JPH06315789A - Aluminum solder paste for torch brazing - Google Patents

Abstract

PURPOSE:To provide the aluminum paste for torch brazing which does not emit smoke, soot, malodors and residual carbons, retains the initial properties without deterioration during preservation and has excellent applicatability. CONSTITUTION:The aluminum solder paste for torch brazing of aluminum members is formed by incorporating 30 to 150 pts.wt. org. solvent into 100 pts.wt. aluminum alloy powder having 10 to 500mum average grain size, 80 to 200 pts.wt. flux and 0.5 to 10 pts.wt. org. high-polymer binder consisting of polyalkylene oxide as a main constituting component and having 100000 to 5000000 average mol.wt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum brazing paste in which aluminum members can be easily joined in the air by using a torch. As used herein, the term "aluminum" includes various aluminum alloys unless otherwise noted.

[0002]

2. Description of the Related Art Brazing methods are roughly classified into torch brazing and furnace brazing. Since brazing between aluminum members has little difference in melting point between the brazing material and the aluminum members, in-furnace brazing, which allows easy temperature control, is generally adopted. In-furnace brazing is generally performed in a nitrogen gas atmosphere, but since torch brazing is performed in an oxidizing atmosphere in the atmosphere with a torch burner or high-frequency brazing, when using a conventional brazing paste for in-furnace brazing Aluminum that can be put into practical use due to the deterioration of the work environment, the poor appearance of the finish, the poor brazing, etc. due to the generation of flames, soot, malodors, charcoal residue, etc. and white smoke resulting from the organic substances compounded as a binder inside. Wax paste has not been developed.

However, brazing in a furnace, which requires a large-scale apparatus, has a large demerit in practical use, and it has been desired to develop a brazing technique between aluminum members by torch brazing and an aluminum brazing paste that can be used for this. .

In recent years, as a flux material, a non-corrosive, non-water-soluble aluminum fluoride-based flux has been developed in place of the conventional chlorine-based flux (for example, Japanese Patent Laid-Open No. Sho 5).
1-123749, JP 56-6797, JP 58-27037, and JP 62-46.
280, JP-A 5-2434, etc.). Since this aluminum fluoride-based flux has almost no corrosiveness and hygroscopicity as compared with the conventional chlorine-based flux, a method of kneading this with aluminum alloy powder and water immediately before use and using it for torch brazing has also been tried. However, since water is used, it easily reacts with the aluminum alloy powder and has no storability, which is very inconvenient.

As mentioned above, most conventional aluminum brazing pastes have been developed for furnace brazing, and when this formulation is applied to torch brazing, a large amount of soot is generated, and residual carbon, voids, odors on flames, and white smoke are generated. Various problems such as occurrence of.
Moreover, since it is for brazing in a furnace, the amount of flux is small and it is not suitable for torch brazing.

Various polymers have long been disclosed as binders for brazing pastes. For example, JP-A-56-6797 discloses hydroxypropyl cellulose, and JP-A-57-50598 discloses a molecular weight of 2.
000-40,000 polyalkylene glycols or polyalkylene glycol derivatives are disclosed in JP-B-63-4.
JP 3200 discloses a vehicle comprising at least one of an ethylene oxide polymer, a polyacrylate polymer, a polymethacrylate polymer, a polyacrylonitrile polymer, polyethylene glycol and its methyl ethers, and an aliphatic hydrocarbon polymer. Japanese Patent Publication No.-268995 discloses polyisobutylene, polybutene and the like. Of these, cellulosic polymers such as hydroxypropyl cellulose are carbonized or burn with a fire,
Black oil smoke is generated, and acrylic resin generates monomers with high irritating odor due to thermal depolymerization, which is a problem in terms of work hygiene.Polybutene-based flames burn when torch brazing in the atmosphere, and black oil smoke is generated. There are drawbacks such as occurrence of.

Further, JP-A-57-50598 describes that polyalkylene glycol or a derivative thereof is used for brazing copper powder. However, since this brazing is copper powder, flux should not be used. It uses water without water. The molecular weight of polyalkylene glycol is 2000-400000.
It is stated that the residual carbon after calcination is unavoidable if the molecular weight is higher than 0. The above-mentioned Japanese Patent Publication Sho 6
No. 3-43200 discloses the use of ethylene oxide polymers, which only has a long shelf life when using a highly viscous anhydrous vehicle and an anhydrous flux, the flux used is chloride free. Cleaning is essential because the residue after brazing corrodes aluminum. Japanese Examined Patent Publication No. 60-43200 makes no mention of the use of organic solvents or torch brazing.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aluminum brazing paste which can be brazed with a torch.

