JP2015152643A - Thermosetting resin composition for light reflector, light reflector and light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosetting resin composition for light reflector with a high reflectance, which hardly deteriorates due to heat.SOLUTION: The thermosetting resin composition includes an epoxy resin, a hardening agent and a white pigment. The epoxy resin includes a chemical compound expressed by the following formula (1) (where, R1 represents a hydrogen atom or methyl group; R2 represents a divalent organic group; R3-R10 represent a molecular chain including a hydrogen atom, a substituent group or an epoxy group respectively).

Description

  The present invention relates to a thermosetting resin composition for a light reflector suitable for producing a light reflector (reflector), a light reflector molded from the thermosetting resin composition for a light reflector, and the light. The present invention relates to a light emitting device including a reflector.

  Conventionally, a light reflector that is attached to a light emitting element such as an LED (Light Emitting Diode) and reflects light is known. A polyamide resin is generally used as a resin for molding the light reflector. However, although the light reflector can be molded at low cost from the polyamide resin, the heat discoloration of the light reflector is not good. For this reason, when combined with a high-output light-emitting element that emits a large amount of heat, the reflectance of the light reflector tends to decrease significantly. Therefore, a technique using an epoxy resin as a resin other than the polyamide resin has been developed.

  For example, Patent Document 1 discloses a light reflecting resin composition using an epoxy resin. This document describes a resin composition having excellent light reflectivity.

International Publication No. 2008/059856

  However, the light reflector is required to have higher heat discoloration and light reflectance.

  Specifically, the light reflector is not easily deteriorated even when it is exposed to heat generated when the light emitting element is mounted or used, and thus it is required that a high reflectance can be maintained. Yes.

  Furthermore, when the resin composition used for the production of the light reflector is a thermosetting resin composition, the fluidity at the time of molding hardly changes even after long-term storage, that is, excellent storage stability. That is also sought.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a thermosetting resin composition for a light reflector that has high light reflectivity, high heat discoloration, and excellent storage stability. .

The thermosetting resin composition for a light reflector according to the present invention is a thermosetting resin composition used for producing a light reflector,
Containing an epoxy resin, a curing agent, and a white pigment;
The epoxy resin contains a compound represented by the following formula (1).

(In the formula, R 1 represents a hydrogen atom or a methyl group, R 2 represents a divalent organic group, and R 3 to R 10 each independently represents a hydrogen atom, a substituent, or an epoxy group-containing molecular chain.)
In the thermosetting resin composition for light reflectors according to the present invention, the compound represented by the formula (1) is preferably a compound represented by the following formula (2).

In the thermosetting resin composition for light reflectors according to the present invention, the epoxy resin further contains tris- (2,3-epoxypropyl) -isocyanurate,
The tris- (2,3-epoxypropyl) -isocyanurate has an optical isomer ratio such that the total amount of (2R, 2R, 2S) and (2S, 2S, 2R) is (2R, 2R, It is preferable that it is 4 times or more with respect to the total amount of (2R) body and (2S, 2S, 2S) body.

  In the thermosetting resin composition for light reflectors according to the present invention, it is preferable that the epoxy resin further contains a compound represented by the following formula (3).

  In the thermosetting resin composition for light reflectors according to the present invention, the epoxy group equivalent of the epoxy resin is preferably within a range of 215 to 250.

  In the thermosetting resin composition for light reflectors according to the present invention, the content of the white pigment is preferably 10% by mass or more.

  In the thermosetting resin composition for light reflectors according to the present invention, the curing agent preferably contains an acid anhydride having a melting point of 35 ° C. or higher.

  In the thermosetting resin composition for light reflectors according to the present invention, the curing agent is cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, hexahydrophthalic anhydride, and 4- It is preferable to contain one or more substances selected from the group consisting of methylhexahydrophthalic anhydride.

  In the thermosetting resin composition for light reflectors according to the present invention, it is preferable to further contain an antioxidant.

  The light reflector according to the present invention is preferably molded from the thermosetting resin composition for a light reflector.

  In the light reflector according to the present invention, it is preferable that the amount of decrease in light reflectance by a heating test under the conditions of a heating temperature of 150 ° C. and a heating time of 1000 hours is 17 point percent or less.

  The light emitting device according to the present invention preferably includes a light emitting element and the light reflector.

  According to the present invention, it is possible to obtain a thermosetting resin composition for a light reflector, a light reflector, and a light emitting device that have high reflectivity and are not easily deteriorated by heat.

It is sectional drawing which shows a light-emitting device provided with the light reflector in one Embodiment of this invention.

  The thermosetting resin composition for light reflectors according to the present embodiment (hereinafter referred to as a resin composition) is used for producing the light reflector 1. This resin composition contains an epoxy resin, a curing agent, and a white pigment. The epoxy resin contains a compound represented by the following formula (1).

(In the formula, R 1 represents a hydrogen atom or a methyl group, R 2 represents a divalent organic group, and R 3 to R 10 each independently represents a hydrogen atom, a substituent, or an epoxy group-containing molecular chain.)
For this reason, since the reaction at the time of preservation | save is suppressed, the resin composition which concerns on this embodiment does not change the fluidity | liquidity at the time of shaping | molding after a long-term preservation | save, ie, is excellent in storage stability.

  Furthermore, the light reflector obtained by molding the resin composition according to this embodiment has high heat discoloration.

  In this resin composition, the compound represented by the formula (1) is also preferably a compound represented by the following formula (2).

  The resin composition further contains tris- (2,3-epoxypropyl) -isocyanurate, and the tris- (2,3-epoxypropyl) -isocyanurate has an optical isomer ratio of (2R, The total amount of the (2R, 2S) body and the (2S, 2S, 2R) body is 4 times or more than the total amount of the (2R, 2R, 2R) body and the (2S, 2S, 2S) body. Is also preferable.

  This resin composition preferably further contains a compound represented by the following formula (3).

  In this resin composition, it is also preferable that the epoxy group equivalent of the epoxy resin is in the range of 215 to 250.

  In this resin composition, the content of the white pigment is preferably 10% by mass or more.

  In this resin composition, the curing agent preferably contains an acid anhydride having a melting point of 35 ° C. or higher.

  In this resin composition, the curing agent is selected from the group consisting of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, hexahydrophthalic anhydride, and 4-methylhexahydrophthalic anhydride. It is preferable to contain one or more substances.

  This resin composition preferably further contains an antioxidant.

  The resin composition according to this embodiment will be described in more detail.

  Examples of the divalent organic group represented by R2 in formula (1) include a substituted or unsubstituted arylene group such as a phenylene group, a group having a structure in which a substituted or unsubstituted arylene group and a carbon atom or a carbon chain are bonded to each other. It is done. Examples of the carbon atom or carbon chain include alkylene groups such as methylmethylene group and dimethylmethylene group, and carbonyl groups.

The divalent organic group of R2 preferably includes a phenylene group bonded to a glycidyloxy group bonded to R2 of the formula (1). In this case, the glycidyloxy group and the phenylene group constitute a glycidyloxyphenyl group. Further, in order to improve the light-reflective heat discoloration, R2 has two arylene groups, and a methylene group (—CH ₂ —) is included in the carbon atom or carbon chain interposed between the arylene groups. Preferably not.

  Examples of the divalent organic group represented by R2 include the following structures (inside square brackets).

