JPS62168695A - Flux composition - Google Patents

Abstract

PURPOSE:To provide a substantial matting effect and excellent cleaning property to the titled compsn. by compounding a specific ratio of a matting additive with a base flux having a matting effect. CONSTITUTION:The additive having the matting effect on a resist surface as well is added into the base flux having the intermediate material effect on a soldered surface of a printed wiring board, etc., at 5-100pts.wt. per 100pts.wt. resin component of the flux. Pulverized PP powder, HDPE, or montanate wax, etc., are selected for the additive. The substantial matting effect is obtd. over the entire surface of the soldered surface and resist surface by such flux compsn. The excellent effect is also obtd. for the cleaning property.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a flux composition for soldering, which has a matting effect not only on the solder surface of a subsequent printed wiring board but also on the resist surface. This invention relates to an all-over matte flux composition with excellent cleaning properties.

PRIOR ART Conventionally, various fluxes have been put into practical use that have a matting effect on the solder surface of a printed wiring board after soldering, but a flux that also has a matting effect on the resist surface and is easy to clean has not been provided. It has not been. For this reason,
Conventional matting fluxes only have a matting effect on the solder surface, and even if they do have a matting effect on the resist surface, they have poor cleanability, making them difficult to put into practical use.

Flux, which has a matting effect only on the solder surface, has the disadvantage that the operator's eyes are easily fatigued by the gloss of the resist surface, that is, the reflected light, when inspecting the printed wiring board after soldering.

In order to eliminate such drawbacks, there are the inventions of JP-A-51-18245 and JP-A-51-21546, but in the former invention, an inorganic oxide fine powder or an inorganic oxide fine powder or a matting additive is added to the flank space as a matting additive. I am trying to obtain a completely matte flux by adding organic acid metal salt fine powder, but
This invention has the following problems.

(1) The matte effect on the solder surface is determined by whether or not the underlying flank space has a matte effect, so by using a flux space that does not have the matte properties of solder and adding the above-mentioned matte additives. However, the gloss on the solder surface will not disappear.

(2) Silicic anhydride (SiO□
), aluminum oxide, clay, titanium oxide, talc and silica gel, but in reality these have little effect or are limited to certain grades if at all.

(3) Aluminum stearate, oleate, and palmitite are exemplified as organic acid metal salt fine powders, but in reality, these have little effect, and even stearate has no effect at all if the metal is different. .

Next, the latter invention (Japanese Unexamined Patent Publication No. 51-21546) proposes adding polyethylene fine powder to the flux space, but according to the inventor's tests, as will be detailed later, the grade of By appropriately selecting the amount of polyethylene added, it is true that remarkable matte properties can be achieved, but on the other hand, polyethylene has the disadvantage that the cleaning performance worsens as the amount of added polyethylene increases, making it difficult to put it into practical use. is extremely difficult.

Purpose The present invention was made in order to eliminate the drawbacks of the above-mentioned prior art, and its purpose is to add a matting additive for the resist surface to a base flux that has a matting effect on the solder surface. By adding 5 to 100 parts by weight, preferably 10 to 50 parts by weight, per 100 parts by weight of the resin content of the pace flux, it is possible to not only have a sufficient matting effect on the entire solder surface and resist surface, but also improve cleanability. The goal is to obtain an extremely excellent all-over matte flux. Another purpose is to use polypropylene fine powder as the matting additive to obtain an all-over matt flux whose all-over matt properties and washability are significantly superior to those using all other additives. . Another objective is to find a grade and amount of polyethylene with excellent washability when used as a matting additive, and to put it to practical use as a matting additive. Another object of the present invention is to obtain an all-over matting flux composition with excellent matting properties and washability of flux residue by using Montanic acid ester wax, seranox swanx, and white carbon as matting additives. Still another object is to obtain a powder flux composition that is completely matte by including not only liquid flux but also natural rosin, stearic acid, ethylamine hydrobromide, and fine polypropylene powder.

