JP2016124982A - Crosslinked polyimide resin, method for production thereof, adhesive resin composition, cured material thereof, coverlay film, and circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crosslinked polyimide resin capable of forming an adhesive layer which has a stable coating performance even when producing in an industrial scale, is excellent in solder heat resistance and is capable of holding an excellent adhesive performance for a long period under high-temperature environment.SOLUTION: A crosslinked polyimide resin is obtained by reacting polyimide having ketone groups with an amino compound having at least two primary amino groups as a functional group, and has a crosslinked structure in which the amino group of the amino compound reacts with at least a portion of the ketone group in polyimide to form a C=N bond. The resin has a sea-island phase separation structure. For details, when the phase difference in phase imaging in observation by an atomic force microscope is 20° or more in such a state as processed to a sheet shape, a small phase is made to be 0 and a large phase to be 100. When defining the area in the range of 0 to 30 in the phase difference converted to 100 as a land, and the area other than the land as a sea, at least one land area having the area within the range of 20 μmor more and 140 μmor less is present in an observation area of 3,600 μm.SELECTED DRAWING: Figure 5

Description

  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 method for producing the same, and use thereof.

  In recent years, with the progress of downsizing, 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 the FPC, a coverlay film is used for the purpose of protecting the wiring portion. 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, in which one or more plasticizers selected from phosphoric acid ester-based, phthalic acid ester-based, polyester-based and fatty acid ester-based materials are blended has been proposed (for example, Patent Document 1). ).

  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 hygroscopicity, adhesive force during heating, and PCT resistance of polyimide resin used for an adhesive film. 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, Patent Document 2). 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 to cause a molecular weight to be controlled after the reaction is continued until no increase occurs (for example, Patent Document 3).

  In addition, since the soldering process is almost essential in the processing of the FPC, 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.

  For these reasons, the present inventors have previously obtained a crosslinked structure having a C═N crosslinked structure in which an amino compound having at least two primary amino groups as functional groups is reacted with the ketone group previously contained in the polyimide. A polyimide resin was proposed (for example, Patent Documents 4 to 6). Since these crosslinked polyimide resins are excellent in solder heat resistance and can maintain excellent adhesive performance for a long period of time even in a high temperature environment, they are highly useful as adhesives for coverlay films and the like. However, when these cross-linked polyimide resins are used to produce an adhesive on an industrial scale, the coating performance may vary, leaving room for further improvement.

JP-A-10-212468 JP 2006-117945 A JP 2004-359874 A International Publication WO2011 / 077917 JP 2013-1730 A JP 2013-1750 A

  Therefore, the object of the present invention is to form an adhesive layer that has stable coating performance even when produced on an industrial scale, has excellent solder heat resistance, and can maintain excellent bonding performance over a long period of time even in a high temperature environment. It is to provide a possible cross-linked polyimide resin.

  As a result of diligent research to solve the above problems, the present inventors have found that a crosslinked polyimide resin having a sea-island phase separation structure is stabilized in coating performance even when produced on an industrial scale, The present invention has been completed.

That is, the crosslinked polyimide resin of the present invention is obtained by reacting (A) a polyimide having a ketone group and (B) an amino compound having at least two primary amino groups as functional groups. It is a crosslinked polyimide resin having a crosslinked structure in which an amino group of an amino compound reacts with at least a part of the group to form a C═N bond. When the cross-linked polyimide resin of the present invention is processed into a sheet shape and the phase difference in phase imaging by atomic force microscope observation is 20 ° or more, the smaller phase is 0, and the larger phase is 100. "island" regions within 0-30 range when converted into 100, in the case where the other region as "sea", the area 3600Myuemu ² within the observation area, the area is 20 [mu] m ² or more 140 .mu.m ² or less It is characterized by having a sea-island phase separation structure in which one or more island regions exist in the range.

  In the crosslinked polyimide resin of the present invention, the sea-island phase separation structure may be formed by a crosslinking reaction.

  In the crosslinked polyimide resin of the present invention, the polyimide may be a polyimide having structural units represented by the following general formulas (1) and (2).

[In the formula, Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic acid anhydride, R ₁ is a divalent diamine residue derived from a diaminosiloxane or an aliphatic diamine compound, and R ₂ is a diamine compound. Each represents a divalent diamine residue derived from Ar, and / or 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 Within the range of 35 to 1.0, n is within the range of 0 to 0.65]

  In the crosslinked polyimide resin of the present invention, the molar ratio m of the structural units may be in the range of 0.75 to 1.0, and n may be in the range of 0 to 0.25.

  The crosslinked polyimide resin of the present invention may be one in which the polyimide 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.

  The crosslinked polyimide resin of the present invention further contains a plate-like inorganic filler having an average particle diameter of 2 to 25 μm within a range of 5 to 200 parts by weight with respect to 100 parts by weight of the resin component. May be.

The adhesive resin composition of the present invention is an adhesive resin composition containing a polyimide having a ketone group and an amino compound having at least two primary amino groups as functional groups. The adhesive resin composition of the present invention is obtained by reacting the polyimide with the amino compound, and the amino group of the amino compound reacts with at least a part of the ketone group in the polyimide to form a C = N bond. When the cross-linked polyimide resin having a cross-linked structure is processed into a sheet shape and the phase difference in phase imaging by atomic force microscope observation is 20 ° or more, the smaller phase is 0, and the larger phase is 100 island regions within 0-30 range when converted into 100 phase difference, when the other area with the sea, the range area in the observation area 3600Myuemu ^2, the area of 20 [mu] m ² or more 140 .mu.m ² or less It has a sea-island phase separation structure in which one or more island regions exist.

  The hardened | cured material of this invention contains the crosslinked polyimide resin in any one of the said.

