How to Remove Air Bubbles from Insulated Glass Sealant and What to Do If Air Bubbles Appear in Laminated Glass?
In the process of glass processing, production and installation, air bubble problems are common hidden dangers affecting glass quality and service effect. Especially in the production links of Insulated glass and Laminated glass, the appearance of air bubbles will not only reduce the sealing performance, safety of the glass, but also affect its aesthetics, bringing a great impact on the product qualification rate of glass factories. This article will detail the methods to remove air bubbles from insulated glass sealant and the treatment schemes for air bubbles in laminated glass, combining the actual production experience ofglass factories, to provide professional and operable solutions for industry practitioners and relevant users, helping to reduce air bubble hidden dangers and improve product quality.
I. Causes and Removal Methods of Air Bubbles in Insulated Glass Sealant
The sealing performance of Insulated glass mainly depends on the construction quality of the glass sealant. The generation of air bubbles is closely related to construction operations, material quality, environmental factors and equipment status. In the production process of glass factories, too fast sealant application, uneven mixing of sealant, equipment air leakage, improper control of environmental temperature and humidity, or impurities in the sealant itself and air bubbles not discharged in advance may lead to air bubbles in the insulated glass sealant layer. These air bubbles will damage the continuity of the sealant layer, reduce the sound insulation, heat insulation and waterproof performance of the insulated glass, and may lead to sealant layer falling off and water vapor infiltration in long-term use, affecting the service life of the glass.
For air bubbles in insulated glass sealant, targeted removal methods should be adopted according to the size, quantity and generation stage of the air bubbles, taking into account the convenience of operation and repair effect. The following are the common professional treatment methods used by glass factories:
1. Mild air bubbles (small, scattered and uncured): If the air bubbles are small, few in quantity and the glass sealant is not completely cured, the manual air exhaust method can be adopted. Prepare a disinfected needle or toothpick, gently pierce the top of the air bubble, slowly squeeze the sealant layer with a scraper to gradually discharge the air in the bubble, and then smooth the sealant layer with a scraper to ensure that the sealant layer is completely attached to the glass surface and avoid re-entrapping air. This method is suitable for the immediate repair after Insulated glass sealant application, with simple operation and no need for professional equipment. It can effectively reduce the impact of small air bubbles on the sealing effect, and is the most commonly used emergency treatment method in the production line of glass factories.
2. Moderate air bubbles (large quantity and partially cured): When there are many air bubbles or the glass sealant has been partially cured, and the manual air exhaust effect is not good, the local rework method is required. First, use a blade to completely scrape off the sealant layer containing air bubbles, clean the residual sealant and impurities on the glass surface to ensure that the glass surface is free of oil, dust and water. Then reselect high-quality glass sealant, control the sealant application speed to avoid air entrapment caused by too fast sealant application. During the sealant application process, a professional tool can be used to gently squeeze the sealant layer to discharge air in real time. After applying the sealant, smooth it with a scraper in time to ensure that the sealant layer is uniform and free of air bubbles. When dealing with such air bubbles, glass factories will pay special attention to the proportion of sealant and the control of environmental temperature and humidity to avoid secondary generation of air bubbles.
3. Severe air bubbles (large-area and fully cured): If there are large-area air bubbles in the insulated glass sealant layer and the sealant layer has been completely cured, it indicates that there is a serious operational error in the sealant application process. At this time, overall rework is required. Scrape off all the original sealant layer, check whether the sealant application equipment leaks air and whether the sealant is qualified, adjust the equipment parameters and construction process, and re-perform the sealant application operation. Glass factories will conduct strict inspection on such reworked products to ensure that the sealant layer of the repaired Insulated glass is well sealed without any air bubble hidden dangers, so as to avoid unqualified products flowing into the market.
In addition, when producing Insulated glass,glass factories will also take preventive measures to reduce the generation of air bubbles: select high-quality glass sealant from regular manufacturers, avoid using sealant containing impurities or expired; conduct static defoaming treatment on the sealant before application, or use a vacuum defoaming machine to remove air in the sealant; control the environmental temperature and humidity, avoid applying sealant in high temperature, high humidity or dusty environment; regularly inspect the sealant application equipment, timely fasten loose parts and clean the equipment filter screen to ensure the normal operation of the equipment, and reduce the generation of air bubbles from the source.
II. Causes and Treatment Schemes of Air Bubbles in Laminated Glass
Laminated glass is composed of two or more layers of glass bonded by intermediate films such as PVB and EVA. Air bubbles are one of the common defects in its production and use process, which are mainly divided into air bubbles generated during production and air bubbles appearing during use. The causes and treatment methods of the two types of air bubbles are quite different. Glass factories will take scientific and reasonable treatment measures according to the specific conditions of the air bubbles, taking into account the repair effect and product safety.