[0009]

The present invention has an average particle size of 10 to 10.
100 parts by weight of 500 μm aluminum alloy powder, 80 to 200 parts by weight of flux, 0.5 to 10 parts by weight of an organic polymer binder having polyalkylene oxide as a main constituent and an average molecular weight of 100,000 to 5 million, and organic solvent 30
To 200 parts by weight of aluminum brazing paste for torch brazing of aluminum members.

The composition of the aluminum alloy brazing powder used in the present invention may be any aluminum alloy having a melting point lower than that of the aluminum members to be joined. For example,
Aluminum-silicon (5-15%) system, aluminum-silicon (5-15%)-X system (X contains at least one of copper, magnesium and zinc), and bismuth, tin, barium as a third additive element. Can be included. Further, aluminum-copper alloy powder can be used. Zinc powder, tin powder, barium powder or the like may be mixed with the aluminum alloy brazing powder.

The average particle diameter of the above wax powder is 10 to 500.
μ, preferably 40 to 150 μ, and if it is less than 10 μ, the specific surface area of the powder becomes excessively large and the amount of the oxide film increases, so that it becomes difficult for the powder particles to be sufficiently fused and integrated with each other. When it exceeds, not only the powder is difficult to disperse and suspend in the paste, but also the gap between the powders becomes too large, which makes it difficult to perform a dense brazing.

The oxygen content of the aluminum alloy powder is preferably 0.2% by weight or less, more preferably 0.1% by weight.
It is the following. This is because when the amount is more than 0.2% by weight, the oxide film becomes thick, and in the case of aluminum, the oxide film is particularly strong, so that 200 parts by weight or more of flux necessary to destroy the oxide film must be added. However, if the flux is added in excess of 200 parts by weight, the proportion of the metal braze in the aluminum braze paste will decrease, and the amount of the metal braze will be insufficient and the brazing appearance will become dirty due to flux residue, etc. However, it is inconvenient and adversely affects the working environment. The shape of the aluminum alloy powder is not particularly limited, and as such a metal powder, various shapes such as a needle shape, a plate shape, a flat shape, a granular shape, an adjacent piece shape, and a flake shape can be used.

For example, a spherical or irregularly-shaped atomized Al alloy powder produced by atomizing in a non-oxidizing atmosphere is exemplified. Depending on the particle size and shape of the metal powder and the properties of the surface oxide film, if the oxygen content exceeds 0.2%, the surface oxide film does not break and does not melt and integrate even if it is suitable for the brazing temperature. In such a case, brazing itself is possible if the amount of flux used exceeds 200 parts by weight, but the ratio of the metal braze in the aluminum braze paste decreases, and the amount of metal braze becomes insufficient. A large amount of white residue and black spots are generated on the attachment part, and pollution and corrosion problems in the vicinity are caused.

In the present invention, a fluoride type flux is used as the flux. The fluoride system mentioned here is a flux containing fluorine and aluminum, and the component is A
_{lF 3 -KF, KAlF 4 -K 3} AlF 6, K 3 AlF 6, KAl
Fluoride-based fluxes such as F ₄ , KF-AlF ₃ -Al ₂ O ₃ and CsxAlyFz are exemplified. Commercially available "NOCOLOK" as a fluoride-based flux (manufactured by Alcan of Canada)
Is water-insoluble, non-corrosive, and has a merit of thickening because it is a fine powder, and is particularly preferable.

It is necessary to use a larger amount of flux in the aluminum brazing paste for the torch than in the case of brazing in a furnace. Therefore, when the chloride-based flux that has been conventionally used for brazing in a furnace is used for a torch, the hygroscopicity of the chloride-based flux reduces the storage stability of the brazing paste. Also, when a chloride-based flux is used, it will corrode unless the brazed part is cleaned after brazing. Therefore, a fluoride-based flux is particularly preferable for the aluminum brazing paste for a torch.

The fluoride type flux can be made into fine powder. The finely divided fluoride-based flux increases the viscosity of the vehicle (herein, referred to as a mixture of an organic polymer binder and an organic solvent) by using a large amount, and even without using a large amount of the organic polymer binder. ,
A brazing paste with the desired viscosity can be obtained.