  The coverlay film of this invention is equipped with the adhesive bond layer containing the crosslinked polyimide resin in any one of the said.

  The circuit board of the present invention includes the coverlay film.

The method for producing a crosslinked polyimide resin of the present invention comprises a step of mixing an acid anhydride component having a ketone group and a diamine component and imidizing by heating to form a polyimide having a ketone group; And a polyimide compound having at least two primary amino groups as functional groups, and at least a portion of the ketone group of the polyimide has at least two primary amino groups as functional groups. A method for producing a crosslinked polyimide resin comprising a step of reacting an amino group of an amino compound to form a C═N bond to form a crosslinked structure. The method for producing a crosslinked polyimide resin of the present invention is such that the phase is small when the crosslinked polyimide resin is processed into a sheet and the phase difference in phase imaging by atomic force microscope (AFM) observation is 20 ° or more. Observation with an area of 3600 μm ² when the area in the range of 0 to 30 when the phase is converted to 100 with the side being 0 and the larger being 100 is “island” and the other area is “sea” in the region, characterized in that island region area is within the range of 20 [mu] m ² or more 140 .mu.m ² or less has a sea-island phase separation structure present one or more.

  Since the crosslinked polyimide resin of the present invention has a specific sea-island phase separation structure, it has stable coating performance even when produced on an industrial scale. The crosslinked polyimide resin of the present invention has a structure in which at least a part of the ketone group in the polyimide reacts with the amino group of the amino compound to form a C═N bond, and at least a part of the polyimide is crosslinked with the 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.

It is drawing which shows the evaluation result of the flow property in Example 1, 2, and the comparative example 1, solder heat resistance, and adhesive strength. 4 is a graph showing the results of rheometer evaluation of a sample in Example 1. 6 is a graph showing the results of rheometer evaluation of a sample in Example 2. 6 is a graph showing the results of rheometer evaluation of a sample in Comparative Example 1. 2 is a drawing showing the results of AFM observation in Examples 1 and 2 and Comparative Example 1. FIG.

[Crosslinked polyimide resin]
The crosslinked polyimide resin of the present embodiment includes the following components (A) and (B),
(A) a polyimide having a ketone group and a hydrogen bond-forming group,
as well as,
(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 of the component (B) reacts with at least a part of the ketone group in the polyimide of the component (A) to form a C = N bond. The polyimide has a structure crosslinked with the amino compound.

  In the crosslinked polyimide resin of the present invention, the crosslinking formation rate (degree of curing) does not have to be a state where the curing of the polyimide resin by the crosslinking formation is completed, as long as practically sufficient moisture-resistant soldering heat resistance can be secured. Good. 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.

Further, the crosslinked polyimide resin of the present embodiment has a smaller phase when the phase difference in the phase imaging by atomic force microscope (AFM) observation is 20 ° or more in the state of being processed into a sheet shape. The area within the range of 0-30 when the phase difference is converted to 100 with 0 being the larger and 100 being the larger one is “island”, and the other area is “the sea”, and the observation area is 3600 μm ² within the island region area is within the range of 20 [mu] m ² or more 140 .mu.m ² or less are present more than one. When there is no island region having an area within the above range, the adhesive is liable to flow out at the time of thermocompression bonding and the solder heat resistance is likely to deteriorate. In addition, it is preferable that the island regions exist in a ratio of about 5% in total (about 180 μm ^{2 in} total) in the observation region including those having an area of less than 20 μm ² . When the area ratio of the island region in the observation region greatly exceeds 5%, or there is an island region where one area exceeds 140 μm ² , the crosslinking reactivity becomes too high, so the curing proceeds quickly, There is a possibility of causing a decrease in adhesive strength due to poor adhesion during thermocompression bonding. The reason why the phase difference in phase imaging is defined as 20 ° or more is to clarify that sea-island phase separation has occurred.

[Polyimide]
In a preferred embodiment of the crosslinked polyimide resin of the present invention, the component (A) may be a polyimide having structural units represented by, for example, general formulas (1) and (2).

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 derived from a diaminosiloxane or an aliphatic diamine compound. It is a divalent diamine residue, 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 representing 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, most preferably in the range of 0.01 to 0.25. Is within.

Formula (1), a structural unit represented by (2), in the group Ar and / or groups R _2, preferably comprising a ketone group in the radical Ar, the ketone group is involved in the reaction of the amino compound To do. 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'-benzophenonetetracarboxylic 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 polyimide 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 chains, and the ketone group that is the reaction point of the crosslinking reaction with the amino compound can be brought close to each other. 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). In order to efficiently form hydrogen bonds between adjacent polyimide main chains, the molar ratio of hydrogen bond-forming groups to all diamines is in the range of more than 0 and not more than 1.3, more preferably more than 0 and less than 0.00. It can be in the range of 5 or less, most preferably in the range of 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 represent a divalent organic group that may contain an oxygen atom, R _{5 to} R ₈ each represent a hydrocarbon group having 1 to 6 carbon atoms, M ₁ that is the average number of repetitions 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, and R _{5 to} R ₈ are each 1 to 1 carbon atoms in order to impart solubility of the polyimide. 6 having a mean repeating number of m ₁ of 5 to 15 is preferable.

  The above-mentioned 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 this 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 polar groups are contained in the plasticizer, an adhesive resin using polyimide having the structural units represented by the general formulas (1) and (2) is an advantage of not containing the plasticizer. It is mentioned that the amount of polar groups contained in the composition can be suppressed. For this reason, in this invention, 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 by increasing the siloxane bond, there is an effect of reducing curing shrinkage due to a decrease in the imide bond site of polyimide.

