JP2013071991A - Resin composition, b stage sheet, metal foil with applied resin, metal substrate and led substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition which can form a resin cured product having a high thermal conductivity and high electrical insulation properties.SOLUTION: The resin composition comprises a bifunctional epoxy resin having a biphenyl skeleton, a phenol resin, and an alumina group whose particle diameter D50 corresponding to cumulative 50% from the small particle size side of the weight cumulative particle size distribution thereof is 0.1-30 μm, including volumetric contents of 60 vol% or more, and the hardened material has a divergence rate of 5.0% or less of a true specific gravity/theoretical specific gravity.

Description

  The present invention relates to a resin composition, a B stage sheet, a metal foil with resin, a metal substrate, and an LED substrate.

  With the progress of higher density and downsizing of electronic devices, heat dissipation of electronic components such as semiconductors has become a major issue. Therefore, a resin composition having high thermal conductivity and high electrical insulation has been required, and has been put to practical use as a heat conductive sealing material or a heat conductive adhesive.

  In relation to the above, an epoxy resin composition containing an epoxy resin exhibiting liquid crystallinity and alumina powder is disclosed, and is said to have high thermal conductivity and excellent workability (see, for example, Patent Document 1).

JP 2008-13759 A

However, the epoxy resin composition described in Patent Document 1 sometimes fails to provide sufficient electrical insulation.
The present invention relates to a resin composition capable of forming a cured resin having high thermal conductivity and high electrical insulation, and a B stage sheet, a metal foil with resin, a metal substrate, and an LED substrate formed using the resin composition. The issue is to provide.

Specific means for solving the above problems are as follows.
<1> A bifunctional epoxy resin having a biphenyl skeleton, a phenol resin, and a particle diameter D50 corresponding to 50% cumulative from the small particle size side of the weight cumulative particle size distribution is 0.1 μm or more and 30 μm or less, and the content ratio A resin composition having a deviation rate from a theoretical specific gravity of 5.0% or less of the actual specific gravity of the cured product.

<2> The alumina particle group includes at least one of a first alumina particle group having a particle diameter D50 of 7 μm or more and 30 μm or less, and a second alumina particle group having a particle diameter D50 of less than 7 μm, The content ratio of the first alumina particle group to the total content of the second alumina particle group (first alumina particle group / second alumina particle group) is 1.0 or more and 12.0 or less on a mass basis The resin composition as described in <1>.

<3> A B-stage sheet comprising a semi-cured product of the resin composition according to <1> or <2>.

<4> Metal foil with resin provided with metal foil and the semi-hardened resin layer which is a semi-hardened body of the resin composition as described in <1> or <2> arrange | positioned on the said metal foil.

<5> A metal support, a cured resin layer that is a cured body of the resin composition according to <1> or <2> disposed on the metal support, and the cured resin layer. A metal substrate comprising a metal foil.

<6> A metal support, a cured resin layer that is a cured body of the resin composition according to <1> or <2> disposed on the metal support, and the cured resin layer. An LED substrate comprising a circuit layer made of a metal foil and an LED element disposed on the circuit layer.

  The present invention relates to a resin composition capable of forming a cured resin having high thermal conductivity and high electrical insulation, and a B stage sheet, a metal foil with resin, a metal substrate, and an LED substrate formed using the resin composition. The issue is to provide.

  In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended action of the process is achieved even when it cannot be clearly distinguished from other processes. . In the present specification, a numerical range indicated by using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. Further, in the present specification, the content of each component in the composition is the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition. Means.

<Resin composition>
In the resin composition of the present invention, a bifunctional epoxy resin having a biphenyl skeleton, a phenol resin, and a particle diameter D50 corresponding to 50% cumulative from the small particle size side of the weight cumulative particle size distribution is 0.1 μm or more and 30 μm or less. When the cured product includes an alumina particle group having a content rate of 60% by volume or more, a deviation rate from the theoretical specific gravity of the actual specific gravity of the cured product is within 5.0%.
Furthermore, in addition to the said essential component, the said resin composition is comprised including another component as needed.

  Since the alumina particle group contained in the resin composition at a specific content has a specific particle size distribution, the alumina is filled with high density. In addition to this, an epoxy resin having a specific skeleton is included, and the deviation rate of the actual specific gravity of the cured product from the theoretical specific gravity is within 5.0%, thereby achieving high thermal conductivity and high electrical insulation. . Furthermore, the resin composition exhibits excellent sheet flexibility when, for example, a B-stage sheet is configured.

The said resin composition can be made into hardened | cured material by heat-pressing. The measured specific gravity (actual specific gravity) of the cured product increases with the progress of the curing reaction of the resin composition under a predetermined effect condition, and converges to a certain value according to the configuration of the resin composition. .
The resin composition has a deviation rate from the theoretical specific gravity in the case of a cured product within 5.0%, but is preferably within 3.0% from the viewpoint of thermal conductivity. More preferably, it is within 5%.

Here, the hardened | cured material of the said resin composition in this invention shall be obtained on the following heat-pressing process conditions.
That is, as a condition for the heat treatment, the temperature is raised from 30 ° C. to 170 ° C. at a constant rate of 3 ° C. per minute, and is further maintained for 1 hour after reaching 170 ° C. and then rapidly cooled to room temperature. Shall. The heat treatment starts under a pressure of 2 MPa. After 100 minutes from the start of heating, the pressure is reduced at a constant rate to 0.7 MPa in 5 minutes. After reaching 0.7 MPa, the heat treatment ends. Until the pressure is maintained.

The specific gravity of the cured product can also be understood as the density. Thus, the actual specific gravity d ^r of the cured product of the resin composition, means the density of the cured product to be measured can be measured by Archimedes' method.
The theoretical specific gravity ^dt of the cured product is that the cured product of the resin composition is composed of an alumina particle group and a cured product of components other than the alumina particle group in the resin composition (hereinafter also referred to as “resin component”). When the volume content of the alumina particles is v ¹ vol% and the specific gravity is d ¹ , the volume content of the resin component is v ² vol% and the specific gravity is d ² , the following formula (1 ).
^{d t = d 1 × v 1} /100 + d 2 × v 2/100 (1)

As a specific example, the theoretical specific gravity of a cured resin containing 74% by volume of an alumina particle group having a specific gravity of 3.98 and having a specific gravity of a cured product derived from a resin component other than the alumina particle group of 1.20 is The equation gives 3.26.
3.98 × 0.74 + 1.20 × 0.26 = 3.26 (g / cm ³ )
In addition, the measured value is used for the specific gravity of the cured product derived from the resin composition other than the alumina particle group and the alumina particle group. Moreover, the hardened | cured material derived from the said resin component is obtained by hardening | curing the resin composition prepared similarly except not mix | blending an alumina particle group with a predetermined hardening method.

