WO2017209209A1

WO2017209209A1 - Production method for laminate

Info

Publication number: WO2017209209A1
Application number: PCT/JP2017/020342
Authority: WO
Inventors: 智雄西山; 一也木口; 竹澤　由高
Original assignee: 日立化成株式会社
Priority date: 2016-06-02
Filing date: 2017-05-31
Publication date: 2017-12-07
Also published as: TW201831330A

Abstract

A laminate production method including: a resin layer-formation step in which a resin layer is formed upon a first member separated into individual pieces; and a member arrangement step in which a second member separated into individual pieces is arranged upon the resin layer.

Description

Manufacturing method of laminate

The present invention relates to a method for manufacturing a laminate.

A laminate having a structure in which a resin layer for insulation or the like is disposed between a pair of members is used for various applications as a part of an electronic device and an electric device. Such a laminate is manufactured by cutting (separating) into a desired shape with a resin layer formed on one member, and then placing the other member on the resin layer. .

According to the study by the present inventors, in the above method, the resin layer and the member are cut in the singulation process after the resin layer is formed on one member, and the resin layer is damaged. It has been found that there is a possibility that a substance derived from this member may be mixed, a protrusion called a burr at the end of the cut surface of the member may be formed.
This invention makes it a subject to provide the novel manufacturing method of the laminated body which has a pair of member and the resin layer arrange | positioned between the said pair of member in view of the said situation.

Specific means for providing the above problems include the following embodiments.
<1> a resin layer forming step of forming a resin layer on the separated first member, and a member arranging step of arranging the separated second member on the resin layer. A manufacturing method of a layered product.
<2> The resin layer is formed by applying a resin composition to the first member, and the resin composition has a thixotropic index at a temperature when applying the resin composition to the first member. The manufacturing method of the laminated body as described in <1> which is 3 or more.
<3> The method for producing a laminate according to <1> or <2>, wherein the resin layer includes an epoxy resin.
<4> Any one of <1> to <3>, wherein the resin layer is formed using an epoxy resin composition containing two or more epoxy monomers having a mesogenic skeleton and a curing agent. The manufacturing method of the laminated body as described in any one of.
<5> The method for producing a laminate according to <4>, wherein the two or more epoxy monomers having a mesogenic skeleton include a compound represented by the following general formula (I).

[In general formula (I), R ¹ to R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ]

According to the present invention, a novel method for producing a laminate having a pair of members and a resin layer disposed between the pair of members is provided.

It is a figure which shows an example of the process of the manufacturing method of the laminated body using the 1st member which is not separated into pieces. It is a figure which shows an example of the process of the manufacturing method of the laminated body using the separated 1st member. It is a figure which shows the problem accompanying the cutting | disconnection of a resin layer and a member. It is a figure which shows an example of the laminated body manufactured by the manufacturing method of this embodiment. It is a figure which shows an example of the laminated body manufactured by the manufacturing method of this embodiment.

Hereinafter, embodiments for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, the components (including element steps and the like) are not essential unless otherwise specified. The same applies to numerical values and ranges thereof, and the present invention is not limited thereto.
In this specification, the term “process” includes a process that is independent of other processes and includes the process if the purpose of the process is achieved even if it cannot be clearly distinguished from the other processes. It is.
In the present specification, numerical values indicated by using “to” include numerical values described before and after “to” as the minimum value and the maximum value, respectively.
In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another numerical range. Good. Further, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.
In the present specification, the content of each component in the composition is the sum of the plurality of substances present in the composition unless there is a specific indication when there are a plurality of substances corresponding to each component in the composition. It means the content rate of.
In the present specification, the particle diameter of each component in the composition is a mixture of the plurality of types of particles present in the composition unless there is a specific indication when there are a plurality of types of particles corresponding to each component in the composition. Means the value of.
In this specification, the term “layer” or “film” refers to a part of the region in addition to the case where the layer or the film is formed when the region where the layer or film exists is observed. It is also included when it is formed only.
In this specification, the term “lamination” indicates that layers are stacked, and two or more layers may be combined, or two or more layers may be detachable.
In the present specification, the “number of structural units” indicates an integer value for a single molecule, but a rational number that is an average value as an aggregate of a plurality of types of molecules.
For the definition of “B stage” in this specification, refer to the provisions of JIS K6900: 1994.
In this specification, for the definition of the surface roughness (Rz), refer to the definition of (Rzjis) in JIS B 0601-2001.

<Method for producing laminate>
The manufacturing method of the laminated body of this embodiment arrange | positions the resin layer formation process which forms a resin layer on the separated 1st member, and the 2nd member separated on the said resin layer. A member arranging step.

In the present specification, the first member and the second member are “separated” means that the size and shape of each member before forming the resin layer is the size of each member in the finally obtained laminate. It means that it becomes the shape and shape.

The manufacturing method of the laminated body of this embodiment is demonstrated with reference to drawings. However, the size of the members in each drawing is conceptual, and the relative relationship between the sizes of the members is not limited to this.

FIG. 1 shows an example of the steps of a method for manufacturing a laminate using a first member that is not separated. First, the first member 1 for forming the resin layer is prepared (FIG. 1A), and the resin layer 2 is formed thereon (FIG. 1B). When the resin layer 2 contains a volatile component such as a solvent, the volatile component is removed (FIG. 1C), and the resin layer 2 is sandwiched between the pair of

hot plates

3 and 4 and heated (FIG. 1D). Thereafter, the first member 1 in a state where the resin layer 2 is formed is cut (divided) into a predetermined size (FIG. 1 (e)). Then, the 2nd member 5 is arrange | positioned on the resin layer 2, and it heats, pressing between a pair of

hot plates

6 and 7 in this state (FIG.1 (f)).

Next, FIG. 2 shows an example of a process of a laminate manufacturing method (corresponding to the laminate manufacturing method of the present embodiment) using the separated first member. First, the first member 1 for forming the resin layer is prepared (FIG. 1A) and cut (divided) into a predetermined size (FIG. 1B). Next, the resin layer 2 is formed on the first member 1 (FIG. 1C). When the resin layer 2 contains a volatile component such as a solvent, the volatile component is removed (FIG. 1 (d)), and the resin layer 2 is sandwiched between a pair of

hot plates

3 and 4 and heated (FIG. 1 (e)). Then, the 2nd member 5 is arrange | positioned on the resin layer 2, and it heats, pressing between a pair of

hot plates

6 and 7 in this state (FIG.1 (f)).

If the above manufacturing methods are compared, in the manufacturing method of the laminated body of this embodiment, a laminated body is manufactured without passing through the process of cutting a resin layer and a member. Therefore, it is possible to avoid various problems associated with the cutting of the resin layer and the member. Moreover, since a cutting process is not passed from the formation of the resin layer to obtaining the laminate, it is advantageous in terms of productivity.

Problems that may occur when the resin layer and the member are cut will be described with reference to FIG. First, when the first member 1 is cut in a state where the resin layer 2 is formed on the first member 1, a burr 10 is generated along the cut surface of the first member 1. In addition to causing burrs, the burrs 10 may interfere with the arrangement of the laminated body in the press device in parallel when performing press bonding or the like in the next process, and the adhesion between each member and the resin layer may be impaired. . Moreover, the crack 11 arises in the resin layer 2, and when a high voltage is applied to a laminated body, the crack 11 may be a starting point and may lead to a dielectric breakdown from a partial discharge. Furthermore, the cutting waste 12 of the first member 1 and the cutting waste 13 of the resin layer 2 are generated to prevent the resin layer 2 from entering the surface irregularities of the first member 1, thereby reducing the adhesiveness of the resin layer 2 and insulating properties. There is a possibility of worsening. If the cutting waste 12 of the first member 1 is a conductive substance such as metal, it may become a conductive foreign substance and adversely affect the insulation of the resin layer 2.

The laminate manufactured by the manufacturing method of the present embodiment is not particularly limited as long as at least the first member, the resin layer, and the second member are arranged in this order. For example, as shown in FIG. 5, even when the resin layer 2 is formed only on the first member 1 as shown in FIG. 4 and the second member 5 is arranged so as to be in contact with the resin layer 2 to produce a laminate, A resin layer 2 is formed on each of the first member 1 and the second member 2, and a laminated body is manufactured by arranging the resin layer 2 of the first member 1 and the resin layer 2 of the second member 5 to face each other. May be.

In the resin layer forming step, a resin layer is formed on the first member. The method for forming the resin layer is not particularly limited, and methods such as coating, printing, and transfer can be applied depending on the application. From the viewpoint of improving the adhesion of the resin layer to the first member, it is preferable to form the resin layer using a liquid resin composition. When the resin layer is formed using a liquid resin composition, the followability of the resin composition to the unevenness of the surface of the first member is improved, and the adhesion of the resin layer to the first member tends to be increased.