  Although it does not specifically limit as a substituent of R3-R10 in Formula (1), For example, hydrocarbon groups, such as a lower alkyl group, another organic group, etc. are mentioned. Examples of the molecular chain containing an epoxy group of R3 to R10 include the following structures (inside square brackets).

  Although an epoxy resin contains the compound represented by the said Formula (1), an epoxy resin may further contain compounds other than the compound represented by the said Formula (1).

  The epoxy resin may contain a compound generally used as a molding material. Examples of this compound include epoxidized phenol and aldehyde novolak resins such as phenol novolak type epoxy resins and orthocresol novolak type epoxy resins. Moreover, diglycidyl ethers such as bisphenol A, bisphenol F, bisphenol S, and alkyl-substituted biphenol can be used. In addition, glycidylamine type epoxy resins obtained by reaction of polyamines such as diaminodiphenylmethane and isocyanuric acid with epichlorohydrin, linear aliphatic epoxy resins obtained by oxidizing olefinic bonds with peracids such as peracetic acid, and alicyclic rings Group epoxy resins and the like. These may be used alone or in combination of two or more. The epoxy resin is preferably colorless or light yellow and relatively uncolored. The epoxy resin preferably contains a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, and diglycidyl isocyanurate as a compound other than the compound represented by the above formula (1).

  The ratio of the compound represented by the above formula (1) with respect to the total amount of the epoxy resin is not particularly limited, but is preferably 30% by mass or more. Thereby, the resin composition is excellent in storage stability. Furthermore, the light reflector obtained by molding the resin composition has high heat discoloration. The ratio of the compound represented by the above formula (1) with respect to the total amount of the epoxy resin is more preferably 40% by mass or more, further preferably 50% by mass or more, still more preferably 60% by mass or more, Preferably it is 70 mass% or more, More preferably, it is 80 mass% or more. The upper limit of the ratio of the compound represented by the above formula (1) with respect to the total amount of the epoxy resin is not particularly limited, but may be 95% by mass or less. Of course, all of the epoxy resin may be a compound represented by the above formula (1).

  In the present embodiment, the compound represented by the formula (1) is preferably a compound represented by the formula (2). Specific examples of the compound represented by the above formula (2) include NC6500 (trade name, manufactured by Nippon Kayaku Co., Ltd.), VG3010L (trade name, manufactured by Printec Co., Ltd.) and the like.

  Moreover, the epoxy resin may contain an epoxy resin oligomer. An epoxy resin oligomer is an oligomerized compound having an epoxy group. The epoxy resin oligomer preferably has a viscosity at 100 to 150 ° C. in the range of 100 to 2500 mPa · s. This viscosity is particularly preferred in transfer molding. If the melt viscosity of the resin composition after kneading is low and the fluidity is too high, the air vent of the molding die may be blocked, and air and volatile components may remain in the die cavity. Air and volatile components remaining in the cavity cause appearance defects such as molding voids and weld marks. As the number of moldings increases, the monomer component remaining on the surface of the cured product adheres to the molding die and contaminates the die. As a result of the deposit of monomer deposits on the mold, there is a problem that the releasability of the molded product from the mold deteriorates. On the other hand, by using an oligomer having a specific viscosity as described above, it is possible to increase the melt viscosity of the resin composition after kneading and decrease the fluidity. Further, by using such an oligomer, it is possible to reduce residual monomer components that cause mold contamination. As a result, problems that occur when the melt viscosity is low can be avoided, the transfer moldability of the resin composition can be improved, and a molded product with an excellent appearance can be obtained.

  Prior to the preparation of the resin composition, the epoxy resin oligomer is prepared by blending at least a compound having an epoxy group and a curing agent, and if necessary, a curing accelerator. As the compound having an epoxy group, the curing agent, and the curing accelerator, the same epoxy resin as described above, and the same curing agent and curing accelerator described later can be used.

  More specifically, the epoxy resin oligomer is, for example, an active group (an acid anhydride group) in the curing agent capable of reacting the epoxy group-containing compound and the curing agent with the epoxy group with respect to 1 equivalent of the epoxy group. Or a hydroxyl group) can be obtained through a step of kneading until the mixture becomes a clay state. It is preferable to provide a step of subsequently aging the obtained clay-like kneaded material at a temperature in the range of 25 to 60 ° C. for 1 to 6 hours. Moreover, when using a hardening accelerator, it is preferable to mix | blend so that it may become 0.005-0.05 mass part with respect to 100 mass parts of total of the compound and epoxy resin which have an epoxy group. In an epoxy resin oligomer, you may react in the grade which the epoxy group in the compound which has an epoxy group does not cure completely.

  As for an epoxy resin oligomer, it is more preferable that the viscosity in 100 degreeC exists in the range of 100-2500 mPa * s. Thereby, it becomes possible to adjust the burr length at the time of molding shorter. If the viscosity of the epoxy resin oligomer is less than 100 mPa · s, burrs are likely to occur during transfer molding. On the other hand, when the viscosity exceeds 2500 mPa · s, the fluidity at the time of molding tends to be low, and the moldability tends to be poor. The “viscosity” may be a value obtained by measurement using an ICI cone plate viscometer. The epoxy resin oligomer can be suppressed or stopped from increasing in viscosity by being pulverized until the particle size becomes 1 mm or less and stored in an environment at a temperature of 0 ° C. or less. The pulverization method of the epoxy resin oligomer can be performed by an appropriate method such as pulverization with a ceramic mortar.

  The epoxy resin oligomer may be an oligomer of a compound represented by the above formula (1). Moreover, the mixture of the oligomer of the compound represented by the said Formula (1) and the oligomer of the compound which has an epoxy group other than that may be sufficient as an epoxy resin oligomer. That is, the compound represented by the above formula (1) contained in the epoxy resin may be oligomerized in the resin composition.

  The ratio of the compound represented by the oligomerized formula (1) to the whole compound represented by the formula (1) is preferably 20% by mass or less, more preferably 15% by mass or less, and 13 It is particularly preferable that the content is not more than mass%.

  A part of the epoxy groups of the compound represented by the formula (1) may be sealed with alcohol. That is, the compound represented by the formula (1) may include a compound in which some epoxy groups are sealed with alcohol.

  It is preferable that the epoxy equivalent of the compound represented by Formula (1) is in the range of 215 to 250. In this case, the heat-reflective color change of the light reflector is particularly high. This is because when the epoxy equivalent is 250 or less, the crosslink density is increased, the heat discoloration of the light reflector is improved, and when the epoxy equivalent is 215 or more, an unreacted epoxy in the light reflector. This is presumed to be because the group hardly remains.

  The epoxy equivalent of the compound represented by the formula (1) is adjusted by, for example, oligomerizing a part of the compound or sealing a part of the epoxy group of the compound with alcohol.

  It is also preferred that the epoxy resin contains tris- (2,3-epoxypropyl) -isocyanurate. Also in this case, the light reflector has high heat discoloration.

  This tris- (2,3-epoxypropyl) -isocyanurate has an optical isomer ratio such that the total amount of (2R, 2R, 2S) and (2S, 2S, 2R) is (2R, 2R, 2R) and (2S, 2S, 2S) are 4 times or more of the total amount.

  Tris- (2,3-epoxypropyl) -isocyanurate is a compound represented by the following structural formula. Another name for tris- (2,3-epoxypropyl) -isocyanurate is triglycidyl isocyanurate.