In addition, a decrease from the theoretical specific gravity is indicated as “deviation”, and the difference from the actual specific gravity of the cured product of the resin composition obtained by the Archimedes method based on the theoretical specific gravity is divided by the theoretical specific gravity. Is the divergence rate. That is, the deviation rate is expressed by the following equation (2).
Deviation rate = {(theoretical specific gravity−actual specific gravity) ÷ theoretical specific gravity} (%) (2)

  As a method of setting the deviation rate within a predetermined range, for example, a method of appropriately mixing a plurality of types of alumina particle groups having different particle diameters D50 as described later, or an additive such as a dispersant or a coupling agent is appropriately selected. And a method to be used.

[alumina]
The resin composition is a group of alumina particles having a particle diameter D50 (hereinafter also simply referred to as “particle diameter D50”) corresponding to 50% cumulative from the small particle size side of the weight cumulative particle size distribution of 0.1 μm to 30 μm. Is contained in the entire volume of the resin composition in an amount of 60% by volume or more.
The content of the alumina particles is preferably 70% by volume or more in the total solid content of the resin composition from the viewpoint of thermal conductivity, electrical insulation, and flexibility of the B stage sheet, and is 72 volumes. % Or more is more preferable.
In addition, solid content in a resin composition means the residue which removed the volatile component from the component which comprises a resin composition.

The particle diameter D50 of the alumina particle group is measured using a laser diffraction method, and corresponds to the particle diameter at which the weight accumulation is 50% when the weight accumulation particle size distribution curve is drawn from the small particle diameter side.
The particle size distribution measurement using the laser diffraction method can be performed using a laser diffraction scattering particle size distribution measuring device (for example, LS230 manufactured by Beckman Coulter, Inc.).

Preferably, the alumina particle group includes at least one of a first alumina particle group having a particle diameter D50 of 7 μm or more and 30 μm or less and a second alumina particle group having a particle diameter D50 of less than 7 μm, The content ratio of the first alumina particle group to the total content of the second alumina particle group (first alumina particle group / second alumina particle group) is 1.0 or more and 12.0 or less on a mass basis. It is more preferable.
When the alumina particle group contains at least two kinds of alumina particle groups having different particle diameters D50 in a specific content ratio, the thermal conductivity of the resin cured product is further improved.

  When the alumina particle group includes two or more second alumina particle groups having different particle diameters D50, the content of the first alumina particle group with respect to the total content of the two or more second alumina particle groups The ratio is preferably 1.0 or more and 12.0 or less.

The content ratio of the first alumina particle group to the second alumina particle group (first alumina particle group / second alumina particle group) is preferably 1.0 or more and 12.0 or less on a mass basis. Is more preferably 1.0 or more and 8.0 or less, and further preferably 1.0 or more and 5.0 or less.
When the content ratio is in such a range, the thermal conductivity of the cured resin is further improved. Further, the deviation rate from the actual specific gravity can be further reduced.

  When the alumina particle group contained in the resin composition includes two or more types of alumina particle groups having different particle sizes D50, the particle size distribution corresponds to the particle size D50 of the two or more types of alumina particle groups, respectively. It will have more than one peak. Moreover, the peak area of each peak becomes a thing according to the content rate of each alumina particle group.

  The first alumina particle group preferably has a particle size D50 corresponding to 50% cumulative from the small particle size side of the weight cumulative particle size distribution of 7 μm to 30 μm, more preferably 7 μm to 25 μm. Preferably, it is more preferably 10 μm or more and 22 μm or less from the viewpoint of thermal conductivity and electrical insulation, and further preferably 15 μm or more and 20 μm or less from the viewpoint of maintaining the flatness of the sheet.

  The second alumina particle group preferably has a particle diameter D50 corresponding to 50% cumulative from the small particle size side of the weight cumulative particle size distribution is less than 7 μm, but from the viewpoint of thermal conductivity and electrical insulation. The thickness is preferably 0.1 μm or more and less than 7 μm, and more preferably 0.2 μm or more and less than 7 μm from the viewpoint of reducing voids in the sheet.

The ratio of the particle diameter D50 of the first alumina particle group to the particle diameter D50 of the second alumina particle group is not particularly limited. From the viewpoint of thermal conductivity and flexibility of the B stage sheet, the ratio of the particle diameter D50 of the first alumina particle group to the particle diameter D50 of the second alumina particle group is 1.0 or more and 10.0 or less. Is more preferable and 2.0 or more and 8.0 or less are more preferable.
In addition, when said 2nd alumina particle group consists of 2 or more types of alumina particle groups from which particle diameter D50 differs, the particle diameter D50 of a 2nd alumina particle group is particle | grains as the whole 2nd alumina particle group. Means diameter D50

  In the alumina particle group, from the viewpoint of thermal conductivity and electrical insulation, the ratio of the particle diameter D50 of the first alumina particle group to the particle diameter D50 of the second alumina particle group is 1.0 or more and 10.0 or less. The ratio of the content of the first alumina particle group to the total content of the second alumina particle group is preferably 1.0 or more and 8.0 or less, with respect to the particle diameter D50 of the second alumina particle group. The ratio of the particle diameter D50 of the first alumina particle group is 2.0 or more and 8.0 or less, and the ratio of the content of the first alumina particle group to the total content of the second alumina particle group is 1.0. More preferably, it is 5.0 or less.

  If the alumina particle group in the present invention has the particle size distribution described above, there is no particular limitation on the crystal structure and the like, such as α-alumina, β-alumina, γ-alumina, δ-alumina, θ-alumina and the like. It may consist of either. Among these, at least one of the first alumina particle group and the second alumina particle group is preferably α-alumina, more preferably composed only of α-alumina, and from α-alumina single crystal particles. More preferred is alumina.

  The first alumina particle group and the second alumina particle group can be appropriately selected from commercially available ones. Also, the alumina powder that becomes transition alumina by heat treatment or heat treatment is fired in an atmosphere gas containing hydrogen chloride (see, for example, JP-A-6-191833, JP-A-6-191836, etc.) It may be manufactured by.

In addition to the alumina particle group, the resin composition of the present invention may contain inorganic fibers whose main component is alumina and whose number average fiber diameter is 1 μm to 50 μm. In the present invention, the “inorganic fiber mainly composed of alumina” means an inorganic fiber containing 50% by mass or more of alumina. Especially, it is preferable that it is an inorganic fiber containing 70 mass% or more of alumina, and it is more preferable that it is an inorganic fiber containing 90 mass% or more of alumina. The number average fiber diameter of such inorganic fibers is 1 μm to 50 μm, preferably 1 μm to 30 μm, more preferably 1 μm to 20 μm. Moreover, the fiber length of this inorganic fiber is 0.1 mm-100 mm normally.
As such inorganic fibers, commercially available fibers are usually used. Specifically, Artex (manufactured by Sumitomo Chemical Co., Ltd.), Denka Arsen (manufactured by Denki Kagaku Kogyo Co., Ltd.), Maftec Bulk Fiber (Mitsubishi Chemical) Sangyo Co., Ltd.).

  The content in the case of using such inorganic fibers is usually 5% by mass to 70% by mass, preferably 5% by mass to 50% by mass with respect to the mass of the alumina particle group, and the total mass of alumina and inorganic fibers. However, an amount of 30% by mass to 95% by mass is usually used in the solid content of the resin composition.

