Problems needing attention in the use of the hotte

Problems that should be paid attention to in the use of butyl sealant

insulating glass integrates excellent characteristics such as heat insulation, sound insulation, lighting and so on. It is an effective energy-saving means of modern buildings. It not only simplifies the structural design of ventilation and heat preservation facilities such as air conditioning, reduces the cost of building decoration, but also increases the effective indoor space of buildings. With the rapid rise of glass curtain wall in China in the 1990s, the development of insulating glass industry has been accelerated. The application scope of insulating glass is constantly expanding. In addition to being widely used in glass curtain walls, automobiles, transportation, aircraft and other aspects, it has entered a large number of new buildings and ordinary people's homes, and people have higher and higher requirements for the quality of insulating glass. Insulating glass with long sealing life not only has better economic benefits, but also has stronger market competitiveness. Therefore, making high-quality and reliable insulating glass with excellent alloy structural steel has become a key issue pursued and studied by insulating glass manufacturers. At present, the manufacturing process of insulating glass is not perfect. Mastering and implementing the correct manufacturing process is the guarantee and premise of insulating glass quality

the application of butyl sealant is the first step and key link in making insulating glass, which determines the comprehensive quality performance of insulating glass products (whether it meets the five indicators of the national standard for insulating glass). The non drying sealant composed of butyl rubber and a small amount of polyisobutylene will not dry in the production of insulating glass, and can be mechanically applied. It is suitable for assembly line use. After coating, the adhesive layer will not dry and maintain permanent viscosity. At the same time, it has excellent heat and water resistance, will not flow under the sun and rain, and maintains the air tightness of insulating glass. Together with the second sealant, it forms an excellent moisture resistance system

in order to ensure the appearance and quality of insulating glass, the butyl sealant used has the following technical requirements:

1. Appropriate guaranteed butyl sealant products must be selected

2. Good initial adhesion and adhesion with glass

3. Good sealing performance

4. The coating must be uniform and the coating section must be consistent

- theoretical research and practical problem discussion and analysis

below is a brief discussion on the problems and solutions or suggestions of butyl sealant in use:

1 phenomenon: the butyl adhesive strip applied to the aluminum spacer strip has rough edges and is not neat

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

solutions or suggestions: check whether there are impurities at the outlet of the two nozzles or whether the nozzle is smooth

2 phenomenon: there is a gap (white line) between the butyl adhesive strip and the first sealant after lamination

cause: the first sealant is not applied in the correct way

solutions or suggestions: when applying the first layer of 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 insulating glass

3 phenomenon: the extrusion is not smooth after heating, and it is easy to break the glue (thread)

reason: the key to the use of butyl sealant is extrusion. Temperature control not only includes an 8-bit successive approximation converter system, but also is very important in the extrusion process. Whether the temperature control is appropriate directly affects the rheological state of butyl sealant in the whole processing process and affects the internal quality and beauty of products. Special attention should be paid to temperature. Too high temperature will cause the sealant to melt too much in January 2017, without strength or even unable to form at all (flowing phenomenon); The temperature is too low, the fluidity of the glue is poor, and the machine cannot squeeze the glue, which affects the construction progress. This is the main reason for the smooth extrusion. Another reason may be that the butyl sealant is mixed with bubbles in the manufacturing process, resulting in glue breaking during the extrusion process

solutions or suggestions: Generally speaking, the selection of temperature should be based on the extrusion temperature range provided by the manufacturer. The extruder temperature is generally set between 110-130 ℃ for the barrel and 112-132 ℃ for the head. In order to generate a certain pressure on the main machine to melt and extrude evenly, the temperature of the machine head is required to be higher than that of the barrel. The temperature has a certain hysteresis. During the adjustment, attention should be paid to that the heating and cooling should be carried out gradually. Before the coating starts, proper exhaust should be carried out to reduce internal bubbles and voids, so as to prevent bubbles from forming during extrusion and causing glue breaking

4 phenomenon: the extrusion temperature is controlled appropriately, but the adhesion between aluminum spacer and butyl sealant is poor or poor

cause: ⑴ the aluminum spacer strip or conveyor belt is not clean, with oil and dust

⑵ the belt is transmitted too fast, and the aluminum spacer is too late to glue

⑶ the aluminum partition frame is skewed, and it is difficult to pass through the glue applicator or the glue application position is incorrect

⑷ poor initial viscosity of sealant itself

solutions or suggestions:

⑴ clean and calibrate the aluminum spacer strip and the conveyor belt, and adjust the speed of the conveyor belt

⑵ adjust the gap between the two rubber nozzles in proportion

⑶ when coating, the aluminum spacer frame should be placed vertically to prevent the aluminum spacer strip from sticking due to the difficulty of passing through the glue nozzle or the incorrect glue position

⑷ butyl sealant is an elastic and viscous elastomer. It is extruded and adsorbed on the clean aluminum strip through appropriate temperature and pressure. The fused butyl sealant diffuses to the surface of the adherend, gradually wetting the surface of the adherend and penetrating into the surface pores. This is a physical process. In this process, butyl sealant and the adherend (aluminum strip) are only in line contact between the surfaces, and only after pressing can it be in surface contact with the adherend. Therefore, proper construction pressure and temperature are conducive to this process. It is worth noting that the adsorption of the adhesive on the aluminum strip takes a period of time (3 ~ 5min) to achieve the best bonding effect

II precautions

1. Open the original package and check whether there are obvious particles and sundries

2. Do not apply too fast to prevent it from being applied to the end

3. The pressing time can be readjusted if the coating is not finished or the pressing wheel is lifted, and the pressing time is too short

4. It is not easy to place the coated aluminum spacer frame for a long time, otherwise the effect of bonding and sealing will be affected

5. If the conveyor belt deviates, it should be corrected in time. If there is too much glue on the conveyor belt, it should be removed in time. If necessary, a small amount of paraffin can be applied to prevent sticking

6. After the first layer of sealant is applied, press it in a short time as far as possible to avoid the influence of ambient temperature on product bonding. The hollow glass that has not been rolled with the second layer of sealant should be placed horizontally. It can be placed vertically in a short time, but it cannot be collided to avoid unnecessary dislocation

7. Before making double-layer insulating glass, the necessary compatibility test must be carried out on the double-layer sealant to prevent the two kinds of sealant from dissolving