Polyimide precursor-zinc-containing composite composition

Abstract

The present invention provides a material capable of significantly improving the adhesion between the film of a copper base material and a polyimide resin. 【Solution means】 The present invention provides a polyimide precursor-zinc-containing composite composition containing (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 zinc alkyl carboxylate having 1 to 5 carbon atoms, and (d) 3 to 90% by mass of a solvent. The alkyl carboxylic acid (b) having 1 to 5 carbon atoms has the chemical formula: R1-COOH (I) (In formula I, R1 represents hydrogen or a linear or branched alkyl group which may have an unsaturated bond having 1 to 4 carbon atoms.) and is represented by, and the zinc alkyl carboxylate (c) having 1 to 5 carbon atoms has the chemical formula: (R2-COO)2Zn (II) (In formula II, R2 represents hydrogen or a linear or branched alkyl group which may have an unsaturated bond having 1 to 4 carbon atoms.) and is represented by.

Description

Technical Field

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

Background Art

[0002] For insulating materials of electronic components, flexible printed boards (FPCs), films derived from semiconductor devices, surface protection 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 on the metal conductor side.

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

[0004] As efforts for improvement, there are methods of sputtering metal onto a resin plate or vacuum-depositing metal, and methods such as plating treatment have been studied for metal plates. 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 the metal surface and performing UV curing or a method of applying a thermosetting resin composition and performing thermosetting 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 Publication No. 2024-038631 (Patent Document 1) proposes improving copper adhesion by incorporating a silane coupling agent having a succinic acid structure into a photosensitive resin composition. However, in addition to the resins and photosensitive agents such as polyamide and polyimide exemplified in Patent Document 1, a photosensitive resin material such as a polyfunctional acrylic compound or epoxy resin is required to ensure photosensitivity. These resin systems do not have heat resistance above 300°C and cannot withstand the curing temperature of the polyimide precursor. Furthermore, even a small amount of water content negatively affects silane coupling agents and epoxy curing systems, making the material conditions too stringent and impractical.

[0006] Japanese Patent Publication No. 2024-091579 (Patent Document 2) discloses a photosensitive resin composition containing a polyimide precursor, a photopolymerization initiator, and an allyl group-containing compound having a specific triazole structure. It is stated that copper adhesion can be improved using this allyl group-containing compound with a special structure, but, similar to Patent Document 1, it lacks heat resistance because it uses a photocurable resin. In addition, the triazole-containing material has particularly high viscosity, making it difficult to work with in applications such as coating.

[0007] Japanese Patent Publication No. 2024-070321 (Patent Document 3) discloses a material in which a layer containing a fumed metal oxide and a thermoplastic polyimide resin is attached to a metal foil. It is stated that this fumed metal compound can improve adhesion to copper, but the fumed metal oxide is in the form of fine particles and tends to aggregate, resulting in inconsistent adhesion effects, and the process is complicated, requiring shearing treatment to break down the fumed metal oxide.

[0008] Japanese Patent No. 7492090 (Patent Document 4) proposes that the adhesion to the copper material surface can be improved by chromate electrolytic treatment of the copper material surface, and further forming a silane coupling agent treatment layer as needed, and then laminating an insulating resin substrate (for example, a polyimide resin substrate) on top of it. However, since the electrolytic treatment requires an immersion plating process, there are undesirable issues in terms of increased man-hours and environmental impact. Therefore, there has been a need for a simpler method that provides an effective copper adhesion method. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2024-38631 [Patent Document 2] Japanese Patent Publication No. 2024-91579 [Patent Document 3] Japanese Patent Publication No. 2024-70321 [Patent Document 4] Patent No. 7492090 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] This invention provides a material that can significantly improve the adhesion between a copper substrate and a polyimide resin coating. [Means for solving the problem]

