WO2012172972A1

WO2012172972A1 - Cross-linked polyimide resin and method for producing same, adhesive resin composition and cured product thereof, cover lay film, circuit board, heat-conductive substrate, and heat-conductive polyimide film

Info

Publication number: WO2012172972A1
Application number: PCT/JP2012/063859
Authority: WO
Inventors: 亮森; 芳樹須藤; 王　宏遠
Original assignee: 新日鉄住金化学株式会社
Priority date: 2011-06-14
Filing date: 2012-05-30
Publication date: 2012-12-20
Also published as: TWI546322B; KR20140021001A; TW201305248A; KR101757023B1; CN103649174B; CN103649174A

Abstract

Disclosed is a cross-linked polyimide resin produced by reacting (A) a polyimide siloxane having a ketone group with (B) an amino compound having at least two primary amino groups as functional groups. Each of the amino groups in the amino compound, i.e., the component (B), is reacted with at least a part of the ketone group in the polyimide siloxane, i.e., the component (A), to form a C=N bond. Thus, the cross-linked polyimide resin has such a structure that the polyimide siloxane is crosslinked through the amino compound. When a hydrogen-bond-forming group is contained in the component (A), the formation of the C=N bond can be promoted.

Description

Crosslinked polyimide resin, production method thereof, adhesive resin composition, cured product thereof, coverlay film, circuit board, heat conductive substrate, and heat conductive polyimide film

The present invention relates to a crosslinked polyimide resin useful as an adhesive in a circuit board such as a flexible printed wiring board, a production method thereof, and use thereof.

In recent years, with the progress of miniaturization, weight reduction, and space saving of electronic devices, flexible printed wiring boards (FPCs) that are thin, light, flexible, and have excellent durability even after repeated bending are used. The demand for Circuits) is increasing. FPC can be mounted three-dimensionally and densely in a limited space. For example, it can be used for wiring of movable parts of electronic devices such as HDDs, DVDs, mobile phones, and parts such as cables and connectors. It is expanding.

For FPC, a coverlay film is used for the purpose of protecting the wiring part. The coverlay film is formed by laminating a coverlay film material made of a synthetic resin such as a polyimide resin and an adhesive layer. In manufacturing an FPC, a coverlay film material is attached to a circuit board through an adhesive layer by using a method such as hot pressing. The adhesive layer is required to have high adhesion to both the circuit wiring pattern such as copper wiring and the film material for coverlay. As an adhesive for such a coverlay film, it can be processed under relatively low temperature thermocompression bonding conditions, and it has excellent heat resistance and other characteristics, and it can be used as a mixed resin of polyimide resin and epoxy resin having a siloxane unit. In addition, an adhesive resin composition for printed circuit boards has been proposed which comprises one or more plasticizers selected from phosphoric acid esters, phthalic acid esters, polyesters and fatty acid esters (for example, Japanese (Kaihei 10-212468).

On the other hand, bis (3,4-dicarboxyphenyl) ether dianhydride and a specific structure are used for the purpose of improving the low-temperature sticking property, low moisture absorption, heat adhesion, and PCT resistance of polyimide resin used for adhesive films. A method for producing a polyimide resin in which another acid anhydride and / or another diamine is reacted after reacting with another siloxane diamine has been proposed (for example, Japanese Patent Application Laid-Open No. 2006-117945). In addition, in order to safely and stably produce a high molecular weight polyimide resin having a silicone structure in the main chain, silicone-based diamine and silicone-based acid dianhydride are mixed in a specific molar ratio range, and heat dehydration condensation is performed. There is also proposed a method for producing a polyimide resin in which an aromatic diamine is added to a reaction solution at a predetermined molar ratio and reacted after the reaction until no longer increases, and the molecular weight is controlled (for example, Japanese Patent Application Laid-Open No. 2004-2004). 359874).

Since the FPC processing includes a soldering process almost essential, the adhesive used for the coverlay film is required to have high solder heat resistance. In this regard, polyimide resin with relatively excellent heat resistance is a material suitable as an adhesive for the coverlay film, but if the solder heat resistance can be further improved, the function as an adhesive for the coverlay film will be improved. Can be increased.

In addition, in-vehicle electronic devices for automobiles using FPC are repeatedly placed in a high temperature environment of about 150 ° C., the adhesive strength between the FPC coverlay film and the wiring is lowered over a long period of use, and the wiring protection function is provided. There has been a problem of a significant drop. With the expansion of FPC applications, it is expected that the number of scenes where FPC is used not only in in-vehicle electronic devices but also in severe temperature environments will continue to increase. For this reason, in an FPC used in a high temperature environment, it is strongly required to take measures against a decrease in the adhesive strength of the coverlay film.

Accordingly, an object of the present invention is to form a cross-linked polyimide capable of forming a cross-linked structure capable of exhibiting moisture-resistant solder heat resistance in a short time and capable of forming an adhesive layer that does not reduce adhesive strength even in a use environment that is repeatedly exposed to high temperatures. It is to provide a resin.

The inventors of the present invention have completed the present invention as a result of intensive studies to solve the above problems. In a preferred embodiment of the present invention, by introducing a functional group capable of hydrogen bonding (hereinafter referred to as “hydrogen bond-forming group”) into the polyimidesiloxane after imidization, the main chains of the polyimidesiloxane are interlinked. As a result, a hydrogen bond is formed and the ketone group of the adjacent polyimide siloxane chain is brought into a close state, so that the formation of a cross-link between the ketone group of the polyimide siloxane and the amino compound is promoted.

The crosslinked polyimide resin of the present invention comprises the following components (A) and (B),
(A) a polyimidesiloxane having a ketone group, and
(B) an amino compound having at least two primary amino groups as functional groups,
A cross-linked polyimide resin obtained by reacting
The amino group of the amino compound of the component (B) reacts with at least a part of the ketone group in the polyimide siloxane of the component (A) to form a C═N bond, so that the polyimide siloxane is formed by the amino compound. It has a cross-linked structure.

In the crosslinked polyimide resin of the present invention, the polyimidesiloxane may be a polyimidesiloxane having structural units represented by the following general formulas (1) and (2). In this case, it is preferable that the molar ratio m of the structural unit is in the range of 0.75 to 1.0, and n is in the range of 0 to 0.25.

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic acid anhydride, R ₁ is a divalent diaminosiloxane residue derived from diaminosiloxane, and R ₂ is derived from a diamine compound. Each represents a divalent diamine residue, and Ar and / or R ₂ contains a ketone group and a hydrogen bond-forming group, m and n represent the molar ratio of each constituent unit, and m is 0.35 to 1 In the range of 0, n is in the range of 0 to 0.65]

Further, in the crosslinked polyimide resin of the present invention, the polyimidesiloxane may be a polyimidesiloxane having structural units represented by the following general formulas (1) and (2). In this case, it is preferable that the molar ratio m of the structural unit is in the range of 0.75 or more and less than 1.0, and n is in the range of more than 0 and 0.25 or less.

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic acid anhydride, R ₁ is a divalent diaminosiloxane residue derived from diaminosiloxane, and R ₂ is derived from a diamine compound. Each represents a divalent diamine residue, Ar contains a ketone group, R ₂ contains a hydrogen bond-forming group, m and n represent the molar ratio of each constituent unit, and m is 0.35 or more and 1 Within the range of less than 0, n is in the range of more than 0 and not more than 0.65]

In the crosslinked polyimide resin of the present invention, the hydrogen bond-forming group in the polyimidesiloxane may be —NHCO—.

The crosslinked polyimide resin of the present invention may be one in which the polyimide siloxane is synthesized using a dihydrazide compound as a raw material.

In the crosslinked polyimide resin of the present invention, the amino compound may be a dihydrazide compound.

In the crosslinked polyimide resin of the present invention, the plate-like inorganic filler having an average particle size in the range of 2 to 25 μm is further added in an amount of 5 to 200 wt. It may be contained within the range of parts.

The adhesive resin composition of the present invention comprises the following components (A) and (B):
(A) a polyimidesiloxane having a weight average molecular weight of 20,000 to 150,000 having a ketone group and a hydrogen bond-forming group, and (B) an amino compound having at least two primary amino groups as functional groups,
Including
The component (B) is contained so that the total amount of the primary amino group is within the range of 0.004 mol to 1.5 mol with respect to 1 mol of the ketone group in the component (A). .

In the adhesive resin composition of the present invention, the component (A) may be a polyimide siloxane having structural units represented by the following general formulas (1) and (2). In this case, it is preferable that the molar ratio m of the structural unit is in the range of 0.75 to 1.0, and n is in the range of 0 to 0.25.

In the adhesive resin composition of the present invention, the component (A) may be a polyimide siloxane having structural units represented by the following general formulas (1) and (2). In this case, it is preferable that the molar ratio m of the structural unit is in the range of 0.75 or more and less than 1.0, and n is in the range of more than 0 and 0.25 or less.

In the adhesive resin composition of the present invention, the hydrogen bond forming group in the component (A) may be —NHCO—.

In the adhesive resin composition of the present invention, the component (A) may be synthesized using a dihydrazide compound as a raw material.

In the adhesive resin composition of the present invention, the component (B) may be a dihydrazide compound.

The adhesive resin composition of the present invention further comprises (C) a plate-like inorganic filler having an average particle size in the range of 2 to 25 μm with respect to a total of 100 parts by weight of the components (A) and (B). It may contain 5 to 200 parts by weight.

The cured product of the present invention is obtained by curing the adhesive resin composition described above.

The coverlay film of the present invention is a coverlay film in which an adhesive layer and a film material layer for coverlay are laminated,
The adhesive layer is formed using the adhesive resin composition according to any one of the above.

The circuit board of the present invention includes a base material, a wiring layer formed on the base material, and the cover lay film covering the wiring layer.

The method for producing a crosslinked polyimide resin of the present invention comprises mixing an acid anhydride component having a ketone group, a diamine compound having a hydrogen bond-forming group and a diamine component containing diaminosiloxane, and imidizing by heating. Forming a polyimidesiloxane having a ketone group and a hydrogen bond-forming group;
Forming hydrogen bonds between adjacent main chains in the polyimidesiloxane; and
At least a part of the ketone group of the polyimide siloxane is reacted with an amino group of an amino compound having at least two primary amino groups as a functional group to form a C = N bond, and the polyimide siloxane is crosslinked with the amino compound. The process of
It has.

The thermally conductive substrate of the present invention is a thermally conductive substrate having a metal layer on one or both sides of an insulating layer having at least one filler-containing polyimide resin layer in which a thermally conductive filler is dispersed in a polyimide resin. The filler-containing polyimide resin layer has a heat conductive filler content of 5 to 80 wt% (% by weight; the same applies hereinafter), and the polyimide resin in the filler-containing polyimide resin layer has the following general formula: The ketone group in the polyimidesiloxane having the structural units represented by (1) and (2) reacts with an amino group of an amino compound having at least two primary amino groups as functional groups to form a C═N bond. By forming, the polyimide siloxane is a crosslinked polyimide resin having a structure crosslinked by the amino compound. And wherein the Rukoto.

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic anhydride, R ₁ is a divalent diaminosiloxane residue derived from diaminosiloxane, R ₂ is an aromatic diamine and / or Each represents a divalent diamine residue derived from an aliphatic diamine, Ar and / or R ₂ contains a ketone group, m and n represent the molar ratio of each constituent unit, and m is 0.4 In the range of -1.0 and n is in the range of 0-0.6]

Moreover, the thermally conductive polyimide film of the present invention is a thermally conductive polyimide film comprising a filler-containing polyimide resin layer in which a thermally conductive filler is dispersed in a polyimide resin,
The content of the heat conductive filler in the filler-containing polyimide resin layer is in the range of 5 to 80 wt%, and the polyimide resin in the filler-containing polyimide resin layer is represented by the following general formulas (1) and (2). The polyimide siloxane having a structural unit reacts with the amino group of an amino compound having at least two primary amino groups as a functional group to form a C═N bond with the ketone group in the polyimide siloxane having a structural unit. It is a crosslinked polyimide resin having a structure crosslinked by the amino compound.

The crosslinked polyimide resin of the present invention has a structure in which an amino group of an amino compound reacts with at least a part of a ketone group in polyimidesiloxane to form a C═N bond, and at least a part of the polyimidesiloxane is crosslinked with an amino compound. For this reason, while being excellent in solder heat resistance, the adhesive bond layer which does not reduce the adhesive force with a metal wiring layer can be formed even if it is repeatedly placed in a high temperature environment. Therefore, the peel strength of the coverlay film formed with the adhesive layer using the crosslinked polyimide resin of the present invention can be increased, and the reliability of the circuit board using the coverlay film can be improved.

In addition, in a preferred embodiment of the crosslinked polyimide resin of the present invention, polyimide siloxane having a ketone group and a hydrogen bond-forming group is used, so that not only the curing by crosslinking formation is complete, but also excellent moisture-resistant soldering heat resistance at the intermediate stage. Can be expressed. Therefore, it is possible to achieve both excellent adhesion and solder heat resistance, and it is useful as an adhesive for coverlay films and the like.

The method for producing a crosslinked polyimide resin of the present invention uses a polyimide siloxane having a ketone group and a hydrogen bond-forming group, so that even in the state of the composition before heating, the adjacent polyimide siloxane main chains are close to each other by hydrogen bonding. Become. Therefore, the ketone groups of polyimide siloxane come close to each other, and the cross-linking with the amino group of the amino compound can be promoted. Accordingly, it is possible to form a cross-link in a short time, and it is possible to shorten the heat treatment time required for curing.

4 is a graph showing the results of rheometer evaluation of samples in Test Example 1. 10 is a graph showing the results of rheometer evaluation of samples in Test Example 2.

[Crosslinked polyimide resin]
The crosslinked polyimide resin of the present invention comprises the following components (A) and (B),
(A) a polyimidesiloxane having a ketone group, and
(B) an amino compound having at least two primary amino groups as functional groups,
Is a crosslinked polyimide resin obtained by reacting In the crosslinked polyimide resin of the present invention, the amino group of the amino compound (B) reacts with at least a part of the ketone group in the polyimide siloxane (A) to form a C = N bond. Thus, the polyimide siloxane has a structure crosslinked with the amino compound.

In a preferred embodiment of the crosslinked polyimide resin of the present invention, the group Ar in the general formulas (1) and (2) is a tetravalent aromatic group derived from an aromatic tetracarboxylic acid anhydride, and the group R ₁ is It is a divalent diaminosiloxane residue derived from diaminosiloxane, and the group R ₂ is a divalent diamine residue derived from a diamine compound. In addition, Ar and / or R ₂ contains a ketone group and a hydrogen bond-forming group, and m indicating the molar ratio of the constituent units is in the range of 0.35 to 1.0, preferably 0.75 to 1. In the range of 0, n is in the range of 0 to 0.65, preferably in the range of 0 to 0.25. In a more preferred embodiment of the crosslinked polyimide resin of the present invention, the group Ar in the general formulas (1) and (2) may contain a ketone group, and the group R ₂ may contain a hydrogen bond forming group. In this case, m indicating the molar ratio of the constituent units is in the range of 0.35 or more and less than 1.0, more preferably in the range of 0.75 or more and less than 1.0, and most preferably 0.75 or more and 0.99. Within the following range. Further, n indicating the molar ratio of the constituent units is in the range of more than 0 to 0.65 or less, more preferably in the range of more than 0 to 0.25 or less, most preferably in the range of 0.01 to 0.25. Is within.

In the crosslinked polyimide resin of the present invention, it is only necessary that the amino group of the amino compound of the component (B) reacts with at least a part of the ketone group in the polyimide siloxane of the component (A) to form a C = N bond. . The crosslinking formation rate (degree of curing) of the crosslinked polyimide resin does not have to be a state in which the curing of the polyimide resin by the crosslinking formation is completed, and may be any level that can ensure practically sufficient moisture-resistant soldering heat resistance. Whether the crosslinked polyimide resin has practically sufficient moisture-resistant soldering heat resistance can be determined using viscosity as an index, as will be described later.

[Polyimide siloxane]
The component (A) includes, for example, a polyimide siloxane having structural units represented by the general formulas (1) and (2), the group Ar and / or the group R ₂ , preferably a ketone group in the group Ar, This ketone group is involved in the reaction with the amino compound. In the structural units represented by the general formulas (1) and (2), examples of the aromatic tetracarboxylic acid for forming the group Ar containing a ketone group include 3,3 represented by the following formula (3): Mention may be made of '4,4'-benzophenone tetracarboxylic dianhydride (BTDA).

In addition, in the structural units represented by the general formulas (1) and (2), examples of the aromatic tetracarboxylic acid used as a raw material for forming the group Ar include, in addition to those having the ketone group, for example, 3, 3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-diphenylsulfone tetracarboxylic dianhydride (DSDA), pyromellitic dianhydride (PMDA) Etc. can be used. These can be used alone or in combination of two or more.

In the polyimidesiloxane having the structural units represented by the general formulas (1) and (2), examples of the “hydrogen bond forming group” include —NHCO—. By including such a hydrogen bond-forming group, a hydrogen bond is generated between adjacent polyimide siloxane chains, and the ketone groups that are the reaction points of the crosslinking reaction with the amino compound can be brought close to each other. The reaction is accelerated and the heating time until sufficient moisture-resistant soldering heat resistance is generated can be shortened. The hydrogen bond forming group may be contained in either one of the general formulas (1) and (2), or may be contained in both. In addition, the hydrogen bond-forming group may be contained in either the acid anhydride component represented by the group Ar or the diamine component represented by the group R ₁ or R _2. It is preferably contained in the group R ₂ in 2). The molar ratio of hydrogen bond-forming groups to all diamines is in the range of more than 0 and less than or equal to 1.3, more preferably more than 0 and less than 0 in order to efficiently form hydrogen bonds between the main chains of adjacent polyimidesiloxanes. .5 or less, and most preferably 0.02 or more and 0.5 or less.

