□ Preface

Butyl sealant application is the first and crucial step in the production of insulating glass, which determines the comprehensive performance of insulating glass products. In order to ensure the appearance and quality of insulating glass, there are the following technical requirements for the butyl sealant used:

□Suitable and quality guaranteed butyl sealant must be selected;

□Has good initial adhesion and adhesion to glass;

□Has good sealing performance;

□The coating must be uniform and the coating cross-section must be consistent；

□The application must be uniform, with a consistent cross-section and good compatibility with the matching sealant used.

□Theoretical research and practical problem exploration and analysis

Mastering and implementing the correct manufacturing process is the guarantee and prerequisite for the quality of insulating glass. Below is a brief discussion on the problems that are prone to occur in the use of butyl sealant and the corresponding solution or suggestion：

☑Apperance：The butyl adhesive strip applied to the aluminum spacer strip has rough edges and is not neat.

Reason：there may be impurities at the outlet of the two rubber nozzles or the rubber nozzle mouth may not be smooth.

Resolution or suggestion：Check if there are any impurities at the outlet of the two rubber nozzles or if the rubber nozzle mouth is smooth.

☑Apperance：There is a gap (white line) between the butyl adhesive strip after lamination and the second layer of sealant.

Reason:The second sealant was not applied correctly.

Resolution or suggestion：When applying the second layer sealant,apply appropriate force in one direction to prevent air from entering the sealant and reduce the insulating glass sealing performance.

☑Apperance:After heating, the extrusion is not smooth and it’s easy to break the adhesive (wire).

Reason：Extrusion is the key to using butyl sealant,and temperature control is very important during the extrusion process,the suitability of temperature control directly affects  butyl sealant rheological state throughout the entire processing process, affecting the internal quality and product aesthetics. Special attention should be paid to temperature.Excessive temperature can cause the sealant to melt excessively, lack strength, and even fail to form. The temperature is too low, the fluidity of the adhesive is poor, and the machine extrusion is not smooth, which affects the construction progress, which is the main reason for the unsmooth extrusion.

Resolution or suggestion：Generally speaking, temperature selection should be based on the extrusion temperature range provided by the manufacturer.the extruder temperature  is generally set between 100-150 ℃ for the barrel and 102-152 ℃ for the head. In order to generate a certain amount of pressure on the host machine and ensure uniform extrusion during melting, it is required that the head temperature be higher than the barrel temperature.

Temperature is lag,adjustment should pay attention. gradually carry out heating and cooling. Before coating, take appropriate exhaust to reduce internal bubbles and void bubbles may occur during extrusion of the house, causing adhesive breakage.

☑Apperance：Extrusion temperature control is appropriate, but the adhesion between the aluminum spacer strip and the butyl sealant is not good or poor.

Reason:

(1)The aluminum spacer strip or conveyor belt is not clean and has oil or dust.

(2)The belt conveyor is too fast, and the aluminum spacing strip cannot be coated in time.

(3) The aluminum spacer frame is skewed, it’s difficult for the nozzle to pass through or the adhesive position incorrect.

(4) Sealant itself has poor initial adhesion.

Resolution or suggestion：

(1)Clean and calibrate the aluminum spacer strip and conveyor belt, adjust the conveyor belt speed.

(2)Adjust the gap between the two rubber nozzles proportionally.

(3)When applying,Put aluminum spacing frame vertically to prevent the aluminum spacing strip from sticking to the adhesive due to difficulty in passing through the adhesive nozzle or incorrect adhesive position.

(4)Butyl sealant is an elastic and viscous elastomer that is extruded and sucked through appropriate temperature and pressure,It is attached to the clean aluminum spacer strip, and butyl sealant diffuses to the surface diffusion of the adherent. Gradually wet the surface of the adhesive and penetrate deeper into the surface,Therefore, appropriate construction pressure and temperature are beneficial.It is worth noting that adhesive adsorption on the aluminum spacer strip takes a period of time (3-5 minutes) to reach to achieve the best bonding effect

☑Apperance：Produced insulating glass shows butyl sealant flow (tears).

Reason：(1)The butyl sealant is not compatible with the external sealant.

(2)Insulating glass frame used sealant is not compatible with butyl sealant.

(3)Curtain wall used weatherproof sealant is not compatible with butyl sealant；

(4)Using unqualified butyl sealant.

Resolution or suggestion：

Select well-known brand sealants and use the same company's products as much as possible;

Perform necessary compatibility tests on sealants from different manufacturers before use (this compatibility test is for butyl sealants,External insulating glass sealant, sealant used for framing, or weatherproof sealant used for curtain wall installation

compatibility test between).

□  Important notes

☑Open the original packaging and check for obvious particles and debris.

☑Do not apply too quickly to prevent incomplete application.

☑If the coating cannot reach the end or the pressing wheel is lifted;the pressing time is too short, the pressing wheel time can be adjusted again.

☑ The coated aluminum spacer frame placement time should not be too long, otherwise it will affect the bonding and sealing effect.

☑Correct the conveyor belt deviates timely,Remove timely, if there is too much adhesive on the conveyor belt. If necessary, a small amount of paraffin can be applied to prevent the belt from sticking.

☑After applying the first layer of sealant, try to press it in a short period of time to avoid the impact of environmental temperature on product adhesion. Hollow glass after rolling but not be coated with the second layer of sealant should be placed horizontally, and can be placed vertically in a short time, but should not collide to avoid unnecessary misalignment.

☑Before making double-layer insulating glass, necessary compatibility tests must be carried out on the double-layer sealant to prevent bubbles from forming when the two types of sealant dissolve and causing adhesive breakage.