JP2003221490A - Resin composition for use in encapsulation of light emitting diode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition suitable for encapsulation of a light emitting diode that has excellent light transmission just after hardened (a first stage light transmission), even if after UV radiation for a long time (resistance to UV light), and after usage at a high temperature for a long time (heat resistance). <P>SOLUTION: The resin composition for use in encapsulation of the light emitting diode comprises the following components (A)-(E). (A) a compound having an alicyclic structure bonded with at least one epoxy group and containing at least two epoxy groups in a molecule, (B) a saturated aliphatic compound containing an alicyclic structure and a carboxylic acid anhydride group, (C) a quarternary phosphonium salt based accelerator, (D) a phenol based antioxidant represented by general formula (1) (wherein n represents an integer of 1-22), and (E) at least one kind of antioxidants selected from a liquid phosphorous based antioxidant and a sulfur based antioxidant represented by general formula (2) (wherein m is an integer of 10-22). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resin composition for encapsulating a light emitting diode.

[0002]

2. Description of the Related Art In recent years, light emitting diodes which emit light of short wavelength such as blue light and ultraviolet light, and white light emitting diodes in which a phosphor is combined with these light emitting diodes have been put into practical use. These light emitting diodes are required to have a high transmittance for blue light to ultraviolet light, and to have a low transmittance due to heat generated during operation or short wavelength light from the light emitting diode chip. And as a resin composition for encapsulating a light emitting diode, a resin composition containing a non-aromatic epoxy resin as an active ingredient has been proposed, and specifically, 3,4-epoxycyclohexylmethyl-3,4.
-A resin composition for encapsulating a light-emitting diode, which comprises epoxycyclohexanecarboxylate and methylhexahydrophthalic anhydride as active ingredients has been disclosed (Japanese Patent Laid-Open No. 2000-2000).
-196151).

[0003]

DISCLOSURE OF THE INVENTION As a resin composition for encapsulating a light emitting diode, the present inventors have found that 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and methylhexahydrophthalic anhydride. When a cured product of an epoxy resin composition containing as an active ingredient was examined, it was revealed that the cured product was colored when stored at a high temperature (150 ° C.) and had insufficient heat resistance. The object of the present invention is to provide excellent light transmittance immediately after curing (initial transmittance), excellent light transmittance even when irradiated with ultraviolet light for a long time (ultraviolet light resistance), and to be used for a long time at high temperature. Even if it provides a resin composition suitable for light emitting diode encapsulation which is excellent in light transmittance (heat resistance).

[0004]

The present invention includes the following (A)-
A resin composition for encapsulating a light-emitting diode, which comprises the component (E). (A) A compound containing an alicyclic structure to which at least one epoxy group is bonded, and containing at least two epoxy groups in the molecule (B) Saturated containing an alicyclic structure and a carboxylic acid anhydride group Aliphatic compound (C) Quaternary phosphonium salt-based curing accelerator (D) Phenol-based antioxidant represented by the following general formula (1) (In the formula, n represents an integer of 1 to 22) (E) At least 1 selected from a liquid phosphorus antioxidant and a sulfur antioxidant represented by the following general formula (2).
Kinds of antioxidants (In the formula, m represents an integer of 10 to 22)

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The component (A) of the present invention is a compound containing an alicyclic structure to which at least one epoxy group is bonded and containing at least two epoxy groups in the molecule. Among them, a compound having substantially no carbon-carbon double bond in the molecule is preferable. Further, a homopolymer of the compound or a polymer obtained by polymerizing two or more different compounds is also the component (A) of the present invention.

Specific components (A) include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and ε-caprolactone-modified 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarbochelate. , Bis (3,4-epoxycyclohexyl) adipate, 1,2: 8,9-
Examples include diepoxy limonene. As the component (A), for example, Celoxide (registered trademark, Daicel Chemical Industries, Ltd.) 2021 (main component is 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate), 2021P (3,4-). Commercially available products such as epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate as a main component, Epolide (registered trademark, Daicel Chemical Industries, Ltd.) GT301, and GT401 may be used as they are as the component (A).
As the component (A), two or more kinds of the component (A) may be used in combination.