Thus, by introducing the siloxane skeleton into the polyimide using the diaminosiloxane represented by the above general formula (4), the resulting polyimide is given fluidity at the time of thermocompression bonding and filled on the printed circuit wiring. Can be improved. As a specific example 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 equation (4) to Formula (9), _{m 1} is an average repeating number is in the range of 1 to 20, preferably in the range of 5-15. When m ₁ is smaller than _1, the filling property when the 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- Bis [4- (3-aminophenoxy) benzoyl] benzene (BABB) and the like can be mentioned.

Moreover, in the structural unit represented by the general formula (1), as a raw material for forming a divalent diamine residue derived from the aliphatic diamine compound of the group R _1, a fat having a cyclic structure in the molecule Preferred are aliphatic diamines, aliphatic diamines in the range of 24 to 48 carbon atoms, or dimer acid diamines, and more preferred are dimer acid diamines. Here, the cyclic structure means an aliphatic cyclic structure other than the aromatic ring, and may have an unsaturated bond in the ring. In addition, if the aliphatic diamine has less than 24 carbon atoms, the solubility may be lowered and handling may be difficult, and if the carbon number exceeds 48, crosslinking due to imine bonds between polyimide resins may not be formed. By selecting an aliphatic diamine as described above, flexibility can be imparted to the polyimide resin, and an imine bond can be effectively formed, so that a decrease in adhesive force is not caused even in use in a high temperature environment. be able to.

The dimer acid type diamine preferably used as a raw material for forming a divalent diamine residue derived from an aliphatic diamine of the group R ₁ has two terminal carboxylic acid groups (—COOH) of dimer acid as 1 It means a diamine substituted with a primary aminomethyl group (—CH ₂ —NH ₂ ) or an amino group (—NH ₂ ). Dimer acid is a known dibasic acid obtained by an intermolecular polymerization reaction of an unsaturated fatty acid, and its industrial production process is almost standardized in the industry, and an unsaturated fatty acid having 11 to 22 carbon atoms is converted into a clay catalyst. It is obtained by dimerization with the above. The dimer acid obtained industrially is mainly composed of a dibasic acid having 36 carbon atoms obtained by dimerizing an unsaturated fatty acid having 18 carbon atoms such as oleic acid or linoleic acid, depending on the degree of purification. , Containing any amount of monomeric acid (18 carbon atoms), trimer acid (54 carbon atoms), and other polymerized fatty acids having 20 to 54 carbon atoms. In the present invention, it is preferable to use dimer acid having a dimer acid content increased to 90% by weight or more by molecular distillation. In addition, although a double bond remains after the dimerization reaction, in the present invention, a dimer acid that is further reduced in the degree of unsaturation by hydrogenation reaction is included.

  As a feature of the dimer acid diamine, a characteristic derived from the skeleton of the dimer acid can be provided. That is, since the dimer acid type diamine is a macromolecular aliphatic having a molecular weight of about 560 to 620, the molecular molar volume can be increased and the polar groups of the polyimide can be relatively reduced. Such a feature of the dimer acid type diamine is considered to contribute to suppression of a decrease in heat resistance of the polyimide.

  The dimer acid type diamine is commercially available. For example, PRIAMINE 1073 (trade name) manufactured by Croda Japan, PRIAMINE 1074 (trade name), Versamine 551 (trade name), Versamine 552 (product) manufactured by Cognis Japan. Name).

In the structural unit represented by the general formula (2), as a 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 May 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.

Further, in the structural unit represented by the general formula (2), as other diamine compound which 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.

  The above acid anhydrides and diamines that are the raw materials for polyimide may be used alone or in combination of two or more. In addition, acid anhydrides and diamines other than those described above can be used in combination.

[Synthesis of polyimide]
The polyimide of component (A) can be produced by reacting the aromatic tetracarboxylic acid anhydride and the diamine component in a solvent to form a polyamic acid as a precursor resin, followed by heat ring closure. For example, it is a polyimide precursor by dissolving an acid anhydride component and a diamine component in an approximately equimolar amount in an organic solvent and stirring and polymerizing at a temperature in the range of 0 to 100 ° C. for 30 minutes to 24 hours. 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 for 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, a heat treatment in which heating is performed in the solvent under a temperature condition in the range of 80 to 300 ° C. for 1 to 36 hours is suitably employed.

  In the synthesis of polyimide, it is preferable to perform heat treatment of the polyamic acid by rapid heating at a temperature rising rate within a range of 100 ° C./hour, preferably 100 ° C./hour to 150 ° C./hour, for example. Such rapid heating makes it possible to form the specific sea-island phase separation structure in the crosslinked polyimide resin, and to improve the coating performance of the crosslinked polyimide resin. In this case, imidation can be completed by heating to a temperature of, for example, 150 ° C. or higher at the rate of temperature rise and then maintaining the same temperature for about 1 to 10 hours.

  In addition, as another method for forming the specific sea-island phase separation structure in the crosslinked polyimide resin, the acid anhydride component and the diamine component are reacted in a solvent and heated while heating the acid anhydride component little by little. It is also possible to employ a reaction method in which the formation of polyamic acid and imidization proceed simultaneously by additionally supplying. This method is effective when it takes time to uniformly heat the entire reaction system, such as mass synthesis on an industrial scale. When heating takes time, if all the monomers are added from the beginning, there is a possibility that they react non-uniformly due to the difference in reactivity. In order to reduce the influence of the reactivity of the monomer, there is a method in which the monomer is added after heating, but in a large-scale synthesis on an industrial scale, there is a possibility that the reaction proceeds too quickly and gelation occurs. Therefore, it is desirable to react uniformly by gradually adding the acid anhydride component while raising the temperature. Here, the total amount of the acid anhydride component to be additionally supplied is within a range of 1/5 to 3/5 in terms of molar ratio with respect to the sum of the initial charge amount of the acid anhydride component and the additional supply amount. Is preferred. In this case, the additional supply of the acid anhydride component is preferably performed continuously or intermittently, for example, over 1 to 10 hours while heating, and then, for example, a temperature of 150 ° C. or higher is maintained for about 10 to 30 hours. By doing so, imidization can be completed. When the additional supply of the acid anhydride component is intermittently performed, for example, 1/20 to 1/3 of the total additional supply may be added by one additional supply. The additional supply of such an acid anhydride component also makes it possible to form the specific sea-island phase separation structure, and to improve the coating performance of the crosslinked polyimide resin.

