KR20000062088A - Soldering Flux Composition - Google Patents

Abstract

PURPOSE: A brazing flux composition is provided to weld a metal material having difficulty in welding with a low-temperature welding material such as Pb-Sn groups or Ag-Sn groups by employing a simple electric iron. CONSTITUTION: A brazing flux composition consists of, by weight %: 20-60% of a phosphoric compound, 10-30% of organic acid, 1-20% of an 8-group transition element and 5-30% of a viscosity improver. The composition is applied widely to common lives and industrial fields as well as electric, electronic, fine-tube processing and thin-film welding fields.

Description

Soldering Flux Composition

The present invention relates to a soldering flux composition, and more particularly, in the electrical and electronics industry, it is possible to easily weld a material that is difficult to attach by welding materials such as stainless steel, copper, zinc, tin, and a thick iron plate. To a flux composition.

In general, stainless steel is a common material and is also used for daily or industrial purposes. It has a high strength, does not rust and gloss does not change, it is used in a variety of products from home appliances, building materials to industrial materials. The joining between these stainless steel products is mainly using argon welding or welding using oxygen and acetylene torch to obtain a clean welding part, and some arc welding is used. In addition, in the case of a mechanical product including a heat exchanger, a copper pipe having excellent thermal conductivity is used inside, and a stainless steel plate is used outside. In this case, argon welding is used, but silver welding is sometimes performed to increase the sealing property.

Argon welding has a relatively good welding surface, but it causes great damage to eyes and skin during welding, and argon must be continuously consumed besides the welding rod. Therefore, the cost of welding is very high due to labor cost and material cost, and it is a hot melt welding of more than 1500 ℃. Therefore, stainless steel has a fatal defect that causes a problem in the welding area and loss of both rust and gloss due to stress generation during welding and changes in stainless steel components. In the case of silver soldering, the damage of the human body during welding is not so large, but the electrode itself price is too expensive because the silver content of the electrode is 40-95%, and it is lower than that of argon welding because the welding method uses a high-temperature spark. However, since it is welded at a high temperature of more than 800 ℃ affects the base material, in the case of copper products, there is a problem that corrosion resistance is less reduced, but in the case of stainless steel is corrosion resistance is lost.

In order to solve this problem, the low-temperature, low-cost lead-tin or silver-tin low-temperature wire (welding material), using a low-temperature welding iron electric iron using stainless steel- stainless steel, stainless steel Attempts to weld steel-tin, stainless steel-copper, stainless steel-iron, stainless steel-zinc, zinc-copper, zinc-iron, copper-copper, tin-tin, iron-tin, and copper-tin have been previously sought after ), But no suitable welding flux has been developed.

The composition of the low temperature welding flux depends on the type of welding material and the welding temperature (electric iron or brazing), but the composition of the most common flux and the role of the components of the lead-tin or silver-tin welding materials commonly used. Is as follows.

Rosin: 30-70 wt%

Solvent: 20-50 wt%

Viscosity regulator: 1 to 10 wt%

Activator: 0.01 to 1% by weight

Acid: 0.1-1 wt%

Rosin: Abietic acid, the active ingredient in rosin, removes oxides at the junction at high temperatures, improves spreadability and adhesion to the base material of the flux, and helps to block oxygen from the air. These include gum rosin, tolosin, wood rosin, hydrogenated rosin and esdel gum.

Solvent: Dissolves solid rosin, remaining liquid component and solid component to make it uniform and does not leave residue after evaporation during welding. Types include butyl cellosolve, 1,3-butanediol, butyl carbitol, hexane carbitol and the like.

Viscosity Modifier: Provides proper flow prevention and adhesion and improves work efficiency. Types thereof include castor wax, higher fatty acid amides, hardened castor oil, and the like.

Active agent: Halogen element generated by decomposition at high temperature shows activity and helps to close adhesion and melting between welding material and base material. It is generally composed of hydrochloric acid or bromate of aliphatic amines, and examples thereof include ethylamine hydrochloride and dimethylamine bromate.

Acid: Helps rosin's abietic acid. Types include fumaric acid, tartaric acid, and phthalic acid.

The general flux is mostly used for iron plate-steel plate, galvanized steel plate-zinc steel plate, and it leaves a brown residue when welding. When preheating is insufficient, the weld strength is significantly decreased and the weldability is poor.

In particular, in recent years, it can be seen that there are many inventions related to the cream solder for electronic and circuit boards in which the low temperature welding material is included in the flux, rather than the general welding flux.