[0011] In other words, the present invention provides the following aspects: [1] (a) Polyimide precursor 2-20% by mass, (b) 3-30% by mass of alkylcarboxylic acid having 1-5 carbon atoms, (c) 3 to 30% by mass of zinc alkylcarboxylate having 1 to 5 carbon atoms and (d) Solvent 3-90% by mass A polyimide precursor-zinc-containing composite composition containing the following: [2] The aforementioned alkylcarboxylic acid (b) having 1 to 5 carbon atoms has the chemical formula: R1-COOH (I) (In formula I, R1 represents a linear or branched alkyl group which may have hydrogen or an unsaturated bond having 1 to 4 carbon atoms.) A polyimide precursor-zinc-containing composite composition as described in [1], represented by [1]. [3] The aforementioned zinc alkylcarboxylate (c) having 1 to 5 carbon atoms has the chemical formula: (R2-COO)2Zn (II) (In formula II, R2 represents a linear or branched alkyl group which may have hydrogen or an unsaturated bond having 1 to 4 carbon atoms.) A polyimide precursor-zinc-containing composite composition represented by [1] or [2]. [4] The polyimide precursor-zinc-containing composite composition according to [2], wherein the alkylcarboxylic 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 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 [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-liquid composition containing all of the polyimide precursors (a) to the solvent (d). [8] The aforementioned polyimide precursor-zinc-containing composite composition The polyimide precursor (a) and A solution comprising the C1-C5 alkylcarboxylic acid (b), the C1-C5 zinc alkylcarboxylic acid (c), and the solvent (d), The polyimide precursor-zinc-containing composite composition according to [1] is a two-component composition comprising the following components. [Effects of the Invention]

[0012] The present invention provides a polyimide precursor-zinc-containing composite composition that can significantly improve the adhesion between the film and a copper substrate-polyimide resin. The polyimide precursor-zinc-containing composite composition of the present invention can be prepared by blending zinc alkyl carboxylate 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 with numerical value 1 as the lower limit value and numerical value 2 as the upper limit value, including both numerical values 1 and numerical value 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 alkyl carboxylic acid (b) having 1 to 5 carbon atoms, 3 to 30% by mass of zinc alkyl carboxylate (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) It is known that polyimide resin precursor (a) can be obtained by mixing the raw material acidic dianhydride and diamine in a solvent in substantially equimolar amounts and reacting them. Acidic dianhydride is a compound that has four carboxylic acid groups, two of which are condensed together to form an anhydride. Specifically, examples include pyromellitic anhydride (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, and 2,2-bis(3,4-phthalic anhydride)-1,1,1,3,3,3-hexafluoropropane (6FDA).

[0016] Diamines are organic compounds containing 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, and 2-phenyl-2-trif Luoromethyl-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 Examples include 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), and 3,6-diamino-9,9-diphenylxanthene.

[0017] The above-mentioned acidic dianhydrides or diamines can be freely selected depending on the purpose, and are not limited to these. Furthermore, they can be used individually, or two or more may be used in combination.

[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 present in an amount of 2 to 20% by mass, preferably 3 to 20% by mass, and more preferably 4 to 20% by mass, based on the total amount of the zinc-containing composite composition. If the amount of polyimide precursor (a) is less than 2% by mass, the solid content will be low, and the strength required for resin formation will not be obtained. If the amount of polyimide precursor (a) exceeds 20% by mass, the viscosity of the zinc-containing composite composition of the present invention will become too high, making it difficult to handle. The content of component (a) of the present invention refers to the polyimide precursor portion which is the resin solid content, and other components are not considered.

[0019] The polyimide precursor (a) may be obtained from a commercial product or manufactured as needed. There are no particular restrictions on the commercial product, but products from various companies such as U-Varnish from UBE Corporation and U-Imide from Unitika Ltd. can be used. In either the commercial product or the synthetic product, any additives, such as antioxidants, viscosity modifiers, and diluents, may be optionally included from the viewpoint of preservation and handling.

