Polyimide precursor-zinc-containing composite composition

Abstract

The present invention provides a material that can significantly improve the adhesion between a copper substrate and a coating of a polyimide resin. [Solution] The present invention comprises: (a) 2 to 20% by mass of a polyimide precursor; (b) 3 to 30 mass% of an alkyl carboxylic acid having 1 to 5 carbon atoms, (c) 3 to 30 mass % of zinc alkyl carboxylate having 1 to 5 carbon atoms, and (d) Solvent 3-90% by mass The polyimide precursor-zinc-containing composite composition further comprises the alkyl carboxylic acid (b) having 1 to 5 carbon atoms, the alkyl carboxylic acid (b) being represented by the chemical formula: R1-COOH (I) (In formula I, R1 represents hydrogen or a linear or branched alkyl group having 1 to 4 carbon atoms which may have an unsaturated bond.) The zinc alkylcarboxylate (c) having 1 to 5 carbon atoms is represented by the chemical formula: (R2-COO)2Zn (II) (In formula II, R2 represents hydrogen or a linear or branched alkyl group having 1 to 4 carbon atoms which may have an unsaturated bond.) It is expressed as:

Description

Technical Field

[0001] The present invention relates to a polyimide precursor-zinc-containing composite composition, particularly a polyimide precursor-zinc-containing composite composition having improved adhesion to copper.

Background Art

[0002] For insulating materials of electronic components, flexible printed circuits (FPCs), films derived from semiconductor devices, surface protective films, and interlayer insulating films, etc., polyamides, polyamide-imides, polyimides, various precursors of polybenzoxazoles, and phenolic resins, etc. are used as thermosetting resins having excellent heat resistance, electrical properties, and mechanical properties. Among them, polyimide resins are typically used, and their precursors are provided in the form of varnishes, and a polyimide film can be easily obtained by coating and performing a baking and drying process. Also, a copper material with low wiring resistance is preferably used for the metal conductor side.

[0003] In recent years, there have been strong demands for miniaturization, thinning, and weight reduction inside electronic devices, and the use environment is severe and higher reliability is required. To obtain high reliability, adhesion between a metal conductor and an insulating substrate, that is, between a copper material and a polyimide resin is required. However, it is known that the adhesion between copper and a polyimide resin is not good, and improvement has been strongly demanded.

[0004] As measures for improvement, there are a method of sputtering a metal onto a resin plate or a method of vacuum depositing a metal, and methods such as plating treatment have been studied for a metal plate. However, these methods have many problems in terms of the working surface, cost, and environmental impact. On the other hand, a method of applying a UV-curable resin composition to a metal surface and UV-curing it or a method of applying a thermosetting resin composition and thermosetting it is considered to be highly advantageous due to the simplicity of the process.

[0005] Various efforts have been made to address the adhesion problem. Japanese Patent Application Laid-Open No. 2024-038631 (Patent Document 1) proposes improving the copper adhesion by blending a silane coupling agent having a succinic acid structure into a photosensitive resin composition. However, in addition to the resins such as polyamide and polyimide and photosensitizers exemplified in Patent Document 1, a photosensitive resin material such as a polyfunctional acrylic compound or an epoxy resin is required to ensure photosensitivity. In these resin systems, there is no heat resistance of 300 °C or higher, and they cannot withstand the baking temperature of the polyimide precursor. Also, in the silane coupling agent and epoxy curing systems, even a slight amount of water content has an adverse effect, so the material conditions are severe and not realistic.

[0006] Japanese Patent Application Laid-Open No. 2024-091579 (Patent Document 2) discloses a photosensitive resin composition containing a polyimide precursor, a photoinitiator, and an allyl group-containing compound having a specific triazole structure. Although it is stated that the copper adhesion can be improved by using this allyl group-containing compound with a special structure, like Patent Document 1, since a photocurable resin is used, the heat resistance is insufficient. Also, particularly the triazole-containing material has a high viscosity, and there are difficulties in workability such as coating.

[0007] Japanese Patent Application Laid-Open No. 2024-070321 (Patent Document 3) discloses an object in which a layer containing a fumed metal oxide and a thermoplastic polyimide resin is attached to a metal foil. Although it is described that this fumed metal compound can improve the adhesion to copper, the fumed metal oxide is in the form of fine particles and easily aggregates, resulting in variations in the adhesion effect, and the process is complicated such as requiring a shearing process for crushing the fumed metal oxide.

[0008] Japanese Patent No. 7492090 (Patent Document 4) proposes that the surface of a copper material is subjected to chromate electrolytic treatment, and further, a silane coupling agent treatment layer is formed as necessary, and an insulating resin substrate (for example, a polyimide resin substrate) is laminated thereon to improve the adhesion to the surface of the copper material. However, since the electrolytic treatment requires an immersion plating process, there are problems of increased man-hours and environmental burden. Therefore, a method with a copper adhesion effect in a simpler process has been demanded.

Prior Art Documents

Patent Document

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0010] The present invention provides a material capable of significantly improving the adhesion between a copper substrate and a polyimide resin film.