In the present specification, the “liquid resin composition” means a resin composition that is liquid at least when applied to the first member. The liquid level is not particularly limited, and can be selected according to the surface state of the first member, the method of applying the resin composition, and the like. For example, the viscosity when applying the resin composition to the first member is preferably 10 Pa · s or less. The viscosity of the resin composition is a value measured at 5 min ⁻¹ (rpm) using (Toki Sangyo Co., Ltd., TV-33) at the temperature at which the resin composition is applied to the first member.

When the resin layer is formed using a liquid resin composition, the composition is not particularly limited, and the resin layer alone may contain a component that adjusts the viscosity such as a solvent. When the resin composition contains a solvent, the solvent may be removed by drying or the like after the resin composition is applied on the first member.

From the viewpoint of forming the resin layer at a predetermined position of the singulated first member, it is preferable to form the resin layer by applying a resin composition having excellent shape retention to the first member. For example, it is preferable to use a resin composition having a thixotropic index of 1 or more at the temperature at which the resin composition is applied to the first member. From the viewpoint of achieving both good coatability and shape retention, it is more preferable to use a resin composition having a thixotropic index of 1 to 10 at the temperature when the resin composition is applied to the first member. .

In the present specification, the thixotropic index of the resin composition is 5 min ⁻¹ using a E-type viscometer (Toki Sangyo Co., Ltd., TV-33) at the temperature at which the resin composition is applied to the first member. The ratio of viscosity B (Pa · s) measured at 0.5 min ⁻¹ (rpm) to viscosity A (Pa · s) measured at rpm) (viscosity B / viscosity A).

From the viewpoint of workability in the step after forming the resin layer on the first member, the resin layer forming step preferably includes a step of heating the resin layer. By heating the resin layer, volatile components such as a solvent contained in the resin layer are efficiently removed. When the heating is performed, the resin component in the resin layer reacts to increase the viscosity, and the followability to the second member is reduced to some extent. However, in the method of this embodiment, the second member having a small surface roughness is used as the resin layer. Therefore, good adhesion can be ensured.

The method of heating the resin layer is not particularly limited, but a method of bringing the resin layer into a B-stage state is preferable. The method and conditions for bringing the resin layer into the B stage state are not particularly limited. From the viewpoint of forming a resin layer having a smooth surface and reduced thickness unevenness, a method of heating while pressing the first member and the resin layer formed thereon with a pair of hot plates is preferable.

In the member placement step, the second member is placed on the resin layer formed on the first member. The method for arranging the second member is not particularly limited.

After disposing the second member on the resin layer formed on the first member, the resin layer is cured to obtain a laminate. The method for curing the resin layer is not particularly limited. For example, the second member may be sandwiched between a pair of hot plates in a state where the second member is disposed on the resin layer and heated while being pressed.

The manufacturing method of the laminated body of this embodiment may satisfy | fill at least one of following conditions (1) and (2).
(1) The surface roughness (Rz) of the surface in contact with the resin layer of the first member is larger than the surface roughness (Rz) of the surface in contact with the resin layer of the second member.
(2) The surface roughness (Rz) of the surface in contact with the resin layer of the second member is 30 μm or less.

When the manufacturing method of the laminated body of this embodiment satisfy | fills conditions (1), even if the followability to the surface shape of the 2nd member of the resin layer formed on the 1st member has fallen, followability falls. The resin layer before being formed is formed on the first member having the larger surface roughness, and the second member having the smaller surface roughness is disposed on the resin layer after the followability is lowered. By making the order which makes a 1st member and a 2nd member and a resin layer contact as mentioned above, the laminated body which is excellent in the adhesiveness of the resin layer with respect to each member can be obtained.

When the manufacturing method of the laminated body of the present embodiment satisfies the condition (2), even if the followability to the surface shape of the second member of the resin layer formed on the first member is reduced, the second member Adequate adhesion is obtained when the surface roughness (Rz) of the surface in contact with the resin layer is 30 μm or less.

In the manufacturing method of the laminated body of this embodiment, the material of the first member and the second member is not particularly limited, and examples thereof include metals, semiconductors, glasses, resins, and composites thereof. The shape in particular of a 1st member and a 2nd member is not restrict | limited, A board, foil, a film, etc. are mentioned. The material and shape of the first member and the second member may be the same or different. The magnitude | size of the 1st and 2nd member of the state separated into pieces is not restrict | limited in particular, It can select according to the use of a laminated body. For example, the area may be in the range of 1 cm ² to 200 cm ² .

The first member and the second member may be subjected to a surface roughening treatment. In general, as the surface roughness of the surface where the member is in contact with the resin layer is larger, the anchor effect that is manifested by the resin layer entering into the irregularities on the surface of the member increases, and the adhesive strength tends to increase. As a result, it can be expected to improve the shear strength for evaluating the adhesive force mainly applied in the planar direction of the resin layer, and the peel strength for evaluating the adhesive force mainly applied in the vertical direction of the resin layer. In addition, it is preferable that there is little generation | occurrence | production of a void when joining a member and a resin layer, and it is more preferable that it can contact | adhere without generation | occurrence | production of a void. If the generation of voids when joining the member and the resin layer is small, the insulation tends to be improved.

The member subjected to the surface roughening treatment may be obtained using a material having a rough surface or may be obtained by roughening a material having a smooth surface. The surface roughening treatment method is not particularly limited, and may be performed by a physical method or a chemical method. Physical methods include file processing, sandblasting, laser irradiation, and the like. Examples of the chemical treatment include magnesium treatment, CZ treatment, blackening treatment, etching treatment and the like when the material is copper. When the material is aluminum, alumite treatment is exemplified. The method of surface treatment is not limited to these, and physical treatment or chemical treatment is performed alone, physical treatment and chemical treatment are combined, or two or more chemical treatments are combined. Or two or more physical processes may be combined.

The surface which contacts the resin layer of the first member and the second member may be provided with a surface treatment agent. Surface treatment agents include solid or liquid thermosetting resin monomer coating and thermoplastic resin solvent coating, silanol coupling agent, titanate coupling agent, aluminosilicate agent, leveling for the purpose of improving the wettability of the resin. And surface protecting agents such as agents.

The type of resin contained in the resin layer is not particularly limited. Examples thereof include thermosetting resins such as epoxy resins, phenol resins, urea resins, melamine resins, urethane resins, silicone resins, and unsaturated polyester resins. The resin contained in the resin layer may be one type or two or more types. From the viewpoint of electrical insulation and adhesiveness, the resin layer preferably contains an epoxy resin. The resin layer may contain a component other than the resin such as a filler as necessary.

The thickness of the resin layer is not particularly limited. From the viewpoint of sufficiently obtaining the effects (insulating properties, etc.) obtained by providing the resin layer, the larger the thickness, the better. From the viewpoint of manufacturing cost, thermal conductivity, etc., the smaller the thickness, the better. For example, it may be in the range of 80 μm to 300 μm. In this specification, the thickness of the resin layer can be measured by a known method, and the arithmetic average value of the values measured at five points is used.

The use of the laminate manufactured by the manufacturing method of the present embodiment is not particularly limited. For example, a semiconductor device can be given. Among semiconductor devices, it is suitably used for components with particularly high heat generation density.

<Epoxy resin composition>
You may form the resin layer of the laminated body obtained by the manufacturing method of this embodiment using the epoxy resin composition containing an epoxy monomer and a hardening | curing agent.

[Epoxy monomer]
The epoxy monomer contained in the epoxy resin composition may be one type alone or two or more types. Moreover, what the epoxy monomer was in the state of the oligomer or the prepolymer may be included.

The type of epoxy monomer is not particularly limited, and can be selected according to the use of the laminate. When the resin layer is required to have high thermal conductivity, an epoxy monomer having a mesogenic skeleton and having two glycidyl groups in one molecule (hereinafter also referred to as a specific epoxy monomer) may be used. A resin layer formed using an epoxy resin composition containing a specific epoxy monomer tends to exhibit high thermal conductivity.

In the present specification, the “mesogen skeleton” indicates a molecular structure that may exhibit liquid crystallinity. Specific examples include a biphenyl skeleton, a phenylbenzoate skeleton, an azobenzene skeleton, a stilbene skeleton, and derivatives thereof. An epoxy resin composition containing an epoxy monomer having a mesogenic skeleton tends to form a higher-order structure at the time of curing and tends to achieve higher thermal conductivity when a cured product is produced.

Specific epoxy monomers include, for example, biphenyl type epoxy monomers and tricyclic type epoxy monomers. The specific epoxy monomer contained in the epoxy resin composition may be one kind alone or two or more kinds. Moreover, what the specific epoxy monomer was in the state of the oligomer or the prepolymer may be included.