In short, the present invention (specific invention) provides a flux for soldering, in which a base flux having a matting effect on the solder surface is added with a matting additive for the resist I/surface, based on 100 parts by weight of the resin content of the base flux. It is characterized by adding 5 to 100 parts by weight. Further, the present invention (second invention) is characterized in that, in the soldering flux, fine polypropylene powder is added as a matting additive for the resist surface to a base flux having a matting effect on the solder surface. It is something to do. The present invention (third invention) also provides a flux for soldering, in which high-density polyethylene is added to a base flux having a matting effect on the solder surface, and high-density polyethylene is added to 100 parts by weight of the base flux as a matting additive for the resist surface. It is characterized by adding 5 to 100 parts by weight. In addition, the present invention (fourth invention) provides a soldering flux in which a base flux having a matting effect on the solder surface is added as a matting additive for the resist surface selected from montanic acid ester wax, shellac wax, and white carbon. It is characterized in that any one of these is added. Further, the present invention (fifth invention) is characterized in that the soldering flux contains natural rosin, stearic acid, ethylamine hydrobromide, and polypropylene fine powder.

In order to obtain a matte effect on the entire surface of a printed wiring board, that is, to make the flux residue matte, the following properties are required of the additive.

+11 Uniformly melted or dispersed in the base flux.

(2) The particle size must be large enough to be applied uniformly to a printed wiring board.

(3) Soldering must not decompose due to temperature.

(4) Base flux soldering should not have any negative effect on performance.

(5) Soldering must be able to eliminate the gloss left behind by flux.

(6) When the base flux is removed by cleaning, it is easily removed from the substrate together with the flux components.

(7) Excellent electrical insulation and no corrosion.

The inventor of the present application conducted many experimental studies and tests in order to obtain a matting additive that satisfies all of the above requirements.
As a result, in the flux used for soldering, in order to obtain a matting effect on the entire surface, add a matting additive for the resist surface to the base flux that has a matting effect on the solder surface, based on 100 parts by weight of the resin content of the base flux. It has been confirmed that it is best to add 100 parts by weight, preferably 10 to 50 parts by weight. A flux composition to which a matting additive is added in such an amount has not only a matting effect on the solder surface but also a sufficient matting effect on the resist surface, that is, the flux residue. In some cases, the cleaning properties of flux residues are very good. The composition of this base flux is preferably one containing, for example, natural rosin, phenol-modified rosin, amine hydrogen halide salt (activator), organic acid (matting agent), and isopropyl alcohol (solvent).

The amount of the matting additive added varies depending on the type of base flux and additive, the type of printed wiring board, and the surface condition, and it is necessary to determine the amount within the above range as appropriate based on the degree of matting of the flux residue.

Here, the minimum addition amount of the matting additive is 5 parts by weight per 100 parts by weight of the resin content of the base flux.
This is because if the amount is less than 5 parts by weight, the matting effect will be insufficient and it cannot be put to practical use. Also, the maximum amount added is 100
The reason for using parts by weight is that if the amount added is larger than this, not only will the improvement in the matting effect become saturated, but in some cases, the viscosity of the flux will increase too much, and the cleaning properties of Franks residue will decrease. This is because it cannot be put to practical use.

Next, the matting additive will be explained. For use in the present invention, matting additives include natural waxes as shown in Table 1, polymer powders as shown in Table 2,
Inorganic powders as shown in Table 3 and metal soaps as shown in Table 4 were investigated. The test method is to use a commercially available flux (e.g. Base Flux AGF-200XS manufactured by Asahi Chemical Research Institute, resin content 20%) as a pace flux, and dissolve or disperse 5 parts by weight of an additive to make the entire surface matte in 100 parts by weight of this flux. Let's do it, Gion
It was applied to a phenol board, dried, and soldered at 240°C for 5 seconds. After cooling, the matte state of the flux remaining on the board was visually determined. In each table, ◎ indicates an excellent result, ○ indicates a good result, and × indicates a poor result.

