With the rapid development of economy and technology in China, the construction of large-scale water conservancy projects, high-rise buildings and the development of aerospace engineering need special performance elastic sealant as the bonding and sealing material of joints.
Polysulfide sealant is a high-grade sealing material made of liquid polysulfide rubber as main agent, plasticizer, reinforcing agent and vulcanizing agent. Polysulfide sealant has excellent properties of oil resistance, solvent resistance, aging resistance, acid and alkali resistance, heat resistance, water resistance, low air permeability, good elasticity and high adhesion to metal and nonmetal. It is mainly used for sealing of insulating glass, sealing and waterproofing of roof slab joints of high-rise buildings, as well as sealing and waterproofing of expansion joints of subway, tunnel, sewage treatment plant, airport runway and large-scale water conservancy projects. It has a broad application prospect.
Construction technology and precautions of polysulfide sealant:
1. Clean interface: no water, oil, dust, etc. Construction cannot be carried out in rainy days, and it is not suitable for construction when the temperature is below 5 ℃.
2. Even glue mixing: it is very important that there is no color difference. If the mixture is not uniform, it will cure slowly or not for a long time, or lose the adhesion, thus affecting the engineering quality.
3. Curing speed control: because the curing speed is affected by climatic conditions, it is better to do some small experiments in advance. If the curing speed is too fast (such as within 1 hour), the dosage of component B can be appropriately reduced; if the curing is too slow, the amount of component B can be appropriately increased.
4. In order to improve the engineering quality, a layer of special base treatment agent is applied on the bonded interface in advance, and then the sealant is embedded after it is dried.
5. Sealants have different bonding effects on different media, especially for natural stone. Therefore, if necessary, the bonded materials can be sent to the sealant manufacturer for testing before ordering, which can avoid unnecessary trouble to the project.
With the continuous development of China’s modernization construction and the improvement of people’s living standard, the application field of polysulfide sealant is expanding continuously. We should strive to improve the technical level and product quality to meet the needs of various projects.