[0020] Alkylcarboxylic acids with 1 to 5 carbon atoms (b) Alkylcarboxylic acids (b) having 1 to 5 carbon atoms have chemical formula (I) R1-COOH (I) This is expressed as follows, where R1 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, and the alkyl group has a total of 1 to 5 carbon atoms including the carbon atoms of the carboxylic acid group. The alkyl group may be linear or branched, and may have unsaturated bonds. Examples of alkylcarboxylic acids (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 mixtures thereof. Regarding the purity of alkylcarboxylic acids (b) having 1 to 5 carbon atoms, both water-diluted and high-purity products can be used, but preferably products with a purity of 90% or higher, and preferably 99% or higher, can be used. Commercial products can be used as is.

[0021] In the zinc-containing composite composition of the present invention, the alkylcarboxylic 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, and more preferably 3 to 25% by mass. If the amount of alkylcarboxylic acid (b) having 1 to 5 carbon atoms is less than 3% by mass, the polyimide precursor (a) solution is prone to gelation degradation, becomes non-uniform, and is unusable. If it exceeds 30% by mass, the solution is prone to whitening, and the acidity becomes too strong, which is undesirable as it can corrode metal substrates such as copper.

[0022] Zinc alkylcarboxylates with 1 to 5 carbon atoms (c) Zinc alkylcarboxylates (c) having 1 to 5 carbon atoms are classified under chemical formula II (R2-COO)2Zn (II) Represented as , where R2 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, and the total number of carbon atoms, including the carbon atoms of the carboxylic acid group, is 1 to 5, and it may have unsaturated bonds regardless of whether it is a linear or branched chain. Examples of zinc alkylcarboxylates having 1 to 5 carbon atoms include zinc formate, zinc acetate, zinc propionate, zinc butyrate, zinc isobutyrate, zinc acrylate, zinc methacrylate, zinc crotonate, or mixtures thereof. Zinc alkylcarboxylates having 1 to 5 carbon atoms are salts of zinc of dibasic acids, and their valency is approximately 2, but may include cases with an equivalence of 1.8 to 2.2. Regarding the purity of zinc alkylcarboxylates having 1 to 5 carbon atoms, preferably a purity of 88% or higher, and more preferably a purity of 98% or higher, and hydrated forms are also available. Commercial products can be used as is. Alternatively, zinc alkylcarboxylates having 1 to 5 carbon atoms may be produced by reacting a zinc material with an alkylcarboxylic acid having 1 to 5 carbon atoms. Furthermore, zinc(c) alkylcarboxylates 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. Alternatively, commercially available zinc acrylates from Asada Chemical Industries, Ltd. may be used. These zinc(c) alkylcarboxylates having 1 to 5 carbon atoms may be in the form of lumps, coarse granules, fine powders, solutions, or dispersions, and can be selected as appropriate.

[0023] Zinc alkylcarboxylate (C) having 1 to 5 carbon atoms is included 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, and more preferably 5 to 30% by mass. If the amount of zinc alkylcarboxylate (C) having 1 to 5 carbon atoms is less than 3% by mass, the effect of improving adhesion to copper (plate) is insufficient and undesirable. If it exceeds 30% by mass, the viscosity of the solution of the present invention becomes too high, making it difficult to handle. The reason why the addition of zinc alkylcarboxylate (C) having 1 to 5 carbon atoms improves adhesion to copper (plate) is unknown, but it is predicted to be due to a change in the surface properties of the substrate due to the affinity between copper and zinc.

[0024] Solvent (d) The solvent (d) incorporated into the zinc-containing composite composition of the present invention may be any solvent that homogenizes components (a) to (c). Specific examples of usable solvents (d) include polar aprotic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, tetramethylurea, and γ-butyrolactone. One or more of these can be appropriately selected and used. Regarding the purity of solvent (d), both industrial products and purified high-purity products can be used, but those with a purity of 99% or higher are preferred. Commercially available products can be used as is.

