WO2023021891A1

WO2023021891A1 - Ultraviolet-curable composition

Info

Publication number: WO2023021891A1
Application number: PCT/JP2022/027585
Authority: WO
Inventors: 裕介富田
Original assignee: 三井化学株式会社
Priority date: 2021-08-19
Filing date: 2022-07-13
Publication date: 2023-02-23
Also published as: TW202309200A

Abstract

An ultraviolet-curable composition which contains a component (A) which is a polymerizable compound and a component (B) which is a filler, wherein: the average value of the parallel light transmittance at a wavelength of 380-780nm through a cured film (thickness of 100μm) of the ultraviolet-curable composition is at least 40%; the thermal conductivity obtained from formula (100) of a cured film (thickness of 100μm) of the ultraviolet-curable composition is 0.25W/m·K or higher; and the viscosity of the ultraviolet-curable composition measured at 25°C by using an E-type viscometer is 0.1-1,000 Pa·s, inclusive. (100): thermal conductivity=density×specific heat×thermal diffusivity

Description

UV curable composition

The present invention relates to an ultraviolet curable composition.

As the output of light-emitting elements such as light-emitting diodes (LEDs) and power devices is improving year by year, the heat dissipation design of devices is becoming more important. It is

As a technique related to a thermosetting heat dissipation material, there is one described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2017-78122).
Patent Document 1 describes a thermally conductive filler in which a refractive index control layer is provided on the surface of thermally conductive particles, and a resin composition containing the filler (claims 1 and 6). Since the object has both transparency and thermal conductivity, it is said that it leads to solving the heat problem of transparent members such as around LEDs and around displays (Paragraph 0006). In the same document, it is possible to use various thermoplastic resins, thermosetting resins such as epoxy resins, rubber resins such as silicone resins, and the like as resins in the resin composition (paragraph 0027). (Paragraphs 0037 to 0039).

Further, in Patent Document 2 (International Publication No. 2005/044875), a (meth)acrylic monomer or a partial polymer thereof adjusted so that the glass transition temperature of all polymer components after polymerization is 20° C. or less , a thermally conductive inorganic filler, a photopolymerization initiator, and a thermal polymerization initiator (claim 1). According to the document, by using a thermal polymerization initiator in combination with a photopolymerization initiator, a sufficiently high polymerization rate can be achieved by light irradiation and the heat generated at that time without actively heating the polymerizable composition. (page 3, lines 3-6).

JP 2017-78122 A WO2005/044875

However, according to the inventor's study, many heat dissipating materials are opaque materials, and in the case of members using opaque materials, there is room for improvement in that it is not possible to align the members or check the components after mounting. there were.
In addition, the components mounted together with the heat dissipation member may be vulnerable to heat, and there is room for improvement in the degree of freedom in designing the device.
Accordingly, the present invention provides a composition that has excellent photocuring properties and that can stably form a heat radiating member in a desired region.

According to the present invention, the following UV-curable composition, resin film, and heat-dissipating member are provided.
[1] The following components (A) and (B):
(A) a polymerizable compound,
(B) a UV curable composition comprising a filler,
The cured film (thickness 100 μm) of the ultraviolet curable composition has an average parallel light transmittance of 40% or more at a wavelength of 380 to 780 nm,
The cured film (thickness 100 μm) of the ultraviolet curable composition has a thermal conductivity of 0.25 W / m K or more, which is obtained by the following formula (100),
An ultraviolet curable composition having a viscosity of 0.1 Pa·s or more and 1000 Pa·s or less as measured at 25°C using an E-type viscometer.
Thermal conductivity = density x specific heat x thermal diffusivity (100)
[2] The UV-curable composition according to [1], wherein the content of the solvent in the UV-curable composition is 0.05% by mass or less relative to the entire UV-curable composition.
[3] The ultraviolet-curable composition according to [1] or [2], wherein the component (B) has a thermal conductivity of 3 W/m·K or more and 100 W/m·K or less.
[4] The ultraviolet curable composition according to any one of [1] to [3], wherein the component (B) has a refractive index of 1.40 or more and 1.80 or less at 25°C.
[5] The ultraviolet-curable composition according to any one of [1] to [4], wherein the component (A) has a refractive index at 25°C of 1.40 or more and 1.80 or less.
[6] Any one of [1] to [5], wherein the absolute value of the difference between the refractive index of component (A) at 25°C and the refractive index of component (B) at 25°C is 0.15 or less. The ultraviolet curable composition according to .
[7] The UV-curable composition according to any one of [1] to [6], further comprising component (C) below.
(C) Photopolymerization initiator [8] The ultraviolet curable composition according to [7], wherein the component (C) is a photocationic initiator.
[9] The UV-curable composition according to [7] or [8], wherein the component (A) is at least one selected from the group consisting of epoxy compounds and oxetane compounds.
[10] The ultraviolet-curable composition of [7], wherein the component (C) is a photoradical initiator.
[11] The UV-curable composition according to [7] or [10], wherein the component (A) is a (meth)acrylic compound.
[12] A resin film comprising a cured product of the ultraviolet-curable composition according to any one of [1] to [11].
[13] A heat dissipating member comprising a cured product of the ultraviolet curable composition according to any one of [1] to [11].

According to the present invention, it is possible to provide a composition that has excellent photocuring properties and that can stably form a heat-dissipating member in a desired region.

An embodiment of the present invention will be described below. In this embodiment, each component may be used alone or in combination of two or more. In addition, "~" representing a numerical range represents above and below, including both the upper limit and the lower limit.

