Silicone sealant has been widely used in curtain wall, doors and windows, hollow glass, interior decoration and other construction fields, playing a role of bonding and sealing. In the process of application, we will come into contact with the concepts of structural adhesive, hollow adhesive, door and window adhesive, weather resistant adhesive, fire-proof adhesive, etc.
Door and window sealant is mainly used for sealing the joints between the door or window frame and glass, and between the frame and wall, which plays a role of sealing and water-proof. On the market, door and window sealant is almost a single component silicone sealant, which needs to react with the water vapor in the air to cure. The curing process is affected by the environmental temperature and humidity conditions at the same time, the lower the environmental temperature and humidity, the stronger the sealant The slower it will turn.
The door and window sealant shall bear the change of joint width and width, and it is required to have certain displacement ability and good weather resistance and aging resistance.
Fengjing group product technology research and development center, combined with many years of experience in the application of door and window sealant, is sorting out the following precautions in the construction of door and window sealant. Hope to get the attention of users.
1、 Choose the appropriate glue type according to the application situation
According to the curing principle, silicone sealant can be divided into two types: acid type and neutral type, and neutral type can be divided into dealcoholic type and ketoxime type.
Among them, acid adhesive is characterized by fast curing speed, but it will corrode metal base materials, and react with cement base materials or carbonate base materials (such as stone materials), so it is not suitable for such materials.
Neutral adhesive has a small smell and good adhesion to a variety of substrates. Alcohol based adhesive has a smaller smell than ketoxime based adhesive, which is more environmentally friendly. Therefore, it is more popular for indoor caulking and gluing or continuous gluing in the workshop. Because ketoxime type sealant will corrode the copper zinc material, the alcohol type sealant should be selected when sealing the joints of this kind of material.
Stone Sealing requires no pollution to the stone. It is better to select the special stone glue with stone sealing. It is better to select the anti mold glue with anti mold function in the bathroom and kitchen.
2、 Factors influencing curing of one component silicone sealant
Single component silicone sealant for doors and windows is hygroscopic curing type. It absorbs moisture in the air and crosslinks and solidifies after removing small molecules. Specifically, it has high temperature and humidity, fast curing, low temperature and humidity and slow curing.
Therefore, it is necessary to grasp the different performance of sealant under different environmental conditions for the use of good door and window glue. During the construction, the construction shall be carried out according to the construction environmental conditions recommended by the sealant manufacturer.
The recommended construction environment conditions for silicone sealant are: temperature 4 ℃ ~ 40 ℃, relative humidity 40% ~ 80%.
In spring, the weather in the north of China is dry and the humidity is low, and the curing speed of sealant may slow down obviously. It is suggested that the curing time after sealant construction can be extended properly during the construction process, and the large stress on the sealant joint after sealant construction should be avoided to cause the deformation of the sealant joint.
For the door and window assembly construction in the door and window factory, both sides of the door and window glazing need to be glued. Generally, the method is to construct one side first, turn over the other side after the sealant solidifies. For the construction of turning over, it is necessary to ensure that the sealant is cured to a certain extent to resist the deformation of the glue joint caused by turning over.
It is suggested that heating or humidification measures can be adopted in the construction process to improve indoor temperature and humidity conditions and accelerate the curing speed of sealant.
In spring, it is rainy and humid in the south of China with high humidity, which is easy to cause the surface moisture of the base material at the glue joint. If the surface of the base material is not dry enough before the sealant construction and there is water vapor, it may cause the sealant to bubble, and the moisture of the sealant will also affect the adhesive performance of the sealant, thus affecting the construction quality.
During the construction in wet weather, it is necessary to fully confirm that the substrate surface is dry before construction.
After the doors and windows are installed, first use polyurethane foam sealant (commonly known as styrofoam) to fill the gap between the window frame and the wall. After the foam is completely solidified, the excess foaming agent will be removed and then sealed with silicone sealant. If the foam does not solidify completely, the foaming will occur.
When the temperature difference between day and night is large, it is necessary to avoid the direct sunlight at noon for gluing. It can be done in the morning on the shady side and in the afternoon on the sunny side, or in the form of a shading net, which can effectively avoid wrinkling and bulging.
In summer, pay attention to timely correction. In summer, especially when the surface temperature of the base material is high, the surface drying speed of the glue will be accelerated, and the correction will not be timely, which will also affect the flatness of the glue surface.
3、 Preparation and precautions before sealant construction
1. Before the construction of the door and window sealant, it shall be ensured that the compatibility and adhesiveness test of the confidential sealant and the base material and relevant accessories are qualified. If the door and window surface is stained with oil, it shall be cleaned with water-soluble cleaning agent, and it is forbidden to scrub with rough or corrosive chemical liquid.
2. It is a normal physical phenomenon that the resistance to apply glue is increased and the hanging wall of the plastic bottle is also increased if the tip is not cut or the tip is very small. It can be solved by cutting the tip.
3. It is forbidden to cut several sharp mouths at the same time when the door and window glue is hard. If the sharp mouth is cut for a long time, it will form skin at the mouth of the bottle, which will affect the appearance of gluing. You should finish one and cut the other.
4. For soft packaging, it is recommended to cut off the buckle end with an art knife, and then install a sharp mouth for gluing. Some workers are used to shake off the buckle and apply glue directly. As the glue is in the production packaging process, there will inevitably be a small amount of surplus glue around the buckle. If the buckle is not cleaned and applied immediately, the rubber will be applied and the appearance will be affected.
5. Different types of glue can not be mixed at the same time, for example, alcohol type sealant and ketoxime type sealant can be used at the same time, ketoxime type will make alcohol type white glue yellowing, acid and ketoxime type glue mixing will cause porcelain white or transparent glue yellowing;
6. It should be noted that if the rubber sealing strip and other materials are contacted during gluing, grease may be separated from the surface of the glue to make the glue discolored; if gluing is required for the wall pasted with wallpaper, it should be tested in advance to prevent the wallpaper glue or paper from causing the glue discoloration, and neutral colored glue should be selected as far as possible.
7. The antifungal effect of the antifungal glue is closely related to the use occasions. If the use occasions are wet and dirty, the consumption of the antifungal agent in the antifungal glue is fast, and the antifungal time will be shortened.
8. During the storage period specified by the manufacturer, the quality and performance of the sealant after surface drying, debonding and curing meet the requirements of door and window assembly.
9. The joint design shall ensure full contact with the air during the curing period. The depth of gluing shall be less than half of the width of gluing, and the depth shall not exceed 1cm. Otherwise, the deep curing will be very slow, which will also affect the adhesive force.
For the deeper gap, measures such as multi-stage gluing and two-sided gluing can be taken. The thickness of the tape will also affect the speed of the fixed line. The coarser the tape is, the slower the curing will be.
At the same time, the curing speed of the adhesive strip is also different from that of the adhesive strip when it is applied on the substrate to check the bonding force. The adhesive strip contacts the water vapor on all sides, which is fast. Only one side of the adhesive strip contacts the water vapor on the substrate, so the curing will be slow.
10. Special silicone sealant for glass curtain wall shall be used for the sealant in contact with the second sealing of hollow glass, and the sealant containing white oil shall not be used to prevent the butyl adhesive from dissolving and tearing.
11. Glue should be full and ensure the thickness, not too thin, too thin to crack.
Everyone's home has windows, reasonable installation of windows can also achieve a good ventilation effect. In the process of installing windows, the window gluing skills must be understood by the installation personnel. If the steps of window gluing are not understood, it will affect the use effect of windows. Therefore, it is necessary to master the methods and skills of window gluing.
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