JP2000086746A - Ultraviolet-curing type resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ultraviolet-curing type resin composition capable of realizing ultrahigh moisture resistance in airtight sealing of an element having low resistance to heat such as a photoelectric element or a light emitting element. SOLUTION: This ultraviolet-curing type resin composition is obtained by compounding (a) an epoxy compound having two or more epoxy groups in one molecule with (b) a photocationic curing initiator and (c) at least one inorganic filler selected from the group of a platy inorganic filler and a scaly inorganic filler as essential components. The amount of the compounded inorganic filler (c) is >=20 wt.% in the resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention protects a hermetically sealed photoelectric device, light-emitting device (hereinafter referred to as "device") and the like from an external environment, and can maintain its reliability at an extremely high level. And a UV-curable resin composition.

[0002]

2. Description of the Related Art Since elements such as photoelectric elements and light emitting elements are greatly affected by changes in ambient temperature and humidity, etc.
It is well known that the device is used while being protected from the external environment by hermetic sealing.

In this hermetic sealing, glass, ceramic,
After mounting the element in a hollow package made of resin, etc., the upper part is fixed with a transparent material such as quartz glass, ceramic plate, etc. lid, using an adhesive, and the method of sealing is increasing are doing. Conventionally, a thermosetting epoxy resin was generally used for the adhesive, but in recent years, the number of elements that are weak to heat has increased, and the number of cases where a thermosetting resin cannot be used has increased. . Turning now to the current situation of ultraviolet curable resin adhesives, see JP-A-7-109.
As disclosed in Japanese Patent Application Laid-Open No. 333, there is an example of an epoxy resin-based ultraviolet curable resin, but good performance has not always been realized in the above-mentioned application of hermetic sealing of the element.

[0004]

SUMMARY OF THE INVENTION The present invention has been made as a result of intensive studies in order to solve such problems, and can realize extremely high moisture resistance in hermetic sealing of heat-sensitive elements. An object is to provide an ultraviolet-curable resin composition.

[0005]

That is, the present invention provides an epoxy compound (a) having two or more epoxy groups in one molecule, a cationic photocuring initiator (b), and a plate-like inorganic filler and scale. At least one inorganic filler (c) selected from the group consisting of the inorganic fillers in the form of an essential component,
The ultraviolet curable resin composition is characterized in that the resin composition contains 20% by weight or more of the inorganic filler (c).

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One of the important reliability tests of a device is a moisture resistance test. In this moisture resistance test, a hollow package enclosing the element is treated for a long time under high-temperature and high-humidity conditions, and an external appearance defect such as characteristic fluctuation or accumulation of moisture inside the package is tested and observed. Until now, water absorption has tended to be emphasized in resin encapsulation, that is, encapsulation in which the resin is in direct contact with the element. It is self-evident that the moisture permeability of water has a significant effect on moisture resistance.

The present inventors have found that the moisture permeability of the ultraviolet-curable resin composition as the adhesive resin is greatly affected by the shape, properties and amount of the inorganic filler added to the composition. That is, at least one inorganic filler (c) selected from the group consisting of a plate-like inorganic filler and a flaky inorganic filler is an essential component, and is contained in the ultraviolet-curable resin composition in an amount of 20% by weight or more. If you have
It has been found that the moisture permeability is reduced, and in a moisture resistance test of the element, a characteristic variation defect considered to be caused by the intrusion of moisture into the package rarely occurs.

The plate-like inorganic filler and the scaly inorganic filler are:
In most cases, it is an inorganic filler having a cleavage property. Cleavage means that a crystal is formed as described in “Chemical Dictionary of Standard Terms”, edited by The Chemical Society of Japan, p. 569 (Maruzen, 1991). It means that it is easily broken or peeled off in a certain direction, and a smooth surface (cleavage surface) appears. That is, as long as the particles have cleavage, each particle becomes plate-like or scale-like. Examples of such an inorganic filler include talc, mica, mica and the like, but glass flakes may be used as long as they satisfy the shape requirements, and are not particularly limited.

[0009] The addition amount of these inorganic fillers is also an important factor. In the ultraviolet-curable resin composition of the present invention, the content of at least one inorganic filler selected from the group consisting of a plate-like inorganic filler and a flaky inorganic filler is 20% by weight. The inventors have found that the moisture permeability is rapidly reduced.