Tris- (2,3-epoxypropyl) -isocyanurate has three asymmetric carbons. Each asymmetric carbon is a carbon constituting an epoxy ring. There are (2R, 2R, 2R) and (2S, 2S, 2S) isomers as tris- (2,3-epoxypropyl) -isocyanurate with all three asymmetric carbon configurations. . The (2R, 2R, 2R) isomer refers to (2R, 2R, 2R) -tris- (2,3-epoxypropyl) -isocyanurate. The (2S, 2S, 2S) isomer refers to (2S, 2S, 2S) -tris- (2,3-epoxypropyl) -isocyanurate.

  Further, as tris- (2,3-epoxypropyl) -isocyanurate having only one of the three asymmetric carbons having different optical anisotropy, (2R, 2R, 2S) and (2S, 2S, 2R) There is a body. The (2R, 2R, 2S) isomer refers to (2R, 2R, 2S) -tris- (2,3-epoxypropyl) -isocyanurate. The (2S, 2S, 2R) isomer refers to (2S, 2S, 2R) -tris- (2,3-epoxypropyl) -isocyanurate.

  The structural formula of (2R, 2R, 2S) -tris- (2,3-epoxypropyl) -isocyanurate, which is a (2R, 2R, 2S) isomer, is shown below.

  The structural formula of (2S, 2S, 2R) -tris- (2,3-epoxypropyl) -isocyanurate, which is a (2S, 2S, 2R) isomer, is shown below.

  The structural formula of (2R, 2R, 2R) -tris- (2,3-epoxypropyl) -isocyanurate, which is a (2R, 2R, 2R) isomer, is shown below.

  The structural formula of (2S, 2S, 2S) -tris- (2,3-epoxypropyl) -isocyanurate, which is a (2S, 2S, 2S) isomer, is shown below.

In tris- (2,3-epoxypropyl) -isocyanurate, the (2R, 2R, 2R) isomer and the (2S, 2S, 2S) isomer are the (2R, 2R, 2S) isomer and (2S, The melting point is higher than that of 2S, 2R). This tris- (2,3-epoxypropyl) -isocyanurate, which is considered to be due to the configuration, is usually mixed with optical isomers. At this time, the melting point is measured at a plurality of locations (for example, two locations) by mixing optical isomers having different melting points as described above. The melting point is measured, for example, by DSC (differential scanning calorimetry).

By the way, the racemic mixture of the (2R, 2R, 2R) isomer and the (2S, 2S, 2S) isomer is generally referred to as β-type. The β type is known to give a high melting point type crystal of about 150 ° C. This is because the two enantiomers form a pair of strong six molecular hydrogen bonds and a crystal lattice having a high degree of hydrogen bond with other molecular lattices. A mixture of (2R, 2R, 2S) isomer and (2S, 2S, 2R) isomer is generally called α-type. The α type does not have a crystal structure like the β type, and therefore has a relatively low melting point. The melting point of α-type is about 100 ° C. In addition, although α type and β type are classified due to crystallinity, in this specification, for convenience, at least one of (2R, 2R, 2R) and (2S, 2S, 2S) is included. Is referred to as α type, and at least one of (2R, 2R, 2S) and (2S, 2S, 2R) isomers is referred to as β type.

  In tris- (2,3-epoxypropyl) -isocyanurate, the amount of isomers showing a high-temperature melting point increases when shifted to the β-type with many (2R, 2R, 2R) and (2S, 2S, 2S) isomers. The melting point as a whole is high. On the other hand, when shifting to the α type having many (2R, 2R, 2S) and (2S, 2S, 2R) isomers, the amount of isomers showing a low-temperature melting point increases, and the melting point as a whole decreases.

  Usually, the ratio of α-form to β-form present in tris- (2,3-epoxypropyl) -isocyanurate obtained by the conventional method is 3: 1. That is, the ratio of the total amount of (2R, 2R, 2S) body and (2S, 2S, 2R) body to the total amount of (2R, 2R, 2R) body and (2S, 2S, 2S) body is 3 It is.

  Heretofore, tris- (2,3-epoxypropyl) -isocyanurate has been desired to have a high melting point type. The high melting point type tris- (2,3-epoxypropyl) -isocyanurate has a relatively high β-type content, and not only has a high melting point but also a low solubility in various solvents compared to the α-type and the like. . Therefore, when used as a one-component reactive mixture as a cross-linking agent for heterogeneous compounds or reactive polymers, the reaction does not proceed until it is forcibly heated and cured, and is considered useful for electrical and electronic materials. It was done.

On the other hand, in the thermosetting resin composition for light reflectors, it is important that curing does not proceed at a low temperature such as a storage temperature, but the raw material melts well in order to improve light reflectivity and moldability. It is also important to exhibit fluidity at relatively low heating temperatures. When the ratio of the high melting point type tris- (2,3-epoxypropyl) -isocyanurate is large, when the materials are mixed, the high melting point type is not uniformly mixed but a melting residue is generated, and the reflectance There is a risk of lowering. For example, the resin composition can be produced by kneading, but at a temperature at which the kneading is low, there is a possibility that the melted residue may be generated without being sufficiently dissolved. In order to increase the mixing property of tris- (2,3-epoxypropyl) -isocyanurate, it is conceivable to increase the mixing temperature, but when the temperature is increased, the curing reaction proceeds during mixing, and the fluidity and Storage stability may be reduced. Further, if the ratio of the high melting point type tris- (2,3-epoxypropyl) -isocyanurate is large, the fluidity when heated is lowered, and the moldability may be lowered. Here, the melting point of tris- (2,3-epoxypropyl) -isocyanurate having an α-type: β-type ratio of 3: 1 is 100 to 115 ° C. For this reason, kneading at about 100 ° C. causes undissolved residue and often causes black spots. Therefore, the total amount of the (2R, 2R, 2S) body and the (2S, 2S, 2R) body is 4 with respect to the total amount of the (2R, 2R, 2R) body and the (2S, 2S, 2S) body. Tris- (2,3-epoxypropyl) -isocyanurate that is twice or more is included. This ratio is higher than the ratio 3 of α type to β type obtained by the conventional method. Therefore, the ratio of the high melting point type tris- (2,3-epoxypropyl) -isocyanurate is lowered, and the melting point of the epoxy resin is lowered. Therefore, the melt residue at the time of kneading can be suppressed and the reflectivity can be enhanced, the fluidity at the time of heating can be increased, and the moldability can be improved. That is, a black spot can be eliminated by using tris- (2,3-epoxypropyl) -isocyanurate having a high α-type ratio.

  The ratio of optical isomers in tris- (2,3-epoxypropyl) -isocyanurate can be expressed as a molar ratio which is the ratio of the amounts of substances. The ratio of optical isomers in tris- (2,3-epoxypropyl) -isocyanurate may be expressed as a mass ratio. This is because they are optical isomers, and the types and amounts of atoms are the same, so that the molecular weights of the compounds themselves are equal.

