JP2023096732A - Sealant, and sealant kit, and cured product - Google Patents

Abstract

To provide a sealant which barely shows a decreased transmittance of light with a wavelength of 270-280 nm or an increased durometer hardness in the use of a deep-ultraviolet light emitting device.SOLUTION: A sealant disclosed herein is a cured product of a composition comprising a polysiloxane compound bearing two or more trialkoxysilyl groups and a silane compound bearing two or more alkoxy groups bound to a silicon atom. In the sealant, a transmittance of ultraviolet rays with a wavelength of 270-280 nm is 90% or more for 1 mm of thickness.SELECTED DRAWING: None

Description

The present disclosure relates to encapsulants, encapsulant kits, and cured products.

In recent years, there has been an increasing demand for the use of deep ultraviolet rays (for example, light with a wavelength of 200 to 300 nm; hereinafter sometimes referred to as UVC) for sterilization and the like. For example, Patent Literature 1 discloses a deep-ultraviolet light-emitting device including a deep-ultraviolet light-emitting element chip and a sealing body made of a deep-ultraviolet sealing material that covers the emission surface of the deep-ultraviolet light-emitting chip.

Sealing materials for deep-ultraviolet light emitting devices are required to be composed of materials that have low UVC absorption and whose bonds are not cleaved by UVC. In addition, since soldering or the like is applied when manufacturing the light-emitting device, the encapsulant is required to be made of a material having excellent heat resistance. From this point of view, silicone resins mainly composed of Si—O bonds are used as encapsulants for deep-ultraviolet light emitting devices (for example, Patent Documents 2 and 3).

JP 2018-118412 A JP 2017-075203 A JP 2020-009858 A

However, even if a silicone resin encapsulant, which is considered to be suitable for encapsulating deep-ultraviolet light-emitting elements, is used, exposure to short-wavelength light and heat during operation of the light-emitting device can cause the wavelength to degrade. A decrease in transmittance for light of 270 to 280 nm, an increase in durometer hardness due to cure shrinkage, cracks, delamination, and the like may occur.

An object of the present disclosure is to provide a sealing material that suppresses a decrease in transmittance for light with a wavelength of 270 to 280 nm and an increase in durometer hardness associated with the use of a deep ultraviolet light emitting device. The present disclosure also aims to provide an encapsulant kit capable of preparing the encapsulant described above.

As a result of intensive studies by the present inventors regarding the above-mentioned problems, exposure of the encapsulant to short-wavelength light or heat causes unsaturated bonds to occur in some of the alkyl groups of the silicone resin. It has been found that saturated bonding is one of the causes of cracks and a decrease in light transmittance. Specifically, when the unsaturated bond occurs, curing shrinkage occurs due to cross-linking caused by the unsaturated bond, stress is generated in the sealing material, cracks occur, and delamination occurs at the interface with the LED element. I thought that problems like this would arise. In addition, when the unsaturated bond is generated, the unsaturated bond itself or its reaction product becomes a light absorption source, and it is thought that the light transmittance of the encapsulant (especially the transmittance for light with a wavelength of 270 to 280 nm) decreases. . The present disclosure is based on these findings.

One aspect of the present disclosure is a cured product of a composition containing a polysiloxane compound having two or more trialkoxysilyl groups and a silane compound having two or more alkoxy groups bonded to a silicon atom, and ultraviolet rays having a wavelength of 270 to 280 nm. Provided is a sealing material having a transmittance of 90% or more per 1 mm of thickness.

The sealing material is a cured product of a composition containing a polysiloxane compound, and has excellent transparency to ultraviolet rays having a wavelength of 270 to 280 nm. Therefore, the sealing material can be used particularly suitably as a sealing material for deep ultraviolet light emitting devices. In this embodiment, the reaction of the polysiloxane compound forms a three-dimensional network structure of siloxane chains. Since the composition of the sealing material contains a silane compound, when the composition is cured, the silane compound serves as a cross-linking point to bring the siloxane chains closer to each other, thereby increasing the density of the three-dimensional network structure and increasing the density of the siloxane chains. It is thought that the degree of freedom of Therefore, it is possible to suppress the reaction between side chain alkyl groups and suppress the generation of unsaturated bonds. In addition, even if unsaturated bonds and cross-linking resulting therefrom occur, the variation in hardness is small, hardening shrinkage hardly occurs, and the occurrence of cracks, peeling, and the like can be suppressed.

