SU1454619A1 - Soldering composition - Google Patents

Abstract

The invention relates to soldering, in particular, compositions for protecting metallized holes and conductors of printed circuit boards from molten solder during the process of mechanized soldering of products. The purpose of the invention is to increase the quality of protection and reduce the complexity of the soldering process. The composition contains the following components, wt.%: Natural rubber latex 78.1- 91.59; distilled water 4.57-7.81; castor or industrial oil 1.74-4.95, dibutyl phthalate 0.87-3.37; 2,2-methylene bis-4-methyl-6-tert-butylphenol or phenyl-o-naphthyl-amine 1,402-2,4; 25% aqueous ammonia solution 0.48-2.17; polyvinyl alcohol 0.25-0.87; glycerol or ethylene glycol 0.063-0.304; (naphthaleneulfoxyacid) 0.01-0.026. The composition contains rhodamine C. The composition allows to reduce the time of formation and removal of the protective film by introducing natural rubber into the composition for soldering as a film-forming latex, and dibutyl phthalate as a hardener. This, in combination with the selected quantitative ratio, of the components leads to a 2-2.5-fold decrease in the labor intensity of the assembly and assembly work, while at the same time improving the quality of protection of the metallized holes and conductors of printed circuit boards. 2 hp f-ly, I tab. 5 cl

Description

The invention relates to soldering, in particular to compositions for protecting metallized holes and conductors of printed circuit boards from molten solder during the process of mechanized soldering, and can be used in electrical, instrument-making and electronic manufacturing.

The purpose of the invention is to improve the quality of protection and reduce labor intensity. tO soldering process.

The composition contains components in the following ratio, wt.%:

Natural Rubber Latex Distilled Water

Castor or industrial oil

Dibutyl phthalate, 2,2-Methylene-bis-4-metsh-6-tert-butylphenol or phenyl-o-naphthyl-amine

1,402-2,400

3145

25% water

ammonia solution 0.48-2.17

Polyvinyl

alcohol0.25-0.87

Glycerol or ethylene glycol, 063-0., 304

p-naphthalenesulfonic acid, 001-0,026

In addition, in order to increase the visual assessment of the removal of the composition, it contains rhodamine C or a water-soluble printing dye in the amount of 1-3 wt.%.

The introduction of natural rubber latex creates conditions for film formation when the composition is applied to metal parts of a printed circuit board. At the same time, latex in combination with polyvinyl alcohol forms a film with low adhesion to conductors and mounting holes of printed circuit boards, since the quantitative content of natural rubber latex and polyvinyl alcohol combined with distilled water and glycerin or ethylene glycol provides for thickening of natural latex rubber with the required properties determining the technological effectiveness of the composition, and in combination with castor or industrial oil it allows reducing the adhesion of the formed ple ki to the surface of the mounting holes and a conductor circuit boards nick and, consequently, reduces the forming time, and 2; 2-2.5 times the time for removal of the protective film by mechanical means. This eliminates the need to use any solvents.

All this leads to a significant reduction in the complexity of the soldering process, while at the same time improving the quality of protection, since the applied film adheres well to the surface of the conductors and the metallized holes.

In addition, polyvinyl alcohol is a stabilizer with respect to typographic pigments, which are incorporated into the formulation for tinting in order to enhance the color difference between printed circuit boards on the board and the composition.

Distilled water in a mixture with ethylene glycol or glycerin is not only a solvent of poly (4).

nilovogo alcohol (a well-known property of J, but also its classifier.

The introduction of polyhydric alcohols, to which glycerol and ethylene glycol belong, and their chosen proportion prevents the polyvinyl alcohol from drying out.

Polyvinyl alcohol, taken in certain ratios with distilled water and glycerin or ethylene glycol, is a soldering composition dispersant, which determines its hiding power.

In the production of dispersions, which include natural rubber latexes, a surfactant is used as stabilizers for wetting and dispersing the components. In connection with the general increase in the amount of foam when using non-ionic surfactants, it is advisable to use low-foaming non-nutrient wetting substances such as the product concentration of vegetable oils with 10-20 mol of ethylene oxide. Such surfactant is castor oil. Industrial oil has adequate castor oil properties. Low-wetting wetting agents such as castor or industrial oils help to reduce the number of oily spots. on the surface of the protected areas of printed circuit boards, i.e. provide the proposed composition of hiding power, which contributes to improving the quality of protection of the metallized holes and conductors of printed circuit boards from molten solder.

Dibutyl phthalate is introduced into the composition as a plasticizer of natural rubber latex, i.e. to thicken it. In this case, if dibutyl phthalate in the composition contains less than 0.87% by weight, no protective film is formed. If dibutyl phthalate is present in an amount greater than 3.37%, a thick film is formed that does not have the required rheological properties.

An antioxidant of the phenolic series 2,2-methylene bis-4-methyl-6-tert-butyl-phenol or phenyl-o-naphthylamine in the amount of 1.402-2.4% was introduced into the composition as an inhibitor of oxidative reactions. Its presence is less than I, 402% causes a gradual oxidation of the film-forming, which leads to destruction514546

Research Institute of coating (film drying and cracking). An increase in the amount of the indicated oxidizing agent over 2.4% does not inform the composition of the additional conspicuous properties and, in addition, reduces the efficiency of washing residues after soldering.

The component of the ultraviolet acid line is introduced for the hydrophobization of polyvinyl alcohol, which, at a soldering temperature (in the range of 220–300 ° C) in an amount of 0.001–0.026%, provides for the hydrophobization of polyvinyl alcohol in 30 seconds to avoid corrosion the process of long-term storage of processed printed circuit boards, due to the technological conditions of the enterprise. An increase in the content of | V-naphthalene-sulphoxide-20 lots also reduces the efficiency of the residue casting after soldering.