Biphenyl type epoxy monomers include 4,4'-bis (2,3-epoxypropoxy) biphenyl, 4,4'-bis (2,3-epoxypropoxy) -3,3 ', 5,5'-tetramethyl An epoxy monomer obtained by reacting biphenyl, epichlorohydrin and 4,4′-biphenol or 4,4 ′-(3,3 ′, 5,5′-tetramethyl) biphenol, α-hydroxyphenyl-ω-hydropoly ( Biphenyldimethylene-hydroxyphenylene) and the like. Biphenyl type epoxy resins are named according to product names such as “YX4000”, “YL6121H” (Mitsubishi Chemical Corporation), “NC-3000”, “NC-3100” (Nippon Kayaku Co., Ltd.). The thing marketed is mentioned.

Examples of the tricyclic epoxy monomer include epoxy monomers having a terphenyl skeleton, 1- (3-methyl-4-oxiranylmethoxyphenyl) -4- (4-oxiranylmethoxyphenyl) -1-cyclohexene, 1- Examples include (3-methyl-4-oxiranylmethoxyphenyl) -4- (4-oxiranylmethoxyphenyl) -benzene, compounds represented by the following general formula (I), and the like.

From the viewpoint of achieving higher thermal conductivity, the specific epoxy monomer is preferably capable of forming a higher order structure and capable of forming a smectic structure when used alone as an epoxy monomer and cured. Is more preferable. Examples of such an epoxy monomer include compounds represented by the following general formula (I). When the epoxy resin composition contains a compound represented by the following general formula (I), higher thermal conductivity can be achieved.

In general formula (I), R ¹ to R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹ to R ⁴ are each independently preferably a hydrogen atom or an alkyl group having 1 or 2 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom. In addition, 2 to ⁴ of R ¹ to R ⁴ are preferably hydrogen atoms, more preferably 3 or 4 are hydrogen atoms, and all 4 are further hydrogen atoms. preferable. When any of R ¹ to R ⁴ is an alkyl group having 1 to 3 carbon atoms, at least one of R ¹ and R ⁴ is preferably an alkyl group having 1 to 3 carbon atoms.

Incidentally, preferred examples of the compound represented by the general formula (I) are described in, for example, JP-A-2011-74366. Specifically, compounds represented by the general formula (I) include 4- {4- (2,3-epoxypropoxy) phenyl} cyclohexyl = 4- (2,3-epoxypropoxy) benzoate and 4- {4 Preferred is at least one compound selected from the group consisting of-(2,3-epoxypropoxy) phenyl} cyclohexyl = 4- (2,3-epoxypropoxy) -3-methylbenzoate.

Here, the higher order structure is a state in which the constituent elements are arranged microscopically, and corresponds to, for example, a crystal phase and a liquid crystal phase. Whether or not such a higher-order structure exists can be easily determined by observation with a polarizing microscope. That is, when an interference pattern due to depolarization is observed in the observation in the crossed Nicol state, it can be determined that a higher order structure exists. The higher order structure usually exists in an island shape in the resin, and forms a domain structure. Each island forming the domain structure is called a higher-order structure. The structural units constituting the higher order structure are generally bonded by a covalent bond.

High-order structures with high regularity derived from the mesogenic skeleton include nematic structures and smectic structures. The nematic structure is a liquid crystal structure in which the molecular long axis is oriented in a uniform direction and has only alignment order. On the other hand, the smectic structure is a liquid crystal structure having a one-dimensional positional order in addition to the orientation order and having a layer structure with a constant period. In addition, the direction of the period of the layer structure is uniform inside the structure having the same period of the smectic structure. That is, the order of molecules is higher in the smectic structure than in the nematic structure. When a highly ordered higher-order structure is formed in a semi-cured product or a cured product, it is possible to suppress scattering of phonons that are heat conductive media. For this reason, the smectic structure has a higher thermal conductivity than the nematic structure.
That is, the order of the molecule is higher in the smectic structure than in the nematic structure, and the thermal conductivity of the cured product is higher in the case of showing the smectic structure. Since the epoxy resin composition containing the compound represented by the general formula (I) can react with a curing agent to form a smectic structure, it is considered that high thermal conductivity can be exhibited.

Whether or not a smectic structure can be formed using the epoxy resin composition can be determined by the following method.
X-ray diffraction measurement is performed using an X-ray analyzer (for example, manufactured by Rigaku Corporation) using a CuK _α 1 line and a tube voltage of 40 kV, a tube current of 20 mA, and 2θ in the range of 0.5 ° to 30 °. When a diffraction peak exists in the range of 2θ of 1 ° to 10 °, it is determined that the periodic structure includes a smectic structure. Note that in the case of a highly ordered high-order structure derived from a mesogenic structure, a diffraction peak appears in the range of 2θ of 1 ° to 30 °.

The epoxy resin composition contains two or more types of specific epoxy monomers and a curing agent, and the two or more types of specific epoxy monomers are compatible with each other, and react with the curing agent to form a smectic structure. An epoxy resin composition that can be formed (hereinafter, also referred to as “specific epoxy resin composition”) may be used. The specific epoxy resin composition has a low melting point and excellent thermal conductivity after curing.

In the present specification, “two or more types of epoxy monomers” mean two or more types of epoxy monomers having different molecular structures. However, epoxy monomers having a stereoisomer (optical isomer, geometric isomer, etc.) relationship do not fall under “two or more epoxy monomers” and are regarded as the same type of epoxy monomer.

The reason why the specific epoxy resin composition has a low melting point and excellent thermal conductivity after curing is not clear, but two or more specific epoxy monomers are compatible with each other to form a smectic structure. It is considered that the melting point of the previous specific epoxy resin composition can be lowered and high thermal conductivity can be exhibited after curing.

The specific epoxy resin composition contains two or more specific epoxy monomers, and the specific epoxy monomers are compatible with each other. The melting point of a mixture of two or more types of specific epoxy monomers compatible with each other (hereinafter also referred to as “epoxy monomer mixture”) is the specific epoxy having the highest melting point among the specific epoxy monomers constituting the epoxy monomer mixture. There is a phenomenon that the melting point of the monomer becomes lower. Therefore, it becomes possible to exhibit the low melting point of the specific epoxy resin composition.
In addition, the thermal conductivity when the specific epoxy resin composition is semi-cured or cured is higher than the thermal conductivity when the specific epoxy monomer alone constituting the epoxy monomer mixture is semi-cured or cured. It becomes possible to do.
When the epoxy monomer mixture includes three or more types of specific epoxy monomers, it is sufficient that the epoxy monomer mixture composed of all the specific epoxy monomers constituting the epoxy monomer mixture is compatible as a whole. Any two selected specific epoxy monomers may not be compatible with each other.

In this specification, “compatible” means phase separation derived from a specific epoxy monomer when the specific epoxy resin composition is semi-cured or cured after the epoxy monomer mixture is melted and naturally cooled. Means that no condition is observed. Moreover, even if each specific epoxy monomer is phase-separated in the epoxy monomer mixture before making a semi-cured product or a cured product, when a phase-separated state is not observed when making a semi-cured product or a cured product, It is determined that the specific epoxy monomers contained in the monomer mixture are compatible with each other.

In the present specification, “specific epoxy monomers are compatible with each other” means that the specific epoxy monomers constituting the epoxy monomer mixture are not phase-separated at the curing temperature of the specific epoxy resin composition. It means that it is possible.

Whether or not the specific epoxy monomers are compatible with each other can be determined by the presence or absence of a phase separation state when the specific epoxy resin composition is made into a semi-cured product or a cured product. For example, it can be judged by observing a semi-cured product or a cured product of a specific epoxy resin composition at a curing temperature described later using an optical microscope. More specifically, the determination can be made by the following method. The epoxy monomer mixture is melted by heating above the temperature at which the epoxy monomer mixture transitions to the isotropic phase, and then the molten epoxy monomer mixture is allowed to cool naturally. In this process, an optical microscopic image of the semi-cured product or cured product of the specific epoxy resin composition at the temperature at which the semi-cured product or cured product is formed using the specific epoxy resin composition, that is, the curing temperature (magnification: 100 times) and observing whether each specific epoxy monomer contained in the epoxy monomer mixture is phase-separated.

The curing temperature can be appropriately selected according to the specific epoxy resin composition. The curing temperature is preferably 100 ° C. or higher, more preferably 100 ° C. to 250 ° C., and still more preferably 120 ° C. to 210 ° C.

