| 摘要 |
An aluminum-extruded multi-cavity flat tube for use in an automotive heat exchanger having excellent brazing characteristics that make it possible to dispense with a flux coating step when assembling a heat exchanger component, or to use an aluminum fin not clad with brazing metals in place of a brazing sheet, as enabled by pre-coating either a flux composition or a brazing composition on a flat surface of an aluminum-extruded multi-cavity flat tube uniformly with excellent adhesion and transfer printing performance. At least one of the flat surfaces of said aluminum-extruded multi-cavity flat tube is coated with a flux composition comprising brazing flux and a synthetic resin based, as its main constituent, on a methacrylate homopolymer or a methacrylate copolymer, or alternatively with a brazing composition comprising a brazing flux, brazing metals, and said synthetic resin. In a preferred embodiment, such a coating is provided by applying to a surface of an aluminum-extruded multi-cavity flat tube said compositions as added to an organic solvent, having a molecular structure wherein the atomic ratio of carbon to oxygen is between 2 and 3, through a roll-transfer printing technique.
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