In addition, examples of the group R ₁ in the structural unit represented by the general formula (1) include a diaminosiloxane residue derived from a diaminosiloxane represented by the following formula (4).

[Wherein R ₃ and R ₄ each represents a divalent organic group which may contain an oxygen atom, R ₅ to R ₈ each represents a hydrocarbon group having 1 to 6 carbon atoms, The average number of repetitions m ₁ is 1 to 20]

In particular, as the group R ₁ , R ₃ and R ₄ in the formula (4) are each a divalent hydrocarbon group for imparting polyimide solubility, and R ₅ to R ₈ each have 1 to 6 having a mean repeating number of m ₁ of 5 to 15 is preferable.

The diaminosiloxane residue is a group having a siloxane bond (Si—O—Si) obtained by removing an amino group from diaminosiloxane. By increasing the ratio of the siloxane bond, a plasticizer can be added. Sufficient flexibility is imparted to the adhesive layer, and warping of the coverlay film can be suppressed. Moreover, since many plastic groups are contained in the plasticizer, as an advantage of not containing the plasticizer, an adhesive using polyimidesiloxane having the structural units represented by the general formulas (1) and (2) It is mentioned that the amount of polar groups contained in the resin composition can be suppressed. For this reason, in this Embodiment, the value of m in Formula (1) shall be 0.35 or more, Preferably it is 0.75 or more. If the value of m is less than 0.35, the warp suppressing effect cannot be sufficiently obtained. In addition, it is considered that increasing the siloxane bond also has an effect of reducing curing shrinkage due to a decrease in the imide bond site of polyimidesiloxane.

Thus, by introducing a siloxane skeleton into the polyimide using the diaminosiloxane represented by the above general formula (4), the resulting polyimidesiloxane is given fluidity at the time of thermocompression bonding, and on the printed circuit wiring. Fillability can be improved. As specific examples of the diaminosiloxane represented by the general formula (4), diaminosiloxanes represented by the following formulas (5) to (9) are preferable, and among these, the formula (5) or the formula (6) The aliphatic diaminosiloxane represented is more preferred. These diaminosiloxanes can be blended in combination of two or more. Moreover, when mix | blending in combination of 2 or more types of diaminosiloxane, 90 weight part or more of aliphatic diaminosiloxane represented by Formula (5) or Formula (6) is mix | blended with respect to 100 weight part of all the diaminosiloxanes. Is preferred. In the formulas (4) to (9), the average repeat number m ₁ is in the range of 1 to 20, and preferably in the range of 5 to 15. When m ₁ is smaller than _1, the filling property when an adhesive is used is lowered, and when it exceeds 20, the adhesive property is lowered.

In the structural unit represented by the general formula (2), examples of the group R ₂ containing a ketone group (a divalent diamine residue derived from a diamine compound) include those represented by the following formulas (10) and (11). And aromatic diamines. These can be used alone or in combination of two or more.

[Wherein R ₉ independently represents a monovalent hydrocarbon group or alkoxy group having 1 to 6 carbon atoms, X represents CO, and n ₁ independently represents an integer of 0 to 4]

Examples of the aromatic diamine for forming the group R ₂ represented by the above formulas (10) and (11) include 4,4′-bis (3-aminophenoxy) benzophenone (BABP), 1,3- And bis [4- (3-aminophenoxy) benzoyl] benzene (BABB).

In the structural unit represented by the general formula (2), as the diamine compound that is a raw material for forming the group R ₂ having a hydrogen bond-forming group, for example, when the hydrogen bond-forming group is a —NHCO— group Can include dihydrazide compounds. Specific examples of the dihydrazide compound include dodecanedioic acid dihydrazide and adipic acid dihydrazide, which are aliphatic dihydrazides, and isophthalic acid dihydrazide, which is an aromatic dihydrazide. Among these, dodecanedioic acid dihydrazide and adipic acid dihydrazide which are aliphatic dihydrazides are preferable.

In addition, in the structural unit represented by the general formula (2), as another diamine compound that is a raw material for forming the group R ₂ , for example, 2,2-bis (4-aminophenoxyphenyl) propane (BAPP ) 2,2′-divinyl-4,4′-diaminobiphenyl (VAB), 2,2′-dimethyl-4,4′-diaminobiphenyl (m-TB), 2,2′-diethyl-4,4 '-Diaminobiphenyl, 2,2', 6,6'-tetramethyl-4,4'-diaminobiphenyl, 2,2'-diphenyl-4,4'-diaminobiphenyl, 9,9-bis (4-amino And aromatic diamines such as phenyl) fluorene. These aromatic diamines can be used alone or in combination of two or more.

As for the above-mentioned acid anhydride and diamine, which are the raw materials for polyimide siloxane, only one kind of each may be used, or two or more kinds may be used in combination. In addition, acid anhydrides and diamines other than those described above can be used in combination.

[Synthesis of polyimide siloxane]
(A) The polyimidesiloxane of a component can be manufactured by making the said aromatic tetracarboxylic anhydride, diaminosiloxane, and diamine react in a solvent, producing | generating the polyamic acid which is precursor resin, and carrying out ring closure by heating. For example, it is a polyimide precursor by dissolving an acid anhydride component and a diamine component in an organic solvent in approximately equimolar amounts and stirring them at a temperature in the range of 0 to 100 ° C. for 30 minutes to 24 hours for polymerization reaction. A polyamic acid is obtained. In the reaction, the reaction components are dissolved so that the precursor to be produced is in the range of 5 to 30% by weight, preferably in the range of 10 to 20% by weight, in the organic solvent. Examples of the organic solvent used in the polymerization reaction include N, N-dimethylformamide, N, N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone, 2-butanone, dimethyl sulfoxide, dimethyl sulfate, cyclohexanone, and dioxane. , Tetrahydrofuran, diglyme, triglyme and the like. Two or more of these solvents can be used in combination, and further, aromatic hydrocarbons such as xylene and toluene can be used in combination.

The synthesized precursor is usually advantageously used as a reaction solvent solution, but can be concentrated, diluted or replaced with another organic solvent if necessary. Moreover, since a precursor is generally excellent in solvent solubility, it is advantageously used. The method for imidizing the precursor is not particularly limited, and for example, heat treatment in which heating is performed in the above-mentioned solvent under a temperature condition in the range of 80 to 300 ° C. for 1 to 24 hours is suitably employed.

(A) When preparing the polyimide siloxane component, the blending ratio of the acid anhydride component and the diamine component as raw materials is not particularly limited, for example, the terminal substituent of the polyimide siloxane is an amino group, That is, from the viewpoint of sealing the acid anhydride group with diamine and suppressing the polarity of the crosslinked polyimide resin, the molar ratio of acid anhydride component: diamine component is 1.000: 1.001 to 1.0: 1. .2 is preferred.

In addition, (A) component polyimide siloxane has an imide structure obtained by reaction with aromatic tetracarboxylic anhydride, diaminosiloxane and diamine compound, for example, when used as an adhesive for coverlay film, A completely imidized structure is most preferred to suppress copper diffusion. However, a part of the polyimide may be amic acid. The imidization ratio was measured at about 1015 cm ⁻¹ by measuring the infrared absorption spectrum of the polyimide thin film by a single reflection ATR method using a Fourier transform infrared spectrophotometer (commercial product: FT / IR620 manufactured by JASCO Corporation). And the absorbance of C═O stretching derived from an imide group of 1780 cm ⁻¹ , based on the benzene ring absorber.

[Hydrogen bond formation]
Since the polyimidesiloxane obtained as described above has a hydrogen bond-forming group in the molecular structure, hydrogen bonds are generated between adjacent main chains of polyimidesiloxane even at room temperature. For example, when the hydrogen bond forming group contained in the polyimide siloxane is a —NHCO— group, a hydrogen bond is generated between the NH group of one adjacent polyimide siloxane chain and the CO group of the other polyimide siloxane chain. . As a result, a large number of polyimidesiloxane chains can be brought close to a certain degree of orientation, and ketone groups serving as reaction points for a crosslinking reaction with an amino compound can be brought closer between adjacent polyimidesiloxane chains. Such hydrogen bond formation proceeds by keeping the polyimidesiloxane in a solvent solution state, and sufficient hydrogen bonds can be formed to promote the imine crosslinking reaction.

[Amino compound]
In the crosslinked polyimide resin of the present invention, as the amino compound having at least two primary amino groups as functional groups, which is the other component (B) to be reacted with the ketone group of the polyimide siloxane of the component (A), Examples include (I) aromatic diamine, (II) diaminosiloxane, (III) aliphatic amine, (IV) dihydrazide compound, and the like.

(I) Aromatic diamine:
Examples of the aromatic diamine include those represented by the following formulas (12) and (13).

[Wherein R ₁₀ independently represents a monovalent hydrocarbon group or alkoxy group having 1 to 6 carbon atoms, and Z represents a single bond or a divalent hydrocarbon group having 1 to 15 carbon atoms, O, S, CO , SO, SO ₂ , NH or CONH represents a divalent group, and n ₂ independently represents an integer of 0 to 4]

Examples of such aromatic diamines include 4,4′-diaminodiphenyl ether, 2′-methoxy-4,4′-diaminobenzanilide, 1,4-bis (4-aminophenoxy) benzene, 1,3- Bis (4-aminophenoxy) benzene, 2,2′-bis [4- (4-aminophenoxy) phenyl] propane, 2,2′-dimethyl-4,4′-diaminobiphenyl, 3,3′-dihydroxy- Preferred examples include 4,4′-diaminobiphenyl, 4,4′-diaminobenzanilide, bisaniline fluorene and the like.

Further, other examples of aromatic diamines include 2,2-bis- [4- (3-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3 -Aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy)] biphenyl, bis [4- (3-aminophenoxy) biphenyl, bis [1- (4-aminophenoxy)] biphenyl, bis [1- (3-aminophenoxy)] biphenyl, bis [4- (4-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] ether Bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy)] benzophenone, [4- (3-Aminophenoxy)] benzophenone, bis [4,4 ′-(4-aminophenoxy)] benzanilide, bis [4,4 ′-(3-aminophenoxy)] benzanilide, 9,9-bis [ 4- (4-aminophenoxy) phenyl] fluorene, 9,9-bis [4- (3-aminophenoxy) phenyl] fluorene, 2,2-bis- [4- (4-aminophenoxy) phenyl] hexafluoropropane 2,2-bis- [4- (3-aminophenoxy) phenyl] hexafluoropropane, 4,4′-methylenedi-o-toluidine, 4,4′-methylenedi-2,6-xylidine, 4,4 ′ -Methylene-2,6-diethylaniline, 4,4'-diaminodiphenylpropane, 3,3'-diaminodiphenylpropane, 4,4'-diamy Nodiphenylethane, 3,3'-diaminodiphenylethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4 '-Diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, benzidine, 3,3'-diaminobiphenyl, 3, 3′-dimethyl-4,4′-diaminobiphenyl, 3,3′-dimethoxybenzidine, 4,4 ″ -diamino-p-terphenyl, 3,3 ″ -diamino-p-terphenyl, m-phenylene Diamine, p-phenylenediamine, 2,6-diaminopyri 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4 ′-[1,4-phenylenebis (1-methylethylidene)] bisaniline, 4 , 4 ′-[1,3-phenylenebis (1-methylethylidene)] bisaniline, bis (p-aminocyclohexyl) methane, bis (p-β-amino-t-butylphenyl) ether, bis (p-β- Methyl-δ-aminopentyl) benzene, p-bis (2-methyl-4-aminopentyl) benzene, p-bis (1,1-dimethyl-5-aminopentyl) benzene, 1,5-diaminonaphthalene, 2, 6-diaminonaphthalene, 2,4-bis (β-amino-t-butyl) toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5- Examples include diamine, m-xylylenediamine, p-xylylenediamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine and the like. it can. The above aromatic diamines may be used alone or in combination of two or more.

(II) Diaminosiloxane:
As the diaminosiloxane, diaminosiloxane represented by the following general formula (14) or an oligomer thereof is preferably exemplified.

(Where R ₁₁ and R ₁₂ represent a divalent hydrocarbon group, R ₁₃ to R ₁₆ represent a hydrocarbon group having 1 to 6 carbon atoms, and m ₁ represents a number of 1 to 20, preferably 1 to Indicates a number of 10.)

Examples of such diaminosiloxanes include diaminopropyltetramethyldisiloxane and diaminosiloxanes represented by the above general formulas (5) to (9). The above diaminosiloxanes may be used alone or in combination of two or more.

(III) Aliphatic amines:
Examples of the aliphatic amine include 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 2-methyl-1,5-diaminopentane, 1,7-diaminoheptane, and 1,8. Diaminooctane, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12- Diaminoalkanes such as diaminododecane, 4,4′-methylenebiscyclohexylamine, tris (2-aminoethyl) amine, N, N′-bis (2-aminoethyl) -1,3-propanediamine, bis (3 -Aminopropyl) ethylenediamine, 1,4-bis (3-aminopropyl) piperazine, diethylenetriamine, N-methyl-2,2'-dia Nodiethylamine, amines containing nitrogen atoms such as 3,3′-diaminodipropylamine, N, N-bis (3-aminopropyl) methylamine, bis (3-aminopropyl) ether, 1,2-bis Amines containing oxygen atoms such as (2-aminoethoxy) ethane, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxaspiro [5.5] -undecane, Examples thereof include amines having a sulfur atom such as 2′-thiobis (ethylamine). The above aliphatic amines may be used alone or in combination of two or more.

(IV) Dihydrazide compound:
Examples of the dihydrazide compound include those represented by the following general formula (15).

In the general formula (15), examples of R ₁₇ include a single bond, an aliphatic group, and an aromatic group. What is preferable as R ₁₇ is described with reference to examples of dihydrazide compounds. For example, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide dihydrazide, maleic acid dihydrazide Diglycolic acid dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2,6-naphthodioic acid dihydrazide, 4,4-bisbenzene dihydrazide, 1,4-naphthoic acid dihydrazide, Examples include 2,6-pyridinedioic acid dihydrazide, itaconic acid dihydrazide and the like. The above dihydrazide compounds may be used alone or in combination of two or more.

Among the amino compounds having at least two primary amino groups as functional groups as described above, dihydrazide compounds are most preferable. When the dihydrazide compound is used, the curing time of the adhesive resin composition can be shortened as compared with the case where another amino compound is used. This is because the product obtained by reacting the primary amino group of the dihydrazide compound with the ketone group has a semicarbazone-like molecular structure, and forms a dimer structure by hydrogen bonding between NHs between molecules. Because the stability of the product is improved, the equilibrium of the reaction is biased toward the product side, and the reverse reaction in the direction of generating the ketone group of the polyimidesiloxane that is the raw material and the amino group of the dihydrazide compound is less likely to occur. It is considered a thing.

In addition, amino compounds such as (I) aromatic diamine, (II) diaminosiloxane, (III) aliphatic amine, and (IV) dihydrazide compound are, for example, combinations of (I) and (II), (I) and ( It can also be used in combination of two or more types across categories, such as combinations with (III), combinations of (I), (II) and (III), and combinations of (I) to (IV). In particular, by combining the amino compound (I), (II) or (III) and the dihydrazide compound (IV) at a predetermined blending ratio, while taking advantage of the properties of the amino compounds (I) to (III) It is expected to obtain an effect of shortening the curing time depending on the blending ratio of the dihydrazide compound (IV).

Further, from the viewpoint of making the network structure formed by crosslinking of the amino compound more dense, the amino compound used in the present invention has a molecular weight (weight average molecular weight when the amino compound is an oligomer) of 5,000 or less. It is preferably 90 to 2,000, more preferably 100 to 1,500. Of these, amino compounds having a molecular weight of 100 to 1,000 are particularly preferred. When the molecular weight of the amino compound is less than 90, one amino group of the amino compound only forms a C = N bond with the ketone group of the polyimide siloxane, and the remaining amino group is sterically bulky so that it remains. The amino group tends to be difficult to bond C═N.

[Method for producing crosslinked polyimide resin]
The method for producing a crosslinked polyimide resin of the present invention comprises mixing the acid anhydride component having a ketone group, the diamine compound having a hydrogen bond-forming group and a diamine component containing diaminosiloxane, which is the component (A), A step of imidizing by heating to form a polyimide siloxane having a ketone group and a hydrogen bond-forming group;
Forming hydrogen bonds between adjacent main chains in the polyimidesiloxane;
By reacting at least a part of the ketone group of the polyimidesiloxane with the amino group of the amino compound having at least two primary amino groups as the functional group as the component (B), a C═N bond is formed, and the polyimidesiloxane is formed. And crosslinking with an amino compound. Specifically, an amino acid containing at least two primary amino groups of component (B) as a functional group in a resin solution containing polyimide siloxane of component (A) and having hydrogen bonds formed between the main chains. It is produced by adding a compound and subjecting some or all of the ketone groups of polyimidesiloxane to a condensation reaction with the primary amino group of the amino compound. By this condensation reaction, the crosslink formation proceeds between the polyimidesiloxane chains, and the adhesive resin composition is gradually cured according to the degree of crosslink formation. In this case, the total amount of primary amino groups is 0.004 mol to 1.5 mol, preferably 0.005 mol to 1.2 mol, more preferably 0.03 mol to 0.00 mol per mol of the ketone group. It is preferable to add the amino compound so as to be 9 mol, particularly preferably 0.04 mol to 0.5 mol. The addition amount of the amino compound in which the primary amino group is less than 0.004 mol in total with respect to 1 mol of the ketone group is not sufficient for crosslinking of the polyimide siloxane with the amino compound. Solder heat resistance tends to be difficult to develop in the cured product after curing, and when the added amount of amino compound exceeds 1.5 mol, the unreacted amino compound acts as a thermoplastic agent, and solder heat resistance in the cured product. There is a tendency to lower the long-term heat resistance at high temperatures.