The silane compound is selected from the group consisting of alkyltrialkoxysilanes, dialkyldialkoxysilanes and oligomers thereof.

The oligomers may be dimers or trimers. When the oligomer is a dimer or trimer, the distance between siloxane chains in the cured product can be shortened, and the above effects can be exhibited more significantly.

The alkoxy group may have 1 to 3 carbon atoms. Since the number of carbon atoms in the alkoxy group is relatively small, the alcohol released by the curing reaction during preparation of the sealing material can be removed more easily.

The content of the silane compound may be 1 to 70 parts by mass with respect to 100 parts by mass of the polysiloxane compound.

One aspect of the present disclosure includes a polysiloxane compound having two or more trialkoxysilyl groups, an A agent containing a silane compound having two or more silicon-bonded alkoxy groups, and a B agent containing a curing agent. An encapsulant kit is provided for forming the encapsulant described above.

One aspect of the present disclosure is a cured product of a composition containing a polysiloxane compound having two or more trialkoxysilyl groups and a silane compound having two or more alkoxy groups bonded to a silicon atom, and ultraviolet rays having a wavelength of 270 to 280 nm. Provided is a cured product having a transmittance of 90% or more per 1 mm of thickness.

According to the present disclosure, it is possible to provide a sealing material that suppresses a decrease in transmittance for light with a wavelength of 270 to 280 nm and an increase in durometer hardness associated with the use of a deep ultraviolet light emitting device. The present disclosure can also provide encapsulant kits from which the encapsulants described above can be prepared.

Embodiments of the present disclosure will be described below. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents.

The materials exemplified in this specification can be used singly or in combination of two or more unless otherwise specified. The content of each component in the composition means the total amount of the multiple substances present in the composition unless otherwise specified when there are multiple substances corresponding to each component in the composition. .

One embodiment of the cured product is a cured product of a composition containing a polysiloxane compound having two or more trialkoxysilyl groups and a silane compound having two or more alkoxy groups bonded to silicon atoms, and having a wavelength of 270 to 280 nm. It has a transmittance of 90% or more per 1 mm of thickness with respect to ultraviolet rays. The cured product may be used, for example, as a sealing material or the like.

One embodiment of the encapsulant is a cured product of a composition containing a polysiloxane compound having two or more trialkoxysilyl groups and a silane compound having two or more alkoxy groups bonded to silicon atoms, and having a wavelength of 270 to 280 nm. of 90% or more per 1 mm of thickness for ultraviolet rays. The cured product contains a silicone resin that is a polymer of the polysiloxane compound. The shape of the encapsulant is not particularly limited, for example, it may be sheet-like or block-like, and in the deep ultraviolet light emitting device, the base material, the deep ultraviolet light emitting element and the spatial shape surrounded by the reflector and the like. It can be. The form of the sealing material is not particularly limited, and may be, for example, gel-like.

The polysiloxane compound may be, for example, polydialkylsiloxane modified with alkoxysilanes on both ends. The number of carbon atoms in the alkoxy group and alkyl group in the polydialkylsiloxane is preferably small, and may be, for example, 1-3 or 1-2. When the carbon number of the alkyl group is within the above range, it is possible to suppress the alkyl group in the polysiloxane compound from becoming a source of unsaturated bonds.

The above polysiloxane compound may be, for example, polydimethylsiloxane modified with alkoxysilanes at both ends, represented by the following general formula (A). In the following general formula (A), R represents an alkyl group. The number of carbon atoms in the alkyl group may be 1 or 2. Plural R's present in the general formula (A) may be the same or different from each other. In general formula (A) below, n may be, for example, 5 to 5,000 or 10 to 3,000.

