JP6213270B2 - Polysilsesquioxane encapsulant composition for UV-LED and use of solvent therefor - Google Patents

Description

  The present invention relates to a polysilsesquioxane-based encapsulant composition for UV-LED and the use of a solvent therefor.

  The polysilsesquioxane-based sealing material composition is used for sealing an element included in a UV-LED.

  Use of a solvent for a polysilsesquioxane-based encapsulant composition for UV-LEDs, particularly an encapsulant composition suitable for encapsulating a device that emits light in the UV-C region (200-280 nm) provide.

The present invention includes the inventions described in [1] and [2] below.
[1] Use of the following solvent a as a solvent for a polysilsesquioxane-based encapsulant for UV-LED, wherein the cured product has a light transmittance at 260 nm of 65% or more;
[2] A polysilsesquioxane encapsulant composition for UV-LED, comprising a polysilsesquioxane encapsulant and the following solvent a.
<Solvent a>
A solvent having an ester bond and / or an ether bond, having no hydroxy group, and having a boiling point under 1 atm of 100 ° C. or higher and 200 ° C. or lower

  The present invention provides a polysilsesquioxane-based encapsulant composition suitable for encapsulating devices that emit light in the ultraviolet region (particularly the UV-C region) and the use of a solvent therefor.

It is a ultraviolet-ray-transmittance measurement result of the hardened | cured material obtained in Example 1. FIG.

  Hereinafter, the present invention will be described in detail.

<Polysilsesquioxane-based sealing material>
In the present invention, as the polysilsesquioxane-based encapsulant, for example, Amax Co., Ltd. website “polysilsesquioxane T-resin” <URL: http://www.azmax.co.jp/cnt_catalog_chemical/ and polysilsesquioxane described in pdf / attach_20110517_135825.pdf> and the like.

（式（１）中、Ｒ^１はそれぞれ独立してアルキル基を表し、Ｒ^２はそれぞれ独立してアルコキシ基、アルケニル基、水素原子、又は水酸基を表し、ｐ^１、ｑ^１、ａ^１、及びｂ^１は、［ｐ^１＋ｂ^１×ｑ^１］：［ａ^１×ｑ^１］＝１：０．２５〜９となる任意の正数を表す。） Specific examples of the polysilsesquioxane-based sealing material include a sealing material containing the resin A having an organopolysiloxane structure represented by the formula (1).

(In Formula (1), R ¹ each independently represents an alkyl group, R ² each independently represents an alkoxy group, an alkenyl group, a hydrogen atom, or a hydroxyl group, and p ¹ , q ¹ , a ¹ , and b ¹ represents an arbitrary positive number such that [p ¹ + b ¹ × q ¹ ]: [a ¹ × q ¹ ] = 1: 0.25 to 9)

（式（２）中、Ｒ^１及びＲ^２は、前記式（１）と同じ意味を表し、ｐ^２、ｑ^２、ｒ^２、ａ^２、及びｂ^２は、［ａ^２×ｑ^２］／［（ｐ^２＋ｂ^２×ｑ^２）＋ａ^２×ｑ^２＋（ｒ^２＋ｑ^２）］＝０〜０．３となる任意の０以上の数を表す。） Furthermore, the oligomer B which has the organopolysiloxane structure represented by Formula (2) may be included. When the oligomer B is included, the mixing ratio of the resin A and the oligomer B is preferably resin A: oligomer B = 100: 0.1 to 20 (mass ratio). By using the resin A as a main component, there is an effect of suppressing deterioration due to ultraviolet light or improving heat resistance.

(In Formula (2), R ¹ and R ² represent the same meaning as in Formula (1), and p ² , q ² , r ² , a ² , and b ² are [a ² × q ² ] / [Represents any number of 0 or more that satisfies ((p ² + b ² × q ² ) + a ² × q ² + (r ² + q ² )] = 0 to 0.3.)

The alkyl group represented by R ¹ may be linear or branched, and may have a cyclic structure, but may be a linear or branched alkyl group. Are preferable, and a linear alkyl group is more preferable. Moreover, although the carbon number of the said alkyl group is not specifically limited, A C1-C10 alkyl group is preferable, A C1-C6 alkyl group is more preferable, A C1-C3 alkyl group is More preferably, carbon number 1 is particularly preferable.

