JPS63160798A - Binder for paste solder - Google Patents

Abstract

PURPOSE:To prevent corrosion of solder powder and oxidation of base metals and to improve soldering workability by mixing respectively prescribed % of PE and org. gelling agent with specific weight % of n-octane. CONSTITUTION:The binder for paste solder is obtd. by mixing 40-80%, by weight, PE with 20-60% n-octane, further adding 0.25-3% org. gelling agent thereto, and agitating and heating the mixture. The org. gellint agent effectively acts as a viscosity control agent to prevent the corrosion of the solder during storage and to prevent the oxidation of the base metals at the time of coating if the paste solder is prepd. by adequately mixing and agitating this binder and the solder powder. The splashing of the binder during soldering and the formation of residue are obviated and, therefore, the soldering workability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a paste solder binder used for brazing in a non-oxidizing atmosphere.

(Prior Art and its Problems) Conventionally, brazing of base materials that are extremely susceptible to oxidation has been carried out in a non-oxidizing atmosphere such as a vacuum or a reducing atmosphere. As the brazing material used in this case, a paste brazing material made by mixing a brazing powder and a binder has recently been adopted.

The brazing filler metal that is the main component of this paste solder is made by powdering known brazing filler metals, such as △uNi wax powder, t's
, g Cu wax powder, AgPd wax powder, etc. are used, but the binder is required to have the following properties.

(1) No residue such as carbon remains when used in a non-oxidizing atmosphere.

(2) It should not separate from the wax powder and form two layers during storage.

(3) Do not corrode the wax powder.

(4) Do not oxidize the base material to be brazed.

(5) Brazing should not get wet or run off from the part.

(6) Do not splash during heating.

(7) Good workability.

In other words, as a binder for paste solder, it is desirable that it is non-corrosive, has a viscosity that does not easily evaporate at room temperature, and that does not separate and evaporate within 450°C during brazing and does not splatter or leave any residue. It is rare.

However, none of the binders used in conventional paste soldering satisfies the above conditions.

Therefore, the present inventors believe that in order to satisfy the above conditions required for a binder composition, it is not necessary to separate the polymeric material having a certain molecular weight, its solvent, and the wax powder, which has a heavy specific gravity when made into a paste. Focusing on the need for a viscosity modifier to impart viscosity to the binder, we conducted research on polymeric materials, solvents for dissolving them, and viscosity modifiers, and found that n-octane, polyethylene, and viscosity modifiers We have discovered a binder for wax paste that satisfies the above conditions by combining it with an organic gelling agent.

(Means for solving the problems) The binder for wax paste of the present invention has n-octane 2
It is made by mixing 0 to 60 wt% of polyethylene, 40 to 80 wt% of polyethylene, and 0.25 to 3 wL% of an organic gelling agent.

The reason why 20 to 60 wt% of n-octane is used as a solvent in the binder for wax paste of the present invention is to improve workability and volatility.
- If it is less than 1%, it will easily separate from the wax powder during storage and form two layers, and if it exceeds 60 wt%, it will easily volatilize (this is because it becomes difficult to stick the wax powder).

The reason why the proportion of polyethylene was set at 40 to 80 wt% is as follows.
If it is less than 40wL%, when it is mixed with wax powder and made into a paste, brazing has poor wettability to the part, and sufficient brazing cannot be achieved, and if it exceeds 80wL%, the wax powder will separate during storage, resulting in two layers This is because it becomes unsuitable as a binder. The reason why the organic gel was set at 0.25 to 3 wt% is that 0.25 to 3 wt% was used.
If it is less than 25 wt%, it will not gel, so when mixed with wax powder and made into a paste, the binder and wax powder will separate into two layers, and if it exceeds 3 wt%, the gelling effect will be strong and solidify, so the binder It can no longer be used as such.

Next, examples of the binder for paste brazing according to the present invention will be described.

(Example) After 45 wt% of n-octane was mixed with 531% of polyethylene, leosin (CA) was added as an organic gelling agent.
STOROIL COMPΔNY! ! After mixing 2+d% of the mixture and stirring thoroughly, the mixture was heated in a hot water bath at 45°C ± 5°C for 1 hour, and then left to cool in the air to room temperature to gel.
Made with an agar-like binder.

A paste wax was prepared by mixing and stirring 901% of a wax powder with A u N i of 18% to 10% of the agar-like binder of the example thus prepared.

In this paste wax, the wax powder and binder did not separate during storage, and the wax powder did not corrode.

However, when this paste solder was applied to the base material of the iron piece and was repeatedly brazed at 970° C. in a hydrogen atmosphere, good brazing was achieved without any residue such as carbon.

On the other hand, Darpo Blaze qrAp45 of conventional example 1
14 paste wax and conventional example 2 using Niclo Blaze Cement S manufactured by Wall Kono Monoi (mixed and stirred with 10-1% of Klo Blaze Cement+-S binder and 901% of AuNi 18% wax powder). During storage, the wax powder and binder separated, and the wax powder in the paste wax of Conventional Example 1 corroded. When these conventional brazing pastes were applied to the base material of an iron piece and laminated and brazed at 970° C. in a hydrogen atmosphere, residues such as carbon were produced and the quality of the brazing was poor. Also, conventional example 2
The paste wax sputtered during heating.

(Effects of the Invention) As can be seen from the above explanation, if the binder for paste brazing of the present invention is appropriately mixed and stirred with wax powder to make a paste wax, the wax powder will not separate during storage and will not corrode the wax powder. In addition, over-brazing does not oxidize the base material when applied to the base material, and does not splatter during heating for brazing, and can be used for brazing in non-oxidizing atmospheres. This has the excellent effect of producing a paste wax that does not produce residues such as carbon.

Claims (1)

[Claims] 20-60wt% n-octane, 40-40wt% polyethylene
A binder for paste soldering comprising a mixture of 80 wt% and an organic gelling agent of 0.25 to 3 wt%.