British Patent No. 2 278 370 discloses a composition of flux containing zinc chloride, non-oxidizing acids such as tin chloride, hydrochloric acid, viscosity modifiers such as glycerol, polyethylene glycol and sorbitol. EP 0 619 162 discloses flux compositions comprising bis (2-oxazoline) compounds, dichiol compounds, organic carboxylic acid compounds and activators. U.S. Patent No. 5,281,281 is a flux that does not require post-cleaning and does not contain rosin, with at least 95% by weight of distilled water as a solvent and containing C ₂ -C ₁₀ dicarboxylic acids, monocarboxylic acids and oxy acids. A flux composition is disclosed. In addition, US Pat. No. 5,296,046 discloses solvents; A flux composition consisting of oxide scavengers such as 2-amino isophthalic acid and 5-amino isophthalic acid and compounds which generate nitrogen upon heating are disclosed.

In addition, Japanese Patent Laid-Open No. 5-337686 discloses a soldering flux containing 0.5 to 3% by weight of a silicon compound, and Japanese Patent Laid-Open No. 5-318176 discloses rosin-based cream solders such as maleic acid and benzoic acid. Japanese Patent Laid-Open No. 6-15483 discloses a composition containing benzimidazole, imidazole thiol compound, and triazole compound as a flux that does not leave a residue and does not cause corrosion at a soldering site for a long time. In addition, Japanese Patent Laid-Open No. 6-155078 discloses a rosin-based flux in which an alkylamine complex salt of boron trifluoride or an aromatic amine complex salt is added as an activator. Meanwhile, Korean Patent Publication No. 81-49 discloses a flux composition consisting of neutral esters derived from polyhydric alcohols, organic monocarboxylic acids, and activators instead of rosin, which is an essential component.

There are many other patents, but the multifunctional flux having a complex function pursued by the present invention has not been put into practical use or disclosed yet.

Accordingly, it is an object of the present invention to provide a multi-functional flux composition that enables welding of the above-mentioned difficult-to-weld metal material with a low temperature welding material such as lead-tin or silver-tin using a simple electric iron.

The composition of the present invention for achieving the above object is 20 to 60% by weight of phosphoric acid compound containing 50 to 60% by weight of phosphoric acid, 10 to 30% by weight of organic acid, 1 to 20% by weight of Group 8 transition elements and 5 to 5 viscosity regulators. 30 weight percent.

Looking at the present invention in more detail as follows.

Until now, tin-lead (70-20: 30-80) and tin-silver (95-30: 5-70) -based welding materials made of low melting point alloys are relatively inexpensive and can be easily operated by electric iron. It was an accessible welding means. However, its use range was limited to extremely thin and small tin plate, iron plate, copper plate, etc., and was not available for stainless steel, thick iron plate, and zinc plate.

The present invention relates to a flux composition of a new concept other than conventional rosin-based fluxes or ester-containing fluxes of polyhydric alcohols. The present invention relates to homogeneous or heterogeneous types of stainless steel, copper alloys, iron alloys and tin alloys, which have not been possible until now. It is to enable welding.

This is because it is not simply a soldering method of melting lead, but because a molten alloy due to a plus is formed between the base material and the welding material, a very strong welding part is formed. For example, when the stainless steel plate is placed on a thick iron plate having a thickness of 2 cm or more, only the multifunctional flux of the material of the present invention is used without any preheating, and there is no stress on the base material and no heat damage occurs. It is possible to instantaneously complete welding in the state.

As described above, the composition according to the present invention is 20 to 60% by weight of phosphate compound containing 50 to 60% by weight of phosphoric acid, 10 to 30% by weight of organic acid, 1 to 20% by weight of Group 8 transition elements and 5 to 5 viscosity regulators. 30 weight percent.

Preferred examples of the phosphate compound which is the main component of the present invention include, but are not limited to, ammonium phosphate, potassium phosphate, sodium phosphate or calcium phosphate. As the flux, the phosphoric acid compound preferably contains 50 to 60% by weight of phosphoric acid. This is because phosphoric acid does not have a high oxidizing power at room temperature, but the activity is increased when heated in a state where it is mixed with other constituents in the flux, and removes impurities and oxides on the surface of the base material and forms a reaction atmosphere. On the other hand, the amount of the phosphate compound is preferably 20 to 60% by weight, in which the amount is less than 20% by weight of the oxidizing power is reduced and the activity is weak, if the amount exceeds 60% by weight excessive brittleness and brittle to the soldering surface This can happen.

The organic acid used in the present invention tends to have coordination bonds with iron, copper or stainless steel and the like when heated with other flux compositions to activate the surface. The organic acid is selected from the group consisting of maronic acid, octylic acid, acetic acid and formic acid. The amount is preferably 10 to 30% by weight. If less than 10% by weight or more than 30% by weight, the filler material is entangled during soldering or the molten state becomes spherical, which causes poor welding.