(Ultraviolet curable composition)
In the present embodiment, the ultraviolet curable composition (hereinafter also simply referred to as the “composition” as appropriate) is specifically an ultraviolet curable thermally conductive composition, comprising the following components (A) and (B) including.
(A) Polymerizable compound (B) Filler The average value of parallel light transmittance at a wavelength of 380 to 780 nm of the cured film (thickness 100 μm) of the ultraviolet curable composition is 40% or more, and the ultraviolet curable composition is cured. For the film (thickness 100 μm), the thermal conductivity obtained by the following formula (100) is 0.25 W / m K or more, and an ultraviolet curable composition measured at 25 ° C. using an E-type viscometer The viscosity of the material is 0.1 Pa·s or more and 1000 Pa·s or less.
Thermal conductivity = density x specific heat x thermal diffusivity (100)

In the present embodiment, the composition contains components (A) and (B), and the parallel light transmittance, thermal conductivity and viscosity are each controlled within specific ranges, so that the composition has excellent photocuring properties. In addition, the heat dissipation member can be stably formed in a desired region.
By using the composition of the present embodiment, it is possible to obtain a resin film and a heat radiating member which are excellent in transparency and thermal conductivity and which are excellent in production stability.
Here, in order to obtain a composition whose parallel light transmittance, thermal conductivity and viscosity are each within the ranges described above, it is necessary to select components (A) and (B) contained in the composition and It is important to adjust the combination and blending amount.

The average value of parallel light transmittance at a wavelength of 380 to 780 nm of a cured film (thickness of 100 μm) of the composition is 40% or more, preferably 50% or more, from the viewpoint of improving the photocuring properties of the composition. Preferably it is 60% or more.
Further, the upper limit of the average value of the parallel light transmittance is specifically 100% or less, and may be, for example, 80% or less.
Here, the above-mentioned cured film is obtained under light irradiation conditions of UV-LED of wavelength 395 nm, illuminance of 1000 mW/cm ² and integrated light amount of 3000 mJ/cm ² , and has a thickness of 100 μm. The parallel light transmittance is the average transmittance of the cured film at 380 to 780 nm measured with an ultraviolet-visible spectrophotometer.

The thermal conductivity of the cured film (thickness 100 μm) of the composition is 0.25 W/m·K or more, preferably 0.30 W/m·K, from the viewpoint of improving the heat dissipation characteristics of the member obtained using the composition. m·K or more, more preferably 0.40 W/m·K or more, still more preferably 0.50 W/m·K or more, still more preferably 0.60 W/m·K or more.
In addition, from the viewpoint of suppressing the viscosity of the formulation from becoming excessively high, and from the viewpoint of making the handleability of the composition preferable, the thermal conductivity of the composition is preferably 5.0 W / m K or less. , more preferably 3.0 W/m·K or less, still more preferably 2.0 W/m·K or less.
Here, the cured film is obtained by photocuring with a UV-LED having a wavelength of 395 nm under the conditions of an illuminance of 1000 mW/cm ² and an integrated amount of light of 3000 mJ/cm ² , and has a thickness of 100 μm. The density, specific heat and thermal diffusivity of the resulting cured film are measured, and the thermal conductivity is determined by the following formula (100) based on the measured values.
Thermal conductivity = density x specific heat x thermal diffusivity (100)

The viscosity of the composition is 0.1 Pa·s or more, preferably 0.5 Pa·s or more, more preferably 1.0 Pa·s or more, from the viewpoint of suppressing sedimentation of the filler in the formulation.
From the viewpoint of workability of the formulation, the viscosity of the composition is 1000 Pa·s or less, preferably 500 Pa·s or less, more preferably 300 Pa·s or less, and still more preferably 150 Pa·s or less.
Here, the viscosity of the composition is measured with an E-type viscometer using a 3°×R9.7 cone at 25° C. at the following rotation speeds.
Viscosity less than 1 Pa s: 100 rpm
Viscosity 1 Pa s or more and less than 100 Pa s: 20 rpm
Viscosity of 100 Pa s or more: 5 rpm

Next, the constituent components of the composition will be explained with specific examples.

(Component (A))
Component (A) is a polymerizable compound. Specific examples of component (A) include compounds having cationic polymerizable functional groups such as epoxy groups, oxetanyl groups, and vinyl ether groups (hereinafter also referred to as "cationically polymerizable compounds"); and (meth)acryloyl groups , a compound having a radically polymerizable functional group such as a vinyl group (hereinafter also referred to as a “radically polymerizable compound”).

(Cationically polymerizable compound)
From the viewpoint of improving curability, the cationically polymerizable compound preferably contains at least one selected from the group consisting of epoxy compounds and oxetane compounds, more preferably epoxy compounds, and still more preferably epoxy compounds.

(epoxy compound)
Epoxy compounds are compounds having one or more epoxy groups in one molecule, and specific examples include monoepoxy compounds, difunctional epoxy compounds, and trifunctional or higher epoxy compounds.
From the viewpoint of improving curability, the epoxy compound includes a bifunctional or higher functional epoxy compound, more preferably a bifunctional epoxy compound.

From the viewpoint of improving curability, the epoxy compound preferably contains at least one selected from the group consisting of alicyclic epoxy compounds and aromatic epoxy compounds.

An alicyclic epoxy compound is specifically a compound having one or more alicyclic hydrocarbon structures and one or more epoxy groups in the molecule. The alicyclic epoxy compound may have one epoxy group or two or more epoxy groups in the molecule, but from the viewpoint of further enhancing the curability of the composition, it preferably contains two or more epoxy groups. have

Examples of alicyclic epoxy compounds include compounds containing a cycloalkene oxide structure such as an epoxycyclohexane structure, and compounds in which an epoxy group is bonded directly or via a hydrocarbon group to a cycloaliphatic hydrocarbon. From the viewpoint of enhancing the curability of the composition, the alicyclic epoxy compound is preferably a compound having a cycloalkene oxide structure.
Here, the cycloalkene oxide structure is a structure obtained by epoxidizing a cycloalkene with an oxidizing agent such as a peroxide, and is composed of two adjacent carbon atoms and an oxygen atom that constitute an aliphatic ring. It is an epoxy group. Cycloalkene oxide is, for example, cyclohexene oxide, cyclopentene oxide, preferably cyclohexene oxide.

The number of cycloalkene oxide structures in one molecule of the alicyclic epoxy compound having a cycloalkene oxide structure may be one, or two or more. From the viewpoint of enhancing the transparency, heat resistance, light resistance, etc. of the cured product, the number of cycloalkene oxide structures in one molecule is preferably two or more.

Examples of alicyclic epoxy compounds having a cycloalkene oxide structure include compounds represented by the following general formula (1).

