JPH0153982B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an epoxy resin ink composition. This product has excellent electrical insulation, moisture resistance, heat resistance, chemical resistance, and adhesion, and also has the ability to prevent silver or copper discoloration and migration.
Furthermore, since it has quick curing properties at medium to high temperatures, it can be used for manufacturing printed circuit boards and the like. (Prior Art) Conventional printed circuit boards are mainly manufactured by the following method. That is, (A) a desired circuit is formed by screen printing using silver, platinum, palladium conductors, resistors, capacitors, etc. using glass frit as a binder on an inorganic insulating substrate made of a silver-free material such as ceramic or glass as a base material. , a method for manufacturing a so-called thick film integrated circuit board by firing at high temperature. (B) Phenol resin, phenol-modified xylene resin, epoxy resin, etc. are used as binders on a laminated insulating substrate based on organic materials such as paper/phenol, paper/epoxy, glass-epoxy, etc., and silver-based conductors and resistors are used as binders. A method of manufacturing printed circuit boards in which a desired circuit is formed by screen printing and then baked at medium to high temperatures. (C) A method for manufacturing a printed circuit board in which a desired circuit is formed by etching the copper foil of a copper-clad laminate in which copper foil is bonded to a laminate based on the organic material described in (B) above. It is. Incidentally, the surfaces of conductor circuits formed by these methods are usually exposed in a plane and are therefore easily affected by the environmental atmosphere. That is, accidents are likely to occur due to corrosion of the conductor circuit portion due to adhesion of conductor-corrosive impurities or moisture contained in the atmosphere to the conductor. In order to prevent accidents caused by such factors and further improve the reliability of circuits, a method is generally used and practiced in which a protective coating called a permanent resist is formed on the circuit by screen printing or the like. (Problem to be solved by the invention) The protective coating of the printed wiring circuit has electrical insulation,
Various performances such as moisture resistance, chemical resistance, adhesion, and hardness are required. Furthermore, in the thick-film hybrid integrated circuit boards and printed circuit boards, the formed circuits are often minute and complex, so when plating with nickel, gold, copper, solder, etc., short circuits due to the plating may occur. There is a risk of causing To prevent this, a protective coating called resist ink is applied by screen printing to areas where plating is unnecessary.
The method used today is to cure the coating to form a coating and then apply plating only to the necessary areas. is required to function as an ink. Discoloration and migration of silver and copper conductor circuits caused by printing voltages under high temperature and high humidity environmental conditions are a problem that is caused by the recent advances in electronic equipment, such as smaller size, lighter weight, higher density, and higher reliability. This has become a problem today with more sophisticated requirements. With the exception of triazine resin or bis-maleimide-triazine resin, there are almost no protective coating materials that have the ability to prevent discoloration and migration of silver and copper conductors. Traditionally, protective coatings with the above-mentioned properties and functions include baking-type glass-based, heat-curable epoxy resin, phenolic resin-based, melamine resin-based, epoxy-melamine resin-based, silicone resin-based, and ultraviolet curable resin. Paints based on these types are known, but with the exception of glass-based paints, all of them are insufficient in preventing discoloration