Means for Solving the Problems

[0011] That is, the present invention provides the following aspects: [1] (a) 2 - 20% by mass of a polyimide precursor, (b) 3 - 30% by mass of an alkyl carboxylic acid having 1 - 5 carbon atoms, (c) 3 - 30% by mass of zinc alkyl carboxylate having 1 - 5 carbon atoms and (d) 3 - 90% by mass of a solvent A polyimide precursor - zinc - containing composite composition containing the same. [2] The alkyl carboxylic acid (b) having 1 - 5 carbon atoms has the chemical formula: R 1 -COOH (I) (In formula I, R 1 represents hydrogen or a linear or branched alkyl group which may have an unsaturated bond having 1 - 4 carbon atoms.) The polyimide precursor - zinc - containing composite composition according to [1], represented by the formula. [3] The zinc alkyl carboxylate (c) having 1 - 5 carbon atoms has the chemical formula: (R 2-COO) 2 Zn (II) (In formula II, R 2 represents hydrogen or a linear or branched alkyl group which may have an unsaturated bond having 1 to 4 carbon atoms.) The polyimide precursor-zinc-containing composite composition according to [1] or [2], represented by [4] The polyimide precursor-zinc-containing composite composition according to [2], wherein the alkyl carboxylic acid (b) having 1 to 5 carbon atoms is selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, acrylic acid, methacrylic acid, crotonic acid and mixtures thereof. [5] The polyimide precursor-zinc-containing composite composition according to [3], wherein the zinc alkyl carboxylate (c) having 1 to 5 carbon atoms is selected from the group consisting of zinc formate, zinc acetate, zinc propionate, zinc butyrate, zinc isobutyrate, zinc acrylate, zinc methacrylate, zinc crotonate and mixtures thereof. [6] The polyimide precursor-zinc-containing composite composition according to [1], wherein the solvent (d) is selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetramethylurea, γ-butyrolactone and mixtures thereof. [7] The polyimide precursor-zinc-containing composite composition according to [1], wherein the polyimide precursor-zinc-containing composite composition is a one-component composition containing all of the polyimide precursor (a) to the solvent (d). [8] The polyimide precursor-zinc-containing composite composition is the polyimide precursor (a) and a solution composed of the alkyl carboxylic acid (b) having 1 to 5 carbon atoms, the zinc alkyl carboxylate (c) having 1 to 5 carbon atoms and the solvent (d), and The polyimide precursor-zinc-containing composite composition according to [1], which is a two-component composition.

Advantages of the Invention

[0012] The present invention provides a polyimide precursor-zinc-containing composite composition capable of significantly improving the adhesion between the film and a copper substrate. The polyimide precursor-zinc-containing composite composition of the present invention can be prepared by blending zinc alkylcarboxylate without restricting the type of polyimide resin. The film formed from the polyimide precursor-zinc-containing composite composition of the present invention exhibits high adhesion to a copper substrate, improved hardness, and high heat resistance. In addition, the polyimide precursor-zinc-containing composite composition of the present invention can also be overcoated and laminated with another polyimide resin according to the purpose.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described in detail based on preferred embodiments. However, the present invention is not limited to the following embodiments, and various modifications are possible within the scope shown in the claims. In the present invention, the notation "numerical value 1 to numerical value 2" in a numerical range means a range having numerical value 1 as the lower limit value and numerical value 2 as the upper limit value, including both numerical values 1 and 2 at both ends, and is synonymous with "numerical value 1 or more and numerical value 2 or less".

[0014] The polyimide precursor-zinc-containing composite composition of the present invention contains 2 to 20% by mass of a polyimide precursor (a), 3 to 30% by mass of an alkylcarboxylic acid (b) having 1 to 5 carbon atoms, 3 to 30% by mass of zinc alkylcarboxylate (c) having 1 to 5 carbon atoms, and 3 to 90% by mass of a solvent (d). Each component will be described.

[0015] Polyimide precursor (a) The polyimide resin precursor (a) is known to be obtained by mixing a raw material acid dianhydride and diamine in a solvent so as to be substantially equimolar and reacting them. The acid dianhydride is a compound having four carboxylic acid groups, with two of them condensed to form an anhydride. Specifically, examples thereof include pyromellitic dianhydride (PMDA), diphenyl ether-3,3',4,4'-tetracarboxylic dianhydride (ODPA), benzophenone-3,3',4,4'-tetracarboxylic dianhydride (BTDA), biphenyl-3,3',4,4'-tetracarboxylic dianhydride (BPDA), diphenyl sulfone-3,3',4,4'-tetracarboxylic dianhydride (DSDA), diphenylmethane-3,3',4,4'-tetracarboxylic dianhydride, 2,2-bis(3,4-phthalic anhydride)propane, 2,2-bis(3,4-phthalic anhydride)-1,1,1,3,3,3-hexafluoropropane (6FDA), and the like.