In general formula (1), X is a single bond or a linking group. Linking groups are, for example, divalent hydrocarbon groups, carbonyl groups, ether groups (ether bonds), thioether groups (thioether bonds), ester groups (ester bonds), carbonate groups (carbonate bonds) and amide groups (amide bonds). and groups in which a plurality of these are linked.

Examples of divalent hydrocarbon groups include alkylene groups having 1 to 18 carbon atoms and divalent alicyclic hydrocarbon groups.
Among these, specific examples of the alkylene group having 1 to 18 carbon atoms include methylene group, methylmethylene group, dimethylmethylene group, ethylene group, propylene group and trimethylene group.
Further, specific examples of divalent alicyclic hydrocarbon groups include 1,2-cyclopentylene group, 1,3-cyclopentylene group, cyclopentylidene group, 1,2-cyclohexylene group, 1,3 divalent cycloalkylene groups (including cycloalkylidene groups) such as -cyclohexylene group, 1,4-cyclohexylene group and cyclohexylidene group.

From the viewpoint of improving curability, X is preferably a single bond or a linking group having an oxygen atom, more preferably a single bond.
From the same point of view, the linking group having an oxygen atom is preferably -CO- (carbonyl group), -O-CO-O- (carbonate group), -COO- (ester group), -O- (ether group ), -CONH- (amide group), a group in which a plurality of these groups are linked, or a group in which one or more of these groups are linked to one or more divalent hydrocarbon groups, more preferably -CO ₂ It is a CH ₂ - group.

Specific examples of the alicyclic epoxy compound represented by general formula (1) are shown below.

In the above formula, l represents an integer of 1-10, and m represents an integer of 1-30. R represents an alkylene group having 1 to 8 carbon atoms, preferably an alkylene group having 1 to 3 carbon atoms such as methylene, ethylene, propylene and isopropylene. n1 and n2 each independently represent an integer of 1 to 30;

Specific examples of alicyclic epoxy compounds having a cycloalkene oxide structure include 3′,4′-epoxycyclohexylmethyl, 3,4-epoxycyclohexane carboxylate (eg Celloxide (CEL) 2021P, manufactured by Daicel), and ε-caprolactone modification. 3′,4′-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate (Celoxide 2081, manufactured by Daicel Corporation) and (3,3′,4,4′-diepoxy)bicyclohexyl (Celoxide 8010, manufactured by Daicel Corporation) are mentioned.

Specific examples of aromatic epoxy compounds include glycidyl compounds having aromatic ring conjugated systems such as bisphenol skeletons, fluorene skeletons, biphenyl skeletons, naphthalene rings, and anthracene rings.
The aromatic epoxy compound is preferably a compound having a bisphenol skeleton, more preferably a bisphenol type epoxy resin such as bisphenol A type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin and bisphenol S type epoxy resin. and more preferably at least one of bisphenol F type epoxy resin (eg YL983U, manufactured by Mitsui Chemicals) and bisphenol E type epoxy resin (eg R1710, manufactured by Printec). Aromatic epoxy compounds having a bisphenol skeleton can be obtained, for example, by a condensation reaction between bisphenols such as bisphenol A, bisphenol E, bisphenol F, bisphenol S and fluorene bisphenol and epihalohydrin.

(oxetane compound)
The oxetane compound is a compound having one or more oxetanyl groups in one molecule, and specific examples thereof include monooxetane compounds, bifunctional oxetane compounds, and trifunctional or higher oxetane compounds. From the viewpoint of improving curability, the oxetane compound is preferably a bifunctional oxetane compound.

From the viewpoint of improving curability, the oxetane compound is preferably one or more bifunctional oxetane compounds selected from the group consisting of compounds represented by the following general formula (5) or (6).

In general formulas (5) and (6), R ⁵ is independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an allyl group, an aryl group, an aralkyl group, a furyl group or a thienyl group, preferably is an alkyl group having 1 to 6 carbon atoms. ^R6 is a divalent organic residue.

Among R ⁵ , the alkyl group having 1 to 6 carbon atoms specifically includes a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group and a cyclohexyl group.
Specific examples of aryl groups include phenyl, naphthyl, tolyl, and xylyl groups.
Specific examples of the aralkyl group include a benzyl group and a phenethyl group.

Specific examples of R ⁶ include an alkylene group, a polyoxyalkylene group, a phenylene group, a xylylene group, and structures represented by the following general formulas.

In the general formula above, R ³ is an oxygen atom, a sulfur atom, —CH ₂ —, —NH—, —SO—, —SO ₂ —, —C(CF ₃ ) ₂ — or —C(CH ₃ ) ₂ —. be.
R ⁴ is an alkylene or arylene group having 1 to 6 carbon atoms. Specific examples of the alkylene group having 1 to 6 carbon atoms include methylene group, ethylene group, propylene group, butylene group and cyclohexylene group.

Among R ⁶ , the polyoxyalkylene group preferably has 4 to 30 carbon atoms, more preferably 4 to 8 carbon atoms. Specific examples of polyoxyalkylene groups include polyoxyethylene groups and polyoxypropylene groups.

From the viewpoint of improving curability, the oxetane compound is preferably an oxetane compound represented by general formula (6), more preferably 3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}. Oxetane (for example, OXT-221 (manufactured by Toagosei Co., Ltd.)).

(Radical polymerizable compound)
Specific examples of radically polymerizable functional groups include one or more groups selected from the group consisting of (meth)acryloyl groups and vinyl groups. From the viewpoint of improving the curability of the composition, the radically polymerizable functional group preferably contains a compound containing a (meth)acryloyl group (also referred to herein as a "(meth)acrylic compound"), more preferably is a (meth)acrylic compound.
Here, in the present specification, a (meth)acryloyl group means at least one of an acryloyl group and a methacryloyl group. (Meth)acrylic means at least one of acrylic and methacrylic. (Meth)acrylate means at least one of acrylate and methacrylate.

((meth)acrylic compound)
The (meth)acrylic compound is a compound having one or more (meth)acryloyl groups in one molecule, and specifically includes a mono(meth)acrylic compound, a di(meth)acrylic compound, a (Meth)acrylic compounds are mentioned.
From the viewpoint of improving curability, the (meth)acrylic compound includes bifunctional (meth)acrylic compounds, more preferably di(meth)acrylic compounds.