  The resin composition of the present invention may further contain an inorganic filler other than alumina, if necessary, in addition to the alumina. Examples of the inorganic filler include non-conductive materials such as magnesium oxide, aluminum nitride, boron nitride, silicon nitride, silicon oxide, aluminum hydroxide, and barium sulfate. Examples of the conductive material include gold, silver, nickel, and copper. These inorganic fillers can be used in one kind or a mixed system of two or more kinds.

[Epoxy resin]
The resin composition of the present invention contains at least one bifunctional epoxy resin having a biphenyl skeleton. The epoxy resin is not particularly limited as long as it is a compound having at least one biphenyl skeleton and having two epoxy groups.
Specific examples include biphenyl type epoxy resins and biphenylene type epoxy resins.

  As the biphenyl type epoxy resin, it is preferable to use an epoxy resin represented by the following general formula (III).

In general formula (III), R ^{1 to} R ⁸ each independently represents a hydrogen atom or a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms, and n represents an integer of 0 to 3.
Examples of the substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, an isopropyl group, and an isobutyl group.
Among these, R ^{1 to} R ⁸ are preferably a hydrogen atom or a methyl group.

  Examples of the biphenyl type epoxy resin represented by the general formula (III) include 4,4′-bis (2,3-epoxypropoxy) biphenyl or 4,4′-bis (2,3-epoxypropoxy) -3,3. Reaction of epoxy resin based on ', 5,5'-tetramethylbiphenyl, epichlorohydrin and 4,4'-biphenol or 4,4'-(3,3 ', 5,5'-tetramethyl) biphenol And an epoxy resin obtained by the treatment. Among these, an epoxy resin mainly composed of 4,4'-bis (2,3-epoxypropoxy) -3,3 ', 5,5'-tetramethylbiphenyl is preferable. As such a compound, YX-4000 (manufactured by Japan Epoxy Resin Co., Ltd.), YL-6121H (manufactured by Japan Epoxy Resin Co., Ltd.), YSLV-80XY (manufactured by Toto Kasei Co., Ltd.) and the like are commercially available.

  Examples of the biphenylene type epoxy resin include an epoxy resin represented by the following general formula (IV).

In general formula (IV), R ^{1 to} R ⁹ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, or carbon. The aralkyl group of several 6-10 is represented, n shows the integer of 0-10.

Examples of the alkyl group having 1 to 10 carbon atoms include methyl group, ethyl group, propyl group, butyl group, isopropyl group, and isobutyl group. Examples of the alkoxy group having 1 to 10 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Examples of the aryl group having 6 to 10 carbon atoms include a phenyl group, a tolyl group, and a xylyl group. Examples of the aralkyl group having 7 to 10 carbon atoms include a benzyl group and a phenethyl group.
Among these, R ^{1 to} R ⁹ are preferably a hydrogen atom or a methyl group.

  As the biphenyl type epoxy resin represented by the general formula (IV), for example, NC-3000 (trade name, manufactured by Nippon Kayaku Co., Ltd.) is commercially available.

  The bifunctional epoxy resin having a biphenyl skeleton in the present invention is a compound represented by the general formula (III) or the general formula (IV) from the viewpoint of thermal conductivity, electrical insulation and flexibility of the B stage sheet. It is preferable to include at least one of the above, and it is more preferable to include at least one of the compounds represented by the general formula (III).

  Although there is no restriction | limiting in particular as content rate of the bifunctional epoxy resin which has the said biphenyl skeleton in the total solid of the resin composition of this invention, From a thermal conductivity, electrical insulation, and a flexible viewpoint of a B stage sheet | seat. It is preferably 3% by mass or more and 10% by mass or less, and more preferably 4% by mass or more and 7% by mass or less.

  The resin composition of the present invention may contain other epoxy resins in addition to the bifunctional epoxy resin having a biphenyl skeleton. As other epoxy resins, conventionally known epoxy resins can be used without particular limitation as long as they do not have a biphenyl skeleton.

  Specifically, phenols such as phenol novolac type epoxy resin, orthocresol novolak type epoxy resin, epoxy resin having triphenylmethane skeleton, phenol, cresol, xylenol, resorcin, catechol, bisphenol A, bisphenol F, etc. And / or obtained by condensation or cocondensation of naphthols such as α-naphthol, β-naphthol, dihydroxynaphthalene and the like and a compound having an aldehyde group such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, salicylaldehyde in the presence of an acidic catalyst. Epoxidized novolac resin.

  Bisphenol A, bisphenol F, bisphenol S, stilbene type epoxy resin, hydroquinone type epoxy resin, glycidyl ester type epoxy resin obtained by reaction of polybasic acid such as phthalic acid and dimer acid and epichlorohydrin, diaminodiphenylmethane, isocyanuric acid and other polyamines Glycidylamine-type epoxy resin obtained by the reaction of chlorohydrin and epichlorohydrin, epoxidized product of co-condensation resin of dicyclopentadiene and phenol, epoxy resin having naphthalene ring, phenol-aralkyl resin, phenol-aralkyl resin containing biphenylene skeleton, naphthol -Epoxidized aralkyl type phenol resin such as aralkyl resin, trimethylolpropane type epoxy resin, terpene modified epoxy resin, olefin Examples include linear aliphatic epoxy resins, alicyclic epoxy resins, and sulfur atom-containing epoxy resins obtained by oxidizing a combination with a peracid such as peracetic acid. These may be used alone or in combination of two or more. You may use together.

  It is preferable that the resin composition of this invention contains at least 1 sort (s) chosen from the epoxy resin which has a naphthalene ring from a flexible viewpoint at the time of comprising a B stage sheet.

  The epoxy resin having a naphthalene ring is not particularly limited as long as it is a compound having at least one naphthalene ring and at least one epoxy group. For example, HP4032D (made by DIC Corporation) can be mentioned.

  When the resin composition of the present invention contains another epoxy resin (preferably an epoxy resin having a naphthalene ring), the content is not particularly limited. For example, the bifunctional epoxy resin having the biphenyl skeleton On the other hand, it can be 0.01 mass% or more and 15 mass% or less, and it is preferable that it is 0.01 mass% or more and 12 mass% or less. With such a content, the thermal conductivity, electrical insulation, and flexibility of the B stage sheet are more effectively improved.

  When the resin composition of the present invention contains another epoxy resin (preferably an epoxy resin having a naphthalene ring), the content ratio of the bifunctional epoxy resin having a biphenyl skeleton and the other epoxy resin (2 having a biphenyl skeleton) There are no particular restrictions on the functional epoxy resin / other epoxy resins). For example, from the viewpoint of flexibility, it can be set to 80/20 or more, preferably 90/10 or more, and more preferably 95/5 or more.

