JPH05287082A - Method for producing ultrafine particle dispersed resin composition - Google Patents

Abstract

(57) [Summary] [Structure] An ultrafine particle-dispersed resin composition is prepared by previously dispersing ultrafine particles in an organic solvent, mixing the ultrafine particle dispersion solution and a resin component, and dispersing the ultrafine particles in the resin component. To make. [Effect] The internal stress is reduced and the light transmission is excellent. Therefore, when it is used as a resin composition for encapsulating an optical semiconductor element, the problem of deterioration in brightness does not occur.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an ultrafine particle-dispersed resin composition excellent in both light transmission and low stress.

[0002]

2. Description of the Related Art Conventionally, in the field of optoelectronics, transparent resins have been used as, for example, optical adhesives, optical fiber materials, optical semiconductor sealing materials, and the like.
However, when the transparent resin is used, internal stress occurs,
As a result, there arises a problem that the function of the optical device is deteriorated. For example, in the case of a light emitting diode (LED), when a transparent resin is used as a sealing resin, the brightness is reduced due to stress generation. Therefore, it is desired to reduce the internal stress while maintaining the high transparency of the transparent resin. Then, in order to achieve the above demands, the present inventors have already filled the transparent resin with silica-based particles sufficiently smaller than the wavelength of light to reduce the linear expansion coefficient of the resin, We have found that a sealing resin that is transparent and has a low internal stress can be obtained and applied (Japanese Patent Application No. 3-1
33418).

[0003]

However, since the ultrafine particles, which are sufficiently smaller than the wavelength of light, have a very large surface area, they are in an unstable state when simply mixed with a transparent resin and kneaded. It will aggregate. As a result, the particles are formed into large particles, and the resin as a whole becomes clouded to reduce the transparency, so that the method as described above has high transparency and low internal stress. Is still insufficient.

The present invention has been made in view of such circumstances, and an object thereof is to provide a method for producing an ultrafine particle-dispersed resin composition excellent in both light transmittance and low stress.

[0005]

In order to achieve the above object, the method for producing an ultrafine particle-dispersed resin composition of the present invention is to disperse ultrafine particles in an organic solvent in advance, and then to prepare the ultrafine particle dispersed solution and the resin component. A configuration is adopted in which the ultrafine particles are mixed and dispersed in the resin component.

[0006]

In other words, the present inventors have a small internal stress,
Moreover, a series of studies were conducted in order to obtain a sealing resin having excellent light transmittance. As a result, the ultrafine particles are not simply kneaded into the resin component, but the ultrafine particles are dispersed in an organic solvent in advance, and then the ultrafine particle dispersion solution and the resin component are mixed. It was found that they were uniformly dispersed without secondary aggregation. The inventors have found that the intended purpose can be achieved by using the ultrafine particle-dispersed resin composition obtained by this method as a resin composition for encapsulating an optical semiconductor element, and have reached the present invention.

Next, the present invention will be described in detail.

In the method of producing a resin composition containing ultrafine particles dispersed therein, ultrafine particles, an organic solvent in which the ultrafine particles are dispersed, and a resin component are used.

As the above-mentioned ultrafine particles, silica-based fine particles are used when encapsulating an optical semiconductor element, and in order to express transparency, it is preferable to use those having a particle diameter of 0.1 μm or less. It is particularly preferably 0.02 μm or less. Such fine silica-based fine particles are synthesized, for example, by reacting an alkoxysilane in the presence of water. Alternatively, it is synthesized by polymerizing silicic acid obtained by removing sodium ions from sodium silicate in water. The silica-based fine particles thus synthesized are dispersed in water, and in order to disperse them in the organic solvent, the water may be gradually replaced with the organic solvent. For example, when substituting with a water-insoluble organic solvent such as xylene or methyl isobutyl ketone, it may be once replaced with a water-soluble organic solvent such as alcohols.

