JP2620498B2 - Flux for soldering - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flux for soldering.

[0002]

2. Description of the Related Art A flux for soldering is conventionally prepared by mixing an activator with rosin and, if desired, a suitable solvent, viscosity modifier, antioxidant and other additives. It is used.

The flux using rosins exhibits relatively satisfactory performance in terms of solderability, but all other properties required as a flux, such as heat resistance, cleaning properties, oxidation resistance, etc. Is not always satisfactory. Therefore, various attempts have been made to improve this. For example, when the heat resistance and the water insulation resistance are improved by using the esterified rosin, the washing property, the wettability and the carrier property are lowered, and the compatibility of the hydrogenated rosin with the activator is lowered.

[0004] In particular, soldering of electronic parts and the like requires precise and quick processing, and the soldering temperature is considerably high for speeding up. As described above, the solder using the rosin-based flux has insufficient heat resistance, and generates white smoke, gas, and foul odor due to the evaporation and thermal decomposition of the flux, thereby causing contamination of the soldered portion. This contamination can cause serious deficiencies, especially for soldering precision parts with complex shapes. Especially in the case of greased solder, the problem of harmful effects due to scattered particles due to rapid expansion of the flux filled inside due to heat is a problem.To solve this problem, cut the groove in the greased solder vertically and fill it with flux What has been used, or a flux coated on the solder surface is used. However, in this case, there are problems such as oxidation resistance to air and adhesion, which is not satisfactory.

[0005]

Means for Solving the Problems While studying flux components to solve the above problems, the present inventor has found that an alkylene oxide adduct of an ester of oxycarboxylic acid is used in place of a conventional rosin. , The above problems,
In particular, it was clarified that a soldering flux excellent in heat resistance, cleaning property, wettability, oxidation resistance and the like of the flux can be obtained. That is, the present invention relates to a flux for soldering containing an alkylene oxide adduct of an ester of oxycarboxylic acid having a molecular weight of 200 or more.

In the present invention, the oxycarboxylic acid having a molecular weight of 200 or more includes, for example, a saturated or unsaturated aliphatic carboxylic acid having 12 or more carbon atoms, for example, ricinoleic acid, oxypalmitic acid, oxystearic acid, oxybehenic acid, linoleic acid. Oxides, linolenic oxides and the like are exemplified.

As the ester of oxycarboxylic acid, the above-mentioned oxycarboxylic acid having a molecular weight of 200 or more can be used as a polyvalent compound such as alkylene glycol such as ethylene glycol and propylene glycol, polyalkylene glycol (preferably di- or tri-), glycerin, sorbitol and pentaerythritol. Esters with alcohols or esters with monohydric alcohols such as octyl alcohol, cetyl alcohol and oleyl alcohol, for example, ricinoleic acid monoglyceride, propylene glycol monohydroxylaurate, pentaerythritol tetra-12-hydroxystearate, castor oil, hydrogenated castor oil, etc. Is exemplified. Castor oil and hardened castor oil are particularly preferred.

[0008] Examples of the alkylene oxide include ethylene oxide and propylene oxide. Particularly, ethylene oxide or those to which both ethylene oxide and propylene oxide are added are preferable. The number of moles of alkylene oxide added is preferably 1 to 6 moles per hydroxy group.

The molecular weight of the ester of oxycarboxylic acid is preferably 200 or more, particularly preferably 400 to 400.
1000. If the molecular weight is smaller than 200, the heat resistance becomes insufficient, and if it is larger than 1,000, the cleaning properties generally decrease. Therefore, lower oxycarboxylic acids such as lactic acid and salicylic acid cannot be used as they are, but must be esterified with higher carboxylic acids and used.

The alkylene oxide adduct of the oxycarboxylic acid ester of the present invention has high water barrier properties and gas barrier properties, and exhibits excellent insulating properties and non-corrosive properties. Further, in the present invention, a primary carboxylic acid is preferable, whereby the action of converting various metal oxides into metal soap is improved as compared with rosins, and as a result, the solderability is improved. Moreover, the detergency does not decrease due to the function of the intrinsic hydroxyl group. In addition, defects such as a decrease in solderability and a decrease in wettability of a metal surface when a large amount of rosin ester is blended, as often observed in a conventional rosin flux as an effect of a hydroxyl group, are eliminated.

The flux for soldering of the present invention contains other components, such as an activator (amine hydrochloride), a solvent (glycols, hydrocarbons, alcohols, ketones and esters), and a viscosity adjusting agent, which are blended in the conventional flux. Agents, antioxidants and the like are appropriately compounded. Moreover, you may use together with rosins. In this case, the amount of the oxycarboxylic acid or its derivative to be added is preferably larger than that of the rosins, but is not limited thereto, and may be added in an appropriate amount based on the intended use of the flux, the required performance, and the like. Good. The flux for soldering of the present invention can be used for grease solder, liquid flux and the like.

Hereinafter, the present invention will be described with reference to examples. Example 1 and Comparative Examples 1 to 4 (Liquid flux) A flux was prepared according to the following formulation. Formulation parts by weight Castor oil Ethylene oxide (13 mol) adduct or 20 Other carboxylic acids Unesterified phenol-modified rosin 19 Diethylamine hydrobromide 1 Isopropanol 60

Table 1 shows the properties of the above flux. For comparison, natural rosin (U
A flux was prepared using S gum WW), polymerized rosin, lactic acid, and oleic acid, and the properties of the obtained flux are also shown in Table 1.

[0014]

[Table 1]

Example 2 and Comparative Example 5 (Flux for solder containing solder) A flux for solder containing fat was prepared according to the following formulation. Formulation parts by weight Castor oil Ethylene oxide (13 mol) adduct 68 Hydrogenated rosin 30 Diethylamine HCl salt 2 Using the flux of the above formula, prepare a greased solder,
Tested as above. For comparison, a flux was prepared and tested using natural rosin (US gum rosin WW) instead of the oxycarboxylic acid ester of the above formulation. Table 2 shows the results.

[0016]

[Table 2]

[0017]

The flux for soldering of the present invention has heat resistance,
Excellent cleaning properties, wettability and oxidation resistance.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hideo Chaki 3-8-10 Mitsuyanaka, Yodogawa-ku, Osaka-shi, Osaka Inside Nihon Genma Co., Ltd.

Claims (3)

(57) [Claims] 1. A soldering flux containing an alkylene oxide adduct of an ester of oxycarboxylic acid having a molecular weight of 200 or more. 2. The flux according to claim 1, wherein the oxycarboxylic acid ester is castor oil or hardened castor oil. 3. The flux according to claim 1, wherein the alkylene oxide adduct of the oxycarboxylic acid ester is an ethylene oxide adduct of castor oil.