[Phenolic resin]
The resin composition includes at least one phenol resin. The phenol resin can be appropriately selected from those usually used as a curing agent for epoxy resins. Among them, from the viewpoint of thermal conductivity and electrical insulation, it contains a phenol resin (hereinafter sometimes referred to as “novolak resin”) containing at least one compound having a structural unit represented by the following general formula (I). Is preferred. The phenol resin acts as a curing agent for an epoxy resin, for example.
By including a phenol resin having a specific structure, the thermal conductivity can be more effectively improved, and the pot life in the state before curing can be sufficiently increased.

In the general formula (I), R ¹ represents an alkyl group, an aryl group, or an aralkyl group, and R ² and R ³ each independently represent a hydrogen atom, an alkyl group, an aryl group, a phenyl group, or an aralkyl group, m represents an integer of 0-2.

In the general formula (I), R ¹ represents an alkyl group, an aryl group, or an aralkyl group. The alkyl group, aryl group and aralkyl group represented by R ¹ may further have a substituent if possible. Examples of the substituent include an alkyl group, an aryl group, a halogen atom, and a hydroxyl group. Can be mentioned.
m represents an integer of 0 to 2, and when m is 2, two R ¹ may be the same or different. In the present invention, m is preferably 0 or 1, and more preferably 0.

  The phenol resin preferably contains at least one compound having the structural unit represented by the general formula (I), but two or more compounds having the structural unit represented by the general formula (I). May be included.

The phenol resin preferably includes a partial structure derived from resorcinol as a phenolic compound, but may further include at least one partial structure derived from a phenolic compound other than resorcinol. Examples of phenolic compounds other than resorcinol include phenol, cresol, catechol, and hydroquinone. The said phenol resin may contain the partial structure derived from these individually by 1 type or in combination of 2 or more types.
Here, the partial structure derived from the phenolic compound means a monovalent or divalent group constituted by removing one or two hydrogen atoms from the benzene ring portion of the phenolic compound. The position where the hydrogen atom is removed is not particularly limited.

  The partial structure derived from the phenolic compound other than the resorcinol includes phenol, cresol, catechol, hydroquinone, 1,2,3-trihydroxybenzene, 1,2 from the viewpoint of thermal conductivity, adhesiveness, and storage stability. It is preferably a partial structure derived from at least one selected from 1,4-trihydroxybenzene and 1,3,5-trihydroxybenzene, and is a partial structure derived from at least one selected from catechol and hydroquinone It is more preferable.

  The content ratio of the partial structure derived from resorcinol in the phenol resin is not particularly limited, but from the viewpoint of thermal conductivity and storage stability, the content ratio of the partial structure derived from resorcinol in the total mass of the phenol resin. Is preferably 55% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more.

In the general formula (I), R ² and R ³ each independently represent a hydrogen atom, an alkyl group, an aryl group, a phenyl group, or an aralkyl group. The alkyl group, phenyl group, aryl group and aralkyl group represented by R ² and R ³ may further have a substituent if possible, and examples of the substituent include an alkyl group, an aryl group, a halogen atom, An atom, a hydroxyl group, etc. can be mentioned.

R ² and R ³ in the present invention are preferably a hydrogen atom, an alkyl group, a phenyl group or an aryl group from the viewpoint of storage stability and thermal conductivity, and are preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms. Alternatively, an aryl group having 3 to 6 carbon atoms and a phenyl group are more preferable, and a hydrogen atom is further preferable.
Furthermore, from the viewpoint of heat resistance, it is also preferable that at least one of R ² and R ³ is an aryl group.

  Specifically, the phenol resin in the present invention is preferably a phenol resin containing a compound having a partial structure represented by any one of the following general formulas (Ia) to (If).

In the general formula (Ia) to the general formula (If), i and j represent the content ratio (% by mass) of the structural unit derived from each phenolic compound, i is 5% by mass to 30% by mass, and j is 70%. The total of i and j is 100% by mass.
The phenol resin in the present invention includes a structural unit represented by any one of the general formula (Ia) and the general formula (Ie) from the viewpoint of thermal conductivity and storage stability, and i is 5% by mass to 20% by mass. Wherein j is preferably 80% by mass to 95% by mass, includes a structural unit represented by the general formula (Ia), i is 2% by mass to 10% by mass, and j is 90% by mass. It is more preferable that it is% -98 mass%.

  The phenol resin preferably contains a compound having a structural unit represented by the above general formula (I), but more preferably contains at least one compound represented by the following general formula (II).

In the general formula (II), R ¹¹ represents a hydrogen atom or a monovalent group derived from a phenolic compound represented by the following general formula (IIp), and R ¹² represents a monovalent group derived from a phenolic compound. Represent. ^{Further, R 1, R 2, R 3} , m and n are respectively the same as ^{R 1, R 2, R 3} , m and n in the general formula (I).
The monovalent group derived from the phenolic compound represented by R ¹¹ and R ¹² is a monovalent group constituted by removing one hydrogen atom from the benzene ring portion of the phenolic compound, and the hydrogen atom is removed. There is no particular limitation on the position.

In general formula (IIp), p represents an integer of 1 to 3. ^Further, R 1, ^{R 2} and ^{R 3} are respectively the same meaning as ^R 1, ^{R 2} and ^{R 3} in formula (I), m represents an integer of 0 to 2.

The phenolic compound in R ¹¹ and R ¹² is not particularly limited as long as it is a compound having a phenolic hydroxyl group. Specific examples include phenol, cresol, catechol, resorcinol, hydroquinone and the like. Among these, from the viewpoints of thermal conductivity and storage stability, at least one selected from cresol, catechol, and resorcinol is preferable.

  The number average molecular weight of the phenol resin is preferably 800 or less, more preferably 300 or more and 700 or less, and more preferably 350 or more and 550 or less from the viewpoint of thermal conductivity.

  When the said resin composition contains the phenol resin containing the compound which has a structural unit represented by the said general formula (I), the monomer which is a phenolic compound which comprises a phenol resin may further be included. Although there is no restriction | limiting in particular as content rate (henceforth "monomer content rate") of the monomer which is a phenolic compound which comprises a phenol resin, It is preferable that it is 5 mass%-80 mass%, and 15 mass It is more preferable that it is% -60 mass%, and it is further more preferable that it is 20 mass%-50 mass%.

  When the monomer content ratio is 5% by mass or more, an increase in the viscosity of the phenol resin is suppressed, and the adhesion of the inorganic filler is further improved. Moreover, by being 80 mass% or less, a higher-order higher-order structure is formed by the crosslinking reaction in the case of hardening, and the outstanding heat conductivity and heat resistance can be achieved.

  In addition, as a monomer of the phenolic compound which comprises a phenol resin, resorcinol, catechol, and hydroquinone can be mentioned, It is preferable that a resorcinol is included as a monomer at least.

  Further, the content ratio of the phenol resin in the total solid content of the resin composition is not particularly limited, but from the viewpoint of thermal conductivity, electrical insulation, flexibility of the B stage sheet, and pot life, 1 mass. % To 10% by mass, more preferably 2% to 5% by mass.