As the organic solvent for dispersing the ultrafine particles, those capable of dissolving the resin component are used, and for example, methanol, ethanol, propanol, butanol, xylene, toluene, hexane, ethylene glycol, methyl ether, methyl ethyl ether, Ethyl ether,
Examples include propyl ether, tetrahydrofuran, dimethylacetamide, dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, dioxane, methyl isobutyl ketone, and the like. These may be used alone or in combination.

Water may be used if the resin components to be mixed later are water-soluble.

A surfactant can be used to improve the dispersibility of the ultrafine particles. The surfactant is appropriately selected depending on the type of the organic solvent. And considering the moisture resistance reliability of the optical semiconductor device,
It is preferable to use a nonionic one.

The resin component may be either a thermoplastic resin or a thermosetting resin as long as it is soluble in the organic solvent.

Examples of the thermoplastic resin include acrylic resins such as polymethyl methacrylate, polyethyl acrylate, polybutyl acrylate, polyethyl acrylate, polymethyl acrylate and polyacrylamide, polystyrene, polycarbonate, polysulfone and polyvinyl alcohol. .. And the above resin is
It may be a copolymer.

Examples of the thermosetting resin include epoxy resin and polyimide.

Among the above resins, a transparent epoxy resin is preferably used as the optical semiconductor encapsulating resin, and examples of the transparent epoxy resin include bisphenol type epoxy resin and alicyclic epoxy resin. Be done. Moreover, you may use together another epoxy resin, for example, triglycidyl isocyanurate etc. depending on the case. When the other epoxy resin is used in combination, it is usually preferable to set the blending ratio to 50% by weight (hereinafter abbreviated as “%”) or less of the entire epoxy resin. Such an epoxy resin generally has an epoxy equivalent of 1
Those having a softening point of 120 to 1000 ° C. or less are used. In addition, the transparency of the transparent epoxy resin includes a case of being colored and transparent, and having a thickness of 1 mm and a light transmittance of 80 to 100% at a wavelength of 600 nm (measured by a spectrophotometer).

Further, the above-mentioned resin component includes conventionally known additives such as a curing agent, a curing catalyst, a dye, a modifier, a discoloration preventing agent, an antiaging agent, a releasing agent, a reactive or non-reactive diluent and the like. Can be added.

Examples of the above-mentioned curing agent, especially the curing agent for transparent epoxy resin, include acid anhydride type curing agents. The acid anhydride-based curing agent has a molecular weight of about 140 to
It is preferable to use 200, and specific examples thereof include colorless or pale yellow acid anhydrides such as hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride. The compounding amount of the acid anhydride-based curing agent is 5 with respect to 100 parts by weight of the transparent epoxy resin (hereinafter abbreviated as “part”).
It is preferably set in the range of 0 to 200 parts.

Examples of the curing catalyst include tertiary amines, imidazole compounds and organometallic complex salts.

The ultrafine particle-dispersed resin composition according to the present invention is produced, for example, as follows using the above components. That is, first, ultrafine particles are dispersed in an organic solvent in advance. Next, the organic solvent solution in which the ultrafine particles are dispersed is mixed with a resin component to disperse the ultrafine particles in the resin component. At this time, the resin component may be dissolved by heating if necessary. In this way, the ultrafine particle dispersed resin composition is manufactured.

Then, the resin composition in which the ultrafine particles are dispersed is desolvated to prepare a resin composition.

The desolvation is carried out by reducing the pressure at room temperature or heating.

When the above ultrafine particles are dispersed in an organic solvent, when the dispersibility in the organic solvent is not good, or when the ultrafine particles are synthesized in water, they are dispersed in water. Therefore, water may be gradually replaced with an organic solvent.

Further, a curing agent added to the above resin component,
Conventionally known additives such as a curing catalyst, a dye, a modifier, a discoloration preventing agent, an antiaging agent, a releasing agent, a reactive or non-reactive diluent, etc. may be added after the completion of the solvent removal.