Further, the particle size is also important. Average particle size is 1
When it is 0 μm or less, it is more advantageous for realizing low moisture permeability. In addition, if the content of at least one inorganic filler selected from the group consisting of a plate-like inorganic filler and a flaky inorganic filler is contained in the resin composition in an amount of 20% by weight or more, if necessary, There is no problem in adding an amorphous or spherical inorganic filler.

The epoxy compound (a) having two or more epoxy groups in one molecule, which is an essential component of the resin composition of the present invention, preferably has an aromatic ring. It is at least one selected from the group consisting of naphthalene-type epoxy resins, and it is more preferable that a bisphenol-type epoxy resin and a naphthalene-type epoxy resin are simultaneously contained. The bisphenol-type epoxy resin is characterized in that the molecule itself has water repellency and moisture permeability due to the presence of an aromatic ring in the molecule, and also has a low viscosity.
In particular, a diglycidyl etherified product of 2,2'-bis (4-hydroxyphenyl) ethane is preferable because of its low viscosity and good solubility of other components such as an initiator. Further, although the naphthalene type epoxy resin has a disadvantage of high viscosity, it can realize extremely good low moisture permeability, and the combination with the bisphenol type epoxy resin is very effective.

The photo-cationic curing initiator (b), which is another essential component of the resin composition of the present invention, includes several types such as diazonium salts, iodonium salts, and sulfonium salts, but has poor moisture permeability. The structure of the counter anion is more important than the structure on the cation side. The counter anion is hexafluoroantimonate,
Preferably, it is tetrakis (pentafluorophenyl) borate. As the photocationic curing initiator (b),
When hexafluoroantimonate or tetrakis (pentafluorophenyl) borate is used, the activity of the acid (proton) generated by the irradiation of ultraviolet rays increases, the crosslink density of the ultraviolet-curable resin composition increases, and the moisture permeability decreases.

In the present invention, the adhesion to each adhesive member during moisture absorption is also important. If a silane coupling agent (d) is further added in addition to the epoxy compound (a), the cationic photo-curing initiator (b), and the inorganic filler (c), the adhesion of the interface is further enhanced, and The water which invades from can be suppressed. As the silane coupling agent, those having an epoxy group are more preferable in terms of reactivity.

The UV-curable resin composition according to the present invention may further include an elastomer for obtaining flexibility, an antifoaming agent, a thixotropic agent, a diluent, and an auxiliary thermosetting curing accelerator. Can be added as needed.

[0015]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited thereto.

(Examples 1 to 5 and Comparative Examples 1 to 5) Table 1
Each component was heated, melted, and mixed with a disperser according to the formulation shown in (Example) and Table 2 (Comparative Example).
After mixing, the mixture was kneaded using three 5-inch rolls to obtain a viscous liquid UV-curable resin composition. Using this resin composition, moisture permeability and hermetic sealing were evaluated by the following methods. The evaluation results are collectively shown in Tables 1 and 2. Comparative Example 5 is a thermosetting adhesive.
Comparative Example 4 is a case according to Japanese Patent Application Laid-Open No. 7-109333.

(Preparation of Cured Product) On a glass plate of 80 × 80 × 1 mm, a pressure-sensitive adhesive tape having a thickness of 0.3 mm was used.
A frame of × 40 mm is formed. The ultraviolet curable resin composition is poured into this frame, another glass plate of 80 × 80 × 1 mm is gently overlapped so that air bubbles do not mix, and the glass plate is placed on the glass plate so that the resin spreads over the entire frame. From 2k
g of weight was placed thereon and allowed to stand for 5 minutes, and then cured by irradiating with an ultra-high pressure mercury lamp at an illuminance of 45 mW / cm ² for 240 seconds to obtain a cured product. Since Comparative Example 5 was a thermosetting resin, it was cured under the thermosetting condition of 50 ° C. for 3 hours.

(Evaluation of moisture permeability) Diameter 25 mm, capacity 20
10 g of calcium chloride was placed in a glass bottle of cc, and a cured resin product prepared by the method described in the preceding section was cut out into a size of 27 mm in diameter. The sample was bonded and fixed to the opening to prepare a sample for evaluating moisture permeability. This moisture permeability evaluation sample was
The sample was placed in a high-temperature and high-humidity tank set at 5 ° C. and a humidity of 85%, and the weight of the sample was measured every 24 hours up to 120 hours. The obtained measured weight values were plotted against the time axis, and the slope calculated by the least squares method was defined as the moisture permeability.