A silane compound having two or more silicon-bonded alkoxy groups is a compound that reacts with a polysiloxane compound to act as a cross-linking agent for the polysiloxane chain and increase the density of the three-dimensional network structure of the polysiloxane chain. The silane compound may be selected from the group consisting of alkyltrialkoxysilanes, dialkyldialkoxysilanes, and oligomers thereof.

The silane compound may have two or three alkoxy groups. The number of carbon atoms in the alkyl group constituting the alkoxy group may be, for example, 1-3 or 1-2. When the number of carbon atoms in the alkyl group is within the above range, it becomes easier to remove the alcohol that is released during the curing reaction. The silane compound may have an alkyl group bonded to the silicon atom in addition to the alkoxy group. The number of carbon atoms in the alkyl group may be 1-3 or 1-2. When the number of carbon atoms in the alkyl group is within the above range, the alkyl group of the silane compound volatilizes after the curing reaction, is easily discharged out of the system, and becomes a source of unsaturated bonds. can be suppressed. Alkyl groups may specifically be methyl, ethyl, propyl, and isopropyl groups.

When the silane compound contains the oligomer, the oligomer may be an oligomer of at least one of an alkyltrialkoxysilane and a dialkyldialkoxysilane. The oligomers may be dimers or trimers, and may be dimers. When the oligomer is a dimer or trimer, the distance between polysiloxane chains constituting the silicone resin can be further shortened, and the variation in hardness of the encapsulant can be further reduced. , curing shrinkage can be further suppressed, and the occurrence of cracks, peeling, and the like can be suppressed more reliably.

Specifically, the above silane compounds include dimethoxydimethylsilane, diethyldimethoxysilane, dipropyldimethoxysilane, diisopropyldimethoxysilane, dimethoxy(methyl)isopropylsilane, dimethoxy(ethyl)propylsilane, diethoxy(methyl)propylsilane, diethoxy ( Ethyl)propylsilane, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, diethoxydimethylsilane, diethyldiethoxysilane, dipropyldiethoxysilane, dipropyldiethoxysilane, methyltriethoxysilane, ethyltriethoxysilane Silane, dimethyldipropoxysilane, methyltripropoxysilane, tripropoxypropylsilane, and oligomers thereof. The silane compound is preferably methyltrimethoxysilane or an oligomer thereof from the viewpoint of facilitating the removal of the alcohol derived from the alkoxy group from the encapsulant and reducing the source of unsaturated bonds.

The content of the silane compound in the composition may be adjusted based on the content of the polysiloxane compound. The lower limit of the content of the silane compound is, for example, 1 part by mass or more, 2 parts by mass or more, 3 parts by mass or more, 5 parts by mass or more, 10 parts by mass or more, 15 parts by mass or more with respect to 100 parts by mass of the polysiloxane compound. It may be 20 parts by mass or more, or 20 parts by mass or more. By setting the lower limit of the content of the silane compound within the above range, it is possible to further suppress changes in durometer hardness during use of the encapsulant. The upper limit of the content of the silane compound is, for example, 70 parts by mass or less, 60 parts by mass or less, 55 parts by mass or less, 50 parts by mass or less, 45 parts by mass or less, or It may be 40 parts by mass or less. By setting the upper limit of the content of the silane compound within the above range, a sealing material in which bleeding out of the silane compound is suppressed can be produced. The content of the silane compound may be adjusted within the above range, for example, 1 to 70 parts by mass, 1 to 60 parts by mass, or 1 to 40 parts by mass with respect to 100 parts by mass of the polysiloxane compound. you can

The composition may further contain other components in addition to the polysiloxane compound and the silane compound. Other components include, for example, curing agents, organic solvents, antioxidants, thixotropic agents, light stabilizers, flame retardants, thickeners, inorganic fillers, and the like.

The above sealing material has a transmittance of 90% or more per 1 mm of thickness for ultraviolet rays having a wavelength of 270 to 280 nm, and may be, for example, 91% or more, 92% or more, or 93% or more.