The Group 8 transition element is preferably a nickel compound (for example, nickel carbonate, nickel chloride, or nickel hydroxide) or a palladium compound (palladium chloride, or palladium acetate), and the composition of the flux composition is 1 to 1 20% by weight is preferred. The Group 8 transition element plays an important role of forming a catalyst or an intermediate mediator to increase the bonding strength between the metals which are difficult to be affinity. If the amount is out of the amount used, the bonding between the metals is not well made or the adhesion is excessive, resulting in entanglement. Can be.

On the other hand, the viscosity modifier is used in the range of 5 to 30% by weight. The flux composition can be manufactured in liquid form, cream form or paste form by adjusting the adhesiveness and adhesiveness of the flux composition of this invention, and adjusting the compounding composition ratio of a viscosity modifier. Examples of the viscosity modifier include paraffin oil, castor wax, polyvinyl alcohol (PVA) resin, high fatty acid amide, manganese oxide, titanium oxide, acetone, and / or isopropyl alcohol. Outside the range of the amount used, the flux composition may not be in a good state, and may leave residues on the soldering surface or become vulnerable and degrade durability.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples. In the following examples, the unit "%" means "% by weight" unless otherwise noted.

Example 1

The flux composition was prepared by uniformly mixing 50% potassium phosphate, 10% nickel carbonate, 20% octylic acid and 20% acetone at a heating temperature of about 50 ° C.

Example 2

Flux compositions were prepared in the same manner as in Example 1 except that 60% potassium phosphate, 10% nickel chloride, 20% maronic acid, and 10% isopropyl alcohol were used.

Example 3

Flux compositions were prepared in the same manner as in Example 1, except that 40% sodium phosphate, 20% palladium chloride, 20% acetic acid and 20% paraffin oil were used.

Example 4

Flux compositions were prepared in the same manner as in Example 1 except that 20% calcium phosphate, 20% palladium acetate, 30% formic acid and 30% castor wax were used.

Example 5

Flux compositions were prepared in the same manner as in Example 1 except that 50% ammonium phosphate, 20% nickel hydroxide, 10% octylic acid and 20% high fatty acid amide were used.

Example 6

Flux compositions were prepared in the same manner as in Example 1 except that 50% calcium phosphate, 10% palladium acetate, 10% maronic acid, and 30% titanium oxide were used.

Examples 1 to 3 are liquid flux compositions, and Examples 4 to 6 are cream or paste compositions.

As a result of soldering using the flux composition of the above embodiment, no residue was generated and no mist was generated, the soldering performance was excellent even in wet conditions, the weld coating was completely tightly bonded, and the anticorrosive action during soldering in the manufacturing of the printed circuit assembly was performed. After soldering, no post-treatment was necessary. In addition, it has a wide range of applications and is superior to other flux compositions, and has technical advantages over conventional flux compositions, and cream and paste forms transparent residues when soldering to facilitate inspection of joints and improve vibration resistance of joints. In addition, the elastic transparent residue had resistance to high temperature and had an advantage of preventing oxidation.

As described above, the composition according to the present invention does not require preheating of the base material, and because of its characteristics, welding of thick base materials or thick plates and thin plates, plates of different types and properties, is easily performed, thus increasing productivity and enabling the production of a new method. . The manufacturing method of the product, which has been possible only by argon welding, arc welding, or high temperature flame welding, can be economically and productively made with the composition according to the present invention, thereby achieving generalization of high-quality products. It can be applied to a wide range of everyday life and industrial fields, as well as customs and thin plate welding. In addition, even when lead (Pb) is prohibited due to the harmfulness to the human body, silver-tin (5-70: 95-30) -based welding agent may be used. Because of its ability to lower, it is possible to use it, which makes it possible to use silver-tin welding agent having a higher melting point than lead-tin.

Claims (5)

A solder comprising 20 to 60% by weight of a phosphate compound containing 50 to 60% by weight of phosphoric acid, 10 to 30% by weight of an organic acid, 1 to 20% by weight of a transition group 8 and 5 to 30% by weight of a viscosity modifier. Flux composition. The brazing flux composition of claim 1, wherein the phosphate compound is ammonium phosphate, potassium phosphate, sodium phosphate, or calcium phosphate. The brazing flux composition of claim 1, wherein the organic acid is selected from the group consisting of maronic acid, octylic acid, acetic acid and formic acid. The brazing flux composition of claim 1, wherein the Group 8 transition element is a nickel compound or a palladium compound. The method of claim 1, wherein the viscosity modifier is selected from the group consisting of paraffin oil, castor wax, polyvinyl alcohol (PVA) resin, high fatty acid amide, manganese oxide, titanium oxide, acetone, and isopropyl alcohol. Soldering flux composition, characterized in that.