Classification based on the hydrocarbon structure in (meth)acrylic compounds includes (meth)acrylic compounds having a chain structure; and (meth)acrylic compounds having a cyclic structure.
The chain structure may be a straight chain structure or a branched structure. The number of carbon atoms in the chain structure is, for example, 1 or more, preferably 2 or more, more preferably 4 or more, from the viewpoint of monomer availability. From the viewpoint of improving heat resistance, the number of carbon atoms in the shaped structure is preferably 20 or less, more preferably 14 or less.

Specific examples of (meth)acrylic compounds having a chain structure include trifunctional or higher (meth)acrylic compounds. The tri- or higher functional (meth)acrylic compound is preferably a trifunctional (meth)acrylic compound such as trimethylolpropane triacrylate (eg Light Acrylate TMP-A, manufactured by Kyoeisha Chemical Co., Ltd.).

Examples of the cyclic structure in the (meth)acrylic compound having a cyclic structure include an alicyclic hydrocarbon structure and an aromatic hydrocarbon structure. Moreover, the cyclic structure may be a monocyclic structure or a polycyclic structure such as a condensed cyclic hydrocarbon structure or a bridged cyclic hydrocarbon group structure.
From the viewpoint of improving the refractive index, the (meth)acrylic compound preferably has a cyclic hydrocarbon skeleton in its molecular structure.

Specific examples of the cyclic hydrocarbon skeleton include an alicyclic hydrocarbon skeleton and an aromatic hydrocarbon skeleton. The hydrocarbon skeleton is preferably an aromatic hydrocarbon skeleton, more preferably at least one selected from the group consisting of a bisphenol skeleton and a fluorene skeleton.

Specific examples of (meth)acrylic compounds having a bisphenol skeleton in the molecular structure include compounds having an alkylene oxide-modified bisphenol skeleton, preferably EO-modified bisphenol A diacrylate, EO-modified bisphenol A dimethacrylate, One or more compounds selected from the group consisting of PO-modified bisphenol A diacrylate, PO-modified bisphenol A methacrylate, propoxylated ethoxylated bisphenol A diacrylate and propoxylated ethoxylated bisphenol A dimethacrylate.

In addition, the compound having a bisphenol skeleton modified with alkylene oxide may be represented by the following general formula (7).

(In general formula (7) above, R ⁷ and R ⁸ are each independently a hydrogen atom or a methyl group. R ⁹ and R ¹⁰ are each independently a hydrogen atom, a methyl group or an aryl group. p and q are each independently a number of 1 or more and 20 or less.)

In general formula (7), R ⁷ and R ⁸ are preferably hydrogen atoms, and R ⁹ and R ¹⁰ are methyl groups, from the viewpoint of improving curability.
In addition, from the viewpoint of improving the binding property of the filler, p and q are each independently preferably a number of 1 or more and 10 or less, more preferably a number of 1 or more and 5 or less, and still more preferably 1 or more and 3 It is below.
From the same point of view, p+q is preferably 1 or more, more preferably 2 or more, preferably 20 or less, more preferably 10 or less, and still more preferably 6 or less.

Examples of commercially available products of the compound represented by the general formula (7) include NK ester A-BPE-2.2, ABE-300, A-BPE-4, A-BPE-10, A-BPE-20, A -BPP-3 (manufactured by Shin-Nakamura Chemical Co., Ltd.), light acrylate BP-4EAL and BP-4PA (manufactured by Kyoeisha Chemical Co., Ltd.).

Further, as the (meth)acrylic compound having a fluorene skeleton, specifically, a (meth)acrylate having a fluorene skeleton such as OGSOL EA-0200, EA-0300 (manufactured by Osaka Gas Chemical Co., Ltd.); OGSOL Epoxy (meth)acrylates having a fluorene skeleton such as GA-5060P and GA-2800 (manufactured by Osaka Gas Chemical Co., Ltd.) can be mentioned.
Further, as (meth)acrylic compounds having other aromatic skeletons, specifically, ethoxylated-o-phenylphenol acrylate (a compound represented by the following formula (8), such as A-LEN-10, Shin-Nakamura Kagaku Kogyo Co., Ltd.), compounds represented by the following formula (9) (eg POB-A, manufactured by Kyoeisha Chemical Co., Ltd.), benzyl acrylate (compounds represented by the following formula (10), such as Viscoat #160, Osaka Organic Chemical manufactured by Kogyosha).

From the viewpoint of improving the strength of the cured product, the content of component (A) in the composition is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 20% by mass or more, relative to the total composition of the composition. is 30% by mass or more, more preferably 40% by mass or more, still more preferably 50% by mass or more, and still more preferably 60% by mass or more.
Further, from the viewpoint of improving the heat dissipation properties of the composition, the content of component (A) in the composition is preferably 90% by mass or less, more preferably 80% by mass or less, based on the total composition of the composition. , more preferably 70% by mass or less.

The refractive index at 25° C. of component (A) is preferably 1.40 or higher, more preferably 1.45 or higher, and still more preferably 1.50 or higher, from the viewpoint of improving the transparency of the composition.
Further, from the viewpoint of improving the transparency of the composition, the refractive index at 25° C. of component (A) is preferably 1.80 or less, more preferably 1.75 or less, still more preferably 1.70 or less. It is more preferably 1.65 or less.
Here, the refractive index of component (A) is the refractive index nd for d-line (wavelength 587.6 nm) at room temperature (25 ° C.), specifically Abbe refractometer (manufactured by Atago, DR-M4) measured in
Moreover, when the component (A) contains a plurality of types of polymerizable compounds, the refractive index of the component (A) is determined as the sum of the refractive indices of the respective components multiplied by the mass fraction.

(Component (B))
Component (B) is a filler.
The filler material is specifically an inorganic compound. Specific examples of inorganic fillers include metal hydroxides such as aluminum hydroxide and magnesium hydroxide; and talc.

