Problems that are prone to occur in the use of butyl sealant

11 / 04 / 2022

Problems that are prone to occur in the use of butyl sealant
The problems that are prone to occur in the use of butyl sealants, analyze the reasons and give solutions.
Phenomenon 1: The butyl tape coated on the aluminum spacer has burrs and is not neat.
Reason: There may be impurities at the exits of the two nozzles or the nozzles are not smooth.
Solution: Check whether there are impurities at the exits of the two nozzles or whether the nozzles are smooth.
Phenomenon 2: There is a gap (white line) between the butyl rubber strip and the sealant after the lamination.
Cause: The sealant was not applied correctly.
Solution: When applying the sealant, it should be applied with appropriate force and in one direction to prevent air from being wrapped in the glue and reduce the sealing performance of the insulating glass.
Phenomenon 3: Extrusion is not smooth after heating, and it is easy to break the glue (broken wire).
Reason: The key to the use of butyl sealant lies in extrusion. Temperature control is very important in the extrusion process. Whether the temperature control is appropriate directly affects the rheological state of the butyl sealant in the entire processing process and affects the inherent properties of the product. Quality and aesthetics, special attention should be paid to temperature. If the temperature is too high, the sealant will melt too much, without strength or even unable to form at all (flow phenomenon); if the temperature is too low, the fluidity of the glue will be poor, and the machine will not be able to extrude the glue, which will affect the construction progress, which is the main reason for the unsmooth extrusion. . Another reason may be that the butyl sealant contains air bubbles in the manufacturing process, which causes the glue to break during the extrusion process.
Solution: The selection of temperature Generally speaking, the extrusion temperature range provided by the manufacturer is appropriate. The temperature of the extruder is generally set between 110-130 °C for the barrel and 112-132 °C for the head. In order to make the main machine generate a certain pressure and extrude the melt evenly, the temperature of the head is required to be higher than the temperature of the barrel. The temperature has a certain hysteresis. During the adjustment, it should be noted that the heating and cooling should be carried out gradually. Before the coating starts, it should be properly vented to reduce the internal air bubbles and voids, and prevent the glue from breaking due to air bubbles during extrusion.
Phenomenon 4: The extrusion temperature is properly controlled, but the adhesion between the aluminum spacer and the butyl sealant is not good or the adhesiveness is poor.
Reasons: The aluminum spacer or conveyor belt is not clean and has oil and dust; the belt is conveyed too fast, and the aluminum spacer is too late to apply glue; Poor viscosity.
Solution: Clean and proofread the aluminum spacer and conveyor belt, adjust the speed of the conveyor belt; adjust the gap between the two glue nozzles in proportion; the aluminum spacer frame should be placed vertically during coating to prevent the glue nozzle from being difficult to pass or apply glue The non-adhesive phenomenon of aluminum spacer caused by incorrect position; Butyl sealant is both elastic and viscous elastomer, which is extruded and adsorbed on the clean aluminum strip through suitable temperature and pressure, and the molten butyl The glue spreads to the surface of the adherend, gradually wets the surface of the adherend and penetrates into the surface pores. This is a physical process. In this process, the butyl glue and the adherend (aluminum strip) are only in line contact between the surfaces. , and can only be in surface contact with the adherend after pressing. Therefore, suitable construction pressure and temperature are beneficial to the progress of this process. It is worth noting that the adsorption of the glue on the aluminum strip takes a period of time (3-5MIN) to achieve the bonding effect.