viscosity at room temperature, for example, when the viscosity at 25°C is 30 mPa s or less, particularly 15 mPa s or less, It can be molded by applying Composition (X) by an inkjet method without heating.

When the composition (X) has a property of reducing the viscosity by heating, the composition (X) may be applied by an inkjet method after heating the composition (X), and then molded. When the viscosity of the composition (X) at 40°C is 30 mPa·s or less, particularly 15 mPa·s or less, the viscosity of the composition (X) can be reduced only by slightly heating the composition (X). can be discharged by law. The heating temperature of the composition (X) is, for example, 20°C or higher and 50°C or lower.

In curing the coating film obtained by molding the composition (X) by irradiation with light, the light applied to the coating film is, for example, ultraviolet rays. An ultraviolet ray means a light ray whose wavelength is in the range of 200 nm or more and 410 nm or less. It is preferable that the wavelength of the light irradiated to the coating film is within the range of 350 nm or more and 410 nm or less, and more preferably 385 nm or more and 405 nm or less. As one of the representative examples of the light applied to the coating film, light having a wavelength of 395 nm is exemplified. On the other hand, the wavelength of light irradiated to the coating film is not limited to the above description as long as the coating film is cured.

It is preferable that the irradiation intensity of the light irradiated to the coating film is 20 mW/m ² or more and 20 W/cm ² or less. On the other hand, the irradiation intensity of light is not limited to the above description as long as it can cure the coating film.

In irradiating the coating film with light, the shape of the portion to which the light is irradiated may be an area shape having a certain area or a line shape. In the case of a linear type, light can be irradiated to the entire coating film by moving the coating film relative to the light source or by moving the light source relative to the coating film. In this case, it is easy to adjust the time period during which the coating film is irradiated with light, and by adjusting this period of time, it is easy to adjust the amount of integrated light.

In this embodiment, the coating film may be cured by irradiating light in the air. In the present embodiment, since the composition (X) can have good reactivity, the reaction of the composition (X) can be advanced and cured even in the air. In particular, it is preferable to cure the coating film by irradiating light in a dry air. In this case, it can suppress that the composition (X) and the sealing material (5) absorb moisture.

It is preferable that the heating temperature in the case of further heating the hardened coating film is 90 degreeC or more. In this case, the curing of the coating film is further advanced, and the coefficient of linear expansion of the encapsulant 5 is easily lowered.

More specifically, for example, first, the support substrate 2 is prepared. A barrier 7 (black matrix) is formed on one surface of the support substrate 2 by a photolithography method using, for example, a photosensitive resin material. Subsequently, a plurality of organic EL elements 4 are provided on one surface of the support substrate 2 . The organic EL element 4 can be produced by an appropriate method such as a vapor deposition method or a coating method. In particular, it is preferable to manufacture the organic EL element 4 by a coating method such as an inkjet method. In this way, the element array 9 is fabricated on the support substrate 2 .

Next, a first passivation layer 61 is provided so as to cover the organic EL element 4 and the barrier rib 7 . The first passivation layer 61 can be produced by, for example, a vapor deposition method such as a plasma CVD method. As shown in FIG. 2, the surface of the 1st passivation layer 61 has a concavo-convex shape with a convex part corresponding to the arrangement|positioning position of the partition wall 7 (refer FIG. 2).

Next, on the 1st passivation layer 61, composition (X) is apply|coated by the inkjet method, and a coating film is produced. If the inkjet method is applied to both the formation of the organic EL element 4 and the application of the composition (X), the production efficiency of the organic EL light-emitting device 1 can be particularly improved. Subsequently, the coating film is cured by irradiation with ultraviolet rays, and the sealing material 5 is produced. In this embodiment, as described above, it is easy to smooth the surface of the sealing material 5.

The thickness of the sealing material 5 is 2 micrometers or more and 50 micrometers or less, for example. It is also preferable that the thickness of the sealing material 5 is 2 μm or more and 30 μm or less, and more preferably 2 μm or more and 15 μm or less. As described above, in the present embodiment, it is easy to form small droplets of the composition (X) at high density by the inkjet method, so it is easy to realize a thin encapsulant 5 of 2 μm or more and 15 μm or less. When the encapsulant 5 is thinned in this way, tensile stress and compressive stress are less likely to occur in the encapsulant 5 in the organic EL light emitting device 1 . Therefore, it becomes easy to realize the flexible organic EL light emitting device 1. In this embodiment, even if the sealing material 5 is thinned, as described above, it is easy to smooth the surface of the sealing material 5.

Next, a second passivation layer 62 is provided on the encapsulant 5 . The second passivation layer 62 can be produced by, for example, a deposition method such as a plasma CVD method. In this embodiment, since it is easy to smooth the sealing material 5 as mentioned above, it is hard for the 2nd passivation layer 62 to produce the defect resulting from the unevenness of the sealing material 5 which is a base material.