  (A) When preparing the component polyimide, the mixing 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 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 has an imide structure obtained by the reaction of an aromatic tetracarboxylic acid anhydride and a diamine component. For example, when used as an adhesive for a coverlay film, the diffusion of copper A completely imidized structure is most preferred for suppression. However, a part of the polyimide may be amic acid. The imidation 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). Based on the absorbance of C═O stretching derived from an imide group of 1780 cm ⁻¹ , based on the benzene ring absorber.

  Since the polyimide obtained as described above has a hydrogen bond forming group in the molecular structure, hydrogen bonds are generated between adjacent polyimide main chains even at room temperature. For example, when the hydrogen bond forming group contained in the polyimide is an —NHCO— group, a hydrogen bond is generated between the NH group of one adjacent polyimide chain and the CO group of the other polyimide chain. As a result, a large number of polyimide chains can be brought close to a certain degree of orientation, and the adjacent polyimide chains can be brought close to each other as a reaction point for a crosslinking reaction with an amino compound. Such hydrogen bond formation proceeds by holding the polyimide in a solvent solution, 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 an 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 of the component (A), Illustrative examples include I) aromatic diamines, (II) diaminosiloxanes, (III) aliphatic amines, and (IV) dihydrazide compounds.

(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 the aromatic diamine 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, bis 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′-diamino Diphenylethane, 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-phenylenediamine , P-phenylenediamine, 2,6-diaminopyridy 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-di Examples include amines, 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 diaminosiloxane, diaminosiloxane represented by the following general formula (14) or an oligomer thereof is preferably exemplified.

(Here, R ₁₁ and R ₁₂ each represent a divalent hydrocarbon group that may contain an oxygen atom, and R _{13 to} R ₁₆ each represent a hydrocarbon group having 1 to 6 carbon atoms. M ₁ represents a number of ₁ to 20, preferably 1 to 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, 3,3′-diaminodipropylamine, amines containing nitrogen atoms such as 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 include amines having a sulfur atom such as 2'-thiobis (ethylamine). These 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, 2,6-pyridinediacid dihydrazide, itaconic acid dihydrazide and the like can be mentioned. The above dihydrazide compounds may be used alone or in combination of two or more.

  Of 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 reaction equilibrium is biased toward the product side, and the reverse reaction in the direction of generating the ketone group of the raw material polyimide and the amino group of the dihydrazide compound is less likely to occur. it is conceivable that.

  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 of (I), (II) or (III) and the dihydrazide compound of (IV) at a predetermined blending ratio, taking advantage of the properties of the amino compound of (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. Among these, amino compounds having a molecular weight of 100 to 1,000 are particularly preferable. 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, and the remaining amino group is sterically bulky so that the remaining Amino groups tend to be difficult to bond C═N.

[Method for producing crosslinked polyimide resin]
The method for producing a cross-linked polyimide resin of the present invention comprises mixing an acid anhydride component having a ketone group and a diamine component and imidizing by heating to obtain a polyimide having a ketone group as the component (A). Forming, and
At least a part of the ketone group of the polyimide is reacted with the amino group of the amino compound having at least two primary amino groups as functional groups, which is the component (B), to form a C = N bond, and the polyimide is converted into an amino group. And a step of crosslinking with a compound.

  Specifically, the resin solution containing the polyimide of the component (A) and preferably having a hydrogen bond between the main chains has at least two primary amino groups of the component (B) as functional groups. It is produced by adding an amino compound and subjecting some or all of the ketone groups of the polyimide to a condensation reaction with the primary amino group of the amino compound. By this condensation reaction, crosslink formation proceeds between polyimide chains, and the adhesive resin composition is gradually cured according to the degree of crosslink formation. In this case, the primary amino group in total 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 such that the primary amino group is less than 0.004 mol in total with respect to 1 mol of the ketone group, the polyimide resin is not sufficiently crosslinked by the amino compound, so the adhesive resin composition is cured. In the cured product after soldering, the solder heat resistance tends to be difficult to develop, and when the added amount of the amino compound exceeds 1.5 mol, the unreacted amino compound acts as a thermoplastic agent. Or the long-term heat resistance at high temperatures.