[0016] Diamine is an organic compound having two amino groups. Specifically, 3,4'-diaminodiphenyl ether (3,4'-ODA), 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (TFMB), 3,3',5,5'-tetramethylbenzidine, 2,3,5,6-tetramethyl-1,4-phenylenediamine, 3,3'-diaminodiphenyl sulfone, 3,3'-dimethylbenzidine, 3,3'-bis(trifluoromethyl)benzidine, 2,2'-bis(p-aminophenyl)hexafluoropropane, bis(trifluoromethoxy)benzidine (TFMOB), 2,2'-bis(pentafluoroethoxy)benzidine (TFEOB), 2,2'-trifluoromethyl-4,4'-oxydianiline (OBABTF), 2-phenyl-2-trifluoromethyl-bis(p-aminophenyl)methane, 2-phenyl-2-trifluoromethyl-bis(m-aminophenyl)methane, 2,2'-bis(2-heptafluoroisopropoxy-tetrafluoroethoxy)benzidine (DFPOB), 2,2-bis(m-aminophenyl)hexafluoropropane (6-FmDA), 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 3,6-bis(trifluoromethyl)-1,4-diaminobenzene (2TFMPDA), 1-(3,5-diaminophenyl)-2,2-bis(trifluoromethyl)-3,3,4,4,5,5,5-heptafluoropentane, 3,5-diaminobenzotrifluoride (3,5-DABTF), 3,5-diamino-5-(pentafluoroethyl)benzene, 3,5-diamino-5-(heptafluoropropyl)benzene, 2,2'-dimethylbenzidine (DMBZ), 2,2',6,6'-tetramethylbenzidine (TMBZ), 3,6-diamino-9,9-bis(trifluoromethyl)xanthene (6FCDAM), 3,6-diamino-9-trifluoromethyl-9-phenylxanthene (3FCDAM), 3,6-diamino-9,9-diphenylxanthene, etc. can be mentioned.

[0017] Regarding the above acid dianhydride or diamine, it can be freely selected according to the purpose and is not limited thereto. Moreover, these can be used alone, and of course, two or more of them may be mixed and used.

[0018] The polyimide precursor (a) in the polyimide precursor-zinc-containing composite composition of the present invention (hereinafter, sometimes simply referred to as "zinc-containing composite composition") is contained in an amount of 2 to 20% by mass, preferably 3 to 20% by mass, more preferably 4 to 20% by mass, based on the total amount of the zinc-containing composite composition. When the amount of the polyimide precursor (a) is less than 2% by mass, the solid content is small and the strength required for resin formation cannot be obtained. When the blending amount of the polyimide precursor (a) exceeds 20% by mass, the viscosity of the zinc-containing composite composition of the present invention becomes too high and the handleability deteriorates. Regarding the content of the component (a) of the present invention, it means the polyimide precursor component which is the resin solid content, and other contents are not considered.

[0019] Note that the polyimide precursor (a) may be obtained and used as a commercially available product, or may be produced as necessary. Commercially available products are not particularly limited, but for example, products manufactured by various companies such as U-Varnish manufactured by UBE Industries, Ltd., and U-Imide manufactured by Unitika Ltd. can be used. In either commercially available products or synthetic products, any additives, such as antioxidants, viscosity modifiers, and diluting solvents, can be optionally contained from the viewpoints of storage stability and handleability.

[0020] Alkylcarboxylic acid (b) having 1 to 5 carbon atoms The alkylcarboxylic acid (b) having 1 to 5 carbon atoms has the chemical formula (I) R 1 -COOH (I) and is represented by the formula I, in which R 1represents hydrogen or an alkyl group having 1 to 4 carbon atoms, and is an alkyl group having a total carbon number of 1 to 5 including the carbon of the carboxylic acid group. The alkyl group may be linear or branched, and may have an unsaturated bond. Examples of the alkyl carboxylic acid (b) having 1 to 5 carbon atoms include formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, acrylic acid, methacrylic acid, crotonic acid, or a mixture thereof. Regarding the purity of the alkyl carboxylic acid (b) having 1 to 5 carbon atoms, either a water-diluted product or a high-purity product can be used, but preferably those having a purity of 90% or more, preferably 99% or more can be used. Any of them can be used as a commercially available product as it is.

[0021] In the zinc-containing composite composition of the present invention, the alkyl carboxylic acid (b) having 1 to 5 carbon atoms is contained in an amount of 3 to 30% by mass, preferably 3 to 28% by mass, more preferably 3 to 25% by mass. When the blending amount of the alkyl carboxylic acid (b) having 1 to 5 carbon atoms is less than 3% by mass, the polyimide precursor (a) solution is likely to gel and deteriorate, becoming non-uniform and unusable. Also, when it exceeds 30% by mass, the solution is likely to turn white, and the acidity becomes too strong, which becomes a factor for corroding metal substrates such as copper, which is not preferable.