As the component (A), among others, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, ε-caprolactone-modified 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarbochelate, Bis (3,4-epoxycyclohexyl) adipate is preferred, especially 3,4-epoxycyclohexylmethyl-3,4-
Epoxycyclohexanecarboxylate and bis (3,4-epoxycyclohexyl) adipate are preferred.

As long as the cured product of the resin composition for encapsulating a light emitting diode does not impair the initial transparency, heat resistance and ultraviolet light resistance, "a resin containing an alicyclic structure having at least one epoxy group bonded, and The component (A) may contain an epoxy resin which is different from the "compound containing at least two epoxy groups in the molecule" and which does not substantially contain a carbon-carbon double bond in the molecule. Specific examples of the epoxy resin that may be contained as the component (A) include a heterocyclic epoxy resin; a hydrogenated aromatic epoxy resin; a glycidyl ether obtained from an aliphatic alcohol and epihalohydrin; an aliphatic carboxylic acid and epihalohydrin. And a glycidyl ester obtained from an alicyclic carboxylic acid and epihalohydrin; and a spiro ring-containing epoxy resin.

Here, as the heterocyclic epoxy resin,
Examples thereof include hydantoin-type epoxy resin and triglycidyl isocyanurate. Examples of hydrogenated aromatic epoxy resins include hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, and hydrogenated phenol novolac type epoxy resin. Examples thereof include resins, hydrogenated cresol novolac type epoxy resins, hydrogenated biphenyl type epoxy resins and the like. Examples of the glycidyl ether obtained from an aliphatic alcohol and epihalohydrin include butyl glycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, cyclohexane dimethanol diglycidyl ether, polypropylene glycol diglycidyl ether, Examples include trimethylolpropane triglycidyl ether. Examples of the glycidyl ester obtained from the aliphatic carboxylic acid and epihalohydrin include, for example, neodecanoic acid glycidyl ester, and the glycidyl ester obtained from the alicyclic carboxylic acid and epihalohydrin includes, for example, diglycidyl hexahydrophthalate. Examples thereof include esters.

The component (B) of the present invention is a saturated aliphatic compound containing an alicyclic structure and a carboxylic acid anhydride group,
Preferably, a carboxylic acid anhydride group is bonded to the alicyclic structure. Specifically, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, norbornane-2,3-dicarboxylic anhydride, methylnorbornane-2,3-dicarboxylic anhydride, the following formula (3) Examples thereof include saturated aliphatic compounds. (B)
As the component, two or more kinds of component (B) may be used in combination. The content of the component (B) in the resin composition of the present invention is usually 0.5 to 5 with respect to the total amount of 1 equivalent of the epoxy groups contained as the component (A).
It is about 1.5 equivalents, preferably about 0.8 to 1.2 equivalents.

The component (C) of the present invention is a quaternary phosphonium salt-based curing accelerator, and examples thereof include tetra-n-butylphosphonium bromide, tetra-n-butylphosphonium benzotriazolate and tetra-n-butyl. Phosphonium tetrafluoroborate, tetra-n-butylphosphonium tetraphenylborate, tetraphenylphosphonium bromide, methyltriphenylphosphonium bromide, ethyltriphenylphosphonium bromide, ethyltriphenylphosphonium iodide, ethyltriphenylphosphonium acetate, n-butyltriphenyl Examples thereof include phosphonium bromide, benzyltriphenylphosphonium chloride, tetraphenylphosphonium tetraphenylborate and the like.
Among them, tetra-n-butylphosphonium bromide is preferable as the component (C). The content of the component (C) in the resin composition of the present invention is usually about 0.1 to 10 parts by weight, preferably 0.3 to 10 parts by weight, relative to 100 parts by weight of the acid anhydride of the component (B). It is about 3 parts by weight.

The component (D) of the present invention has the following general formula (1): (In the formula, n represents an integer of 1 to 22) and is a phenolic antioxidant. Among them, the carbon number n is 8 to 18
Some phenolic antioxidants are suitable. The content of the component (D) in the resin composition of the present invention is usually about 0.03 to 3 parts by weight based on 100 parts by weight of the total of the components (A), (B) and (C), It is preferably about 0.1 to 1 part by weight.