  In tris- (2,3-epoxypropyl) -isocyanurate, the (2R, 2R, 2S) isomer and the (2S, 2S) isomer with respect to the total amount of (2R, 2R, 2R) isomer and (2S, 2S, 2S) isomer , 2R) The higher the ratio of the total amount of the body, the better. Thereby, while being able to improve reflectivity, the fluidity | liquidity at the time of shaping | molding increases more. For example, the total amount of (2R, 2R, 2S) and (2S, 2S, 2R) isomers is 5 times the total amount of (2R, 2R, 2R) and (2S, 2S, 2S) isomers The above is preferable. The magnification (ratio) is more preferably 6 times or more, more preferably 7 times or more, still more preferably 8 times or more, still more preferably 9 times or more, still more preferably 10 times or more, and more preferably 15 times or more. Even more preferable, 19 times or more is even more preferable. However, if an optically pure compound is to be obtained, the production may not be easy. Therefore, in tris- (2,3-epoxypropyl) -isocyanurate, the total amount of (2R, 2R, 2S) and (2S, 2S, 2R) isomers is (2R, 2R, 2R) and ( For example, it may be 999 times or less of the total amount of (2S, 2S, 2S) bodies. This magnification (ratio) may be 99 times or less, 50 times or less, or 25 times or less.

  The ratio of (2R, 2R, 2S) isomer and (2S, 2S, 2R) isomer contained in tris- (2,3-epoxypropyl) -isocyanurate is not particularly limited. For example, this ratio may be 1: 4 to 4: 1. In this case, tris- (2,3-epoxypropyl) -isocyanurate can be obtained more easily. Alternatively, an equal amount of a mixture having a ratio of 1: 1 may be used. A mixture of equal amounts of enantiomers is called a racemic mixture.

  The ratio of (2R, 2R, 2R) isomer and (2S, 2S, 2S) isomer contained in tris- (2,3-epoxypropyl) -isocyanurate is not particularly limited. For example, this ratio may be 1: 4 to 4: 1. In this case, tris- (2,3-epoxypropyl) -isocyanurate can be obtained more easily. Alternatively, an equal amount of a mixture having a ratio of 1: 1 may be used. A mixture of equal amounts of enantiomers is called a racemic mixture.

  Tris- (2,3-epoxypropyl) -isocyanurate having a high content ratio of (2R, 2R, 2S) and (2S, 2S, 2R) is tris- (2,3-epoxypropyl) -isocyanurate. Can be obtained by adjusting the ratio by an appropriate method and separating and purifying the isomers to increase the ratio. As an isomer separation method, an appropriate method such as a solvent separation method, a recrystallization method, a column chromatography method, or the like can be used. Here, as described above, it is only necessary to purify the α-form so that the amount of the substance is four times or more that of the β-form, and it may not be required until the isomers are completely separated. The separation of diastereomers can be performed relatively easily than the separation of enantiomers.

  Specific examples of tris- (2,3-epoxypropyl) -isocyanurate include TEPIC-L (trade name, manufactured by Nissan Chemical Co., Ltd.).

  When the epoxy resin contains tris- (2,3-epoxypropyl) -isocyanurate, the compound represented by the above formula (1) with respect to the total amount of the epoxy resin and tris- (2,3-epoxypropyl) -isocyanurate The total ratio of is not particularly limited, but is preferably 30% by mass or more, more preferably 40% by mass or more, further preferably 50% by mass or more, still more preferably 60% by mass or more, and 70% by mass. The above is more preferable, and 80% by mass or more is still more preferable. The total ratio of the compound represented by the above formula (1) and tris- (2,3-epoxypropyl) -isocyanurate with respect to the total amount of the epoxy resin is not particularly limited, but is 95% by mass or less. May be. Of course, the epoxy resin may contain only the compound represented by the above formula (1) and tris- (2,3-epoxypropyl) -isocyanurate.

  When the epoxy resin contains tris- (2,3-epoxypropyl) -isocyanurate, the total of the compound represented by formula (1) and tris- (2,3-epoxypropyl) -isocyanurate The proportion of tris- (2,3-epoxypropyl) -isocyanurate is preferably in the range of more than 0% by mass and 95% by mass or less, and in the range of 5% by mass to 50% by mass. If present, it is more preferable.

  It is also preferable that the epoxy resin contains, for example, a compound represented by the above formula (3). In this case, the light reflector has heat discoloration.

  Specific examples of the compound represented by the formula (3) include 2021P (trade name, manufactured by Daicel Corporation).

  Moreover, when an epoxy resin contains the compound represented by the said Formula (3), in the said Formula (3) with respect to the sum total of the compound represented by the Formula (1), and the compound represented by the said Formula (3). The ratio of the compound represented is preferably in the range of more than 0% by mass and 95% by mass or less, and more preferably in the range of 5% by mass to 50% by mass.

  The resin composition contains a curing agent. It is preferable that a hardening | curing agent contains the acid anhydride which has 35 degreeC or more melting | fusing point. Examples of the acid anhydride include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, tetrahydrophthalic anhydride, methyl nadic anhydride, nadic anhydride, glutaric anhydride, dimethyl glutaric anhydride, and anhydrous Diethylglutaric acid, succinic anhydride, methyltetrahydrophthalic anhydride, cyclohexanetricarboxylic anhydride, hexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, cyclohexane-1,2,4-tricarboxylic acid-1,2 -Anhydrides and the like.

  The curing agent contains one or more substances selected from the group consisting of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, hexahydrophthalic anhydride, and 4-methylhexahydrophthalic anhydride. It is preferable. In this case, the melt viscosity of the resin composition can be increased. Moreover, since the curing time of the resin composition can be shortened, the molding efficiency can be improved.

  Cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride has a solid type and a highly viscous liquid type at 35 ° C. The difference in type is thought to originate from the ratio of isomers. Any type of cyclohexanetricarboxylic acid anhydride may be used. In particular, it is preferable to use a cyclohexanetricarboxylic anhydride that is solid at 35 ° C.

  The cyclohexane tricarboxylic acid anhydride is specifically a compound represented by the following formula.

  Specifically, hexahydrophthalic anhydride is a compound represented by the following formula.

  Specifically, 4-methylhexahydrophthalic anhydride is a compound represented by the following formula.

  The curing agent further includes cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, hexahydrophthalic anhydride, and acid anhydrides other than 4-methylhexahydrophthalic anhydride, isocyanuric acid derivatives, and phenol. One or more compounds selected from the group consisting of system compounds may be contained.

  Examples of the isocyanuric acid derivatives include 1,3,5-tris (1-carboxymethyl) isocyanurate, 1,3,5-tris (2-carboxyethyl) isocyanurate, 1,3,5-tris (3-carboxyl). Propyl) isocyanurate, 1,3-bis (2-carboxyethyl) isocyanurate and the like.

  Examples of phenolic compounds include phenols such as phenol, cresol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol, and / or naphthols such as α-naphthol, β-naphthol, dihydroxynaphthalene, and formaldehyde. And a novolak type phenol resin obtained by condensation or cocondensation with a compound having an aldehyde group such as benzaldehyde and salicylaldehyde under an acidic catalyst. Moreover, the phenol aralkyl resin synthesized from phenols and / or naphthols and dimethoxyparaxylene or bis (methoxymethyl) biphenyl may be mentioned. Moreover, aralkyl type phenol resins, such as biphenylene type phenol aralkyl resin and naphthol aralkyl resin, are mentioned. Moreover, dicyclopentadiene type phenol resins, such as dicyclopentadiene type phenol novolak resin and dicyclopentadiene type naphthol novolak resin, synthesized by copolymerization of phenols and / or naphthols with dicyclopentadiene are exemplified. Moreover, a triphenylmethane type phenol resin, a terpene modified phenol resin, paraxylylene and / or a metaxylylene modified phenol resin, a melamine modified phenol resin, and a cyclopentadiene modified phenol resin are mentioned. Furthermore, the phenol resin obtained by copolymerizing 2 or more types of said phenol type hardening | curing agent is mentioned.

