JPWO2014073621A1 - Epoxy resin composition, cured product thereof and light-emitting diode - Google Patents

Abstract

The epoxy resin composition of the present invention contains an acid anhydride (A) and an epoxy resin (B), and (a) the acid anhydride (A) is cyclohexane-1,2,4-tricarboxylic acid-1,2- 30 to 90% by mass of anhydride, (b) epoxy resin (B) contains 30 to 90% by mass of alicyclic epoxy resin compound, glycidyl ester type epoxy resin compound, (c) The mixing | blending equivalent ratio of the acid anhydride represented by Formula (1) and an epoxy resin is the range of 0.4-0.7. Compounding equivalent ratio of acid anhydride and epoxy resin = (X + Y) / Z (1) X: number of functional groups of acid anhydride group contained in acid anhydride (A) Y: contained in acid anhydride (A) Number of functional groups of the carboxyl group Z: number of functional groups of the epoxy group contained in the epoxy resin (B)

Description

  The present invention relates to an epoxy resin composition, a cured product thereof, and a light emitting diode.

  In recent years, high-intensity blue and white light-emitting diodes (hereinafter abbreviated as “LEDs”) have been developed, and their uses have expanded to bulletin boards, full-color displays, mobile phone backlights, and the like. Conventionally, an acid anhydride-cured epoxy resin is excellent in colorless transparency, and thus has been used as a sealing material for photoelectric conversion elements such as LEDs.

  As a curing agent for the epoxy resin used for the sealing material of such a photoelectric conversion element, alicyclic acid anhydrides such as methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride are generally used. Has been used.

  When used for blue LED or white LED applications, the epoxy resin cured product is exposed to high intensity of LED light for a long time at a high temperature. Colorless transparency of the product is required.

  A cured product obtained by using the curing agent as described above is not preferable for a sealing material for a photoelectric conversion element such as a high-brightness LED, because colorless transparency is easily impaired.

  Therefore, cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (hydrogenated trimellitic anhydride as a curing agent for obtaining a colorless and transparent epoxy resin cured product having improved light resistance and heat resistance. (Refer to Patent Documents 1 to 4, for example).

  Moreover, the epoxy resin composition using H-TMAn is also known (for example, refer patent document 5).

JP 2005-36218 A JP 2006-182961 A JP 2007-39521 A JP 2007-39522 A International Publication No. 2009/041389

  However, the epoxy resin compositions described in Patent Documents 1 to 4 have a high viscosity and a high curing rate. For this reason, the epoxy resin compositions described in Patent Documents 1 to 4 have a high viscosity increase ratio when left at room temperature within daytime working hours, and workability may be deteriorated. In addition, the epoxy resin compositions described in Patent Documents 1 to 4 do not have sufficient colorless transparency (heat resistant colorability) under heating conditions in high-luminance LED applications.

  The epoxy resin composition described in Patent Document 5 improves such problems, and has low viscosity and improved workability. In addition, the epoxy resin composition described in Patent Document 5 has colorless transparency (light coloring resistance) and heat resistance coloring property under UV irradiation as compared with a composition using a general alicyclic acid anhydride. It is greatly improved and sufficient for the level (150 ° C. 120 hours or 180 ° C. 48 hours) required for a resin (hereinafter also referred to as “sealing resin”) used as a sealing material for general photoelectric conversion elements. Shows heat resistance colorability. However, the temperature applied to the sealing resin tends to increase due to the effects of higher power and higher current of recent LEDs. As a result, in recent years, the sealing resin has been required to have a higher level of heat resistance coloring (typically 150 ° C. for 1000 hours). Under such circumstances, the epoxy composition described in Patent Document 5 may not have sufficient heat resistant colorability, and there is room for improvement.

The object of the present invention is to provide an epoxy resin composition having the following characteristics (1) to (3) and suitable as a sealing material for photoelectric conversion elements such as blue LEDs and white LEDs, and a cured product thereof. There is.
(1) The viscosity after preparation is low, the viscosity increase ratio at room temperature is low, and the workability is excellent.
(2) Curability is good without adding a curing accelerator.
(3) The obtained cured product is colorless and transparent, excellent in crack resistance, and has little coloration under prolonged light irradiation and heating at 150 ° C. for 1000 hours.

  As a result of intensive studies to solve the above problems, the present inventors have found that an acid anhydride containing a specific amount of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (H-TMAn) and a specific amount And an epoxy resin containing a alicyclic epoxy resin compound and a glycidyl ester type epoxy resin compound, and the resin composition having a specific concentration range of acid anhydride and epoxy resin can achieve the above-mentioned object. The present invention has been reached.