Further, the curing by the condensation reaction is not particularly limited as long as the conditions allow the ketone group in the polyimidesiloxane and the primary amino group of the amino compound to react to form an imine bond (C═N bond). Depending on the type of amino compound, for example, when an aliphatic amine is used, it can be condensed with a ketone group in polyimide siloxane even at room temperature, but it is preferable to promote the condensation reaction by heating. When an aliphatic amine is used as the amino compound, it is preferable to perform heat condensation within the range of 60 to 200 ° C., for example. When an aromatic amine is used, the heat condensation is performed within the range of 120 to 220 ° C., for example. It is preferable to carry out. The temperature of the heat condensation is, for example, 120 for the purpose of releasing water generated by the condensation out of the system or simplifying the condensation step when the heat condensation reaction is subsequently performed after the synthesis of the polyimidesiloxane. It is preferably in the range of -220 ° C, more preferably in the range of 140-200 ° C. The reaction time is preferably about 0.5 to 24 hours. From the viewpoint of obtaining practically sufficient moisture-resistant soldering heat resistance by a short heat treatment, it is preferable to heat at 160 ° C. or higher for 0.5 hour or longer. Then, from the viewpoint of obtaining practically sufficient moisture-resistant soldering heat resistance by a lower temperature heat treatment, it is desirable to heat at 150 ° C. or higher for 1 hour or longer.

The end point of the condensation reaction is derived from the ketone group in polyimidesiloxane near 1670 cm ⁻¹ by measuring the infrared absorption spectrum using, for example, a Fourier transform infrared spectrophotometer (commercial product: FT / IR620 manufactured by JASCO). It can be confirmed by the decrease or disappearance of the absorption peak and the appearance of an absorption peak derived from an imine group near 1635 cm ⁻¹ , or by using a Raman spectrophotometer (commercial product: NRS-3100 manufactured by JASCO Corporation) By measuring the spectrum, it can be confirmed by the appearance of a peak derived from an imine group near 1567 cm ⁻¹ . Further, whether or not a practically sufficient moisture-resistant soldering heat resistance can be exhibited by heat treatment at 160 ° C. for 2 hours can be determined by using the viscosity of the formed crosslinked polyimide resin as an index. For example, when the molecular weight of the polyimide resin is in the range of 70,000 to 140,000, the viscosity of the polyimide resin to which a crosslinking agent is added at a temperature of 260 ° C. is preferably 1 × 10 ⁵ Pa · s or more. If the viscosity of the cross-linked polyimide resin at a temperature of 260 ° C. is 1 × 10 ⁵ Pa · s or more, it can be considered that the cross-linking is formed to such an extent that practically sufficient moisture-resistant soldering heat resistance can be obtained. The reason why the viscosity of the cross-linked polyimide resin is employed as the threshold value is that it is difficult to directly measure the cross-linking formation rate due to C═N bonds. Second, since the cross-linking formation rate (ketone group consumption rate) necessary to obtain practically sufficient moisture-resistant solder heat resistance varies depending on the molecular weight of the cross-linked polyimide resin, it is simply determined by the cross-linking formation rate. It is difficult to judge the moisture-resistant solder heat resistance in the crosslinked polyimide resin of the invention. However, if the viscosity of the crosslinked polyimide resin at a temperature of 260 ° C. is 1 × 10 ⁵ Pa · s or more, it is considered that the practically sufficient moisture-resistant soldering heat resistance has been obtained. The viscosity at this time is adopted as a standard for judging the end point of the curing by the condensation reaction. Therefore, the end point of the condensation reaction does not necessarily mean that all of the ketone groups are consumed and further curing does not proceed, but a cured product having practically sufficient properties (especially moisture solder heat resistance) ( It means the time when a semi-cured product is obtained.

The heat condensation of the ketone group of polyimidesiloxane and the primary amino group of the amino compound is, for example,
(A) Following the synthesis (imidation) of polyimide siloxane, adding an amino compound and heating,
(B) charging an excess amount of an amino compound in advance as a diamine component and heating the polyimide siloxane together with the remaining amino compound not involved in imidization (or amidation) following the synthesis (imidation) of the polyimide siloxane; Or
(C) heating after processing the polyimidesiloxane composition to which the amino compound has been added into a predetermined shape (for example, after being applied to an arbitrary base material or after being formed into a film),
Etc.

In the case of (b) above, the excess amino compound is consumed in the reaction of sealing the acid anhydride group as a terminal substituent during the production of polyimidesiloxane, and the molecular weight of the resulting polyimidesiloxane may be extremely reduced. Therefore, it tends to be difficult to obtain sufficient heat resistance in the cured product. Therefore, it is preferable to use the method [the above (b)] in which an excess amount of an amino compound is previously charged as long as the effect of the present invention is not impaired. In order to effectively react at least two primary amino groups in an amino compound with a ketone group to form a C═N bond, the amino compound is synthesized from polyimide siloxane as in (a) or (c) above. It is preferable to add after completing (imidization). In the case of (c) above, the heat condensation is performed by, for example, the heat of heat treatment performed when the adhesive layer of the coverlay film is formed from a composition in which an amino compound and polyimide siloxane are mixed, or the adhesive layer is formed. After that, it can also be performed by using heat at the time of thermocompression bonding to the circuit board having the wiring layer.

[Inorganic filler]
The cross-linked polyimide resin of the present invention can contain a plate-like inorganic filler having an average particle size in the range of 2 to 25 μm as an optional component (C). (C) By blending the component inorganic filler, when the crosslinked polyimide resin is used for, for example, the adhesive layer of the coverlay film, the permeation of oxygen in the atmosphere is blocked by the inorganic filler having gas barrier properties. In addition, oxidation of copper wiring and copper diffusion are suppressed, and long-term heat resistance can be improved.

As the inorganic filler of component (C), it is preferable to use a plate-like material in order to impart sufficient gas barrier properties to the adhesive layer. Here, the “plate shape” is used to mean, for example, a flat shape, a flat plate shape, a flake shape, a scale shape, etc., and the thickness of the inorganic filler is sufficiently smaller than the major axis or minor axis of the plane portion (preferably 1/2 or less). In particular, it is preferable to use a scale-like inorganic filler. From another viewpoint, “plate-like” means that the ratio of the major axis to the thickness (major axis / thickness) of the filler particles is preferably 5 or more, more preferably 10 or more, and still more preferably 15 or more. In the plate-like inorganic filler, the relationship between the long diameter and the average particle diameter is preferably long diameter ≧ average particle diameter> 0.4 × long diameter, more preferably long diameter ≧ average particle diameter ≧ 0.5 ×. It is good that it is a long diameter. In the present invention, the major axis (or minor axis) and thickness of the filler particles, and the ratio of the major axis to the thickness are the average values when ten arbitrary fillers are measured with a stereomicroscope. If the shape of the inorganic filler is not plate-like, for example, it is spherical, the gas barrier property of the adhesive layer is lowered, the oxidation of the wiring layer proceeds, and the adhesive strength of the coverlay film may be reduced. It does not preclude blending inorganic fillers having a shape other than the plate shape as long as the effect of blending the plate filler is not impaired.

As the inorganic filler of component (C), it is preferable to use an insulating inorganic filler such as talc, mica, sericite, clay, kaolin and the like.

The inorganic filler preferably has an average particle diameter calculated by a laser diffraction method in the range of 2 to 25 μm, and more preferably in the range of 5 to 20 μm. Here, the particle size of the inorganic filler is based on the average value of the longitudinal diameters of the particles. When the average particle diameter exceeds the upper limit, the surface roughness of the adhesive layer of the coverlay film tends to occur. When the average particle diameter is less than the lower limit, it is difficult to obtain the effect of suppressing oxygen transmission.

In addition, the particle size distribution of the inorganic filler is preferably 60% or more, more preferably 65% or more, and preferably the particle size of 20 μm or more is 10% or less on a number basis. When the inorganic filler having a particle diameter of 10 μm or less is less than 60%, when the adhesive resin composition is formed into a film, the fillers are arranged in layers, and protrusions appear on the film surface, which causes the film surface to become rough. In addition, if the inorganic filler having a particle size of 20 μm or more exceeds 10%, protrusions appear on the film surface, causing the surface of the film to become rough. For example, when a thin film of 15 μm or less is produced, the surface tends to be rough. Cheap. The frequency distribution of the particle size of the inorganic filler is preferably from 0.1 to 100 μm, more preferably from 0.5 to 70 μm. If the frequency distribution exceeds the upper limit, the surface of the adhesive layer tends to be rough, and if the frequency distribution is lower than the lower limit, it is difficult to obtain the effect of suppressing oxygen transmission.

The compounding amount of the inorganic filler of component (C) is 5 to 200 parts by weight, preferably 10 to 150 parts by weight, based on 100 parts by weight of the total of component (A) and component (B). The amount is preferably 30 to 100 parts by weight, and desirably 40 to 80 parts by weight. When the blending amount of the inorganic filler is less than 5 parts by weight with respect to 100 parts by weight of the total of the component (A) and the component (B), the blending effect cannot be obtained, and the effect of suppressing oxygen permeation cannot be obtained. Moreover, when the compounding quantity of an inorganic filler exceeds 200 weight part with respect to a total of 100 weight part of said (A) component and (B) component, an adhesive bond layer will become weak, As a result, cohesive failure in an adhesive bond layer As a result, the apparent adhesiveness is significantly reduced. In the present invention, a plate-like inorganic filler is used, but it is also possible to use a non-plate-like inorganic filler in combination. When the inorganic filler that is not plate-shaped is used in combination, the total amount of the inorganic filler (plate-shaped and other shapes total) exceeds 200 parts by weight with respect to 100 parts by weight of the total of component (A) and component (B). It is preferable not to do so.

[Action]
The reaction between the ketone group of the polyimide siloxane of the component (A) and the primary amino group of the amino compound is a dehydration condensation reaction, and the carbon atom of the ketone group and the nitrogen atom of the primary amino group in the polyimide siloxane are As a result of forming a C = N bond, it is considered that a chain polyimidesiloxane is crosslinked with an amino compound to form a network polymer. Preferably, by including a hydrogen bond-forming group in the polyimide siloxane of the component (A), a hydrogen bond is generated between adjacent polyimide siloxane chains prior to the crosslinking reaction, and the reaction point of the crosslinking reaction with the amino compound. Can be brought close to each other. As a result, the crosslinking reaction by the amino compound is promoted, and the heating time until a practically sufficient moisture-resistant soldering heat resistance is obtained can be shortened. Usually, since polyimidesiloxane hardly causes intermolecular interaction, it is difficult to control the orientation of polyimidesiloxane, but by including a hydrogen bond forming group in the main chain, a hydrogen bond can be generated. Furthermore, when a crosslinked structure of a ketone group and an amino compound occurs, not only the apparent high molecular weight in polyimide siloxane but also the polyimide siloxane molecules can be constrained to some extent, thus improving the heat resistance, It is considered that extremely excellent solder heat resistance can be obtained. In addition, the vicinity of the nitrogen atom in the C = N bond becomes three-dimensionally bulky, thereby reducing the nucleophilic ability of the copper atom of the polar group contained in the crosslinked polyimide resin, so that the copper adhesive layer from the copper wiring It is thought that the effect of suppressing the decrease in the adhesive strength when used in a high temperature environment can be obtained. For these reasons, the amino compound used in the present invention must have at least two amino groups, and the number of amino groups is preferably 2 to 5, more preferably 2 to 3. In addition, in an amino compound having three or more amino groups, the cross-linked structure after the two amino groups form a C═N bond becomes three-dimensionally bulky, so that the remaining unreacted amino group is a ketone group. It is particularly preferable that the number of amino groups is 2. Furthermore, from the viewpoint of shortening the curing time of the adhesive resin composition as described above, it is most preferable to use a dihydrazide compound as the amino compound.

[Adhesive resin composition]
The adhesive resin composition of the present invention contains the polyimidesiloxane [(A) component] and an amino compound [(B) component] having at least two primary amino groups as functional groups as essential components. To do. This adhesive resin composition is obtained by mixing or kneading the component (A) and the component (B) and / or heating in a state containing the component (A) and the component (B). And the primary amino group of the amino compound undergo a condensation reaction to form a C═N bond. That is, the adhesive resin composition of the present invention changes to the cured product of the present invention by a condensation reaction between polyimide siloxane and an amino compound. Here, the “cured product” of the present invention is not only a state in which the crosslinking reaction between the ketone group of the polyimide siloxane and the primary amino group of the amino compound does not proceed any further, Including the semi-cured state leaving room. In the adhesive resin composition of the present invention, the weight average molecular weight of the component (A) is preferably in the range of 30,000 to 200,000, for example. From the viewpoint of obtaining properties, it is more preferably within the range of 70,000 to 140,000. When the weight average molecular weight of the component (A) is less than 70,000, it becomes difficult to control the fluidity when the adhesive resin composition is made into a solution, and the heat resistance of the cured product tends to decrease. . On the other hand, when the weight average molecular weight exceeds 140,000, the solubility in the solvent tends to be impaired.

The adhesive resin composition has a total of primary amino groups of 0.004 mol to 1.5 mol, preferably 0.005 mol to 1.2 mol, more preferably 0.03 mol per mol of ketone groups. The amino compound is contained in an amount of from mol to 0.9 mol, particularly preferably from 0.04 mol to 0.5 mol.

The adhesive resin composition of the present invention preferably contains the inorganic filler of the component (C) as an optional component together with the polyimide siloxane of the component (A) and the amino compound of the component (B). Further, if necessary, other resin components such as an epoxy resin, a curing accelerator, a coupling agent, a filler, a pigment, a solvent, a flame retardant and the like can be appropriately blended. However, some plasticizers contain a large number of polar groups, and there is a concern that this may promote the diffusion of copper from the copper wiring. Therefore, it is preferable not to use the plasticizer as much as possible.

In the case where an optional component other than the inorganic filler of component (C) is blended in the adhesive resin composition of the present invention, for example, the blending amount of 1 to 10 parts by weight in total of the optional component is 100 parts by weight of the crosslinked polyimide resin The blending amount is preferably 2 to 7 parts by weight.

The adhesive resin composition of the present invention obtained as described above has excellent flexibility and thermoplasticity when it is used to form an adhesive layer, such as FPC, rigid flex circuit board, etc. It has preferable characteristics as an adhesive for a coverlay film that protects the wiring part. When used as an adhesive layer of a cover lay film, the adhesive resin composition of the present invention is applied in the form of a solution (for example, a varnish containing a solvent) to one side of a cover lay film material. By carrying out thermocompression bonding at a temperature of 220 ° C., the coverlay film of the present invention having a coverlay film material layer and an adhesive layer can be formed. In this case, it is possible to heat-condense the ketone group of the polyimide siloxane and the primary amino group of the amino compound using heat at the time of thermocompression bonding. Moreover, even when heat condensation at the time of thermocompression bonding is not sufficient, heat treatment can be further performed after thermocompression bonding for heat condensation. When heat treatment is performed after thermocompression bonding, the heat treatment temperature is preferably 60 to 220 ° C, for example, and more preferably 80 to 200 ° C. Further, the adhesive resin composition of the present invention is applied on an arbitrary substrate in a solution state (for example, a varnish containing a solvent), dried at a temperature of, for example, 80 to 180 ° C., and then peeled off. The film having the coverlay film material layer and the adhesive layer can also be formed by thermocompression bonding the adhesive film with the coverlay film material at a temperature of 60 to 220 ° C., for example. The coverlay film of the invention can be formed. In this case as well, the ketone group of the polyimide siloxane and the primary amino group of the amino compound can be heat-condensed using the heat during thermocompression bonding. As described above, the adhesive resin composition of the present invention can be used after being processed into various forms in a state where the ketone group of polyimidesiloxane and the primary amino group of the amino compound are unreacted. Furthermore, the adhesive resin composition of the present invention can be used by forming a coating film in the form of a solution by screen printing on an arbitrary substrate and drying it at a temperature of 80 to 180 ° C., for example. . Preferably, a cured product can be formed by further heat-treating at a temperature of 130 to 220 ° C. for a predetermined time to completely cure the coating film.

[Coverlay film / bonding sheet]
The coverlay film of the present invention includes a coverlay film material and an adhesive layer composed of the adhesive resin composition laminated on the coverlay film material. The film material for the coverlay in the coverlay film of the present invention is not limited, but, for example, a polyimide resin film such as a polyimide resin, a polyetherimide resin, a polyamideimide resin, a polyamide resin film, or a polyester resin. A film or the like can be used. Among these, it is preferable to use a polyimide resin film having excellent heat resistance. The thickness of the coverlay film material layer is not particularly limited, but is preferably 5 μm or more and 100 μm or less, for example. The thickness of the adhesive layer is not particularly limited, but is preferably 10 μm or more and 50 μm or less, for example.

