Flux-containing compositions for brazing aluminum, films & brazing method thereby

• US 20020005230A1
• Filed: 02/15/2001
• Published: 01/17/2002
• Est. Priority Date: 02/17/2000
• Status: Active Grant

• Current Assignee: Toyo Aluminium Kabushiki Kaisha (Nippon Light Metal Holdings Co., Ltd.)
• Original Assignee: Toyo Aluminium Kabushiki Kaisha (Nippon Light Metal Holdings Co., Ltd.)
• Inventors: Kikuchi, Ken, Watsuji, Takashi, Matsumura, Ken, Katou, Haruzou
• Granted Patent: US 6,497,770 B2
• Time in Patent Office: Days
• US Class Current: 148/23
• CPC Class Codes: B23K 35/025 Pastes, creams, slurries
• CPC Class Codes: B23K 35/286 Al as the principal constituent
• CPC Class Codes: B23K 35/288 with Sn or Zn
• CPC Class Codes: B23K 35/3605 Fluorides
• CPC Class Codes: B23K 35/3613 Polymers, e.g. resins

Abstract

A flux-containing composition for brazing aluminum comprising:

(a) a fluoride flux,

(b) at least one binder selected from the group consisting of an alkyd resin, a mixture of an acrylic resin and a butyl rubber (or a petroleum resin), and a polyethylene resin,

(c) an organic solvent, and optionally

(d) a metallic powder for brazing.

The flux-containing composition of the present invention for brazing aluminum is easy for handling and plastic working of a product coated therewith, gives brazed areas (fillets) of good appearance and has low costs and better operating environment, and capable of applying members having complicated shapes.

Claims

1. A flux-containing composition for brazing aluminum comprising:

a) a fluoride flux;

b) at least one binder selected from the group consisting of an alkyd resin, a mixture of an alkyd resin and a butyl rubber, a mixture of an alkyd resin and a petroleum resin, a mixture of an alkyd resin, a butyl rubber and a petroleum resin;

a polyethylene resin, a mixture of a polyethylene resin and a butyl rubber, a mixture of a polyethylene resin and a petroleum resin, a mixture of polyethylene resin, a butyl rubber and a petroleum resin;

a mixture of an acrylic resin and a petroleum resin, a mixture of an acrylic resin and a butyl rubber, a mixture of an acrylic resin, a petroleum resin and a butyl rubber;

wherein the butyl rubber has a molecular weight in the range from 250,000 to 550,000; and

c) an organic solvent.

2. The flux-containing composition of claim 1, wherein the composition further includes d) a metallic powder for brazing.

3. The flux-containing composition of claim 2, wherein the metallic powder for brazing is at least one member selected from the group consisting of an aluminum powder, a silicon powder, a zinc powder and an alloy powder thereof.

4. The flux-containing composition of any one of claims 1 to 3, wherein the butyl rubber comprises a copolymer of isobutylene and isoprene.

5. The flux-containing composition of any one of claims 1 to 4, wherein the fluoride flux is at least one compound selected from the group consisting of AlF₃-KF, KAlF₄-K₃AlF₆, K₃AlF₆ and KAlF₄.

6. The flux-containing composition of any one of claims 1 to 5, wherein the composition further includes a coupling agent.

7. The flux-containing composition of any one of claims 1 to 6, wherein an amount of the fluoride flux is 2 to 70% by weight, an amount of the binder is 0.1 to 15% by weight, an amount of the metallic powder is 10 to 70% by weight (if any), and the balance is the organic solvent provided that the total is not more than 100% by weight.

8. An aluminum material coated with the flux-containing composition of claim 1 or any one of claims 3 to 7 onto at least a part of a surface of an aluminum brazing sheet.

9. An aluminum material coated with the flux-containing composition of any one of claims 2 to 7 onto at least a part of its surface.

10. A method of brazing an aluminum material comprising:

coating at least a part of a surface of the aluminum brazing sheet with the flux-containing composition of claim 1 or any one of claims 3 to 7; and

brazing the aluminum brazing sheet with any other aluminum material by heating.

11. A method of brazing an aluminum material comprising:

coating at least a part of a surface of the aluminum material with the flux-containing composition of any one of claims 2 to 7; and

brazing the aluminum material with any other aluminum material by heating.