25% aqueous ammonia solution is included in the composition of the buffer additive,

25

196

adjusting its pH, as stability under alkaline conditions allows the pH of the composition to be increased to minimize corrosion of the conductors of printed circuit boards.

A decrease or increase in the ammonia content beyond the optimum ratio (0.48-2.17 wt.) Leads to corrosion.

The content of natural rubber in the composition of the latex is less than 78.10 wt.%. The integrity of the coating is not ensured, which reduces the quality of protection and at the same time increases the film removal time. When the content of natural rubber latex is greater than 91.59% by weight, the elasticity of the film decreases.

The table shows examples of the soldering composition, primarily to protect the metallized holes and conductors of printed circuit boards from molten solder.

Components

Content, wt.%, In the compositions 1I 2 I 3 I 4I 5I 6

Latex-qual-tex

Latex Revol-Tex

Latex SKI-3

Distilled water

Industrial oil

Castor oil

Dibutylphthalmate

2,2-Methylene-bis-4-metsh-1-6-tertbutylphenol

Fe nil-o (-naphtylamine

78.1 78.1

4.95

2.4

84.85

84.85

3.35

4.95 3.35

2.4 1.402

1,402

91.59. 91, 59

7.81 7.81 6.19 6.19 4.57 4.57

1.74

0.436

1.74

3.37 3.37 2.12 2.12 0.87 0.87

0.436

84.85

84.85

91.59. 91, 59

3.35

1.74

4.95 3.35

1.74

2.4 1.402

0.436

1,402

0.436

25% aqueous ammonia solution

Polyvinyl alcohol

Glycerol

Ethylene glycol

p-naphthalene- with ulfo to use about

2.17 2.17

1, 33

1.33 0.48 0.48

0.87 0.87 a, 56 0.56 0.25 0.25 0.184 - 0.063

0,304 0,304

1, 84

0.026 0.026 0.014 0.014 0.001

0.063

0.001

Compounds 1-6 for soldering, primarily for protecting the metallized holes and conductors of printed circuit boards from molten solder, were prepared as follows. Polyvinyl alcohol was dissolved in a mixture of distilled water and polyhydric alcohol (glycerin, ethylene glycol) in a water bath at (one part of the mixture). To control the quality of the preparation of the mixture, 5-10% solutions of polyvinyl alcohol, GOST 10779-78, containing 15–20% of adherent groups suitable for binding and b combining with solutions of natural rubber: latex-quality, were prepared. catfish, latex-revoltex and latex SKI-3. To accelerate the dissolution of polyvinyl alcohol in a mixture of distilled water and a polyhydric alcohol (glycerin, ethylene glycol), the heterogeneous mixture was left to pre-swell the polymer for a day. Next, hydrophobization of polyvinyl alcohol was carried out: by preparing a prepared aqueous solution of polyvinyl alcohol with a calculated amount of (J-naphthalene sulfonic acid) for 30 s. at. A mixture of an aqueous solution with (i-naphthalene sulfonic acid) was filtered on a filter press at 100 ° C through 20 layers of fabric. To remove air bubbles, the filtered solution was stored in the collection for 2 days at.

The second part with:; you are prepared by successive dissolution in latek1, 33

1.33 0.48 0.48

1, 84

0.063

0.001

natural rubber (latex-qua-litex, latex-revoltex, latex

SKI-3), 2,2-methyl-bis-4-methyl-6-tert-butylphenol or phenyl-o-naphtylamine and castor oil. The prepared film-forming solution in a mixture with the indicated components at an appropriate ratio among themselves (see table, compositions 1-6) was filtered through 1-2 layers of a nylon mesh. At this time, the concentration and viscosity of the film-forming agent were controlled. Viscosity was tested on a VZH-1 or VZH-2 viscometer at 20 ° C.

Before use (i.e. deposited on the board), both parts of the mixture are mixed and a 25% aqueous ammonia solution is added as a buffer additive that regulates the pH of the mixture being made.

In the proposed composition for removing the formed protective film

the use of solvents is required because it (film) is removed by mechanical means, such as tweezers, in the shortest amount of time;

Research results have shown that this soldering composition, primarily to protect the metallized holes and the conductors of the printed circuit board from molten solder, when applied to the surface quickly forms a protective film, which is removed by small forces after soldering. The use of this composition significantly improves performance

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assembly and installation work and the quality of manufactured units and blocks of electronic equipment.

Claims (3)

Invention Formula I. Soldering composition, mainly for protecting metallized holes and Conduits of printed plates from molten solder, containing rubber, castor oil, characterized in that, in order to improve the quality of protection and reduce the complexity of the soldering process by reducing the adhesion of the protective film to conductors and PCB material, it additionally contains distilled water, dibutyl phthalate, 2,2-methylene bis-4-metsh-6-tert-butylphenol or phenyl - (/ - naphthylamine, 25% aqueous solution of ammonia, polyvinyl alcohol, glycerin or ethylene glycol and j3-naphthalene ulcer, and as rubber - water suspension - latex at the following ratio of components, wt.%: Natural rubber latex 78,10- 91.59 n 4.57-7.81 1.74-4.95 0.87-3.37 1..402-2,400 0.48-2.17 0.25-0.87 0.063-0.304 0,001-0,026 2. The composition of claim 1, which is different from the fact that it contains industrial oil instead of castor oil. 3. The composition of paragraphs. 1 and 2, of which, in order to make a visual assessment of the removal of the composition, it contains rhodamine C or a water-soluble polygraphic dye in an amount of 1-3% by weight.