Component (E) of the present invention is at least one antioxidant selected from liquid phosphorus antioxidants and sulfur antioxidants represented by the following general formula (2). (In the formula, m represents an integer of 10 to 22) The content of the component (E) in the resin composition of the present invention is usually 10 in total of the components (A), (B) and (C).
It is about 0.03 to 3 parts by weight, preferably about 0.1 to 1 part by weight, relative to 0 parts by weight.

The liquid phosphorus antioxidant as the component (E) is
It is a phosphorus-based antioxidant that is liquid at 25 ° C., and it is preferable that the agent is liquid because it tends to be uniformly mixed with the resin composition of the present invention. Examples of the liquid phosphorus-based antioxidant include the following general formulas (4) to (11)

[0015] (In the formula, R ¹ represents an alkyl group having about 8 to 22 carbon atoms)

[0016] (In the formula, k represents an integer of about 0 to 3, and R ² has 8 carbon atoms.
It represents an alkyl group having about 22 carbon atoms, preferably an alkyl group having about 10 carbon atoms. )

[0017] (In the formula, R ³ represents an alkyl group having about 8 to 13 carbon atoms)

[0018] (In the formula, R ⁴ represents an alkyl group having about 8 to 22 carbon atoms)

[0019]

[0020] (In the formula, R ⁵ represents an alkyl group having about 8 to 22 carbon atoms)

[0021] (In the formula, R ⁶ represents an alkyl group having about 8 to 22 carbon atoms)

[0022] (In the formula, R ⁷ represents an alkyl group having about 8 to 22 carbon atoms) and the like, and a liquid phosphorus antioxidant and the like,
Especially, the liquid phosphorus-based antioxidant represented by the general formula (4) is preferable.

The sulfur antioxidant as the component (E) is a compound represented by the general formula (2), in which m is 12
Sulfur antioxidants of -19 are preferred.

The resin composition for encapsulating a light-emitting diode of the present invention contains a releasing agent, a silane coupling agent, and a stress-reducing agent as long as the transparency, heat resistance and ultraviolet light resistance of the obtained cured product are not impaired. Additives such as agents, fillers, plasticizers, defoamers, thixotropic agents, dyes, light scattering agents, and ultraviolet absorbers may be included.

The present invention is a resin composition for encapsulating a light emitting diode, which contains the above components (A) to (E) as essential components. The method for producing the resin composition of the present invention includes, for example,
Examples include a method in which the components (A) to (E) and any components are blended, mixed with a kneader and kneaded to produce.
At the time of mixing, the component (D) and / or the component (E) may be dissolved in a small amount of a solvent such as alcohol, acetone, or toluene and then mixed, and after the solvent used at this time is mixed, It is preferable to volatilize and remove by heating and / or reduced pressure.

The cured product of the present invention is a cured product obtained by curing the resin composition for encapsulating a light emitting diode thus obtained, and the initial transmittance of the cured product is usually about 70% or more, preferably It is about 75% or more. Here, the initial transmittance means that after the resin composition is cured and the cured product obtained by cooling to room temperature and having a thickness of 2 mm is cooled,
The transmittance when irradiated with light having a wavelength of 370 nm in the thickness direction. A cured product having a transmittance of 70% or more is preferable because it has excellent light transmittance.

The cured product of the present invention is excellent in heat resistance and ultraviolet light resistance. Here, the heat resistance test is a test in which a cured product prepared to have a thickness of 2 mm is stored at 150 ° C. for 72 hours, and then the transmittance is measured when the light having a wavelength of 370 nm is irradiated in the thickness direction. When the transmittance is about 50% or more,
Coloring is prevented (excellent light transmittance) and heat resistance is excellent, which is preferable. In addition, the ultraviolet light resistance test means that a cured product prepared to have a thickness of 2 mm is 340 n under the condition of 40 ° C. and 50% RH.
This is a test for measuring the transmittance when light having a light amount of 0.55 W / m ² at m is irradiated for 300 hours and then light having a wavelength of 370 nm is irradiated in the thickness direction. When the transmittance is about 50% or more, coloring is prevented (excellent light transmittance) and ultraviolet light resistance is excellent, which is preferable.