In the present specification, the transmittance is measured by an ultraviolet-visible spectrophotometer for light in the wavelength range of 270 to 280 nm, and the average value in the wavelength range is defined as the transmittance. As the ultraviolet-visible spectrophotometer, for example, "SolidSpec-3700 (product name)" manufactured by Shimadzu Corporation can be used. When the encapsulating material is to be measured, the transmittance and film thickness of the encapsulating material are measured, and then the absorption coefficient A is obtained using Beer-Lambert's law shown in formula (X). A value converted into a transmittance per 1 mm of thickness shall be used.
-log10 [transmittance] = A x [film thickness] ... formula (X)

The sealing material is suitable as a sealing material for a light-emitting element in a light-emitting device such as a deep-ultraviolet light-emitting device, and can exhibit practically sufficient hardness. The type A durometer hardness of the encapsulant can be, for example, 5 or greater, 10 or greater, 15 or greater, or 20 or greater. The upper limit of the type A durometer hardness of the encapsulant may be, for example, 60 or less, or 50 or less. The type A durometer hardness of the encapsulant may be adjusted within the ranges described above, eg, 5-60, or 10-50. By setting the type A durometer hardness within the above range, it is possible to further suppress the occurrence of cracks, peeling, and the like in the encapsulant due to stress that may occur during use.

In this specification, the type A durometer hardness is the rubber It means a value measured using a hardness tester type A, and specifically measured by the method described in the examples of the present specification. For the rubber hardness tester type A, for example, "Standard type DM-104A (product name)" manufactured by Muratec KDS Co., Ltd. can be used.

The composition that gives the cured product described above may be a mixture of a base material and a curing agent, and may be a so-called two-component composition. That is, the above composition may be prepared using a sealant kit having an A agent containing a base material and a B agent containing a curing agent. One embodiment of the encapsulant kit comprises a polysiloxane compound having two or more trialkoxysilyl groups and a silane compound having two or more silicon-bonded alkoxy groups. have The encapsulant kit is useful for forming the encapsulants described above.

The curing agent may be a catalyst that accelerates the curing reaction of the polysiloxane compound. As the curing agent, for example, an organic tin-based catalyst, an inorganic metal catalyst, or the like can be used. Organotin-based catalysts may be, for example, dibutyltin compounds, dioctyltin compounds, and the like. Dibutyltin compounds may specifically be dibutyltin laurate, dibutyltin carboxylate, dibutyltin oxide, and the like. The dioctyltin compound may specifically be dioctyltin dilaurate, dioctyltin carboxylate, and the like. Inorganic metal catalysts may specifically be inorganic tin compounds, inorganic bismuth compounds, and the like. The curing agent may contain dioctyltin dilaurate from the viewpoint of controlling the reaction speed and increasing the initial reflectance after curing.

The lower limit of the blending amount of the curing agent may be, for example, 0.05 parts by mass or more, 0.08 parts by mass or more, or 0.1 parts by mass or more with respect to 100 parts by mass of the polysiloxane compound. The upper limit of the content of the curing agent may be, for example, 1.5 parts by mass or less, 1.0 parts by mass or less, or 0.5 parts by mass or less with respect to 100 parts by mass of the polysiloxane compound.

Both the A agent and the B agent may contain an organic solvent. Organic solvents can be toluene, benzene, acetone, methyl ethyl ketone, diethyl ether, ethyl acetate, tetrahydrofuran, dimethylformamide, dichloromethane, dichloroethane, tetrachloroethane, and the like. Organic solvents may include toluene in terms of boiling point, volatility, and solubility.

Although several embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. Also, the descriptions of the above-described embodiments can be applied to each other.

Hereinafter, the present disclosure will be described in more detail using examples and comparative examples. It should be noted that the present disclosure is not limited to the following examples.

(Example 1)
In a container, 100 parts by mass of polydimethylsiloxane modified with methoxysilane at both ends (manufactured by Arakawa Chemical Industries, Ltd., Compoceran SL401 (product name)) as a polysiloxane compound, and 1 to 3-mers of methyltrimethoxysilane as a silane compound. A mixture (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-13 (product name)) was weighed to 20 parts by mass, and 20 parts by mass of toluene was added and mixed to prepare agent A.