R ² independently represents an alkoxy group, an alkenyl group, a hydrogen atom, or a hydroxyl group, preferably an alkoxy group or a hydroxyl group.

When R ² is an alkoxy group, the alkoxy group may be linear or branched, and may have a cyclic structure, but may be linear or branched. Are more preferable, and a linear alkoxy group is more preferable. Moreover, although carbon number of the said alkoxy group is not specifically limited, A C1-C3 alkoxy group is preferable, C1-C2 is more preferable, and C1-C1 is especially preferable.

When R ² is an alkenyl group, the alkenyl group may be linear or branched, and may have a cyclic structure, but may be linear or branched. Are more preferable, and a linear alkenyl group is more preferable. Moreover, the carbon number of the alkenyl group is not particularly limited, but an alkenyl group having 2 to 4 carbon atoms is preferable. Specifically, the alkenyl group represented by R ¹ is preferably a vinyl group (ethenyl group), an allyl group (2-propenyl group), a 1-propenyl group, an isopropenyl group, or a butenyl group, and more preferably a vinyl group. preferable.

The plurality of R ¹ and R ² may be the same type of group or different from each other.

The resin A has at least one selected from the group consisting of a methyl group and an ethyl group as R ¹ , and R ² from the group consisting of a methoxy group, an ethoxy group, an isopropoxy group, and a hydroxyl group Those having one or more selected are preferable, R ¹ has one or more selected from the group consisting of a methyl group and an ethyl group, and R ² has a methoxy group, an ethoxy group, And those having one or more selected from the group consisting of isopropoxy groups and a hydroxyl group are more preferred.

  The weight average molecular weight (Mw) of the resin A is 1500 or more and 8000 or less. When the weight average molecular weight of the resin A is too small, the volume shrinkage rate at the time of curing increases, so that the stress generated in the sealing body increases and cracks are likely to occur. On the other hand, if it is too large, the viscosity of the encapsulated body before curing and the viscosity increase at the time of curing increase, and bubbles tend to be generated when alcohol or water generated by the condensation reaction volatilizes. The weight average molecular weight of the resin A is preferably 1500 or more and 7000 or less, and more preferably 2000 or more and 5000 or less.

  Resin A can be synthesized using an organosilicon compound having a functional group capable of generating a siloxane bond as a starting material, corresponding to each of the repeating units described above. Examples of the “functional group capable of generating a siloxane bond” include a halogen atom, a hydroxyl group, and an alkoxy group. As the organosilicon compound, for example, organotrihalosilane or organotrialkoxylane can be used as a starting material. Resin A can be synthesized by reacting such starting materials by a hydrolysis-condensation method at a ratio corresponding to the abundance ratio of each repeating unit. In addition, as the resin A synthesized in this manner, those commercially available as a silicone resin or an alkoxy oligomer can be used.

The oligomer B has at least one selected from the group consisting of a methyl group and an ethyl group as R ¹ , and R ² is selected from the group consisting of a methoxy group, an ethoxy group, an isopropoxy group, and a hydroxyl group It is preferable that R ¹ is a methyl group, and R ² has a methoxy group or a hydroxyl group.

  The weight average molecular weight of the oligomer B is less than 1500. If the weight average molecular weight of the oligomer B is too large, the crack resistance of the encapsulant after curing may be insufficient. The weight average molecular weight of the oligomer B is preferably 200 or more and less than 1500, and more preferably 250 to 1000.

  The oligomer B can be synthesized using an organosilicon compound having a functional group capable of generating a siloxane bond, corresponding to each of the above-described repeating units constituting the oligomer B. “Functional group capable of forming a siloxane bond” has the same meaning as described above. As the organosilicon compound, for example, organotrihalosilane or organotrialkoxylane can be used as a starting material. The silicone resin can be synthesized by reacting such starting materials by a hydrolysis condensation method at a ratio corresponding to the abundance ratio of each repeating unit.

  The difference in the weight average molecular weight from that of the resin A can be controlled, for example, by controlling the reaction temperature at the time of subjecting the starting material to a hydrolytic condensation reaction or the rate of addition of the starting material into the reaction system. As the silicone resin synthesized in this manner, those commercially available as a silicone resin or an alkoxy oligomer can be used.

  The weight average molecular weights of the resin A and the oligomer B can be measured using polystyrene as a standard using a commercially available GPC apparatus.