The light emitting diode of the present invention is obtained by sealing the light emitting diode element with the cured product described in the present invention. As a method of manufacturing a light emitting diode, for example,
A method of attaching a light emitting diode element and, if necessary, an electrode such as a lead wire, and subsequently sealing and curing by a molding method such as transfer molding or casting with the resin composition of the present invention; a light emitting diode element or the like Is mounted on a substrate, and the resin composition of the present invention is sealed therein. Further, the light emitting diode of the present invention may be encapsulated with a light emitting body such as a phosphor different from the light emitting diode element.

[0029]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. Parts and% in the examples mean weight basis unless otherwise specified.

Example 1 <Production Example 1 of resin composition for encapsulating light emitting diode> (B)
Methyl hexahydrophthalic anhydride (HN-
5500, manufactured by Hitachi Chemical Co., Ltd., 100 parts, and 1 part of tetra-n-butylphosphonium bromide (manufactured by Hokuko Kagaku Kogyo Co., Ltd., TBP-BB) as a component (C) were mixed to prepare a curing agent. Hardening agent / 127 parts, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate ((A) component, Daicel Chemical Industries, Ltd. Celoxide (registered trademark) 2021P, epoxy equivalent = 134) 100 parts Were uniformly mixed to obtain a resin mixture of components (A) to (C). The compounding amount of this curing agent is such that the epoxy groups of the component (A) and the acid anhydride groups of the component (B) are equivalent. With respect to the resin mixture of the components (A) to (C) thus obtained, the following formula (12) is used as the component (D). 0.25 parts of a phenolic antioxidant represented by (E)
The following formula (13) as a component 0.25 parts of a liquid phosphorus antioxidant represented by is mixed to obtain a liquid light emitting diode encapsulating resin composition.

<Production Example 1 of Cured Product> A mold in which two glass plates and a spacer having a thickness of 2 mm were combined was preheated to 100 ° C. The resin composition obtained in the previous section was cast into the mold, and 1
Curing was carried out under the conditions of 00 ° C. × 2 hours + 120 ° C. × 2 hours to obtain a cured product having a thickness of 2 mm. The physical properties of the obtained cured product were evaluated as follows, and the results are shown in Table 1.

<Method for measuring physical properties of cured product> (I) Initial transmittance After curing the resin composition and cooling it to room temperature, a transmission spectrum of a cured product having a thickness of 2 mm is V-560 manufactured by JASCO Corporation. It measured with the spectrophotometer and calculated | required the transmittance | permeability in wavelength 370nm. The cured product was stored in a cool and dark place until measurement, and measured within 1 day after cooling to room temperature. (II) Transmittance after storage at high temperature The cured product was stored in a blast drying oven at 150 ° C. for 72 hours, and then the transmittance at a wavelength of 370 nm was measured by the same method as in (I) above. (III) Using a ATLAS Ci4000 xenon weatherometer, the transmittance cured product after irradiation with ultraviolet light was subjected to 340 under conditions of 40 ° C. and 50% RH.
After irradiating with light having a light amount of 0.55 W / m ² for 300 hours, the wavelength is 370 nm by the same method as in (I) above.
The transmittance was measured.

(Example 2 and Comparative Examples 1 to 6) Example 2
As the component (E) of the above, instead of the liquid phosphorus antioxidant represented by the above formula (13), the following formula (14) A resin composition for encapsulating a light emitting diode and a cured product thereof were produced in the same manner as in Example 1 except that the sulfur-based antioxidant represented by was used, and the results are summarized in Table 1. Comparative Examples 1 to 4
Is the compounding ratio of the component (D) or the component (E) shown in Table 1, and according to Example 1, a resin composition for encapsulating a light emitting diode and a cured product thereof are produced, and the results are summarized in Table 1. It was Further, in Comparative Example 5, instead of the component (E), the following formula (1
5) A phosphorus-based antioxidant that is solid at 25 ° C. represented by the following formula (1) is used instead of the component (E) in Comparative Example 6.
6) A resin composition for encapsulating a light emitting diode and a cured product thereof were produced in accordance with Example 1 except that the sulfur-based antioxidant represented by was used, and the results are summarized in Table 1.