That is, in Table 1, for natural waxes, etc.,
It was found that montan acid wax, montan acid ester wax, microcrystalline wax and shellac wax have excellent matting properties. However, although montanic acid ester partially saponified wax is good,
It was determined that stearic acid 12-hydroxystearate, stearyl hydroxystearate, and N,N-ethylenebisoctadecyl acid had poor matting properties, and all natural waxes It is clear that it cannot be used as a matting additive.

Next, in Table 2, as a result of examining additives for polymer powder, it was found that among polyethylenes, only high-density polyethylene had excellent matting properties. That is, only polyethylene with a density of 0.94 to 0.96 has excellent matte properties, but polyethylene with a density of 0.93
If the density is below, it will be less than good, especially if the density is 0.9
It was found that when it was about 2, the matting properties were poor and it could not be put to practical use.

The most important thing is that the polypropylene in the polymer powder shown in Table 2 with a density of 0.93 and an average particle size of 2.5 μm has excellent matting properties, and as will be described later, it also has excellent cleaning properties. It turned out that

As shown in the same table, it was confirmed that the phenol resin spherical fine powder, the benzoguanamine resin spherical fine powder, and the acrylic fukurene resin spherical fine powder had poor matting properties. Therefore, it has become clear that not all polymer powders can be used as matting additives, and in particular, it has been confirmed that even polyethylene with a density of 0.92 or less cannot be used for practical purposes. It was.

Also, to explain the relationship between the amount of polyethylene added and matting properties and washability using Figure 1, as shown by the solid line in the figure, the matting properties become better as the amount of polyethylene added increases, but on the other hand, The detergency of the material deteriorates as the amount of polyethylene added increases. Therefore, when using polyethylene as a matting additive, the amount added should be 2 parts by weight per 100 parts by weight of the resin content of pace flux.
It is best to use about 5 parts by weight, and if the amount is more or less than that, either the matting properties or the cleaning properties will deteriorate, resulting in a practically unfavorable result.

Next, regarding the inorganic powders shown in Table 3, the average particle size is 4.
5μm white carbon has excellent matte properties,
In addition, it was found that calcium carbonate was good, white carbon with an average particle size of 2.0 or 1.0 had poor matting properties, and hydrophobic silica had poor matting properties. Therefore, the only inorganic powders that can be put to practical use are white carbon and calcium carbonate with an average particle size of 4.5 μm.

Next, regarding the metal soaps shown in Table 4, aluminum stearate was judged to have good matting properties, and other metal soaps such as calcium stearate, magnesium stearate,
It was found that barium stearate and zinc stearate had poor matting properties and could not be put to practical use.

Effects Since the present invention is constructed as described above, the base flux having a matting effect on the solder surface is added with a matting additive for the resist surface at a rate of 5 parts per 100 parts by weight of the resin content of the pace flux. By adding 100 to 100 parts by weight, preferably 10 to 50 parts by weight, it is possible to obtain a full-surface matting flux that not only has a sufficient matting effect on the entire solder surface and resist surface, but also has extremely excellent cleanability depending on the additive. It has the effect of In addition, since fine polypropylene powder is used as the matting additive, it is possible to obtain an all-over matting flux that has far better all-over matting properties and washability than those using any other additives, making it truly practical. As a result, it is possible to obtain a matte flux on the entire surface of the printed wiring board, and as a result, the soldering of the printed wiring board has the effect of sufficiently preventing eye fatigue of the operator due to reflected light during subsequent inspection and repair work. Furthermore, when polyethylene is used as a matting additive, a grade and amount to be added with excellent washability have been determined, and it has become possible to put the polyethylene to practical use as a matting additive. Also, as a matting additive,
Since montanic acid ester wax, shellac wax and white carbon are used, it is possible to obtain an all-over matte flux composition with excellent mattness and washability of flux residue. Furthermore, it is not limited to liquid flux,
Since it contains natural rosin, stearic acid, ethylamine hydrobromide, and polypropylene fine powder, it has the effect of making it possible to obtain a flux composition with a completely matte powder surface, and as a result, organic solvents such as isopropyl alcohol can be used. This method has the effect of making it possible to obtain a flux that is safe in all respects without the use of