<Solvent a>
The solvent a used in the present invention is a solvent that has an ester bond and / or an ether bond, does not have a hydroxy group, and has a boiling point of 100 ° C. or higher and 200 ° C. or lower at 1 atm, and 130 ° C. As mentioned above, it is preferable that it is 200 degrees C or less. If the boiling point is 100 ° C. or higher, preferably 130 ° C. or higher, the solvent is less likely to volatilize during operations such as weighing, mixing, and potting, and the operability tends to be improved. The solvent does not easily remain afterward and tends to transmit light in the ultraviolet region (particularly the UV-C region). Further, by having a polar bond such as an ester bond or an ether bond, the solubility of the polysilsesquioxane-based sealing material can be increased, but transmission of light in the ultraviolet region (particularly in the UV-C region). From the viewpoint of, it is preferable not to have a functional group or aromatic ring structure containing other hetero elements

  Examples of the solvent a include ester solvents such as butyl acetate and butyl butyrate; ether solvents such as dioxane; glycol ether solvents such as ethylene glycol diethyl ether and diethylene glycol diethyl ether; glycols such as 2-ethoxyethyl acetate and 2-butoxyethyl acetate Ester solvents; and the like.

  The solvent a may be used in an amount that facilitates potting on the element placed on the substrate, and may be adjusted so that the viscosity of the obtained solution is from 10 mPas to 10,000 mPas. The amount used varies depending on the type of polysilsesquioxane-based encapsulant used, but is, for example, in the range of 40 to 90% by weight.

<Curing catalyst>
In the present invention, it is preferable to further use a curing catalyst. When using a curing catalyst, it is preferable to prepare a solution separate from the resin A and the oligomer B, and mix these solutions before use.

  Examples of the curing catalyst that can be used include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, and organic acids such as formic acid, acetic acid, succinic acid, citric acid, propionic acid, butyric acid, lactic acid, and succinic acid. Moreover, it is possible to use not only an acidic compound but also an alkaline compound. Specifically, ammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, or the like can be used.

  The amount of the curing catalyst used is in the range of 0.01% to 10% with respect to the polysilsesquioxane-based sealing material.

<Curing sealing material>
The use of the present invention is usually performed by potting an unsealed encapsulant composition containing the polysilsesquioxane-based encapsulant and the solvent a onto an element placed on a substrate, and then curing. Is called. That is, the sealing method of the element for UV-LED by use of the present invention is the first step of installing the element on the substrate, the polysilsesquioxane-based sealing material and the following solvent on the element installed on the substrate in the first step. a second step of potting a polysilsesquioxane-based encapsulant composition containing a, and a step of curing the polysilsesquioxane-based encapsulant potted in the second step.

  The element is placed on the substrate by a conventional method. Of course, you may install other structures normally required for a semiconductor light-emitting device, such as an electrode and wiring.

  The potting is usually performed by supplying a sealing material before curing onto a substrate with a dedicated dispenser. The amount of the sealing material to be supplied before curing varies depending on the structure, area, volume, and other electrode and wire wiring structures of the substrate and elements, but these elements and wire wirings are embedded and the light emitting element is covered. The thickness of the sealing material is preferably an amount that can be made as thin as possible, and more preferably an amount that makes the thickness 2 mm or less. When the sealing material on the element is thick, the sealing material gradually deteriorates due to heat and ultraviolet rays generated when the element emits light, and the transparency of the sealing material is lost due to discoloration. Luminance decreases over time. In particular, since the tendency is remarkable in a power LED for visible light having a light emission output current of 100 mA or more and a UV-LED that emits ultraviolet light having a wavelength of 350 nm or less, which has been developed in recent years, the thickness of the sealing material on the light emitting element is Thinning is effective.

  As curing conditions, a temperature and a time at which a normal polycondensation reaction occurs may be set. Specifically, the temperature is preferably 100 to 200 ° C., more preferably 130 to 200 ° C. in air at atmospheric pressure. The time is preferably about 1 to 5 hours. Further, in order to effectively promote the volatilization of the residual solvent in the encapsulant and the polycondensation reaction, the curing temperature may be increased stepwise to be cured.