[0022] Zinc alkyl carboxylate (c) having 1 to 5 carbon atoms The zinc alkyl carboxylate (c) having 1 to 5 carbon atoms has the chemical formula II (R 2 -COO) 2 Zn (II) represented by, R 2represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. As the total number of carbon atoms including the carbon atom of the carboxylic acid group, it is an alkyl group having 1 to 5 carbon atoms, which may be linear or branched and may have an unsaturated bond. Examples of zinc alkylcarboxylate (c) having 1 to 5 carbon atoms include zinc formate, zinc acetate, zinc propionate, zinc butyrate, isobutyric acid zinc, zinc acrylate, zinc methacrylate, zinc crotonate, or a mixture thereof. Zinc alkylcarboxylate (c) having 1 to 5 carbon atoms is a salt of a dibasic acid and zinc, and its valence is approximately 2, but may include cases where the width is 1.8 to 2.2. Regarding the purity of zinc alkylcarboxylate (c) having 1 to 5 carbon atoms, those having a purity of preferably 88% or more, more preferably 98% or more exist, and those in the form of hydrates can also be used. Any of them can be used as a commercially available product as it is. Also, zinc alkylcarboxylate (c) having 1 to 5 carbon atoms may be produced by reacting a zinc material with an alkylcarboxylic acid having 1 to 5 carbon atoms. Further, zinc alkylcarboxylate (c) having 1 to 5 carbon atoms may be obtained by reacting an alkali salt of an alkylcarboxylic acid having 1 to 5 carbon atoms with a zinc salt of an inorganic acid. In addition, commercially available zinc acrylate etc. from Asada Chemical Industry Co., Ltd. may be used. These zinc alkylcarboxylates (c) having 1 to 5 carbon atoms may be in the form of lumps, coarse grains, fine powders, or a solution or dispersion, and can be appropriately selected.

[0023] Zinc alkylcarboxylate (c) having 1 to 5 carbon atoms is contained in the zinc-containing composite composition of the present invention in an amount of 3 to 30% by mass, preferably 4 to 30% by mass, more preferably 5 to 30% by mass. When the amount of zinc alkylcarboxylate (c) having 1 to 5 carbon atoms is less than 3% by mass, the effect of copper (plate) adhesion is insufficient, which is not preferable. Also, when it exceeds 30% by mass, the viscosity of the solution of the product of the present invention becomes too high and the handleability deteriorates. The reason for the increase in the adhesion to copper (plate) due to the addition of zinc alkylcarboxylate (c) having 1 to 5 carbon atoms is unknown, but it is predicted to be due to a change in the surface property of the base material due to the affinity between copper and zinc.

[0024] Solvent (d) The solvent (d) incorporated in the zinc-containing composite composition of the present invention may be any that can homogenize the components (a) to (c). Specific examples of the solvent (d) that can be used include polar aprotic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetramethylurea, γ-butyrolactone, and the like. One or more of these can be appropriately selected and used. Regarding the purity of the solvent (d), either industrial products or purified high-purity products can be used, but preferably those with a purity of 99% or more are mentioned. Any of them can be used as commercially available products as they are.

[0025] In the zinc-containing composite composition of the present invention, the solvent (d) is incorporated in an amount of 3 to 90% by mass, preferably 5 to 88% by mass, more preferably 7 to 86% by mass. If the blending amount of the solvent (d) is less than 3% by mass, the various materials cannot be completely dissolved. Conversely, if the blending amount exceeds 90% by mass, the resin solid content is low and the strength required for the formation of the thermosetting resin cannot be obtained.

[0026] Inorganic fillers such as silica, alumina, boron nitride, and silicon nitride may be added to the zinc-containing composite composition of the present invention for the purpose of improving physical properties such as slidability, thermal conductivity, electrical conductivity, and corona resistance. Also, depending on the purpose, thermosetting resins and thermoplastic resins such as polyamide resin, polyamideimide resin, polybenzoxazole resin, their precursors, phenol resin, epoxy resin, and acrylic resin may be used. These can be appropriately selected according to the various properties of the final product.

[0027] Form of the zinc-containing composite composition of the present invention Regarding the form of the zinc-containing composite composition of the present invention, components (a) to (d) are as follows Or <ii>It can be used with any of them. One-component type (a) Polyimide precursor, (b) alkyl carboxylic acid having 1 to 5 carbon atoms, (c) zinc alkyl carboxylate having 1 to 5 carbon atoms, and (d) solvent are all used in one component. <ii>Two-component type The polyimide precursor of component (a) and the solutions of components (b) to (d) are made into two components that can be individually mixed before use.

[0028] The one-component type is a polyimide precursor-zinc-containing composite composition containing all of (a) a polyimide precursor, (b) an alkyl carboxylic acid having 1 to 5 carbon atoms, (c) zinc alkyl carboxylate having 1 to 5 carbon atoms, and (d) a solvent. One <ii>In the two-component type, a composition containing components (b) to (d) can be prepared in advance and added to the (a) polyimide precursor and mixed before use. Whether in the form of one-component or two-component as described above, if the blending amount of each component is outside the scope of the present invention, the zinc-containing composite composition of the present invention will cause severe aggregation, gelation, or white turbidity and become defective. Although the reason is unknown, it is predicted that the presence of a certain amount of alkyl carboxylic acid having 1 to 5 carbon atoms with respect to the acid component or diamine component in the polyimide precursor suppresses the phenomenon of destabilization or aggregation during the introduction of zinc alkyl carboxylate (c).