That is, this invention provides the following epoxy resin compositions, its hardened | cured material, and a light emitting diode.
1. Containing an acid anhydride (A) and an epoxy resin (B),
(A) The acid anhydride (A) contains 30 to 90% by mass of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride,
(B) The epoxy resin (B) contains 30 to 90% by mass of the alicyclic epoxy resin compound, contains the glycidyl ester type epoxy resin compound,
(C) The epoxy resin composition whose compounding equivalent ratio of the acid anhydride and epoxy resin represented by following formula (1) is the range of 0.4-0.7.
Compounding equivalent ratio of acid anhydride and epoxy resin = (X + Y) / Z (1)
X: Number of functional groups of acid anhydride group contained in acid anhydride (A) Y: Number of functional groups of carboxyl group contained in acid anhydride (A) Z: Number of functional groups of epoxy group contained in epoxy resin (B) Number of functional groups The epoxy resin composition according to 1 above, wherein the content of the glycidyl ester type epoxy resin compound in the epoxy resin (B) is 10 to 60% by mass.
3. The glycidyl ester type epoxy resin compound is at least one selected from the group consisting of adipic acid diglycidyl ester, long-chain dibasic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester and hexahydrophthalic acid diglycidyl ester, 1 or 2 epoxy resin composition.
4). 4. The epoxy resin composition according to any one of 1 to 3, wherein the alicyclic epoxy resin compound is 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate.
5. Furthermore, the epoxy resin composition in any one of said 1-4 which contains 0.1-5 mass% of hindered phenolic antioxidants.
6). Furthermore, the epoxy resin composition according to any one of 1 to 5 above, containing 0.01 to 5% by mass of a phosphorus curing accelerator.
7). Furthermore, the epoxy resin according to any one of the above 1 to 6, further comprising a fluorescent material capable of emitting fluorescence by absorbing at least part of light emitted from a light emitting element having a main emission peak wavelength of 550 nm or less. Composition.
8). A cured epoxy resin obtained by curing the epoxy resin composition according to any one of 1 to 7 above.
9. A light emitting diode in which a light emitting element is sealed with the cured epoxy resin according to 8 above.

The epoxy resin composition of the present invention has the following effects (1) to (3).
(1) The workability is good because the viscosity after blending is low and the viscosity increase factor at room temperature within the daytime working time is low.
(2) Curability is good without adding a curing accelerator.
(3) The obtained cured product is colorless and transparent, excellent in crack resistance, and has very little coloring even under long-time light irradiation and heating at 150 ° C. for 1000 hours.

  In addition, the epoxy resin composition of the present invention can provide a cured product that is less colored by heating and excellent in heat-resistant colorability, although the speed of thickening increases by using a specific curing accelerator.

  Furthermore, since the epoxy resin composition of the present invention has the effects as described above, for example, sealing materials for photoelectric conversion elements such as blue LEDs and white LEDs, coating materials, paints, adhesives, and various moldings. Products, insulating members, decorative materials, etc., which are suitably used for applications that require more heat-resistant coloring.

  Hereinafter, embodiments of the present invention (hereinafter also referred to as “present embodiments”) will be described in detail. In addition, the following embodiment is an illustration for demonstrating this invention, and this invention is not limited only to the embodiment.

≪Epoxy resin composition≫
The epoxy resin composition of this embodiment contains the acid anhydride (A) and epoxy resin (B) of a specific composition.

<Acid anhydride (A)>
The acid anhydride (A) used for the epoxy resin composition of this embodiment contains 30 to 90% by mass of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride. When the acid anhydride (A) contains 30 to 90% by mass of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, the cured product of the resulting epoxy resin composition is excellent in crack resistance.

  In the acid anhydride (A), the content of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (hereinafter also referred to as “H-TMAn”) is 30 to 90% by mass, 40 It is preferable that it is -90 mass%, and it is more preferable that it is 50-90 mass%.

  In the acid anhydride (A), when the content of H-TMAn is 30% by mass or more, the performance (crack resistance) imparted to the cured product that H-TMAn originally has is further expressed. When the TMAn content is 90% by mass or less, the resulting epoxy resin composition has a reduced viscosity, and the workability is further improved.

  In the acid anhydride (A), the content of H-TMAn can be appropriately selected in the range of 30 to 90% by mass according to the use and required performance of the epoxy resin composition. For example, if importance is attached to the crack resistance of the cured product of the epoxy resin composition, the content of H-TMAn in the acid anhydride (A) is preferably 40% by mass or more, and more preferably 50% by mass or more. More preferably, it is more preferably 60% by mass or more. Moreover, it is preferable that it is 85 mass% or less from a viewpoint of the viscosity of an epoxy resin composition, and, as for the upper limit of content of H-TMAn in an acid anhydride (A), it is more preferable that it is 80 mass% or less.

  In this embodiment, the content of H-TMAn in the acid anhydride (A) in the epoxy resin composition can be measured by component analysis by nuclear magnetic resonance (NMR) or gas chromatography (GC). .

  The acid anhydride (A) used in the present embodiment may contain an acid anhydride other than H-TMAn. Acid anhydrides other than H-TMAn are not particularly limited. For example, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic acid anhydride, trialkyltetrahydro Phthalic anhydride, methylcyclohexene tetracarboxylic dianhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic dianhydride, ethylene glycol bisanhydro trimellitate, glycerin (anhydro trimelli Tate) monoacetate, dodecenyl succinic anhydride, aliphatic dibasic acid polyanhydride, chlorendic anhydride and the like.

  In particular, considering the low viscosity and improved workability of the epoxy resin composition and the crack resistance and light resistance of the cured product, acid anhydrides other than H-TMAn include hexahydrophthalic anhydride and methylhexahydroanhydride. It is preferable to use an acid anhydride having a low viscosity such as phthalic acid and containing no double bond. These acid anhydrides can be used for dilution of H-TMAn, for example, alone or in combination with a plurality of acid anhydrides.

<Epoxy resin (B)>
The epoxy resin (B) used by the epoxy resin composition of this embodiment contains 30-90 mass% of alicyclic epoxy resin compounds, and contains a glycidyl ester type epoxy resin compound. When the epoxy resin (B) contains 30 to 90% by mass of the alicyclic epoxy resin compound, the cured product of the epoxy resin composition is excellent in heat resistant colorability. On the other hand, when the epoxy resin (B) contains a glycidyl ester type epoxy resin compound, the cured product of the epoxy resin composition has increased flexibility and can suppress the occurrence of cracks due to heat shock.