(Evaluation of Hermetic Sealing) Simulated hollow package 1 made of ceramic having the shape and dimensions (unit: mm) shown in FIG.
Then, 10 milligrams of calcium chloride was added thereto, and the ultraviolet-curable resin compositions of Examples and Comparative Examples were applied to a margin 2 using a dispenser, and a quartz glass lid 3 shown in FIG. Then, using a super-high pressure mercury lamp, the cover 3 was fixed by irradiating ultraviolet rays at an illuminance of 45 mW / cm ² for 120 seconds. In addition, about Comparative Example 5, 5
The composition was cured under the thermosetting condition of 0 ° C. for 3 hours, and the lid was fixed.

Next, for the package sample,
After processing at 85 ° C and 85% humidity for 2000 hours,
The inside was observed, and it was confirmed whether or not the calcium chloride therein had absorbed and deliquesced. If there is no deliquescence due to absorption of calcium chloride, it means that the moisture resistance is good. Also,
It was confirmed whether or not the bonding interface between the package and the quartz glass had peeled off. No peeling means good interfacial adhesion.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

When the ultraviolet-curable resin composition of the present invention is used for hermetic sealing of a photoelectric element, a light-emitting element, etc., the element is protected from a change in temperature or humidity of the external environment, and the reliability is extremely high. It can be held at a level, and the present invention is extremely useful in the electronics field.

[Brief description of the drawings]

FIG. 1 is a view showing a shape of a simulated hollow package made of ceramic used for evaluation of hermetic sealing characteristics of a resin composition.

FIG. 2 is a view showing the shape of a glass lid for a simulated hollow package made of ceramic used for evaluating the hermetic sealing properties of a resin composition.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Simulated hollow package made of ceramics 2 Paste 3 Glass lid for simulated hollow package

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 23/08 H01L 23/08 A F term (Reference) 4J002 CD041 CD051 DJ046 DJ056 EN137 EQ017 EV297 EW177 FA016 FD016 FD147 GP00 4J036 AA01 AC01 AC05 AD08 FA01 FA05 FA06 GA01 GA03 GA06 GA28 HA02

Claims (10)

[Claims] 1. An epoxy compound having two or more epoxy groups per molecule (a), a cationic photocuring initiator (b), and a plate-like inorganic filler and a flaky inorganic filler. An ultraviolet curable resin composition comprising at least one inorganic filler (c) as an essential component, and the resin composition containing 20% by weight or more of the inorganic filler (c). 2. An epoxy compound having two or more epoxy groups in one molecule (a), a cationic cationic curing initiator (b), a plate-like inorganic filler and a flake-like inorganic filler. At least one inorganic filler (c),
And a silane coupling agent (d) as an essential component,
An ultraviolet curable resin composition, wherein the inorganic filler (c) is contained in the resin composition in an amount of 20% by weight or more. 3. The ultraviolet-curable resin composition according to claim 1, wherein the epoxy compound (a) has an aromatic ring. 4. An epoxy compound having an aromatic ring (a)
Is at least one member selected from the group consisting of bisphenol-type epoxy resin and naphthalene-type epoxy resin. 5. An epoxy compound having an aromatic ring (a)
Contains both a bisphenol-type epoxy resin and a naphthalene-type epoxy resin as essential components. 4. The ultraviolet-curable resin composition according to claim 3, wherein 6. The bisphenol type epoxy resin is 2,2 ′
The ultraviolet-curable resin according to claim 5, wherein the resin is a diglycidyl ether of bis- (4-hydroxyphenyl) ethane, and the naphthalene-type epoxy resin is a diglycidyl ether of 1,6-dihydroxynaphthalene. Composition. 7. The photocationic curing initiator (b) comprises at least one counter anion selected from the group consisting of hexafluoroantimonate and tetrakis (pentafluorophenyl) borate. The ultraviolet-curable resin composition according to claim 1 or 2. 8. The method according to claim 1, wherein the inorganic filler (c) is talc, mica,
The UV-curable resin composition according to claim 1, wherein the resin composition is at least one selected from the group consisting of mica and mica. 9. The inorganic filler (c) has an average particle size of 10 μm.
3. The ultraviolet-curable resin composition according to claim 1, wherein m is equal to or less than m. 4. 10. An epoxy compound (a) comprising a diglycidyl etherified product of 2,2′-bis (4-hydroxyphenyl) ethane and a diglycidyl etherified product of 1,6-dihydroxynaphthalene, and 2. The ultraviolet-curable resin composition according to claim 1, wherein a photo-cationic curing initiator (b) having a salt as a counter anion and talc having an average particle diameter of 10 μm or less are blended as an inorganic filler (c). object.