The content ratio of the bifunctional epoxy resin having the biphenyl skeleton and the phenol resin in the resin composition (epoxy resin / phenol resin) is, for example, 0.6 to 1.5 on an equivalent ratio basis. In view of thermal conductivity, flexibility of the B-stage sheet, and pot life, it is preferably 0.8 or more and 1.25 or less, and more preferably 0.8 or more and 1.2 or less.
In addition, the content ratio on an equivalent basis is specifically calculated from the following formula.
Formula Content ratio (epoxy resin / phenolic resin) = Σ (epoxy resin amount / epoxy resin epoxy equivalent) / Σ (phenol resin amount / phenolic resin phenol equivalent)

  In addition to the phenol resin, the resin composition may contain other curing agent other than the phenol resin, if necessary. As other curing agents, conventionally known curing agents can be used without particular limitation. Specifically, for example, polyaddition type curing agents such as amine curing agents and mercaptan curing agents, latent curing agents such as imidazole, and the like can be used.

The resin composition may contain other components as necessary in addition to the essential components. Examples of other components include a solvent, a silane coupling agent, a dispersant, and an anti-settling agent.
The solvent is not particularly limited as long as it does not inhibit the curing reaction of the resin composition, and a commonly used organic solvent can be appropriately selected and used.
Specific examples of the organic solvent include ketone solvents such as 2-butanone and cyclohexaneone, and alcohol solvents such as cyclohexanol.

(Silane coupling agent)
It is preferable that the resin composition further includes at least one silane coupling agent. By including a silane coupling agent, it plays a role of forming a covalent bond between the surface of the alumina particles and the organic resin surrounding the surface (corresponding to a binder agent), thereby efficiently transferring heat, and Contributes to the improvement of insulation reliability by preventing moisture from entering. Furthermore, the rate of deviation from the actual specific gravity of the cured product can be further reduced.

  As the silane coupling agent, commercially available ones can be usually used, but considering the compatibility with the epoxy resin and the phenol resin and the reduction of the heat conduction loss at the interface between the resin layer and the alumina, an epoxy group at the end is used. It is preferable to use a silane coupling agent having an amino group, a mercapto group, a ureido group or a hydroxyl group.

Specifically, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3 , 4-epoxycyclohexyl) ethyltrimethoxysilane and other silane coupling agents having an epoxy group; 3-aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, 3- (2-aminoethyl) ) Silane coupling agents having an amino group such as aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, etc. of A silane coupling agent having a sulfanyl group (mercapto group); a silane coupling agent having a ureido group such as 3-ureidopropyltriethoxysilane; and a silane coupling agent typified by SC-6000KS2 Examples include oligomers (manufactured by Hitachi Chemical Coated Sand Co., Ltd.).
These silane coupling agents can be used alone or in combination of two or more.

  Among these silane coupling agents, a silane coupling agent having an epoxy group and a silane coupling agent having an alkyl group are selected from the viewpoint of thermal conductivity and the rate of deviation from the theoretical specific gravity of the actual specific gravity of the cured product. It is preferable to include at least one, and more preferably to include at least one selected from silane coupling agents having an epoxy group.

When the resin composition contains a silane coupling agent, the content of the silane coupling agent in the resin composition is a group of alumina particles from the viewpoint of the rate of deviation from the theoretical specific gravity of the thermal conductivity and the actual specific gravity of the cured product. The total content is preferably 0.01% by mass or more and 5.00% by mass or less, and more preferably 0.10% by mass or more and 3.00% by mass or less.
Further, when the resin composition contains a silane coupling agent, from the viewpoint of the deviation rate from the theoretical specific gravity of the thermal conductivity and the actual specific gravity of the cured product, the silane coupling agent having an epoxy group and the silane cup having an alkyl group It is preferable that at least one selected from ring agents is contained in an amount of 0.01% by mass or more and 5.00% by mass or less based on the total content of the alumina particle group, and at least one selected from silane coupling agents having an epoxy group More preferably, the seed is contained in an amount of 0.10% by mass to 3.00% by mass with respect to the total content of the alumina particle group.

(Dispersant)
It is preferable that the resin composition further includes at least one dispersant. By including the dispersant, the thermal conductivity is further improved, and further, the deviation rate from the theoretical specific gravity of the cured product can be further reduced. Aggregation of alumina can be suppressed by using a dispersant. Thereby, generation | occurrence | production of the space | gap (void) physically confined in an alumina aggregate can be suppressed, As a result, the actual specific gravity as a resin hardened | cured material which contains 60 volume% or more of alumina particles improves. That is, the actual specific gravity of the cured product can be brought close to the theoretical specific gravity.

As the dispersant, any dispersant that is effective for improving the dispersibility of alumina particles can be appropriately selected from commonly used dispersants without particular limitation.
Specific examples of the dispersant include amine esters of polyetherester acids, amide amine salts of polycarboxylic acids, amine salts of polyester acids, alkylamine salts of higher fatty acids, and amine salts of phosphate esters. Some of these are classified as surfactants. When viewed as a surfactant, any of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, and the like may be used.

  Anionic surfactants include oleic acid / N-methyltaurine salt, oleic acid / potassium / diethanolamine salt, alkyl ether sulfate / triethanolamine salt, polyoxyethylene alkyl ether sulfate / triethanolamine salt, special modified polyether ester Amine salt of acid, amine salt of higher fatty acid derivative, amine salt of special modified polyester acid, amine salt of high molecular weight polyether ester acid, amine salt of special modified phosphoric acid ester, high molecular weight polyester acid amide amine salt, amide amine of special fatty acid derivative Salts, alkylamine salts of higher fatty acids, amidoamine salts of high molecular weight polycarboxylic acids, sodium laurate, sodium stearate, sodium oleate, sodium lauryl sulfate, cetyl sulfate ester Tellurium salt, stearyl sulfate ester sodium salt, oleyl sulfate ester sodium salt, lauryl ether sulfate ester salt, sodium alkylbenzene sulfonate, oil-soluble alkylbenzene sulfonate, α-olefin sulfonate, higher alcohol phosphate monoester disodium salt Higher alcohol phosphoric acid diester disodium salt, zinc dialkyldithiophosphate and the like.

  As cationic surfactants, benzyldimethyl {2- [2- (P-1,1,3,3-tetramethylbutylphenoxy) ethoxy] ethyl} ammonium chloride, octadecylamine acetate, tetradecylamine acetate , Octadecyltrimethylammonium chloride, tallow trimethylammonium chloride, dodecyltrimethylammonium chloride, coconut trimethylammonium chloride, hexadecyltrimethylammonium chloride, behenyltrimethylammonium chloride, coconut dimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium chloride, octadecyldimethylbenzylammonium chloride Dioleoyldimethylammonium chloride, 1-hydroxy ester L-2-tallow imidazoline quaternary salt, 2-heptadecenyl-hydroxyethyl imidazoline, stearamide ethyl diethylamine acetate, stearamide ethyl diethylamine hydrochloride, triethanolamine monostearate formate, alkyl pyridium salt, higher alkyl amine ethylene Examples thereof include oxide adducts, polyacrylamide amine salts, modified polyacrylamide amine salts, and perfluoroalkyl quaternary ammonium iodides.