  The total content of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, hexahydrophthalic anhydride, and 4-methylhexahydrophthalic anhydride relative to the total amount of the curing agent is not particularly limited. However, it is preferable to adjust in the range of 5% by mass or more and 100% by mass or less. From the viewpoint of balance between cost and performance, the content is preferably in the range of 25% by mass to 75% by mass.

  The compounding ratio of the epoxy resin and the curing agent is such that the active group (acid anhydride group or hydroxyl group) in the curing agent capable of reacting with the epoxy group is 0.5 to 1 with respect to 1 equivalent of the epoxy group in the epoxy resin. The ratio is preferably 5 equivalents. When the active group is less than 0.5 equivalent, the curing rate of the resin composition is slowed, and the glass transition temperature of the light reflector molded from the resin composition is lowered, thereby obtaining a sufficient elastic modulus. There may not be. Moreover, when the said active group exceeds 1.2 equivalent, the intensity | strength after hardening may reduce. This ratio is more preferably 0.7 to 1.2 equivalent when no epoxy resin oligomer is used.

  When the epoxy resin contains only an epoxy resin oligomer, or when the epoxy resin contains an epoxy resin oligomer and a compound other than that, other preferable ranges can be set for the compounding ratio of the epoxy resin and the curing agent. In this case, the compounding ratio of the epoxy resin and the curing agent is such that the active group (acid anhydride group or hydroxyl group) in the curing agent capable of reacting with the epoxy group is 0 with respect to 1 equivalent of the epoxy group in the epoxy resin oligomer. It is preferable that it is a ratio which will be 0.5-0.7 equivalent. When the active group is less than 0.5 equivalent, the curing rate of the resin composition is slowed, and the glass transition temperature of the light reflector molded from the resin composition is lowered, thereby obtaining a sufficient elastic modulus. There may not be. Moreover, when the said active group exceeds 0.7 equivalent, the intensity | strength after hardening may reduce. This ratio is more preferably a ratio that makes 0.6 to 0.7 equivalents. In addition, when the epoxy resin contains an epoxy resin oligomer, the number of equivalents of the curing agent is calculated by assuming that the total amount of epoxy groups contained in each of the compound contained in the epoxy resin oligomer and the other compound is 1 equivalent. And the sum total of the active group which can react with the said epoxy group contained in a hardening | curing agent and a hardening | curing agent is converted as an equivalent number with respect to an epoxy group.

  The resin composition may contain an appropriate compound as a curing accelerator. Examples of the curing accelerator include tertiary amines such as 1,8-diaza-bicyclo (5,4,0) undecene-7, triethylenediamine and tri-2,4,6-dimethylaminomethylphenol. Further, imidazoles such as 2-ethyl-4methylimidazole and 2-methylimidazole can be mentioned. In addition, phosphorus compounds such as triphenylphosphine, tetraphenylphosphonium tetraphenylborate, tetra-n-butylphosphonium-o, o-diethylphosphorodithioate, and tetra-n-butylphosphonium-tetraphenylborate are exemplified. Moreover, a quaternary ammonium salt and organometallic salts are mentioned. Furthermore, derivatives of these compounds are mentioned. These may be used alone or in combination. The curing accelerator particularly preferably contains a tertiary amine, an imidazole, or a phosphorus compound.

  It is preferable that the content rate of a hardening accelerator is 0.01-8.0 mass% with respect to the epoxy resin whole quantity, and it is more preferable that it is 0.1-3.0 mass%. When the content of the curing accelerator is 0.01% by mass or more, a sufficient curing acceleration effect can be obtained. Moreover, when the content rate of a hardening accelerator will be 8.0 mass% or less, it can suppress more that discoloration generate | occur | produces from a resin composition and a light reflector occurs.

  The resin composition contains a white pigment. The white pigment imparts high light reflectivity to the light reflector molded from the resin composition. .

  The white pigment preferably contains, for example, one or more materials selected from the group consisting of alumina, magnesium oxide, antimony oxide, titanium oxide, zirconium oxide, and inorganic hollow particles. . Examples of the inorganic hollow particles include sodium silicate glass, aluminum silicate glass, borosilicate soda glass, and shirasu. From the viewpoint of thermal conductivity and light reflection characteristics, at least alumina or magnesium oxide may be used, or a combination thereof may be used. In order to improve light reflectivity, it is preferable to use titanium oxide.

The white pigment preferably has a center particle size in the range of 0.1 to 50 μm. When the center particle size is less than 0.1 μm, the particles tend to aggregate and the dispersibility tends to deteriorate. On the other hand, if the center particle size exceeds 50 μm, the light reflection characteristics of the cured product may not be sufficiently obtained.

  It is preferable that the compounding quantity of a white pigment is 10 mass% or more with respect to the whole resin composition. Thereby, the reflectance of the light reflector shape | molded from a resin composition can be made high. It is preferable that the compounding quantity of a white pigment is 80 mass% or less with respect to the whole resin composition. The blending amount of the white pigment is preferably in the range of 10% by mass to 80% by mass, and more preferably in the range of 15% by mass to 80% by mass with respect to the entire resin composition.

  The resin composition may further contain a filler. In this case, the reflectivity of the light reflector molded from the resin composition is further increased, and the shape stability of the light reflector is further increased. In addition, the filler can increase the thermal conductivity of the light reflector. Thereby, discoloration, deterioration, etc. due to heat of the light reflector are further suppressed.

  The filler preferably contains at least one of inorganic particles or organic particles. The outer shape of the filler is preferably 0.01 to 500 μm from the viewpoint of light reflectivity and handleability. If it is smaller than 0.01 μm, the filler may be dispersed unevenly. If it is larger than 500 μm, the surface of the reflector is roughened, and the reflectance is lowered.

  The inorganic particles preferably contain, for example, one or more materials selected from the group consisting of inorganic glass, silica, alumina, calcium carbonate, barium carbonate, calcium silicate, and nickel carbonate. The inorganic particles particularly preferably contain silica. For example, the organic particles preferably contain an acrylic resin, and particularly preferably contain a crosslinked (meth) acrylic resin or a crosslinked styrene-acrylic resin.

  It is preferable that the particles contained in the filler are hollow particles. In the hollow particles, the light passing through the outer shell is reflected by the hollow portion. In order to increase the reflectance, it is preferable that the difference in refractive index between the portion constituting the hollow particles and the gas existing therein is large. The gas present inside the hollow particles is usually air, but may be an inert gas such as nitrogen or argon, or may be a vacuum.

  The hollow particles are preferably particles (single hollow) containing one closed cell inside the particles. In this case, the inner diameter of the hollow particles (the diameter of the closed cells) is more preferably 0.05 to 100 μm and more preferably 0.1 to 50 μm from the viewpoint of light reflectivity. Outside this range, the reflection efficiency deteriorates. The hollow particles are also preferably porous particles (multi-hollow) enclosing a plurality of closed cells inside the particles. When light is absorbed by the outer shell of the hollow particles, the ultraviolet rays that reach the inside of the hollow particles are reduced, and the reflectance at the hollow portion is reduced. Therefore, those that do not absorb much ultraviolet rays are preferable. Moreover, since a hollow part is destroyed by heat processing and a reflective characteristic will be lost when a hollow part is lose | eliminated, a thing with high heat resistance is preferable.