Moreover, the shape of the component (B) is, for example, particulate.
The average particle diameter _d50 of component (B) is preferably 0.5 μm or more, more preferably 1.0 μm or more, and still more preferably 2.5 μm or more, from the viewpoint of stably exhibiting thermal conductivity. be.
In addition, from the viewpoint of improving the flexibility of the adhesive layer thickness when the composition is used as an adhesive layer, the average particle size _d50 of the component (B) is preferably 100 μm or less, more preferably 50 μm or less. More preferably, it is 30 μm or less.
Here, the average particle size d ₅₀ of the component (B) is specifically obtained by measuring the particle size distribution of the particles of the component (B) on a volume basis by a laser diffraction method.

The thermal conductivity of component (B) is preferably 3 W/m·K or more, more preferably 5 W/m·K or more, still more preferably 10 W/m·K or more, from the viewpoint of improving the heat dissipation properties of the composition. is.
Further, from the viewpoint of improving the transparency of the composition, the thermal conductivity of component (B) is preferably 100 W/m·K or less, more preferably 75 W/m·K or less, and even more preferably 50 W/m·K or less. K or less, and more preferably 20 W/m·K or less.

The refractive index at 25° C. of component (B) is preferably 1.40 or higher, more preferably 1.45 or higher, still more preferably 1.50 or higher, from the viewpoint of improving the transparency of the composition.
Further, from the viewpoint of improving the transparency of the composition, the refractive index at 25° C. of component (B) is preferably 1.80 or less, more preferably 1.75 or less, and still more preferably 1.70 or less. .

The absolute value of the difference between the refractive index of component (A) at 25°C and the refractive index of component (B) at 25°C is preferably 0.15 or less from the viewpoint of improving the transparency of the cured product of the composition. , more preferably 0.10 or less, and still more preferably 0.05 or less.
The absolute value of the difference in refractive index between components (A) and (B) is preferably 0, and may be, for example, 0.01 or more.

(Component (C))
The composition may further comprise component (C): a photoinitiator. Specific examples of component (C) include at least one selected from the group consisting of photocationic initiators and photoradical initiators.

The photocationic initiator may be a compound capable of generating cationic species upon irradiation with light such as ultraviolet rays and initiating the polymerization of component (A). When component (C) is a cationic photoinitiator, component (A) is specifically a cationic polymerizable compound, preferably at least one selected from the group consisting of epoxy compounds and oxetane compounds.

Specific examples of photocationic initiators include salts of onium ions (onium salts) represented by the following general formula (11). Such onium salts release Lewis acids upon photoreaction.
[R ¹² _a R ¹³ _b R ¹⁴ _c R ¹⁵ _d W] ^v+ [MX _v+u ] ^u- (11)

In general formula (11), W represents S, Se, Te, P, As, Sb, Bi, O, I, Br, Cl, or N≡N. R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ each independently represent an organic group, and a, b, c and d each independently represent an integer of 0-3. Note that "a+b+c+d" is equal to the valence of W.

In general formula (11), M represents a metal or metalloid that constitutes the central atom of the halogenated complex [MX _v+u ]. Specific examples of M include B, P, As, Sb, Fe, Sn, Bi, Al, Ca, In, Ti, Zn, Sc, V, Cr, Mn, and Co. In general formula (11), X represents a halogen atom such as F, Cl, Br, u represents the net charge of the halide complex ion, and v represents the valence of M.

Specific examples of the onium ion in the general formula (11) include diphenyliodonium, bis(4-methoxyphenyl)iodonium, 4-methylphenyl-4′-isopropylphenyliodonium, bis(4-methylphenyl)iodonium, bis(4- tert-butylphenyl)iodonium, bis(dodecylphenyl)iodonium, tolylcumyliodonium, triphenylsulfonium, diphenyl-4-thiophenoxyphenylsulfonium, bis[4-(diphenylsulfonio)-phenyl]sulfide, bis[4 -(Di(4-(2-hydroxyethyl)phenyl)sulfonio)-phenyl]sulfide, η5-2,4-(cyclopentagenyl)[1,2,3,4,5,6-η-(methyl ethyl)benzene]-iron(1+).

Further, specific examples of anions in general formula (11) include tetrafluoroborate, tetrakis(pentafluorophenyl)borate, hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, and hexachloroantimonate.

The anion in general formula (11) is preferably selected from the group consisting of tetrafluoroborate, tetrakis(pentafluorophenyl)borate and hexafluorophosphate in terms of excellent safety for living organisms.

Commercially available examples of photocationic initiators represented by general formula (11) include Irgacure250, Irgacure270, Irgacure290 (manufactured by BASF), CPI-100P, CPI-101A, CPI-200K, CPI-210S, and CPI-310B. , CPI-400PG (manufactured by San-Apro), SP-150, SP-170, SP-171, SP-056, SP-066, SP-130, SP-140, SP-601, SP-606, SP-701 ( ADEKA), PI-2074 (trade name, Rhodia), and the like. Among them, from the viewpoint of improving curability, the photocationic initiator represented by the general formula (11) is preferably Irgacure270, Irgacure290, CPI-100P, CPI-101A, CPI-200K, CPI-210S, CPI-310B , CPI-400PG, SP-150, SP-170, SP-171, SP-056, SP-066, SP-601, SP-606, SP-701 and PI-2074, or Two or more.

The photoradical initiator may be a compound capable of generating radicals and initiating polymerization of the component (A) by being irradiated with light such as ultraviolet rays. When component (C) is a photoradical generator, component (A) is specifically a radically polymerizable compound, preferably a (meth)acrylic compound.
Specific examples of photoradical generators include one or two selected from the group consisting of acyloxine phosphide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, oxime ester compounds, alkylphenone compounds and benzophenone derivatives. The above are mentioned.

The content of component (C) in the composition is preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, relative to 100 parts by mass of component (A), from the viewpoint of improving curability. More preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more.
Further, from the viewpoint of suppressing coloring of the composition, the content of component (C) in the composition is preferably 10 parts by mass or less, more preferably 8 parts by mass relative to 100 parts by mass of component (A). Below, more preferably 7 parts by mass or less.