  Further, the curing by the condensation reaction is not particularly limited as long as the ketone group in the polyimide 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 the ketone group in the polyimide 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 a range of 60 to 200 ° C, for example. When an aromatic amine is used, heat condensation is performed within a range of 120 to 220 ° C, for example. It is preferable to carry out. The temperature of the heat condensation is, for example, 120 to 120 for reasons such as 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 polyimide. The inside of the range of 220 degreeC is preferable, and the inside of the range of 140-200 degreeC is more preferable. 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. From the viewpoint of obtaining practically sufficient moisture-absorbing solder 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, for example, an absorption derived from a ketone group in a polyimide near 1670 cm ⁻¹ by measuring an infrared absorption spectrum using a Fourier transform infrared spectrophotometer (commercial product: FT / IR620 manufactured by JASCO Corporation). It can be confirmed by the decrease or disappearance of the peak and the appearance of an absorption peak derived from an imine group near 1635 cm ⁻¹ , or the Raman spectrum using a Raman spectrophotometer (commercial product: NRS-3100 manufactured by JASCO). Can be confirmed by the appearance of a peak derived from an imine group in the vicinity of 1567 cm ⁻¹ . Further, whether or not a practically sufficient moisture-resistant soldering heat resistance can be expressed 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 ⁴ Pa · s or more. If the viscosity of the cross-linked polyimide resin at a temperature of 260 ° C. is 1 × 10 ⁴ Pa · s or more, it can be considered that 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 in this way is that it is difficult to directly measure the cross-linking formation rate due to the C = N bond. 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 cross-linked polyimide resin at a temperature of 260 ° C. is 1 × 10 ⁴ Pa · s or higher, it is considered that a 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 polyimide and the primary amino group of the amino compound is, for example,
(A) Following the synthesis (imidation) of polyimide, adding an amino compound and heating,
(B) An excess amount of an amino compound is charged in advance as a diamine component, and the polyimide is heated together with the remaining amino compound not involved in imidization (or amidation) following the synthesis (imidation) of the polyimide, or
(C) heating after processing the polyimide composition to which the amino compound is 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 in the production of the polyimide, and the molecular weight of the resulting polyimide may be extremely reduced. In a cured product, sufficient heat resistance tends to be difficult to obtain. 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 with a polyimide as described in (a) or (c) above. It is preferably added after completion of (imidization). In the case of the above (c), the heat condensation is performed by, for example, forming heat or 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 are mixed. Thereafter, it can be performed by using heat or the like at the time of thermocompression bonding to the circuit board having the wiring layer.

[Inorganic filler]
The crosslinked polyimide resin of the present invention can contain a plate-like inorganic filler having an average particle diameter in the range of 2 to 25 μm as an arbitrary component (C). (C) When the inorganic filler of component (C) is blended, when the cross-linked polyimide resin is used for an adhesive layer of a coverlay film, for example, the permeation of oxygen in the atmosphere is blocked by the inorganic filler having gas barrier properties. The oxidation of copper wiring and the diffusion of copper 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, and kaolin.

  The inorganic filler preferably has an average particle size 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. Moreover, 0.1-100 micrometers is preferable and, as for the frequency distribution of the particle size of an inorganic filler, 0.5-70 micrometers is more preferable. 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.

  (C) The compounding quantity of the inorganic filler of a component is 5-200 weight part with respect to a total of 100 weight part of the said (A) component and (B) component, Preferably it is 10-150 weight part, Furthermore, Preferably it is 30-100 weight part, It is 40-80 weight part desirably. 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.

[Adhesive resin composition]
The adhesive resin composition of the present invention contains the polyimide [(A) component] and an amino compound [(B) component] having at least two primary amino groups as functional groups as essential components. . 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). It has the property that a ketone group and a primary amino group of an amino compound undergo a condensation reaction to form a C═N bond. In this way, the crosslinked polyimide resin having a crosslinked structure is processed into a sheet, and when the phase difference in phase imaging by atomic force microscope observation is 20 ° or more, the smaller phase is 0 and the larger phase is 100. region island phase difference within 0-30 range when converted into 100 as a, in the case where the other region and the sea, the area 3600Myuemu ² within the observation area, the area is 20 [mu] m ² or more 140 .mu.m ² or less It has a sea-island phase-separated structure in which one or more island regions are present.

  Moreover, the adhesive resin composition of this invention changes into the hardened | cured material of this invention by the condensation reaction of a polyimide 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 and the primary amino group of the amino compound does not proceed any more, but also room for the crosslinking reaction. Including the semi-cured state leaving In the adhesive resin composition of the present invention, the weight average molecular weight of the component (A) is preferably in the range of, for example, 30,000 to 200,000, and sufficient moisture-resistant solder heat resistance by heating at 160 ° C. for 2 hours. From the viewpoint of obtaining properties, a range of 70,000 to 140,000 is more preferable. 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. An amino compound is contained so that it may become mol-0.9 mol, Most preferably, it is 0.04 mol-0.5 mol.

  It is preferable that the adhesive resin composition of the present invention contains the inorganic filler of the component (C) as an optional component together with the polyimide 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.

  When blending optional components other than the inorganic filler of component (C) in the adhesive resin composition of the present invention, for example, the blended amount of 1 to 10 parts by weight in total of the optional components with respect to 100 parts by weight of the crosslinked polyimide resin It is preferable that the blending amount is 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, after applying the adhesive resin composition of the present invention in a solution state (for example, a varnish containing a solvent) on one side of a cover lay film material, for example, 60 to 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 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, for example, 60 to 220 ° C, and more preferably 80 to 200 ° C. Moreover, it peels, after apply | coating the adhesive resin composition of this invention in the state of a solution (for example, varnish shape containing a solvent) on arbitrary base materials, for example, drying at the temperature of 80-180 degreeC. 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. Also in this case, it is possible to heat-condense the ketone group of the polyimide and the primary amino group of the amino compound using heat at the time of 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 polyimide 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, for example, 80 to 180 ° C. . 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 applying 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-condensate the polyimide ketone group and the primary amino group of the amino compound. It can also be condensed.

  Moreover, a coverlay film and a bonding sheet are good also as a form which has a release material layer by bonding a release material on 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 and bonding sheet obtained by molding using the adhesive resin composition of the present invention and causing the above-mentioned heat condensation reaction by heat treatment are obtained by cross-linking polyimide resin obtained by reaction of polyimide and amino compound. Since it contains, 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 includes at least a base material, a wiring layer made of a metal such as copper formed on the base material in a predetermined pattern, and the cover lay film of the present invention covering the wiring layer. And. The base material of the circuit board is not particularly limited, but in the case of FPC, the same material as the coverlay film material is preferably used, and the base material made of polyimide resin is preferably used.