  In the epoxy resin (B), the content of the alicyclic epoxy resin compound is preferably 30 to 90% by mass, and the content of the glycidyl ester type epoxy resin compound is preferably 10 to 60% by mass.

  Therefore, the epoxy resin (B) may be composed of only an alicyclic epoxy resin compound and a glycidyl ester type epoxy resin compound, or may further contain another epoxy resin compound. The total content of the alicyclic epoxy resin compound and the glycidyl ester type epoxy resin compound in the epoxy resin (B) is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more. Moreover, the upper limit of the total content of the alicyclic epoxy resin compound and the glycidyl ester type epoxy resin compound in the epoxy resin (B) is not particularly limited, but is, for example, 100% by mass. When the total content of the alicyclic epoxy resin compound and the glycidyl ester type epoxy resin compound in the epoxy resin (B) is within the above range, the cured product of the epoxy resin composition is further layered by heat resistance coloring and crack resistance. Excellent.

  An alicyclic epoxy resin compound is an epoxy resin having an alicyclic ring in its molecule and a part of the C—C bond forming the ring being shared with the epoxy ring. The alicyclic epoxy resin compound is not particularly limited, and examples thereof include 3,4-epoxycyclohexenylmethyl-3 ', 4'-epoxycyclohexenecarboxylate, vinylcyclohexene diepoxide, and the like. Of these, 3,4-epoxycyclohexenylmethyl-3 ', 4'-epoxycyclohexenecarboxylate is preferably used from the viewpoint of low viscosity and economy.

  The glycidyl ester type epoxy resin compound is an epoxy resin having a glycidyl ester moiety in the molecule. The glycidyl ester type epoxy resin compound is not particularly limited, and examples thereof include aliphatic compounds such as adipic acid diglycidyl ester and long-chain dibasic acid diglycidyl ester, and aromatic compounds such as phthalic acid diglycidyl ester and terephthalic acid diglycidyl ester. And alicyclic systems such as tetrahydrophthalic acid diglycidyl ester and hexahydrophthalic acid diglycidyl ester. Among these, adipic acid diglycidyl ester, long-chain dibasic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester and hexahydrophthalic acid diglycidyl from the viewpoint of the viscosity of the epoxy resin composition and the color resistance of the cured product. It is preferably at least one selected from the group consisting of esters, and hexahydrophthalic acid diglycidyl ester is more preferable.

  In the epoxy resin (B), the content of the alicyclic epoxy resin compound is 30 to 90% by mass, preferably 40 to 85% by mass, and more preferably 50 to 80% by mass. In the epoxy resin (B), the more the content of the alicyclic epoxy resin compound, the higher the color resistance of the cured product of the epoxy resin composition, and the content of the alicyclic epoxy resin compound is the lower limit value. When it is above, the cured product of the epoxy resin composition is further excellent in heat-resistant colorability. Further, in the epoxy resin (B), when the content of the alicyclic epoxy resin compound is not more than the above upper limit value, the cured product of the epoxy resin composition becomes flexible and can suppress the occurrence of cracks against heat shock, The heat resistance coloring property is further improved.

  On the other hand, the glycidyl ester type epoxy resin compound in the epoxy resin (B) can increase the flexibility of the cured product of the epoxy resin composition and suppress the occurrence of cracks due to heat shock. In the epoxy resin (B), the content of the glycidyl ester type epoxy resin compound is preferably 10 to 60% by mass, more preferably 15 to 50% by mass, and further preferably 20 to 40% by mass. preferable. In the epoxy resin (B), when the content of the glycidyl ester type epoxy resin compound is not less than the lower limit, the cured product of the epoxy resin composition is further excellent in crack resistance. Moreover, in epoxy resin (B), when content of a glycidyl ester type epoxy resin compound is below the said upper limit, the hardened | cured material of an epoxy resin composition is further excellent in heat-resistant coloring.

  In this embodiment, the content of the alicyclic epoxy resin compound or the glycidyl ester type epoxy resin compound in the epoxy resin (B) in the epoxy resin composition or its cured product is determined by nuclear magnetic resonance (NMR) or gas chromatography. It can be measured by component analysis by chromatography (GC).

  Moreover, the epoxy resin (B) may contain other epoxy resin compounds other than the said alicyclic epoxy resin compound and a glycidyl ester type epoxy resin compound. Other epoxy resin compounds are not particularly limited. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, biphenyl type epoxy resin, stilbene type epoxy resin, hydroquinone Type epoxy resin, naphthalene skeleton type epoxy resin, tetraphenylolethane type epoxy resin, trishydroxyphenylmethane type epoxy resin, dicyclopentadiene phenol type epoxy resin, diglycidyl ether of bisphenol A ethylene oxide adduct, bisphenol A propylene oxide addition Glycidyl ether having one epoxy group such as diglycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, etc. Tel and the like. Moreover, the nuclear hydrogenation epoxy resin which is a nuclear hydrogenation thing of these epoxy resins is mentioned.

  In the epoxy resin (B), the content of other epoxy resin compounds is preferably 30% by mass or less, more preferably 20% by mass or less, and further preferably 10% by mass or less. In the epoxy resin (B), the lower limit of the content of the other epoxy resin compound is not particularly limited, and is, for example, 0% by mass. Other epoxy resin compounds can be used alone or in admixture of two or more within the above content range. In particular, the nuclear hydrogenated epoxy resin is more preferably used because it improves the colorless transparency of the cured product of the epoxy resin composition.