  Therefore, the filler is, for example, one or more materials selected from the group consisting of single hollow silica, single hollow crosslinked acrylic resin, single hollow crosslinked styrene-acrylic resin, and multiple hollow crosslinked acrylic resin. Can be contained.

  Further, the filler may not contain hollow particles. In this case, the filler can contain, for example, spherical silica.

  Spherical silica preferably has a high pressure strength. If the pressure strength is high, the damage of the particles during the kneading / molding of the resin composition is reduced, so that the light reflectance of the molded body is increased. Furthermore, the higher the pressure resistance, the higher the bending strength of the molded body. The pressure strength is preferably 80 MPa or more, more preferably 100 MPa or more, further preferably 130 MPa or more, and further preferably 150 MPa or more.

  The total amount of the filler and the white pigment is preferably in the range of 10% by mass to 85% by mass with respect to the entire resin composition. If the total blending amount is less than 10% by mass, the light reflection characteristics of the cured product may not be sufficiently obtained. On the other hand, when the total blending amount exceeds 85% by mass, the moldability of the resin composition is deteriorated, and the production of the light reflector tends to be difficult.

  A coupling agent may be added to the resin composition. Examples of the coupling agent include a silane coupling agent and a titanate coupling agent. Moreover, an epoxy silane type, an amino silane type, a cationic silane type, a vinyl silane type, an acrylic silane type, a mercapto silane type, and a composite system thereof may be mentioned. The type and treatment conditions of the coupling agent are not particularly limited, and an appropriate method such as a method of adding the resin composition as it is or a method of adding it in advance with a filler or a white pigment may be applied. Good. The blending amount of the coupling agent is preferably 5% by mass or less with respect to the resin composition.

  The resin composition preferably contains an antioxidant. Thereby, the fall of the reflectance of a light reflector can be suppressed, and a high reflectance can be maintained longer. Moreover, the storage stability of a resin composition can be improved by containing antioxidant.

  Examples of the antioxidant include a phenol-based antioxidant, a thioether-based antioxidant, and a phosphorus-based antioxidant. These may be used alone or in combination. Among these antioxidants, it is preferable to use a phosphorus-based antioxidant. Examples of phosphorus antioxidants include 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4,4′-butylidenebis (3-methyl-6-tert-butylphenyl-di-). Tridecyl phosphite), diphenylisodecyl phosphite and the like. Specific examples of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4,4′-butylidenebis (3-methyl-6-tert-butylphenyl-di-tridecyl phosphite) HCA (trade name, manufactured by Sanko Co., Ltd.). It is also preferable to use hindered phenol as an antioxidant.

  It is preferable that the content rate of antioxidant is 1-20 mass parts with respect to 100 mass parts of epoxy resins, More preferably, it is 3-18 mass parts. If the content of the antioxidant is less than 1 part by mass, a sufficient antioxidant effect may not be obtained, and if it exceeds 20 parts by mass, discoloration may be seen in the resulting colored product. When the amount of the antioxidant falls within the above range, the reflectance can be made more difficult to decrease. The content of the antioxidant is more preferably 5 parts by mass or more with respect to 100 parts by mass of the epoxy resin.

  The resin composition preferably contains a fluorescent brightening agent. Thereby, the reflectance of the light reflector shape | molded from a resin composition can be raised.

Examples of the fluorescent brightening agent include benzoxazole compounds, benzoxazole derivatives, coumarin derivatives, imidazole derivatives, and stilbene derivatives. Among these, it is desirable to use a benzoxazole derivative. The content of the optical brightener is preferably 0.001% by mass or more and 1% by mass or less. When the amount of the fluorescent brightening agent is within this range, the reflectance can be increased efficiently.

  The resin composition preferably contains a release agent. By containing a mold release agent, the mold release property can be improved, so that the production becomes easy.

  As the mold release agent, waxes such as fatty acids, fatty acid metal salts, and minerals that are generally used for thermosetting resins can be used. In particular, fatty acid-based and fatty acid metal salt-based materials excellent in heat discoloration can be suitably used.

  Examples of the release agent include aliphatic ether, stearic acid, zinc stearate, aluminum stearate, calcium stearate and the like. These mold release agents may be used independently and may use 2 or more types together.

  A mold release agent can be mix | blended in 0.001-1 mass% with respect to the resin composition whole quantity. When the blending amount of the release agent is within this range, it is possible to further achieve both good release properties and excellent appearance, and it is possible to improve the reflectivity of the light reflector molded from the resin composition. .

  Other components can be added to the resin composition as necessary. For example, various additives such as an ion scavenger, a reinforcing material, and a stabilizer may be added.

  The resin composition can be obtained as a solid material such as granular or powder. That is, the resin composition can be configured as a dry resin composition. Here, the dry type means a solid in a temperature range of 30 ° C. or lower, and can be processed into a granular shape by pulverization or extrusion pellet processing. When the resin composition becomes solid, storage stability and handling properties can be improved. It is preferable that the resin composition which became solid has storage shape stability at the temperature of 50 degrees C or less. Thereby, handling property and workability can be further enhanced.

  The resin composition is manufactured by blending each component and mixing it sufficiently uniformly using a mixer, a blender, etc., and then preparing and granulating it with a kneader, extruder, etc. capable of being heated and pressurized. be able to. The preparation means and conditions of the resin composition are not particularly limited. By using a solid raw material, it can be easily mixed by a powder mixing apparatus. As a kneader, a pressure kneader, a heat roll, an extruder, or the like may be used. In the granulation, the bulk body may be formed and then pulverized and sized. Moreover, you may granulate suitably. The resin composition is obtained in a granular form, a powder form, a pellet form, or the like.

  The resin composition can be prepared by a powder mixing method. As a general method of powder mixing method, after stirring and mixing various components of a predetermined blending amount sufficiently uniformly with a mixer, etc., kneading using a mixing roll, an extruder, a kneader, a roll and an extruder, etc. A method of cooling and pulverizing the obtained kneaded material can be mentioned. The kneading type is not particularly limited, but melt kneading is preferable. The conditions for melt-kneading may be appropriately determined according to the type and amount of components used, and are not particularly limited. For example, it is preferable to melt knead in the range of 15 to 100 ° C. for 5 to 40 minutes. Furthermore, it is more preferable to melt-knead in the range of 20 to 100 ° C. for 10 to 30 minutes. If the temperature at the time of melt kneading is less than 15 ° C., it is difficult to melt and knead each component, and the dispersibility tends to decrease. On the other hand, when the temperature is higher than 100 ° C., the resin composition has a high molecular weight and the resin composition may be cured. Further, if the melt kneading time is less than 5 minutes, the burr length tends not to be effectively suppressed. If the melt kneading time is longer than 40 minutes, the resin composition increases in molecular weight, and before molding. The resin composition may be cured.