(solvent)
From the viewpoint of simplification of the process of using the composition, in the present embodiment, the composition preferably does not contain a solvent, or when the composition contains a solvent, the content of the solvent is 0% by mass. It is more than 0.05% by mass, more preferably 0.03% by mass or less. Specific embodiments in which the composition is solvent-free include those in which no solvent is intentionally included during preparation of the composition.

In this embodiment, the composition may further contain components other than the components described above. Specific examples of other components include photosensitizers, antioxidants, light resistance imparting agents, leveling agents, antifoaming agents, thixotropic agents, polymerization inhibitors, coupling agents and the like.

By including a photosensitizer in the composition, the curability of the composition can be further improved. Compositions include, for example, photocationic sensitizers.
The photosensitizer is preferably a compound that is excited by light with a wavelength of 350 nm to 450 nm from the viewpoint of being compatible with wavelength-selective light sources such as UV-LEDs. Specific examples of such sensitizers include polynuclear aromatics such as pyrene, perylene, triphenylene and anthracene; xanthenes such as fluorescein, eosin, erythrosine, rhodamine B and rose bengal; xanthones such as diethylthioxanthone; cyanines such as thiacarbocyanine and oxacarbocyanine; merocyanines such as merocyanine and carbomerocyanine; rhodacyanins; acridines such as flavin and acriflavin; acridones such as acridon and 10-butyl-2-chloroacridone; anthraquinones; squariums; styryls; is mentioned. Among these, the photosensitizer is preferably polycyclic aromatics, acridones, coumarins or base styryls, more preferably an anthracene compound, from the viewpoint of improving curability.

The content of the photosensitizer in the composition is preferably 0.1% by mass or more, more preferably 0.1% by mass or more, relative to 100 parts by mass of component (A), from the viewpoint of making the curability of the composition more preferable. is 0.2% by mass or more, more preferably 0.3% by mass or more, preferably 3% by mass or less, more preferably 2% by mass or less, and still more preferably 1% by mass or less.

In addition, when the composition contains a coupling agent, the adhesiveness between the cured product of the composition and the member adjacent to the cured product can be further enhanced.
Examples of coupling agents include silane coupling agents. Silane coupling is preferably a silane coupling agent having a functional group common to the polymerizable functional group in the component (A) from the viewpoint of improving the adhesion between the cured product of the composition and the member adjacent to the cured product. or a silane coupling agent having a functional group capable of reacting with the polymerizable functional group in component (A). For example, when component (A) contains an epoxy compound, the coupling agent is selected from the group consisting of a silane coupling agent having an epoxy group and a silane coupling agent having a functional group that reacts (for example, addition reaction) with the epoxy group. It is preferable to include one or more selected types.

Specific examples of silane coupling agents having epoxy groups include γ-glycidoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

Specific examples of silane coupling agents having functional groups capable of reacting with epoxy groups include amino groups such as primary amino groups and secondary amino groups; carboxyl groups, etc.; (meth)acryloyl groups; A ring agent is mentioned.

Specific examples of these silane coupling agents include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyltrimethoxysilane, N-2- (aminoethyl)-3-aminopropylmethyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane or 3-(4-methylpiperazino)propyltrimethoxysilane, trimethoxysilylbenzoic acid, γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ- Isocyanatopropyltriethoxysilane can be mentioned.

Coupling agents may also include those other than those described above, such as other silane coupling agents. Other silane coupling agents include, for example, vinyltriacetoxysilane and vinyltrimethoxysilane.
The molecular weight of the coupling agent is preferably 80 to 800 from the viewpoint of improving adhesion between the cured product of the composition and members adjacent to the cured product.

The content of the coupling agent in the composition is preferably 0.1 parts by mass with respect to 100 parts by mass of component (A) from the viewpoint of improving the adhesion between the cured product of the composition and the member adjacent to the cured product. parts or more, more preferably 0.5 parts by mass or more, preferably 5 parts by mass or less, more preferably 4 parts by mass or less, and even more preferably 3 parts by mass or less.

Next, a method for producing the composition will be described.
The method of making the composition is not limited and includes, for example, mixing components (A) and (B) and optionally other components. As a method for mixing each component, for example, various known kneaders such as a planetary stirrer, homodisper, universal mixer, Banbury mixer, kneader, two-roll, three-roll, and extruder are used alone or in combination, Examples include a method of uniformly kneading under conditions such as normal temperature, heating, normal pressure, reduced pressure, increased pressure, or inert gas flow.

Here, in order to more stably control the refractive index, thermal conductivity and viscosity of the composition within the ranges described above and obtain a composition that satisfies the conditions of the refractive index, thermal conductivity and viscosity described above, the composition should be: In the production of the product, it is important to select, combine, and control the amount of components (A) and (B) contained in the composition, for example.

In this embodiment, the obtained composition can also be used to form a resin film or a heat dissipation member. For example, the composition may be applied onto a substrate and dried. A known method such as an inkjet method, screen printing, or dispenser coating can be used for coating. Drying can be carried out by heating to a temperature at which component (A) does not polymerize, for example. There is no limitation on the shape of the heat radiating member to be obtained, and it can be, for example, a film shape.

The composition obtained in the present embodiment is excellent in transparency and thermal conductivity, and can stably form a heat-dissipating member in a desired region. Therefore, for example, transparency (visibility) and heat dissipation are required. It can be widely used in the field of electronic components. More specifically, the composition obtained in the present embodiment includes semiconductor devices such as power devices, light emitting devices, electronic devices such as batteries; automobiles and parts thereof; heat radiation members in lighting and parts, adhesives, coating agents, etc. It can be suitably used for
By using the composition of the present embodiment, for example, alignment of members and confirmation of components after mounting can be easily performed, and it is also possible to improve manufacturing stability of electronic devices and the like.
In addition, since the composition of the present embodiment can be suitably used in combination with members that are vulnerable to heat, the degree of freedom in device design can be improved.

The present invention will be described below with examples and comparative examples, but the present invention is not limited to these.