Moreover, what formed the adhesive resin composition of this invention in the film form can be utilized also as a bonding sheet of multilayer FPC, for example. When used as a bonding sheet, an adhesive film obtained by coating the adhesive resin composition of the present invention in the form of a solution on an arbitrary base film, drying at a temperature of, for example, 80 to 180 ° C., and then peeling. May be used as a bonding sheet as it is, or may be used in a state where this adhesive film is laminated with an arbitrary substrate film. Also when used as a bonding sheet, the heat of thermocompression bonding can be used to heat-condense the polyimidesiloxane ketone group and the primary amino group of the amino compound. Heat condensation can also be performed.

Also, the coverlay film and the bonding sheet may have a release material layer by bonding a release material to the adhesive surface. The material of the release material is not particularly limited as long as it can be peeled without impairing the form of the coverlay film or the bonding sheet. For example, resin films such as polyethylene terephthalate, polyethylene, and polypropylene, and these resin films And the like laminated on paper can be used.

The coverlay film or bonding sheet obtained by molding using the adhesive resin composition of the present invention and causing the heat condensation reaction by heat treatment is a cross-linked polyimide resin obtained by reaction of polyimidesiloxane and an amino compound. Therefore, it has excellent solder heat resistance. More specifically, as shown in Examples below, the solder heat resistance (drying) is 260 ° C. or higher, preferably 280 ° C. or higher, more preferably 300 ° C. or higher, and the solder heat resistance (humidity resistance) is 200 ° C. or higher. The temperature is preferably 260 ° C. or higher, more preferably 280 ° C. or higher. Thus, by having extremely excellent solder heat resistance, the occurrence of deformation or peeling in the soldering process is prevented, and it is possible to contribute to the improvement of the yield and reliability of the circuit board to be manufactured.

[Circuit board]
As long as the circuit board of this invention is provided with the coverlay film and bonding sheet which are obtained as mentioned above, there is no restriction | limiting in particular in the structure. For example, the preferred form of the circuit board of the present invention is at least a base material, a wiring layer made of a metal such as copper formed in a predetermined pattern on the base material, and the cover lay film of the present invention covering the wiring layer And has. The base material of the circuit board is not particularly limited, but in the case of FPC, it is preferable to use the same material as the coverlay film material, and it is preferable to use a polyimide resin base material.

By using the cover lay film of the present invention, the circuit board of the present invention is filled with an adhesive layer having excellent flexibility and thermoplasticity between the wirings, and high adhesion between the cover lay film and the wiring layer is obtained. It is done. In addition, by forming an adhesive layer containing a cross-linked polyimide resin obtained by the reaction of polyimide siloxane and amino compound, copper diffusion from the copper wiring is suppressed, even if repeated use in a high temperature environment, Excellent adhesion can be maintained over a long period of time. More specifically, after a long-term heat resistance test at 150 ° C. and 1000 hours in the atmosphere, the measurement of the energy dispersive X-ray (EDX) analyzer (see Examples below) shows that the copper on the adhesive layer The amount of diffusion can be suppressed to 2.5% or less. As a result, it is possible to maintain the peel strength between the copper wiring layer and the coverlay film material layer after the long-term heat resistance test at 0.2 kN / m or more. In particular, by selecting the group Ar, the group R ₁ and the group R ₂ in the general formulas (1) and (2), it is possible to obtain an extremely high peel strength of 0.4 kN / m or more. Also, by setting the blending ratio of diaminosiloxane to the total diamine component of the raw material to 35 mol% or more, it is possible to obtain excellent solubility and prevent warping of the coverlay film without blending a plasticizer. it can.

Further, the circuit board of the present invention may be configured as a multilayer circuit board. In this case, the adhesive film obtained from the adhesive resin composition of the present invention can be used not only for the coverlay film but also for the bonding sheet.

The production of the circuit board of the present invention is not particularly limited. For example, after the metal foil of a metal-clad laminate such as a copper-clad laminate is processed into a predetermined pattern by a method such as chemical etching, the circuit is produced. For example, a method of laminating a cover lay film on the necessary portion above and performing thermocompression bonding using, for example, a hot press apparatus can be used. In this case, the pressure bonding conditions are not particularly limited. For example, the pressure bonding temperature is preferably 130 ° C. or higher and 220 ° C. or lower, more preferably 140 ° C. or higher and 200 ° C. or lower, and the pressure is 0.1 MPa or higher and 4 MPa or lower. It is preferable. In addition, when the ketone group of polyimide siloxane and the primary amino group of the amino compound are unreacted in the state of the cover lay film, condensation is performed using heat when the cover lay film is thermocompression bonded to the circuit wiring. A reaction can be caused. That is, it arrange | positions so that the adhesive bond layer of a coverlay film may contact | connect a wiring layer, and the process of carrying out the thermocompression bonding of both members, and the ketone group of (A) component contained in an adhesive bond layer, and (B) component It is possible to carry out a condensation reaction with a primary amino group to form a C═N bond.

Next, an embodiment in which the crosslinked polyimide resin of the present invention is applied to a thermally conductive substrate and a thermally conductive polyimide film will be described.

With the recent miniaturization of electronic devices, the degree of circuit integration has increased, and in conjunction with the speeding up of information processing, heat dissipation means for heat generated in the device has attracted attention. In addition, with the growing awareness of environmental issues such as global warming, there is a strong demand for products with low environmental impact and energy saving. A typical example is the rapid spread of LED lighting in place of incandescent lamps, but in order to fully demonstrate the performance of LED lighting, it is important to efficiently release the heat generated during use. . Further, in SiC, which is a power semiconductor material used for in-vehicle applications, it is important to efficiently release heat generated during use in order to operate at a high temperature. Then, in order to provide the circuit board which was rich in workability and excellent in heat dissipation, about the polyimide film which comprises an insulating layer, examination which improves the thermal conductivity of the thickness direction is made | formed.

However, the thermal conductivity in the thickness direction of the conventional polyimide film is insufficient in performance as a heat radiating substrate and needs to be improved. In general, when a metal-clad laminate is produced by laminating a resin layer on a metal layer such as copper foil, an adhesive layer made of an epoxy adhesive or a thermoplastic resin is usually provided between the metal layer and the resin layer. There is a need. The interposition of the adhesive layer not only causes a further decrease in the heat dissipation generated in the metal layer, but also causes a decrease in various properties such as heat resistance and flexibility required for use as a practical substrate. Although a substrate material and a film material in which a heat conductive filler is mixed with a polyimide resin are known in this way, when a heat-resistant polyimide resin is to be thermocompression-bonded with another member, it is performed under a high pressure condition. This is necessary, and there is a concern that it may cause a lack of wiring, damage to parts, and the like. In addition, when a thermally conductive filler is blended with siloxane polyimide, the above-mentioned conditions of high-temperature pressurization are relaxed, but sufficient heat resistance, particularly long-term heat resistance cannot be ensured, and heat dissipation used in a high-temperature environment. It is considered unsuitable for application as a main resin layer of a substrate.

Therefore, there is no need for an adhesive layer, it has practical adhesive strength between the insulating layer and the metal layer, ceramic substrate, Si substrate, and other base materials, and the thermal conductivity of the insulating layer, (long-term) heat resistance It has been desired to provide a heat conductive substrate excellent in heat resistance, and a heat conductive polyimide film that can give the above-mentioned characteristics to the heat conductive substrate and has thermocompression bonding properties in a relatively low temperature region. In this embodiment, heat having a practical adhesive strength between an insulating layer and a metal layer, a ceramic substrate, a Si substrate, or other base material, and excellent in thermal conductivity and (long-term) heat resistance of the insulating layer. Provided is a conductive substrate, and a thermally conductive polyimide film having thermocompression bonding properties in a relatively low temperature region in addition to this property.

[Thermal conductive substrate]
The thermally conductive substrate of one embodiment of the present invention has at least one filler-containing polyimide resin layer in which a thermally conductive filler is dispersed in a polyimide resin. The insulating layer only needs to have at least one filler-containing polyimide resin layer. The insulating layer has a metal layer on one side or both sides. The filler-containing polyimide resin layer contains a thermally conductive filler in the above-mentioned crosslinked polyimide resin. The polyimide resin constituting the filler-containing polyimide resin layer has a cross-linked structure by a C═N bond with an amino compound. A resin layer having an insulating layer made of a filler-containing polyimide resin layer in which the crosslinking formation rate (degree of curing) of this crosslinked structure is controlled can be provided with adhesiveness to the resin layer. It can be used as an attached copper foil, that is, as a copper foil with a heat conductive resin, adhered to another substrate.

[Insulation layer]
The insulating layer only needs to have at least one filler-containing polyimide resin layer in which a thermally conductive filler is dispersed in a cross-linked polyimide resin. In addition to the filler-containing polyimide resin layer, other polyimide resins laminated thereon A layer may be provided. In this case, the crosslinked polyimide resin constituting the filler-containing polyimide resin layer and the polyimide resin constituting the other polyimide resin layer in the insulating layer may be the same type of polyimide resin or different types of polyimide resins. The kind of polyimide resin in the case of using different types of polyimide resins as other polyimide resin layers other than the filler-containing polyimide resin layer is not particularly limited. However, from the viewpoint of enhancing the heat dissipation characteristics of the thermally conductive substrate, the entire insulating layer is preferably formed of a filler-containing polyimide resin layer. In this case, the filler-containing polyimide resin layer is not limited to a single layer, and may be a laminate of a plurality of layers.

[Thermal conductive filler]
In the present embodiment, the content ratio of the thermally conductive filler in the filler-containing polyimide resin layer needs to be in the range of 5 to 80 wt%, and preferably in the range of 10 to 60 wt%. If the content of the heat conductive filler is less than 5 wt%, the heat dissipation characteristics when the electronic component such as a circuit board is not sufficient, and if it exceeds 80 wt%, the decrease in folding resistance and bending resistance becomes significant. Moreover, the intensity | strength of a filler containing polyimide resin layer also falls.

As the thermally conductive filler, a highly thermally conductive filler is preferable, and specifically, for example, aluminum, copper, nickel, silica, diamond, alumina, magnesia, beryllia, boron nitride, aluminum nitride, silicon nitride, silicon carbide, etc. Can be mentioned. Among these, at least one filler selected from silica, alumina, aluminum nitride, boron nitride, silicon nitride, and magnesia is preferable. Since the filler-containing polyimide resin layer acts as an insulating layer, from that point of view, an insulating filler is suitable for the polyimide resin layer. The filler shape is not particularly limited, and may be, for example, a plate shape (including a flake shape), a spherical shape, a needle shape, or a rod shape. Moreover, considering the balance with characteristics such as thermal conductivity by increasing the content of the thermal conductive filler, fillers having different shapes (for example, plate-like and spherical, plate-like and needle-like) can be used in combination. .

The size of the thermally conductive filler is, for example, in the range of an average particle diameter of 0.5 to 10 μm from the viewpoint of improving the thermal conductivity by uniformly dispersing the filler in the thickness direction of the filler-containing polyimide resin layer. Is more preferable, and is more preferably within a range of 0.8 to 5 μm. If the average particle diameter of the thermally conductive filler is less than 0.5 μm, the heat conduction inside each filler is reduced, and as a result, the thermal conductivity of the filler-containing polyimide resin layer is not improved, and the particles are Aggregation tends to occur, and it may be difficult to uniformly disperse. On the other hand, when it exceeds 10 μm, the filling rate into the filler-containing polyimide resin layer is lowered, and the filler-containing polyimide resin layer tends to be brittle at the filler interface.

[Crosslinked polyimide resin and polyimidesiloxane]
The polyimide resin for forming the filler-containing polyimide resin layer is the cross-linked polyimide resin, preferably a group Ar and / or group in polyimide siloxane having the structural units represented by the general formulas (1) and (2). A structure in which polyimide siloxane is crosslinked by an amino compound by reacting the ketone group in R ₂ with an amino compound having at least two primary amino groups as functional groups to form a C═N bond. Is. In this case, the abundance of the structural unit represented by the formula (1) in the resin is in the range of 40 mol% to 100 mol%, preferably in the range of 80 mol% to 100 mol%.

In a preferred embodiment of the thermally conductive substrate of the present invention, a hydrogen bond forming group can be contained in the general formulas (1) and (2).

The general formula (1), in the polyimide siloxanes having a structural unit represented by (2), during the group Ar and / or groups R _2, include a ketone group, the ketone group is, for reaction with the amino compound concern. In this case, it is only necessary that the amino group of the amino compound reacts with at least a part of the ketone group in the group Ar and / or the group R ₂ in the polyimidesiloxane to form a C═N bond. The crosslinking formation rate (degree of curing) of the polyimide resin may not be a state in which the curing of the polyimide resin by the crosslinking formation is completed, and may be a level that can ensure practically sufficient heat resistance. That is, the polyimide resin may be in a cured state where the crosslinking reaction has been completed, or may be in a semi-cured state in which room for crosslinking is left. By keeping the cured state in a semi-cured state, the resin layer can be provided with adhesiveness and can be made suitable for the use of the resin-coated copper foil. Whether or not the cross-linked polyimide resin has practically sufficient heat resistance can be determined using, for example, viscosity as an index.

In addition, if the filler-containing polyimide resin layer has a constant filler content, the adhesiveness is relatively high when the crosslinking formation rate of the crosslinked polyimide resin is low, and relatively high when the crosslinking formation rate of the crosslinking polyimide resin is high. There is a tendency for adhesion to be low. Therefore, it is also possible to determine the crosslinking formation rate of the crosslinked polyimide resin using, for example, the peel strength (bonding surface adhesion strength) with the copper foil after thermocompression bonding as an index. More specifically, after producing a heat conductive substrate having a metal layer on one side, a rolled copper foil (surface roughness Ra = 0.7 μm) having a thickness of 18 μm is formed on the polyimide resin layer of the heat conductive substrate. And press under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours. Then, a 180 ° peel test is performed in accordance with “copper foil peel strength (peel strength)” shown in Examples below, and the peel strength between the rolled copper foil and the polyimide resin layer is measured. At this time, for example, when the filler content is 80 wt% and the peel strength is 0.4 [kN / m] or more, it is set as a semi-cured state in which the crosslinking is not completed (a state in which room for crosslinking is left), A case where the filler content is 5 wt% and the peel strength is 0.4 [kN / m] or less can be determined as a cured state in which the cross-linking is completed. The “cured state in which the cross-linking has been completed” is a state in which the cross-linking rate is 100% (a state in which the ketone group in the group Ar and / or the group R ₂ in the polyimidesiloxane completely forms a C═N bond). ), And means that the crosslinking reaction does not proceed any more even when the heat treatment is performed under the pressing conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours.

In addition, examples of the group R ₁ in the structural unit represented by the general formula (1) include a diaminosiloxane residue derived from the diaminosiloxane represented by the above formula (4).

The diaminosiloxane residue is a group having a siloxane bond (Si—O—Si) obtained by removing an amino group from diaminosiloxane. By increasing the ratio of the siloxane bond, a plasticizer can be added. Sufficient flexibility is imparted to the insulating layer. Moreover, since many polar groups are contained in the plasticizer, as an advantage of not containing the plasticizer, a polyimide resin using a polyimide siloxane having structural units represented by the general formulas (1) and (2) The amount of polar groups contained therein can be suppressed. For this reason, in this Embodiment, the value of m in Formula (1) shall be 0.4 or more, Preferably it is 0.8 or more. If the value of m is less than 0.4, the effect of suppressing warpage cannot be obtained sufficiently. In addition, it is considered that increasing the siloxane bond also has an effect of reducing curing shrinkage due to a decrease in the imide bond site of polyimidesiloxane. For this reason, in the present embodiment, the value of n in the formula (2) is set in the range of 0 to 0.6, preferably 0 to 0.2.

Thus, by introducing the siloxane skeleton into the polyimide using the diaminosiloxane represented by the above general formula (4), the resulting polyimidesiloxane is given fluidity at the time of thermocompression bonding and adhered to a metal layer or the like. Can be improved.

[Production of filler-containing polyimide resin]
The filler-containing polyimide resin is obtained by mixing and uniformly dispersing a heat conductive filler in a resin solution containing polyimide siloxane having the structural units represented by the general formulas (1) and (2). It is produced by adding an amino compound having a primary amino group as a functional group and causing a condensation reaction between the ketone group of polyimidesiloxane and the primary amino group of the amino compound. By this condensation reaction, a cross-linked structure is formed in the polyimide siloxane and cured to a cured product. In this case, the addition amount of the amino compound is 0.004 mol to 1.5 mol, preferably 0.005 mol to 1.2 mol, and more preferably a total of primary amino groups with respect to 1 mol of the ketone group. It is 0.03 mol to 0.9 mol, particularly preferably 0.04 mol to 0.5 mol. The addition amount of the amino compound in which the primary amino group is less than 0.004 mol in total with respect to 1 mol of the ketone group is not sufficient to crosslink the polyimide siloxane with the amino compound. Solder heat resistance tends to be difficult to develop in a cured product after curing a resin composition containing a filler, and when the added amount of the amino compound exceeds 1.5 mol, the unreacted amino compound acts as a thermoplastic agent. However, the cured product tends to reduce solder heat resistance or to reduce long-term heat resistance at high temperatures.