[0029] When component (b) or component (c) is mixed with the polyimide precursor (a) in the presence of the solvent (d), heat may be generated. The heat generation is preferably at a temperature within the range of 0 to 60°C, more preferably 0 to 50°C. If the temperature during heat generation is less than 0°C, the solubility of zinc carboxylate decreases, which is not preferable. If the temperature during heat generation exceeds 60°C, steam may be generated, or whitening or thickening may occur, which is not preferable. The heat generation during component mixing can also be dealt with by providing a cooling capacity or a cooling process as necessary. Note that pressure control is not required throughout the entire reaction including the heat generation period, and it can be carried out at normal pressure.

[0030] The heat generation reaction time is between 3 minutes and 3 hours and is appropriately set according to the apparatus structure and scale. Moreover, if it is less than 3 minutes, the mixing may be insufficient and fine aggregated particles may remain. If it exceeds 3 hours, it takes time and is uneconomical.

[0031] Note that the zinc-containing composite composition of the present invention is preferably refrigerated and stored at a temperature of 10°C or lower. This is the same as the recommended temperature for storing the raw material polyimide precursor and is due to the fact that it is prone to thickening as the temperature rises. Therefore, refrigerated storage of the zinc-containing composite composition of the present invention is desired. Furthermore, regarding the storage conditions of the zinc-containing composite composition of the present invention, storage in a sealed and moisture-proof environment is preferable. This is the same as the storage of the raw material polyimide precursor, and there is a point to note that it is prone to whitening due to moisture absorption.

[0032] As the manufacturing apparatus for the zinc-containing composite composition of the present invention, a mixer-type stirrer or kneader is preferable. For example, a Banbury mixer, a double-arm kneader, a kneading roll, a planetary mixer, a ribbon blender, a screw blender, etc. can be mentioned, but there is no special limitation and it can be appropriately selected. As the material of these manufacturing apparatuses, it is preferable to use acid-resistant and oil-resistant materials for the liquid contact part. For example, stainless steel of SUS304 or higher, Hastelloy, GL (glass lining), etc. are preferably used. Also, for the seal part of these manufacturing apparatuses, PTFE (polytetrafluoroethylene), fluorine-based copolymer resin, etc. are preferable for the same reason. Further, it is desirable to have a function capable of cooling, such as being jacketed and having external water cooling or being attached to a chiller unit.

[0033] Incidentally, the usage method of the zinc-containing composite composition of the present invention will be outlined below. As the coating target of the zinc-containing composite composition of the present invention, metal substrates such as copper foil and copper plate can be mentioned. For copper foil, electrolytic copper foil or rolled copper foil generally used in applications such as printed wiring boards can be preferably used. The thickness of the copper foil is not particularly restricted, and for example, industrially available ones with a thickness of 1 micron to 70 microns can be used. Also, copper foil whose surface has been roughened or rust-proofed can also be preferably used. Incidentally, depending on the application, it is also possible to use copper plates in the millimeter order as metal plates without any problem.

[0034] As the coating method of the zinc-containing composite composition of the present invention, conventionally used methods such as coating with a spin coater, a bar coater, a blade coater, a curtain coater, a screen printing machine, etc., and spray coating with a spray coater can be used. Regarding the film thickness, there is no special limitation depending on the purpose, but for example, it can be carried out at 1 micron to 60 microns, etc.

[0035] As a film-forming method of the product of the present invention, it can be carried out under the same conditions as the general heat treatment for polyimidization. That is, for example, heat treatment can be carried out at a temperature of 150°C to 400°C for 1 minute to 50 hours to form a film. The temperature and time can be adjusted. For example, after initial vacuum drying or low-temperature treatment (150 to 250°C), film coating can be carried out by this treatment (250 to 400°C), and appropriate selection can be made according to various conditions.

[0036] (Example) The present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

[0037] (Example 1) 1000.0 g of a 20% polyimide precursor (manufactured by UBE Industries, Ltd., U varnish "UPIA A") was charged into a 5 L (liter) planetary mixer, and while stirring, 200.0 g of 99.5% acrylic acid (Fuji Film Wako Pure Chemical Industries, Ltd., reagent special grade) was added to make it uniform. Then, 200.0 g of 98% zinc acrylate (Asada Chemical Industry Co., Ltd., ZDA-100) was added little by little and stirred for 1 hour. Thereafter, 800.0 g of N-methyl-2-pyrrolidone (reagent special grade manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was added little by little as a solvent to make it uniform. The series of temperatures was 25 to 32°C. The component summary was polyimide precursor: 9.1% by mass, acrylic acid: 9.0% by mass, zinc acrylate: 8.9% by mass, solvent (N-methyl-2-pyrrolidone): 36.4% by mass, and the resulting liquid was a uniform and clear yellow viscous liquid.

[0038] (Example 2) Charge 1000.0 g of 20% polyimide precursor into a 5L planetary mixer. While stirring, add 200.0 g of 99.5% acrylic acid to make it uniform, and then add 600.0 g of 98% zinc acrylate little by little and stir for 1 hour. Then, add 2800.0 g of N-methyl-2-pyrrolidone as a solvent little by little to make it uniform. The series of temperatures was 25 - 33°C. The component summary is polyimide precursor: 4.3 mass%, acrylic acid: 4.3 mass%, zinc acrylate: 12.8 mass%, solvent (N-methyl-2-pyrrolidone): 60.9 mass%, and the resulting liquid was a uniform, clear yellow viscous liquid.