In the production process of Laminated glass in glass factories, the generation of air bubbles is mainly related to factors such as glass cleanliness, intermediate film quality, vacuum degree control and autoclave firing process: if the glass surface is not cleaned properly and there is oil, dust or water, it will lead to poor adhesion between the intermediate film and the glass, resulting in air bubbles; if the intermediate film is damp, aged or has quality defects, it will affect the adhesion effect and form air bubbles; incomplete vacuum pumping, air leakage of vacuum bag or blockage of air channel will lead to air residue and form air bubbles; improper control of autoclave firing temperature and pressure will lead to uneven melting of the intermediate film and generate air bubbles. In the process of use, the appearance of air bubbles in laminated glass is mostly due to edge seal failure, intermediate film aging, or external impact and high-temperature exposure, leading to air or water vapor infiltration and formation of air bubbles.
For the air bubble problem of Laminated glass, different treatment schemes should be adopted according to the position, size, cause and generation stage of the air bubbles. The following are the common professional treatment methods used by glass factories:
1. Mild air bubbles generated during production (small edge bubbles, not fully formed): If a small number of small air bubbles are found at the edge during the production of Laminated glass and the intermediate film is not completely melted, the vacuum system can be adjusted in time, the tightness of the vacuum bag and the smoothness of the air channel can be checked, the pre-vacuuming time can be extended to ensure that the air is completely discharged, and then the secondary firing can be carried out according to the standard firing process by adjusting the temperature and pressure of the autoclave, which can effectively eliminate the small edge air bubbles. In the production process,glass factories will arrange special personnel to monitor in real time, find and deal with such mild air bubbles in time to avoid the expansion of defects.
2. Moderate air bubbles generated during production (local bubbles, formed): If the air bubbles appear in the local area of Laminated glass and the bubbles are large, the local repair method can be adopted. First, clean the area with air bubbles according to the range 5-8 times the defect area, remove the excess intermediate film between the two layers of glass, perform needle pricking treatment on the air bubble area, then wrap it with burlap and air guide needle cotton, paste butyl sealant strip, lay PE vacuum film and check for no leakage. After pre-vacuuming for 20-25 minutes, push it into the autoclave for three-stage firing. After firing, remove the wrapping to complete the repair. This method can effectively repair local air bubbles, save raw materials and improve the product qualification rate of glass factories.
3. Severe air bubbles generated during production (middle bubbles, large-area bubbles): If air bubbles appear in the middle of Laminated glass or large-area air bubbles appear, it indicates that there are serious process defects in the production process. Such air bubbles cannot reach the qualified standard through repair. To ensure product safety and service performance, glass factories usually scrap such products to avoid unqualified products flowing into the market. At the same time, they will investigate the problems in the production links, adjust the process parameters such as glass cleaning, vacuum pumping and autoclave firing, and eliminate such problems from the source.
4. Air bubbles appearing during use: If air bubbles appear in Laminated glass during use, it is mostly due to edge seal failure or intermediate film aging. At this time, it is necessary to judge whether it can be repaired according to the condition of the air bubbles. If the air bubbles are small, few in quantity and no water intake or degumming occurs, professional personnel can be contacted for local seal repair to re-seal the glass edge and prevent air and water vapor from continuing to infiltrate; if the air bubbles are large, many in quantity, or degumming, water intake, glass breakage and other conditions have occurred, it cannot be repaired, and the entire Laminated glass needs to be replaced in time to avoid affecting the use safety.
III. Core Points of Air Bubble Prevention and Control in Glass Factories
For glass factories, the air bubble problem of Insulated glass and Laminated glass is more important to prevent than to repair. It can not only reduce the rework rate and production cost, but also improve product quality and market competitiveness. The core points of air bubble prevention and control in glass factories mainly include the following:
1. Raw material control: Strictly select high-quality raw materials such as glass, glass sealant and intermediate film, eliminate the use of expired, damp or defective raw materials, and reduce the possibility of air bubble generation from the source; conduct strict inspection on raw materials to ensure they meet the production standards.
2. Process optimization: Continuously optimize the sealant application process of Insulated glass and the bonding, vacuum and firing processes of Laminated glass, control the key parameters such as sealant application speed, sealant ratio, vacuum degree, temperature and pressure, standardize the operation process, and avoid air bubble generation caused by human operation errors.
3. Equipment maintenance: Regularly inspect, maintain and calibrate production equipment such as sealant applicators, vacuum machines and autoclaves, timely find and solve problems such as equipment air leakage, blockage and parameter abnormalities, ensure the normal operation of the equipment, and provide guarantee for air bubble prevention and control.
4. Environmental control: Control the temperature, humidity and dust content of the production workshop, avoid carrying out Insulated glass sealant application and Laminated glass bonding operations in high temperature, high humidity or dusty environment, and reduce the environmental factors leading to air bubble generation.
5. Quality inspection: Establish a perfect quality inspection system, conduct strict inspection on Insulated glass and Laminated glass in all links of production, timely find defects such as air bubbles, take targeted treatment measures, and avoid unqualified products leaving the factory.
In summary, the treatment of air bubbles in insulated glass sealant and laminated glass needs to adopt targeted methods according to the specific conditions of the air bubbles. The standardized production, strict quality control and scientific process optimization of glass factories are the key to reducing air bubble hidden dangers. Whether it is the sealant layer bubbles of Insulated glass or the middle bubbles of Laminated glass, only timely discovery, scientific treatment and source prevention and control can ensure the quality and use safety of glass products and improve the market competitiveness of glass factories.