[0034]

[Table 1] (I) The initial transmittance of 70% or more was represented by O, and the initial transmittance of less than 70% was represented by X. (II) The transmittance after storage at high temperature (150 ° C. × 72 hours) of 50% or more was represented by ◯, and less than 50% was represented by x. (III) Transmittance after irradiation with ultraviolet light (30% light at a light amount of 0.55 W / m ² at 340 nm)
Irradiation for 0 hours) 50% or more is represented by O, and less than 50% is represented by X.

[0035]

EFFECTS OF THE INVENTION The cured product of the resin composition for encapsulating a light emitting diode of the present invention has excellent light transmittance (initial transmittance) immediately after curing, and has a light transmittance (UV resistance) even when it is irradiated with ultraviolet light for a long time. In addition to being excellent in light resistance, it is also excellent in light transmission (heat resistance) even when used at high temperature for a long time. Further, since the resin composition of the present invention gives a cured product having such excellent properties, it is used as a transparent encapsulating material for electric and electronic parts such as light emitting diodes, a transparent coating material, a transparent adhesive, a glass substitute material, etc. Can be used for

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09K 3/10 C09K 3/10 L 5F041 Z 15/08 15/08 15/12 15/12 H01L 23/29 H01L 33/00 N 23/31 23/30 F 33/00 (72) Inventor Toshiyuki Hasegawa 3-98 Kasugashinaka, Konohana-ku, Osaka-shi, Osaka Sumitomo Chemical Co., Ltd. F-term (reference) 4H017 AA04 AA31 AB08 AC03 AC07 AD06 AE05 4H025 AA14 AA29 4J002 CD021 EJ066 EV047 EW067 EW087 FD076 FD077 GP00 4J036 AJ09 DA04 DB21 DD07 FA10 FA12 JA07 4M109 AA01 BA01 EC04 EC01 GA01 DA01 EC44 EC04 EC11

Claims (8)

[Claims] 1. A resin composition for encapsulating a light emitting diode, which comprises the following components (A) to (E). (A) A compound containing an alicyclic structure to which at least one epoxy group is bonded, and containing at least two epoxy groups in the molecule (B) Saturated containing an alicyclic structure and a carboxylic acid anhydride group Aliphatic compound (C) Quaternary phosphonium salt-based curing accelerator (D) Phenol-based antioxidant represented by the following general formula (1) (In the formula, n represents an integer of 1 to 22) (E) At least 1 selected from a liquid phosphorus antioxidant and a sulfur antioxidant represented by the following general formula (2).
Kinds of antioxidants (In the formula, m represents an integer of 10 to 22) 2. The component (A) is 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and / or bis (3,4-epoxycyclohexyl) adipate, according to claim 1. The resin composition described. 3. The component (B) is hexahydrophthalic anhydride,
Methyl hexahydrophthalic anhydride, norbornane-2,
3-dicarboxylic acid anhydride, methylnorbornane-2,3
-Dicarboxylic acid anhydride and the following formula (3) At least 1 selected from saturated aliphatic compounds represented by
The compound according to claim 1, which is a compound of a kind.
The resin composition according to. 4. The resin composition according to any one of claims 1 to 3, wherein the component (C) is tetra-n-butylphosphonium bromide. 5. The resin composition according to any one of claims 1 to 4, wherein n in the general formula (1) is 8 to 18. 6. A liquid phosphorus antioxidant is represented by the following general formula (4): (In formula, R < ¹ > represents a C8-C22 alkyl group) It is an antioxidant and is represented, The resin composition in any one of Claims 1-5 characterized by the above-mentioned. 7. A cured product obtained by curing the resin composition according to claim 1. 8. A light-emitting diode containing the cured product according to claim 7.