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

[0026] The zinc-containing composite composition of the present invention may contain inorganic fillers such as silica, alumina, boron nitride, and silicon nitride to improve physical properties such as sliding properties, thermal conductivity, electrical conductivity, and corona resistance. Furthermore, depending on the purpose, thermosetting resins and thermoplastic resins such as polyamide resins, polyamide-imide resins, polybenzoxazole resins, their precursors, phenolic resins, epoxy resins, and acrylic resins may be used. These can be appropriately selected according to the characteristics of the final product.

[0027] Form of the zinc-containing composite composition of the present invention The form of the zinc-containing composite composition of the present invention is as follows, with components (a) to (d) being: or <ii>It can be used in either case. One-component type It is used as a single solution containing (a) a polyimide precursor, (b) an alkyl carboxylic acid having 1 to 5 carbon atoms, (c) zinc alkyl carboxylic acid having 1 to 5 carbon atoms, and (d) a solvent. <ii>two-component type The polyimide precursor of component (a) and the solutions of components (b) to (d) are kept separate and can be mixed before use to form two liquids.

[0028] The one-component type is a polyimide precursor-zinc-containing composite composition that includes all of (a) to (d) of (a) a polyimide precursor, (b) an alkyl carboxylic acid having 1 to 5 carbon atoms, (c) a zinc alkyl carboxylic acid having 1 to 5 carbon atoms, and (d) a solvent. <ii>In the two-component form, a composition containing components (b) to (d) can be prepared in advance and added to the polyimide precursor (a) and mixed before use. Even in the form of one or two components as described above, if the amount of each component is outside the range of the present invention, the zinc-containing composite composition of the present invention will be unsatisfactory due to severe aggregation, gelation, and turbidity. The reason is unknown, but it is predicted that the presence of a certain amount of C1-C5 alkylcarboxylic acid relative to the acid component or diamine component in the polyimide precursor suppresses the phenomenon of instability and aggregation when zinc alkylcarboxylic acid (c) with C1-C5 is introduced.

[0029] When component (b) or component (c) is mixed with polyimide precursor (a) in the presence of solvent (d), exothermic reaction may occur. The exothermic reaction is preferably in the range of 0 to 60°C, and more preferably in the range of 0 to 50°C. If the temperature during exothermic reaction is below 0°C, the solubility of zinc carboxylate decreases, which is undesirable. If the temperature during exothermic reaction exceeds 60°C, vapor may be generated, or whitening or thickening may occur, which is undesirable. The exothermic reaction during component mixing can be addressed as needed by providing a cooling capacity or cooling step. Pressure control is not necessary throughout the entire reaction, including the exothermic reaction, and the reaction can be carried out at atmospheric pressure.

[0030] The exothermic reaction time is between 3 minutes and 3 hours, and should be set appropriately depending on the apparatus structure and scale. If the reaction time is less than 3 minutes, mixing may be insufficient, and fine aggregated particles may remain. Conversely, exceeding 3 hours is time-consuming and uneconomical.

[0031] Furthermore, the zinc-containing composite composition of the present invention is preferably stored refrigerated at a temperature of 10°C or below. This is equivalent to the recommended storage temperature for the raw material polyimide precursor, and is due to the tendency for the composition to thicken with increasing temperature. Therefore, refrigeration is desirable for the zinc-containing composite composition of the present invention. In addition, storage conditions for the zinc-containing composite composition of the present invention are preferably in a sealed, moisture-free environment. This is equivalent to the storage conditions for the raw material polyimide precursor, and it is important to note that it is prone to whitening due to moisture absorption.

[0032] As a manufacturing apparatus for the zinc-containing composite composition of the present invention, a mixer-type agitator or kneader is preferred. Examples include Banbury mixers, double-arm kneaders, kneading rolls, planetary mixers, ribbon blenders, screw blenders, etc., but there are no particular limitations and they can be selected as appropriate. For the wetted parts of these manufacturing apparatuses, it is preferable to use materials that are resistant to acids and oils, such as stainless steel of SUS304 or higher, Hastelloy, GL (glass lining), etc. For the same reasons, PTFE (polytetrafluoroethylene), fluorine copolymer resin, etc. are preferred for the sealing parts of these manufacturing apparatuses. It is also desirable that the apparatuses have a cooling function, such as being jacketed and having external water cooling or a chiller unit attached.