In addition to the above method, whether or not specific epoxy monomers are compatible with each other is examined by observing a semi-cured product or a cured product derived from the epoxy monomer mixture using a scanning electron microscope (SEM). be able to. After cutting a semi-cured product or a cured product cross section derived from the epoxy monomer mixture with, for example, a diamond cutter, it is polished with abrasive paper and slurry, and the state of the cross section is, for example, 2000 times using SEM. Observe at magnification. In the case of a semi-cured product or a cured product derived from an epoxy monomer mixture comprising a combination of epoxy monomers that undergo phase separation, it can be observed that the phases are separated.

In addition, the melting point of the epoxy monomer mixture composed of the specific epoxy monomers in a compatible combination is lower than the melting point of the specific epoxy monomer having the highest melting point among the specific epoxy monomers constituting the epoxy monomer mixture. . As used herein, the melting point refers to the temperature at which an epoxy monomer undergoes a phase transition from a liquid crystal phase to an isotropic phase in an epoxy monomer having a liquid crystal phase. In addition, in the case of an epoxy monomer having no liquid crystal phase, it indicates the temperature at which the state of the substance changes from a solid (crystalline phase) to a liquid (isotropic phase).
The liquid crystal phase is one of the phases located between the crystalline state (crystalline phase) and the liquid state (isotropic phase). Although the molecular orientation direction maintains some order, it is in a three-dimensional position. It refers to the state that lost order.

The presence or absence of a liquid crystal phase can be determined by a method of observing a change in the state of a substance in the process of raising the temperature from room temperature (for example, 25 ° C.) using a polarizing microscope. In the observation in the crossed Nicols state, interference fringes due to depolarization are seen in the crystal phase and the liquid crystal phase, and the isotropic phase appears in the dark field. The transition from the crystal phase to the liquid crystal phase can be confirmed by the presence or absence of fluidity. In other words, the expression of the liquid crystal phase means that the liquid crystal phase has a fluidity and has a temperature region where interference fringes due to depolarization are observed.
That is, in the observation in the crossed Nicol state, if it is confirmed that the specific epoxy monomer or the epoxy monomer mixture has fluidity and has a temperature region where interference fringes due to depolarization are observed, the specific epoxy monomer Alternatively, it is determined that the epoxy monomer mixture has a liquid crystal phase.

When the epoxy monomer mixture has a liquid crystal phase, the temperature range is preferably 10 ° C. or higher, more preferably 20 ° C. or higher, and further preferably 40 ° C. or higher. When the temperature region is 10 ° C. or higher, high thermal conductivity tends to be achieved. Furthermore, the wider the temperature region, the higher the thermal conductivity, which is preferable.

The melting point of the specific epoxy monomer or epoxy monomer mixture can be determined by using a differential scanning calorimeter (DSC) in a temperature range from 25 ° C. to 350 ° C. under a temperature rising rate of 10 ° C./min. It is measured as a temperature at which an energy change (endothermic reaction) occurs with a phase transition. When the melting point of the specific epoxy monomer or the epoxy monomer mixture is 120 ° C. or higher, it is not preferable from the viewpoint of workability and reactivity.

When the specific epoxy monomers are compatible with each other, that is, when the specific epoxy monomers are not phase-separated from each other in the semi-cured product or the cured product derived from the epoxy monomer mixture, Even when a specific epoxy resin composition is configured by adding an inorganic filler or the like contained as necessary, in a semi-cured product or a cured product of the specific epoxy resin composition, the specific epoxy monomers are not phase-separated from each other. Become.

The two or more types of specific epoxy monomers contained in the specific epoxy resin composition are compatible with each other, and are not particularly limited as long as they can form a smectic structure by reacting with a curing agent described later. It can be selected from epoxy monomers having a skeleton. For example, the specific epoxy monomer can be selected from those exemplified above.

The specific epoxy resin composition is different from the compound represented by the general formula (I) and the compound represented by the general formula (I) as two or more kinds of specific epoxy monomers, and is represented by the general formula (I). It is preferable to contain a specific epoxy monomer that is compatible with the compound (hereinafter referred to as “specific epoxy monomer different from the compound represented by the general formula (I)”). The epoxy resin composition contains a compound represented by the general formula (I) and a specific epoxy monomer different from the compound represented by the general formula (I), thereby effectively reducing the melting point and heat conductivity. It is possible to achieve both improvements.

As a mixing ratio of the compound represented by the general formula (I) and the specific epoxy monomer different from the compound represented by the general formula (I), a viewpoint of achieving both low melting point and improved thermal conductivity. To an epoxy equivalent number ratio of 5: 5 to 9.5: 0.5 (a compound represented by the general formula (I): a specific epoxy monomer different from the compound represented by the general formula (I)). Preferably, it is in the range of 6: 4 to 9: 1, more preferably in the range of 7: 3 to 9: 1.

The content of the specific epoxy monomer in the epoxy monomer mixture is not particularly limited as long as it can form a smectic structure by reaction between the epoxy monomer mixture and a curing agent described later, and can be selected as appropriate. From the viewpoint of lowering the melting point, the content of the specific epoxy monomer is preferably 5% by mass or more, more preferably 10% by mass to 90% by mass, more preferably 100% by mass with respect to the total mass of the epoxy monomer mixture. % Is more preferable.

The total content of the specific epoxy monomer in the epoxy resin composition is not particularly limited. From the viewpoint of thermosetting and thermal conductivity, the total content of the specific epoxy monomer is preferably 3% by mass to 10% by mass with respect to the total mass of the epoxy resin composition, and 3% by mass to 8% by mass. It is more preferable that

[Curing agent]
The epoxy resin composition contains a curing agent. The curing agent is not particularly limited as long as it is a compound capable of curing reaction with a specific epoxy monomer, and a commonly used curing agent can be appropriately selected and used. Specific examples of the curing agent include acid anhydride curing agents, amine curing agents, phenol curing agents, polyaddition curing agents such as mercaptan curing agents, and catalytic curing agents such as imidazole. These curing agents may be used alone or in combination of two or more.
Among these, from the viewpoint of heat resistance, it is preferable to use at least one selected from the group consisting of amine-based curing agents and phenol-based curing agents, and from the viewpoint of storage stability, phenol-based curing agents. More preferably, at least one of the above is used.

As the amine-based curing agent, those usually used as curing agents for epoxy monomers can be used without particular limitation, and commercially available ones may be used. Among these, from the viewpoint of curability, the amine curing agent is preferably a polyfunctional curing agent having two or more functional groups, and from the viewpoint of thermal conductivity, is a polyfunctional curing agent having a rigid skeleton. It is more preferable.

Specific examples of the bifunctional amine curing agent include 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfone, 4,4′-diamino-3,3. Examples include '-dimethoxybiphenyl, 4,4'-diaminophenyl benzoate, 1,5-diaminonaphthalene, 1,3-diaminonaphthalene, 1,4-diaminonaphthalene, 1,8-diaminonaphthalene and the like.
Among these, from the viewpoint of thermal conductivity, it is preferably at least one selected from the group consisting of 4,4′-diaminodiphenylmethane, 1,5-diaminonaphthalene and 4,4′-diaminodiphenylsulfone, More preferred is 5-diaminonaphthalene.

As a phenol type hardening | curing agent, what is normally used as a hardening | curing agent of an epoxy monomer can be especially used without a restriction | limiting, You may use what is marketed. For example, phenol and a novolac phenol resin can be used.
Examples of the phenol curing agent include monofunctional compounds such as phenol, o-cresol, m-cresol, and p-cresol; bifunctional compounds such as catechol, resorcinol, and hydroquinone; 1,2,3-trihydroxybenzene, 1, And trifunctional compounds such as 2,4-trihydroxybenzene and 1,3,5-trihydroxybenzene. Further, as the curing agent, a phenol novolak resin obtained by connecting these phenol curing agents with a methylene chain or the like to form a novolak can be used.

Specific examples of the phenol novolak resin include resins obtained by novolacizing one phenol compound such as cresol novolak resin, catechol novolak resin, resorcinol novolak resin, hydroquinone novolak resin; catechol resorcinol novolak resin, resorcinol hydroquinone novolak resin, etc. Examples thereof include resins obtained by novolacizing two or more phenol compounds.

When a phenol novolak resin is used as the phenolic curing agent, the phenol novolak resin has a structural unit represented by at least one selected from the group consisting of the following general formulas (II-1) and (II-2) It is preferable to include a compound.

In general formula (II-1) and general formula (II-2), R ²¹ and R ²⁴ each independently represents an alkyl group, an aryl group or an aralkyl group. R ²² , R ²³ , R ²⁵ and R ²⁶ each independently represent a hydrogen atom, an alkyl group, an aryl group or an aralkyl group. m21 and m22 each independently represents an integer of 0-2. n21 and n22 each independently represents an integer of 1 to 7.

