In the production process of aluminium trough insulating glass, the success of coating as a sealing butyl adhesive directly affects the quality and service life of insulating glass. In the actual production process, butyl rubber coating sometimes encounters the bubble phenomenon, and the harm caused by the bubble phenomenon is mainly two:

(1) The normal coating strip is interrupted, affecting the coating efficiency.

(2) Due to the production of a large number of tiny bubbles, the brightness of the surface of the strip is affected, resulting in burr phenomenon, which seriously affects the appearance of the aluminum spacer strip before the film is closed. Therefore, the elimination of bubbles is particularly important in the production process of insulating glass.

There are many reasons for bubbles in the process of coating butyl glue, which can be roughly divided into the following aspects:

(1) There are bubbles inside the finished butyl rubber. Because butyl adhesive is a semi-solid viscous adhesive, in the production process if mixed with bubbles are not treated or not thoroughly and the bubbles remain in the colloid, the bubbles can be discharged with the colloid from the coating head during the coating process, thus affecting the coating quality.

(2) If the butyl glue in the rubber cylinder is not drained, replace it with a new butyl glue. If the piston is withdrawn in the presence of butyl glue in the rubber cylinder, the butyl glue with excellent adhesion will form a mountain peak at the bottom of the rubber cylinder and the piston, and after pushing the new butyl glue, there will be a lot of bubbles between the mountain peak butyl glue and the new butyl glue, the difference is that the bubbles at the piston are less than the bubbles at the bottom of the rubber cylinder. Therefore, in the gluing process, the bubbles are larger and burrs are more after the glue is changed, and there are fewer bubbles near the end.

(3) The diameter of butyl colloid is too different from the diameter of the rubber cylinder. If the diameter of butyl glue is much smaller than the diameter of the cylinder, there is a large space between butyl glue and the inner wall of the cylinder and it is filled with a lot of air. Under the powerful mechanical extrusion of the piston, the outer wall of the gel expands irregularly, and part of the air is squeezed and sealed between the gel and the cylinder wall. However, the closed air cannot be discharged due to the obstruction of butyl adhesive, resulting in bubbles occurring at a certain interval during the butyl adhesive coating process.

(4) The temperature of the rubber cylinder and the rubber head is too high. Due to the presence of macromolecular organic substances in butyl rubber, if the temperature is too high, the organic substances will crack and produce small molecular substances, some of which exist in gaseous form at high temperature. If the butyl rubber coating operation is performed at this time, after the discharge of the rubber head, that is, the gas under high temperature and high pressure suddenly depressurized, its volume will expand rapidly, producing a large number of microbubbles, making the rubber strip appear as burr phenomenon.

Of course, there are many uncertainties about the causes of bubbles in the process of butyl rubber coating. As long as we follow the objective laws of things and conduct in-depth analysis, we can solve the problem of bubbles plaguing butyl rubber coating.