[0033] The method of using the zinc-containing composite composition of the present invention is outlined below. Suitable coating targets for the zinc-containing composite composition of the present invention include metal substrates such as copper foil and copper plates. For copper foil, electrolytic copper foil or rolled copper foil, commonly used in applications such as printed circuit boards, are preferably used. There are no particular restrictions on the thickness of the copper foil; for example, industrially available foils with thicknesses ranging from 1 to 70 microns can be used. Copper foils with surface roughening or rust-preventive treatments are also preferably used. Furthermore, depending on the application, copper plates on the millimeter order can be used without any problems.

[0034] Conventional coating methods for the zinc-containing composite composition of the present invention can be used, such as coating with a spin coater, bar coater, blade coater, curtain coater, screen printing machine, or spray coating with a spray coater. There are no particular restrictions on the film thickness depending on the purpose, but it can be applied with a thickness of, for example, 1 micron to 60 microns.

[0035] The present invention can be used to form a film under conditions similar to those for general polyimide heat treatment. That is, for example, a film can be formed by heat treatment at a temperature of 150°C to 400°C for 1 minute to 50 hours. The temperature and time can be adjusted, and can be appropriately selected according to various conditions, for example, by first performing vacuum drying or low-temperature treatment (150 to 250°C) before the main treatment (250 to 400°C) to form a coating.

[0036] (Examples) 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) 1000.0g of 20% polyimide precursor (UBE, U-Varnish "Yupia A") was charged into a 5L planetary mixer. While stirring, 200.0g of 99.5% acrylic acid (Fujifilm Wako Pure Chemical Industries, reagent grade) was added and mixed until homogenized. Then, 200.0g of 98% zinc acrylate (Asada Chemical Industries, ZDA-100) was added in small increments and stirred for 1 hour. After that, 800.0g of N-methyl-2-pyrrolidone (Fujifilm Wako Pure Chemical Industries, reagent grade) was added in small increments as a solvent and mixed until homogenized. The temperature throughout the process was 25-32°C. The composition was as follows: 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. The resulting liquid was a homogeneous, clear, yellowish viscous liquid.

[0038] (Example 2) 1000.0g of 20% polyimide precursor was placed in a 5L planetary mixer and stirred. 200.0g of 99.5% acrylic acid was added and mixed until homogenized. Then, 600.0g of 98% zinc acrylate was added in small increments while stirring for 1 hour. Subsequently, 2800.0g of N-methyl-2-pyrrolidone was added in small increments as a solvent and mixed until homogenized. The temperature throughout the process was 25-33°C. The composition was approximately polyimide precursor: 4.3% by mass, acrylic acid: 4.3% by mass, zinc acrylate: 12.8% by mass, solvent (N-methyl-2-pyrrolidone): 60.9% by mass. The resulting liquid was a homogeneous, clear, yellowish viscous liquid.

[0039] (Example 3) In advance, 340.5g of acrylic acid, 781.0g of N-methyl-2-pyrrolidone, and 78.5g of zinc oxide (manufactured by Hakusui Tech Co., Ltd., conforming to JIS standard type 2) were added to a 2L glass beaker using a hot stirrer, heated to 50°C to dissolve, allowed to cool, and then vacuum filtered (using ADVANTEC quantitative filter paper No. 5C) to prepare the solution. 1000.0g of polyimide precursor was placed in a 5L planetary mixer, and while stirring, the prepared solution was added in small amounts and stirred for 2 hours. The temperature throughout the process was 25-33°C. The composition was as follows: polyimide precursor: 9.2% by mass, acrylic acid: 9.1% by mass, zinc acrylate: 9.0% by mass, solvent (N-methyl-2-pyrrolidone): 35.8% by mass. The resulting liquid was a homogeneous, clear, yellowish viscous liquid.