and migration of silver and copper conductors. Even with the above-mentioned triazine resin system and bis-maleimide-triazine resin system, there are problems in handling such as curing conditions (temperature, time) and pot life, and it cannot be said that they are in a satisfactory state. In view of these circumstances, the inventors of the present invention have conducted extensive research to find a coating that has a long pot life, prevents discoloration and migration of silver and copper conductors, and has various properties that are satisfactory as a protective coating. We have now discovered a two-component epoxy resin ink composition that has these functions. (Means for Solving the Problems) That is, the epoxy resin ink composition of the present invention contains at least an epoxy resin, polyvinyl-para-phenol, 2-vinyl-4,6-diamino-
It is a blend of s-triazine and imidazole compounds. When the composition of the present invention is heated, 2-vinyl-4,
The vinyl group of 6-diamino-s-triazine is cleaved and undergoes a polymerization reaction, and the two amino groups attached to the triazine ring also react with the epoxy resin due to the presence of the imidazole compound. Further, the hydroxyl group of polyvinyl-para-phenol also easily reacts with the epoxy resin due to the action of the imidazole compound. Furthermore, the epoxy resin itself is the above-mentioned 2-vinyl-
Apart from 4,6-diamino-s-triazine and polyvinyl-para-phenol, it also reacts with imidazole compounds and is cured by anionic polymerization. As a result of these reactions occurring almost simultaneously,
A coating film is produced that exhibits the various properties necessary for circuit board inks, such as heat resistance, chemical resistance, color fastness, and anti-migration function. However, the pot life of this composition is unfortunately short, so in order to make it practical, it must be used in the following configuration. That is, an epoxy resin, 2-vinyl-4,6-diamino-s-triazine, a filler, etc. are uniformly mixed to form a main agent (hereinafter referred to as liquid A), and then polyvinyl-para-phenol and an imidazole compound, etc. are mixed uniformly. B
Liquid A and a curing agent (referred to as B liquid) are mixed immediately before use. Although the composition according to the present invention has the drawback that it has a short pot life and cannot be stored for a long period of time, making it impractical, this drawback can be overcome by handling it as a two-part composition as described above. . The epoxy resin ink composition of the present invention comprises 5 to 20 parts by weight of 2-vinyl-4,6-diamino-s-triazine, 10 to 40 parts by weight of polyvinyl para-phenol, and 0.025 parts by weight of an imidazole compound, based on 100 parts by weight of epoxy resin. It should be blended in a proportion of 10 to 10 parts by weight. The performance of the protective coating after curing is extremely high, and the curing speed is comparable to that of ultraviolet curing resin paints (which have been frequently used in the field in recent years due to their fast curing speed). The composition according to the present invention can also be used as a protective coating for thick-film hybrid integrated circuit boards, printed circuit boards, etc., and as an insulating layer for multiple (multilayer) wiring. Epoxy resins suitable for the practice of the present invention include polyglycidyl ethers of polyhydric phenols such as bisphenol-A-diglycidyl ether, bisphenol-F-diglycidyl ether, epoxidized phenol-novolac resins, epoxidized cresol-novolac resins, etc. be. In the present invention, the filler can be added in an amount of up to 100 parts by weight to 100 parts by weight of the epoxy resin, and representative examples include barium sulfate,
These include calcium carbonate, talc, mica, silica, aluminum hydroxide, alumina, etc., and these can be used alone or in combination of two or more. Of course, fillers other than these can also be used.