[0039] (Example 3) Previously, add 78.5 g of zinc oxide (manufactured by Hakusuitech Co., Ltd., conforming to JIS standard type 2) to 340.5 g of acrylic acid and 781.0 g of N-methyl-2-pyrrolidone in a 2L glass beaker using a hot stirrer, heat to 50°C to dissolve, let it cool, and perform vacuum filtration (filter paper: ADVANTEC, quantitative filter paper No. 5C) to prepare a solution. Charge 1000.0 g of polyimide precursor into a 5L planetary mixer. While stirring, add the prepared solution little by little and stir for 2 hours. The series of temperatures was 25 - 33°C. The component summary is polyimide precursor: 9.2 mass%, acrylic acid: 9.1 mass%, zinc acrylate: 9.0 mass%, solvent (N-methyl-2-pyrrolidone): 35.8 mass%, and the resulting liquid was a uniform, clear yellow viscous liquid.

[0040] (Example 4) Charge 1000.0 g of 20% polyimide precursor into a 5L planetary mixer. While stirring, add 100.0 g of 99.5% formic acid and 100.0 g of 99.5% methacrylic acid thereto to make it uniform. Then, add 200.0 g of 98% zinc acrylate little by little and stir for 1 hour. Thereafter, add 800.0 g of N-methyl-2-pyrrolidone as a solvent little by little to make it uniform. The series of temperatures was 25 - 33°C. The component summary is polyimide precursor: 9.1 mass%, alkyl carboxylic acid having 1 - 5 carbon atoms (formic acid and methacrylic acid): 9.0 mass%, zinc acrylate: 8.9 mass%, solvent (N-methyl-2-pyrrolidone): 36.4 mass%, and the resulting liquid was a uniform, clear yellow viscous liquid.

[0041] (Example 5) Charge 1000.0 g of 20% polyimide precursor into a 5L planetary mixer. While stirring, add 200.0 g of 99.5% acrylic acid thereto to make it uniform. Then, add 200.0 g of 98% zinc formate little by little and stir for 2 hours. Thereafter, add 800.0 g of N,N-dimethylacetamide as a solvent little by little to make it uniform. The series of temperatures was 25 - 32°C. The component summary is polyimide precursor: 9.1 mass%, carboxylic acid (acrylic acid): 9.0 mass%, zinc carboxylate (zinc formate): 8.9 mass%, solvent (N,N-dimethylacetamide): 36.4 mass%, and the resulting liquid was a uniform, clear yellow viscous liquid.

[0042] (Comparative Example 1) Previously charge 200.0 g of 98% zinc acrylate and 800.0 g of N-methyl-2-pyrrolidone into a 2L glass beaker using a hot stirrer, heat to 50°C to dissolve and then let cool, and perform vacuum filtration (filter paper: ADVANTEC, quantitative filter paper No. 5C) to prepare an adjustment solution. Charge 1000.0 g of polyimide precursor into a 5L planetary mixer. While stirring, when the above adjustment solution was added thereto, significant gelation occurred and it separated from the solvent and solidified. The series of temperatures was 25 - 30°C. A uniform solution could not be obtained as the zinc-containing resin composition of the present invention.

[0043] (Comparative Example 2) Previously, 1000.0 g of 99.5% acrylic acid, 200.0 g of 98% zinc acrylate, and 800.0 g of N-methyl-2-pyrrolidone were charged into a 3 L glass beaker using a hot stirrer, heated to 50 °C for dissolution, allowed to cool, and vacuum filtered (filter paper: ADVANTEC, quantitative filter paper No. 5C) to prepare a solution. 1000.0 g of a polyimide precursor was charged into a 5 L planetary mixer, and while stirring, the prepared solution was added thereto, at which point it turned white and gelled. The series of temperatures was 25 - 34 °C. A uniform solution could not be obtained as the zinc-containing resin composition of the present invention.

[0044] (Comparative Example 3) 1000.0 g of a polyimide precursor was charged into a 5 L planetary mixer, and while stirring, 200.0 g of acrylic acid was added thereto to make it uniform. Then, when 400.0 g of a 43% zinc 2-ethylhexanoate·mineral spirit solution (Fuji Film Wako Pure Chemical Industries, Ltd.) was added little by little, it significantly gelled, separated from the solvent, and solidified. The series of temperatures was 25 - 35 °C. A uniform solution could not be obtained as the zinc-containing resin composition of the present invention.

[0045] (Comparative Example 4) 1000.0 g of a polyimide precursor was charged into a 5 L planetary mixer, and while stirring, 200.0 g of 99.5% acrylic acid was added thereto to make it uniform. Then, 50.0 g of 98% zinc acrylate was added little by little and stirred for 1 hour. Thereafter, 950.0 g of N-methyl-2-pyrrolidone was added little by little as a solvent to make it uniform. The series of temperatures was 25 - 34 °C. The component summary was polyimide precursor: 9.1 mass%, carboxylic acid: 9.0 mass%, zinc carboxylate: 2.2 mass%, solvent: 43.2 mass%, and the obtained liquid was a uniform, clear yellow viscous liquid.