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 reaction of polyimide and amino compound, copper diffusion from the copper wiring is suppressed, and even if it is used repeatedly in a high temperature environment, it is excellent Adhesion can be maintained over a long period of time. 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.

  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 and the primary amino group of the amino compound are unreacted in the state of the coverlay film, the condensation reaction is performed using the heat when the coverlay film is thermocompression bonded to the circuit wiring. 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.

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The cross-linked polyimide resin of the present embodiment has a specific sea-island phase separation structure as described above, and thus has stable coating performance even when produced on an industrial scale. The reason has not been clarified yet, but it is presumed as follows.

  First, as a mechanism for deteriorating the flowability of the adhesive resin composition, it is considered that the cross-linking between the polyimide and the diamine compound is incomplete at the thermocompression bonding temperature. For example, when cross-linked polyimide resin is used as the adhesive layer of the coverlay film, if the cross-linking is incomplete, the fluidity is high at around 160 ° C., which is the thermocompression bonding temperature, and the resin flows out during application. In this case, as shown in Comparative Example 1 (FIG. 4) to be described later, a significant decrease in viscosity is observed in a temperature range of about 160 ° C. to 250 ° C. On the other hand, as shown in Examples 1 and 2 (FIGS. 2 and 3) to be described later, when the crosslinking is sufficiently advanced, the viscosity hardly decreases in a temperature range of about 160 ° C. to 250 ° C. Rather, since an increasing tendency is observed, good flowability without resin flow is maintained.

  In the crosslinked polyimide resin of the present embodiment, the island region is rich in aliphatic chain units such as siloxane units that are diaminosiloxane residues and dimer acid type diamine residues based on the results of phase imaging by AFM observation. It is considered to be an area included in As described above, the siloxane unit and the aliphatic chain unit are sparse in molecular structure as compared with a structure rich in aromatic rings, and are relatively high water permeability in the crosslinked polyimide resin. it is conceivable that. At the time of cross-linking between the polyimide and the diamine compound, moisture is generated by a dehydration condensation reaction. Therefore, the cross-linking can be promoted by removing the water. In the case of having a specific sea-island phase separation structure as described above, moisture generated by the cross-linking reaction can be quickly released out of the polymer through the island region. It is presumed that the flowability in the pressure bonding temperature range is improved. On the other hand, when there is no specific sea-island phase separation structure as described above, the water staying in the polymer delays the cross-linking formation, and the cross-linking formation remains in an incomplete state. It is presumed that the performance will decrease.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but 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, and the force at the time of peeling at a speed of 50 mm / min in the 180 ° direction is defined as the adhesive strength.

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

[Solder heat resistance test (dry)]
A printed circuit board on which a circuit of wiring width / wiring interval (L / S) = 1 mm / 1 mm is formed by processing a polyimide copper-clad laminate (trade name: Espanex MC18-25-00FRM, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) Prepared. The adhesive surface of the test piece was placed on the wiring of the printed circuit board and pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 120 minutes. After drying this test piece with copper foil at 105 ° C, it is immersed in a solder bath set at each evaluation temperature for 10 seconds, and its adhesion state is observed to check for defects such as foaming, blistering and peeling. did. 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.

[Solder heat resistance test (moisture absorption)]
A printed circuit board on which a circuit of wiring width / wiring interval (L / S) = 1 mm / 1 mm is formed by processing a polyimide copper-clad laminate (trade name: Espanex MC18-25-00FRM, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) Prepared. The adhesive surface of the test piece was placed on the wiring of the printed circuit board and pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 120 minutes. This test piece with copper foil was allowed to stand for 72 hours at 40 ° C. and 80% relative humidity, then immersed in a solder bath set at 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, “260 ° C.” means that no defect is observed when evaluated in a solder bath at 260 ° C.

[Adhesive strength]
The adhesive surface of a test piece cut out to a width of 10 mm and a length of 100 mm was placed on a glossy surface (thickness of rust-proof metal removed) of a copper foil (thickness of 35 μm), temperature 160 ° C., pressure 2 MPa, time 120 minutes. After pressing under the conditions, the strength at the time of peeling at a speed of 50 mm / min in the 180 ° direction was determined as the adhesive strength using a tensile tester (Strograph-M1 manufactured by Toyo Seiki Co., Ltd.).

[Flow performance evaluation]
An adhesive was applied on the polyimide film so that the thickness after drying was 30 μm, and a hole with a diameter of 6 mm was formed. Place the adhesive surface on one side CCL copper foil, press under conditions of temperature 160 ° C, pressure 2MPa, time 120min. If the protruding width of the adhesive is 1mm or less, "no problem", exceeding 1mm Was determined to be “flowing out”.

[Measurement of glass transition temperature (Tg)]
A 5 mm × 20 mm film was measured with a dynamic viscoelasticity measuring device (DMA: manufactured by TA Instruments, RSA3) from 30 ° C. to 150 ° C. at a heating rate of 4 ° C./min and a frequency of 11 Hz. The glass transition temperature (Tg) was determined from the value.

[CTE measurement]
The temperature of a 3 mm × 20 mm size film was increased from 30 ° C. to 250 ° C. at a rate of 10 ° C./min while applying a 5.0 g load with a thermomechanical analyzer (TMA: manufactured by Bruker, 4000SA), The linear expansion coefficient was measured from the amount of elongation of the film with respect to temperature. α1 represents a linear expansion coefficient below the glass transition temperature, and α2 represents a linear expansion coefficient above the glass transition temperature.