  Examples of amphoteric surfactants include dimethyl coconut betaine, dimethyl lauryl betaine, sodium laurylaminoethylglycine, sodium laurylaminopropionate, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, amide betaine, imidazolinium betaine, lecithin, 3- [ ω-fluoroalkanoyl-N-ethylamino] -1-propanesulfonic acid sodium, N- [3- (perfluorooctanesulfonamido) propyl] -N, N-dimethyl-N-carboxymethyleneammonium betaine, and the like can be given.

  Nonionic surfactants include coconut fatty acid diethanolamide (1: 2 type), coconut fatty acid diethanolamide (1: 1 type), bovine fatty acid diethanolamide (1: 2 type), and bovine fatty acid diethanolamide (1: 1). Type), oleic acid diethanolamide (1: 1 type), hydroxyethyl lauryl amine, polyethylene glycol lauryl amine, polyethylene glycol coconut amine, polyethylene glycol stearyl amine, polyethylene glycol beef tallow amine, polyethylene glycol beef tallow propylene diamine, polyethylene glycol dioleyl amine, Dimethyl lauryl amine oxide, dimethyl stearyl amine oxide, dihydroxyethyl lauryl amine oxide, perfluoroalkylamine oxide, polyvinyl chloride Lidon, higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, glycerin fatty acid ester, pentaerythritol fatty acid ester, sorbit fatty acid ester, sorbitan fatty acid ester, Examples include sugar fatty acid esters.

Specific examples of the dispersing agent include Ajinomoto Finetech Co., Ltd. Addisper Series, Enomoto Kasei Co., Ltd. HIPLAAD Series, Kao Corporation Homogenol Series, and the like. These dispersants can be used alone or in combination of two or more.
Among these, at least one selected from the HIPLAAD series manufactured by Enomoto Kasei Co., Ltd. is preferable from the viewpoint that the actual specific gravity of the cured product is close to the theoretical value.

When the resin composition includes a dispersant, the content of the dispersant in the resin composition is the total content of the alumina particles from the viewpoint of the deviation rate from the theoretical specific gravity of the thermal conductivity and the actual specific gravity of the cured product. It is preferably 0.03% by mass or more and 1.0% by mass or less, more preferably 0.03% by mass or more and 0.5% by mass or less, and 0.03% by mass or more and 0.3% by mass or less. A range is further preferred.
Further, when the resin composition contains a dispersant, from the viewpoint of the deviation rate from the theoretical specific gravity of the conductivity and the actual specific gravity of the cured product, at least one selected from fatty acid and salts of derivatives thereof is added to the total of the alumina particles. The content is preferably 0.03% by mass or more and 1.0% by mass or less, more preferably 0.03% by mass or more and 0.5% by mass or less, and more preferably 0.03% by mass or more and 0.3% by mass. It is more preferable that the content is not more than%.

<B stage sheet>
The B stage sheet of the present invention is made of a semi-cured product of the resin composition and has a sheet shape.
The B stage sheet can be manufactured by a manufacturing method including, for example, a step of applying and drying the resin composition on a release film to form a resin film, and a step of heat-treating the resin film to a B stage state. .
By forming by heat-treating the resin composition, the resin composition is excellent in thermal conductivity and electrical insulation, and is excellent in flexibility and usable time as a B stage sheet.
The B-stage sheet of the present invention is the viscosity of the resin sheet, measured at dynamic viscoelasticity (frequency 1 Hz, load 40 g, temperature rising rate 3 ° C./min) at room temperature (25 ° C.) 10 ⁴ to 10 ⁵ mPa · In contrast to s, the viscosity decreases to 10 ² to 10 ³ mPa · s at 100 ° C. Moreover, the cured resin layer after curing described later is not melted even by heating.

Specifically, for example, a varnish-like resin composition (hereinafter also referred to as “resin varnish”) in which a solvent such as methyl ethyl ketone or cyclohexane is added on a release film such as a PET film is dried after being applied. Thus, a resin film in which a resin layer is provided on the release film can be obtained.
Application | coating can be implemented by a well-known method. Specific examples of the coating method include comma coating, die coating, lip coating, and gravure coating. As a coating method for forming a resin layer with a predetermined thickness, a comma coating method in which an object to be coated is passed between gaps, a die coating method in which a resin varnish whose flow rate is adjusted from a nozzle, or the like can be applied. . For example, when the thickness of the resin layer before drying is 50 μm to 500 μm, it is preferable to use a comma coating method.

Since the resin layer after coating has hardly progressed the curing reaction, it has flexibility, but it has poor flexibility as a sheet, and in the state where the PET film as a support is removed, the sheet is not self-supporting, It is difficult to handle. Therefore, in the present invention, the resin composition is B-staged by heat treatment described later.
Conditions for heat-treating the obtained resin film are not particularly limited as long as the resin composition can be semi-cured to the B stage state, and can be appropriately selected according to the configuration of the resin composition. Specifically, for example, the heating temperature can be set to 80 ° C. to 130 ° C. for 1 second to 30 seconds.
The heat treatment method is preferably selected from a hot vacuum press, a hot roll laminate, and the like. As a result, voids in the resin layer generated during coating can be reduced, and a flat B-stage sheet can be efficiently produced.

  The thickness of the B stage sheet can be appropriately selected according to the purpose. For example, it can be 50 μm or more and 200 μm or less, and preferably 60 μm or more and 150 μm or less from the viewpoint of thermal conductivity, electrical insulation, and sheet flexibility. It can also be produced by hot pressing while laminating two or more resin films.

<Metal foil with resin>
The metal foil with resin of this invention is equipped with metal foil and the semi-hardened resin layer which is a semi-hardened body of the said resin composition arrange | positioned on the said metal foil. By having the semi-cured resin layer derived from the resin composition, the thermal conductivity, electrical insulation, and flexibility are excellent.
The semi-cured resin layer is obtained by heat-treating the resin composition so as to be in a B-stage state.

The metal foil is not particularly limited, such as a gold foil, a copper foil, and an aluminum foil, but generally a copper foil is used.
The thickness of the metal foil is not particularly limited as long as it is 1 μm to 35 μm, but the flexibility is further improved by using a metal foil of 20 μm or less.
Moreover, as metal foil, nickel, nickel-phosphorus, nickel-tin alloy, nickel-iron alloy, lead, lead-tin alloy, etc. are used as intermediate layers, and 0.5 μm to 15 μm copper layer and 10 μm to 300 μm on both sides. A composite foil having a three-layer structure provided with a copper layer or a two-layer structure composite foil in which aluminum and copper foil are combined can also be used.

  The metal foil with a resin can be produced by forming a resin layer by applying and drying the resin composition on the metal foil, and the method for forming the resin layer is as described above.