[0046] As the material components and information obtained in the examples and comparative examples, the blending ratios of various materials are shown in Table 1. The evaluation of the appearance is described in Table 1. The "appearance" was evaluated as follows.

[0047] [Appearance] The liquidity after synthesis was visually observed for appearance. 〇: Uniform solution state ×: Heterogeneous, non-fluid, or solid

[0048] (Reference Example) A solution was prepared by adding 1200.0 g of N-methyl-2-pyrrolidone to 1000.0 g of the 20% polyimide precursor (manufactured by UBE Industries, Ltd., U varnish "Yupia A") used in the examples, diluting, and mixing uniformly.

[0049] (Comparative Example 5) A solution was prepared by adding 113.6 g of a silane coupling agent treatment solution (a mixture of 26.0 g of 3-trimethoxysilylpropyl succinic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.), 52.0 g of N-methyl-2-pyrrolidone, and 35.6 g of distilled water stirred with a magnetic stirrer at room temperature for 16 hours) to 1000.0 g of the polyimide precursor of the 20% polyimide precursor (manufactured by UBE Industries, Ltd., U varnish "Yupia A") used in the examples, and mixing uniformly.

[0050] The solutions obtained in Examples 1 to 5, Comparative Examples 4 to 5, and the reference example were applied to a copper plate (rolled copper plate HC0366 manufactured by AS ONE Corporation), heat-treated by baking, and the results of various evaluations of the films produced are shown in Table 2.

[0051] The explanations of various evaluation items are described below. Note that JIS K5600-5-6 (Adhesion - Cross-Cut Method) examines the influence particularly affected by the adhesion to either the undercoat or the substrate among various factors, and was used to see the qualitative standard of the adhesion to the substrate.

[0052] [Adhesion] Performed in accordance with JIS K5600-5-6 (Adhesion - Cross-Cut Method). Evaluation ○: Indicates the best score [0 points]. △: Indicates medium level [3 points]. ×: Indicates the lowest score [5 points].

[0053] [Heat-resistant Adhesion] After standing in a constant-temperature dryer at 400°C for 20 minutes, the same test as the above adhesion test was performed. Evaluation ○: Indicates the best point [0 points]. △: Indicates medium level [3 points]. ×: Indicates the lowest point [5 points].

[0054] [EDX] Shows the weight ratio of zinc by energy dispersive X-ray spectroscopy. The weight ratio of zinc is the weight % of zinc among all the elements detected by energy dispersive X-ray spectroscopy on the film surface.

[0055] [Pencil hardness] Performed in accordance with JIS K5600-5-4 (Mechanical properties of coatings - Scratch hardness (pencil method)).

[0056]

Table 1

[0057]

Table 2

[0058] As shown in Table 1, in Examples 1 to 5 and Comparative Example 4, a uniform solution could be obtained. On the other hand, in Comparative Example 1, since the alkylcarboxylic acid (b) having 1 to 5 carbon atoms was not used, a uniform solution as a zinc-containing composite composition could not be obtained. Also, in Comparative Example 2, since the blending amount of the alkylcarboxylic acid (b) having 1 to 5 carbon atoms was large, a uniform solution as a zinc-containing composite composition could not be obtained. In Comparative Example 3, zinc 2-ethylhexanoate having 9 carbon atoms was used as the zinc alkylcarboxylate (c), resulting in non-uniformity and being defective. Comparative Example 4 is an example where the blending amount of the zinc alkylcarboxylate (c) having 1 to 5 carbon atoms is small, but the appearance at the mixing time is not inferior.

[0059] As shown in Table 2, the films using Examples 1 to 5 had extremely good adhesion to copper and heat-resistant adhesion. The reference example was a single film made of a polyimide precursor, and had poor adhesion to copper. Also, in Comparative Example 4, the blending amount of zinc alkylcarboxylate (c) having 1 to 5 carbon atoms was small as described above, and the adhesion to copper was slightly poor (medium). Comparative Example 5 was a silane coupling agent formulation used in the prior art, but the adhesion to copper was poor. In addition, it was confirmed that the surface hardness of the films of Examples 1 to 5 was also significantly improved compared to the reference example.

[0060] Within the scope described in the present invention, the adhesion to a copper substrate and the heat-resistant adhesion could be significantly improved, and various effectivenesses could be confirmed.

[0061] The present invention provides a zinc-containing composite composition capable of significantly improving the adhesion between a copper substrate and a polyimide resin film.

Industrial Applicability

[0062] The polyimide precursor-zinc-containing composite composition of the present invention gives an effect of significantly improving the adhesion to a copper substrate and a thermosetting resin such as a polyimide resin, which has been a conventional problem. In recent years, in the fields of insulating films, heat-resistant adhesion, laminates, etc. of electronic components, further high-functionalization is expected to accelerate in the future, and improving the adhesion between a metal conductor and an insulator can be greatly utilized industrially. Further applications as functional materials are expected in other fields in the future.

