JPH06312291A - Flux composition and production of flux composition - Google Patents

Abstract

PURPOSE:To provide a flux compsn. which eliminates washing of flux residues and with which the appearance and electric characteristics of wiring boards are excellent by incorporating specific ratios of a specific acivator isocyanate compd. into the flux compsn. CONSTITUTION:This flux compsn. contains 1 to 5wt.% activator consisting of at least >=1 kinds selected from a group consisting of org. acids and amines and 1 to 7wt.% isocyanate compd. as essential components. The org. acids are at least >=1 kinds of the compds. selected from a group consisting of formic acid, oxalic acid, malonic acid, etc., and the amines are >=1 kinds of the compds. selected from a group consisting of diethanol amine, triallyl amine, etc. Since the isocyanate compd. is reactive, the wiring boards are heated to 230 deg.C and the isocyanate compd. and the activator bond to each other when the flux is applied on the wiring boards and the wiring boards come into contact with molten solder. Then, the flux compsn. loses the function as the activator after the soldering and acquires a film forming function, therefore, the need for removing the flux residues is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soldering flux composition and a method for producing the flux composition. More specifically, the present invention relates to a soldering flux composition that does not require cleaning of flux residues after soldering and a method for producing the same.

[0002]

2. Description of the Related Art Flux is roughly classified into inorganic flux, organic flux and resin flux.
Of these, resin-based flux is used in telecommunications equipment and the like, but in equipment requiring high-level electrical characteristics, flux residue is removed by cleaning with chlorofluorocarbon or trichlene.

[0003] However, the Montreal Protocol in 1987 and the like agreed that the abolition of specific CFCs and chlorinated hydrocarbons was made, and the non-cleaning of flux residues and the cleaning with an alternative solvent have become urgent issues.

It is extremely difficult to make the conventional resin-based flux unclean as it is, because the wiring board has poor appearance and poor electrical characteristics. Further, even if the resin content of the conventional resin-based flux is reduced to make it non-cleaning, the soldering characteristic and the electrical characteristic are impaired and it cannot be put to practical use. On the other hand, since the organic flux has a large corrosive effect on the organic acids and amines used as activators, it is essential to clean the flux residue.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve these problems of the prior art. There is no need to wash the flux residue after soldering, and the appearance of the soldered wiring board And to provide a flux composition having excellent electrical characteristics.

[0006]

That is, the present invention relates to 1 to 5% by weight of an activator (A) composed of at least one compound selected from the group consisting of organic acids and amines and an isocyanate compound (B). ) 1 to 7% by weight is contained as an essential component to provide a flux composition.

In the present invention, an activator comprising at least one compound selected from the group consisting of organic acids and amines and an isocyanate compound are dissolved and mixed in an organic solvent at a temperature not higher than the boiling point of the organic solvent. The present invention provides a method for producing a flux composition characterized by the above.

Examples of the organic acid as the component (A) of the present invention include:
Formic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, hydroxybenzoic acid, glycolic acid, lactic acid, malic acid, tartaric acid, pyruvic acid, dimethylolpropionic acid, levulinic acid, Examples thereof include citric acid and itaconic acid. Among these organic acids, malonic acid, adipic acid, pimelic acid, malic acid, citric acid, dimethylolpropionic acid and succinic acid are particularly preferable.

Examples of the amines of the component (B) of the present invention include diethanolamine, triallylamine, isobutylamine, cyclohexylamine, N, N-diethylaniline, di-2-ethylhexylamine, N, N-dimethylethanolamine, Mention may be made of N, N-diethylethanolamine, N-methyl-N, N-diethanolamine, aminoethylethanolamine, N-methylethanolamine, imidazole, 2-alkylimidazole and aminotriazole. Among these amines, diethanolamine, isobutylamine,
N, N-diethylethanolamine, aminoethylethanolamine, imidazole, 2-alkylimidazole and aminotriazole are particularly preferred.

The content of the activator of the component (A) of the present invention in the flux composition is 1 to 5% by weight, preferably 1 to 3% by weight. If the content of the activator is less than 1% by weight,
Poor solderability. If the content of the activator exceeds 5% by weight, the electrical characteristics will be poor.

From the viewpoint of solderability, it is preferable to further mix a halogen salt of an organic acid or a halogen salt of an amine with the flux composition of the present invention. Examples of halogen of the halogen salt include fluorine, chlorine, bromine and iodine. Of these halogens, chlorine and bromine are particularly preferable.

Specific examples of the halogen salt of an organic acid include malonic acid monochloride and adipic acid monochloride. In addition, specific examples of the halogen salt of amines include diethanolamine hydrochloride, 2-methylimidazole hydrochloride and the like. The content of halogen salt of organic acid or halogen salt of amines is preferably 0 to 0.3% by weight,
More preferably, the suitable amount is 0 to 0.15% by weight. If the halogen salt content exceeds 0.3% by weight, the electrical characteristics may deteriorate.