  Here, when preparing a resin composition, it is preferable to premix the compound used as a hardening | curing agent with a part or all of an epoxy resin. By this preliminary mixing, the dispersibility of the curing agent with respect to the base resin can be further enhanced. As a result, it is possible to more effectively suppress the occurrence of mold and package contamination due to the dispersion failure of the curing agent. Preliminary mixing may be performed between the total amount of the epoxy resin and the compound used as the curing agent, but sufficient effects can be obtained even by premixing with a part of the epoxy resin. In that case, it is preferable that the quantity of the epoxy resin used for preliminary mixing shall be 10-50 mass% with respect to the total amount of components. The premixing method is not particularly limited as long as the compound used as the curing agent can be dispersed in the epoxy resin. For example, a method in which both components are stirred for 0.5 to 20 hours under a temperature condition of room temperature to 220 ° C. From the viewpoint of dispersibility and efficiency, the stirring time is preferably 1 to 10 hours, more preferably 3 to 6 hours under a temperature condition of 100 to 200 ° C, more preferably 150 to 170 ° C. Preheating mixing performed here, for example, weighs 100 parts by mass of an epoxy resin and 120 parts by mass of a curing agent in a container made of heat-resistant glass, and uses a heater whose medium is a fluid such as silicone oil or water. And a method such as heating in a temperature range of 35 ° C to 180 ° C. The heating method is not limited to the above method, and a known method such as thermocouple or electromagnetic wave irradiation can be used, and ultrasonic waves may be irradiated to further promote dissolution.

  The resin composition is preferably aged (aged) for the purpose of increasing the melt viscosity at the time of molding after blending and kneading the above-mentioned components. More specifically, aging is preferably performed at 0 ° C. to 30 ° C. for 1 to 72 hours. Aging is more preferably performed at 15 to 30 ° C. for 12 to 72 hours. The aging is more preferably performed at 25 to 30 ° C. for 24 to 72 hours.

  The resin composition can be molded without a solvent. Since the resin composition softens and melts by heating, the resin composition that has become liquid by heat can be molded into an appropriate shape even without a solvent. Of course, a solvent may be appropriately added in consideration of moldability. However, no solvent is preferred from the viewpoint of ease of molding.

  The resin composition is excellent in storage stability. That is, the resin composition has no significant change in the initial fluidity and the fluidity after standing for a long time. For this reason, even after the resin composition is left standing for a long period of time, a light reflector can be molded from the resin composition.

  Since the resin composition is a thermosetting resin, a cured product can be obtained under appropriate curing conditions for curing the thermosetting resin. Moreover, the molded object which consists of hardened | cured material can be obtained by heat-molding using a shaping | molding die. This molded body becomes a light reflector for a light emitting element. That is, the light reflector is manufactured by molding the resin composition.

  In manufacturing a light reflector, it can manufacture by using an appropriate shaping | molding method by using a resin composition as a material. In the case of a solid resin composition, it can be molded by a dry method. As the molding method, for example, a melt heating molding method such as an injection molding method, an injection compression molding method, or a transfer molding method can be suitably used. Among these, the transfer molding method is a preferred embodiment. By the transfer molding method, a light reflector having an excellent appearance can be obtained even if the shape is complicated.

  Resin compositions are suitable for these molding methods because they have good thermal stability during melting. The heating condition may be a condition in which the resin composition softens and flows. For example, it can be in the range of 50 to 300 ° C. Since the resin composition has high fluidity, it is easy to mold. The heating temperature is preferably in the range of 100 to 200 ° C.

If burrs are generated on the light reflector frame after molding, it is preferable to remove the burrs. The generated burrs can be removed by an appropriate method. Cutting or cutting may be used. From the viewpoint of workability, it is preferable to remove burrs by blasting. As the blast treatment, a blast treatment method used for deburring can be used. Examples of these include shot blasting, sand blasting, and glass bead blasting.

  In the light reflector molded from the resin composition, discoloration due to thermal degradation is suppressed. The light reflector can be used as a light reflector of a light emitting element such as an LED bulb. The light reflector formed from the resin composition can constitute an inexpensive light reflector having a long lifetime. In particular, the light reflector molded from the resin composition preferably has a light reflectance reduction amount of 17 point percent or less in a heating test under the conditions of a heating temperature of 150 ° C. and a heating time of 1000 hours. In this case, the heat-reflecting color of the light reflector is high. The amount of decrease in light reflectance is more preferably 15 point percent or less, and more preferably 10 point percent or less.

  In FIG. 1, an example of a light-emitting device provided with the light reflector 1 shape | molded from the resin composition is shown. The light reflector 1 is formed in a frame shape, and has a recess 2 and a hole 3 at the center. The recess 2 is provided as an inclined surface. The wall surface of the recess 2 serves as a reflecting surface that reflects light. The hole 3 is provided at the bottom of the recess 2 so as to penetrate the light reflector 1. A lead frame 4 on which the light emitting element 5 is mounted is fitted in the hole 3. The lead frame 4 may be provided with wiring for supplying electricity to the light emitting element 5. The light emitting surface side (upper part in FIG. 1) of the recess 2 is covered with a transparent cover 6. Thereby, the light emitting element 5 is protected. The cover 6 is joined to the light reflector 1 at the opening edge of the recess 2. The light reflector 1 can efficiently reflect the light emitted from the light emitting element 5. The shape of the light reflector 1 is not limited to the shape shown in FIG. 1, and can be appropriately designed in consideration of the light amount, color, directivity characteristics, and the like of the light emitting element 5 to be mounted.

[Preparation of thermosetting resin composition for light reflector]
Each component was blended according to the blending ratio shown in Table 1, sufficiently kneaded with a mixer, and then melt-kneaded under a predetermined condition with a mixing roll to obtain a kneaded product. Furthermore, the obtained kneaded material was pulverized to prepare thermosetting resin compositions for light reflectors of Examples and Comparative Examples, respectively. In addition, the unit of the compounding quantity of each component shown in Table 1 is mass%. An epoxy resin and a hardening | curing agent occupy the remainder except components other than an epoxy resin and a hardening | curing agent from the resin composition. A blank in Table 1 means that the corresponding component is not blended.

  Here, for Examples 1 to 26 and Comparative Example 1, resin components were prepared by blending each component at one time without preliminary kneading. For Comparative Example 2, preliminary kneading was performed. In the preliminary kneading, 30% of the epoxy resin and the curing agent were first kneaded at 150 ° C. for 3 hours, and then the other components were added.

  The details of the combinations of epoxy resin and curing agent in Table 1 are shown in Table 3.

  Details of the components used in each example and each comparative example are as follows.