The alkyl group may be linear, branched or cyclic.
The aryl group may have a structure containing a hetero atom in the aromatic ring. In this case, a heteroaryl group in which the total number of heteroatoms and carbon is 6 to 12 is preferable.
The alkylene group in the aralkyl group may be any of a chain, a branched chain, and a cyclic group. The aryl group in the aralkyl group may have a structure containing a hetero atom in the aromatic ring. In this case, a heteroaryl group in which the total number of heteroatoms and carbon is 6 to 12 is preferable.

In the general formula (II-1) and general formula (II-2), R ²¹ and R ²⁴ each independently represents an alkyl group, an aromatic group (aryl group), or an aralkyl group. These alkyl group, aromatic group and aralkyl group may further have a substituent if possible. Examples of the substituent include an alkyl group (except when R ²¹ and R ²⁴ are alkyl groups), an aromatic group, a halogen atom, and a hydroxyl group.
m21 and m22 each independently represents an integer of 0 to 2, and when m21 or m22 is 2, two R ²¹ or R ²⁴ may be the same or different. m21 and m22 are each independently preferably 0 or 1, and more preferably 0.
n21 and n22 are the numbers of structural units represented by the above general formulas (II-1) and (II-2) contained in the phenol novolac resin, and each independently represents an integer of 1 to 7.

In the above general formula (II-1) and general formula (II-2), R ²² , R ²³ , R ²⁵ and R ²⁶ each independently represent a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group. The alkyl group, aryl group and aralkyl group represented by R ²² , R ²³ , R ²⁵ and R ²⁶ may further have a substituent, if possible. Examples of the substituent include an alkyl group (provided that R ²² , R ²³ , R ²⁵ and R ²⁶ are alkyl groups), an aryl group, a halogen atom, a hydroxyl group and the like.

In general formula (II-1) and general formula (II-2), R ²² , R ²³ , R ²⁵ and R ²⁶ are each independently a hydrogen atom, an alkyl group, from the viewpoint of storage stability and thermal conductivity, Alternatively, it is preferably an aryl group, more preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and further preferably a hydrogen atom.
Furthermore, from the viewpoint of heat resistance, at least one of R ²² and R ²³ is preferably an aryl group, more preferably an aryl group having 6 to 12 carbon atoms. Similarly, at least one of R ²⁵ and R ²⁶ is preferably an aryl group, and more preferably an aryl group having 6 to 12 carbon atoms.
The aryl group may have a structure containing a hetero atom in the aromatic ring. In this case, a heteroaryl group in which the total number of heteroatoms and carbon is 6 to 12 is preferable.

The phenolic curing agent may contain one type of compound having the structural unit represented by the above general formula (II-1) or general formula (II-2) alone, or may contain two or more types. Preferably, it contains at least one compound having a structural unit derived from resorcinol represented by the general formula (II-1).

The compound having the structural unit represented by the general formula (II-1) may further include at least one partial structure derived from a phenol compound other than resorcinol. In the above general formula (II-1), examples of the partial structure derived from a phenol compound other than resorcinol include phenol, cresol, catechol, hydroquinone, 1,2,3-trihydroxybenzene, 1,2,4-trimethyl. Examples thereof include partial structures derived from hydroxybenzene and 1,3,5-trihydroxybenzene. The partial structures derived from these may be contained singly or in combination of two or more.
In addition, the compound having the structural unit represented by the general formula (II-2) may include at least one partial structure derived from a phenol compound other than catechol. In the general formula (II-2), examples of the partial structure derived from a phenol compound other than catechol include, for example, phenol, cresol, resorcinol, hydroquinone, 1,2,3-trihydroxybenzene, 1,2,4-trimethyl. Examples thereof include partial structures derived from hydroxybenzene and 1,3,5-trihydroxybenzene. The partial structures derived from these may be contained singly or in combination of two or more.

Here, the partial structure derived from the phenol compound means a monovalent or divalent group constituted by removing one or two hydrogen atoms from the benzene ring portion of the phenol compound. The position where the hydrogen atom is removed is not particularly limited.

In the compound having the structural unit represented by the general formula (II-1), the content of the partial structure derived from resorcinol is not particularly limited. From the viewpoint of the elastic modulus, the content of the partial structure derived from resorcinol is preferably 55% by mass or more based on the total mass of the compound having the structural unit represented by the general formula (II-1), and the glass transition temperature From the viewpoint of (Tg) and the linear expansion coefficient, it is more preferably 80% by mass or more, and from the viewpoint of thermal conductivity, it is further preferably 90% by mass or more.

Further, the phenol novolac resin more preferably includes a novolac resin having a partial structure represented by at least one selected from the group consisting of the following general formulas (III-1) to (III-4).

In the general formulas (III-1) to (III-4), m31 to m34 and n31 to n34 each independently represent a positive integer and represent the number of each structural unit contained. Ar ³¹ to Ar ³⁴ each independently represent a group represented by the following general formula (III-a) or a group represented by the following general formula (III-b).

In general formula (III-a) and general formula (III-b), R ³¹ and R ³⁴ each independently represent a hydrogen atom or a hydroxyl group. R ³² and R ³³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.

A curing agent having a partial structure represented by at least one of general formula (III-1) to general formula (III-4) is produced as a by-product by a production method described later in which a divalent phenol compound is novolakized. It can be generated.

The partial structures represented by the general formulas (III-1) to (III-4) may be included as the main chain skeleton of the compound, or may be included as a part of the side chain. Furthermore, each structural unit constituting the partial structure represented by any one of the above general formulas (III-1) to (III-4) may be included randomly or regularly. It may be contained in a block shape. In the above general formulas (III-1) to (III-4), the hydroxyl substitution position is not particularly limited as long as it is on the aromatic ring.

For each of the general formulas (III-1) to (III-4), a plurality of Ar ³¹ to Ar ³⁴ may all be the same atomic group or include two or more atomic groups. Also good. Ar ³¹ to Ar ³⁴ each independently represents a group represented by any one of the above general formulas (III-a) and (III-b).

In formulas (III-a) and (III-b), R ³¹ and R ³⁴ are each independently a hydrogen atom or a hydroxyl group, but are preferably a hydroxyl group from the viewpoint of thermal conductivity. Further, the substitution positions of R ³¹ and R ³⁴ are not particularly limited.

R ³² and R ³³ in the above general formula (III-a) and general formula (III-b) each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms in R ³² and R ³³ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, and an n-pentyl group. , N-hexyl group, n-heptyl group, and n-octyl group. In addition, the substitution positions of R ³² and R ³³ in general formula (III-a) and general formula (III-b) are not particularly limited.

Ar ³¹ to Ar ³⁴ in the general formula (III-a) and the general formula (III-b) are groups derived from dihydroxybenzene (in the general formula (III-a), from the viewpoint of achieving higher thermal conductivity. A group wherein R ³¹ is a hydroxyl group and R ³² and R ³³ are hydrogen atoms) and a group derived from dihydroxynaphthalene (a group wherein R ³⁴ is a hydroxyl group in formula (III-b)). One type is preferable.

Here, the “group derived from dihydroxybenzene” means a divalent group formed by removing two hydrogen atoms from the aromatic ring portion of dihydroxybenzene, and the position at which the hydrogen atom is removed is not particularly limited. Further, the “group derived from dihydroxynaphthalene” has the same meaning.

Further, from the viewpoint of productivity and fluidity of the epoxy resin composition, Ar ³¹ to Ar ³⁴ are more preferably each independently a group derived from dihydroxybenzene, and 1,2-dihydroxybenzene (catechol) More preferably, it is at least one selected from the group consisting of a group derived from the above and a group derived from 1,3-dihydroxybenzene (resorcinol). In particular, Ar ³¹ to Ar ³⁴ preferably include at least a group derived from resorcinol from the viewpoint of particularly improving thermal conductivity. Further, from the viewpoint of particularly improving thermal conductivity, the structural unit represented by n31 to n34 preferably contains a group derived from resorcinol.

When the compound having a partial structure represented by at least one selected from the group consisting of general formula (III-1) to general formula (III-4) includes a structural unit derived from resorcinol, it is derived from resorcinol The content of the structural unit containing the group is, in terms of elastic modulus, in the whole compound having the structure represented by at least one of the above general formulas (III-1) to (III-4) It is preferably 55% by mass or more, more preferably 80% by mass or more from the viewpoint of Tg and linear expansion coefficient, and further preferably 90% by mass or more from the viewpoint of thermal conductivity.

In the general formulas (III-1) to (III-4), the ratio of mx and nx (x is the same value of any one of 31, 32, 33, or 34) is mx / nx from the viewpoint of fluidity. = 20/1 to 1/5 is preferable, 20/1 to 5/1 is more preferable, and 20/1 to 10/1 is still more preferable. Further, the total value of mx and nx is preferably 20 or less, more preferably 15 or less, and still more preferably 10 or less from the viewpoint of fluidity. In addition, the lower limit of the total value of m and n is not particularly limited.