Examples of the isocyanate compound as the component (B) of the present invention include toluene diisocyanate (tolylene diisocyanate), hexamethylene diisocyanate, xylene diisocyanate, isophorone diisocyanate, tolidine diisocyanate, 1,5-naphthalene diisocyanate, and glycols thereof. Examples thereof include addition products of polyols. Of these isocyanate compounds, toluene diisocyanate,
Hexamethylene diisocyanate, xylene diisocyanate, isophorone diisocyanate and their adducts with glycols are particularly preferred.

The content of the isocyanate compound as the component (B) of the present invention is 1 to 7% by weight, preferably 2 to 5% by weight. If the content of the isocyanate compound is less than 1% by weight, the electrical characteristics will be poor. When the content of the isocyanate compound exceeds 7% by weight, the appearance of the wiring board becomes poor.

The molecular weight of the isocyanate compound of the component (B) of the present invention is preferably 2000 or less, more preferably 1
50 to 1000 is suitable. If the molecular weight exceeds 2000, the electrical properties may be poor.

In addition to the above components, the flux composition of the present invention contains organic solvents, foaming agents and the like. If necessary, various rosins such as polymerized rosin, terpene resin and the like are added.

The organic solvent having a boiling point of 70 to 120 ° C. is optimum. If the boiling point is less than 70 ° C, the amount of evaporation per unit time is large and the working environment deteriorates. If the boiling point exceeds 120 ° C., the solvent will not evaporate sufficiently during soldering and the soldering characteristics will be impaired. Examples of such organic solvents include:
Examples include isopropanol, tert-butanol, sec-butanol, isobutanol, n-butanol and the like. The content of the organic solvent in the flux composition is 50
It is preferable to set the content to ˜99% by weight.

The flux composition of the present invention comprises an activator comprising at least one compound selected from the group consisting of organic acids and amines, and a halogen salt of an organic acid or a halogen salt of an amine, which is optionally blended. And an isocyanate compound are dissolved and mixed in an organic solvent at a temperature not higher than the boiling point of the organic solvent.

[0019]

[Function] Conventional rosin and other natural resins used for flux for soldering are all thermoplastic, so the active agent is sealed by cooling and solidifying the resin. 85 ° C, 85% RH)
The flux residue was softened and the action of sealing the activator was lowered, and the electrical characteristics were deteriorated.

On the other hand, in the present invention, since the isocyanate compound is reactive, when the flux is applied to the wiring board and brought into contact with the molten solder, it is heated to 230 ° C. to bond the isocyanate compound and the activator. Therefore, the activator loses its function as an activator after soldering and has a film forming function, so that it is not necessary to remove the flux residue.

[0021]

The present invention will be described in more detail below with reference to examples of the present invention and comparative examples thereof, but the present invention is not limited to these examples.

Comparative Example 1 Polypale resin (polymerized rosin, product name manufactured by Rika Hercules Co., Ltd.) 15 g, malonic acid (manufactured by Wako Pure Chemical Industries, Ltd.) 1 g, succinic acid (manufactured by Wako Pure Chemical Industries, Ltd.) 0.5 g,
A flux composition was obtained by dissolving and mixing 1 g of 2-methylimidazole in 82.5 g of isopropyl alcohol at 30 ° C.

Example 1 4 g of T-80 (tolylene diisocyanate, trade name of Nippon Polyurethane Co., Ltd.), 0.4 g of malonic acid (manufactured by Wako Pure Chemical Industries, Ltd.), succinic acid (manufactured by Wako Pure Chemical Industries, Ltd.)
4 g, 2-methylimidazole (manufactured by Shikoku Kasei Co., Ltd.)
0.4 g was dissolved and mixed in 94.8 g of isopropyl alcohol (manufactured by Tokuyama Soda Co., Ltd.) at 80 ° C. to obtain a flux composition.

Example 2 In Example 1, 1 g of G-125 (terpene resin, trade name of Yasuhara Yushi Co., Ltd.) was used in combination.

Comparative Example 2 In Example 1, T-80 (tolylene diisocyanate, trade name of Nippon Polyurethane Co., Ltd.) was reduced to 0.5 g.

Comparative Example 3 In Example 1, the amount of T-80 (tolylene diisocyanate, trade name of Nippon Polyurethane Co., Ltd.) was increased to 8 g.

Comparative Example 4 Instead of T-80 (tolylene diisocyanate, trade name of Nippon Polyurethane Co., Ltd.) in Example 1, a polyester urethane prepolymer (isocyanate content 3.3) was used.
6%, molecular weight 2500, manufactured by Hitachi Chemical Polymer Co., Ltd.)
Was used.

Comparative Example 5 In Example 1, the amounts of malonic acid (manufactured by Wako Pure Chemical Industries, Ltd.), succinic acid (manufactured by Wako Pure Chemical Industries, Ltd.) and 2-methylimidazole (manufactured by Shikoku Kasei Corporation) were reduced to 0.3 g each. did.

Comparative Example 6 In Example 1, the amounts of malonic acid (manufactured by Wako Pure Chemical Industries, Ltd.), succinic acid (manufactured by Wako Pure Chemical Industries, Ltd.), and 2-methylimidazole (manufactured by Shikoku Kasei Co., Ltd.) were increased to 2 g.