[0040] (Example 4) 1000.0g of 20% polyimide precursor was placed in a 5L planetary mixer and, while stirring, 100.0g of 99.5% formic acid and 100.0g of 99.5% methacrylic acid were added and mixed until homogenized. Then, 200.0g of 98% zinc acrylate was added in small increments and stirred for 1 hour. After that, 800.0g of N-methyl-2-pyrrolidone was added in small increments as a solvent and mixed until homogenized. The temperature throughout the process was 25-33°C. The composition was as follows: polyimide precursor: 9.1% by mass, alkyl carboxylic acids with 1-5 carbon atoms (formic acid and methacrylic acid): 9.0% by mass, zinc acrylate: 8.9% by mass, solvent (N-methyl-2-pyrrolidone): 36.4% by mass. The resulting liquid was a homogeneous, clear, yellowish viscous liquid.

[0041] (Example 5) 1000.0g of 20% polyimide precursor was placed in a 5L planetary mixer and stirred. 200.0g of 99.5% acrylic acid was added and mixed until homogenized. Then, 200.0g of 98% zinc formate was added in small increments while stirring for 2 hours. After that, 800.0g of N,N-dimethylacetamide was added in small increments as a solvent and mixed until homogenized. The temperature throughout the process was 25-32°C. The composition was as follows: polyimide precursor: 9.1% by mass, carboxylic acid (acrylic acid): 9.0% by mass, zinc carboxylate (zinc formate): 8.9% by mass, solvent (N,N-dimethylacetamide): 36.4% by mass. The resulting liquid was a homogeneous, clear, yellowish viscous liquid.

[0042] (Comparative Example 1) Prior to the preparation, 200.0g of 98% zinc acrylate and 800.0g of N-methyl-2-pyrrolidone were placed in a 2L glass beaker using a hot stirrer, heated to 50°C to dissolve, allowed to cool, and then vacuum filtered (using ADVANTEC quantitative filter paper No. 5C) to prepare the adjusted solution. 1000.0g of polyimide precursor was placed in a 5L planetary mixer, and while stirring, the adjusted solution was added. At this point, significant gelation occurred, and the mixture separated from the solvent and solidified. The temperature throughout this process was 25-30°C. A uniform solution was not obtained as the zinc-containing resin composition of the present invention.

[0043] (Comparative Example 2) In the preliminary step, 1000.0g of 99.5% acrylic acid, 200.0g of 98% zinc acrylate, and 800.0g of N-methyl-2-pyrrolidone were placed in a 3L glass beaker using a hot stirrer, heated to 50°C to dissolve, allowed to cool, and then vacuum filtered (using ADVANTEC quantitative filter paper No. 5C) to prepare the solution. 1000.0g of polyimide precursor was placed in a 5L planetary mixer, and while stirring, the prepared solution was added, at which point it whitened and gelled. The temperature throughout the process was between 25 and 34°C. A uniform solution was not obtained as the zinc-containing resin composition of the present invention.

[0044] (Comparative Example 3) 1000.0g of polyimide precursor was placed in a 5L planetary mixer, and while stirring, 200.0g of acrylic acid was added to homogenize it. Then, 400.0g of 43% zinc 2-ethylhexanoate mineral spirit solution (Fujifilm Wako Pure Chemical Industries, Ltd.) was added in small amounts, causing significant gelation, separation from the solvent, and solidification. The temperature throughout this process was 25-35°C. A homogeneous solution was not obtained as the zinc-containing resin composition of the present invention.