The viscosity of the vehicle is preferably 30,000 c
It is ps (20 ° C.) or less, and it is unexpected that not only the productivity of the brazing paste is improved, but also the usability of the brazing paste, particularly the coating property is significantly improved.

When copper, silicon, or magnesium is contained as a component of the material to be brazed, the melting point of the material to be brazed becomes low, so that it is necessary to lower the working temperature of the flux. To lower the working temperature of the flux, Cs, Sr, Ba, Zn,
It is effective to contain Cu, and examples of the method include fluorides, oxides, etc. alone, mixed, and reaction products, and there is no limitation on the addition technique thereof, and they are included in the technical scope of the present invention.

The amount of the above-mentioned flux compounded is 80 to 200.
When the amount is less than 100 parts by weight, preferably 100 to 150 parts by weight, and 80 parts by weight, it is difficult to obtain a sufficient flux effect by torch brazing in the air, and it is wasteful to increase the amount to more than 200 parts by weight. In addition, the amount of metal braze in the aluminum braze paste is reduced, resulting in an insufficient amount of metal braze or a large amount of white residue or black spots on the fillet surface, resulting in poor product appearance and contamination in the vicinity. It will cause problems such as corrosion and corrosion.

The organic polymer binder used in the present invention contains polyalkylene oxide such as polyethylene oxide, polypropylene oxide and polybutylene oxide as a main constituent component in the molecule, and has an average molecular weight of 100,000 to 5,000,000, preferably 100,000. ~ 1.5 million high molecular weight compounds. In the present invention, it is important to use a high molecular weight organic polymer binder.

If the molecular weight is less than 100,000, sufficient viscosity will not be obtained unless a large amount of the polymer is used in the compounding, and the viscosity of the paste will be deteriorated due to the hydroxyl groups. On the other hand, if the molecular weight is too large, the spinnability becomes too strong, and the viscoelastic properties deteriorate.

The above organic polymer binder may be a homopolymer of the same alkylene oxide or a block or random copolymer of the different alkylene oxide as long as it is a high molecular weight compound. More preferred organic polymers are polyalkylene oxide compounds obtained by addition-polymerizing lower alkylene oxides such as ethylene oxide to organic compounds having two or more active hydrogen groups, polyvalent carboxylic acids, their anhydrides or their lower alkyl esters. Alternatively, it is a high molecular weight compound obtained by reacting with diisocyanate. At the end of the molecule, in addition to the hydroxyl group, has an alkoxy group, a carboxyl group or an ester group,
The molecule has an ester bond and a urethane bond in addition to the ether bond.

As the organic compound having two or more active hydrogens, ethylene glycol, propylene glycol,
Examples thereof include polyhydric alcohols such as 1,3-butylene glycol and hydrogenated bisphenols and polyhydric phenols such as bisphenol dihydroxypropyl ether. Further, as the polyvalent carboxylic acid, maleic acid, fumaric acid,
Examples thereof include succinic acid, glutaconic acid, adipic acid, sebacic acid, isophthalic acid, terephthalic acid and trimellitic acid.

Regarding the aromatic carboxylic acid, generation of residual carbon was observed on the surface of the brazing material during the brazing process. The types of carboxylic acid and the amount of residual carbon were in the order of succinic acid <adipic acid <phthalic acid.

As the polyalkylene oxide used in the present invention, not only general addition polymerization but also those obtained by polymerization reaction using a Ziegler-Natta catalyst in a suitable organic solvent can be applied.

The polyalkylene oxide produced by the polymerization reaction using the Ziegler-Natta catalyst is Ti.Al.
・ Zn ・ Si, etc. with less metal impurities are preferable.
% Or less, preferably 1000 ppm or less. This type of polymer is an odorless and nontoxic substance, stable against oxygen, ozone, acid, alkali and ultraviolet rays, and
Viscosity when dissolved in solvent is 200-30,000cps at 23 ℃
Since the above liquid is obtained, the coating operation becomes easy. Further, since it completely decomposes and volatilizes at about 200 to 350 ° C. in air and at about 300 to 400 ° C. in a nitrogen atmosphere, no carbonization residue is generated after brazing. The organic polymer in the above paste is preferably 0.5 to 10%, more preferably 1 to 8%. If the organic polymer content is less than 0.5%, the effect as a binder is poor, and if it exceeds 10%, it becomes too hard and does not become a paste, and the amount of burning polymer increases and the usability of torch brazing work is improved. become worse.