Next, on one side of the support substrate 2, after providing an ultraviolet curable resin material so as to cover the second passivation layer 62, the transparent substrate 3 is overlaid on this resin material. The transparent substrate 3 is, for example, a glass substrate or a transparent resin substrate. Next, ultraviolet rays are irradiated toward the transparent substrate 3 from the outside. The ultraviolet rays pass through the transparent substrate 3 and reach the ultraviolet curable resin material. As a result, the ultraviolet curable resin material is cured, and the second sealing material 52 is produced.

Example

Hereinafter, specific embodiments of the present disclosure are presented. However, the present disclosure is not limited only to the following examples.

1. Preparation of the composition

Compositions of Examples and Comparative Examples were prepared by mixing the components shown in the column of "Composition" in the table below.

In addition, the detail of the component shown in a table|surface is as follows.

- N,N-dimethylacrylamide: Product: DMAA, manufactured by KJ Chemicals Co., Ltd.

- N-acryloylmorpholine: Trade name ACMO, manufactured by KJ Chemicals Co., Ltd.

- N,N-diethyl acrylamide: trade name DEAA, manufactured by KJ Chemicals Co., Ltd.

- N-hydroxyethyl acrylamide: Trade name HEAA, manufactured by KJ Chemicals Co., Ltd.

- Dipropylene glycol diacrylate: Trade name NK Ester APG-100, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.

- Tripropylene glycol diacrylate: Trade name NK Ester APG-200, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.

- Neopentyl glycol diacrylate: Trade name Light Acrylate NP-A, manufactured by Kyoeisha Chemical Co., Ltd.

- 3-methyl-1,5-pentanediol diacrylate: Trade name light acrylate MPD-A, manufactured by Kyoeisha Chemical Co., Ltd.

- Diethylene glycol diacrylate: Trade name Pancryl FA-222A, manufactured by Hitachi Chemical Co., Ltd.

- Polyethylene glycol diacrylate: Trade name NK Ester A-400, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.

- Polypropylene glycol diacrylate: Trade name NK Ester APG-400, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.

- Pentaerythritol triacrylate: Trade name Light Acrylate PE-3A, manufactured by Kyoeisha Chemical Co., Ltd.

- Dipentaerythritol hexaacrylate, trade name Neomer DA-600, manufactured by Sanyo Chemical Industry Co., Ltd.

- Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, trade name Omnirad 819 from IGM Resin.

- Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, trade name Omnirad TPO H, manufactured by IGM Resin.

- 2-Methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one: trade name Omnirad 907 manufactured by IGM Resin.

- Anthracure UVS-581: manufactured by Kawasaki Chemical Industry Co., Ltd.

- Silicone surfactant 1: Trade name TEGO Twin 4000, manufactured by Evonik.

- Silicone surfactant 2: Trade name TEGO Twin 4200, manufactured by Evonik.

- Fluorine-based surfactant: trade name Suplon S-386, manufactured by AGC Seimi Chemical Co., Ltd.

2. Assessment test

For Examples and Comparative Examples, the following evaluation test was conducted. The results are shown in a table.

(1) Transmittance

After the composition was applied on a smooth table, light was applied to the composition in dry air using an LED-UV irradiator manufactured by CISS Co., Ltd. under conditions of a peak wavelength of 395 nm, an output of 1 W/cm ² , and a cumulative light amount of 1.5 J/cm ² . It was photocured by irradiation. In this way, a film having a thickness of 15 μm was produced. The light transmittance of this film at a wavelength of 430 nm was measured. In the measurement, a spectrophotometer (U-4100 manufactured by Hitachi, Ltd.) was used.

(2) Viscosity

The viscosity of the composition was measured using an E-type viscometer (TVE-35 manufactured by Toki Sangyo Co., Ltd.) under conditions of a rotational speed of 20 rpm and a temperature of 25°C.

(3) surface tension

The surface tension of the composition was measured by the Wilhelmy method. In the measurement, it measured at the measurement temperature of 25 degreeC using the surface tensiometer (Kyowa Interface Chemical Co., Ltd. product automatic surface tension meter DY-300).

(4) Moisture content

The moisture content of the composition was measured using a trace moisture measuring device (AQ-300 manufactured by Hiranuma Sangyo Co., Ltd.).