[0025]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, the ultrafine particles are dispersed in the organic solvent in advance, and then this ultrafine particle dispersion solution is mixed with the resin component to disperse the ultrafine particles in the resin component. A dispersed resin composition is manufactured. Therefore, ultrafine particles are uniformly dispersed in the obtained resin composition, and when this is used as, for example, a resin material for sealing an optical semiconductor element, not only low stress but also light transmittance is obtained. Excellent results are obtained.

Next, examples will be described together with comparative examples.

[0027]

Example 1 First, a silica-based fine particle dispersion solution was prepared in which 60 parts of silica-based fine particles having an average particle diameter of 18 nm were dispersed in an organic solvent consisting of 140 parts of methyl isobutyl ketone and 1 part of a nonionic surfactant. Next, 60.6 parts of an epoxy resin composition having the composition shown below was added to the above silica-based fine particle dispersion solution, and the resin component was dissolved at 100 ° C.

[Composition of Epoxy Resin Composition] Bisphenol A type epoxy resin (epoxy equivalent 185) 30.0 parts Methylhexahydrophthalic anhydride 30.0 parts Anti-aging agent 0.6 parts

Then, this was depressurized to remove the solvent, and 2-ethyl-4-methylimidazole.
Two parts were added and mixed to obtain a silica-based fine particle-dispersed transparent resin composition. The light transmittance of a cured product obtained by thermosetting the silica-based fine particle-dispersed transparent resin composition thus obtained at 120 ° C. was as high as 85% at a thickness of 4 mm.

[0030]

Example 2 First, a silica-based fine particle dispersion solution was prepared in which 180 parts of silica-based fine particles having an average particle diameter of 14 nm were dispersed in an organic solvent consisting of 420 parts of dimethylacetamide and 3 parts of a nonionic surfactant. Then, 75 parts of an epoxy resin composition having the composition shown below was added to the above silica-based fine particle dispersion solution, and the resin component was dissolved at 110 ° C.

[Composition of Epoxy Resin Composition] Bisphenol A type epoxy resin (epoxy equivalent 640) 40.0 parts Triglycidyl isocyanurate 10.0 parts Tetrahydrophthalic anhydride 22.0 parts Anti-aging agent 3.0 parts

Then, this was depressurized to remove the solvent, and then 2-ethyl-4-methylimidazole.
4 parts were added and mixed to obtain a silica-based fine particle-dispersed transparent resin composition. The light transmittance of a cured product obtained by thermosetting the silica-based fine particle-dispersed transparent resin composition thus obtained at 150 ° C. was as high as 85% at a thickness of 4 mm.

[0033]

Comparative Example 60 parts of silica-based fine particles having an average particle size of 50 nm, and an epoxy resin composition 60.
6 parts were mixed.

[Composition of Epoxy Resin Composition] Bisphenol A type epoxy resin (epoxy equivalent 185) 30.0 parts Methylhexahydrophthalic anhydride 30.0 parts Anti-aging agent 0.6 parts 2-Ethyl-4-methylimidazole 0.2 part

With this product, the silica-based fine particles aggregated and the resin composition became cloudy, so that a product having high transparency could not be obtained.

Claims (3)

[Claims] 1. An ultrafine particle-dispersed resin composition, which comprises dispersing ultrafine particles in an organic solvent in advance, and then mixing the ultrafine particle dispersion solution with a resin component to disperse the ultrafine particles in the resin component. Manufacturing method. 2. The resin component is a transparent epoxy resin,
The method for producing an ultrafine particle-dispersed resin composition according to claim 1, wherein the transparent epoxy resin and the dispersion solution of ultrafine particles are uniformly mixed and then desolvated to produce a transparent epoxy resin composition. 3. The method for producing an ultrafine particle-dispersed resin composition according to claim 1, wherein the ultrafine particles have a particle size of 0.1 μm or less.