[Tensile test (elastic modulus, elongation, maximum point stress)]
A polyimide resin film prepared with a thickness of 30 μm was cut into a strip shape having a width of 12.5 mm and a length of 120 mm to form a test piece, and a tensile tester (manufactured by Toyo Seiki Co., Ltd., Strograph-R1) was used. Measurement was performed at a crosshead speed of 25 mm / min and a distance between chucks of 101.6 mm, and the value obtained by dividing the measured load by the cross-sectional area of the test piece was taken as the tensile strength.

[Rheometer measurement]
An adhesive was applied onto the release PET film so that the thickness after drying was 30 μm. The adhesive film is peeled from the release PET film, about 10 adhesive films are laminated, and the viscosity of the sample is measured using a rheometer (Haake, RS150 RheoStress) at a temperature increase rate of 4 ° C./min. Changes were measured.

[AFM observation]
After the adhesive was applied on the release PET film so that the thickness after drying was 30 μm, the adhesive film was peeled from the release PET film. It was sandwiched between silicone sheets and pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 120 minutes, and the obtained film was fixed on a metal disk with a double-sided tape. The surface of the adhesive film that was on the PET side was observed with a tapping mode surface using AFM (manufactured by Bruker axes, Dimension ICON AFM), and the phase separation structure was analyzed by phase imaging. As a result of phase imaging, the area within the range of 0 to 30 when the phase difference is converted to 100 with the smaller phase as 0 and the larger as 100 was determined as “island”, and the other areas as “sea”. .

The abbreviations used in the examples represent the following compounds.
PSX: Diaminosiloxane (weight average molecular weight is 740)
BAPP: 2,2-bis (4-aminophenoxyphenyl) propane N-12: dodecanedioic acid dihydrazide BTDA: 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride K-1: talc (Nippon Talc) Product 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 diameter; 64.9 μm, minimum particle diameter; 0.5 μm, mode diameter; 8.7 μm, cumulative particle amount of particle size of 10 μm or less; 77%, particle diameter of 20 μm Accumulated particle amount above: 5%)

Synthesis Example 1 (Example 1 resin)
In a polymerization vessel, 100 parts by weight of PSX, 10.4 parts by weight of BAPP, 2.2 parts by weight of N-12, 54.4 parts by weight of BTDA, 234 parts by weight of N-methyl-2-pyrrolidone and 156 parts by weight Part of xylene was 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. over 1.5 hours, and heated and stirred as it was for 3.5 hours to obtain a polyimide solution a having completed imidization. The weight average molecular weight (Mw) of the polyimide resin in the obtained polyimide solution a was 119,000.

Synthesis Example 2 (Example 2 resin)
In a polymerization tank, 100 parts by mass of PSX, 10.4 parts by mass of BAPP, 2.2 parts by mass of N-12, 54.4 parts by mass of BTDA, 195 parts by mass of N-methyl-2-pyrrolidone and 195 parts by mass A portion of xylene was charged and mixed well at room temperature for 1 hour. After starting the heating, while gradually adding 54.4 parts by mass of BTDA to this solution in steps, the temperature was raised to 190 ° C. over 8 hours, and the solution was heated and stirred for 23 hours to complete the imidization. Solution b was obtained. The weight average molecular weight (Mw) of the polyimide resin in the obtained polyimide solution b was 84,000.

Synthesis Example 3 (Comparative Example 1 resin)
In a polymerization tank, 100 parts by mass of PSX, 10.4 parts by mass of BAPP, 2.2 parts by mass of N-12, 54.4 parts by mass of BTDA, 195 parts by mass of N-methyl-2-pyrrolidone and 195 parts by mass Part of xylene was 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. over 8 hours, heated and stirred as it was for 23 hours to obtain a polyimide solution c in which imidization was completed. The weight average molecular weight (Mw) of the polyimide resin in the obtained polyimide solution c was 111,000.

Example 1
To 100 parts by mass of the solid part of the polyimide solution a obtained in Synthesis Example 1, 5 parts by mass of N-12 and 10 parts by mass of K-1 were blended, and the polyimide solution 1 was further stirred for 1 hour. Obtained. 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 then covered with a coverlay. Film 1 (adhesive layer thickness; 30 μm) was used. In the flow evaluation using the coverlay film 1, no adhesive flowed out, and there was no problem with solder heat resistance and adhesive strength. The result is shown in FIG.

  Moreover, the polyimide solution 1 was apply | coated to the mold release PET base material, it dried at 80 degreeC for 15 minutes, and it peeled from the mold release PET base material, and produced the polyimide adhesive film 1 (thickness; 30 micrometers). About 10 sheets of this polyimide adhesive film 1 were stacked to prepare a sample having a thickness of about 300 μm, and a rheometer evaluation was performed. As a result, even when the temperature rose to 160 ° C. or higher, no significant decrease in viscosity was observed. The result is shown in FIG.

  Further, the polyimide adhesive film 1 was sandwiched between silicone sheets and pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 120 minutes to obtain an evaluation sample 1. The properties of the obtained film are shown in Table 1.

The AFM observation sample was prepared in the same manner as the evaluation sample 1 except that K-1 was excluded so as not to interfere with the observation. The results of AFM observation are shown in FIG. From Figure 5, the area within the observation region 3600Myuemu ^2, area island region in a range of 20 [mu] m ² or more 140 .mu.m ² or less had a sea-island phase separation structure present one or more. In FIG. 5, the island region is indicated by a white arrow.

Example 2
After obtaining the polyimide solution 2 like Example 1 except having used the polyimide solution b, the coverlay film 2 was obtained. In the flow evaluation using this coverlay film 2, no adhesive flowed out, and there was no problem with solder heat resistance and adhesive strength. The result is shown in FIG.