Mx and nx represent the number of structural units and indicate how much the corresponding structural unit is added in the molecule. Therefore, an integer value is shown for a single molecule. Note that mx and nx in (mx / nx) and (mx + nx) indicate rational numbers that are average values in the case of an assembly of a plurality of types of molecules.

The phenol novolak resin having a partial structure represented by at least one selected from the group consisting of the above general formulas (III-1) to (III-4) is particularly substituted or unsubstituted in Ar ³¹ to Ar ³⁴ In the case of at least one of dihydroxybenzene and substituted or unsubstituted dihydroxynaphthalene, it is easier to synthesize, and a curing agent having a low melting point can be obtained as compared with a novolak phenol resin or the like. Tend to be. Therefore, by including such a phenol resin as a curing agent, there are advantages such as easy manufacture and handling of the epoxy resin composition.
Whether or not the phenol novolac resin has a partial structure represented by any one of the general formulas (III-1) to (III-4) is determined by field desorption ionization mass spectrometry (FD-MS). The determination can be made based on whether or not the fragment component includes a component corresponding to the partial structure represented by any of the general formulas (II-1) to (II-4).

The molecular weight of the phenol novolac resin having a partial structure represented by at least one selected from the group consisting of general formula (III-1) to general formula (III-4) is not particularly limited. From the viewpoint of fluidity, the number average molecular weight (Mn) is preferably 2000 or less, more preferably 1500 or less, and even more preferably 350 to 1500. Further, the weight average molecular weight (Mw) is preferably 2000 or less, more preferably 1500 or less, and further preferably 400 to 1500. Mn and Mw are measured by a usual method using GPC (gel permeation chromatography).

The hydroxyl equivalent of the phenol novolac resin having a partial structure represented by at least one selected from the group consisting of general formula (III-1) to general formula (III-4) is not particularly limited. From the viewpoint of the crosslinking density involved in the heat resistance, the hydroxyl group equivalent is preferably 50 g / eq to 150 g / eq on average, more preferably 50 g / eq to 120 g / eq, and 55 g / eq to 120 g / eq. More preferably, it is eq. In addition, in this specification, a hydroxyl equivalent means the value measured based on JISK0070: 1992.

The phenol novolac resin may contain a monomer that is a phenol compound constituting the phenol novolac resin. The content of the monomer that is a phenol compound constituting the phenol novolac resin (hereinafter also referred to as “monomer content”) is not particularly limited. From the viewpoint of thermal conductivity and moldability, the monomer content in the phenol novolac resin is preferably 5% by mass to 80% by mass, more preferably 15% by mass to 60% by mass, and 20% by mass. More preferably, it is ˜50 mass%.

When the monomer content is 80% by mass or less, the amount of monomers that do not contribute to crosslinking decreases during the curing reaction, and the high molecular weight material that contributes to crosslinking occupies a large amount. It is formed and the thermal conductivity is improved. In addition, since the monomer content is 5% by mass or more, it is easy to flow during molding, so that the adhesion with the inorganic filler contained as necessary is further improved, and more excellent thermal conductivity and heat resistance. Tend to be achieved.

The content of the curing agent in the epoxy resin composition is not particularly limited. For example, when the curing agent is an amine curing agent, the ratio of the number of active hydrogen equivalents of the amine curing agent (amine equivalent number) to the number of epoxy groups equivalent of the epoxy monomer (amine equivalent number / epoxy equivalent number) Is preferably 0.5 to 2.0, more preferably 0.8 to 1.2. When the curing agent is a phenolic curing agent, the ratio of the phenolic hydroxyl group equivalent (phenolic hydroxyl group equivalent number) of the phenolic curing agent to the epoxy group equivalent number of the epoxy monomer (equivalent number of phenolic hydroxyl group / The number of equivalents of epoxy groups is preferably 0.5 to 2.0, and more preferably 0.8 to 1.2.

(Curing accelerator)
The epoxy resin composition may contain a curing accelerator. By using a curing agent and a curing accelerator in combination, it can be further sufficiently cured. The kind and content of the curing accelerator are not particularly limited, and an appropriate one can be selected from the viewpoint of reaction rate, reaction temperature, and storage property.

Specific examples include imidazole compounds, tertiary amine compounds, organic phosphine compounds, complexes of organic phosphine compounds and organic boron compounds, and the like. Among these, from the viewpoint of heat resistance, it is preferably at least one selected from the group consisting of an organic phosphine compound and a complex of an organic phosphine compound and an organic boron compound.

Specific examples of the organic phosphine compound include triphenylphosphine, diphenyl (p-tolyl) phosphine, tris (alkylphenyl) phosphine, tris (alkoxyphenyl) phosphine, tris (alkylalkoxyphenyl) phosphine, and tris (dialkylphenyl). ) Phosphine, tris (trialkylphenyl) phosphine, tris (tetraalkylphenyl) phosphine, tris (dialkoxyphenyl) phosphine, tris (trialkoxyphenyl) phosphine, tris (tetraalkoxyphenyl) phosphine, trialkylphosphine, dialkylarylphosphine And alkyldiarylphosphine.

Specific examples of the complex of an organic phosphine compound and an organic boron compound include tetraphenylphosphonium / tetraphenylborate, tetraphenylphosphonium / tetra-p-tolylborate, tetrabutylphosphonium / tetraphenylborate, and tetraphenylphosphonium. -N-butyltriphenylborate, butyltriphenylphosphonium / tetraphenylborate, methyltributylphosphonium / tetraphenylborate and the like.
One of these curing accelerators may be used alone, or two or more thereof may be used in combination.

When using two or more types of curing accelerators in combination, the mixing ratio should be determined without any particular restrictions depending on the characteristics (for example, how much flexibility is required) required for the semi-cured epoxy resin composition. Can do.

When the epoxy resin composition contains a curing accelerator, the content of the curing accelerator in the epoxy resin composition is not particularly limited. From the viewpoint of moldability, the content of the curing accelerator is preferably 0.5% by mass to 1.5% by mass of the total mass of the epoxy monomer and the curing agent, and 0.5% by mass to 1% by mass. More preferably, the content is 0.6% by mass to 1% by mass.

(Inorganic filler)
The epoxy resin composition may include an inorganic filler. By including the inorganic filler, the epoxy resin composition can achieve high thermal conductivity.
The inorganic filler may be non-conductive or conductive. Use of a non-conductive inorganic filler tends to suppress a decrease in insulation. Moreover, it exists in the tendency for thermal conductivity to improve more by using a conductive inorganic filler.

Specific examples of the non-conductive inorganic filler include aluminum oxide (alumina), magnesium oxide, aluminum nitride, boron nitride, silicon nitride, silica (silicon oxide), silicon oxide, aluminum hydroxide, and barium sulfate. . Examples of the conductive inorganic filler include gold, silver, nickel, and copper. Among these, from the viewpoint of thermal conductivity, the inorganic filler is preferably at least one selected from the group consisting of aluminum oxide (alumina), boron nitride, magnesium oxide, aluminum nitride, and silica (silicon oxide). More preferably, it is at least one selected from the group consisting of boron nitride and aluminum oxide (alumina).
These inorganic fillers may be used alone or in combination of two or more.

It is preferable to use a mixture of two or more inorganic fillers having different volume average particle diameters. As a result, the inorganic filler having a small particle diameter is packed in the voids of the inorganic filler having a large particle diameter, thereby filling the inorganic filler more densely than using only the inorganic filler having a single particle diameter. It becomes possible to exhibit higher thermal conductivity.
Specifically, when aluminum oxide is used as the inorganic filler, aluminum oxide having a volume average particle diameter of 16 μm to 20 μm is oxidized in the inorganic filler by 60 volume% to 75 volume% and volume average particle diameter of 2 μm to 4 μm. By mixing aluminum oxide with a volume average particle size of 0.3 μm to 0.5 μm in a ratio of 10 volume% to 20 volume%, it is possible to achieve closer packing. Become.
Further, when boron nitride and aluminum oxide are used in combination as the inorganic filler, boron nitride having a volume average particle diameter of 20 μm to 100 μm in the inorganic filler is oxidized by 60 volume% to 90 volume% and volume average particle diameter of 2 μm to 4 μm. By mixing aluminum oxide having a volume average particle diameter of 0.3 μm to 0.5 μm in a ratio of 5 volume% to 20 volume%, a higher heat conductivity can be achieved. . The volume average particle diameter of the inorganic filler is measured under normal conditions using a laser diffraction particle size distribution measuring apparatus.