<Blending amount of acid anhydride (A) and epoxy resin (B)>
In the epoxy resin composition of the present embodiment, the blending amount of the acid anhydride (A) and the epoxy resin (B) is such that the blending equivalent ratio of the acid anhydride and the epoxy resin represented by the following formula (1) is 0. The amount is in the range of 4 to 0.7.

Compounding equivalent ratio of acid anhydride and epoxy resin = (X + Y) / Z (1)
X: Number of functional groups of acid anhydride group contained in acid anhydride (A) Y: Number of functional groups of carboxyl group contained in acid anhydride (A) Z: Number of functional groups of epoxy group contained in epoxy resin (B) Number of functional groups

  In the above formula (1), the equivalent of the acid anhydride (A) is the total amount of the functional group number X of the acid anhydride group and the functional group number Y of the carboxyl group contained in the acid anhydride (A). This is because it is considered that one acid anhydride group reacts with one epoxy group and one carboxyl group reacts with one epoxy group.

  For example, when the acid anhydride (A) is cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (H-TMAn), the number of functional groups of the acid anhydride group in one molecule is 1, Since the number of functional groups of the carboxyl group is 1, the equivalent of the acid anhydride is 2. When the epoxy resin (B) is 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate, the number of functional groups of the epoxy group is 2 in one molecule, so the equivalent of the epoxy resin is 2. The same applies to glycidyl ester type epoxy resin compounds.

  In the epoxy resin composition of the present embodiment, the functional group number X of the acid anhydride group contained in the acid anhydride (A) is (number of functional groups of the acid anhydride group of each acid anhydride compound) × (the acid anhydride group). The number of functional groups Y of the carboxyl group contained in the acid anhydride (A) is (the number of functional groups of the carboxyl group of each acid anhydride compound) × (the acid anhydride compound). Of the molar fraction). In the epoxy resin composition of the present embodiment, the number of functional groups Z of the epoxy group contained in the epoxy resin (B) is (the number of functional groups of the epoxy group of each epoxy resin compound) × (mol content of the epoxy resin compound). Rate) total amount.

  In the epoxy resin composition of the present embodiment, the compounding equivalent ratio of the acid anhydride represented by the above formula (1) and the epoxy resin is in the range of 0.4 to 0.7, and 0.4 to 0.6. Is preferably in the range of 0.4 to 0.5.

  In the epoxy resin composition of the present embodiment, when the mixing equivalent ratio of the acid anhydride represented by the above formula (1) and the epoxy resin is equal to or higher than the lower limit, the heat-resistant coloring property of the cured product is improved. When the blending equivalent ratio is less than or equal to the above upper limit value, the remaining unreacted acid anhydride is suppressed, and the heat resistant colorability of the cured product is improved.

  In this embodiment, the compounding equivalent ratio of the acid anhydride represented by the above formula (1) and the epoxy resin in the epoxy resin composition or the cured product thereof is equivalent to the epoxy resin equivalent (epoxy equivalent) and the curing agent. Respectively (an acid anhydride equivalent) can be measured and calculated from the measured value. Further, the epoxy equivalent can be determined by potentiometric measurement using a 0.1 mol / L perchloric acid acetic acid standard solution according to JIS K7236. Furthermore, the acid anhydride equivalent can be calculated based on the analysis result obtained by performing component analysis by nuclear magnetic resonance (NMR) or gas chromatography (GC).

  In the epoxy resin composition of the present embodiment, the total content of the acid anhydride (A) and the epoxy resin (B) is preferably 70 to 100% by mass, and more preferably 80 to 100% by mass. Preferably, it is 90-100 mass%.

  In the epoxy resin composition of the present embodiment, the epoxy resin (B) has a blending amount of the acid anhydride (A) and the epoxy resin (B) within the range of the blending equivalent ratio of the acid anhydride and the epoxy resin. Resin composition immediately after preparing acid anhydride (A) and epoxy resin (B) by adjusting the blending amount of alicyclic epoxy resin compound, glycidyl ester type epoxy resin compound and other epoxy resin compound in The viscosity at 30 ° C. of the product can be reduced to 5 Pa · s or less, and the viscosity increase ratio of the epoxy resin composition after standing for 7 hours at room temperature after preparation [(viscosity of the epoxy resin composition after 7 hours) ) / (Viscosity of epoxy resin composition immediately after preparation)] can be reduced to 3 times or less.

  When the epoxy resin composition of this embodiment is used as a sealing material for photoelectric conversion elements such as LEDs, the viscosity of the epoxy resin composition exceeds 5 Pa · s, or the above-mentioned viscosity increase ratio exceeds 3 times. In some cases, the use of a high-viscosity epoxy resin composition and the workability of the epoxy resin composition are further deteriorated due to a further increase in viscosity of the epoxy resin composition during daytime working hours. The viscosity increase ratio is more preferably 2 times or less in view of workability.

The epoxy resin composition of this embodiment is
An acid anhydride (A) and an epoxy resin (B) are contained,
(A) 30 to 90% by mass of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride is contained in the acid anhydride (A),
(B) The epoxy resin (B) contains 30 to 90% by mass of an alicyclic epoxy resin compound, and contains a glycidyl ester type epoxy resin compound,
(C) By setting the compounding equivalent ratio of the acid anhydride represented by the following formula (1) and the epoxy resin in the range of 0.4 to 0.7, the following effects (1) to (3) are exhibited. .