The production conditions of the resin-coated metal foil are not particularly limited, but it is preferable that 80% by mass or more of the organic solvent used for the resin varnish is volatilized in the resin layer after drying. The drying temperature is about 80 ° C. to 180 ° C., and the drying time can be determined in consideration of the gelling time of the varnish, and is not particularly limited. The application amount of the resin varnish is preferably applied so that the thickness of the resin layer after drying is 30 μm to 100 μm, and more preferably 30 μm to 80 μm.
The resin layer after drying becomes a B stage state by heat treatment. The heat treatment conditions for the resin composition are the same as the heat treatment conditions for the B-stage sheet.

<Metal substrate>
The metal substrate of the present invention includes a metal support, a cured resin layer that is a cured body of the resin composition disposed on the metal support, and a metal foil disposed on the cured resin layer. The cured resin layer disposed between the metal support and the metal foil is formed by heat-treating the resin composition so as to be in a cured state, so that adhesiveness, thermal conductivity, electricity Excellent insulation.

  The material and thickness of the metal support are appropriately selected according to the purpose. Specifically, for example, a metal such as aluminum or iron can be used, and the thickness can be set to 0.5 mm or more and 5 mm or less.

  Moreover, the metal foil arrange | positioned on a resin layer is synonymous with the metal foil in the said metal foil with resin, and its preferable aspect is also the same.

  The metal substrate can be manufactured, for example, as follows. On the metal support such as aluminum, the resin composition is applied and dried in the same manner as described above to form a resin layer. Further, a metal foil is disposed on the resin layer, and this is heated and pressurized. And it can manufacture by hardening | curing a resin layer. Alternatively, the metal foil with resin may be laminated on a metal support so that the resin layer faces the metal support, and then heated and pressurized to cure the resin layer. it can.

  The conditions of the heating / pressurizing treatment for curing the resin layer are appropriately selected according to the configuration of the resin composition. For example, the heating temperature is preferably 80 ° C. to 250 ° C., the pressure is preferably 0.5 MPa to 8.0 MPa, the heating temperature is 130 ° C. to 230 ° C., and the pressure is 1.5 MPa to 5.0 MPa. More preferred.

<LED board>
The LED board of the present invention is a circuit layer comprising a metal support, a cured resin layer that is a cured body of the resin composition disposed on the metal support, and a copper foil disposed on the cured resin layer. And an LED element disposed on the circuit layer.
By forming the cured resin layer having excellent adhesion, thermal conductivity, and electrical insulation on the metal support, it is possible to efficiently dissipate heat released from the LED element.

The LED substrate of the present invention includes, for example, a step of forming a circuit layer by processing a metal foil on the metal substrate obtained as described above, a step of arranging an LED element on the formed circuit layer, It can manufacture with the manufacturing method containing.
A commonly used method such as photolithography can be applied to the process of processing the metal foil on the metal substrate. Moreover, the method generally used can also be used without a restriction | limiting especially also about the process of arrange | positioning an LED element on a circuit layer.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “%” is based on mass.

(Phenolic resin synthesis example 1)
Into a 3 L separable flask equipped with a stirrer, a cooler and a thermometer, 594 g of resorcinol, 66 g of catechol, 316.2 g of 37% formalin, 15 g of oxalic acid, and 100 g of water were heated to 100 ° C. while heating in an oil bath. Warm up. The reaction was continued for 4 hours at reflux temperature.
Thereafter, the temperature in the flask was raised to 170 ° C. while distilling off water. The reaction was continued for 8 hours while maintaining 170 ° C. Thereafter, concentration was performed under reduced pressure for 20 minutes to remove water and the like in the system, and a phenol resin having a structural unit represented by the general formula (I) was taken out. The number average molecular weight of the obtained phenol resin was 530, and the weight average molecular weight was 930. The phenol equivalent of the phenol resin is 65 g / eq. Met.

<Example 1>
In a container with a TK homomixer 40L lid manufactured by PRIMIX, 2743 g of the phenol resin obtained above, 6531 g of a bifunctional epoxy resin having a biphenyl skeleton (manufactured by Mitsubishi Chemical Corporation, YL6121H, epoxy equivalent 172 g / eq.) 726 g of naphthalene-based epoxy resin (manufactured by DIC Corporation, HP4032D, epoxy equivalent 140 g / eq.) And 5250 g of 2-butanone (manufactured by Wako Pure Chemical Industries, Ltd.) as a solvent were weighed and stirred at 7000 rpm for 150 minutes.
Next, 16500 g of the solution obtained above was put into a container with a lid for planetary mixer 50L manufactured by Primix Co., Ltd., 95.3 g of silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KBM403), dispersant (manufactured by Enomoto Kasei Co., Ltd.) , ED-113) was added and stirred at 46 rpm for 10 minutes.
The alumina particles were added so that the content of the alumina particles was 74% by volume in the total solid content of the resin composition. Specifically, 54540 g (63% (total mass of alumina)) of alumina (Sumitomo Chemical Co., Ltd., Sumiko Random AA18, first alumina particle group) having a particle diameter D50 of 18 μm and a particle diameter D50 of 3 μm Alumina (Sumitomo Chemical Co., Ltd., Sumiko Random AA3, second alumina particle group) 19479 g (22.5% (total mass of alumina)) and alumina having a particle diameter D50 of 0.4 μm (Sumitomo Chemical Co., Ltd.) 12553g (14.5% (total mass of alumina)) of Sumiko Random AA04, second alumina particle group) manufactured by company was weighed and charged and stirred at 46 rpm for 30 minutes. Thereafter, 3439 g of 2-butanone (manufactured by Wako Pure Chemical Industries, Ltd.) was added as a solvent and stirred again at 46 rpm for 60 minutes, followed by filtration with a nylon mesh having an opening of 95 μm to obtain a varnish-like resin composition 1.

Using a comma coater having a gap of 80 μm, the resin composition 1 obtained above is applied on a PET film (Teijin DuPont Films, A53) at a rate of 3 m / min to form a resin layer, In a drying furnace having a furnace length of 6 m, the first half 3 m was 100 ° C., and the latter half 3 m was 120 ° C. to obtain a PET film with a resin layer. The film thickness of the resin layer after drying was 38 μm to 40 μm.
The resin layer side of a PET film with a resin layer obtained in the same manner was laminated on the resin layer after drying, and a sheet molded product (B stage sheet) was obtained at 100 ° C. and 0.3 MPa using a roll laminator. The obtained sheet molding was excellent in flexibility.

[Evaluation]
The PET film is peeled off from both sides of the sheet molded product obtained above, and the 1 mm thick aluminum substrate (the surface is jet scrubbed) and the roughened surface of 35 μm single-side roughened electrolytic copper foil (manufactured by Nippon Electrolytic Co., Ltd.) Sandwiched between. This was increased from 30 ° C. to 170 ° C. at 3 ° C. per minute in a vacuum press machine, subjected to heat and pressure treatment at 170 ° C. for 1 hour, and then rapidly cooled to room temperature. In addition, the pressure at the time of the heat and pressure treatment starts at 2 MPa, and after 100 minutes, is changed to 0.7 MPa over 5 minutes, and then the main curing treatment is performed while maintaining 0.7 MPa, and the aluminum substrate and the cured resin A metal substrate having a layer and a copper foil laminated in this order was obtained.
The following evaluation was performed about the obtained metal substrate. The evaluation results are shown in Table 1.