(5) Inkjet property (initial)

The composition was placed in a cartridge of an inkjet printer (Model: MH2420 manufactured by Ricoh Corporation), and after confirming that the composition in the cartridge could be ejected from a nozzle in the inkjet printer, the composition was ejected from the nozzle to continuously print a test pattern. A state in which droplets of the composition were ejected from the nozzle was photographed with a high-speed camera, and it was confirmed whether or not the droplets were separated and satellites were generated. As a result, "A" is the case where the droplet is not separated, and "B" is the case where the satellite is integrated with the original droplet and becomes one droplet again after the satellite is separated from the original droplet. A case where the satellites were not integrated while being separated was evaluated as "C".

(6) Inkjet property (after 24 hours)

The composition was treated for 24 hours while being circulated in an inkjet apparatus and stored. The circulation rate was 1 ml/min. Subsequently, inkjet properties were evaluated by the same method as in the case of "(4) inkjet properties (initial stage)" described above.

(7) smoothness

A prebaked film was produced by applying a photosensitive polyimide resin (manufactured by Toray, product name: Photoneece DL-1000) on a glass substrate and then heating at 120°C for 3 minutes using a hot plate. It was 2 micrometers when the thickness of the prebaking film was measured with the spectrophotometer (U-4100 of Hitachi High-Technologies). After this prebaked film was exposed through a port mark, it was developed by exposing to a developing solution (a 2.38% by mass solution of tetramethylammonium hydroxide) for 60 seconds, and further heated at 250°C for 60 minutes in a clean oven. Thus, barrier ribs (black matrix) having a height of 0.5 μm and arranged in a lattice shape were fabricated on the glass substrate. The plan view dimension of the opening surrounded by the barrier rib is 70 μm × 250 μm.

A silicon nitride film having a thickness of 500 nm was formed on the entire surface of the glass substrate on which the barrier ribs were formed so as to cover the barrier ribs.

The composition was put into a cartridge of an inkjet printer (Material Printer MP2831, manufactured by Fujifilm), and after confirming that the composition in the cartridge could be ejected from a nozzle in the inkjet printer, droplets of the composition were ejected from the nozzle under conditions of 600 dpi. , a coating film with a maximum thickness of 5 μm was produced.

5 minutes after the formation of the coating film, the coating film was irradiated with light in a dry atmosphere using an LED-UV irradiator manufactured by CISS Co., Ltd. under the conditions of a peak wavelength of 395 nm, an output of 100 mW/cm ² , and a cumulative light amount of 1500 mJ/cm ^{2 .} It was photocured to produce an encapsulant.

The coating film was observed immediately before irradiation with light 5 minutes after the production of the coating film, and the case where the surface of the coating film was flat was evaluated as "A".

When not evaluated as "A", in the above, after producing a coating film and leaving it to stand for 20 minutes without irradiating light, the coating film was observed. As a result, when the surface of the coating film was flat, it was evaluated as "B", and when the surface of the coating film was curved, it was evaluated as "C".

(8) Outgas evaluation

The outgas in the case of heating the cured product of the composition was sampled by the head space method and measured by gas chromatography. Specifically, first, 100 mg of the composition was placed in a vial for a head space having a volume of 22 mL. Subsequently, the composition was irradiated with light in an air atmosphere using an LED-UV irradiator manufactured by CISS Co., Ltd. under conditions of a peak wavelength of 395 nm and about 100 mW/cm ² to cure the composition, and then the vial was sealed. Subsequently, after heating the composition at 80°C for 30 minutes, the gaseous portion in the vial was subjected to gas chromatography and analyzed. As a result, the concentration of outgas generated from the composition was specified based on the peak area of the obtained gas chromatogram. The concentration of outgas is the volume fraction of the outgas in the gas phase of the vial with respect to the volume (22 mL) of the vial.

On the other hand, the concentration of outgas was specified using toluene as a reference substance. Specifically, two standard samples with toluene concentrations of 1000 ppm and 100 ppm were prepared by volatilizing toluene in a vial. Each reference sample was subjected to gas chromatography and analyzed. From the peak areas of the two chromatograms thus obtained, the relationship between the peak area and the concentration was defined, and based on this result, the mass ratio of the outgas concentration was specified and evaluated according to the following criteria. On the other hand, in order to say that outgas is difficult to generate, this result is preferably 200 ppm or less, more preferably 100 ppm or less, further preferably 70 ppm or less, and particularly preferably 50 ppm or less.

A: 50 ppm or less.

B: More than 50 ppm and 70 ppm or less.

C: greater than 100 ppm.

(9) Adhesion

A SiN film having a refractive index of 1.83 and a thickness of 0.5 µm was formed on the surface by plasma CVD. The composition was applied to the surface of a SiN film in a piece of quartz glass (dimensions: 50 mm × 25 mm × 1 mm) to form a coating film having a thickness of 50 µm. On this coating film, another piece of quartz glass was superimposed so that the size of the area in contact with both was 12.5 mm x 25 mm. The composition was photocured by irradiation with ultraviolet rays in an air atmosphere using an LED-UV irradiator manufactured by CISS Co., Ltd. under conditions of a peak wavelength of 395 nm, an irradiation intensity of 5 W/cm ² and a cumulative light amount of 3000 mJ/cm ² .