First, the materials used in the following examples are presented.
((A) polymerizable compound)
Polymerizable compound 1: an alicyclic epoxy compound represented by the following formula (12) (3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, bifunctional), CEL2021P, manufactured by Daicel Corporation, refractive index 1.0. 52
Polymerizable compound 2: bisphenol F type epoxy resin, YL983U, manufactured by Mitsubishi Chemical Corporation, refractive index 1.58
Polymerizable compound 3: Bisphenol E type epoxy resin, R1710, manufactured by Printec, refractive index 1.58
Polymerizable compound 4: bifunctional oxetane, OXT-221, manufactured by Toagosei Co., Ltd., refractive index 1.45
Polymerizable compound 5: EO-modified bisphenol A skeleton acrylic resin (ethoxylated bisphenol A diacrylate, bifunctional), A-BPE-4, manufactured by Shin-Nakamura Chemical Co., Ltd., refractive index 1.54
Polymerizable compound 6: monofunctional aromatic acrylic resin, POB-A, manufactured by Kyoeisha Chemical Co., Ltd., refractive index 1.57
Polymerizable compound 7: fluorene skeleton acrylic resin (bifunctional), Ogsol EA-0200, manufactured by Osaka Gas Chemical Co., Ltd., refractive index 1.63
Polymerizable compound 8: Polyfunctional acrylic resin (trimethylolpropane triacrylate, trifunctional), TMP-A, manufactured by Kyoeisha Chemical Co., Ltd., refractive index 1.47

((C) photoinitiator)
Initiator 1: photo cationic initiator, CPI-210S, manufactured by Sun-Apro, diphenyl-4-(phenylthio)phenylsulfonium hexafluorophosphate initiator 2: photo radical initiator, Omnirad TPO-H, manufactured by IGM Resins, 2, 4,6-trimethylbenzoyl-diphenylphosphine oxide (sensitizer)
Sensitizer 1: photosensitizer (anthracene compound), UVS-1331, manufactured by Kawasaki Kasei Co., Ltd. (additive)
Additive 1: Silane coupling agent (3-glycidoxypropyltrimethoxysilane), KBM-403, Shin-Etsu Chemical Co. Additive 2: Silane coupling agent (3-acryloxypropyltrimethoxysilane), KBM- 5103, manufactured by Shin-Etsu Chemical Co., Ltd.

((B) Filler)
Filler 1: Talc, SG-200, manufactured by Nippon Talc Co., Ltd., refractive index 1.54, thermal conductivity 5 W/m·K, average particle size d ₅₀ 2.7 μm
Filler 2 (aluminum hydroxide 1): aluminum hydroxide, CW-320LV, manufactured by Sumitomo Chemical Co., Ltd., refractive index 1.57, thermal conductivity 11 W/m K, average particle size d ₅₀ 18 μm
Filler 3 (aluminum hydroxide 2): aluminum hydroxide, CW-310LV, manufactured by Sumitomo Chemical Co., Ltd., refractive index 1.57, thermal conductivity 11 W/m K, average particle size d ₅₀ 10 μm
Filler 4: Alumina, ASFP20, manufactured by Denka, refractive index 1.76, thermal conductivity 25 W/m·K, average particle size d ₅₀ 0.3 μm
Filler 5: Silica, SO-C6, manufactured by Admatechs, refractive index 1.46, thermal conductivity 2 W/m·K, average particle size d ₅₀ 2.0 μm
Filler 6 (aluminum hydroxide 3): aluminum hydroxide, CL-303, manufactured by Sumitomo Chemical Co., Ltd., refractive index 1.57, thermal conductivity 11 W/m·K, average particle size d ₅₀ 4 μm

(Examples 1 to 11, Comparative Examples 1 to 4)
Each component was blended so as to have the blending composition shown in Table 1 to obtain a fluid composition containing no solvent. Specifically, each component was weighed into a 50 mL brown plastic bottle so that the composition would be 30 g, and stirred for 10 minutes with Awatori Rentaro (manufactured by Thinky Corporation). After that, the mixture was kneaded three times with three rolls to obtain a composition.
The physical properties of the composition obtained in each example or its cured product were measured by the following methods. The measurement results are also shown in Table 1. In Comparative Examples 3 and 4, the following measurements were not performed because the composition remained powdery without being pasted when the composition was prepared by the above-described method.

(parallel light transmittance)
Using 100 μm thick Teflon (registered trademark) as a spacer, the composition was sandwiched between non-alkali glasses of 25 mm×70 mm. Both surfaces were irradiated with a UV-LED with a wavelength of 395 nm under the conditions of an illuminance of 1000 mW/cm ² and an integrated light amount of 3000 mJ/cm ² to cure and obtain a sample for parallel light transmittance measurement.
The obtained sample was measured with a UV-visible spectrophotometer UV-2550 (manufactured by Shimadzu Corporation) to obtain an average transmittance of 380 to 780 nm.

(Thermal conductivity)
First, a cured product of the composition was obtained by the following procedure. That is, using a 100 μm thick Teflon (registered trademark) sheet as a formwork, the uncured composition was sandwiched between PET films, and the UV-LED with a wavelength of 395 nm was used under the conditions of an illuminance of 1000 mW/cm ² and an integrated light amount of 3000 mJ/cm ² . to obtain a cured product. The density, specific heat and thermal diffusivity of the obtained cured product were measured by the following methods.

(density measurement)
The obtained cured product was measured twice with an Accupic II 1340 automatic densitometer (manufactured by Shimadzu Corporation), and the average value was taken as the density.
(Specific heat measurement)
About 5 mg of the cured product obtained in a pan (B014-3018/B014-3003) manufactured by PerkinElmer was weighed and heated at a rate of 10°C/sec using a Diamond DSC (manufactured by PerkinElmer) to 23°C. The specific heat at
(Thermal diffusivity measurement)
The obtained cured product was measured three times with a periodic heating method diffusivity measuring device (FTC-RT, manufactured by Advance Riko Co., Ltd.), and the average value was taken as the thermal diffusivity.