Example 3 2 g of T-80 (tolylene diisocyanate, trade name of Nippon Polyurethane Co., Ltd.), 1.7 g of adipic acid (manufactured by Wako Pure Chemical Industries, Ltd.), polypale resin (polymerized rosin,
Rika Hercules Co., Ltd. product name 1.5 g and isopropyl alcohol (Tokuyama Soda Co., Ltd. product) 94.8 g were dissolved and mixed at 80 ° C. to obtain a flux composition.

Example 4 3.3 g of T-80 (tolylene diisocyanate, trade name, manufactured by Nippon Polyurethane Co., Ltd.), 1.5 g of 2-methylimidazole (manufactured by Shikoku Kasei Co., Ltd.), Polypale resin (polymerized rosin, Rika Hercules) Product name manufactured by Co., Ltd.)
1g, isopropyl alcohol (made by Tokuyama Soda Co., Ltd.)
94.2 g was dissolved and mixed at 80 ° C. to obtain a flux composition.

Example 5 1.3 g of T-80 (tolylene diisocyanate, trade name manufactured by Nippon Polyurethane Co., Ltd.), 1 g of adipic acid (manufactured by Wako Pure Chemical Industries, Ltd.), adipic acid monochloride (prototype according to our conventional method) 0 .1 g, Polypeel resin (polymerized rosin, manufactured by Rika Hercules Co., Ltd.) 3 g, isopropyl alcohol (Tokuyama Soda Co., Ltd.) 94.6
g was dissolved and mixed at 80 ° C. to obtain a flux composition.

Example 6 T-80 (tolylene diisocyanate, trade name of Nippon Polyurethane Co., Ltd.) 2.3 g, 2-methylimidazole (manufactured by Shikoku Kasei Co., Ltd.) 1 g, 2-methylimidazole hydrochloride (normally used by us) (Prototype by the method), 0.1 g of polypale resin (polymerized rosin, product name of Rika Hercules Co., Ltd.), and 94.6 g of isopropyl alcohol (manufactured by Tokuyama Soda Co., Ltd.) are dissolved and mixed at 80 ° C. to obtain a flux composition. It was

The obtained Examples 1, 2, 3, 4, 5, 6,
Two flux compositions of Comparative Examples 1, 2, 3, 4, 5, and 6 were applied to FR-4 type wiring boards, respectively, and 240
When soldering was performed at ℃, the results shown in Table 1 were obtained.

[0035]

[Table 1] * Substrate used: FR-4 (glass substrate epoxy resin substrate) JISII type comb pattern test conditions: 60 ° C, 85% RH, applied voltage DC100
V measurement voltage: DC500V

[0036]

According to the present invention, there is no need to wash the flux residue after soldering, and a flux composition excellent in both appearance and electrical characteristics of a soldered wiring board was obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Watanabe 3-8-40 Kitamiya, Tokushima City, Tokushima Prefecture Hitachi Chemical Polymer Co., Ltd. Tokushima Factory (72) Inventor Kazuhisa Ikuta 3-8 Kitamiya, Tokushima City, Tokushima Prefecture No. 40 Hitachi Chemical Polymer Co., Ltd. Tokushima factory

Claims (9)

[Claims] 1. An activator 1 to 5 comprising at least one compound selected from the group consisting of organic acids and amines.
A flux composition comprising, by weight, an isocyanate compound and an isocyanate compound in an amount of 1 to 7% by weight. 2. An activator 1 to 5 comprising at least one compound selected from the group consisting of organic acids and amines.
1% to 7% by weight of an isocyanate compound and an activator comprising at least one compound selected from the group consisting of halogen salts of organic acids and halogen salts of amines.
A flux composition characterized by containing and as an essential component. 3. The organic acid is formic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, hydroxybenzoic acid, glycolic acid, lactic acid, malic acid, tartaric acid, pyruvic acid, The flux composition according to claim 1 or 2, which is at least one compound selected from the group consisting of dimethylolpropionic acid, levulinic acid, citric acid and itaconic acid. 4. The amines are diethanolamine, triallylamine, isobutylamine, cyclohexylamine, N, N-diethylaniline, di-2-ethylhexylamine, N, N-dimethylethanolamine, N, N.
-Diethylethanolamine, N-methyl-N, N-diethanolamine, aminoethylethanolamine, N
-The flux composition according to claim 1 or 2, which is one or more compounds selected from the group consisting of methylethanolamine, imidazole, 2-alkylimidazole, 2-phenylimidazole and aminotriazole. 5. The flux composition according to claim 2, wherein the halogen salt of an organic acid is the halogen salt of an organic acid according to claim 3. 6. The flux composition according to claim 2, wherein the halogen salt of amines is the halogen salt of amines according to claim 4. 7. The flux composition according to claim 2, wherein the content of the halogen salt of an organic acid or the halogen salt of an amine is less than 0.3% by weight. 8. The molecular weight of the isocyanate compound is 200.
It is 0 or less, The flux composition in any one of Claims 1-7. 9. An activator comprising at least one compound selected from the group consisting of organic acids and amines and an isocyanate compound are dissolved and mixed in an organic solvent at a temperature not higher than the boiling point of the organic solvent. And a method for producing the flux composition.