(Deviation rate)
The deviation rate of the actual specific gravity of the cured resin layer from the theoretical specific gravity was calculated as follows.
The copper foil and the aluminum plate of the metal substrate obtained above were removed by etching to obtain a cured resin layer. In addition, the ammonium persulfate aqueous solution was used for the etching of copper foil. Hydrochloric acid was used for etching the aluminum plate.
About the obtained cured resin layer, when the actual specific gravity of the cured resin layer was measured by the Archimedes method using the electronic hydrometer (Alpha Mirage SD-200L), it was 3.25 (g / cm < ³ >). .

On the other hand, a metal substrate was obtained in the same manner as above except that no alumina particles were added, and a cured resin layer containing no alumina particles was obtained in the same manner. It was 1.20 (g / cm < ³ >) when specific gravity was similarly measured about the obtained cured resin layer. The specific gravity of the alumina particles was 3.98 (g / cm ³ ).
The theoretical specific gravity was calculated by setting the content of alumina particles in the cured resin layer to 74% by volume and found to be 3.26 (g / cm ³ ).

When the deviation rate was calculated from the actual specific gravity and the theoretical specific gravity of the cured resin layer by the following formula, the deviation rate from the theoretical specific gravity of the actual specific gravity of the cured resin layer in the metal substrate obtained above was 0.3%. Met.
Deviation rate = (theoretical specific gravity-actual specific gravity) ÷ theoretical specific gravity

(Thermal conductivity)
The copper foil and the aluminum plate of the metal substrate obtained above were removed by etching to obtain a cured resin layer. In addition, the ammonium persulfate aqueous solution was used for the etching of copper foil. Hydrochloric acid was used for etching the aluminum plate.
The heat conductivity of the obtained heat conductive insulating layer was calculated | required as follows. First, the thermal diffusivity was determined with a thermal diffusivity measuring device (Xenon flash measurement method manufactured by Metch Co.).
Next, specific heat was measured with a differential scanning calorimeter (DSC Ryris 1 manufactured by Perkin Elmer). Further, the actual specific gravity of the cured product was measured with an electronic hydrometer (manufactured by Alpha Mirage, SD-200L).
Based on this, the thermal conductivity [W / mK] was determined from diffusivity [mm ² / s] × specific heat [J / kg · K] × actual specific gravity [g / cm ³ ]. The thermal conductivity was 5.6 W / mK.

<Electrical insulation>
The copper foil of the obtained metal substrate was etched with an aqueous ammonium persulfate solution, leaving a round pattern with a diameter of 20 mm, to prepare a measurement sample.
Next, using a dielectric breakdown voltage measuring apparatus (TOA Electronics Ltd. Japan, Puncture Tester PT-1011), 50 minimum dielectric strength voltages were measured under the condition of alternating current application (500 V / second), and the lowest measured value was obtained. The minimum dielectric breakdown voltage was used. The minimum breakdown voltage was 6.4 kV.

<Example 2>
In Example 1, 82947 g (92.0% (vs. total alumina mass)) of alumina (AS-20, particle size D50: 22 μm, manufactured by Showa Denko KK) as the first alumina particle group, and the second Except that 7212 g (8% (total mass of alumina)) of alumina (Sumitomo Chemical, Sumiko Random AA04, particle diameter D50: 0.4 μm), which is an alumina particle group, was used, was performed in the same manner as in Example 1. A varnish-like resin composition 2 was prepared and evaluated in the same manner. The evaluation results are shown in Table 1.
The actual specific gravity of the cured resin layer of the obtained metal substrate was only 2.1% different from the theoretical specific gravity of 3.26, and was excellent in thermal conductivity and dielectric breakdown voltage.

<Comparative Example 1>
In Example 1, 82947 g (92.0% (vs. total alumina mass)) of alumina (AS-30, particle size D50: 18 μm, manufactured by Showa Denko KK) as the first alumina particle group, and the second Except that 7212 g (8% (total mass of alumina)) of alumina (Sumitomo Chemical, Sumiko Random AA04, particle diameter D50: 0.4 μm), which is an alumina particle group, was used, was performed in the same manner as in Example 1. A varnish-like resin composition was prepared and evaluated in the same manner. The evaluation results are shown in Table 1.
The actual specific gravity of the cured resin layer of the obtained metal substrate was 5.5% different from the theoretical specific gravity of 3.26, which was very inferior in thermal conductivity and breakdown voltage.

<Comparative example 2>
In Example 1, 82947 g (92.0% (vs. total alumina mass)) of alumina (AS-30, particle size D50: 18 μm, manufactured by Showa Denko KK) as the first alumina particle group, and the second Except that 7212 g (8% (total mass of alumina)) of alumina (Sumitomo Chemical, Sumiko Random AA04, particle diameter D50: 0.4 μm), which is an alumina particle group, was used, was performed in the same manner as in Example 1. A varnish-like resin composition was prepared and evaluated in the same manner. The evaluation results are shown in Table 1.
The actual specific gravity of the cured resin layer of the obtained metal substrate was 10.4% different from the theoretical specific gravity of 3.26, which was very inferior in thermal conductivity and dielectric breakdown voltage.

  From Table 1, it can be seen that the cured resin obtained by curing the resin composition of the present invention is excellent in thermal conductivity and electrical insulation.

Claims (6)

A bifunctional epoxy resin having a biphenyl skeleton;
Phenolic resin,
A particle size D50 corresponding to 50% cumulative from the small particle size side of the weight cumulative particle size distribution is 0.1 μm or more and 30 μm or less, and an alumina particle group whose content is 60% by volume or more, and
A resin composition having a deviation rate from the theoretical specific gravity of the cured product within 5.0% when the cured product is used.   The alumina particle group includes a first alumina particle group having a particle diameter D50 of 7 μm or more and 30 μm or less, and at least one kind of a second alumina particle group having a particle diameter D50 of less than 7 μm. The content ratio of the first alumina particle group to the total content of the alumina particle group (first alumina particle group / second alumina particle group) is 1.0 or more and 12.0 or less on a mass basis. The resin composition as described.   A B stage sheet comprising a semi-cured product of the resin composition according to claim 1.   Metal foil with resin provided with metal foil and the semi-hardened resin layer which is a semi-hardened body of the resin composition of Claim 1 or 2 arrange | positioned on the said metal foil.   A metal support, a cured resin layer that is a cured body of the resin composition according to claim 1 or 2 disposed on the metal support, and a metal foil disposed on the cured resin layer, A metal substrate comprising:   It consists of a metal support, a cured resin layer which is a cured body of the resin composition according to claim 1 or 2 disposed on the metal support, and a metal foil disposed on the cured resin layer. An LED substrate comprising: a circuit layer; and an LED element disposed on the circuit layer.