The conditions for the condensation reaction are not particularly limited as long as the ketone group in the polyimidesiloxane and the primary amino group of the amino compound react to form an imine bond (C═N bond). Depending on the type of amino compound, for example, when an aliphatic amine is used, it can be condensed with a ketone group in polyimide siloxane even at room temperature, but it is preferable to promote the condensation reaction by heating. When an aliphatic amine is used, it is preferable to perform heat condensation within a range of 60 to 200 ° C., for example, and when an aromatic amine is used, heat condensation is performed within a range of 120 to 220 ° C., for example. preferable. The temperature of the heat condensation is, for example, 120 for the purpose of releasing water generated by the condensation out of the system or simplifying the condensation step when the heat condensation reaction is subsequently performed after the synthesis of the polyimidesiloxane. It is preferably in the range of -220 ° C, more preferably in the range of 140-200 ° C. The reaction time varies depending on the heat treatment temperature, but can be, for example, in the range of 3 minutes to 30 hours. Here, when it is desired to obtain a high crosslinking rate, it is preferable that the reaction time is, for example, more than 1 hour to about 24 hours in the above temperature range, and when it is desired to keep the crosslinking rate low, the above temperature range. The reaction time is preferably in the range of 3 to 60 minutes, for example, and more preferably in the range of 5 to 30 minutes. The end point of the condensation reaction is derived from the ketone group in polyimidesiloxane near 1670 cm ⁻¹ by measuring the infrared absorption spectrum using, for example, a Fourier transform infrared spectrophotometer (commercial product: FT / IR620 manufactured by JASCO). It can be confirmed by the decrease or disappearance of the absorption peak and the appearance of an absorption peak derived from an imine group near 1635 cm ⁻¹ , or by using a Raman spectrophotometer (commercial product: NRS-3100 manufactured by JASCO Corporation) By measuring the spectrum, it can be confirmed by the appearance of a peak derived from an imine group near 1567 cm ⁻¹ .

The polyimide resin solution containing the above heat conductive filler is prepared, for example, by adding a predetermined amount of each of the heat conductive filler and the amino compound for cross-linking to a polyimide resin solution containing a solvent, and dispersing with a stirrer or the like. And a method of adding an amino compound for cross-linking after adding a diamine and an acid anhydride to form a polyimide resin solution while dispersing a thermally conductive filler in a solvent. preferable. Examples of the solvent include N, N-dimethylacetamide, n-methylpyrrolidinone, 2-butanone, diglyme, xylene, and the like. These may be used alone or in combination of two or more.

In a preferred embodiment, the heat condensation of the ketone group of the polyimide siloxane and the primary amino group of the amino compound is, for example,
(A) Subsequent to the synthesis (imidization) of polyimide siloxane, adding an amino compound and a thermally conductive filler and heating,
(B) An excess amount of an amino compound is charged in advance as a diamine component, and after the synthesis (imidation) of polyimide siloxane, a thermally conductive filler is added, and then the remaining amino acid not involved in imidization (or amidation) Heating the polyimide siloxane with the compound, or
(C) heating after processing the composition of polyimide siloxane to which an amino compound and a thermally conductive filler are added into a predetermined shape (for example, after being applied to an arbitrary substrate or after being formed into a film),
Etc.

In the case of (b) above, the excess amino compound is consumed in the reaction of sealing the acid anhydride group as a terminal substituent during the production of polyimidesiloxane, and the molecular weight of the resulting polyimidesiloxane may be extremely reduced. Therefore, it tends to be difficult to obtain sufficient heat resistance in the cured product. Therefore, when an excess amount of an amino compound is charged in advance [the above (b)], it is preferably used as long as the effects of the present invention are not impaired. In order to effectively react at least two primary amino groups in an amino compound with a ketone group to form a C═N bond, the amino compound is synthesized from polyimide siloxane as in (a) or (c) above. It is preferable to add after completing (imidization). In the case of the above (c), the heat condensation can also be performed by, for example, a heat treatment after forming a composition in which an amino compound and polyimide siloxane are mixed on a support substrate.

[Metal layer]
Examples of the metal layer in the thermally conductive substrate of the present invention include conductive metal foils such as copper, aluminum, iron, silver, palladium, nickel, chromium, molybdenum, tungsten, zinc, and alloys thereof. Among them, copper foil or alloy copper foil or aluminum foil containing 90% or more of copper is preferably used. The preferred thickness range of the metal layer can be set according to the use of the thermally conductive substrate, but when used as a substrate material for electronic equipment, lighting equipment, etc., it is preferably in the range of 5 to 2000 μm, for example. If the thickness of the metal layer is less than 5 μm, problems such as wrinkles may occur during conveyance in the manufacturing process. Conversely, if the thickness exceeds 2000 μm, workability may be reduced.

Further, the conductive metal foil used as the metal layer has a surface roughness (Ra) of the surface to be bonded to the insulating layer of, for example, 0.05 in order to achieve both the adhesion to the insulating layer and the fine circuit processability. It is preferably in the range of -1.0 μm. If the surface roughness (Ra) of the surface that adheres to the insulating layer is less than 0.05 μm, the metal layer and the insulating layer may be easily peeled off depending on the use of the thermally conductive substrate, while the surface of the surface that adheres to the insulating layer. When the roughness (Ra) exceeds 1.0 μm, the adhesion between the metal layer and the insulating layer becomes good due to the anchor effect due to the roughening, but there is a concern that the wiring shape may deteriorate when the metal layer is processed by wiring. .

[Method for producing thermally conductive substrate]
Next, an example of a method for producing a heat conductive substrate (metal-clad laminate) will be described. Thermally conductive substrate is a polyimide-siloxane solution in which a thermally conductive filler is uniformly dispersed and a solution of a filler-containing polyimide resin in which an amino compound is mixed is directly applied onto a metal substrate to be a metal layer and then dried and applied. A filler-containing polyimide resin layer is formed by heating the coating film and reacting the amino group of the amino compound with at least a part of the ketone group in polyimidesiloxane to form a C = N bond. Can be manufactured by a method including. In this case, the filler-containing polyimide resin layer may be further laminated on the filler-containing polyimide resin layer by the same method, or another polyimide resin layer may be laminated. Here, as a metal base material, metal foils, such as above-mentioned copper foil used as the conductor layer of a thermal radiation board | substrate or a circuit board, can be used. In addition, as described above, the filler-containing polyimide resin layer may be in a cured state in which cross-linking is completed or in a semi-cured state in which cross-linking is not completed.

Application of the filler-containing polyimide resin solution on the metal substrate can be performed by a known method, for example, appropriately selected from a barcode method, a gravure coating method, a roll coating method, a die coating method, and the like. Can do.

In order to explain the present invention more clearly, a thermally conductive substrate (single-sided metal thermally conductive substrate) having a metal layer on one side of an insulating layer and a thermally conductive substrate (double-sided metal having a metal layer on both sides of the insulating layer) Production examples are shown separately for the thermally conductive substrate. Here, a case where the insulating layer is constituted by only one filler-containing polyimide resin layer will be described as an example.

<Single-sided metal thermal conductive substrate>
First, a metal foil such as a copper foil constituting the metal layer of the thermally conductive substrate is prepared. On this metal foil, a polyimide resin solution containing a thermally conductive filler and an amino compound is applied and dried at a temperature of 120 ° C. or less, for example, to remove a certain amount of solvent. Thereafter, it is further heat-treated at a high temperature to cause a crosslinking reaction with an amino compound. Thereby, it can be set as the heat conductive board | substrate which has a metal layer on the single side | surface of a filler containing polyimide resin layer. Here, the heat treatment time for forming a cross-link with the amino compound can be set according to the target cross-link formation rate. When a single-sided metal thermal conductive substrate is used as a resin-coated copper foil, the crosslink formation rate is lowered on the assumption that, for example, a metal foil, a ceramic substrate, or another material member will be bonded to the filler-containing polyimide resin layer later. Therefore, the heat treatment time in that case is preferably in the range of 3 to 60 minutes, for example, and more preferably in the range of 5 to 30 minutes in the above temperature range.

<Double-sided metal thermal conductive substrate>
The double-sided metal thermally conductive substrate can be produced by thermocompression bonding a metal foil to the filler-containing polyimide resin layer of the single-sided metal thermally conductive substrate obtained by the above method. The conditions for thermocompression bonding of the metal foil are preferably, for example, that the heating temperature is in the range of 120 to 180 ° C., the pressure is in the range of 2 to 4 MPa, and the pressing time is in the range of 0.1 to 24 hours.

In the thermally conductive substrate of the present embodiment, the content of the thermally conductive filler is adjusted to an appropriate range in addition to the crosslinked structure of the amino compound. As a result, the insulating layer has sufficient heat resistance, the metal layer and the insulating layer can be bonded at a relatively low temperature without interposing an adhesive layer, and has excellent thermal conductivity. Accordingly, the thermally conductive substrate of the present embodiment can be widely used industrially as a substrate material for electronic devices and lighting devices that require high heat dissipation, such as a heat dissipation substrate for power semiconductor mounting. It is particularly suitable for use in applications such as a heat dissipation board and a circuit board typified by a flexible board.

[Thermal conductive polyimide film]
The thermally conductive polyimide film of the present embodiment is a thermally conductive polyimide film provided with a filler-containing polyimide resin layer in which a thermally conductive filler is dispersed in a polyimide resin. The content of the heat conductive filler in the filler-containing polyimide resin layer is in the range of 5 to 80 wt%, and the polyimide resin in the filler-containing polyimide resin layer is represented by the above general formulas (1) and (2) The polyimide siloxane is an amino compound by reacting the ketone group in the polyimide siloxane having a unit with an amino group of an amino compound having at least two primary amino groups as functional groups to form a C = N bond. It has the structure bridge | crosslinked by. The polyimide resin may be in a cured state where the crosslinking reaction has been completed, or in a semi-cured state in which room for crosslinking is left. Here, the filler-containing polyimide resin layer has the same configuration as the filler-containing polyimide resin layer that constitutes a part or all of the insulating layer in the thermally conductive substrate. What was demonstrated in said heat conductive board | substrate can be used for the polyimide resin and heat conductive filler which comprise the filler containing polyimide resin layer of this Embodiment.

The entirety of the thermally conductive polyimide film of the present embodiment may be constituted by a filler-containing polyimide resin layer, and other than the filler-containing polyimide resin layer, other than the insulating layer of the thermally conductive substrate, Although the polyimide resin layer may be provided, it is preferable that the whole is formed of the filler-containing polyimide resin layer from the viewpoint of enhancing the heat dissipation characteristics. In this case, the filler-containing polyimide resin layer is not limited to a single layer, and may be a laminate of a plurality of layers. Thus, the thermally conductive polyimide film of the present embodiment has the same structure and physical properties as the insulating layer of the thermally conductive substrate, except that it is not bonded to the metal layer. And a heat conductive polyimide film is producible by removing the metal layer by etching, for example after producing the said heat conductive board | substrate. Alternatively, a coating solution in which an amino compound having a primary amino group is mixed with a polyimide resin solution after imidization containing a thermally conductive filler is applied to an arbitrary substrate, dried, and then peeled off from the substrate. It can also be set as a heat conductive polyimide film. In this case, it may be peeled off from the base material after it is heated on the base material to complete the crosslinking reaction, or it is peeled off from the base material in a state prior to curing just dried, and then heated to depend on the cross-linking reaction. Curing may be completed.

The thermally conductive polyimide film of the present embodiment has practical adhesive strength to metal foil (metal plate), ceramic substrate, Si substrate, etc., and is excellent in thermal conductivity. This thermally conductive polyimide film can be bonded to a metal foil (metal plate), a ceramic substrate, a Si substrate or the like without an adhesive layer. That is, the heat conductive polyimide film has a property that can be directly bonded to a bonding target base material such as a metal foil (metal plate) or a ceramic substrate on one or both sides without requiring an adhesive layer. Yes. Therefore, the thermally conductive polyimide film of the present embodiment is a film suitable for being used by being laminated on a base material such as a metal layer or a ceramic layer in applications such as a heat dissipation board or a circuit board.

Since other configurations and effects of the thermally conductive polyimide film of the present embodiment are the same as those of the insulating layer in the thermally conductive substrate, description thereof is omitted.

As described above, since the thermally conductive substrate and the thermally conductive polyimide film of the present embodiment include the filler-containing polyimide resin layer containing a specific polyimide resin in the insulating layer, thermocompression bonding at a relatively low temperature. In addition to being excellent in soldering heat resistance of the insulating layer, it is excellent in heat conduction characteristics without deteriorating the adhesive force with the metal wiring layer even when repeatedly placed in a high temperature environment. Therefore, by using the heat conductive substrate and the heat conductive polyimide film of the present embodiment, it is possible to improve the reliability of a circuit board, a heat dissipation board, a copper foil with a heat conductive resin, etc. used in a high temperature environment. it can.

Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these examples. In the following examples, various measurements and evaluations are as follows unless otherwise specified.

[Measurement of adhesive strength]
The adhesive strength was 10 mm in width and 100 mm in length, and the adhesive surface of the test piece was placed on a glossy surface of copper foil (thickness of 35 μm) (with rust-proof metal removed), temperature 160 ° C., pressure 2 MPa, After pressing for 2 hours, the tensile strength (strength-M1 manufactured by Toyo Seiki Co., Ltd.) is used to determine the force at the time of peeling at a speed of 50 mm / min in the 180 ° direction as the adhesive strength.

[Measurement of weight average molecular weight (Mw)]
The weight average molecular weight was measured by gel permeation chromatography (manufactured by Tosoh Corporation, using HLC-8220GPC). Polystyrene was used as a standard substance, and N, N-dimethylacetamide was used as a developing solvent.

[Evaluation method of warpage]
The warpage was evaluated by the following method. A polyimide adhesive was applied onto a 25 μm thick Kapton film so that the thickness after drying was 35 μm. In this state, the Kapton film was placed on the lower surface, and the average of the heights of warping of the four corners of the film was measured.

[Method for evaluating solder heat resistance (drying)]
A circuit of polyimide copper-clad laminate (manufactured by Nippon Steel Chemical Co., Ltd., trade name: Espanex MC18-25-00FRM) was formed, and a circuit with wiring width / wiring interval (L / S) = 1 mm / 1 mm was formed. A printed circuit board is prepared, and the adhesive surface of the test piece is placed on the wiring of the printed circuit board and pressed under conditions of a temperature of 170 ° C., a pressure of 1 MPa, and an hour of 1 minute, and then an oven at 150 ° C. for 24 hours Heated under conditions. This test piece with copper foil was left at 105 ° C. and 50% relative humidity for 1 hour, then immersed in a solder bath set to each evaluation temperature for 10 seconds, and observed for adhesion, foaming, blistering, and peeling. The presence or absence of such defects was confirmed. The heat resistance is expressed by an upper limit temperature at which no defect occurs. For example, “320 ° C.” means that no defect is recognized when evaluated in a solder bath at 320 ° C.

[Method for evaluating solder heat resistance (moisture resistance)]
A circuit of polyimide copper-clad laminate (manufactured by Nippon Steel Chemical Co., Ltd., trade name: Espanex MC18-25-00FRM) was formed, and a circuit with wiring width / wiring interval (L / S) = 1 mm / 1 mm was formed. A printed circuit board is prepared, and the adhesive surface of the test piece is placed on the wiring of the printed circuit board and pressed under conditions of a temperature of 170 ° C., a pressure of 1 MPa, and an hour of 1 minute, and then an oven at 150 ° C. for 24 hours Heated under conditions. The test piece with the copper foil was allowed to stand at 85 ° C. and a relative humidity of 85% for 24 hours, and then immersed in a solder bath set to each evaluation temperature for 10 seconds. The presence or absence of malfunctions was confirmed. The heat resistance is expressed by an upper limit temperature at which no defect occurs. For example, “270 ° C.” means that no defect is recognized when evaluated in a solder bath at 270 ° C.

[Rheometer evaluation]
A polyimide adhesive was applied onto the release PET film so that the thickness after drying was 25 μm. The polyimide adhesive film is peeled from the release PET film, about 10 polyimide adhesive films (3 cm × 3 cm) are laminated, and thermocompression bonding is performed using a vacuum laminator under the conditions of 70 ° C./0.85 MPa / 10 sec. A sample having a thickness of about 250 μm was prepared. About the obtained sample, the viscosity change of the sample was evaluated on the conditions of the temperature increase rate of 4 degree-C / min using the rheometer (RS150 RheoStress, the product made from Haake).

The abbreviations used in the examples represent the following compounds.
BTDA: 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride BPDA: 3,3 ′, 4,4′-diphenyltetracarboxylic dianhydride BAPP: 2,2-bis (4-aminophenoxy) Phenyl) propane BAFL: bisaniline fluorene PSX: diaminosiloxane (weight average molecular weight is 740)
N-12: dodecanedioic acid dihydrazide ADH: adipic acid dihydrazide K-1: talc (manufactured by Nippon Talc Co., Ltd., trade name; MICRO ACE K-1, shape: scaly, average major axis; 7.0 μm, average minor axis; 5.8 μm, ratio of major axis to thickness: 15 or more, average particle size: 6.6 μm, median diameter (D50); 6.9 μm, maximum particle size; 64.9 μm, minimum particle size: 0.5 μm, mode Diameter: 8.7 μm, cumulative particle amount of particle size of 10 μm or less; 77%, cumulative particle amount of particle size of 20 μm or more; 5%)

Synthesis Example 1-1
In a 1000 ml separable flask, 71.850 g PSX (0.0971 mol), 7.474 g BAPP (0.0182 mol), 1.568 g N-12 (0.0061 mol), 39.109 g BTDA. (0.1214 mol) 168 g of N-methyl-2-pyrrolidone and 112 g of xylene were charged and mixed well at room temperature for 1 hour to obtain a polyamic acid solution. This polyamic acid solution was heated to 190 ° C., heated and stirred for 20 hours to obtain a polyimide solution 1a having completed imidization. The weight average molecular weight (Mw) of the polyimide resin in the obtained polyimide solution 1a was 90,000. At this time, the mol% of the diaminosiloxane component relative to the total diamine component is 80% (m value = 0.8).

