Bonding technology of polyurethane adhesive (Ⅱ)

2025,06,14

3. Roughening treatment

If the bonding surface is smooth, it is generally necessary to roughen it first to increase the contact area between Polyurethane Adhesive and substrate. Polyurethane adhesive permeates into the recesses or pores on the surface of the substrate, and after curing, it can be embedded like "nails, hooks and sticks", which can firmly stick the substrate together. Commonly used treatment methods include sand blasting, wood file coarsening and sandpaper grinding. However, if the bonding surface is treated too rough, the infiltration of polyurethane adhesive on the bonding surface will be affected, and there will be residues or bubbles in the recesses, which will reduce the bonding strength between polyurethane adhesive and the bonding surface. Moreover, it is easy to damage the substrate by treating the bonding surface with sand grinding, so it is suggested to change its surface properties by coating primer, etching and corona treatment to make it easy to be bonded by polyurethane adhesive.

4. Chemical treatment of metal surface

The metal surface can be derusted, degreased and slightly corroded at the same time. There are many available treatment agents, and acidic treatment solution is generally used. For example, for aluminum and aluminum alloys, the mixture of potassium dichromate/concentrated sulfuric acid/water can be soaked for 5-10 min, then washed and neutralized, and then washed and dried. For iron, concentrated sulfuric acid or hydrochloric acid can be mixed with water in a ratio of 1: 1, soaked at room temperature for 5-10 min, then washed with water and dried, or it can be treated with mixed solution of potassium dichromate/concentrated sulfuric acid/water.

Author:

Ms. Cherry

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348754229@qq.com

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