[0063] Add the following aspects of the invention: [1] (a) 2 to 20% by mass of a polyimide precursor, (b) 3 to 30% by mass of an alkylcarboxylic acid having 1 to 5 carbon atoms, (c) 3 to 30% by mass of zinc alkylcarboxylate having 1 to 5 carbon atoms and (d) 3 to 90% by mass of a solvent A polyimide precursor-zinc-containing composite composition containing the same. [2] The alkylcarboxylic acid (b) having 1 to 5 carbon atoms has the chemical formula: R 1 -COOH (I) (In formula (I), R 1 represents hydrogen or a linear or branched alkyl group which may have an unsaturated bond and has 1 to 4 carbon atoms.) The polyimide precursor-zinc-containing composite composition according to [1], represented by [3] The zinc alkyl carboxylate (c) having 1 to 5 carbon atoms has the chemical formula: (R 2 -COO) 2 Zn (II) (In formula (II), R 2 represents hydrogen or a linear or branched alkyl group which may have an unsaturated bond and has 1 to 4 carbon atoms.) The polyimide precursor-zinc-containing composite composition according to [1] or [2], represented by [4] The polyimide precursor-zinc-containing composite composition according to any one of [1] to [3], wherein the alkyl carboxylic acid (b) having 1 to 5 carbon atoms is selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, acrylic acid, methacrylic acid, crotonic acid and mixtures thereof. [5] The polyimide precursor-zinc-containing composite composition according to any one of [1] to [4], wherein the zinc alkyl carboxylate (c) having 1 to 5 carbon atoms is selected from the group consisting of zinc formate, zinc acetate, zinc propionate, zinc butyrate, zinc isobutyrate, zinc acrylate, zinc methacrylate, zinc crotonate and mixtures thereof. [6] The polyimide precursor-zinc-containing composite composition according to any one of [1] to [5], wherein the solvent (d) is selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetramethylurea, γ-butyrolactone and mixtures thereof. [7] The polyimide precursor-zinc-containing composite composition according to any one of [1] to [6], wherein the polyimide precursor-zinc-containing composite composition is a one-component composition containing all of the polyimide precursor (a) to the solvent (d). [8] The polyimide precursor-zinc-containing composite composition is composed of the polyimide precursor (a) and a solution composed of the alkylcarboxylic acid (b) having 1 to 5 carbon atoms, zinc alkylcarboxylate (c) having 1 to 5 carbon atoms, and the solvent (d), and is a two-component composition according to any one of [1] to [7].< / ii> < / ii> < / ii>

Claims

1. (a) 2 to 20% by mass of a polyimide precursor, (b) 3 to 30% by mass of an alkyl carboxylic acid having 1 to 5 carbon atoms, (c) 3 to 30% by mass of a zinc alkyl carboxylate having 1 to 5 carbon atoms, and (d) Solvent 3-90% by mass A polyimide precursor-zinc-containing composite composition comprising:

2. The alkyl carboxylic acid (b) having 1 to 5 carbon atoms is represented by the chemical formula: R １ -COOH (I) (In formula I, R １ represents hydrogen or a straight-chain or branched-chain alkyl group having 1 to 4 carbon atoms which may have an unsaturated bond. The polyimide precursor-zinc-containing composite composition according to claim 1,

3. The zinc alkylcarboxylate (c) having 1 to 5 carbon atoms has the chemical formula: (R ２ -COO) ２ Zn (II) (In formula II, R ２ represents hydrogen or a straight-chain or branched-chain alkyl group having 1 to 4 carbon atoms which may have an unsaturated bond.

3. The polyimide precursor-zinc-containing composite composition according to claim 1 or 2, wherein the polyimide precursor-zinc-containing composite composition is represented by the formula:

4. 3. The polyimide precursor-zinc-containing composite composition according to claim 2, wherein the alkyl carboxylic acid (b) having 1 to 5 carbon atoms is selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, acrylic acid, methacrylic acid, crotonic acid, and mixtures thereof.

5. 4. The polyimide precursor-zinc-containing composite composition according to claim 3, wherein the zinc alkylcarboxylate (c) having 1 to 5 carbon atoms is selected from the group consisting of zinc formate, zinc acetate, zinc propionate, zinc butyrate, zinc isobutyrate, zinc acrylate, zinc methacrylate, zinc crotonate, and mixtures thereof.

6. The polyimide precursor-zinc-containing composite composition according to claim 1, wherein the solvent (d) is selected from the group consisting of N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, tetramethylurea, γ-butyrolactone, and mixtures thereof.

7. The polyimide precursor-zinc-containing composite composition according to claim 1, wherein the polyimide precursor-zinc-containing composite composition is a one-liquid composition containing all of the polyimide precursor (a) to the solvent (d).

8. The polyimide precursor (a), a solution comprising the alkyl carboxylic acid having 1 to 5 carbon atoms (b), the zinc alkyl carboxylate having 1 to 5 carbon atoms (c), and the solvent (d); The two-liquid composition for producing a polyimide precursor-zinc-containing composite composition according to claim 1, comprising:

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