Synthesis Example 1-2
In a 1000 ml separable flask, 72.407 g PSX (0.0978 mol), 5.021 g BAPP (0.0122 mol), 3.160 g N-12 (0.0122 mol), 39.412 g BTDA (0.1223 mol) 168 g of N-methyl-2-pyrrolidone and 112 g of xylene were charged and mixed well at room temperature for 1 hour to obtain a polyamic acid solution. This polyamic acid solution was heated to 190 ° C., heated and stirred for 20 hours to obtain a polyimide solution 1b having completed imidization. The weight average molecular weight (Mw) of the polyimide resin in the obtained polyimide solution 1b was 73,000. At this time, the mol% of the diaminosiloxane component relative to the total diamine component is 80% (m value = 0.8).

Synthesis Example 1-3
In a 1000 ml separable flask, 71.301 g PSX (0.0964 mol), 9.889 g BAPP (0.0241 mol), 38.810 g BTDA (0.1204 mol), 168 g N-methyl-2 -Pyrrolidone and 112 g of xylene were charged and mixed well at room temperature for 1 hour to obtain a polyamic acid solution. This polyamic acid solution was heated to 190 ° C., heated and stirred for 6 hours to obtain a polyimide solution 1c having completed imidization. The weight average molecular weight (Mw) of the polyimide resin in the obtained polyimide solution 1c was 107,000. At this time, the mol% of the diaminosiloxane component relative to the total diamine component is 80% (m value = 0.8).

Synthesis examples 1-1 to 1-3 are summarized in Table 1.

Reference Example 1-1
The polyimide solution 1a obtained in Synthesis Example 1-1 was applied to one surface of a polyimide film (manufactured by DuPont, trade name: Kapton ENS, length × width × thickness = 200 mm × 300 mm × 25 μm), and 15 minutes at 80 ° C. Drying was performed to obtain a coverlay film having an adhesive layer thickness of 35 μm. Next, the obtained coverlay film was placed on a copper foil from which the surface rust-proof metal layer was removed, and pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours to obtain an evaluation sample.

[Example 1-1]
The polyimide solution 1a obtained in Synthesis Example 1-1 was mixed with 5.78 g of N-12 (0.0224 mol) and 57.81 g of K-1 and further stirred for 1 hour to obtain a polyimide solution 1. It was.

The obtained polyimide solution 1 was applied to one side of a polyimide film (manufactured by DuPont, trade name: Kapton ENS, length × width × thickness = 200 mm × 300 mm × 25 μm), dried at 80 ° C. for 15 minutes, and adhesive A coverlay film 1 having a layer thickness of 35 μm was obtained. This cover lay film 1 was placed on a copper foil from which the rust-proof metal layer on the surface was removed, and pressed under the conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours to obtain Evaluation Sample 1. The adhesive strength with the copper foil after curing was 0.65 kN / m. Moreover, the warp of the coverlay film was no problem. Moreover, the polyimide solution 1 was apply | coated to the single side | surface of a base material, and it dried for 15 minutes at 80 degreeC, and produced the 25-micrometer-thick polyimide adhesive film. About 10 sheets of this polyimide adhesive film were thermocompression-bonded with a vacuum laminator under conditions of a temperature of 70 ° C., a pressure of 0.85 MPa, and a time of 10 sec, and a sample having a thickness of about 250 μm was prepared. The viscosity at 11 ° C. was 118,000 Pa · s.

Next, heat treatment was performed on the evaluation sample 1 in an oven in the atmosphere at 150 ° C. for 1000 hours. It was 0.45 kN / m when the copper foil after a process and the adhesive strength of a coverlay film were measured. The peeling surface at this time was an interface between copper and the adhesive layer.

Further, a printed circuit board having a circuit {wiring width / wiring interval (L / S) = 25 μm / 25 μm} formed of copper on both sides of the polyimide film was prepared, and the coverlay film 1 obtained in Example 1-1 was prepared. The printed circuit board was placed on the circuit surface and pressed under the conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours to obtain a wiring board 1 provided with a coverlay film.

[Example 1-2]
After obtaining polyimide solution 2 in the same manner as in Example 1-1 except that 57.81 g of K-1 in Example 1-1 was blended, K-1 was not blended. The coverlay film 2 was obtained and the evaluation sample 2 was obtained. When the Raman spectrum of the adhesive layer in the evaluation sample was measured, a peak due to the formation of an imino group was confirmed in the vicinity of 1567 cm ⁻¹ . From this measurement result, it is presumed that in the evaluation sample, the condensation reaction between the ketone group in the polyimide resin and the amino compound (N-12) occurred simultaneously with the thermocompression bonding of the coverlay film and the copper foil. The adhesive strength with the copper foil after curing was 1.08 kN / m. Moreover, the warp of the coverlay film was no problem. The rheometer evaluation of the polyimide adhesive film produced in the same manner as in Example 1-1 using the polyimide solution 2 revealed that the viscosity at 260 ° C. was 113,000 Pa · s.

Next, heat treatment was performed on the evaluation sample 2 in an oven in the atmosphere at 150 ° C. for 1000 hours. It was 0.41 kN / m when the copper foil after a process and the adhesive strength of a coverlay film were measured. The peeling surface at this time was an interface between copper and the adhesive layer.

Further, a printed circuit board on which a circuit {wiring width / wiring interval (L / S) = 25 μm / 25 μm} is prepared in the same manner as in Example 1-1, and the coverlay obtained in Example 1-2 is prepared. The film 2 was placed on the circuit surface of the printed board and thermocompression bonded to obtain a wiring board 2 provided with a coverlay film.

[Example 1-3]
The same procedure as in Example 1-1 except that 3.47 g of N-12 (0.0134 mol) was blended instead of blending 5.78 g of N-12 in Example 1-1. After obtaining the polyimide solution 3, the coverlay film 3 was obtained and the evaluation sample 3 was obtained. The adhesive strength with the copper foil after curing was 0.70 kN / m. Moreover, the warp of the coverlay film was no problem. The rheometer evaluation of the polyimide adhesive film produced in the same manner as in Example 1-1 using the polyimide solution 3 revealed that the viscosity at 260 ° C. was 35,000 Pa · s.

Next, heat treatment was performed on the evaluation sample 3 in an oven in the atmosphere at 150 ° C. for 1000 hours. It was 0.39 kN / m when the copper foil after a process and the adhesive strength of a coverlay film were measured. The peeling surface at this time was an interface between copper and the adhesive layer.

Further, a printed circuit board on which a circuit {wiring width / wiring interval (L / S) = 25 μm / 25 μm} is prepared in the same manner as in Example 1-1, and the coverlay obtained in Example 1-3 is prepared. The film 3 was placed on the circuit surface of the printed board and thermocompression bonded to obtain a wiring board 3 provided with a coverlay film.

[Example 1-4]
After obtaining the polyimide solution 4 in the same manner as in Example 1-1, except that the polyimide solution 1b obtained in Synthesis Example 1-2 was used instead of the polyimide solution 1a in Example 1-1, A coverlay film 4 was obtained, and an evaluation sample 4 was obtained. The adhesive strength with the cured copper foil was 0.72 kN / m. Moreover, the warp of the coverlay film was no problem. The rheometer evaluation of the polyimide adhesive film produced in the same manner as in Example 1-1 using the polyimide solution 4 revealed that the viscosity at 260 ° C. was 110,000 Pa · s.

Next, the evaluation sample 4 was heat-treated in the oven at 150 ° C. for 1000 hours in the atmosphere. It was 0.58 kN / m when the copper foil after a process and the adhesive strength of the coverlay film were measured. The peeling surface at this time was an interface between copper and the adhesive layer.

Further, a printed circuit board on which a circuit {wiring width / wiring interval (L / S) = 25 μm / 25 μm} was prepared in the same manner as in Example 1-1, and the coverlay obtained in Example 1-4 was prepared. The film 4 was placed on the circuit surface of the printed board and thermocompression bonded to obtain a wiring board 4 provided with a coverlay film.

[Example 1-5]
Instead of the polyimide solution 1a in Example 1-1, the polyimide solution 1b obtained in Synthesis Example 1-2 was used, and instead of 5.78 g of N-12 blended, 3.47 g of Except that N-12 (0.0134 mol) was blended, a polyimide solution 5 was obtained in the same manner as in Example 1-1, then a coverlay film 5 was obtained, and an evaluation sample 5 was obtained. The adhesive strength with the copper foil after curing was 0.80 kN / m. Moreover, the warp of the coverlay film was no problem. The rheometer evaluation of the polyimide adhesive film produced in the same manner as in Example 1-1 using the polyimide solution 5 revealed that the viscosity at 260 ° C. was 108,000 Pa · s.

Next, heat treatment was performed on the evaluation sample 5 in an oven in the atmosphere at 150 ° C. for 1000 hours. It was 0.48 kN / m when the copper foil after a process and the adhesive strength of a coverlay film were measured. The peeling surface at this time was an interface between copper and the adhesive layer.

Further, a printed circuit board on which a circuit {wiring width / wiring interval (L / S) = 25 μm / 25 μm} is prepared in the same manner as in Example 1-1, and the coverlay obtained in Example 1-5 is prepared. The film 5 was placed on the circuit surface of the printed board and thermocompression bonded to obtain a wiring board 5 provided with a coverlay film.

[Example 1-6]
A polyimide was prepared in the same manner as in Example 1-1 except that 5.78 g of BAPP (0.0141 mol) was added instead of 5.78 g of N-12 in Example 1-1. After obtaining the solution 6, the coverlay film 6 was obtained and the evaluation sample 6 was obtained. The adhesive strength with the cured copper foil was 0.72 kN / m. Moreover, the warp of the coverlay film was no problem. The rheometer evaluation of the polyimide adhesive film produced in the same manner as in Example 1-1 using the polyimide solution 6 revealed that the viscosity at 260 ° C. was 36,000 Pa · s.

Next, the evaluation sample 6 was heat-treated in an oven at 150 ° C. for 1000 hours in the atmosphere. It was 0.51 kN / m when the copper foil after a process and the adhesive strength of a coverlay film were measured. The peeling surface at this time was an interface between copper and the adhesive layer.

Further, a printed circuit board on which a circuit {wiring width / wiring interval (L / S) = 25 μm / 25 μm} is prepared in the same manner as in Example 1-1, and the coverlay obtained in Example 1-6 is prepared. The film 6 was placed on the circuit surface of the printed board and thermocompression bonded to obtain a wiring board 6 provided with a coverlay film.

[Example 1-7]
A polyimide was prepared in the same manner as in Example 1-1 except that 5.78 g of BAFL (0.0166 mol) was added instead of 5.78 g of N-12 in Example 1-1. After obtaining the solution 7, the coverlay film 7 was obtained and the evaluation sample 7 was obtained. The adhesive strength with the cured copper foil was 0.65 kN / m. Moreover, the warp of the coverlay film was no problem. The rheometer evaluation of the polyimide adhesive film produced in the same manner as in Example 1-1 using the polyimide solution 7 revealed that the viscosity at 260 ° C. was 28,000 Pa · s.

Next, heat treatment was performed on the evaluation sample 7 in an oven in the air at 150 ° C. for 1000 hours. It was 0.41 kN / m when the copper foil after a process and the adhesive strength of a coverlay film were measured. The peeling surface at this time was an interface between copper and the adhesive layer.

Further, a printed circuit board on which a circuit {wiring width / wiring interval (L / S) = 25 μm / 25 μm} is prepared in the same manner as in Example 1-1, and the coverlay obtained in Example 1-7 is prepared. The film 7 was placed on the circuit surface of the printed board and thermocompression bonded to obtain a wiring board 7 provided with a coverlay film.

Reference Example 1-2
A polyimide solution was obtained in the same manner as in Example 1-1 except that the polyimide solution 1c obtained in Synthesis Example 1-3 was used instead of the polyimide solution 1a in Example 1-1. This polyimide solution is applied to one side of a polyimide film (DuPont, trade name: Kapton ENS, length x width x thickness = 200 mm x 300 mm x 25 µm), dried at 80 ° C for 15 minutes, and the thickness of the adhesive layer A 35 μm coverlay film was obtained. The coverlay film was evaluated in the same manner as in Example 1-1.

The results of Examples 1-1 to 1-7 and Reference Examples 1-1 to 1-2 are collectively shown in Table 2 and Table 3. In Table 2 and Table 3, adhesive strength 1 indicates the adhesive strength between the cured copper foil and coverlay film, and adhesive strength 2 indicates the copper foil and coverlay film after heat treatment in air at 150 ° C. for 1000 hours. The adhesive strength is shown. In addition, the molar ratio in Table 2 and Table 3 means the molar ratio of the sum total of the primary amino group in an amino compound with respect to 1 mol of ketone groups in a polyimidesiloxane.

[Verification of the effect of shortening the time for imine bridge formation by introducing hydrogen bond-forming groups]
The shortening of the imine crosslink formation time of the adhesive resin composition according to the present invention was verified as follows.

[Example 1-8]
The polyimide solution 1a obtained in Synthesis Example 1-1 was mixed with 5.78 g of N-12 (0.224 mol) and 11.56 g of K-1 and further stirred for 1 hour to obtain a polyimide solution 8. It was.

The obtained polyimide solution 8 was applied to one side of a polyimide film (manufactured by DuPont, trade name: Kapton ENS, length × width × thickness = 200 mm × 300 mm × 25 μm), dried at 80 ° C. for 15 minutes, and adhesive A coverlay film 8 having a layer thickness of 35 μm was obtained. This cover lay film 8 was placed on a copper foil from which the surface rust-proof metal layer was removed, and pressed under the conditions of a temperature of 200 ° C., a pressure of 2 MPa, and a time of 1 hour to obtain an evaluation sample 8. The evaluation results are shown in Table 4.

[Example 1-9]
In the same manner as in Example 1-8, a polyimide solution 8 was obtained, and then a coverlay film 8 was obtained.

Example 1-8 was used except that heating was performed under the conditions of a temperature of 150 ° C., a pressure of 2 MPa, and an hour of 1 hour instead of heating under the conditions of a temperature of 200 ° C., a pressure of 2 MPa, and an hour of 1 hour. In the same manner as described above, an evaluation sample 9 was obtained. The evaluation results are shown in Table 4.

[Example 1-10]
Example 1 is the same as Example 1-8 except that heating was performed under the conditions of a temperature of 200 ° C., a pressure of 2 MPa, and a time of 1 hour, except that heating was performed under the conditions of a temperature of 200 ° C., a pressure of 2 MPa, and a time of 0.5 hours. In the same manner as in −8, an evaluation sample 10 was obtained. The evaluation results are shown in Table 4.

[Example 1-11]
Example 1-8 except that heating was performed under conditions of a temperature of 200 ° C., a pressure of 2 MPa, and a time of 1 hour, except that heating was performed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 0.5 hours. In the same manner as in −8, an evaluation sample 11 was obtained. The evaluation results are shown in Table 4.

[Example 1-12]
Example 1-8 was used except that heating was performed under the conditions of a temperature of 200 ° C., a pressure of 2 MPa, and an hour of 1 hour instead of heating under the conditions of a temperature of 200 ° C., a pressure of 2 MPa, and an hour of 1 hour in Example 1-8. In the same manner as described above, an evaluation sample 12 was obtained. The evaluation results are shown in Table 4.

The results of Example 1-8 to Example 1-12 are summarized in Table 4.

From Table 4, by introducing hydrogen bond-forming groups into polyimidesiloxane, practically sufficient solder heat resistance (especially moisture solder heat resistance) can be obtained by heating at a temperature of 150 ° C. to 200 ° C. for 0.5 to 1 hour. It was confirmed that

[Test Example 1]
The polyimide solution 1 prepared in Example 1-1 was applied to one side of a substrate and dried at 80 ° C. for 15 minutes to produce a polyimide adhesive film having a thickness of 25 μm. About 10 sheets of this polyimide adhesive film (3 cm × 3 cm) were laminated and thermocompression bonded under the conditions of 70 ° C./0.85 MPa / 10 sec using a vacuum laminator to obtain an evaluation sample A having a thickness of about 250 μm. . On the other hand, the polyimide solution prepared in Reference Example 1-2 was treated in the same manner to obtain Evaluation Sample B. A rheometer evaluation was performed on these samples A and B. The results are shown in FIG. The viscosity of sample A rapidly increased from around 160 ° C., and the viscosity at around 260 ° C. was 118,000 Pa · s. On the other hand, the increase in viscosity of Sample B was slower than that of Sample A, and the viscosity at around 260 ° C. was 45,000 Pa · s. The difference in the rate of increase in the viscosity of Samples A and B is that polyimide siloxane containing —NHCO— groups is different from Sample B using polyimide siloxane that does not contain —NHCO— groups, which are hydrogen bonding functional groups. It was considered that this was because the cross-linking reaction proceeded more rapidly in the sample A used. Here, in the comparison of solder heat resistance between Example 1-1 and Reference Example 1-2 shown in Table 2 and Table 3, Example 1-1 is much superior in terms of moisture solder resistance. I understand. Moreover, from FIG. 1, the viscosity of the sample A is almost flat at 1 × 10 ⁵ Pa · s or more at 200 ° C. or more. From these facts, the viscosity in the vicinity of 260 ° C. being 1 × 10 ⁵ Pa · s or more is a practically sufficient moisture-resistant solder heat resistance, that is, the ratio of crosslinking to obtain a solder heat-resistant temperature of 260 ° C. or more. It was thought that it was effective as a threshold value indicating

[Test Example 2]
The moisture resistance soldering heat resistance test was conducted by changing the molecular weight of the polyimidesiloxane used in Example 1-1. A coverlay film was prepared and evaluated for resistance to moisture soldering in the same manner as in Example 1-1 except that polyimidesiloxane having a different weight average molecular weight was used. The evaluation results are shown in Table 5. When polyimidesiloxane having a weight average molecular weight of about 88,000 to 130,000 was used, the resistance to moisture soldering was 260 ° C. or higher.