The apparatus and measurement conditions used for the ultraviolet transmittance measurement described in the following examples are as follows.
<Ultraviolet visible transmittance measurement>
Device name: UV-3600 manufactured by Shimadzu Corporation
Attachment: Integrating sphere ISR-3100
Measurement wavelength: 220 to 800 nm
Background measurement: Atmosphere Measurement speed: Medium speed

As the resin A, a resin (A-1) having an organopolysiloxane structure represented by the formula (1) (Mw = 3500, in the formula (1), R ¹ = methyl group, R ² = methoxy group or hydroxyl group ) Was used. Table 1 shows the abundance ratio of each repeating unit of the resin A-1.

Example 1
In a flask placed in a water bath, 100 g of the resin (A-1) and 31.4 g of 2-ethoxyethyl acetate (boiling point 156 ° C.) are added, and the mixture is heated and stirred until the internal temperature reaches 85 ° C. A-1) was dissolved to obtain a polysilsesquioxane-based sealing material composition (α1).

  2 parts by mass of a curing catalyst containing 15% phosphoric acid is added to 100 parts by mass of the obtained polysilsesquioxane-based encapsulant composition (α1), and the mixture is sufficiently stirred and mixed to obtain a polysilsesquioxane-based composition. A sealing material composition (α1-1) was obtained. Thereafter, about 3.8 g of the obtained mixture was put into an aluminum cup, heated in an oven at a rate of 3.7 ° C./minute from room temperature to 150 ° C., and left at 150 ° C. for 5 hours. The hardened | cured material of the polysilsesquioxane type | system | group sealing material composition ((alpha) 1-1) was obtained. The thickness of the obtained cured product was 1.7 mm. The results of measuring the ultraviolet transmittance of the cured product are shown in FIG.

Example 2
In Example 1, polysilsesquioxane-based encapsulant composition (α1) was used in the same procedure as in Example 1 except that 2-butoxyethyl acetate (boiling point 192 ° C.) was used instead of 2-ethoxyethyl acetate. -2) and a cured product thereof.

Example 3
In Example 1, polysilsesquioxane-based sealing material composition (α1-3) was used in the same procedure as in Example 1 except that diethylene glycol dimethyl ether (boiling point 162 ° C.) was used instead of 2-ethoxyethyl acetate. And a cured product thereof.

Example 4
A polysilsesquioxane encapsulant composition (α1-4) was prepared in the same procedure as in Example 1 except that butyl acetate (boiling point: 126 ° C.) was used instead of 2-ethoxyethyl acetate in Example 1. And a cured product thereof.

  Table 2 shows the results of measuring the ultraviolet transmittance of the cured products obtained in Examples 1 to 4, respectively.

Claims (2)

Use of the following solvent a as a solvent for a polysilsesquioxane-based encapsulant for UV-LED containing the following resin A, in which the light transmittance at 260 nm of the cured product is 65% or more.
<Solvent a>
A solvent having an ester bond and / or an ether bond, having no hydroxy group, and having a boiling point under 1 atm of 100 ° C. or higher and 200 ° C. or lower
<Resin A>
Resin having organopolysiloxane structure represented by formula (1)

(In Formula (1), R ¹ each independently represents an alkyl group, R ² each independently represents an alkoxy group, an alkenyl group, a hydrogen atom, or a hydroxyl group, and p ¹ , q ¹ , a ¹ , and b ¹ represents an arbitrary positive number such that [p ¹ + b ¹ × q ¹ ]: [a ¹ × q ¹ ] = 1: 0.25 to 9) A cured product obtained by curing a polysilsesquioxane-based encapsulant composition for UV-LED containing the following polysilsesquioxane encapsulant containing resin A and the following solvent a, and transmitting light at 260 nm A cured product having a rate of 65% or more .
<Solvent a>
A solvent having an ester bond and / or an ether bond, having no hydroxy group, and having a boiling point under 1 atm of 100 ° C. or higher and 200 ° C. or lower
<Resin A>
Resin having organopolysiloxane structure represented by formula (1)

(In Formula (1), R ¹ each independently represents an alkyl group, R ² each independently represents an alkoxy group, an alkenyl group, a hydrogen atom, or a hydroxyl group, and p ¹ , q ¹ , a ¹ , and b ¹ represents an arbitrary positive number such that [p ¹ + b ¹ × q ¹ ]: [a ¹ × q ¹ ] = 1: 0.25 to 9)

Images