Next, as a curing agent, 10 parts by mass of dioctyltin dilaurate (manufactured by Nitto Kasei Co., Ltd., Neostan U-810 (product name)) and 90 parts by mass of toluene were weighed and mixed in a container. Form B was prepared.

A composition was prepared by blending agents A and B so that the amount of polydimethylsiloxane in agent A and the amount of curing agent in agent B was 100:0.1 in mass ratio. The above composition was poured into a frame provided on a glass substrate to form a liquid film. Next, the liquid film was heat-treated at 80° C. for 1 hour, then heated to 120° C. and further heat-treated for 2 hours to perform a curing reaction to prepare a cured film. The resulting cured film ( The thickness of the cured product) was 1 mm.

<Evaluation of cured film>
For the cured film formed as described above, the transmittance (initial transmittance) for light with a wavelength of 270 to 280 nm and the type A durometer hardness (initial hardness) were measured according to the method described later. Next, after exposing the cured film to an environment of 150 ° C. for 65 hours, the transmittance (transmittance after test) and type A durometer hardness (hardness after test) are measured, and the relationship between initial transmittance and initial hardness The performance was evaluated based on Table 1 shows the results.

[Measurement of transmittance for light with a wavelength of 270 to 280 nm]
The transmittance is measured using an ultraviolet-visible spectrophotometer (Shimadzu Corporation, SolidSpec-3700 (product name)) to measure the transmittance for light in the wavelength range of 270 to 280 nm. The transmittance for light of 270 to 280 nm was taken as the transmittance.

[Measurement of type A durometer hardness]
The type A durometer hardness is measured according to the method described in JIS K 6253-3:2012 "Vulcanized rubber and thermoplastic rubber-Determination of hardness-Part 3: Durometer hardness", using a rubber hardness meter. Measurement was performed using Type A (Muratec KDS Co., Ltd., standard type DM-104A (product name)). The measurement was performed on a laminate having a total thickness of 6 mm by stacking 6 cured films.

(Examples 2-5)
In the same manner as in Example 1, except that the blending ratio of the mixture of polydimethylsiloxane modified with methoxysilane at both ends and the monomer to trimer of methyltrimethoxysilane in Agent A was changed as shown in Table 1. , to prepare a cured film. Each of the prepared cured films was evaluated in the same manner as in Example 1. Table 1 shows the results.

(Comparative example 1)
The procedure was the same as in Example 1, except that the mixture of methyltrimethoxysilane 1 to 3-mers was not blended as agent A, and only polydimethylsiloxane modified with methoxysilane at both ends was dissolved in toluene and used. to prepare a cured film. Each of the prepared cured films was evaluated in the same manner as in Example 1. Table 1 shows the results.

Claims (7)

A cured product of a composition containing a polysiloxane compound having two or more trialkoxysilyl groups and a silane compound having two or more alkoxy groups bonded to a silicon atom,
A sealing material having a transmittance of 90% or more per 1 mm of thickness for ultraviolet rays having a wavelength of 270 to 280 nm. The sealing material according to claim 1, wherein the silane compound is selected from the group consisting of alkyltrialkoxysilanes, dialkyldialkoxysilanes and oligomers thereof. 3. The encapsulant of claim 2, wherein said oligomer is a dimer or trimer. 4. The sealing material according to claim 2, wherein the alkoxy group has 1 to 3 carbon atoms. The sealing material according to any one of claims 1 to 4, wherein the content of the silane compound is 1 to 70 parts by mass with respect to 100 parts by mass of the polysiloxane compound. 6. Any one of claims 1 to 5, comprising a polysiloxane compound having two or more trialkoxysilyl groups, an A agent containing a silane compound having two or more silicon-bonded alkoxy groups, and a B agent containing a curing agent. An encapsulant kit for forming an encapsulant according to claim 1. A cured product of a composition containing a polysiloxane compound having two or more trialkoxysilyl groups and a silane compound having two or more alkoxy groups bonded to a silicon atom,
A cured product having a transmittance of 90% or more per 1 mm of thickness for ultraviolet rays having a wavelength of 270 to 280 nm.