<Epoxy resin>
* Polyfunctional epoxy resin (epoxy equivalent 222, manufactured by Nippon Kayaku, "NC6500", epoxy group sealing rate 10%, dimer content 10-12% by mass)
* Multifunctional epoxy resin (epoxy equivalent 210, manufactured by Printec, “VG3101L”, dimer content 10 mass%)
* Triglycidyl isocyanurate (epoxy equivalent 100, manufactured by Nissan Chemical Co., Ltd., “TEPIC-L”)
* Alicyclic epoxy resin (epoxy equivalent 100, manufactured by Daicel Corporation, "2021P")
<Curing agent>
* Hexahydrophthalic anhydride (“Rikacid HH” manufactured by Shin Nippon Chemical Co., Ltd.)
* 4-Methylhexahydrophthalic anhydride (“HN-7000” manufactured by Hitachi Chemical)
* 4-Methylhexahydrophthalic anhydride (“HN-7200” manufactured by Hitachi Chemical)
* 4-Methylhexahydroxyphthalic anhydride: Hexahydrophthalic anhydride = 7: 3 (New Japan Rikashi "Licacid MH-700G")
* Cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (Mitsubishi Gas Chemical "H-TMAn-S")
<Curing accelerator>
* Tetra-n-butylphosphonium-o, o-diethyl phosphorodithioate (“PX-4ET” manufactured by Nippon Chemical Co., Ltd.)
* Ethyltriphenylphosphonium bromide ("TPP-EB" manufactured by Hokuko Chemical)
<White pigment>
* Titanium oxide ("RTC-30" manufactured by Taioxide Japan)
<Filler>
* Spherical silica ("Syrosphere C-150" manufactured by Fuji Silysia)
* Hollow silica (Sumitomo 3M "S60-HS")
* Hollow silica (“iM30K” manufactured by Sumitomo 3M)
* Hollow silica (“iM16K” manufactured by Sumitomo 3M)
* Hollow silica ("Sphericel 110P8CP01" manufactured by Potters Barodini)
* Multi-hollow hollow acrylic (Sekisui Chemical "XX3133Z")
* Hollow acrylic (Sekisui Chemical "XX3134Z")
* Hollow acrylic (JSR "SX866 (A)")
* Hollow acrylic (JSR "SX8782 (D)")
<Release agent>
* Aliphatic ether ("Unitox 420" manufactured by Toyo Petrolite)
<Antioxidant>
* Hindered phenol (Adeka "AO-60")
* 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (“HCA” manufactured by Sanko)
<Fluorescent brightener>
* Benzoxazole derivative (“Kayalight” manufactured by Nippon Kayaku)
[Evaluation of thermosetting resin composition for light reflector]
<Evaluation of storage stability>
About each resin composition of an Example and a comparative example, the fluidity | liquidity after an initial stage and after leaving was evaluated according to the following procedures. The results are shown in Tables 1 and 2.

<Initial fluidity>
The compositions obtained in each Example and Comparative Example were molded under the above conditions using a spiral flow measurement mold according to ASTM D3123, and the spiral flow length was measured. The measurement temperature is 175 ° C.

<Fluidity after standing>
After notifying the composition obtained by the above for 6 months at -5 degreeC, it shape | molded on the said conditions using the spiral flow measurement metal mold | die according to ASTMD3123, and measured the spiral flow length. The measurement temperature is 175 ° C.

<Storage stability of resin composition>
According to Tables 1 and 2, the resin compositions of the examples did not undergo any significant change in the fluidity after initial and after standing despite the temperature at −5 ° C. that was easy to maintain. For this reason, each resin composition of an Example had high storage stability. On the other hand, in Comparative Example 1, the storage stability was low because the fluidity after standing was significantly reduced.

<Evaluation of light reflectivity of molded product>
Each of the resin compositions of Examples and Comparative Examples was transfer-molded under conditions of a molding die temperature of 180 ° C., a molding pressure of 6.9 MPa, and a curing time of 90 seconds, and then post-cured at 150 ° C. for 2 hours. Test pieces having a thickness of 1.0 mm were prepared. About this molded object, the light reflectance after an initial stage and a heating was measured in accordance with the following procedures. The results are shown in Table 1.

<Initial light reflectance>
About each test piece, the light reflectance in wavelength 460nm was measured using the reflectance measuring device (Nippon Denshoku SD6000). The results are shown in Table 1.

<Light reflectance after heating>
The test piece obtained by the above was left to heat, and the reflectance after the heat history was measured at a wavelength of 460 nm using a reflectance measuring device (SD6000 manufactured by Nippon Denshoku). The heating was allowed to stand at 150 ° C. for 1000 hours. This condition is a temperature condition of an acceleration test assuming a heat load in actual use. The results are shown in Tables 1 and 2.

<Reflectivity of light reflector molded from resin composition>
According to Tables 1 and 2, each resin composition of the Examples shows excellent light reflection characteristics in the initial stage and after heating. On the other hand, in Comparative Example 1, although the initial reflectance was excellent, the light reflectivity after heating was lower than that in the Example. In Comparative Example 2, the light reflectivity was low compared with the Example even at the initial stage and after heating.

<Evaluation of bending strength of molded product>
Each of the resin compositions of Examples and Comparative Examples was transfer-molded under conditions of a molding die temperature of 175 ° C., a molding pressure of 6.9 MPa, and a curing time of 120 seconds, and then post-cured at 150 ° C. for 2 hours, A test piece having dimensions of 4 mm × 10 mm × 80 mm was molded. The bending strength of this molded product was measured according to the following procedure. The results are shown in Tables 1 and 2.

<Measurement of bending strength>
The bending strength was measured according to JIS K6911. The distance between fulcrums was 64 mm, and the crosshead speed was 2 mm / min.

<About the bending strength of the molded object shape | molded from the resin composition>
According to Tables 1 and 2, the molded body of each resin composition of the example had high bending strength. In particular, when the molded bodies of the resin compositions of Examples 2, 5, 6, and 7 containing hollow silica having different pressure strengths as fillers were compared, Example 7 containing hollow silica having the lowest pressure strength was used. The bending strength of Example 5 using the hollow silica having the lowest bending strength and the highest pressure strength was high.

DESCRIPTION OF SYMBOLS 1 Light reflector 2 Recessed part 3 Hole part 4 Lead frame 5 Light emitting element 6 Cover

Claims (12)

A thermosetting resin composition used for producing a light reflector,
Containing an epoxy resin, a curing agent, and a white pigment;
The said epoxy resin contains the compound represented by following formula (1), The thermosetting resin composition for light reflectors characterized by the above-mentioned.

(In the formula, R 1 represents a hydrogen atom or a methyl group, R 2 represents a divalent organic group, and R 3 to R 10 each independently represents a hydrogen atom, a substituent, or an epoxy group-containing molecular chain.) The thermosetting resin composition according to claim 1, wherein the compound represented by the formula (1) is a compound represented by the following formula (2).

The epoxy resin further contains tris- (2,3-epoxypropyl) -isocyanurate;
The tris- (2,3-epoxypropyl) -isocyanurate has an optical isomer ratio such that the total amount of (2R, 2R, 2S) and (2S, 2S, 2R) is (2R, 2R, The thermosetting resin composition according to claim 1 or 2, wherein the thermosetting resin composition is at least four times the total amount of the (2R) body and the (2S, 2S, 2S) body. The thermosetting resin composition according to any one of claims 1 to 3, wherein the epoxy resin further contains a compound represented by the following formula (3).

  5. The thermosetting resin composition according to claim 1, wherein an equivalent of an epoxy group of the epoxy resin is within a range of 215 to 250. 6.   The thermosetting resin composition for a light reflector according to any one of claims 1 to 5, wherein the content of the white pigment is 10% by mass or more.   The thermosetting resin composition for a light reflector according to any one of claims 1 to 6, wherein the curing agent contains an acid anhydride having a melting point of 35 ° C or higher.   The curing agent contains one or more substances selected from the group consisting of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride, hexahydrophthalic anhydride, and 4-methylhexahydrophthalic anhydride The thermosetting resin composition for light reflectors according to any one of claims 1 to 7, wherein the thermosetting resin composition is for light reflectors.   The thermosetting resin composition for a light reflector according to any one of claims 1 to 8, further comprising an antioxidant agent.   A light reflector, which is molded from the thermosetting resin composition for a light reflector according to any one of claims 1 to 9.   11. The light reflector according to claim 10, wherein an amount of decrease in light reflectance by a heating test under the conditions of a heating temperature of 150 ° C. and a heating time of 1000 hours is 17 point percent or less.   A light emitting device comprising the light reflector according to claim 11 and a light emitting element.

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