The volume average particle diameter (D50) of the inorganic filler can be measured using a laser diffraction method. For example, the inorganic filler in the epoxy resin composition is extracted and measured using a laser diffraction / scattering particle size distribution analyzer (for example, trade name: LS230, manufactured by Beckman Coulter, Inc.). Specifically, using an organic solvent, nitric acid, aqua regia, etc., the inorganic filler component is extracted from the epoxy resin composition and sufficiently dispersed with an ultrasonic disperser, etc., and the weight cumulative particle size distribution curve of this dispersion liquid Measure.
The volume average particle diameter (D50) refers to the particle diameter at which accumulation is 50% from the small diameter side in the volume cumulative distribution curve obtained from the above measurement.

When the epoxy resin composition contains an inorganic filler, the content is not particularly limited. Among these, from the viewpoint of thermal conductivity, the content of the inorganic filler is preferably more than 50% by volume, more than 70% by volume, and 90% by volume when the total volume of the epoxy resin composition is 100% by volume. The following is more preferable. When the content of the inorganic filler exceeds 50% by volume, higher thermal conductivity can be achieved. On the other hand, when the content of the inorganic filler is 90% by volume or less, the flexibility of the epoxy resin composition and the insulating property tend to be suppressed.

(Silane coupling agent)
The epoxy resin composition may contain at least one silane coupling agent. The silane coupling agent has a role of forming a covalent bond between the surface of the inorganic filler and the surrounding resin (equivalent to a binder agent), an improvement in thermal conductivity, and prevents moisture penetration. It can be thought that it plays a role of improving sex.

The type of silane coupling agent is not particularly limited, and a commercially available product may be used. In consideration of reducing the compatibility between the specific epoxy monomer and the curing agent, and reducing heat conduction defects at the interface between the resin layer and the inorganic filler, in this embodiment, the terminal is an epoxy group, an amino group, a mercapto group. It is preferable to use a silane coupling agent having a ureido group and a hydroxyl group.

Specific examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane. 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltriethoxy Examples thereof include silane, 3-aminopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-ureidopropyltriethoxysilane. Also included are silane coupling agent oligomers (manufactured by Hitachi Chemical Techno Service Co., Ltd.) represented by trade name: SC-6000KS2. These silane coupling agents may be used alone or in combination of two or more.

(Other ingredients)
The epoxy resin composition may contain other components in addition to the above components, if necessary. Examples of other components include a solvent, an elastomer, 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 epoxy resin composition, and a commonly used organic solvent can be appropriately selected and used.

Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these examples.

The following materials were used as the first member and the second member in the laminates for evaluation in Examples and Comparative Examples.

First member A: an aluminum plate having a surface roughness (Rz) of 18 μm on the surface in contact with the resin layer (size: 40 mm × 40 mm × 3 mm)
Second member A: copper plate having a surface roughness (Rz) of 3 μm on the surface in contact with the resin layer (size: 40 mm × 40 mm × 3 mm)
First member B: an aluminum plate having a surface roughness (Rz) of 18 μm on the surface in contact with the resin layer (size: 160 mm × 160 mm × 3 mm)
Second member B: copper plate having a surface roughness (Rz) of 3 μm on the surface in contact with the resin layer (size: 160 mm × 160 mm × 3 mm)

The formation of the resin layer in the laminate for evaluation in Examples and Comparative Examples was performed using an epoxy resin composition. The material used for preparation of an epoxy resin composition and its abbreviation are shown below.

(Epoxy monomer A having mesogenic skeleton (monomer A))
[4- {4- (2,3-epoxypropoxy) phenyl} cyclohexyl = 4- (2,3-epoxypropoxy) benzoate, epoxy equivalent: 212 g / eq, by the method described in JP 2011-74366 A Manufacturing]

(Epoxy monomer B having mesogenic skeleton (monomer B))
YL6121H [Biphenyl type epoxy monomer, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: 172 g / eq]

(Inorganic filler)
AA-3 [Alumina particles, manufactured by Sumitomo Chemical Co., Ltd., D50: 3 μm]
AA-04 [Alumina particles, manufactured by Sumitomo Chemical Co., Ltd., D50: 0.40 μm]
HP-40 [boron nitride particles, manufactured by Mizushima Alloy Iron Co., Ltd., D50: 40 μm]

(Curing agent)
CRN [catechol resorcinol novolak (mass-based charge ratio: catechol / resorcinol = 5/95) resin, containing 50% by mass of cyclohexanone]

<Synthesis method of CRN>
A 3 L separable flask equipped with a stirrer, a cooler and a thermometer was charged with 627 g of resorcinol, 33 g of catechol, 316.2 g of a 37 mass% formaldehyde aqueous solution, 15 g of oxalic acid, and 300 g of water, and heated while heating in an oil bath. The temperature was raised to ° C. The mixture was refluxed at around 104 ° C., and the reaction was continued at the reflux temperature for 4 hours. 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. After the reaction, concentration was performed under reduced pressure for 20 minutes to remove water and the like in the system to obtain the target phenol novolac resin CRN.
Further, when the structure of the obtained CRN was confirmed by FD-MS (field desorption ionization mass spectrometry), all the partial structures represented by the general formulas (III-1) to (III-4) were confirmed. Existence was confirmed.

Note that, under the above reaction conditions, a compound having a partial structure represented by the general formula (III-1) is formed first, and this is further subjected to a dehydration reaction, whereby the general formulas (III-2) to (III-4) It is considered that a compound having a partial structure represented by at least one of

About the obtained CRN, Mn (number average molecular weight) and Mw (weight average molecular weight) were measured as follows.
Mn and Mw were measured using a high performance liquid chromatography (manufactured by Hitachi, Ltd., trade name: L6000) and a data analyzer (manufactured by Shimadzu Corporation, trade name: C-R4A). As analytical GPC columns, G2000HXL and G3000HXL (trade names) manufactured by Tosoh Corporation were used. The sample concentration was 0.2% by mass, tetrahydrofuran was used as the mobile phase, and the measurement was performed at a flow rate of 1.0 mL / min. A calibration curve was prepared using a polystyrene standard sample, and Mn and Mw were calculated using polystyrene conversion values.

With respect to the obtained CRN, the hydroxyl equivalent was measured as follows.
The hydroxyl equivalent was measured by acetyl chloride-potassium hydroxide titration method. The determination of the titration end point was performed by potentiometric titration instead of the coloring method using an indicator because the solution color was dark. Specifically, the hydroxyl group of the measurement resin is acetylated in a pyridine solution, the excess reagent is decomposed with water, and the resulting acetic acid is titrated with a potassium hydroxide / methanol solution.

The obtained CRN is a mixture of compounds having a partial structure represented by at least one of the general formulas (III-1) to (III-4), and Ar is represented by the general formula (III-a ) In which R ³¹ is a hydroxyl group, and R ³² and R ³³ are hydrogen atoms, a group derived from 1,2-dihydroxybenzene (catechol) and a group derived from 1,3-dihydroxybenzene (resorcinol), It was a novolak resin containing a curing agent (hydroxyl equivalent 62 g / eq, number average molecular weight 422, weight average molecular weight 564) containing 35% by mass of a monomer component (resorcinol) as a molecular diluent.

(Curing accelerator)
・ TPP: Triphenylphosphine [Wako Pure Chemical Industries, Ltd., trade name]

(Additive)
KBM-573: 3-phenylaminopropyltrimethoxysilane [silane coupling agent, manufactured by Shin-Etsu Chemical Co., Ltd., trade name]

(solvent)
CHN: cyclohexanone

<Example 1>
(Preparation of epoxy resin composition)
As an epoxy monomer having a mesogenic skeleton, monomer A and monomer B were mixed so that the epoxy equivalent was 8: 2, and an epoxy monomer mixture was obtained.

8.19% by mass of the epoxy monomer mixture, 4.80% by mass of CRN as a curing agent, 0.09% by mass of TPP as a curing accelerator, and 39.95% by mass of HP-40 as an inorganic filler , 9.03 wt% AA-3, 9.03 wt% AA-04, 0.06 wt% KBM-573 as additive, and 28.85 wt% CHN as solvent. Then, a varnish-like epoxy resin composition was prepared.

The density of boron nitride (HP-40) is 2.20 g / cm ³ , the density of alumina (AA-3 and AA-04) is 3.98 g / cm ³ , and epoxy monomers (monomer A and monomer B) and curing agent When the density of the mixture with (CRN) was 1.20 g / cm ^{3 and} the ratio of the inorganic filler to the total volume of the total solid content of the epoxy resin composition was calculated, it was 72% by volume.