Next, rheometer evaluation was carried out by changing the molecular weight of the polyimidesiloxane used in Example 1-1, and a test for increasing viscosity was conducted. A polyimide solution was obtained in the same manner as in Example 1-1 except that polyimidesiloxane having a weight average molecular weight of 130,000 was used. This polyimide solution was applied to one side of the substrate and dried at 80 ° C. for 15 minutes to prepare a polyimide adhesive film having a thickness of 25 μm. About 10 sheets of this polyimide adhesive film (3 cm × 3 cm) were laminated and thermocompression bonded under the conditions of 70 ° C./0.85 MPa / 10 sec using a vacuum laminator to obtain an evaluation sample C having a thickness of about 250 μm. . Sample D was also prepared in the same manner as described above from a polyimide solution obtained in the same manner as in Example 1-1 except that polyimidesiloxane having a weight average molecular weight of 67,000 was used.

The results of rheometer evaluation for these samples C and D are shown in FIG. As shown in FIG. 2, the sample C having a weight average molecular weight of 130,000 has a temperature at which the viscosity starts to increase (curing start temperature) slightly higher than that of the sample D having a weight average molecular weight of 67,000 and exceeds 200 ° C. Viscosity was approximately 1 × 10 ⁵ Pa · s or more, whereas in Sample D, the temperature at which the viscosity began to rise was low and did not exceed 1 × 10 ⁵ Pa · s.

From the results shown in FIG. 2 and Table 2 above, it is necessary to consider the weight average molecular weight of polyimide siloxane in order to obtain practically sufficient moisture-resistant solder heat resistance. It was strongly suggested that an appropriate molecular weight range exists. Furthermore, considering the threshold value obtained in Test Example 1, it was considered that the weight average molecular weight of the polyimidesiloxane is preferably in the range of 70,000 to 140,000. Although the reason why such a molecular weight range is preferable for obtaining practically sufficient moisture-resistant soldering heat resistance has not yet been elucidated, a rational explanation can be made by considering the following. That is, the lower the molecular weight of polyimide siloxane, the higher the crosslinking reactivity, but at an excessively low molecular weight below 70,000, the viscosity at 260 ° C. does not reach the threshold value and the resistance to moisture solder resistance Is considered to decrease. Conversely, if the molecular weight of the polyimide siloxane is higher than 140,000, the mobility of the polyimide molecular chain is lowered and the crosslinking reactivity is lowered. In this case, too, the viscosity at 260 ° C. does not reach the threshold value. Conceivable.

Next, examples of the heat conductive substrate and the heat conductive polyimide film will be described. In the following examples, various measurements and evaluations are as follows unless otherwise specified.

[Copper foil peel strength (peel strength)]
The copper foil layer of the heat conductive substrate was pattern-etched into a long rectangle with a width of 1.0 mm and a length of 180 mm, and a test piece was cut out to a width of 20 mm and a length of 200 mm so that the pattern would be in the center, and IPC-TM- A 180 ° peeling test was conducted by 650.2.19 (manufactured by Toyo Seiki).

[Thickness direction thermal conductivity (λzTC)]
A thermally conductive polyimide film was cut into a size of 20 mm × 20 mm, subjected to vapor deposition with platinum and blackening treatment, and then a thermal diffusivity in the thickness direction by a laser flash method (Xenon Flash Analyzer LFA 447 Nanoflash manufactured by NETZSCH), according to DSC The specific heat and the density by the underwater substitution method were measured, and the thermal conductivity (W / m · K) was calculated based on these results. In addition, the heat conductive polyimide film produced and used the sample of thickness 100 micrometers at the time of a measurement.

[Withstand voltage]
The thermally conductive polyimide film was cut into a size of 5 cm × 5 cm, and the withstand voltage was measured in insulating oil by a step-up method using a TOS 5101 apparatus manufactured by KIKUSUI based on JIS C2110. The voltage was stepped up in steps of 0.2 kV, held at each voltage for 20 seconds, a leakage current of 8.5 mA, and the value immediately before the broken voltage was the initial withstand voltage. The size of the electrode is 2 cmφ.

[Method for evaluating solder heat resistance (drying)]
Circuit processing is carried out by patterning the copper foil layer of the heat conductive substrate into a predetermined shape, dipping in a solder bath at each temperature up to 300 ° C. for 10 seconds, observing the adhesive state, foaming, blistering, peeling, etc. The presence or absence of defects was confirmed. For the heat resistance, the upper limit temperature at which no defects occur was defined as solder heat resistance. For example, “300 ° C.” means that no defect is observed when evaluated in a solder bath at 300 ° C.

[Curl measurement method]
CCL curl (maximum warpage):
Cut the metal / resin laminate into a size of 50 mm x 50 mm, leave it for 24 hours in a constant temperature and humidity environment (23 ± 3 ° C, 50 ± 5% RH), and then measure the amount of warping at the four corners using a caliper. Carried out. At this time, when warping toward the resin surface side or the metal side, the CCL maximum warpage amount was determined at the place with the largest warpage amount. The case where the absolute amount of the maximum warp amount was 5 mm or less was judged as ◯ (good), and the case where it was 5 mm or more was judged as x (defective).

The abbreviations used in the examples represent the following compounds.
BTDA: 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride BPDA: 3,3 ′, 4,4′-diphenyltetracarboxylic dianhydride BAPP: 2,2-bis (4-aminophenoxy) Phenyl) propane DAPE: 4,4′-diaminodiphenyl ether m-TB: 2,2′-dimethyl-4,4′-diaminobiphenyl

PSX: diaminosiloxane represented by the following general formula (the number average value of m ₁ is in the range of 1 to 20 and the weight average molecular weight is 740)

N-12: Dodecanedioic acid dihydrazide having the following structural formula

NMP: N-methyl-2-pyrrolidone DMAc: N, N-dimethylacetamide

Synthesis Example 2-1
In a 1000 ml separable flask, 71.850 g PSX (0.0971 mol), 7.474 g BAPP (0.0182 mol), 1.568 g N-12 (0.0061 mol), 39.109 g BTDA. (0.1214 mol) 168 g of N-methyl-2-pyrrolidone and 112 g of xylene were charged and mixed well at room temperature for 1 hour to obtain a polyamic acid solution. This polyamic acid solution was heated to 190 ° C., heated and stirred for 20 hours to obtain a polyimide solution 2a having completed imidization. The weight average molecular weight (Mw) of the polyimide resin in the obtained polyimide solution 2a was 90,000. At this time, the mol% of the diaminosiloxane component relative to the total diamine component is 80%.

[Example 2-1]
63.88 g of the polyimide solution 2a obtained in Synthesis Example 2-1 was weighed, and 2.56 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added. Mix with a centrifugal stirrer until uniform. Subsequently, 38.4 g of solvent NMP was weighed into another container, 1.096 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the above-mentioned polyimide solution containing alumina and mixed again with a centrifugal stirrer until uniform, to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied onto a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating at 80 ° C. for 30 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 60 minutes to form an insulating layer in which a heat conductive filler is dispersed in polyimide resin on the rolled copper foil, and heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina as a heat conductive filler in this insulating layer is 10 wt%. Subsequently, a rolled copper foil having a thickness of 18 μm is placed on the polyimide insulating layer of the thermally conductive substrate, pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours, and the thermal conductivity having a metal layer on both sides. A substrate was obtained.

In order to evaluate the characteristics of the insulating layer in the obtained thermally conductive substrate, the copper foil was removed by etching to produce a thermally conductive polyimide film (F1), and the withstand voltage and thermal conductivity were evaluated. These results are shown in Table 6. Further, the heat conductive substrate was processed into a predetermined pattern, and the adhesive strength, solder heat resistance and curl were measured. These results are shown in Table 7. “Applied surface adhesive strength” in Table 7 means the adhesive strength between the coating film and the metal layer at the boundary between the copper foil when the polyimide solution is applied onto the rolled copper foil, “Adhesion strength” means the adhesion strength when the metal layer is later pressure-bonded to the surface side of the coating film when the polyimide solution is applied onto the rolled copper foil (the same applies in Table 9).

[Example 2-2]
47.99 g of the polyimide solution 2a obtained in Synthesis Example 2-1 was weighed, and 17.28 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added. Mix with a centrifugal stirrer until uniform. Subsequently, 28.81 g of solvent NMP was weighed into another container, 0.82 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the above-mentioned polyimide solution containing alumina and mixed with a centrifugal stirrer until it became uniform again to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied onto a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating at 80 ° C. for 30 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 60 minutes to form an insulating layer in which a heat conductive filler is dispersed in polyimide resin on the rolled copper foil, and heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina which is a heat conductive filler in this insulating layer is 50 wt%. Subsequently, a rolled copper foil having a thickness of 18 μm is placed on the polyimide insulating layer of the thermally conductive substrate, pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours, and the thermal conductivity having a metal layer on both sides. A substrate was obtained. Subsequently, evaluation was performed in the same manner as in Example 2-1. The results are shown in Tables 6 and 7.

[Example 2-3]
47.88 g of the polyimide solution 2a obtained in Synthesis Example 2-1 was weighed, 17.24 g of aluminum nitride (average particle size 1.1 μm, manufactured by Tokuyama) was added, and mixed with a centrifugal stirrer until uniform. . Subsequently, 15.6 g of solvent NMP was weighed in another container, 0.82 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the polyimide solution containing the above aluminum nitride, and mixed again with a centrifugal stirrer until uniform, to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied onto a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating at 80 ° C. for 30 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 60 minutes to form an insulating layer in which a heat conductive filler is dispersed in polyimide resin on the rolled copper foil, and heat conduction having a metal layer on one side. A conductive substrate was produced. The content of aluminum nitride which is a heat conductive filler in this insulating layer is 50 wt%. Subsequently, a rolled copper foil having a thickness of 18 μm is placed on the polyimide insulating layer of the thermally conductive substrate, pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours, and the thermal conductivity having a metal layer on both sides. A substrate was obtained. Subsequently, evaluation was performed in the same manner as in Example 2-1. The results are shown in Tables 6 and 7.

Synthesis Example 2-2
In a 1000 ml separable flask, 71.30 g PSX (0.0964 mol), 9.89 g BAPP (0.0241 mol), 38.66 g BTDA (0.120 mol), 168 g N-methyl-2 -Pyrrolidone and 112 g of xylene were charged and mixed well at room temperature for 1 hour to obtain a polyamic acid solution. This polyamic acid solution was heated to 190 ° C., heated and stirred for 20 hours to obtain a polyimide solution 2b having completed imidization. The weight average molecular weight (Mw) of the polyimide resin in the obtained polyimide solution 2b was 122,000. At this time, the mol% of the diaminosiloxane component relative to the total diamine component is 80% (m value = 0.8). In addition, "m value" means the presence molar ratio of the structural unit represented by the said General formula (1) contained in the obtained polyimide resin.

[Example 2-4]
400.24 g of the polyimide solution 2b obtained in Synthesis Example 2-2 was weighed, and 16.34 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added. Mix with a centrifugal stirrer until uniform. Subsequently, 97.4 g of solvent NMP was weighed into another container, 4.2 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the above polyimide solution containing alumina and mixed again with a centrifugal stirrer until uniform, to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied onto a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating at 80 ° C. for 30 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 2 hours to form an insulating layer in which a heat conductive filler is dispersed in polyimide resin on the rolled copper foil, and a heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina as a heat conductive filler in this insulating layer is 10 wt%. Subsequently, a rolled copper foil having a thickness of 18 μm is placed on the polyimide insulating layer of the thermally conductive substrate, pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours, and the thermal conductivity having a metal layer on both sides. A substrate was obtained. Subsequently, evaluation was performed in the same manner as in Example 2-1. The results are shown in Tables 6 and 7.

[Example 2-5]
400 g of the polyimide solution 2b obtained in Synthesis Example 2-2 was weighed, and 147.0 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added uniformly. It mixed with the centrifugal stirrer until it became. Subsequently, 97.3 g of solvent NMP was weighed into another container, 4.2 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the above polyimide solution containing alumina and mixed again with a centrifugal stirrer until uniform, to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied onto a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating at 80 ° C. for 30 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 2 hours to form an insulating layer in which a heat conductive filler is dispersed in polyimide resin on the rolled copper foil, and a heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina which is a heat conductive filler in this insulating layer is 50 wt%. Subsequently, a rolled copper foil having a thickness of 18 μm is placed on the polyimide insulating layer of the thermally conductive substrate, pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours, and the thermal conductivity having a metal layer on both sides. A substrate was obtained. Subsequently, evaluation was performed in the same manner as in Example 2-1. The results are shown in Tables 6 and 7.

Synthesis Example 2-3
To 255 g of DMAc in a 500 ml separable flask equipped with a stirrer, 28.9050 g of BAPP was added with stirring under a nitrogen stream and dissolved, and then 15.0281 g of PMDA was added while maintaining stirring. After 10 minutes, 1.0669 g of BPDA was added. Thereafter, the polymerization reaction was continued for 4 hours at room temperature to obtain a viscous polyamic acid solution 2c to be a polyimide precursor.

[Comparative Example 2-1]
78.7 g of the polyamic acid solution 2c obtained in Synthesis Example 2-3 was weighed, and 1.3 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added. The mixture was mixed with a centrifugal stirrer until uniform. Subsequently, 15.7 g of the solvent DMAc was added and mixed with a centrifugal stirrer until it became uniform again to obtain a polyamic acid solution containing 10 wt% of a heat conductive filler. Next, this polyamic acid solution was applied onto a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and dried by heating at 120 ° C. to remove the solvent. Thereafter, the temperature was raised and heated stepwise in a temperature range of 130 to 340 ° C. over 20 minutes to produce a thermally conductive substrate having a metal layer on one side. Subsequently, a rolled copper foil having a thickness of 18 μm was superposed on the polyimide insulating layer of this thermally conductive substrate, and thermocompression bonding was attempted at 160 ° C. using a vacuum press. However, since it could not be bonded at 160 ° C., it was heated at 160 ° C. and 270 ° C. for 30 minutes, then heated to a temperature of 360 ° C. at a surface pressure of 19.1 MPa, and subjected to thermocompression bonding under a press time of 25 minutes. A thermally conductive substrate having metal layers on both sides was obtained. Subsequently, evaluation was performed in the same manner as in Example 2-1. The results are shown in Tables 6 and 7.

[Comparative Example 2-2]
69.6 g of the polyamic acid solution 2c obtained in Synthesis Example 2-3 was weighed, and 10.4 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added. The mixture was mixed with a centrifugal stirrer until uniform. Subsequently, 13.9 g of the solvent DMAc was added and mixed with a centrifugal stirrer until it became uniform again to obtain a polyamic acid solution containing 50 wt% of the heat conductive filler. Next, a heat conductive substrate was obtained by operating in the same manner as in Comparative Example 2-1. Subsequently, evaluation was performed in the same manner as in Example 2-1. The results are shown in Tables 6 and 7.

[Synthesis Example 2-4]
20.7283 g of m-TB was added to 255 g of DMAc in a 500 ml separable flask equipped with a stirrer while stirring under a nitrogen stream, and then 11.5380 g of PMDA was added while maintaining stirring. In addition, after 10 minutes, 12.7337 g of BPDA was added. Thereafter, the polymerization reaction was continued for 4 hours at room temperature to obtain a viscous solution of the polyamic acid solution 2d serving as a polyimide precursor.

[Comparative Example 2-3]
Using the polyamic acid solution 2d obtained in Synthesis Example 2-4 in place of the polyamic acid solution 2c of Comparative Example 2-1, an operation similar to that of Comparative Example 2-1 was performed and thermocompression bonding was attempted. Accordingly, the heat-pressure bonding was performed with the press temperature of 360 ° C. in Comparative Example 2-1 set to 380 ° C., and the heat conductive substrate of Comparative Example 2-3 was obtained. Subsequently, evaluation was performed in the same manner as in Example 2-1. The results are shown in Tables 6 and 7.

[Comparative Example 2-4]
Although the polyamic acid solution 2d obtained in Synthesis Example 2-4 was used in place of the polyamic acid solution 2c of Comparative Example 2-2 and an operation similar to Comparative Example 2-2 was performed, thermocompression bonding was attempted. Therefore, the heat-pressure bonding was carried out with the press temperature of 360 ° C. in Comparative Example 2-1 set to 380 ° C., and the heat conductive substrate of Comparative Example 2-4 was obtained. Subsequently, evaluation was performed in the same manner as in Example 2-1. The results are shown in Tables 6 and 7.

[Comparative Example 2-5]
A double-sided metal laminate of Comparative Example 2-5 was obtained in the same manner as in Example 2-1, except that the alumina of Example 2-1 was not added. Subsequently, evaluation was performed in the same manner as in Example 2-1. The results are shown in Tables 6 and 7.