[Formula] 2-vinyl-4,6-diamino-s-triazine represented by the structural formula on the left is
A method of reacting biguanide with acrylic acid chloride [J.Am.Chem, Soc., 80, 988 (1958)], a method of reacting dicyandiamide with β-dimethylamino-propionitrile (French patent no.
1563255) and 1,2-di{4',6'-diamino-s-triazinyl-(2)'}-cyclobutane by heating under reduced pressure (Japanese Patent Publication No. 46-35068). I can do it. The amount used is per 100 parts by weight of epoxy resin.
5 to 20 parts by weight, particularly preferably 7 to 15 parts by weight
Parts by weight. 2-vinyl-4,6-diamino-
If the amount of s-triazine used is outside the above-mentioned range and is too small, there will be no effect of preventing discoloration and migration of silver or copper, the curing rate will be low, and practicality will be lost. Also, if there is too much, the coating film after curing will become brittle.
Lacks functionality as a protective coating.

[Formula] Addition of polyvinyl-para-phenol represented by the structural formula shown on the left significantly improves the adhesion between the coating film and the substrate, and also prevents oozing of a thin patterned coating film during curing. The average degree of polymerization is preferably in the range of 25 to 70. Typical imidazole compounds used in the present invention include 2-methyl-imidazole,
2-ethyl-4-methyl-imidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecyl imidazole, 2-phenyl-4-methylimidazole, 1-position cyanoethyl compounds of these 2-substituted imidazoles, these Carboxylate salt of imidazole compound, 2,4-diamino-6-{2-methylimidazolyl-(1)}-ethyl-s-triazine, 2,4-diamino-6-
{2-ethyl-4-methylimidazolyl-(1)}-ethyl-s-triazine, 2,4-diamino-6-
{2-methylimidazolyl-(1)}-ethyl-s-triazine-isocyanurate, 2-phenyl-
4,5-dihydroxymethylimidazole, 2-
Examples include phenyl-4-methyl-s-hydroxymethylimidazole, and a fast-curing composition can be obtained by using one or a combination of two or more imidazole compounds that are highly reactive with epoxy resins. Imidazole compounds, such as 2-methylimidazole, 2-ethyl-4-methylimidazole, etc., which are soluble in polyvinyl-para-phenol solvents such as butyl carbitol-acetate, etc., are used dissolved in the solvent, and imidazole compounds that are insoluble in the solvent are used. The imidazole compound is dispersed in a polyvinyl-para-phenol solution using a kneader such as a three-roll mill so that the particle size is 10 microns or less. The curing temperature of the composition in the present invention is between 130 and 130°C.
It is in the range of 200℃. (Example) Each composition in the Examples and Comparative Examples was uniformly dispersed and kneaded using a three-roll mill so that the particle size was 10 microns or less. Performance tests were conducted on the compositions prepared according to Table 1, and the results are shown in Tables 2 and 3.

[Table] The mixing ratio of liquid A and liquid B should be determined depending on the performance, but in this example, the weight ratio of liquid A: liquid B was 100:13.6. Comparative examples 1 to 3
is a one-component epoxy resin ink composition. The commercially available product of Comparative Example 4 is an ultraviolet curing solder resist UR3000 manufactured by Sanwa Chemical Industries, Ltd.

【table】

[Table] However, a coating film with a thickness of 20 μm was formed by screen printing, and this was cured at 150°C for 15 minutes. * Commercially available resist: An ultraviolet curable ink composition. The curing conditions were irradiation with three 80W/cm ozone-free high-pressure mercury lamps and a furnace speed of 4m/min. (Note) (3) The test piece was placed at a temperature of 60℃, humidity of 95%, and an applied voltage.
Measurements were taken at predetermined time intervals under the condition of DC30V. (4) Etching the copper foil of the NEMA standard XPC copper-clad laminate with a conductor line width of 0.5 mm and conductor spacing of 0.3 nm.
A test piece obtained by forming a comb-shaped electrode circuit, screen-printing the formulation of each example on the circuit, and curing it was left under the above conditions for 500 hours. (5) Screen-print silver powder-phenol resin paste on a NEMA standard The formulation of each example was screen printed on the circuit, and the test piece obtained by heat curing was subjected to the conditions of (3) above.
When left for 100 hours. (6) Screen-print a comb-shaped electrode circuit with a conductor line width of 0.5 mm using silver/palladium powder-glass paste on a ceramic substrate, bake it at a temperature of 700°C for 2 hours, and then print each example formulation on the circuit. When a test piece obtained by screen printing an object and heat curing it was left for 500 hours under the conditions described in (3) above. (7) In accordance with JIS-C-2103, each formulation was screen printed on an aluminum plate to form a protective film, and measurements were taken. (8) After immersing the test piece prepared by the method in (4) above in a molten solder bath at 260°C for 30 seconds, observe the appearance of the paint film for blistering, peeling, etc., and cross-wash it according to JIS-D-0202. This is a cut peeling test. (9) Changes in the coating film were observed after the test pieces prepared by the method (4) above were immersed in a 10% sulfuric acid solution and a 10% caustic soda solution for 120 hours. (10) JIS-D-
Pencil hardness was measured according to 0202.

Claims (1)

[Claims] 1. At least epoxy resin, polyvinyl-para-phenol, 2-vinyl-4,6-diamino-
An epoxy resin ink composition containing s-triazine and an imidazole compound. 2 5 to 20 2-vinyl-4,6-diamino-s-triazine per 100 parts by weight of epoxy resin
Parts by weight, polyvinyl-para-phenol 10 to
40 parts by weight and 0.025 to 10 imidazole compounds
The epoxy resin ink composition according to claim 1, wherein parts by weight of the epoxy resin ink composition are blended. 3 at least an epoxy resin and 2-vinyl-4,
An epoxy resin ink composition comprising a base agent containing 6-diamino-s-triazine and a curing agent in which at least polyvinyl-para-phenol and an imidazole compound are dissolved in an organic solvent.