[0045] (Comparative Example 4) 1000.0g of polyimide precursor was placed in a 5L planetary mixer and, while stirring, 200.0g of 99.5% acrylic acid was added and mixed until homogenized. Then, 50.0g of 98% zinc acrylate was added in small increments and stirred for 1 hour. After that, 950.0g of N-methyl-2-pyrrolidone was added in small increments as a solvent and mixed until homogenized. The temperature throughout the process was 25-34°C. The composition was as follows: polyimide precursor: 9.1% by mass, carboxylic acid: 9.0% by mass, zinc carboxylate: 2.2% by mass, solvent: 43.2% by mass. The resulting liquid was a homogeneous, clear, yellowish viscous liquid.

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

[0047] [Appearance] The liquid properties after synthesis were observed visually. ○: Homogeneous solution ×: Non-uniform, non-fluid, or solid matter

[0048] (Reference example) A solution was used that was diluted and homogenized by adding 1200.0 g of N-methyl-2-pyrrolidone to 1000.0 g of the 20% polyimide precursor (UBE, U varnish "Yupia A") used in the examples, and then mixing it.

[0049] (Comparative Example 5) The solution used was obtained by adding 113.6 g of 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 20% polyimide precursor (manufactured by UBE, U varnish "Yupia A") used in the examples, and then mixing and homogenizing it.

[0050] Table 2 shows the results of applying the solutions obtained in Examples 1-5, Comparative Examples 4-5, and the Reference Example to copper plates (rolled copper plates HC0366 manufactured by AS ONE Corporation), heat-treating them by baking to create a film, and performing various evaluations.

[0051] The various evaluation items are described below. Note that JIS K5600-5-6 (Adhesion - Cross-cut method) is used to examine the influence of adhesion to either the undercoat or the substrate, and is used as a qualitative indicator of adhesion to the substrate.

[0052] [Adhesion] The test was conducted in accordance with JIS K5600-5-6 (Adhesion - Cross-cut method). evaluation ○: Indicates the best score [0 points]. △: Indicates a moderate level [3 points]. ×: Refers to the lowest score [5 points].

[0053] [Heat-resistant adhesion] The samples were left standing in a constant-temperature dryer at 400°C for 20 minutes, after which the adhesion and the same tests as described above were performed. evaluation ○: Indicates the best score [0 points]. △: Indicates a moderate level [3 points]. ×: Refers to the lowest score [5 points].

[0054] [EDX] This shows the weight ratio of zinc as determined by energy-dispersive X-ray spectroscopy. The weight ratio of zinc represents the weight percentage of zinc in the total elements detected by energy-dispersive X-ray spectroscopy on the surface of the coating.

[0055] [Pencil hardness] The test was conducted 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, homogeneous solutions were obtained in Examples 1-5 and Comparative Example 4. On the other hand, in Comparative Example 1, a homogeneous solution as a zinc-containing composite composition was not obtained because alkylcarboxylic acid (b) with 1-5 carbon atoms was not used. Similarly, in Comparative Example 2, a homogeneous solution as a zinc-containing composite composition was not obtained because the amount of alkylcarboxylic acid (b) with 1-5 carbon atoms was too high. Comparative Example 3 was non-homogeneous and unsatisfactory because zinc 2-ethylhexanoate with 9 carbon atoms was used as zinc alkylcarboxylic acid (c). Comparative Example 4 is an example where the amount of zinc alkylcarboxylic acid (c) with 1-5 carbon atoms is small, but the appearance at the time of mixing is comparable.

[0059] As shown in Table 2, the coatings using Examples 1-5 exhibited excellent adhesion to copper and heat-resistant adhesion. The reference example was a single coating using a polyimide precursor, resulting in poor copper adhesion. Comparative Example 4, as mentioned above, had a low amount of zinc(C) alkylcarboxylate (C1-C5), resulting in moderately poor copper adhesion. Comparative Example 5 used a silane coupling agent formulation from the prior art, but also exhibited poor copper adhesion. Furthermore, the surface hardness of the coatings in Examples 1-5 was significantly improved compared to the reference example.