The amount of vehicle in the paste depends on the type and molecular weight of the organic solvent and binder, but is 30.5 to 210 parts by weight, more preferably 60 to 180 parts by weight, and especially preferably 60 to 180 parts by weight, based on 100 parts by weight of the aluminum alloy powder. It is preferably 80 to 120 parts by weight. If it is less than 30.5 parts by weight, it will not become a paste. If the amount exceeds 210 parts by weight, not only the brazing metal will be insufficient, but also problems of residual carbon and soot during brazing of the torch will occur.

Further, it is preferable that the organic solvent used in the present invention is not only safe and easy to handle by itself, but also does not generate soot and harmful gas when it is burned by heating the torch and has a good feeling in use. The torch brazing paste of the present invention can also be used for high frequency brazing. When used in this brazing method, a boiling point of 170 ° C. or lower, preferably 150 ° C. or lower, particularly preferably 130 ° C. or lower is preferable in order to prevent smoke generation during heating, and a solvent with a low latent heat of evaporation, surface tension, or polarity emits smoke. Hateful. From the viewpoint of toxicity, a propylene oxide adduct of lower alcohol is particularly preferable.

Further, the solvent needs to take into consideration various peculiarities of aluminum such that aluminum is an active metal. A polyalkylene oxide-based organic polymer having a molecular weight of 100,000 or more has low hygroscopicity, and the paste is less deteriorated than low-molecular glycols.

It is most important that the organic solvent does not absorb moisture or react. Furthermore, since the conditions of use of the paste are different, there are various cases in which it is desired to evaporate quickly, and it is preferable that the evaporation is slower. Therefore, a technique capable of providing a product suitable for it is desired.

Polyalkylene oxide is soluble in water, alkyl halides such as chloroform, carbon tetrachloride and trichlene and aromatic hydrocarbons such as benzene, toluene, xylene and anisole. However, water and alkyl halides have the advantage of not burning, but may react with aluminum.

Further, aromatic substances such as benzene, toluene and anisole generate soot during combustion. In addition, alcohols such as methanol, ethanol, propanol, and butanol can be used as the solvent because they dissolve the polymer when heated, but lower alcohols absorb moisture, have high volatility, have a strong odor, etc. , Has the drawback of reacting with aluminum. Also, C
A solvent having a linear hydrocarbon chain of 6 or more produces soot when heated.

The paste using the esters has a drawback that its reactivity is low in the low level, and residual carbon and soot are observed in the high level. Ethyl acetate, methyl ethyl ketone, acetone, THF, and diethyl ketone do not produce soot at the time of combustion, but vaporize too quickly to show good characteristics. Also,
Soot is observed to be generated during combustion of diisobutyl adipate, methyl isobutyl ketone, phthalic acid ester, and cyclohexanol.

The solvent of the present invention has 3 to 4 carbon atoms from the viewpoint of solubility of organic polymer binder, hygroscopicity, safety, soot and the like.
Those having an alkylene group or polyglycol thereof and monoethers thereof with lower alcohols (C1 to C4) are preferable. Particularly, alkylene glycols are ethers of C1-4 alcohols having a propylene residue, such as dipropylene glycol, tripropylene glycol,
Propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monoisopropyl ether, propylene glycol monobutyl ether, propylene glycol monoisobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol It can represent noethyl ether. The paste contains at least one selected from the above and / or a solvent selected from 1,4-dioxane. Propylene-based and ethylene-based solvents have paste viscosity stability and toxicity,
Inferior in terms of health and safety. Other than these, dibutylene glycol and the like are preferable.

Examples of suitable low boiling point solvents include 1,4-dioxane and dipropyl ether. These are volatile at room temperature and highly flammable, so caution is required when using them.

The amount of the solvent used is preferably 30 to 200 parts by weight, especially 60 to 150 parts by weight, based on 100 parts by weight of the aluminum powder, and the viscosity of the vehicle in which the organic polymer binder is dissolved in the solvent is 23,000 cps. It is particularly preferable to set it below 25,000 cps. By setting the vehicle viscosity to 30,000 cps or less, a paste without sagging or settling can be obtained when this is used as a paste.

A wax paste is prepared by using glycols, particularly dipropylene glycol, tripropylene glycol and their monoethyl ethers, monopropyl ethers, monobutyl ethers, dioxane, etc. as a solvent and polyalkylene oxide having a molecular weight of 100,000 or more as a binder. When it is made, it is possible to obtain particularly excellent coatability and fixability after coating. In that case, the amount of the organic polymer binder in the paste is 0.5 to 5 parts by weight with respect to 100 parts by weight of aluminum. The binder and the solvent may be used as a mixture of two or more kinds.

