JPS6160266A - Soldering method having good freon cleaning property - Google Patents

Abstract

PURPOSE:To make possible cleaning by a solvent containing principally freon of a printed substrate safely after soldering by using rosin amine adding halogen acid as a flex. CONSTITUTION:At the soldering of a printed substrate, a flux for soldering which is principally rosin amine, and compounded amine halogen acid, halogen acid and stearate acid, palmitin acid, azipin acid and compounds of metallic salt therein are used. As the printed substrate after soldering is easily cleaned by solvent containing principally freon, soldering having high electrical insuration can be carried out.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a soldering flux used for soldering printed circuit boards, more specifically a post slack used for soldering parts of printed circuit boards. It is related to.

(Prior art) The most common post flux is one in which rosin is the main ingredient and an activator such as amine halogen acids, halogen acids, stearic acid, palmitic acid, or metal salts of these organic acids are dissolved in isopropyl alcohol. It is used.

(Problems to be Solved by the Invention) After the printed circuit board is soldered, the flux is cleaned with an organic solvent such as trichloroethane, methylene dichloride, alcohol, and Freon to improve the reliability of electronic components. The process is widely adopted. Among these organic solvents, Freon-based solvents, which pose no fire hazard and have very low toxicity, are preferred; however, when using the conventionally used rosin-based flux, Freon-based cleaning agents cannot The disadvantages are that it takes a long time and that the flux residue cannot be completely cleaned and leaves a white residue, so there is a strong desire to develop a flux that can be easily and reliably cleaned with a Freon-based solvent. .

However, a flux in which rosin amine hydrohalide is added to rosin or its derivatives is known, as disclosed in JP-A-57-165198.

However, the scope of the patent claims is a soldering flux characterized by adding rosin amine hydrohalide to rosin or a derivative thereof, and even in the detailed description, the embodiments include rosin. Approximately 10%
From the following description of the rosin amine halide salt, this technical idea is mainly based on rosin or its derivatives, to which a portion of the rosin amine hydrohalide salt is added. Or, the Freon cleaning properties of its derivatives are not sufficient, and when recovering Freon, these rosins and the like stick to the distillation vessel wall of the recovery vessel, making it difficult to clean and causing problems in workability. Ta.

The present invention solves the problems of the conventional soldering flux as described above, and provides a soldering flux that can be easily and reliably cleaned with a Freon-based solvent and has high reliability in the electrical insulation of the board after cleaning. It attempts to provide flux.

(Another Means to Solve the Problem) In order to achieve this object, the present invention does not use the conventional flux mainly composed of rosin or its derivatives, but uses a flux mainly composed of rosin amine, and uses the activating agent conventionally used for this flux. For example, aminino-decogenic acids, halogen acids, stearic acid, palmitic acid, adipic acid, and their metal salts, and 2,3-dibromosuccinic acid having an unstable substituent are combined to make a soldering flux and solder. After soldering, the printed circuit board can be easily and reliably cleaned using a Freon-based solvent, making it possible to perform soldering with extremely high electrical insulation.

Although it is not necessary for the flux of the present invention to contain rosin or its derivatives in its components, even if a small amount of rosin or its derivatives is blended, the flux has good cleaning properties with a Freon-based solvent.

Furthermore, when regenerating Freon from the cleaning solution, the rosin-free flux sticks to the walls of the distiller, making it difficult to remove it, but the present invention's flux residue is easy to handle in liquid form, and is extremely workable in this respect. Become.

(Function) The activator used in the flux of the present invention is mainly made by adding halogen acid to rosin amine, and has extremely high solubility in Freon, so it has excellent Freon cleaning properties after soldering. is very good. Rosin amine is used after being diluted with an organic solvent such as isopropyl alcohol, and solderability is further improved by adding amine norogenic acid, organic acid, rosin, etc.

Even a small amount of the above-mentioned rosinamine norogenate salt exhibits sufficient effects. Furthermore, as mentioned above, the solderability is improved by adding an appropriate amount of a conventionally used activator to the flux of the present invention. You can add it with .

When soldering is performed using the flux of the present invention, conventional flux application methods such as foam tube fluxer, dipping, spraying, and brushing can be applied.

(Example) Next, specific examples of the present invention will be described below.

Soldering was performed in a eutectic solder bath at 245°C, and the dip time was 5 seconds. Printed circuit board is JIS-23
A comb-shaped electrode specified in 197 was used instead, and cleaning after soldering was performed with Daiflon 5-3E (Freon-based cleaning agent manufactured by Daikin Industries). The pH of the flux was adjusted to about 4-5 with halogen acid or the corresponding amine.

Example 1 2 parts of OZamine, 1 part of 80% hydrazine hydrate, and 4003 parts of polyethylene glycol were adjusted to pH 4.5 with 47% HBr, and the remainder was mixed with isopropyl alcohol (
(hereinafter abbreviated as IPA) to 100 parts was used as a flux.

Example 2 5 parts of Zinamine HCl, 0.5 parts of monoethylamine
1 part, 0.5 part of 2.3 dibromosuccinic acid was adjusted to pH 4.0 with 35% HCl, and the remainder was made up to 100 parts with IPA to prepare a flux.

Example 3 0 Zinamine HBr 4.3 parts, 47% HBr 0
．． 3 parts of rosin, 0.2 parts of rosin, and 2 parts of stearic acid were adjusted to pH 5.0 with diethylamine, and the remainder was made up to 100 parts with IPA to prepare a flux.

Example 4 0.0 amine 6 parts, diethylamine 0.3 part.

Add 1 part of zinc stearate to 35% HCl and adjust the pH to 4.
3 and the remainder was made into 100 parts with IPA and used as a flux.

Comparative Example 1 18 parts of gin, 0.5 parts of diethylamine, and 2 parts of stearic acid were adjusted to have a pH of 4.5 with 47% HBr, and the remainder was made up to 100 parts with IPA, and this was used as a flux.

Comparative Example 2 18 parts of rosin, 0.5 parts of diethylamine, 2 parts of stearic acid, 6 parts of rosinamine HBr to 47% HBr
The PH was adjusted to 4.5 using the same method, and the balance was made up to 100 parts with IPA, which was used as a flux.

(Effects of the Invention) Examples 1 to 40 By using the 7 lacs of the present invention, the soldered printed circuit board can be soldered well without any icicles, solder balls, or bridges, and the DIFLON 5 after soldering can be done well. -3E (Freon-based solvent manufactured by Daikin Industries) (Freon 96, ethanol 4) was extremely easy to clean, and each exhibited extremely high electrical insulation resistance values of I x 1014Ω or more. On the other hand, in Comparative Examples 1 and 2, although the solderability was good, white color remained after Freon cleaning after soldering, and the electrical insulation resistance value after Freon cleaning was 1 x 1012j. It was about 1, which was lower than when soldering was performed using the flux of the present invention.

Furthermore, when recovering freon, the flux of the present invention did not cause 7 lux to stick to the wall of the distiller, making it easier to work, but the conventionally used rosin-based flux in the comparative example did not cause flux to stick to the wall of the distiller. It was caked with dirt and it took a lot of effort to clean it.

Patent applicant: Chemicoat Co., Ltd. 1 other person Procedural amendment (release) February 12, 1985

Claims (1)

[Claims] A soldering method with good Freon cleanability, characterized by using rosin amine halide as a soldering flux.