Example 1 When a commercially available flux as shown in the table is used as the pace flux, and when an additive made of high-density polyethylene with an average particle size of 2.5 μm is used, the amount of When the proportion of the additive was 5 parts by weight (25 parts by weight for the resin content of 1.00 parts by weight), there was no gloss of flux residue and the cleaning properties were good. It has therefore been found that polyethylene can be used as an all-over matting additive in such combinations.

Furthermore, when polypropylene fine powder is used for a similar commercially available flux, the gloss of the flux residue is good when the amount added is 1 part by weight, and when the amount added is 2.5 parts by weight and 5 parts by weight. The cleaning performance was excellent in all cases, and the flux residue rate (residue rate) was 0%. Furthermore, when similar polypropylene powder was added to the commercially available flux shown at the bottom of the table, the gloss of the flux residue was good when the addition amount was 2.5 parts by weight, and when the addition amount was 2.5 parts by weight, the gloss of the flux residue was good, and when the addition amount was 2.5 parts by weight, the gloss of the flux residue was good, The cleaning properties were excellent in all cases. The results show that adding polypropylene fine powder to a commercially available flux as an additive for all-over matting is the best in terms of both matting properties and cleanability.

Example 2 In this example, the solder wettability was also evaluated using a meniscograph, and the results showed that it was 0.24 seconds to 0.26 seconds for each additive, which was a large difference from case A with no additives. It was found that among the additives, Montanic acid ester wax, Cera Noqua Nox, high-density polyethylene, white carbon, and polypropylene gave better or better results in both matting properties and cleaning properties.

This shows the composition of a powder-based flux that makes the whole surface matte.The one made by adding the ingredients shown in the table to 100 parts by weight of natural rosin has excellent matt properties on the solder surface and matte property on the resist surface. In Comparative Example 1, ■ in the table,
Those that do not contain ■ have poor matte properties, Comparative Example 2
indicates that it does not contain ■ in the table, and only the matte properties of the solder surface are excellent and the matte properties of the resist surface are poor.In this way, if it does not contain ■ or both ■ and ■, it cannot be used for practical use. It shows that you can't get it.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the relationship between the amount of polyethylene added and matteness and washability.

Claims (1)

[Scope of Claims] 1. In the soldering flux, 5 to 100 parts by weight of a matting additive for the resist surface is added to the base flux that has a matting effect on the solder surface, based on 100 parts by weight of the resin content of the base flux. A flux composition characterized by: 2. The flux composition according to claim 1, wherein the base flux contains natural rosin, phenol-modified rosin, amine hydrogen halide, organic acid, and isopropyl alcohol. 3. A flux composition for soldering, characterized in that it is made by adding polypropylene fine powder as a matting additive for the resist surface to a base flux that has a matting effect on the solder surface. 4 The polypropylene fine powder has a density of approximately 0.93,
The flux composition according to claim 3, wherein the flux composition has an average particle size of approximately 2.5 μm. 5. In soldering flux, 5 to 100 parts by weight of high-density polyethylene is added to the base flux that has a matting effect on the solder surface as a matting additive for the resist surface based on 100 parts by weight of the resin content of the base flux. A flux composition characterized by: 6. The flux composition according to claim 5, wherein the high density polyethylene has a density of 0.94 or more. 7. In the soldering flux, one selected from montanic acid ester wax, shellac wax, and white carbon is added as a matting additive for the resist surface to the base flux that has a matting effect on the solder surface. A flux composition characterized by: 8. A powder flux composition for soldering, characterized by containing natural rosin, stearic acid, ethylamine hydrobromide, and fine polypropylene powder.