(Calculation of thermal conductivity)
Using the measured values obtained above, the thermal conductivity of the cured product was obtained by the following formula (100).
Thermal conductivity = density x specific heat x thermal diffusivity (100)

(Viscosity of composition)
The viscosity of the resulting composition was measured with an E-type viscometer (TVE-35L, manufactured by Toki Sangyo Co., Ltd.) using a cone of 3°×R9.7 at 25° C. at the following rotational speeds.
Viscosity less than 1 Pa s: 100 rpm
Viscosity 1 Pa s or more and less than 100 Pa s: 20 rpm
Viscosity of 100 Pa s or more: 5 rpm

(hardening rate)
The composition was coated on a No. 25 mm×70 mm alkali-free glass. 6 bar coater, and cured by irradiating with a UV-LED with a wavelength of 395 nm under the conditions of an illuminance of 1000 mW/cm ² and an integrated amount of light of 3000 mJ/cm ² in the atmosphere.
Further, in the examples other than Examples 3 and 8 to 11, after curing under the above conditions, further curing was performed on a hot plate at 80° C. for 30 minutes to obtain a thermoset film.
The obtained cured sample and the sample before curing were subjected to IR measurement using FT/IR-6600 (manufactured by JASCO Corporation), and the curing rate was obtained according to the following formula.
Curing rate = [1-{reaction peak height (after curing)/reference peak height (after curing)}/reaction peak height (before curing)/reference peak height (before curing)}] × 100
The reference and reaction peaks for the reaction rate samples were as follows.
In the case of polymerizable compound 1, the reference peak is 1610 cm ^-1 and the reaction peak is 830 cm ^{-1 .}
In the case of polymerizable compounds 2 and 3, the reference peak is 1610 cm ^-1 and the reaction peak is 910 cm ^{-1 .}
In the case of polymerizable compound 4, the reference peak is 1610 cm ^-1 and the reaction peak is 980 cm ^-1
In the case of polymerizable compounds 5, 6, 7 and 8, the reference peak is 1722 cm ^-1 and the reaction peak is 810 cm ^-1 .
Curing rate at 50 μm GAP: A PET film is placed on a 2 cm × 5 cm × 700 μm thick non-alkali glass, a 50 μm thick Teflon (registered trademark) sheet is placed on the PET film as a GAP, and the gap between the Teflon (registered trademark) sheets is Place the composition on a PET film, place non-alkali glass on top of it, clip both ends, and apply UV-LED with a wavelength of 395 nm under the conditions of an illuminance of 1000 mW/cm ² and an integrated amount of light of 3000 mJ/cm ² . was irradiated and cured from non-adjacent alkali-free glass surfaces. The surface of the obtained cured sample which was not irradiated with UV was measured by IR, and the curing rate at 50 μm GAP was obtained in the same manner as the above curing rate.
Curing rate at 200 μm GAP: Curing rate at 200 μm GAP was obtained in the same manner as Curing rate at 50 μm GAP, except that the GAP was 200 μm thick.
Curing rate at 2 mm GAP: The curing rate at 2 mm GAP was obtained in the same manner as the curing rate at 50 µm GAP, except that the GAP was 2 mm thick.

(cross peel strength)
Cross-peel strength was measured as an index of the ability to stably form a cured film.
The composition is placed on a 25 mm × 70 mm non-alkali glass, a 50 µm thick Teflon (registered trademark) is placed as a spacer, and 25 mm × 70 mm non-alkali glass is stacked crosswise so that the area of the composition is 1.0. It was made to be ~5.0 mm ² . A UV-LED with a wavelength of 395 nm was used for curing under the conditions of an illuminance of 1000 mW/cm ² and an integrated light amount of 3000 mJ/cm ² . For examples other than Examples 3 and 8 to 11, after the above curing, they were further cured on a hot plate at 80° C. for 30 minutes to obtain thermoset samples.
The obtained sample was pulled with a 200X universal testing machine (manufactured by Intesco) at a speed of 5 mm/min to determine the strength. A case where the strength was 2.0 MPa or more was regarded as acceptable.

From Table 1, each example had an excellent balance between the excellent photocurability of the composition and the ability to stably form a cured film.

This application claims priority based on Japanese Patent Application No. 2021-134342 filed on August 19, 2021, and the entire disclosure thereof is incorporated herein.

Claims

The following components (A) and (B):
(A) a polymerizable compound,
(B) a UV curable composition comprising a filler,
The cured film (thickness 100 μm) of the ultraviolet curable composition has an average parallel light transmittance of 40% or more at a wavelength of 380 to 780 nm,
The cured film (thickness 100 μm) of the ultraviolet curable composition has a thermal conductivity of 0.25 W / m K or more, which is obtained by the following formula (100),
An ultraviolet curable composition having a viscosity of 0.1 Pa·s or more and 1000 Pa·s or less as measured at 25°C using an E-type viscometer.
Thermal conductivity = density x specific heat x thermal diffusivity (100)
The ultraviolet curable composition according to claim 1, wherein the content of the solvent in the ultraviolet curable composition is 0.05% by mass or less with respect to the entire ultraviolet curable composition.
The ultraviolet curable composition according to claim 1 or 2, wherein the component (B) has a thermal conductivity of 3 W/m·K or more and 100 W/m·K or less.
The ultraviolet curable composition according to any one of claims 1 to 3, wherein the component (B) has a refractive index at 25°C of 1.40 or more and 1.80 or less.
The ultraviolet curable composition according to any one of claims 1 to 4, wherein the component (A) has a refractive index of 1.40 or more and 1.80 or less at 25°C.
The ultraviolet curing according to any one of claims 1 to 5, wherein the absolute value of the difference between the refractive index of component (A) at 25°C and the refractive index of component (B) at 25°C is 0.15 or less. sex composition.
7. The ultraviolet curable composition according to any one of claims 1 to 6, further comprising component (C) below.
(C) photoinitiator
The ultraviolet curable composition according to claim 7, wherein the component (C) is a photocationic initiator.
The ultraviolet-curable composition according to claim 7 or 8, wherein the component (A) is at least one selected from the group consisting of epoxy compounds and oxetane compounds.
The ultraviolet curable composition according to claim 7, wherein the component (C) is a photoradical initiator.
The ultraviolet curable composition according to claim 7 or 10, wherein the component (A) is a (meth)acrylic compound.
A resin film comprising a cured product of the ultraviolet curable composition according to any one of claims 1 to 11.
A heat dissipating member comprising a cured product of the ultraviolet curable composition according to any one of claims 1 to 11.