  Moreover, the epoxy resin composition of this embodiment has a content of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (H-TMAn) in the acid anhydride (A) of 30 to 90 mass. In the epoxy resin (B), the content of the alicyclic epoxy resin compound is 30 to 90% by mass, and the content of the glycidyl ester type epoxy resin compound is 10 to 60% by mass. The effects (1) to (3) are exhibited.

(1) The resulting epoxy resin composition has a low viscosity after preparation, and is excellent in workability since it has a low viscosity increase rate at room temperature within daytime working hours.
(2) The cured product of the resulting epoxy resin composition is colorless and transparent, has crack resistance, and has very little coloring even under prolonged light irradiation and heating at 150 ° C. for 1000 hours.
(3) The curability is good without adding a curing accelerator. Moreover, although the viscosity increase rate of an epoxy resin composition rises by using a specific hardening accelerator, there is little coloring by heating and the hardened | cured material which is excellent in heat-resistant coloring property is obtained.

  The epoxy resin composition having the effects (1) to (3) is suitable as a sealing material for photoelectric conversion elements such as blue LEDs and white LEDs.

<Antioxidant>
The epoxy resin composition of the present embodiment preferably contains an antioxidant when high heat resistance colorability is required. Although it does not specifically limit as antioxidant, For example, hindered phenolic antioxidant, sulfur type antioxidant (mercaptopropionic acid derivative etc.), phosphorus antioxidant (HCA etc.), etc. are mentioned. In particular, hindered phenol antioxidants are effective. Specific examples of the hindered phenol-based antioxidant are not particularly limited. For example, n-octadecyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, triethylene glycol bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy]- 1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5.5] undecane, 2,6-bis (1,1-dimethylethyl) -4-methylphenol (BHT). .

  In the epoxy resin composition of the present embodiment, the content of the antioxidant is preferably 0.1 to 5% by mass, more preferably 0.1 to 4% by mass, and 0.1 to 3%. More preferably, it is mass%. By making content of antioxidant more than the said lower limit, the heat-resistant coloring property of the hardened | cured material of an epoxy resin composition improves. Moreover, by making content of antioxidant into the said upper limit or less, the cured | curing material of an epoxy resin composition does not lose transparency by the bleeding of antioxidant.

<Fluorescent substance>
The epoxy resin composition of the present embodiment absorbs at least a part of light emitted from a light emitting element having a main emission peak wavelength of 550 nm or less when used as a material for sealing a light emitting element of a white LED. It is preferable to include a fluorescent material capable of emitting fluorescence. Such a fluorescent material can emit various colors when combined with a light emitting diode (LED). For example, when a yellow phosphor and a blue LED are combined, white light can be emitted.

  In the epoxy resin composition of the present embodiment, the content of the fluorescent material is preferably 0.01 to 30% by mass, more preferably 0.01 to 20% by mass, and 0.1 to 10% by mass. % Is more preferable.

<Curing accelerator>
The epoxy resin composition of this embodiment has a merit in cost because it cures without using a curing accelerator, but by adding a curing accelerator, the heat resistance of the cured product of the epoxy resin composition is further increased. Colorability can be improved. In a sealing material for a photoelectric conversion element such as an LED that requires more heat resistant colorability, a curing accelerator can be appropriately used according to the required level of heat resistant colorability.

  Although it does not specifically limit as a hardening accelerator, For example, tertiary amines, such as benzyldimethylamine, a tris (dimethylaminomethyl) phenol, a dimethyl cyclohexylamine; 1-cyanoethyl-2-ethyl-4-methylimidazole, 2- Imidazoles such as ethyl-4-methylimidazole and 1-benzyl-2-methylimidazole; organophosphorus compounds such as triphenylphosphine and triphenyl phosphite; tetraphenylphosphonium bromide, tetra-n-butylphosphonium bromide and the like Quaternary phosphonium salts; diazabicycloalkenes such as 1,8-diazabicyclo [5.4.0] undecene-7 and organic acid salts thereof; organometallic compounds such as zinc octylate, tin octylate and aluminum acetylacetone complex Class: Tetraeth Boron trifluoride, boron compounds such as triphenyl borate; ammonium bromide, tetrabutyl ammonium bromide, quaternary ammonium salts such as benzyl triphenyl phosphonium bromide, zinc chloride, metal halides such as stannic chloride.

  Furthermore, the curing accelerator is not particularly limited. For example, a high melting point dispersion type latent accelerator such as a high melting point imidazole compound, dicyandiamide, an amine addition accelerator obtained by adding an amine to an epoxy resin, etc .; -Based, phosphine accelerator-coated microcapsule-type latent accelerator; amine salt type latent curing accelerator, Lewis acid salt, Bronsted acid salt, etc. A latent curing accelerator typified by an oxidative curing accelerator can also be used.

  Of these, phosphorus-based curing accelerators are preferred. Specific examples of the phosphorus curing accelerator are not particularly limited. For example, organic phosphorus compounds such as triphenylphosphine and triphenyl phosphite, tetraphenylphosphonium bromide, tetra-n-butylphosphonium bromide, and benzyltriphenyl. Quaternary phosphonium salts such as phosphonium chloride and benzyltriphenylphosphonium bromide can be mentioned. Use of such a phosphorus-based curing accelerator is more preferable because a cured product having excellent heat-resistant colorability can be obtained.

  These curing accelerators can be used alone or in admixture of two or more.

