JPS61208891A - Rust prevention for metal base printed circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for preventing rust of a metal-based printed circuit board in which the metal plate is rust-proofed in a metal-based printed circuit board using a metal plate as a paste.

[Background technology]

Conventionally, metal-based printed circuit boards in which a layer is laminated on the back side of a metal plate through a pot layer have the disadvantage that rust easily occurs on the metal plate. There was a problem in which rust progressed inward from between the metal plate and the insulating layer, causing the insulating layer to peel off. As a countermeasure, the front and back surfaces of the metal plate of the base are treated with anti-rust treatment, and then integrated with the circuit layer through an insulating layer.During punching and drilling, the circuit layer is layered from the metal plate side of the base. Attempts have been made to process the outside of the metal plate so that the anti-rust treatment covers the cross-section of the metal plate, but the anti-corrosion treatment cannot cover the entire cross-section of the metal plate and rust occurs. could not be eliminated.

[Purpose of the invention]

An object of the present invention is to provide a metal-based printed circuit board that can prevent the occurrence of rust.

[Disclosure of the invention]

The present invention provides a metal-based printed circuit board in which a metal plate and a circuit layer are integrated with an insulating layer interposed therebetween, in which an alkali silicate paint is applied to a cross section of the metal-based printed circuit board,
Since this is a method for preventing rust of a metal-based printed circuit board by baking, it is possible to prevent rust from forming in the cross section.The present invention will be described in detail below.

The metal plate used in the present invention is not particularly limited, and may be made of iron, stainless steel, aluminum, copper, brass, nickel, etc. alone, an alloy, or one having a rust-preventing layer on the front and/or back surface. As the circuit layer, a circuit layer such as a metal foil of copper, brass, aluminum, nickel, etc. is used, and the circuit layer is not particularly limited. The insulating layer may be a resin coating layer, a resin-impregnated base material alone or in combination, and is not particularly limited. Alkali silicate-based paints to be applied to cross-sectional areas generated during punching and drilling processes, cutting processes, etc. include alkali metal silicates such as potassium silicate, alkali tin silicates, aluminum silicates, etc. One or more silicates are used. Application can be done by brushing, spraying, dipping, etc. After applying the alkali silicate paint, it is set at a temperature of room temperature to 120°C, and then heated to a temperature of 150 to 230°C. It is baked at a temperature of about 1 to 1 minutes to harden, and the baking is done by cooling after hardening. The cured film of alkali silicate paint formed by baking is preferably applied to a thickness of 5 microns or more. It is preferable to repeat the steps of applying the acid-based paint, setting, and baking several times so that a cured film of the alkali silicate yarn is formed in multiple layers. In other words, even if bubbles or the like occur in this cured film, by forming multiple layers, the bubbles are closed and corrosion-resistant hardening can be enhanced. Further, since alkali silicate paints originally form a colorless transparent cured film that makes it difficult to distinguish the coated state with the naked eye, it is preferable to use colored alkali silicate paints.

The present invention will be explained below using examples.

Examples 1 to 3 A 0.0351llO steel foil was layered on one side of a steel plate with a thickness of IW and aluminum-plated on the front and back sides with an epoxy resin-impregnated glass cloth of 0.11EI in between, and heated and pressed to integrate. A metal-based printed circuit board is punched and drilled, and alkali silicate paint (A M-500, manufactured by Matsushita Electric Works Co., Ltd.) is applied to the cross section to a thickness of IiJ! They were coated to a thickness of 1 micron for Example 11C, 5 microns for Example 2, and 10 microns for Example 3, and baked at 150° C. for minutes to obtain metal-based printed circuit boards.

Comparative Example A comparative example was one in which the alkali silicate paint was not applied to the cross section.

〔Effect of the invention〕

6 metal-based printed circuit boards of Examples 1 to 3 and comparative example.
% saline solution for 168 hours and then examined the state of rust formation and the adhesion of the insulating layer.As is clear from Table 1, the performance of the metal-based printed circuit board of the present invention was good compared to the metal of the present invention. It has been confirmed that the rust prevention method for base printed circuit boards is excellent.

Chapter 1 Table

Claims (2)

[Claims] (1) A metal-based printed circuit board in which a metal plate and a circuit layer are integrated through an insulating layer, characterized in that an alkali silicate-based paint is applied and baked on the cross-section of the metal-based printed circuit board. Rust prevention method for metal-based printed circuit boards. (2) A method for preventing rust of a metal-based printed circuit board according to claim 1, which comprises using a colored alkali silicate paint.