  Moreover, when rheometer evaluation of the polyimide adhesive film 2 obtained from the polyimide solution 2 was performed like Example 1, even if the temperature rose to 160 degreeC or more, the big viscosity fall was not seen. The result is shown in FIG.

  Further, in the same manner as in Example 1, an evaluation sample 2 was produced from the polyimide adhesive film 2. The characteristics are shown in Table 1.

The AFM observation sample was prepared in the same manner as the evaluation sample 2 except that K-1 was excluded so as not to interfere with the observation. The results of AFM observation are shown in FIG. From Figure 5, the area within the observation region 3600Myuemu ^2, area island region in a range of 20 [mu] m ² or more 140 .mu.m ² or less had a sea-island phase separation structure present one or more. In FIG. 5, the island region is indicated by a white arrow.

Comparative Example 1
After obtaining the polyimide solution 3 like Example 1 except having used the polyimide solution c, the coverlay film 3 was obtained. In the flow evaluation using the coverlay film 3, the adhesive flowed out and the solder heat resistance was lowered. The result is shown in FIG.

  Moreover, when rheometer evaluation of the polyimide adhesive film 3 obtained from the polyimide solution 3 was performed like Example 1, the big viscosity fall was seen from 160 degreeC vicinity. The result is shown in FIG.

  Further, in the same manner as in Example 1, an evaluation sample 3 was produced from the polyimide adhesive film 3. The characteristics are shown in Table 1.

The AFM observation sample was prepared in the same manner as the evaluation sample 3 except that K-1 was excluded so as not to interfere with the observation. The results of AFM observation are shown in FIG. From Figure 5, the area 3600Myuemu ² within the observation region, island region within an area of 20 [mu] m ² or more 140 .mu.m ² less one also absent, did not have a sea-island phase separation structure.

Comparative Example 2
An AFM observation sample was produced in the same manner as in Example 1 except that N-12 in Example 1 was not blended. AFM observation showed that the area 3600Myuemu ² within the observation region, island region within an area of 20 [mu] m ² or more 140 .mu.m ² less one also absent, did not have a sea-island phase separation structure.

  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 (12)

It is obtained by reacting (A) a polyimide having a ketone group and (B) an amino compound having at least two primary amino groups as functional groups, and at least a part of the ketone group in the polyimide has an amino group of the amino compound. Is a cross-linked polyimide resin having a cross-linked structure in which a C═N bond is formed by reaction,
When the phase difference in the phase imaging by atomic force microscope observation is 20 ° or more in the state of being processed into a sheet shape, 0 to 0 when the phase difference is converted to 100 with the smaller phase being 0 and the larger phase being 100. "island" areas in the range of 30, when the other region as "sea", the area 3600Myuemu ² within the observation area, the area is an island region is in the range of 20 [mu] m ² or more 140 .mu.m ² or less A cross-linked polyimide resin having one or more sea-island phase separation structures.   The crosslinked polyimide resin according to claim 1, wherein the sea-island phase separation structure is formed by a crosslinking reaction. The polyimide is a structural unit represented by the following general formulas (1) and (2):

[In the formula, Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic acid anhydride, R ₁ is a divalent diamine residue derived from a diaminosiloxane or an aliphatic diamine compound, and R ₂ is a diamine compound. Each represents a divalent diamine residue derived from Ar, and / or 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 Within the range of 35 to 1.0, n is within the range of 0 to 0.65]
The crosslinked polyimide resin according to claim 1 or 2, which is a polyimide having   The cross-linked polyimide resin according to claim 3, 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 crosslinked polyimide resin according to claim 1, wherein the polyimide 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-shaped inorganic filler in the range whose average particle diameter is 2-25 micrometers is contained in the range of 5-200 weight part with respect to 100 weight part of resin components in any one of Claims 1-6. The crosslinked polyimide resin described. An adhesive resin composition comprising a polyimide having a ketone group and an amino compound having at least two primary amino groups as functional groups,
A cross-linked polyimide resin having a cross-linked structure in which the amino group of the amino compound reacts with at least a part of the ketone group in the polyimide obtained by reacting the polyimide and the amino compound, and a C═N bond is formed. When the phase difference in the phase imaging by atomic force microscope observation is 20 ° or more in the state of being processed into a sheet shape, 0 to 0 when the phase difference is converted to 100 with the smaller phase being 0 and the larger phase being 100. region islands in the range of 30, when the other area with the sea, there area in the observation area 3600Myuemu ^2, island region area is within the range of 20 [mu] m ² or more 140 .mu.m ² or less one or more An adhesive resin composition characterized by having a sea-island phase separation structure.   Hardened | cured material containing the crosslinked polyimide resin of any one of Claims 1-7.   The coverlay film provided with the adhesive bond layer containing the crosslinked polyimide resin of any one of Claims 1-7.   A circuit board comprising the coverlay film according to claim 10. Mixing an acid anhydride component having a ketone group and a diamine component and imidizing by heating to form a polyimide having a ketone group;
The polyimide having the ketone group is reacted with an amino compound having at least two primary amino groups as functional groups, so that at least a part of the ketone group of the polyimide is functionalized with at least two primary amino groups. A method for producing a crosslinked polyimide resin comprising a step of reacting an amino group of an amino compound having a group to form a C═N bond to form a crosslinked structure,
When the cross-linked polyimide resin is processed into a sheet shape and the phase difference in phase imaging by atomic force microscope (AFM) observation is 20 ° or more, the smaller phase is 0 and the larger phase is 100. the "island" regions within 0-30 range when converted into 100, in the case where the other region as "sea", the area 3600Myuemu ² within the observation area, the area is 20 [mu] m ² or more 140 .mu.m ² A method for producing a crosslinked polyimide resin, characterized by having a sea-island phase separation structure in which one or more island regions exist in the following range.