  In the epoxy resin composition of the present embodiment, the content of the curing accelerator is preferably 0.01 to 5% by mass, more preferably 0.05 to 4% by mass, and 0.1 to 3%. It is more preferable that it is mass%, and it is especially preferable that it is 0.1-1 mass%.

  By making content of a hardening accelerator more than the said lower limit, the heat-resistant coloring property of the hardened | cured material of an epoxy resin composition improves. Moreover, by making content of a hardening accelerator below the said upper limit, the cost at the time of obtaining an epoxy resin composition becomes low, the raise of an epoxy resin composition thickening viscosity can be suppressed, and workability | operativity improves.

<Other additives>
In the epoxy resin composition of the present embodiment, if necessary, an aliphatic polyol such as ethylene glycol and propylene glycol, an aliphatic or aromatic carboxylic acid compound, a carbon dioxide gas generation inhibitor such as a phenol compound, a polyalkylene glycol, etc. Flexibility imparting agent, plasticizer, lubricant, silane-based coupling agent, inorganic filler surface treatment agent, flame retardant, colorant, antistatic agent, leveling agent, ion trap agent, slidability improver, Various rubbers, impact modifiers such as organic polymer beads, thixotropic agents, surfactants, surface tension reducing agents, antifoaming agents, anti-settling agents, light diffusing agents, ultraviolet absorbers, mold release agents, conductivity Additives such as a filler and a low-viscosity solvent for viscosity adjustment can be contained within a range that does not impair the properties of the resulting epoxy resin composition and its cured product.

<How to save>
The epoxy resin composition of this embodiment is divided and stored in two or more components, for example, a component containing an acid anhydride (A) and a component containing an epoxy resin (B), and these are prepared before curing. May be. Moreover, you may preserve | save as an epoxy resin composition which mix | blended each component, and you may use for hardening as it is. When storing as an epoxy resin composition containing each component, it is preferably stored at a low temperature (usually −40 to 15 ° C.).

≪Hardened epoxy resin≫
The cured epoxy resin of this embodiment is obtained by curing the above-described epoxy resin composition.

  The curing method of the epoxy resin composition described above is not particularly limited, and for example, a curing method using a conventionally known curing apparatus such as a closed curing furnace or a tunnel furnace capable of continuous curing can be employed. The heating method in the case of the said hardening is not specifically limited, For example, conventionally well-known methods, such as hot air circulation, infrared heating, high frequency heating, are employable. The curing temperature and curing time are preferably in the range of 30 seconds to 10 hours at 80 to 250 ° C. When it is desired to reduce the internal stress of the cured product, it is preferable to perform pre-curing under conditions of 120 to 180 ° C. and 0.1 to 5 hours after pre-curing under conditions of 80 to 120 ° C. and 0.5 to 5 hours. . When aiming at short-time curing, curing is preferably performed under conditions of 150 to 250 ° C. and 30 seconds to 30 minutes.

  The above-mentioned epoxy resin composition preferably has a weight retention at the time of curing (a ratio of a cured product weight to a weight of the epoxy resin composition before curing) of 97% or more. By appropriately selecting the type and amount of the low-viscosity acid anhydride compound (that is, an acid anhydride compound other than H-TMAn) and the blending ratio of the acid anhydride (A) and the epoxy resin (B), An epoxy resin composition having a high weight retention can be obtained.

≪Light emitting diode≫
The light emitting diode of this embodiment is a light emitting diode in which the light emitting element is sealed with the above-described cured epoxy resin.

  The above-mentioned cured epoxy resin is colorless and transparent, has crack resistance, and has little coloration under long-time heating. For example, it is suitable as a sealing material for light-emitting diodes, particularly blue LED and white LED sealing materials. Can be used.

≪Other uses≫
The epoxy resin composition of the present embodiment is not limited to the above-mentioned applications. For example, other light emitting elements such as LEDs and semiconductor lasers, photoconductive elements, photodiodes, solar cells, phototransistors, photothyristors, etc. Insulating and sealing materials for photoelectric conversion elements typified by optical coupling elements such as light receiving elements, photocouplers, photointerrupters, adhesives such as liquid crystals, resins for optical modeling, and surface coating agents such as plastics, glass, and metals It can also be used for applications that require transparency, such as decorative materials.

  Moreover, the epoxy resin composition of this embodiment is applicable also to the insulation sealing and molding of thickness of 2 mm or more by conventionally well-known methods, such as potting, casting, filament winding, lamination | stacking, for example. Specifically, for example, a mold transformer, a mold transformer (current transformer (CT), zero-layer current transformer (ZCT), instrument transformer (PT), stationary instrument transformer (ZPT)), Gas switch parts (insulation spacers, support insulators, operating rods, sealed terminals, bushings, insulation columns, etc.), solid insulation switch parts, overhead distribution line automation equipment parts (rotary insulators, voltage detection elements, general capacitors, etc.), underground Distribution line equipment parts (molded transformers, power transformers, etc.), power capacitors, resin insulators, heavy electrical insulation insulating seals such as linear motor car coils, impregnating varnishes for various rotating equipment coils (generators, It can also be used for motors).

  Furthermore, the epoxy resin composition of the present embodiment includes, for example, potting resins such as flyback transformers, ignition coils, and AC capacitors, transparent sealing resins such as LEDs, detectors, emitters, and photocouplers, film capacitors, and impregnation of various coils. It can also be used as an insulating sealing resin used in the field of weak electricity such as resin.

  The epoxy resin composition of the present embodiment can also be used for various FRP molded products, various coating materials, adhesives, decorative materials, and the like as other uses that do not necessarily require a laminate or insulation.

  EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not construed as being limited to the following examples.

  In the following Examples and Comparative Examples, the physical properties of the obtained epoxy resin compositions and the cured products thereof were measured and evaluated as follows.

(1) Viscosity of Epoxy Resin Composition The viscosity of the epoxy resin composition was measured using a dynamic viscoelasticity measuring device (ARES manufactured by TA Instruments Inc.) with a 25 mmφ aluminum plate and a distance between plates of 0.05 mm, furnace Measurement was performed at an internal temperature of 30 ° C.

  The viscosity increase ratio of the epoxy resin composition was such that the epoxy resin composition was allowed to pass for 7 hours at room temperature (15 to 27 ° C.) in a glass screw bottle with a lid with respect to the viscosity immediately after the preparation of the epoxy resin composition. It was set as the ratio of the viscosity of the subsequent epoxy resin composition.

[Viscosity evaluation immediately after compounding]
○: An epoxy resin composition having a viscosity immediately after blending of 5 Pa · s or less.
X: An epoxy resin composition having a viscosity immediately after preparation exceeding 5 Pa · s.

    [Evaluation of thickening ratio]

A: An epoxy resin composition having a viscosity increase ratio of 2 times or less.
○: An epoxy resin composition having a thickening ratio of more than 2 times and 3 times or less.
X: An epoxy resin composition having a thickening ratio exceeding 3 times.

(2) Heat-resistant coloring property test A predetermined amount of the sample (epoxy resin composition) was mixed in a beaker with a stirrer, and the dissolved inert gas in the epoxy resin composition was degassed in vacuum. Thereafter, the epoxy resin composition was poured into a silicone mold having a 50 mm square and a depth of 3 mm, precured in a hot air dryer at 100 ° C. for 3 hours, and then postcured at 150 ° C. for 2 hours to obtain a cured product. .

The obtained cured product was heated at 150 ° C. for 1000 hours. About the cured product before heating and after heating, the light transmittance is measured with a spectrophotometer [Spectrophotometer UV-3100 manufactured by Shimadzu Corporation], and from the surface reflectance calculated from the refractive index measured separately. The light transmittance at 400 nm corresponding to 1 mm thickness was determined. And the maintenance factor of the light transmittance by heat processing was calculated | required from the following formula.

(3) UV coloring resistance test (light resistance test)
The cured product obtained in the same manner as in the heat resistant colorability test was placed in a test furnace of Dainippon Plastics I Super UV Tester SUV-W11, and the wavelength range was 55 ° C./50 RH%. UV irradiation was performed for 120 hours with light of 295 to 450 nm (having the highest intensity peak at 360 to 380 nm) at an irradiation surface light intensity of 68 mW / cm ² .

About the cured product before irradiation and after irradiation, the light transmittance is measured with a spectrophotometer [Spectrophotometer UV-3100 manufactured by Shimadzu Corporation], and from the surface reflectance calculated from the refractive index measured separately. The light transmittance at 400 nm corresponding to 1 mm thickness was determined. And the maintenance factor of the light transmittance by UV irradiation was calculated | required from the following formula.

(4) Crack resistance test A predetermined amount of the sample (epoxy resin composition) was mixed in a beaker with a stirrer, and dissolved inert gas in the epoxy resin composition was degassed in vacuum. Thereafter, the epoxy resin composition was poured into a surface-mounted light emitting diode, precured at 100 ° C. for 3 hours in a hot air dryer, and then postcured at 150 ° C. for 2 hours to obtain a cured product. Further, a light emitting diode sealed with the cured product was obtained.

  This light-emitting diode is heated at 60 ° C. and 60% RH for 144 hours, and then heated in a reflow furnace (Furukawa Electric Co., Ltd., XNB-738PC (C)) at a maximum temperature of 260 ° C. and a temperature range of 230 to 260 ° C. for 40 seconds. Was applied three times.

  The above operation was performed 10 samples for each cured product, and the crack resistance was evaluated as follows from the occurrence of peeling and cracks in the cured product of the light-emitting diode after thermal history.

[Evaluation of crack resistance]
○: Hardened product of 0 samples with no peeling or cracking Δ: Hardened material with 1 sample of peeling or cracking ×: Hardened material with 2 or more samples of peeling or cracking

  In the examples and comparative examples, the following components were used as raw materials for the epoxy resin composition.

(1) Acid anhydride (A)
Cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride [Mitsubishi Gas Chemical Co., Ltd., hereinafter also referred to as “H-TMAn”. ]
A mixture of hexahydrophthalic anhydride and methylhexahydrophthalic anhydride [manufactured by Shin Nippon Rika Co., Ltd., MH700G, hereinafter also referred to as “phthalic anhydride mixture”. ]
・ Methylhexahydrophthalic anhydride [manufactured by Shin Nippon Rika Co., Ltd., MH, hereinafter also referred to as “MeHHPA”. ]

(2) Epoxy resin (B)
(2-1) Alicyclic epoxy resin compound / 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate [Daicel Co., Ltd., CEL2021P]

(2-2) Glycidyl ester type epoxy resin compound / hexahydrophthalic acid diglycidyl ester [manufactured by Sakamoto Pharmaceutical Co., Ltd., SR-HHPA]

(2-3) Linear epoxy resin compound / hexane-1,6-diglycidyl ether [manufactured by Sakamoto Pharmaceutical Co., Ltd., SR-16H]