In order to adjust the coating workability and the like of the aluminum brazing paste according to the present invention, an organic viscosity modifier or a diluting solvent is added just before use. You may mix | blend suitably with this paste within the limit which does not impair. The viscosity of the brazing material of the present invention is adjusted according to the coating method. For brushing, for example, it is suitable to use a slightly viscous source-like suspension solution, which will not precipitate aluminum alloy wax powder without stirring or addition of an antisettling agent. , It cannot be applied uniformly. As described above, there are various methods of applying the suspension solution, and the optimum viscosity differs depending on the application equipment. Therefore, each solvent described in the text can be used as the solvent for forming the suspension solution.

The viscosity may be adjusted by using a viscosity adjusting agent, but the amount is 20 with respect to 100 parts by weight of the aluminum powder.
It is not more than 5% by weight, preferably not more than 5% by weight. Preferred viscosity modifiers are 12-hydroxystearic acid,
Examples of the wax include synthetic wax, paraffin wax, microcrystalline wax, polyethylene wax, hydrogenated oil, hydrogenated castor oil, fatty acid amide and polyamide, and polyethylene wax and hydrogenated castor oil are particularly preferable. The viscosity of the aluminum brazing paste according to the present invention may be appropriately selected according to the application method of the paste and is not particularly limited, but is usually 5000 to 5
000000cps / 23 ° C, preferably 15000-30
It is 0000 cps / 23 ° C. The viscosity in this case is a value measured using a Brookfield viscometer.

The aluminum brazing paste according to the present invention may further contain conventional additives, if desired, in addition to the above-mentioned components. Such additives include antioxidants (such as BHT), corrosion inhibitors (such as benzotriazole), colorants (such as fluorescein and methyl orange), defoamers (such as silicone oil). It is illustrated.

[0041]

EXAMPLES The present invention will be described below with reference to examples. Examples 1 to 13 Aluminum braze pastes 1 to 13 according to the present invention were prepared according to the formulations shown in Table 1.

[0042]

[Table 1]

The footnotes in Table 1 are as follows. (1) Al-12% Si alloy powder (average particle size; 40 μm, oxygen content: 0.05%) (2) Al-12% Si alloy powder (average particle size; 70 μm, oxygen content: 0.02 %) (3) "NOCOLOK" (aluminum fluoride flux manufactured by Alcan Co., Ltd.) (4) Dai-ichi Kogyo Seiyaku Co., Ltd., a polyethylene oxide ester with a molecular weight of 100,000 (5) Dai-ichi Kogyo Seiyaku, a polyethylene oxide type with a molecular weight of 100,000 Esters (6) Polyethylene oxide with a molecular weight of 100,000 manufactured by Sumitomo Seika (7) Polyethylene oxide with a molecular weight of 400,000 manufactured by Meisei Chemical (8) Polyethylene oxide with a molecular weight of 360-4,000,000 manufactured by Meisei Chemical (9) Molecular weight of 400,000 manufactured by Sumitomo Seika 20% propylene residual ethylene oxide random polymer product of Table 1 shows the properties of the aluminum braze pastes 1 to 13 prepared by the above compounding recipe.

Comparative Examples 1 to 9 Aluminum brazing pastes 1'to 9'were prepared according to the formulation shown in Table 2.

[Table 2]

The footnotes in Table 2 are as follows. (1) Al-12% Si alloy powder (average particle size: 70 μm, oxygen content: 0.02%) (2) “Nocolok” (Alcan Co .: aluminum fluoride based flux) (3) 21% LiCl, 40% KCl, 22.5% NaCl,
9% LiF, 8.5% ZnCl ₂ (4) Liquid polyisobutylene Average molecular weight 500 (5) Polyethylene glycol molecular weight 10000 (6) Polyethylene glycol molecular weight 400

Table 3 shows examples 1 and 2 of Table 1 and Table 2
The vehicle viscosity, paste viscosity and usability of Comparative Examples 1'and 2'of are shown.

[Table 3]

The properties of the aluminum brazing pastes shown in Tables 1 to 3 are as follows.
2mm at the center of one side of the T-joint made as shown in FIG. 1 (top view) and FIG.
After attaching 60 mg, heating was performed with a propane burner.
The evaluation is as follows.