In Table 6, the content of the curing agent means the weight percent with respect to the solid content of the polyimide resin, and the filler content means the weight percent of the filler with respect to the entire thermally conductive polyimide film from which the copper foil has been removed by etching.

From Table 6, the heat conductive substrates of Examples 2-1 to 2-5 containing the heat conductive filler in the polyimide resin forming the insulating layer are formed of the polyimide resin not containing the heat conductive filler. It can be seen that the thermal conductivity is greatly improved as compared with the metal-clad laminate of Comparative Example 2-5. Further, from Table 7, the thermally conductive polyimide films of Examples 2-1 to 2-5 using a polyimide resin having a structure in which polyimidesiloxane is crosslinked with an amino compound are polyimide resins having no crosslinked structure. The press workability was better than the heat conductive polyimide films of Comparative Examples 2-1 to 2-4, and practically sufficient adhesiveness was obtained by pressing at a low temperature. In terms of voltage resistance and heat resistance, Examples 2-1 to 2-5 and Comparative Examples 2-1 to 2-5 had practically sufficient characteristics. The thermally conductive substrates of Examples 2-1 to 2-5 were small in curling and excellent in usability.

[Example 2-6]
63.89 g of the polyimide solution 2a obtained in Synthesis Example 2-1 was weighed, and 86.56 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added. Mix with a centrifugal stirrer until uniform. Subsequently, 35.06 g of solvent NMP was weighed in another container, 1.096 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the above-mentioned polyimide solution containing alumina and mixed again with a centrifugal stirrer until uniform, to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied on a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating at 80 ° C. for 15 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 60 minutes to form an insulating layer in which a heat conductive filler is dispersed in polyimide resin on the rolled copper foil, and heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina which is a heat conductive filler in this insulating layer is 79 wt%.

In order to evaluate the characteristics of the insulating layer in the obtained thermally conductive substrate, the copper foil was removed by etching to produce a thermally conductive polyimide film (F6), and the withstand voltage and thermal conductivity were evaluated. Further, the thermally conductive substrate was cut into a 5 cm square size, and the curl was measured. These results are shown in Table 8. Moreover, about the rolled copper foil thermocompression-bonded to the polyimide resin layer of the heat conductive board | substrate which has a metal layer on this single side | surface, when 1 mm180 degree peel strength (crimp surface adhesive strength) between metal / resins was measured, it was 0.5. [KN / m] or more.

[Example 2-7]
63.89 g of the polyimide solution 2a obtained in Synthesis Example 2-1 was weighed, and 53.69 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added. Mix with a centrifugal stirrer until uniform. Subsequently, 35.06 g of solvent NMP was weighed in another container, 1.096 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the above-mentioned polyimide solution containing alumina and mixed again with a centrifugal stirrer until uniform, to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied on a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating at 80 ° C. for 15 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 10 minutes to form an insulating layer in which a thermally conductive filler is dispersed in polyimide resin on the rolled copper foil, and heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina which is a heat conductive filler in this insulating layer is 70 wt%. Subsequently, evaluation was performed in the same manner as in Example 2-6. The results are shown in Table 8. Moreover, about the rolled copper foil thermocompression-bonded to the polyimide resin layer of the heat conductive board | substrate which has a metal layer on this single side | surface, when 1 mm180 degree peel strength (crimp surface adhesive strength) between metal / resins was measured, it was 0.6. It was [kN / m] or more.

[Example 2-8]
In Example 2-7, in place of heating at 120 ° C. for 5 minutes and 160 ° C. over 10 minutes, except for heating at 120 ° C. for 5 minutes and 160 ° C. over 60 minutes, Example 2-7 Similarly, a thermally conductive substrate having a metal layer on one side was produced. Subsequently, evaluation was performed in the same manner as in Example 2-6. The results are shown in Table 8. Moreover, about the rolled copper foil thermocompression-bonded to the polyimide resin layer of the heat conductive board | substrate which has a metal layer on this single side | surface, when 1 mm180 degree peel strength (crimp surface adhesive strength) between metal / resins was measured, it was 0.6. It was [kN / m] or more.

[Example 2-9]
63.89 g of the polyimide solution 2a obtained in Synthesis Example 2-1 was weighed, and 2.56 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added. Mix with a centrifugal stirrer until uniform. Subsequently, 35.06 g of solvent NMP was weighed in another container, 1.096 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the above-mentioned polyimide solution containing alumina and mixed again with a centrifugal stirrer until uniform, to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied on a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating at 80 ° C. for 15 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 10 minutes to form an insulating layer in which a thermally conductive filler is dispersed in polyimide resin on the rolled copper foil, and heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina as a heat conductive filler in this insulating layer is 10 wt%. Moreover, about the rolled copper foil thermocompression-bonded to the polyimide resin layer of the heat conductive board | substrate which has a metal layer on this single side | surface, when 1 mm180 degree peel strength (crimp surface adhesive strength) between metal / resin was measured, [KN / m] or more.

[Example 2-10]
In Example 2-9, instead of heating at 120 ° C. for 5 minutes and 160 ° C. over 10 minutes, Example 2-9 was repeated except that heating was performed at 120 ° C. for 5 minutes and 160 ° C. over 60 minutes. Similarly, a thermally conductive substrate having a metal layer on one side was produced. Subsequently, evaluation was performed in the same manner as in Example 2-6. The results are shown in Table 8. Moreover, about the rolled copper foil thermocompression-bonded to the polyimide resin layer of the heat conductive board | substrate which has a metal layer on this single side | surface, when 1 mm180 degree peel strength (crimp surface adhesive strength) between metal / resin was measured, [KN / m] or more.

[Example 2-11]
63.89 g of the polyimide solution 2a obtained in Synthesis Example 2-1 was weighed, and 23.01 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added. Mix with a centrifugal stirrer until uniform. Subsequently, 35.06 g of solvent NMP was weighed in another container, 1.096 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the above-mentioned polyimide solution containing alumina and mixed again with a centrifugal stirrer until uniform, to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied on a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating at 80 ° C. for 15 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 10 minutes to form an insulating layer in which a thermally conductive filler is dispersed in polyimide resin on the rolled copper foil, and heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina which is a heat conductive filler in this insulating layer is 50 wt%. Subsequently, evaluation was performed in the same manner as in Example 2-6. The results are shown in Table 8. Moreover, about the rolled copper foil thermocompression-bonded to the polyimide resin layer of the heat conductive board | substrate which has a metal layer on this single side, when the 1 mm 180 degree peel strength (crimp surface adhesive strength) between metal / resin was measured, 0.7 [KN / m] or more.

[Example 2-12]
In Example 2-11, instead of heating at 120 ° C. for 5 minutes and at 160 ° C. for 10 minutes, except for heating at 120 ° C. for 5 minutes and 160 ° C. for 60 minutes, Example 2-11 Similarly, a thermally conductive substrate having a metal layer on one side was produced. Subsequently, evaluation was performed in the same manner as in Example 2-6. The results are shown in Table 8. Moreover, about the rolled copper foil thermocompression-bonded to the polyimide resin layer of the heat conductive board | substrate which has a metal layer on this single side | surface, when 1 mm180 degree peel strength (crimp surface adhesive strength) between metal / resin was measured, [KN / m] or more.

[Example 2-13]
A rolled copper foil having a thickness of 18 μm was placed on the polyimide insulating layer of the heat conductive substrate having a metal layer on one side produced in Example 2-7, and pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours. A thermally conductive substrate having metal layers on both sides was obtained. The obtained heat conductive substrate was processed into a predetermined pattern, and adhesive strength, solder heat resistance and curl were measured. The results are shown in Table 9.

From Table 8, the single-sided metal thermal conductive substrates of Examples 2-6 to 2-12 containing a thermal conductive filler in the polyimide resin forming the insulating layer have high thermal conductivity and small curling. It was excellent in usability. Further, from Table 9, the double-sided metal thermally conductive substrate of Example 2-13 had good press workability, and practically sufficient adhesiveness was obtained by pressing at low temperature. In addition, the single-sided or double-sided metal thermally conductive substrates of Examples 2-6 to 2-13 had practically sufficient characteristics with respect to voltage resistance and heat resistance.

As mentioned above, although embodiment of this invention was described in detail for the purpose of illustration, this invention is not restrict | limited to the said embodiment. For example, in the above embodiment, the polyimide resin of the present invention has been exemplified by adhesives for circuit board coverlay films and bonding sheets such as FPC, but other uses such as tape automated bonding. (TAB), chip size package (CSP) and the like can be used for forming an adhesive resin.

Claims

The following components (A) and (B),
(A) a polyimidesiloxane having a ketone group, and
(B) an amino compound having at least two primary amino groups as functional groups,
A cross-linked polyimide resin obtained by reacting
The amino group of the amino compound of the component (B) reacts with at least a part of the ketone group in the polyimide siloxane of the component (A) to form a C═N bond, so that the polyimide siloxane is formed by the amino compound. A crosslinked polyimide resin, characterized by having a crosslinked structure.
The polyimidesiloxane is a structural unit represented by the following general formulas (1) and (2):

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic acid anhydride, R 1 is a divalent diaminosiloxane residue derived from diaminosiloxane, and R 2 is derived from a diamine compound. Each represents a divalent diamine residue, and Ar and / or R 2 contains a ketone group and a hydrogen bond-forming group, m and n represent the molar ratio of each constituent unit, and m is 0.35 to 1 In the range of 0, n is in the range of 0 to 0.65]
The cross-linked polyimide resin according to claim 1, which is a polyimide siloxane having the following.
3. The cross-linked polyimide resin according to claim 2, wherein the molar ratio m of the structural unit is in the range of 0.75 to 1.0, and n is in the range of 0 to 0.25.
The polyimidesiloxane is a structural unit represented by the following general formulas (1) and (2):

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic acid anhydride, R 1 is a divalent diaminosiloxane residue derived from diaminosiloxane, and R 2 is derived from a diamine compound. Each represents a divalent diamine residue, Ar contains a ketone group, R 2 contains a hydrogen bond-forming group, m and n represent the molar ratio of each constituent unit, and m is 0.35 or more and 1 Within the range of less than 0, n is in the range of more than 0 and not more than 0.65]
The cross-linked polyimide resin according to claim 1, which is a polyimide siloxane having the following.
The cross-linked polyimide resin according to claim 4, wherein the molar ratio m of the structural unit is in a range of 0.75 or more and less than 1.0, and n is in a range of more than 0 and 0.25 or less.
The crosslinked polyimide resin according to claim 2 or 4, wherein the hydrogen bond-forming group in the polyimidesiloxane is -NHCO-.
The cross-linked polyimide resin according to claim 1, wherein the polyimide siloxane is synthesized using a dihydrazide compound as a raw material.
The crosslinked polyimide resin according to claim 1, wherein the amino compound is a dihydrazide compound.
Furthermore, the plate-like inorganic filler having an average particle diameter of 2 to 25 μm is contained within a range of 5 to 200 parts by weight with respect to a total of 100 parts by weight of the component (A) and the component (B). Item 2. A crosslinked polyimide resin according to Item 1.
The following (A) component and (B) component,
(A) a polyimidesiloxane having a weight average molecular weight of 20,000 to 150,000 having a ketone group and a hydrogen bond-forming group, and (B) an amino compound having at least two primary amino groups as functional groups,
Including
Adhesive resin containing the component (B) so that the total amount of the primary amino groups is within the range of 0.004 mol to 1.5 mol with respect to 1 mol of the ketone group in the component (A). Composition.
The structural unit in which the component (A) is represented by the following general formulas (1) and (2):

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic acid anhydride, R 1 is a divalent diaminosiloxane residue derived from diaminosiloxane, and R 2 is derived from a diamine compound. Each represents a divalent diamine residue, and Ar and / or R 2 contains a ketone group and a hydrogen bond-forming group, m and n represent the molar ratio of each constituent unit, and m is 0.35 to 1 In the range of 0, n is in the range of 0 to 0.65]
The adhesive resin composition according to claim 10, wherein the adhesive resin composition is polyimide siloxane.
The adhesive resin composition according to claim 11, wherein the molar ratio m of the structural units is in the range of 0.75 to 1.0, and n is in the range of 0 to 0.25.
The structural unit in which the component (A) is represented by the following general formulas (1) and (2):

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic acid anhydride, R 1 is a divalent diaminosiloxane residue derived from diaminosiloxane, and R 2 is derived from a diamine compound. Each represents a divalent diamine residue, Ar contains a ketone group, R 2 contains a hydrogen bond-forming group, m and n represent the molar ratio of each constituent unit, and m is 0.35 or more and 1 Within the range of less than 0, n is in the range of more than 0 and not more than 0.65]
The adhesive resin composition according to claim 10, wherein the adhesive resin composition is polyimide siloxane.
14. The adhesive according to claim 13, wherein the molar ratio m of the structural unit is in a range of 0.75 or more and less than 1.0, and n is in a range of more than 0 and 0.25 or less. Resin composition.
The adhesive resin composition according to claim 10, wherein the hydrogen bond forming group in the component (A) is -NHCO-.
The adhesive resin composition according to claim 10, wherein the component (A) is synthesized using a dihydrazide compound as a raw material.
The adhesive resin composition according to claim 10, wherein the component (B) is a dihydrazide compound.
11. The composition further comprises (C) 5 to 200 parts by weight of a plate-like inorganic filler having an average particle diameter in the range of 2 to 25 μm with respect to 100 parts by weight of the total of the components (A) and (B). The adhesive resin composition as described in 2.
A cured product obtained by curing the adhesive resin composition according to claim 10.
A cover lay film in which an adhesive layer and a cover lay film material layer are laminated,
The coverlay film in which the said adhesive bond layer is formed using the adhesive agent resin composition of Claim 10.
A circuit board comprising: a base material; a wiring layer formed on the base material; and the coverlay film according to claim 20 covering the wiring layer.
A polyimide siloxane having a ketone group and a hydrogen bond forming group by mixing an acid anhydride component having a ketone group, a diamine compound having a hydrogen bond forming group and a diamine component containing a diaminosiloxane, and imidation by heating. Forming a process,
Forming hydrogen bonds between adjacent main chains in the polyimidesiloxane; and
At least a part of the ketone group of the polyimide siloxane is reacted with an amino group of an amino compound having at least two primary amino groups as a functional group to form a C = N bond, and the polyimide siloxane is crosslinked with the amino compound. The process of
A method for producing a crosslinked polyimide resin comprising:
In a thermally conductive substrate having a metal layer on one or both sides of an insulating layer having at least one filler-containing polyimide resin layer in which a thermally conductive filler is dispersed in a polyimide resin, the thermally conductive filler of the filler-containing polyimide resin layer The content of is in the range of 5 to 80 wt%, and the polyimide resin in the filler-containing polyimide resin layer is a structural unit represented by the following general formulas (1) and (2):

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic anhydride, R 1 is a divalent diaminosiloxane residue derived from diaminosiloxane, R 2 is an aromatic diamine and / or Each represents a divalent diamine residue derived from an aliphatic diamine, Ar and / or R 2 contains a ketone group, m and n represent the molar ratio of each constituent unit, and m is 0.4 In the range of -1.0 and n is in the range of 0-0.6]
The polyimide group having the amino group reacts with the amino group of the amino compound having at least two primary amino groups as functional groups to form a C═N bond, so that the polyimide siloxane has the amino group. A thermally conductive substrate, which is a crosslinked polyimide resin having a structure crosslinked by a compound.
The thermally conductive substrate according to claim 23, wherein the amino compound is a dihydrazide compound.
The thermally conductive substrate according to claim 23, wherein the thermally conductive filler is at least one filler selected from silica, alumina, aluminum nitride, boron nitride, silicon nitride, and magnesia.
The thermally conductive substrate according to claim 23, wherein the thermally conductive filler is a spherical alumina having an average particle diameter in the range of 0.5 to 10 µm.
The thermally conductive substrate according to claim 23, wherein the polyimide siloxane has a hydrogen bond forming group.
A step of applying a solution of a filler-containing polyimide resin in which the polyimide siloxane, the thermally conductive filler, and the amino compound are mixed onto a metal base material to be the metal layer and drying to form a coating film;
Heating the coating film, and reacting an amino group of the amino compound with at least a part of the ketone group in the polyimidesiloxane to form a C = N bond to form a filler-containing polyimide resin layer;
The thermally conductive substrate according to claim 23, which is produced by a method comprising:
The thermally conductive substrate according to claim 28, wherein the filler-containing polyimide resin layer is in a semi-cured state.
A thermally conductive polyimide film comprising a filler-containing polyimide resin layer in which a thermally conductive filler is dispersed in a polyimide resin,
The content of the heat conductive filler in the filler-containing polyimide resin layer is in the range of 5 to 80 wt%, and the polyimide resin in the filler-containing polyimide resin layer is represented by the following general formulas (1) and (2). Unit:

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic anhydride, R 1 is a divalent diaminosiloxane residue derived from diaminosiloxane, R 2 is an aromatic diamine and / or Each represents a divalent diamine residue derived from an aliphatic diamine, Ar and / or R 2 contains a ketone group, m and n represent the molar ratio of each constituent unit, and m is 0.4 In the range of -1.0 and n is in the range of 0-0.6]
The polyimide group having the amino group reacts with the amino group of the amino compound having at least two primary amino groups as functional groups to form a C═N bond, so that the polyimide siloxane has the amino group. A thermally conductive polyimide film, which is a crosslinked polyimide resin having a structure crosslinked by a compound.