Next, the adhesion strength between the two pieces of quartz glass was measured by conducting a tensile shear test (pulling speed: 5 mm/min) according to JIS K6850. The results were evaluated according to the following criteria.

A: 15 N/mm ² or more.

B: 5 N/mm ² or more and less than 15 N/mm ² .

C: Less than 5 N/mm ² .

From the results in the table, the compositions of Examples 1 to 27 have low initial viscosities, and are excellent in inkjet properties and smoothness. In addition, the cured products obtained by curing the compositions of Examples 1 to 27 hardly generate outgas and have excellent adhesion to inorganic materials. On the other hand, Comparative Example 1 containing no compound (A) has poor wettability with inorganic materials, poor smoothness, and poor adhesion. In addition, the composition of Comparative Example 2 containing only N-substituted (meth)acrylamide (A-3) other than compound (A) has poor smoothness and poor adhesion, as in Comparative Example 1. Further, Comparative Example 2 has a high viscosity and poor inkjet properties, so it is not suitable for the inkjet method. In the composition of Comparative Example 3 containing no bifunctional (meth)acrylic compound, outgassing is likely to occur from the encapsulant. In Comparative Examples 4 to 6 containing the bifunctional (meth)acrylic compound (B3) but not containing the compound (B), the adhesion of the sealing material is poor. In Comparative Example 7 not containing an acylphosphine oxide-based initiator, outgassing is likely to occur from the encapsulant.

Claims (12)

a compound (A) comprising at least one member selected from the group consisting of N,N-dimethylacrylamide, N,N-diethylacrylamide and N-acryloylmorpholine;
A compound (B) represented by the following general formula (1);
CH ₂ =CXCO-O-(RO) _n -COCX=CH ₂ (1)
n is an integer of 1 or more and 3 or less, R is an alkylene group having 3 or more and 6 or less carbon atoms, provided that, when there are a plurality of R's in one molecule, each R is independently an alkylene group having 3 or more and 6 or less carbon atoms, and each X is independently hydrogen. atom or methyl group;
A photopolymerization initiator (D) containing an acylphosphine oxide compound;
The viscosity at 25 ° C satisfies at least one of 1 mPa s or more and 40 mPa s or less, and the viscosity at 40 ° C is 1 mPa s or more and 40 mPa s or less.
An ultraviolet curable resin composition. According to claim 1,
The compound (B) is dipropylene glycol diacrylate, tripropylene glycol diacrylate, neopentyl glycol diacrylate and 3-methyl-1,5-pentanediol diacrylate. Containing at least one selected from the group consisting of
An ultraviolet curable resin composition. According to claim 1 or 2,
The ultraviolet curable resin composition in which the said compound (A) contains at least the said N,N-acryloylmorpholine. According to claim 3,
The compound (A) contains the N,N-acryloylmorpholine and at least one of the N,N-dimethylacrylamide and the N,N-diethylacrylamide,
An ultraviolet curable resin composition. According to claim 4,
The ratio of the total amount of the N, N-dimethylacrylamide and the N, N-diethylacrylamide is 5% by mass or more and 20% by mass or less with respect to the entire ultraviolet curable resin composition,
An ultraviolet curable resin composition. According to any one of claims 3 to 5,
The ratio of the N-acryloylmorpholine is 5% by mass or more and 60% by mass or less with respect to the entirety of the ultraviolet curable resin composition,
An ultraviolet curable resin composition. According to any one of claims 1 to 6,
Further containing a compound (C) having three or more (meth)acryloyl groups in one molecule,
An ultraviolet curable resin composition. According to any one of claims 1 to 7,
Further containing a surfactant (E),
An ultraviolet curable resin composition. According to claim 8,
The surfactant (E) contains at least one of a silicone surfactant and a fluorochemical surfactant,
An ultraviolet curable resin composition. According to any one of claims 1 to 9,
The moisture content of the ultraviolet curable resin composition is 100 ppm or less,
An ultraviolet curable resin composition. A light emitting element and a sealing material for sealing the light emitting element, wherein the sealing material comprises a cured product of the ultraviolet curable resin composition according to any one of claims 1 to 10,
light emitting device. A method for manufacturing a light emitting device comprising a light emitting element and a sealing material for sealing the light emitting element,
After applying the ultraviolet curable resin composition according to any one of claims 1 to 10 by an inkjet method, the ultraviolet curable resin composition is cured by irradiation with ultraviolet rays to produce the sealing material,
A method for manufacturing a light emitting device.

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