Metal residue ( residue of unmelted brazing metal powder) A: No excellent metal powder is found. B: Good There is a residue on about 10% of the surface. C: About 20% of the surface has a residue. D: No More than C. E: Not subject to evaluation (alloy powder hardens into cement without returning to brazing metal)

Appearance due to flux residue A: Excellent B: Good C: Possible D: Not possible E: Not evaluated

Wax fluidity (fillet formation rate) A: fillet formation rate 100% B: fillet formation rate of 80% or more and less than 100% C: fillet formation rate of 50% or more and less than 80% D: fillet formation rate of less than 50% E: Not evaluated (does not melt)

Fillet shape (fillet thickness) A: Most of the brazing metal gathers in the fillet and draws an arc with optimum tension. B: About 70% of A fillets are formed. About 30% of C: A fillets are formed. D: Does not form a fillet. E: Not subject to evaluation (does not melt)

Storability of paste (separation of paste after 1 month at 25 ° C.) A: Not separated B: Vehicle bleeds on the upper surface of paste C: Separation of vehicle is less than 10% D: Separation of vehicle is less than 20% E: 20% or more of the vehicle separates

Viscosity change A: Smooth paste state, less than 10% viscosity change B: No smoothness, no crushing, 50% viscosity change
Less than% C: A small lumpy fluff occurs and the viscosity change is 100%
Less than D: crushed bean paste, viscosity change is 100% or more E: Solid

Corrosion after corrosive brazing (96 h) A: No corrosion is observed even when treated at a temperature of 40 ° C. and 90%. B: Discolored by a temperature treatment of 40 ° C and 90%. C: The color changes in the indoor environment. D: Both the base metal of the brazing material corrode in the indoor environment. E: Not applicable for evaluation (cannot be judged as cement without cementing)

Odor A: Not noticeable B: There is a peculiar odor C: There is an unpleasant odor D: Unpleasant odor E: Not evaluated

Soot during brazing A: No output B: A little output C: More than B output D: A lot of soot cannot be used E: Not evaluated

Scatter A: Not scatter B: Scatter less than 5% C: Scatter less than 10% D: Scatter 10% or more E: Not evaluated

[0058]

The aluminum brazing paste according to the present invention has good storage stability (for example, at room temperature in air for about 6 to 20 months, metal powder and flux do not separate) and coating workability, and Exhibits excellent brazing properties. In the case of torch brazing aluminum members using the brazing paste, toxic gas or soot having strong irritating property is not generated, and no poor appearance, poor bonding or corrosion with time is observed at the joint, Excellent brazing of the components can be achieved without the need for additional heating steps.

[Brief description of drawings]

FIG. 1 is a top view of a T joint used for evaluating the properties of an aluminum brazing paste.

FIG. 2 is a front view of the T joint.

[Explanation of symbols]

 1 Aluminum test plate 2 Aluminum test plate 3 Sample paste

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location C08L 75/08 NFY 8620-4J C09D 171/02 PLQ 9167-4J (72) Inventor Tadashi Takemoto Osaka Prefecture 5-11-28-506 Kasuga-cho, Toyonaka-shi (72) Inventor Tatsuyuki Ue 3-6-8, Kutaro-cho, Chuo-ku, Osaka-shi, Osaka Toyo Aluminum Co., Ltd.

Claims (6)

[Claims] 1. An organic polymer binder having an average particle size of 10 to 500 μm, 100 parts by weight, a flux of 80 to 200 parts by weight, and an organic polymer binder having a polyalkylene oxide as a main constituent and an average molecular weight of 100,000 to 5,000,000.
Aluminum brazing paste for torch brazing of an aluminum member, containing 10 to 10 parts by weight and an organic solvent of 30 to 200 parts by weight. 2. The paste according to claim 1, wherein the organic polymer is an ester of polyalkylene oxide and / or urethane. 3. The paste according to claim 1, wherein the polyalkylene oxide derivative is a decomposition product caused by heat or radiation. 4. The paste according to claim 1, wherein the metal powder for aluminum brazing paste is an aluminum alloy powder having an oxygen content of 0.2% or less. 5. The aluminum brazing paste according to claim 1, wherein the flux is an aluminum fluoride type flux. 6. The organic solvent is dipropylene glycol,
Selected from tripropylene glycol, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, 1,4-dioxane The paste according to claim 1, which is one or more kinds.