(Preparation of evaluation laminate)
The first member A is prepared such that the epoxy resin composition is dried using a dispenser (trade name: SHOTMASTER300DS-S, manufactured by Musashi Engineering Co., Ltd.) so that the resin layer has a size of 40 mm × 40 mm and a thickness of 400 μm. It was applied on the surface in contact with the resin layer. Thereafter, it was allowed to stand at room temperature (20 ° C. to 30 ° C.) for 5 minutes using an oven (trade name: SPHH-201 manufactured by ESPEC), and further dried at 130 ° C. for 5 minutes to form a resin layer. Subsequently, hot pressing (press temperature: 150 ° C., degree of vacuum: 1 kPa, press pressure: 15 MPa, pressurization time: 1 minute) was performed by a vacuum press, and the resin layer was brought into a B-stage state. Next, the second member A is sandwiched so that the surface in contact with the resin layer faces the resin layer, and is vacuum thermocompression-bonded by a vacuum press (press temperature: 180 ° C., vacuum degree: 1 kPa, press pressure: 15 MPa, pressurization time) : 6 minutes). Then, the epoxy resin cured product laminate 1 was obtained by heating at 150 ° C. for 2 hours and at 210 ° C. for 4 hours under atmospheric pressure conditions.

<Examples 2 to 4>
Epoxy resin compositions of Examples 2 to 4 were prepared in the same manner as in Example 1 except that the amount of the solvent (CHN) was changed. Subsequently, the laminated body for evaluation was produced like Example 1 except having used each epoxy resin composition.

<Example 5>
In the same manner as in Example 1, a resin layer was formed on the surface of the first member A in contact with the resin layer using the epoxy resin composition used in Example 1, and a B stage was obtained. Similarly, a resin layer was formed on the surface of the second member A in contact with the resin layer using the epoxy resin composition used in Example 1, and a B-stage state was obtained.
Next, in a state where the resin layer of the first member A and the resin layer of the second member A are stacked so as to face each other, vacuum thermocompression bonding (press temperature: 180 ° C., degree of vacuum: 1 kPa, press pressure: 15 MPa, pressurization time: 6 minutes). Thereafter, heating was performed at 150 ° C. for 2 hours and 210 ° C. for 4 hours under atmospheric pressure conditions, followed by cooling to prepare a laminate for evaluation.

<Comparative Example 1>
Using the epoxy resin composition used in Example 1 with a dispenser (trade name: SHOTMASTER300DS-S, manufactured by Musashi Engineering Co., Ltd.), the size of the resin layer after drying is 160 mm × 160 mm and the thickness is 400 μm. The first member B was coated on the surface in contact with the resin layer. Thereafter, the resin layer was formed by drying at room temperature (20 ° C. to 30 ° C.) for 5 minutes and further at 130 ° C. for 5 minutes. Subsequently, hot pressing (press temperature: 150 ° C., degree of vacuum: 1 kPa, press pressure: 15 MPa, pressurization time: 1 minute) was performed by a vacuum press, and the resin layer was brought into a B-stage state. The 1st member in which the resin layer was formed was cut | disconnected using the table saw from the resin layer side so that it might become a magnitude | size of about 40 mm x 40 mm. Next, the second member A was disposed on the resin layer. In this state, vacuum thermocompression bonding (press temperature: 180 ° C., degree of vacuum: 1 kPa, press pressure: 15 MPa, pressurization time: 6 minutes) was performed with a vacuum press. Thereafter, heating was performed at 150 ° C. for 2 hours and 210 ° C. for 4 hours under atmospheric pressure conditions, followed by cooling to prepare a laminate for evaluation.

<Comparative Example 2>
First, the epoxy resin composition used in Example 1 was first dried so as to have a size of 160 mm × 160 mm and a thickness of 200 μm after drying using a dispenser (trade name: SHOTMASTER300DS-S manufactured by Musashi Engineering Co., Ltd.). It applied on the surface which contacts the resin layer of member B. Thereafter, the resin layer was formed by drying at room temperature (20 ° C. to 30 ° C.) for 5 minutes and further at 130 ° C. for 5 minutes. Similarly, a resin layer was also formed on the surface of the second member B in contact with the resin layer. The 1st member B and the 2nd member B in which the resin layer was formed were cut | disconnected using the table saw from the resin layer side so that it might become a magnitude | size of 40 mm x 40 mm, respectively. Next, the resin layer of the first member B and the resin layer of the second member B are overlapped so as to face each other, and in this state, vacuum thermocompression bonding (press temperature: 180 ° C., vacuum degree: 1 kPa, press pressure: 15 MPa, pressurization time: 6 minutes). Thereafter, heating was performed at 150 ° C. for 2 hours and 210 ° C. for 4 hours under atmospheric pressure conditions, followed by cooling to prepare a laminate for evaluation.

(Presence or absence of resin waste and resin cracks)
After the resin layer was formed on the first member A or the first member B and vacuum-pressed, the presence or absence of resin debris adhesion and resin cracks were visually examined. The results are shown in Table 1.

(Presence / absence of cutting waste from the parts)
The produced laminated body was observed visually and the presence or absence of the cutting waste of a member was investigated. The results are shown in Table 1.

(Measurement of viscosity)
25 ° C. of the epoxy resin composition used in the production of the ^laminate, and a viscosity A at ^{5min -1 (rpm), 25 ℃} , the viscosity B at ^{0.5 min} -1 (rpm), E-type viscometer (Toki Measurement was performed using a trade name: TV-33) manufactured by Sangyo Co., Ltd. Further, a thixotropic index (B / A) was calculated from the obtained value. The results are shown in Table 1.

(Evaluation of applicability)
The applicability of the epoxy resin composition used for the production of the laminate was evaluated according to the following criteria.
“Pass”: When fading is not seen on the coated surface of the epoxy resin composition immediately after coating “Fail”: When fading is seen on the coated surface of the epoxy resin composition immediately after coating If the epoxy resin composition is clogged with a dispenser and cannot be applied

(Evaluation of shape retention)
The shape retention of the epoxy resin composition was evaluated according to the following criteria.
“Pass”: When 1 mL of the epoxy resin composition is dropped onto the glossy surface of the copper foil from 2 cm above the copper foil and the wetting spread is less than 30 mm in radius. “Fail”: The glossy surface of the copper foil When 1 mL of epoxy resin composition is dropped from 2 cm above the copper foil and the wetting spread is 30 mm or more in radius

(Measurement of breakdown voltage)
After connecting the first member of the produced laminate to the plus electrode and the second member to the minus electrode, the laminate was placed in Fluorinert and the dielectric breakdown voltage was measured. The measurement condition is that the measurement start voltage is 500 (V), the voltage is increased stepwise by 500 (V) and held for 30 seconds, and the voltage when the current value exceeds 0.01 (mA) is measured. The dielectric breakdown voltage was used. The above measurement was carried out using 10 laminates produced under the same conditions, and Table 1 shows the minimum values of the obtained data.

(Judgment)
When there is no resin waste, resin cracks and cutting waste of members, the evaluation of applicability and shape retention is “pass”, and the minimum value of dielectric breakdown voltage is 6 (kV) or more, “pass”, Otherwise, it was determined as “Fail”. The results are shown in Table 1.

From the results shown in Table 1, in Examples 1 to 5 using the first member A separated in advance, a laminate having no high resin breakdown voltage and no resin waste was obtained.
On the other hand, in the comparative example using the 1st member B which has not been separated into pieces beforehand, the generation | occurence | production of the resin waste etc. accompanying the cutting process of a resin layer and a member was seen, and the dielectric breakdown voltage was also lower than the Example.

DESCRIPTION OF SYMBOLS 1 ... 1st member 2 ...

Resin layer

3, 4 ... Hot plate 5 ...

2nd member

6, 7 ... Hot plate 10 ... Burr 11 ... Resin crack 12 ... Resin cutting waste 13 ... First member cutting waste

The entire disclosure of Japanese Patent Application No. 2016-111374 is incorporated herein by reference. All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated to be incorporated by reference, Incorporated herein by reference.

Claims

A laminate comprising: a resin layer forming step of forming a resin layer on the separated first member; and a member arranging step of arranging the separated second member on the resin layer. Production method.
The resin layer is formed by applying a resin composition to the first member, and the resin composition has a thixotropic index of 3 or more at a temperature when applying the resin composition to the first member. The manufacturing method of the laminated body of Claim 1 which exists.
The method for producing a laminate according to claim 1, wherein the resin layer includes an epoxy resin.
The resin layer according to any one of claims 1 to 3, wherein the resin layer is formed using an epoxy resin composition containing two or more types of epoxy monomers having a mesogenic skeleton and a curing agent. A manufacturing method of a layered product.
The method for producing a laminate according to claim 4, wherein the two or more epoxy monomers having the mesogenic skeleton include a compound represented by the following general formula (I).

[In general formula (I), R 1 to R 4 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. ]