(3) Antioxidant / hindered phenol antioxidant: AO-50 [manufactured by ADEKA Corporation, hereinafter also referred to as “AO-50”. ]
Hindered phenol antioxidant: 2,6-bis (1,1-dimethylethyl) -4-methylphenol [manufactured by Kanto Chemical Co., Ltd., hereinafter also referred to as “BHT”. ]

(4) Curing accelerator, quaternary phosphonium bromide salt [manufactured by San Apro, hereinafter referred to as “U-CAT5003”. ]

(5) Yttrium aluminum oxide doped with fluorescent substance / cerium [Y ₃ Al ₅ O ₁₂ : Ce, yellow phosphor. ]

[Example 1]
H-TMAn [Mitsubishi Gas Chemical Co., Ltd.] 79.0 parts by mass, a mixture of hexahydrophthalic anhydride and methylhexahydrophthalic anhydride [manufactured by Shin Nippon Rika Co., Ltd. MH700G] 21.0 parts by mass, alicyclic Epoxy resin compound [3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate: Daicel Corporation CEL2021P] 172 parts by mass, glycidyl ester type epoxy resin compound hexahydrophthalic acid diglycidyl ester [ SR-HHPA from Sakamoto Yakuhin Kogyo Co., Ltd. 73.9 parts by mass, 2.8 parts by mass of hindered phenol antioxidant AO-50 (manufactured by ADEKA Corporation), and sunapro which is a bromide salt of quaternary phosphonium "U-CAT5003" 0.80 parts by mass, mixed with epoxy A resin composition was obtained. Measurement of physical properties and evaluation of the obtained epoxy resin composition and cured product thereof were performed by the above-described methods. The results are shown in Table 1.

[Examples 2 to 16 and Comparative Examples 1 to 9]
An epoxy resin composition was obtained in the same manner as in Example 1 except that the types and ratios of the raw material components were changed as shown in Tables 1 to 3. Measurement of physical properties and evaluation of the obtained epoxy resin composition and cured product thereof were performed by the above-described methods. The results are shown in Tables 1-3.

  The following was found from Tables 1 to 3 above.

  The acid anhydride (A) and the epoxy resin (B) are contained, and the acid anhydride (A) contains 30 to 90% by mass of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride. The epoxy resin (B) contains 30 to 90% by mass of the alicyclic epoxy resin compound, contains the glycidyl ester type epoxy resin compound, and the blending equivalent ratio of the acid anhydride and the epoxy resin is 0.4 to 0.4%. An epoxy resin composition in the range of 0.7 has a low viscosity after preparation, a low rate of thickening at room temperature, excellent workability, and a cured product can be obtained without adding a curing accelerator. It was found that the curability was good. Further, it was found that the cured product was colorless and transparent, excellent in crack resistance, and little colored under prolonged light irradiation and heating at 150 ° C. for 1000 hours.

  In particular, the content of H-TMAn in the acid anhydride (A) is controlled to 30 to 90% by mass, the content of the alicyclic epoxy resin compound in the epoxy resin (B) is controlled to 30 to 90% by mass, By controlling the content of the glycidyl ester type epoxy resin compound in the epoxy resin (B) to 10 to 60% by mass and setting the compounding equivalent ratio of the acid anhydride and the epoxy resin to 0.4 to 0.7, heat resistance is improved. It has been found that a cured product can be obtained that is more excellent in colorability and UV color resistance, better in workability of the epoxy resin composition, and more excellent in crack resistance.

Claims (9)

Containing an acid anhydride (A) and an epoxy resin (B),
(A) The acid anhydride (A) contains 30 to 90% by mass of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride,
(B) The epoxy resin (B) contains 30 to 90% by mass of the alicyclic epoxy resin compound, contains the glycidyl ester type epoxy resin compound,
(C) The epoxy resin composition whose compounding equivalent ratio of the acid anhydride and epoxy resin represented by following formula (1) is the range of 0.4-0.7.
Compounding equivalent ratio of acid anhydride and epoxy resin = (X + Y) / Z (1)
X: Number of functional groups of acid anhydride group contained in acid anhydride (A) Y: Number of functional groups of carboxyl group contained in acid anhydride (A) Z: Number of functional groups of epoxy group contained in epoxy resin (B) Number of functional groups   The epoxy resin composition of Claim 1 whose content of the glycidyl ester type epoxy resin compound in an epoxy resin (B) is 10-60 mass%.   The glycidyl ester type epoxy resin compound is at least one selected from the group consisting of adipic acid diglycidyl ester, long-chain dibasic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester and hexahydrophthalic acid diglycidyl ester, Item 3. The epoxy resin composition according to Item 1 or 2.   The epoxy resin composition according to any one of claims 1 to 3, wherein the alicyclic epoxy resin compound is 3,4-epoxycyclohexenylmethyl-3 ', 4'-epoxycyclohexenecarboxylate.   Furthermore, the epoxy resin composition as described in any one of Claims 1-4 which contains 0.1-5 mass% of hindered phenolic antioxidants.   Furthermore, the epoxy resin composition as described in any one of Claims 1-5 which contains 0.01-5 mass% of phosphorus hardening accelerators.   Furthermore, it contains a fluorescent material capable of emitting fluorescence by absorbing at least a part of light emitted from a light emitting element having a main emission peak wavelength of 550 nm or less. The epoxy resin composition described in 1.   The epoxy resin hardened | cured material obtained by hardening | curing the epoxy resin composition as described in any one of Claims 1-7.   The light emitting diode by which the light emitting element is sealed with the epoxy resin hardened | cured material of Claim 8.