[0060] Within the scope described in this invention, adhesion to copper substrates and heat-resistant adhesion can be significantly improved, and various effectiveness can be confirmed.

[0061] The present invention provides a zinc-containing composite composition that can significantly improve the adhesion between a copper substrate and a polyimide resin coating. [Industrial applicability]

[0062] The polyimide precursor-zinc-containing composite composition of the present invention significantly improves the adhesion between copper substrates and thermosetting resins such as polyimide resins, which has been a problem in the past. In recent years, the demand for higher functionality has been expected to accelerate in fields such as insulating films, heat-resistant adhesion, and laminates of electronic components, and improved adhesion between metal conductors and insulators will be highly applicable industrially. Further applications as a functional material in other fields are also expected in the future.

[0063] The following embodiments of the invention are added: [1] (a) Polyimide precursor 2-20% by mass, (b) 3-30% by mass of alkylcarboxylic acid having 1-5 carbon atoms, (c) 3 to 30% by mass of zinc alkylcarboxylate having 1 to 5 carbon atoms and (d) Solvent 3-90% by mass A polyimide precursor-zinc-containing composite composition containing the following: [2] The aforementioned alkylcarboxylic acid (b) having 1 to 5 carbon atoms has the chemical formula: R1-COOH (I) (In formula I, R1 represents a linear or branched alkyl group which may have hydrogen or an unsaturated bond having 1 to 4 carbon atoms.) A polyimide precursor-zinc-containing composite composition as described in [1], represented by [1]. [3] The aforementioned zinc alkylcarboxylate (c) having 1 to 5 carbon atoms has the chemical formula: (R2-COO)2Zn (II) (In formula II, R2 represents a linear or branched alkyl group which may have hydrogen or an unsaturated bond having 1 to 4 carbon atoms.) A polyimide precursor-zinc-containing composite composition represented by [1] or [2]. [4] A 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] A polyimide precursor-zinc-containing composite composition according to any one of [1] to [4], 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 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, and is a polyimide precursor-zinc-containing composite composition according to any one of [1] to [5]. [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-liquid composition containing all of the polyimide precursor (a) to the solvent (d). [8] The aforementioned polyimide precursor-zinc-containing composite composition The polyimide precursor (a) and A solution comprising the C1-C5 alkylcarboxylic acid (b), the C1-C5 zinc alkylcarboxylic acid (c), and the solvent (d), A two-component composition comprising the polyimide precursor-zinc-containing composite composition according to any one of [1] to [7].< / ii> < / ii> < / ii>

Claims

1. (a) Polyimide precursor 2 to 20% by mass, (b) 3 to 30% by mass of 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) Solvent 3-90% by mass A polyimide precursor-zinc-containing composite composition containing a zinc precursor.

2. The alkylcarboxylic acid (b) having 1 to 5 carbon atoms has the chemical formula: R １ -COOH (I) (In formula I, R １ (This represents a linear or branched alkyl group that may have hydrogen or an unsaturated bond with 1 to 4 carbon atoms.) A polyimide precursor-zinc-containing composite composition according to claim 1, as represented by the above.

3. The aforementioned zinc alkylcarboxylate (c) having 1 to 5 carbon atoms has the chemical formula: (R ２ -COO) ２ Zn (II) (In formula II, R ２ (This represents a linear or branched alkyl group that may have hydrogen or an unsaturated bond with 1 to 4 carbon atoms.) A polyimide precursor-zinc-containing composite composition according to claim 1 or 2, as represented by the above.

4. The polyimide precursor-zinc-containing composite composition according to claim 2, wherein the alkylcarboxylic 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 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, dimethyl sulfoxide, 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 aforementioned polyimide precursor-zinc-containing composite composition The polyimide precursor (a) and A solution comprising the C1-C5 alkylcarboxylic acid (b), the C1-C5 zinc alkylcarboxylic acid (c), and the solvent (d), The polyimide precursor-zinc-containing composite composition according to claim 1, which is a two-component composition comprising the following components.

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